Phytoplankton diversity of a natural karst lake combining morphological and molecular approaches
Phytoplankton are considered to be one of the most sensitive indicators of the lake ecological status. Nowadays, it is essential to recognize the prospects of the molecular approach (eDNA metabarcoding) in the phytoplankton community assessments and combine them with the exist-ing traditional microscopy-based morphological approach before its standardization. In this study, we aimed to characterize the phytoplankton community of a natural karstic lake by combining and comparing the morphological and molecular approach to check the applicability of eDNA metabarcoding as a biomonitoring tool. The comparability of both approaches in describing phytoplankton community is evident in the designation of centric diatoms, dinoflagellates and cryptophytes as descriptive taxa. Also, both approaches proved reliable in detecting functional groups (Lo, C, X2, X3) with similar ecological demands. Moreover, the results have shown that euphotic zone samples can be reliably exchanged by composite samples to provide an accurate characterization of phytoplankton community in the euphotic zone. We confirmed that eDNA metabarcoding is an applicable tool for biodiversity monitoring of a natural karst lake and should be used as a feasible supplement to traditional microscopy in the phytoplankton community assessments, with regards to drawbacks of each method.