The data in this report were collected during cruises
9507* and 9510 of the California Cooperative Oceanic Fisheries
Investigations (CalCOFI) program aboard the NOAA ship RV David
Starr Jordan and RV New Horizon of Scripps Institution
of Oceanography, University of California, San Diego. The CalCOFI
program was organized in the late 1940's to study the causes of
variations in population size of fishes of importance to the State
of California. It is carried out by NOAA's National Marine Fisheries
Service Southwest Fisheries Science Center, the California Department
of Fish and Game, and the Marine Life Research Group (MLRG) at
Scripps Institution of Oceanography (SIO). MLRG contributes to
this program by investigations of the physical, chemical and biological
structure of the California Current. Data from CalCOFI cruises
9507 and 9510 were collected and processed by personnel of the
Marine Life Research Group and the Southwest Fisheries Science
Center. Volunteers and other SIO staff members also assisted in
the collection of data and chemical analyses at sea.
Rosette Cast Data
At each station on cruises 9507 and 9510 a Sea-Bird
Electronics, Inc., Conductivity-Temperature-Depth (CTD) instrument
was deployed with a 24-place General Oceanics rosette. The rosette
was equipped with 24 ten-liter plastic (PVC) bottles. The CTD/rosette
cast usually sampled 20 depths to a maximum sampling depth of
525 meters, bottom depth permitting. Occasional stations have
multiple bottles tripped at the same depth to provide more water
for ancillary programs. Pressures and temperatures assigned to
the water sample data were derived from the CTD signals recorded
just prior to the bottle trip. Pressures have been converted to
depths by the Saunders (1981) pressure-to-depth conversion technique.
CTD temperatures reported with the bottle data have been rounded
to the nearest hundredth of a degree Celsius. Salinity, oxygen
and nutrients were determined at sea for all depths sampled. Chlorophyll-a
and phaeopigments were determined at sea within the top 200 meters,
bottom depth permitting.
Salinity samples were collected from all rosette
bottles and analyzed at sea using a Guildline model 8410 Portasal
salinometer. The results were compared with the CTD salinity in
order to verify that the rosette bottle did not mis-trip or leak.
The salinometer was standardized before and after each group of
samples with substandard seawater. Periodic checks on the conductivity
of the substandard were made by comparison with IAPSO Standard
Seawater batch P127. Salinity values have been calculated from
the algorithms for the Practical Salinity Scale, 1978 (UNESCO,
1981a) and were reported to three decimal places, provided that
accepted standards were met. If only one determination per sample
was obtained, or there was doubt concerning the accuracy of the
analytical results, the salinities were reported to two decimal
places.
Dissolved oxygen was determined by the Winkler method,
as modified by Carpenter (1965), using the equipment and procedure
outlined by Anderson (1971). Percent oxygen saturation was calculated
from the equations of Weiss (1970).
Silicate, phosphate, nitrate and nitrite nutrients
were determined at sea using an automated analyzer. The procedures
used are similar to those described in Atlas et al. (1971).
Samples for chlorophyll-a and phaeopigments
were filtered onto Whatman GF/F filters. The pigments were extracted
with a cold extraction technique in 90% acetone (Venrick and Hayward,
1984), and the fluorescence determined before and after acidification
with a Turner Designs fluorometer (Yentsch and Menzel, 1963; Holm-Hansen
et al. 1965).
Evaluation of the data involved comparisons with
the CTD cast profiles, adjacent stations and consideration of
the variation of a property as a function of density or depth
and the relationships with other properties (Klein, 1973). Estimates
of precision of the standard techniques are given in SIO, 1991.
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* The first two digits represent the year and the
last digits the month of the cruise.
Primary Productivity Sampling
Primary productivity samples were taken each day
shortly before local apparent noon (LAN). Primary production was
estimated from 14C uptake
using a simulated in situ technique. Light penetration
was estimated from the Secchi depth (assuming that the 1% light
level is three times the Secchi depth). The depths with ambient
light intensities corresponding to light levels simulated by the
on-deck incubators were identified and sampled on the up rosette
cast. Occasionally an extra bottle or two were tripped in addition
to the usual 20 levels sampled in the combined rosette-productivity
cast in order to maintain the normal sampling depth resolution.
The ten-liter bottles were equipped with epoxy-coated springs
and Viton O-rings. Triplicate samples (two light and one dark
control) were drawn from each productivity sample depth into 250
ml polycarbonate incubation bottles. Samples were inoculated with
10 µCi of 14C as
NaHCO3 (200 µl of
50 µCi/ml stock) prepared in a 0.3 g/liter solution of sodium
carbonate (Fitzwater et al. 1982). Samples were incubated
from LAN to civil twilight in seawater-cooled incubators with
neutral-density screens which simulate in situ light levels.
At the end of the incubation, the samples were filtered onto Millipore
HA filters and placed in scintillation vials. One half ml of 10%
HCl was added to each sample. The sample was then allowed to sit,
without a cap, at room temperature for 12 hours (after Lean and
Burnison, 1979). Following this, 10 ml of scintillation fluor
were added to each sample and the samples were returned to SIO
where the radioactivity was determined with a scintillation counter.
