ORCID Profile
0000-0002-6681-8054
Current Organisations
University of New South Wales
,
Commonwealth Scientific and Industrial Research Organisation
,
University of Queensland
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Publisher: Elsevier BV
Date: 09-2016
Publisher: Frontiers Media SA
Date: 22-03-2017
Publisher: Wiley
Date: 26-03-2021
DOI: 10.1002/ECE3.7464
Abstract: Mutualism is a form of symbiosis whereby both parties benefit from the relationship. An ex le is cleaning symbiosis, which has been observed in terrestrial and marine environments. The most recognized form of marine cleaning symbiosis is that of cleaner fishes and their clients. Cleaner species set up cleaning stations on the reef, and other species seek out their services. However, it is not well understood how the presence of cleaning stations influence movements of large highly mobile species. We examined the role of cleaning stations as a driver of movement and habitat use in a mobile client species. Here, we used a combination of passive acoustic telemetry and in‐water surveys to investigate cleaning station attendance by the reef manta ray Mobula alfredi . We employed a novel approach in the form of a fine‐scale acoustic receiver array set up around a known cleaning area and tagged 42 rays. Within the array, we mapped structural features, surveyed the distribution of cleaner wrasse, and observed the habitat use of the rays. We found manta ray space use was significantly associated with blue‐streak cleaner wrasse Labroides dimidiatus distribution and hard coral substrate. Cleaning interactions dominated their habitat use at this site, taking precedence over other life history traits such as feeding and courtship. This study has demonstrated that cleaning symbiosis is a driver for highly mobile, and otherwise pelagic, species to visit inshore reef environments. We suggest that targeted and long‐term use of specific cleaning stations reflects manta rays having a long‐term memory and cognitive map of some shallow reef environments where quality cleaning is provided. We hypothesize that animals prefer cleaning sites in proximity to productive foraging regions.
Publisher: Inter-Research Science Center
Date: 10-03-2022
DOI: 10.3354/MEPS13982
Abstract: Cyclonic eddies are erse in their size, age, upwelling and behaviour, which has significant implications for fisheries production and connectivity when they interact with the continental shelf. To ascertain coastal entrainment by eddies, we compared the larval fish community of 2 contrasting cyclonic eddies in 3 depth strata (0-5, 5-50, 50-100 m), and with the adjacent shelf community. The frontal cyclonic eddy was smaller and younger than the mesoscale cyclonic eddy. A larval fish entrainment index, based on the ratio of coastal to oceanic taxa, revealed the relative abundance of coastal larvae entrained into the upper mixed layer of the frontal eddy, consistent with published numerical modelling studies of similar eddies. The frontal eddy had a high abundance of commercially important coastal taxa entrained from the inner shelf. However, the adjacent inner shelf water and putative location for frontal eddy formation had recently been displaced by the East Australian Current, resulting in the larval fish community being dominated by oceanic taxa. The spatial and temporal dynamics of coastal entrainment into the larger, older cyclonic eddy and the adjacent shelf region were revealed by mixtures of coastal and oceanic taxa in each of the depth strata. The larger cyclonic eddy had a higher biomass of zooplankton, indicating the cumulative effects of eddy age and production. Eddies which interact with the shelf enable cross-shelf mixing and may contribute to coastal fisheries.
Publisher: Oxford University Press (OUP)
Date: 26-05-2017
Abstract: Policy- and decision-makers require assessments of status and trends for marine species, habitats, and ecosystems to understand if human activities in the marine environment are sustainable, particularly in the face of global change. Central to many assessments are statistical and dynamical models of populations, communities, ecosystems, and their socioeconomic systems and management frameworks. The establishment of a national system that could facilitate the development of such model-based assessments has been identified as a priority for addressing management challenges for Australia’s marine environment. Given that most assessments require cross-scale information, in idual models cannot capture all of the spatial, temporal, biological, and socioeconomic scales that are typically needed. Coupling or integrating models across scales and domains can expand the scope for developing comprehensive and internally consistent, system-level assessments, including higher-level feedbacks in social–ecological systems. In this article, we summarize: (i) integrated modelling for marine systems currently being undertaken in Australia, (ii) methods used for integration and comparison of models, and (iii) improvements to facilitate further integration, particularly with respect to standards and specifications. We consider future needs for integrated modelling of marine social–ecological systems in Australia and provide a set of recommendations for priority focus areas in the development of a national approach to integrated modelling. These recommendations draw on—and have broader relevance for—international efforts around integrated modelling to inform decision-making for marine systems.
