Cyanobacterial blooms: toxicity, diversity, modelling and management

Cyanobacterial blooms, mass developments of cyanobacteria floating at the surface of waterbodies, have become a recurrent and increasingly important phenomenon in freshwaters worldwide over the last decades. The formation of such blooms in surface waters is highly linked to water eutrophication (Chorus, 2001). These nuisance blooms represent major potential hazards for human and animal health, and interfere in various negative ways with the sustainable use of surface waters for e.g. drinking water treatment, recreation, irrigation, fisheries. Between 25 and 70% of the blooms are toxic (Sivonen, 1996). The cyanotoxins are mainly released in the water column during collapse of the blooms. The ingestion or contact with water containing cyanobacterial cells or toxins can cause health damage (Bell & Codd 1996; Carmichael et al. 2001; de Figueiredo et al., 2004; Dittmann & Wiegand, 2006).

In view of the lack of knowledge about the situation in Belgium, three of the present partners initiated, 3 years ago, the BELSPO project B-BLOOMS. Thanks to this work, it has been shown that the surface waters in Belgium are also plagued by cyanobacterial blooms, particularly in summer and autumn. Eighty % of the blooms contained taxa with the genetic potential to synthetise microcystins, and the presence of this toxin in the algal biomass was shown by HPLC analysis for 40% of the analysed bloom samples. The need of monitoring blooms in Belgium was confirmed by a recent paper of Willame et al. (2005) where 53% of the analysed bloom samples contained microcystins.

This project aims to deepen the knowledge of the cyanobacterial blooms in Belgium, improve the modelling for prediction and early-warning, develop operational monitoring structures and tools, and propose strategies to reduce the impact.

Objectives

From a scientific point of view, the research program will focus on:

* Measurement of the major toxins present in the blooms and water samples by analytical methods, ELISA and Mass Spectrometry methods
* Collection of physical, chemical, biological and meteorological data on a few reference waterbodies plagued by toxic cyanobacterial blooms
* Identification and study of the toxigenic cyanobacteria present in the Belgian samples based on molecular tools on samples and strains, including genetic diversity, and factors regulating toxicity.
* Development and test of management scenarios for control or mitigation of cyanobacterial blooms in one reservoir using integrated watershed models
* Development of a statistical predictive model for a series of urban ponds