15 July to 26
August 2002
Nome, Alaska to
Nome, Alaska
CTD
casts were performed with a rosette system consisting of a 12-place rosette
frame with 30 liter Niskin-type
bottles equipped with internal plastic coated springs and a 24-place
SBE-32 Carousel pylon. Underwater
electronic components consisted of a
·
Sea-Bird
Electronics, Inc. (SBE) 911plus CTD,
·
WetLabs
C-Star transmissometer with a 25cm pathlength and 660nm wavelength,
·
Biospherical
Instruments, Inc. Photosynthetically Active Radiation (PAR) sensor,
·
Chelsea
MkIII Aquatracka fluorometer, and
·
Simrad,
5 volt - 500 meters altimeter.
Additionally,
a Dr. Haardt fluorometer designed to detect colored organic matter (CDOM), and
a Secchi disk were mounted on the CTD
package. The CTD, transmissometer and fluorometers were mounted horizontally
along the bottom of the rosette frame. The PAR sensor was located at the top of
the rosette. All sensors except the Secchi disk were interfaced with the CTD
system. This instrument package provided pressure, dual temperature and dual
conductivity channels as well as light transmissivity and fluorometric signals
at a sample rate of 24 scans per second.
The
rosette system was suspended from a standard UNOLS 3 conductor 0.322”
electromechanical cable.
The CTD
used was serial number 09P12613-0474 and the sensor’s serial numbers are listed
in Table 1.
TABLE 1. Instrument/Sensor Serial Numbers
|
Primary Temperature |
Primary Conductivity |
Secondary Temperature |
Secondary Conductivity |
Pressure |
Transmissometer |
|
SBE 3plus |
SBE 4C |
SBE 3plus |
SBE 4C |
401K-105 |
C-Star |
|
03-2324 |
04-2112 |
03-2166 |
04-23193 |
69008 |
CST-479DR |
|
Oxygen |
Fluorometer |
PAR |
|
SBE 43 |
Aqua 3 |
QSP-2300 |
|
0060 |
88191 |
4644 |
The
distance of the mid-points of the 30 L Niskin bottles from the bottom-mounted
sensors was ~1m . The PAR sensor was ~
0.6 m above the mid-point of the Niskin bottles, and the Secchi disk which is
mounted on a rod was ~ 0.9 m above the mid-point of the 30 L Niskin bottles.
The distance between the PAR sensor and the bottom mounted sensors was ~1.7
m. The 30 Liter Niskin bottles are ~1.0
m long.
Most of
the 30 liter Niskin-type bottles were manufactured by General Oceanics, but some were Ocean Test Equipment
bottles that had their external springs replaced with the same internal springs
used in the General Oceanics bottles. Bottle 7 was replaced after station 010
cast 01 and again after station 24 cast 4.
Bottle 4 was replaced after station 14 cast 2. To minimize toxicity the
bottles were equipped with silicone O-rings. At times the plastic coating on the springs broke down and some
rust was apparent. To minimize the occurrence of rust, the springs were
inspected before the cruise and, as feasible during the cruise. During the mid-cruise
servicing of the CTD/rosette system that occurred following station 024 cast
04, all springs were inspected and some were re-coated with plastic
CTD and Bottle
Data Distribution
The CTD and bottle data can be
obtained through the JOSS web-site, www.JOSS.ucar.edu/sbi. The data are reported
using the WHP-Exchange format. In addition, the format can be obtained through
the WOCE Hydrographic Program web-site, www.WHPO.ucsd.edu. Ascii files for each
station were created with comments recorded on the CTD Station Logs during data
acquisition. These ascii files include data processing comments noting any
problems, the resolution, and footnoting that may have occurred. A separate ascii file was also created with
the comments from the Sample Log Sheets that include problems with the Niskin
bottles that could compromise the samples. Comments arising from inspection and checking of the data are also
included in the ascii file. These comment files are also in the JOSS database.
