A. Cruise narrative
A.1. Highlights: Expedition; Chief Scientist; Ship; Ports of Call; Cruise dates
A.2. Cruise summary
A.3. Narrative
A.4. Interlaboratory comparisons of chemistry methods
A.5. List of principal investigators
A.6. Cruise participants
B. Description of measurement techniques and calibration
B.1. CTD (conductivity-temperature-depth): Carl Mattson (SIO/ODF)
B.2. Salinity analyses: Carl Mattson (SIO/ODF)
B.3. Oxygen water sample analyses: Carl Mattson and Ron Patrick
B.4. Nutrient analyses: Carl Mattson and Doug Masten (SIO/ODF)
B.5. Chlorofluorocarbon measurements: Mark Warner and DongHa Min (UW)
B.6. Alkalinity and pH: Dong-Jin Kang (SNU) and Pavel Tischenko (POI)
B.7. Noble Gas and Tritium Sampling: Clare Postlethwaite (SOC)
B.8. Oxygen Isotope Sampling: Clare Postlethwaite (SOC)
B.9. Other SNU sampling (helium, tritium, D-14, Del 18O, SF6): Dong-Jin Kang (SNU)
B.10. Underway pCO2 measurements: Dong-Jin Kang, Doshik Hahm (SNU)
B.10.a. pCO2 measurements.
B.10.b. Thermosalinograph measurements.
B.10.c. Underway chlorophyll sampling.
B.11. Acoustic doppler current profiling (ADCP): Lynne Talley (SIO)
B.11.a. Lowered ADCP.
B.11.b. Underway ADCP.
B.12. Meteorology: R/V Revelle (Talley; SIO)
B.13. Navigation: R/V Revelle (Talley; SIO)
B.14. Bathymetry: R/V Revelle (Talley; SIO)
B.15. Video Plankton Recorder (VPR): Carin Ashjian (WHOI)
B.16. Plankton net tows: Carin Ashjian and Cabell Davis (WHOI)
B.17. Bio-optical studies: Greg Mitchell (SIO)
C. Distribution of data and samples to groups other than originating
principal investigators
a. Expedition
b. Chief Scientist
c. Ship
d. Ports of Call
e. Cruise dates
a. Cruise track (Fig. A.1)
Digital pictures, courtesy of Andy Girard.
b. Station sampling
c. Underway sampling
towed VPR (Video Plankton Recorder), with planktonic taxonomic
type and abundance, temperature,
conductivity, fluorescence, light attenuation and PAR
yoyoing to 80 meters depth once or twice between CTD stations.
d. Floats and drifters
The R/V Revelle departed Pusan, Korea on June 24, 1999 at 1600 in good
weather and
returned on July 17.
This was the seventh leg of the Hahnaro (HNRO) expedition.
Generally calm to moderate seas throughout the cruise. Air temperature
was in the 16-22 C range. There was occasional rain.
Three separate sampling programs were aboard: CTD/rosette/chemistry,
bio-optics,
and VPR (Video Plankton Recorder).
The cruise leg covered the Korean and Japanese sectors of the Japan/East
Sea.
The purposes of the cruise leg were to map the water properties and
geostrophic
circulation
of the Japan/East Sea from top to bottom, the bio-optical properties,
and
the plankton distribution.
The water properties and circulation of the Russian sector were
measured in a companion cruise on the Khromov, following the Revelle
leg.
CTD/rosette station sampling was to the bottom at each of the 112
stations.
Most stations were separated by 10 to 30 nautical miles. The station
pattern covered most of the southern and eastern Japan/East Sea.
One station near Dok Do was abandoned because
the local Korean patrol was not aware of our clearance to work.
One extra station (113) to 800 m was made on the return to Pusan in
order
to test the CTD which will be the backup CTD on the Khromov. On most
stations, 24 samples were collected from top to bottom. Maximum bottle
spacing in the deep waers was 250 meters with some exceptions. Most
sampling in the upper waters was based on the many
features in the CTD salinity and oxygen and the transmissometer.
