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OAS accession Detail for 0277860
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Title: PO4, NO3, NO2 surface concentrations along the US GEOTRACES North Atlantic Transect from the R/V Knorr KN199-04, KN199-05 cruises in the subtropical N. Atlantic during 2010 (U.S. GEOTRACES NAT project) (NCEI Accession 0277860)
Abstract: This dataset contains chemical data collected on R/V Knorr during cruises KN199-04 and KN199-05 in the North Atlantic Ocean from 2010-10-17 to 2010-11-25. These data include Nitrate, Nitrite, and reactive phosphorus (PO4). The instruments used to collect these data include GeoFish Towed near-Surface Sampler. These data were collected by Gregory Cutter of Old Dominion University as part of the "U.S. GEOTRACES North Atlantic Transect (U.S. GEOTRACES NAT)" project and "U.S. GEOTRACES (U.S. GEOTRACES)" program. The Biological and Chemical Oceanography Data Management Office (BCO-DMO) submitted these data to NCEI on 2020-04-10.

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

Nanomolar concentrations of PO4, NO3, NO2 (surface)

Dataset Description:
Nanomolar concentrations of PO4, NO3, NO2 - Surface Transects.
Date received: 20200410
Start date: 20101017
End date: 20101125
Seanames:
West boundary: -78.995
East boundary: -9.605
North boundary: 38.347
South boundary: 16.855
Observation types:
Instrument types:
Datatypes:
Submitter:
Submitting institution: Biological and Chemical Oceanography Data Management Office
Collecting institutions:
Contributing projects:
Platforms:
Number of observations:
Supplementary information: Acquisition Description:
Filtered (0.4 µm) water samples from the Geotraces surface tow-fish and water from the upper 200 m water column (GEOTRACES Carousel/GoFlo system) were analyzed on an Astoria Pacific 300 series gas-segmented continuous flow nutrient auto-analyzer modified with 200 cm liquid waveguide capillary cells (LWCC; World Precision Instruments). Nitrate was reduced to nitrite using a Cd-column, then determined spectrophotometrically following formation of a highly colored dye, but slightly modified for use with a liquid core waveguide (see references below). Nitrite is measured separately without the Cd column and then subtracted from the combined nitrate+nitrite sample. The molybdenum blue method modified for use with liquid core wave guide was used for phosphate (references below).

Recovery for phosphate measurements for LWCC relative to the MAGIC method is 100 ± 15 % for concentrations below 100 nmol/L. The relative standard deviation for nine measurements of 5 nmol/L phosphate was 1.6 %. The relative standard deviation for nine measurements of 60 nM phosphate was 0.9 %. LWCC detection limit (3 x σ of blank) for phosphate was 0.5 nmol/L, 1.5 nmol/L for nitrate and 0.6 nmol/L for nitrite.

Upper working limit for LWCC:
Phosphate 100 nmol/L
Nitrate 200 nmol/L
Nitrite 200 nmol/L
Availability date:
Metadata version: 1
Keydate: 2023-05-04 04:38:23+00
Editdate: 2023-05-04 04:39:06+00