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Nina Bednarsek - One of the best experts on this subject based on the ideXlab platform.
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Pteropods make thinner shells in the upwelling region of the California Current Ecosystem.
Scientific reports, 2021Co-Authors: Lisette Mekkes, Nina Bednarsek, Richard A Feely, Jef Huisman, Simone R. Alin, Willem Renema, Peter Roessingh, Katja T. C. A. PeijnenburgAbstract:Shelled Pteropods are widely regarded as bioindicators for ocean acidification, because their fragile aragonite shells are susceptible to increasing ocean acidity. While short-term incubations have demonstrated that Pteropod calcification is negatively impacted by ocean acidification, we know little about net calcification in response to varying ocean conditions in natural populations. Here, we examine in situ calcification of Limacina helicina Pteropods collected from the California Current Ecosystem, a coastal upwelling system with strong spatial gradients in ocean carbonate chemistry, dissolved oxygen and temperature. Depth-averaged pH ranged from 8.03 in warmer offshore waters to 7.77 in cold CO2-rich waters nearshore. Based on high-resolution micro-CT technology, we showed that shell thickness declined by ~ 37% along the upwelling gradient from offshore to nearshore water. Dissolution marks covered only ~ 2% of the shell surface area and were not associated with the observed variation in shell thickness. We thus infer that Pteropods make thinner shells where upwelling brings more acidified and colder waters to the surface. Probably the thinner shells do not result from enhanced dissolution, but are due to a decline in calcification. Reduced calcification of Pteropods is likely to have major ecological and biogeochemical implications for the cycling of calcium carbonate in the oceans.
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Eco-physiological responses of copepods and Pteropods to ocean warming and acidification.
Scientific reports, 2019Co-Authors: Jonna Engström-Öst, Richard A Feely, Olivier Glippa, Mirella Kanerva, Julie E. Keister, Simone R. Alin, Brendan R. Carter, Anna K. Mclaskey, Kristiina Vuori, Nina BednarsekAbstract:We compare physiological responses of the crustacean copepod Calanus pacificus and pelagic Pteropod mollusk Limacina helicina to ocean temperatures and pH by measuring biomarkers of oxidative stress, antioxidant defences, and the activity of the respiratory electron transport system in organisms collected on the 2016 West Coast Ocean Acidification cruise in the California Current System. Copepods and Pteropods exhibited strong but divergent responses in the same habitat; copepods had higher oxygen-reactive absorbance capacity, glutathione-S-transferase, and total glutathione content. The ratio between reduced to oxidised glutathione was higher in copepods than in Pteropods, indicating lower oxidative stress in copepods. Pteropods showed higher activities of glutathione reductase, catalase, and lipid peroxidation, indicating increased antioxidant defences and oxidative stress. Thus, the antioxidant defence system of the copepods has a greater capacity to respond to oxidative stress, while Pteropods already face severe stress and show limited capacity to deal with further changes. The results suggest that copepods have higher adaptive potential, owing to their stronger vertical migration behaviour and efficient glutathione metabolism, whereas Pteropods run the risk of oxidative stress and mortality under high CO2 conditions. Our results provide a unique dataset and evidence of stress-inducing mechanisms behind Pteropod ocean acidification responses.
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exposure history determines Pteropod vulnerability to ocean acidification along the us west coast
Scientific Reports, 2017Co-Authors: Nina Bednarsek, Richard A Feely, Nick Tolimieri, Albert J Hermann, Samantha A Siedlecki, George G Waldbusser, Paul Mcelhany, Simone R. AlinAbstract:The Pteropod Limacina helicina frequently experiences seasonal exposure to corrosive conditions (Ωar < 1) along the US West Coast and is recognized as one of the species most susceptible to ocean acidification (OA). Yet, little is known about their capacity to acclimatize to such conditions. We collected Pteropods in the California Current Ecosystem (CCE) that differed in the severity of exposure to Ωar conditions in the natural environment. Combining field observations, high-CO2 perturbation experiment results, and retrospective ocean transport simulations, we investigated biological responses based on histories of magnitude and duration of exposure to Ωar < 1. Our results suggest that both exposure magnitude and duration affect Pteropod responses in the natural environment. However, observed declines in calcification performance and survival probability under high CO2 experimental conditions do not show acclimatization capacity or physiological tolerance related to history of exposure to corrosive conditions. Pteropods from the coastal CCE appear to be at or near the limit of their physiological capacity, and consequently, are already at extinction risk under projected acceleration of OA over the next 30 years. Our results demonstrate that Ωar exposure history largely determines Pteropod response to experimental conditions and is essential to the interpretation of biological observations and experimental results.
