Oceanological and Hydrobiological Studies

Abundance, biomass, and taxonomic composition of the ciliate community were studied in the surface waters along a transect between 50°S 61°W and 48°N 5°W (Atlantic Ocean, March-April 2011). The abundance of heterotrophic ciliates was low in the equatorial zone (280–320 cells l−1, 0.11–0.12 μg C l−1), but it increased toward both the northern and southern temperate zones with the maximum abundance observed at 44°S (2667 cells l−1, 0.82 μg C l−1). This pattern resembles the global distribution of oceanic primary production, which is low at lower latitudes and high in temperate zones. In temperate zones ciliate abundance peaks during spring and fall. Thus, because the present study was carried out during spring in the northern hemisphere and austral fall in the southern hemisphere, the ciliate abundance at higher latitudes was additionally elevated. Functionally autotrophic Mesodinium rubrum was only observed in the northern hemisphere and tropical waters. Its maximum abundance was observed at 48°N (1080 cells l−1, 1.14 μg C l−1). The most frequently observed ciliates were oligotrichs and choreotrichs. Other important ciliates were haptorids (including M. rubrum) and hypotrichs.

Abstract Large and harmful cyanobacterial blooms appeared in two newly-built artificial reservoirs shortly after being filled with water. Taxonomic composition of cyanobacterial communities was highly variable in both water bodies and fast species replacement was observed. In the first year of the operation of the smaller Konstantynów Reservoir, the mass development of Anabaena flos-aquae and Planktolyngbya limnetica (48.7 and 53.6% of the cyanobacterial abundance) occurred in summer, while in autumn the dominance of Planktothrix agardhii (99.9%, 14.95 × 106 ind. Dm−3) was noted. The surface scum developed in summer consisted of An. flos-aquae that contained high amounts of anatoxin-a (1412.4 μg AN-a dm−3 of scum) and smaller amounts of microcystins (10 μg eq. MC-LR dm−3 of scum). In the larger Kraśnik Reservoir, Aphanizomenon flos-aquae occurred in high abundance in spring and summer, however, it was replaced by different species of Microcystis (1.3 × 107 ind. dm−3) which created thick surface scum. Simultaneously, a hazardous increase in the total concentration of microcystins (from 13.6 to 788.5 μg eq. MC-LR dm−3 of water with scum) and anatoxin-a (from 0.03 to 43.6 μg dm−3) was observed.

Ecosystem models, used mainly in studying the interactions between different trophic levels, can also be used for ocean circulation model skill assessment, with the help of satellite ocean color data. This paper presents how the use of a simple NPZ primary productivity ecosystem model, coupled to a hydrodynamical model, can help assessing the skill of the physical ocean model in depicting realistically the prevailing mesoscale features of the upper layers of the Gulf of Mexico. Results indicate that the physical model effectively reproduces the mesoscale features of circulation underlying the resulting chlorophyll concentrations, especially when circulation fronts exist.

Abstract 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.

Specimens of Piscicola pojmanskae were identified in the macrozoobenthos community in Zostera meadows in Puck Bay. The presented paper is the first report on the observation of this species in the Gulf of Gdańsk (the southern Baltic Sea). Leeches are a rare component of the benthic fauna in this brackish water area.

In this work, data on methanogenic Archaea communities in sediment from the coastal area of Puck Bay were investigated. Sediments were collected along the Hel Peninsula from areas characterized by the occurrence of gas bubbles. Based on the analysis of molecular markers, the presence of a specific methanogenic Archaea gene was detected at all stations. Further research involved the cloning and sequencing of methanogenic DNA. Based on the comparison of obtained genetic sequences with existing genetic databases, it was confirmed that all of the nucleotide sequences belonged to the domain Archaea. Furthermore, in the investigated sediment certain sequences had certain similarities to the sequences of organisms from the families Methanosarcinaceae, Methanospirillaceae and Methanocorpusculaceae.

Abstract Extensive sampling (450 grabs) was performed all over the inner part of Puck Bay (105 km2 area) in summers of 2007–2009. The GIS-based analysis of samples was performed to assess in detail the distribution of 32 benthic species. The minimum area of occurrence was less than 1 km2 for Lekanosphaera rugicauda and the maximum was 83 km2 for Cerastoderma glaucum. The material reveals that species with the pelagic larval stage were most widespread, with the least distance between individuals and the highest average density (e.g. Cerastoderma glaucum, Hydrobia ventrosa). The most isolated and the least dense species within the studied area were discretely mobile, non-larval crustaceans (e.g. Gammarus oceanicus and Lekanosphaera rugicauda), present at single sites with the largest distance from each other. We conclude that analysis of species distribution helps in understanding the threats to populations of marine invertebrates and marine spatial planning, through locating the isolated species and populations.

An oceanic model and satellite data are used to evaluate the seasonal distribution of chlorophyll-a (Chl-a) in the Bay of Bengal (BoB) and Andaman Sea. Satellite data show high Chl-a concentrations because high Chl-a concentrations reduce CO2 and increase O2 at the sea surface, indicating fish abundance in the ocean. Sample collection alone cannot provide an accurate overview of Chl-a concentration over an entire region. The satellite data concerning Chl-a concentration, phytoplankton absorption coefficient, and Sea Surface Temperature (SST) are from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) project and from the Moderate Resolution Imaging Spectroradiometer (MODIS). The oceanic model is created to give the surface circulation as a result. The research finds that the simulation is in agreement with SST, Chl-a concentration, and phytoplankton absorption coefficients obtained from satellites. The conclusion is that the oceanic model can be used to implicitly explain the seasonal distribution of Chl-a in the Bay of Bengal and Andaman sea.

A total of 379 individuals of Eriocheir sinensis (198 males and 181 females) were captured in the Odra estuary (Poland). The crabs were thawed and their carapace length (CL), the maximum carapace width (CW) and the maximum height (CH) were measured. Measurements were also taken on each claw, the claw length (CHL1, the right claw; CHL2, the left claw), the width (CHW1 and CHW2 for the right and the left claw, respectively), and the height (CHH1 and CHH2 for the right and the left claw). For each crab, the wet weight was measured for each of the following body components: the whole crab (CrWe), the carapace (CaWe), the right claw (WRC) and the left claw (WLC). For females, the relationship between CL and CW, CH and CW were isometric, and for all linear measures, the relationship with CW was positively allometric. For males only this first relationship was isometric, but others were positively allometric. The differences between relative growth parameters for males and females were statistically significant.

Abstract Peat bogs are unique and important habitats for biodiversity at the species and ecosystem level where low pH of water plays a major role. The main objective of the present study was to compare the benthic diatom assemblage structure of the selected part of the Fenn’s and Whixall Mosses complex in order to verify whether selected sampling sites differ from each other. The complex is a cut-over, lowland raised mire, which is a National Nature Reserve (NNR) and a Site of Special Scientific Interest (SSSI). Altogether 92 diatom species were identified in 72 benthic samples collected between September 2008 and August 2009 from six selected sampling sites. Statistical cluster analysis was used to classify diatom samples and to observe the structure of diatom assemblages. The results of this analysis grouped the data set into 3 clusters with 24 samples from each of the two sampling sites in one cluster. Such a clear division shows that pH of water has an impact on the species composition, the richness and diversity of benthic diatom assemblages.