>Seas: ca 1-2 feet (behind Elephant Island) >Winds 11 knots >Temp 3.8 C ; w/ wind chill –1.6C >Location: Latitude 61 degrees 12.29’ S; Longitude 54 degrees 55.38 W

Above: Susie Balser's photograph of Elephant Island. Below: A squid nicknamed "Chile." Click on photos for larger images.

1 December 2004

When I wrote to you last, I mentioned that the ocean in the Drake Passage was relatively calm. As an example of how quickly conditions can change, by 10 p.m. last night the boat was regularly listing to 15 degrees to either side and our view through laboratory porthole was reminiscent of looking into a working washing machine. These conditions made hunting the elusive larva within a single petri dish quite challenging. There was a benefit of these unsettled seas — we have all learned to lean while walking at an equal and opposite angle to that of the vessel. This may seem odd, but it is an effective way to maintain proper contact with the floor.

The compositions of the plankton tows that were taken while we crossed the Drake Passage significantly varied. Towards the northern edge of the Passage, the dominant organisms were single-celled, heterotrophic protists called radiolarians (heterotrophy is the condition where they must capture their food). Approximately 2/3 of the distance across the Passage, the net plankton was dominated by diatoms (unicellular photosynthetic protists). At the easternmost edge of the Passage, the tows were composed almost completely of salps. Salps are a group of holoplanktonic urochordates that belong to same phylum as you and I (Chordata). They are filter-feeding organisms that, as adults, reveal their chordate affinity only by the presence of a perforated pharynx. While looking at the last salp-infested tow, Dr. Balser spied some small teardrop shaped white entities. She said that they look like a “sporozoan protist.” She was absolutely correct in this assessment — they were later identified as an apicomplexan protist (219 folks - remember back to lab #1) that parasitizes salps.

Recently I wondered in writing what conditions must be present to allow for transport of larvae across the Antarctic Circumpolar Current. I was not overwhelmed by responses. So let’s try again. Please propose a plausible mechanism that allows for this dispersal path (and you may work as group(s) to generate a reasoned response). [Hint: Think about what you see in a freshwater stream.]

We have finally arrived in the northernmost tip of the Antarctic Peninsula and have sought shelter behind Elephant Island. Elephant Island is an important historical site because it was here that Ernst Shackelton’s party remained stranded for an extended period of time. One can only imagine the conditions under which these individuals lived. So next time we complain about the cold in Illinois, reflect upon the environmental extremes that Shackelton and his crew experienced.