An altimeter on the CTD/rosette frame was used for the bottom approach
on most
stations. A pinger on the CTD/rosette frame was used for several
stations.
A lowered acoustic doppler current profiler was used on every station.
The VPR was towed between most station pairs except for the longer
steams between sections. On most days two separate casts for bio-optics
were made. At these stations, extra samples for bio-optical properties
were often collected from near-surface rosette bottles from the CTD
cast.
A plankton net tow was done at 15 stations.
Alkalinity and pH:
A comparison of alkalinity and pH methods between the Seoul National
University group under Kyung-Ryul Kim (Dong-Jin Kang aboard the
Revelle) and the Pacific Oceanological Institute group under Pavel
Tishchenko was carried out during the cruise. POI sampling for pH and
alkalinity was at every station. SNU sampling was at 15 stations for
comparison of methods. The results of the comparison are included in
section B.6.c.
CFC:
Samples for CFCs were collected in glass ampoules for analysis
at the UW laboratory and comparison with analyses carried out on the
Revelle. All CFC sampling on the Khromov will be using these glass
ampoules.
CTD fish numbers used:
The rosette consisted of:
CTD#3:
Bottles:
Thermometers:
Transmissometer:
Winches:
Station-Cast number assignments:
SALINOMETER TYPES SERIAL NUMBERS
WORMLEY standard water used:
Comments:
Autosals were configured for computer-aided measurement. The data
were
acquired on a PC.
#48-263 stations 1-113 24 deg bath temp
Oxygens were run on all stations using a Dosimat UV-endpoint detection
automatic titration system.
Comments:
Nutrients were measured on all stations using a Technicon AA-II CFA
system
with a PC based acquisition system. Nutrients measured - NO2, NO3, PO4,
SIO3.
Comments:
The system performed well with few problems. Data were reviewed by
analysts
and transferred to the processing computer for integration with
other water sample data.
epsilon1(I2-)/
epsilon2(HI-) = 2.222
epsilon2(I2-)/
epsilon2(HI-) = 0.133 All SNU data reported here are averaged
value of duplicate analysis. The average precision of duplicate analysis is
0.006 pH unit is one standard deviation. POI used potentiometric measurement
in a potential cell without liquid junction for pH measurements of
seawater, since it was reported
that unreproducibility and loss of accuracy of potentiometric pH
measurement are caused by liquid junction potential (Tishchenko and
Pavlova, 1999).
A. Cruise narrative
A.1. Highlights
HNRO7 (Expedition Hahnaro Leg 7)
Lynne D. Talley
Scripps Institution of Oceanography 0230
La Jolla, CA 92093-0230 USA
ltalley@ucsd.edu
R/V Revelle, Captain David Murline
Pusan, Korea
24 June 1999 - 17 July 1999
A.2. Cruise summary
List of events, from ship's
officers, with all station (CTD, optical, net tow) and VPR towing times.
CTD station locations and times
in WOCE Hydrographic Programme format.
113 CTD/24-bottle rosette stations; 112 stations included LADCP
(2156 bottles tripped)
Water sampling to the bottom for temperature, salinity, oxygen,
transmissometer,
nitrate, phosphate, silicate, nitrite, CFC's, pH,
alkalinity, C14, del18O, helium, tritium, argon, neon. Surface sampling
at
selected station locations for delta-C13, phytoplankton growth
rates and calcite. Average depth of cast: 2500 m.
37 Bio-optical casts
15 Net tows near the surface
pCO2
surface temperature and salinity
Seabeam center beam bathymetry
Knudsen echo sounder bathymetry
ADCP (Acoustic Doppler Current Profiling)
meteorology
2 Minimet surface drifters
2 Profiling ALACE floats ballasted to 800 meters
A.3. Narrative
A.4. Interlaboratory comparisons of chemistry methods
A.5. List of principal investigators
A.6. Cruise participants
Institution acronyms
B. Description of measurement techniques and calibration
B.1. CTD (conductivity-temperature-depth): Carl Mattson (SIO/ODF)
CTD data were recorded on IBM PC's.
