ORCID Profile
0000-0002-0276-6064
Current Organisation
University of Western Australia
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Marine and Estuarine Ecology (incl. Marine Ichthyology) | Ecology | Environmental Rehabilitation (excl. Bioremediation) | Environmental Science and Management | Ecological Impacts of Climate Change | Population Ecology | Marine And Estuarine Ecology (Incl. Marine Ichthyology) | Population, Ecological and Evolutionary Genetics | Ecosystem Function | Genetics | Gene Expression (incl. Microarray and other genome-wide approaches) | Ecological Physiology | Ecological Applications | Phycology | Artificial Intelligence and Image Processing | Geochronology And Isotope Geochemistry | Natural Resource Management | Environmental Impact Assessment | Biological Oceanography | Environmental Management And Rehabilitation | Terrestrial Ecology | Environmental Impact Assessment | Environmental Management | Environmental Monitoring | Conservation And Biodiversity | Freshwater Ecology | Adaptive Agents and Intelligent Robotics | Palaeoclimatology | Environmental Technologies | Pattern Recognition and Data Mining | Computer Vision | Climatology (Incl. Palaeoclimatology) | Isotope Geochemistry |
ANZSRC Socio-Economic Objective (SEO)
Marine Flora, Fauna and Biodiversity | Rehabilitation of Degraded Coastal and Estuarine Environments | Ecosystem Assessment and Management of Marine Environments | Integrated (ecosystem) assessment and management | Ecosystem Adaptation to Climate Change | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Coastal and Estuarine Flora, Fauna and Biodiversity | Climate change | Living resources (incl. impacts of fishing on non-target species) | Living resources (flora and fauna) | Computer Software and Services not elsewhere classified | Integrated (ecosystem) assessment and management | Estuarine and lagoon areas | Rehabilitation of degraded coastal and estuarine areas | Climate variability | Flora, Fauna and Biodiversity at Regional or Larger Scales | Integrated (ecosystem) assessment and management | Ecosystem Assessment and Management of Coastal and Estuarine Environments | Land and water management | Marine protected areas | Integrated (ecosystem) assessment and management | Expanding Knowledge in Technology |
Related Links
Publications
Seasonal links between metabolites and traditional seagrass metrics in the seagrass Halophila ovalis in an estuarine system
Publisher: Elsevier BV
Date: 10-2022
Assemblage turnover and taxonomic sufficiency of subtidal macroalgae at multiple spatial scales
Publisher: Elsevier BV
Date: 03-2010
Changes in seagrass cover on Success and Parmelia Banks, Western Australia between 1965 and 1995.
Publisher: Elsevier BV
Date: 03-2000
Highway or country road: algal recruitment with distance from an island reef
Publisher: Cambridge University Press (CUP)
Date: 10-2004
DOI: 10.1017/S0025315404010136H
Abstract: Subtidal macroalgal assemblages differed among islands within the Recherche Archipelago, Western Australia, with respect to species biomass. To investigate whether macroalgal populations were maintained locally, settlement plates were moored in 10 to 15 m depths at a reef s led for macroalgal ersity, and 20, 50, 100, and 500 m away from the reef. Plates were retrieved after eight months and assemblage differences were compared with distance from the s led reef. Macroalgal richness decreased with distance from an island assemblage and molluscan richness increased. At 500 m away, the number of algal recruits was negligible and the number of bivalves was relatively high.
The role of hydrodynamics on seed dispersal in seagrasses
Publisher: Wiley
Date: 23-07-2012
Effects of sediment burial on tropical ruderal seagrasses are moderated by clonal integration
Publisher: Elsevier BV
Date: 12-2011
Determining light stress responses for a tropical multi-species seagrass assemblage
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.MARPOLBUL.2018.01.060
Abstract: Existing mitigations to address deterioration in water clarity associated with human activities are based on responses from single seagrass species but may not be appropriate for erse seagrass assemblages common to tropical waters. We present findings from a light experiment designed to determine the effects of magnitude and duration of low light on a mixed tropical seagrass assemblage. Mixed assemblages of three commonly co-occurring Indo-West Pacific seagrasses, Cymodocea serrulata, Halodule uninervis and Halophila ovalis were grown in climate-controlled tanks, where replicate pots were subjected to a gradient in light availability (0.9-21.6 mols PAR m
Tissue-specific transcriptome profiles identify functional differences key to understanding whole plant response to life in variable salinity
Publisher: The Company of Biologists
Date: 15-08-2022
DOI: 10.1242/BIO.059147
Abstract: Plants endure environmental stressors via adaptation and phenotypic plasticity. Studying these mechanisms in seagrasses is extremely relevant as they are important primary producers and functionally significant carbon sinks. These mechanisms are not well understood at the tissue level in seagrasses. Using RNA-seq, we generated transcriptome sequences from tissue of leaf, basal leaf meristem and root organs of Posidonia australis, establishing baseline in situ transcriptomic profiles for tissues across a salinity gradient. S les were collected from four P. australis meadows growing in Shark Bay, Western Australia. Analysis of gene expression showed significant differences between tissue types, with more variation among leaves than meristem or roots. Gene ontology enrichment analysis showed the differences were largely due to the role of photosynthesis, plant growth and nutrient absorption in leaf, meristem and root organs, respectively. Differential gene expression of leaf and meristem showed upregulation of salinity regulation processes in higher salinity meadows. Our study highlights the importance of considering leaf meristem tissue when evaluating whole-plant responses to environmental change. This article has an associated First Person interview with the first author of the paper.
Historical processes and contemporary ocean currents drive genetic structure in the seagrass T halassia hemprichii in the Indo‐Australian Archipelago
Publisher: Wiley
Date: 02-2017
DOI: 10.1111/MEC.13966
Abstract: Understanding spatial patterns of gene flow and genetic structure is essential for the conservation of marine ecosystems. Contemporary ocean currents and historical isolation due to Pleistocene sea level fluctuations have been predicted to influence the genetic structure in marine populations. In the Indo-Australian Archipelago (IAA), the world's hotspot of marine bio ersity, seagrasses are a vital component but population genetic information is very limited. Here, we reconstructed the phylogeography of the seagrass Thalassia hemprichii in the IAA based on single nucleotide polymorphisms (SNPs) and then characterized the genetic structure based on a panel of 16 microsatellite markers. We further examined the relative importance of historical isolation and contemporary ocean currents in driving the patterns of genetic structure. Results from SNPs revealed three population groups: eastern Indonesia, western Indonesia (Sunda Shelf) and Indian Ocean while the microsatellites supported five population groups (eastern Indonesia, Sunda Shelf, Lesser Sunda, Western Australia and Indian Ocean). Both SNPs and microsatellites showed asymmetrical gene flow among population groups with a trend of southwestward migration from eastern Indonesia. Genetic ersity was generally higher in eastern Indonesia and decreased southwestward. The pattern of genetic structure and connectivity is attributed partly to the Pleistocene sea level fluctuations modified to a smaller level by contemporary ocean currents.
Seed bank dynamics and quality in the seagrass Halophila ovalis along estuarine salinity gradients—a case in the Swan-Canning Estuary
Publisher: Frontiers Media SA
Date: 22-11-2022
DOI: 10.3389/FMARS.2022.1025615
Abstract: The seed bank of Halophila ovalis is crucial for resilience to disturbance through re-establishment. Understanding seasonal changes in abundance and quality of seeds in natural seed banks is critical for seed-based restoration. We selected an estuary in southwestern Australia and investigated the seasonal changes of seed distribution and viability in H. ovalis seed banks. We also adapted an X-ray viability test used for terrestrial seeds to test the viability of H. ovalis seeds. We then simulated the effect of low salinity on seed viability through a short-term indoor experiment. Seed density was significantly different between sites and seasons (0 to 43590 seeds·m -2 ), and the highest seed density in the seed banks was found after the reproductive season (May). The proportion of viable seeds in the seed bank was less than 22%, and was not subjected to substantial seasonal variability. The density of seeds in the seed bank decreased in spring, which indicated winter conditions were not prompt seed loss. We also predicted that extreme rainfall events and the resulting extremely low salinity would significantly reduce seed viability, and could decrease in seed germination limit population recruitment. As it rapidly colonizes marine sediments from seeds, H. ovalis was considered an ideal seagrass for restoration purposes. Our results provide physiological information for H. ovalis seed banks to support seed-based restoration plans. Such understanding would enable accurate predictions about seagrass population resilience to extreme climate events in estuaries, where variable and extremely low salinity may limit seagrass population recovery from seeds through decreasing their viability.
Effects of shelter and enrichment on the ecology and nutrient cycling of microbial communities of subtidal carbonate sediments
Publisher: Oxford University Press (OUP)
Date: 11-01-2012
DOI: 10.1111/J.1574-6941.2011.01267.X
Abstract: The interactions between physical disturbances and biogeochemical cycling are fundamental to ecology. The benthic microbial community controls the major pathway of nutrient recycling in most shallow-water ecosystems. This community is strongly influenced by physical forcing and nutrient inputs. Our study tests the hypotheses that benthic microbial communities respond to shelter and enrichment with (1) increased biomass, (2) change in community composition and (3) increased uptake of inorganic nutrients from the water column. Replicate in situ plots were sheltered from physical disturbance and enriched with inorganic nutrients or left without additional nutrients. At t(0) and after 10 days, sediment-water fluxes of nutrients, O(2) and N(2) , were measured, the community was characterized with biomarkers. Autochthonous benthic microalgal (BMA) biomass increased 30% with shelter and a natural fivefold increase in nutrient concentration biomass did not increase with greater enrichment. Diatoms remained the dominant taxon of BMA, suggesting that the sediments were not N or Si limited. Bacteria and other heterotrophic organisms increased with enrichment and shelter. Daily exchanges of inorganic nutrients between sediments and the water column did not change in response to shelter or nutrient enrichment. In these sediments, physical disturbance, perhaps in conjunction with nutrient enrichment, was the primary determinant of microbial biomass.
Marine ecological processes, 2nd Edn.
Publisher: Elsevier BV
Date: 04-1996
Seeds in motion
Publisher: Wiley
Date: 12-2018
DOI: 10.1111/MEC.14939
Abstract: Movement is fundamental to the ecology and evolutionary dynamics within species. Understanding movement through seed dispersal in the marine environment can be difficult due to the high spatial and temporal variability of ocean currents. We employed a mutually enriching approach of population genetic assignment procedures and dispersal predictions from a hydrodynamic model to overcome this difficulty and quantify the movement of dispersing floating fruit of the temperate seagrass Posidonia australis Hook.f. across coastal waters in south-western Australia. Dispersing fruit cohorts were collected from the water surface over two consecutive years, and seeds were genotyped using microsatellite DNA markers. Likelihood-based genetic assignment tests were used to infer the meadow of origin for seed cohorts and in iduals. A three-dimensional hydrodynamic model was coupled with a particle transport model to simulate the movement of fruit at the water surface. Floating fruit cohorts were mainly assigned genetically to the nearest meadow, but significant genetic differentiation between cohort and most likely meadow of origin suggested a mixed origin. This was confirmed by genetic assignment of in idual seeds from the same cohort to multiple meadows. The hydrodynamic model predicted 60% of fruit dispersed within 20 km, but that fruit was physically capable of dispersing beyond the study region. Concordance between these two independent measures of dispersal provides insight into the role of physical transport for long distance dispersal of fruit and the consequences for spatial genetic structuring of seagrass meadows.
Thirty critical research needs for managing an ecologically and culturally unique remote marine environment
Publisher: Elsevier BV
Date: 10-2021
Advances in approaches to seagrass restoration in Australia
Publisher: Wiley
Date: 2021
DOI: 10.1111/EMR.12452
Abstract: Three case studies involving two temperate Australian seagrass species – Pondweed ( Ruppia tuberosa ) and Ribbon Weed ( Posidonia australis ) – highlight different approaches to their restoration. Seeds and rhizomes were used in three collaborative programmes to promote new approaches to scale up restoration outcomes.
Spatial modeling reveals a growing threat to the world's largest rhodolith beds
Publisher: Elsevier BV
Date: 02-2023
Automatic detection of Western rock lobster using synthetic data
Publisher: Oxford University Press (OUP)
Date: 22-11-2019
Abstract: Underwater imaging is being extensively used for monitoring the abundance of lobster species and their bio ersity in their local habitats. However, manual assessment of these images requires a huge amount of human effort. In this article, we propose to automate the process of lobster detection using a deep learning technique. A major obstacle in deploying such an automatic framework for the localization of lobsters in erse environments is the lack of large annotated training datasets. Generating synthetic datasets to train these object detection models has become a popular approach. However, the current synthetic data generation frameworks rely on automatic segmentation of objects of interest, which becomes difficult when the objects have a complex shape, such as lobster. To overcome this limitation, we propose an approach to synthetically generate parts of the lobster. To handle the variability of real-world images, these parts were inserted into a set of erse background marine images to generate a large synthetic dataset. A state-of-the-art object detector was trained using this synthetic parts dataset and tested on the challenging task of Western rock lobster detection in West Australian seas. To the best of our knowledge, this is the first automatic lobster detection technique for partially visible and occluded lobsters.
Variation in abundances of herbivorous invertebrates in temperate subtidal rocky reef habitats
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/MF03057
Abstract: The present study assessed variation in the abundances of large herbivorous invertebrates in south-western Australia. There was some habitat partitioning between different parts of the reef: of the most frequently recorded species, the sea urchins Phyllacanthus irregularis and Centrostephanus tenuispinus were found primarily at the base of steep rock faces, whereas the gastropods Turbo torquatus and Australium squamifera were found primarily on open sections of reef. The sea urchin Heliocidaris erythrogramma was evenly distributed between these two habitats. For C. tenuispinus and H. erythrogramma, differences among locations (separated by tens to hundreds of kilometers) were the main source of variation in abundances. Phyllacanthus irregularis was more evenly distributed among locations. Abundances of sea urchins at each reef varied little over 26 months, suggesting low mortality and low recruitment. Turbo torquatus and A. squamifera varied significantly in abundance among reefs separated by 10 km, although these differences were influenced by fluctuations over time. Broad patterns in abundances were evident: overall, abundances of herbivorous invertebrates were low, but certain areas supported high abundances. This suggests that herbivory may be a minor process in this region however, the importance of herbivory at reefs with and without high abundances of herbivores deserves further attention.
