ORCID Profile
0000-0002-5973-0046
Current Organisation
Consejo Superior de Investigaciones Científicas
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Natural Resource Management | Palaeoecology | Environmental Science and Management | Environmental Chemistry (incl. Atmospheric Chemistry)
Ecosystem Adaptation to Climate Change | Ecosystem Assessment and Management of Coastal and Estuarine Environments | Environmental and Natural Resource Evaluation not elsewhere classified |
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.SCITOTENV.2011.08.001
Abstract: The study of a Posidonia oceanica mat (a peat-like marine sediment) core has provided a record of changes in heavy metal abundances (Fe, Mn, Ni, Cr, Cu, Pb, Cd, Zn, As and Al) since the Mid-Holocene (last 4470yr) in Portlligat Bay (NW Mediterranean). Metal contents were determined in P. oceanica. Both, the concentration records and the results of principal components analysis showed that metal pollution in the studied bay started ca. 2800yr BP and steadily increased until present. The increase in Fe, Cu, Pb, Cd, Zn and As concentrations since ca. 2800yr BP and in particular during Greek (ca. 2680-2465cal BP) and Roman (ca. 2150-1740cal BP) times shows an early anthropogenic pollution rise in the bay, which might be associated with large- and short-scale cultural and technological development. In the last ca. 1000yr the concentrations of heavy metals, mainly derived from anthropogenic activities, have significantly increased (e.g. from ~15 to 47μg g(-1) for Pb, ~23 to 95μg g(-1) for Zn and ~8 to 228μg g(-1) for As). Our study demonstrates for the first time the uniqueness of P. oceanica meadows as long-term archives of abundances, patterns, and trends of heavy metals during the Late Holocene in Mediterranean coastal ecosystems.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 07-2021
Publisher: Copernicus GmbH
Date: 24-08-2015
Abstract: Abstract. There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha−1, with an average of 654 ± 24 Mg PIC ha−1, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of −8 ± 2 Mg PIC ha−1 per degree of latitude (general linear model, GLM p 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m−2 yr−1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr−1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrated by the comparison of carbon (PIC and POC) stocks between vegetated and adjacent un-vegetated sediments.
Publisher: Frontiers Media SA
Date: 13-12-2018
Publisher: Elsevier BV
Date: 08-2020
Publisher: Wiley
Date: 07-07-2020
DOI: 10.1111/GCB.15204
Publisher: Springer Science and Business Media LLC
Date: 08-11-2019
DOI: 10.1038/S41467-019-13126-0
Abstract: An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Publisher: Springer Science and Business Media LLC
Date: 24-06-2020
DOI: 10.1007/S10021-020-00520-9
Abstract: Tidal marshes rank among the ecosystems with the highest capacity to sequester and store organic carbon (C org ) on earth. To inform conservation of coastal vegetated ecosystems for climate change mitigation, this study investigated the factors driving variability in carbon storage. We estimated soil C org stocks in tidal marshes across temperate Western Australia and assessed differences among geomorphic settings (marine and fluvial deltas, and mid-estuary) and vegetation type ( Sarcocornia quinqueflora and Juncus kraussii ) linked to soil biogeochemistry. Soil C org stocks within fluvial and mid-estuary settings were significantly higher (209 ± 14 and 211 ± 20 Mg C org ha −1 , respectively 1-m-thick soils) than in marine counterparts (156 ± 12 Mg C org ha −1 ), which can be partially explained by higher preservation of soil C org in fluvial and mid-estuary settings rich in fine-grained ( 0.063 mm) sediments (49 ± 3% and 47 ± 4%, respectively) compared to marine settings (23 ± 4%). Soil C org stocks were not significantly different between S. quinqueflora and J. kraussii marshes (185 ± 13 and 202 ± 13 Mg C org ha −1 , respectively). The higher contribution of tidal marsh plus supratidal vegetation in fluvial (80%) and intermediate (76%) compared to marine (57%) settings further explains differences in soil C org stocks. The estimated soil C org stocks in temperate Western Australia’s tidal marshes (57 Tg C org within ~ 3000 km 2 extent) correspond to about 2% of worldwide tidal marsh soil C org stocks. The results obtained identify global drivers of soil C org storage in tidal marshes and can be used to target hot spots for climate change mitigation based on tidal marsh conservation.
Publisher: Elsevier BV
Date: 03-2023
Publisher: Elsevier BV
Date: 08-2016
Publisher: Springer Science and Business Media LLC
Date: 07-03-2019
DOI: 10.1038/S41467-019-08842-6
Abstract: Calcium carbonates (CaCO 3 ) often accumulate in mangrove and seagrass sediments. As CaCO 3 production emits CO 2 , there is concern that this may partially offset the role of Blue Carbon ecosystems as CO 2 sinks through the burial of organic carbon (C org ). A global collection of data on inorganic carbon burial rates (C inorg , 12% of CaCO 3 mass) revealed global rates of 0.8 TgC inorg yr −1 and 15–62 TgC inorg yr −1 in mangrove and seagrass ecosystems, respectively. In seagrass, CaCO 3 burial may correspond to an offset of 30% of the net CO 2 sequestration. However, a mass balance assessment highlights that the C inorg burial is mainly supported by inputs from adjacent ecosystems rather than by local calcification, and that Blue Carbon ecosystems are sites of net CaCO 3 dissolution. Hence, CaCO 3 burial in Blue Carbon ecosystems contribute to seabed elevation and therefore buffers sea-level rise, without undermining their role as CO 2 sinks.
Publisher: Wiley
Date: 11-2022
DOI: 10.1002/LNO.12268
Publisher: American Geophysical Union (AGU)
Date: 11-2019
DOI: 10.1029/2019JG005233
Publisher: Wiley
Date: 18-05-2016
Abstract: Coastal vegetated ecosystems play an important role in carbon cycling and bacterial communities inhabiting coastal sediments are responsible for the remineralization and processing of organic carbon (OC). We collected 1 m-long sediment cores in Posidonia seagrass meadows from coastal and estuarine sites in Australia that differed in their sedimentary organic and inorganic carbon, nitrogen and mud contents. The metabolic ersity of sediment heterotrophic bacterial communities was characterized at different sediment depths, based on the utilization pattern of 31 in idual carbon substrates using Biolog EcoPlates
Publisher: Oxford University Press (OUP)
Date: 31-10-2022
Abstract: The CO2-fixing enzyme Ribulose bisphosphate carboxylase-oxygenase (Rubisco) links the inorganic and organic phases of the global carbon cycle. In aquatic systems, the catalytic adaptation of algae Rubiscos has been more expansive and followed an evolutionary pathway that appears distinct to terrestrial plant Rubisco. Here, we extend this survey to differing seagrass species of the genus Posidonia to reveal how their disjunctive geographical distribution and erged phylogeny, along with their CO2 concentrating mechanisms (CCMs) effectiveness, have impacted their Rubisco kinetic properties. The Rubisco from Posidonia species showed lower carboxylation efficiencies and lower sensitivity to O2 inhibition than those measured for terrestrial C3 and C4-plant Rubiscos. Compared with the Australian Posidonia species, Rubisco from the Mediterranean Posidonia oceanica had 1.5–2-fold lower carboxylation and oxygenation efficiencies, coinciding with effective CCMs and five Rubisco large subunit amino acid substitutions. Among the Australian Posidonia species, CCM effectiveness was higher in Posidonia sinuosa and lower in the deep-living Posidonia angustifolia, likely related to the 20%–35% lower Rubisco carboxylation efficiency in P. sinuosa and the two-fold higher Rubisco content in P. angustifolia. Our results suggest that the catalytic evolution of Posidonia Rubisco has been impacted by the low CO2 availability and gas exchange properties of marine environments, but with contrasting Rubisco kinetics according to the time of ersification among the species. As a result, the relationships between maximum carboxylation rate and CO2- and O2-affinities of Posidonia Rubiscos follow an alternative path to that characteristic of terrestrial angiosperm Rubiscos.
