Stojące i płynące wody Poznania

Książka zawiera 139 stron, 153 barwne fotografie oraz 135 pozycji literaturyZamiarem autorów tego opracowania było zebranie i przybliżenie czytelnikowi podstawowych wiadomości o jak największej liczbie zbiorników i cieków wodnych, znajdujących się w granicach administracyjnych Poznania. Do przedstawionych danych należy przede wszystkim położenie zbiorników, przebieg cieków wodnych, ich cechy morfometryczne, ale również tam, gdzie to było możliwe – informacje o walorach przyrodniczych, turystyczno-krajobrazowych i o jakości wody. Mają one zachęcić mieszkańców Poznania do odwiedzania opisanych miejsc w ramach wycieczek, spacerów czy choćby po to, by odpocząć od zgiełku ulic miasta i trudów pracy zawodowej. Mają również rozbudzić zainteresowanie otaczającą przyrodą młodzież szkolną, będąc uzupełnieniem wiedzy zdobywanej w ramach zajęć szkolnych.Wydanie książki dofinansowano ze środków budżetowych Miasta Poznani

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe

Mass development of phytoplankton in the River Warta in Poznań (Poland) in the 21st century

The first studies of phytoplankton of the River Warta in Poznań (Poland) were carried out in the 20th century (in 1922–23 and 1950–57). In the growing seasons the dominant groups were diatoms and green algae. Cyanobacteria were noted, but they did not have high abundance. The aim of this work is to present the phytoplankton research conducted on the River Warta in Poznań in the 21st century (in 2003, 2009, 2010 and 2016). In all years the dominance of diatoms and green algae in terms of biomass was noted. However, in late summer cyanobacteria biomass was high and this group became dominant or co-dominant. Spring blooms were created by unicellular centric diatoms, e.g. Stephanodiscus minutulus and colonial green algae: Coelastrum microporum or Micractinium pusillum. In summer, bloom-forming taxa were unicellular centric diatoms, colonial diatoms: Aulacoseira granulata or Fragilaria crotonensis and cyanobacteria: Aphanizomenon flos-aquae and Woronichinia naegeliana. The occurrence of taxa typical of dam reservoirs and lakes suggests the influence of the Jeziorsko Reservoir on the phytoplankton of the River Warta, but it does not exclude the impact of tributaries and oxbow lakes. The research conducted in the 20th and 21st century show important changes in the taxonomical structure and abundance of phytoplankton

Toxic Picoplanktonic Cyanobacteria—Review

Cyanobacteria of a picoplanktonic cell size (0.2 to 2.0 µm) are common organisms of both freshwater and marine ecosystems. However, due to their small size and relatively short study history, picoplanktonic cyanobacteria, in contrast to the microplanktonic cyanobacteria, still remains a poorly studied fraction of plankton. So far, only little information on picocyanobacteria toxicity has been reported, while the number of reports concerning their presence in ecosystems is increasing. Thus, the issue of picocyanobacteria toxicity needs more researchers’ attention and interest. In this report, we present information on the current knowledge concerning the picocyanobacteria toxicity, as well as their harmfulness and problems they can cause

Pionowe rozmieszczenie aldehydów a struktura fitoplanktonu : studium przypadku jeziora miejskiego

In water systems, both biologically and chemically synthesized molecules may reduce environmental quality and influence essential ecosystems structure and function. These substances include aldehydes from various sources, also those relates to the activities of primary producers. The focus of the study was vertical distribution of several aliphatic aldehydes and phytoplankton biomass in an urban lake in Poznań (Wielkopolska Lakeland, Poland) under human pressure. Water samples were collected from surface lake to bottom, every 2 m. Plankton was analyzed under inverted and epifluorescence microscopes. The biomass was estimated from microscopic measurements and cell volume of each species. Thirteen aldehydes and acetone were analyzed using gas chromatography with an electron capture detector after derivatization and extraction processes. Aldehydes concentrations varied between 32.7 and 346.2 μg L-1. Formaldehyde, acetaldehyde and propanal were characterized by the highest concentration both at low and high phytoplankton biomass. Phytoplankton biomass included prokaryotic and eukaryotic cells, and ranged between 0.25 and 2.94 mg L-1. Cryptophytes and diatoms were often the most important components of phytoplankton communities, although in some cases the haptophytes and dinophytes comprised a much higher proportion. Total aldehyde concentration was significantly correlated with total phytoplankton biomass (r=0.705, p <0.05), and even higher correlation was observed between acetone and phytoplankton biomass (r=0.917). This indicates phytoplankton as an important source of carbonyl compounds in surface waters. Thus, the knowledge of different aspects of their origin and distribution in the lake is important both in ecological research and in water management.W systemach wodnych, zarówno biologicznie jak i chemicznie syntetyzowane cząsteczki mogą obniżać jakość środowiska i wpływać istotnie na strukturę i funkcjonowanie ekosystemów. Substancje te obejmują aldehydy pochodzące z różnych źródeł, również te związane z aktywnością producentów pierwotnych. Przedmiotem badań było rozpoznanie pionowego rozmieszczenia kilku aldehydów alifatycznych i biomasy fitoplanktonu w jeziorze miejskim w Poznaniu (Pojezierze Wielkopolskie, Polska) znajdującym się pod presją człowieka. Próbki wody pobierano od powierzchni jeziora do dna, co 2 m. Plankton analizowano pod mikroskopem odwróconym i epifluorescencyjnym. Biomasę oszacowano na podstawie pomiarów mikroskopowych i objętości komórek każdego gatunku. Trzynaście aldehydów i aceton analizowano za pomocą chromatografii gazowej z detektorem wychwytującym elektrony po procesach derywatyzacji i ekstrakcji. Stężenia aldehydów wahały się od 32,7 do 346,2 μg L-1. Formaldehyd, aldehyd octowy i propanal charakteryzowały się największym stężeniem zarówno przy niskiej, jak i wysokiej biomasie fitoplanktonu. Biomasa fitoplanktonu obejmowała komórki prokariotyczne i eukariotyczne i mieściła się w przedziale od 0,25 do 2,94 mg L-1. Kryptofity i okrzemki były często najważniejszymi składnikami zbiorowisk fitoplanktonu, choć w niektórych przypadkach większy udział miały haptofity i dinofity. Ogólne stężenie aldehydów było istotnie skorelowane z całkowitą biomasą fitoplanktonu (r=0,705, p <0,05), przy czym jeszcze silniejszą korelację zaobserwowano między acetonem i biomasą fitoplanktonu (r=0,917). Wskazuje to na fitoplankton jako ważne źródło związków karbonylowych w wodach powierzchniowych. Tym samym wiedza o różnych aspektach ich pochodzenia i rozmieszczenia w jeziorze jest ważna zarówno podczas badań ekologicznych, jak i w gospodarce wodnej

