Distribution and summer diapause of Canthocamptus staphylinus (Jurine) (Copepoda: Harpacticoida) in Lake Ladoga
The spatial distribution of Canthocamptus staphylinus (Jurine) in Lake Ladoga was examined. C. staphylinus is one of the most numerous species of harpacticoids in the lake. It can dwell in almost all littoral biotopes. In profundal biotopes strongly exposed to anthropogenic influence (pollution and eutrophication) only this species of harpacticoid was found. A peculiarity of C. staphylinus biology is that in summer individuals are in the resting stage as cysts. In summer active individuals were found in littoral habitats at a water temperature of 20 °C, but their number was small in comparison with cold periods of the year. In the littoral zone the relative number of individuals in cysts was clearly related to water temperature. Twelve degrees temperature appears to be critical for development of littoral populations of C. staphylinus.
Morphological and Molecular-Genetic Polymorphism of Canthocamptus staphylinus Jurine (Harpacticoida, Copepoda, Crustacea)
External morphological and genetic structures of 94 individuals of Canthocamptus staphylinus Jurine (Harpacticoida, Copepoda, Crustacea) from ten European water bodies differing in type, including species type locality, have been analyzed. Significant distinctions of populations on six morphological features and morphometric indexes are established. The variability of both morphological and genetic markers is noted. As a result, two main species morph forms are allocated, typical and small. According to nucleotide, the variety of mitochondrial DNA harpacticoid specimens falls into ten haplotypes and three clades on the phylogenetic tree. One of them corresponds with the group isolated on morphological features (harpacticoids from the Sysola River basin, Komi Republic). The same-sex population from Lake Pääjärvi (Finland), which is morphologically indistinguishable from the population from a type locality, is considerably divergent by nucleotide sequences of mtDNA. The role of geographical isolation and ecological factors in C. staphylinus microevolution is shown.
Assessment of Ground Regeneration around Borehole Heat Exchangers between Heating Seasons in Cold Climates: A Case Study in Bialystok (NE, Poland)
Based on the experimental studies, the process of ground regeneration around the borehole loaded with brine-water heat pumps working exclusively for heating purposes in the period of four consecutive heating seasons in a cold climate was presented. The research was conducted in north-eastern Poland. The aim of the work is to verify the phenomenon of thermal ground regeneration in the period between heating seasons on the basis of the recorded data and to check whether the ground is able to regenerate itself and at what rate. It was noticed that the ground does not fully regenerate, especially during heating seasons with lower temperatures. In the analyzed period, from 22 September 2016 to 12 October 2020, the ground probably cooled irreversibly by 1.5 °C. In order to illustrate and evaluate the speed of changes in the ground, the one’s profile with an undisturbed temperature field was presented for each month of the year. The presented results can be a very important source of information for the analysis of geothermal conditions occurring in the ground. They can be used to verify mathematical models and conduct long-term simulations that allow us to see the complexity of the processes taking place in the ground.