Dataset: South Pacific Nitrate Isotopes
Deployment: ZHNG02RR

Nitrate and Oxygen isotope measurements from CLIVAR line P16S in 2005

Principal Investigator:

Patrick Rafter (University of California-Irvine, UC Irvine)

Co-Principal Investigator:

Peter DiFiore (Princeton University)

Daniel M. Sigman (Princeton University)

Contact:

Patrick Rafter (University of California-Irvine, UC Irvine)

BCO-DMO Data Manager:

Ms Dicky Allison (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

CAREER: Nitrate Isotopes and Biogeochemistry; A Plan for coupling (CAREER)

Current State:

Final with updates expected

Version:

working toward final

Deployment Synonyms:

P16S, 33RR200501, P16S_2005a, P16

Version Date:

2016-07-13

Data URL:

https://osprey.bco-dmo.org/dataset-deployment/651758/data

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Description

Nitrogen and Oxygen isotopes in Nitrate (NO3) measurements from samples retrieved from CLIVAR P16S in 2005.

These data are discussed in Rafter et al., 2013. Coupled nitrate nitrogen and oxygen isotopes and organic matter remineralization in the Southern and Pacific Oceans, J. Geophys. Res. Oceans, 118, 4781-4794, doi: 10.1002/jgrc.20316.

Methods & Sampling

Dataset acquisition description

Seawater samples between 65 S and 20 S were collected by the science crew of the CLIVAR program (CLIVAR P16S during January/February 2005). Seawater samples between 8 S and 7N were collected by the science crew of NOAA ship R/V Ka’imimoana. Nutrients were measured on board (nitrate, nitrite, phosphate, and silicate), and 50 mL samples were frozen. Samples from the Chilean Margin were acquired in February 2010 and frozen, and nutrient measurements were made at Rutgers University shortly afterward.

Deployment-specific acquisition description

This deployment was correct for MOST of the dataset. There were three samples from three other cruises, aboard NOAA's R/V Ka'imimoana.

Data Processing Description

Dataset Processing Description

All samples were analyzed at Princeton University for nitrate N and O isotopes using the "denitrifier" method [Sigman et al., 2001; Casciotti et al., 2002]. In this method, nitrate and nitrite are converted to N2O gas using denitrifying bacteria and the N and O isotopes of this N2O are measured on an isotope ratio mass spectrometer. These measurements are referenced to atmospheric N2 or Vienna Standard Mean Ocean Water, respectively, with analytical precision of +/-0.2% for nitrate d15N and +/-0.3% for nitrate d18O for in-house seawater-based reference material. The reported measurements are of nitrate + nitrite. Nitrite is generally less than 1% or less of the nitrate + nitrite at all stations and for simplicity the analyses are referred to below as "nitrate."

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-0447570	NSF Division of Ocean Sciences

Instruments

Isotope-ratio Mass Spectrometer

Supplied Name: Isotope Ratio Mass Spectrometer

Supplied Description:

These measurements are referenced to atmospheric N2 or Vienna Standard Mean Ocean Water, respectively, with analytical precision of 60.2% for nitrate 15N and 60.3% for nitrate 18O for in-house seawater-based reference material.

Instrument Type

Generic Name: Isotope-ratio Mass Spectrometer

Acronym: IR Mass Spec; IRMS

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/

Generic Description:

The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer).

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
date_sample	sampling data; yyyymmdd	unitless	date
lat	latitude	decimal degrees; South is negative	lat
lon	longitude	decimal degrees; West is negative	lon
mixed_layer_depth	depth range where active mixing has homogenized the water	meters	depth_mixed_layer
press	sampling depth	decibars	press
NO3_umol_kg	nitrate concentration	micromols per kilogram	NO3_umol_kg
NO3d15N	ratio of stable isotopes 15N:14N used to differentiate Nitrate from different sources	per mil	dN15_NO3
NO3d180	ratio of stable isotopes O18:O16 used to differentiate Nitrate from different sources	per mil	d18O_NO3
temp	water temperature	degrees Celsius	temp
sal	salinity; pss-78	dimensionless	sal
pot_density	potential density; also known as sigma-theta	kilograms per meter cubed-1000	sigma_theta
potemp	potential temperature	degrees Celsius	potemp
O2_umol_kg	dissolved oxygen	micromoles per kilogram	O2_umol_kg
NO2	Nitrite	micromoles per kilogram	NO2
PO4	Phosphate	micromoles per kilogram	PO4
SiO3	Silicate	micromoles per kilogram	SiO3
D15_18	D(15-18) is the difference between the nitrogen and oxygen isotopic composition of nitrate	per mil	no_bcodmo_term

Database

Contribute Data

Dataset: South Pacific Nitrate Isotopes
Deployment: ZHNG02RR

Dataset acquisition description

Deployment-specific acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: South Pacific Nitrate IsotopesDeployment: ZHNG02RR

Dataset acquisition description

Deployment-specific acquisition description

Dataset Processing Description

Dataset: South Pacific Nitrate Isotopes
Deployment: ZHNG02RR