Digital backups were made on CDROMS and Zip disks.
Analog backups were made on VCR cassettes.
NBIS Model MKIII ODF CTD#3 stations 1-8,113
NBIS Model MKIII ODF CTD#5 stations 9-112
NBIS MKIIIB CTD s/n 01-1095 (ODF ctd#3) sta 1-8, 113
Comments:
NBIS MKIIIB CTD s/n 01-1070 (ODF ctd#5) sta 9-112
Sensormedics Oxygen Sensor s/n 6-12-07 sta 1-108
Sensormedics Oxygen Sensor s/n 6-12-08 sta 109
Sensormedics Oxygen Sensor s/n 6-02-08 sta 110-113
FSI OTM s/n 1322 sta 113
STS 24 bottle rosette frame
24pl Seabird pylon model SBE32 s/n 3212613-0164
Seabird Temperature Sensor SBE35 s/n 3516590-0011
SIO made Bullister style 10 liter bottles
Benthos Pinger model 2216 s/n 1275
Simrad Altimeter model 807 s/n 0711090
STS Battery Pack for Altimeter
RDI LADCP CS-150KHZ s/n 1546
LADCP Battery Pack
Wetlabs Cstar 25cm transmissometer c/n CST-244DB
Wetlabs Cstar 25cm transmissometer c/n CST-245DB
Conductivity sensor failed during Sta 9 cast 1.
CTD#5:
Ctd#3 was replaced by CTD#5 prior to sta 9 cast 2.
FSI OTM #1322 was the second temp sensor on sta 113
The conductivity sensor drifted again on sta 113.
CTD #5 has dual sensors mounted on twin turrets -
two identical Temperature channels and two identical conductivity
channels.
CTD sensors soaked in distilled water between all casts.
Swapped sensor pair in config file starting sta 59.
PRT#2 and COND#2 were the most stable sensor pair so these were used in
onboard data processing operations for both CTD and bottle data
reports.
PRT#1 (after about sta92) was observed to jump about
0.0008 deg on casts greater that 3200M. It was usually
observed on the upcasts coming through about 3300M then
jumped back to overlap downcast trace when it
comes back up - around 3000M. Could be a digital
bit sticking in that channel (bit #5?).
Cond#1 sensor has a pressure effect on deep casts
and will require a pressure fit correction.
10L Bullister style, SIO manufactured.
Bottles serial numbered 1-24 corresponded to the pylon tripping
sequence 1-24 with the first bottle tripped being bottle #1.
Bottles serial numbered 1-24 were used on all casts.
The SBE35 Ref temp sensor data was recorded on all bottle trips.
CTD oxygen:
No DSRT's
Oxygen data interfaced with the CTD and incorporated into
the CTD data stream using a:
Sensormedics Oxygen Sensor s/n 6-12-07 sta 1-108
Sensormedics Oxygen Sensor s/n 6-12-08 sta 109
Sensormedics Oxygen Sensor s/n 6-02-08 sta 110-113
Wetlabs Cstar 25cm (Blue) Transmissometer c/n CST-244DB
Wetlabs Cstar 25cm (RED) Transmissometer c/n CST-245DB
Forward Markey CTD winch used on all casts
No wire or winch problems throughout the cruise.
Cast numbers were assigned between the CTD and the
Bio-Optical profiler depending on which was deployed first.
Station 9 was the only station that the CTD was deployed
on two casts.
B.2. Salinity analyses: Carl Mattson (SIO/ODF)
Guildline 8400A Autosal 55-503
Guildline 8400A Autosal 48-263
Batch P-134
203 vials used
2 bad vials
B.3. Oxygen water sample analyses: Carl Mattson and Ron Patrick
(SIO/ODF)
No major problems, hardly any problems.
The titrator employed a Brinkman Dosimat 665 automatic burette and
an
Ultraviolet detection system interfaced with a PC for data
acquisition
and control.