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new ocean new needs application of Pteropod shell dissolution as a biological indicator for marine resource management
Ecological Indicators, 2017Co-Authors: Nina Bednarsek, Chris J Harvey, Richard A Feely, Terrie Klinger, Stephen B Weisberg, R M Mccabe, Jan Newton, Nick TolimieriAbstract:Abstarct Pteropods, planktonic marine snails with a cosmopolitan distribution, are highly sensitive to changing ocean chemistry. Graphical abstract shows Pteropod responses to be related to aragonite saturation state, with progressing decrease in Ω ar causing deteriorating biological conditions. Under high saturation state (Ω ar > 1.1; zone 0), Pteropods are healthy with no presence of stress or shell dissolution. With decreasing Ω ar (zone 1), Pteropod stress is demonstrated through increased dissolution and reduced calcification. At Ω ar
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Pteropods on the edge cumulative effects of ocean acidification warming and deoxygenation
Progress in Oceanography, 2016Co-Authors: Nina Bednarsek, Chris J Harvey, Isaac C Kaplan, Richard A Feely, Jasna MožinaAbstract:Abstract We review the state of knowledge of the individual and community responses of euthecosome (shelled) Pteropods in the context of global environmental change. In particular, we focus on their responses to ocean acidification, in combination with ocean warming and ocean deoxygenation, as inferred from a growing body of empirical literature, and their relatively nascent place in ecosystem-scale models. Our objectives are: (1) to summarize the threats that these stressors pose to Pteropod populations; (2) to demonstrate that Pteropods are strong candidate indicators for cumulative effects of OA, warming, and deoxygenation in marine ecosystems; and (3) to provide insight on incorporating Pteropods into population and ecosystem models, which will help inform ecosystem-based management of marine resources under future environmental regimes.
Amy E. Maas - One of the best experts on this subject based on the ideXlab platform.
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The origin and diversification of Pteropods precede past perturbations in the Earth's carbon cycle
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Katja T. C. A. Peijnenburg, Arie W. Janssen, Deborah Wall-palmer, Erica Goetze, Amy E. Maas, Jonathan A. Todd, Ferdinand MarlétazAbstract:Pteropods are a group of planktonic gastropods that are widely regarded as biological indicators for assessing the impacts of ocean acidification. Their aragonitic shells are highly sensitive to acute changes in ocean chemistry. However, to gain insight into their potential to adapt to current climate change, we need to accurately reconstruct their evolutionary history and assess their responses to past changes in the Earth's carbon cycle. Here, we resolve the phylogeny and timing of Pteropod evolution with a phylogenomic dataset (2,654 genes) incorporating new data for 21 Pteropod species and revised fossil evidence. In agreement with traditional taxonomy, we recovered molecular support for a division between "sea butterflies" (Thecosomata; mucus-web feeders) and "sea angels" (Gymnosomata; active predators). Molecular dating demonstrated that these two lineages diverged in the early Cretaceous, and that all main Pteropod clades, including shelled, partially-shelled, and unshelled groups, diverged in the mid- to late Cretaceous. Hence, these clades originated prior to and subsequently survived major global change events, including the Paleocene-Eocene Thermal Maximum (PETM), the closest analog to modern-day ocean acidification and warming. Our findings indicate that planktonic aragonitic calcifiers have shown resilience to perturbations in the Earth's carbon cycle over evolutionary timescales.
