Professors and students in the Benthic Lab at MLML are generally interested in disturbance ecology, or how communities respond to sudden changes in their environment. In our Antarctic work, the disturbances we focus on are caused by humans. In the ASPIRE project we are examining the disturbance created by a sewage outfall in a polar ecosystem.
|At the end of an Antarctic dive, Dr. Kathy Conlan is dwarfed by the brine tubes hanging below the ice.|
The main US base in Antarctica, McMurdo Station, houses more than 1100 people during the austral summer. With people come their waste products, and until this year sewage was released into the ocean near McMurdo. This January (2003) a sewage treatment plant was completed and began operating. We are studying how Antarctic seafloor communities near the outfall will recover now that sewage is being treated.
|McMurdo Station, with Mt. Erebus, the southernmost active volcano on the planet, in the background.|
|The outfall pipe at McMurdo; you can see the pile of solids that up until this year built up at the end of the pipe. (photo courtesy of Rob Robbins).|
Stacy Kim puts on her dive gear
|We dive with scuba and surface supply systems to conduct our experiments. But there are some challenges to diving in the Antarctic, like how do you get into an ocean covered by 2 m of ice? And how do you survive in water that is -1.5 degrees C? There is an excellent support system at McMurdo Station, provided by Raytheon Polar Services Corporation under contract to the National Science Foundation. To get into the ocean, tractors tow drilling equipment over the ice, and drill 1.2 m diameter holes down 2 or more meters until they reach seawater. The ocean is colder than freshwater freezing temperature because the salt in seawater disrupts the formation of ice crystals. We use drysuits and lots of fleece clothing to keep us warm while we dive.||
John Oliver in his drysuit under the ice.
We started this study last year in the austral spring of 2002 just before the sewage treatment plant was completed. From that first season of data, we discovered that the old dump site near the sewage outfall, which used to have very high concentrations of chemical contaminants, has been partially 'capped' by the organic material from the outfall, resulting in a less toxic habitat. We return this year to see what changes have occurred in the seafloor community at the outfall after 10 months of sewage treatment and community recovery.
The seafloor at the old dump site is scattered with 55 gallon drums like this one.
Moss Landing Marine Laboratories