Full details for collection and analyses of underway Chl samples are provided by Go\u00f1i et al., submitted . Brief summaries are provided below.
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Samples for this study were collected aboard RV Oceanus using the surface underway scientific system.
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Aboard the vessel we had access to uncontaminated seawater and collected samples at specific times that allowed us to determine location (latitude and longitude) and seawater characteristics (temperature and salinity) from the ships\u2019 navigation and sensor panels. We used a semi-automated filtration system (SAFS) described by Go\u00f1i et al., (2019) connected to Oceanus surface underway water to collect particulate samples for chlorophyll analyis. Surface underway water was connected to the SAFS through a manual flow-control valve via opaque polyethylene tubing.\u00a0 A fly wheel flow meter was placed in-line and connected to a laptop computer using a data acquisition system to measure and record flows during the filtration stage. A switching valve with 8 ports was placed downstream from the flow meter and controlled by the laptop.\u00a0 Under stand-by conditions, flow was directed to the \u2018waste\u2019 port, which was fitted with unobstructed tubing that drained into one of the ship\u2019s sinks and flowed back to sea.\u00a0 For Chlorophyll (Chl) measurements, samples were collected via the SAFS using 25 mm pre-combusted GF/F membranes placed inside stainless steel filter holders. Once filters were fitted in each of the sample ports, the filtration program was started to collect samples at selected intervals.
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Once the filtration run was completed, the filter housings were removed from the SAFS, opened, and each individual filter placed in a closed container and stored in -80oC freezer until analyses.\u00a0 Each sample was assigned a specific time stamp (start-end of filtration process) that coincided with the ship\u2019s clock and allowed us to retrieve location and oceanographic data for each sample, as well as determine an overall filtration volume, which was used to calculate total chlorophyll concentrations once analyses were completed.
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Samples were processed and analyzed following the method outlined in Strickland and Parsons (1972). Brifely, chlorophyll a concentrations were determined using the method of where samples were extracted in 90% acetone for 48 hours at -20\u00b0C in the dark and measured fluorometrically using a Turner Designs 10-AU fluorometer.
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References cited: Strickland & Parson, 1972; Go\u00f1i et al., 2019; Go\u00f1i et al., submitted.
These data are part of a manuscript submitted to Continental Shelf Research:
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Go\u00f1i, M.A., Welch, K.A., Alegria, E., Alleau Y., Watkins-Brandt, K., White, A.E. (submitted) Wintertime Particulate Organic Matter Distributions in Surface Waters of the Northern California Current System. Continental Shelf Research.
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The data are shown in figures in the manuscript (Figure 7) and in supplementary information (Figure 4S).
Temperature and salinity data were acquired at approximately 1 Hz and then binned to correspond to the time stamps of discrete Chl samples collected by the semi-automated filtration system (SAFS, see above). Navigation data were integrated into the sensor data set using the sample filtration time stamps to provide latitude and longitude information for each surface underway sample.
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BCO-DMO processing notes:
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\n- Adjusted column names to comply with database requirements
\n- Added ISO_DateTime_UTC column
\n- Cleaned up Time_Date_PST column: 3916->2016, 16->2016
\n- Converted positive longitude values in western hemisphere to negative (-180 to 180 notation)
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