Research Seminar Series: Assessing Chemical and Biological Recovery From Acid Deposition in Montane Vermont Lakes

Speakers: Sydney Diamond, MS graduate, and Mindy Morales-Williams, assistant professor, both of the University of Vermont Rubenstein School of Environment and Natural Resources

Register for the online Zoom option:  https://us06web.zoom.us/webinar/register/WN_PlYBF6UZT-uj5ZPM4kzrdQ 
To request a disability-related accommodation to participate in any of these programs, please contact Lake Champlain Sea Grant / Julianna White at 802-777-7017 or seagrant [at] uvm.edu (subject: Research%20seminar)  no later than three weeks before your chosen date so we can assist you.

This September 2021 seminar was recorded and can be viewed online.

Vermont’s inland lakes are changing rapidly in response to anthropogenic disturbance pressures. While changes in water chemistry are well documented across the state, the biological response of primary producer communities to these shifts remains poorly understood. This project investigated the response of phytoplankton communities to the interacting effects of recovery from acidification and climate change in montane lakes. Researchers analyzed long-term monitoring and meteorological data in four of Vermont’s acid-impaired lakes and found that as pH and acid-neutralizing capacity has increased, so have concentrations of dissolved organic carbon (DOC) in most lakes.

To assess the biological response to these processes, they collected spring, summer, and fall phytoplankton samples in four focus ponds representing a gradient of DOC concentrations (Beaver, Big Mud, Bourn, Haystack) during ice-free seasons of 2018 and 2019. In addition to this, they reconstructed paleo-chemistry and diatom community composition in Beaver Pond from approximately 1836 to the present. Phytoplankton community composition varied seasonally within and between lakes, but was generally dominated by chrysophytes, chlorophytes, and diatoms. They found low concentrations of potentially bloom-forming cyanobacteria at all sites (Pseudanabaena spp., Microcystis spp.), but did not observe bloom events during the study period. Paleolimnological analyses indicate that the largest shift in diatom community composition has occurred over the last 30 years in Beaver Pond, but that modern assemblages are different than those present pre-acidification, suggesting a new ecological trajectory as aquatic systems face increased climate pressures.

Participants should expect approximately 30 minutes of presentation, which will be recorded, followed by a facilitated, 30-minute Q&A period.

This seminar is part of the Lake Champlain Sea Grant Seminar Series. This research effort received monetary support from the Vermont Water Resources and Lake Studies Center.