Impact of hypolimnetic oxygenation on profundal macroinvertebrates in a eutrophic lake in central Alberta. I. Changes in macroinvertebrate abundance and diversity
| Autor: | E E Prepas, W P Dinsmore |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | Canadian Journal of Fisheries and Aquatic Sciences. 54:2157-2169 |
| ISSN: | 1205-7533 0706-652X |
| DOI: | 10.1139/f97-122 |
| Popis: | Hypolimnetic oxygenation from 1988 to 1991 in the north basin of Amisk Lake increased mean summer (June-August) dissolved oxygen (DO) concentrations in the deep hypolimnion (25 m) from -1 during pretreatment years (1980-1987) to 2.7 mg ·L-1 during treatment. Mean summer hypolimnetic temperatures at 25 m also increased from 6.3 (pretreatment) to 8.1°C (treatment). Profundal (15-25 m) Chironomus spp. abundance in the treated basin increased from 2000 ·m-2 from 1988 to 1991 whereas Chaoborus spp., Tubificidae, and other taxa remained uncommon at similar depths. Shannon-Weaver indices of diversity decreased as oxygenation progressed, in contrast with previous studies. Similar patterns in densities and diversity were observed in the south basin of Amisk Lake, although the increase in DO concentrations was smaller relative to the north basin. The impact of increased water temperature on macroinvertebrates appeared minor relative to the effects of increased DO concentrations. No changes in macroinvertebrate communities were noted in a nearby reference lake during the study period. Responses to hypolimnetic oxygenation in Amisk Lake differed markedly from those reported for smaller, single-basined water bodies. |
| Databáze: | OpenAIRE |
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