Publisher: Springer Science and Business Media LLC
Date: 11-2021
Publisher: Wiley
Date: 15-10-2022
Publisher: Elsevier BV
Date: 2009
Publisher: American Geophysical Union (AGU)
Date: 05-2018
DOI: 10.1029/2017JG004288
Publisher: Springer Science and Business Media LLC
Date: 16-12-2019
Publisher: Springer Science and Business Media LLC
Date: 27-12-2022
Publisher: Wiley
Date: 27-06-2023
DOI: 10.1111/NPH.19084
Abstract: The response of Posidonia oceanica meadows to global warming of the Eastern Mediterranean Sea, where the increase in sea surface temperature (SST) is particularly severe, is poorly investigated. Here, we reconstructed the long‐term P. oceanica production in 60 meadows along the Greek Seas over two decades (1997–2018), using lepidochronology. We determined the effect of warming on production by reconstructing the annual and maximum (i.e. August) SST, considering the role of other production drivers related to water quality (i.e. Chl a , suspended particulate matter, Secchi depth). Grand mean (±SE) production across all sites and the study period was 48 ± 1.1 mg DW per shoot yr −1 . Production over the last two decades followed a trajectory of decrease, which was related to the concurrent increase in annual SST and SST aug . Annual SST 20°C and SST aug 26.5°C was related to production decline (GAMM, P 0.05), while the rest of the tested factors did not help explain the production pattern. Our results indicate a persistent and increasing threat for Eastern Mediterranean meadows, drawing attention to management authorities, highlighting the necessity of reducing local impacts to enhance the resilience of seagrass meadows to global change threats.
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 12-2008
Publisher: National Documentation Centre (EKT)
Date: 28-02-2014
DOI: 10.12681/MMS.621
Abstract: This synopsis focuses on the effects of climate change on Mediterranean seagrasses, and associated communities, and on the contribution of the main species, Posidonia oceanica, to the mitigation of climate change effects through its role of sequestering carbon dioxide. Whilst the regression of seagrass meadows is well documented, generally linked to anthropogenic pressures, global warming could be a cause of new significant regressions, notably linked to the introduction of exotic species, the rise of Sea-Surface Temperature (SST), and relative sea level. Seagrass communities could also be affected by climate change through the replacement of seagrass species having high structural complexity by species of lower complexity and even by opportunistic introduced species. Although it is currently very difficult to predict the consequences of these alterations and their cascade effects, two main conflicting trends in the functioning of seagrass ecosystems that could occur are acceleration of the herbivore pathway or of the detritivore pathway. The mean net primary production of the dominant species, Posidonia oceanica, is relatively high and can be estimated to range between 92.5 to 144.7 g C m-2 a-1. Around 27% of the total carbon fixed by this species enters the sedimentary pathway leading to formation, over millennia, of highly organic deposits rich in refractory carbon. At the Mediterranean scale, the sequestration rate might reach 1.09 Tg C a-1. The amount of this stored carbon is estimated to range from 71 to 273 kg C m-2, which when considered at the Mediterranean scale would represent 11 to 42% of the CO2 emissions produced by Mediterranean countries since the beginning of the Industrial Revolution. The greatest value of the P. oceanica ecosystem, in the context of mitigation of global climate change, is linked to this vast long-term carbon stock accumulated over the millennia, and therefore, efforts should be focused on preserving the meadows to keep this reservoir intact.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Wiley
Date: 20-02-2017
Publisher: Springer Science and Business Media LLC
Date: 09-05-2008
DOI: 10.1007/S00442-008-1052-8
Abstract: Trophic ecology has benefitted from the use of stable isotopes for the last three decades. However, during the last 10 years, there has been a growing awareness of the isotopic biases associated with some pre-analytical procedures that can seriously h er the interpretation of food webs. We have assessed the extent of such biases by: (1) reviewing the literature on the topic, and (2) compiling C and N isotopic values of marine invertebrates reported in the literature with the associated s le preparation protocols. The factors considered were: acid-washing, distilled water rinsing (DWR), s le type (whole in iduals or pieces of soft tissues), lipid content, and gut contents. Two-level ANOVA revealed overall large and highly significant effects of acidification for both delta(13)C values (up to 0.9 per thousand decrease) and delta(15) N values (up to 2.1 per thousand decrease in whole in idual s les, and up to 1.1 per thousand increase in tissue s les). DWR showed a weak overall effect with delta(13)C increments of 0.6 per thousand (for the entire data set) or decrements of 0.7 per thousand in delta(15) N values (for tissue s les). Gut contents showed no overall significant effect, whereas lipid extraction resulted in the greatest biases in both isotopic signatures (delta(13)C, up to -2.0 per thousand in whole in iduals delta(15)N, up to +4.3 per thousand in tissue s les). The study analyzed separately the effects of the various factors in different taxonomic groups and revealed a very high ersity in the extent and direction of the effects. Maxillopoda, Gastropoda, and Polychaeta were the classes that showed the largest isotopic shifts associated with s le preparation. Guidelines for the standardization of s le preparation protocols for isotopic analysis are proposed both for large and small marine invertebrates. Broadly, these guidelines recommend: (1) avoiding both acid washing and DWR, and (2) performing lipid extraction and gut evacuation in most cases.
