Spatial and thematic distribution of research on cyanotoxins.

Cyanobacteria in surface water are well known for their ability to form toxic blooms responsible for animal mortality and human poisoning. Accompanying major progress in science and technology, the state of knowledge of cyanotoxins has dramatically increased over the last two decades. The bibliometric approach applied in this study shows the evolution of research and identifies major gaps to be filled by future work. Although the publication rate has gradually increased from one hundred to three hundred articles per year since the 1990s, half of the literature available focuses on microcystins and another quarter on saxitoxins. Other cyanotoxins such as beta-N-methylamino-l-alanine or cylindrospermopsin remain vastly disregarded. Moreover, most of the publications deal with toxicity and ecology while other research areas, such as environmental and public health, require additional investigation. The analysis of the literature highlights the main journals for the communication of knowledge on cyanotoxins but also reveals that 90% of the research is originated from only ten countries. These countries are also those with the highest H-index and average number of citation per article. Nonetheless, the ranking of these countries is significantly altered when the amount of publications is normalized based on the population, the number of universities, the national gross domestic product or the government revenue. However, the lower amount of publications from Eastern Europe, Africa and South America could also reflect the lack of monitoring campaigns in these regions. This lack could potentially lead to the underestimation of the prevalence of toxic cyanobacterial blooms and the diversity of toxins worldwide.