06/10/04 - Glass sponge & black coral
|Lat:||30° 31.0 min N|
|Long:||79° 39.6 min W|
We steamed through the night to a point off the coast of Jacksonville, Florida. Using fathometer (depth) readings, the night watch found a very good location for the first sub dive. Before the sub went in we spotted several short-finned pilot whales off the bow. They surfaced and seemed to hang with their fins above water for several seconds before diving.
The sub went in at 8 am with Ken Sulak in the bow and Co-Principal Investigator and Museum Educator Liz Baird in the stern. The sub descended to a depth of about 1,800 feet (549 m) and arrived at the top of a rise covered with corals, sponges, and anemones. Though there were not many fish, they saw a few rattail fish that looked like the genus Nezumia.
The diversity of sponges was incredible. There were sponges shaped like wine glasses, some like decanters, others that looked like inverted bowls and sponges that had several openings around them. In the phylum Porifera, sponges consist of individual cells living in colonies around a series of canals. Scientists use a sponge's spicules, tiny needlelike structures that make up a sponge's skeleton, to identify the different species. We think many of the samples we found are "glass sponges" - sponges with spicules made out of silica, the same material that composes window glass. We have to wear gloves when we look through samples since the spicules are very fine, almost like fiberglass, and easily stick into your skin.
As they traveled across the bottom, the scientists also caught a quick glimpse of a large, 6-foot shark which swam by the sphere. Positive identification will have to be made later. The sub traversed a swale (low place) which did not have much coral but appeared to be filled with rubble.
When they reached another rise they collected two large pieces of coral. One was another bamboo coral. The scientists hope to take samples from the base and tip of the coral to see if there is any periodicity or regular interval preserved in the rings which give this coral its common name. They also collected a black coral sample which appeared to be orangish-red. Once the orange surface was scraped off, the black coral underneath became quite obvious. When the sub returned to the surface the scientists could see just how large the samples of coral were: both were more than 3 feet tall!
In between dives the crew tried an otter trawl off the starboard side of the ship which caught several fish, lots of coral rubble, and different sponges. Tonight we will do several more of these trawls.
In the afternoon, the sub went down with Martha Nizinski in the bow and Steve Ross in the stern. They returned after dinner with additional coral samples, a few galatheid crabs, and a pair of very small crabs from the genus Munida. These little crabs were shaped like galatheids but were about an inch and a half long with a distinctive white stripe across the middle of their bodies. One of them had eggs tucked under her tail.
The night crew (the folks who work from 6 pm until 6 am) are
looking forward to a night without steaming to a new location.
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