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Effects of temperature and food concentration on Pteropod metabolism along the Western Antarctic Peninsula
Journal of Experimental Marine Biology and Ecology, 2020Co-Authors: Patricia S. Thibodeau, Deborah K. Steinberg, Amy E. MaasAbstract:Abstract Pteropods (pelagic snails) are abundant zooplankton in the Southern Ocean where they are important grazers of phytoplankton, prey for higher trophic levels, and sensitive to environmental change. The Western Antarctic Peninsula (WAP) is a highly dynamic and productive region that has undergone rapid warming, but little is known about how environmental changes there will affect Pteropod physiology. In this study, the effects of warming seawater temperatures and shifting food availability on Limacina helicina antarctica metabolism (respiration and excretion) were determined by conducting shipboard experiments that exposed Pteropods to a range of temperatures and phytoplankton (food) concentrations. Highest respiration (up to 69 μmol O2 gDW−1 h−1) and usually highest excretion rates occurred under higher temperature with more limited metabolic response to food concentration, indicating these factors do not always have an additive effect on Pteropod metabolism. The proportion of dissolved organic matter (DOM) to total organic and inorganic dissolved constituents was high and was also significantly affected by shifts in temperature and food. Dissolved organic carbon, nitrogen, and phosphorus (DOC, DON, and DOP) were on average 27, 51, and 11.5% of the total C, N, and P metabolized, respectively. The proportion of total N excreted as DON and the proportion of total P excreted as DOP were significantly affected by a combination of shifting temperature and food concentrations. There were no effects of temperature or food on DOC excretion (mean 8.79 μmol C gDW−1 h−1; range 0.44 to 44) as a proportion of total C metabolized. Metabolic O2:N ratio ranged from 2 to 9 and decreased significantly with increasing temperature and food, indicating a shift toward increased protein catabolism. Metabolic ratios of C, N, and P were all below the canonical Redfield ratio, which has implications for phytoplankton nutrient uptake and bacterial production. Respiration rates at ambient conditions of other WAP Pteropods, and excretion rates for Clio pyramidata, were also measured, with respiration rates ranging from 24.39 (Spongiobranchaea australis) to 28.86 (L. h. antarctica) μmol O2 gDW−1 h−1. Finally, a CO2 perturbation experiment measuring L. h. antarctica metabolism under pre-industrial and elevated dissolved pCO2 conditions showed no significant change in mean L. h. antarctica respiration or excretion rates with higher pCO2. These insights into the metabolic response of Pteropods to ocean variability increase our understanding of the role of zooplankton in biogeochemical cycles and help predict future responses to climate change.
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The origin and diversification of Pteropods predate past perturbations in the Earth’s carbon cycle
2019Co-Authors: Katja T. C. A. Peijnenburg, Arie W. Janssen, Deborah Wall-palmer, Erica Goetze, Amy E. Maas, Jonathan A. Todd, Ferdinand MarlétazAbstract:Summary Pteropods are a group of planktonic gastropods that are widely regarded as biological indicators for assessing the impacts of ocean acidification (OA). Their thin aragonitic shells are highly sensitive to acute changes in ocean chemistry. However, to gain insight into their potential to adapt to current climate change, we need to accurately reconstruct their evolutionary history and assess their responses to past changes in Earth’s carbon cycle. Here, we resolve the phylogeny and timing of Pteropod evolution with a phylogenomic dataset incorporating 21 new species and new fossil evidence. In agreement with traditional taxonomy, we recovered the first molecular support for a division between sea butterflies (Thecosomata: mucus-web feeders) and sea angels (Gymnosomata: active predators). Molecular dating demonstrated that these two lineages diverged in the early Cretaceous, and that all main Pteropod clades, including shelled, partially-shelled and unshelled groups, diverged in the mid to late Cretaceous. Hence, these clades originated prior to and subsequently survived major global change events, including the Paleocene Eocene Thermal Maximum (PETM), which is the closest analogue to modern-day ocean acidification and warming. Our findings indicate that aragonitic calcifiers have been resilient to extreme perturbations in the Earth’s carbon cycle over evolutionary timescales.
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Assembly of a reference transcriptome for the gymnosome Pteropod Clione limacina and profiling responses to short-term CO2 exposure.
Marine genomics, 2017Co-Authors: Ali A. Thabet, Amy E. Maas, Samy A. Saber, Ann M. TarrantAbstract:Abstract The gymnosome (unshelled) Pteropod Clione limacina is a pelagic predatory mollusc found in polar and sub-polar regions. It has been studied for its distinctive swimming behavior and as an obligate predator on the closely related thecosome (shelled) Pteropods. As concern about ocean acidification increases, it becomes useful to compare the physiological responses of closely-related calcifying and non-calcifying species to acidification. The goals of this study were thus to generate a reference transcriptome for Clione limacina, to expose individuals to CO2 for a period of 3 days, and to explore differential patterns of gene expression. Our Trinity assembly contained 300,994 transcripts of which ~ 26% could be annotated. In total, only 41 transcripts were differentially expressed following the CO2 treatment, consistent with a limited physiological response of this species to short-term CO2 exposure. The differentially expressed genes identified in our study were largely distinct from those identified in previous studies of thecosome Pteropods, although some similar transcripts were identified, suggesting that comparison of these transcriptomes and responses may provide insight into differences in responses to ocean acidification among phylogenetically and functionally distinct molluscan lineages.
