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OAS accession Detail for 0291486
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Title: Results from nutrient limitation assessments quantifying the level of Si, N, and Fe stress being experienced by phytoplankton in samples collected on EXPORTS cruise DY131 in the North Atlantic during May 2021 (NCEI Accession 0291486)
Abstract: This dataset contains biological and physical data collected on RRS Discovery during cruise DY131 in the North Atlantic Ocean from 2021-05-06 to 2021-05-27. These data include PAR and depth nominal. The instruments used to collect these data include CTD Sea-Bird, GO-FLO Bottle, Lachat QuikChem 8500 flow injection analysis system, and PerkinElmer Tri-Carb 3110TR low activity liquid scintillation analyzer. These data were collected by Mark A. Brzezinski of University of California-Santa Barbara, Bethany D. Jenkins of University of Rhode Island, and Kristen Buck of University of South Florida as part of the "Collaborative Research: Diatoms, Food Webs and Carbon Export - Leveraging NASA EXPORTS to Test the Role of Diatom Physiology in the Biological Carbon Pump (Diatoms and carbon export)" project and "EXport Processes in the Ocean from Remote Sensing (EXPORTS)" program. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2023-04-13.

The following is the text of the dataset description provided by BCO-DMO:

32Si and 14C Production - Experiments - from DY131

Dataset Description:
Depth profiles in the euphotic zone of nutrient (nitrate, silicate, phosphate) concentrations, profiles of silicic acid uptake rates, and assessment of limitation by Si, N, and Fe on both silicic acid uptake and carbon fixation.

See the related dataset ( https://www.bco-dmo.org/dataset/893293 ) for the profile data.
Date received: 20230413
Start date: 20210506
End date: 20210527
Seanames:
West boundary: -14.976
East boundary: -14.51
North boundary: 49.234
South boundary: 48.782
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Submitter:
Submitting institution: Biological and Chemical Oceanography Data Management Office
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Supplementary information: Acquisition Description:
Seawater samples were collected using an epoxy coated CTD-rosette mounted with Go-Flo samplers and a Sea-Bird Electronics CTD (SBE9plus). Go-Flo bottles were transferred to a trace metal clean van for subsampling into polypropylene tubes (nutrients), polypropylene bottle (biogenic silica and particulate carbon and nitrogen) or TM acid-cleaned polycarbonate incubation bottles (Si-32 & C-14 incubation experiments).

Nutrient samples were filtered through 0.2 micrometer (μm) polycarbonate filters and frozen at -20° Celsius (C). Samples for biogenic silica concentrations were size fractionated by serial filtration through 5 μm and 0.6 μm polycarbonate filters Filters were stored frozen at -20°C. Particulate organic carbon and nitrogen were measured on samples from experiments examining the effect of added Fe and Si on carbon fixation. These samples were filtered through precombusted GFF filters placed in glass scintillation vials and frozen at -20°C.

Samples for silicic acid uptake profiles were spiked with the radioisotope Si-32. Nutrient limitation assays were performed on pairs of samples where the rate of silicic acid uptake (Si-32) or carbon fixation (C-14 in paired light/dark bottles) were determined in unaltered controlled samples and in samples augmented with either silicic acid (20 μM), nitrate (20 μM) or iron chloride (1 nanomolar (nM)). All samples were incubated on deck in simulated in situ incubators cooled with flowing surface seawater for 24 hours. Profiles sampled six depths from near surface to the 1% light level. Nutrient limitation assays were performed at the 40% and 10% light levels.

Particles from incubated samples were size fractionated by serial filtration through 5 μm and 0.6 μm 25-millimeter (mm) polycarbonate filters. For C-14 incubations, total radioactivity in each sample was determined by sampling 100 μl of sample seawater prior to filtration. Filters from Si-32 incubations were placed on plastic planchettes and dried before covering with mylar film and stored for analysis ashore using low-level beta counters (Riso Inc). Filters from C-14 incubations were acidified in glass scintillation vials, scintillation cocktail (Ultima Gold XR) was added followed by liquid scintillation counting. Total radioactivity samples received 100 μL of b-phenethylamine and 5 mL of scintillation cocktail prior to analysis at sea using a Tri-Carb 3110TR scintillation counter.

Biogenic silica concentrations were determined by NaOH digestion followed by colorimetric analysis of the resulting dissolved Si. Particulate organic carbon and nitrogen samples were analyzed by Dumas combustion. Nutrient concentrations were determined by flow injection using a Lachat Instruments QuikChem 8500 Series 2 anayzer.

For more information, see the Protocol documents attached as Supplemental Files and https://msi.ucsb.edu/facilities-services/analytical-lab/services .
Availability date:
Metadata version: 1
Keydate: 2024-04-21 03:22:39+00
Editdate: 2024-04-21 03:28:36+00