Volume 42 (2013): Issue 1 (March 2013)

The cyanobacterium Synechocystis aquatilis was observed growing as a monospecies in enriched phytoplankton samples in the laboratory, indicating its allelopathic activity on coexisting phytoplankton species. Therefore, the present study screened the culture medium of an axenic strain of this cyanobacterium for the presence of allelechemicals with algicidal properties by thin-layer chromatography (TLC). The allelopathic effect of S. aquatilis was evaluated by co-cultivation of target species of toxic cyanobacteria and green algae with this cyanobacterium, as well as by evaluation of norharmane (β-carboline 9H-pyrido(3,4-b) indole) crude extract prepared from the culture medium of Synechocystis. The growth of target algal species was measured as a cell density after 6 days incubation. The results showed that S. aquatilis produced the indole alkaloid norharmane with large quantities in the culture medium (86 μg l−1). In co-cultivation experiments, S. aquatilis inhibited the growth of all tested cyanobacteria and green algae. Norharmane crude extract exhibited stronger inhibition of cyanobacteria (EC50 = 4.6–4.8 μg ml−1) than green algae (EC50= 6.3–6.4 μg ml−1) in a concentration-dependent manner, indicating its apparent role in the allelopathic activity of S. aquatilis. The possible applicability of the allelochemical, norharmane, as an algicide to prevent the formation of harmful algal bloom was discussed.

The aim of this work was to develop an improved method for isolation and purification of genomic DNA from filamentous cyanobacteria. The method described here employs a modified phenol extraction-based procedure. It allowed us to obtain a high yield (60–620 μg/g wet weight, depending on the cyanobacterial strain) of pure and undegraded genomic DNA (A260/A280 ratio of about 1.8 and A260/A230 ratio of about 2.0). Genomic DNA, isolated from cyanobacteria belonging to the genera Anabaena, Nodularia and Nostoc has been successfully used for construction of gene libraries. Thus, this method can be used in procedures requiring highly purified cyanobacterial DNA.

Ciliate abundance and species composition were studied in the sandy beaches of six lakes of different trophic status (Poland). Samples of wet sand were taken in June 2007 from the euarenal (emergent sand), hygroarenal (sand wetted by lake waves) and hydroarenal (submerged sand) zones. The numbers of ciliates ranged from 105 to 2933 ind. cm−3 of sand and did not show any visible trend with lake productivity. In all the studied lakes, ciliates were much more numerous in the euarenal than in the hydroarenal. Small bacterivorous scuticociliates dominated in the euarenal, while Hymenostomatida, Cyrtophorida, Hypotrichida as well as Scuticociliatida comprised a significant part of the ciliate community in the hygro- and hydroarenal zones. There were positive correlations between ciliates and the concentrations of chlorophyll a and total nitrogen.

Macro-ionic composition of fish opercula may be an indicator of the fish stock identity. This is especially interesting in river estuaries, where individual sections of the estuary may differ in terms of their hydrochemical regimes. Diversified macro-ionic tissue composition is likely to provide clues not only about the origin of an individual fish, but also about its possible migration routes. The current study researched this aspect of the chemical composition of perch collected from different sections of the Oder River estuary. A total of 60 European perch, Perca fluviatilis L., were obtained from 3 sampling sites located in the river at Widuchowa, Szczecin Lagoon, and Pomeranian Bay, where waters are subject to dynamic macro-ionic transformations. Fish length ranged from 20 to 25 cm. Opercula of the fish were examined for their content of calcium, magnesium, strontium, sodium, and potassium, with the aid of the flame method using a Perkin-Elmer 3100 atomic absorption spectrophotometer. Perch inhabiting the waters of the Oder River between Widuchowa and Szczecin Lagoon had their opercula composed predominantly of calcium. Calcium was also the predominant ion dissolved in the water in this area; Ca represented 83.6% of all cations in the water and 41.6% of those present in the bones of the perch operculum. The increased levels of salinity near the sea were associated with the replacement of calcium in bones by other, more readily available elements (magnesium or strontium). Differences in the observed macro-ion composition of the opercula were sufficient to assign the perch studied to two distinct groups inhabiting fresh and brackish waters.

