Ciliates on the macrophytes in industrially heated lakes (Kujawy Lakeland, Poland)

The ciliate assemblage on the macrophytes was examined in 2005 during the vegetation period in the Konin2skie Lakes which are heating by post-cooling waters from thermal electric plants. As a result of changed temperature regimen the alien thermophilic macrophyte Vallisneria spiralis is becoming increasingly common in the littoral zone. A total of 150 ciliate taxa belonging to 27 orders were found. Greater ciliate species diversity was found on architecturally complex, submerged forms such as Ceratophyllum demersum and Myriophyllum spicatum. By contrast the ciliate compositions on emergent macrophytes with simple architecture in their submerged parts, such as Typha, Sparganium, or Acorus, were less species rich. Despite the simple architecture of Vallisneria leaves, the ciliate diversity on them was high. The results show that replacement of native macrophytes by the alien form V. spiralis in heated lakes did not impoverish the ciliate diversity.В течение вегетационного периода 2005 г. изучали ассамблею ресничных простейших на макрофитах в Конинских озерах, подверженных тепловому загрязнению, которое вызвано поступлением подогретых вод с теплоэлектростанции. Вследствие изменения температурного режима водоемов, в их литорали доминирующее положение среди макрофитов занял адвентивный вид Vallisneria spiralis. Всего на макрофитах было зарегистрировано 150 таксонов ресничных простейших, относящихся к 27 отрядам. Большее разнообразие видов ресничных простейших обнаруживалось на пространственно сложноорганизованных поверхностях таких макрофитов, как Ceratophyllum demersum и Myriophyllum spicatum. На макрофитах с простой архитектурой, таких как, например, Typha, Sparganium и Acorus, количество видов было меньшим. В то же время, несмотря на простую архитектуру листьев Vallisneria, разнообразие ресничных простейших на них было высоким. Таким образом, вытеснение аборигенных макрофитов адвентивным видом V. spiralis в условиях подогретых озер не приводило к снижению разнообразия ресничных простейших

Morphological variability of oospores of Chara baueri A.Braun [Characeae]

The shape and size of present-day specimens of Chara baueri are described. C. baueri is believed to have practically died out in Europe. Oospores of specimens of C. baueri collected in Kazachstan were subjected to morpholgical analysis. Data recorded included oospore length, oospore diameter, the ratio of length to diameter, the number of lateral convolutions, ridge width, the width of the fossules at the equator, and the diameter of the basal pore. Variation in oospore length and the number of convolutions was higher than had been previously reported in the literature, whereas variation in oospore width was identical to previous reports

Baseline Water Temperature: Estimation of the Annual Cycle of Surface Water Temperature in Lakes in North-Central Poland over the 1951–1968 Period

Water temperature is an important ecological variable that affects the functioning of lakes. Unfortunately, for many lakes there are no long-term observations enabling the assessment of changes in water temperatures. This makes it difficult to include this aspect in research into the biology, ecology and chemistry of such lakes. This paper presents a literature review related to changes of surface water temperatures in lakes and in particular describing the response of water temperatures and stratification to changing climate in Polish lakes. On this basis, a model based on the available data on water temperature in 931 Polish lakes in the years 1951–1968 was proposed, which allows to estimate the baseline water temperature on any day of the year. This model is calculated using the complementary error peak function on the 0–3 m water temperature dataset, which provides the best reduction of diurnal temperature fluctuations. It can be an alternative to the average temperature of surface waters, which are calculated on the basis of systematically collected data. Based on the average water temperature data obtained from 56 thermal profiles in 10 lakes in 2010–2019, the equation was analogically calculated. The average monthly water temperatures in June, July, August and September and the change in water temperature (0.24–0.30 °C decade−1) in the period 1951–1968/2010–2019 were estimated then. Similar regional or single lake trends have been found in studies by other authors covering a similar or longer period of time. The proposed method, which is suitable for simulating temperatures, especially in summer, enables the determination of the value of changes in surface water temperature in Polish lakes when only thermal profiles data from different dates are available, which can be especially helpful when analyzing hydrobiological results

