Since 2005, great cormorants have been observed on the Lake Góreckie (Wielkopolski National Park) shoreline. The population of these birds occurring within the lake has gradually increased. In autumn 2008, more than 100 individuals were observed. In the period 2009-2012 the number of birds occupying the island periodically exceeded 250 individuals. So far, there is no breeding colony of great cormorants, but the birds have established a roosting colony on the island. In the period 2009-2012 we conducted research on the impact of the colony of great cormorants on the accumulation of nitrogen, phosphorus and other elements in soils beneath the colony and transfer of chemical elements from the colony to a nearby freshwater ecosystem. Our results show that a relatively small and recent colony of great cormorants can significantly affect the chemistry of soil. Compared to a control, the soil beneath the colony was characterized by statistically higher concentrations of nitrogen and phosphorus. A significant accumulation of nutrients was observed in the topsoil zone (to a depth of about 20 cm). Enrichment of soil in chemical elements has resulted in their further transport to a nearby lake. Compared to the control, the groundwater and surface runoff from the colony area revealed several-fold higher concentrations of nitrogen and phosphorus. The maximum abundance of cormorants in the roosting colony was reflected in the elevated concentrations of nitrogen and phosphorus in the littoral water near the colony. Our study demonstrates that the roosting colony of great cormorants can play a significant role in accelerating the eutrophication of surface waters.
During 2009-2011 we investigated the effect of perennial and roosting cormorant (Phalacrocorax carbo sinensis) colonies on microbial pollution in 3 lakes: Góreckie (Greater Poland National Park), Chrzypsko (Greater Poland Province) and Ostrowiec (Drawa National Park). On Lake Góreckie cormorants formed a roosting colony (<200 individuals) that inhabited part of the lake shore. On Lake Chrzypsko a new breeding colony was formed (3 nests) while the breeding colony on Lake Ostrowiec, established over 40 years ago, consisted of over 170 breeding pairs. In the case of Lake Ostrowiec, high pollution with coliform bacteria (including Escherichia coli) was observed. Compared to the control station the significantly higher Most Probable Number (MPN) of coliform bacteria was found in groundwater under the colony. It was found that bacterial counts decreased in the direction of the centre of the water body with the highest numbers noted in the lake samples collected within the colony boundaries. Furthermore, seasonal variations in coliform bacteria were also observed with maximum densities during the breeding season. Similar trends were observed for the roosting colony on Lake Góreckie while for the newly forming colony on Lake Chrzypsko increased density of investigated bacteria was noted only in groundwater.
Municipal water reservoirs improve urban landscape architecture, providing water for various domestic uses. At the same time, they are under strong human impact affecting water quality and biological conditions. We investigated the level of metal accumulation (Cd, Co, Cr, Cu, Fe, Ni, Mn, Pb and Zn) in sediments as well as mussels Anodonta anatina and Unio tumidus and common reed Phragmites australis collected from 8 sampling sites at Malta Reservoir (Poznań, Poland) just before the complete drainage of the lake in November, 2012. In all investigated samples metal concentrations ranked in decreasing order: Fe>Mn>Zn>Cu>Cr>Ni>Pb>Co>Cd. Accumulation of toxic metals in roots of P. australis was higher than in soft tissues of mussels although it did not exceed phytotoxic levels. Roots of P. australis accumulated high levels of Cr (mean 9.7 μg g-1) and Ni (mean 5.7 μg g-1). U. tumidus accumulated higher concentrations of Cr (mean 1.1 μg g-1) than A. anatina indicating potential use in bioindication of this metal. The present study provides the most recent information on metal content in sediments and biota in Malta Reservoir and, further, suggests that this reservoir is capable of accumulating toxic elements from preceding water bodies (Lake Swarzędz) and surrounding residential areas.
