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  • 21
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    Metazoans of redoxcline sediments in Mediterranean deep-sea hypersaline anoxic basins (2016)
    BioMed Central
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in BMC Biology 13 (2015): 105, doi:10.1186/s12915-015-0213-6
    Description: The deep-sea hypersaline anoxic basins (DHABs) of the Mediterranean (water depth ~3500 m) are some of the most extreme oceanic habitats known. Brines of DHABs are nearly saturated with salt, leading many to suspect they are uninhabitable for eukaryotes. While diverse bacterial and protistan communities are reported from some DHAB haloclines and brines, loriciferans are the only metazoan reported to inhabit the anoxic DHAB brines. Our goal was to further investigate metazoan communities in DHAB haloclines and brines. We report observations from sediments of three DHAB (Urania, Discovery, L’Atalante) haloclines, comparing these to observations from sediments underlying normoxic waters of typical Mediterranean salinity. Due to technical difficulties, sampling of the brines was not possible. Morphotype analysis indicates nematodes are the most abundant taxon; crustaceans, loriciferans and bryozoans were also noted. Among nematodes, Daptonema was the most abundant genus; three morphotypes were noted with a degree of endemicity. The majority of rRNA sequences were from planktonic taxa, suggesting that at least some individual metazoans were preserved and inactive. Nematode abundance data, in some cases determined from direct counts of sediments incubated in situ with CellTrackerTM Green, was patchy but generally indicates the highest abundances in either normoxic control samples or in upper halocline samples; nematodes were absent or very rare in lower halocline samples. Ultrastructural analysis indicates the nematodes in L’Atalante normoxic control sediments were fit, while specimens from L’Atalante upper halocline were healthy or had only recently died and those from the lower halocline had no identifiable organelles. Loriciferans, which were only rarely encountered, were found in both normoxic control samples as well as in Discovery and L’Atalante haloclines. It is not clear how a metazoan taxon could remain viable under this wide range of conditions. We document a community of living nematodes in normoxic, normal saline deep-sea Mediterranean sediments and in the upper halocline portions of the DHABs. Occurrences of nematodes in mid-halocline and lower halocline samples did not provide compelling evidence of a living community in those zones. The possibility of a viable metazoan community in brines of DHABs is not supported by our data at this time.
    Description: Supported by NSF grants OCE-0849578 to VPE and JMB, OCE-1061391 to JMB and VPE, and The Investment in Science Fund at WHOI.
    Keywords: Athalassohaline ; Bryozoa ; CellTrackerTM Green ; Discovery ; L’Atalante ; Loricifera ; Meiofauna ; Nematoda ; Ultrastructure ; Urania
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 22
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    Keystone Arctic paleoceanographic proxy association with putative methanotrophic bacteria (2018)
    Nature Publishing Group
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 10610, doi:10.1038/s41598-018-28871-3.
    Description: Foraminifera in sediments exposed to gas-hydrate dissociation are not expected to have cellular adaptations that facilitate inhabitation of chemosynthesis-based ecosystems because, to date, there are no known endemic seep foraminifera. To establish if foraminifera inhabit sediments impacted by gas-hydrate dissociation, we examined the cellular ultrastructure of Melonis barleeanus (Williamson, 1858) from the Vestnesa gas hydrate province (Arctic Ocean, west of Svalbard at ~79 °N; ~1200-m depth; n = 4). From sediments with gas hydrate indicators, living M. barleeanus had unusual pore plugs composed of a thick, fibrous meshwork; mitochondria were concentrated at the cell periphery, under pore plugs. While there was no evidence of endosymbioses with prokaryotes, most M. barleeanus specimens were associated with what appear to be Type I methanotrophic bacteria. One foraminifer had a particularly large bolus of these microbes concentrated near its aperture. This is the first documented instance of bona fide living M. barleeanus in gas-hydrate sediments and first documentation of a foraminifer living in close association with putative methanotrophs. Our observations have implications to paleoclimate records utilizing this foundational foraminiferal species.
