Volume 46 (2017): Issue 1 (March 2017)

We investigated diatom assemblages in surface sediments of 46 lakes in northern Poland and developed a diatom-based transfer function to infer epilimnetic total phosphorus (TP) concentrations. Multivariate ordination techniques (DCA, CCA) were used to identify major environmental gradients and to evaluate the effect of environmental parameters on the distribution of diatoms in the modern diatom dataset. The transfer function was developed using PLS, WA and WA-PLS models, and applied to a varved sediment core from Lake Żabińskie, AD 1888-2010. Annually-resolved quantitative reconstruction of TP concentrations shows that multidecadal changes in the TP level reflect the local settlement history, land-use changes and development of agriculture and tourism. The period of high trophic levels with maximum values of TP was documented until the late 1920s. In the 1930s-1970s period, TP generally decreased and eutraphentic flora was partly replaced by oligotraphentic and oligo-mesotraphentic diatom taxa. The reconstructed TP concentrations have started to increase from the 1970s. After the 1950s, strong short-term fluctuations of TP values were noted and explained by interactions between meteorological conditions, water column mixing and nutrient cycling in the lake.

The main objective of this paper is to report new information about the distribution and ecology of a recently described diatom species, Geissleria gereckei. The opportunity for updating the information on the distribution and ecology of the species was provided by the finding of well-developed G. gereckei populations on the lithic material and bryophytes in the Raška and Mlava rivers (Serbia). For several years after the first description, G. gereckei has been known only from the type locality and from another spring in the Dolomiti Bellunesi National Park (the south-eastern Alps). After accurate LM and SEM observations, we provide evidence for the occurrence of the species also in the two above-mentioned rivers in Serbia, as well as in the south-western and south-eastern Alps. After an extensive literature search, it appears that the species is known with certainty only from these sites. Our observations and details from the literature suggest that the species is able to occupy a much broader ecological niche than the very-specific one observed at the time of discovery. The two main determinants for the species’ occurrence appear to be the carbonate nature of the catchments or aquifers, and the ability of the species to be competitive in habitats or microhabitats exposed to seasonal desiccation.

⁹⁰Sr activity was determined in Zostera marina collected in the Gulf of Gdańsk in 2008-2013. ⁹⁰Sr activity in Z. marina from Jama Kuźnicka and Klif Orłowski range from 0.83 Bq kg⁻¹ d.w. to 3.78 Bq kg⁻¹ d.w. and from 0.68 Bq kg⁻¹ d.w. to 4.95 Bq kg⁻¹ d.w., respectively. The plants collected in spring-summer showed significant differences between ⁹⁰Sr content in blades - 1.55 Bq kg⁻¹ d.w. in 2011 and 2.18 Bq kg⁻¹ d.w. in 2013, and in roots - 7.75 Bq kg⁻¹ d.w. and 11.44 Bq kg⁻¹ d.w., respectively. The reduction in ⁹⁰Sr concentrations in Z. marina roots to 1-2 Bq kg⁻¹ d.w. in summer resulted from the transport of this element to the young parts of the plant. In autumn and winter, the ⁹⁰Sr content in the blades of Z. marina was increasing and reached the maximum of 3.77 Bq kg⁻¹ d.w. This could be explained by the process opposite to dilution, related to the biomass reduction and strontium concentration in the plant tissues. Changes in ⁹⁰Sr concentration in Z. marina tissues are affected by isotope concentration in seawater as well as by salinity, which affects the concentration of Ca²⁺ - for which Sr²⁺ is a chemical analogue.

The paper presents morphological and ecological characteristics of Prestauroneis tumida Levkov recorded for the first time in Poland. The diatom Prestauroneis tumida Levkov was found in the microbenthos of the Czarna Staszowska River (left tributary of the Vistula River, south-eastern Poland). This diatom species was present in the upper section of the river (sampling sites: 1 – Drogowle, 2 – Raków) where saprobic state varied from oligosaprobic to beta-mesosaprobic. Dimensions of the valve were as follows: length 30-44 µm, width 8-11 µm and 13-16 striae in 10 µm. Our research updates the morphological diversity data such as measurements of valves in terms of width and the number of striae. The accompanying species of Prestauroneis tumida belonged to the group of good water quality indicators, from oligo- to mesosaprobic ones. Some of the identified species were indicators of alkaline, calcium-rich waters.

