The limnology of Lake Clark, Alaska

Abstract

This study gathered baseline limnological data to investigate the thermal structure, water quality, phytoplankton, and zooplankton of Lake Clark, Alaska. Results indicate Lake Clark is oligotrophic and mixes biannually, but stratification is weak and thermoclines are deep. Longitudinal gradients were seen in measurements of temperature, suspended solids, turbidity, light penetration, algal biomass, and zooplankton density. Wind and tributary inputs determine the thermal regime. Glacially-influenced tributaries drive turbidity and light gradients by introducing suspended solids to the inlet end of the lake. Suspended solids likely create the algal biomass gradient by limiting the light available for photosynthesis in the inlet basin. Algal biomass and turbidity gradients may interact to create an area of high productivity and low predation risk, causing high zooplankton concentrations in the central basin. Oxygen supersaturation was discovered in the hypolimnion but remains unexplained. Because tributaries are glacially influenced, Lake Clark could be sensitive to global warming.