Determining the roles of water level and fish predation on submerged plant growth in shallow lakes using mesocosm experiment

Download

index.pdf

Date

2011

Author

Bucak, Tuba

Metadata

Show full item record

Item Usage Stats

188
views

122
downloads

Four-month mesocosm experiment from June 1st to September 25th, 2009, was conducted to determine the e ffect of water level di erence in combination with fish predation pressure, on submerged macrophyte development, in an eutrophic shallow lake. Eff ect of water level fluctuation was simulated by placing enclosures to the di fferent water depths that included 0.8 m, 1.6 m and 2.3 m on Lake Eymir. These enclosures having a cylindirical shape and 1.2 m diameter, were open to sediment and atmosphere interaction. The highest water level mesocosms were cancelled after fifth sampling due to rapture in the bags, hence this thesis does not include the results of 2.3 m. At each depth, half of the enclosures were stocked with planktivo-omnivorous fish (Tinca tinca, Alburnus spp.) which are natural fauna of Lake Eymir. Before stocking of fish, ten shoots of Potamageton pectinatus were added to all of the enclosures in order to observe submerged macrophyte development. Sampling for physico-chemical parameters, zooplankton, chlorophyll a, PVI% and periphyton was conducted weekly for the first five weeks, last six samplings were done biweekly. Macrophyte harvesting for dry weight estimation was done at the end of the experiment. Throughout the experiment water level decreased 0.41 ± 0.06 m in each enclosures. Water level was so critical for macrophyte development that no significant macrophyte growth was observed in enclosures located at 1.6 m (HW). However, fish predation did not prevent the growth of macrophyte in enclosures located at 0.8 m (LW) but it was important in HW enclosure for a ffecting water clarity. Fish predation a ffected chlorophyll a, zooplankton and nutrient concentrations and the eff ect was mostly pronounced at LW enclosures. They had high chlorophyll a and nutrient concentrations but it did not repress macrophyte growth as in temperate lakes. Despite high water clarity in HW fishless enclosures, very low macrophyte biomass may be attributed to enhanced periphyton development. Zooplankton community shifted to small sized ones under fish predation while fishless enclosures had higher zooplankton /phytoplankton ratio for each depth. Hence, regarding these results it can be stated that decrease in water level can compensate the negative effects of fish predation on macrophyte growth in warm Mediterranean lakes.

Subject Keywords

Hydrology., Biological Sciences.

URI

http://etd.lib.metu.edu.tr/upload/12612995/index.pdf
https://hdl.handle.net/11511/20479

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Impact of water level fluctuations and fish on macroinvertebrate community and periphyton growth in shallow lakes - a mesocosm approach Saraoğlu, Ece; Beklioğlu, Meryem; Department of Biology (2012) A mesocosm experiment was conducted in Lake Eymir between June – September 2009 in order to elucidate the effects of water level changes and fish predation on periphyton growth and macroinvertebrates in semi-arid shallow lakes. Twenty four cylindrical enclosures, each with 1.2 m diameter, open to lake bottom and atmosphere, were placed at three different depths, i.e. 0.8 m (low water level, LW), 1.6 m (high water level, HW) and 2.3 m (however, data regarding the enclosures at 2.3 m were excluded in this stu...
Assessment of flood hazards due to overtopping and piping in Dalaman Akköprü Dam, employing both shallow water flow and diffusive wave equations Yilmaz, Kutay; Darama, Yakup; Oruc, Yunus; Melek, Abiddin Berhan (2023-01-01) This study was carried out to determine flood propagation using shallow water equations (SWEs) and diffusive wave equations (DWEs) to reveal how the flood modeling results differ in terms of flow depth, flow velocity, and hazard level. The solution methods were tested based on the hypothetical failure of the Dalaman Akköprü Dam resulting from two failure mechanisms: overtopping (OT) and piping (PP). A 2D hydraulic model was constructed using HEC-RAS to determine the propagation of flood waves due to the fai...
Constraining the cause of the end-Guadalupian extinction with coupled records of carbon and calcium isotopes Jost, Adam B.; Mundil, Roland; He, Bin; Brown, Shaun T.; Altıner, Demir; Sun, Yadong; DePaolo, Donald J.; Payne, Jonathan L. (Elsevier BV, 2014-06-15) A negative delta C-13 excursion in carbonate sediments near the Guadalupian/Lopingian (Middle/Late Permian) boundary has been interpreted to have resulted from a large carbon cycle disturbance during the end-Guadalupian extinction event (ca. 260 Ma). However, the carbon isotope data alone are insufficient to uniquely determine the type and magnitude of perturbation to the global carbon cycle. Calcium isotopes can be used to further constrain the cause of a carbon isotope excursion because the carbon and cal...
Analysis of cellulase and polyphenol oxidase production by southern pine beetle associated fungi Valiev, Abduvali; Ögel, Zümrüt Begüm; Klepzig, Kier D. (Springer Science and Business Media LLC, 2009-09-01) In this study, the production of extracellular enzymes by fungi associated with southern pine beetle was investigated for the first time. Cellulase and polyphenol oxidase production were analyzed for three beetle associated fungi. Only the mutualistic symbiont Entomocorticium sp. A was found to produce cellulases and polyphenol oxidase. In time course analyses of cellulase production in batch cultures, Entomocorticium sp. A showed maximum activity of 0.109 U/ml and 0.141 U/ml for total cellulase and endoglu...
Estimation of carbon dioxide flux in shallow lakes in Turkey Kalvenas, Jennifer; Beklioğlu, Meryem; Department of Biology (2014) The role of Turkish shallow lakes as a sink or source of carbon from 44 shallow lakes sampled once from 2006 – 2012 over six degrees of latitude is analyzed in terms of spatial resolution. Two of the lakes (Eymir and Mogan) were sampled over the spring, summer, and fall seasons from 2006 – 2010 under dry and wet periods and analyzed for temporal resolution. An equation using pH, specific conductivity, wind speed, temperature, and acid neutralizing capacity (ANC) was used to determine CO2 fluxes (Trolle et a...

Citation Formats

T. Bucak, “Determining the roles of water level and fish predation on submerged plant growth in shallow lakes using mesocosm experiment,” M.S. - Master of Science, Middle East Technical University, 2011.