Bod dynamics in small eutrophic lakes in relation to artificial mixing

Abstract

Seasonal and annual variation in the biochemical oxygen demand of the water column (WBOD) and the sediment (SBOD) are described for two small central Iowa lakes based on sampling over 57 consecutive months, 1977–82. A correlation analysis was done to determine the relationship between WBOD and SBOD to 15 physical and chemical variables using composite values for the whole lake and for the top, middle and bottom-most strata on each sampling date. The best single variable model for predicting volume-weighted WBOD was mean lake chlorophyll a concentration: WBOD = 1.79 + 0.032 (chlorophyll a). There were no significant correlations between SBOD and any of 15 environmental variables, but in the control lake, not artificially destratified, SBOD and chlorophyll a (−) and ammonia (+) showed significant correlations. Artificial destratification increased the vertical distribution of oxygen and chlorophyll a, reduced peaks of algal blooms, increased near-bottom water temperature and oxygen concentration, and reduced SBOD and ammonia. © 1986 Taylor and Francis Group, LLC.