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  • 11
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    Seasonal variability of stable carbon isotopes (〈delta〉13CDIC) in the Skagerrak and the Baltic Sea: Distinguishing between mixing and biological productivity (2017)
    ELSEVIER SCIENCE BV
    In:  EPIC3Palaeogeography Palaeoclimatology Palaeoecology, ELSEVIER SCIENCE BV, 483, pp. 15-30, ISSN: 0031-0182
    Details
    Publication Date: 2017-09-01
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 12
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    COMBINED IMPACTS OF OCEAN ACIDIFICATION AND DYSOXIA ON SURVIVAL AND GROWTH OF FOUR AGGLUTINATING FORAMINIFERA (2017)
    CUSHMAN FOUNDATION FORAMINIFERAL RES
    In:  EPIC3Journal of Foraminiferal Research, CUSHMAN FOUNDATION FORAMINIFERAL RES, 47(3), pp. 294-303, ISSN: 0096-1191
    Details
    Publication Date: 2017-07-12
    Description: Agglutinated foraminifera create a shell by assembling particles from the sediment and comprise a significant part of the foraminiferal fauna. Despite their high abundance and diversity, their response to environmental perturbations and climate change is relatively poorly studied. Here we present results from a culture experiment with four different species of agglutinating foraminifera incubated in artificial substrate and exposed to different pCO2 conditions, in either dysoxic or oxic settings. We observed species-specific reactions (i.e., reduced or increased chamber formation rates) to dysoxia and/or acidification. While chamber addition and/or survival rates of Miliammina fusca and Trochammina inflata were negatively impacted by either dysoxia or acidification, respectively, Textularia tenuissima and Spiroplectammina biformis had the highest survivorship and chamber addition rates with combined high pCO2 (2000 ppm) and low O2 (0.7 ml/l) conditions. The differential response of these species indicates that not all agglutinating foraminifera are well-adapted to conditions induced by predicted climate change, which may result in a shift in foraminiferal community composition.
    Repository Name: EPIC Alfred Wegener Institut
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  • 13
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    Anaerobic diagenesis of silica and carbon in continental margin sediments : discrete zones of TCO2 production (2005)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 69 (2005): 4611-4629, doi:10.1016/j.gca.2005.05.011.
    Description: Pore water profiles of dissolved Si, Ca2+, SO42-, CH4, and TCO2 (Dissolved Inorganic Carbon; DIC) were determined from multicores and gravity cores collected at nine sites off Southern California, the west coast of Mexico, and within the Gulf of California. These sites were located within the eastern North Pacific oxygen minimum zone at depths of 400 to 900 m and in settings where bottom water oxygen concentrations were 〈3 μM and sediments were laminated. Pore water profiles were defined at a resolution of millimeters (whole core squeezing), centimeters (sectioning and squeezing) and meters (gravity core sectioning and squeezing), and diffusive fluxes were calculated for different zones within the sediment column. The flux of dissolved silica across the sediment-water interface (SWI) ranged from 0.3 to 3.4 mmol Si m-2d-1, and TCO2 fluxes ranged from 0.8 to 4.6 mmol C m-2d-1. A positive correlation (r = 0.74) existed between these fluxes, yet these two constituents exhibited significantly different diagenetic behavior downcore; dissolved Si generally reached a constant concentration (between 450 and 900 μM) in the upper few cm, whereas TCO2 concentrations increased monotonically with depth. Methane was detected at micromolar levels in sediment intervals between 0 and 60 cm and at five sites, increased to millimolar levels at depths of 80 to 170 cm. At the horizon marking the appearance of millimolar levels of methane, there was a distinct change in slope of the sulfate and TCO2 gradients. A flux budget for this horizon was determined by using linear fits to pore water profiles; these budgets indicate that the upward TCO2 flux away from this horizon is 40 to 50% greater than the downward sulfate flux to this horizon. Given that the TCO2 flux to this horizon from below was quite small, this imbalance suggests that anaerobic oxidation of methane by sulfate is not the only process producing TCO2 within this horizon. A budget for TCO2 at this horizon is balanced when 40 to 80% of the sulfate flux is attributed to organic carbon remineralization. Of the DIC that diffuses across the SWI, 20 to 40% is generated by reactions occurring within or below this deep reaction horizon.