Publisher: Wiley
Date: 07-12-2021
DOI: 10.1111/FAF.12633
Abstract: Predicting recruitment remains a fundamental problem in fisheries science. The Mortality/Growth ratio ( M / G ) of larval fish summarizes the competing rates of M and G in relation to cohort survival and potential recruitment. The larval cohort biomass initially declines after spawning ( M G ) until transition ( M / G = 1), after which the cohort may grow in biomass ( M G ). A major challenge is to obtain routine fine‐scale measurements of M / G and integrate them over broad scales. Here, we propose the M / G size‐spectrum hypothesis, whereby the M / G ratio of larval fish is correlated with the slope ( S ) of the zooplankton size‐frequency distribution. S represents the tension between faster and more efficient growth (flatter S ) and mortality (steeper S ) among particles the size of larval fish. S is explicitly driven by the ratio of mortality to growth of zooplankton, and the range of published values of S (−0.4 to −2) is consistent with M / G ratios reported for larval fish. As S can be measured at fine and large spatial scales using towed optical plankton counters, the M / G size‐spectrum hypothesis provides a context to help quantify the recruitment potential of larval fish.
Publisher: Wiley
Date: 21-03-2017
DOI: 10.1111/FOG.12213
Publisher: Springer Science and Business Media LLC
Date: 21-10-2021
DOI: 10.1038/S41558-021-01173-9
Abstract: Projections of climate change impacts on marine ecosystems have revealed long-term declines in global marine animal biomass and unevenly distributed impacts on fisheries. Here we apply an enhanced suite of global marine ecosystem models from the Fisheries and Marine Ecosystem Model Intercomparison Project (Fish-MIP), forced by new-generation Earth system model outputs from Phase 6 of the Coupled Model Intercomparison Project (CMIP6), to provide insights into how projected climate change will affect future ocean ecosystems. Compared with the previous generation CMIP5-forced Fish-MIP ensemble, the new ensemble ecosystem simulations show a greater decline in mean global ocean animal biomass under both strong-mitigation and high-emissions scenarios due to elevated warming, despite greater uncertainty in net primary production in the high-emissions scenario. Regional shifts in the direction of biomass changes highlight the continued and urgent need to reduce uncertainty in the projected responses of marine ecosystems to climate change to help support adaptation planning.
Publisher: American Geophysical Union (AGU)
Date: 31-12-2011
DOI: 10.1029/2011JC007310
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 03-2011
Publisher: American Geophysical Union (AGU)
Date: 02-2023
DOI: 10.1029/2022JC018689
Abstract: Continental shelves are key to societal interactions with the oceans, supporting % of the world's fisheries through highly productive ecosystems. Previous research has shown that phytoplankton biomass is generally higher on the inner continental shelves, often due to increased nutrient inputs from upwelling or coastal run‐off. However, consistency in observed vertical and horizontal gradients (in abundance, biomass or size) of larger particulates, including zooplankton, on continental shelves has not been established. Using an optical plankton counter and CTD mounted on an undulating towed body, we present high‐resolution vertically resolved profiles of pelagic particle size structure across a continental shelf. Biomass was highest inshore, declining with distance from shore and with depth in the top 100 m of the water column, although the presence of frontal zones can alter this pattern. In the region adjacent to the East Australian Current (EAC), uplift generated by either the EAC interacting with the continental slope or upwelling‐favorable winds, correlated with smaller geometric mean sizes and steeper size spectrum slopes, particularly in the presence of frontal features. South of the EAC separation, the continental shelf water mass was more homogenous but still displayed the same horizontal and vertical patterns in particulate biomass and mean size. By combining our observations in a global comparison, we demonstrate consistent particulate distributions on continental shelves where the inner shelf has higher biomass with a steeper size spectrum slope compared to offshore. The highly productive inner shelf supports zooplankton communities vital to temperate ecosystems and coastal fisheries, through their consistently high biomass.
