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Maria Emilia Rohr - One of the best experts on this subject based on the ideXlab platform.
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blue carbon storage capacity of temperate eelgrass Zostera Marina meadows
Global Biogeochemical Cycles, 2018Co-Authors: Marianne Holmer, Mats Björk, Maria Emilia Rohr, Julia K Baum, Katharyn E Boyer, Diana Chin, Lia Chalifour, Stephanie Cimon, Mathieu CussonAbstract:Author(s): Rohr, ME; Holmer, M; Baum, JK; Bjork, M; Chin, D; Chalifour, L; Cimon, S; Cusson, M; Dahl, M; Deyanova, D; Duffy, JE; Eklof, JS; Geyer, JK; Griffin, JN; Gullstrom, M; Hereu, CM; Hori, M; Hovel, KA; Hughes, AR; Jorgensen, P; Kiriakopolos, S; Moksnes, PO; Nakaoka, M; O'Connor, MI; Peterson, B; Reiss, K; Reynolds, PL; Rossi, F; Ruesink, J; Santos, R; Stachowicz, JJ; Tomas, F; Lee, KS; Unsworth, RKF; Bostrom, C | Abstract: ©2018. American Geophysical Union. All Rights Reserved. Despite the importance of coastal ecosystems for the global carbon budgets, knowledge of their carbon storage capacity and the factors driving variability in storage capacity is still limited. Here we provide an estimate on the magnitude and variability of carbon stocks within a widely distributed marine foundation species throughout its distribution area in temperate Northern Hemisphere. We sampled 54 eelgrass (Zostera Marina) meadows, spread across eight ocean margins and 36° of latitude, to determine abiotic and biotic factors influencing organic carbon (Corg) stocks in Zostera Marina sediments. The Corg stocks (integrated over 25-cm depth) showed a large variability and ranged from 318 to 26,523 g C/m2 with an average of 2,721 g C/m2. The projected Corg stocks obtained by extrapolating over the top 1 m of sediment ranged between 23.1 and 351.7 Mg C/ha, which is in line with estimates for other seagrasses and other blue carbon ecosystems. Most of the variation in Corg stocks was explained by five environmental variables (sediment mud content, dry density and degree of sorting, and salinity and water depth), while plant attributes such as biomass and shoot density were less important to Corg stocks. Carbon isotopic signatures indicated that at most sites l50% of the sediment carbon is derived from seagrass, which is lower than reported previously for seagrass meadows. The high spatial carbon storage variability urges caution in extrapolating carbon storage capacity between geographical areas as well as within and between seagrass species.
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blue carbon storage capacity of temperate eelgrass Zostera Marina meadows
Global Biogeochemical Cycles, 2018Co-Authors: Marianne Holmer, Mats Björk, Maria Emilia Rohr, Julia K Baum, Katharyn E Boyer, Diana Chin, Lia Chalifour, Stephanie Cimon, Mathieu CussonAbstract:Author(s): Rohr, ME; Holmer, M; Baum, JK; Bjork, M; Chin, D; Chalifour, L; Cimon, S; Cusson, M; Dahl, M; Deyanova, D; Duffy, JE; Eklof, JS; Geyer, JK; Griffin, JN; Gullstrom, M; Hereu, CM; Hori, M; Hovel, KA; Hughes, AR; Jorgensen, P; Kiriakopolos, S; Moksnes, PO; Nakaoka, M; O'Connor, MI; Peterson, B; Reiss, K; Reynolds, PL; Rossi, F; Ruesink, J; Santos, R; Stachowicz, JJ; Tomas, F; Lee, KS; Unsworth, RKF; Bostrom, C | Abstract: Despite the importance of coastal ecosystems for the global carbon budgets, knowledge of their carbon storage capacity and the factors driving variability in storage capacity is still limited. Here we provide an estimate on the magnitude and variability of carbon stocks within a widely distributed marine foundation species throughout its distribution area in temperate Northern Hemisphere. We sampled 54 eelgrass (Zostera Marina) meadows, spread across eight ocean margins and 36° of latitude, to determine abiotic and biotic factors influencing organic carbon (Corg) stocks in Zostera Marina sediments. The Corg stocks (integrated over 25-cm depth) showed a large variability and ranged from 318 to 26,523ngnC/m2 with an average of 2,721ngnC/m2. The projected Corg stocks obtained by extrapolating over the top 1nm of sediment ranged between 23.1 and 351.7nMgnC/ha, which is in line with estimates for other seagrasses and other blue carbon ecosystems. Most of the variation in Corg stocks was explained by five environmental variables (sediment mud content, dry density and degree of sorting, and salinity and water depth), while plant attributes such as biomass and shoot density were less important to Corg stocks. Carbon isotopic signatures indicated that at most sites l50% of the sediment carbon is derived from seagrass, which is lower than reported previously for seagrass meadows. The high spatial carbon storage variability urges caution in extrapolating carbon storage capacity between geographical areas as well as within and between seagrass species.
