The CTD sensor is lowered and raised through the water column, capturing measurements of seawater temperature, salinity, and seawater pressure

The SeaPoint sensor is lowered and raised through the water column, capturing measurements of chlorophyll-a fluorescence.

The Seabird SBE-43 sensor is lowered and raised through the water column, measuring the dissolved concentration of oxygen.

The WetLabs ECO sensor is lowered and raised through the water column, measuring the fluorescence of dissolved organic matter (FDOM).

Nutrient samples were collected directly from the Niskin-type bottles with syringes, filtered in-line (Swinnex-mounted, Whatman GF/F), and captured in acid-cleaned polyethylene tubes. Nutrient concentra- tions for nitrate + nitrite, ammonium, phosphate, and silicate were measured colorimetrically with a Bran and Luebbe AutoAnalyzer III (Hansen & Koroleff, 1999) onboard the ship within a few hours of collection. Working standards were prepared at each station and checked against certified reference material (KANSO CRM) inserted into the sample runs. Analytical detection limits were 0.03 μM for nitrate, 0.02 μM for nitrite, 0.05 μM for phosphate, and 0.1 μM for silicate. Ammonium concentrations were measured using the method of Holmes et al. (1999) with a detection limit of 0.02 μM.

• Nitrate
• nitrite
• ammonium
• phosphate
• and silicate

Samples were collected in 250-mL glass bottles, preserved with 100 μL of saturated mercuric chloride solution, capped with ground glass stoppers greased with Apiezon M, and sealed with electrical tape. Samples were then stored in the dark at 4°C until analysis at the Institute for Ocean Sciences in Sidney, British Columbia, within 10 months of collection. The coulometric DIC analysis utilized either a SOMMA or VINDTA 3D (MARIANDA) extraction system. Measurements were calibrated against certified reference materials (CRM batches 88, 115, and 133, provided by Andrew Dickson, Scripps Institute of Oceanography). Analyses of duplicate DIC samples indicated a precision of ±1 μmol kg −1 (n = 27).

• Dissolved inorganic carbon

Samples were collected in the field following the same protocol as DIC samples. Measurements of TA used open-cell potentiometric titrations with nonlinear least squares end-point determination. These measurements were calibrated against certified reference materials (CRM batches 88, 115, and 133, provided by Andrew Dickson, Scripps Institute of Oceanography). Analyses of duplicate TA samples indicated a precision of ±3 μmol kg −1 (n = 23).

• Total Alkalinity