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The effect of elevated carbon dioxide on the sinking and swimming of the shelled Pteropod Limacina retroversa
ICES Journal of Marine Science, 2017Co-Authors: Alexander J. Bergan, Amy E. Maas, Gareth L. Lawson, Zhaohui Aleck WangAbstract:Abstract Shelled Pteropods are planktonic molluscs that may be affected by ocean acidification. Limacina retroversa from the Gulf of Maine were used to investigate the impact of elevated carbon dioxide (CO2) on shell condition as well as swimming and sinking behaviours. Limacina retroversa were maintained at either ambient (ca. 400 µatm) or two levels of elevated CO2 (800 and 1200 µatm) for up to 4 weeks, and then examined for changes in shell transparency, sinking speed, and swimming behaviour assessed through a variety of metrics (e.g. speed, path tortuosity, and wing beat frequency). After exposures to elevated CO2 for as little as 4 d, the Pteropod shells were significantly darker and more opaque in the elevated CO2 treatments. Sinking speeds were significantly slower for Pteropods exposed to medium and high CO2 in comparison to the ambient treatment. Swimming behaviour showed less clear patterns of response to treatment and duration of exposure, but overall, swimming did not appear to be hindered under elevated CO2. Sinking is used by L. retroversa for predator evasion, and altered speeds and increased visibility could increase the susceptibility of Pteropods to predation.
M. V. S. Guptha - One of the best experts on this subject based on the ideXlab platform.
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Timing and preservation mechanism of deglacial Pteropod spike from the Andaman Sea, northeastern Indian Ocean
Boreas, 2014Co-Authors: A. V. Sijinkumar, M. V. S. Guptha, B.n. Nath, Syed Masood Ahmad, Bandaru R. RaoAbstract:The aragonite compensation depth (ACD) fluctuated considerably during the last glacial until the Holocene with a dominant Pteropod preservation spike during the deglacial period, which is prominently seen in three well-dated cores covering the Andaman Sea, northeastern Indian Ocean. The precise time period of the preservation spike of Pteropods is not known but this knowledge is crucial for stratigraphical correlation and also for understanding the driving mechanism. Isotopic and foraminiferal proxies were used to decipher the possible mechanism for Pteropods preservation in the Andaman Sea. The poor preservation/absence of Pteropods during the Holocene in the Andaman Sea may have implications for ocean acidification, driven by enhanced atmospheric CO2 concentration. Strengthening of the summer monsoon and the resultant high biological productivity may also have played a role in the poor preservation of Pteropods. The deglacial Pteropod spike is characterized by high abundance/preservation of the Pteropods between ∼19 and 15 cal. ka BP, associated with very low atmospheric CO2 concentration. Isotope data suggest the prevalence of a glacial environment with reduced sea surface temperature, upwelling and enhanced salinity during the Pteropod preservation spike. Total planktic foraminifera and Globigerina bulloides abundances are low during this period, implying a weakened summer monsoon and reduced foraminiferal productivity. Based on the preservation record of Pteropods, it is inferred that the ACD was probably deepest (>2900 m) at 16.5 cal. ka BP. The synchronous regional occurrence of the Pteropod preservation spike in the Andaman Sea and in the northwestern Indian Ocean could potentially be employed as a stratigraphic marker.