    Description: JMB was funded by a WHOI Independent Study Award (Mellon Grant), with partial support from NSF grant OCE-1634469. GP and CAGE 15-2 cruise were supported by the Research Council of Norway through CAGE Center for Excellence in Arctic Gas Hydrate Environment and Climate project 223259 and NORCRUST (project number 255150).
    Repository Name: Woods Hole Open Access Server
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  • 23
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    Active eukaryotes in microbialites from Highborne Cay, Bahamas, and Hamelin Pool (Shark Bay), Australia (2014)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in The ISME Journal 8 (2014): 418–429, doi:10.1038/ismej.2013.130.
    Description: Microbialites are organosedimentary structures that are formed through the interaction of benthic microbial communities and sediments and include mineral precipitation. These lithifying microbial mat structures include stromatolites and thrombolites. Exuma Sound in the Bahamas, and Hamelin Pool in Shark Bay, Western Australia are two locations where significant stands of modern microbialites exist. Although prokaryotic diversity in these structures is reasonably well documented, little is known about the eukaryotic component of these communities and their potential to influence sedimentary fabrics through grazing, binding and burrowing activities. Accordingly, comparisons of eukaryotic communities in modern stromatolitic and thrombolytic mats can potentially provide insight into the coexistence of both laminated and clotted mat structures in close proximity to one another. Here we examine this possibility by comparing eukaryotic diversity based on Sanger and high-throughput pyrosequencing of small subunit ribosomal RNA (18S rRNA) genes. Analyses were based on total RNA extracts as template to minimize input from inactive or deceased organisms. Results identified diverse eukaryotic communities particularly stramenopiles, Alveolata, Metazoa, Amoebozoa, and Rhizaria within different mat types at both locations, as well as abundant and diverse signatures of eukaryotes with 〈80% sequence similarity to sequences in GenBank. This suggests presence of significant novel eukaryotic diversity, particularly in hypersaline Hamelin Pool. There was evidence of vertical structuring of protist populations and foraminiferal diversity was highest in bioturbated/clotted thrombolite mats of Highborne Cay.
    Description: This work was funded by grant OCE-0926421 to JMB and VPE and OCE-0926372 to RES.
    Keywords: Eukaryote ; Protist ; Stromatolite ; Microbialite ; Thrombolite ; 18S rRNA ; Diversity ; Foraminifera ; Hamelin Pool ; Highborne Cay
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 24
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    Technical Note : Towards resolving in situ, centimeter-scale location and timing of biomineralization in calcareous meiobenthos – the calcein–osmotic pump method (2015)
    Copernicus Publications on behalf of the European Geosciences Union
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biogeosciences 12 (2015): 5515-5522, doi:10.5194/bg-12-5515-2015.
    Description: Insights into oceanographic environmental conditions such as paleoproductivity, deep-water temperatures, salinity, ice volumes, and nutrient cycling have all been obtained from geochemical analyses of biomineralized carbonate of marine organisms. However, we cannot fully understand geochemical proxy incorporation and the fidelity of such in species until we better understand fundamental aspects of their ecology such as where and when these (micro)organisms calcify. Here, we present an innovative method using osmotic pumps and the fluorescent marker calcein to help identify where and when calcareous meiofauna calcify in situ. Method development initially involved juvenile quahogs (Mercenaria mercenaria); subsequent method refinement involved a neritic benthic foraminiferal community. Future applications of this method will allow determining the in situ growth rate in calcareous organisms and provide insights about microhabitats where paleoceanographically relevant benthic foraminifera actually calcify.
    Description: This research was funded by WHOI’s Ocean Life Institute, WHOI’s Ocean and Climate Change Institute, by a Gori Fellowship (to F. Mezzo), The Investment in Science Fund at WHOI (to J. M. Bernhard) and the Robert W. Morse Chair for Excellence in Oceanography (to J. M. Bernhard). Ship time was provided by US NSF grant OCE-1219948 to J. M. Bernhard.
