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Content of iron and quality of organic matter as a factor affecting stabilization of carbon and nutrients in fresh water ecosystems.
Osafo, Nana O. A. ; Jan, Jiří ; Porcal, Petr ; Borovec, Jakub
The effect of watershed geochemistry, in terms of soil pH, Fe concentration and organic matter quality, on the stability of organic carbon and nutrients level in freshwater sediments of shallow lakes was studied. Twelve fishponds were divided into two groups based on the typical soil pH: i) watershed with acidic soils (pH 5.1 – 6.3) rich in Fe called H_Fe and ii) watershed with neutral pH soils (pH 6.8 – 7.6) poor in Fe called L_Fe. The parameters of the water column, pore water and sediment chemical extractions were compared. A higher concentration of hydrated Fe oxides, together with the aromatic character of organic substances were shown to highly contribute to the overall stabilization of the sediment. Conversely, low Fe concentrations were accompanied by lower mineralization of sediments and a higher risk for the aquatic ecosystem in terms of nutrient release or the development of anoxic conditions.
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Effect of terminal electron acceptors on biogeochemical processess and phosphorus cycle in sediment
Jan, Jiří ; Borovec, Jakub ; Petráš, D. ; Osafo, Nana O. A. ; Tomková, Iva ; Hubáček, Tomáš
This study focuses on the phosphorus (P) release from sediment of inflow part of Vranov reservoir under different availability of terminal electron acceptors, mainly dissolved O2 and NO3-. To understand the cycling of P in sediments, sediment cores were incubated for five weeks in three parallel variations that simulated: i) anoxia with depleted NO3-, ii) O2 saturated water column and iii) O2 saturated water column in the presence of high concentrations of NO3-. Evaluating the release of P and the impact of Iron (Fe) and its metabolism in sediment under the different conditions, water above the sediments was monitored, porewater composition and different P fractions in the sediment were analyzed.
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Methodology for identification and quantification of sediments in water reservoirs
Borovec, Jakub ; Jan, Jiří ; Vrzák, J. ; Knotek, J.
The study was designed to find methodical procedures for effective and accurate detection and quantification of bottom sediments in water reservoirs, including an assessment of their impact on the quality of water in the reservoirs. The study summarizes the overall problem of sediments in the water bodies. Advantages and disadvantages of methods and equipment widely used for sediment sampling procedures for their quantification are assessed. The result is a developed optimal methodical procedure for proper spatial localization of sediments and determination of their volumes in given zones. The methodology also includes a precise procedure for the evaluation of its chemical parameters and the P cycle with further determination of the sediment potential to deteriorate water quality in the reservoirs.
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