||Effects of Fluorene on Microcosms Developed from Four Natural Communities (Journal Version).
Stay, F. S. ;
Katko, A. ;
Rohm, C. M. ;
Fix, M. A. ;
Larsen, D. P. ;
||Environmental Research Lab.-Duluth, MN. ;Northrop Services, Inc., Corvallis, OR.
Aquatic microbiology ;
Aquatic ecosystems ;
Water pollution effects(Animals) ;
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Ecosystem-level responses were examined in microcosms developed from four different natural plankton communities and exposed to nominal concentrations of 0.12, 0.50, 2.0, 5.0 and 10.0 mg/L fluorene. The lowest observed effect level (LOEL) for dark respiration was 0.12 mg/L fluorene in three of the four communities during the first 14 d; in the fourth community, it was 5.0 mg/L. The LOEL of the net productivity/respiration ratio was 0.12 mg/L in all four communities. These results suggest that the responses of these microcosms were not completely independent of their source communities. The sensitivities or LOEL values from these microcosm experiments were as low as those reported for chronic bioassays of the three most sensitive of seven standard test organisms. Comparisons between the responses of these microcosms and those reported for experimental ponds exposed to the same concentrations of fluorene suggest that these microcosms accurately reflect the types of changes and concentrations that cause change in pond ecosystems.