Publisher: Elsevier BV
Date: 06-2017
Publisher: Research Square Platform LLC
Date: 25-04-2022
DOI: 10.21203/RS.3.RS-1186379/V1
Abstract: For over 50 years, the conceptualisation of low-nutrient oligotrophic systems having longer food chains and thus lower energy transfer to fish than their high-nutrient eutrophic counterparts 1 has achieved the status of an ecological paradigm. However, recent global assessments indicate global fish biomass could be much higher than previously thought 2–4 , suggesting that our traditional understanding of food webs may need to be revisited. Here, we challenge the classical paradigm by exploring the role of zooplankton in food webs across the world’s oceans. Using observed zooplankton size spectra, and output from a size-spectrum model that resolves nine zooplankton groups, we conclude that food chains in oligotrophic (low-nutrient) and eutrophic (high-nutrient) systems have similar lengths. We offer a compelling hypothesis to explain this emergent pattern: self-organisation of zooplankton groups across the global productivity gradient regulates food chain length. We find that in oligotrophic systems the increased carnivory and longer food chains are offset by relatively large gelatinous filter feeders eating the dominant small phytoplankton, resulting in shorter-than-expected food chains, but decreasing food quality for fish. Our findings highlight the pivotal role zooplankton play in regulating energy transfer. Better resolution of zooplankton groups, their feeding relationships and carbon content in models will increase our ability to estimate current global fish biomass 5 , project future fish biomass under climate change 6–8 , and provide more-robust forecasts of nutrient 9 and carbon cycling 10 .
Publisher: Research Square Platform LLC
Date: 08-11-2021
DOI: 10.21203/RS.3.RS-953268/V1
Abstract: Although zooplankton are the primary energy pathway from phytoplankton to fish, we understand little about how climate change will modify zooplankton communities and their role in marine ecosystems. Using a trait-based marine ecosystem model resolving key zooplankton groups, we assess climate change impacts on zooplankton community composition and implications for marine food webs globally. We find that future oceans favour food webs increasingly dominated by carnivorous (chaetognaths, jellyfish and carnivorous copepods) and gelatinous filter-feeding zooplankton (larvaceans and salps). By providing a direct energetic pathway from small phytoplankton to fish, the rise of gelatinous filter-feeders largely offsets the increase in trophic steps between primary producers and fish from declining phytoplankton production and increasing carnivorous zooplankton. However, our results indicate that future fish communities face not only reduced carrying capacity from falling primary production, but also lower quality diets as environmental conditions increasingly favour gelatinous zooplankton.
Publisher: Springer Science and Business Media LLC
Date: 15-03-2017
Publisher: Elsevier BV
Date: 05-2007
Publisher: Springer Science and Business Media LLC
Date: 05-07-2022
DOI: 10.1038/S41467-022-30991-4
Abstract: Climate change is expected to profoundly affect key food production sectors, including fisheries and agriculture. However, the potential impacts of climate change on these sectors are rarely considered jointly, especially below national scales, which can mask substantial variability in how communities will be affected. Here, we combine socioeconomic surveys of 3,008 households and intersectoral multi-model simulation outputs to conduct a sub-national analysis of the potential impacts of climate change on fisheries and agriculture in 72 coastal communities across five Indo-Pacific countries (Indonesia, Madagascar, Papua New Guinea, Philippines, and Tanzania). Our study reveals three key findings: First, overall potential losses to fisheries are higher than potential losses to agriculture. Second, while most locations ( 2/3) will experience potential losses to both fisheries and agriculture simultaneously, climate change mitigation could reduce the proportion of places facing that double burden. Third, potential impacts are more likely in communities with lower socioeconomic status.
Publisher: Elsevier BV
Date: 03-2011
Publisher: Springer Science and Business Media LLC
Date: 21-09-2023
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.TREE.2016.12.003
Abstract: Size-based ecosystem modeling is emerging as a powerful way to assess ecosystem-level impacts of human- and environment-driven changes from in idual-level processes. These models have evolved as mechanistic explanations for observed regular patterns of abundance across the marine size spectrum hypothesized to hold from bacteria to whales. Fifty years since the first size spectrum measurements, we ask how far have we come? Although recent modeling studies capture an impressive range of sizes, complexity, and real-world applications, ecosystem coverage is still only partial. We describe how this can be overcome by unifying functional traits with size spectra (which we call functional size spectra) and highlight the key knowledge gaps that need to be filled to model ecosystems from bacteria to whales.