Knowledge gaps in tropical Southeast Asian seagrass systems
Publisher: Elsevier BV
Date: 03-2011
Managing seagrass resilience under cumulative dredging affecting light: Predicting risk using dynamic Bayesian networks
Publisher: Wiley
Date: 21-11-2018
A Global Crisis for Seagrass Ecosystems
Publisher: Oxford University Press (OUP)
Date: 2006
Disturbance Is an Important Driver of Clonal Richness in Tropical Seagrasses
Publisher: Frontiers Media SA
Date: 05-12-2017
Too hot to handle: unprecedented seagrass death driven by marine heatwave in a World Heritage Area
Publisher: Wiley
Date: 08-04-2020
DOI: 10.1111/GCB.15065
Interactions between filamentous turf algae and coralline algae are modified under ocean acidification
Publisher: Elsevier BV
Date: 07-2014
Turban snails as habitat for foliose algae: contrasting geographical patterns in species richness
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/MF09184
Abstract: Understanding patterns of species richness is a major goal for ecologists, especially in space-limited habitats where many organisms live on top of others (epibiosis, e.g. by algae growing on gastropods in marine environments). We tested the hypotheses that species richness of epiflora on the gastropod Turbo torquatus would not differ between regions with similarly rich algal floras, and that epifloral richness would increase with increasing gastropod size. Macroalgal floras of Hamelin Bay (HB), Marmion (M), Jurien Bay (JB) and Kalbarri (K), Western Australia, ranged from ∼20 to 40 species reef–1 (JB = HB = M ≥ K). Epiflora on small T. torquatus (shell area cm2) did not differ among regions but epifloral richness increased with increasing basibiont size. Large T. torquatus ( cm2) were only found in Hamelin Bay and Marmion, where epifloral richness differed substantially. Epifloral richness was positively related to basibiont size in Marmion but not in Hamelin Bay. However, densities of patellid limpets on large T. torquatus were ∼4× higher in Hamelin Bay than in Marmion, implying that limpet grazing suppresses epifloral richness. Epifloral richness on turbinids is not simply associated with regional species pools or gastropod size rather, biological interactions at the scale of in idual basibionts apparently govern broad scale patterns of epibiosis.
Recovery Dynamics of the Seagrass Zostera marina Following Mass Mortalities from Two Extreme Climatic Events
Publisher: Springer Science and Business Media LLC
Date: 19-08-2020
Spatial structure of seagrass suggests that size-dependent plant traits have a strong influence on the distribution and maintenance of tropical multispecies meadows
Publisher: Public Library of Science (PLoS)
Date: 31-01-2014
Low light availability alters root exudation and reduces putative beneficial microorganisms in seagrass roots
Publisher: Frontiers Media SA
Date: 11-01-2018
Population genetic structure of the Pocillopora damicornis morphospecies along Ningaloo Reef, Western Australia
Publisher: Inter-Research Science Center
Date: 22-10-2014
DOI: 10.3354/MEPS10893
How does burrowing by the isopod Limnoria agrostisa (Crustacea: Limnoriidae) affect the leaf canopy of the southern Australian seagrass Amphibolis griffithii?
Publisher: Springer Science and Business Media LLC
Date: 10-10-2008
A comparison of temperate reef fish assemblages recorded by three underwater stereo-video techniques
Publisher: Springer Science and Business Media LLC
Date: 26-08-2005
Carbon, nitrogen and phosphorus storage in subtropical seagrass meadows: Examples from Florida Bay and Shark Bay
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/MF12101
Abstract: Seagrass meadows in Florida Bay and Shark Bay contain substantial stores of both organic carbon and nutrients. Soils from both systems are predominantly calcium carbonate, with an average of 82.1% CaCO3 in Florida Bay compared with 71.3% in Shark Bay. Soils from Shark Bay had, on average, 21% higher organic carbon content and 35% higher phosphorus content than Florida Bay. Further, soils from Shark Bay had lower mean dry bulk density (0.78 ± 0.01 g mL–1) than those from Florida Bay (0.84 ± 0.02 mg mL–1). The most hypersaline regions of both bays had higher organic carbon content in surficial soils. Profiles of organic carbon and phosphorus from Florida Bay indicate that this system has experienced an increase in P delivery and primary productivity over the last century in contrast, decreasing organic carbon and phosphorus with depth in the soil profiles in Shark Bay point to a decrease in phosphorus delivery and primary productivity over the last 1000 y. The total ecosystem stocks of stored organic C in Florida Bay averages 163.5 MgCorg ha–1, lower than the average of 243.0 MgCorg ha–1 for Shark Bay but these values place Shark and Florida Bays among the global hotspots for organic C storage in coastal ecosystems.
Temperature Stratification and Monochromatic Light Break Dormancy and Facilitate On-Demand In Situ Germination in the Seagrass Halophila ovalis, with Seed Viability Determined by a Novel X-Ray Analysis
Publisher: Springer Science and Business Media LLC
Date: 15-10-2021
Seagrass ecosystem trajectory depends on the relative timescales of resistance, recovery and disturbance
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.MARPOLBUL.2017.09.006
Abstract: Seagrass ecosystems are inherently dynamic, responding to environmental change across a range of scales. Habitat requirements of seagrass are well defined, but less is known about their ability to resist disturbance. Specific means of recovery after loss are particularly difficult to quantify. Here we assess the resistance and recovery capacity of 12 seagrass genera. We document four classic trajectories of degradation and recovery for seagrass ecosystems, illustrated with ex les from around the world. Recovery can be rapid once conditions improve, but seagrass absence at landscape scales may persist for many decades, perpetuated by feedbacks and/or lack of seed or plant propagules to initiate recovery. It can be difficult to distinguish between slow recovery, recalcitrant degradation, and the need for a window of opportunity to trigger recovery. We propose a framework synthesizing how the spatial and temporal scales of both disturbance and seagrass response affect ecosystem trajectory and hence resilience.
Recruitment of coralline crusts and filamentous turf algae in the Galapagos archipelago: effect of simulated scour, erosion and accretion
Publisher: Elsevier BV
Date: 04-1991
The movement ecology of seagrasses
Publisher: The Royal Society
Date: 22-11-2014
Abstract: A movement ecology framework is applied to enhance our understanding of the causes, mechanisms and consequences of movement in seagrasses: marine, clonal, flowering plants. Four life-history stages of seagrasses can move: pollen, sexual propagules, vegetative fragments and the spread of in iduals through clonal growth. Movement occurs on the water surface, in the water column, on or in the sediment, via animal vectors and through spreading clones. A capacity for long-distance dispersal and demographic connectivity over multiple timeframes is the novel feature of the movement ecology of seagrasses with significant evolutionary and ecological consequences. The space–time movement footprint of different life-history stages varies. For ex le, the distance moved by reproductive propagules and vegetative expansion via clonal growth is similar, but the timescales range exponentially, from hours to months or centuries to millennia, respectively. Consequently, environmental factors and key traits that interact to influence movement also operate on vastly different spatial and temporal scales. Six key future research areas have been identified.
Genomic comparison of two independent seagrass lineages reveals habitat-driven convergent evolution
Publisher: Oxford University Press (OUP)
Date: 18-04-2018
DOI: 10.1093/JXB/ERY147
Dynamic Bayesian network inferencing for non-homogeneous complex systems
Publisher: Oxford University Press (OUP)
Date: 26-05-2018
DOI: 10.1111/RSSC.12228
Abstract: Dynamic Bayesian networks (DBNs) provide a versatile method for predictive, whole-of-systems modelling to support decision makers in managing natural systems subject to anthropogenic disturbances. However, DBNs typically assume a homogeneous Markov chain which we show can limit the dynamics that can be modelled especially for complex ecosystems that are susceptible to regime change (i.e. change in state transition probabilities). Such regime changes can occur as a result of exogenous inputs and/or because of past system states the latter is known as path dependence. We develop a method for non-homogeneous DBN inference to capture the dynamics of potentially path-dependent ecosystems. The method enables dynamic updates of DBN parameters at each time slice in computing posterior marginal probabilities given evidence for forward inference. An approximate algorithm for forward–backward inference is also provided noting that convergence is not guaranteed in a path-dependent system. We demonstrate the methods on a seagrass dredging case-study and show that the incorporation of path dependence enables conditional absorption into and release from the zero state in line with ecological observations. The model helps managers to develop practical ways to manage the marked effects of dredging on high value seagrass ecosystems.
A review of protocols for the experimental release of kelp (Laminariales) zoospores
Publisher: Wiley
Date: 20-06-2019
DOI: 10.1002/ECE3.5389
Feedback between sediment and light for seagrass: Where is it important?
Publisher: Wiley
Date: 24-06-2016
DOI: 10.1002/LNO.10319
Regional-scale patterns of mobile invertebrate assemblage structure on artificial habitats off Western Australia
Publisher: Elsevier BV
Date: 04-2014
Accelerating loss of seagrasses across the globe threatens coastal ecosystems
Publisher: Proceedings of the National Academy of Sciences
Date: 28-07-2009
Abstract: Coastal ecosystems and the services they provide are adversely affected by a wide variety of human activities. In particular, seagrass meadows are negatively affected by impacts accruing from the billion or more people who live within 50 km of them. Seagrass meadows provide important ecosystem services, including an estimated $1.9 trillion per year in the form of nutrient cycling an order of magnitude enhancement of coral reef fish productivity a habitat for thousands of fish, bird, and invertebrate species and a major food source for endangered dugong, manatee, and green turtle. Although in idual impacts from coastal development, degraded water quality, and climate change have been documented, there has been no quantitative global assessment of seagrass loss until now. Our comprehensive global assessment of 215 studies found that seagrasses have been disappearing at a rate of 110 km 2 yr −1 since 1980 and that 29% of the known areal extent has disappeared since seagrass areas were initially recorded in 1879. Furthermore, rates of decline have accelerated from a median of 0.9% yr −1 before 1940 to 7% yr −1 since 1990. Seagrass loss rates are comparable to those reported for mangroves, coral reefs, and tropical rainforests and place seagrass meadows among the most threatened ecosystems on earth.
Timing anthropogenic stressors to mitigate their impact on marine ecosystem resilience
Publisher: Springer Science and Business Media LLC
Date: 02-11-2017
DOI: 10.1038/S41467-017-01306-9
Abstract: Better mitigation of anthropogenic stressors on marine ecosystems is urgently needed to address increasing bio ersity losses worldwide. We explore opportunities for stressor mitigation using whole-of-systems modelling of ecological resilience, accounting for complex interactions between stressors, their timing and duration, background environmental conditions and biological processes. We then search for ecological windows, times when stressors minimally impact ecological resilience, defined here as risk, recovery and resistance. We show for 28 globally distributed seagrass meadows that stressor scheduling that exploits ecological windows for dredging c aigns can achieve up to a fourfold reduction in recovery time and 35% reduction in extinction risk. Although the timing and length of windows vary among sites to some degree, global trends indicate favourable windows in autumn and winter. Our results demonstrate that resilience is dynamic with respect to space, time and stressors, varying most strongly with: (i) the life history of the seagrass genus and (ii) the duration and timing of the impacting stress.
Isolation by resistance across a complex coral reef seascape
Publisher: The Royal Society
Date: 07-08-2015
Abstract: A detailed understanding of the genetic structure of populations and an accurate interpretation of processes driving contemporary patterns of gene flow are fundamental to successful spatial conservation management. The field of seascape genetics seeks to incorporate environmental variables and processes into analyses of population genetic data to improve our understanding of forces driving genetic ergence in the marine environment. Information about barriers to gene flow (such as ocean currents) is used to define a resistance surface to predict the spatial genetic structure of populations and explain deviations from the widely applied isolation-by-distance model. The majority of seascape approaches to date have been applied to linear coastal systems or at large spatial scales (more than 250 km), with very few applied to complex systems at regional spatial scales (less than 100 km). Here, we apply a seascape genetics approach to a peripheral population of the broadcast-spawning coral Acropora spicifera across the Houtman Abrolhos Islands, a high-latitude complex coral reef system off the central coast of Western Australia. We coupled population genetic data from a panel of microsatellite DNA markers with a biophysical dispersal model to test whether oceanographic processes could explain patterns of genetic ergence. We identified significant variation in allele frequencies over distances of less than 10 km, with significant differentiation occurring between adjacent sites but not between the most geographically distant ones. Recruitment probabilities between sites based on simulated larval dispersal were projected into a measure of resistance to connectivity that was significantly correlated with patterns of genetic ergence, demonstrating that patterns of spatial genetic structure are a function of restrictions to gene flow imposed by oceanographic currents. This study advances our understanding of the role of larval dispersal on the fine-scale genetic structure of coral populations across a complex island system and applies a methodological framework that can be tailored to suit a variety of marine organisms with a range of life-history characteristics.
Against the odds: Complete outcrossing in a monoecious clonal seagrass Posidonia australis (Posidoniaceae)
Publisher: Oxford University Press (OUP)
Date: 07-05-2014
DOI: 10.1093/AOB/MCU048
Identifying critical recruitment bottlenecks limiting seedling establishment in a degraded seagrass ecosystem
Publisher: Springer Science and Business Media LLC
Date: 11-2017
DOI: 10.1038/S41598-017-13833-Y
Abstract: Identifying early life-stage transitions limiting seagrass recruitment could improve our ability to target demographic processes most responsive to management. Here we determine the magnitude of life-stage transitions along gradients in physical disturbance limiting seedling establishment for the marine angiosperm, Posidonia australis . Transition matrix models and sensitivity analyses were used to identify which transitions were critical for successful seedling establishment during the first year of seed recruitment and projection models were used to predict the most appropriate environments and seeding densities. Total survival probability of seedlings was low (0.001), however, transition probabilities between life-stages differed across the environmental gradients seedling recruitment was affected by grazing and bioturbation prevailing during the first life-stage transition (1 month), and 4–6 months later during the third life-stage transition when establishing seedlings are physically removed by winter storms. Models projecting population growth from different starting seed densities showed that seeds could replace other more labour intensive and costly methods, such as transplanting adult shoots, if disturbances are moderated sufficiently and if large numbers of seed can be collected in sufficient quantity and delivered to restoration sites efficiently. These outcomes suggest that by improving management of early demographic processes, we could increase recruitment in restoration programs.
