INNOVATIVE DETECTION OF TOXIC ALGALE PROLIFERATIONS: A NECESSITY IN THE FACE OF GLOBAL WARMING (DIANAS; National R&D&I Plan, 2018-2021)

Harmful and toxic algal blooms (HABs) are a growing problem for coastal economies around the world. These phenomena are caused by the massive proliferation of microalgae that produce bioaccumulative toxins in bivalve mollusks or fish, through whose consumption they seriously affect human health. During the last decades, the level of aggravation of this problem has been a matter of debate, since the greater scientific awareness of the problem together with the improvement in the detection capacity generated doubts about whether its increase was true or only apparent.

However, in recent years, various investigations have revealed that there is a clear anthropogenic effect behind the increase in the occurrence of certain HAB events, in relation to their intensification (duration and toxicity) and their growing biogeographic expansion, dependent both on climate change and other factors derived from human intervention on the environment, such as eutrophication of waters, artificial modification of the coastline or the transport of non-native species using ballast waters. Consequently, there is no doubt that it is necessary to anticipate a foreseeable worsening of the problem and deepen our knowledge of the causative organisms in order to develop better and more effective predictive tools and, if possible, their mitigation.

Specifically, global warming has been directly related to the increase in proliferation and latitudinal expansion of two groups of microalgae that cause two serious poisonings in humans: Paralyzing toxin poisoning (PSP), caused by consumption of bivalve mollusks, and ciguatera, which is currently the most serious poisoning caused by fish consumption worldwide. The main and general objectives of this project are two: First, the development of methodologies leading to the improvement in the detection of organisms and/or effects of these toxic episodes in order to effectively prevent any harmful effect on human health, and second, the study of key biological and environmental factors to explain the variability in virulence (toxicity) of these episodes.

Regarding ciguatera, to improve the detection of the causative organisms it is first necessary to: 1.- Understand its still unknown ecological niche, evaluating proliferation rates and mechanisms “in situ”, with the consequent development of effective sampling methods in accordance with it; 2.- the development of molecular methods that allow the counting of toxic species. In reference to paralyzing toxin poisoning, we propose that an effective prediction involves understanding how the increase in temperature influences the increase in the proliferation rate and toxicity of the bloom. To do this, 1.- The division mechanisms will be studied, mainly those enhanced by temperature (sexuality), and 2.- Their relationship with the expression of the genes involved in the production of paralyzing toxin (saxitoxin, STX).