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OAS accession Detail for 0278844
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| accessions_id: | 0278844 | archive |
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| Title: | Planktic foraminifer tissue and shell d15N from net tows on R/V S.A. Agulhas II cruises VOY016 and VOY019 in the Southern Ocean south of Africa during 2015-2016 (NCEI Accession 0278844) |
| Abstract: | This dataset contains biological, chemical, optical, and physical data collected on R/V S.A. Agulhas II during cruises VOY016 and VOY019 in the Indian Ocean and South Atlantic Ocean from 2015-07-27 to 2016-05-09. These data include Nitrate, Nitrogen, d15N, d15N measured in biota, dN15_NO3, density, depth, dissolved Oxygen, fluorescence, mixed layer depth, nitrate plus nitrite, particulate organic nitrogen, salinity calculated from CTD primary sensors, taxon_code, and water temperature. The instruments used to collect these data include CTD Sea-Bird, Elemental Analyzer, Isotope-ratio Mass Spectrometer, and Plankton Net. These data were collected by Daniel M. Sigman of Princeton University as part of the "Understanding the nitrogen isotopes of planktonic foraminifera: A modern Sargasso Sea study (N Isotopes Foraminifera)" project. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2020-03-13. The following is the text of the dataset description provided by BCO-DMO: Planktic foraminifer tissue and shell d15N from net tows in the African sector Dataset Description: This dataset synthesizes net-tow data (foraminifera and zooplankton measurements) with tow-depth seawater measurements (physical and chemical properties) and surface measurements of bulk suspended particulate organic nitrogen (PON) collected from the underway intake (7 m depth). |
| Date received: | 20200313 |
| Start date: | 20150727 |
| End date: | 20160509 |
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| West boundary: | 0.048 |
| East boundary: | 38.476 |
| North boundary: | -40.959 |
| South boundary: | -53.994 |
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| Submitting institution: | Biological and Chemical Oceanography Data Management Office |
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| Supplementary information: | Acquisition Description: Planktic foraminifera were collected by towing a 200-μm-mesh plankton net for 90 min at a target depth within the upper mixed layer. Approximately 90% of the tow material was preserved in a 5-10% pH-buffered formalin solution and stored at 4°C until sorting for foraminifera (Ren et al., 2012). The remaining 10% was size fractionated and frozen at −20°C for element and isotope analysis of zooplankton. During each tow, bulk (>0.3 µm) suspended PON and nitrate samples were collected from the underway intake (at 7 m depth) and frozen at −80°C and −20°C, respectively, until isotope analysis. In situ (i.e., tow-depth) nitrate samples and auxiliary hydrographic data come from CTD casts performed on station before the start of each net tow. Foraminifera were separated by species, rinsed briefly with Milli-Q and crushed open to expose (non-shell-bound) tissue. Tissue N was converted to nitrate using the persulfate oxidation method (Nydahl, 1978; Knapp et al., 2005). Remnant shell material (having been oxidatively cleaned) was transferred, rinsed six times with Milli-Q and oven dried at 50°C. Shell samples were then dissolved with hydrochloric acid to release shell-bound organics for persulfate oxidation (Nydahl, 1978; Knapp et al., 2005). For both tissue- and shell-derived nitrate (from persulfate oxidation) as well as seawater nitrate, samples were measured for concentration by chemiluminescence (Braman & Hendrix, 1989) and N isotope composition using the denitrifier method and gas chromatography−isotope ratio mass spectrometry (GC-IRMS) (Sigman et al., 2001; Casciotti et al., 2002; Weigand et al., 2016). The N isotope composition of bulk PON and size-fractionated zooplankton were measured by elemental analyser-IRMS. The isotopic composition of N₂O was measured either at Princeton University (USA) or the Max Planck Institute for Chemistry (MPIC; Germany) by GC-IRMS using a Thermo MAT 253 mass spectrometer with a purpose-built on-line N₂O extraction and purification system. Bulk PON and size-fractionated zooplankton samples were measured at the University of Cape Town using a Thermo Scientific FLASH 2000 elemental analyzer coupled to a Thermo Scientific Delta V Plus mass spectrometer. Hydrographic data were acquired by a Sea-Bird conductivity-temperature depth sensor during each cast. See methods section of Smart et al. (2020) for more detail. |
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| Metadata version: | 1 |
| Keydate: | 2023-05-28 04:20:34+00 |
| Editdate: | 2023-05-28 04:21:18+00 |