    Description: Funding for the work was provided by NSF-OCE-0002250 to L. Stott, W. Berelson and R. Douglas, NSF-OCE-0129555 to W. Berelson, and NSF-OCE-9911649 to F. Sansone.
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 14
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    Tolerance of allogromiid Foraminifera to severely elevated carbon dioxide concentrations : implications to future ecosystem functioning and paleoceanographic interpretations (2009)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Global and Planetary Change 65 (2009): 107-114, doi:10.1016/j.gloplacha.2008.10.013.
    Description: Increases in the partial pressure of carbon dioxide (pCO2) in the atmosphere will significantly affect a wide variety of terrestrial fauna and flora. Because of tight atmospheric-oceanic coupling, shallow-water marine species are also expected to be affected by increases in atmospheric carbon dioxide concentrations. One proposed way to slow increases in atmospheric pCO2 is to sequester CO2 in the deep sea. Thus, over the next few centuries marine species will be exposed to changing seawater chemistry caused by ocean-atmospheric exchange and/or deep-ocean sequestration. This initial case study on one allogromiid foraminiferal species (Allogromia laticollaris) was conducted to begin to ascertain the effect of elevated pCO2 on benthic Foraminifera, which are a major meiofaunal constituent of shallow- and deep-water marine communities. Cultures of this thecate foraminiferan protist were used for 10-14-day experiments. Experimental treatments were executed in an incubator that controlled CO2 (15 000; 30 000; 60 000; 90 000; 200 000 ppm), temperature and humidity; atmospheric controls (i.e., ~375 ppm CO2) were executed simultaneously. Although the experimental elevated pCO2 values are far above foreseeable surface water pCO2, they were selected to represent the spectrum of conditions expected for the benthos if deep-sea CO2 sequestration becomes a reality. Survival was assessed in two independent ways: pseudopodial presence/absence and measurement of adenosine triphosphate (ATP), which is an indicator of cellular energy. Substantial proportions of A. laticollaris populations survived 200 000 ppm CO2 although the mean of the median [ATP] of survivors was statistically lower for this treatment than for that of atmospheric control specimens. After individuals that had been incubated in 200 000 ppm CO2 for 12 days were transferred to atmospheric conditions for ~24 hours, the [ATP] of live specimens (survivors) approximated those of the comparable atmospheric control treatment. Incubation in 200 000 ppm CO2 also resulted in reproduction by some individuals. Results suggest that certain Foraminifera are able to tolerate deep-sea CO2 sequestration and perhaps thrive as a result of elevated pCO2 that is predicted for the next few centuries, in a high-pCO2 world. Thus, allogromiid foraminiferal “blooms” may result from climate change. Furthermore, because allogromiids consume a variety of prey, it is likely that they will be major players in ecosystem dynamics of future coastal sedimentary environments.
    Description: This work was funded by US Department of Energy grant # DE-FG02-03ER63696 (to J. Kennett and J. Bernhard), NSF OCE-0725966, and the WHOI Summer Student Fellow Program, which is funded by NSF Research Experience for Undergraduates Program grant #OCE-0139423.
    Keywords: Allogromia laticollaris ; CO2 injection ; Deep-sea ; Climate change ; Hypercapnia
    Repository Name: Woods Hole Open Access Server
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  • 15
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    Benthic foraminifera living in Gulf of Mexico bathyal and abyssal sediments : community analysis and comparison to metazoan meiofaunal biomass and density (2009)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 55 (2008): 2617-2626, doi:10.1016/j.dsr2.2008.07.011.
