Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

This dataset includes triple oxygen isotopes (δ17O and δ18O), a tracer of gross primary production; oxygen/argon dissolved gas ratios, a tracer of net community production or carbon export; temperature and salinity. Samples were collected during transects across the Pacific Ocean from Hong Kong to Long Beach, CA on commercial container ships starting in 2008.

Related Dataset: Carbonate chemistry and isotopes

Samples for TOI and O2/Ar analysis were collected from shipboard seawater intake (10 m depth) on basin-wide transects of the North Pacific between Hong Kong and Long Beach, California onboard the M/V OOCL Tianjin and the M/V OOCL Tokyo (each individual transect has a unique Cruise ID) starting in 2008 Samples were collected into pre-evacuated 500-ml flasks every ~2.5° longitude across the basin following the procedures of Emerson et al. [1999]. Sea surface temperature and salinity at the time of sample collection were determined using a Sea-Bird Electronics SBE45 thermosalinograph installed in the ship’s seawater intake. To prevent biofouling that could cause respiration in the ship’s seawater lines and contaminate O2/Ar measurements [Juranek et al., 2010], intake lines between the anticorrosive sea chest and the sampling port were purged with bleach and freshwater between every cruise.

In the laboratory, dissolved gas samples were equilibrated at room temperature for 24 hours and then drained under vacuum to remove seawater. Oxygen and argon were cryogenically extracted and separated from the remainder of the dissolved gas mixture following the procedures of Juranek and Quay [2005]. Samples were subsequently analyzed on a Finnegan MAT 253 isotope ratio mass spectrometer using 75 paired measurements of masses 32, 33, and 34 alternating with measurements of an internal standard to determine δ17O and δ18O, followed by measurements of masses 32 and 40 on a single collector to determine O2/Ar. Reported values for δ17O and δ18O are corrected for the experimentally-determined dependence on both the sample size, as described by Stanley et al., [2010], and the sample O2/Ar ratio. Measurement uncertainty for each sample batch was determined based on daily air standards, and is reported along with all sample values.

Measurement errors for δ17O and δ18O are correlated (r2 = 0.90, n = 489), resulting from mass-dependent fractionation in the sample extraction and measurement process initially reported by Hendricks et al. [2004]. To enable the correlation in these errors to be accounted for in propagating error in calculations made direction from δ17O and δ18O (i.e. gross oxygen production), we report the slope of the linear relationship between δ17O and δ18O error for each sample batch as well as the slope uncertainty.

Data is only reported for samples that meet quality control standards (any with problems in the laboratory extraction and measurement process have been replaced with NaN in the data spreadsheet). NB. NaN's were changed to nd's in the served dataset.

BCO-DMO Processing:

- added conventional header with dataset name, PI name, version date, reference information
- renamed parameters to BCO-DMO standard
- split date/time into two columns
- reformatted date from m/d/yyyy to yyyy-mm-dd
- changed NaN to nd
- changed number of significant digits to 2 (lat, lon, lon360) or 3 (sal, temp)

This project is an ongoing time-series beginning in 2008 of measurements relevant to ocean carbon cycling and productivity on basin-wide container ship transects across the North Pacific from Hong Kong to Long Beach, California, with transects made throughout the seasonal cycle beginning in October 2008. The goal of this project is to improve our understanding of the rates and mechanisms of ocean carbon uptake from the atmosphere throughout the seasonal cycle and across spatial gradients across the basin. Sampling includes both discrete samples and continuous underway measurements. Tracers sampled in this program include triple oxygen isotopes (δ17O and δ18O), a tracer of gross primary production, oxygen/argon dissolved gas ratios, a tracer of net community production or carbon export, and carbonate system parameters (pCO2, total alkalinity, DIC, and 13C-DIC) as tracers of ocean carbon uptake and carbon cycling.