Dataset: GP15 Nitrate d15N and d18O Leg 2

Name: Nitrate d15N and d18O from Niskin bottle samples collected on Leg 2 (Hilo, HI to Papeete, French Polynesia) of the US GEOTRACES Pacific Meridional Transect (PMT) cruise (GP15, RR1815) on R/V Roger Revelle from October to November 2018
Published: 2024-05-21
Keywords: nitrogen cycle, nitrate isotopes, Pacific Ocean, GP15, GEOTRACES, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.928099.1

Spatial Extent: N:18.9065 E:-151.9861 S:-20 W:-155.2581

GP15 Pacific Meridional Transect along 152W

Temporal Extent: 2018-10-25 - 2018-11-23

Project:

Collaborative Research: US GEOTRACES PMT: Investigating geochemical tracers of the Pacific nitrogen cycle and budget (PMT Nitrate)

US GEOTRACES Pacific Meridional Transect (GP15) (U.S. GEOTRACES PMT)

Program:

U.S. GEOTRACES (U.S. GEOTRACES)

Principal Investigator:

Daniel M. Sigman (Princeton University)

Co-Principal Investigator:

Karen L. Casciotti (Stanford University)

Scientist:

Jen Karolewski (Stanford University)

Rian Lawrence (Stanford University)

Dario Marconi (Princeton University)

Alfredo Martinez Garcia (Max Planck Institute for Chemistry)

Wentao Wang (Princeton University)

Technician:

Sergey Oleynik (Princeton University)

BCO-DMO Data Manager:

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

Version:

Version Date:

2024-05-21

Restricted:

Yes

Release Date:

2024-07-01

Validated:

Yes

Current State:

Final no updates expected

Nitrate d15N and d18O from Niskin bottle samples collected on Leg 2 (Hilo, HI to Papeete, French Polynesia) of the US GEOTRACES Pacific Meridional Transect (PMT) cruise (GP15, RR1815) on R/V Roger Revelle from October to November 2018

Abstract:

These data include nitrate δ15N and δ18O along US GEOTRACES GP15, a meridional transect at ~152°W in the Pacific Ocean. The Pacific hosts significant rates of all the fluxes that are relevant to the global N cycle: the N budget fluxes (those that either generate or consume fixed N; N2 fixation and denitrification) as well as the N fluxes from the internal N cycle (those that generate or consume nitrate but leave the fixed N pool unaltered; nitrate regeneration and assimilation). The nitrate δ15N and δ18O provide a useful tool to separate and possibly quantify the overlapping impacts of all these co-occurring processes. GP15 was a 60-day research cruise that took place in 2018 along a transect form Alaska to Tahiti at 152° W on board of the R/V Revelle. The cruise was completed in two legs (RR1814 and RR1815), which started on the 18th of September and on the 24th of October 2018, respectively. This dataset includes data from Leg 2 (RR1815). Leg 1 data (RR1814) are provided in a separate, related dataset.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2024-05-21	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.928099.1	2024-06-13

Methods & Sampling

Seawater samples were collected using a 36-bottle ODF (Ocean Data Facility) conventional rosette equipped with 10.4-liter (L) Niskin bottles.

HDPE nalgene bottles were acid washed (10% HCl) and rinsed three times (3X) with high-purity water (HPW) before being shipped at sea. Sampling at sea followed the GEOTRACES cookbook indications for nitrate isotopes. Bottles and caps were rinsed three times (3X) with seawater samples from the Niskin before being filled up to shoulder. Samples were then stored kept upright and frozen at -20 degrees Celsius (°C).

Seawater samples were processed in accordance with the published Denitrifier Method (Casciotti et al., 2002). All isotope analyses were performed on a MAT253 Thermo IRMS equipped with a custom-sample preparation system. With this system, we were able to achieve an overall standard deviation of 0.04 per mil for d15N-NO3 analyses and 0.11 per mil for d18O-NO3 analyses. Individual data points have been averaged with standard deviations reported. Please see the papers cited under Related Publications for equations applied to derive final data.

Data Processing Description

Raw data (for mass 45/44 and 46/44) are generated by the MAT253 Thermo IRMS and are calibrated into nitrate d15N and d18O using a correction scheme developed in Excel.

