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Role Of Hydrology, Nutrients And Fish Predation In Determining The Ecology Of A System Of Shallow Lakes

In this study, the hydrology and physical, chemical and biological variables of a shallow lake system including the Lakes Mogan and Eymir between 1997-2005 were evaluated.
In Lake Eymir, a biomanipulation study was conducted between August, 1998 &ndash / December, 1999. Upon biomanipulation, Lake Eymir shifted to clearwater state with submerged vegetation domination during 2000-2003. However, in 2004, the lake shifted back to algae-dominated turbid state since the buffer mechanisms provided by submerged plants were absent. In the summer of 2005, fish kills were observed due to algal bloom. However, due to increasing hydraulic residence time in the lake, internal processes became more important for nutrients.
Lake Mogan faces seasonal and interannual water level fluctuations. During the low water levels experienced in 2001 and 2005, which coincided with the high hydraulic residence times, the in-lake phosphorus amount was controlled by internal

processes rather than external loading. Moreover, results revealed that hydrology and submerged plants were important in the ecology of Lake Mogan.
Furthermore, the relationship between the phytoplankton, zooplankton and the environment in Lakes Eymir and Mogan, which was predicted via Canonical Corresponding Analysis, revealed that nutrients and water transparency were both important for plankton communities. Both the top-down and bottom up effects were valid in Lake Eymir, while only the bottom-up effect and submerged plants were important for Lake Mogan.
Finally, the present study provided a good example for the submerged plant dominated clearwater state triggered by biomanipulation, and the impact of hydrology on the ecology of shallow lakes.

Identiferoai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12607600/index.pdf
Date01 September 2006
CreatorsOzen, Arda
ContributorsBeklioglu Yerli, Meryem
PublisherMETU
Source SetsMiddle East Technical Univ.
LanguageEnglish
Detected LanguageEnglish
TypeM.S. Thesis
Formattext/pdf
RightsTo liberate the content for public access

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