The water in some estuaries, ports, beaches and other coastal areas occasionally turns a reddish, greenish or brownish colour. These conditions are caused by certain species of single celled, microscopic algae, mainly dinoflagellates, which produce a series of compound chemicals which can be toxic for both the fauna and humans via the food chain. Localized increases in the number of these organisms are called Harmful Algal Blooms, HABs.

The impact of these harmful blooms on the economies of countries which use the seas is growing. These proliferations can have varied effects, ranging from a simple deterioration of the aesthetic quality of the water to huge mortality rates in marine organisms (including fish in fish farms) or even food poisoning in humans due to the consumption of shellfish. The toxins PSP (Paralytic Shellfish Poison, a toxin with neurological effects) or DSP (Diarrheic Shellfish Poison) can produce toxicity even when the biotoxic concentrations are very low in the organisms.

 Monitoring programmes
Toxic algae are known to exist for long in the Iberian Peninsula, especially in Galician rías, where their economic impact on mussel harvesting is very important.  However, the monitoring programmes that cover the majority of the Iberian coasts has revealed not only how widespread HABs are, but also the variety of toxic and harmful species involved in these events. The physiology, ecology and life-cycles of the bloom forming organisms and the factors which influence their appearances can be very different.

Many of these monitoring programmes have been made possible by the implementation of different European Directives, the latest of these Water Framework Directive and the Marine Strategy Framework Directive pay special attention to the environmental and health aspects of the problem and force the European Governments to consider harmful algae in their monitoring programmes in coastal waters.

 What is REDIBAL?
REDIBAL has been conceived as a professional thematic network dealing with harmful algae, and was born out of the spirit of promoting interaction among scientists, technicians, managers and other groups of interest in the Iberian Peninsula. The dispersion of coastal monitoring efforts and the continuous scientific advances made in the methods of detection and mitigation of harmful algae make it advisable to establish a system for the exchange of knowledge between scientists and environmental management agencies so that the effort dedicated to this matter can function more efficiently.

Furthermore, the intention of REDIBAL is to open an information exchange channel between science and society regarding harmful algae by promoting leadership in the areas of education and transmission of information related to this topic.