Letters from Antarctica

These two "letters home" describing research being done at McMurdo Station, Antarctica, were written by Drs. Jim McClintock and Chuck Amsler for the UAB Reporter, the weekly UAB newspaper for faculty, staff, and the UAB community overall.

October 23, 1997

We write this "letter home" as we sit trapped in our laboratory at McMurdo Station, Antarctica. We are unable to leave the building as the station is under Weather Condition One, which means visibility less than 100 feet and winds greater than 55 knots (it could also mean windchills colder than -100 degrees F). Why would two UAB Biology professors find themselves in this situation? We are here with support from the National Science Foundation investigating aspects of the chemical ecology of antarctic marine invertebrates and algae. Our work takes us under the sea ice to collect marine organisms which we bring back to the laboratory for experimental use.

To access different marine environments, we travel by tracked vehicles or, sometimes, by helicopters to a variety of locations in the McMurdo Sound region. By drilling or dynamiting holes through the sea ice, or by chipping into natural ice cracks, we don our drysuits and enter a spectacular underwater wonderland. Unparalleled visibility, commonly 600 or more feet, allows us spectacular vistas of a diverse and rich marine community which includes six foot sponges, giant sea spiders, fields of sea anemones, and an array of other marine animals and plants. From amongst this plethora of life we carefully select those organisms most likely to harbor chemical compounds which defend them from predators or competitors. We bring these organisms as well as their potential predators and competitors back to the laboratory where we can study the chemical interactions between them. Over our many trips to Antarctica we have discovered a number of unique chemical relationships between these organisms. In addition, working with a Natural Products Chemist, Dr. Bill Baker of the Florida Institute of Technology, we have identified a variety of novel chemical compounds. Although the focus of our work is on the ecological importance of these compounds, we also make them available for drug discovery research. For example, one of the compounds isolated from a sponge during our last trip to Antarctica shows promise as an antitumor agent.

Even though severe environmental conditions like those we are experiencing today can make the work difficult, we find this research and its implications exciting and rewarding and look forward to describing this season's results in our next letter.

Jim McClintock
Professor of Biology

Chuck Amsler
Assistant Professor of Biology

Letter Home Part II

November 15, 1997

This "letter home" comes to you within hours of our return by helicopter from a remote field camp our research group has established 75 miles across McMurdo Sound at the foothills of the Transantarctic Mountains. Situated at the base of massive cliffs of granite, and aptly named Granite Harbor, our encampment of tents sits on six feet of sea-ice, providing ready access via snowmobile to numerous ice cracks. Through these cracks we dive to collect sponges, soft corals, mollusks and algae for our ongoing studies of their chemical ecology.

Jim and Chuck at Granite Harbor
Since we last wrote to you describing our NSF-sponsored studies of the defensive properties and pharmacological potential of secondary metabolites in antarctic marine organisms we have been able to write several new chapters of our developing story.

First, we have made substantial progress in our pursuit of novel ecologically-relevant metabolites, especially with respect to their antipredator role. For example, we have found that in Antarctica sponges are extremely vulnerable to predation by sea stars, and thus, sponges have evolved a suite of metabolites that prevent attack by this predator. Interestingly, we have just discovered that some of these compounds inhibit the digestive enzymes of the spongivorous sea stars. Another role for such compounds we have discovered this field season is in the inhibition of overgrowth by microscopic algae. This is a particularly important problem in antarctic waters where dense blooms of these algae occur seasonally. We have also been examining a relationship between sea urchins and macroscopic algae. These macroalgae are chemically defended from being eaten by sea urchins but the sea urchins choose to cover themselves with plants which have been torn loose, thereby preventing the sea urchins from being captured and subsequently consumed by their major predator, a large sea anemone. The algae benefit in turn, being held by sea urchins at depths where they can still photosynthesize and reproduce. This is an intricate and complex form of mutualism.

As much as we look forward to our impending return to UAB we are very excited by the scientific discoveries we have made during this trip as well as by the stark beauty of our antarctic environs. As we helicoptered back from Granite Harbor this morning along the edge of the sea ice, we followed a pod of 30 killer whales hunting for penguins in the shadows of volcanic Mount Erebus. Such memories will accompany us back to UAB where we will continue studies of chemical relationships begun here in Antarctica.

Jim McClintock
Chuck Amsler

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