Hawaii Ocean Time-series (HOT)
in the School of Ocean and Earth Science and Technology at the University of Hawai'i at Manoa


HOT-185: Chief Scientist Report


Chief Scientist: P. LETHABY


             HOT-185 Chief Scientist's Cruise Report
                     R/V Ka'Imikai-O-Kanaloa
                      September 14-18, 2006

Cruise ID: KOK0608
Departed: September 14, 2006 at 0820 (HST)
Returned: September 18, 2006 at 0730
Vessel: R/V Ka'Imikai-O-Kanaloa
Operator: University of Hawaii
Master of the Vessel: Captain Ross Barnes
Chief Scientist: Paul Lethaby
OTG Electronics/Deck Operations Technicians: Steve Poulos, Tim McGovern

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. Five stations were to be occupied during the cruise, in
the following order:  

1) Station 1, referred to as Station Kahe, is located at 21 20.6'N, 158
16.4'W and was to be occupied on September 14 for about 2 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 September 15-17.
  
3) Station 51, is the site of the MOSEAN Mooring, located at 22 45'N,
158 6'W and was to be occupied on the 4th day of the cruise for about
30 minutes.

4) Station 50, is the site of the WHOTS Mooring, located at 22 46.1 N,
157 53.4 W was to be occupied on the 4th day of the cruise for about 30
minutes.

5) Station 6, referred to as Station Kaena, is located off Kaena Point
at 21 50.8'N, 158 21.8'W was to be occupied on the 4th day of the
cruise 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. After these operations, the ship was to transit to
Station ALOHA.

During the transit to ALOHA an autonomous glider was to be deployed
just north of the Kaena ridge in water deeper than 1000m.  The glider
would then make its way to ALOHA and occupy the site for 2-3 months in
virtual mooring mode.  After a test dive and confirmation of data
transmission via the Iridium link to a pilot at UH, the ship was to
continue to Station ALOHA

Upon arrival at Station ALOHA, the free-drifting sediment trap array
was to be deployed. The sediment trap array was to stay in the water
for about 52 hours. This was to be followed by two shallow CTD casts
(<200 m) to collect water for incubation experiments. After this, an
array with incubation experiments (gas array) was to be deployed for 24
hours. A full-depth CTD cast was to be conducted afterwards, followed
by 1000-m CTD casts at strict 3 hour intervals for at least 36 hours
for continuous and discrete data collection, ending with another
full-depth CTD cast.

One free-drifting array was to be deployed for 12 hours for incubation
experiments on September 16.

A plankton net was to be towed near noon and midnight for 30-min
intervals on September 15 and 16 at Station ALOHA.

After CTD work at Station ALOHA was accomplished, the ship was to
transit to recover the floating sediment trap array.

After recovering the sediment traps, the ship was to transit to Sta. 51
to conduct a 200-m CTD cast, and then back to Station ALOHA to conduct
one more 1000-m CTD cast, and light casts (PRR, AC9/FRRf).  The ship
was to transit to Sta. 50 to conduct a 200-m cast.

After operations at station ALOHA ended, the ship was to transit to
Station 6 (Kaena).

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 to back to Snug Harbor.

A Profiling Reflectance Radiometer (PRR) was to be deployed for
half-hour periods near noon time on September 14, 16 and 17.

A package including a Wet Labs AC9, a Chelsea Fast Repetition Rate
Fluorometer (FRRf), and a SeaBird Seacat was to be used to profile the
upper 200 m at Sta. ALOHA at noon time on September 16 and 17, and in
the early morning on September 17.

An Automated Trace Element Sampler (ATE) was to be deployed once on
September 15.

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


2. SCIENCE PERSONNEL

BEACH group:

Cruise Participant 		Title 			Affiliation

Karin Björkman 			Research Specialist 	UH
Susan Curless  - Watch Leader	Research Associate	UH
Ken Doggett 			Research Associate 	UH
Lance Fujieki 			Computer Specialist 	UH
Eric Grabowski - Watch Leader 	Research Associate 	UH
Blake Watkins 			Marine Engineer 	UH
Doug White 			Technician 		UH

PO group:

Paul Lethaby - Chief Scientist 	Research Associate	UH
Fernando Santiago-Mandujano 	Research Associate 	UH
Justin Smith 			Undergraduate Student 	UH
Jefrey Snyder 			Marine Technician 	UH
John Yeh 			Graduate Student 	UH

Others:

Elizabeth Hambleton 		Technician		UH
Steve Tottori 			Marine Technician	UH


3. GENERAL SUMMARY

Nearly all objectives for HOT 185 were successfully completed.
Communication problems with the ATE prevented it's deployment.  The AC9
had a weak MPAK battery and did not function.  All other
activities were completed.