The Risk of Multiple Anthropogenic and Climate Change Threats Must Be Considered for Continental Scale Conservation and Management of Seagrass Habitat
Publisher: Frontiers Media SA
Date: 22-03-2022
DOI: 10.3389/FMARS.2022.837259
Abstract: Globally marine-terrestrial interfaces are highly impacted due to a range of human pressures. Seagrass habitats exist in the shallow marine waters of this interface, have significant values and are impacted by a range of pressures. Cumulative risk analysis is widely used to identify risk from multiple threats and assist in prioritizing management actions. This study conducted a cumulative risk analysis of seagrass habitat associated with the Australian continent to support management actions. We developed a spatially explicit risk model based on a database of threats to coastal aquatic habitat in Australia, spanning 35,000 km of coastline. Risk hotspots were identified using the model and reducing the risk of nutrient and sediment pollution for seagrass habitat was assessed. Incorporating future threats greatly altered the spatial-distribution of risk. High risk from multiple current threats was identified throughout all bioregions, but high risk from climate change alone manifested in only two. Improving management of nutrient and sediment loads, a common approach to conserve seagrass habitat did reduce risk, but only in temperate regions, highlighting the danger of focusing management on a single strategy. Monitoring, management and conservation actions from a national and regional perspective can be guided by these outputs.
Reconstruction of centennial-scale fluxes of chemical elements in the Australian coastal environment using seagrass archives
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.SCITOTENV.2015.09.017
Abstract: The study of a Posidonia australis sedimentary archive has provided a record of changes in element concentrations (Al, Fe, Mn, Pb, Zn, Cr, Cd, Co, As, Cu, Ni and S) over the last 3000 years in the Australian marine environment. Human-derived contamination in Oyster Harbor (SW Australia) started ~100 years ago (AD ~1900) and exponentially increased until present. This appears to be related to European colonization of Australia and the subsequent impact of human activities, namely mining, coal and metal production, and extensive agriculture. Two contamination periods of different magnitude have been identified: Expansion period (EXP, AD ~1900-1970) and Establishment period (EST, AD ~1970 to present). Enrichments of chemical elements with respect to baseline concentrations (in s les older than ~115 cal years BP) were found for all elements studied in both periods, except for Ni, As and S. The highest enrichment factors were obtained for the EST period (ranging from 1.3-fold increase in Cu to 7.2-fold in Zn concentrations) compared to the EXP period (1.1-fold increase for Cu and Cr to 2.4-fold increase for Pb). Zinc, Pb, Mn and Co concentrations during both periods were 2- to 7-fold higher than baseline levels. This study demonstrates the value of Posidonia mats as long-term archives of element concentrations and trends in coastal ecosystems. We also provide preliminary evidence on the potential for Posidonia meadows to act as significant long-term biogeochemical sinks of chemical elements.
Mapping the Marine Environment Through a Cross-Cultural Collaboration
Publisher: Frontiers Media SA
Date: 27-08-2020
Modelling formation of complex topography by the seagrass Posidonia oceanica
Publisher: Elsevier BV
Date: 12-2005
Effects of dredging on critical ecological processes for marine invertebrates, seagrasses and macroalgae, and the potential for management with environmental windows using Western Australia as a case study
Publisher: Elsevier BV
Date: 07-2017
Deep thinking
Publisher: Oxford University Press (OUP)
Date: 26-05-2017
Abstract: Mesophotic coral ecosystems (MCEs) occur at depths beyond those typically associated with coral reefs. Significant logistical challenges associated with data collection in deep water have resulted in a limited understanding of the ecological relevance of these deeper coral ecosystems. We review the trends in this research, covering the geographic spread of MCE research, the focus of these studies, the methods used, how MCEs differ in terms of species ersity and begin to assess connectivity of coral populations. Clear locational biases were observed, with studies concentrated in a few discrete areas mainly around the Atlantic region. The focus of MCE studies has ersified in recent years and more detailed aspects of MCE ecology are now being investigated in particular areas of research. Advances in technology are also reflected in the current range of research, with a wider variety of methods now employed. However, large information gaps are present in entire regions and particularly in relation to the threats, impacts and subsequent management of MCEs. Analysis of species ersity shows that initial definitions based on depth alone may not be appropriate globally, while further taxonomic resolution may also be required to deduce the full bio ersity of major groups in certain regions. Genetic studies to date show species-specific results, although distinct deeper populations do appear to exist, which raises questions regarding the potential of MCEs to act as refugia.
A comparison of underwater visual distance estimates made by scuba divers and a stereo-video system: implications for underwater visual census of reef fish abundance
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/MF03130
Abstract: Underwater visual census of reef fish by scuba ers is a widely used and useful technique for assessing the composition and abundance of reef fish assemblages, but suffers from several biases and errors. We compare the accuracy of underwater visual estimates of distance made by novice and experienced scientific ers and an underwater stereo-video system. We demonstrate the potential implications that distance errors may have on underwater visual census assessments of reef fish abundance. We also investigate how the accuracy and precision of scuba er length estimates of fish is affected as distance increases. Distance was underestimated by both experienced (mean relative error = −11.7%, s.d. = 21.4%) and novice scientific ers (mean relative error = −5.0%, s.d. = 17.9%). For experienced scientific ers this error may potentially result in an 82% underestimate or 194% overestimate of the actual area censused, which will affect estimates of fish density. The stereo-video system also underestimated distance but to a much lesser degree (mean relative error = −0.9%, s.d. = 2.6%) and with less variability than the ers. There was no correlation between the relative error of length estimates and the distance of the fish away from the observer.
Differences in fish assemblages from different reef habitats at Hamelin Bay, south-western Australia
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/MF02040
Abstract: Differences in the ersity of fish species between granite and limestone reefs, as well as high- and low-relief limestone reefs, were investigated at Hamelin Bay, south-western Australia. It was found that there were significant differences in the presence and abundance of fish species between granite reefs and limestone reefs. Granite reefs were characterized by greater numbers of Coris auricularis (western king wrasse) and Parma mccullochi (common scalyfin), whereas limestone reefs had greater numbers of the fish species Odax cyanomelas (herring cale), Pempheris klunzingeri (rough bullseye) and Kyphosus sydneyanus (common buffalo bream). A significant difference in fish ersity was also found between high-relief and low-relief limestone reefs in the same area. More species were found on the high-relief reefs than low-relief reefs. Complementing differences in fish assemblages, significant differences were found in algal assemblages from the different habitats. This was mainly owing to a dominance of Ecklonia radiata on low-relief limestone reefs. Ecklonia radiata was less dominant on granite reefs and on high-relief limestone reefs, where there was a lower overall algal biomass and a higher total number of species.
Multi-scale spatial patterns of three seagrass species with different growth dynamics
Publisher: Wiley
Date: 28-03-2008
Description of a Remote Still Photography System for Collection of Benthic Photo-Quadrats
Publisher: Marine Technology Society
Date: 03-2010
DOI: 10.4031/MTSJ.44.2.1
Abstract: Abstract Quantitative s ling of benthic communities is central to a wide range of ecological research, from understanding spatial distribution and ecology to impact studies. With the need to s le deep as well as shallow regions, limited s ling capabilities of er-based methods and the expanding footprint of human activity, there is a need for an effective system capable of classifying benthic assemblages and able to monitor potential anthropogenic impacts. Here we describe a remote system capable of collecting benthic photo-quadrats to depths of 100 m. A procedure for the classification of these images into 64 abiotic and biotic categories is also described. During a 64-day s ling program that included s ling at seven locations along 1,200 km of coastline that resulted in the collection of over 9,000 images, only one day of s ling was lost due to equipment malfunction, with 99.5% of points able to be classified to the taxonomic resolution required, demonstrating the reliability and accuracy of this system. Furthermore, the incorporation of differential GPS and ultra-short baseline positioning system allowed collected images to be geo-referenced to within 0.5 m. Such precision allows the system to be used in conjunction with hydroacoustic habitat mapping techniques and potentially for repeated monitoring of areas with a small spatial extent. Development of this system provides a cost-effective means of quantifying benthic assemblages over broad scales.
Decreasing resilience of kelp beds along a latitudinal temperature gradient: potential implications for a warmer future
Publisher: Wiley
Date: 18-05-2010
DOI: 10.1111/J.1461-0248.2010.01466.X
Abstract: Successful mitigation of negative effects of global warming will depend on understanding the link between physiological and ecological responses of key species. We show that while metabolic adjustment may assist Australasian kelp beds to persist and maintain abundance in warmer waters, it also reduces the physiological responsiveness of kelps to perturbation, and suppresses canopy recovery from disturbances by reducing the ecological performance of kelp recruits. This provides a warning not to rely solely on inventories of distribution and abundance to evaluate ecosystem function. The erosion of resilience is mediated by a shift in adult-juvenile interactions from competitive under cool to facilitative under warm conditions, supporting the prediction that positive interactions may become increasingly important in a warmer future. Kelp beds may remain intact but with a lower threshold for where additional impacts (e.g., extreme storms or reduced water quality) will lead to persistent loss of habitat and ecological function.
Nonlinear processes in seagrass colonisation explained by simple clonal growth rules
Publisher: Wiley
Date: 07-12-2005
Predation on Posidonia australis seeds in seagrass habitats of Rottnest Island, Western Australia: patterns and predators
Publisher: Inter-Research Science Center
Date: 11-05-2006
DOI: 10.3354/MEPS313105
Optimizing the restoration of the threatened seagrass Posidonia australis
Publisher: Wiley
Date: 14-03-2023
DOI: 10.1111/REC.13893
Abstract: Restoration is an important activity to assist the recovery of damaged or degraded ecosystems. Accessing healthy donor material can be challenging when restoring threatened ecological communities, but careful selection of donor material may improve the success and cost‐effectiveness of restoration projects. We aim to optimize restoration of the threatened seagrass Posidonia australis by identifying the traits of donor material that best predict survival and establishment. To avoid collecting donor material from threatened populations, a recent restoration method focuses on using naturally detached fragments of P. australis collected from the shoreline, which are stored in outdoor tanks prior to planting. Here, we examine 10 morphological traits of P. australis fragments and other variables relating to collection method to identify which traits best predicted survival after replanting. Fragments with more shoots and less dead tissue (necrosis) in their leaves had higher survival 1 year after planting. Fragments that were stored longer in tanks prior to replanting had significantly higher survival rates. These results can refine the selection for donor material used in restoration and optimize the recently developed restoration technique for P. australis using beach‐cast seagrass material.
Impact of mooring activities on carbon stocks in seagrass meadows
Publisher: Springer Science and Business Media LLC
Date: 16-03-2016
DOI: 10.1038/SREP23193
Abstract: Boating activities are one of the causes that threaten seagrass meadows and the ecosystem services they provide. Mechanical destruction of seagrass habitats may also trigger the erosion of sedimentary organic carbon (C org ) stocks, which may contribute to increasing atmospheric CO 2 . This study presents the first estimates of loss of C org stocks in seagrass meadows due to mooring activities in Rottnest Island, Western Australia. Sediment cores were s led from seagrass meadows and from bare but previously vegetated sediments underneath moorings. The C org stores have been compromised by the mooring deployment from 1930s onwards, which involved both the erosion of existing sedimentary C org stores and the lack of further accumulation of C org . On average, undisturbed meadows had accumulated ~6.4 Kg C org m −2 in the upper 50 cm-thick deposits at a rate of 34 g C org m −2 yr −1 . The comparison of C org stores between meadows and mooring scars allows us to estimate a loss of 4.8 kg C org m −2 in the 50 cm-thick deposits accumulated over ca. 200 yr as a result of mooring deployments. These results provide key data for the implementation of C org storage credit offset policies to avoid the conversion of seagrass ecosystems and contribute to their preservation.
Re-evaluating species boundaries among members of the Posidonia ostenfeldii species complex (Posidoniaceae) - morphological and genetic variation.
Publisher: Elsevier BV
Date: 2000
Changes in seagrass coverage in Cockburn Sound, Western Australia between 1967 and 1999
Publisher: Elsevier BV
Date: 05-2002
Short-term Responses of Posidonia australis to Changes in Light Quality
Publisher: Frontiers Media SA
Date: 17-01-2018
The market for sustainable seafood drives transformative change in fishery social-ecological systems
Publisher: Elsevier BV
Date: 07-2019
Upgrading Marine Ecosystem Restoration Using Ecological‐Social Concepts
Publisher: Oxford University Press (OUP)
Date: 16-12-2015
Nutrient dynamics in two seagrass species, Posidonia coriacea and Zostera tasmanica, on Success Bank, Western Australia
Publisher: Elsevier BV
Date: 06-2004
Marine heatwave and reduced light scenarios cause species‐specific metabolomic changes in seagrasses under ocean warming
Publisher: Wiley
Date: 25-06-2023
DOI: 10.1111/NPH.19092
Abstract: Climate change and extreme climatic events, such as marine heatwaves (MHWs), are threatening seagrass ecosystems. Metabolomics can be used to gain insight into early stress responses in seagrasses and help to develop targeted management and conservation measures. We used metabolomics to understand the temporal and mechanistic response of leaf metabolism in seagrasses to climate change. Two species, temperate Posidonia australis and tropical Halodule uninervis , were exposed to a combination of future warming, simulated MHW with subsequent recovery period, and light deprivation in a mesocosm experiment. The leaf metabolome of P. australis was altered under MHW exposure at ambient light while H. uninervis was unaffected. Light deprivation impacted both seagrasses, with combined effects of heat and low light causing greater alterations in leaf metabolism . There was no MHW recovery in P. australis . Conversely, the heat‐resistant leaf metabolome of H. uninervis showed recovery of sugars and intermediates of the tricarboxylic acid cycle under combined heat and low light exposure, suggesting adaptive strategies to long‐term light deprivation. Overall, this research highlights how metabolomics can be used to study the metabolic pathways of seagrasses, identifies early indicators of environmental stress and analyses the effects of environmental factors on plant metabolism and health.
