FAYETTEVILLE GREEN LAKE DENSITY DATA REVEALS LOCAL IMPLICATIONS OF CLIMATE CHANGE

Fayetteville Green Lake is a meromictic lake with anoxic bottom waters, preserving a pristine climate record in sediments with negligible bioturbation. While many temperate bodies of water undergo seasonal stratification, Green Lake’s unique chemistry results in permanent stratification primarily through differences in salinity rather than temperature. However, with a TDS ranging only from 2,000 - 2,500 mg/L, the influence of temperature could eclipse the influence of salinity if bottom water temperatures rise due to climate change.

While the lake has been stratified for at least the last 100 years, some researchers have questioned the stability of this meromixis because of the delicate balance between the effects of temperature and salinity on density. To assess the permanence of the stratification, we collected samples from the less-dense surface water and the more-dense bottom water. We calibrated pycnometers with distilled water, and then measured small changes in density across a range of temperatures. By directly measuring the densities of these different parcels of water (less saline surface waters vs. more saline bottom water), and exploring how they react to changes in temperature we are better able to predict the conditions that could destabilize the lake.

While most studies focus on the large-scale ecological and societal impacts of climate change, the effects on local ecosystems have largely been overlooked. Understanding the effects that climate change has on this lake may also help us resolve previously unexplained events preserved in the rock record. We hope that our work will start a new leg of research into smaller ecosystems and the implications that climate change may have on those systems.