B.4. Nutrient analyses: Carl Mattson and Doug Masten (SIO/ODF)
Glass-electrode-Na+ |
Test (standard) solution |
H+-glass-electrode |
(A) |
The cell (A) was calibrated by T RIS-buffer (DelValls and Dickson, 1998) at 25 oC and pH is calculated by formula:
where E, mNa, and g Na are EMF, sodium ion molality and activity coefficient of sodium ion, respectively; subscript indices s, x denote standard and test solutions, respectively. Activity coefficients of sodium ion have been calculated by Pitzer method (Pitzer, 1992) and approximated by empirical formula below.
Properties of sodium ion as follows
(mNa)s = 0.44618
(g Na)s = 0.6412
where S is salinity; I is an ionic strength which calculated by equation
Shift of a standard EMF of the cell (A) was less then 0.5 mV/ per day. The precision of pH measurement by means of the cell (A) is about ± 0.004 pH unit.
Total Alkalinity (TA)
SNU used potentiometric titration measuring EMF in a completely closed cell (Millero et al., 1993). The system is composed by a motor driven piston burette (5 mL, scale ± 0.01 mL) with anti-diffusion tip, titration cell assembly, and personal 0.02 computer for controlling burette and data acquisition from pH meter. Orion double junction Ag/AgCl reference electrode and ROSS glass electrode are used as reference and EMF electrodes, respectively. The titration cell and burette piston are inco rporated with outer water jackets which constant temperature (25.0 +- 0.1C) water circulates through. The titration procedure is controlled by personal computer through serial ports. Total alkalinity is calculated by non-linear least squares approach method (Dickson, 1981; Johansson and Wedborg, 1982; DOE, 1994).
Total alkalinity is normalized by Dicksons CRMs (Batch #46) which are measured at every station. It take 40 to 50 minutes to complete titration including flushing. The average precision of duplicate analysis is 4.5 umol kg-1 in one standad deviation.
POI used Bruevich's Method. In Russia a determination of total alkalinity is direct colorimetric titration by hydrochloric acid in an open system using a mixed indicator (methylene blue and methyl red). The titration is carried out under flow of CO2-free air (or nitrogen). The change of the sample color from green to light-pink at the equivalence point is detected by visually. The pH at the end point is about 5.4-5.5. The method is well-known as Bruevich's method (Bruevich, 1944) and recommended as standard operating procedure among Russian oceanographers (The methods..., 1978). The titration procedure is presented below.
The acid (~0.03 N) is standardized daily with Dickson's CRM. The calibrated 0.04 volumetric pipette (25 mL) is used. Twenty-five milliliters of the primary standard is placed in a titration cell. Three drops of the mixed indicator are added and the sample is flushed with nitrogen for 3 min to remove all the carbon dioxide. CRM is then titrated with hydrochloric acid using Dosimat 665 motor driven piston burette (5 mL, scale ± 0.01 mL). The equivalence point of the titration is determined 0.02 colorimetrically. The solution color at the end point of the titration must be light pink and quite stable (no change for 1 min). Seawater samples are analyzed using the same procedure. Total titration time takes about 7 min. Alkalinity is calculated by formula
Here, Na, and Va, are normality and volume of acid, respectively; Vsw and dsw are volume and density of seawater. Estimated precision is about 0.2% (4 ~ 5 umol kg-1).
The both methods are summarized briefly in Table 1.
Table 1. Summary of the methods for total alkalinity (TA) and pH by Seoul National University (SNU) and Pacific Oceanography Institute (POI)
SNU |
POI |
||
TA |
Cell type |
Closed |
Open |
End Pt detection |
EMF |
Visual Indicator |
|
Calculation |
Non-linear Least Square < /TD> |
Algebraic formula |
|
Acid |
~ 0.25 N HCl |
~ 0.02 N HCl |
|
Acid Std. |
Na2CO3 and CRM |
Na2CO3 and CRM |
|
Precision |
4.5 umol kg-1 |
4 ~ 5 umol kg-1 |
|
PH |
Spectrophotometry Using mCP |
EMF Without liquid junction |
|
Precision |
0.006 |
0.004 |
Materials
During the Hahnaro-7 expedition in the East(Japan) Sea from 24th June to 17th July, 1999, around 130 real seawater samples from the surface to more than 3500 m depth at 12 stations were used for intercomparison (Table 2).