Pre-cruise
laboratory calibrations of CTD pressure, temperature and conductivity sensors
were used to generate coefficients for the calculation of these parameters from
their respective sensor frequencies. The conductivity calibrations were
performed at Sea-Bird Electronics, Inc. in Bellevue, Washington. Calibration of the pressure and temperature
sensors were performed by Shipboard Technical Support/Oceanographic Data
Facility (STS/ODF) personnel. These laboratory temperature calibrations were
referenced to the International Temperature Scale of 1990 (ITS-90).
The CTD
911plus was operated generally as suggested in the Sea-Bird CTD Operating and
Repair Manual, which contains a description of the system, its operation and
functions (Sea-Bird Electronics, Inc., 2002). One difference from Sea-Bird’s
operation is that data acquisition was started on deck. This procedure allows a
check of the pressure offset and an unblocked reading of the transmissometer.
The Seasoft acquisition program as described in the CTD Data Acquisition
Software Manual (Sea-Bird Electronics, Inc., 2001) provided
a real-time graphical display of selected parameters adequate to monitor CTD
performance and information for the selection of bottle-tripping depths. Raw
data from the CTD were archived on the PC’s hard disk at the full 24 Hz
sampling rate.
A CTD Station Sheet form was filled
in for each deployment, providing a record of times, positions, bottom depth,
bottle sampling depths, and every attempt to trip a bottle, as well as any
pertinent comments. When the equipment and personnel were ready, data
acquisition was started. The CTD
operator pressed a control key (flag), which appends a summary line into one of
the two files created for “inventory” files.
These files contain a summary of the time, ship’s position, and current
scan number each time the control key is pressed. They are used as a reference to mark important events during the
cast, such as on deck pressure, when the lowering was initiated, when the
package was at the bottom, when bottles were tripped and the on-deck pressure
with ending position. After the initial
flag, the rosette/CTD system was lowered into the water and held at or near the
surface for 3-5 minutes to permit activation of the CTD pumps and equilibration
of the sensors. Then, the operator
again created a flag and simultaneously directed the winch operator to begin
lowering. The
operator created a flag at the deepest point of the cast. Bottom depths were
calculated by combining the distance above bottom, reported by the altimeter,
and the maximum depth of the CTD package when bottom altimeter readings were
available. If there was no altimeter
reading, then the bottom depth is reported from the ship’s Bathy 2000 or
Knudsen model 320B/R depth recorder.
These data, corrected for the draft of the transducer, were logged in
uncorrected meters (assuming a sound velocity of 1500 m/sec). If the altimeter
and depth recorder data were unavailable, the final resort was to use depth
data from the SeaBeam system (corrected sound velocities).
The depth of each bottle trip was written on the station log and
flagged in the data file. The
performance of all sensors was monitored during the cast. After the rosette recovery, the operator
created a final flag denoting the end of the cast. Any faulty equipment or
exceptionally noisy data were noted on the log sheet.
CTD
values determined on deck before and after each cast were compared to determine
a pressure offset correction. The comparison suggested that no pressure offset
was necessary.
The primary temperature sensor was
calibrated just before the expedition.
The dual temperature sensors were monitored during the expedition and
exhibited good agreement. It appears
that no additional corrections need to be applied. A post-cruise calibration
will be performed.
Corrected CTD pressure and temperature values were used
with bottle salinities to back-calculate bottle conductivities. Comparison of
these bottle values with the CTD primary conductivity values indicated no
additional offset needed to be applied to the data
A WetLab
calibrated Transmissometer was utilized throughout the cruise. An on deck calibration check was performed
and even though there was little degradation from the last calibration the new
coefficients were applied to the data set.
The CTD
oxygen data are only intended for qualitative use. Similarly, the fluorometric and PAR data are not calibrated.
CTD
Data Processing
Sea-Bird
Seasoft CTD processing software was employed. The processing programs are
outlined below. A more complete
description may be found in the Sea-Bird Software Manual which is available
from the Sea-Bird website (www.seabird.com).
