Limnol. Rev., Volume 19, Issue 3 (September 2019) – 4 articles , Pages 105-145

Most hydrotechnical buildings under construction demand the concrete mixture to be set directly under water. The main reason for such a procedure is to limit the washing away of the the concrete binding mixture and to increase the efficiency of organisation of work so as to ensure continuity in concreting. The impact on the aquatic environment of recent developments in concrete technology and the use of new components has not yet been established. Natural pebble aggregate containing portland cement and fugacious siliceous ash as a binder was used to prepare BP concrete samples, while concrete marked LB was composed with lightweight aggregate and portland cement as a binder. The aim of this paper was to answer to the question whether hydrotechnical concrete of different compositions (BP and LB) and the technology of setting in a water habitat have any influence on the life condition of commonly occurring Dreissena polymorpha (Mollusca, Bivalvia). The lethal effect of two types of freshly hardening concrete was observed. In the case of LB concrete the lethal outcome for D. polymorpha could be the effect of a considerable increase of electrolytic conduction in the test cultivation. In the case of BP the parameters of electrolytic conductivity and pH did not exceed the values appearing in lakes. The possibility of the occurrence of toxic compounds of D. polymorpha, arising from the reaction of the aquatic/lake environment or the elution of some components should be taken into account. D. polymorpha serves as an indicator of toxicity in the aquatic environment and therefore can be used as a model organism in the analysis of the influence concrete on the natural environment. The results obtained in this study indicate the significant impact of modern chemical composition of concrete on the aquatic environment and the living organisms that cover it. They underline the need for research based on the hydrobiont reaction to the substances used in the natural environment. Full article

One of the adverse impacts of climate change is drought, and the complex nature of droughts makes them one of the most important climate hazards. Drought indices are generally used as a tool for monitoring changes in meteorological, hydrological, agricultural and economic conditions. In this study, we focused on meteorological drought events in the High Ziz river Basin, central High Atlas, Morocco. The application of drought index analysis is useful for drought assessment and to consider methods of adaptation and mitigation to deal with climate change. In order to analyze drought in the study area, we used two different approaches for addressing the change in climate and particularly in precipitation, (i) to assess the climate variability and change over the year, and (ii) to assess the change within the year timescale (monthly, seasonally and annually) from 1971 to 2017. In first approach, precipitation data were used in a long time scale e.g., annual and more than one-year period. For this purpose, the Standardized Precipitation Index (SPI) was considered to quantify the rainfall deficit for multiple timescales. For the second approach, trend analysis (using the Mann-Kendall (M-K) test) was applied to precipitation in different time scales within the year. The results showed that the study area has no significant trend in annual rainfall, but in terms of seasonal rainfall, the magnitude of rainfall during summer revealed a positive significant trend in three stations. A significant negative and positive trend in monthly rainfall was observed only in April and August, respectively. Full article

The aim of the work was to analyze the influence of wave activity on invertebrate fauna living in the littoral zone. For this purpose, an algorithm was developed to analyze spatial and meteorological data, calculating the values of fetch and wind exposure. The taxonomic composition of the fauna and the values of selected water quality indicators were analyzed against the background of varied wind exposure, trophy, and various habitats. A significant negative impact of wind exposure on the taxonomic variety of the macrozoobenthic community, the number of Coenagrionidae damselflies and Baetidae mayflies was found. It is difficult to separate the impact of waves on the fauna from the impact of other natural and anthropogenic factors, because those factors may also be affected by water movements. The tool produced as part of this work can also be used to further investigate the issue of impact of waves on all the communities living in the littoral zone. Full article

The article presents the ice phenology of Lake Ostrzyckie, which is a water body covering an area of 308 ha located in the central part of the Kashubian Lakeland, northern Poland. The analysis presented in the article is based on data from daily ice phenomena monitoring for the period of 1971–2010. Data including forms of lake ice, as well as the thickness of the ice cover were obtained from the Institute of Meteorology and Water. In order to present relations between the ice phenomena and air temperature the meteorological data from the Gdańsk University Limnological Station in Borucino were used. The article presents changes in the duration time of the ice seasons and changes in the ice cover duration time in relation to winter season (November–April) temperatures. The structure of the ice phenomena duration period observed on Lake Ostrzyckie consists of three different stages of ice cover formation. 94% of this time the lake is covered by permanent ice cover, the freezing period takes about 5%, and the break-up takes only 1% of the ice phenomena duration period. In general the ice phenomena in the lake can occur only in the years when the average air temperature in the winter is lower than 5.0 °C, whereas the permanent ice cover is created when the average air temperature of the winter season is lower than 4.8 °C. The maximum thickness of the ice cover is usually 23 cm, and the average is 14 cm. Full article