Publisher: Elsevier BV
Date: 10-2015
Publisher: Elsevier BV
Date: 02-2020
Publisher: Wiley
Date: 07-09-2022
DOI: 10.1111/FOG.12608
Abstract: Larval dispersal and connectivity have important implications for fisheries management, especially for species with life cycles influenced by ocean boundary currents. Giant Mud Crab ( Scylla serrata ) and Blue Swimmer Crab ( Portunus armatus ) are two estuarine portunid crabs (Family: Portunidae) that support significant commercial and recreational harvest in eastern Australia. Giant Mud Crab migrate to coastal waters to spawn, and while Blue Swimmer Crab spawn primarily within estuaries they occasionally migrate to coastal waters to spawn, followed by larval dispersal in the East Australian Current (EAC). Here, we coupled a high‐resolution oceanographic model with a Lagrangian particle tracking framework to simulate larval dispersal and determine the extent of population connectivity in this region. Our simulations indicate broad‐scale connectivity (~40–400 km), characterised by high inter‐estuary connectivity. Overall, our results suggest a north‐to‐south source‐sink structure for both species, with contributions of particles from the north ranging from 51% to 99%. Recruitment to a given estuary is dependent on the proximity of mesoscale oceanographic features of the EAC. Most notably, the EAC separation acts as a barrier to recruitment between spawning and settlement to the north/south of this region. This significantly limits interjurisdictional connectivity for these species, especially Blue Swimmer Crab, likely due to a shorter pelagic larval duration than Giant Mud Crab. Our results provide evidence to inform the assessment and management of these species.
Publisher: Elsevier BV
Date: 03-2011
Publisher: Wiley
Date: 30-03-2021
DOI: 10.1002/LOM3.10427
Publisher: Wiley
Date: 09-2015
DOI: 10.1111/FOG.12122
Publisher: Springer Science and Business Media LLC
Date: 06-2016
Publisher: Springer Science and Business Media LLC
Date: 18-03-2021
Publisher: Springer Science and Business Media LLC
Date: 23-03-2023
DOI: 10.1038/S41558-023-01630-7
Abstract: Zooplankton are the primary energy pathway from phytoplankton to fish. Yet, there is limited understanding about how climate change will modify zooplankton communities and the implications for marine food webs globally. Using a trait-based marine ecosystem model resolving key zooplankton groups, we find that future oceans, particularly in tropical regions, favour food webs increasingly dominated by carnivorous (chaetognaths, jellyfish and carnivorous copepods) and gelatinous filter-feeding zooplankton (larvaceans and salps) at the expense of omnivorous copepods and euphausiids. By providing a direct energetic pathway from small phytoplankton to fish, the rise of gelatinous filter feeders partially offsets the increase in trophic steps between primary producers and fish from declining phytoplankton biomass and increases in carnivorous zooplankton. However, future fish communities experience reduced carrying capacity from falling phytoplankton biomass and less nutritious food as environmental conditions increasingly favour gelatinous zooplankton, slightly exacerbating projected declines in small pelagic fish biomass in tropical regions by 2100.
Publisher: Research Square Platform LLC
Date: 23-09-2022
DOI: 10.21203/RS.3.RS-2048619/V1
Abstract: Anthropogenic activities threaten global bio ersity and ecosystem services. Yet, area-based conservation efforts typically target bio ersity protection whilst minimising conflict with economic activities, failing to consider ecosystem services. Here we identify priority areas that maximise both the protection of mangrove bio ersity and their ecosystem services. We reveal that despite 13.1% of the mangrove distribution being currently protected, all mangrove species are not adequately represented and many areas that provide disproportionally large ecosystem services are missed. Optimising the placement of future conservation efforts to protect 30% of global mangroves potentially safeguards an additional 16.2 billion USD of coastal property value, 6.2 million people, 1,187.9 Mt C, and 51.7 million fisher days yr − 1 . Our findings suggest that there is a pressing need for including ecosystem services in protected area design and that strategic prioritisation and coordination of mangrove conservation could provide substantial benefits to human wellbeing.