The
sequence of programs that were run in processing CTD data from this cruise are
as follows:
·
DATCNV - Converts data from raw
frequencies and voltages to corrected engineering units
·
WILDEDIT - Eliminates
large spikes
·
CELLTM - Applies
conductivity cell thermal mass correction
·
FILTER – A
low pass filter to smooth pressure for LOOPEDIT
·
LOOPEDIT - Marks
scans where velocity is less than selected value to avoid pressure reversals
from ship roll, or during bottle flushing.
·
DERIVE - Computes
calculated parameters
·
BINAVG - Average
data into desired pressure bins
The
quality control steps included:
·
Sensor
verification After
the CTD was set up and sensor serial numbers and sensor location was entered
into the computer, another check was made to verify that there were no
tabulation errors.
·
Seasoft
Configuration File
was reviewed to verify that individual sensors were represented correctly, with
the correct coefficients.
·
Temperature was verified by comparing primary
and secondary sensor data.
·
Conductivity was checked by comparison of the
two sensors with each other and with bottle salinity samples.
·
Position
Check A chart
of the ship’s track was produced and reviewed for any serious problems. The positions were acquired from the ship’s
Trimble P-code navigation system.
·
Visual
Check Plots of
each usable cast were produced and reviewed for any noise and spikes that may
have been missed by the processing programs.
The density profile was checked for inversions that might have been produced by sensor noise or response mismatches.
·
Additional
Sea-Bird programs were run on all or some stations to maximize the data
quality.
·
WFILTER - Provides a median filter for
data smoothing of .CNV files
WFILTER was employed on selected stations where there were spikes in the data, specifically in the transmissometer data. This program was run after WILDEDIT
The
winch grounding system was periodically cleaned to reduce modulo errors, which
were not a significant problem during this leg (HLY0203). During the previous leg (HLY0201) there were
several modulo word errors at the beginning of the expedition. A check of all
connections and cables was performed and it was found that a shielding around
the winch motor eliminated the spiking and most of the noise in the CTD signal.
The CTD
down trace is reported unless there was a problem then the up trace is
reported. A notation was made in the comments file if this was necessary.
WHP
water sample quality flags were assigned to the CTDTMP (CTD temperature) and
CTDSAL (CTD salinity) parameters as follows:
2
Acceptable
measurement.
3
Questionable
measurement. The data did not fit the bottle data, or there was a CTD
conductivity calibration shift during the up-cast.
4
Bad
measurement. The CTD up-cast data were determined to be unusable for
calculating a salinity.
7
Despiked.
The CTD data have been filtered to eliminate a spike or offset.
WHP
water sample quality flags were assigned to the CTDOXY (CTD O2)
parameter as follows:
1
Not
calibrated. Data are uncalibrated.
2
Acceptable
measurement.
3
Questionable
measurement.
4
Bad
measurement. The CTD data were determined to be unusable for calculating a
dissolved oxygen concentration.
5
Not
reported. The CTD data could not be reported, typically when CTD salinity is
coded 3 or 4.
7
Despiked.
The CTD data have been filtered to eliminate a spike or offset.
9
Not
sampled. No operational sensor was present on this cast. Either the sensor
cover was left on or the depth rating necessitated removal
Fine
structure including minor density inversions that may appear in the upper ~ 10
m of the profiles is most likely caused by ship discharges/turbulence. A comparison cast made from a small boat at
station 14 is included in the data on the JOSS web site. These data revealed generally similar
profiles, but minor density inversions occurred in the shipboard profile and were
absent in the profile taken from the small boat. To minimize the ship effect,
engine cooling water discharges were restricted to the port side of the Healy
starting with station 002 during the previous leg (HLY0201) and continuing on
this leg. At about this time, a “yo yo”
procedure was adopted to induce bottle
flushing whenever waves and ship motion were weak. This procedure was employed for all bottle trips under quiescent
conditions except for productivity casts, and for some thin low salinity surface
lenses. In the latter cases, the CTD
was raised slowly so as not to disturb the thin low-salinity surface layers
with the CTD wake, and the soak time was relied on to flush the bottle. Even
though this procedure, may not have adequately flushed the surface bottle, it
was sufficient to reveal some large salinity differences in the ~ 1m depth
interval separating the CTD sensor from the bottle mid-point. These situations occurred in melting ice
under low winds and waves, and it is suspected that the water may have been
stratified even within the surface Niskin bottle. Regardless of the procedure
employed, the CTD operators were instructed to wait for at least 1 minute
(typically > 1.5 minutes) before tripping the bottle.