Publisher: American Geophysical Union (AGU)
Date: 09-2014
DOI: 10.1002/2014GB004872
Publisher: Wiley
Date: 24-10-2017
DOI: 10.1002/LOL2.10052
Publisher: American Geophysical Union (AGU)
Date: 26-05-2023
DOI: 10.1029/2022JG007295
Abstract: Seagrass meadows are effective carbon sinks due to high primary production and sequestration in sediments. However, methane (CH 4 ) emissions can partially counteract their carbon sink capacity. Here, we measured diffusive sediment‐water and sea‐air CO 2 and CH 4 fluxes in a coastal embayment dominated by Posidonia oceanica in the Mediterranean Sea. High‐resolution timeseries observations revealed large spatial and temporal variability in CH 4 concentrations (2–36 nM). Lower sea‐air CH 4 emissions were observed in an area with dense seagrass meadows compared to patchy seagrass. A 6%−40% decrease of CH 4 concentration in the surface water around noon indicates that photosynthesis likely limits CH 4 fluxes. Sediments were the major CH 4 source as implied from radon (a natural porewater tracer) observations and evidence for methanogenesis in deeper sediments. CH 4 sediment‐water fluxes (0.1 ± 0.1–0.4 ± 0.1 μmol m −2 d −1 ) were higher than average sea‐air CH 4 emissions (0.12 ± 0.10 μmol m −2 d −1 ), suggesting that dilution and CH 4 oxidation in the water column could reduce net CH 4 fluxes into the atmosphere. Overall, relatively low sea‐air CH 4 fluxes likely represent the net emissions from subtidal seagrass habitat not influenced by allochthonous CH 4 sources. The local CH 4 emissions in P. oceanica can offset less than 1% of the carbon burial in sediments (142 ± 69 g CO 2eq m −2 yr −1 ). Combining our results with earlier observations in other seagrass meadows worldwide reveals that global CH 4 emissions only offset a small fraction ( %) of carbon sequestration in sediments from seagrass meadows.
Publisher: Springer Science and Business Media LLC
Date: 06-2023
DOI: 10.1038/S43247-023-00838-X
Abstract: The soil in terrestrial and coastal blue carbon ecosystems is an important carbon sink. National carbon inventories require accurate assessments of soil carbon in these ecosystems to aid conservation, preservation, and nature-based climate change mitigation strategies. Here we harmonise measurements from Australia’s terrestrial and blue carbon ecosystems and apply multi-scale machine learning to derive spatially explicit estimates of soil carbon stocks and the environmental drivers of variation. We find that climate and vegetation are the primary drivers of variation at the continental scale, while ecosystem type, terrain, clay content, mineralogy and nutrients drive subregional variations. We estimate that in the top 0–30 cm soil layer, terrestrial ecosystems hold 27.6 Gt (19.6–39.0 Gt), and blue carbon ecosystems 0.35 Gt (0.20–0.62 Gt). Tall open eucalypt and mangrove forests have the largest soil carbon content by area, while eucalypt woodlands and hummock grasslands have the largest total carbon stock due to the vast areas they occupy. Our findings suggest these are essential ecosystems for conservation, preservation, emissions avoidance, and climate change mitigation because of the additional co-benefits they provide.
Publisher: Springer Science and Business Media LLC
Date: 29-08-2017
DOI: 10.1038/S41598-017-10424-9
Abstract: Mangroves forests of A vicennia marina occupy about 135 km 2 in the Red Sea and represent one of the most important vegetated communities in this otherwise arid and oligotrophic region. We assessed the soil organic carbon (C org ) stocks, soil accretion rates (SAR mm y −1 ) and soil C org sequestration rates (g C org m −2 yr −1 ) in 10 mangrove sites within four locations along the Saudi coast of the Central Red Sea. Soil C org density and stock in Red Sea mangroves were among the lowest reported globally, with an average of 4 ± 0.3 mg C org cm −3 and 43 ± 5 Mg C org ha −1 (in 1 m-thick soils), respectively. Sequestration rates of C org , estimated at 3 ± 1 and 15 ± 1 g C org m −2 yr −1 for the long (millennia) and short (last century) temporal scales, respectively, were also relatively low compared to mangrove habitats from more humid bioregions. In contrast, the accretion rates of Central Red Sea mangroves soils were within the range reported for global mangrove forests. The relatively low C org sink capacity of Red Sea mangroves could be due to the extreme environmental conditions such as low rainfall, nutrient limitation and high temperature, reducing the growth rates of the mangroves and increasing soil respiration rates.
Publisher: Elsevier
Date: 2019
Publisher: Frontiers Media SA
Date: 28-02-2017
Publisher: Springer Science and Business Media LLC
Date: 09-10-2018
DOI: 10.1038/S41598-018-33182-8
Abstract: Seagrasses play an important role in climate change mitigation and adaptation, acting as natural CO 2 sinks and buffering the impacts of rising sea level. However, global estimates of organic carbon (C org ) stocks, accumulation rates and seafloor elevation rates in seagrasses are limited to a few regions, thus potentially biasing global estimates. Here we assessed the extent of soil C org stocks and accumulation rates in seagrass meadows ( Thalassia hemprichii , Enhalus acoroides , Halophila stipulacea , Thalassodendrum ciliatum and Halodule uninervis ) from Saudi Arabia. We estimated that seagrasses store 3.4 ± 0.3 kg C org m −2 in 1 m-thick soil deposits, accumulated at 6.8 ± 1.7 g C org m −2 yr −1 over the last 500 to 2,000 years. The extreme conditions in the Red Sea, such as nutrient limitation reducing seagrass growth rates and high temperature increasing soil respiration rates, may explain their relative low C org storage compared to temperate meadows. Differences in soil C org storage among habitats (i.e. location and species composition) are mainly related to the contribution of seagrass detritus to the soil C org pool, fluxes of C org from adjacent mangrove and tidal marsh ecosystems into seagrass meadows, and the amount of fine sediment particles. Seagrasses sequester annually around 0.8% of CO 2 emissions from fossil-fuels by Saudi Arabia, while buffering the impacts of sea level rise. This study contributes data from understudied regions to a growing dataset on seagrass carbon stocks and sequestration rates and further evidences that even small seagrass species store C org in coastal areas.
Publisher: Elsevier BV
Date: 09-2021
Publisher: The Royal Society
Date: 06-2018
Abstract: Macroalgae form the most extensive and productive benthic marine vegetated habitats globally but their inclusion in Blue Carbon (BC) strategies remains controversial. We review the arguments offered to reject or include macroalgae in the BC framework, and identify the challenges that have precluded macroalgae from being incorporated so far. Evidence that macroalgae support significant carbon burial is compelling. The carbon they supply to sediment stocks in angiosperm BC habitats is already included in current assessments, so that macroalgae are de facto recognized as important donors of BC. The key challenges are (i) documenting macroalgal carbon sequestered beyond BC habitat, (ii) tracing it back to source habitats, and (iii) showing that management actions at the habitat lead to increased sequestration at the sink site. These challenges apply equally to carbon exported from BC coastal habitats. Because of the large carbon sink they support, incorporation of macroalgae into BC accounting and actions is an imperative. This requires a paradigm shift in accounting procedures as well as developing methods to enable the capacity to trace carbon from donor to sink habitats in the ocean.
