HOT-114: Chief Scientist Report

Chief Scientist: F. SANTIAGO-MANDUJANO

           HOT-114 Chief Scientist's Cruise Report
                R/V Ka'Imikai-O-Kanaloa
                   24-27 April 2000

Departed:  April 24, 2000 at 0900 (HST)
Returned:  April 27, 2000 at 2000
Vessel:  R/V Ka'Imikai-O-Kanaloa
Operator:  University of Hawaii
Master of the Vessel: Captain Robert Hayes
Chief Scientist: Fernando Santiago-Mandujano
STAG Electronics Technician: Wil Hervig
STAG Deck Operations: David Gravatt

1.  SCIENTIFIC OBJECTIVES

 The objective of this cruise was to maintain a collection of
hydrographic and biogeochemical data at the Hawaii Ocean Time-series
(HOT) stations. Two 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 April 24 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 22 45'N, 
158W. This is the main HOT station and was to be occupied for 3 days 
from April 25 to 27.

 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 plankton net tow would be conducted.
Afterwards a free-drifting sediment trap array was to be deployed for
about 52 hours to measure sedimentation rates of particulate matter.
After deployment, CTD casts at strict 3 hour intervals were to be
conducted continuously for at least 36 hours for continuous and
discrete data collection. The ship was to be requested to remain on
station during this sampling period. Another free-drifting array was to
be deployed for 12 hours for a primary production experiment on April
26. A plankton net was to be deployed near noon and midnight on April
25 and 26 at Station ALOHA.

 After work at Station ALOHA was accomplished, the ship was to transit
to recover the sediment traps, after which the ship was to transit back
to Snug Harbor.

 The following instruments were to collect data throughout the cruise: a
shipboard ADCP and a thermosalinograph.


2.  	SCIENCE PERSONNEL

WOCE group:
 Fernando Santiago-Mandujano	 Chief Scientist (Res. Assoc.)	UH
 Don Wright     (Watch Leader)   Research Associate       	UH
 Mark Valenciano                 Electronics Technician     	UH
 Michelle Eich                   Graduate Student           	UH
 Lal Ratnapala			 Student Assistant		UH

JGOFS group:
 Karin Bjorkman                  Research Associate             UH
 Terrence Houlihan 		 Research Associate		UH 
 Louie Tupas    (Watch Leader)   Scientist (co-PI JGOFS) 	UH
 Dale Hebel     (Watch Leader)   Scientist (co-PI JGOFS) 	UH
 Lance Fujieki                   Computer Specialist          	UH
 Daniel Sadler                   Research Associate         	UH
 Matt Church 			 Graduate Student     		UH

Ancillary projects:
 Coleen Allen                    Research Associate    UH - M. Landry


3.  GENERAL SUMMARY

 
 Operations were conducted as planned without any incidents. All the
primary JGOFS and WOCE objectives were accomplished. One 1000 m CTD
cast was obtained at Station Kahe, and a total of 15 were conducted at
Station ALOHA including two deep casts.

 One 8-bottle go-flo cast was successfully obtained at station ALOHA,
and the primary productivity array was deployed for 12 hr and
recovered without problems. The array of floating sediment traps was
also deployed for about 52 hr and recovered without incidents. C.
Allen completed successfully 6 plankton net tows.

 A strong near-surface northwestward current of about 1 kt was present
during the cruise as indicated by the ADCP and by the drift of the
primary productivity array and the sediment traps. This strong current
caused some difficulties during the deployment of the primary
productivity array and during the recovery of the sediment traps. The
difficulties were resolved and in the future measures will be taken to
adjust deployment procedures when strong currents are present.

 Conditions were slightly rough during the transit to Station ALOHA due
to the big swell, but improved afterwards.

 The ADCP ran without interruption throughout the cruise, as well as the
thermosalinograph. Some tests were conducted by the WOCE group on the
continuous water supply system to investigate their effect on the
thermosalinograph.

 We arrived back at Snug Harbor on April 27 at 2000. Off-loading of
all the equipment took place on April 28.