All salinity, nutrient and dissolved oxygen data collected by the service team have gone through several stages of editing and are not likely to change significantly. The chlorophyll observations reported are, however, preliminary and may undergo significant post-cruise editing.
There
were six generic types of casts performed with differing sampling
protocols. Generally speaking, the
sampling during these casts were as follows, but there is some cast-to-cast
variation.
·
Hydrographic
o
Oxygen,
o
Total
CO2,
o
Total
Alkalinity,
o
Nutrients
o
Chlorophyll
o
Salinity
o
O18/O16
o
Dissolved
Organic Carbon
o
Dissolved
Inorganic Carbon
o
Particulate
Organic Matter
o
Benthic
o
Stable
Isotopes
o
Radioisotopes
·
Productivity
o
Oxygen
and/or Oxygen Respiration
o
Productivity
o
Nutrients
o
Chlorophyll
o
HPLC
o
Bacteria
o
Micro
Zooplankton
o
Bio-Optics
·
Bio-Markers
o
Dissolved
Organic Matter
o
Lignin
·
Radium
o
Nutrients
o
Radium
·
Zooplankton
o
Nutrients
The
correspondence between individual sample containers and the rosette bottle from
which the sample was drawn was recorded on the sample log for the cast. This
log also included any comments or anomalous conditions noted about the rosette
and bottles.
Normal
sampling practice included opening the drain valve before the air vent on the
bottle, to check for air leaks. This observation together with other diagnostic
comments (e.g., "lanyard caught in lid", "valve left open")
that might later prove useful in determining sample integrity were routinely
noted on the sample log. Drawing oxygen samples also involved taking the sample
draw temperature from the bottle.
After
the samples were drawn and analyzed, the next stage of processing involved
merging the different data streams into a common file. The rosette cast and
bottle numbers were the primary identification for all ODF-analyzed samples
taken from the bottle, and were used to merge the analytical results with the
CTD data associated with the bottle.
Diagnostic
comments from the sample log, and notes from analysts and/or bottle data
processors were entered into a computer file associated with each station (the
"quality" file) as part of the quality control procedure. Sample data
from bottles suspected of leaking were checked to see if the properties were
consistent with the profile for the cast, with adjacent stations, and, where
applicable, with the CTD data. Direct inspection of the tabular data, property-property
plots and vertical sections were all employed to check the data. Revisions were
made whenever there was an objective reason to delete, annotate or re-calculate
a datum. WHP water sample codes were selected to indicate the reliability of
the individual parameters affected by the comments. WHP bottle codes were
assigned where evidence showed the entire bottle was affected, as in the case
of a leak, or a bottle trip at other than the intended depth.
WHP water
bottle quality codes were assigned as defined in the WOCE Operations Manual
[Joyce] with the following additional interpretations:
2
No
problems noted.
3
Leaking. An air leak large enough to produce an
observable effect on a sample is identified by a code of 3 on the bottle and a
code of 4 on the oxygen. (Small air
leaks may have no observable effect, or may only affect gas samples.)
4
Did
not trip correctly. Bottles tripped
at other than the intended depth were assigned a code of 4. There may be no problems with the associated
water sample data.
5
Not
reported. No water sample data
reported. This is a representative
level derived from the CTD data for reporting purposes. The sample number should be in the range of
80-99.
9
The
samples were not drawn from this bottle.
WHP
water sample quality flags were assigned using the following criteria:
1
The
sample for this measurement was drawn from the water bottle, but the results of
the analysis were not (yet) received.
