Mineral Phosphorus Concentrations Research Articles

Hydrochemical conditions of three lakes located in the West Pomeranian region in the annual cycle

The objective of the study was to trace the variability of the hydrochemical conditions in three lakes of the West Pomeranian Voivodeship (Poland) – Starzyca, Maszewskie and Nowogardzkie in the annual cycle. The research was done in 2018–2019, and samples for analysis were collected 4 times a year. All analyses were performed applying standard methods. Such hydrochemical indices were determined as dissolved oxygen, chemical oxygen demand, content of orthophosphates, total phosphorus, nitrite, nitrate, ammonium, chlorophyll a and iron. The study showed that all lakes in the research cycle were characterised by a polymictic type of water mixing, and the trophic level, based on the adopted criteria, indicated advanced eutrophy, which may also be caused by anthropogenic pressure. Oxygen conditions characterised by deoxidation of the waters in the bottom layer in the spring and summer seasons, and clear oxygenation in the surface water layer (in Lake Maszewskie reaching even 188.5% in the spring) confirm the significant advancement of the eutrophication process. The supply of phosphorus and nitrogen in spring from pelagic waters in the waters of the examined lakes influences concentrations of chlorophyll a in the summer. The influence of “internal supply” (bottom waters and bottom sediments) on the amount of nutrients available for autotrophs is clearly visible in the analysed lakes – an increase in nitrogen and mineral phosphorus concentrations in relation to surface waters was observed in the bottom layer.

Spatial variability of biogenic elements and organic carbon content in the tributaries of Lake Baikal

The article considers the features of biogenic elements and organic carbon (Corg) content spatial variability in the Lake Baikal tributaries. The role of hydrological conditions and landscape-geochemical features in the chemical elements flow formation is shown. It was found that organic carbon in the river waters is represented mainly by its dissolved form. In the lower reaches of the Selenga, erosion processes and economic activity in the catchment area increase the proportion of suspended forms of organic carbon and mineral phosphorus. In the river delta under the influence of the sedimentation and the intake of organic matter formed during aquatic vegetation decomposition, the content of dissolved Corg increases with a contemporary decrease in its suspended form. As a result of intensification of production and destruction processes in well-heated areas of the delta, a significant decrease in the concentrations of mineral phosphorus and an increase in organic phosphorus occur.

Закономерности и факторы формирования зимнего гидрохимического режима Угличского водохранилища

The article presents the results of the study of the winter hydro/chemical regime of the Uglich reservoir which is the second stage of the Volga-Kama cascade of reservoirs. In winter period the main influence on the formation of the hydrochemical regime of the Uglich reservoir is exerted by water coming from the Ivankovsk reservoir which located upstream. It was found that water in the reservoir is hydrocarbonate, mineralization varies from 243 to 351 mg per liter, calcium and magnesium concentrations reach 60.9 and 17.5 mg per liter. Concentrations of mineral phosphorus in the reservoir are 0.043–0.076 mg per liter, total gross phosphorus in the upper relief of the Uglich HPP reach 0.138 mg per liter, nitrate concentrations are 0.14–0.84 mg per liter.The main indicators of hydro/chemical regime of the Uglich reservoir have spatio-temporal variability. Its change from year to year, as well as from target to target. Global climate changes have not yet had a significant impact on the winter hydro/chemical regime of the reservoir.

The rates of organic matter destruction in the central part of the Arctic Basin

The intensity of the processes of organic matter (OM) destruction in the deep-water part of the Arctic Basin is considered in terms of the activities of hydrolytic enzymes (alkaline phosphatase and proteases) and of redox enzymes of the electron transport system (ETS). High concentrations of mineral phosphorus are shown to cause low phosphatase activity (0.000–0.005 μM P/l h). The average time of the phosphate recycling amounted to about 240 h. The ranges of the total and specific activity of protease are 0.000–0.192 mg of azocasein/(l h) and 0.00–3.57 mg of azocasein/h mg of protein, respectively. It is found that the microplankton production of exo- and endopeptidase in the Arctic Basin is controlled by the concentration of nitrates in the water. The values of the total and the specific activities of the ETS enzymes vary within 0.27–8.96 μl O2/(l h) and 8.4–583 μl O2/mg of protein h, respectively. It is shown that the maximum values of the total activities of the hydrolytic and redox enzymes are characteristic for the photic layer. The vertical fluxes of organic carbon from the photic layer, being calculated by the activity of the ETS enzymes, amounted to 220–600 g of Corg/year m2. The presence of ice intensifies the redox processes by factors of 2–15.

Mathematical modeling of mineral nitrogen, mineral phosphorus transfer and water current in the Curonian Bay

4 Laboratory of Nuclear Hydrophysics, Vilnius Gediminas Technical University, Saulėtekio 11, LT-10223 Vilnius, Lithuania E-mail: linasg@dtiltas.lt Monitoring of mineral nitrogen, mineral phosphorus concentrations and water current ve­ locities in the northern part of the Curonian Bay was carried out on April 10 and 11, 2002. Investigations of the mentioned parameters were carried out in the Lithuanian part of the Curonian Bay between Kaliningrad Region and the Klaipėda Strait, and the hydrometeoro­ logical situations were considered simultaneously. Mineral nitrogen concentration in the period of observations were varied within 1.240 and 1.711 mg/l, and mineral phosphorus concentrations ranged from 0 to 0.009 mg/l. Wa­ ter current velocity values ranged between 0.01 and 0.3 m/s. Nitrogen and phosphorus promote biological water pollution. Transfer of these admix­ tures depends on water stream velocities and direction. Therefore, mathematical modeling of the processes of admixture transfer and water current was proposed. The method of objective analysis was used for calculating the concentration field of mineral nitrogen, mineral phosphorus and the field of water current velocities. Because of the lack of measurement results, repeated calculations were carried out to find an optimum coincidence of the calculation and measurement data. Autocorrelation functions of mine­ ral nitrogen, mineral phosphorus and water current velocities were calculated. The agreement between the measurement and calculation results was satisfactory.

Long-term variability of oxygen and mineral phosphorus concentrations in Lake Dal’nee (Kamchatka)

Many-year data on the concentrations of O2 and mineral phosphorus in a fattening-spawning water body for the Pacific salmon (red salmon) are presented; the seasonal and year-to-year dynamics of these con-centrations are analyzed. It is found that the lake water mass features a high concentration of O2, the upper 20-m layer being most aerated. It is shown that the year-to-year variability of the concentration of O2 dissolved in the lake water depends on the amount of organic matter coming with groundwater and surface runoff. The oxygen and phosphorus regimes of the lake at low and abundant entries of puberal red salmon for spawning are considered.

Use of the Ichthyohaematological Studies in Ecological Monitoring of the Reservoirs

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