The use of charophyte algae in ecological status assessment of lakes – developing new methods based on eDNA

Charophyte algae have long been used for the ecological status assessment of lakes. Traditional fieldwork and species determination are, however, time-consuming and expensive. In the BIOLAWEB project, we aim to use environmental DNA (eDNA) for metabarcoding of Chara sp. in the water samples from selected lakes, and use this information to develop new or improve existing indices for the ecological status assessment of lakes. Ecological status assessment of lakes is important to safeguard biodiversity, and to ensure that lakes are in good enough status to safely be used for, among others, drinking water production, and recreation. Charophytes are benthic algae which are sensitive to changes in water quality and therefore are important indicators for ecological status. The use of eDNA is an approach that can be used to quickly detect the presence of different species in a lake, including species that are easily overlooked with more traditional, time-consuming methods. The use of eDNA for ecological status assessment is, therefore, a new and promising field of study. Here we present preliminary results of charophyte investigations in four lakes in Serbia, two freshwater and two saline lakes, in three seasons. Besides traditional sampling of charophytes, water samples were filtered for eDNA, aiming to generate new knowledge on the use of DNA metabarcoding for the detection of charophyte algae and for improving indices for ecological status assessment.