2
Acceptable
measurement.
3
Questionable
measurement. The data did not fit the station profile or adjacent station
comparisons (or possibly CTD data comparisons). No notes from the analyst
indicated a problem. The data could be acceptable, but are open to
interpretation.
4
Bad
measurement. The data did not fit the station profile, adjacent stations or
CTD data. There were analytical notes indicating a problem, but data values
were reported. Sampling and analytical errors were also coded as 4.
5
Not
reported. There should always be a reason associated with a code of 5,
usually that the sample was lost, contaminated or rendered unusable.
9
The
sample for this measurement was not drawn.
Not all
of the quality codes are necessarily used on this data set.
All
pressures and temperatures for the bottle data tabulations were obtained by
averaging CTD data for a brief interval at the time the bottle was closed and
then applying the appropriate calibration data.
The
temperatures are reported using the International Temperature Scale of 1990.
Salinity samples were drawn into
200 ml high alumina borosilicate bottles, which were rinsed three times with
sample prior to filling. The bottles were sealed with custom-made plastic
insert thimbles and Nalgene screw caps This container provides very low
container dissolution and sample evaporation.
A Guildline Autosal 8400A #57-526,
standardized with IAPSO Standard Seawater (SSW) batch P-140, was used to
measure the salinities. Prior to the analyses, the samples were stored to
permit equilibration to laboratory temperature, usually 8-20 hours. The salinometer was modified by ODF and
contained an interface for computer-aided measurement. The salinometer was
standardized with a fresh vial of standard seawater at the beginning and end of
the run. The SSW vial at the end of the
run was used as an unknown to check for drift. The salinometer cell was flushed
until two successive readings met software criteria for consistency; these were
then averaged for a final result. The estimated accuracy of bottle salinities
run at sea is usually better than 0.002 PSU relative to the particular standard
seawater batch used.
The temperature stability in the
salinometer laboratory was fair, sometimes varying as much as 3.5ºC during a
run of samples. The laboratory
temperature was generally 1-2ºC lower than the Autosal bath temperature.
Dissolved oxygen analyses were
performed with an ODF-designed automated oxygen titrator using photometric
end-point detection based on the absorption of 365nm wavelength ultra-violet
light. The titration of the samples and the data logging were controlled by PC
software. Thiosulfate was dispensed by a Dosimat 665 buret driver fitted with a
1.0 ml buret. The ODF method used a whole-bottle modified-Winkler titration
following the technique of Carpenter (1965) with modifications by Culberson
(1991), but with higher concentrations of potassium iodate standard
(approximately 0.012N) and thiosulfate solution (55 g/l). Standard KIO3
solutions prepared ashore were run at the beginning of each run. Reagent and
distilled water blanks were determined, to account for presence of oxidizing or
reducing materials.
Samples
were collected for dissolved oxygen analyses soon after the rosette was brought
on board. Using a Tygon drawing tube, nominal 125ml volume-calibrated iodine
flasks were rinsed, then filled and allowed to overflow for at least 3 flask
volumes. The sample draw temperature was measured with a small platinum
resistance thermometer embedded in the drawing tube. Reagents were added to fix
the oxygen before stoppering. The flasks were shaken twice to assure thorough
dispersion of the precipitate, once immediately after drawing, and then again
after about 20 minutes. The samples
were usually analyzed within a few hours of collection.
Thiosulfate normalities were calculated from each standardization and corrected to 20ºC. The 20ºC normalities and the blanks were plotted versus time and were reviewed for possible problems. New thiosulfate normalities were recalculated as a linear function of time, if warranted. The oxygen data were recalculated using the smoothed normality and an averaged reagent blank. Oxygens were converted from milliliters per liter to micromoles per kilogram using the sampling temperature.
Oxygen
flask volumes were determined gravimetrically with degassed deionized water to
determine flask volumes at ODF’s chemistry laboratory. This is done once before
using flasks for the first time and periodically thereafter when a suspect
bottle volume is detected. The volumetric flasks used in preparing standards
were volume-calibrated by the same method, as was the 10 ml Dosimat buret used
to dispense standard iodate solution.
