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).
