Table of Contents

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

Samples 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). 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 [Juranek et al., 2010], intake lines between the anticorrosive sea chest and the sampling port were purged with bleach and freshwater between every cruise.  Since the samples were collected underway on a vessel moving ~24 knots and samples for all parameters were collected by a single shiprider, ship transit from the time that the location coordinates were recorded to the time of actual sampling could reflect a transit distance offset from the recorded location of up to 40 kilometers.

Details of collection event issues (dataset Notes field):

• Missing info on duplicate:  A number of data entries are missing timestamp and location information for duplicates because separate times were not recorded at the time of collection.  Since the ship moves at ~24 knots, differences between the duplicate samples may represent real spatial variations between the times the duplicate samples were collected.
• Intake temp issue:  The intake temperature was not working until 2010-02-17 on the TJ9 cruise, so 23 of the reported temperatures are derived from TSG -0.3 (approximate correction for inline warming)
• Missing TSG data and/or GPS signal: On the Tokyo_0 cruise, 7 entries are missing TSG data and 2 additional are missing GPS information as well as TSG data. 
• No GPS data: On the Tianjin_1 cruise, six entries did not have GPS available.

Methods are described in detail in Clayton et al. (in preparation for JGR: Oceans). Discrete samples were collected from the underway seawater system (10 m depth). Chlorophyll samples were filtered onto Whatman GF/F. Both chlorophyll and nutrient samples were frozen for later analysis in a shore-based laboratory. Samples were measured in the Marine Chemistry Laboratory at the University of Washington. For nutrients, analyses and calibration follow the protocols of the WOCE Hydrographic Program using a Seal Analytical AA3. For chlorophyll, analysis is acetone extraction and fluorometric detection on a Turner Designs TD-700 fluorometer.

BCO-DMO Processing:

• Converted datetimes to ISO Date UTC format
• Converted Longitudes to 0 to 180 scale
• Rounded fields to 4 decimal places
• Shortened Notes column (for better display) and listed details above in Acquisition description
• Adjusted parameter names to comply with database requirements. 
• Removed units from field names and added to Parameter Description metadata section. 
• Added a conventional header with dataset name, PI names, version date.
• Missing data identifier of  'nd' used ('nd' is BCO-DMO system default missing data identifier). 

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.