Shifts in composition of microbial communities of subtidal sandy sediments maximise retention of nutrients
Publisher: Oxford University Press (OUP)
Date: 04-09-2012
DOI: 10.1111/J.1574-6941.2012.01472.X
Abstract: The density and composition of microbial communities of subtidal sandy sediments determines their role in the cycling of nutrients in coastal waters. It has previously been found that sediments disturbed by waves and currents have reduced biomass, greater productivity to respiration (P/R) ratios and a tendency to take up nutrients. Conversely, with shelter and greater biomass, P/R ratios were smaller and nutrients released. This study, in warm temperate waters, examined the consequences of high and low levels of hydrodynamic energy on the microbial community structure and biogeochemistry at two locations at different times of year. Measurements included biomarkers, sediment properties and exchanges of gases and nutrients. Microbial communities were dominated by diatoms and bacteria. Exposed sites, relative to paired sheltered sites, had smaller ratios of bacteria to benthic microalgae (BMA), larger C/N ratios, smaller indices of diagenetic activity, but smaller P/R ratios. The bacteria in exposed sediments exhibited biomass-normalised rates of respiration almost double those in sheltered sediments. This increased activity was most likely fuelled by elevated concentrations of photosynthates, secreted by BMA attached to sand grains. Changes in community composition owing to different levels of disturbance led to shifts in functioning that resulted in consistently small exchanges of nutrients.
In situ oxygen dynamics in rhizomes of the seagrass Posidonia sinuosa
Publisher: Inter-Research Science Center
Date: 12-03-2018
DOI: 10.3354/MEPS12477
Climate-driven regime shift of a temperate marine ecosystem
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-07-2016
Abstract: Ecosystems over time have endured much disturbance, yet they tend to remain intact, a characteristic we call resilience. Though many systems have been lost and destroyed, for systems that remain physically intact, there is debate as to whether changing temperatures will result in shifts or collapses. Wernburg et al. show that extreme warming of a temperate kelp forest off Australia resulted not only in its collapse, but also in a shift in community composition that brought about an increase in herbivorous tropical fishes that prevent the reestablishment of kelp. Thus, many systems may not be resilient to the rapid climate change that we face. Science , this issue p. 169
Impact of seagrass loss and subsequent revegetation on carbon sequestration and stocks
Publisher: Wiley
Date: 09-02-2015
Posidonia australis seed predation in seagrass habitats of Two Peoples Bay, Western Australia
Publisher: Elsevier BV
Date: 2007
Aquaculture of Posidonia australis Seedlings for Seagrass Restoration Programs: Effect of Sediment Type and Organic Enrichment on Growth
Publisher: Wiley
Date: 05-07-2012
Clonality in seagrasses, emergent properties and seagrass landscapes
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/MEPS290291
Teleost community composition and the role of herbivory on the intertidal reef of a small isolated island in north-west Australia
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/MF19066
Abstract: Most of the world’s tropical coastal and shelf areas are heavily affected by anthropogenic activities, but the north-west shelf of Australia is considered a ‘very low-impact’ area. The role of herbivory on coral reefs is recognised, but most of that research comes from reefs with considerable land-based impacts. In this study we s led the teleost community and evaluated herbivory on the reef platform at Browse Island, a small isolated island 200km off north-western Australia, using several approaches: (1) tethering of macroalgae (2) herbivore exclosures and (3) video footage. In total, 99 teleost species from 26 families were identified. Turf algal consumption was evident and 18 teleost turf consumers were identified. In contrast, no evidence was found of herbivory on large macroalgae, and browsers, the only group able to consume macroalgae, were represented by just four species all belonging to the genus Naso. The lack of ersity among these specialist herbivores may be a consequence of the small surface area of the reef and the distance to other emergent reefs. Based on a model of top-down control of macroalgae, the reef is potentially vulnerable to disturbance. Small isolated reefs can have low resilience despite having low impacts from land.
Seagrass Restoration Is Possible: Insights and Lessons From Australia and New Zealand
Publisher: Frontiers Media SA
Date: 14-08-2020
Effects of desalination brine and seawater with the same elevated salinity on growth, physiology and seedling development of the seagrass Posidonia australis
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.MARPOLBUL.2019.02.001
Abstract: Desalination has the potential to provide an important source of potable water to growing coastal populations but it also produces highly saline brines with chemical additives, posing a possible threat to benthic marine communities. The effects of brine (0%, 50%, 100%) were compared to seawater treatments with the same salinity (37, 46, 54 psu) for seagrass (Posidonia australis) in mesocosms over 2 weeks. There were significant differences between brine and salinity treatments for photosynthesis, water relations and growth. Germinating seedlings of P. australis were also tested in brine treatments (0%, 25%, 50%, 100%) over 7 weeks followed by 2.5 weeks recovery in seawater. Growth was severely inhibited only in 100% brine. These experiments demonstrated that brine increased the speed and symptoms of stress in adult plants compared to treatments with the same salinity, whereas seedlings tolerated far longer brine exposure, and so could potentially contribute to seagrass recovery through recruitment.
Austral spring microalgae across the Weddell Sea ice edge: spatial relationships found along a northward transect during AMERIEZ 83
Publisher: Elsevier BV
Date: 1988
Impact of Marine Heatwaves on Seagrass Ecosystems
Publisher: Springer International Publishing
Date: 2021
Microsites play an important role for seedling survival in the seagrass Amphibolis antarctica
Publisher: Elsevier BV
Date: 05-2011
Sponges in shallow tropical and temperate reefs are important habitats for marine invertebrate biodiversity
Publisher: Springer Science and Business Media LLC
Date: 14-10-2020
Can mud (silt and clay) concentration be used to predict soil organic carbon content within seagrass ecosystems?
Publisher: Copernicus GmbH
Date: 07-09-2016
Abstract: Abstract. The emerging field of blue carbon science is seeking cost-effective ways to estimate the organic carbon content of soils that are bound by coastal vegetated ecosystems. Organic carbon (Corg) content in terrestrial soils and marine sediments has been correlated with mud content (i.e., silt and clay, particle sizes 63 µm), however, empirical tests of this theory are lacking for coastal vegetated ecosystems. Here, we compiled data (n = 1345) on the relationship between Corg and mud contents in seagrass ecosystems (79 cores) and adjacent bare sediments (21 cores) to address whether mud can be used to predict soil Corg content. We also combined these data with the δ13C signatures of the soil Corg to understand the sources of Corg stores. The results showed that mud is positively correlated with soil Corg content only when the contribution of seagrass-derived Corg to the sedimentary Corg pool is relatively low, such as in small and fast-growing meadows of the genera Zostera, Halodule and Halophila, and in bare sediments adjacent to seagrass ecosystems. In large and long-living seagrass meadows of the genera Posidonia and Amphibolis there was a lack of, or poor relationship between mud and soil Corg content, related to a higher contribution of seagrass-derived Corg to the sedimentary Corg pool in these meadows. The relatively high soil Corg contents with relatively low mud contents (e.g., mud-Corg saturation) in bare sediments and Zostera, Halodule and Halophila meadows was related to significant allochthonous inputs of terrestrial organic matter, while higher contribution of seagrass detritus in Amphibolis and Posidonia meadows disrupted the correlation expected between soil Corg and mud contents. This study shows that mud is not a universal proxy for blue carbon content in seagrass ecosystems, and therefore should not be applied generally across all seagrass habitats. Mud content can only be used as a proxy to estimate soil Corg content for scaling up purposes when opportunistic and/or low biomass seagrass species (i.e., Zostera, Halodule and Halophila) are present (explaining 34 to 91 % of variability), and in bare sediments (explaining 78 % of the variability). The results obtained could enable robust scaling up exercises at a low cost as part of blue carbon stock assessments.
Can single classifiers be as useful as model ensembles to produce benthic seabed substratum maps?
Publisher: Elsevier BV
Date: 05-2018
Oxygen loss from seagrass roots coincides with colonisation of sulphide-oxidising cable bacteria and reduces sulphide stress
Publisher: Springer Science and Business Media LLC
Date: 23-10-2019
Underwater video as a monitoring tool to detect change in seagrass cover
Publisher: Elsevier BV
Date: 07-2006
DOI: 10.1016/J.JENVMAN.2005.08.021
Abstract: To date seagrass monitoring has involved the removal of seagrass from its environment. In fragile or highly disturbed systems, monitoring using destructive techniques may interfere with the environment or add to the burden of disturbance. Video photography is a form of non-destructive monitoring that does not require the removal of seagrass or interference with the environment and has the potential to be a valuable tool in monitoring seagrass systems. This study investigated the efficacy of video photography as a tool for detecting change in seagrass cover, using the temperate Australian species Amphibolis antarctica (Labill.) Sonder ex Aschers. Using visual and random point estimates of seagrass cover from video footage, it was possible to determine the minimum s le size (number of random video frames) needed to detect change in seagrass cover, the minimum detectable change in cover and the probability of the monitoring design committing a Type II error. Video footage was examined at three scales: transects (m apart), sites (km apart) and regions (tens of km apart). Using visual and random point estimation techniques, a minimum s le size of ten quadrats per transect was required to detect change in uniform and variable seagrass cover. With ten quadrats it was possible to identify a minimum detectable change in cover of 15% for uniform and 30% for variable seagrass cover. Power analysis was used to determine the probability of committing a Type II error from the data. Region level data had low power, corresponding to a high risk of committing a Type II error. Site and transect level data had high power corresponding to a low risk of committing a Type II error. Based on this study's data, managers using video to monitor for change in seagrass cover are advised to use data from the smaller scale, for ex le, site and transect level data. By using data from the smaller scale, managers will have a low risk of incorrectly concluding there has not been a disturbance when one has actually occurred.
First report of hybridization in the seagrass genus Posidonia (Posidoniaceae)
Publisher: Elsevier BV
Date: 06-2019
Modification of the physical environment by an Ecklonia radiata (Laminariales) canopy and implications for associated foliose algae
Publisher: Springer Science and Business Media LLC
Date: 26-10-2005
Seagrass Halophila ovalis is affected by light quality across different life history stages
Publisher: Inter-Research Science Center
Date: 31-05-2017
DOI: 10.3354/MEPS12105
Direct measurements of root growth and productivity in the seagrasses Posidonia australis and P. sinuosa
Publisher: Wiley
Date: 2011
Restricted gene flow and local adaptation highlight the vulnerability of high-latitude reefs to rapid environmental change
Publisher: Wiley
Date: 03-03-2017
DOI: 10.1111/GCB.13639
Abstract: Global climate change poses a serious threat to the future health of coral reef ecosystems. This calls for management strategies that are focused on maximizing the evolutionary potential of coral reefs. Fundamental to this is an accurate understanding of the spatial genetic structure in dominant reef-building coral species. In this study, we apply a genotyping-by-sequencing approach to investigate genome-wide patterns of genetic ersity, gene flow, and local adaptation in a reef-building coral, Pocillopora damicornis, across 10 degrees of latitude and a transition from temperate to tropical waters. We identified strong patterns of differentiation and reduced genetic ersity in high-latitude populations. In addition, genome-wide scans for selection identified a number of outlier loci putatively under directional selection with homology to proteins previously known to be involved in heat tolerance in corals and associated with processes such as photoprotection, protein degradation, and immunity. This study provides genomic evidence for both restricted gene flow and local adaptation in a widely distributed coral species, and highlights the potential vulnerability of leading-edge populations to rapid environmental change as they are locally adapted, reproductively isolated, and have reduced levels of genetic ersity.
Invasion Is a Community Affair: Clandestine Followers in the Bacterial Community Associated to Green Algae, Caulerpa racemosa, Track the Invasion Source
Publisher: Public Library of Science (PLoS)
Date: 16-07-2013
Exploring Symbiodinium diversity and host specificity in Acropora corals from geographical extremes of Western Australia with 454 amplicon pyrosequencing
Publisher: Wiley
Date: 06-2014
DOI: 10.1111/MEC.12801
Abstract: Scleractinian corals have demonstrated the ability to shuffle their endosymbiotic dinoflagellate communities (genus Symbiodinium) during periods of acute environmental stress. This has been proposed as a mechanism of acclimation, which would be increased by a erse and flexible association with Symbiodinium. Conventional molecular techniques used to evaluate Symbiodinium ersity are unable to identify genetic lineages present at background levels below 10%. Next generation sequencing (NGS) offers a solution to this problem and can resolve microorganism ersity at much finer scales. Here we apply NGS to evaluate Symbiodinium ersity and host specificity in Acropora corals from contrasting regions of Western Australia. The application of 454 pyrosequencing allowed for detection of Symbiodinium operational taxonomic units (OTUs) occurring at frequencies as low as 0.001%, offering a 10,000-fold increase in sensitivity compared to traditional methods. All coral species from both regions were overwhelmingly dominated by a single clade C OTU (accounting for 98% of all recovered sequences). Only 8.5% of colonies associated with multiple clades (clades C and D, or C and G), suggesting a high level of symbiont specificity in Acropora assemblages in Western Australia. While only 40% of the OTUs were shared between regions, the dominance of a single OTU resulted in no significant difference in Symbiodinium community structure, demonstrating that the coral-algal symbiosis can remain stable across more than 15° of latitude and a range of sea surface temperature profiles. This study validates the use of NGS platforms as tools for providing fine-scale estimates of Symbiodinium ersity and can offer critical insight into the flexibility of the coral-algal symbiosis.
Disturbance and reef topography maintain high local diversity in Ecklonia radiata kelp forests
Publisher: Wiley
Date: 10-2007
DOI: 10.1111/J.0030-1299.2007.15689.X
Abstract: Disturbance of competitive‐dominant plant and algae canopies often lead to increased ersity of the assemblage. Kelp forests, particularly those of temperate Western Australia, are habitats with high alpha ersity. This study investigated the roles of broad‐scale canopy loss and local scale reef topography on structuring the kelp‐dominated macroalgal forests in Western Australia. Eighteen 314 m 2 circular areas were cleared of their Ecklonia radiata canopy and eighteen controls were established across three locations. The patterns of macroalgal recolonisation in replicate clearances were observed over a 34 month period. Macroalgal species richness initially increased after canopy removal with a turf of filamentous and foliose macroalgae dominating cleared areas for up to seven months. A dense Sargassum canopy dominated cleared areas from 11 to 22 months. By 34 months, partial recovery of the kelp canopy into cleared areas had occurred. Some cleared areas did not follow this trajectory but remained dominated by turfing, foliose and filamentous algae. As kelp canopies developed, the initial high species ersity declined but still remained elevated relative to undisturbed controls, even after 34 months. More complex reef topography was associated with greater variability in the algal assemblage between replicate quadrats suggesting colonising algae had a greater choice of microhabitats available to them on topographically complex reefs. Shading by canopies of either Sargassum spp. and E. radiata are proposed to highly influence the abundance of algae through competitive exclusion that is relaxed by disturbance of the canopy. Disturbance of the canopy in E. radiata kelp forests created a mosaic of different patch types (turf, Sargassum ‐dominated, kelp‐dominated). These patch types were both transient and stable over the 34 months of this study, and are a potential contemporary process that maintains high species ersity in temperate kelp‐dominated reefs.
