Distribution and Bioavailability of Trace Metals in Shallow Sediments from Grand Lake, Oklahoma.

The Tri-State Mining District (TSMD) is a historic mining area containing the Tar Creek superfund site and is the source for sediment-bound metals in Grand Lake. Despite elevated concentrations of cadmium, lead, and zinc, no evidence of sediment toxicity has been observed during previous investigations; however, these studies were limited to lake transects with mostly deep-water sediments. The purpose of this study was to assess whether TSMD-specific sediment toxicity thresholds (STTs), developed for small streams and tributaries draining the TSMD, are predictive of biological effects within the greater lake body.

Spatiotemporal analysis of microbial community dynamics during seasonal stratification events in a freshwater lake (Grand Lake, OK, USA).

Many freshwater lakes undergo seasonal stratification, where the formation of phototrophic blooms in the epilimnion and subsequent sedimentation induces hypoxia/anoxia in the thermocline and hypolimnion. This autochthonously produced biomass represents a major seasonal organic input that impacts the entire ecosystem. While the limnological aspects of this process are fairly well documented, relatively little is known regarding the microbial community response to such events, especially in the deeper anoxic layers of the water column.

Microbial communities mediating algal detritus turnover under anaerobic conditions.

Background: Algae encompass a wide array of photosynthetic organisms that are ubiquitously distributed in aquatic and terrestrial habitats. Algal species often bloom in aquatic ecosystems, providing a significant autochthonous carbon input to the deeper anoxic layers in stratified water bodies. In addition, various algal species have been touted as promising candidates for anaerobic biogas production from biomass.