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blue carbon stocks in baltic sea eelgrass Zostera Marina meadows
Biogeosciences, 2016Co-Authors: Christoffer Boström, Maria Emilia Rohr, Paula Canalverges, Marianne HolmerAbstract:Abstract. Although seagrasses cover only a minor fraction of the ocean seafloor, their carbon sink capacity accounts for nearly one-fifth of the total oceanic carbon burial and thus play a critical structural and functional role in many coastal ecosystems. We sampled 10 eelgrass (Zostera Marina) meadows in Finland and 10 in Denmark to explore seagrass carbon stocks (Corg stock) and carbon accumulation rates (Corg accumulation) in the Baltic Sea area. The study sites represent a gradient from sheltered to exposed locations in both regions to reflect expected minimum and maximum stocks and accumulation. The Corg stock integrated over the top 25 cm of the sediment averaged 627 g C m−2 in Finland, while in Denmark the average Corg stock was over 6 times higher (4324 g C m−2). A conservative estimate of the total organic carbon pool in the regions ranged between 6.98 and 44.9 t C ha−1. Our results suggest that the Finnish eelgrass meadows are minor carbon sinks compared to the Danish meadows, and that majority of the Corg produced in the Finnish meadows is exported. Our analysis further showed that > 40 % of the variation in the Corg stocks was explained by sediment characteristics, i.e. dry density, porosity and silt content. In addition, our analysis show that the root : shoot ratio of Z. Marina explained > 12 % and the contribution of Z. Marina detritus to the sediment surface Corg pool explained > 10 % of the variation in the Corg stocks. The mean monetary value for the present carbon storage and carbon sink capacity of eelgrass meadows in Finland and Denmark, were 281 and 1809 EUR ha−1, respectively. For a more comprehensive picture of seagrass carbon storage capacity, we conclude that future blue carbon studies should, in a more integrative way, investigate the interactions between sediment biogeochemistry, seascape structure, plant species architecture and the hydrodynamic regime.
Marianne Holmer - One of the best experts on this subject based on the ideXlab platform.
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blue carbon storage capacity of temperate eelgrass Zostera Marina meadows
Global Biogeochemical Cycles, 2018Co-Authors: Marianne Holmer, Mats Björk, Maria Emilia Rohr, Julia K Baum, Katharyn E Boyer, Diana Chin, Lia Chalifour, Stephanie Cimon, Mathieu CussonAbstract:Author(s): Rohr, ME; Holmer, M; Baum, JK; Bjork, M; Chin, D; Chalifour, L; Cimon, S; Cusson, M; Dahl, M; Deyanova, D; Duffy, JE; Eklof, JS; Geyer, JK; Griffin, JN; Gullstrom, M; Hereu, CM; Hori, M; Hovel, KA; Hughes, AR; Jorgensen, P; Kiriakopolos, S; Moksnes, PO; Nakaoka, M; O'Connor, MI; Peterson, B; Reiss, K; Reynolds, PL; Rossi, F; Ruesink, J; Santos, R; Stachowicz, JJ; Tomas, F; Lee, KS; Unsworth, RKF; Bostrom, C | Abstract: ©2018. American Geophysical Union. All Rights Reserved. Despite the importance of coastal ecosystems for the global carbon budgets, knowledge of their carbon storage capacity and the factors driving variability in storage capacity is still limited. Here we provide an estimate on the magnitude and variability of carbon stocks within a widely distributed marine foundation species throughout its distribution area in temperate Northern Hemisphere. We sampled 54 eelgrass (Zostera Marina) meadows, spread across eight ocean margins and 36° of latitude, to determine abiotic and biotic factors influencing organic carbon (Corg) stocks in Zostera Marina sediments. The Corg stocks (integrated over 25-cm depth) showed a large variability and ranged from 318 to 26,523 g C/m2 with an average of 2,721 g C/m2. The projected Corg stocks obtained by extrapolating over the top 1 m of sediment ranged between 23.1 and 351.7 Mg C/ha, which is in line with estimates for other seagrasses and other blue carbon ecosystems. Most of the variation in Corg stocks was explained by five environmental variables (sediment mud content, dry density and degree of sorting, and salinity and water depth), while plant attributes such as biomass and shoot density were less important to Corg stocks. Carbon isotopic signatures indicated that at most sites l50% of the sediment carbon is derived from seagrass, which is lower than reported previously for seagrass meadows. The high spatial carbon storage variability urges caution in extrapolating carbon storage capacity between geographical areas as well as within and between seagrass species.
