The profound effect of harmful cyanobacterial blooms: From food-web and management perspectives

Abstract

Sustainable and effective water management plans must have a reliable risk assessment strategies for harmful cyanobacterial blooms (HABs) that would enable timely decisions to be made, thus avoiding the trespassing of ecological thresholds, leading to the collapse of ecosystem structure and function. Such strategies are usually based on cyanobacterial biomass and/or on the monitoring of known toxins, which may, however, in many cases, under- or over-represent the actual toxicity of the HAB. Therefore, in this study, by the application of growth-inhibition assays using different bacteria, algae, zooplankton and fish species, we assessed the toxicological potential of two cyanobacterial blooms that differed in total cyanobacterial biomass, species composition and cyanopeptide profiles. We demonstrated that neither cyanobacterial community composition nor its relative abundance, nor indeed concentrations of known toxins reflected the potential risk of HAB based on growth-inhibition assays. We discuss our findings in the context of food-web dynamics and ecosystem management, and suggest that toxicological tests should constitute a key element in the routine monitoring of water bodies so as to prevent under-/over-estimation of potential HAB risk for both ecosystem and public health.

Genomic analysis of red-tide water bloomed with Heterosigma akashiwo in Geoje

“…This result showed that the ratios of phytoplankton to heterotrophic bacteria in the bloom (0.0410422) and edge sites (0.0483856), which was approximately twofold higher than in the control site (0.0910008). This result supports the previous result HAB redirects carbon and energy flow within the pelagic food-web toward heterotrophic bacteria-dominated processes, primarily through the inhibition of algal growth and enhancement of bacterial proliferation ( Šulčius et al, 2017 ). Since microbial ecosystems in aquatic environments are the result of complicated interactions between photosynthetic phytoplankton species and heterotrophic microorganisms ( Carrillo, Medina-Sánchez & Villar-Argaiz, 2002 ; Cole, 1982 ; Rooney-Varga et al, 2005 ), it is often necessary to analyze the phytoplankton community separate from the other bacterial species.…”

Dynamics of Bacterial and Fungal Communities during the Outbreak and Decline of an Algal Bloom in a Drinking Water Reservoir

“…Algal blooms have become a worldwide and challenging water pollution problem in freshwater ecosystems due to harmful algae that cause a gradual degeneration of the water’s self-purification function and decrease the source water quality [ 1 , 2 ]. In the past several decades, a growing number of studies concerning the environmental factors of algal bloom outbreaks and decline have been explored [ 2 ].…”

Phytoplankton of the Curonian Lagoon as a New Interesting Source for Bioactive Natural Products. Special Impact on Cyanobacterial Metabolites

“…In terms of cyanobacterial toxins, the presence of various microcystin (MC) analogues, anatoxin-a (ANTX-a) and nodularin (NOD) has been confirmed [7,9,12,13]. Reports on the detection of cyanopeptides in the Curonian Lagoon was also published [10,13].…”

“…Previous research in the Curonian Lagoon has only focused on the ecotoxicological assessment of cyanobacterial scum and cyanobacterial toxins from the perspective of the ecosystem and public health [7,[9][10][11][12][13]. To our knowledge, no published data on the biological activity of metabolites produced by cyanobacteria and eukaryotic microalgae occurring in this lagoon exist.…”