Publisher: Elsevier BV
Date: 05-2020
Publisher: Copernicus GmbH
Date: 15-11-2018
Abstract: Abstract. Vegetated coastal ecosystems, including tidal marshes, mangroves and seagrass meadows, are being increasingly assessed in terms of their potential for carbon dioxide sequestration worldwide. However, there is a paucity of studies that have effectively estimated the accumulation rates of sediment organic carbon (Corg), also termed blue carbon, beyond the mere quantification of Corg stocks. Here, we discuss the use of the 210Pb dating technique to determine the rate of Corg accumulation in these habitats. We review the most widely used 210Pb dating models to assess their limitations in these ecosystems, often composed of heterogeneous sediments with varying inputs of organic material, that are disturbed by natural and anthropogenic processes resulting in sediment mixing and changes in sedimentation rates or erosion. Through a range of simulations, we consider the most relevant processes that impact the 210Pb records in vegetated coastal ecosystems and evaluate how anomalies in 210Pb specific activity profiles affect sediment and Corg accumulation rates. Our results show that the discrepancy in sediment and derived Corg accumulation rates between anomalous and ideal 210Pb profiles is within 20 % if the process causing such anomalies is well understood. While these discrepancies might be acceptable for the determination of mean sediment and Corg accumulation rates over the last century, they may not always provide a reliable geochronology or historical reconstruction. Reliable estimates of Corg accumulation rates might be difficult at sites with slow sedimentation, intense mixing and/or that are affected by multiple sedimentary processes. Additional tracers or geochemical, ecological or historical data need to be used to validate the 210Pb-derived results. The framework provided in this study can be instrumental in reducing the uncertainties associated with estimates of Corg accumulation rates in vegetated coastal sediments.
Publisher: Copernicus GmbH
Date: 11-07-2022
Abstract: Abstract. Seagrass meadows provide valuable socio-ecological ecosystem services, including a key role in climate change mitigation and adaption. Understanding the natural history of seagrass meadows across environmental gradients is crucial to decipher the role of seagrasses in the global ocean. In this data collation, spatial and temporal patterns in seagrass meadow structure, biomass, production and reproduction data are presented as a function of biotic and abiotic habitat characteristics. The biological traits compiled include measures of meadow structure (e.g., percent cover and shoot density), biomass (e.g., above-ground biomass), production (e.g., shoot production), and reproduction effort (e.g., flowering intensity and seed bank density). Categorical factors include bioregion, geotype (coastal or estuarine), genera and year of s ling. This dataset contains data extracted from peer-reviewed publications published between 1975 and 2020 based on a Web of Science search, and includes 15 data variables across 12 seagrass genera. The top four most studied genera are Zostera, Thalassia, Halophila and Cymodocea (80 % of data), and the least studied genera are Phyllospadix, Amphibolis and Thalassodendron (2.3 % of data). The data hotspot bioregion is the Tropical Indo Pacific (25 % of data), whereas data for the other five bioregions are evenly spread (ranging between 13 and 16 % of total data within each bioregion). From the data compiled, 39 % related to seagrass biomass, while the least number of data were related to seagrass production (10 % of data). This data collation can inform several research fields beyond seagrass ecology, such as the development of nature-based solutions for climate change mitigation, which include readership interested in blue carbon, engineering, fisheries, global change, conservation and policy.
Publisher: Springer Science and Business Media LLC
Date: 20-05-2012
DOI: 10.1038/NGEO1477
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.MARPOLBUL.2018.01.059
Abstract: Seagrass meadows provide multiple ecosystem services, yet they are among the most threatened ecosystems on earth. Because of their role as carbon sinks, protection and restoration of seagrass meadows contribute to climate change mitigation. Blue Carbon strategies aim to enhance CO
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 10-2018
Publisher: Elsevier BV
Date: 10-2015
Publisher: Wiley
Date: 06-2023
DOI: 10.1002/ECS2.4599
Abstract: Although seagrass meadows form a relatively homogenous habitat, escarpments, which form three‐dimensional structures and originate from the erosion of seagrass peat, can provide important habitat for reef fishes. Here, we compare fish assemblages and habitat structural complexity among seagrass Posidonia australis escarpments and canopies, as well as limestone reef habitats, to understand the role of seagrass escarpments as reef fish habitat in Shark Bay, Western Australia. The total number of fish species, fish biomass, and top predator biomass were significantly higher in seagrass escarpments and reef habitats than in seagrass canopies due to lower habitat structural complexity and thus becoming suitable habitats for predators and prey in the latter. Both seagrass escarpment and reef habitats host similar assemblages of top predators and carnivorous fishes, such as Epinephelus coioides , Microcanthus strigatus , and Choerodon schoenleinii , that were absent in seagrass canopies. Seagrass escarpments provide an alternative habitat for reef fishes comparable to rocky reefs, which are limited in Shark Bay. Caves and ledges within the escarpments support 13.4 Mg of fish and 3.6 Mg of top predator species of commercial interest within the Shark Bay World Heritage Site. Additional research is needed to further understand the ecological importance of seagrass escarpments in enhancing fish biomass and bio ersity, as reproduction grounds or refuge from predators, and to investigate the role of meadow edges in ecosystem function.
Publisher: Springer Science and Business Media LLC
Date: 20-08-2018
Publisher: American Geophysical Union (AGU)
Date: 06-2021
DOI: 10.1029/2021GB006935
Abstract: Seagrass meadows rank among the most significant organic carbon (C org ) sinks on earth. We examined the variability in seagrass soil C org stocks and composition across Australia and identified the main drivers of variability, applying a spatially hierarchical approach that incorporates bioregions and geomorphic settings. Top 30 cm soil C org stocks were similar across bioregions and geomorphic settings (min‐max: 20–26 Mg C org ha −1 ), but meadows formed by large species (i.e., Amphibolis spp. and Posidonia spp.) showed higher stocks (24–29 Mg C org ha −1 ) than those formed by smaller species (e.g., Halodule, Halophila, Ruppia, Zostera, Cymodocea, and Syringodium 12–21 Mg C org ha −1 ). In temperate coastal meadows dominated by large species, soil C org stocks mainly derived from seagrass C org (72 ± 2%), while allochthonous C org dominated soil C org stocks in meadows formed by small species in temperate and tropical estuarine meadows (64 ± 5%). In temperate coastal meadows, soil C org stocks were enhanced by low hydrodynamic exposure associated with high mud and seagrass C org contents. In temperate estuarine meadows, soil C org stocks were enhanced by high contributions of seagrass C org , low to moderate solar radiation, and low human pressure. In tropical estuarine meadows formed by small species, large soil C org stocks were mainly associated with low hydrodynamic energy, low rainfall, and high solar radiation. These results showcase that bioregion and geomorphic setting are not necessarily good predictors of soil C org stocks and that site‐specific estimates based on local environmental factors are needed for Blue Carbon projects and greenhouse gases accounting purposes.