    Description: Benthic foraminiferal biomass, density, and species composition were determined at ten sites in the Gulf of Mexico. During June 2001 and June 2002, sediment samples were collected with a GoMex boxcorer. A 7.5-cm diameter subcore was taken from a box core collected at each site and sliced into 1-cm or 2-cm sections to a depth of 2 or 3 cm; the 〉63-mm fraction was examined shipboard for benthic foraminifera. Individual foraminifers were extracted for adenosine triphosphate (ATP) using a luciferin-luciferase assay, which indicated the total ATP content per specimen; that data was converted to organic carbon. Foraminiferal biomass and density varied substantially (~2-53 mg C m-2; ~3,600-44,500 individuals m-2, respectively) and inconsistently with water depth. For example, although two ~1000-m deep sites were geographically separated by only ~75 km, the foraminiferal biomass at one site was relatively low (~9 mg C m-2) while the other site had the highest foraminiferal biomass (~53 mg C m-2). Although most samples from Sigsbee Plain (〉3000 m) had low biomass, one Sigsbee site had 〉20 mg foraminiferal C m-2. The foraminiferal community from all sites (i.e., bathyal and abyssal locales) was dominated by agglutinated, rather than calcareous or tectinous, species. Foraminiferal density never exceeded that of metazoan meiofauna at any site. Foraminiferal biomass, however, exceeded metazoan meiofaunal biomass at five of the ten sites, indicating that foraminifera constitute a major component of the Gulf’s deep-water meiofaunal biomass.
    Description: Funded by Minerals Management Service contract 1435-01-99-CT-30991 to G.T. Rowe (Texas A&M University).
    Keywords: Foraminifera ; Meiofauna ; Biomass ; Deep sea ; USA ; Gulf of Mexico
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  • 16
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    Impact of intentionally injected carbon dioxide hydrate on deep-sea benthic foraminiferal survival (2009)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Authors, 2009. This is the author's version of the work. It is posted here by permission of Blackwell for personal use, not for redistribution. The definitive version was published in Global Change Biology 15 (2009): 2078-2088, doi:10.1111/j.1365-2486.2008.01822.x.
    Description: Sequestration of carbon dioxide (CO2) in the ocean is being considered as a feasible mechanism to mitigate the alarming rate in its atmospheric rise. Little is known, however, about how the resulting hypercapnia and ocean acidification may affect marine fauna. In an effort to understand better the protistan reaction to such an environmental perturbation, the survivorship of benthic foraminifera, which is a prevalent group of protists, was studied in response to deep-sea CO2 release. The survival response of calcareous, agglutinated, and thecate foraminifera was determined in two experiments at ~3.1 and 3.3 km water depth in Monterey Bay (California, USA). Approximately five weeks after initial seafloor CO2 release, in situ incubations of the live-dead indicator CellTracker Green were executed within seafloor-emplaced pushcores. Experimental treatments included direct exposure to CO2 hydrate, two levels of lesser exposure adjacent to CO2 hydrate, and controls, which were far removed from the CO2 hydrate release. Results indicate that survivorship rates of agglutinated and thecate foraminifera were not significantly impacted by direct exposure but the survivorship of calcareous foraminifera was significantly lower in direct exposure treatments compared to controls. Observations suggest that, if large scale CO2 sequestration is enacted on the deep-sea floor, survival of two major groups of this prevalent protistan taxon will likely not be severely impacted, while calcareous foraminifera will face considerable challenges to maintain their benthic populations in areas directly exposed to CO2 hydrate.
    Description: This work was funded by the Monterey Bay Aquarium Research Institute (project 200002; to JPB), US Department of Energy grant # DE-FG02-03ER63696 (to J. P. Kennett and J.M.B.), and NSF OCE-0725966 (to J.M.B.).