Australian vegetated coastal ecosystems as global hotspots for climate change mitigation
Publisher: Springer Science and Business Media LLC
Date: 02-10-2019
DOI: 10.1038/S41467-019-12176-8
Abstract: Policies aiming to preserve vegetated coastal ecosystems (VCE tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO 2 emission benefits of VCE conservation and restoration. Australia contributes 5–11% of the C stored in VCE globally (70–185 Tg C in aboveground biomass, and 1,055–1,540 Tg C in the upper 1 m of soils). Potential CO 2 emissions from current VCE losses are estimated at 2.1–3.1 Tg CO 2 -e yr -1 , increasing annual CO 2 emissions from land use change in Australia by 12–21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions.
Marine sponges of the Dampier Archipelago, Western Australia: patterns of species distributions, abundance and diversity
Publisher: Springer Science and Business Media LLC
Date: 26-05-2006
Protection from fishing alters the species composition of fish assemblages in a temperate-tropical transition zone
Publisher: Springer Science and Business Media LLC
Date: 21-07-2007
Naturally-detached fragments of the endangered seagrass Posidonia australis collected by citizen scientists can be used to successfully restore fragmented meadows
Publisher: Elsevier BV
Date: 10-2021
Temperate territorial damselfish act like tropical damselfish, but have no measurable effect on algae within their feeding areas
Publisher: Elsevier BV
Date: 11-2015
Composition of Seagrass Root Associated Bacterial Communities Are Linked to Nutrients and Heavy Metal Concentrations in an Anthropogenically Influenced Estuary
Publisher: Frontiers Media SA
Date: 27-01-2022
DOI: 10.3389/FMARS.2021.768864
Abstract: Seagrasses are globally recognized as bioindicators of marine eutrophication and contamination. Seagrasses also harbor a distinct root microbial community that largely reflects the conditions of the surrounding environment as well as the condition of the seagrass. Hence monitoring changes in the root microbial community could act as an additional biological indicator that reflects both the seagrass health condition, as well as potential deterioration in coastal waters. We used 16S rRNA gene sequencing combined with analysis of seagrass nutrients (C, N, δ 15 N, δ 13 C) and tissue metal concentrations to investigate potential links between seagrass ( Halophila ovalis ) root bacteria and seagrass nutrient and metal concentrations within an anthropogenically influenced estuary. We found seagrass tissue nitrogen (%) and δ 15 N values were 2–5 times higher than global averages for this species. Seagrass root associated bacteria formed distinct communities that clustered by site and were correlated to both seagrass nutrient and metal concentration, with some putative sulfide oxidizing bacteria ( Sulfurimonas and Sulfurovum ) correlated with greater nutrient concentrations, and putative iron cycling bacteria ( Lewinella and Woeseia ) correlated with greater Fe and As concentrations. Our findings shed further light on the relationship between seagrass and their microbes, as well as provide additional assessment of the use of both seagrass and their microbes as indicators of estuarine and seagrass condition.
AUV-based classification of benthic communities of the Ningaloo shelf and mesophotic areas
Publisher: Springer Science and Business Media LLC
Date: 28-05-2018
Coral classification with hybrid feature representations
Publisher: IEEE
Date: 09-2012
Key attributes related to fishery improvement project (FIP) effectiveness in promoting improvements towards sustainability
Publisher: Wiley
Date: 13-03-2019
DOI: 10.1111/FAF.12357
Seagrass losses since mid‐20th century fuelled CO2 emissions from soil carbon stocks
Publisher: Wiley
Date: 07-07-2020
DOI: 10.1111/GCB.15204
The Central Role of Dispersal in the Maintenance and Persistence of Seagrass Populations
Publisher: Oxford University Press (OUP)
Date: 10-2019
Nesting behaviour of a temperate damselfish (Parma mccullochi) and its influence on algae
Publisher: Informa UK Limited
Date: 05-2013
Using Agent-Based models to aid reef restoration: Enhancing Coral cover and topographic complexity through the spatial arrangement of coral transplants
Publisher: Wiley
Date: 21-11-2005
Crustose coralline algal growth, calcification and mortality following a marine heatwave in Western Australia
Publisher: Elsevier BV
Date: 09-2015
Interannual and small-scale spatial variability in sexual reproduction of the seagrasses Posidonia coriacea and Heterozostera tasmanica, southwestern Australia
Publisher: Elsevier BV
Date: 12-2002
Evolutionary history of the seagrass genus Posidonia
Publisher: Inter-Research Science Center
Date: 17-01-2011
DOI: 10.3354/MEPS08879
The effects of thallus size, life stage, aggregation, wave exposure and substratum conditions on the forces required to break or dislodge the small kelp Ecklonia radiata
Publisher: Walter de Gruyter GmbH
Date: 2004
DOI: 10.1515/BOT.2004.068
Trophic Transfers from Seagrass Meadows Subsidize Diverse Marine and Terrestrial Consumers
Publisher: Springer Science and Business Media LLC
Date: 23-09-2008
Accelerating Tropicalization and the Transformation of Temperate Seagrass Meadows
Publisher: Oxford University Press (OUP)
Date: 14-09-2016
Landscape-scale changes in seagrass distribution over time: a case study from Success Bank, Western Australia.
Publisher: Elsevier BV
Date: 11-1999
Modelling seagrass growth and development to evaluate transplanting strategies for restoration
Publisher: Oxford University Press (OUP)
Date: 05-08-2011
DOI: 10.1093/AOB/MCR131
Factors influencing distribution and habitat associations in an endemic group of temperate Western Australian reef fishes over a latitudinal gradient
Publisher: Inter-Research Science Center
Date: 15-12-2014
DOI: 10.3354/MEPS11000
Demographic and genetic connectivity: the role and consequences of reproduction, dispersal and recruitment in seagrasses
Publisher: Wiley
Date: 23-03-2017
DOI: 10.1111/BRV.12261
Abstract: Accurate estimation of connectivity among populations is fundamental for determining the drivers of population resilience, genetic ersity, adaptation and speciation. However the separation and quantification of contemporary versus historical connectivity remains a major challenge. This review focuses on marine angiosperms, seagrasses, that are fundamental to the health and productivity of temperate and tropical coastal marine environments globally. Our objective is to understand better the role of sexual reproduction and recruitment in influencing demographic and genetic connectivity among seagrass populations through an integrated multidisciplinary assessment of our present ecological, genetic, and demographic understanding, with hydrodynamic modelling of transport. We investigate (i) the demographic consequences of sexual reproduction, dispersal and recruitment in seagrasses, (ii) contemporary transport of seagrass pollen, fruits and seed, and vegetative fragments with a focus on hydrodynamic and particle transport models, and (iii) contemporary genetic connectivity among seagrass meadows as inferred through the application of genetic markers. New approaches are reviewed, followed by a summary outlining future directions for research: integrating seascape genetic approaches incorporating hydrodynamic modelling for dispersal of pollen, seeds and vegetative fragments integrating studies across broader geographic ranges and incorporating non-equilibrium modelling. These approaches will lead to a more integrated understanding of the role of contemporary dispersal and recruitment in the persistence and evolution of seagrasses.
Large-scale geographic variation in distribution and abundance of Australian deep-water kelp forests
Publisher: Public Library of Science (PLoS)
Date: 18-02-2015
High Sulfide Intrusion in Five Temperate Seagrasses Growing Under Contrasting Sediment Conditions
Publisher: Springer Science and Business Media LLC
Date: 06-09-2013
Reproductive Output, Synchrony across Depth and Influence of Source Depth in the Development of Early Life stages of Kelp
Publisher: Wiley
Date: 18-12-2021
DOI: 10.1111/JPY.13095
Automatic Hierarchical Classification of Kelps Using Deep Residual Features
Publisher: MDPI AG
Date: 13-01-2020
DOI: 10.3390/S20020447
Abstract: Across the globe, remote image data is rapidly being collected for the assessment of benthic communities from shallow to extremely deep waters on continental slopes to the abyssal seas. Exploiting this data is presently limited by the time it takes for experts to identify organisms found in these images. With this limitation in mind, a large effort has been made globally to introduce automation and machine learning algorithms to accelerate both classification and assessment of marine benthic biota. One major issue lies with organisms that move with swell and currents, such as kelps. This paper presents an automatic hierarchical classification method local binary classification as opposed to the conventional flat classification to classify kelps in images collected by autonomous underwater vehicles. The proposed kelp classification approach exploits learned feature representations extracted from deep residual networks. We show that these generic features outperform the traditional off-the-shelf CNN features and the conventional hand-crafted features. Experiments also demonstrate that the hierarchical classification method outperforms the traditional parallel multi-class classifications by a significant margin (90.0% vs. 57.6% and 77.2% vs. 59.0%) on Benthoz15 and Rottnest datasets respectively. Furthermore, we compare different hierarchical classification approaches and experimentally show that the sibling hierarchical training approach outperforms the inclusive hierarchical approach by a significant margin. We also report an application of our proposed method to study the change in kelp cover over time for annually repeated AUV surveys.
Measuring fragmentation of seagrass landscapes: Which indices are most appropriate for detecting change?
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/MF04300
Abstract: Many indices are available for assessment of spatial patterns in landscape ecology, yet there is presently no consensus about which ones effectively quantify habitat fragmentation. Research that has been carried out to date has evaluated indices primarily using computer-simulated models of terrestrial environments, but how they perform when applied to real landscapes, particularly in the marine environment, has received little attention. Eleven indices that are commonly used for quantifying habitat fragmentation were assessed for their abilities to measure different levels of fragmentation in 16-ha landscape windows of mapped seagrass. The landscape windows were grouped into five categories, from highly fragmented to continuous seagrass landscapes. Nested within the fragmentation categories were high and low levels of seagrass cover. Hierarchical analysis of variance techniques were used to differentiate between the different fragmentation categories and levels of seagrass cover within the fragmentation categories. Principal component analysis was also employed to determine strong correlations between the indices. The results suggest that (1) landscape ision and (2) area-weighted mean perimeter to area ratio were the most appropriate indices for differentiating between independent levels of seagrass fragmentation. The splitting index may also be useful when the detection of small differences in cover is important.
Seed dormancy and germination of Halophila ovalis mediated by simulated seasonal temperature changes
Publisher: Elsevier BV
Date: 11-2017
High rates of herbivory in remote northwest Australian seagrass meadows by rabbitfish and green turtles
Publisher: Inter-Research Science Center
Date: 29-04-2021
DOI: 10.3354/MEPS13657
Abstract: Herbivory is a key ecological process that often determines the composition and abundance of plants. Estimates of herbivory in seagrass meadows are typically lower than those in other vegetated coastal ecosystems, but herbivory can be intense when large herbivorous vertebrates are abundant. We surveyed rates of herbivory on 2 species of tropical seagrasses ( Thalassia hemprichii and Enhalus acoroides ), the abundance of herbivorous vertebrates, and the diet of 2 abundant herbivorous vertebrates (the green turtle Chelonia mydas and the rabbitfish Siganus lineatus ) in lagoons adjacent to remote islands off northwestern Australia. Rates of herbivory in some deployments of tethered seagrass were more than 1000 times higher than rates of production and were among the highest recorded. Consumption exceeded production in half the deployments (9 of 18). Remote underwater video revealed that S. lineatus was the most abundant herbivore. Stomachs of S. lineatus contained mostly seagrass, and models based on stable isotopes indicated that seagrass was the primary source of nutrition. Stomach contents of C. mydas were more variable, containing seagrass and macroalgae (although the s le size was low), but models based on stable isotopes indicated that seagrass was likely the primary source of nutrition. Multiple lines of evidence suggest that the high rates of herbivory on the seagrasses T. hemprichii and E. acoroides are mainly due to direct consumption by the abundant S. lineatus , and perhaps also C. mydas . Seagrass is the primary contributor to the nutrition of both species.
Unravelling complexity in seagrass systems for management: Australia as a microcosm
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.SCITOTENV.2015.04.061
Abstract: Environmental decision-making applies transdisciplinary knowledge to deliver optimal outcomes. Here we synthesise various aspects of seagrass ecology to aid environmental decision-making, management and policy. Managers often mediate conflicting values and opinions held by different stakeholders. Critical to this role is understanding the drivers for change, effects of management actions and societal benefits. We use the ersity of seagrass habitats in Australia to demonstrate that knowledge from numerous fields is required to understand seagrass condition and resilience. Managers are often time poor and need access to synthesised assessments, commonly referred to as narratives. However, there is no single narrative for management of seagrass habitats in Australia, due to the ersity of seagrass meadows and dominant pressures. To assist the manager, we developed a classification structure based on attributes of seagrass life history, habitat and meadow form. Seagrass communities are formed from species whose life history strategies can be described as colonising, opportunistic or persistent. They occupy habitats defined by the range and variability of their abiotic environment. This results in seagrass meadows that are either transitory or enduring. Transitory meadows may come and go and able to re-establish from complete loss through sexual reproduction. Enduring meadows may fluctuate in biomass but maintain a presence by resisting pressures across multiple scales. This contrast reflects the interaction between the spatial and temporal aspects of species life history and habitat variability. Most management and monitoring strategies in place today favour enduring seagrasses. We adopt a functional classification of seagrass habitats based on modes of resilience to inform management for all seagrass communities. These concepts have world-wide relevance as the Australian case-studies have many analogues throughout the world. Additionally, the approach used to classify primary scientific knowledge into synthesised categories to aid management has value for many other disciplines interfacing with environmental decision-making.
