Toxic red algae, which cause bloody rains and red tides, are rapidly spreading across the seas and oceans due to their absolute omnivorousness, according to Russian scientists who published an article in the journal Estuarine, Coastal and Shelf Science.
“It turned out that dinoflagellates Prorocentrum minimum can feed on both inorganic compounds - nitrogen dissolved in water - and organic substances, including urea, a popular fertilizer. If there are not enough inorganic compounds in the water, then this type switches to urea. Therefore, there are no conditions in which he would be uncomfortable,”says Sergei Scarlato from the Institute of Cytology of the Russian Academy of Sciences in St. Petersburg, quoted by the press service of the Russian Science Foundation.
In recent years, residents of Spain, the Caribbean and some other regions have experienced unusual phenomena - "blood rains" and red tides, which many religious people considered a sign of the imminent end of the world. Of course, there is nothing supernatural about them - these anomalies have arisen as a result of rapid reproduction and flowering of brown algae.
Red tides are extremely dangerous for other types of microbes, as well as fish and birds, as the microorganisms that form them secrete brevetoxin (nerve poison) and other dangerous substances. As scientists recently found out, this happens when plankton lacks certain trace elements - thus it develops a kind of "chemical weapon" to destroy competitors and massacre potential sources of necessary substances.
Scarlato and his colleagues discovered the secret of the "life success" of such microorganisms, observing the growth of Prorocentrum minimum algae, which recently colonized the Baltic Sea and completely displaced the plankton species that previously lived in its waters. Large colonies of these microbes often form spots off the coast of Russia and the Baltic States, threatening fish populations and human health.
As it turned out, algae have a whole arsenal of tools and techniques that help them survive even in the most adverse conditions. For example, when the water salinity is abnormally low, they dramatically increase the metabolic rate in order to compensate for the disturbances in the functioning of DNA and proteins.
When scientists deprived Prorocentrum minimum of their main food - inorganic nitrogen compounds that enter the water of the seas along with mineral fertilizers - the algae did not die, but simply switched to urea and other organic nitrogen sources, which are traces of animal life or the decomposition products of their tissues and cells. … Such substances, as biologists note, are usually toxic to plankton, but Prorocentrum minimum cells have learned to replace nitrates and other “non-living” nitrogen sources with them.
The combination of these factors, according to Scarlato, explains why the epidemic of "blood tides" so quickly swept the Baltic. The ability to adapt to low or high salt water concentrations and omnivorousness have helped the Prorocentrum minimum colonize the relatively unstable coastal ecosystems of the Baltic Sea, where salinity levels and nutrient availability often change dramatically.
Promotional video:
“With new data accumulating in the future, we want to create a model that can predict when and under what conditions these potentially toxic organisms will proliferate. Then we will be able to anticipate this process and find a way to regulate it,”concluded Scarlato.