Seasonal Variation of the Calcifying Green Alga Phacotus Lenticularis (Ehrenb.) Stein in Water Bodies under Human Influence (Mid-Western Poland)

The unicellular flagellates of the genus Phacotus, which form a solid calcite lorica by extracellular precipitation of calcium carbonate are some of the nanoplankters quite frequently occurring in hardwater ecosystems of the temperate zone. The aim of this study was to describe seasonal changes of Phacotus lenticularis populations in several types of water bodies (a glacial lake, small and shallow ponds, and a lowland river) in relation to some environmental parameters. All the water bodies are subject to multiple human pressure: recreation, fishing, agriculture, and urbanization. P. lenticularis individuals preserved in Lugol’s solution were counted under an inverted microscope (after sedimentation in 14 or 9 ml chambers), including both empty and filled loricae. Its populations differed both between seasons and between waters. High P. lenticularis abundance was mainly limited to the summer months. It was observed at temperatures above 19°C and pH values above 7.8, in water characterized by quite high electrolytic conductivity (>500 μS cm-1). Statistical analysis reveals two significant relationships between physicochemical parameters and the abundance of P. lenticularis. This suggests that in the investigated waters the biotic factors and processes are probably more important regulators of changes in the density of its population than nutrients

The Effect of Human Impact on the Water Quality and Biocoenoses of the Soft Water Lake with Isoetids: Lake Jeleń, NW Poland

Soft water lakes with isoetids (SLI) are ecosystems prone to degradation due to the low buffer capacity of their waters. One of the main threats resulting from human impact is eutrophication due to agriculture, catchment urbanization and recreational use. In this paper, changes in the water chemistry and transformation of biocoenoses of one of the largest Polish SLI, Lake Jeleń, over the past 30 years are presented. The lake is located within the borders of a city, and a significant part of its catchment is under agriculture and recreation use. The physicochemical (concentration of nutrients, organic matter, electrical conductivity, oxygen saturation and water pH) and biological parameters (macrophytes and phytoplankton) were measured in summer 1991, 2004, 2013 and 2018. Since the beginning of the 1990s, a gradual increase in the trophy of the lake has been observed as indicated by increased nutrient availability, deterioration of oxygen conditions and a decrease in water transparency. The alterations of water chemistry induce biological transformations, in particular, an increase in phytoplankton abundance (4-fold increase of biomass in epilimnion) as well as a gradual reduction in the range of the phytolittoral (from 10 to 6 m), a decrease in the frequency of isoetids, Lobelia dortmanna and Isoetes lacustris, and expansion of plant species characteristic for eutrophy

Some aspects of the ecological niche of chironomids associated with submersed aquatic macrophytes in a tailwater

High values of chironomids' production were recorded and analysed in the tailwater of a dam reservoir located on a large river. The values resulted from submersed aquatic macrophytes (SAM) patches that appear on the bottom in summer, as an effect of a specific discharge pattern through the dam. Abundant and taxonomically rich chironomid assemblages develop there, but their populations display different spatial and trophic preferences, which are the main topic of our interest here. We focused on dominant taxa of Orthocladius/Cricotopus spp., Chironomus riparius Meigen and Glyptotendipes cauliginellus (Kieffer), whose abundance and biomass exceeded 90% of all chironomids inhabiting the SAMs. The developmental time of their aquatic stages (cohort production interval − CPI) and thus production, and production to biomass ratio (P:B) differed considerably. A P:B ratio of 13.8 was estimated for the first taxon, a mid-body size scraper living on stems and leaves of SAMs. In contrast, P:B ratios of 5.2-7.7 were assessed for the second and third taxa, rather large body size benthic gathering collectors inhabiting the roots of SAMs. The main food categories of gathering collectors were particulate organic matter trapped by the roots, while scrapers fed on algae developing on leaves and stems

Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer

To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L-1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4 degrees C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature.Peer reviewe