Publisher: Wiley
Date: 31-01-2022
DOI: 10.1002/LOB.10479
Publisher: Elsevier BV
Date: 06-2017
Publisher: The Royal Society
Date: 10-2023
Publisher: PeerJ
Date: 12-03-2016
DOI: 10.7287/PEERJ.PREPRINTS.1854V1
Abstract: The intensification of western boundary currents in the global ocean will potentially influence meso-scale eddy generation, and redistribute microbes and their associated ecological and biogeochemical functions. To understand eddy-induced changes in microbial community composition as well as how they control growth, we targeted the East Australian Current (EAC) region to s le microbes in a cyclonic (cold-core) eddy (CCE) and the adjacent EAC. Phototrophic and diazotrophic microbes were more erse (2 to 10 times greater Shannon index) in the CCE relative to the EAC, and the cell size distribution in the CCE was dominated (67%) by larger micro-plankton (≥ 20 µm), as opposed to pico- and nano-sized cells in the EAC. Nutrient addition experiments determined that nitrogen was the principal nutrient limiting growth in the EAC, while iron was a secondary limiting nutrient in the CCE. Among the diazotrophic community, heterotrophic NifH gene sequences dominated in the EAC and were attributable to members of the gamma-, beta-, and delta-proteobacteria, while the CCE contained both phototrophic and heterotrophic diazotrophs, including Trichodesmium , UCYN-A and gamma-proteobacteria. Daily s ling of incubation bottles following nutrient amendment captured a cascade of effects at the cellular, population and community level, indicating taxon-specific differences in the speed of response of microbes to nutrient supply. Nitrogen addition to the CCE community increased picoeukaryote chlorophyll a quotas within 24 h, suggesting that nutrient uplift by eddies causes a ‘greening’ effect as well as an increase in phytoplankton biomass. After three days in both the EAC and CCE, diatoms increased in abundance with macronutrient (N, P, Si) and iron amendment , whereas haptophytes and phototrophic dinoflagellates declined. Our results indicate that cyclonic eddies increase delivery of nitrogen to the upper ocean to potentially mitigate the negative consequences of increased stratification due to ocean warming, but also increase the biological demand for iron that is necessary to sustain the growth of large-celled phototrophs and potentially support the ersity of diazotrophs over longer time-scales.
Publisher: Springer Science and Business Media LLC
Date: 04-2022
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.TREE.2016.06.007
Abstract: Salps are barrel-shaped, gelatinous zooplankton that regularly form large swarms. They have historically been ignored because they are difficult to s le and their gelatinous body structure suggests that they are unimportant in food webs and biogeochemical cycles. We collate evidence to overturn several common misconceptions about salps that have h ered research. We show that salps play a major role in carbon sequestration and are key components of marine food webs as a food source for at least 202 species including fish, turtles, and crustaceans. The future of salps in the Anthropocene is uncertain, and therefore further research into areas such as basic rate processes and their biogeochemical impact through new and innovative laboratory and field methods is needed.
Publisher: Springer Science and Business Media LLC
Date: 15-09-2014
Publisher: Canadian Science Publishing
Date: 2023
Abstract: Climate change is altering marine ecosystems across the globe and is projected to do so for centuries to come. Marine conservation agencies can use short- and long-term projections of species-specific or ecosystem-level climate responses to inform marine conservation planning. Yet, integration of climate change adaptation, mitigation, and resilience into marine conservation planning is limited. We analysed future trajectories of climate change impacts on total consumer biomass and six key physical and biogeochemical drivers across the Northwest Atlantic Ocean to evaluate the consequences for Marine Protected Areas (MPAs) and Other Effective area-based Conservation Measures (OECMs) in Atlantic Canada. We identified climate change hotspots and refugia, where the environmental drivers are projected to change most or remain close to their current state, respectively, by mid- and end-century. We used standardized outputs from the Fisheries and Marine Ecosystem Model Intercomparison Project and the 6th Coupled Model Intercomparison Project. Our analysis revealed that, currently, no existing marine conservation areas in Atlantic Canada overlap with identified climate refugia. Most (75%) established MPAs and more than one-third (39%) of the established OECMs lie within cumulative climate hotspots. Our results provide important long-term context for adaptation and future-proofing spatial marine conservation planning in Canada and the Northwest Atlantic region.
Publisher: Frontiers Media SA
Date: 19-10-2016
Publisher: Springer Science and Business Media LLC
Date: 08-09-2020
DOI: 10.1038/S41597-020-00625-9
Abstract: Zooplankton biomass data have been collected in Australian waters since the 1930s, yet most datasets have been unavailable to the research community. We have searched archives, scanned the primary and grey literature, and contacted researchers, to collate 49187 records of marine zooplankton biomass from waters around Australia (0–60°S, 110–160°E). Many of these datasets are relatively small, but when combined, they provide years of zooplankton biomass data for Australian waters from 1932 to the present. Data have been standardised and all available metadata included. We have lodged this dataset with the Australian Ocean Data Network, allowing full public access. The Australian Zooplankton Biomass Database will be valuable for global change studies, research assessing trophic linkages, and for initialising and assessing biogeochemical and ecosystem models of lower trophic levels.
