TOWARD UNDERSTANDING DRIVERS AND CONTROLS OF HOLOCENE OXYGEN ISOTOPIC SHIFTS OF WATER AND PEAT CELLULOSE ON THE KENAI PENINSULA, ALASKA

Oxygen isotope proxy records from lakes, ice cores, and more recently peatlands in Alaska have linked isotopic shifts to modes of climate variability during the Holocene. However, the orographically complex coastline of southcentral Alaska presents additional challenges for interpreting these records in regions such as the Kenai Peninsula, where regional expression of large-scale circulation changes may differ. The degree to which records from lakes and ice cores can be compared to records from peatlands also remains largely unexplored. To address these questions and better understand the controls on peat cellulose oxygen isotope variability in Alaskan, we collected modern moss and water samples across a hydrologic and orographic transect spanning from the relatively dry western Kenai lowlands (leeward) to the wet eastern Kenai Mountains (windward). First, we are evaluating interspecific variability across a local, lateral (~50 m) hydrologic gradient (from submerged to ~30 cm above the water table), where cellulose was extracted from ~10 different moss species, bulk moss, and moss stems and leaves for comparison with the isotopic composition of source water. Second, new insights from the modern study will be used to assess down-core isotopic variations and better constrain interpretation of Holocene peat cellulose isotope and macrofossil records that are currently being developed from both the leeward and windward sides of the Kenai Mountains.