Publisher: Zenodo
Date: 2022
Publisher: Wiley
Date: 15-05-2017
DOI: 10.1002/FEE.1491
Publisher: Wiley
Date: 04-2020
DOI: 10.1002/FEE.2184
Publisher: MDPI AG
Date: 26-03-2020
DOI: 10.3390/SOILSYSTEMS4020018
Abstract: Scientists studying seagrasses typically refer to their substratum as sediment, but recently researchers have begun to refer to it as a soil. However, the logistics of s ling underwater substrata and the fragility of these ecosystems challenge their study using pedological methods. Previous studies have reported geochemical processes within the rhizosphere that are compatible with pedogenesis. Seagrass substratum accumulated over the Recent Holocene and can reach several meters in thickness, but studies about deeper layers are scarce. This study is a first attempt to find sound evidence of vertical structuring in Posidonia oceanica deposits to serve as a basis for more detailed pedological studies. A principal component analysis on X-Ray Fluorescence-elemental composition, carbonate content and organic matter content data along a 475 cm core was able to identify four main physico-chemical signals: humification, accumulation of carbonates, texture and organic matter depletion. The results revealed a highly structured deposit undergoing pedogenetical processes characteristic of soils rather than a mere accumulation of sediments. Further research is required to properly describe the substratum underneath seagrass meadows, decide between the sediment or soil nature for seagrass substrata, and for the eventual inclusion of seagrass substrata in soil classifications and the mapping of seagrass soil resources.
Publisher: Elsevier BV
Date: 03-2016
Publisher: IOP Publishing
Date: 03-2020
Abstract: Vegetated coastal ecosystems along the Red Sea and Arabian Gulf coasts of Saudi Arabia thrive in an extremely arid and oligotrophic environment, with high seawater temperatures and salinity. Mangrove, seagrass and saltmarsh ecosystems have been shown to act as efficient sinks of sediment organic carbon, earning these vegetated ecosystems the moniker ‘blue carbon’ ecosystems. However, their role as nitrogen and phosphorus (N and P) sinks remains poorly understood. In this study, we examine the capacity of blue carbon ecosystems to trap and store nitrogen and phosphorous in their sediments in the central Red Sea and Arabian Gulf. We estimated the N and P stocks (in 0.2 m thick-sediments) and accumulation rates (for the last century based on 210 Pb and for the last millennia based on 14 C) in mangrove, seagrass and saltmarsh sediments from eight locations along the coast of Saudi Arabia (81 cores in total). The N and P stocks contained in the top 20 cm sediments ranged from 61 g N m −2 in Red Sea seagrass to 265 g N m −2 in the Gulf saltmarshes and from 70 g P m −2 in Red Sea seagrass meadows and mangroves to 58 g P m −2 in the Gulf saltmarshes. The short-term N and P accumulation rates ranged from 0.09 mg N cm −2 yr −1 in Red Sea seagrass to 0.38 mg N cm −2 yr −1 in Gulf mangrove, and from 0.027 mg P cm −2 yr −1 in the Gulf seagrass to 0.092 mg P cm −2 yr −1 in Red Sea mangroves. Short-term N and P accumulation rates were up to 10-fold higher than long-term accumulation rates, highlighting increasing sequestration of N and P over the past century, likely due to anthropogenic activities such as coastal development and wastewater inputs.
Publisher: Inter-Research Science Center
Date: 13-12-2011
DOI: 10.3354/AME01543
Publisher: Copernicus GmbH
Date: 27-11-2015
DOI: 10.5194/BGD-12-18913-2015
Abstract: Abstract. Biotic and abiotic factors influence the accumulation of organic carbon (Corg) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2–4 m depth) accumulated 3 to 4-fold higher Corg stocks (averaging 6.3 kg Corg m−2) at 3 to 4-fold higher rates (12.8 g Corg m−2 yr−1) compared to meadows closer to the deep limits of distribution (at 6–8 m depth 1.8 kg Corg m−2 and 3.6 g Corg m−2 yr−1). In shallower meadows, Corg stores were mostly derived from seagrass detritus (88 % in average) compared to meadows closer to the deep limit of distribution (45 % on average). Also, sediment accumulation rates and fine-grained sediment content ( 0.125 mm) in shallower meadows (2.0 mm yr−1 and 9 %, respectively) were approximately 2-fold higher than in deeper meadows (1.2 mm yr−1 and 5 %, respectively). The Corg stocks and accumulation rates accumulated over the last 500 years in bare sediments (0.6 kg Corg m−2 and 1.2 g Corg m−2 yr−1) were 3 to 11-fold lower than in P. sinuosa meadows, while fine-grained sediment content (1 %) and seagrass detritus contribution to the Corg pool (20 %) were 8 and 3-fold lower than in Posidonia meadows, respectively. The patterns found support the hypotheses that Corg storage in seagrass soils is influenced by interactions of biological (e.g. meadow productivity, cover and density), chemical (e.g. recalcitrance of Corg stocks) and physical (e.g. hydrodynamic energy and sediment accumulation rates) factors within the meadow. We conclude that there is a need to improve global estimates of seagrass carbon storage accounting for biogeochemical factors driving variability within habitats.
Publisher: Springer Science and Business Media LLC
Date: 19-03-2018
Publisher: Elsevier BV
Date: 2009
Publisher: Frontiers Media SA
Date: 24-01-2020
Publisher: Springer Science and Business Media LLC
Date: 27-11-2018
Publisher: The Royal Society
Date: 09-2018
Abstract: Researchers are increasingly studying carbon (C) storage by natural ecosystems for climate mitigation, including coastal ‘blue carbon’ ecosystems. Unfortunately, little guidance on how to achieve robust, cost-effective estimates of blue C stocks to inform inventories exists. We use existing data (492 cores) to develop recommendations on the s ling effort required to achieve robust estimates of blue C. Using a broad-scale, spatially explicit dataset from Victoria, Australia, we applied multiple spatial methods to provide guidelines for reducing variability in estimates of soil C stocks over large areas. With a separate dataset collected across Australia, we evaluated how many s les are needed to capture variability within soil cores and the best methods for extrapolating C to 1 m soil depth. We found that 40 core s les are optimal for capturing C variance across 1000's of kilometres but higher density s ling is required across finer scales (100–200 km). Accounting for environmental variation can further decrease required s ling. The within core analyses showed that nine s les within a core capture the majority of the variability and log-linear equations can accurately extrapolate C. These recommendations can help develop standardized methods for s ling programmes to quantify soil C stocks at national scales.