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Late Quaternary record of Pteropod preservation from the Andaman Sea
Marine Geology, 2010Co-Authors: A. V. Sijinkumar, B. Nagender Nath, M. V. S. GupthaAbstract:Abstract In order to understand the glacial to interglacial fluctuations in Pteropod preservation and productivity during the late Quaternary (∼ 54 ka BP to present), we investigated Pteropod, organic carbon (Corg) and Globigerina bulloides abundance in a deep sea core from the western Andaman Sea. Pteropod abundance and preservation is similar to the “Indo-Pacific carbonate preservation type”, showing better preservation during glacial and poor preservation during interglacial periods. The core site appears to have remained below the aragonite compensation depth (ACD) throughout the Holocene, indicated by the total absence of Pteropods. Maximum abundance and good preservation of Pteropods was observed during stadials such as Younger Dryas (YD), Heinrich Events (HEs) and Last Glacial Maxima (LGM) indicating weaker oxygen minimum zone (OMZ) and deeper ACD. Furthermore, the high relative abundance of mesopelagic Pteropods over epipelagic forms suggests a well ventilated water column with weak OMZ particularly during LGM, apparently driven by intense winter monsoon. Increased monsoon-driven productivity was observed during 45–40 ka, of early Marine Isotope Stage 2 (MIS 2, 24–22 ka), Bolling/Allerod (B/A; 15–13.5 ka), YD and late Holocene as evidenced by Corg content and G. bulloides. Enhanced Pteropod preservation of H1 associated with low Corg content and G. bulloides suggests that reduced monsoonal driven productivity might have influenced Pteropod preservation. Deglacial preservation spike in the Andaman Sea is consistent with other northern Indian Ocean records and elsewhere outside the Indian Ocean implying the event is global in nature, marked by deepening of ACD probably driven by enhancement of winter monsoon on local and changes in intermediate water circulation on regional scale.
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Seasonal variation of Pteropods from the Western Arabian Sea sediment trap
Geo-Marine Letters, 2006Co-Authors: R. Mohan, D. K. Sinha, K. Verma, L. P. Mergulhao, S. Shanvas, M. V. S. GupthaAbstract:Sediment trap samples collected from the Western Arabian Sea yielded a rich assemblage of intact and non-living (opaque white) Pteropod tests from a water depth of 919 m during January to September 1993. Nine species of Pteropods were recorded, all (except one) displaying distinct seasonality in abundance, suggesting their response to changing hydrographical conditions influenced by the summer/winter monsoon cycle. Pteropod fluxes increased during the April–May peak of the intermonsoon, and reached maximum levels in the late phase of the southwest summer monsoon, probably due to the shallowing of the mixed layer depth. This shallowing, coupled with enhanced nutrient availability, provides ideal conditions for Pteropod growth, also reflected in corresponding fluctuations in the flux of the foraminifer Globigerina bulloides . Pteropod/planktic foraminifer ratios displayed marked seasonal variations, the values increasing during the warmer months of April and May when planktic foraminiferal fluxes declined. The variation in fluxes of calcium carbonate, organic carbon and biogenic opal show positive correlations with fluxes of Pteropods and planktic foraminifers. Calcium carbonate was the main contributor to the total particulate flux, especially during the SW monsoon. In the study area, Pteropod flux variations are similar to the other flux patterns, indicating that they, too could be used as a potential tool for palaeoclimatic reconstruction of the recent past.
Deborah Wall-palmer - One of the best experts on this subject based on the ideXlab platform.
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The origin and diversification of Pteropods precede past perturbations in the Earth's carbon cycle
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Katja T. C. A. Peijnenburg, Arie W. Janssen, Deborah Wall-palmer, Erica Goetze, Amy E. Maas, Jonathan A. Todd, Ferdinand MarlétazAbstract:Pteropods are a group of planktonic gastropods that are widely regarded as biological indicators for assessing the impacts of ocean acidification. Their aragonitic shells are highly sensitive to acute changes in ocean chemistry. However, to gain insight into their potential to adapt to current climate change, we need to accurately reconstruct their evolutionary history and assess their responses to past changes in the Earth's carbon cycle. Here, we resolve the phylogeny and timing of Pteropod evolution with a phylogenomic dataset (2,654 genes) incorporating new data for 21 Pteropod species and revised fossil evidence. In agreement with traditional taxonomy, we recovered molecular support for a division between "sea butterflies" (Thecosomata; mucus-web feeders) and "sea angels" (Gymnosomata; active predators). Molecular dating demonstrated that these two lineages diverged in the early Cretaceous, and that all main Pteropod clades, including shelled, partially-shelled, and unshelled groups, diverged in the mid- to late Cretaceous. Hence, these clades originated prior to and subsequently survived major global change events, including the Paleocene-Eocene Thermal Maximum (PETM), the closest analog to modern-day ocean acidification and warming. Our findings indicate that planktonic aragonitic calcifiers have shown resilience to perturbations in the Earth's carbon cycle over evolutionary timescales.
