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Hawaii Ocean Time-series (HOT)
in the School of Ocean and Earth Science and Technology at the University of Hawai'i at Manoa |
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HOT-127: Chief Scientist ReportChief Scientist: J. DORE
Departed: June 12, 2001 at 0945 (HST)
Returned: June 16, 2001 at 0730
Vessel: R/V Ka'imikai-o-Kanaloa
Operator: University of Hawaii
Master of the Vessel: Captain Ross Barnes
Chief Scientist: John Dore
STAG Electronics Technician: Steve Poulos
STAG Deck Operations: Dave Gravatt
1. SCIENTIFIC OBJECTIVES
The objective of this cruise was to continue building a collection of
hydrographic and biogeochemical data at the Hawaii Ocean Time-series
(HOT) stations. Four stations were to be occupied during the cruise, in
the following order:
1) Station 1, referred to as Station Kahe, is located at 21o 20.6'N, 158o
16.4'W and was to be occupied on June 12 for about 3 hours.
2) Station 2: ALOHA (A Long Term Oligotrophic Habitat Assessment) is
defined as a circle with a 6 nautical mile radius centered at 22o 45'N,
158oW. This is the main HOT station and was to be occupied for 3 days
from June 13 to June 15.
3) Station 8, referred to as HALE-ALOHA is the location of the deep
ocean mooring (20o 20'N, 158o 10.6'W). It was to be occupied on June 15
for about 2 hours.
4) Station 6, referred to as Station Kaena, is located off Kaena Point
at 21o 50.8'N, 158o 21.8'W was to be occupied on June 15 for about 2
hours.
A single CTD cast was to be conducted at Station 1 to collect
continuous profiles of various physical and chemical parameters. Water
samples were to be collected at discrete depths for biogeochemical
measurements.
Upon arrival at Station ALOHA, a net tow was to be conducted, followed
by the deployment of a free-drifting sediment trap array. After
deployment, a full-depth CTD cast was to be conducted, followed by CTD
casts at strict 3 hour intervals for at least 36 hours for continuous
and discrete data collection, followed by another full-depth CTD cast.
Two other free-drifting arrays were to be deployed on June 14: an
oxygen balance experiment for 24 hours and a primary production
experiment for 12 hours. A plankton net was to be deployed near noon
and midnight on June 13 and 14 at Station ALOHA.
After work at Station ALOHA was accomplished, the ship was to transit
to recover the sediment trap array. After the sediment traps were
recovered, the ship was to transit to Station 8, to conduct one
1000-m CTD cast, after which the ship was to transit to station 6.
A near-bottom CTD cast (~2500 m) was to be conducted at Station 6
including salinity samples for calibration, after which the ship was to
transit back to Snug Harbor.
A Profiling Reflectance Radiometer (PRR) was to be deployed for
half-hour periods near noon time on June 12, 13 and 14. A hand-held
photometer belonging to J. Porter was to be used to make aerosol
measurements near noon each day at times coinciding with satellite
overpasses.
An in situ pump for C. Benitez-Nelson's experiments was to be deployed
for 1.5 hr on June 13 and 14.
The following instruments were to collect data throughout the cruise:
a shipboard ADCP, a thermosalinograph and fluorometer, and an
anemometer.
2. SCIENCE PERSONNEL
WOCE group:
Noel Larson Research Associate UH
Jeremiah Johnson (Watch Leader) Research Associate UH
Mark Valenciano Electronics Technician UH
Lal Ratnapala Research Assistant UH
Fernando Santiago-Mandujano Research Associate UH
(Watch Leader)
JGOFS group:
Karin Björkman Research Associate UH
Anne Gasc Research Associate UH
John Dore Chief Scientist (Assoc. Res.) UH
Lance Fujieki Computer Specialist UH
Paul Morris Technician UH
Dale Hebel Research Associate UH
Katsumasa Tanaka Graduate Student UH
Jennifer Brum Technician UH
Colleen Allen Research Associate UH
Ancillary projects:
Tom Gregory Technician UH (Benitez-
Nelson)
Roberta Hamme Graduate Student UW (Emerson)
Laurie Juranek Graduate Student UW (Quay)
3. GENERAL SUMMARY
Operations were conducted as planned without major interruptions.
Thirteen 1000-m CTD casts and two deep casts were obtained at Station
ALOHA. One 1000-m CTD cast was obtained at Station Kahe and two at
Station HALE-ALOHA. One 1000-m cast and one near-bottom cast (~2500
m) were obtained at Station Kaena.
The array of floating sediment traps, the oxygen array and the primary
productivity array were all deployed and recovered without incident.
None of the arrays drifted beyond the edge of the 6 nmi circle
defining Station ALOHA. The sediment traps drifted southwest about 4
nmi from the center of the circle. The Argos satellite was unable to
deliver positions for the oxygen array, perhaps due to the antenna in
the buoy being too close to the water. The strobe on the primary
productivity array appeared to have failed when recovered.
C. Allen and T. Gregory completed successfully 6 plankton net tows.
The in situ pump was successfully deployed as planned, as well as the
PRR. Aerosol measurements were not completed due to cloudy conditions
at the specified satellite crossover times.