Potassium
iodate was obtained from Johnson Matthey Chemical Co. and was reported by the
supplier to be >99.4% pure.
Nutrient
analyses (phosphate, silicate, nitrate+nitrite, urea, ammonium, and nitrite)
were performed on an ODF-modified 6-channel Technicon AutoAnalyzer II,
generally within a few hours after sample collection. Occasionally samples were refrigerated for longer periods and the
data are annotated if it was felt that the storage time had a significant
effect. Frozen samples left for us to
analyze from a previous group were also analyzed during this leg. The analog
outputs from each of the six channels were digitized and logged automatically
by computer (PC) at 2-second intervals.
A suite of frozen nutrient samples from the Bering Sea (~300) left for
us to analyze by participants in HLY0202 (the cruise that separated the two
Process cruises, HLY0201 and HLY0203) was also analyzed. Many of the frozen
samples had extremely high silicate concentrations and only those values
of about 50 micromolar or less should
be considered reliable. This is because
of the problem of silicate polymerization during freezing and because the
silicate method employed was optimized for waters with silicate concentrations
between 0 and 90 micromolar. The
samples were thawed in a warm tap water bath and analyzed as soon as possible in
order to obtain the best possible data on the nutrients other than
silicate. For a discussion of the
effects of freezing on silicate concentrations see Macdonald et al.
(1986).
Silicate
was analyzed using the technique of Armstrong et al., (Armstrong, 1967).
The sample was passed through a 15mm flowcell and the absorbance measured at
660nm.
A
modification of the Armstrong et al. (Armstrong 1967) procedure was used
for the analysis of nitrate and nitrite. For the nitrate plus nitrite analysis,
the seawater sample was passed through a cadmium reduction column where nitrate
was quantitatively reduced to nitrite. The stream was then passed through a
15mm flowcell and the absorbance measured at 540nm. The same technique was employed for nitrite analysis, except the
cadmium column was bypassed, and a 50mm flowcell was used for measurement. Periodic checks of the column efficiency
were made by running alternate equal concentrations of NO2 and NO3 through the
NO3 channel to ensure that column efficiencies were high (> 95%). Nitrite
concentrations were subtracted from the nitrate+nitrite values to obtain
nitrate concentrations.
Phosphate
was analyzed using a modification of the Bernhardt and Wilhelms [ Bernhardt
1967.] technique. The reaction product was heated to ~55ºC to enhance color
development, then passed through a 50mm flowcell and the absorbance measured at
820m.
Ammonium
was determined by the Berthelot reaction (Patton and Crouch 1977) in which
sodium hypochlorite and phenol react with ammonium ion to produce indophenol
blue, a blue compound, with an absorption maximum at 637nm. The solution was heated to 55°C and passed
through a 50mm flowcell at 640nm.
Urea was
analyzed via a modification of the method of Rahmatullah and Boyde (1980),
which is based on the classic diacetyl monoxime method. A solution of diacetyl monoxime,
thiosemicarbizide and acetone is followed by the addition of ferric chloride,
which acts as a catalyst. The resultant
solution is heated to 90°C and passed through a 50mm flowcell. The absorbance
is measured at 520nm.
Nutrient samples were drawn into 45 ml polypropylene, screw-capped “oak-ridge type” centrifuge tubes. The tubes were cleaned with 10% HCl and rinsed with sample three times before filling. Standardizations were performed at the beginning and end of each group of analyses (typically 6-24 samples) with an intermediate concentration mixed nutrient standard prepared prior to each run from a secondary standard in a low-nutrient seawater matrix. The secondary standards were prepared aboard ship by dilution from primary standard solutions. Dry standards were pre-weighed at the laboratory at ODF, and transported to the vessel for dilution to the primary standard. Sets of 6-7 different standard concentrations covering the range of sample concentrations were analyzed periodically to determine the deviation from linearity, if any, as a function of concentration for each nutrient analysis. A correction for non-linearity was applied to the final nutrient concentrations when necessary.
