The degree of enhancement was correlated with the SOD increase and the rate of resedimentation -i.e. share of fine-grained sediment particles.It seems that for this reason shallow deposits from accumulation zones of lake Druzno, physically very like to those from profundal of lake Partqczyny, showed similar character of phosphorus release dynamics.For the more precision laboratory measurements a micro-cosm was constructed. Modular construction consists of teflon rings, having different functions, inserted between glass tube segments.It allows to observe the release of phosphorus at different physical and chemical properties of sediment and water, for example different kind of deposits, desired temperature profile and oxygen regime.The detailed description of the micro-cosm and preliminary results are presented.Diffusive fluxes of dissolved phosphate, the rates of oxygen consumption and sediment accumulation were calculated using new formulas of Dr I. B. Misandrontsev (1990). All the formulas are based on the equations of macrokinetics processes near the sediment-water interface under the steady-state conditions. There are two independent methods to calculate the diffusive fluxes of phosphate using the formulas. One is based on rates of sediment accumulation and organic phosphorus content in surficial sediment layers, another on the shape of concentration profile of inorganic phosphorus in interstitial waters.To test the Misandrontsev's formulas other methods have been used for different sediments of several lakes. Data obtained during short period laboratory measurements with undisturbed sediment cores in chambers and calculated from the Misandrontsev's formulas (two independent methods) are similar, while the fluxes calculated from Fick's first law of diffusion are different from ones measured in chambers. This indicates that Misandrontsev's formulas give accurate results.These formulas were applied for calculation of oxygen consumption and sediment accumulation rates and phosphorus fluxes from sediments of the largest European Lake Ladoga. Sediments of this lake are of various types from sands to fine-grained silts and clays. There are considerable bottom areas with one or several layers a few centimetres beneath the sediment-water interface, which are enriched with Fe or Mn. These layers prevent vertical diffusion of phosphate within sediment. The overlying water is usually well-aerated during the year, thus the exchange processes take place mainly under aerobic conditions.Concentrations of phosphorus and organic carbon in the solid phase of sediment, inorganic and total phosphorus in interstitial waters, dissolved oxygen in overlaying water, porosity and some other parameters were determined in samples from 46 sites of bottom area. All the calculated parameters vary widely. Patterns of space distribution of these characteristics are presented. The least values are connected with sandy sediments of southern shallow areas of the lake, and the greatest with fine-grained sediments of deep region and some littoral...
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