Seagrasses of south-west Australia: A conceptual synthesis of the world's most diverse and extensive seagrass meadows
Publisher: Elsevier BV
Date: 11-2007
Sulfide intrusion in a habitat forming seagrass can be predicted from relative abundance of sulfur cycling genes in sediments
Publisher: Elsevier BV
Date: 03-2023
Deep Image Representations for Coral Image Classification
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2019
Abundance of Ruppia megacarpa Mason in a Seasonally Variable Estuary
Publisher: Elsevier BV
Date: 04-1999
Contrasting responses of seagrass transplants (Posidonia australis) to nitrogen, phosphorus and iron addition in an estuary and a coastal embayment
Publisher: Elsevier BV
Date: 03-2009
Challenges for Restoration of Coastal Marine Ecosystems in the Anthropocene
Publisher: Frontiers Media SA
Date: 04-11-2020
Variation in reproductive effort, genetic diversity and mating systems across Posidonia australis seagrass meadows in Western Australia
Publisher: Oxford University Press (OUP)
Date: 08-2020
Abstract: Populations at the edges of their geographical range tend to have lower genetic ersity, smaller effective population sizes and limited connectivity relative to centre of range populations. Range edge populations are also likely to be better adapted to more extreme conditions for future survival and resilience in warming environments. However, they may also be most at risk of extinction from changing climate. We compare reproductive and genetic data of the temperate seagrass, Posidonia australis on the west coast of Australia. Measures of reproductive effort (flowering and fruit production and seed to ovule ratios) and estimates of genetic ersity and mating patterns (nuclear microsatellite DNA loci) were used to assess sexual reproduction in northern range edge (low latitude, elevated salinities, Shark Bay World Heritage Site) and centre of range (mid-latitude, oceanic salinity, Perth metropolitan waters) meadows in Western Australia. Flower and fruit production were highly variable among meadows and there was no significant relationship between seed to ovule ratio and clonal ersity. However, Shark Bay meadows were two orders of magnitude less fecund than those in Perth metropolitan waters. Shark Bay meadows were characterized by significantly lower levels of genetic ersity and a mixed mating system relative to meadows in Perth metropolitan waters, which had high genetic ersity and a completely outcrossed mating system. The combination of reproductive and genetic data showed overall lower sexual productivity in Shark Bay meadows relative to Perth metropolitan waters. The mixed mating system is likely driven by a combination of local environmental conditions and pollen limitation. These results indicate that seagrass restoration in Shark Bay may benefit from sourcing plant material from multiple reproductive meadows to increase outcrossed pollen availability and seed production for natural recruitment.
A Systematic Review of How Multiple Stressors From an Extreme Event Drove Ecosystem-Wide Loss of Resilience in an Iconic Seagrass Community
Publisher: Frontiers Media SA
Date: 29-07-2019
Comment on ‘Seagrass Viviparous Propagules as a Potential Long-Distance Dispersal Mechanism’ by A. C. G. Thomson et al.
Publisher: Springer Science and Business Media LLC
Date: 27-01-2016
Severe loss of anemones and anemonefishes from a premier tourist attraction at the Houtman Abrolhos Islands, Western Australia
Publisher: Springer Science and Business Media LLC
Date: 21-05-2014
Reproduction at the extremes: pseudovivipary, hybridization and genetic mosaicism inPosidonia australis(Posidoniaceae)
Publisher: Oxford University Press (OUP)
Date: 17-11-2015
DOI: 10.1093/AOB/MCV162
Science behind management of Shark Bay and Florida Bay, two P-limited subtropical systems with different climatology and human pressures
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/MF12280
Abstract: This special issue on ‘Science for the management of subtropical embayments: ex les from Shark Bay and Florida Bay’ is a valuable compilation of in idual research outcomes from Florida Bay and Shark Bay from the past decade and addresses gaps in our scientific knowledge base in Shark Bay especially. Yet the compilation also demonstrates excellent research that is poorly integrated, and driven by interests and issues that do not necessarily lead to a more integrated stewardship of the marine natural values of either Shark Bay or Florida Bay. Here we describe the status of our current knowledge, introduce the valuable extension of the current knowledge through the papers in this issue and then suggest some future directions. For management, there is a need for a multidisciplinary international science program that focusses research on the ecological resilience of Shark Bay and Florida Bay, the effect of interactions between physical environmental drivers and biological control through behavioural and trophic interactions, and all under increased anthropogenic stressors. Shark Bay offers a ‘pristine template’ for this scale of study.
Photosynthetic response to globally increasing CO2 of co‐occurring temperate seagrass species
Publisher: Wiley
Date: 22-03-2016
DOI: 10.1111/PCE.12658
Abstract: Photosynthesis of most seagrass species seems to be limited by present concentrations of dissolved inorganic carbon (DIC). Therefore, the ongoing increase in atmospheric CO2 could enhance seagrass photosynthesis and internal O2 supply, and potentially change species competition through differential responses to increasing CO2 availability among species. We used short-term photosynthetic responses of nine seagrass species from the south-west of Australia to test species-specific responses to enhanced CO2 and changes in HCO3 (-) . Net photosynthesis of all species except Zostera polychlamys were limited at pre-industrial compared to saturating CO2 levels at light saturation, suggesting that enhanced CO2 availability will enhance seagrass performance. Seven out of the nine species were efficient HCO3 (-) users through acidification of diffusive boundary layers, production of extracellular carbonic anhydrase, or uptake and internal conversion of HCO3 (-) . Species responded differently to near saturating CO2 implying that increasing atmospheric CO2 may change competition among seagrass species if co-occurring in mixed beds. Increasing CO2 availability also enhanced internal aeration in the one species assessed. We expect that future increases in atmospheric CO2 will have the strongest impact on seagrass recruits and sparsely vegetated beds, because densely vegetated seagrass beds are most often limited by light and not by inorganic carbon.
Coastal fish assemblages reflect geological and oceanographic gradients within an Australian zootone
Publisher: Public Library of Science (PLoS)
Date: 22-11-2013
A sediment bioturbator bottleneck to seedling recruitment for the seagrass Posidonia australis
Publisher: Inter-Research Science Center
Date: 14-05-2018
DOI: 10.3354/MEPS12550
Ecological significance of seagrasses: Assessment for management of environmental impact in Western Australia
Publisher: Elsevier BV
Date: 2001
Extensive polyploid clonality was a successful strategy for seagrass to expand into a newly submerged environment
Publisher: The Royal Society
Date: 06-2022
Abstract: Polyploidy has the potential to allow organisms to outcompete their diploid progenitor(s) and occupy new environments. Shark Bay, Western Australia, is a World Heritage Area dominated by temperate seagrass meadows including Poseidon's ribbon weed, Posidonia australis . This seagrass is at the northern extent of its natural geographic range and experiences extremes in temperature and salinity. Our genomic and cytogenetic assessments of 10 meadows identified geographically restricted, diploid clones (2 n = 20) in a single location, and a single widespread, high-heterozygosity, polyploid clone (2 n = 40) in all other locations. The polyploid clone spanned at least 180 km, making it the largest known ex le of a clone in any environment on earth. Whole-genome duplication through polyploidy, combined with clonality, may have provided the mechanism for P. australis to expand into new habitats and adapt to new environments that became increasingly stressful for its diploid progenitor(s). The new polyploid clone probably formed in shallow waters after the inundation of Shark Bay less than 8500 years ago and subsequently expanded via vegetative growth into newly submerged habitats.
Production and accumulation of reef framework by calcifying corals and macroalgae on a remote Indian Ocean cay
Publisher: Copernicus GmbH
Date: 15-03-2023
Abstract: Abstract. Coral reefs face increasing pressures in response to unprecedented rates of environmental change at present. The coral reef physical framework is formed through the production of calcium carbonate (CaCO3) and maintained by marine organisms, primarily hermatypic corals, and calcifying algae. The northern part of Western Australia, known as the Kimberley, has largely escaped land-based anthropogenic impacts and this study provides important metabolic data on reef-building organisms from an undisturbed set of marine habitats. From the reef platform of Browse Island, located on the mid-shelf just inside the 200 m isobath off the Kimberley coast, specimens of the dominant coral (six species) and algal (five species) taxa were collected and incubated ex situ in light and dark shipboard experimental mesocosms for 4 h to measure rates of calcification and production patterns of oxygen. During experimental light and dark incubations, all algae were net autotrophic producing 6 to 111 mmolO2m-2d-1. In contrast, most corals were net consumers of O2 with average net fluxes ranging from −42 to 47 mmolO2m-2d-1. The net change in pH was generally negative for corals and calcifying algae (−0.01 to −0.08 h−1). Resulting net calcification rates (1.9 to 9.9 gCaCO3m-2d-1) for corals and calcifying algae (Halimeda and Galaxura) were all positive and were strongly correlated with net O2 production. In intertidal habitats around Browse Island, estimated relative contributions of coral and Halimeda to the reef production of CaCO3 were similar at around 600 to 840 gm-2yr-1. The low reef platform had very low coral cover of 3 % which made a smaller contribution to calcification of ∼ 240 gCaCO3m-2yr-1. Calcification on the subtidal reef slope was predominantly from corals, producing ∼ 1540 gCaCO3m-2yr-1, twice that of Halimeda. These data provide the first measures of community metabolism from the offshore reef systems of the Kimberley. The relative contributions of the main reef builders, in these undisturbed areas, to net community metabolism and CaCO3 production is important to understand exclusively climate-driven negative effects on tropical reefs.
Seagrass loss associated with boat moorings at Rottnest Island, Western Australia
Publisher: Elsevier BV
Date: 1995
Benthic microalgae and nutrient dynamics in wave-disturbed environments in Marmion Lagoon, Western Australia, compared with less disturbed mesocosms
Publisher: Elsevier BV
Date: 10-1998
Probabilistic large-area mapping of seagrass species distributions
Publisher: Wiley
Date: 2007
DOI: 10.1002/AQC.772
Survival of juvenile Ecklonia radiata sporophytes after canopy loss
Publisher: Elsevier BV
Date: 09-2007
Contemporary connectivity is sustained by windand current-driven seed dispersal among seagrass meadows
Publisher: Springer Science and Business Media LLC
Date: 02-04-2015
Analysing the dynamics and relative influence of variables affecting ecosystem responses using functional PCA and boosted regression trees: A seagrass case study
Publisher: Wiley
Date: 12-08-2019
The effect of kelp bed disturbance on the abundance and feeding behaviour of fishes on high-relief reefs
Publisher: Informa UK Limited
Date: 03-2010
Contrasting influence of sea urchins on attached and drift macroalgae
Publisher: Inter-Research Science Center
Date: 2005
DOI: 10.3354/MEPS299101
The interaction of environment and genetic diversity within meadows of the seagrass Posidonia australis (Posidoniaceae)
Publisher: Inter-Research Science Center
Date: 23-06-2014
DOI: 10.3354/MEPS10812
Benthic assemblage composition on subtidal reefs along a latitudinal gradient in Western Australia
Publisher: Elsevier BV
Date: 2010
Salinity stress drives herbivory rates and selective grazing in subtidal seagrass communities
Publisher: Public Library of Science (PLoS)
Date: 21-03-2019
Operationalizing marketable blue carbon
Publisher: Elsevier BV
Date: 05-2022
Heat stress of two tropical seagrass species during low tides - impact on underwater net photosynthesis, dark respiration and diel in situ internal aeration
Publisher: Wiley
Date: 23-02-2016
DOI: 10.1111/NPH.13900
Abstract: Seagrasses grow submerged in aerated seawater but often in low O 2 sediments. Elevated temperatures and low O 2 are stress factors. Internal aeration was measured in two tropical seagrasses, Thalassia hemprichii and Enhalus acoroides , growing with extreme tides and diel temperature litudes. Temperature effects on net photosynthesis ( P N ) and dark respiration ( R D ) of leaves were evaluated. Daytime low tide was characterized by high p O 2 (54 kP a), pH (8.8) and temperature (38°C) in shallow pools. As P N was maximum at 33°C (9.1 and 7.2 μmol O 2 m −2 s −1 in T. hemprichii and E. acoroides , respectively), the high temperatures and reduced CO 2 would have diminished P N , whereas R D increased (Q 10 of 2.0–2.7) above that at 33°C (0.45 and 0.33 μmol O 2 m −2 s −1 , respectively). During night‐time low tides, O 2 declined resulting in shoot base anoxia in both species, but incoming water containing c . 20 kP a O 2 relieved the anoxia. Shoots exposed to 40°C for 4 h showed recovery of P N and R D , whereas 45°C resulted in leaf damage. These seagrasses are ‘living near the edge’, tolerant of current diel O 2 and temperature extremes, but if temperatures rise both species may be threatened in this habitat.
A genetic assessment of a successful seagrass meadow (Posidonia australis) restoration trial
Publisher: Wiley
Date: 2013
DOI: 10.1111/EMR.12028
From fronds to fish: the use of indicators for ecological monitoring in marine benthic ecosystems, with case studies from temperate Western Australia
Publisher: Springer Science and Business Media LLC
Date: 15-09-2011
Regional-scale benthic monitoring for Ecosystem-Based Fisheries Management (EBFM) using an Autonomous Underwater Vehicle (AUV)
Publisher: Oxford University Press (OUP)
Date: 18-05-2012
Abstract: Smale, D. A., Kendrick, G. A., Harvey, E. S., Langlois, T. J., Hovey, R. K., Van Niel, K. P., Waddington, K. I., Bellchambers, L. M., Pember, M. B., Babcock, R. C., Vanderklift, M. A., Thomson, D. P., Jakuba, M. V., Pizarro, O., and Williams, S. B. 2012. Regional-scale benthic monitoring for ecosystem-based fisheries management (EBFM) using an autonomous underwater vehicle (AUV). – ICES Journal of Marine Science, 69: 1108–1118. Monitoring marine habitats and bio ersity is critical for understanding ecological processes, conserving natural resources, and achieving ecosystem-based fisheries management (EBFM). Here, we describe the application of autonomous underwater vehicle (AUV) technology to conduct ongoing monitoring of benthic habitats at two key locations in Western Australia. Benthic assemblages on rocky reefs were s led with an AUV, which captured 000 geo-referenced images. Surveys were designed to obtain 100% coverage of 25 × 25 m patches of benthic habitat. In 2010, multiple patches were surveyed at 15–40-m depths at three reference sites at the Houtman Abrolhos Islands and at six reference sites at Rottnest Island. The following year, repeat surveys of the same geo-referenced patches were conducted. Benthic assemblages at the Houtman Abrolhos Islands were varied in that one reference site was dominated by hard corals, whereas the other two were macroalgae dominated. Conversely, assemblages at Rottnest Island were dominated by the kelp Ecklonia radiata. The AUV resurveyed each patch with high precision and demonstrated adequate power to detect change. Repeated observations at the reference sites will track natural variability in benthic habitat structure, which in turn will facilitate the detection of ecological change and ultimately feed back into EBFM processes.
