Hypolimnetic Aeration a.nd Zooplankton Distribution: A Possible Limitation to the Restoration of Cold-Water Fish Production
Hypolimnetic aeration of a 1.23-ha eutrophic kettle lake during two consecutive summers increased [Qzl to more than 4m@L in the hypolimnion for extended periods. This improvement did not lead to the expected development of crustacean populations in the previously anoxic, zooplankton-deficient hypo....
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.514.1643 http://www.phys.ocean.dal.ca/~taggart/Publications/Taggart_CJFAS41-1_1984.pdf |
| Summary: | Hypolimnetic aeration of a 1.23-ha eutrophic kettle lake during two consecutive summers increased [Qzl to more than 4m@L in the hypolimnion for extended periods. This improvement did not lead to the expected development of crustacean populations in the previously anoxic, zooplankton-deficient hypo. Bimnion. The rotifer Fdinia longiseta was the only zooplankter present, as isolated populations, in both the epilimnion and hypolimnion during summer. Eighty percent of the summer zooplankton community occurred exclusively in the epilimnion, and this was related to the development of an anoxic and toxic metalimnion that restricted migration from the epilimnion to the hypolimnion. Confinement of the zoo-plankton to the epilimnion coupled with predation by fathead minnows (Pirnephales promelas) appeared to be responsible for the change in the zooplankton community from large cladocerans and copepods to smaller species. This study suggests that hypolimnetic aeration as a means of restoring or enhancing the production of cold-water fish may be thwarted by the development of a stable anoxic and toxic meta-limnion that precludes the development of the zooplankton food resource. L'aeration hypolimnetique d'une marmite eutrophe d'une superficie de I,23ha durant deux etes consecu-tifs eut pour effet d'augmenter [Q2] a plus de 4mgL dans Ifhypolimnion pendant de longues periodes. Cette amelioration n'a pas cause le d6veloppement anticipe des populations de crustaces dans un |
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