Davidson Expedition, January 26 - February 4, 2006
February 1, 2006
January 30, 2006 Davidson Seamount Expedition Log: Day 7
NOAA/MBARI Objectives: Dive “Big Easy” in deep southeast, transect, current measurements, Niskin water samples, biology sample collection.
Today’s dive was absolutely amazing. We started out sampling and then transecting in 3,200 meters water depth in the deep southeast of the Davidson Seamount at the “Big Easy.” The seafloor was mostly mud with some volcanic talus scattered about on the surface giving it the appearance of a lunar landscape. Within minutes of touching down we observed several very bizarre mud walls, which appeared to be the cause of a combination of uplift and erosion.
Before heading upslope we took four Niskin water samples, a current measurement, sampled a very large Lepidisis coral and noticed a submarine cable (see image to left), which the nautical charts show as belonging to AT&T. It was somewhat strange to see something deliberately placed by humans in such a remote location at 3,200 meters below the oceans surface.
We continued our ascent upslope and were pleasantly surprised to find a diverse assemblage of invertebrates including corals from the families Chrysogorgiidae (see image to the right) and Primnoidae, several species of crinoids, several species of sea cucumbers, a benthic siphonophore, and an unidentified mollusk, which may have been a sea hare. Unfortunately the unidentified mollusk escaped because after we dislodged it from the rock it was sitting on it began floating and quickly disappeared.
At the peak of “Big Easy” in 2,300 meters water depth, we found an amazing coral garden that was incredibly diverse (see image left). The community included antipatharians, primnoids, paragorgids, cup corals, sponges, crinoids, the stalked tunicate Culeolus, small bryzoans, crabs, and pycnogonids.
The stalked tunicates were larger and appeared healthier than any Culeolus (see image right) that I have seen. They materialized out of the darkness in the distance as ghost-like cartoon dogs – if such a thing ever existed [SCOOBY-DOO MEETS WES CRAVEN - Lisa Borok's interpretation]. See the image and come up with your own description! We finished the dive by taking a current measurement and rock sample