DIC: Water was sampled using a 5 L niskin bottle centered at 1 m with a bottle length of 0.7 m. DIC was measured on mercuric chloride poisoned samples by acidification and subsequent quantification of released CO2 using a CO2 detector (Li-Cor 7000). DIC samples were collected following recommended procedures {Dickson et al., 2007} and measurements were calibrated against Certified Reference Materials provided by Dr. A. G. Dickson at Scripps Institution of Oceanography (SIO), University of California, San Diego (UCSD).

pH: Water was sampled using a 5 L niskin bottle centered at 1 m with a bottle length of 0.7 m. pH was measured spectrophotometrically {Clayton and Byrne, 1993} in triplicate at standard temperature (25°C) immediately following collection. pH samples were collected following recommended procedures {Dickson et al., 2007}.

Secchi Depth: Secchi depth was measured in duplicate using a 20 cm disk with four alternating white and black quadrants (Cole Parmer #EW-05492-00) by lowering the disk until no longer visible and recording the depth.

Salinity: Water was sampled using a 5 L niskin bottle centered at 1 m with a bottle length of 0.7 m. Salinity was measured using a calibrated handheld digital refractometer (Atago PAL-06S), using a refractometer (Vista A366ATC), or using a Guideline Portasal 8410A all according to manufacturer’s instructions and calibrated against known reference materials. In situ salinity at the same depth was measured using a YSI Pro30.

Turbidity: Turbidity was measured in duplicate on discrete samples using a calibrated handheld turbidimeter (Orion AQ4500).

Dissolved Oxygen: Oxygen was measured optically in situ and atmospheric pressure measured near the sea surface using a calibrated probe (YSI ProODO) using manufactures recommendations.

Chlorophyll: Water was sampled using a 5 L niskin bottle centered at 1 m with a bottle length of 0.7 m. Methods described in Johnson et al. 2010: Chlorophyll concentrations were measured by filtering 25 mL of seawater sample onto a 0.22 µm pore size polycarbonate filter using gentle vacuum (<100 mm Hg) and extracting in 100% MeOH at -20°C in the dark for >24 h following (Holm-Hansen and Riemann, 1978). Fluorescence was measured using a Turner Designs 10-AU fluorometer following (Welschmeyer, 1994) that was calibrated against a standard chlorophyll solution (Ritchie, 2008).

Bacteria: Bacterioplankton (i.e. ‘bacteria’) were enumerated using a FACSCalibur flow cytometer (Becton Dickinson) and populations characterized as previously described (Johnson et al., 2010). Briefly, cells were excited with a 488 nm laser (15 mW Ar) and inelastic forward (<15°) scatter, inelastic side (90°) scatter (SSC), green (530 ± 30 nm) fluorescence, orange fluorescence (585 ± 42 nm), and red fluorescence (> 670 nm) emissions were measured. Bacterioplankton were quantified by staining the samples with the nucleic acid stain SYBR Green –I (Molecular Probes Inc.) (Marie et al., 1997).

Nutrients: Water was filtered through a 0.22 µm Sterivex cartridge filter, Millipore #SVGPL10RC using a peristaltic pump input line at 1 m for later nutrient analysis (NO3, NO2, PO4, SiOH4) and water was placed into duplicate HCl-cleaned HDPE bottles (VWR#414004-110) and stored at -80°C until later analysis using an Astoria-Pacific A2 autoanalyzer following the manufacturer’s recommended protocols running each replicate sample in duplicate.

Certified reference materials were used to verify protocols (Inorganic Ventures: QCP-NT, QCP-NUT-1, CGSI1-1). The detection limit was NO2 = 0.05 µM, NO3 = 0.1 µM, PO4 = 0.05 µM, SiOH4 = 0.2 µM). Values measured below these limits are reported as zero.

Temperature: Water was sampled using a 5 L niskin bottle centered at 1 m with a bottle length of 0.7 m. Temperature was measured in duplicate using NIST traceable thermocouples (VWR#23609-232). In situ water temperature at the same depth was measured using a YSI Pro30.

PICO2017.csv