Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 32

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Mass occurrence of nuisance algal species Gonyostomum semen is observed in European humic lakes since 1970s, initially in the Scandinavian countries, then in eastern, central and western part of the continent. In 2002 mass appearances of this flagellate were found in three of 12 investigated humic lakes situated in the Eastern Poland. Lakes with Gonyostomum were situated within small geographical area. The biomass of algae was usually higher than 1 mg dm⁻³ and during summer its distribution was frequently uneven with higher values found in deeper layers. Based on this research we conclude, that G. semen during its spreading on the new area had preferred 6–8 m deep and small lakes with thermal and oxygen stratification as well as with low calcium content, slightly acidic to slightly alkaline pH and moderate color of water.
A new locality of Schoenoplectiella mucronata – an endangered and warm-temperature wetland species was found in Western Polesie (Eastern Poland). The new station is situated far away to the north-east from all known Polish sites and belongs to the easternmost one within European range of the species. The mesotrophic Lake Kleszczów in which we have found a new population of S. mucronata was characterised by a good ecological state as well as high diversity of aquatic plants dominated by a charophyte meadow. The studied species occurred in a phytocoenosis which is similar to a not known in Poland plant community Typho angustifoliae-Schoenoplectetum mucronati described from Hungary.
Mining activities affect a landscape in different ways, including by the formation of subsidence troughs, which after being inundated form wetlands and lakes. The development of new mining reservoirs may give a unique opportunity to study the early stages of colonization by various freshwater communities, including phytoplankton. Our paper presents the results of phycological research undertaken in newly formed subsidence reservoir near the coal mine “Bogdanka” (Polesie Lubelskie) a few months after its filling with water. The reservoir represented a unique, rare limnologic type due to the fact that it disappeared as a result of intended melioration works in the autumn of the same year. The study focused on morphometric measurements of the episodic reservoir, determination of general physicochemical parameters of water, and qualitative and quantitative structure of the phytoplankton community, was undertaken in five separated basins. A total of 80 algal taxa were determined. Most of them belonged to euglenoids (Euglenophyta-36) and green algae (Chlorophyta-26). Among euglenoids, most species were represented by Trachelomonas genus (14), while among green algae, most species were assigned to Scenedesmus genus (8). Several rare species were found, including: Scenedesmus bacillaris Gutw., Dinobryon petiolatum Willén, and Trachelomonas botanica Playfair. Green algae and euglenoids also had major contributions to the total phytoplankton abundance, which in all study sites did not exceed 2.2×10⁶ ind.·dm⁻³. This phytoplankton structure was probably influenced by the high water color related to particular and dissolved organic matter from pre-existing alder forests. Some differences in phytoplankton structure found among sampling sites were probably connected with habitat differentiation in terms of exposure to light.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.