Dataset: DOC and TOC of seawater collected during CCGS John P. Tully cruises in the northeast Pacific Ocean from Vancouver Island to Station P from 2018 to 2020

ValidatedFinal no updates expectedDOI: 10.26008/1912/bco-dmo.865829.1Version 1 (2021-12-06)Dataset Type:Cruise Results

Principal Investigator: Phoebe J. Lam (University of California-Santa Cruz)

Co-Principal Investigator: Andrea J. Fassbender (National Oceanic and Atmospheric Administration)

International Collaborator, Contact: Sophia Johannessen (Fisheries and Oceans Canada, Pacific Region)

Technician: Jacqueline S. Long (Monterey Bay Aquarium Research Institute)

Technician: Cynthia Wright (Fisheries and Oceans Canada, Pacific Region)

BCO-DMO Data Manager: Dana Stuart Gerlach (Woods Hole Oceanographic Institution)


Project: Constraining Upper-Ocean Carbon Export with Biogeochemical Profiling Floats (EXPORTS BGC Floats)


Abstract

This dataset includes observations of dissolved organic carbon and total organic carbon from seawater samples collected during CCGS John P. Tully cruises from 2018 to 202 in the northeast Pacific Ocean from Vancouver Island to Station P.

Samples
Sampling was conducted aboard the CCGS John P. Tully during five cruises (2018-2020) in the northeast Pacific Ocean from Vancouver Island to Station P (50°N, 145°W). 
Fisheries and Oceans Canada (DFO) Cruise numbers: 2018-40, 2019-001, 2019-006, 2019-008, 2020-001

Seawater samples for dissolved and total organic carbon (DOC, TOC) were collected from 10 L Niskin bottles into pre-cleaned 40 mL scintillation vials, with 0.125 cm Teflon low-bleed septa.  The vials had been cleaned in Extran 300 and rinsed several times with Type I Ultrapure water. Vials were then soaked in 10% HCl for a minimum of four hours and rinsed several times with Type I Ultrapure water. Cleaned vials were allowed to dry and were then baked at 450°C for a minimum of 5 hours. Septa were briefly washed in 10% HCl, rinsed with Type I Ultrapure water and allowed to air dry.

Samples for TOC were collected directly from the spigot of the Niskin bottle. Samples for DOC were filtered through a Millipore Opticap XL Durapore 0.22 µm inline filter cartridge (Product No. KVGLA04HH3) attached to the spigot. Vials were rinsed three times with sample water and then filled to about three-quarter capacity, to avoid breakage during freezing. The samples were quick-frozen immediately after collection, using a stainless-steel freezer block, and then stored frozen at -20°C until analysis.

DOC and TOC were measured at the Institute of Ocean Sciences, using a Shimadzu TOC-L DOC/TOC analyzer (measurement reproducibilty of ± 1.5 %), following Standard Operating Procedure 7 from Chapter 4 in Dickson et al. (2007), with the following modifications: 1) sulphuric acid was used in place of phosphoric acid to reduce vitrification of the column with saline samples; and 2) the sparging time was increased to 150 seconds.

Standards

  • A 1000ppm standard of potassium hydrogen phthalate was prepared using Type 1 water (defined below). The standard stock solution was stored refrigerated for up to 2 months.
  • Standard dilutions were done by calibrated pipette into volumetric flasks. They were made with Type 1 water that had been further processed to reduce TOC into the 2-3 ppb range. Dilution standards have a shelf life of two weeks. The very low standard concentrations (0.1-0.5 ppm) were made in larger volume flasks to reduce the errors associated with pipetting small amounts.
  • Type I - Ultrapure, Type I water is defined by the American Society for Testing and Materials (ASTM) as having a resistivity of >18 MΩ-cm, a conductivity of <0.056 µS/cm and <50 ppb of Total Organic Carbons (TOC).
  • Low Carbon Water (LCW) is a purchased, 2 μM, reference standard used to determine the instrument blank. Miami Seawater is a purchased, 42-45 μM, reference standard used to determine when the column/instrument was running cleanly enough to measure low concentrations in seawater.

 


Related Datasets

IsRelatedTo

Dataset: Discrete C and N near Station P
Fassbender, A. J., Johannessen, S., Long, J. S., Wright, C. (2021) Dissolved and particulate carbon and nitrogen data from seawater collected during CCGS John P. Tully cruises in the northeast Pacific Ocean from Vancouver Island to Station P from 2018 to 2020. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2021-12-07 doi:10.26008/1912/bco-dmo.865893.1
IsRelatedTo

Dataset: Underway pH data near Line P
Fassbender, A. J., Long, J. S., Takeshita, Y. (2021) Underway pH of seawater sampled during CCGS John P. Tully cruises in the northeast Pacific Ocean from Vancouver Island to Station P from 2019 to 2020. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2021-12-13 doi:10.26008/1912/bco-dmo.866582.1

Related Publications

Methods

Dickson, A.G., Sabine, C.L. and Christian, J.R. (Eds.) 2007. Guide to Best Practices for Ocean CO2 Measurements. PICES Special Publication 3, 191 pp