Dataset: Planktic foraminifer shell d15N from sediment traps

Name: Planktic foraminifer shell d15N from Oceanic Flux Program (OFP) sediment traps in the Sargasso Sea
Published: 2018-10-02
Keywords: biota, oceans

Cite This Dataset

DOI:10.1575/1912/bco-dmo.747341.1

Spatial Extent: N:31.833 E:-64.167 S:31.833 W:-64.167

Temporal Extent: 2009-11-23 - 2010-10-26

Project:

Understanding the nitrogen isotopes of planktonic foraminifera: A modern Sargasso Sea study (N Isotopes Foraminifera)

Principal Investigator:

Daniel M. Sigman (Princeton University)

Contact:

Sandi M. Smart (Stellenbosch University)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2018-10-02

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Planktic foraminifer shell d15N from Oceanic Flux Program (OFP) sediment traps in the Sargasso Sea

Abstract:

Planktic foraminifer shell d15N from sediment traps in the Sargasso Sea (off Bermuda) in the western subtropical North Atlantic. Sediment traps from 500 m, 1500 m, and 3200 m water depth (31°50’N, 64°10’W).

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2018-10-02	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.1575/1912/bco-dmo.747341.1	2020-01-10

Description

Data published in:
Smart, S.M., H. Ren, S.E. Fawcett, R. Schiebel, M. Conte, P.A. Rafter, K.K. Ellis, M.A. Weigand, S. Oleynik, G.H. Haug, D.M. Sigman (2018). Ground-truthing the planktic foraminifer-bound nitrogen isotope paleo-proxy in the Sargasso Sea, Geochimica et Cosmochimica Acta, doi: https://doi.org/10.1016/j.gca.2018.05.023

Methods & Sampling

Planktic foraminifer shells were picked from Oceanic Flux Program (OFP) sediment traps at 500 m, 1500 m, and 3200 m water depth (Conte et al., 2001; Conte and Weber, 2014). After crushing and the appropriate cleaning steps (Ren et al., 2012; Ren et al., 2015), shell-bound N was released by dissolution with hydrochloric acid, and organic N converted to nitrate using a basic persulfate oxidising reagent (POR; a potassium persulfate/sodium hydroxide solution) (Nydahl, 1978; Knapp et al., 2005). The "denitrifier method" was used to convert sample nitrate to N₂O gas for isotope analysis (Sigman et al., 2001; Casciotti et al., 2002; Weigand et al., 2016). See methods section of Smart et al. (2018) for more details of sample collection, isotope analysis and data quality.

The isotopic composition of N₂O was measured at Princeton University by GC-IRMS using a Thermo MAT 253 mass spectrometer with a purpose-built on-line N₂O extraction and purification system. See methods section of Smart et al. (2018) for more details of sample collection, isotope analysis and data quality.

Data Processing Description

Data Processing: Isotope ratio measurements were referenced against automated injections of N₂O from a gas cylinder, and then calibrated to N₂ in air using two international reference materials IAEA-N3 and USGS-34 that were included in every run. An in-house N₂O standard was also measured along with each batch of samples to monitor mass spectrometry. Oxidized samples were additionally corrected for the contribution of the N blank associated with the POR.

Missing data identifier = -999

BCO-DMO Processing:
- modified parameter names (replaced spaces w/ underscores);
- formatted date from mm/dd/yyyy to yyyymmdd.

Data Files

File
d15N_Shell_Traps.csv (Comma Separated Values (.csv), 4.65 KB) MD5:25c48c49f158f6dc022734ba292c63ea Primary data file for dataset ID 747341

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1060947
NSF Division of Ocean Sciences	OCE-0960802
NSF Division of Ocean Sciences	OCE-1136345

Deployments

None available yet

Instruments

Isotope-ratio Mass Spectrometer

Supplied Name: Thermo MAT 253

Supplied Description:

The isotopic composition of N₂O was measured at Princeton University by GC-IRMS using a Thermo MAT 253 mass spectrometer with a purpose-built on-line N₂O extraction and purification system.

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).

Plankton Net

Supplied Name: mesh plankton net

Supplied Description:

Living planktic foraminifera were collected for tissue N analysis from the upper 200 m of the water column using a 1-m2, 200-um-mesh plankton net aboard the R/V Atlantic Explorer during ten cruises between July 2011 and November 2013.

Instrument Type

Generic Name: Plankton Net

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/22/

Generic Description:

A Plankton Net is a generic term for a sampling net that is used to collect plankton. It is used only when detailed instrument documentation is not available.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
species	Name of species	unitless	taxon
date	Date of sample collection (format: yyyymmdd)	unitless	date
num_individuals_500m	Number of individuals collected at 500 meters	unitless	number
num_individuals_1500m	Number of individuals collected at 1500 meters	unitless	number
num_individuals_3200m	Number of individuals collected at 3200 meters	unitless	number
num_individuals_TOTAL	Total number of individuals	unitless	number
d15N	d15N (per mil vs. AIR) is the nitrogen isotopic composition of a sample expressed in delta notation (d15N in units of per mil, ‰) relative to atmospheric N2, where d15N = {[(15N/14N)sample/(15N/14N)atmN2] – 1} × 1000.	per mil	d15N
Total_N	Total Nitrogen	nanomoles (nmol)	N
weight	Weight of sample	milligrams (mg)	weight
N_content	Nitrogen content	nanomoles per milligram (nmol/mg)	N