Traceable Climate Change and its Impact on the Finger Lakes region of New York: Early Interpretations and Potential Consequences on Long-Term Biogeochemical Cycles.

Abstract

Climate change impacts on the Northeastern United States are expected to make the region more temperate overtime, with warmer winters, less total snowfall, and more rainfall. While this muting of extreme colds and snow is expected to make the region more temperate, the shift from decreasing snowfall to increasing rainfall has led to noticeable changes in hydro-biogeochemical dynamics in regional watersheds. Within this region lies the Finger Lakes, a series of 11 lakes carved out during the last glacial maximum. These lakes are particularly susceptible to increased rainfall amounts, particularly extreme events, due to the extensive gorge network and sharp topography of the landscape which favors enhanced soil erosion and nutrient fluxes into the lakes. The Finger Lakes have an average residence time of 5 to 7 years (the maximum being 23 years), which provides a unique opportunity to better understand how changes in precipitation regimes affect this dynamic landscape. This study focuses on hydrogeochemical monitoring of the Finger Lakes, and a local tributary that feeds into Cayuga Lake to better understand the sensitivities of the lakes to increased rainfall, and smoke events lasting in the area.

This study presents a daily to weekly dataset focusing on hydrogen and oxygen stable isotopes as well as common anions and cations of rainwater, snow waters, lakes and tributaries within the Finger Lakes region over the past year. We show that the Hydrogen (δ²H) and oxygen (δ¹⁸O) stable isotope composition of the Finger Lakes (11 lakes total, n=22) has shown enrichment between the early 1990s and 2022 (Δ¹⁸O_22-91 = 1.13 ± 0.91‰, Δ²H_22-91 = 7.18 ± 5.16 ‰). This enrichment is accompanied with a stark increase in annual (1% to 3%) and winter (2% to 7%) rainfall while simultaneously exhibiting a decrease in annual (-10% to -1%) and winter (-9% to -0.2%) snowfall across the Finger Lake region. Complementing long term climate signals, we also show that on shorter timescales tributaries that feed into Cayuga lake (the 2nd largest Finger Lake) are able to significantly impact water quality. A notable example is the elevated frequency of harmful algal blooms in the Finger Lakes since 2014. As the Finger Lakes evolve into a rain dominated system, solute loading from streams of both biogenic and geogenic origin can be expected to increase drastically.