237 Paleoclimatology/Paleooceanography

Tuesday, 21 October 2014
1:00 PM - 5:00 PM
223/224

BIOCHEMICAL, GEOCHEMICAL, AND PALEOECOLOGICAL ANALYSES OF A NEWLY DISCOVERED PEATLAND ON THE WESTERN ANTARCTIC PENINSULA

Paper number: 237-13
Program: Technical Sessions
Time: 4:00 PM – 4:15 PM

Authors

Abstract

Peat-forming ecosystems along the West Antarctic Peninsula (WAP) have been receiving lots of attention from scientists and the media recently. These moss-dominated terrestrial ecosystems can be cored and potentially used as high-resolution, high-quality archives for late-Holocene climatic conditions, thereby providing new insights on the southern hemisphere recent climate history. So far, these Antarctic studies have focused on ‘dry’ permafrost mossbanks. However, during our field expedition in February 2014, we discovered two ‘wet’ peatlands that had formed in rocky depressions near Vernadsky Station (65°14’ S, 64°15’ W). The similarity between these peatlands and those found in the northern hemisphere is striking, and the rarity of these systems along the WAP is intriguing. These peatlands may represent a transition from aerobic mossbanks to anaerobic/waterlogged peatlands, which would be an important ecosystem transformation along the WAP that could be promoted in a warmer and wetter climate.

We present a high-resolution, multi-proxy record of ecosystem development and environmental conditions for Rasmussen peatland. To our knowledge, this peatland is the very first one to be described and analyzed along the WAP. Carbon isotope measurements and biochemical analyses (e.g., amino acids, carbohydrates, lignin phenols) are being performed, in addition to routine analyses including carbon and nitrogen content, organic and inorganic matter content, and plant macrofossil analysis. The peatland has a high organic matter content (> 90% dry weight) and distinct changes in peat properties were visually described on the basis of color and texture. Preliminary biochemical results are promising, as the signature of each Antarctic plant functional type (e.g., algae, vascular, moss, fungi, lichen) can be distinguished. These modern plant signatures will be used to reconstruct past vegetation assemblages downcore. Decomposition indicators such as carbohydrate yields, acid:aldehyde ratios of lignin phenols, and hydroxyproline yields will be determined to better understand the extent of peat decay that has occurred at this site, particularly in relation to the recent warming. Overall, this study of a newly discovered peatland offers insight regarding Antarctic paleoclimate using a new approach.