Table 2. Locations, water depth (in meters), and number of samples of each station for intercomparison of total alkalinity and pH measurements between SNU and POI.
Sta. # |
Latitude |
Longitude |
Depth |
No. of Samples |
4 |
34 49.9 N |
130 11.9 E |
124 |
7 |
13 |
36 12.0 N |
132 27.6 E |
1074 |
10 |
26 |
37 3.45 N |
130 56.2 E |
2207 |
7 |
41 |
37 53.7 N |
129 44.1 E |
1626 |
8 |
45 |
37 53.8 N |
132 41.8 E |
2530 |
11 |
57 |
40 50.0 N |
134 00.0 E |
3530 |
13 |
58 |
41 10.0 N |
136 20.0 E |
3450 |
13 |
72 |
37 11.0 N |
135 32.1 E |
1739 |
13 |
77 |
38 38.0 N |
136 00.0 E |
2725 |
12 |
80 |
39 59.8 |
138 00.1 E |
2420 |
11 |
95 |
42 0.00 N |
138 00.0 E |
3585 |
13 |
108 |
43 47 N |
138 50 E |
2970 |
? |
Results
Total Hydrogen Ion Concentration (pH). The pH values of two laboratories are in a good agreement (Fig. 1). However, the slope between two data sets is about 5 % greater than equivalence (pHPOI = 1.056 x pHSNU - 0.479, r2=0.991). The differences between two are almost within 0 +- 0.1 when pH value is higher than 7.8 with some exceptions. While, in the case of smaller pH values than 7.8, the differences increase linearly as pH values decrease. It becomes about 0.35 at pH value of 7.5 (Fig. 2). This difference (0.35) is not negligible compared with precisions of both methods (0.004 ~ 0.006). Since typical profile of pH in the region (East/Japan Sea) shows around 7.5 of pH from 200 ~ 300 m depth to the bottom (Fig. 3), it can be said that there are differences in vertical distributions between two methods. The reason of the difference is to be studied carefully in the future.
Total Alkalinity (TA). Normalized total alkalinity (NTA = TA x 35/S; S represents salinity) values of two laboratories show linear relationship, in general. How ever, it is seemed that there is a systematic difference between two methods (Fig. 4). POI values (open cell) are smaller to about 5 ~ 10 umol kg-1 than SNU values (closed cell). In the PICES WG13 intercomparison workshop, which was held at Tsukuba, Japan in April, 1999, the closed system shows higher values and open system shows lower than mean values for samples of high pCO2 concentration. This study gives coincident results with those of the PICES intercomparison workshop.
The differences between two methods increase as NTA increases until NTA reaches around 2330 ~ 2340 umol kg-1, and then it can be said that the differences keep constant in the range of NTA higher than 2340 umol kg-1 (Fig. 5). From the vertical profiles, NTA of this range is found within 100 and 500 m (Fig. 3), which is similar with the depth which shows constant pH differences.
The causes of the differences between two methods will be studied carefully in the future.
References
Bruevich C.V. 1944. Determination alkalinity of small volumes of seawater by direct titration. In: Instruction of chemical investigation of seawater. Glavsevmorput, M.-L., 83p.
Clayton, T.D. and R.H. Byrn, 1993. Spectrophotometric seawater pH measurements: total hydrogen ion concentration scale calibration of m-cresol peurple and at-sea results. Deep-Sea Res., 40: 2115-2129.
DOE, 1994. Handbook of methods for the analysis of the various parameters of the carbon dioxide system in sea water. Version 2, A.G. Dickson and C. Goyet eds., ORNL/CDIAC-74
Dickson, A.G., 1981. An exact definition of total alkalinity and a procedure for the estimation of alkalinity and total inorganic carbon from titration data. Deep-Sea Res., 28A; 609-623.
