Distribution and long-term historical changes of zooplankton assemblages in lake manzala (south mediterranean sea, egypt)
The northern lakes of Egypt have always acted as a buffer zone between the drainage system in the Nile Delta and the Mediterranean Sea. Most of these lakes are exposed to high inputs of industrial and domestic wastewater as well as agricultural drainage water, like Lake Manzala, which influence the living organisms on the long run. Samples of zooplankton were collected monthly from ten stations among Lake Manzala showing the different microhabitat of the lake. A one year monitoring has been carried out. Lake Manzala has been changed from marine ecosystem to eutrophic, nearly, freshwater system with the dominance of rotifers (cal ~ 97%). Twenty newly recorded zooplankton taxa were found for the first time in the lake during the study, while thirteen taxa disappeared from the lake in the last fifty years due to these changes. The apparent species turnover rate in the lake increased from 3.26%/year during 60's-80's to 10.29%/year in 00's-03's. Zooplankton abundance was high in northern stations compared with other stations with high densities during March and April. The outlets between the lake and the sea should be more effective to increase the alteration of the lake water with the sea leading to renewal the lake water and decreases the pollution effect on the lake ecosystem.
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| Format: | Journal Contribution biblioteca |
| Language: | English |
| Published: |
National Institute of Oceanography and Fisheries, Egypt
2007
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| Subjects: | Field Study, Zooplankton, |
| Online Access: | http://hdl.handle.net/1834/1901 |
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| Summary: | The northern lakes of Egypt have always acted as a buffer zone between the drainage system in the Nile Delta and the Mediterranean Sea. Most of these lakes are exposed to high inputs of industrial and domestic wastewater as well as agricultural drainage water, like Lake Manzala, which influence the living organisms on the long run. Samples of zooplankton were collected monthly from ten stations among Lake Manzala showing the different microhabitat of the lake. A one year monitoring has been carried out. Lake Manzala has been changed from marine ecosystem to eutrophic, nearly, freshwater system with the dominance of rotifers (cal ~ 97%). Twenty newly recorded zooplankton taxa were found for the first time in the lake during the study, while thirteen taxa disappeared from the lake in the last fifty years due to these changes. The apparent species turnover rate in the lake increased from 3.26%/year during 60's-80's to 10.29%/year in 00's-03's. Zooplankton abundance was high in northern stations compared with other stations with high densities during March and April. The outlets between the lake and the sea should be more effective to increase the alteration of the lake water with the sea leading to renewal the lake water and decreases the pollution effect on the lake ecosystem. |
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