4.  R/V KA'IMIKAI-O-KANALOA, OFFICERS AND CREW, TECHNICAL SUPPORT

 The R/V Ka'Imikai-O-Kanaloa provided appropriate 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 very good. STAG personnel were
available at any time to assist in our work and made things much easier
for us.

 During the last two days of the cruise solvent fumes (apparently caused
by painting in some area of the ship) went into the Rock Lab (CTD Lab)
through the AC system, making it difficult for the science personnel to
work in the Lab. This was communicated to the bridge.
 

5.  DAILY REPORT OF ACTIVITIES (HST)

April 17, 2000; Loading Day

 A full equipment load was conducted by the JGOFS and WOCE groups and
ancillary investigators.  M. Valenciano made a CTD cable re-termination
in the evening of April 16.


April 24, 2000

 The ship departed from Snug harbor at 0900. Fire and abandon ship drills
conducted at 0930, followed by a short science meeting during which the
cruise schedule was reviewed, and safety issues were addressed.

 Arrived to Kahe station at 1145 and a weight cast (400 lb) to 1000 m
was conducted during which M. Valenciano inspected the CTD wire. At
1300 the Profiling Reflectance Radiometer was deployed.

  A 1000 m CTD cast was conducted at 1400, after which the ship departed to
Station ALOHA. The transit to ALOHA was rough because of the swell (6-8 ft
from 70 deg). Seas were 3 ft from 90 deg, and winds were 20 kt from 80 deg.


April 25, 2000.

 Arrived at station ALOHA at 0030 and conducted a net tow, followed
by the deployment of the sediment trap array. A deep CTD cast started
at 0400). The 36-hour CTD cast period started at 0900 with the shallow
WOCE cast. A total of five 1000 m CTD cast were conducted this day.

 Two net tows were conducted during the day and one at night.

 Winds were 17 kt from 90 deg, swell was 5 ft from 95 deg, and
sea was 3 ft from 90 deg.
 

April 26, 2000.

 Operations continued as scheduled. A total of eight 1000 m CTD casts
were conducted, completing the 36 hour period. An 8 bottle go-flo cast 
was conducted at 0200. Problems with one of the bottle's firing mechanism 
and with a messenger hung up along the line caused a one our delay on this
cast. The JGOFS group is taking measures to prevent this type of delays
in future cruises. 

 The primary productivity array was deployed at 0530. Some difficulties
were encountered during this deployment due to the strong currents. One
of the floats got entangled with the top most spreader bar just before
releasing the array, and had to be partially recovered after
unsuccessfully trying to untangle it using one of the ship's boat
hooks. The array was recovered at 1900 after drifting 10 nm
northwestward.
 
One net tow was conducted during the night and one more during the day.

Swell 5 ft, 95 deg; Seas 3 ft, 70 deg; Winds 19 kt, 70 deg

April 27, 2000

 A second deep CTD cast was conducted starting at 0000, after which we
transited to the location of the sediment trap array as indicated by
the ARGOS positions transmited via e-mail. The array had drifted 23 nm
northwest. Recovery operations took place from 0600 to 0700 with some
difficulties due to the strong current. It was not possible to retrieve
the array's floats and balls without using the ship's crane, an
operation that is usually conducted by hand.

 Transited back to Honolulu, arriving to Snug Harbor at 2000.
 
 Swell 6 ft, 80 deg; Seas 4 ft, 80 deg; Winds 25 kt, 90 deg

April 28, 2000

 Unloading of all the equipment completed by 1200.


6. SUB COMPONENT PROGRAMS AND SPECIAL PROJECTS

B. Bidigare (UH)                    HPLC pigments
M. Landry (UH)                      Zooplankton community structure
K. Bjorkman (UH)                    Phosphorus dynamics
D. Hebel (UH)                       Organic matter exudates
L. Tupas  (UH)                      Primary production intercomparison


7. SAMPLES TAKEN FOR OTHER INVESTIGATORS

1. DIC water samples for Charles Keeling, SIO-UCSD
2. DIC water samples for Paul Quay, UW
3. Phosphorus experiments by Karin Bjorkman, UH
4. Microbial sampling and experiment by Matt Church, UH