Ivanenkov V., O, Bordovsky, 1978. The methods of hydrochemical investigation of the ocean. 271p. Nauka, Moscow, (in Russian).
Johansson, O. and M. Wedborg, 1982. On the evaluation of potentiometric titrations of seawater with hydrochloric acid. Oceanol. Acta, 5: 209- 218.
Millero, F.J., J.-Z. Zhang, K. Lee, and D.M. Campbell, 1993. Titration alkalinity of seawater. Mar. Chem., 44: 153-166.
Park, K., 1969. Oceanic CO2 system: an evaluation of ten methods of investigation. Limnol. Oceanogr., 14: 179-186.
Pitzer K.S. Ion interaction approach: Theory and data correlation.// Activity coefficients in electrolyte solutions. 2nd Edition/ K.S.Pitzer Ed. Roca Raton Ann Arbor Boston London: CRC Press, 1991. p.75-153.
Sarmiento, J.L., R. Murnane, and C.Le.Quere, 1995. Air-sea CO 2 transfer and the carbon budget of the North Atlantic. Phil. Trans. R. Soc. Lond. B, 348: 211-219.
Skirrow, G., 1975. The dissolved gases-carbon dioxide. In Chemical Oceanography, v. 2, J.P. Riley and G. Skirrow eds., 1-912.
Tishchenko P.Ya. and G. Yu. Pavlova, 1999. Standardization of pH measurements of seawater by Pitzer's method. In: CO2 in the Oceans, Extended Abstracts, Tsukuba.
Volk, T. and M.I. Hoffert, 1985. Ocean carbon pumps: Analysis of relative strength and efficiencies in ocean-driven atmospheric CO2 changes. In The carbon cycle and atmospheric CO2: natural variations archean to present, E.T. Sundquist and W.S. Broecker eds., 99-110.
Figure Captions
Fig. 1 A plot of pH values from SNU and POI. The units are in total hydrogen ion scale (THIS).
Fig. 2 A plot of pH differences between two methods vs. pH values of SNU. The units are same as Fig. 1.
Fig. 3 Vertical distributions of pH and normalized total alkalinity (NTA) for all stations. The units of NTA are in umol kg-1. The depths are from the wire out data.
Fig. 4 A plot of normalized total alkalinity (NTA) values from SNU and POI. The units are same as Fig. 3.
Fig. 5 A plot of NTA differences between two methods vs. NTA values of SNU. The units are same as Fig. 3.
280 water samples from 22 stations, located mainly in the deepest parts of the basins and also in the straits, were collected for noble gas and tritium analysis. Water samples were collected from the rosette in 15mm diameter copper tube for analysis of helium, neon, argon and possibly krypton and xenon. The copper tube was cold sealed and the samples were packed safely for later analysis. All noble gas samples were collected in duplicate and several samples were collected in quadruplicate. The noble gas measurements will help to quantify the influence that the seasonal sea ice in the Tatarskiy Strait has on water mass formation in the Japan/East Sea.
Samples for tritium analysis were collected concurrently to the noble gas samples so that tritium/helium dating is possible. These samples were collected in one litre glass bottles that had been pretreated by heating to 200 degrees centigrade in an argon atmosphere. During sampling the bottles were not rinsed and a head space was left. These samples were also packed for later analysis at the Noble Gas Laboratory at the University of Southampton, U.K.
100 water samples from 11 stations were collected in 300ml glass
bottles for the analysis of oxygen isotopes. The glass bottles had
been treated in the same way as those for tritium analysis. The stations
chosen for the noble gas and tritium analysis as the volumes of water
taken in the samples may be sufficient to allow both tritium and
oxygen isotope analysis from both the 1 litre and 300 ml bottles
thereby providing more data.
B.11.a. Lowered ADCP.
A 150 KHz RD Instruments acoustic doppler current profiler was integrated
with the CTD/rosette
package. The LADCP makes direct current measurements at the depth of the CTD, thus
providing a full profile of velocity. The LADCP was used at every station.
