POTENTIALLY TOXIC ALGAE DETECTION AND MONITORING IN KAZAKHSTANI LAKES AND RIVERS

Abstract

An increasing scale of emerging cases of Harmful Algal Blooms (HABs) around the world requires a time-effective and facile methodology of toxic algae detection and quantification. The traditional methods such as light microscopy, ELISA (enzyme-linked immunosorbent assay), HPLC (high-performance liquid chromatography), and LC-MS (liquid chromatography-mass spectrometry) take cost and effort to produce an outcome while novel remote sensing technique can be partly sensitive at the early stages of HABs development. The proposed methodology of rapid detection of blooms using imaging flow cytometer FlowCAM integrated with PCR-based methods was adapted to the eleven water bodies in different regions of Kazakhstan. The analysis of algal samples from the Ural River's delta up to 100 km inland was carried out in August–December 2019 using imaging flow cytometry (IFC), molecular biological, and microscopic techniques. As dominant phytoplankton species, we identified the filamentous cyanobacteria Cuspidothrix issatschenkoi, Dolichospermum cf. flos-aquae, Pseudanabaena limnetica, and we found minor quantities of Cylindrospermopsis raciborskii. Real-time PCR analysis and Sanger sequencing indicated the presence in the field samples containing Microcystis spp. of genes associated with the production of microcystin (mcyE). Moreover, we identified potentially toxic cyanobacteria by IFC in seven other Kazakhstani water bodies. The present study describes the advantages and suggests the particular effectiveness of imaging flow cytometer FlowCAM in the fast detection of potentially toxic algae in rivers and lakes. Developed combined IFC and PCR-based approach can be useful in early detection and monitoring of toxic algae in Kazakhstani rivers and lakes.