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The origin and diversification of Pteropods predate past perturbations in the Earth’s carbon cycle
2019Co-Authors: Katja T. C. A. Peijnenburg, Arie W. Janssen, Deborah Wall-palmer, Erica Goetze, Amy E. Maas, Jonathan A. Todd, Ferdinand MarlétazAbstract:Summary Pteropods are a group of planktonic gastropods that are widely regarded as biological indicators for assessing the impacts of ocean acidification (OA). Their thin aragonitic shells are highly sensitive to acute changes in ocean chemistry. However, to gain insight into their potential to adapt to current climate change, we need to accurately reconstruct their evolutionary history and assess their responses to past changes in Earth’s carbon cycle. Here, we resolve the phylogeny and timing of Pteropod evolution with a phylogenomic dataset incorporating 21 new species and new fossil evidence. In agreement with traditional taxonomy, we recovered the first molecular support for a division between sea butterflies (Thecosomata: mucus-web feeders) and sea angels (Gymnosomata: active predators). Molecular dating demonstrated that these two lineages diverged in the early Cretaceous, and that all main Pteropod clades, including shelled, partially-shelled and unshelled groups, diverged in the mid to late Cretaceous. Hence, these clades originated prior to and subsequently survived major global change events, including the Paleocene Eocene Thermal Maximum (PETM), which is the closest analogue to modern-day ocean acidification and warming. Our findings indicate that aragonitic calcifiers have been resilient to extreme perturbations in the Earth’s carbon cycle over evolutionary timescales.
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Diversity and abundance of Pteropods and heteropods along a latitudinal gradient across the Atlantic Ocean
Progress in Oceanography, 2017Co-Authors: Alice K. Burridge, Deborah Wall-palmer, Erica Goetze, Serena L. Le Double, Jef Huisman, Katja T. C. A. PeijnenburgAbstract:Shelled Pteropods and heteropods are two independent groups of holoplanktonic gastropods that are potentially good indicators of the effects of ocean acidification. Although insight into their ecology and biogeography is important for predicting species-specific sensitivities to ocean change, the species abundances and biogeographical distributions of Pteropods and heteropods are still poorly known. Here, we examined abundance and distribution patterns of Pteropods (euthecosomes, pseudothecosomes, gymnosomes) and heteropods at 31 stations along a transect from 46°N to 46°S across the open waters of the Atlantic Ocean (Atlantic Meridional Transect cruise AMT24). We collected a total of 7312 Pteropod specimens belonging to at least 31 species. Pteropod abundances were low north of 40°N with 4000 ind./1000 m3 just south of 40°S. This accounted for an estimated biomass of 3.2 mg m−3 south of 40°S and an average of 0.49 mg m−3 along the entire transect. Species richness of Pteropods was highest in the stratified (sub)tropical waters between 30°N and 30°S, with a maximum of 15 species per station. The biogeographical distribution of Pteropod assemblages inferred by cluster analysis was largely congruent with the distribution of Longhurst’s biogeochemical provinces. Some Pteropod species distributions were limited to particular oceanographic provinces, for example, subtropical gyres (e.g. Styliola subula) or warm equatorial waters (e.g. Creseis virgula). Other species showed much broader distributions between ∼35°N and ∼35°S (e.g. Limacina bulimoides and Heliconoides inflatus). We collected 1812 heteropod specimens belonging to 18 species. Highest heteropod abundances and species richness were found between 30°N and 20°S, with up to ∼700 ind./1000 m3 and a maximum of 14 species per station. Heteropods were not restricted to tropical and subtropical waters, however, as some taxa were also relatively abundant in subantarctic waters. Given the variation in distribution patterns among Pteropod and heteropod species, it is likely that species will differ in their response to ocean changes.
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Pteropods from the Caribbean Sea: variations in calcification as an indicator of past ocean carbonate saturation
Biogeosciences, 2016Co-Authors: Deborah Wall-palmer, Malcolm B. Hart, R. S. J. Sparks, Anne Le Friant, G. Boudon, Christine Deplus, C. Smart, Jean-christophe KomorowskiAbstract:The aragonite shell-bearing thecosome Pteropods are an important component of the oceanic plankton. However , with increasing pCO 2 and the associated reduction in oceanic pH (ocean acidification), thecosome Pteropods are thought to be particularly vulnerable to shell dissolution. The distribution and preservation of Pteropods over the last 250 000 years have been investigated in marine sediment cores from the Caribbean Sea close to the island of Montserrat. Using the Limacina Dissolution Index (LDX), fluctuations in Pteropod calcification through the most recent glacial/interglacial cycles are documented. By comparison to the oxygen isotope record (global ice volume), we show that Pteropod calcification is closely linked to global changes in pCO 2 and pH and is, therefore, a global signal. These data are in agreement with the findings of experiments upon living Pteropods, which show that variations in pH can greatly affect aragonitic shells. The results of this study provide information which may be useful in the prediction of future changes to the Pteropod assemblage caused by ocean acidification.