The physico-chemical water characteristics and basin morphology of 10 well-preserved Pomeranian peatland lakes were examined. These are acidic (pH 3.95–5.99), softwater (1.5 ±0.9 mg Ca dm−3), and oligotrophic water bodies. Their hydrochemical conditions differentiate them into two groups: poor (3.04 ±2.77 mg C dm−3) and rich (10.36 ±7.27 mg C dm−3) in organic carbon compounds. They differ in water colour (p = 0.02), humic acid concentration (p<0.001), redox potential (p = 0.007), and irradiance (PAR; p = 0.03).

The hydrochemistry of the lakes is determined by their basin morphology, which affects the water colour and the concentrations of humic acids and organic carbon compounds.

The present communication reports on the occurrence of a multi-species diatom bloom in the upwelled waters along the southwest coast of India. During the late summer monsoon season (September 2009) a multi-species diatom bloom with a pale green discoloration of the sea surface was observed in the coastal waters of southwest coast of India. The bloom spread over an area of approximately 15 km2 along the coastal waters off Kannur (Lat. 11°59.471 N, Long. 75°03.446 E). Total diatom cell density of the bloom area was 16 × 104 cells l−1. Proboscia (=Rhizosolenia) alata (Brightwell) Sandstrom constituted 90% of the total phytoplankton population. Other phytoplankton groups that contributed to the bloom population included Chaetoceros spp., Pseudo-nitzschia spp., Rhizosolenia spp., Coscinodiscus sp., Leptocylindrus danicus, Thalassiosira sp., and Bacteriosira sp. Among these Pseudo-nitzschia multiseries, a toxic species with the ability to produce potent neurotoxin domoic acid, was observed with a cell density of 4 × 103 cells l−1. Surface chlorophyll a concentration of the bloom region was 14.1 μg l−1. Nutrient concentrations of the bloom area were 0.01 μmol l−1 for NO2-N, 0.1 μmol l−1 for NO3-N, 0.83 μmol l−1 for PO4-P and 11.44 μmol l−1 for SiO4.

The species structure of epizoic communities of Rotifera was analyzed on three species of freshwater sponges: Spongilla fragilis Leydy, Spongilla lacustris (L.) Vejd. and Ephydatia fluviatilis (L.) Vejd. In total, all studied sponges hosted 87 rotifer species. Epizoic communities of Rotifera from particular sponges were very diverse, reach in species and unique. Thus, sponges covering both natural substrates and artifacts may create “hot-points” of rotifer species diversity and therefore may play an important role in re-naturalization of wastes.

The aim of this project was to study the fate of chemically persistent organochlorine xenobiotics in the marine link of the food web, between penguins and herrings (Clupea harengus), which are the only food for Spheniscus demersus from the Gdańsk Zoo. Concentrations of hexachlorobenzene (HCBz), pentachlorobenzene (PCBz), trichlorobenzene (TCBz) and the γ-HCH isomer were determined in Baltic herrings, in muscles, fat and liver of penguins, unhatched eggs, contour feathers and guano. The highest concentrations of fungicides were observed for HCBz. Fungicides were not detected in the liver of penguins and herrings. The bioaccumulation factor (BAF) for fungicides reached the highest values in the penguin brain. The highest biomagnification factor (BMF) for PCBz was determined in the muscle tissue and for lindane — in liver. It was confirmed that detoxification of penguins occurred through deposition of fungicides and lindane in guano and through epithelial tissue and eggs.

The annual variability of ichthyoplankton in the Yangtze River estuary, located at the junction of the East China Sea and the Yellow Sea, on the continental shelf at the western rim of the Pacific Ocean, was studied using vertical tows at twenty stations from August 2002 to August 2009. Basic oceanographic parameters such as temperature and salinity were also measured to evaluate their relationship to the abundance of ichthyoplankton. The eggs or larvae of a total of 34 fish species were present in the samples. Only 8 species were found to occur during every year. Engraulis japonicus and Stolephorus commersonii eggs, as well as Coilia mystus and Stolephorus commersonii larvae, were highly abundant during this period. Additionally, water storage in the Three Gorges Reservoir, which began in June 2003, had significant effects on the abundance of estuarine species, as well as on the composition and diversity of ichthyoplankton; this became evident when these values were compared to the findings from 2002. The number of species (species richness) and abundance of each species varied among the stations relative to the salinity in the estuary during the study period.