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blue carbon storage capacity of temperate eelgrass Zostera Marina meadows
Global Biogeochemical Cycles, 2018Co-Authors: Marianne Holmer, Mats Björk, Maria Emilia Rohr, Julia K Baum, Katharyn E Boyer, Diana Chin, Lia Chalifour, Stephanie Cimon, Mathieu CussonAbstract:Author(s): Rohr, ME; Holmer, M; Baum, JK; Bjork, M; Chin, D; Chalifour, L; Cimon, S; Cusson, M; Dahl, M; Deyanova, D; Duffy, JE; Eklof, JS; Geyer, JK; Griffin, JN; Gullstrom, M; Hereu, CM; Hori, M; Hovel, KA; Hughes, AR; Jorgensen, P; Kiriakopolos, S; Moksnes, PO; Nakaoka, M; O'Connor, MI; Peterson, B; Reiss, K; Reynolds, PL; Rossi, F; Ruesink, J; Santos, R; Stachowicz, JJ; Tomas, F; Lee, KS; Unsworth, RKF; Bostrom, C | Abstract: Despite the importance of coastal ecosystems for the global carbon budgets, knowledge of their carbon storage capacity and the factors driving variability in storage capacity is still limited. Here we provide an estimate on the magnitude and variability of carbon stocks within a widely distributed marine foundation species throughout its distribution area in temperate Northern Hemisphere. We sampled 54 eelgrass (Zostera Marina) meadows, spread across eight ocean margins and 36° of latitude, to determine abiotic and biotic factors influencing organic carbon (Corg) stocks in Zostera Marina sediments. The Corg stocks (integrated over 25-cm depth) showed a large variability and ranged from 318 to 26,523ngnC/m2 with an average of 2,721ngnC/m2. The projected Corg stocks obtained by extrapolating over the top 1nm of sediment ranged between 23.1 and 351.7nMgnC/ha, which is in line with estimates for other seagrasses and other blue carbon ecosystems. Most of the variation in Corg stocks was explained by five environmental variables (sediment mud content, dry density and degree of sorting, and salinity and water depth), while plant attributes such as biomass and shoot density were less important to Corg stocks. Carbon isotopic signatures indicated that at most sites l50% of the sediment carbon is derived from seagrass, which is lower than reported previously for seagrass meadows. The high spatial carbon storage variability urges caution in extrapolating carbon storage capacity between geographical areas as well as within and between seagrass species.
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blue carbon stocks in baltic sea eelgrass Zostera Marina meadows
Biogeosciences, 2016Co-Authors: Christoffer Boström, Maria Emilia Rohr, Paula Canalverges, Marianne HolmerAbstract:Abstract. Although seagrasses cover only a minor fraction of the ocean seafloor, their carbon sink capacity accounts for nearly one-fifth of the total oceanic carbon burial and thus play a critical structural and functional role in many coastal ecosystems. We sampled 10 eelgrass (Zostera Marina) meadows in Finland and 10 in Denmark to explore seagrass carbon stocks (Corg stock) and carbon accumulation rates (Corg accumulation) in the Baltic Sea area. The study sites represent a gradient from sheltered to exposed locations in both regions to reflect expected minimum and maximum stocks and accumulation. The Corg stock integrated over the top 25 cm of the sediment averaged 627 g C m−2 in Finland, while in Denmark the average Corg stock was over 6 times higher (4324 g C m−2). A conservative estimate of the total organic carbon pool in the regions ranged between 6.98 and 44.9 t C ha−1. Our results suggest that the Finnish eelgrass meadows are minor carbon sinks compared to the Danish meadows, and that majority of the Corg produced in the Finnish meadows is exported. Our analysis further showed that > 40 % of the variation in the Corg stocks was explained by sediment characteristics, i.e. dry density, porosity and silt content. In addition, our analysis show that the root : shoot ratio of Z. Marina explained > 12 % and the contribution of Z. Marina detritus to the sediment surface Corg pool explained > 10 % of the variation in the Corg stocks. The mean monetary value for the present carbon storage and carbon sink capacity of eelgrass meadows in Finland and Denmark, were 281 and 1809 EUR ha−1, respectively. For a more comprehensive picture of seagrass carbon storage capacity, we conclude that future blue carbon studies should, in a more integrative way, investigate the interactions between sediment biogeochemistry, seascape structure, plant species architecture and the hydrodynamic regime.