    Keywords: Carbon dioxide sequestration ; CO2 injection ; Climate change ; Foraminifera ; Experiment ; Hypercapnia ; Meiofauna ; Monterey Bay ; Ocean acidification ; Protist
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  • 17
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    Combined carbonate carbon isotopic and cellular ultrastructural studies of individual benthic foraminifera : method description (2010)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2010. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 25 (2010): PA2211, doi:10.1029/2009PA001846.
    Description: Carbon isotopes of foraminiferal tests provide a widely used proxy for past oceanographic environmental conditions. This proxy can be calibrated using live specimens, which are reliably identified with observations of cell ultrastructure. Observations of ultrastructures can also be used for studies of biological characteristics such as diet and presence of symbionts. Combining biological and isotopic studies on individual foraminifera could provide novel information, but standard isotopic methods destroy ultrastructures by desiccating specimens and observations of ultrastructure require removal of carbonate tests, preventing isotope measurements. The approach described here preserves cellular ultrastructure during isotopic analyses by keeping the foraminifera in an aqueous buffer (Phosphate Buffered Saline (PBS)). The technique was developed and standardized with 36 aliquots of NBS-19 standard of similar weight to foraminiferal tests (5 to 123 μg). Standard errors ranged from ± 0.06 to ± 0.85‰ and were caused by CO2 contaminants dissolved in the PBS. The technique was used to measure δ13C values of 96 foraminifera, 10 of which do not precipitate carbonate tests. Calcareous foraminiferal tests had corrected carbon isotope ratios of −8.5 to +3.2‰. This new technique allows comparisons of isotopic compositions of tests made by foraminifera known to be alive at the time of collection with their biological characteristics such as prey composition and presence or absence of putative symbionts. The approach may be applied to additional biomineralizing organisms such as planktonic foraminifera, pteropods, corals, and coccolithophores to elucidate certain biological controls on their paleoceanographic proxy signatures.
    Description: Support was provided by NSF grants OCE‐0550396 (to J.B.M.), OCE‐0551001 (to J.M.B.), and OCE‐ 0550401 (to A.E.R.).
    Keywords: Foraminifera ; Ultrastructure ; Carbon isotopes
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  • 18
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    Climate-driven range extension of Amphistegina (protista, foraminiferida) : models of current and predicted future ranges (2013)
    Public Library of Science
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 8 (2013): e54443, doi:10.1371/journal.pone.0054443.
    Description: Species-range expansions are a predicted and realized consequence of global climate change. Climate warming and the poleward widening of the tropical belt have induced range shifts in a variety of marine and terrestrial species. Range expansions may have broad implications on native biota and ecosystem functioning as shifting species may perturb recipient communities. Larger symbiont-bearing foraminifera constitute ubiquitous and prominent components of shallow water ecosystems, and range shifts of these important protists are likely to trigger changes in ecosystem functioning. We have used historical and newly acquired occurrence records to compute current range shifts of Amphistegina spp., a larger symbiont-bearing foraminifera, along the eastern coastline of Africa and compare them to analogous range shifts currently observed in the Mediterranean Sea. The study provides new evidence that amphisteginid foraminifera are rapidly progressing southwestward, closely approaching Port Edward (South Africa) at 31°S. To project future species distributions, we applied a species distribution model (SDM) based on ecological niche constraints of current distribution ranges. Our model indicates that further warming is likely to cause a continued range extension, and predicts dispersal along nearly the entire southeastern coast of Africa. The average rates of amphisteginid range shift were computed between 8 and 2.7 km year−1, and are projected to lead to a total southward range expansion of 267 km, or 2.4° latitude, in the year 2100. Our results corroborate findings from the fossil record that some larger symbiont-bearing foraminifera cope well with rising water temperatures and are beneficiaries of global climate change.
    Description: This work was supported by grants from the German Science Foundation (DFG; www.dfg.de) to ML and SL (LA 884/10-1, LA 884/5-1).
