|Icy Inverts 2004|
|Daily Journal of the R/V Laurence M. Gould|
|Dec. 17, 2004 --- Position Lat/Long: S064° 48.410 W063° 33.671 |
(~1 p.m. – I got to sleep through my midnight shift!!)
[Wind: 2-3kn / Air Temp: 2.7C / Wind Chill: 2.6C /Depth: 319m / Seas 0ft ]
|We departed Palmer Station at about 10:30 a.m. in sort of gray skies, but with a definite air of celebration. This is the last leg of our journey, the beginning of the trip home. We now have 5 of the Palmer staff of 42 with us, so a bugle was blown at Palmer to beckon all of the hardy souls|| Photo1 || |
who were staying on, and out they came to the dock to see us (and their friends) off. [See Images 1&2] It was a really fine sendoff – we had enjoyed ourselves with enthusiasm at this fine US Research Station, and were privileged to have had a glance at what the dedicated staff who commit themselves to this kind of work, do.
Once again, we were able to transit the beautiful Neumayer Strait (this time in the light of day, and I watched it all from the Bridge), on to the Gerlache again, with a cut through Boyd Strait and then along Livingston Island with its exceptionally large mountain peaks. We made a short pass to the east to Point Shirreff on Livingston I to pick up a 6th new passenger, Mike (we idled a couple of miles offshore while the zodiac went in to retrieve him). We are now out in the Drake Passage again. If I didn’t mention it before, the Drake has the well-deserved reputation of having some of the harshest winds and waters on earth. We are watching the ‘isobars’ in the weather pattern printout to help forecast the conditions ahead of us. At present, they are looking favorable to a gentle passage across to South America, destination Staten Island (then a cut through in the Straits of Magellan and back to Punta Arenas). We have the technology as an aide, but in fact we all have our fingers crossed…
In the final few Journals, I’d like to introduce you to the lead scientists on this cruise, and give you a pinhole of an idea of what they came to do, and what they found out.
Professors Will Jaeckle and Susie Balser of Illinois Wesleyan University
Will’s purpose on this cruise is to capture the larvae live, and try to find out how these critters transport nutrients to all part of their bodies, especially the clear outer ‘skin’. You see, they have a ‘mouth’ and a ‘gut’ or digestive system, but no circulatory system for transport of nutrients like we do. So the question is, do they take food in and move it with microscopic “pumps”, or can it just be distributed by diffusion in a cell-to-cell manner? This is something that had not been studied or written about in any particular detail before, and Will would like to write that paper
Susie Balser, who I must say has the very best eye and specialized patience when it comes to microscopic photography, is a professor of Biology and teaches Invertebrate Zoology. Yup, you’re right, ‘no backbones’ again. Susie is studying pterobranchs on this trip. Pterobranchs are small animals (only about 5 mm in length) that live in tubes on the sea bottom. They use their “feather-gills” (hence the name pterobranch) to capture suspended food such as single-cell plants and animals from the water. In the picture [See Image 5] you can see one large zooid and other smaller zooids—all of which make up what is called a “colony” of interconnected animals. The animals shown have been removed from their tube. Each of the small zooids grows from a disc at the end the large zooids stalk. This animal can have up to 10 other members in its colony.
It is known that peterobranchs are part of the same family tree as humans. But because they are considered especially “primitive”, they present a good starting place to get a handle on the changes that occurred at the beginning of their development as other science looks on up the tree at chordates and eventually us – big vertebrates. Although we’re part of the same ‘tree’, Susie would like to help find out from which ‘branch’ they stem. We pulled many pterobranchs up from the bottom with our benthic tows, and gave them to Susie to look at under her microscope. Prior to this trip, Susie had seen only 2 species of pterobranchs. But it appears that she has seen 4 different species out here this month, and perhaps even a 5th (2 that look similar, but seem to have some differences). This means she may have some up-to-date information on species that hadn’t been described in science in more than 20 years. (This is always good for putting a researcher more visibly “on the map” in respect to their field.)
We will continue for four more days across the Drake Passage, making stops for plankton sampling until we get to Staten Island. The labs are, for the most part, packed up and ready for offloading when we get to the docks in Punta Arenas. No more icebergs, no more grandiose superlatives (is that redundant?) to describe the scenery. From here on in, it’s just humble respect and awe for this long ocean passage, with maybe a fiery sunset or two.