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Eelgrass (Zostera Marina) food web structure in different environmental settings
PLoS ONE, 2016Co-Authors: Jonas Thormar, Susanne Baden, Harald Hasler-sheetal, Christoffer Boström, Birgit Olesen, Jonas Ribergaard Rasmussen, Carl Johan Svensson, Kevin Kuhlmann Clausen, Dorte Krause-jensen, Marianne HolmerAbstract:This study compares the structure of eelgrass (Zostera Marina L.) meadows and associated food webs in two eelgrass habitats in Denmark, differing in exposure, connection to the open sea, nutrient enrichment and water transparency. Meadow structure strongly reflected the environmental conditions in each habitat. The eutrophicated, protected site had higher biomass of filamentous algae, lower eelgrass biomass and shoot density, longer and narrower leaves, and higher above to below ground biomass ratio compared to the less nutrient-enriched and more exposed site. The faunal community composition and food web structure also differed markedly between sites with the eutrophicated, enclosed site having higher biomass of consumers and less complex food web. These relationships resulted in a column shaped biomass distribution of the consumers at the eutrophicated site whereas the less nutrient-rich site showed a pyramidal biomass distribution of consumers coupled with a more diverse consumer community. The differences in meadow and food web structure of the two seagrass habitats, suggest how physical setting may shape ecosystem response and resilience to anthropogenic pressure. We encourage larger, replicated studies to further disentangle the effects of different environmental variables on seagrass food web structure.
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sulfide intrusion and detoxification in the seagrass Zostera Marina
PLOS ONE, 2015Co-Authors: Harald Haslersheetal, Marianne HolmerAbstract:Gaseous sulfide intrusion into seagrasses growing in sulfidic sediments causes little or no harm to the plant, indicating the presence of an unknown sulfide tolerance or detoxification mechanism. We assessed such mechanism in the seagrass Zostera Marina in the laboratory and in the field with scanning electron microscopy coupled to energy dispersive X-ray spectroscopy, chromatographic and spectrophotometric methods, and stable isotope tracing coupled with a mass balance of sulfur compounds. We found that Z. Marina detoxified gaseous sediment-derived sulfide through incorporation and that most of the detoxification occurred in underground tissues, where sulfide intrusion was greatest. Elemental sulfur was a major detoxification compound, precipitating on the inner wall of the aerenchyma of underground tissues. Sulfide was metabolized into thiols and entered the plant sulfur metabolism as well as being stored as sulfate throughout the plant. We conclude that avoidance of sulfide exposure by reoxidation of sulfide in the rhizosphere or aerenchyma and tolerance of sulfide intrusion by incorporation of sulfur in the plant are likely major survival strategies of seagrasses in sulfidic sediments.
Thorsten B H Reusch - One of the best experts on this subject based on the ideXlab platform.
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transcriptomic resilience to global warming in the seagrass Zostera Marina a marine foundation species
Proceedings of the National Academy of Sciences of the United States of America, 2011Co-Authors: Susanne U Franssen, Nina Bergmann, Gidon Winters, Ulrich C Klostermeier, Philip Rosenstiel, Erich Bornbergbauer, Thorsten B H ReuschAbstract:Large-scale transcription profiling via direct cDNA sequencing provides important insights as to how foundation species cope with increasing climatic extremes predicted under global warming. Species distributed along a thermal cline, such as the ecologically important seagrass Zostera Marina, provide an opportunity to assess temperature effects on gene expression as a function of their long-term adaptation to heat stress. We exposed a southern and northern European population of Zostera Marina from contrasting thermal environments to a realistic heat wave in a common-stress garden. In a fully crossed experiment, eight cDNA libraries, each comprising ∼125 000 reads, were obtained during and after a simulated heat wave, along with nonstressed control treatments. Although gene-expression patterns during stress were similar in both populations and were dominated by classical heat-shock proteins, transcription profiles diverged after the heat wave. Gene-expression patterns in southern genotypes returned to control values immediately, but genotypes from the northern site failed to recover and revealed the induction of genes involved in protein degradation, indicating failed metabolic compensation to high sea-surface temperature. We conclude that the return of gene-expression patterns during recovery provides critical information on thermal adaptation in aquatic habitats under climatic stress. As a unifying concept for ecological genomics, we propose transcriptomic resilience, analogous to ecological resilience, as an important measure to predict the tolerance of individuals and hence the fate of local populations in the face of global warming.