After each
group of samples was analyzed, the raw data file was processed to produce
another file of response factors, baseline values, and absorbances.
Computer-produced absorbance readings were checked for accuracy against values
taken from a strip chart recording. A stable deep seawater check sample was run
frequently as a substandard check.
Nutrients,
when reported in micromoles per kilogram, were converted from micromoles per
liter by dividing by sample density calculated at 1 atm pressure (0 db), in
situ salinity, and an assumed laboratory temperature of 25ºC.
Na2SiF6,
the silicate primary standard, was obtained from Johnson Matthey Company and
Fisher Scientific and was reported by the suppliers to be >98% pure. Primary
standards for nitrate (KNO3), nitrite (NaNO2), and phosphate (KH2PO4)
were obtained from Johnson Matthey Chemical Company., and the supplier reported
purities of 99.999%, 97%, and 99.999%, respectively. Ammonia, (NH4(SO4)2), and
Urea primary standards were obtained from Fisher Scientific and reported to be
>99% pure. In addition, during the HLY0201 leg, L. A. Codispoti supplied
independent comparisons standards for all nutrients. All standard
intercomparisons, produced agreement well within the precision of the employed
methods.
Armstrong,
F. A. J., Stearns, C. R., and Strickland, D. H., “The measurement of upwelling
and subsequent biological processes by means of the Technicon Autoanalyzer and
associated equipment,” Deep-Sea Research, 14, pp. 381-389, (1967).
Bernhardt,
Wilhelms A., “The continuous determination of low level iron, soluble phosphate
and total phosphate with the AutoAnalyzer”, Technicon Symposia, I, pp. 385-389 (1967).
Carpenter,
J. H., “The Chesapeake Bay Institute technique for the Winkler dissolved oxygen
method,” Limnology and Oceanography, 10, pp. 141-143 (1965).
Culberson,
C. H., Knapp, G., Stalcup, M., Williams, R.T., and Zemlyak, F., “A comparison
of methods for the determination of dissolved oxygen in seawater,” Report WHPO
91-2, WOCE Hydrographic Programme Office (Aug 1991).
Gordon,
L.I., Jennings, J.C., Ross, A.A. and J.M. Krest, “A Suggested Protocol for
Continuous Flow Automated Analysis of Seawater Nutrients in the WOCE
Hydrographic Program and the Joint Global Ocean Fluxes Study”. 1993. WOCE
Hydrographic Programs Office, Methods Manual WHPO 91-1.
Intergovernmental
Oceanographic Commission, Scientific Committee on Oceanic Research Manual and
Guides 29 Protocols for the Joint Global Ocean Flux Study (JGOFS) Core
Measurements. UNESCO, 170pp., (1994).
Joyce,
T. ed., and Corry, C. ed., “Requirements for WOCE Hydrographic Programme Data
Reporting,” Report WHPO 90-1, WOCE Report No. 67/91 3.1, pp. 52-55, WOCE
Hydrographic Programme Office, Woods Hole, MA, USA (May 1994, Rev. 2),
UNPUBLISHED MANUSCRIPT
Macdonald,
R.W., F. A. McLaughlin and C.S. Wong,
“The storage of reactive silicate samples by freezing,” Limnology and
Oceanography, 31, pp. 1139-1142 (1986).
Patton,
C.J. and Crouch, S.R., “Spectrophotometric and kinetics investigation of the
Berthelot reaction for the determination of ammonia,” Analytical Chemistry,
49(3), pp.464-469 (1977).
Rahmatullah,
Mohammed, and Boyde, T.R.C, “Improvements in the determination of urea using
diacetyl monoxime; methods with and without deproteinisation,” Clinica
Chimica Acta, 107, pp.3-9 1980.
Sea-Bird
Electronics, Inc, CTD Data Acquisition Software Manual, March 2001
Sea-Bird
Electronics, Inc., CTD Operating and Repair Manual, February 2002