Researchers of the ELKH Balaton Limnological Research Institute (BLKI), in cooperation with the Sustainability Solutions Research Lab of the University of Pannonia, the Institute of Genetics of the ELKH Biological Research Centre, Szeged (BRC), and the Copernicus University of Turku (Poland), investigated the turnover of transition metals and semi-metals in Lake Balaton. They found that the invasive Dreissena mussel species – the quagga mussel and the zebra mussel – which occur in large numbers in the lake, play a dominant role in the movement and storage of both natural geochemical background and anthropogenic elements, according to their seasonal activity. The results of the study were published in the journal Biogeochemistry.

The functioning of a pond as an ecosystem is characterized by the exchange of material between living and non-living phases such as water, sediment and organisms. Within the framework of the project, the researchers analyzed 17 elements in the water, surface sediments, soft tissue and shells of mussels at different times of the year in the Keszthely, Szigliget and Siófok basins of the lake, which have different trophic levels. Research has explored the relationship between elements with similar behavior and element movements between phases.

The results show that changes in the metal content of mussels may also be related to events such as late summer sediment or water surface oxygen deficits and algal blooms in the western basins of Lake Balaton. Increased urbanization around the Siófok basin and the use of sprays containing copper to control fungal infections in vineyards around the lake may also have an impact on this process.

In addition to element content measurements, the researchers also examined – for the first time in the case of mussels in Balaton – the gene expression of proteins indicative of the metal load of the mussels. In addition to their key role in the food chain of the shoreline, invasive mussels have been found to be important in the lake’s elemental cycling and are therefore considered indicators of environmental events and their impact on organisms. The researchers emphasized that, as in previous decades, human-induced metal pollution continues to pose no environmental risk to the lake as a whole and has even decreased slightly.

Research aimed at protecting Lake Balaton and preserving its environmental status is a priority of BLKI. The researchers also plan to launch a ‘vitality-monitoring program’ to monitor the condition and the genes responsible for the defense and repair mechanisms of Dreissena mussels in Lake Balaton. This is modelled on the “Mussel Watch” program, which has already been introduced in several locations.

The research was funded by projects MAHOP-2.1.1-2016-2017-00005, GINOP-2.2.1-15-2017-00070 and NKFIH-471-3/2021.