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Algal nutrient enrichment bioassay were conducted between May, 1975 and August 1978 using water samples collected from Chautauqua Lake, New York. Photosynthetic fixation rates of natural phytoplankton assemblages were enhanced by additions of phosphorous and nitrogen although enrichment with other nutrients had no significant stimulatory effect on algal photosynthesis. Whereas phosphorus stimulated in spring and early summer, both nitrogen and phosphorus stimulated in spring and early summers, both nitrogen and phosphorous enhanced photosynthesis in mid-summer and fall. Relative to the effect of phosphorus enrichment, enhancement of photosynthesis by nitrogen during the summer and fall was highest in the northern part of the lake. During the period of ice cover, photosynthesis did not appear to be limited by nutrients in that nutrient additions (P, N, Si, C, Fe, trace metals) did not enhance fixation rates. Observed temporal fluctuations in the response of the algae to P and N correlated with changes in the lake water N:P ratios as well as with temporal changes in dissolved orthophosphate and nitrate-nitrite nitrogen. The N:P ratio decreased drastically in the summer and remained at ca. 10 or less through mid-fall, suggesting that N concentrations were inadequate for the N-fixing phytoplankton. Studies over 3 yr indicate that states of P and N limitation undergo time-space fluctuations that occur in a cyclic pattern in the surface waters of Chautauqua Lake. [ABSTRACT FROM AUTHOR]

The article presents a study which evaluates the toxicity of the Chautauqua Lake bridge runoff to young-of-the-year (YOY) bluegill sunfish. The study used 12-d bioassays and measured the water temperature by a glass mercury thermometer. Results show that all bioassays had similar temperatures, but each bioassay had a different alkalinity and conductivity between dilutions.