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  • 19
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    And on top of all that… coping with ocean acidification in the midst of many stressors (2015)
    The Oceanography Society
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    Publication Date: 2022-05-25
    Description: Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 2 (2015): 48-61, doi:10.5670/oceanog.2015.31.
    Description: Oceanic and coastal waters are acidifying due to processes dominated in the open ocean by increasing atmospheric CO2 and dominated in estuaries and some coastal waters by nutrient-fueled respiration. The patterns and severity of acidification, as well as its effects, are modified by the host of stressors related to human activities that also influence these habitats. Temperature, deoxygenation, and changes in food webs are particularly important co-stressors because they are pervasive, and both their causes and effects are often mechanistically linked to acidification. Development of a theoretical underpinning to multiple stressor research that considers physiological, ecological, and evolutionary perspectives is needed because testing all combinations of stressors and stressor intensities experimentally is impossible. Nevertheless, use of a wide variety of research approaches is a logical and promising strategy for improving understanding of acidification and its effects. Future research that focuses on spatial and temporal patterns of stressor interactions and on identifying mechanisms by which multiple stressors affect individuals, populations, and ecosystems is critical. It is also necessary to incorporate consideration of multiple stressors into management, mitigation, and adaptation to acidification and to increase public and policy recognition of the importance of addressing acidification in the context of the suite of other stressors with which it potentially interacts.
    Description: Funding for research on acidification and multiple stressors was provided by NOAACSCOR NA10NOS4780138 to DLB, NASA NNX14AL8 to JS, NSF OCE-1219948 to JMB, NSF OCE-927445 and OCE-1041062 to LAL, NSF EF-1041070 to W-JC, a Linnaeus grant from the Swedish Research Councils VR and Formas to SD, NSF EF-0424599 to SCD, NSF OCE-1041038 to UP, NSF EF-1316113 to BAS, NSF ANT-1142122 to AET, NSF OCE-1316040 to AMT, and the NOAA Ocean Acidification Program Office to BP, LMM, and WCL.
    Repository Name: Woods Hole Open Access Server
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  • 20
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    Inter-­comparison of the potentially active prokaryotic communities in the halocline sediments of Mediterranean deep-sea hypersaline basins (2015)
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    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Extremophiles 19 (2015): 949-960, doi:10.1007/s00792-015-0770-1.
    Description: The sediment microbiota of the Mediterranean deep-sea anoxic hypersaline basins (DHABs) are understudied relative to communities in the brines and halocline waters. In this study, the active fraction of the prokaryotic community in the halocline sediments of L’ Atalante, Urania, and Discovery DHABs was investigated based on extracted total RNA and 454 pyrosequencing of the 16S rRNA gene. Bacterial and archaeal communities were different in the sediments underlying the halocline waters of the three habitats, reflecting the unique chemical settings of each basin. The relative abundance of unique operational taxonomic units (OTUs) was also different between deep-sea control sediments and sediments underlying DHAB haloclines, suggesting adaptation to the steep DHAB chemical gradients. Only a few OTUs were affiliated to known bacterial halophilic and/or anaerobic groups. Many OTUs, including some of the dominant ones, were related to aerobic taxa. Archaea were detected only in few halocline samples, with lower OTU richness relative to Bacteria, and were dominated by taxa associated with methane cycling. This study suggests that, while metabolically active prokaryotic communities appear to be present in sediments underlying the three DHABs investigated, their diversity and activity are likely to be more reduced in sediments underlying the brines.
    Description: This work was supported by NSF OCE- 0849578 to VE and JB and OCE-1061391 to JB and VE. MP was supported by the WHOI postdoctoral scholarship program. KAK was partially supported by the University of Thessaly through a sabbatical in 2013.
    Description: 2016-07-16
    Keywords: Bacteria ; Archaea ; cDNA ; Activity ; L’ Atalante ; Urania ; Discovery ; Anoxic
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