Salinity, oxygen, nutrients, chlorophyll-a and phaeopigments
were determined from all rosette productivity bottles.
Macrozooplankton Net Tows
Macrozooplankton was sampled with a 71 cm mouth diameter
paired net (bongo net) equipped with 0.505 mm plankton mesh. Bottom
depth permitting, the nets were towed obliquely from 210 meters
to the surface. The tow time for a standard tow was 21.5 minutes.
Volumes filtered were determined from flowmeter readings and the
mouth area of the net. Only one sample of each pair was retained
and preserved. The biomass, as wet displacement volume, after
removal of large (>5 ml) organisms, was determined in the laboratory
ashore. These procedures are summarized in greater detail in Kramer
et al. (1972).
Avifauna Observations
Sea birds were counted within a 300 meter wide strip
off to one side of the ship. Counts were made while underway between
stations during periods of daylight. These counts were summed
over 20 nautical mile (nm) intervals, or the distance between
consecutive stations, whichever was less. Included at the end
of this report are individual maps of the most numerous bird species
(individuals/nm).
Ancillary Programs
Several ancillary programs produced data on these cruises which are not presented in this report. These programs include:
1) Underway Data. Continuous near surface measurements of temperature, salinity and chlorophyll fluorescence were made from water pumped through the ship, and the data are logged at one minute intervals.
2) ADCP. Acoustic Doppler Current Profiler data were recorded continuously along the ship's cruise track.
3) Bio-optics. Bio-optical profiles were measured almost daily using a variety of sensors. In addition the bio-optics program included cyanobacteria microscopic counts by epifluorescence, phycoerythrin pigment concentration determined by fluorescence spectroscopy, soluble and particulate absorption and fluorescence spectra, and experiments on the photo-oxidative loss of soluble and particulate absorption and fluorescence spectra.
4) Pigment studies. These included measurement of 14C incorporation into pigments in incubated samples, phytoplankton pigment analyses of euphotic zone samples using high performance liquid chromatography, phytoplankton fluorescence measurements before and after DCMU addition, and nutrient enrichment experiments to assess changes in phytoplankton fluorescence, source-specific nitrogen uptake rates, and phytoplankton population changes as indicated by pigment concentrations.
5) Benthic sampling. On cruise 9510 bottom
samples were taken at four sites. Samples were preserved for subsequent
analysis of benthic foraminifera, organic carbon analysis, and
other faunal and geochemical analyses.
TABULATED DATA
Rosette Cast Data
The time reported is the Coordinated Universal Time (UTC) of the first rosette bottle trip on the up cast. The rosette bottles tripped on the up cast are reported as cast 2, where cast 1 is considered to be the down CTD cast. The
sample number reported is the cast number followed
by a two digit rosette bottle number. Bottom depths, determined
acoustically, have been corrected using British Admiralty Tables
(Carter, 1980) and are reported in meters. Weather conditions
have been coded using WMO code 4501. Secchi depths and Forel water
color scales are also reported for most daylight stations.
Observed data from individual CTD/rosette trip levels
are interpolated and reported for standard depths. Interpolated
or extrapolated standard level data are noted by the footnote
"ISL" printed after the depth. Multiple bottles tripped
at the same depth to provide water for ancillary programs are
not used in the calculation of standard depth data. Density-related
parameters have been calculated from the International Equation
of State of Seawater 1980 (UNESCO, 1981, b). Computed values of
potential temperature, sigma-theta, specific volume anomaly (SVA),
and dynamic height or geopotential anomaly are included with both
observed and interpolated standard depth levels.
On stations where primary productivity samples were
drawn from six of the rosette bottles, a footnote appears after
each productivity depth sampled. The corresponding primary productivity
data are reported in a separate section following the tabulated
rosette cast data.
Primary Productivity Data
In addition to the normal hydrographic data also
reported in the rosette cast data section, the tabulated data
include: the in situ light levels at which the samples
were collected, the uptake from each of the replicate light bottles,
uptake 1 and uptake 2, (which have been corrected for dark uptake
by subtracting the dark value), the mean of the two uptake values
and the dark uptake. The uptake values are totals for the incubation
period. Also shown are the times of LAN, civil twilight, and the
value of the mean uptake integrated from the surface to the deepest
sample, assuming the shallowest value continues to the surface
and that negative values (when dark uptake exceeds light uptake)
are zero. The uptake data have been presented to two significant
digits (values <1.00) or one decimal (values >1.00). Precision
of the higher production values may not warrant all of the digits
presented. Incubation time, LAN, and civil twilight are given
in local Pacific Standard Time (PST); to convert to UTC, add eight
hours to the PST time. Incubation light intensities are listed
in a footnote at the bottom of each page.
Macrozooplankton Data
Macrozooplankton biomass volumes are tabulated as
total biomass volume (cm3/1000m3
strained) and as the total volume minus the
volume of larger organisms under the heading "Small."
Tow times are given in local PST (+8) time.
In addition to footnotes, special notations are used
without footnotes because the meaning is always the same.
D: CTD salinity value listed in place of normal ship-board salinity analysis.
ISL: After a depth value indicates that this is an interpolated or extrapolated standard level.
U: Uncertain value. Values which are not used in interpolation because they seem to be in error without
apparent reason.