Winds were easterlies at 10-20 kt, with 3-6 ft swells.
The ADCP ran without interruption throughout the cruise, as well as
the fluorometer, thermosalinograph, and the ship's anemometer. The
ship's gyro had no problems during this cruise.
We arrived back at Snug Harbor on June 16 at about 0730. Off-loading
of samples and some equipment took place immediately. The lab vans,
incubators and deck equipment were left on board for the next cruise.
4. R/V KA'IMIKAI-O-KANALOA, OFFICERS AND CREW, TECHNICAL SUPPORT
The R/V Ka'imikai-o-Kanaloa and her crew continue to deliver excellent
ship support for our work. The officers and crew were most helpful and
accommodating. They showed enthusiasm and concern for our work and
were very flexible in receiving changes in our operational schedule.
Technical support during this cruise was excellent. STAG personnel
were available at any time to assist in our work and made things much
easier for us.
The refrigerated circulator pump for our on-deck incubator system
continues to experience problems when the ship's engines are on full,
despite the improvements the Chief Engineer has made to the 220V power
conditioning. This problem does not impact operations while on station
at ALOHA, but prevents successful operation of the system during
transits.
5. DAILY REPORT OF ACTIVITIES (HST)
June 8, 2001; Loading Day
Equipment loaded on this day. Tested CTD system.
June 12, 2001
The ship departed from Snug harbor at 0945, delayed by ship traffic in
Honolulu Harbor. Fire and abandon ship drills were conducted at 1015,
followed by a short science meeting during which the cruise schedule
was reviewed, and safety issues were discussed.
We arrived at Kahe station at 1230 and a weight cast (400 lb) to 1000m
was conducted. At 1330 the Profiling Reflectance Radiometer (PRR)
was deployed.
The CTD cast was conducted at 1400, after which the ship headed
towards station ALOHA.
June 13, 2001
We arrived at station ALOHA at 0045 and proceeded to conduct a net
tow, followed by the deployment of the sediment traps. The trap array
was released at 0245. The first deep WOCE cast started at 0300 and was
followed by the shallow WOCE cast, which initiated the 36-hr CTD cast
period. A total of six 1000-m CTD casts were conducted this day.
One net tow was conducted at noon and two at night.
The PRR was deployed at 1230.
The in situ pump was deployed at 1500.
Winds were 20 kt easterlies and 4-6 ft seas.
June 14, 2001
Seven 1000-m CTD casts were conducted during this day, ending the
36-hr CTD cast period at 2000. A second deep cast was started at
2300.
The oxygen array was deployed at 0330.
The primary productivity array was deployed at 0530 and was retrieved
at 1900. The array drifted some 2 nmi southwest from Station ALOHA.
The strobe appeared to be malfunctioning upon retrieval.
Two net tows were conducted in the day and one at night.
The PRR was deployed at 1230.
The in situ pump was deployed at 1500.
Winds were easterlies 10-20 kt, 3-5 ft swells.
June 15, 2001
The second deep CTD cast that started at 2300 on 6/14 was completed by
0230.
The oxygen array was recovered at 0600. The array drifted about 3 nm
southwest from Station ALOHA.
The sediment trap array was recovered at 0730. The array drifted about
4 nm southwest from Station ALOHA.
A 1000-m CTD cast was conducted at the HALE-ALOHA station at 1200.
Being ahead of schedule, an additional 700 m cast was conducted in
order to test a STAG oxygen sensor. Both oxygen traces looked good
but with an offset of about 50 µmol/kg.
A CTD cast at Station Kaena began at 1820, but was stopped at 1088
dbar due to glitches in conductivity data. A new cable was installed
and a second, near-bottom cast (~2500 m) was started at 1950 and
completed at 2125.
Winds were easterlies 10-15 kt, 3-4 ft swells. There was a lot of rain
during the morning hours but the afternoon was sunny.
June 16, 2001
Arrived at Snug Harbor at 0730 and off-loaded samples and some
equipment. Lab vans, incubators and deck equipment were left aboard
for the next cruise.
Sub component programs:
Investigator: Project:
----------------- ----------
Bob Bidigare HPLC pigments/UH
Mike Landry zooplankton dynamics/UH
Ancillary programs:
Investigator: Project:
----------------- ----------
Charles Keeling CO2 dynamics and intercalibration/SIO
Paul Quay DI13C and O isotopes/UW
Steve Emerson O2, N2, Ar, Ne dynamics/UW
John Porter aerosols/UH [not collected due to clouds]
Mark Abbott/Ricardo Letelier optical measurements/OSU
Claudia Benitez-Nelson P isotopes, thorium/UH
Peter J. LeB. Williams oxygen balance/U Wales Bangor
Others:
Investigator: Project:
----------------- ----------
Dale Hebel EOC production /UH
Karin Björkman phosphorus cycling/UH
John Dore N2 fixation, PIC, P15N/UH
Jennifer Brum dissolved DNA, viruses/UH
Paul Morris oxygen balance/UH
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