SHIPBOARD STUDIES OF THE CALIFORNIA CURRENT SYSTEM OFF CENTRAL CALIFORNIA

Baldo Marinovic (Institute of Marine Sciences, University of California, Santa Cruz), Francisco Chavez (Monterey Aquarium Research Institute), and Curtis Collins (Naval Postgraduate School)

Link to NOAA Strategic Plan: NOAA's Mission Goal 1: Protect, Restore, and Manage the Use of Coastal and Ocean Resources through Ecosystem-based Management; Goal 2: Understand Climate Variability and Change to Enhance Society's Ability to Plan and Respond

RESEARCH OBJECTIVES AND SPECIFIC PLANS TO ACHIEVE THEM

In cooperation with the NMFS, we proposed to continue quarterly shipboard measurements along CalCOFI Lines 60 and 67 through August 2007. The NOAA Ship David Starr Jordan would make measurements for the fall cruise and the NOAA Ship MacArthur II will be utilized in the summer cruise. Measurements In Fall 2006 and Summer 2007 will consist of CTD/rosette casts, plankton tows, VMADCP current observations, and continuous underway measurements of sea surface and meteorological parameters. Seawater will be assayed for nutrients (nitrate, nitrite, phosphate and silicate). Water samples in the upper 200 m will also be assayed for chlorophyll-a, primary production, phytoplankton taxonomy and cell counts. Vertical and horizontal zooplankton sampling will include standard bongo oblique tows to 210 m depth as well as surface manta tows. Samples will be preserved in 10% buffered formalin/seawater and processed post-cruise in the laboratory. Biovolume displacements will be initially determined and then samples will be archived at SIO where taxon-specific processing will be conducted by various research groups. All data collected on the fall and summer cruises will be made available as soon as possible to other researchers via web-based archives and technical reports.

RESEARCH ACCOMPLISHMENTS

During the period between July 2006 and June 2007, in cooperation with the NMFS, quarterly shipboard measurements along central California were continued in an effort to further understand the relationship between physical circulation and biological consequences in this critical region that is the site for the majority of the nutrient input to the surface waters of the California Current System.

Additionally this work also supported the collection and analysis of chlorophyll-a and nutrients from the northern lines occupied by the NOAA Ship David Starr Jordan during the Winter and Spring of 2007.

Measurements Taken During the Fall 2006 and Summer 2007 cruises included:
•            Continuous underway sampling of SST, SSS, Fluorescence, pCO2, and meteorological parameters
•            CTD/rosette casts including assays for four nutrients (nitrate, nitrite, phosphate and silicate), chlorophyll-a, primary production, phytoplankton taxonomy and cell counts
•            Bongo tows (oblique) to 210m to sample macrozooplankton/icthyoplankton—processed for zooplankton biovolume and krill abundance and species composition and subsequently archived for further taxonomic analysis with NMFS La Jolla

Fig. 1 Contours of (a) temperature (oC), (b) salinity, (c) density anomaly (kg m-3), and (d) oxygen (μm kg-1) fields along the line of hydrographic stations from Moss Landing (on the left) to Point Reyes. The blue lines indicate the locations of the corner hydrographic stations (CTDs 18/19 and 23/24). Contour intervals for panels a-d are 1oC, 0.1, 0.2 kg m-3, and 20 μm kg-1, respectively, except that the (nearly) oxygen minimum contour of 10 μm kg-1 is highlighted in red in panel d.