This article presents results of diatom analysis of seven sediment cores taken from various depths of the Gulf of Gdańsk between the Hel Peninsula and the coast of Gdańsk and Gdynia. Further eight cores were drilled in the northern, southern and central part of the Vistula Lagoon. The present investigations enabled the determination of: (i) differentiation of diatom assemblage zones, (ii) correlation of palaeoecological units with reference to the following stages: Mastogloia Sea, Littorina Sea, Post-Littorina Sea, including the latest environmental changes associated with an anthropogenic factor, (iii) description of the defined diatom biofacies based on statistical analysis, (iiii) reconstruction of spatial and temporal development of both basins with the emphasis on the role of inflows of sea and river waters.

The epilimnetic and metalimnetic phytoplankton assemblages were compared in two mesotrophic lakes (L. Hańcza and L. Dejguny, northeastern Poland) and a “metalimnetic niche” is described. Phytoplankton analysis conducted during July and August 2006, 2007, and 2008 indicated that the total phytoplankton biomass in both lakes was relatively small (from 0.6 to 5.2 mg dm−3), with maximum values mainly occurring in the metalimnion. The lowest number of species and diversity indices values were usually observed in the metalimnetic layers. Lake Hańcza was dominated by diatoms (e.g. Cyclotella spp.) whereas Lake Dejguny was mainly dominated by cyanoprokaryotes (e.g. Planktothrix agardhii), with a distinct predominance of diatoms (e.g. Tabellaria flocculosa) in 2007. The common features of the phytoplankton assemblages in both lakes were a tolerance to nutrient and light deficiencies. A cluster analysis of the taxonomic patterns indicated large dissimilarities between the lakes. The phytoplankton assemblages developed under the influence of seasonal conditions, especially in Lake Hańcza. The distinction between metalimnetic and epilimnetic phytoplankton assemblages only appeared in Lake Dejguny.

Elemental mercury re-emission into the air from an old burial ground in Gdańsk Letnica and from a modern landfill in Gdańsk Szadółki resulted in noticeably increased TGM concentrations from the urban background level of 1.9 ng m−3 to a maximum value of 164.4 ng m−3. Hgtot concentrations in the soil of the burial ground ranged from 37.3 to 4817.3 ng g−1 and in the surrounding water: from 22.0 to 55.0 ng dm−3. The highest Hgtot concentrations in the modern landfill (Gdańsk Szadółki) were reported for the unsorted waste: 36.1–972.8 ng g−1. Laboratory experiments on the re-emission of Hg(0) into the air showed that emission from soil was stimulated by solar radiation and from the water — additionally by turbulent mixing.

This mini-review discusses the occurrence of chemical pollutants in edible biota from European seas, including the Baltic Sea ecosystem. The bioaccumulation of organic and inorganic pollutants in marine fish and edible molluscs and crustaceans is briefly approached within the context of European Union (EU) food quality standards. The health risks associated with the human consumption of seafood have been assessed mainly by the European Food Safety Authority (EFSA), an independent European agency funded by the EU. The potential health risks arising from the consumption of “frutti di mare” are examined from the standpoint of estimated Provisional Tolerable Weekly Intakes (PTWIs) for toxic pollutants.

Researchers continuously search for adequate and inexpensive fish sampling methods and, as such, it is worth remembering the quantitative seine method with three identical nets hauled individually towards a stop net or a bank. A sample obtained by three nets is the absolute minimum for any accurate estimate employing a removal technique, and this procedure provides an estimate of density with a known error, because it allows for calculations of the variance value. Density (the number of individuals calculated from the model, as per defined area or volume), a popular term in the previous century when a secondary production and bioenergetics budget studies were considered to be modern investigations, but now when it is used with different meanings, an attempt has to be undertaken to sort out this terminology.