The shipboard data acquisition system for the LADCP permits
data acquisition on a laptop PC and very preliminary processing on a small Sparc
workstation. When the data set is returned
to SIO and the U. of Hawaii, preliminary processing will determine if the data set
is useful for processing. Criteria include the presence of scatterers in the water
column and good data profiles. Assuming that the data set is useful,
data processing will be carried out by Scripps and U. Hawaii researchers
Preliminary profiles plotted from the LADCP at sea indicate that the data
set looks promising and useful.
(Talley group at SIO; Hacker/Firing group at U. Hawaii).
B.11.b. Underway ADCP.
ADCP data were recorded by the Revelle computer system. Rudimentary
processing was carried out during the cruise to ensure that data files
were complete.
Preliminary checks suggest that no data were recorded for the interval
between CTD stations 57 and 58.
IMET data were recorded at 30 sec intervals on the ship's underway
system.
Sensors:
Air Temp, RH, Barometric pressure, SWR, LWR, Precipitation,
Wind Speed/Direction, Sea Surface Temperature/Conductivity.
Data merged with Ships navigation, gyro and time server.
Navigation was recorded from both a P-code GPS and an Ashtech GPS. The
P-code recorded data were corrupted
for the period July 7, 1999 at 1043 to July 7, 1999 at 2356.
Positions were restored from the Ashtech GPS for this period for the
data file that was
distributed at the conclusion of the cruise.
There was apparently no problem with the real-time positions displayed
on the bridge and in the lab, and so the station positions are correct.
Underway bathymetry from the center return of the Revelle's
Seabeam was recorded and stored for use with the vertical sections.
Bathymetry from the Knudsen echosounder was also recorded, and was used
to
restore
portions of the Seabeam bathymetry which were not recorded. These
include
the Tsushima Strait section (stations 1 to 7) and the segment between
stations
27 and 29, at times 990629 0453, June 29 to 0939, June 29. The Knudsen
echosounder
also was not functioning for a portion of the missing Tsushima Strait
section
and so detailed underway bathymetry is not available for this portion.
We described aspects of the biological oceanography of the Japan/East
Sea, in
particular how plankton communities and abundances changed in the
different
hydrographic regimes. Our research had three primary objectives: 1) To
characterize the
zooplankton community of the Japan Sea in terms of taxonomic composition
and size
structure, 2) To characterize the scales of variability of the
zooplankton
over distances from
centimeters to hundreds of kilometers, and 3) to determine the
relationship
between
zooplankton taxa and associated environmental variables over scales from
centimeters to
hundreds of kilometers. To achieve these goals, we conducted a survey
of the southern
Japan Sea using the Video Plankton Recorder. The Video Plankton
Recorder (VPR) is
essentially an underwater microscope which images plankton at two
different
magnifications. The instrument is mounted on a V-fin which was towed
behind the ship,
undulating between the surface and a selected depth. Video images and
associated
hydrographic and biological data are transmitted from the towed vehicle
to
the ship via fiber
optic cable. In-focus images of plankton are extracted from the video
and
identified to taxa
in real time. Plankton abundances and hydrography are plotted in real
time.
During the survey of the JES, we towed the VPR at ~9 knots between all
CTD
stations along the transect lines. We sampled over a total distance of
356
2 kilometers and
collected and processed over 240 hours of video and associated data.
The instrument
sampled between near surface and 80 m for much of the survey with an
inter-
profile
distance of ~7 kilometers.
In addition to the plankton images, we collected pressure,
temperature, conductivity, fluorescence, light transmission, and ambient
light data as well
as logging P-Code GPS position and time (UTC) and Knudsen Echo Sounder
depth.
Real-time plots of hydrographic (T, S, density) and biological
(fluorescence, light
transmission, unidentified copepods, diatom chains, and Oithona) showed
strong vertical
structure in plankton distributions that were associated with the
physical
environment (e.g.,
thermocline) and regional differences in the type and abundance of
plankton.
