Dispatch: June 6, 2006

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Day's menu: Roast lamb, Stuffed chix breast, carrots, creamed spinach; Last of the lamb, corned beef and cabbage and noodles, chicken, carrots, spinach, yellow cake, cinnamon rolls, ice cream and cookies.

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In case you’re watching a map, we’re in the north side of Holtedahl Bay which is located in the Bruce Plateau on the west coast of the Antarctic Continent.  Surrounding islands are called the “Fish Islands”, and are named thusly:  Plaice I., Mackerel I., Flounder I., Salmon I., Trout I., and we are closest to Perch I.   Our immediate waterway is Harrison Channel.  We will pass Tadpole I. and Larrouy I. to port.  As we steam north to the Grandidier Channel, we will have large Renaud I. to port.  Another group of islands we will pass are the Llanquihue Islands and little Sphinx I.

We’ve been in some heavy snow this morning, and there was even some exchange of human upper extremity-propelled packed snow orbital bodies between the Main and 02 Decks.  I might even have that on video… Besides snow, we’ve encountered some densely packed surface ice, “1st Year Ice”, about 60cm thick.  It’s tricky to move through this, especially after snow, the captain informs me.  It’s easier to move 2 feet of ice than it is a foot each of ice and snow.  The snow introduces more friction in the action of trying to push the stuff out of our way.  In addition, there are growlers out there that are now blanketed with snow, less contrast in the visual field, and I was appreciating the concentration it took for the captain and mate Joe Abshire to negotiate transit through this ice field.  (I appreciated it almost as much as I did Mozart’s Requiem playing in the background.  Thank you, Marty!)  They could tell where this field would end, though I know not how, and were in contact with all involved to plan the next Station stop, where plankton tows would occur.  It happened just as they said it would.

Rhian Waller’s experiment and observations with her Flabellum corals continues to draw my interest.  Around May 24th, Rhian retrieved some larval bodies from adult corals pulled up in a trawl.  I have previously shown an image of the adult and a larva in early development, remember that?  Well, the ‘babies’ have been developing on tiles in a Tupperware box in a very cold refrigerator, and the changes are remarkable.

Flabellum coral larva at approx. 6 days. (Photo by Rhian Waller)

... and later that same day... (Photo by Susie Balser)

At about this point, they proceeded to attach at a home site.  And these little guys didn’t just attach anywhere - if they didn’t like where they were, they’d detach and find a spot they liked better.  One method that we know they use to travel is to ‘blow themselves up’ or inflate, similar to what anemones are known to do in their adult form.  It makes them lighter, and they can be carried through the water until they’re ready to settle.

Once they’d satisfied themselves with their location, they began to develop.  Dr. Susie Balser of Illinois Wesleyan University has been invaluable in helping Rhian document these changes with some of the beautiful microscope images, so we’re all excited to share in the experience!  When the larvae are sufficiently attached, more maturation occurs.  Rhian has seen them develop working tentacles around a definitive oral (mouth) opening.  She has even learned to feed them!  She carefully introduces live copepods (very small swimming critters, a major contributor to the ocean-going food chain, and which we catch plenty in the plankton nets!) with a pipette across that tiny mouth.  The tentacles immediately begin to move to capture an animal, hold it in place, and finally ingest it.  So cool.

Top View
... then at about 10 days... (Photo by Rhian Waller)

Side View
... we see the tentacles forming. (Photo by Susie Balser)

Rhian feeds the coral every two days, but takes them out to look at them under the microscope twice a day.   The next phase of development likely would be the coral’s laying down of ‘argonite’ or the white calcium outer shell.  It is not known exactly how these coral do that, or at this point, when they do it.  By looking at the developing larvae frequently, some of those questions will begin to be answered.  With this experiment and observation, she can capture and analyze each phase.  This, my friends, is an example of the scientific process  isn’t it fun??!!?!

(Photo by Alexis Janosik)

Getting to Know You

Dr. Nerida Wilson
Nerida Wilson was awarded her undergraduate degree from Melbourne University, in her home country of Australia. She received an honours degree and a PhD from the University of Queensland, where she pursued her passion for sea slugs (nudibranchs). She lived in Indonesia for a while, studying the echinoderm and nudibranch diversity in the Wakatobi National Marine Park, and was a Research Associate at the South Australian Museum before moving to Auburn, Alabama to be a post doc in the Halanych Laboratory. She is currently working on understanding the links between distribution and gene flow for several Antarctic marine invertebrates.

More Science
Lots of krill in the plankton tows, and where there’s krill, there’s something feeding.  Don’t you know it, there is plankton in them cooooooold hills!  Lately, the main catch has been spionid larvae.  Literally hundreds were counted yesterday, and altogether, over 1,000 larvae have been set aside for further study (‘fixed’).

Spionids are a type of segmented worm or Annelid.  These larvae will eventually settle to the benthos (or bottom of the sea) and lose their long defensive hair-like spines. Interestingly, although we have seen thousands of spionid larvae in the plankton samples, we have only seen a few in the benthic samples.  So, where are the adults (the moms and dads must be out here somewhere)???

Spionid larva  it’s hairs are mostly for defensive action. (Photos by Susan Balsar)

Spionid larva curled with hairs out for protection. (Photos by Susan Balsar)



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Last updated May 30, 2006
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