Publisher: Springer Science and Business Media LLC
Date: 26-06-2017
DOI: 10.1038/NCLIMATE3326
Publisher: Elsevier BV
Date: 12-2021
Publisher: Wiley
Date: 04-05-2021
DOI: 10.1111/GCB.15642
Abstract: Australia's Great Barrier Reef (GBR) catchments include some of the world's most intact coastal wetlands comprising erse mangrove, seagrass and tidal marsh ecosystems. Although these ecosystems are highly efficient at storing carbon in marine sediments, their soil organic carbon (SOC) stocks and the potential changes resulting from climate impacts, including sea level rise are not well understood. For the first time, we estimated SOC stocks and their drivers within the range of coastal wetlands of GBR catchments using boosted regression trees (i.e. a machine learning approach and ensemble method for modelling the relationship between response and explanatory variables) and identified the potential changes in future stocks due to sea level rise. We found levels of SOC stocks of mangrove and seagrass meadows have different drivers, with climatic variables such as temperature, rainfall and solar radiation, showing significant contributions in accounting for variation in SOC stocks in mangroves. In contrast, soil type accounted for most of the variability in seagrass meadows. Total SOC stock in the GBR catchments, including mangroves, seagrass meadows and tidal marshes, is approximately 137 Tg C, which represents 9%–13% of Australia's total SOC stock while encompassing only 4%–6% of the total extent of Australian coastal wetlands. In a global context, this could represent 0.5%–1.4% of global SOC stock. Our study suggests that landward migration due to projected sea level rise has the potential to enhance carbon accumulation with total carbon gains between 0.16 and 0.46 Tg C and provides an opportunity for future restoration to enhance blue carbon.
Publisher: Elsevier BV
Date: 2023
Publisher: Inter-Research Science Center
Date: 10-02-2011
DOI: 10.3354/MEPS08955
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.
Publisher: American Chemical Society (ACS)
Date: 24-07-2020
Publisher: Springer Science and Business Media LLC
Date: 15-03-2022
DOI: 10.1038/S41467-022-29013-0
Abstract: Wildfire magnitude and frequency have greatly escalated on a global scale. Wildfire products rich in biogenic elements can enter the ocean through atmospheric and river inputs, but their contribution to marine phytoplankton production is poorly understood. Here, using geochemical paleo-reconstructions, a century-long relationship between wildfire magnitude and marine phytoplankton production is established in a fire-prone region of Kimberley coast, Australia. A positive correlation is identified between wildfire and phytoplankton production on a decadal scale. The importance of wildfire on marine phytoplankton production is statistically higher than that of tropical cyclones and rainfall, when strong El Niño Southern Oscillation coincides with the positive phase of Indian Ocean Dipole. Interdecadal chlorophyll-a variation along the Kimberley coast validates the spatial connection of this phenomenon. Findings from this study suggest that the role of additional nutrients from wildfires has to be considered when projecting impacts of global warming on marine phytoplankton production.
Publisher: Copernicus GmbH
Date: 18-01-2016
DOI: 10.5194/BG-2015-598
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), 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 (i.e. silt and clay, particle sizes μm) 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 relative high soil Corg contents with relatively low mud contents (i.e. mud-Corg saturation) together with significant allochthonous inputs of terrestrial organic matter could overall disrupt the correlation expected between soil Corg and mud contents. This study shows that mud (i.e. silt and clay content) 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).
Publisher: Springer Science and Business Media LLC
Date: 10-03-2017
DOI: 10.1038/SREP44071
Abstract: Australia’s tidal marshes have suffered significant losses but their recently recognised importance in CO 2 sequestration is creating opportunities for their protection and restoration. We compiled all available data on soil organic carbon (OC) storage in Australia’s tidal marshes (323 cores). OC stocks in the surface 1 m averaged 165.41 (SE 6.96) Mg OC ha −1 (range 14–963 Mg OC ha −1 ). The mean OC accumulation rate was 0.55 ± 0.02 Mg OC ha −1 yr −1 . Geomorphology was the most important predictor of OC stocks, with fluvial sites having twice the stock of OC as seaward sites. Australia’s 1.4 million hectares of tidal marshes contain an estimated 212 million tonnes of OC in the surface 1 m, with a potential CO 2 -equivalent value of $USD7.19 billion. Annual sequestration is 0.75 Tg OC yr −1 , with a CO 2 -equivalent value of $USD28.02 million per annum. This study provides the most comprehensive estimates of tidal marsh blue carbon in Australia, and illustrates their importance in climate change mitigation and adaptation, acting as CO 2 sinks and buffering the impacts of rising sea level. We outline potential further development of carbon offset schemes to restore the sequestration capacity and other ecosystem services provided by Australia tidal marshes.
Publisher: Elsevier BV
Date: 07-2008
Publisher: Elsevier BV
Date: 04-2022
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.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 09-2020
Publisher: Public Library of Science (PLoS)
Date: 05-09-2013
Publisher: Elsevier BV
Date: 07-2020
Publisher: IOP Publishing
Date: 02-2018
Publisher: Frontiers Media SA
Date: 31-03-2201
Publisher: Authorea, Inc.
Date: 14-12-2022
DOI: 10.22541/ESSOAR.167100373.34162103/V1
Abstract: Seagrass meadows are effective carbon sinks due to their high primary production and sequestration in sediments. However, methane (CH4) fluxes can partially counteract their carbon sink capacity. Here, we measured diffusive sediment-water and air-sea CO2 and CH4 fluxes in a coastal embayment dominated by Posidonia oceanica in the Mediterranean Sea. High resolution timeseries observations revealed large spatial and temporal variability in CH4 concentrations (2 to 36 nM). Higher emissions were observed in an area with dense seagrass meadows. A 6 − 40% decrease of CH4 concentration in the surface water around noon indicates that photosynthesis likely limits CH4 fluxes. Sediments were the major CH4 source as implied from radon (a natural porewater tracer) observations and evidence for methanogenesis in deeper sediments. CH4 sediment-water fluxes (0.1 ± 0.1 − 0.4 ± 0.1 µmol m-2 d-1) were higher than average water-air CH4 emissions (0.12 ± 0.10 µmol m-2 d-1), suggesting that dilution and CH4 oxidation in the water column could reduce net CH4 fluxes into the atmosphere. Overall, relatively low air-sea CH4 fluxes at this likely represent net emissions from subtidal seagrass habitats sites, which are not influenced by nearby allochthonous CH4 sources. The local CH4 emissions in P. oceanica offset less than 1% of the carbon burial in sediments (142 ± 69 g CO2eq m-2 yr-1). Combining our results with earlier observations in other seagrass meadows worldwide reveals that global CH4 emissions within seagrass meadows only offset a small fraction ( %) of carbon sequestration in sediments.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Copernicus GmbH
Date: 06-03-2015
Abstract: Abstract. There has been a growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the organic carbon (POC) stocks and accumulation rates and ignored the inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 402 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m sediments ranged between 3 and 1660 Mg PIC ha-1, with an average of 654 ± 24 Mg PIC ha-1, exceeding about 5 fold those of POC reported in previous studies. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of -8 ± 2 Mg PIC ha-1 degree-1 of latitude (GLM, p 0.0003). Using PIC concentration and estimates of sediment accretion in seagrass meadows, mean PIC accumulation rates in seagrass sediments is 126.3 ± 0.7 g PIC m-2 y-1. Based on the global extent of seagrass meadows (177 000 to 600 000 km2), these ecosystems globally store between 11 and 39 Pg of PIC in the top meter of sediment and accumulate between 22 and 76 Tg PIC y-1, representing a significant contribution to the carbonate dynamics of coastal areas. Despite that these high rates of carbonate accumulation imply CO2 emissions from precipitation, seagrass meadows are still strong CO2 sinks as demonstrates the comparison of carbon (POC and POC) stocks between vegetated and adjacent un-vegetated sediments.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Springer International Publishing
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 06-02-2017
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.