The non-selective, post-emergence herbicides based on glyphosate [N-(phosphonomethyl) glycine] are one of the most widely used pesticides in agriculture, urban areas and forestry. Although there has been documentation on the physical, chemical and toxicological properties of glyphosate, the aquatic toxicity of such formulations still requires assessment and evaluation. In the present study, we describe deliberate use of glyphosate-based herbicide in a bathing area of Lake Lednica (Wielkopolska, Poland) by unknown perpetrators in April, 2011. Glyphosate was detected using gas chromatography mass spectrometry (GC-MS) in the water samples collected from the bathing area at a mean concentration of 0.09 mg dm-3. Aboveground parts of emerged macrophytes (Phragmites australis and Typha latifolia) covering the investigated area were completely withered. Studies of benthic macroinvertebrates revealed no significant differences in taxa number between event (13 taxa) and control (14 taxa) sites although differences in abundance of particular taxa were observed. Significantly lower numbers of Chironomidae (by 41%), Oligochaeta (by 43%), Vivipariae (by 75%), Hirudinae (by 75%), Asellus aquaticus (by 77%), Gammarus pulex (by 38%) and Dreissena polymorpha (by 42%) were found at the glyphosate-treated site. Furthermore, compared to the control, chironomids (Chironomidae) exposed to glyphosate were represented by specimens smaller in length while A. aquaticus only showed large adults. The ranges of glyphosate concentration in the tissues of sampled macroinvertebrates and Phragmites australis organs were 7.3-10.2 μg kg-1 and 16.2-24.7 μg kg-1, respectively. Our study indicates that glyphosate-based herbicides may have adverse effects on aquatic organisms including macroinvertebrates, thus their use in (or nearby) surface waters should be subject to strict limitation.
The global use of pharmaceuticals is on the systematic rise and leads to contamination of surface waters with xenobiotic compounds with a wide range of bioactivity. Waters that receive urban and medical effluents are particularly threatened. The presence of pharmaceuticals in these ecosystems can lead to unpredictable ecological impacts and responses, and may also have an impact on human health. At the same time the identification and quantification of these chemicals, to a large extent remains a subject to scientific investigation than part of a thorough monitoring programme. Their biological effects on aquatic organisms are mainly recognized experimentally and often using concentrations far exceeding environmentally relevant levels. This review paper defines the main sources of pharmaceuticals in the aquatic environment, discusses the fate of these compounds and summarizes the current state-of-the-art of pharmaceutical monitoring in Polish surface waters.
Urban reservoirs can receive high loads of chemicals, including persistent contaminants and eutrophication-promoting nutrients. To maintain their economic and recreational use, implementation of various restoration methods is often required. The Maltański Reservoir (Poland, Europe), a small, shallow and dammed urban water body, undergoes complete draining every four years as part of its restoration procedure. Here, we investigated the phosphorus (P) content and its fractions just before the reservoir was drained and after it had been completely filled with water again. As demonstrated, the highest accumulation of P occurred at sites through which the main water flow is directed. Calcium-bound and residual P constituted the largest proportion of P fractions. A shift in P fractions after the reservoir was drained and sediments were left without water for at least 4 months was observed. A decrease in phytoplankton utilized NH4Cl-P, Fe-P and NaOH-P fractions was found and followed a simultaneous increase in nearly biologically inaccessible HCl-P and practically biologically inactive residual P fractions. Our study demonstrates that complete drainage of the Maltański Reservoir may additionally decrease the risk of internal P loading through shifts in its fractions.
Cylindrospermopsis raciborskii which belongs to the order of Nostocales has continuously been at the centre of interest of various research groups owing to its great ecological plasticity, wide distribution and potential to produce different metabolites known to be harmful for humans and animals. Over recent decades, Polish strains of C. raciborskii have also been studied with regard to these issues. The present paper is a brief review of the present state of knowledge respecting the occurrence and toxicity of this species with emphasis on Polish strains, and indicates potential directions for future research.
Flow cytometry (FCM) is routinely used in medical and veterinary diagnostics although it is also widely applied in environmental studies, including phytoplankton investigations. Cyanobacteria are wide-spread photosynthetic microorganisms that attract attention due to their ecology and potential toxicity. Therefore, novel research tools are being applied in their investigation. This paper characterizes FCM as a technique that enables photopigments (chlorophylls and phycocyanin) expressed by cyanobacteria to be excited and their emission to be subsequently detected. This feature not only allows cells to be counted in a rapid manner but also enables a wide range of potential applications in ecological and biochemical studies. The main advantages of FCM, such as rapid, automatic and precise measurements requiring small sample volumes, are also discussed in this paper along with challenges including analyses of filamentous cyanobacteria and signal overlapping. It is expected that FCM will continue to be used in some fields of cyanobacterial studies.