Mikroszkopikus algáink jelentősége és lehetséges alkalmazása a környezetpedagógiában

Mikroszkopikus méretű algáink számtalan jelentőséggel bírnak. Nekik köszönhetően nyomon tudjuk követni vizeink ökológiai állapotát, így teljes figyelmet és védelmet biztosítva legértékesebb kincsünknek, a víznek. Jelen cikk célja, hogy a limnológiai és hidrobiológiai témakörökre felhívja a figyelmet és népszerűsítse azok használatát a közoktatásban

Beta-diversity and structuring forces of diatom communities in small lakes of the Carpathian Basin

Investigating the dynamics beyond the patterns (structure, diversity) of microbial communities at regional level in different spatial scales has been a developing area in ecology and studies on diatoms with such approach receive increasing scientific interest. In this study, phytobenthos samples were collected from 41 lakes (<7 km2) in the Carpathian Basin in August 2010 and physical and chemical parameters were also determined simultaneously. Our aim was to quantify the regional species pool (γ-diversity), the local species richness (α-diversity), the dissimilarity among diatom communities (β-diversity) and to assess whether β- diversity is supported by species replacement or richness differences (nestedness). Furthermore, we investigated the local contribution to β-diversity (LCBD) of our sampling sites and that which factors play a key role in establishment of β-diversity. In the study region, we experienced high γ- (a total of 302 diatom species) and α-diversity (average species richness of 45±13). The diatom community was characterised by high β-diversity (> 0.93 multiple-site Sørensen dissimilarity) which was explained mainly by species turnover. Although deterministic processes were more decisive based on null model analyses, stochasticity can also take part in community assembly. The degree of β-diversity (and thus assembly of communities, as well) was related significantly to the local environmental variables, especially to TP content and to the geographical distance between samplig sites. Samples from Kun-Fehér-tó, Pirtói Nagy-tó, Sárkány-tó and Vadása-tó showed significant relative contribution to β-diversity. Cl- and HCO3 - content were determining factors for LCBD, whereas local species richness was related to HCO3 - and water temperature. Moreover, we found a decline in LCBD with the increase of species richness. The study was supported by the National Scientific Research Foundation (OTKA K81599), the Széchenyi 2020 under the EFOP-3.6.1-16-2016-00015 and the ÚNKP-17-3-IV-PE-5 New National Excellence Program of the Ministry of Human Capacities

Application of an induced fluorometry-based method in algal growth inhibition tests

Aquatic ecosystems are strongly exposed to various micropollutants from agricultural origin. The harmful effect can be expressed directly on aquatic organisms and indirectly through the food chain. The use of ecotoxicity assays mainly in aquatic environments, and corresponding water quality assessment are undoubtedly important. Project Aquafluosense was designed to develop instrument prototypes of a fluorescence-based setup for in situ measurement of algal biomass and for application of flurescence in ecotoxicity assays. Fluorescence-based determination of algal density was validated by conventional methods and signals obtained by the fluorometer correlated well with the conventional methods for algal density determination. The applicability of the fluorometer developed was demonstrated in ecotoxicity assays using the herbicide active ingredient isoxaflutole in neat and formulated forms

Anticipated Impacts of Climate Change on the Structure and Function of Phytobenthos in Freshwater Lakes

Climate change threatens surface waters worldwide, especially shallow lakes where one of the expected consequences is a sharp increase in their water temperatures. Phytobenthos is an essential, but still less studied component of aquatic ecosystems, and it would be important to learn more about how global warming will affect this community in shallow lakes. In this research, the effects of different climate change scenarios (SSP2-4.5 and SSP5-8.5, as intermediate and high emission scenarios) on the structure and function of the entire phytobenthos community using species- and trait-based approaches were experimentally investigated in an outdoor mesocosm system. Our results show that the forecasted 3 ◦C increase in temperature will already exert significant impacts on the benthic algal community by (1) altering its species and (2) trait composition (smaller cell size, lower abundance of colonial and higher of filamentous forms); (3) decreasing Shannon diversity; and (4) enhancing the variability of the community. Higher increase in the temperature (+5 ◦C) will imply more drastic alterations in freshwater phytobenthos by (1) inducing very high variability in species composition and compositional changes even in phylum level (towards higher abundance of Cyanobacteria and Chlorophyta at the expense of Bacillariophyta); (2) continuing shift in trait composition (benefits for smaller cell volume, filamentous life-forms, non-motile and weakly attached taxa); (3) further reducing the functional diversity; (4) increasing biofilm thickness (1.4 μm/◦C) and (5) decreasing maximum quantum yield of photosystem II. In conclusion, already the intermediate emission scenario will predictably induce high risk in biodiversity issues, the high emission scenario will imply drastic impacts on the benthic algae endangering even the function of the ecosystem