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  • 1
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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
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 2
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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
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 3
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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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  • 4
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    Nutritional sources of meio- and macrofauna at hydrothermal vents and adjacent areas: Natural-abundance radiocarbon and stable isotope analyses (2019)
    Inter Research
    Details
    Publication Date: 2022-05-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nomaki, H., Uejima, Y., Ogawa, N. O., Yamane, M., Watanabe, H. K., Senokuchi, R., Bernhard, J. M., Kitahashi, T., Miyairi, Y., Yokoyama, Y., Ohkouchi, N., & Shimanaga, M. Nutritional sources of meio- and macrofauna at hydrothermal vents and adjacent areas: Natural-abundance radiocarbon and stable isotope analyses. Marine Ecology Progress Series, 622, (2019): 49-65, doi:10.3354/meps13053.
    Description: Deep-sea hydrothermal vents host unique marine ecosystems that rely on organic matter produced by chemoautotrophic microbes together with phytodetritus. Although meiofauna can be abundant at such vents, the small size of meiofauna limits studies on nutritional sources. Here we investigated dietary sources of meio- and macrofauna at hydrothermal vent fields in the western North Pacific using stable carbon and nitrogen isotope ratios (δ13C, δ15N) and natural-abundance radiocarbon (Δ14C). Bacterial mats and Paralvinella spp. (polychaetes) collected from hydrothermal vent chimneys were enriched in 13C (up to -10‰) and depleted in 14C (-700 to -580‰). The δ13C and Δ14C values of dirivultid copepods, endemic to hydrothermal vent chimneys, were -11‰ and -661‰, respectively, and were similar to the values in the bacterial mats and Paralvinella spp. but distinct from those of nearby non-vent sediments (δ13C: ~-24‰) and water-column plankton (Δ14C: ~40‰). In contrast, δ13C values of nematodes from vent chimneys were similar to those of non-vent sites (ca. -25‰). Results suggest that dirivultids relied on vent chimney bacterial mats as their nutritional source, whereas vent nematodes did not obtain significant nutrient amounts from the chemolithoautotrophic microbes. The Δ14C values of Neoverruca intermedia (vent barnacle) suggest they gain nutrition from chemoautotrophic microbes, but the source of inorganic carbon was diluted with bottom water much more than those of the Paralvinella habitat, reflecting Neoverruca’s more distant distribution from active venting. The combination of stable and radioisotope analyses on hydrothermal vent organisms provides valuable information on their nutritional sources and, hence, their adaptive ecology to chemosynthesis-based ecosystems.
    Description: We are grateful to the crews and scientists of the R/V ‘Natsushima’ and the ROV ‘Hyper-Dolphin’ of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) during the NT12-10, NT13-09 and NT14-06 cruises, and the R/V ‘Kaimei’ and the KM-ROV of JAMSTEC during the KM-ROV training cruise. We thank Yuki Iwadate for her help on sample preparations and 2 anonymous reviewers and the editor, who provided helpful comments on an earlier version of this manuscript. This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan (Scientific Research C 26440246 to M.S.), the Japan Society for the Promotion of Science (Invitational fellowships for research in Japan, S14032 to J.M.B.), the WHOI Robert W. Morse Chair for Excellence in Oceanography, and The Investment in Science Fund at WHOI.
    Keywords: Meiofauna ; Dirivultid copepods ; Nematodes ; Paralvinella ; Neoverruca ; Nutrition ; Natural-abundance radiocarbon ; Stable carbon and nitrogen isotope ratios
    Repository Name: Woods Hole Open Access Server
    Type: Article
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