One 1000-m CTD cast was conducted at Kahe station. Twelve 1000-m CTD
casts, two deep casts, and three 200-m casts were conducted at Station
ALOHA. One 200-m cast was conducted near the MOSEAN mooring (station
51) and another 200-m cast was conducted near the WHOTS mooring
(station 50).  One 2500-m cast was conducted at Kaena station.

The array of floating sediment traps, the gas array, and the primary
productivity incubation array were deployed and recovered without
incidents.

Six net tows were conducted, three at night and three during the day.

The AC9/FRRf package was deployed three times, twice at noon and once
at night.  Although the AC9 was deployed along with the FRRf it did not
collect data due to the weak battery pack.

The PRR was deployed three times at noon time.

The Automated Trace-Element Sampler was not deployed because
communications with the instrument were not established.

The ADCP ran without interruption throughout the cruise, as well as the
thermosalinograph, and the ship's two anemometers.

The glider was succesfully deployed just north of the Kaena ridge in
water > 2000m and the test dive was successful.

Winds were southeasterlies between 10 and 20 kt during the cruise.

We arrived back at Snug Harbor on September 18 at 0730. 


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

The R/V Ka'Imikai O Kanaloa continues to maintain the 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. OTG personnel were
available at any time to assist in our work and made things much easier
for us.


5. DAILY REPORT OF ACTIVITIES (HST)

September 13, 2006; Loading Day

Equipment loaded during this day, The CTD wire was inspected,
re-terminated and the CTD system tested.

September 14, 2006

The ship departed from Snug harbor at 0820.  Fire and abandon ship
drills conducted at 0900.  Safety briefing by the First Mate was
conducted at 0930, followed by a science meeting in which cruise
activities were briefly reviewed, and safety issues were addressed.

Arrived at Kahe Station at 1120. CTD wire weight cast (400 lb) to 500m,
during which J. Snyder inspected the CTD wire.  The weight had to be
brought back on board initially as the wire out counter was not
functioning.  The weight cast was restarted at 1140. The Profiling
Reflectance Radiometer (PRR) was deployed at 1200. A 1000-m CTD cast
was conducted at 1335. After the cast ended, the ship headed to station
ALOHA

The ship stopped en route to Station ALOHA at 1455 to deploy an
antonymous glider.  The glider began a test dive at 1720 and was back
at the surface at 1805.  Once the data quality had been confirmed from
the glider pilot at UH the ship continued to Station ALOHA.

September 15, 2006

The ship arrived to Station ALOHA at 0000. The sediment trap array
began to be deployed immediately with the spar being released at 0110.
 
One 200-m CTD cast was conducted at 0130 after the sediment traps
deployment.

One 200-m CTD casts was conducted before the gas array deployment.
The gas array was deployed at 0500.

One deep CTD cast was conducted at 0725.

Five 1000-m CTD casts were conducted this day. 

The ATE sampler was not deployed because communication with the device
could not be established.

Three net tows were conducted at 1000, 1220 and at 2200.

September 16, 2006

Eight 1000-m CTD casts were conducted on this day, and the 36-hr CTD
burst period ended with a second deep cast that started at 2300.

The gas array was recovered at 0700, at 22 45.2'N, 158 6.8'W, about 6.2
nm W from ALOHA Station.
 
The primary productivity array was deployed at 0545 and recovered at
1820 at 22 44.91'N, 158 1.29'W, about 5nm NNW from ALOHA. 

One FRRf cast was conducted at 1300. 

One PRR cast was conducted at noon time.

Three net tows were conducted at 0010 and 1000 and 2200.

September 17, 2006

One 1000-m CTD casts were conducted at ALOHA, and one 200-m CTD cast
near the MOSEAN mooring (Station 51) and a second near the WHOTS
mooring (Station 50).

The sediment traps array was recovered at 0615 at 22 46.3'N, 158
8.7'W.

The array drifted NW approximately 10 nm from ALOHA Station.

One PRR cast was conducted at 1200.

One FRRf cast was conducted at Station ALOHA at 1230.

One near-bottom cast was conducted at Station Kaena (Sta 6).

September 18, 2006

Arrived at Snug Harbor at 0730. Full off-load.


HOT program sub-components:

Investigator:                   Project/Institution:
-----------------               --------------------
Dave Karl                       Core Biogeochemistry/UH
Roger Lukas                     Hydrography/UH
Bob Bidigare                    HPLC pigments/UH
Mike Landry                     Zooplankton dynamics/UH
Mark Abbott/Ricardo Letelier    Optical measurements/OSU

Ancillary programs:

Investigator:                   Project/Institution:
-----------------               --------------------
Charles Keeling                 CO2 dynamics and intercalibration/SIO
Paul Quay                       DI13C and O isotopes/UW
Penny Chisholm                  Prochlorococcus population dynamics/MIT
Zehr/Church/Montoya             Diversity and activities of nitrogen-fixing
                                microorganisms/UH
Elizabeth Hambleton/Mike Rappe  Marine bacterioplankton community
                                structure/UH