INTRODUCTION
The data
presented in this report were collected during cruises 0207* and 0211
of the California
Cooperative Oceanic Fisheries Investigations (CalCOFI) program aboard
the aboard
the RV New Horizon of Scripps
Institution of Oceanography,
STANDARD
PROCEDURES
CTD/Rosette
Cast Data
A Sea-Bird Electronics, Inc.,
Conductivity-Temperature-Depth
(CTD) instrument (Seabird 911, Serial number 1049) with a rosette was
deployed
at each station on these cruises.
The
rosette was equipped with 24 ten-liter plastic (PVC) bottles equipped
with
epoxy-coated springs and Viton O-rings.
Each
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. The sample spacing was
designed to
sample depth intervals as close as 10 meters around the sharp upper
thermocline
features such as the chlorophyll, oxygen, nitrite maxima and the
shallow
salinity minimum. Salinity,
oxygen and
nutrients were determined at sea for all depths sampled. Chlorophyll-a and phaeopigments were determined at
sea on samples from the top 200 meters, bottom depth permitting.
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 samples were collected from all
rosette bottles and analyzed at sea using a Guildline model 8410
Portasal
salinometer. Salinity
samples were drawn
into 200 ml Kimax high-alumina borosilicate bottles that were rinsed
three
times with sample prior to filling.
The
results were compared with the CTD salinity to verify that the rosette
bottle
did not mis-trip or leak. The
salinometer was standardized before and after each group of samples
with
standardized seawater. Periodic
checks
on the conductivity of the standardized seawater were made by
comparison with
IAPSO Standard Seawater batch P134.
Salinity values were calculated using the algorithms for
the Practical
Salinity Scale, 1978 (UNESCO, 1981a) and are reported to three decimal
places,
provided that accepted standards were met.
Dissolved oxygen samples were collected in
calibrated 100 ml iodine flasks, allowing at least 200% overflow. The dissolved oxygen
samples were analyzed at
sea by the Winkler method, as modified by Carpenter (1965), using the
equipment
and procedure outlined by
Nutrient samples were analyzed at sea by the Scripps Ocean Data Facility. for dissolved silicate, phosphate, nitrate and nitrite using procedures similar to those described in Gordon et al., 1993. Samples were collected in 45 ml high-density polypropylene screw-capped tubes which were rinsed three times prior to filling. Standardizations were done at the beginning and end of each group of samples with a set of mid-concentration range standards prepared fresh for each run. Samples not analyzed immediately after collection were refrigerated and run the
* The first two digits represent the
year and the
last digits the month of the cruise.
following day. Sets of six different concentration standards were analyzed periodically to determine the deviation from linearity as a function of concentration, primarily for the silicate and nitrate analyses. Final sample concentrations were corrected for deviations from linearity.
Samples for chlorophyll-a
and phaeopigments were collected in
calibrated 138 ml polyethylene bottles and filtered onto Whatman GF/F
filters. The
pigments were extracted in
cold 90% acetone (Venrick and Hayward, 1984) for a mimimum of 24 hours. Chlorophyll a and
pheopigment concentrations
were determined from fluorescence readings before and after
acidification with
a Turner Designs Fluorometer Model 10-AU-005-CE (Yentsch and Menzel,
1963;
Holm-Hansen et al., 1965).
Evaluation of the water sample data
involved comparisons with the CTD data, 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).
Precision estimates for routine analyses were
made on CalCOFI cruise 9003 and are reported in SIO Ref. 91-4.
Primary
Productivity Sampling
Primary productivity samples were taken
each day shortly before local apparent
Macrozooplankton
Net Tows
Macrozooplankton was sampled with a 71 cm
mouth diameter paired net (bongo net) equipped with 0.505mm 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). An Optical Plankton
Counter (OPC, Dave
Checkley, SIO) was routinely used in one side of the paired bongo net
frame. The purpose
of the OPC is to
obtain information on the vertical distributions of size categories of
zooplankton, using data from the counter, without affecting the ongoing
time
series of data obtained from the catches of the integrative bongo net.
Avifauna
Observations (Point Reys Bird
Observatory)
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 that are not presented in this report. These programs
include:
1)
Underway
Data. Continuous
near surface
measurements of temperature, salinity and in vivo
chlorophyll
fluorescence were recorded from seawater pumped through the
ship’s
uncontaminated seawater system. Water
was drawn from a depth of approximately 3 meters.
The data were logged in one-minute averages
using a Sea-Bird Electronics, Inc., SBE 45 MicroTSG Thermosalinograph
and a Wetlabs
Wetstar fluorometer.
2)
ADCP. Continuous profiles of
ocean currents and
acoustic backscatter between 20 and 500 meters deep were measured along
the
shiptrack from a hull-mounted 150 kHz Acoustic Doppler Current Profiler
(ADCP).
The ADCP data were averaged over 3-minute intervals. Sixty 8-meter
depth bins
were recorded. (T. Chereskin, SIO)
3) Taxon-specific pigments:
Water samples
were collected from a depth of 10 m for the analysis of taxon-specific
pigments
(chlorophylls and carotenoids) by high-pressure liquid chromatography
(R.
Goericke, SIO).
4)
Trace metals. Pole sampling
was performed at 28 stations to obtain surface seawater for iron
analysis
(dissolved and total iron). Iron addition incubations were also
performed at 6
stations to assay for iron stress in the phytoplankton community.
Incubations
were maintained for up to 4 days in an on-deck flow-through incubator
and
sampled periodically for chlorophyll and nutrient concentrations (K.
Barbeau,
SIO).
TABULATED
DATA
CTD/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 profile. 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 are reported for most daylight stations.
Data values from discreet sampled CTD rosette were interpolated and are 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, 1981b). 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 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
that are 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 are reported
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.
FOOTNOTES
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 shipboard 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.