Publisher: Copernicus GmbH
Date: 15-08-2016
Abstract: Abstract. Biotic and abiotic factors influence the accumulation of organic carbon (Corg) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2–4 m depth) accumulated 3- to 4-fold higher Corg stocks (averaging 6.3 kg Corg m−2) at 3- to 4-fold higher rates (12.8 g Corg m−2 yr−1) compared to meadows closer to the deep limits of distribution (at 6–8 m depth 1.8 kg Corg m−2 and 3.6 g Corg m−2 yr−1). In shallower meadows, Corg stocks were mostly derived from seagrass detritus (88 % in average) compared to meadows closer to the deep limit of distribution (45 % on average). In addition, soil accumulation rates and fine-grained sediment content ( 0.125 mm) in shallower meadows (2.0 mm yr−1 and 9 %, respectively) were approximately 2-fold higher than in deeper meadows (1.2 mm yr−1 and 5 %, respectively). The Corg stocks and accumulation rates accumulated over the last 500 years in bare sediments (0.6 kg Corg m−2 and 1.2 g Corg m−2 yr−1) were 3- to 11-fold lower than in P. sinuosa meadows, while fine-grained sediment content (1 %) and seagrass detritus contribution to the Corg pool (20 %) were 8- and 3-fold lower than in Posidonia meadows, respectively. The patterns found support the hypothesis that Corg storage in seagrass soils is influenced by interactions of biological (e.g., meadow productivity, cover and density), chemical (e.g., recalcitrance of Corg stocks) and physical (e.g., hydrodynamic energy and soil accumulation rates) factors within the meadow. We conclude that there is a need to improve global estimates of seagrass carbon storage accounting for biogeochemical factors driving variability within habitats.
Publisher: Elsevier BV
Date: 08-2022
DOI: 10.1016/J.SCITOTENV.2022.155598
Abstract: There is a need for tools to determine the origin of organic matter (OM) in Blue Carbon Ecosystems (BCE) and marine sediments to (1) facilitate the implementation of Blue Carbon strategies into carbon accounting and crediting schemes and (2) decipher changes in ecosystem condition over decadal to millennial time scales and thus to understand and predict the stability of BCE in a changing world. Pyrolysis-GC-compound specific isotope analysis (Py-CSIA) is applied for the first time in marine environments and BCE research. We studied Australian mangrove, tidal marsh and seagrass sediments, in addition to potential sources of OM (Avicennia, Posidonia, Zostera, Sarcocornia, Ecklonia and Ulva species and seagrass epiphytes), to identify precursors of different biomacromolecule constituents (lignin, polysaccharides and aliphatic structures). Firstly, the link between bulk δ
Publisher: Wiley
Date: 28-01-2016
DOI: 10.1111/GCB.13195
Abstract: The study of a Posidonia australis sediment archive has provided a record of ecosystem dynamics and processes over the last 600 years in Oyster Harbour (SW Australia). Ecosystem shifts are a widespread phenomenon in coastal areas, and this study identifies baseline conditions and the time-course of ecological change (cycles, trends, resilience and thresholds of ecosystem change) under environmental stress in seagrass-dominated ecosystem. The shifts in the concentrations of chemical elements, carbonates, sediments <0.125 mm and stable carbon isotope signatures (δ(13) C) of the organic matter were detected between 1850s and 1920s, whereas the shift detected in P concentration occurred several decades later (1960s). The first degradation phase (1850s-1950s) follows the onset of European settlement in Australia and was characterized by a strong increase in sediment accumulation rates and fine-grained particles, driven primarily by enhanced run-off due to land clearance and agriculture in the catchment. About 80% of total seagrass area at Oyster Harbour was lost during the second phase of environmental degradation (1960s until present). The sharp increase in P concentration and the increasing contribution of algae and terrestrial inputs into the sedimentary organic matter pool around 1960s provides compelling evidence of the documented eutrophication of the estuary and the subsequent loss of seagrass meadows. The results presented demonstrate the power of seagrass sedimentary archives to reconstruct the trajectories of anthropogenic pressures on estuarine ecosystem and the associated regime shifts, which can be used to improve the capacity of scientists and environmental managers to understand, predict and better manage ecological change in these ecosystems.
Publisher: American Geophysical Union (AGU)
Date: 10-2022
DOI: 10.1029/2022GB007481
Abstract: Our knowledge of the factors that can influence the stock of organic carbon (OC) that is stored in the soil of seagrass meadows is evolving, and several causal effects have been used to explain the variation of stocks observed at local to national scales. To gain a global‐scale appreciation of the drivers that cause variation in soil OC stocks, we compiled data on published species‐specific traits and OC stocks from monospecific and mixed meadows at multiple geomorphological settings. Species identity was recognized as an influential driver of soil OC stocks, despite their large intraspecific variation. The most important seagrass species traits associated with OC stocks were the number of leaves per seagrass shoot, belowground biomass, leaf lifespan, aboveground biomass, leaf lignin, leaf breaking force and leaf OC plus the coastal geomorphology of the area, particularly for lagoon environments. A revised estimate of the global average soil OC stock to 20 cm depth of 15.4 Mg C ha −1 is lower than previously reported. The largest stocks were still recorded in Mediterranean seagrass meadows. Our results specifically identify Posidonia oceanica from the Mediterranean and, more generally, large and persistent species as key in providing climate regulation services, and as priority species for conservation for this specific ecosystem service.
