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

Defensive behaviours and adaptations of amphibians

The Amphibians are specific group of animals, which is able to live as in water as on land. They are characterized by different physiology than other vertebrates. During the ages of evolution this apparently defenceless group of vertebrates developed many adaptations, which allow them to survive predation of other animals. Anti-predator mechanisms of amphibians in many cases are combined with skittishness, avoiding of beeing noticed or escape. However many of this animals are toxic and chracterized by an aposematic coloration, which is an warning to predator. Amphibians developed many defensive postures and behaviours, which sometimes are an answer to definite predator. Very often few mechanisms are combined together and guarantee amphibians survival.Gromada płazów jest specyficzną grupą zwierząt, mogącą żyć w zarówno w środowisku wodnym jak i lądowym. Charakteryzują się odmienną fizjologią od innych grup kręgowców, zarówno niższych jak i wyższych. W toku ewolucji, ta na pozór bezbronna grupa zwierząt wytworzyła szereg przystosowań pozwalających jej przetrwać wśród innych kręgowców, często będących dla niej zagrożeniem. Sposoby obrony płazów przed drapieżnikami w wielu przypadkach wiążą się z płochliwością, uniknięciem wykrycia i ucieczką. Jednak wiele z tych zwierząt charakteryzuje się toksycznością a także jaskrawym ubarwieniem, stanowiącym ostrzeżenie dla drapieżnika. Płazy wykształciły także różnego rodzaju postawy i zachowania obronne, często wysoko wyspecjalizowane i skierowane przeciw konkretnemu drapieżnikowi. Wszystkie te mechanizmy, niejednokrotnie łączące się ze sobą gwarantują płazom przetrwanie

Vegetation influence on inanimated nature of Ojców National Park

Sukcesja roślinności i ekspansja zbiorowisk leśnych po utworzeniu Ojcowskiego Parku Narodowego doprowadziła do znaczących zmian w krajobrazie Doliny Prądnika. Główną przyczyną tych zmian było zaprzestanie wypasu zwierząt gospodarskich. Zasłonięte zostały charakterystyczne elementy rzeźby terenu, które nadają temu miejscu szczególnych walorów estetycznych. Wegetacja przyspiesza również tempo wietrzenia skał. Władze Ojcowskiego Parku Narodowego podjęły działania mające na celu poprawę ekspozycji niektórych masywów skalnych. W pracy poruszony został problem zarastania form skalnych, na skutek zmiany sposobu gospodarowania ziemią po utworzeniu parku narodowego. Na podstawie porównania archiwalnych i aktualnych fotografii przedstawione zostały zmiany zespołów roślinnych porastających badane obiekty w XX wieku. Ukazany został wpływ wegetacji na krajobraz oraz na same skały.Succesion of vegetation and expansion of forests after establishing of the Ojcowski National Park caused significant changes of landscape of the Prądnik Valley. The main reason of this changes was the stop of grazing of live-stack. Characteristic elements of landscape which are very important as an estetique values were covered by vegetation. Another consequence of this process was intensification of weathering. Authorities of the Ojcowski National Park has undertaken actions that have to improve exposition of rocks. Problem of expansion of vegetation was descibed in this thesis. Basing on the comparison of archival and actual photos, there was shown changes in vegetation growing at examined study sites. Influence of vegetation on landscape and rocks were shown

The influence of climate factors on the presence of microcystins in freshwaters – a case study from Poland

Climate changes are expressed as increase of temperature and the frequency and intensity of severe weather conditions. Furthermore, climate change promotes development of bloom-forming cyanobacteria and the increase the intensity and toxicity of the blooms. According to European Environmental Agency (EEA), Europe is the fastest warming continent and particularly high warming is found over eastern Europe. The last six years were recognized as the warmest on record. However, the greatest changes will be possible to identify locally. We conducted the short-term surveys of concentrations of microcystins, which are recognised as the most often produced cyanotoxins, in two shallow and small water bodies in southern Poland. Data was collected during four years of monitoring: 2017, 2019-2021. We hypothesised that microcystin concentration is related to weather conditions. The pattern of microcystins distribution during the seasons were similar in both of them: toxins were present from July to October. Statistical analyses showed that significant factor correlated with concentration of microcystins was rainfall higher than 2.2 mm. Besides, stepwise regression demonstrated that rainfalls and air temperatures were significant contributors for dimensions PCAI and PCAII, which cumulatively explained 53% of varianc

Interactions between ciliate species and Aphanizomenon flos-aquae vary depending on the morphological form and biomass of the diazotrophic cyanobacterium

Aphanizomenon flos-aquae can form extensive blooms from freshwater to the brackish environment and, being a diazotrophic species, contribute significantly to the nitrogen and carbon cycle. It occurs as single filaments or aggregates and could be used as an alternative nutrients source for bacteria and ciliates. Ciliates are a group of organisms playing a crucial role in the transfer of nitrogen from primary producers to higher trophic levels in aquatic food webs. The aim of the experiment was to study the effects of the cyanobacterium A. flos-aquae on the community of five ciliate species (Spirostomum minus, Euplotes aediculatus, Strobilidium sp., Vorticella sp. and Paramecium tetraurelia). The response of each species to the presence of a low/high cyanobacterial biomass and to the different morphological forms of A. flos-aquae (single filaments or aggregates) was demonstrated. The results of the experiment showed the variability of interactions between the cyanobacterium A. flos-aquae and ciliates and pointed out the possible benefits that A. flos-aquae provides to the ciliates (e.g., a substrate for the development of bacteria as food for ciliates or as a source of nitrogen and carbon)

Developing an UAV method of monitoring of cyanobacterial blooms in freshwater ecosystems

Cyanobacterial blooms are widespread phenomenon naturally occurring in different types of water bodies. Characteristic indicator of the bloom is a change of water color to blue-green, due to pigments contained by growing cyanobacterial biomass. Recently observed climatic changes and increase of Earth’s surface temperature may lead to intensification and proliferation of cyanobacterial blooms, severe reduction of water quality and changes in functioning of freshwater ecosystems. Monitoring of cyanobacterial blooms appears to be crucial in order to undertake remediation policy, such as biomass harvesting. The aim of our study was to develop an index for cyanobacterial blooms detection with use of unmanned aerial vehicles (UAV). The data was collected from 30 frames floating on the surface of blooming waterbody. First, the reflectances inside the frames were measured by UAV equipped with multispectral camera, then immediately the and phycocyanin concentrations inside frames were measured in situ with use of multiparameter probe. Further statistical analyses allowed to create an index based on Red Edge 740 nm and 717 nm and NIR 842 nm spectral bands. The correlation of the index with phycocyanine concentration measured in situ was estimated as +70%

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

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°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