Oxbow lakes are typical elements of meandering watercourses and are considered to be key components of floodplains of natural rivers. A permanent connection with the river promotes the use of these water bodies by ichthyofauna as spawning grounds, shelter for fry, feeding and wintering grounds. The aim of this study was to determine which rheophilic species inhabit oxbow lakes and how environmental conditions affect habitat selection and fish behavior. Analyses were conducted on six oxbow lakes of the Warta River in the Koło-Poznań section. Fish and water samples were collected for three years, in spring, summer and late autumn. Variation in environmental conditions in the analyzed water bodies results in a considerable diversity of the ichthyofauna, including rheophilic species, in individual seasons of the year. In the course of the study, nine rheophilic fish species were recorded, including four from the lithophilic reproductive guild having the highest environmental requirements. Relative abundance of rheophilic species in the dominance structure ranged from 0 to 100%, depending on the reservoir and seasons, with an average of 7% for all catches. For comparison, their relative abundance in the adjacent parts of the river was 12 and 23%.

Bacteria constitute a large domain of prokaryotic microorganisms present in marine ecosystems and play a significant role in energy flow and nutrient cycling. Bacterial community changes may affect organisms of higher trophic levels. We conducted field monitoring to study the relationship between dissolved organic carbon (DOC) and the bacterial community in the coastal waters of Incheon, Korea. Results showed that abiotic factors, such as temperature, salinity, dissolved oxygen (DO), pH, and dissolved inorganic nutrients, were not significantly different among the sampling sites during the study period. On the other hand, nutrient conditions were significantly different among the sites between 2012-2013 and 2014. Nitrogen was the limiting factor from 2012 to 2013, and phosphate in 2014. Biotic data showed that DOC affected both bacterial abundance and bacterial composition. A similar fluctuation pattern was observed for phytoplankton and Chlorophyll a. However, a close correlation was not observed between phytoplankton and other variables. Redundancy analysis (RDA) and Pearson correlation analysis of abiotic and biotic factors also showed that DOC concentration and bacterial abundance were correlated. Therefore, DOC appears to be an important factor affecting bacterial abundance and composition in the coastal waters of Incheon, Korea.

The Southern Baltic seabed is mainly composed of marine sediments situated on glacial and fluvioglacial deposits. In the Kołobrzeg region, however, solid rocks are located at the shallow subbottom. In order to determine the exact distribution of the rocks, some analyses of sonar images, underwater photos, sediment samples, seismoacoustic profiles and bathymetric data have been performed. The outcrops of Jurassic sandstones and mudstones have been documented. The geological structure of the area is presented, while the fact that the present seafloor relief is determined by the shallow uneven top surface of the Jurassic rocks is emphasized. The seabed has been classified as rock platform-constrained. The seafloor is a sediment-poor abrasion platform, within which marine sandy sediments are transported, mainly toward offshore, on the firm, stiff or hard surface of glacial deposits and Jurassic solid rocks. This results in a lack of material for the reconstruction of the beach after storms. Many of the commonly used methods for studying the condition and changes of the coast cannot be used in this type of terrain due to the presence of a thin and discontinuous dynamic layer lying on the erosion-resistant rocks of the geomorphologically complex seafloor.

Charophytes are a group of green algae that grow in various types of water ecosystems and are characterized by a high degree of plasticity and morphological variation. To analyze the genetic diversity and taxonomic rank of several species from the genus Chara, the fingerprinting technique of Amplified Fragment Length Polymorphism (AFLP) was applied. We studied species that belong to sect. Grovesia (C. tenuispina, C. globularis, C. virgata, C. aspera and C. strigosa) and two species from the sect. Hartmania (C. intermedia and C. hispida). The individuals were collected in the field in north-eastern, central and eastern Poland. The species were identified based on morphological features and then analyzed using the AFLP fingerprinting method. UPGMA clustering and PCA analysis as well as morphological analysis revealed a clear separation of C. tenuispina and C. globularis, which formed separate clusters supported by high bootstrap values. Therefore, these species were distinguish as separate taxa, rather than varieties of C. globularis. Similarly, C. virgata also formed a separate cluster, thereby confirming that this taxon is a separate species, rather than a variety of C. globularis. The AFLP analysis did not show any differentiation between C. aspera and C. strigosa. The presented results do not fully support the taxonomic interpretation for the existence of several polymorphic species with numerous variations and forms, however, in some examples, the distinctive nature of the reproduction system may be used as a distinguishing feature of the taxa.

