SUBFOSSIL OSTRACODES REVEAL ONGOING REMEDIATION EFFORTS IN CONESUS LAKE RECREATING PRE-EUROPEAN ECOSYSTEM STATE
Two sediment cores were taken one from shallow waters in the north and south basins of Conesus Lake. Both sediment cores comprise more than 1.5 m of sediment. Based on previous studies, we estimate these sedimentary archives extend to the early eighteenth century, prior to permanent European settlement in the late eighteenth century.
Six species were observed in the sedimentary archives. Three species of Candona display large changes in relative abundance towards the top of both cores with Ca. ohioensis and Ca. elliptica declining towards the core-tops, while Ca. candida increases towards the core-tops. Two other species, Cypridoposis vidua and Darwinula stevensoni, also increase towards the core-tops, while Limnocythere verrucosa declines in the most recent sediments. Of the three species abundant in recent sediments, Ca. candida and Cy. vidua, were also elevated in the oldest sediments. Additionally, Ca. ohioensis and Ca. elliptica were present at low abundances in the oldest sediments and peak in abundance from 50 cm to 10 cm below the core-tops before declining. Thus, Ca. candida and Cy. vidua may be indicators of mesotrophic conditions, while Ca. ohioensis and Ca. elliptica may indicate eutrophic conditions. Future radiometric dating of sedimentary archives will allow more robust assignments of ostracodes as trophic indicators. Monitoring of live ostracodes can be used to indicate Conesus’s trophic state, while the return of Ca. candida and Cy. vidua to high abundance shows ongoing remediation has recreated a pre-European ecosystem state.