March 13, 2001 to June 2, 2001
Monterey to Hawaii and back
March 28, 2001: Leg 1; Day 16
Log Entry: Our last science day was yesterday and like the 26th, it was a busy one. The ROV stayed under until late in the night working to a depth of 1420 meters before we called it quits. We filled up every sampler that we had before returning to the moonpool.
While the ROV was diving yesterday, the other groups were busy packing up their gear. We liberated one of the largest Vampryoteuthis specimens that we have ever observed yesterday and also observed some large specimens of a jelly that has several nicknames (Gumdrop, Big Red, and Big Ugly). The first one that we saw was about half a meter in diameter and we thought that was too big to collect. Then we found an even larger one! The sun set over the horizon and around 2100 hours, we recovered the vehicle and recorded the last video shot of this leg.
The goal of this first leg of the Hawaii Expedition was to occupy a series of stations encompassing the three water masses (coastal zone, California Current, and central gyre) that occur along the transit line from Monterey to Honolulu. Data collected at each station will be used to investigate the relationships between iron, primary production, and gelatinous zooplankton. At 9 stations there will be a 6-hour ROV dive (to 1,000 m), a bongo net tow, a CTD cast (to 1,000 m), and a blue-water scuba dive. At 7 additional stations there will be a bongo net tow and CTD casts. Between stations, underway sampling will include a towed-fish pumping system, and continuous recording with the EK-500 echosounder. All ROV dives will be made during daylight hours, preferably between 0800 and 1400 hours, local time.
We met all of our goals and exceeded them with some additional stations added in for both CTD casts and diving. Preliminary analysis of the data has already revealed some interesting results. The concentrations of dissolved iron and aluminum along the Leg 1 transect showed almost an inverse relationship with high iron levels near California and high aluminum levels near Hawaii (see photo from March 25th). This study will continue with Leg 5 of this expedition. The plankton sampling along the transect showed clear to the naked eye even before quantifying the samples (see plankton photo from March 25th). Preliminary results from incubation experiments suggest that microzooplankton grazing rates balance phytoplankton growth rates in the gyre. The CTD data clearly show that we occupied stations in all three targeted water masses (March 20, 21, and 23 photos). The SCUBA transects clearly identified all three water masses as well with different species diversity represented. The ROV transects will take some time to analyze but the data gathered is extremely valuable with distinct zonation patterns vertically and along the transect from California to Hawaii. We discovered some new organisms and were pleased to find some familiar ones (found along California). Overall, Leg 1 was a resounding success with the different scientific groups working well together supported by the Western Flyer and her crew and the ROV pilots - an exceptional group that never hesitated to help out and facilitate our research efforts.
The photographs on these webpages were taken by many different individuals and although credit was not given on these pages, we thank Kevin Raskoff, Rob Sherlock, Steve Haddock, Francisco Chavez, and Ginger Elrod for their photographic skills and willingness to share their images.
We are heading into harbor right now. It is 0710 WFT (0910 PST) and we should be at the University of Hawaii dock by 0900 WFT. Once we arrive, the science crew will be busy off loading all of the gear that we loaded 16 days ago. There will be some additional crew for both the Western Flyer and for the ROV waiting at the dock. There will not be any vacation time for either crew as they will be extremely busy over the next three days preparing for the next leg of the expedition.
Come back and join us on April 1st and you can follow along as David Clague's leg will address topics as diverse as formation of karst topography in drowned reefs to dynamics of submarine basaltic eruptions and formation of volcanic landforms to hydrothermal circulation and geochemistry. Dives are planned to address the interplay of volcanism and reef formation on Mahukona and Kohala (Hilo Ridge) Volcanoes, formation of pointed volcanic cones, flat-topped volcanic cones, and lava ponds on Haleakala, Kilauea, and Koolau Volcanoes, the structure of folded volcanicalstic rocks along the margin of the Hilina slump at Papa'u Seamount, eruption dynamics of fire fountains and explosive eruptions at Loihi Seamount, long-term changes in the hydrothermal system at Loihi Seamount, and formation of karst topography in drowned coral reefs on Mahukona Volcano.
George I. Matsumoto