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Effects of fluorene on microcosms developed from four natural communities
Author(s) -
Stay Frank S.,
Katko Albert,
Rohm Christina M.,
Fix Melissa A.,
Larsen David P.
Publication year - 1988
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620070805
Subject(s) - microcosm , ecosystem , fluorene , environmental chemistry , ecology , aquatic ecosystem , biology , environmental science , chemistry , zoology , organic chemistry , polymer
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, a polynuclear aromatic hydrocarbon. The lowest observed ( p < 0.05) effect level (LOEL) for dark respiration (R ni ) was 0.12 mg/L fluorene in three of the four communities during the first 14 d. The LOEL for R ni in the fourth community was 5.0 mg/L. The LOEL of the net productivity/respiration ratio (P n /R ni ) 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. However, slight but significant changes in the ecosystem‐level variables gave no indication of the almost complete elimination of some zooplankton populations at 5.0 and 10.0 mg/L in the ponds and at 2.0, 5.0 and 10.0 mg/L in the microcosms. This lack of correspondence between population‐ and ecosystem‐level measurements suggests that test measurements made at one hierarchical level of organization may not always be appropriate for estimating effects at other levels.