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importance of genetic diversity in eelgrass Zostera Marina for its resilience to global warming
Marine Ecology Progress Series, 2008Co-Authors: Anneli Ehlers, Boris Worm, Thorsten B H ReuschAbstract:Effects of global warming on marine ecosystems are far less understood than they are in terrestrial environments. Macrophyte-based coastal ecosystems are particularly vulnerable to global warming, because they often lack species redun- dancy. We tested whether summer heat waves have negative effects on an ecologically important eco- system engineer, the eelgrass Zostera Marina L., and whether high genotypic diversity may provide re- silience in the face of climatic extremes. In a meso- cosm experiment, we manipulated genotypic diver- sity of eelgrass patches fully crossed with water temperature (control vs. temperature stress) over 5 mo. We found a strong negative effect of warming and a positive effect of genotypic diversity on shoot densities of eelgrass. These results suggest that eel- grass meadows and associated ecosystem services will be negatively affected by predicted increases in summer temperature extremes. Genotypic diver- sity may provide critical response diversity for main- taining seagrass ecosystem functioning, and for adaptation to environmental change.
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genome scans detect consistent divergent selection among subtidal vs intertidal populations of the marine angiosperm Zostera Marina
Molecular Ecology, 2007Co-Authors: Katharina Oetjen, Thorsten B H ReuschAbstract:Genome scans are a powerful tool to detect natural selection in natural populations among a larger sample of marker loci. We used replicated habitat comparisons to search for consistent signals of selection among contrasting populations of the seagrass Zostera Marina, a marine flowering plant with important ecological functions. We compared two different habitat types in the North Frisian Wadden Sea, either permanently submerged (subtidal) or subjected to aerial exposure (intertidal). In three independent population pairs, each consisting of one tidal creek and one tidal flat population each, we carried out a genome scan with 14 expressed sequence tag (EST)-derived microsatellites situated in 5'- or 3'-untranslated regions of putative genes, in addition to 11 anonymous genomic microsatellites. By using two approaches for outlier identification, one anonymous and two EST-derived microsatellites showed population differentiation patterns not consistent with neutrality. These microsatellites were detected in several parallel population comparisons, suggesting that they are under diverging selection. One of these loci is linked to a putative nodulin gene, which is responsible for water channelling across cellular membranes, suggesting a functional link of the observed genetic divergence with habitat characteristics.
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housekeeping gene selection for quantitative real time pcr assays in the seagrass Zostera Marina subjected to heat stress
Limnology and Oceanography-methods, 2006Co-Authors: Vanessa Ransbotyn, Thorsten B H ReuschAbstract:In light of increasing sea surface temperatures, quantifying the expression of stress-inducible genes in coastal organisms is an important topic of marine molecular ecology and evolution. As a prerequisite for quantitative realtime PCR (QPCR) assays, we tested the suitability of 12 candidate housekeeping genes (HKGs) for normalization of messenger RNA abundance and quality in the ecologically important seagrass species Zostera Marina. In comparing several algorithms used to identify appropriate HKGs, two approaches using reciprocal cross-validation among a larger group of HKG candidates implemented in geNorm or NormFinder yielded largely consistent results. Using these approaches, 3 HKG candidates were selected that are stable alone or in combination in the target tissue (leaf) with respect to the imposed temperature stress treatments (TATA box binding protein, translation elongation factor, eukaryotic initiation factor 4A). Example calculations revealed spurious gene expression changes of a factor of 2 in hypothetical target genes when using less stable HKGs as reference for standardization. These results highlight the need for devoting considerable effort to selecting appropriate HKGs for normalization of QPCR data before performing experiments with the target genes.
