08/21/03 - Bioluminescence
After ominous-looking rain clouds yesterday afternoon that sent the media back on their way to port 20 minutes ahead of schedule, the skies cleared once again, and a glistening sun set over the distant horizon. Early morning trawling netted some squid and jellies, and a variety of fishes including numerous Leptocephali (eel larva) which were examined under microscope for species identification.
Before daybreak, we steamed towards this morning's scheduled dive site. Sonar images from the ship's fathometer were tracked, and the profile they presented sketched, to get a better picture of the ocean floor. Where the sonar hits hard substrate, the image reflected creates a solid line on the computer-drawn profile. It is theorized that where Lophelia and other corals are located, much of the sonar is absorbed by the coral, resulting in a scattered and choppy looking profile pattern. Therefore these images can be used to help maximize potential diving where Lophelia grows in abundance.
As results from this morning's dive indicated, not only was the site right on target, but the diversity of species seen living in this unique habitat, including those collected, was spectacular.
The afternoon dive focused on collecting additional deepwater video footage. Art Howard, photographer, and Allen Brooks with USGS spent about four hours filming in this incredible environment. They were surprised that they did not see more big fish but were amazed by the bioluminescence. We will continue to study this area tonight by putting several trawls and nets in the water. Nighttime is a good time to sample because many fish rise to the surface in the dark.
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