POTENTIAL INFLUENCE OF LAKE MORPHOMETRY ON PALEOPRODUCTIVITY PATTERNS IN LAKES UNDER SIMILAR CLIMATE CHANGE CONDITIONS IN THE ADIRONDACK MOUNTAINS OF NEW YORK

Kling et al. (2000) reported geographically proximal lakes subjected to similar climate change conditions responded similarly, and thus exhibited synchrony. Kanfoush (2013) reported changes in diatoms in 4^th Lake of the Fulton Chain of Lakes in the Adirondacks strongly correlated with changes in northern hemisphere temperature (NH-T), atmospheric CO₂, and solar irradiance. Spado (2008), however, found other lakes in the Fulton Chain, which are both proximate and hydrologically connected, did not exhibit synchrony in changes in their physical and chemical sediment characteristics, due to differences in individual lake morphometry. We hypothesize the lakes’ paleoproductivity also responded asynchronously. Old Forge Pond, 2^nd Lake, and 3^rd Lake of the Fulton Chain were analyzed in this study. Although semi-connected and subjected to similar climate, these lakes have varied morphometry. Cores recovered in 2006 were sampled at 1-cm intervals, ²¹⁰Pb dated, and ≥400 diatom valves counted in each at 400x magnification via DIC microscopy.

Diatom concentration and accumulation in Old Forge Pond and 3^rd Lake did not appear to respond significantly to changes in NH-T, atmospheric CO₂, or solar irradiance. However, in 2^nd Lake diatom concentration correlates with NH-T and atmospheric CO₂ (R = 0.28 and 0.66, respectively) and diatom accumulation with NH-T, CO₂, and irradiance (R = 0.58, 0.61, and 0.50, respectively). Strong correlations with these parameters are also observed for 2^nd Lake % organics (R = 0.84, 0.91, and 0.56) and organic mass (g) (R = 0.54, 0.67, and 0.30) Thus, it appears biological productivity of these semi-connected lakes does not respond to climate forcing in a similar manner. Alternatively, some lakes may respond more substantially to land use changes. An understanding of potential variability of individual lake response to similar climate and other environmental forcing is useful to local land-use planners and policy-makers as they seek to mitigate impacts.