Publisher: Wiley
Date: 28-02-2023
DOI: 10.1002/LNO.12326
Abstract: Frontal eddies form on the shoreward edge of boundary currents, on average at weekly intervals and can last up to several weeks. This duration allows zooplankton production and completion of the larval stage of fish but may be too ephemeral for longer food chains with planktonic predators to establish. Therefore, frontal eddies may provide a suitable offshore nursery habitat, by entraining and retaining inner‐shelf water, preconditioned with coastal plankton and ichthyoplankton, into an upwelling favorable cyclonic eddy. Here, we briefly describe the behavior of frontal eddies formed by western boundary currents in the context of the fundamental ocean triad, which incorporates three processes for the successful reproduction of fish: nutrient enrichment, food concentration, and retention of larvae. We adapt this hypothesis for frontal eddies adjacent to the substantial fisheries production of continental shelves, creating conditions for enhanced recruitment potential of larval cohorts at a finer scale than previously considered. We review the evidence and investigations of frontal eddies in their capacity to entrain coastal water, sustain the plankton community through eddy uplift and retain distinctive coastal communities of larval fish offshore until larval development is complete. The process of frontal eddy formation is complex and such habitats are irregular yet ubiquitous, which present challenges and opportunities for their study. With the advance of ocean observing systems and integration of physical and biological s ling, frontal eddies provide a novel focus for understanding fisheries production and connectivity of coastal ecosystems.
Publisher: Wiley
Date: 28-09-2020
Publisher: Elsevier BV
Date: 03-2011
Publisher: Springer Science and Business Media LLC
Date: 30-08-2016
Abstract: Since 2008, 26 glider missions have been undertaken along the continental shelf of southeastern Australia. Typically these missions have spanned the continental shelf on the inshore edge of the East Australian Current from 29.5–33.5 ° S. This comprehensive dataset of over 33,600 CTD profiles from the surface to within 10 m of the bottom in water depths ranging 25–200 m provides new and unprecedented high resolution observations of the properties of the continental shelf waters adjacent to a western boundary current, straddling the region where it separates from the coast. The region is both physically and biologically significant, and is also in a hotspot of ocean warming. We present gridded mean fields for temperature, salinity and density, but also dissolved oxygen and chlorophyll-a fluorescence indicative of phytoplankton biomass. This data will be invaluable for understanding shelf stratification, circulation, biophysical and bio-geochemical interactions, as well as for the validation of high-resolution ocean models or serving as teaching material.
Publisher: PeerJ
Date: 25-04-2016
DOI: 10.7717/PEERJ.1973
Abstract: The intensification of western boundary currents in the global ocean will potentially influence meso-scale eddy generation, and redistribute microbes and their associated ecological and biogeochemical functions. To understand eddy-induced changes in microbial community composition as well as how they control growth, we targeted the East Australian Current (EAC) region to s le microbes in a cyclonic (cold-core) eddy (CCE) and the adjacent EAC. Phototrophic and diazotrophic microbes were more erse (2–10 times greater Shannon index) in the CCE relative to the EAC, and the cell size distribution in the CCE was dominated (67%) by larger micro-plankton $(\\geq 20\\lrm{\\mu }\\mathrm{m})$, as opposed to pico- and nano-sized cells in the EAC. Nutrient addition experiments determined that nitrogen was the principal nutrient limiting growth in the EAC, while iron was a secondary limiting nutrient in the CCE. Among the diazotrophic community, heterotrophic NifH gene sequences dominated in the EAC and were attributable to members of the gamma-, beta-, and delta-proteobacteria, while the CCE contained both phototrophic and heterotrophic diazotrophs, including Trichodesmium , UCYN-A and gamma-proteobacteria. Daily s ling of incubation bottles following nutrient amendment captured a cascade of effects at the cellular, population and community level, indicating taxon-specific differences in the speed of response of microbes to nutrient supply. Nitrogen addition to the CCE community increased picoeukaryote chlorophyll a quotas within 24 h, suggesting that nutrient uplift by eddies causes a ‘greening’ effect as well as an increase in phytoplankton biomass. After three days in both the EAC and CCE, diatoms increased in abundance with macronutrient (N, P, Si) and iron amendment, whereas haptophytes and phototrophic dinoflagellates declined. Our results indicate that cyclonic eddies increase delivery of nitrogen to the upper ocean to potentially mitigate the negative consequences of increased stratification due to ocean warming, but also increase the biological demand for iron that is necessary to sustain the growth of large-celled phototrophs and potentially support the ersity of diazotrophs over longer time-scales.
