Scientific operations on CalCOFI cruises are performed 24/7 - around the clock, 7 days a week. Scientists, technicians, and volunteers work 12hr shifts scheduled from noon to midnight or midnight to noon. Although transit times between stations can vary and are heavily influenced by sea state, transits between stations usually take 2 to 4 hours. Coastal stations spaced 20 nautical miles apart (eg. 93.50 to 93.55) take ~2hrs; offshore stations spaced 40 nautical miles apart (eg. 93.60 to 93.70) take ~4hrs. The time to complete work on a station varies as well but a typical station operations takes ~2.25hrs. Longer stations are: daily primary productivity noontime stations, Santa Monica & Santa Barbara basin stations, & DIC stations all take ~3hrs; 3500m deep CTD casts on stations 80.90, 90.90 take ~5hrs; nightly Oozeki trawl stations take ~3.5hrs. SCCOOS (9 per cruise) and shallow (<500m; 8 per cruise) stations can be significantly less than 2 hours. CalCOFI cruises operate on Pacific Standard Time (PST) on all cruises.
Each standard CalCOFI station usually includes the following:
- A Seabird 9/11plus CTD/Rosette consisting of 24 10-liter hydrographic bottles is lowered to 515 meters (depth permitting) measuring physical parameters (temperature, salinity, oxygen, fluorescence, transmittance, NO3 and PAR); bottles are closed at discrete depths isolating seawater for analysis of: oxygen concentration, salinity, nutrients, chlorophyll and phytoplankton.
- A CalBOBL (CalCOFI Bongo) standard oblique plankton tow with 300 meters of wire out, depth permitting, using paired 505 um mesh nets with 71 cm diameter openings. The technical requirements for this tow are: Descent rate of 50 meters per minute. All tows with ascending wire angles lower than 38 degrees or higher than 51 degrees in the final 100 meters of wire will be repeated. Additionally, a 45 degrees wire angle should be closely maintained during the ascent and descent of the net frame. The Bongo frame is fitted with a self-contained OPC (Optical Particle Counter) mounted inside the port side opening.
- A Manta net (neuston) tow, using a 505 um mesh net on a frame with a mouth area of 0.1333 m^2. The Manta net is towed at surface, sampling 8cm below the air-sea interface, for 15mins at ~1.5kts.
- A Pairovet (vertical) plankton tow is performed at all stations inshore of, and including station 70. The Pairovet net fishes from 70 meters to the surface (depth permitting) using paired 25 cm diameter 150 um mesh nets. The technical requirements for Pairovet tows are: Descent rate of 70 meters per minute, ascent rate of 70 meters per minute. All tows with wire angles exceeding 15 degrees during the ascent will be repeated.
- A PRPOOS (Planktonic Rate Processes in Oligotrophic Ocean Systems) vertical net tow is performed at all stations on line 90.0 and 80.0 as well as stations out to and including station 70.0 on lines 86.7 and 83.3. These stations are occupied as part of the LTER(Long Term Ecological Reserve) project. The mesh of the PRPOOS net is 202 um and the tow is a vertical cast up from 210 meters.
- Weather observations are tabulated during station supplementing continuous data collected by shipboard integrated mesurement systems (SCIMS/MET/SCS) which also collect continuous sea surface data.
- Secchi disc during daylight stations.
- Primary productivity experiment: at LAN, local apparent noon (~1130-1220), each day of the cruise, a primary productivity incubation experiment is started from the CTD cast. Eighteen samples drawn from six depths determined by a Secchi disc observation and subsequent % light level calculations are inoculated with C14. Primary production is measured as C14 uptake by samples incubated from LAN to civil twilight at 6 light levels (simulating 6 in-situ depths). Chlorophyll and phaeophytin concentrations are determined from 24hr cold acetone extraction fluorometric measurements of duplicate seawater samples. Nutrients are measured with an auto-analyzer. All radioisotope work is done in a certified, isolated, radioisotope van; all areas are wipe tested before the departure of the SIO technical staff.
- During transit between daytime stations:
- One bird observer records location and species of various sea birds.
- Two marine mammal observers visually identify marine mammals
- A multi-frequency towed hydrophone array, monitored by an acoustician, records marine mammal vocalizations.
- On daytime stations, sonabuoys are deployed and monitored by an acoustician, recording marine mammal vocalizations.
- On most winter (~Jan), all spring (~Apr), and some summer (~Jul) CalCOFIs, the CUFES egg pump is operated, drawing water from a depth of three meters. Seawater is pumped through an egg concentrator and the collected aggregate are examined; preliminary egg counts & larvae fish identification are performed, then the samples are preserved for further analysis on-shore.
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