Extinction risk assessment of the world’s seagrass species
Publisher: Elsevier BV
Date: 07-2011
Combining environmental gradients to explain and predict the structure of demersal fish distributions
Publisher: Wiley
Date: 04-2010
Threats to Macroalgal Diversity: Marine Habitat Destruction and Fragmentation, Pollution and Introduced Species
Publisher: Walter de Gruyter GmbH
Date: 1998
Seagrass ecosystems as a globally significant carbon stock
Publisher: Springer Science and Business Media LLC
Date: 20-05-2012
DOI: 10.1038/NGEO1477
The effects of light and thallus scour from Ecklonia radiata canopy on an associated foliose algal assemblage: the importance of photoacclimation
Publisher: Springer Science and Business Media LLC
Date: 05-2004
Seasonal changes in Epiphytic Macro-Algae Assemblages between Offshore Exposed and Inshore Protected Posidonia sinuosa Cambridge et Kuo Seagrass Meadows, Western Australia
Publisher: Walter de Gruyter GmbH
Date: 1997
Effects of high salinity from desalination brine on growth, photosynthesis, water relations and osmolyte concentrations of seagrass Posidonia australis
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.MARPOLBUL.2016.11.066
Abstract: Highly saline brines from desalination plants expose seagrass communities to salt stress. We examined effects of raised salinity (46 and 54psu) compared with seawater controls (37psu) over 6weeks on the seagrass, Posidonia australis, growing in tanks with the aim of separating effects of salinity from other potentially deleterious components of brine and determining appropriate bioindicators. Plants survived exposures of 2-4weeks at 54psu, the maximum salinity of brine released from a nearby desalination plant. Salinity significantly reduced maximum quantum yield of PSII (chlorophyll a fluorescence emissions). Leaf water potential (Ψ
Erratum: A comparison of temperate reef fish assemblages recorded by three underwater stereo-video techniques (Marine Biology (2005) 148 (415-425) DOI: doi.org/10.1007/s00227-005-0090-6)
Publisher: Springer Science and Business Media LLC
Date: 09-02-2006
Global analysis of seagrass restoration: the importance of large‐scale planting
Publisher: Wiley
Date: 25-11-2015
Regional Differences in kelp-associated algal assemblages on temperate limestone reefs in south-western Australia
Publisher: Wiley
Date: 24-10-2003
Influence of Sargassum spp. Attached to Rhodoliths on Sampling Effort and Demographic Analyses of Sargassum spp. (Sargassaceae, Phaeophyta) Attached to a Reef
Publisher: Walter de Gruyter GmbH
Date: 1997
The cycle of seagrass life: From flowers to new meadows
Publisher: Wiley
Date: 31-08-2023
DOI: 10.1002/ECE3.10456
Abstract: Understanding sexual reproduction and recruitment in seagrasses is crucial to their conservation and restoration. Flowering, seed production, seed recruitment, and seedling establishment data for the seagrass Posidonia australis was collected annually between 2013 and 2018 in meadows at six locations around Rottnest Island, Western Australia. Variable annual rates of flowering and seed production were observed among meadows between northern and southern sides of the island and among years. Meadows on the northern shore consistently flowered more intensely and produced more seeds across the years of the survey. Inter‐site variation in clonal ersity and size of clones, seed production, wind and surface currents during pollen and seed release, and the large, but variable, impact of seed predation are likely the principal drivers of successful recruitment into established meadows and in colonizing unvegetated sands. The prolific but variable annual reproductive investment increases the probability of low levels of continuous recruitment from seed in this seagrass, despite high rates of abiotic and biotic disturbance at seedling, shoot, and patch scales. This strategy also imparts a level of ecological resilience to this long‐lived and persistent species.
The genome of a southern hemisphere seagrass species (Zostera muelleri)
Publisher: Oxford University Press (OUP)
Date: 03-07-2016
DOI: 10.1104/PP.16.00868
Not all pathways are the same – unique adaptations to submerged environments emerge from comparative seagrass genomics
Publisher: Cold Spring Harbor Laboratory
Date: 24-11-2022
DOI: 10.1101/2022.11.22.517588
Abstract: Seagrasses are an ecologically important group of plants that have returned to the sea from terrestrial ancestors on at least three occasions (Cymodoceaceae, Posidoniaceae, Zosteraceae). Seagrass-specific genomic adaptations to marine life are known from the Zosteraceae. However, independent lineages may have devised different solutions to life underwater. Here, we present two new genome assemblies from endemic Australian seagrasses, Amphibolis antarctica (Cymodoceaceae) and Posidonia australis (Posidoniaceae). We found large differences in genome size between Amphibolis and Posidonia driven by repeat expansion in Posidonia . We show that parts of ethylene pathways known to be lost in Zosteraceae are partially retained in older seagrass lineages (Cymodoceaeceae and Posidoniaceae). We describe adaptations within salinity, disease resistance, cell wall, and photosynthesis-related pathways not shared with other seagrasses. These findings provide insight into the impact of recolonising marine environments on formerly terrestrial plant genomes, with some adaptations previously thought to be universal to marine living not having occurred in A. antarctica and P. australis .
Cross-depth connectivity shows that deep kelps may act as refugia by reseeding climate-vulnerable shallow beds
Publisher: Wiley
Date: 03-2023
DOI: 10.1002/ECS2.4471
Abstract: Refugia are habitats where species can survive or retreat to during environmental disturbances. One key assumption of habitats that constitute refugia is that they may assist in the persistence of impacted populations through the provision of reproductive propagules. This “reseeding” hypothesis assumes that demographic connectivity exists between refugia and impacted habitats. We tested this hypothesis for the kelp Ecklonia radiata , a temperate marine foundation species dominant in the temperate coast of Australia. Our study site was the coast of Western Australia, a system where deep habitats are considered to act as refugia for their shallow counterparts, yet, for which estimations of population connectivity have overlooked propagule dispersal across depth. Here, we simulated the dominant ocean circulation conditions in a three‐dimensional oceanographic model and the dispersal of kelp propagules by incorporating physical properties of zoospores within the model. The trajectories of kelp propagules were tracked and analyzed to identify their probability of settlement within the domain of the study. Measurements of kelp fecundity across depth were obtained within the study region, and used to estimate zoospore settlement densities. Here, we show that deep populations of E. radiata have the capacity to supply zoospores to shallow reefs. Our results show that zoospores released at deeper beds (40 m of depth) are transported to shallow reefs ( m of depth) and that settlement densities are sufficient to drive kelp fertilization. Analysis of particle exchange among depths also indicates that mid‐depth reefs (~25 m of depth) act as important “stepping stones” for cross‐depth connectivity, enhancing dispersal between the shallowest and deepest locations, which is especially important when reefs of different depths are separated by tens of kilometers. We show that after an environmental disturbance, persistent deep kelps may act as refugia by sourcing propagules and reseeding impacted shallow reefs, provided that environmental conditions are adequate for kelp recruitment and growth. This study demonstrates that through propagule exchange, populations of habitat‐building species living in areas undamaged by biophysical disturbances may reseed their impacted counterparts, aid their recovery if conditions are adequate for regrowth, and ensure their persistence.
Modelling distribution of marine benthos from hydroacoustics and underwater video
Publisher: Elsevier BV
Date: 08-2008
A marine heatwave drives massive losses from the world’s largest seagrass carbon stocks
Publisher: Springer Science and Business Media LLC
Date: 19-03-2018
Belowground stressors and long-term seagrass declines in a historically degraded seagrass ecosystem after improved water quality
Publisher: Springer Science and Business Media LLC
Date: 31-10-2017
DOI: 10.1038/S41598-017-14044-1
Abstract: Continued seagrass declines in ecosystems with improved water quality may be driven by sediment stressors. One of the most cited ex les of a seagrass ecosystem with declines is Cockburn Sound, Western Australia, where 75% of seagrasses (2169 ha) were lost in the 1960s–1980s due to poor water quality. Water quality has subsequently improved in Cockburn Sound, yet shoot density declines continue in some areas. Here, we investigated if sediment stressors (sulfide intrusion and heavy metals) contributed to declining Posidonia sinuosa shoot densities in Cockburn Sound. Seagrass δ 34 S were depleted at sites with a history of seagrass declines, indicating seagrasses at these sites were under sulfide stress. Heavy metals (Fe, Zn, Mn, Cr, Cu and Cd) in sediments and seagrasses did not show clear patterns with shoot density or biomass, and largely decreased from similar measurements in the late 1970s. However, seagrass cadmium concentrations were negatively correlated to seagrass biomass and shoot density. High cadmium concentrations interfere with sulfur metabolism in terrestrial plants, but impacts on seagrasses remain to be explored. Given that sulfide intrusion can prevent recolonization and drive seagrass declines, management plans in degraded seagrass ecosystems should include management of sediment stressors and water quality to provide comprehensive management.
Consistent abundance distributions of marine fishes in an old, climatically buffered, infertile seascape
Publisher: Wiley
Date: 15-12-2012
Historic and contemporary biogeographic perspectives on range-wide spatial genetic structure in a widespread seagrass
Publisher: Wiley
Date: 03-2023
DOI: 10.1002/ECE3.9900
Abstract: Historical and contemporary processes drive spatial patterns of genetic ersity. These include climate‐driven range shifts and gene flow mediated by biogeographical influences on dispersal. Assessments that integrate these drivers are uncommon, but critical for testing biogeographic hypotheses. Here, we characterize intraspecific genetic ersity and spatial structure across the entire distribution of a temperate seagrass to test marine biogeographic concepts for southern Australia. Predictive modeling was used to contrast the current Posidonia australis distribution to its historical distribution during the Last Glacial Maximum (LGM). Spatial genetic structure was estimated for 44 s led meadows from across the geographical range of the species using nine microsatellite loci. Historical and contemporary distributions were similar, with the exception of the Bass Strait. Genetic clustering was consistent with the three currently recognized biogeographic provinces and largely consistent with the finer‐scale IMCRA bioregions. Discrepancies were found within the Flindersian province and southwest IMCRA bioregion, while two regions of admixture coincided with transitional IMCRA bioregions. Clonal ersity was highly variable but positively associated with latitude. Genetic differentiation among meadows was significantly associated with oceanographic distance. Our approach suggests how shared seascape drivers have influenced the capacity of P. australis to effectively track sea level changes associated with natural climate cycles over millennia, and in particular, the recolonization of meadows across the Continental Shelf following the LGM. Genetic structure associated with IMCRA bioregions reflects the presence of stable biogeographic barriers, such as oceanic upwellings. This study highlights the importance of biogeography to infer the role of historical drivers in shaping extant ersity and structure.
Ecological significance and commercial harvesting of drifting and beach-cast macro-algae and seagrasses in Australia: a review
Publisher: Springer Science and Business Media LLC
Date: 1997
A novel adaptation facilitates seed establishment under marine turbulent flows
Publisher: Springer Science and Business Media LLC
Date: 23-12-2019
DOI: 10.1038/S41598-019-56202-7
Abstract: Seeds of Australian species of the seagrass genus Posidonia are covered by a membranous wing that we hypothesize plays a fundamental role in seed establishment in sandy, wave swept marine environments. Dimensions of the seed and membrane were quantified under electron microscopy and micro-CT scans, and used to model rotational, drag and lift forces. Seeds maintain contact with the seabed in the presence of strong turbulence: the larger the wing, the more stable the seed. Wing surface area increases from P. sinuosa P. australis P.coriacea correlating with their ability to establish in increasingly energetic environments. This unique seed trait in a marine angiosperm corresponds to adaptive pressures imposed on seagrass species along 7,500 km of Australia’s coastline, from open, high energy coasts to calmer environments in bays and estuaries.
Patch dynamics driven by wave exposure in subtidal temperate seaweeds are exacerbated by warming oceans
Publisher: Inter-Research Science Center
Date: 10-03-2022
DOI: 10.3354/MEPS13989
Abstract: Over the past decades, ocean temperatures have been steadily increasing and are projected to continue to do so, stressing many temperate marine organisms. Changing temperatures do not affect ecosystems in isolation, but interact with many other factors in shaping ecological communities. We investigated the changes over 2 decades in subtidal temperate seaweed communities over a wave exposure gradient in Western Australia, a global warming hotspot. We found higher ersity in the seaweed community and a higher proportion of biomass of species with a warm affinity (expressed as the tropicalization index: TI) over time. There was no decline in biomass of the dominant habitat-forming kelp Ecklonia radiata on low wave exposure reefs, while it was patchier and comprised a lower proportion of the total seaweed biomass on the medium and high wave exposure reefs. Furthermore, the presence of E. radiata was disproportionally associated with low abundances of seaweeds with warm affinity. The increasing patchiness of E. radiata likely provided a competitive release for other seaweeds, and the increase in abundance of Scytothalia dorycarpa likely provided a compensatory effect which resulted in a lower than expected TI. We found no indication of an ameliorating effect by wave exposure, and conclude that the patch dynamics driven by wave exposure are more likely exacerbated by increasing ocean temperatures on subtidal temperate reefs. If this continues, the reduction in E. radiata and increase in warm affiliated seaweeds will result in a more erse seaweed community, but one with a lower standing biomass.
