Biomonitoring of phytoplankton communities changes following heavy metals fluctuations in lake Balkhash ecosystem

In the world threatened by multiple anthropogenic impacts, innovative approaches
to lake ecosystems monitoring and assessment are required for proper water
management. We have designed an innovative approach combining the
characterization and counting of microalgae groups based on imaging flow
cytometry (IFC; FlowCam) coupled with detailed chemical analysis. The aims of
our multi-parametric approach are to monitor the lake waters for phytoplankton
diversity, composition, abundances, and correlate it with physico-chemical
parameters and heavy metals concentrations. We performed biomonitoring of 14
sampling stations at Lake Balkhash, one of larges lakes in Asia located in
southeastern Kazakhstan. The shallowing of Balkhash lake and environmental
impacts of emissions due to mining, metallurgical processes, and inflow of
polluted water from Ili river (comes from China) creates serious concerns about
the functioning of the lake ecosystem. In details, IFC biomonitoring of
phytoplankton communities was performed in parallel with chemical analysis of
surface water for heavy metals (Fe, Cu, Zn, Mn, Cd) and ions (potassium,
ammonium, nitrates/nitrites) by atomic absorption spectrometry with Analyst 400
(Perkin-Elmer) and ion chromatography with Methron Compact IC FLEX 930
(Methron). Our characterization of morphological traits of microalgal cells by IFC
offered a high level of statistical reproducibility and allowed to characterize the
response of phytoplankton communities to applied stressors such as fluctuations in heavy metals concentrations and ions. RDA and bivariate correlation analysis
demonstrated the positive correlation of nanoplankton abundance with increased
levels of Fe (r=0.83) and large pennate diatoms (including Ulnaria sp and
Entomoneis sp) with manganese and copper. Identification of microalgal groups
that may serve as bioindicators of changes in phytoplankton communities
structure and diversity towards heavy metals and other pollutants is expected to
lead to better monitoring and environmental management of lake aquatic
biosystems. The poster presents methods and results with a major focus on multiparametric innovative approach and a correlative analysis of heavy metals levels
and phytoplankton taxonomic group abundances and diversity