Monterey Bay Aquarium Research Institute

Hawaii Cruise
March 13, 2001 to June 2, 2001
Monterey to Hawaii and back
Logbook

April 14, 2001: Leg 2; Day 14


Some of the Western Flyer crew taking a short break off of the Kona Coast.

Jenny Paduan writes: Aloha! We are enroute to the leeward sides of Kahoolawe and Maui, crossing the channel between Hawaii and Maui at the moment. It's a sunny day, with gale-force wind warnings for the channel. There are whitecaps everywhere on the brilliantly blue water.

We saw the Southern Cross last night! At about 1:00 AM it was near its zenith low on the southern horizon (the southernmost star, Acrux, is about 7 degrees above the horizon at this latitude). We saw a brilliant meteor and could hear the breaths and see the splashes of some dolphins swimming at our bow. It was a pleasant way to finish off a busy evening of sample processing.

Below are some images from our dives yesterday. Click to enlarge



Sampling an ancient coral fragment in growth position.

An Iridigorgia gorgonian (home to a small crab) with a small Primnoid gorgonian at its base.

Phosporite (black) and coral (white) fragments litter the upper terrace of the ancient reef (a push-core handle is in the foreground). 

Ancient coral patch-reef eroded into a bizarre shape several meters high.

Log Entry: After a long and sloppy crossing of the Alenuihaha Channel between Hawaii and Maui, we arrived at the southwest rift zone of Kahoolawe Island, only to discover that the site was not really in the lee of the Islands and that the wind was still blowing 30-35 knots. Another 2 hours brought us to a series of drowned coral reefs just south of Lanai Island, where we finally were able to dive. These reefs are similar to those on Mahukona and formed on a sinking island as sea level fluctuated during glacial/interglacial periods. However, none of the Lanai reefs has been reliably dated, so we do not know how they fit into the history of the islands.


Second Mate Steven Phillips on the bridge.

The first of two short dives began in mid-afternoon on a terrace at about 550-meters depth. We landed among small blocks and low-relief outcrops of limestone in a generally muddy bottom. Our traverse took us up the reef face, which rises only about 50-meters. The reef face was gentle and the outcrops barely jutted through the sediment cover. We collected a number of samples of algal accretions, shell fragments, and carbonate sandstones-but no corals. The absence of corals in this reef suggests that it grew during less optimal times when coralline algae could survive but the water was too cold to support coral growth. We saw a few rounded clasts of basalt during the dive, but observed no lava outcrops. The rocks were apparently beach cobbles transported along the coast when the reef was near the shoreline. A highlight of the dive was an encounter with a large, somewhat stout and stumpy octopus. We spent 10-15 minutes watching him slowly swimming through his underwater world.

A second short dive on the 490-meter terrace was done after dinner. This terrace looked much more similar to ones on Mahukona, with similar sediment cover, large carbonate outcrops, and a steep reef face. And we hit the jackpot - on this dive we discovered a large outcrop of corals still standing in growth position, and collected numerous pieces. Additional coral fragments were recovered from other locations along the reef face, so we should be able to measure the age of this reef and determine whether it formed at the same time as any of the Mahukona terraces.

We have collected so many rock samples that we have run out of containers to store our samples! The small laboratory on the ship is now littered with labeled samples in plastic bags on every available surface (including the floor), and we are running out of places to put any more. It is a good thing the cruise will end Monday and we can pack and ship the samples back to Moss Landing for further description and analysis.

We have decided to stay in the area and try again to dive on the Kahoolawe rift zone on Sunday, when the weather forecast indicates that milder wind and sea conditions should prevail.


 

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