3 Paleolimnological Records of Landscape Change

Sunday, 18 March 2018
8:00 AM - 12:00 PM
Emerald Ballroom I

TEASING OUT ANTHROPOGENIC FROM NATURAL PERTURBATION ON THE LAKE GEORGE ECOSYSTEM – EVIDENCE FROM NON-POLLEN PALYNOMORPHS IN “POLLEN SLIDES”

Paper number: 3-7
Program: Theme Sessions
Time: 9:45 AM – 10:05 AM

Authors

Abstract

Water quality and recovery efforts are being studied by the Jefferson Project at Lake George, a partnership between Rensselaer Polytechnic Institute, IBM, and the FUND for Lake George. Algal and other non-pollen palynomorphs (NPP) were compared with assemblages of better-understood paleolimnological proxies (testate amoebae and diatoms; Kornecki et al., in prep.) in 33 lakebed samples. This illustrated the utility of these organic-walled microfossils in “pollen slides” as biomonitors, particularly of human impact (McCarthy et al., in press). Green algae typically dominate palynological assemblages in the southern basin, with relatively abundant Coelastrum reticulatum and various Pediastrum and Cosmarium spp. recording mesotrophic – eutrophic conditions near population centers at Lake George Village and Bolton Landing. In contrast, lakebed sediments from the northern basin (surrounded by Forever Wild forest in the Adirondack Park) are typically dominated by cysts of dinoflagellates, especially Parvodinium inconspicuum and Fusiperidinium wisconsinense. Assemblages at the northernmost sites resemble those in the south basin, however, with abundant green algal palynomorphs recording anthropogenic impact from the town of Ticonderoga.

Microfossils in sediment archives record long-term environmental trends that can be compared to changes in water quality (e.g., salt and nutrient loading) measured since 1980 (Boylen et al., 2014), allowing the natural signature to be separated from the anthropogenic impact. Increased abundances of green algal palynomorphs in ragweed pollen-rich sediments confirm the impact of humans over the past few centuries, particularly in the southern basin.

References cited:

Boylen, C.W., L.W. Eichler, M.W. Swinton, S.A. Nierzwicki-Bauer, I.A. Hannoun and J.W. Short. 2014. The State of the Lake: Thirty Years of Water Quality Monitoring on Lake George, New York, 1980-2009. 72 pp. http://fundforlakegeorge.org/StateoftheLake.

Kornecki et al. in prep. Calibrating paleo-biomonitors in Lake George, NY sediments with modern geochemical and limnological measurements. Manuscript intended for Journal of Paleolimnology

McCarthy et al. in press. Algal palynomorphs as proxies of human impact on freshwater resources in the Great Lakes region. Anthropocene ANCENE158

Geological Society of America Abstracts with Programs. Vol. 50, No. 2

doi: 10.1130/abs/2018NE-311158

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