Season and sediment nutrient additions affect root architecture in the temperate seagrasses Posidonia australis and P. sinuosa
Publisher: Inter-Research Science Center
Date: 02-02-2012
DOI: 10.3354/MEPS09483
Canopy interactions and physical stress gradients in subtidal communities
Publisher: Wiley
Date: 14-05-2015
DOI: 10.1111/ELE.12446
Abstract: Species interactions are integral drivers of community structure and can change from competitive to facilitative with increasing environmental stress. In subtidal marine ecosystems, however, interactions along physical stress gradients have seldom been tested. We observed seaweed canopy interactions across depth and latitudinal gradients to test whether light and temperature stress structured interaction patterns. We also quantified interspecific and intraspecific interactions among nine subtidal canopy seaweed species across three continents to examine the general nature of interactions in subtidal systems under low consumer pressure. We reveal that positive and neutral interactions are widespread throughout global seaweed communities and the nature of interactions can change from competitive to facilitative with increasing light stress in shallow marine systems. These findings provide support for the stress gradient hypothesis within subtidal seaweed communities and highlight the importance of canopy interactions for the maintenance of subtidal marine habitats experiencing environmental stress.
Predictors of marine genetic structure in the Indo-Australian Archipelago
Publisher: Elsevier BV
Date: 09-2021
Turf algal epiphytes metabolically induce local pH increase, with implications for underlying coralline algae under ocean acidification
Publisher: Elsevier BV
Date: 10-2015
Biogenic habitat structure of seaweeds change along a latitudinal gradient in ocean temperature
Publisher: Elsevier BV
Date: 04-2011
Cable bacteria at oxygen‐releasing roots of aquatic plants: a widespread and diverse plant–microbe association
Publisher: Wiley
Date: 21-05-2021
DOI: 10.1111/NPH.17415
Abstract: Cable bacteria are sulfide‐oxidising, filamentous bacteria that reduce toxic sulfide levels, suppress methane emissions and drive nutrient and carbon cycling in sediments. Recently, cable bacteria have been found associated with roots of aquatic plants and rice ( Oryza sativa ). However, the extent to which cable bacteria are associated with aquatic plants in nature remains unexplored. Using newly generated and public 16S rRNA gene sequence datasets combined with fluorescence in situ hybridisation, we investigated the distribution of cable bacteria around the roots of aquatic plants, encompassing seagrass (including seagrass seedlings), rice, freshwater and saltmarsh plants. Diverse cable bacteria were found associated with roots of 16 out of 28 plant species and at 36 out of 55 investigated sites, across four continents. Plant‐associated cable bacteria were confirmed across a variety of ecosystems, including marine coastal environments, estuaries, freshwater streams, isolated pristine lakes and intensive agricultural systems. This pattern indicates that this plant–microbe relationship is globally widespread and neither obligate nor species specific. The occurrence of cable bacteria in plant rhizospheres may be of general importance to vegetation vitality, primary productivity, coastal restoration practices and greenhouse gas balance of rice fields and wetlands.
Extreme climate events lower resilience of foundation seagrass at edge of biogeographical range
Publisher: Wiley
Date: 06-08-2014
Impacts of climate change in a global hotspot for temperate marine biodiversity and ocean warming
Publisher: Elsevier BV
Date: 04-2011
Depth moderates loss of marine foundation species after an extreme marine heatwave
Publisher: The Royal Society
Date: 10-06-2020
Abstract: Marine heatwaves (MHWs) have been documented around the world, causing widespread mortality of numerous benthic species on shallow reefs (less than 15 m depth). Deeper habitats are hypothesized to be a potential refuge from environmental extremes, though we have little understanding of the response of deeper benthic communities to MHWs. Here, we show how increasing depth moderates the response of seaweed- and coral-dominated benthic communities to an extreme MHW across a subtropical–temperate biogeographical transition zone. Benthic community composition and key habitat-building species were characterized across three depths (15, 25 and 40 m) before and several times after the 2011 Western Australian MHW to assess resistance during and recovery after the heatwave. We found high natural variability in benthic community composition along the biogeographic transition zone and across depths with a clear shift in the composition after the MHW in shallow (15 m) sites but a lot less in deeper communities (40 m). Most importantly, key habitat-building seaweeds such as Ecklonia radiata and Syctothalia dorycarpa which had catastrophic losses on shallow reefs, remained and were less affected in deeper communities. Evidently, deep reefs have the potential to act as a refuge during MHWs for the foundation species of shallow reefs in this region.
Benthic microalgae: comparisons of chlorophyll a in mesocosms and field sites
Publisher: Springer Netherlands
Date: 1996
Edge Effects along a Seagrass Margin Result in an Increased Grazing Risk on Posidonia australis Transplants
Publisher: Public Library of Science (PLoS)
Date: 14-10-2015
Subtidal macroalgal richness, diversity and turnover, at multiple spatial scales, along the southwestern Australian coastline
Publisher: Elsevier BV
Date: 2011
Automatic annotation of coral reefs using deep learning
Publisher: IEEE
Date: 09-2016
Genetic diversity in threatened Posidonia australis seagrass meadows
Publisher: Springer Science and Business Media LLC
Date: 28-01-2014
Efficiently measuring complex sessile epibenthic organisms using a novel photogrammetric technique
Publisher: Elsevier BV
Date: 11-2006
Do surrogates describe patterns in marine macroalgal diversity in the Recherche Archipelago, temperate Australia?
Publisher: Wiley
Date: 2006
DOI: 10.1002/AQC.729
How does spatial resolution affect model performance? A case for ensemble approaches for marine benthic mesophotic communities
Publisher: Wiley
Date: 02-05-2019
DOI: 10.1111/JBI.13581
Inorganic Nutrient Supplements Constrain Restoration Potential of Seedlings of the Seagrass, Posidonia australis
Publisher: Wiley
Date: 18-12-2013
DOI: 10.1111/REC.12072
A comparative assessment of approaches and outcomes for seagrass revegetation in Shark Bay and Florida Bay
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/MF12032
Abstract: Here, we review the literature to evaluate seagrass revegetation projects focussed on Posidonia australis and Amphibolis antarctica, the main affected species in Shark Bay in the World Heritage Area in Western Australia, together with projects from Florida Bay, an analogous system with a long history of seagrass revegetation. We assessed the effectiveness of anchoring planting units, plant-unit density and size on planting-unit survival. We found no positive trends in our assessment, suggesting that there is no discrete technique, approach or technology that could be used with confidence to deliver cost-effective, scalable revegetation. Of concern was that revegetation success was evaluated over comparatively short time frames (1–3 years), driven by the strict time frames or deadlines of governing grant funding and commercial activities, leading to concerns that long-term revegetation outcomes may be difficult to assess with confidence. Several factors influenced revegetation outcomes which were grouped into three ‘filter’ categories abiotic, biotic and socioeconomic. We recommend that future revegetation programs involving seagrass have greater emphasis on understanding how these filters act independently or collectively to drive successful revegetation as well as developing cost-effective, proven and scalable technology supported by longer-term monitoring to ensure revegetation programs do achieve the desired ecological outcomes.
Colonizing tropical seagrasses increase root exudation under fluctuating and continuous low light
Publisher: Wiley
Date: 16-11-2018
DOI: 10.1002/LNO.10746
The distribution of seagrass species in shark bay, Western Australia, with notes on their ecology
Publisher: Elsevier BV
Date: 05-1988
Genetic signatures of Bassian glacial refugia and contemporary connectivity in a marine foundation species
Publisher: Wiley
Date: 04-08-2016
DOI: 10.1111/JBI.12822
Nutrient status of seagrasses cannot be inferred from system-scale distribution of phosphorus in Shark Bay, Western Australia
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/MF12026
Abstract: Differences in phosphorus (P) availability can influence the ecology and physiology of seagrass communities and are usually inferred from changes in the relative P content in seagrass leaves. Shark Bay is a subtropical marine embayment, with decreasing P concentrations in the water column and sediments from north to south across the entire embayment. We examined the P and nitrogen (N) content of seagrass leaves and P content of sediments across the Faure Sill and Wooramel delta region of Shark Bay, to determine whether the leaf content of seagrasses in Shark Bay also decreased from north to south over smaller spatial scales. Nutrient content of Amphibolis antarctica and Halodule uninervis were highly variable and were not strongly correlated with sediment P concentrations. Mean N : P ratios of seagrasses ( .5) were not indicative of P limitation, as has been previously assumed for Shark Bay. We conclude that availability of P for uptake by seagrasses across Shark Bay may be highly localised and cannot be predicted from system-scale gradients ( km) of sedimentary P distributions. We suggest that P availability to seagrasses is more likely a complex function of differing nutrient inputs, rates of delivery to the plants and cycling rates.
Susan Lynn Williams
Publisher: Springer Science and Business Media LLC
Date: 15-01-2021
DOI: 10.1007/S12237-020-00886-Y
Abstract: Susan Lynn Williams (1951–2018) was an exceptional marine ecologist whose research focused broadly on the ecology of benthic nearshore environments dominated by seagrasses, seaweeds, and coral reefs. She took an empirical approach founded in techniques of physiological ecology. Susan was committed to applying her research results to ocean management through outreach to decision-makers and resource managers. Susan’s career included research throughout the USA in tropical, temperate, and polar regions, but she specialized in tropical marine ecology. Susan’s scholarship, leadership, and friendship touched many people, leading to this multi-authored paper. Susan’s scholarship was multi-faceted, and she excelled in scientific discovery, integration of scientific results, application of science for conservation, and teaching, especially as a mentor to undergraduate and graduate students and postdoctoral scholars. Susan served in a variety of leadership positions throughout her career. She embodied all facets of leadership leading by ex le, listening to others, committing to the “long haul,” maintaining trust, and creating a platform for all to shine. Susan was an important role model for women in science. Susan was also a loyal friend, maintaining friendships for many decades. Susan loved cooking and entertaining with friends. This paper provides an overview of the accomplishments of Susan in the broad categories of scholarship, leadership, and friendship.
Ocean connectivity and habitat characteristics predict population genetic structure of seagrass in an extreme tropical setting
Publisher: Wiley
Date: 07-2023
DOI: 10.1002/ECE3.10257
Abstract: Understanding patterns of gene flow and processes driving genetic differentiation is important for a broad range of conservation practices. In marine organisms, genetic differentiation among populations is influenced by a range of spatial, oceanographic, and environmental factors that are attributed to the seascape. The relative influences of these factors may vary in different locations and can be measured using seascape genetic approaches. Here, we applied a seascape genetic approach to populations of the seagrass, Thalassia hemprichii , at a fine spatial scale (~80 km) in the Kimberley coast, western Australia, a complex seascape with strong, multidirectional currents greatly influenced by extreme tidal ranges (up to 11 m, the world's largest tropical tides). We incorporated genetic data from a panel of 16 microsatellite markers, overwater distance, oceanographic data derived from predicted passive dispersal on a 2 km‐resolution hydrodynamic model, and habitat characteristics from each meadow s led. We detected significant spatial genetic structure and asymmetric gene flow, in which meadows 12–14 km apart were less connected than ones 30–50 km apart. This pattern was explained by oceanographic connectivity and differences in habitat characteristics, suggesting a combined scenario of dispersal limitation and facilitation by ocean current with local adaptation. Our findings add to the growing evidence for the key role of seascape attributes in driving spatial patterns of gene flow. Despite the potential for long‐distance dispersal, there was significant genetic structuring over small spatial scales implicating dispersal and recruitment bottlenecks and highlighting the importance of implementing local‐scale conservation and management measures.
Effects of protection from fishing on the lengths of targeted and non-targeted fish species at the Houtman Abrolhos Islands, Western Australia
Publisher: Inter-Research Science Center
Date: 29-05-2009
DOI: 10.3354/MEPS08009
Drivers of species richness and abundance of marine macrophytes on shallow tropical reefs of north‐western Australia
Publisher: Wiley
Date: 09-12-2019
DOI: 10.1111/JBI.13470
Spatial patterns in fish herbivory in a temperate Australian seagrass meadow
Publisher: Elsevier BV
Date: 07-2011
Canopy-understorey relationships are mediated by reef topography in Ecklonia radiata kelp beds
Publisher: Informa UK Limited
Date: 05-2008
Strategy for assessing impacts in ephemeral tropical seagrasses
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.MARPOLBUL.2015.10.054
Abstract: We investigated the phenology and spatial patterns in Halophila decipiens by assessing biomass, reproduction and seed density in ~400 grab s les collected across nine sites (8 to 14 m water depth) between June 2011 and December 2012. Phenology correlated with light climate which is governed by the summer monsoon (wet period). During the wet period, sedimentary seed banks prevailed, varying spatially at both broad and fine scales, presenting a source of propagules for re-colonisation following the unfavourable growing conditions of the monsoon. Spatial patterns in H. decipiens biomass following monsoon conditions were highly variable within a landscape that largely comprised potential seagrass habitat. Management strategies for H. decipiens and similar transient species must recognise the high temporal and spatial variability of these populations and be underpinned by a framework that emphasises vulnerability assessments of different life stages instead of relying solely on thresholds for standing stock at fixed reference sites.
Hydrogen sulfide intrusion in seagrasses from Shark Bay, Western Australia
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/MF12022
Abstract: Sulfides in sediments and hydrogen sulfide (H2S) intrusion in plant tissues were investigated for six species of seagrass in Shark Bay, Western Australia, at two sites with elevated salinities of 42 and 45 psu. H2S intrusion ranged from % to 100% in roots and rhizomes, indicating a high degree of sulfide intrusion in some cases, although this did not vary consistently between larger, long-lived species and smaller, less persistent species. There were significant differences in accumulation of total sulfur (TS) among species. Anatomy of rhizomes and roots showed species-specific differences in aerenchyma, the air channels that allow oxygen to diffuse down to the roots and sediments, and tissues with thickened cell walls that could present a barrier to diffusion of H2S, suggesting that morphology may influence sulfide intrusion and sulfur accumulation. Sulfide concentrations in seagrass sediments were far lower in Shark Bay than in Florida Bay, a subtropical embayment where sulfide toxicity has been implicated in seagrass dieback. Despite significant H2S intrusion into tissues of some Shark Bay seagrasses, there was no evidence of any deleterious effects in the current conditions.
Differences in trophic position among sympatric sea urchin species
Publisher: Elsevier BV
Date: 2006
Environmental influences on kelp performance across the reproductive period: an ecological trade-off between gametophyte survival and growth?
Publisher: Public Library of Science (PLoS)
Date: 03-06-2013
Reproductive synchrony in a habitat-forming kelp and its relationship with environmental conditions
Publisher: Springer Science and Business Media LLC
Date: 16-09-2013
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