PARENT SESSION
Friday, August 11, 8:00-10:30 am
Poster Session 26 - Latebreaking and newsworthy posters
Exhibit Hall, Ballroom Level, Cook Convention Center

Soil carbon analysis in the Antarctic Peninsula.

Rios, Roxanne^*,1, Klopatek, Jeffrey¹, ¹ Arizona State University, Tempe, Az

ABSTRACT- The Antarctic Peninsula has experienced significant warming over the last few decades, with a MAT increase of 2°C since 1945. The warming has resulted in the receding of glaciers, exposing new areas to potential plant colonization and subsequent soil development. Increases in temperature can enhance carbon sequestration through plant establishment and productivity, but may also increase decomposition of existing carbon stores. This research examined soils underlying simple plant communities near Palmer Station, a U.S. research facility, located on the Antarctic Peninsula. Plant communities were composed of Dechampsia antarctica (Antarctic hair grass), Colobanthus quitensis (pearlwart), and assorted bryophytes. After an initial visit to the site (Biscoe Point), we proposed three hypotheses that were tested through sampling soils and analyzing them for carbon, nitrogen, and ¹⁵N. First, we hypothesized the soils would be poorly developed with low organic matter, given the climate and scarcity of flora. Second, that seabirds were the dominant source of soil nitrogen for the plant communities. And third, that the presence of only Antarctic hair grass in old penguin rookeries was due to a difference in soil N, with the grass species having a selective advantage over the pearlwart. Although plant community development was very patchy, some areas showed significant peat accumulation and soil profile development, discounting the first hypothesis. All soils sampled showed significant enrichment of ¹⁵N indicating that seabirds were the source of N. However, compared to temperate soils, these soils showed a pattern reversal in concentration, with ¹⁵N levels greater in the upper layers of the soil profile. There were no significant differences in C, N, or ¹⁵N concentrations of the soils in the old rookeries or the uninhabited plant communities, indicating some other reason, perhaps disturbance, for the absence of pearlwart. Finally, laboratory analyses of the soils showed the majority of soil C to be in the active and slow pools, indicating a potential loss with an increase in temperature.

Key words: soil ecology, soil carbon and nitrogen, Antarctic Peninsula