INVESTIGATING THE IMPACT OF INVASIVE MUSSELS ON ECOSYSTEM DYNAMICS IN CONESUS LAKE

This study explores how invasive mussels influence ecosystem dynamics in Conesus Lake. Conesus Lake, the westernmost of New York’s Finger Lakes, has undergone significant environmental changes, experiencing cultural eutrophication and recent remediation. Despite improvements, the lake faces periodic hypoxia, harmful cyanoalgal blooms, whiting events, and ongoing challenges from invasive species such as Dreissena polymorpha and Dreissena bugensis. By examining invasive mussel body size and morphology over time, this study aims to understand the ecological and environmental impacts of invasives using lake sediment archives. Two sediment cores over 150 cm in length were collected from the south basin of Conesus Lake. The cores were split, imaged, and analyzed using a Geotek multi-sensor core logger. Sub-fossilized shelly material was sampled at the centimeter level and mussels were identified to the species level. Body size measurements including length, height, and dorsal curvature were collected. A total of 50 mussels were assessed from four distinct horizons encompassing contemporary sediments to first appearance of invasive mussels (mid-1990’s). D. polymorpha valves displayed a mean length of 6.6 mm, mean height of 3.3 mm, mean dorsal angle curvature of 54°, and mean length to height (L/H) ratio of 1.8. D. bugensis valve mean length was 2 mm, a mean height of 1.2 mm, mean dorsal angle curvature of 57°, and a mean L/H ratio of 1.6. Both D. polymorpha and D. bugensis showed a strong correlation between valve length and height (r²= 0.994 and r²= 0.9904, respectively). Small D. polymorpha displayed high dorsal angle curvature, however, larger valves showed reduced dorsal angle curvature. D. bugensis dorsal angle curvatures revealed no correlation with body size, however most valves had greater dorsal angle curvature than D. polymorpha. In comparison to contemporary D. polymorpha, the mussel body size was greater during its first appearances in the lake, starting around 63 cm in depth. D. bugensis exhibited consistent body size near the core-tops, indicating it is recently established in Conesus Lake. In future work, we plan to incorporate DNA analysis to confirm species identification and validate morphological identification to better determine timing of mussel invasives in the Conesus Lake ecosystem.