March 13, 2001 to June 2, 2001
Monterey to Hawaii and back
May 16, 2001: Leg 4; Day 8
Kelsey Jordahl writes: We observed a very unusual squid today at approximately 3380 meters off the north coast of Oahu. It swam quite beautifully with its fins, but could also use jet propulsion if it wanted to make speed. It also has the amazing ability to contract and extend its tentacles.
We had a great first day of heat flow dives. Ship, crew, vehicle & instrument performed perfectly. We got heat flow measurements at 15 stations on a line across a small basin on the Hawaiian ridge northwest of Oahu. We used a special heat flow probe on the ROV that measures the temperatures of the seafloor sediments in the upper 60 cm. We use the measurements to determine the amount of heat flowing out of the earth through the seafloor. The values we found were lower than expected, and showed a significant increase towards the edge of the basin. We think that is an indication of water circulation in the basin sediments, and were so intrigued by the results that we changed the plan for Thursday's dives to finish the transect across this basin instead of exploring a new basin.
We also took a number of push cores to measure the thermal properties of the sediments in the laboratory to help to interpret the data from the heat flow probe. On some of our stations, Ed Seidel deployed a trap to try to capture some deep sea shrimp, which looked empty when we packed it up on the seafloor, but actually had captured a few amphipods that were attracted to the bait. We spent the day traversing a flat, well sedimented seafloor, so the few things we saw along the way generated some interest. We picked up two small rocks that were sitting on top of the sediments, and also several aluminum cans that Ed said were good habitats for small octopuses (none were occupied when we recovered them at the surface, however).