HR: 0800h
AN: B31A-0062    [Abstracts]
TI: Compound-Specific Stable Isotopes of Organic Compounds From Lake Sediments Track Recent Environmental Changes in an Alpine Ecosystem, Rocky Mountain National Park, Colorado (United States of America)
AU: * Enders, S K
EM: sara.enders@yale.edu
AF: Yale School of Forestry & Environmental Studies, 210 Prospect Street, New Haven, CT 06511, United States
AU: * Enders, S K
EM: sara.enders@yale.edu
AF: Department of Geology & Geophysics, Yale University, P.O. Box 208109, New Haven, CT 06520, United States
AU: Pagani, M
EM: mark.pagani@yale.edu
AF: Department of Geology & Geophysics, Yale University, P.O. Box 208109, New Haven, CT 06520, United States
AU: Pantoja, S
EM: spantoja@udec.cl
AF: Department of Oceanography and FONDAP COPAS Center, Universidad de Concepción, P.O. Box 160-C, Concepción, 3349001, Chile
AU: Baron, J S
EM: jill@nrel.colostate.edu
AF: U.S. Geological Survey, Natural Resource Ecology Laboratory, Colorado State University, NESB, B225, Fort Collins, CO 80523, United States
AU: Wolfe, A P
EM: awolfe@ualberta.ca
AF: Department of Earth and Atmospheric Sciences, University of Alberta, Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, T6G 2E3, Canada
AU: Pedentchouk, N
EM: nikolai@ucalgary.ca
AF: Department of Geology & Geophysics, Yale University, P.O. Box 208109, New Haven, CT 06520, United States
AU: Pedentchouk, N
EM: nikolai@ucalgary.ca
AF: Department of Geoscience, University of Calgary, 844 Campus Place, NW, Calgary, AB T2N 1N4, Canada
AU: Nuñez, L
EM: lnunez@udec.cl
AF: Department of Oceanography and FONDAP COPAS Center, Universidad de Concepción, P.O. Box 160-C, Concepción, 3349001, Chile
AB: Sediments from high altitude lakes in the North American Cordillera reveal rapid changes in both the composition of diatom communities and bulk organic δ¹⁵N over the past c. 60 years. In this study, compound- specific nitrogen, carbon, and hydrogen isotope records from Sky Pond, an alpine lake in Rocky Mountain National Park (Colorado, United States of America), were used to identify the factors contributing to ecological change. Our results from the nitrogen isotopic compositions of purified algal chlorins indicate that the magnitude of isotopic change is larger than implied from bulk organic δ¹⁵N, and support a substantial shift in nitrogen (N)-cycling in the region. Temporal changes in the growth characteristics of lichen surrounding Sky Pond, as well as a -60‰ excursion in δD values of algal-derived palmitic acid, are coincident with changes in N-cycling, indicating alterations in catchment hydrology and nutrient delivery. The confluence of these trends is attributed to an increase in anthropogenic N deposition caused by both expansion anthropogenic influences and temporal changes in regional hydrology associated with snow, glacier, and permafrost melt.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0454 Isotopic composition and chemistry (1041, 4870)
DE: 0458 Limnology (1845, 4239, 4942)
DE: 0469 Nitrogen cycling
DE: 0475 Permafrost, cryosphere, and high-latitude processes (0702, 0716)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting