Volume 44 (2015): Issue 2 (June 2015)

The study focused on the relationships between charophytes and the surrounding species composition and environmental factors in a lowland stream (Flinta stream, Western Poland). A total of 32 vegetation plots (4 m × 4 m) and 13 environmental variables were tested. Detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA) were used to describe the relationships between the species composition and the selected variables. Dominance curves of aquatic plants, response curves (GAMs model) of charophytes and other macrophytes to the velocity gradient (the most important environmental factor, the Monte Carlo test) were prepared. In this study, 2 species of charophytes were recorded: Chara vulgaris and Chara globularis and 5 other co-occurring macroscopic algae, 2 mosses and 10 vascular plants. In the studied stream, charophytes occupied the separate niche. Chara vulgaris stands with moss vegetation were found in stream sections with the highest velocity of the water current (0.29 m s-1 mean), and the Chara globularis (with dominant Potamogeton species), preferred sections with the smallest water current velocity (0.19 m s-1 mean).

Charophytes seem to respond to ecological gradients differently from mosses and vascular plants. These differences are related to current velocity, pH, conductivity and organic matter in bottom sediments, and to the niche differentiation associated with them.

Macrophytes determine the physical complexity of aquatic environments and provide a suitable habitat for colonization by microcrustaceans. We evaluated the effects of a seasonal growth pattern and structure of macrophyte species on epiphytic microcrustaceans collected from macrophyte surfaces (stems and leaves) in shallow wetlands from May 2011 to October 2012. In 2011, epiphytic microcrustaceans that preferred free-floating macrophytes (Spirodela polyrhiza and Salvinia natans) and submerged macrophytes (Potamogeton crispus and Ceratophyllum demersum) were affected by the seasonal growth of these species. Epiphytic microcrustaceans were abundant on the surface of Spirodela polyrhiza in June and August and on Salvinia natans in September and October. In 2012, epiphytic microcrustaceans preferred submerged macrophyte species over the free-floating ones. The results of stable isotope analysis showed that epiphytic microcrustaceans depend on epiphytic particulate organic matter (EPOM) from each macrophyte species rather than on suspended particulate organic matter. Small species (Coronatella rectangula, Pleuroxus laevis, and Chydorus sphaericus) used EPOM (dominated by epiphytic algae) on free-floating and submerged macrophyte species; however, relatively larger species (Ilyocryptus spinifer and Macrothrix rosea) used EPOM only from submerged macrophytes. Based on these findings, we conclude that the distribution of epiphytic microcrustaceans is determined by seasonal characteristics, morphology of macrophyte species, and abundance of food resources.

The research was carried out in mesotrophic Lake Krasne during winter with thick ice/snow cover. Water samples for biological and physicochemical analyses were collected vertically from the water column. Several phytoplankton groups were identified during the study, however, only two main groups of motile phytoplankton, Cyanophyceae (the dominant species − Planktothrix rubescens) and Cryptophyceae (Cryptomonas spp. and Plagioselmis nannoplanctica), were analyzed in the gradient of nutrients, light and thermal conditions. In the studied water column, values of physicochemical parameters did not vary in a wide range. Nevertheless, high discrepancies were noted in the values of phytoplankton biomass and the concentration of chlorophyll-a which had shallower maxima and deeper minima. Statistically significant relationships were found between the biomass of two main phytoplankton groups, light conditions (PAR) and depth, however, no significant relationships were found between the biomass, biogenic compounds and water temperature. The studies showed that in the winter season with ice/snow cover, cryptomonads and Planktothrix rubescens occupied different ecological niches and the main factor determining their distribution were light conditions. The ice/snow cover probably plays an important role in protection of P. rubescens winter filaments against photoinhibition.

The aim of the research was to determine the effect of irradiance on the content of carotenoids in the natural algae community occurring in the Baltic Sea: diatom Skeletonema marinoi, cryptophytes Teleaulax sp., Rhodomonas sp., and dinoflagellate Heterocapsa triquetra.

In the natural population of Skeletonema marinoi, the highest fucoxanthin content was observed in the morning and afternoon, unlike with diatoxanthin+diadinoxanthin, where a mean of 0.008 pg cell^-1 was found at dawn and at dusk, whereas maximum values were observed at noon (mean 0.017 pg cell^-1). Similar tendencies related to diurnal variations in the content of xanthophylls involved in the xanthophyll cycle occurred also in dinoflagellate Heterocapsa triquetra.

In cryptophytes Teleaulax sp. and Rhodomonas sp., no carotenoids of the xanthophyll cycle were detected. The content of alloxanthin showed diurnal variation from 0.048 pg cell^-1 to 0.085 pg cell^-1 and was not clearly correlated with the irradiance.

The Hel Peninsula is a 35 km long spit that extends into water depths of almost 60 m. Unlike most sandy barriers, the distal end of the Hel Peninsula is prograding into the deep water. This affects unique conditions for the evolution of this section of the Peninsula. The aim of this study is to determine the morpholithodynamic changes on the tip of the Hel Peninsula. Shore studies were performed in 2006-2008 and 2012. Measurements included: beach profiling, determination of shoreline and dune base line positions, and collection of sediment samples. The different nature of the eastern, central and western part of the Hel tip is evident. The eastern part is accumulative, the central part is variable with the general nature of strong and differently directed redeposition and accumulative periods, while the western part is highly erosive.

This study includes new records of soft corals found in the Turkish Straits System (Dardanelles) between 2013-2014. In the above-mentioned area, 50 stations were searched by scientific divers from the intertidal zone to a depth of over 45 m and the ecological characteristics with substrate differences were also recorded. A total of 47 cnidarians were examined during the surveys. Eleven anthozoan species (Aiptasia mutabilis, Alcyonium acaule, Andresia parthenopea, Calliactis parasitica, Cereus pedunculatus, Condylactis aurantiaca, Epizoanthus couchii, Maasella edwardsi, Pteroeides spinosum, Sarcodictyon roseum, Veretillum cynomorium) belonging to 4 orders are new to the Dardanelles strait, one of which is reported from the Marmara Sea. The current data contributed to the advancement of the knowledge about anthozoan species in the Turkish Seas.

Akdeniz and Akbuk lagoons are part of a shallow coastal ecosystem of great aesthetic and ecological importance, located in Muğla Province in the southern Aegean region of Turkey. In the present study, four expeditions to collect ostracods from these lagoons were conducted in May, July, October, and November of 2008. Benthic samples were obtained monthly and several environmental factors were recorded simultaneously in situ. The ecological preferences of the ostracods were monitored, and qualitative and quantitative samples were collected from three sites in Akdeniz lagoon and two sites in Akbuk lagoon. Three ostracod taxa (Cyprideis torosa, Loxoconcha elliptica and Cytherois fischeri) were identified from the Akdeniz lagoon sampling sites and one species (Cyprideis torosa) from the Akbuk lagoon sampling sites. We present and analyze the dominance and distribution of ostracod assemblages and their relationships to environmental factors: temperature, dissolved oxygen, percentage oxygen saturation, pH, redox potential, salinity, and electrical conductivity) using classification and ordination techniques. Canonical correspondence analysis (CCA) is used to characterize the relationship between ostracods and the environmental variables. Approximately 82% of the correlation between the community composition and environmental variables was explained by the first axis of the CCA ordination for the Akdeniz lagoon. The study revealed that the distribution and population density of ostracod species depends on the physicochemical properties of the environment. The reason for this is that Cyprideis torosa and Loxoconcha elliptica are euryhaline species.

The development of cyanobacteria and microcystin variation was studied during two years in response to periodical water-level regulation in modified Lake Tomaszne. Before the water entrance from a canal, the biomass of toxigenic cyanobacteria was 0.001-0.33 mg dm^-3, the microcystin concentration was below 1 μg dm^-3, and three variants of microcystins were detected. After the water entrance from the canal, the biomass of cyanobacteria increased to 1.3-7.1 mg dm^-3 with the dominants Aphanizomenon gracile and Dolichospermum planctonicum. After the water discharge from the lake, Planktothrix agardhii reached the highest biomass (2.3-6.6 mg dm^-3). During the mass development of toxigenic cyanobacteria, the total microcystin concentrations were mostly higher than 5 μg dm^-3 and the number of MC variants increased. Both Pl. agardhii and D. planktonicum accounted for microcystin production. The higher NH4-N concentrations supplied with water from the canal supported the biomass increase of Nostocales, whereas Pl. agardhii mass development was due to the low light intensity and high TP concentrations. Our study revealed that the use of nutrient-rich waters for the water management in the hydromorphologically modified lake supported the persistent development of cyanobacteria species leading to increased amounts of MC and a higher number of their structural variants.