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In-life Pteropod shell dissolution as an indicator of past ocean carbonate saturation
Quaternary Science Reviews, 2013Co-Authors: Deborah Wall-palmer, Christopher W. Smart, Malcolm B. HartAbstract:Abstract Recent concern over the effects of ocean acidification upon calcifying organisms has highlighted the aragonitic shelled thecosomatous Pteropods as being at a high risk. Both in-situ and laboratory studies have shown that an increased dissolved CO 2 concentration, leading to decreased water pH and low carbonate concentration, causes reduced calcification rates and enhanced dissolution in the shells of living Pteropods. In fossil records unaffected by post-depositional dissolution, this in-life shell dissolution can be detected. Here we present the first evidence of variations of in-life Pteropod shell dissolution due to variations in surface water carbonate concentration during the Late Pleistocene by analysing the surface layer of Pteropod shells in marine sediment cores from the Caribbean Sea and Indian Ocean. In-life shell dissolution was determined by applying the Limacina Dissolution Index (LDX) to the sub-tropical Pteropod Limacina inflata . Average shell size information shows that high in-life dissolution is accompanied by smaller shell sizes in L. inflata , which may indicate a reduction in calcification rate. Comparison of the LDX profile to Late Pleistocene Vostok atmospheric CO 2 concentrations, shows that in-life Pteropod dissolution is closely associated to variations in past ocean carbonate saturation. This study confirms the findings of laboratory studies, showing enhanced shell dissolution and reduced calcification in living Pteropods when surface ocean carbonate concentrations were lower. Results also demonstrate that oceanic pH levels that were less acidic and changing less rapidly than those predicted for the 21st Century, negatively affected Pteropods during the Late Pleistocene.
Richard A Feely - One of the best experts on this subject based on the ideXlab platform.
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Pteropods make thinner shells in the upwelling region of the California Current Ecosystem.
Scientific reports, 2021Co-Authors: Lisette Mekkes, Nina Bednarsek, Richard A Feely, Jef Huisman, Simone R. Alin, Willem Renema, Peter Roessingh, Katja T. C. A. PeijnenburgAbstract:Shelled Pteropods are widely regarded as bioindicators for ocean acidification, because their fragile aragonite shells are susceptible to increasing ocean acidity. While short-term incubations have demonstrated that Pteropod calcification is negatively impacted by ocean acidification, we know little about net calcification in response to varying ocean conditions in natural populations. Here, we examine in situ calcification of Limacina helicina Pteropods collected from the California Current Ecosystem, a coastal upwelling system with strong spatial gradients in ocean carbonate chemistry, dissolved oxygen and temperature. Depth-averaged pH ranged from 8.03 in warmer offshore waters to 7.77 in cold CO2-rich waters nearshore. Based on high-resolution micro-CT technology, we showed that shell thickness declined by ~ 37% along the upwelling gradient from offshore to nearshore water. Dissolution marks covered only ~ 2% of the shell surface area and were not associated with the observed variation in shell thickness. We thus infer that Pteropods make thinner shells where upwelling brings more acidified and colder waters to the surface. Probably the thinner shells do not result from enhanced dissolution, but are due to a decline in calcification. Reduced calcification of Pteropods is likely to have major ecological and biogeochemical implications for the cycling of calcium carbonate in the oceans.
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Eco-physiological responses of copepods and Pteropods to ocean warming and acidification.