Future
analyses will include: 1) describing the size distribution of taxa, 2)
quantifying associations
between different taxa and between taxa and environmental conditions, 3)
examining the
scale of variability of the distributions of zooplankton taxa, and4)
incorporating
instantaneous velocity measurements collected with the shipboard
acoustic Doppler current
profiler to estimate of flux of plankton between different hydrographic
regions and in and
out of the JES.
There are three primary goals of the work:
1. Calibration and validation of SeaWiFS Ocean Color satellite. Above
water
spectral reflectance and atmospheric optical depth was collected with a
SIMBAD hand-held radiometer during day-time CTD profiles. The SIMBAD
views
the ocean surface from above, and the
direct beam of the sun to derive spectral reflectance. This above-water
optics
was supported by water samples including preparations for chlorophyll a,
HPLC pigments, absorption by particles and soluble material, particulate
organic carbon and inorganic minerals.
2. Parameterizations of ocean attenuation and chlorophyll specific
absorption
for ocean photosynthesis models. Samples were collected within the
euphotic zone,
as determined by Secchi Depth, to characterize both particle and
soluble
absorption coefficients. The particulate material was partitioned to
phytoplankton and detrital components using methanol extraction and
difference
spectroscopy. Chlorophyll-specific phytoplankton absorption
coefficients will
be used for photosynthesis models. The total particle and soluble
absorption
will be used to model spectral attenuation coefficients of the euphotic
zone.
3. Application of beam attenuation coefficient as an augmentation to
CTD
hydrographic profiles for determining water mass structure and
circulation.
Red and blue wavelength beam attenuation meters (transmissometers) are
integrated with the SIO CTD system and data were collected for all CTD
profiles. Water samples through out the full depth of the profiles were
collected from selected stations and selected depths to characterize
particulate organic carbon, particle and soluble absorption, and
presence of
different mineral components. Attenuation coefficients will be
correlated to
vertical structure in hydrographic parameters including oxygen,
nutrients,
salinity and temperature.
Wet Labs Cstar beam attenuation meter (red) CST-245DR
B.8. Oxygen Isotope Sampling: Clare Postlethwaite (SOC)
B.9. Other SNU sampling (helium, tritium, D-14, Del 18O, SF6): Dong-Jin Kang (SNU)
Samples for other tracers were collected for SNU.
The numbers of stations for each
tracer are 9 for helium and tritium, 6 for C-14, 23 for Del 18O of water,
and 1 for SF6. All of these will be measured in the laboratory.
Helium and tritium will be determined by noble gas mass spectrometer after
series of pretreatment. C-14 will be measured by Accelerating Mass
Spectrometer from CO2 extracted in seawater. Del 18O will be analyzed using
stable isotope ratio mass spectrometer. SF6 will be measured by GC/ECD.
B.10. Underway pCO2 measurements: Dong-Jin Kang, Doshik Hahm (SNU)
B.11. Acoustic doppler current profiling (ADCP): Lynne Talley (SIO)
and Peter Hacker (U. Hawaii)
B.12. Meteorology: R/V Revelle (Talley; SIO)
B.13. Navigation: R/V Revelle (Talley; SIO)
B.14. Bathymetry: R/V Revelle (Talley; SIO)
B.15. Video Plankton Recorder (VPR): Carin Ashjian (WHOI)
B.16. Plankton net tows: Carin Ashjian and Cabell Davis (WHOI)
We conducted 15
plankton tows using a 1-m2 (mouth area), 150 B5m mesh ring net towed
obliquely between
the surface and 80 m. Initial inspection of the samples indicated strong
variation in
taxonomic composition between the different regions. The plankton
samples
assisted us in
identifying exotic taxa that were seen in the video images.
B.17. Bio-optical studies: Greg Mitchell (SIO)
Wet Labs Cstar beam attenuation meter (blue) CST-244DB
Varian Cary 1E UV/Visible spectrophotometer 95061306
Univ. Lille SIMBAD ocean reflectance radiometer 972308