K1-95-HW: Cruise Report 1995 - Preliminary results.

Phase III: Sediment Chemistry and Biological Sampling Survey

M.E. Torresan, M.A. Hampton, J.H. Barber, Jr., and F.L. Wong

U.S. Geological Survey Open-file Report 95-839

1995

This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards. Any use of trade names is for descriptive purposes only and does not imply endorsement by the USGS.

Summary
Introduction
Study Area
Previous Studies
  Designation
  Monitoring 1, 2
Methods
  Vessel
  Navigation
  Sampling
  Subsampling 1, 2
Results
Acknowledgments References 1, 2

Figures
1 Location
2 Box corer

Tables
1 Stations
2 Samples
3 Analyses
4 Bioassay

Appendices
1 Box Cores
2 Custody: Quanterra
3 Custody: Batelle

METHODS

Research Vessel
The survey was conducted aboard the University of Hawaii's R/V Kila, a 192 ton, 104 foot long research vessel. Kila has a 24 foot beam and 12' 11" draft when fully loaded, and was used for all three surveys for the monitoring program that commenced in 1993. Kila has a spacious 16 x 18 ft work deck and is outfitted with a 5-ton deep-sea winch that has 1/2" torsion-balanced wire and a 10-ton A-frame that allowed deployment of the USGS box corer. The vessel and the crew performed flawlessly during the survey.

Navigation
Ship navigation employed a GPS system in either an autonomous or differential mode, with nominal accuracies of about 100 m and 5 m respectively. Details of navigation and GPS technology can be found in Torresan and others (1995), and references cited therein.

Sampling
All bottom samples were collected with a USGS-modified NEL box corer (Figure 2). The box corer is the industry and academic community standard for obtaining undisturbed samples of the upper 20-40 cm of the sediment column. USGS modifications to the NEL box corer include a smaller box (20x30x45 cm vs the standard 20x30x60 cm), lighter weight (1300 lbs vs the standard 1500 lbs), and shorter height (7 ft rather than 9 ft). The most prominent modification is that the box corer is outfitted with a Benthos Model 374, 35 mm bottom camera, a 100 watt-seconds flash unit, a laser light system, and a trigger weight. The camera is loaded with a 50 ft roll of 35 mm film capable of 400 exposures. The camera and flash are mounted to the box core frame and the system takes a photograph of the seafloor directly below the corer, just prior to sampling. The laser beam light system marks two spots on the seafloor that are 7.5 cm apart, and are used for scale.

The box corer is constructed of mild steel and is coated with an inorganic zinc compound and an epoxy primer and overcoat to protect against rust and deterioration. The unit holds a 0.06 m² stainless steel sample box that has a maximum effective penetration of about 40 cm, and a total volume of 0.027 m³. Special features of this box include quick release cams for removing the box, and removable face plate to expose the sample for descriptive, photographic and subsampling purposes. Special features also include a flow-through head design with closing door flaps. The spade is fixed in position and a removable base plate is attached to the sample box before the corer is opened and the sample removed.

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