A Retrospective Ecological Status Assessment of the Lakes Based on Historical and Current Maps of Submerged Vegetation—A Case Study from Five Stratified Lakes in Poland

This article presents and tests a new method for the retrospective assessment of ecological status assessment of the lakes in accordance with the Ecological State Macophyte Index (ESMI), which is formally used in biological monitoring in Poland. The proposed method is based on three metrics, the Z colonization index, the average maximum depth of lake vegetation Cmax, and the Secchi disk depth. Mathematical functions of ecological class were developed on the basis of the mean values of these three indicators in summer for different ecological status classes in 88 stratified lakes in northern Poland and the Łęczyńsko-Włodawskie Lake District and five lakes in the catchment area of the Wel River (published data). The new metrics were validated on the basis of literature data—ESMI, Cmax, Z and SD values from 11 lakes near Olsztyn (Poland). The obtained results are similar to those calculated based on macrophyte field surveys and can be an alternative of the Ecological State Macophyte Index (ESMI), which is formally used in biological monitoring in Poland. The proposed method makes it possible to compare long-term changes in the ecological state of lakes, because it enables an analogous assessment on the basis of data calculated from historical bathymetric maps showing the distribution of hydro macrophytes (parameters Z and Cmax) as well as contemporary data, collected, among others, during hydroacoustic research

Morphological variability of oospores of Chara baueri A. Braun (Characeae)

The shape and size of present-day specimens of Chara baueri are described. C. baueri is believed to have practically died out in Europe. Oospores of specimens of C. baueri collected in Kazachstan were subjected to morpholgical analysis. Data recorded included oospore length, oospore diameter, the ratio of length to diameter, the number of lateral convolutions, ridge width, the width of the fossules at the equator, and the diameter of the basal pore. Variation in oospore length and the number of convolutions was higher than had been previously reported in the literature, whereas variation in oospore width was identical to previous reports

Changes in the quantitative relations of the phytoplankton in heated lakes

Abstract. Long-term changes in phytoplankton biomass and structure were studied in three heated lakes that were included into a power plant cooling system in 1958 and 1970. Since the mid 1990s, the share of Vallisneria spiralis L., which is a thermophilic hydrophyte species that is alien to Poland, has been increasing. The phytoplankton biomass fluctuated in these basins in the 1992-2003 period from 0.2 to 49.3 mg dm -3 . Two phytoplankton assemblages were noted: one was typical of the cold season and the other of the warm season. The phytoplankton in the summer comprised cyanophytes, chlorophytes, dinoflagellates, and cryptophytes. Diatoms developed on a massive scale during cold periods. The results obtained indicate that the contemporary phytoplankton assemblages are shaped by the varied impact of water heating, increased flow rates, the highly productive waters, and the developing submerged hydrophyte phytocenosis along with the abundant growth of the epiphyte assemblage

The physicochemical background for the development of potentially harmful cyanobacterium Gloeotrichia echinulata J. S. Smith ex Richt

This study focused on site-specific preferences of potentially harmful cyanobacterium Gloeotrichia echinulata to occur in lakes with different ecological and trophic conditions. Its pelagic growth was studied in six lakes from June to September in 1986-1988, 2000-2001 and 2009. In total, 78 samples were taken from the epilimnion (stratified lakes) or the whole water column (non-stratified lakes). Analyses of phytoplankton and environmental variables were performed according to standard methods. During summer, a distinct maximum of the Gloeotrichia growth was observed in July or August (the warmest period). Bloom events of G. echinulata occurred in lakes where the light and oxygen conditions were significantly inferior while the phosphorus content remained on a slightly elevated level. The distinct domination of this cyanobacterium (above 40% of the total phytoplankton biomass) was limited to lakes with a high, moderate or even poor ecological status, and to the meso-eutrophic or eutrophic state of lakes. However, G. echinulata occurred in a broader range of ecological and trophic conditions of lakes. The historical approach to mass occurrence of G. echinulata, with its possible contribution to phosphorus translocation from sediment to the pelagic zone, suggested its importance as an indicator of progressive ecological and trophic deterioration of lakes. This indication should be very useful for establishment of main targets in water management