The objective of the studies included a complex of three reservoirs (upper, middle and lower Arturówek) which play an important recreational role for the residents of the Łódź city and the surrounding areas. The reservoirs were constructed on the Bzura River and are located in the area of the Łódź Hills Landscape Park. The river, the ecological status of which was defined as moderate, has a great influence on the quality of water in the Arturówek reservoirs. A total of 36 planktonic samples were collected in 2011-2013 during spring, summer and autumn seasons. During the studies, the selected physical and chemical parameters were measured. In addition to taxonomic analysis of Cyanobacteria and algae, the analyses of abundance and biomass of phytoplankton and the concentration of microcystins in water were conducted. In 2013, ecohydrological rehabilitation of the Arturówek reservoirs was carried out. Investment works included: removal of the bottom sediments to reduce internal loads, construction of buffer vegetation zones (ecotones) and sedimentation-biofiltration systems to reduce the amounts of pollutants flowing into reservoirs with rainwater. Significant changes in the structure of phytoplankton were observed in 2013. Every year, the disappearance of Cyanobacterial blooms was observed in favor of an increasing contribution of algae.

Hirudinida comprise a constant component of benthofauna in running waters and their taxonomic composition is often analyzed to evaluate the environmental quality. However, the indicatory role of particular species is still arguable. Thus, it is very important to provide more detailed information on the impact of environmental parameters on the species structure within this group of invertebrates. Representatives of nine species were found in the investigated upland stream including mainly Erpobdella vilnensis and E. octoculata. The research has demonstrated that the hydromorphological conditions and feeding behavior are the main factors determining the taxonomic composition of leeches in particular sections of a watercourse.

The object of the present research was the Czarna Staszowska River, which is located in south-eastern Poland and which is a left tributary of the upper Vistula River. The length of the river is 61 km and its sources are situated in the Świętokrzyskie Mountains. The river flows across an area covered by Mesozoic rocks, mostly carbonate and sulfate ones. The upper and middle course of the river is of natural character, while increased pollution occurs downstream of the Chańcza Reservoir.

In the present study, the water quality of the Czarna Staszowska is investigated in the pure and polluted sections using diatom indices, such as IO − Diatom Index, IPS − Specific Pollution Sensitivity Index, GDI − Generic Diatom Index and TDI − Trophic Diatom Index. In the four river sections distinguished on the basis of the hydrology and the degree of water pollution, the occurrence of different indicator species was determined in the respective diatom assemblages. Indicator species were determined, i.e. characteristic of oligosaprobic and mesosaprobic, limestone and silicon-rich waters. Also taxa indicating an increased trophic status of the river (occurring in its polluted sections) were identified.

We report the results of recent field measurements of seawater thermohaline structure and transparency carried out in early summer 2014 in Puck Bay. Near-bottom, less saline waters occurred almost in the entire study area. Their occurrence in the shallow part of Puck Bay was accompanied by an increase in the seawater transparency. The most likely explanation of these observations is a submarine fresh groundwater discharge.

The occurrence of algal-cyanobacterial metaphyton mats in field (Konojad village) and artificial ponds (Poznań city) was investigated in the Wielkopolska region. The surface area of algal mats ranged between ca. 45% (natural pond) and 10% (artificial pond) of the total water surface, and the mats occurred from the water surface to the bottom; the algal diversity was similar in both types of ponds, i.e. about 10 taxa. The most frequently recorded and dominant taxa in small water bodies were: Spirogyra spp., Cladophora fracta in the artificial pond and Oedogonium spp., Cladophora rivularis in the natural pond. The dynamics of macroalgae demonstrated a pattern comprising different phases of taxa dominance. For example, April regarded as the first phase was characterized by a small amount of metaphyton, represented by Tribonema and Ulothrix taxa. In May, these species disappeared and were replaced by: Oedogonium spp. and Cladophora spp. which formed large aggregations in the field pond, and Spirogyra spp. which abundantly proliferated in the artificial pond. From June, however, Oedogonium and/or Cladophora significantly dominated in the mat structure and at the same time covered a large area of the water surface. The algal community was dominated by common algal taxa, among which single filaments of other taxa could also occur.