Toxic cyanobacterial blooms are a growing threat to freshwater bodies worldwide. In order for a toxic bloom to occur, a population of cells with the genetic capacity to produce toxins must be present together with the appropriate environmental conditions. In this study, we investigated the distribution patterns and phylogeny of potentially-toxic Microcystis (indicated by the presence and/or phylogeny of the mcyD and mcyA genes). Samples were collected from the water column of almost 60 water bodies across widely differing gradients of environmental conditions and land use in Israel. Potentially, toxic populations were common but not ubiquitous, detected in ~65% of the studied sites. Local environmental factors, including phosphorus and ammonia concentrations and pH, as well as regional conditions such as the distance from built areas and nature reserves, were correlated with the distribution of the mcyD gene. A specific phylogenetic clade of Microcystis, defined using the sequence of the mcyA gene, was preferentially associated with aquaculture facilities but not irrigation reservoirs. Our results reveal important environmental, geospatial, and land use parameters affecting the geographic distribution of toxinogenic Microcystis, suggesting non-random dispersal of these globally abundant toxic cyanobacteria.
Bibliographical noteFunding Information:
We thank Hans-Peter Grossart and Assaf Sukenik for providing toxinogenic and non-toxinogenic strains and for helpful discussions. We also thank Tamar Rachamim, Eliezra Glasser, Elad Rachmilovich, Omri Shabbat, and Sophia Barinova for help with sampling, and many water managers for sampling access and helpful insights. Sampling was performed in accordance with permit number 40258 from the Israel National Parks Authority. This study was supported in part by grant 3-10342 from the Israel Ministry of Science and Technology and by Marie Curie Career Integration Grant MICROBES-2-MODEL.
© 2016 Marmen, Aharonovich, Grossowicz, Blank, Yacobi and Sher.
ASJC Scopus subject areas
- Microbiology (medical)