Leg 2: February 23, 2012
Day 7: Calycophoran catch of the day
Our ROV dive today took us down to 3,200 meters (10,560 feet). We spent just under an hour collecting on the bottom, then slowly made our way back up, leveling off for a short period of time every 400-500 meters (1,320-1,650 feet) to search for animals. We logged another successful 12-hour dive with all samplers filled.
Once more we observed and collected several interesting, deep squids, but the most amazing part of today’s dive was when ROV pilot Eric Martin caught a tiny calycophoran siphonophore in a detritus sampler for our science collaborator, Rebeca Gasca. After the dive the pilots and scientists gathered around to look at the specimen that was only about one centimeter long and completely transparent! Rebeca was excited to get a calycophoran in pristine shape from such a deep depth (over 3,000 meters or 10,000 feet).
From Rebeca Gasca: It has been very exciting being on this cruise, finding, watching, and collecting unfamiliar species with bizarre and sometimes beautiful forms inhabiting the depths of the Gulf of California. When you take a zooplankton net sample you think that is representative of what is there below the surface, but when you dive throughout the sea you can see how different it appears from the image you built in your mind before being right there. I could never imagine the amount and size of siphonophores with their fishing tentacles hanging and covering so much space and fishing so efficiently. Also, to look at the zooplankton in the scattering layer was interesting as we saw many ostracods, appendicularians in their “houses”, medusae, siphonophores, and other drifting animals.
The specimens collected with the zooplankton net and the ROV will be used to conduct taxonomical studies including comparisons between similar species of the same genus. In addition, we will perform DNA studies to get more information to accompany the morphological data that we already have for some of the groups studied, like siphonophores and amphipod crustaceans among others. At El Colegio de la Frontera Sur (ECOSUR) we have people working with several zooplankton groups that are very interested in the material we can get from this cruise. We usually have access to samples from the surface to 200 meters only, so this cruise is an opportunity to get many different species and most of the deeper specimens collected will become important additions to our collections at the Zooplankton Collection of ECOSUR in Chetumal, Quintana Roo, México.
The weather was calm enough that our blue-water divers were able to get into the water this afternoon as well. Four divers collected for an hour, and they came back with just one single specimen! They were shocked and disappointed at the lack of animals in the shallow waters. Fortunately, for Meghan Powers and Steve Haddock the animal they collected was one they have been targeting for luminescence research. Read more about this glowing creature tomorrow.