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north atlantic phylogeography and large scale population differentiation of the seagrass Zostera Marina l
Molecular Ecology, 2004Co-Authors: Jeanine L Olsen, Christoffer Boström, Hartvig Christie, Thorsten B H Reusch, Wytze T Stam, James A Coyer, Martin R Billingham, Elizabeth Calvert, Stephen Granger, Richard La LumiereAbstract:As the most widespread seagrass in temperate waters of the Northern Hemisphere, Zostera Marina provides a unique opportunity to investigate the extent to which the historical legacy of the last glacial maximum (LGM18 000–10 000 years BP ) is detectable in modern population genetic structure. We used sequences from the nuclear rDNA–internal transcribed spacer (ITS) and chloroplast mat K-intron, and nine microsatellite loci to survey 49 populations (> 2000 individuals) from throughout the species’ range. Minimal sequence variation between Pacific and Atlantic populations combined with biogeographical groupings derived from the microsatellite data, suggest that the trans -Arctic connection is currently open. The east Pacific and west Atlantic are more connected than either is to the east Atlantic. Allelic richness was almost two-fold higher in the Pacific. Populations from putative Atlantic refugia now represent the southern edges of the distribution and are not genetically diverse. Unexpectedly, the highest allelic diversity was observed in the North Sea–Wadden Sea–southwest Baltic region. Except for the Mediterranean and Black Seas, significant isolation-by-distance was found from ~150 to 5000 km. A transition from weak to strong isolation-by-distance occurred at ~150 km among northern European populations suggesting this scale as the natural limit for dispersal within the metapopulation. Links between historical and contemporary processes are discussed in terms of the projected effects of climate change on coastal marine plants. The identification of a high genetic diversity hotspot in Northern Europe provides a basis for restoration decisions.
Mathieu Cusson - One of the best experts on this subject based on the ideXlab platform.
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blue carbon storage capacity of temperate eelgrass Zostera Marina meadows
Global Biogeochemical Cycles, 2018Co-Authors: Marianne Holmer, Mats Björk, Maria Emilia Rohr, Julia K Baum, Katharyn E Boyer, Diana Chin, Lia Chalifour, Stephanie Cimon, Mathieu CussonAbstract:Author(s): Rohr, ME; Holmer, M; Baum, JK; Bjork, M; Chin, D; Chalifour, L; Cimon, S; Cusson, M; Dahl, M; Deyanova, D; Duffy, JE; Eklof, JS; Geyer, JK; Griffin, JN; Gullstrom, M; Hereu, CM; Hori, M; Hovel, KA; Hughes, AR; Jorgensen, P; Kiriakopolos, S; Moksnes, PO; Nakaoka, M; O'Connor, MI; Peterson, B; Reiss, K; Reynolds, PL; Rossi, F; Ruesink, J; Santos, R; Stachowicz, JJ; Tomas, F; Lee, KS; Unsworth, RKF; Bostrom, C | Abstract: ©2018. American Geophysical Union. All Rights Reserved. Despite the importance of coastal ecosystems for the global carbon budgets, knowledge of their carbon storage capacity and the factors driving variability in storage capacity is still limited. Here we provide an estimate on the magnitude and variability of carbon stocks within a widely distributed marine foundation species throughout its distribution area in temperate Northern Hemisphere. We sampled 54 eelgrass (Zostera Marina) meadows, spread across eight ocean margins and 36° of latitude, to determine abiotic and biotic factors influencing organic carbon (Corg) stocks in Zostera Marina sediments. The Corg stocks (integrated over 25-cm depth) showed a large variability and ranged from 318 to 26,523 g C/m2 with an average of 2,721 g C/m2. The projected Corg stocks obtained by extrapolating over the top 1 m of sediment ranged between 23.1 and 351.7 Mg C/ha, which is in line with estimates for other seagrasses and other blue carbon ecosystems. Most of the variation in Corg stocks was explained by five environmental variables (sediment mud content, dry density and degree of sorting, and salinity and water depth), while plant attributes such as biomass and shoot density were less important to Corg stocks. Carbon isotopic signatures indicated that at most sites l50% of the sediment carbon is derived from seagrass, which is lower than reported previously for seagrass meadows. The high spatial carbon storage variability urges caution in extrapolating carbon storage capacity between geographical areas as well as within and between seagrass species.