Publisher: Springer Science and Business Media LLC
Date: 05-09-2019
DOI: 10.1038/S41467-019-11693-W
Abstract: The term Blue Carbon (BC) was first coined a decade ago to describe the disproportionately large contribution of coastal vegetated ecosystems to global carbon sequestration. The role of BC in climate change mitigation and adaptation has now reached international prominence. To help prioritise future research, we assembled leading experts in the field to agree upon the top-ten pending questions in BC science. Understanding how climate change affects carbon accumulation in mature BC ecosystems and during their restoration was a high priority. Controversial questions included the role of carbonate and macroalgae in BC cycling, and the degree to which greenhouse gases are released following disturbance of BC ecosystems. Scientists seek improved precision of the extent of BC ecosystems techniques to determine BC provenance understanding of the factors that influence sequestration in BC ecosystems, with the corresponding value of BC and the management actions that are effective in enhancing this value. Overall this overview provides a comprehensive road map for the coming decades on future research in BC science.
Publisher: Elsevier BV
Date: 04-2023
Publisher: Frontiers Media SA
Date: 29-08-2017
Publisher: American Geophysical Union (AGU)
Date: 24-01-2013
DOI: 10.1029/2012GB004296
Publisher: Springer Science and Business Media LLC
Date: 26-05-2021
DOI: 10.1038/S41598-021-90544-5
Abstract: Seagrass ecosystems rank amongst the most efficient natural carbon sinks on earth, sequestering CO 2 through photosynthesis and storing organic carbon (C org ) underneath their soils for millennia and thereby, mitigating climate change. However, estimates of C org stocks and accumulation rates in seagrass meadows (blue carbon) are restricted to few regions, and further information on spatial variability is required to derive robust global estimates. Here we studied soil C org stocks and accumulation rates in seagrass meadows across the Colombian Caribbean. We estimated that Thalassia testudinum meadows store 241 ± 118 Mg C org ha −1 (mean ± SD) in the top 1 m-thick soils, accumulated at rates of 122 ± 62 and 15 ± 7 g C org m −2 year −1 over the last ~ 70 years and up to 2000 years, respectively. The tropical climate of the Caribbean Sea and associated sediment run-off, together with the relatively high primary production of T. testudinum , influencing biotic and abiotic drivers of C org storage linked to seagrass and soil respiration rates, explains their relatively high C org stocks and accumulation rates when compared to other meadows globally. Differences in soil C org storage among Colombian Caribbean regions are largely linked to differences in the relative contribution of C org sources to the soil C org pool (seagrass, algae Halimeda tuna , mangrove and seston) and the content of soil particles 0.016 mm binding C org and enhancing its preservation. Despite the moderate areal extent of T. testudinum in the Colombian Caribbean (661 km 2 ), it sequesters around 0.3 Tg CO 2 year −1 , which is equivalent to ~ 0.4% of CO 2 emissions from fossil fuels in Colombia. This study adds data from a new region to a growing dataset on seagrass blue carbon and further explores differences in meadow C org storage based on biotic and abiotic environmental factors, while providing the basis for the implementation of seagrass blue carbon strategies in Colombia.
Publisher: Wiley
Date: 11-2022
DOI: 10.1002/LNO.12258
Abstract: Seagrass meadows composed of larger species are assumed to store larger sediment organic carbon (C org ) stocks, storing more C org in their tissues and larger leaves promoting greater burial of seagrass and non‐seagrass C org . However, the influence of species composition on sediment C org stocks remains poorly understood mainly from challenges in isolating it from confounding factors. We assessed C org stocks in seagrass biomass and sediment of four species compositions in a tropical Caribbean meadow. We hypothesized that larger species would lead to higher sediment C org stocks, within a limited geomorphic setting and time frame. Seagrass biomass and surficial and sediment profiles were collected to measure seagrass morphometrics, δ 13 C and δ 15 N, dry bulk density, C org and inorganic carbon (C inorg ) stocks, and grain size. Seagrass biomass C org stocks ranged from 0.04 to 3.7 Mg ha −1 , with higher biomass C org stocks in compositions with larger species. Surficial sediment C org and C inorg stocks (to 1.5 cm) averaged 2.6 ± 0.6 Mg C org ha −1 and 68.8 ± 14.6 Mg C inorg ha −1 , respectively, and did not vary among species compositions. Isotopic analyses revealed a ~ 50% contribution of seagrasses to surficial sediment C org in compositions with larger species, compared to a contribution of ~ 35% for those of smaller species. This study provides novel blue carbon data from an understudied region and contributes to understanding the role of seagrass species composition on sediment carbon storage.
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.SCITOTENV.2018.08.400
Abstract: The upper Spencer Gulf in South Australia hosts the world's largest single stream Pb-Zn smelter, which has caused environmental and health issues related to elevated metal concentrations in the surrounding environment. The area also has extensive seagrass meadows, occupying >4000 km
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.
Publisher: Copernicus GmbH
Date: 02-2023
Abstract: Abstract. Seagrass meadows provide valuable socio-ecological ecosystem services, including a key role in climate change mitigation and adaption. Understanding the natural history of seagrass meadows across environmental gradients is crucial to deciphering the role of seagrasses in the global ocean. In this data collation, spatial and temporal patterns in seagrass meadow structure, biomass and production data are presented as a function of biotic and abiotic habitat characteristics. The biological traits compiled include measures of meadow structure (e.g. percent cover and shoot density), biomass (e.g. above-ground biomass) and production (e.g. shoot production). Categorical factors include bioregion, geotype (coastal or estuarine), genera and year of s ling. This dataset contains data extracted from peer-reviewed publications published between 1975 and 2020 based on a Web of Science search and includes 11 data variables across 12 seagrass genera. The dataset excludes data from mesocosm and field experiments, contains 14 271 data points extracted from 390 publications and is publicly available on the PANGAEA® data repository (0.1594/PANGAEA.929968 Strydom et al., 2021). The top five most studied genera are Zostera, Thalassia, Cymodocea, Halodule and Halophila (84 % of data), and the least studied genera are Phyllospadix, Amphibolis and Thalassodendron (2.3 % of data). The data hotspot bioregion is the Tropical Indo-Pacific (25 % of data) followed by the Tropical Atlantic (21 %), whereas data for the other four bioregions are evenly spread (ranging between 13 and 15 % of total data within each bioregion). From the data compiled, 57 % related to seagrass biomass and 33 % to seagrass structure, while the least number of data were related to seagrass production (11 % of data). This data collation can inform several research fields beyond seagrass ecology, such as the development of nature-based solutions for climate change mitigation, which include readership interested in blue carbon, engineering, fisheries, global change, conservation and policy.
Publisher: American Geophysical Union (AGU)
Date: 09-2008
DOI: 10.1029/2008GL034773
Start Date: 2017
End Date: 2019
Funder: Australian Research Council
View Funded ActivityStart Date: 2017
End Date: 12-2019
Amount: $372,000.00
Funder: Australian Research Council
View Funded Activity