Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
  • BCO-DMO Processing Description
  • Problem Description
• Data Files
• Related Publications
• Related Datasets
• Parameters
• Instruments
• Project Information
• Funding

125-milliliter (mL) high-density polyethylene (HDPE) oblong wide-mouth bottles certified to meet EPA performance-based standards for metals, cyanide, and fluoride (Fisher Scientific product number 05-721-147) were used. The bottles had been previously used on GP17-OCE (R/V Roger Revelle cruise RR2214). Bottles were pretreated in one of five treatments: 1.) no further conditioning, 2.) 1-week soak in low nutrient surface seawater, 3.) 2-week soak in low nutrient surface seawater 4.) 1-week soak in milli-Q water or 5.) a 2-week soak in milli-Q water.

After the treatment, the bottles were rinsed with milli-Q water 3 times and allowed to dry in a fume hood. All of the bottles were then filled with low-nutrient surface seawater collected from the North Atlantic (39˚ 46.406' N, 70˚ 53.065' W on October 10, 2019). A 20-liter (L) carboy was filled with the seawater (that had previously been poisoned to ~0.04% HgCl2) by filtering through a 0.8/0.2-micrometer (um) AcroPak™ 1000 filter (Pall Laboratories, Port Washington, New York USA, product number 1515-002). After filtering, the carboy was shaken vigorously to ensure it was well mixed and allowed to equilibrate overnight. The practical salinity of the water was 34.992, and the initial TA was determined to be 2299.68 ±0.59 (N=5). More details can be found in Woosley et al. (submitted).

Instrumentation:
Samples were analyzed in the lab for total alkalinity using a custom-designed open cell titration with non-linear least squares fitting designed and built by the laboratory of Andrew G. Dickson (University of California, San Diego) and described in detail in Dickson et al. (2003).

Data were quality controlled and flagged for any known analytical issues that occurred for a given sample.

- Imported original file "HDPE Lab Test Submit to BCODMO.xlsx" into the BCO-DMO system.
- Marked "-999" as a missing data value (missing data are empty/blank in the final csv file).
- Renamed fields to comply with BCO-DMO naming conventions.
- Converted the date-time column to ISO 8601 format.
- Saved final file as "957694_v1_ta_hdpe_bottle_storage_test.csv".

NSF Award Abstract
The oceans help to slow climate change by absorbing about a quarter of the carbon dioxide (CO2) produced by burning of fossil fuels and other human activities. The Pacific and Southern Oceans are known to take up and store significant amounts of anthropogenic CO2, but many questions regarding the amount, variability, and biogeochemical and ecological impacts remain unanswered. This research will focus on answering some of those questions in two areas of the Pacific by analyzing samples for total CO2, total alkalinity, and pH on two GEOTRACES cruises, GP17-OCE and GP17-ANT. The project will support several undergraduate student researchers and create educational modules on ocean acidification for general public and K-12 students.

On the GP17-OCE expedition in the south Pacific, sub-decadal scale variability in the uptake of CO2 and resulting decrease in pH (termed ocean acidification) will be examined by comparing data collected on this expedition with data from prior occupations of the line in 1991, 2005 and 2014. An extended multilinear regression technique will be used to separate natural variability from human induced changes. The second expedition, GP17-ANT, covers the Amundsen Sea, an area with few prior carbon measurements. This sea is perennially ice-covered with several seasonal polynyas (areas of open water surrounded by sea ice) and exhibits complex water circulation making the contribution to the global carbon cycle uncertain. The data collected from this expedition will examine several hypotheses regarding how carbon is taken up, mixed, and recirculated in the region, how glacial ice melt, sea ice, and biological productivity influence the carbon cycle, and provide baseline measurements against future data to determine changes in the carbon cycle of the region over time. Both expeditions will leverage the myriad of other parameters being measured, particularly trace metals such as iron and zinc, to examine how cycling of carbon and trace metals are interlinked through pH.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.