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blue carbon storage capacity of temperate eelgrass Zostera Marina meadows
Global Biogeochemical Cycles, 2018Co-Authors: Marianne Holmer, Mats Björk, Maria Emilia Rohr, Julia K Baum, Katharyn E Boyer, Diana Chin, Lia Chalifour, Stephanie Cimon, Mathieu CussonAbstract:Author(s): Rohr, ME; Holmer, M; Baum, JK; Bjork, M; Chin, D; Chalifour, L; Cimon, S; Cusson, M; Dahl, M; Deyanova, D; Duffy, JE; Eklof, JS; Geyer, JK; Griffin, JN; Gullstrom, M; Hereu, CM; Hori, M; Hovel, KA; Hughes, AR; Jorgensen, P; Kiriakopolos, S; Moksnes, PO; Nakaoka, M; O'Connor, MI; Peterson, B; Reiss, K; Reynolds, PL; Rossi, F; Ruesink, J; Santos, R; Stachowicz, JJ; Tomas, F; Lee, KS; Unsworth, RKF; Bostrom, C | Abstract: Despite the importance of coastal ecosystems for the global carbon budgets, knowledge of their carbon storage capacity and the factors driving variability in storage capacity is still limited. Here we provide an estimate on the magnitude and variability of carbon stocks within a widely distributed marine foundation species throughout its distribution area in temperate Northern Hemisphere. We sampled 54 eelgrass (Zostera Marina) meadows, spread across eight ocean margins and 36° of latitude, to determine abiotic and biotic factors influencing organic carbon (Corg) stocks in Zostera Marina sediments. The Corg stocks (integrated over 25-cm depth) showed a large variability and ranged from 318 to 26,523ngnC/m2 with an average of 2,721ngnC/m2. The projected Corg stocks obtained by extrapolating over the top 1nm of sediment ranged between 23.1 and 351.7nMgnC/ha, which is in line with estimates for other seagrasses and other blue carbon ecosystems. Most of the variation in Corg stocks was explained by five environmental variables (sediment mud content, dry density and degree of sorting, and salinity and water depth), while plant attributes such as biomass and shoot density were less important to Corg stocks. Carbon isotopic signatures indicated that at most sites l50% of the sediment carbon is derived from seagrass, which is lower than reported previously for seagrass meadows. The high spatial carbon storage variability urges caution in extrapolating carbon storage capacity between geographical areas as well as within and between seagrass species.
Robert J Orth - One of the best experts on this subject based on the ideXlab platform.
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biotic dispersal in eelgrass Zostera Marina
Marine Ecology Progress Series, 2012Co-Authors: Sarah E Sumoski, Robert J OrthAbstract:Dispersal is a critical process in the life history of nearly all plant species and can be facili - tated by both abiotic and biotic mechanisms. Despite an abundance of vertebrate fauna utilizing seagrass meadows as a feeding area and thus capable of consuming and excreting seeds, little work has been conducted on biotic seed dispersal mechanisms. The objectives of this study were to (1) determine whether seeds of the seagrass Zostera Marina could pass through the digestive systems of resident and tran - sient vertebrates of a seagrass bed and remain viable and (2) determine seed retention times in the guts of each species to estimate dispersal distances of Z. ma- rina seeds by vertebrate dispersers. Excretion and germination rates of consumed seeds for 3 fish species (Fundulus heteroclitus,Sphoeroides maculatus,Lagodon rhomboides), 1 turtle species (Malaclemys terrapin) and 1 waterfowl species (Aythya affinis) showed Z. Marina seeds could survive passage through spe- cies' digestive systems and successfully germinate. Excretion rates were generally highest for F. hetero- clitus, S. maculatus, and M. terrapin, lowest for A. affi- nis, and moderate for L. rhomboides. Analyses sug - gest seeds were significantly affected by species' digestive tracts. Maximum dispersal distances are es- timated to be 200, 60, 1500, and 19 500 m for F. hetero- clitus, L. rhomboides, M. terrapin, and A. affinis, re- spectively. Data here provide strong evidence that biotic dispersal can occur in Z. Marina, and biotically transported seeds can be dispersed to isolated areas unlikely to receive seeds via abiotic mechanisms. Bio - tic dispersal may rival or exceed abiotic mechanisms. Future seagrass dispersal models should incorporate biotic dispersal as a seed transport mechanism.
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evaluation of a mechanical seed planter for transplanting Zostera Marina eelgrass seeds
Aquatic Botany, 2009Co-Authors: Robert J Orth, Scott R Marion, Steven Granger, Michael TraberAbstract:Abstract Few seagrass transplant projects worldwide have relied on seeds, and those projects using Zostera Marina (eelgrass) seeds have generally found low rates of seedling establishment ( −2 into six replicate plots at each of three sites in the Chesapeake Bay region in September 2005, with seedling establishment measured in April 2006. Burying seeds, either with or without gel, had an overall positive effect on seedling establishment, but the effectiveness and the best method varied among sites. Mean seedling establishment for machine-planted seeds was significantly greater than for broadcast seeds at the Piankatank River site (4% vs. 1%), but not at the York (1.2% vs. 1.4%) or Spider Crab Bay (10.1% vs. 7.4%) sites. The effect of the gel was inconsistent among sites, with the highest seedling establishment (18.8%), resulting from seeds injected by pipette without gel at the Spider Crab site. Seed burial shows promise for increasing seedling establishment relative to seed broadcasting in the Chesapeake region, but further investigation of seed–sediment interactions at specific restoration sites is necessary. Low seedling establishment rates remain a bottleneck for seed-based eelgrass restoration.
