Abstract:

Water temperature (°C), pH, dissolved oxygen concentration (mg/l) and the community structure of the macrobenthos of a small southeast Texas sand-pit (Barry's) lake were studied from June 1995 to February 1996, which covered climatic extremes. The lake was a warm monomictic lake and no anoxic conditions were observed at any depth during the entire study period. A total of 50 taxa and 5614 individuals of macrobenthos were collected. The dominant organisms were Chaoborus punctipennis (Say), Limnodrilus hoffmeisteri (Claparede), and Dero obtusa (Udekem). The only established populations at 6.5 m were Chaoborus punctipennis, Limnodrilus hoffmeisteri, and Chironomus sp. Species diversity ranged from 0.9 to 3.9 and generally decreased with depth. The number of individuals increased with depth, while the species and species diversity decreased with depth.

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