Publisher: Inter-Research Science Center
Date: 02-10-2013
DOI: 10.3354/MEPS10450
Publisher: Wiley
Date: 09-06-2021
DOI: 10.1111/JFB.14809
Abstract: The black marlin Istiompax indica is an apex marine predator and is susceptible to overfishing. The movement ecology of the species remains poorly known, particularly within the Indian Ocean, which has h ered assessment of their conservation status and fisheries management requirements. Here, we used pop‐up archival satellite tags to track I. indica movement and examine their dispersal. Forty‐nine tags were deployed off Kenya during both the north‐east (November–April) and south‐west (August–September) monsoon seasons, providing locations from every month of the year. In idual I. indica were highly mobile and track distance correlated with the duration of tag attachment. Mean track duration was 38 days and mean track distance was km. In iduals dispersed in several directions: north‐east into Somalian waters and up to northern Oman, east towards the Seychelles, and south into the Mozambique Channel. Their core habitat shifted seasonally and overlapped with areas of high productivity off Kenya, Somalia and Oman during the first half of the year. A second annual aggregation off the Kenyan coast, during August and September, did not coincide with high chlorophyll‐ a (chl‐ a ) concentrations or thermal fronts, and the drivers of the species' presence and movement from this second aggregation was unclear. We tested their habitat preferences by comparing environmental conditions at track locations to the conditions at locations along simulated tracks based on the empirical data. Observed I. indica preferred cooler water with higher chl‐ a concentrations and stayed closer to the coast than simulated tracks. The rapid and extensive dispersal of I. indica from Kenya suggests that there is likely a single stock in the Western Indian Ocean, with in iduals swimming between areas of high commercial catches off northern Somalia and Oman, and artisanal and recreational fisheries catches throughout East Africa and Mozambique.
Publisher: Wiley
Date: 21-07-2020
DOI: 10.1111/FAF.12488
Publisher: Inter-Research Science Center
Date: 26-05-2011
DOI: 10.3354/MEPS09090
Publisher: American Geophysical Union (AGU)
Date: 02-2015
DOI: 10.1002/2014JC010301
Publisher: Wiley
Date: 07-12-2022
DOI: 10.1111/FOG.12620
Abstract: Estimating demographic changes in a population requires the measurement of some minimal combination of several vital rates, including the flux of in iduals into a population, the population growth rate, in idual growth rates and mortality rates. For larval fishes, the ratio of instantaneous mortality to growth (i.e., their ‘recruitment potential’) has been used to make inferences of cohort trajectory where measures of population growth rates are not attainable. Attaining estimates of mortality and growth is an arduous task, and use of the recruitment potential metric has been limited. Here, we relate size spectra of the broader plankton community to the recruitment potential of simultaneously s led larval Pacific sardines ( Sardinops sagax ), from three voyages off eastern Australia. As the size structure of a population is determined by the ratio of mortality to growth, and there is remarkable consistency in size spectra across ecosystems, we test the hypothesis that the recruitment potential of larval fish is reflected in community‐level measures of plankton size spectra. Contrary to expectations, results from this study demonstrate a negative relationship between the slope of the plankton size spectra and the recruitment potential of larval Pacific sardine. However, we also demonstrate several other stronger relationships between recruitment potential and physical oceanographic parameters. Together, results suggest plankton size spectra are unlikely to reflect recruitment potential directly. Incorporating some size‐based aspects of the plankton community into a broader modelling framework with a range of oceanographic parameters could further our ability to determine how larval success varies across a seascape.
Publisher: Elsevier BV
Date: 11-2021
Publisher: Wiley
Date: 10-08-2021
DOI: 10.1111/ECOG.05545
Abstract: Macroecological relationships provide insights into rules that govern ecological systems. Bergmann's rule posits that members of the same clade are larger at colder temperatures. Whether temperature drives this relationship is debated because several other potential drivers covary with temperature. We conducted a near‐global comparative analysis on marine copepods (97 830 s les, 388 taxa) to test Bergmann's rule, considering other potential drivers. Supporting Bergmann's rule, we found temperature better predicted size than did latitude or oxygen, with body size decreasing by 43.9% across the temperature range (‐1.7 to 30ºC). Body size also decreased by 26.9% across the range in food availability. Our results provide strong support for Bergman's rule in copepods, but emphasises the importance of other drivers in modifying this pattern. As the world warms, smaller copepod species are likely to emerge as ‘winners', potentially reducing rates of fisheries production and carbon sequestration.