Mycological and hydrochemical research was conducted in two different types of reservoirs connected with the Narew riverbed (three tributaries and three lotic oxbow lakes) in two growing seasons. The obtained results seem to indicate that more favorable conditions for the development of the analyzed microorganisms prevailed in the studied tributaries of the Narew. A total of 36 species of fungi and fungus-like organisms were identified in these tributaries in spring and 35 in autumn, while respectively 32 and 26 species in the lotic oxbow lakes. Six taxa not identified in the oxbow lakes were found only in the tributaries of the river. They were: Alternaria alternata, Allomyces moniliformis, Catenaria anguillulae, Leptomitus lacteus, Rhipidium parthenosporum and Saprolegnia diclina. On the other hand, only two species occurred only in the oxbow lakes (not recorded in tributaries) (i.e. Catenophlyctis variabilis and Rhizophlyctis rosea).

The differences observed in the microfungi species composition in the studied ecosystems are associated, among others, with the time of the year and physicochemical properties of the water. Hydrochemical parameters such as temperature, pH, Mg, N-NH₃, N-NO₃, P-PO₄ and suspended solids showed positive correlation, and sulfates, chlorides, Ca, Fe correlated negatively with the number of taxa observed.

The presented study aimed at comprehensive assessment of the Perccottus glenii (Amur sleeper) impact on the aquatic ecosystem. Our objective was to analyze the diet, the characteristics of the prey and the feeding behavior of the Amur sleeper. Fish (349 individuals) were captured by electrofishing in autumn 2012. To estimate the dietary importance of each prey category, we calculated the percentage or proportion of each food item and its frequency of occurrence. The Costello graphical method was applied to describe the feeding strategy and prey importance. A total number of 55 taxa of benthic macroinvertebrates were identified, amounting to a total of 2448 individuals. The digestive tract was empty in 48 individuals of the Amur sleeper. The most frequent prey items of the Amur sleeper were Asellus aquaticus L, Baetis spp., the Chironomidae family which was represented by 22 taxa identified to the genus and species levels, Corixa spp. and Physa acuta Drap. Depending on the frequency of prey items, two categories of size classes with specific diet compositions in the Amur sleeper populations were determined. Feeding strategy, cluster indicators of the size classes and traits of macroinvertebrates were the main aspects covered by our study of the Amur sleeper feeding behavior.

The present paper reports the first observation of the North American amphipod Melita nitida Smith, 1873 in the Gulf of Gdańsk (the southern Baltic Sea, Poland). In 2014, 13 adult specimens, including 3 males, were collected in the Port of Gdynia, which is located in the western part of this waterbody.

Pleodorina indica (Iyengar) H. Nozaki is a rare species from the Volvocaceae family (Chlorophyta, Volvocales), which naturally occurs in aquatic ecosystems of the tropical climate zones. This is the first record of this species I in Poland in a flow-through man-made reservoir on the Olechówka River in Łódź. The sampling site of P. indica in Łódź is the northernmost site in Europe. Among other records, the species has been also reported from Austria in 1996 and the Czech Republic in 2003. During the summer of 2015, abundant occurrence of this species was observed at the sampling site, at extremely high air and water temperatures. Physical parameters in the reservoir and the duration of the P. indica bloom were measured. In addition, morphological features of the species were observed with the use of light and confocal microscopy.

Reimeria ovata (Hust.) Levkov & Ector was found during field research conducted from 2013 to 2015 on the Wołosaty stream and its selected tributaries. Valves measured in the studied material are narrower than valves described in the currently available literature and have more striae per 10 µm. Specimens of R. ovata observed under a light microscope were morphologically very similar to those of R. sinuata, particularly in the case of small individuals. The precise distinction between these two species was only possible under SEM. R. ovata has been found in cold, oligotrophic waters, highly saturated with oxygen, with alkaline or circumneutral pH, but never in large numbers. The aim of this work was to identify the new locations of R. ovata and to determine morphological and ecological characteristics of this species.