Scientific reports, 2019Co-Authors: Jonna Engström-Öst, Richard A Feely, Olivier Glippa, Mirella Kanerva, Julie E. Keister, Simone R. Alin, Brendan R. Carter, Anna K. Mclaskey, Kristiina Vuori, Nina BednarsekAbstract:We compare physiological responses of the crustacean copepod Calanus pacificus and pelagic Pteropod mollusk Limacina helicina to ocean temperatures and pH by measuring biomarkers of oxidative stress, antioxidant defences, and the activity of the respiratory electron transport system in organisms collected on the 2016 West Coast Ocean Acidification cruise in the California Current System. Copepods and Pteropods exhibited strong but divergent responses in the same habitat; copepods had higher oxygen-reactive absorbance capacity, glutathione-S-transferase, and total glutathione content. The ratio between reduced to oxidised glutathione was higher in copepods than in Pteropods, indicating lower oxidative stress in copepods. Pteropods showed higher activities of glutathione reductase, catalase, and lipid peroxidation, indicating increased antioxidant defences and oxidative stress. Thus, the antioxidant defence system of the copepods has a greater capacity to respond to oxidative stress, while Pteropods already face severe stress and show limited capacity to deal with further changes. The results suggest that copepods have higher adaptive potential, owing to their stronger vertical migration behaviour and efficient glutathione metabolism, whereas Pteropods run the risk of oxidative stress and mortality under high CO2 conditions. Our results provide a unique dataset and evidence of stress-inducing mechanisms behind Pteropod ocean acidification responses.
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exposure history determines Pteropod vulnerability to ocean acidification along the us west coast
Scientific Reports, 2017Co-Authors: Nina Bednarsek, Richard A Feely, Nick Tolimieri, Albert J Hermann, Samantha A Siedlecki, George G Waldbusser, Paul Mcelhany, Simone R. AlinAbstract:The Pteropod Limacina helicina frequently experiences seasonal exposure to corrosive conditions (Ωar < 1) along the US West Coast and is recognized as one of the species most susceptible to ocean acidification (OA). Yet, little is known about their capacity to acclimatize to such conditions. We collected Pteropods in the California Current Ecosystem (CCE) that differed in the severity of exposure to Ωar conditions in the natural environment. Combining field observations, high-CO2 perturbation experiment results, and retrospective ocean transport simulations, we investigated biological responses based on histories of magnitude and duration of exposure to Ωar < 1. Our results suggest that both exposure magnitude and duration affect Pteropod responses in the natural environment. However, observed declines in calcification performance and survival probability under high CO2 experimental conditions do not show acclimatization capacity or physiological tolerance related to history of exposure to corrosive conditions. Pteropods from the coastal CCE appear to be at or near the limit of their physiological capacity, and consequently, are already at extinction risk under projected acceleration of OA over the next 30 years. Our results demonstrate that Ωar exposure history largely determines Pteropod response to experimental conditions and is essential to the interpretation of biological observations and experimental results.
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new ocean new needs application of Pteropod shell dissolution as a biological indicator for marine resource management
Ecological Indicators, 2017Co-Authors: Nina Bednarsek, Chris J Harvey, Richard A Feely, Terrie Klinger, Stephen B Weisberg, R M Mccabe, Jan Newton, Nick TolimieriAbstract:Abstarct Pteropods, planktonic marine snails with a cosmopolitan distribution, are highly sensitive to changing ocean chemistry. Graphical abstract shows Pteropod responses to be related to aragonite saturation state, with progressing decrease in Ω ar causing deteriorating biological conditions. Under high saturation state (Ω ar > 1.1; zone 0), Pteropods are healthy with no presence of stress or shell dissolution. With decreasing Ω ar (zone 1), Pteropod stress is demonstrated through increased dissolution and reduced calcification. At Ω ar
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Pteropods on the edge cumulative effects of ocean acidification warming and deoxygenation
Progress in Oceanography, 2016Co-Authors: Nina Bednarsek, Chris J Harvey, Isaac C Kaplan, Richard A Feely, Jasna MožinaAbstract:Abstract We review the state of knowledge of the individual and community responses of euthecosome (shelled) Pteropods in the context of global environmental change. In particular, we focus on their responses to ocean acidification, in combination with ocean warming and ocean deoxygenation, as inferred from a growing body of empirical literature, and their relatively nascent place in ecosystem-scale models. Our objectives are: (1) to summarize the threats that these stressors pose to Pteropod populations; (2) to demonstrate that Pteropods are strong candidate indicators for cumulative effects of OA, warming, and deoxygenation in marine ecosystems; and (3) to provide insight on incorporating Pteropods into population and ecosystem models, which will help inform ecosystem-based management of marine resources under future environmental regimes.