March 2, 2003: Leg 2, Day #1

The seas continued to be calm and pleasant, and the R/V Western Flyer arrived at the Guaymas dive site today in time for an afternoon test dive. We were in the green waters by 2 pm with a variety of sampling gear, ready to finally investigate the great hydrothermal chimneys in this area.

The equipment included a temperature probe, one of the ICL controlled water samplers (see left), a Homerpro acoustic marker, push cores, the ISUS/Eh sensor, and two data loggers to leave behind on the bottom for tomorrow’s dive.

The pilots provided a fantastic, new sampling tool called the “chimney crusher" (see right, below). This metal cylinder was used to pull the tops from small active structures so that the thermocouple arrays could be put into place. These pictures (below) show a nice chimney on top of the12-meter-tall Rebecca’s Roost that was collected by our new device.

The dive proved to be amazingly productive and successful for such a brief time on the bottom. The navigation was accurate enough to let us move around on our maps and identify all the structures. We found great expanses of white bacterial mat and piles of clams on the sediments between the chimneys.

One of the biggest surprises was a channel in the mud spouting hydrothermal fluid (see left) and surrounded by multicolor microbial mats. Low temperature structures in the south looked like great rose bushes covered with tubeworms (see below). We finished the day by launching one of our elevators with water samplers and bioboxes. It will sit on the bottom and await the arrival of the ROV for tomorrow’s dive. Tomorrow, the real work begins as we place the thermocouples in active chimneys and hope the fluids engulf the coils with mineral encrustations.

Debra Stakes