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OAS accession Detail for 0277398
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Title: Nitrate (d15N and d18O) and nitrite (d15N) isotopic data, and corresponding hydrographic data from R/V Knorr cruise KN182-09 in the Peruvian Oxygen Deficient Zone in 2005 (N2O Cycling project) (NCEI Accession 0277398)
Abstract: This dataset contains chemical and physical data collected on R/V Knorr during cruise KN182-09 from 2005-10-18 to 2005-11-10. These data include Nitrate, Nitrite, depth, dissolved Oxygen, nitrate plus nitrite, reactive phosphorus (PO4), salinity calculated from CTD primary sensors, sigma-theta, water pressure, and water temperature. The instruments used to collect these data include Isotope-ratio Mass Spectrometer, Niskin bottle, and Nutrient Autoanalyzer. These data were collected by Karen L. Casciotti of Woods Hole Oceanographic Institution as part of the "Biogeochemistry of nitrous oxide cycling in the eastern tropical South Pacific (N2O Cycling)" project. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2023-01-23.

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

Nitrate (d15N and d18O) and nitrite (d15N) isotopic data, and corresponding hydrographic data.

Dataset Description:
Nitrogen and oxygen isotopic data from a 2005 cruise on R/V Knorr (KN182-09) in the Peruvian Oxygen Deficient Zone.
Date received: 20230123
Start date: 20051018
End date: 20051110
Seanames:
West boundary: -79.3
East boundary: -75.07
North boundary: -11
South boundary: -17.67
Observation types:
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Submitter:
Submitting institution: Biological and Chemical Oceanography Data Management Office
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Number of observations:
Supplementary information: Acquisition Description:
Sampling and Analytical Methodology:
Samples were collected from Niskin bottles, syringe filtered through 0.2 um pore-size capsule filters and frozen immediately in 60 mL HDPE bottles. Samples were stored frozen until analysis. Nitrate and nitrite concentrations were measured on separate aliquots by auto analyzer at the WHOI nutrient facility.

Samples were initially analyzed for nitrate + nitrite d15N and d18O using the denitrifier method (Sigman et al., 2001; Casciotti et al., 2002), then nitrite d15N and d18O were subtracted out according to Casciotti and McIlvin (2007). Later, the samples were reanalyzed for nitrate d15N and d18O using the denitrifier method after treatment with sulfamic acid using the method of Granger and Sigman (2009). These latter analyses, which we believe to be more accurate and precise, are reported here. Samples were analyzed in duplicate and are reported as the mean and standard deviation of replicate measurements. Typical precision for these analyses is 0.2-0.3 for d15N and 0.3-0.5 for d18O.

Samples were analyzed for nitrite d15N and d18O using the azide method (McIlvin and Altabet, 2005). Nitrite d18O data are not reported because it was determined that samples may have undergone O atom equilibration with water during storage (Casciotti et al., 2007). Typical precision for these analyses is 0.3-0.5 for d15N and 0.3-0.5 for d18O.

All isotopic measurements were conducted on a Thermo Finnigan Delta PLUS XP isotope ratio mass spectrometer.
Availability date:
Metadata version: 1
Keydate: 2023-04-03 04:45:41+00
Editdate: 2023-04-03 04:48:59+00