    Repository Name: Woods Hole Open Access Server
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  • 25
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    Supplemental files from “Metazoans of redoxcline sediments in Mediterranean deep-sea hypersaline anoxic basins” (Bernhard et al., submitted, BMC Biology). (2015)
    Details
    Publication Date: 2022-05-25
    Description: Link provides access to supplemental tables and figures to our manuscript regarding metazoans of redoxcline sediments in Mediterranean deep-sea hypersaline anoxic basins (DHABs). Specimens shown in supplemental figures are loriciferans collected from control and lower halocline sediments of L'Atalante Basin and Discovery Basin. Further details appear in Bernhard et al. (submitted).
    Repository Name: Woods Hole Open Access Server
    Type: Dataset , Still Image
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  • 26
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    Mercury-pollution induction of intracellular lipid accumulation and lysosomal compartment amplification in the benthic foraminifer Ammonia parkinsoniana (2016)
    Public Library of Science
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    Publication Date: 2022-05-25
    Description: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The definitive version was published in PLoS One 11 (2016): e0162401, doi:10.1371/journal.pone.0162401.
    Description: Heavy metals such as mercury (Hg) pose a significant health hazard through bioaccumulation and biomagnification. By penetrating cell membranes, heavy metal ions may lead to pathological conditions. Here we examined the responses of Ammonia parkinsoniana, a benthic foraminiferan, to different concentrations of Hg in the artificial sea water. Confocal images of untreated and treated specimens using fluorescent probes (Nile Red and Acridine Orange) provided an opportunity for visualizing the intracellular lipid accumulation and acidic compartment regulation. With increased Hg over time, we observed an increased number of lipid droplets, which may have acted as a detoxifying organelle where Hg is sequestered and biologically inactivated. Further, Hg seems to promote the proliferation of lysosomes both in terms of number and dimension that, at the highest level of Hg, resulted in cell death. We report, for the first time, the presence of Hg within the foraminiferal cell: at the basal part of pores, in the organic linings of the foramen/septa, and as cytoplasmic accumulations.
    Description: The research for this paper was partially made possible by the financial support from the PRIN 2010-2011 Ministero dell’Istruzione, dell’Università e della Ricerca (MIUR) (protocollo 2010RMTLYR) to RC. JMB acknowledges support from The Investment in Science Fund at WHOI. BG, JRE, AJ, LZ, and EMP were supported in part by the Office of Biological and Environmental Research, US Department of Energy (DOE) as part of the Mercury Science Focus Area at Oak Ridge National Laboratory, which is managed by UT-Battelle LLC for the DOE under contract DE-AC05-00OR22725.
    Repository Name: Woods Hole Open Access Server
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  • 27
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    Comparison of two methods to identify live benthic foraminifera : a test between Rose Bengal and CellTracker Green with implications for stable isotope paleoreconstructions (2007)
    American Geophysical Union
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    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography, 21 (2006): PA4210, doi:10.1029/2006PA001290.
    Description: The conventional method to distinguish live from dead benthic foraminifers uses Rose Bengal, a stain that reacts with both live and dead cytoplasm. CellTracker Green CMFDA is a fluorogenic probe causing live cells to fluoresce after proper incubation. To determine the more accurate viability method, we conducted a direct comparison of Rose Bengal staining with CellTracker Green labeling. Eight multicore tops were analyzed from Florida Margin (SE United States; 248-751 m water depths), near Great Bahama Bank (259-766 m), and off the Carolinas (SE United States; 220 m, 920 m). On average, less than half the Rose Bengal-stained foraminifera were actually living when collected. Thus, while Rose Bengal can significantly overestimate abundance, combined analyses of CellTracker Green and Rose Bengal can provide insights on population dynamics and effects of episodic events. Initial stable isotope analyses indicate that the CellTracker Green method does not significantly affect these important paleoceanographic proxies.
    Description: Funding for this research was provided by the National Science Foundation Research Experience for Undergraduates Program (grant #OCE-0139423; PI, D. McCorkle, WHOI) and NSF grants OCE-9911654 and OCE-0351029.
