Assemblages of diatoms, microscopic golden algae with siliceous frustules, have been used to assess the trophic states of lakes, ponds and bays. The trophic history of Sodus Bay, Wayne County, New York was investigated through identification and enumeration of diatom valves preserved in a 1-meter sediment core extracted from the Bay. Total phosphorus analysis also was performed. Removed with a KB corer in May 1998, the core was sectioned into 1 cm samples, which were freeze dried and 210Pb dated. Coverslips were prepared using Battarbee trays. Diatom valves, some as old as 338 years, were examined in transects of mounted coverslips. Phosphorus concentrations of digested samples were determined using a Technicon Auto-analyzer. Phosphorus concentrations were highest from 1795 to 1910 and in 1998. The Lake Trophic Status Index suggests that mesotrophic conditions existed from 1660 to 1681 and that eutrophic conditions developed in the ensuing centuries. These changes are consistent with settlement and the establishment of agriculture and shipping in the watershed.
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