Research

1. Investigation of the ecological role of invasive mussel species in Lake Balaton
Our research focuses on the population dynamics and ecological role of the invasive dreissenid species. We examine the colonization, food preference and metabolism of the animals using experimental methods on animals collect from natural habitats, on implanted ones and on those kept in aquaria. We examine also the ecological role of dreissenids in the food we structure of Lake Balaton.

2. Human impacts on freshwater biodiversity
We examine the effects of human impacts on freshwater biodiversity. We focus on how the different facets (taxonomic, phylogenetic and functional) and components (alpha and beta) of diversity, as well as the taxonomic- and trait-based community respond to anthropogenic disturbances such as urbanization, pollution, habitat degradation, spread of invasive species or climate change.

3. Development and use of methods of numerical ecology
We deal also with the methodology of community ecology. We are interested in approaches quantifying community-level phenomena such as beta diversity or nestedness, as well as in methodology enumerating functional diversity.

Activity of the research group:

The research group was established in 2021 from the previous Adaptive Neuroethological Research Group supported by National Brain Program (NAP2.0) and Chemical Ecology Research Group.

Mission of the research group:

Complex (eco)physiological and toxicological investigations of the effects of both natural and anthropogenic pollutants detected in Lake Balaton on aquatic invertebrate and lower vertebrate species in a top-down approach with model multidisciplinary applications. An important part of our mission is to communicate the practical implications of our scientific findings to the decision makers, water authorities, nature conservationists, and also to the public.

Tasks of the research group:

1) Monitoring of the presence of natural and anthropogenic pollutants (e.g., cianotoxins, drug residues, UV-filters, pesticides, rodenticides, microplastics) in Lake Balaton. Chemical characterization of aquatic environment (water body, sediment, phyto- and zooplankton, phyto-and zoobenthos, macrophyton, macro invertebrates, fish) with special attention to the spatio-temporal variations of pollution sources as well as identification, quantification and adsorption of different pollutants. 
2) Investigation of the long-term combined effects of climate change and anthropogenic stressors in aquatic ecosystems. We examine the changes of the abiotic environmental factors (e.g., extreme temperature, salinity, pH, and redox processes) caused by climate change on the physiological functions and adaptive ability of major animal taxa (zooplankton, arthropods, mollusks, fish). Characterization of molecular underpinnings of adaptation. 
3) In the framework of field studies, we analyze the effects of anthropogenic pollution of wetlands on the general condition, reproductive capacity, and cellular and molecular level changes of aquatic invertebrate and fish indicator organisms. At the population level, we obtain information by comparing the condition indices of individuals collected from more polluted (e.g., harbors, beaches, around treated sewage inlets) and more protected (e.g., nature conservation bays) areas.
4) In controlled laboratory experiments, we investigate the individual and mixture effects of pollutants on (neuro)physiological functions (feeding, locomotion, breathing, development, reproduction, learning) of representative aquatic model organisms from laboratory-bred animals at the individual, tissue, cell and molecular levels (top-down approach), using multidisciplinary (physiological, histological, biochemical, molecular, genetic) methods. At the cellular level, we map the mechanism of action of toxicity on oxidative stress and biotransformation systems, as well as investigate neurophysiological effects on identified cells and simple neural networks during exposure to environmentally relevant complex pollutant mixtures. At the molecular level (mRNA), we investigate the expression changes of known stress markers (e.g. GnRH/CRZ, CREB, DJ- 1, p38alpha, JNK1, etc.).
5) A complex environmental condition assessment of Lake Balaton and the development of a reliable exposure- and biomarker-based wetland monitoring strategy based on environmental analytical surveys, environmental risk assessment and the general toxicity of pollutants. In this way, we can determine the general condition of the organisms inhabiting the given wetland in a cost-effective and environmentally friendly way, and at the same time we can weight the importance of the complex stress effects on the aquatic community from natural and anthropogenic sources on the environment. 

We examine the biodiversity and organization of freshwater fish assemblages.

Our primary model system are the Danube and Lake Balaton and its catchment, which is affected by a variety of human impacts. The primary focus is to explore the environmental drivers of population dynamics and assemblage organization, and, from an applied perspective, to provide suggestions for environmental managers and conservationists to mitigate human impacts. Specifically, we examine the habitat use, ontogenetic diet patterns, trophic relationships, growth, and survival of fish in Lake Balaton. The main task of the monitoring of the waterbasin’s streams is to follow the distribution of non-native invasive species and to explore their impact on the native fauna. We also examine the organization of fish assemblages in the River Danube and its floodplain system.

Increasing emphasis is given to the study of the diversity and distribution of fish in a regional (country-wide) scale to develop monitoring systems for evaluating environmental health, to base conservation planning actions and to explore the effects of human impacts on freshwater biodiversity in the Pannon Ecoregion.

The task of the Research Group is to investigate and monitor the biomass and composition, spatial heterogeneity, and seasonal dynamics of the zooplankton community inhabiting Lake Balaton. Zooplankton refers to the animal component of the planktonic community in aquatic ecosystems, which mediates nutrients and energy between lower (algae, bacteria) and higher trophic levels (e.g., fish) of the food chain. It serves as the basic food source for all juvenile fish in Lake Balaton, but several fish species also consume it in their adult stages. Through filter feeding, zooplankton can control the quantity of floating algae, thus exerting an important influence on water quality.

The Research Group also operates the mesocosm system of BLKI, consisting of 12 outdoor tanks (mesocosm: an experimental system that examines the natural environment under controlled conditions). In these five cubic meter tanks, water temperature, nutrient levels, water flow rate, incident light intensity, and other factors depending on the objective of the experiments can be regulated. Sensors installed in the tanks continuously measure the most important physical parameters in the water (e.g., incoming light, water temperature, pH, dissolved oxygen, etc.). The mesocosm tanks can be filled either with unfiltered water from Lake Balaton (pumped in directly from the lake) or with lake water filtered in three stages (gravel-, sand-, and UV-filtration). With this system, researchers can investigate/model ecological phenomena under controlled conditions, such as the impact of global climate change on aquatic communities or the interactions of environmental factors promoting algal blooms.