    Keywords: Benthic foraminifera ; Viability assay ; Stable isotopes ; Epifluorescence microscopy
    Repository Name: Woods Hole Open Access Server
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  • 28
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    A culture-based calibration of benthic foraminiferal paleotemperature proxies : δ18O and Mg/Ca results (2010)
    Copernicus Publications on behalf of the European Geosciences Union
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    Publication Date: 2022-05-25
    Description: © The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution 3.0 License. The definitive version was published in Biogeosciences 7 (2010): 1335-1347, doi:10.5194/bg-7-1335-2010
    Description: Benthic foraminifera were cultured for five months at four temperatures (4, 7, 14 and 21 °C) to establish the temperature dependence of foraminiferal calcite δ18O and Mg/Ca. Two Bulimina species (B. aculeata and B. marginata) were most successful in terms of calcification, adding chambers at all four temperatures and reproducing at 7 and 14 °C. Foraminiferal δ18O values displayed ontogenetic variations, with lower values in younger individuals. The δ18O values of adult specimens decreased with increasing temperature in all but the 4 °C treatment, exhibiting a relationship consistent with previous δ18O paleotemperature calibration studies. Foraminiferal Mg/Ca values, determined by laser ablation inductively coupled plasma mass spectrometry, were broadly consistent with previous Mg/Ca calibration studies, but extremely high values in the 4 °C treatment and higher than predicted values at two of the other three temperatures make it challenging to interpret these results.
    Description: Funding was provided by US NSF OCE-0647899 to DCM and JMB, and by the Swedish Research Council (grant no 621-2005-4265), the Lamm Foundation, and the Engkvist Foundation to HLF. A Fulbright fellowship to HLF together with traveling grants from G¨oteborg University, the Crafoord Foundation, and the Royal Physiographic Society in Lund enabled HLF’s Postdoc stay and subsequent visits to WHOI.
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  • 29
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    Corrigendum to "A culture-based calibration of benthic foraminiferal paleotemperature proxies: δ18O and Mg/Ca results" published in Biogeosciences, 7, 1335–1347, 2010 (2011)
    Copernicus Publications on behalf of the European Geosciences Union
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    Publication Date: 2022-05-25
    Description: © The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution 3.0 License. The definitive version was published in Biogeosciences 8 (2011): 1521, doi:10.5194/bg-8-1521-2011.
    Repository Name: Woods Hole Open Access Server
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  • 30
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    An endobiont-bearing allogromiid from the Santa Barbara Basin : implications for the early diversification of foraminifera (2006)
    American Geophysical Union
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    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 111 (2006): G03002, doi:10.1029/2005JG000158.
    Description: Our current understanding of paleoecology and paleoceanography is largely based on the superb Phanerozoic fossil record of foraminiferan protists. The early history of the group is unresolved, however, because basal foraminiferans (allogromiids) are unmineralized and thus fossilize poorly. Molecular-clock studies date foraminiferal origins to the Neoproterozoic, but the deep sea – one of Earth’s most extensive habitats and presently a significant fraction of basal foraminiferal diversity— was probably anoxic at that time and, until now, anaerobic allogromiids were unknown. Molecular, cell and ecological analyses reveal the presence of a previously unknown allogromiid inhabiting anoxic, sulfidic deep-sea sediments (Santa Barbara Basin, California, USA). The fact that the new foraminifer harbors prokaryotic endobionts implicates symbiogenesis as a driving force in early foraminiferal diversification.
    Description: The Wadsworth Center’s Electron Microscopy, Biochemistry, and Molecular Genetics Core facilities, as well as its National Biotechnology Resource for the Visualization of Biological Complexity (supported by a NIH BRTP/NCRR grant) are gratefully acknowledged. Funded by NASA Exobiology NRA-01-01-EXB-057 (to J.M.B.); W. Storrs Cole Memorial Research Award (Geological Society of America, to J.M.B.); NSF DEB0445181 (to S.S.B.).
    Keywords: Foraminifera ; Santa Barbara Basin ; Symbiosis
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