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Ross Island, Antarctica is the most southern location that can be ice free during some of the year. Early explorers seeking the south pole frequently used this island as a base camp as they could reach it by ship. The sea ice grows seasonally and fluctuates year to year. Some years the ice will break out completely while other years it may only make a modest retreat. Typically, in January the sea ice edge is about 40 km north of McMurdo. A variety of macrobiota are present at the ice edge, including orcas and minke whales, penguins, and seals. The sea ice edge presents an interesting environment for UV photobiology in that it is the last direct sunlight microbial plankton are exposed to before moving further south under the ice edge. The predominant currents generally travel south down the western side of McMurdo Sound while water moves out from under the ice at the eastern edge. The current patterns permit an interesting investigation of the effects of sunlight on the two potentially different communities flowing under the ice where they have presumably been exposed to UV and those organisms moving out from under the ice where they have had little exposure.
Light measurements, plankton tows, water samples, and ice cores were collected at the ice edge to examine the effects solar UV could have in an open water environment. The primary objective of many experiments conducted at the sea ice edge was to examine the relative differences in photosensitivity of organisms at different locations along the ice edge and in relation to the predominant currents.
Working at the ice edge requires safety ropes and close cooperation between participants. |
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A Royal New Zealand Air Force helicopter provides close support while at the edge. The RNZAF and PHI, Inc., an NSF contractor, provide helicopter transport to many study sites. |
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