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innovative techniques for large scale seagrass restoration using Zostera Marina eelgrass seeds
Restoration Ecology, 2008Co-Authors: Scott R Marion, Robert J OrthAbstract:The use of Zostera Marina (eelgrass) seeds for seagrass restoration is increasingly recognized as an alternative to transplanting shoots as losses of seagrass habitat generate interest in large-scale restoration. We explored new techniques for efficient large-scale restoration of Z. Marina using seeds by addressing the factors limiting seed collection, processing, survival, and distribution. We tested an existing mechanical harvesting system for expanding the scale of seed collections, and developed and evaluated two new experimental systems. A seeding technique using buoys holding reproductive shoots at restoration sites to eliminate seed storage was tested along with new techniques for reducing seed-processing labor. A series of experiments evaluated storage conditions that maintain viability of seeds during summer storage for fall planting. Finally, a new mechanical seed-planting technique appropriate for large scales was developed and tested. Mechanical harvesting was an effective approach for collecting seeds, and impacts on donor beds were low. Deploying seed-bearing shoots in buoys produced fewer seedlings and required more effort than isolating, storing, and hand-broadcasting seeds in the fall. We show that viable seeds can be separated from grass wrack based on seed fall velocity and that seed survival during storage can be high (92–95% survival over 3 months). Mechanical seed-planting did not enhance seedling establishment at our sites, but may be a useful tool for evaluating restoration sites. Our work demonstrates the potential for expanding the scale of seed-based Z. Marina restoration but the limiting factor remains the low rate of initial seedling establishment from broadcast seeds.
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operation of the xanthophyll cycle in the seagrass Zostera Marina in response to variable irradiance
Journal of Experimental Marine Biology and Ecology, 2002Co-Authors: Peter J Ralph, Robert J Orth, S M Polk, Kenneth A Moore, Walker O SmithAbstract:Changes in the photobiology and photosynthetic pigments of the seagrass Zostera Marina from Chesapeake Bay (USA) were examined under a range of natural and manipulated irradiance regimes. Photosynthetic activity was assessed using chlorophyll-a fluorescence, and photosynthetic pigments were measured by HPLC. Large changes in the violaxanthin, zeaxanthin, and antheraxanthin content were concomitant with the modulation of non-photochemical quenching (NPQ). Photokinetics (Fv/Fm, rapid light curves (RLC), and non-photochemical quenching) varied as a result of oscillating irradiance and were highly correlated to xanthophyll pigment content. Zeaxanthin and antheraxanthin concentrations increased under elevated light conditions, while violaxanthin increased in darkened conditions. Unusually high concentrations of antheraxanthin were found in Z. Marina under a wide range of light conditions, and this was associated with the partial conversion of violaxanthin to zeaxanthin. These results support the idea that xanthophyll intermediate pigments induce a photoprotective response during exposure to high irradiances in this seagrass.
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relative effects of nutrient enrichment and grazing on epiphyte macrophyte Zostera Marina l dynamics
Oecologia, 1993Co-Authors: Hilary A Neckles, Richard L Wetzel, Robert J OrthAbstract:The independent and interactive effects of nutrient concentration and epiphyte grazers on epiphyte biomass and macrophyte growth and production were examined in Zostera Marina L. (eelgrass) microcosms. Experiments were conducted during early summer, late summer, fall, and spring in a greenhouse on the York River estuary of Chesapeake Bay. Nutrient treatments consisted of ambient or enriched (3× ambient) concentrations of inorganic nitrogen (ammonium nitrate) and phosphate. Grazer treatments consisted of the presence or absence of field densities of isopods, amphipods, and gastropods. epiphyte biomass increased with both grazer removal and nutrient enrichment during summer and spring experiments. The effect of grazers was stronger than that of nutrients. There was little epiphyte response to treatment during the fall, a result possibly of high ambient nutrient concentrations and low grazing pressure. Under low grazer densities of early summer, macrophyte production (g m−2 d−1) was reduced by grazer removal and nutrient enrichment independently. Under high grazer densities of late summer, macrophyte production was reduced by enrichment only with grazers absent. During spring and fall there were no macrophyte responses to treatment. The relative influence of epiphytes on macrophyte production may have been related to seasonally changing water temperature and macrophyte requirements for light and inorganic carbon.