Quality Flags:
All data are of good quality and have thus been assigned a flag of '1'.

BCO-DMO Processing

- Imported original file "RR1815_data_Sigman.xlsx" into the BCO-DMO system.
- Marked "NaN" as a missing data value (missing data are empty/blank in the final CSV file).
- Renamed fields to comply with BCO-DMO naming conventions.
- Created date-time fields in ISO 8601 format.
- Removed empty fields (Gear_ID and Rosette_Position).
- Saved final file as "928099_v1_gp15_nitrate_d15n_d18o_leg2.csv".

Data Files

File
928099_v1_gp15_nitrate_d15n_d18o_leg2.csv (Comma Separated Values (.csv), 60.26 KB) MD5:4fca2d2801134bcdfc4c28f8b8d952cf Primary data file for dataset ID 928099, version 1

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1736652

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
RR1815	GP15 GP15 Leg 2 33RR20180918 PMT US GEOTRACES PMT	2018-10-24	R/V Roger Revelle	Gregory A. Cutter (Chief Scientist) Karen L. Casciotti (Co-Chief Scientist) Phoebe J. Lam (Co-Chief Scientist)	data info

Instruments

Isotope-ratio Mass Spectrometer

Supplied Name: MAT253 Thermo IRMS equipped with a custom-sample preparation system

Supplied Description:

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).

Niskin bottle

Supplied Name: 10.4L Niskin bottles deployed on the ODF 36-bottle rosette

Supplied Description:

Instrument Type

Generic Name: Niskin bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/

Generic Description:

A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Station_ID	Station number	unitless	station
Event_ID	GEOTRACES event number	unitless	event
Start_Date_UTC	Date of sampling (start) Format: %Y%m%d	unitless	date
Start_Time_UTC	Time of sampling (start) (UTC) Format: %H%M	unitless	time
Start_ISO_DateTime_UTC	Date and time of sampling in ISO 8601 format (start) (UTC) Format: %Y-%m-%dT%H:%MZ	unitless	ISO_DateTime_UTC
End_Date_UTC	Date of sampling (end) Format: %Y%m%d	unitless	date
End_Time_UTC	Time of sampling (end) (UTC) Format: %H%M	unitless	time
End_ISO_DateTime_UTC	Date and time of sampling in ISO 8601 format (end) (UTC) Format: %Y-%m-%dT%H:%MZ	unitless	ISO_DateTime_UTC
Start_Latitude	Latitude of sampling (start); positive values = North	decimal degrees	lat
Start_Longitude	Longitude of sampling (start); negative values = West	decimal degrees	lon
End_Latitude	Latitude of sampling (end); positive values = North	decimal degrees	lat
End_Longitude	Longitude of sampling (end); negative values = West	decimal degrees	lon
Sample_ID	GEOTRACES sample ID	unitless	sample
Sample_Depth	Depth in meters (calculated from pressure and latitude)	meters (m)	depth
NITRATE_15_14_D_DELTA_BOTTLE_w2kmnp	Nitrate d15N in per mil versus air	per mil versus air	dN15_NO3
SD1_NITRATE_15_14_D_DELTA_BOTTLE_w2kmnp	Standard deviation of NITRATE_15_14_D_DELTA_BOTTLE_w2kmnp	per mil versus air	dN15_NO3
Flag_NITRATE_15_14_D_DELTA_BOTTLE_w2kmnp	Quality flag for NITRATE_15_14_D_DELTA_BOTTLE_w2kmnp	unitless	q_flag
NITRATE_18_16_D_DELTA_BOTTLE_dksgvb	Nitrate d18O in per mil versus VSMOW	per mil versus VSMOW	d18O_NO3
SD1_NITRATE_18_16_D_DELTA_BOTTLE_dksgvb	Standard deviation of NITRATE_18_16_D_DELTA_BOTTLE_dksgvb	per mil versus VSMOW	d18O_NO3
Flag_NITRATE_18_16_D_DELTA_BOTTLE_dksgvb	Quality flag for NITRATE_18_16_D_DELTA_BOTTLE_dksgvb	unitless	q_flag
Comment	Indicates for which samples we performed nitrite removal	unitless	comment

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Database

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Dataset: GP15 Nitrate d15N and d18O Leg 2