Publisher: Elsevier BV
Date: 06-2015
Publisher: Oxford University Press (OUP)
Date: 22-04-2015
Publisher: American Geophysical Union (AGU)
Date: 05-2019
DOI: 10.1029/2018JG004918
Publisher: Wiley
Date: 28-04-2020
DOI: 10.1111/FOG.12473
Publisher: Elsevier BV
Date: 11-0011
Publisher: No publisher found
Date: 2015
DOI: 10.1575/1912/7191
Publisher: Wiley
Date: 03-03-2022
Publisher: American Geophysical Union (AGU)
Date: 11-2022
DOI: 10.1029/2022GB007367
Abstract: Although zooplankton play a substantial role in the biological carbon pump and serve as a crucial link between primary producers and higher trophic level consumers, the skillful representation of zooplankton is not often a focus of ocean biogeochemical models. Systematic evaluations of zooplankton in models could improve their representation, but so far, ocean biogeochemical skill assessment of Earth system model (ESM) ensembles have not included zooplankton. Here we use a recently developed global, observationally based map of mesozooplankton biomass to assess the skill of mesozooplankton in six CMIP6 ESMs. We also employ a biome‐based assessment of the ability of these models to reproduce the observed relationship between mesozooplankton biomass and surface chlorophyll. The combined analysis found that most models were able to reasonably simulate the large regional variations in mesozooplankton biomass at the global scale. Additionally, three of the ESMs simulated a mesozooplankton‐chlorophyll relationship within the observational bounds, which we used as an emergent constraint on future mesozooplankton projections. We highlight where differences in model structure and parameters may give rise to varied mesozooplankton distributions under historic and future conditions, and the resultant wide ensemble spread in projected changes in mesozooplankton biomass. Despite differences, the strength of the mesozooplankton‐chlorophyll relationships across all models was related to the projected changes in mesozooplankton biomass globally and in regional biomes. These results suggest that improved observations of mesozooplankton and their relationship to chlorophyll will better constrain projections of climate change impacts on these important animals.
Publisher: American Geophysical Union (AGU)
Date: 28-08-2012
DOI: 10.1029/2012GL053091
Publisher: Springer Science and Business Media LLC
Date: 19-07-2022
DOI: 10.1038/S41597-022-01528-7
Abstract: Knowing the distribution of fish larvae can inform fisheries science and resource management in several ways, by: 1) providing information on spawning areas 2) identifying key areas to manage and conserve and 3) helping to understand how fish populations are affected by anthropogenic pressures, such as overfishing and climate change. With the expansion of industrial fishing activity after 1945, there was increased s ling of fish larvae to help better understand variation in fish stocks. However, large-scale larval records are rare and often unavailable. Here we digitize data from Nishikawa et al . (1985), which were collected from 1956–1981 and are near-global (50°N–50°S), seasonal distribution maps of fish larvae of 18 mainly commercial pelagic taxa of the families Scombridae, Xiphiidae, Istiophoridae, Scombrolabracidae, and Scomberesocidae. Data were collected from the Pacific, Atlantic, and Indian Oceans. We present four seasonal 1° × 1° resolution maps per taxa representing larval abundance per grid cell and highlight some of the main patterns. Data are made available as delimited text, raster, and vector files.
Publisher: Wiley
Date: 18-08-2023
DOI: 10.1002/LOL2.10350
Abstract: Pyrosomes are colonial tunicates that form gelatinous tubes and occasionally produce bioluminescent swarms. The rapid “bloom‐bust” dynamics of pyrosomes have the potential to outcompete other zooplankton, restructure marine food webs, enhance carbon export, and interfere with human activities. Pyrosomes have been recorded for at least two centuries, yet much remains unknown about their physiology, bloom mechanisms, and ecosystem impacts. Recent bloom reports prompt the question of whether frequencies or densities are increasing, and whether potential population changes are caused by ocean change. This review clarifies current information on pyrosome biology and ecology and explores apparent contradictions in habitat preferences and diel vertical migration (DVM). We posit that the dominant species, Pyrosoma atlanticum , may preferentially inhabit waters below 18°C and alter its DVM activity to maintain overall body temperature near this threshold. Expanding our knowledge of pyrosomes is needed to facilitate their inclusion in ecosystem models and forecasts of future population distributions.
Location: Australia
No related grants have been discovered for Jason Everett.