The canaries will have to “learn to live” with the microalgae, whose massive arrival on the coasts of the archipelago will be increasingly common due to the global warming of the Atlantic Ocean in the Macaronesia region.
This is one of the conclusions of a scientific team made up of researchers from the Institute of Sustainable Aquaculture and Marine Ecosystems (Ecoaqua) of the University of Las Palmas de Gran Canaria, of the Institute of Mathematical Sciences (Icmat), the CSIC, and the technology company Digital Earth Solutions (DES).
This team has developed a system for predicting the arrival of these microalgae patches to the coasts Canary Islands up to 72 hours in advance.
Between June and September he has been documenting the appearance of massive outcrops of cTrichodesmium ianobacteria in the coastal waters of Gran Canariaas well as in Tenerife, The Palm, La Gomera and The ironwhose presence, he warns, could visibly last until October.
In a statement, the researchers explain that this type of cyanobacteria is very common in subtropical and tropical areas, in waters with temperature ranges above 23 degrees Celsius.
Since the massive upwelling episode of microalgae reported in 2017, their presence in Canary Islands waters has begun to be more frequent due to the global warming of the Atlantic Ocean in Macaronesia, and the consequent increase in temperature in this area.
Scientists expect their arrival to occur periodically, although it is not all bad news.
Because although bathing in its presence is not advisable, its appearance is positive for the environment by fixing carbon dioxide, just as the rest of the plant communities do, oxygenating the waters in which they are found and feeding the rest of the plant. food chain.
Professor Antonio González Ramos, from Ecoaqua, explains that colonies in the form of “capsules” (trichomes) appear on the surface when there is ‘quicha calm’ in the sea, and “disappear” with the wind, sinking and dispersing when returning to their shape. unicellular.
“The population will have to learn to live with them,” says González Ramos, so when the ‘blooms’ (outcrops) reach the coast degraded, they form whitish ‘creams’ (caspases) that release ammonia, which in addition to generating bad odors. They can cause hives in case of direct contact.
Therefore, it would only be necessary to prohibit bathing on the beaches, or sectors thereof, where they appear, as stated. would do in the case of the appearance of jellyfish outcrops in coastal waters, the expert argues.
To prepare the study, very high resolution scenes from the European constellation of Sentinel 2A and 2B satellites, from the European Copernicus environmental monitoring program, have been used.
In each image analyzed, different RGB combinations (red, green and blue) were made among the 13 available bands, in order to identify the presence of the cyanobacteria in the different environmental scenarios.
Once the ‘blooms’ are identified in the satellite images, they are isolated from the rest of the scene and are projected spatio-temporally using hourly current fields obtained from the European Copernicus Marine System.
To do this, an advanced mathematical model developed by Icmat/CSIC, the company DES and the Ecoaqua institute of the University of The Gran Canarian palmswhich “very precisely” predicts the time and place of arrival of cyanobacteria accumulations on the coasts in an hourly range of up to 72 hours.
The cyanobacterial outcrops form large “lamparones”, or “filamentary lines” tens of kilometers long, depending on the coastal dynamics at each geographical point of the islands.
In both cases, the system developed by this scientific team is capable of detecting and predicting its time evolution, including possible splits and subdivisions of the original shapes obtained from satellite images.
So far, the massive arrival of cyanobacteria has affected a large part of the beaches located in the southeast and southwest of Gran Canaria, although there have been reports of arrival in The pits coinciding with periods of calm throughout the northern sector of the island.
In the western islands it affected the southeast, south and southwest of Tenerife, the east and south of El Hierro, the west of La Palma and all of the south of La Gomera.
Rows of all sizes, many measuring tens of kilometers, were found during August in the calm waters of the western islands.
Specifically, one of the reports of Trichodesmium, located in the south of La Gomera and in the east of El Hierro, covered an area of 100 square kilometers.
This methodology for predicting massive episodes of microalgae has been previously tested and published in international journals by this same team of researchers within the framework of the European project H2020 IMPRESSIVE, which had as its objective the reporting and evolution of oil spills in port waters.
In fact, the team intervened in cases such as the sinking of the Russian fishing boat Oleg Naydenov in 2015 in waters south of Gran Canaria, the spill of the Volcán de Tamasite ferry in the Port of Light in 2017 or the multiple oil spills that devastated the coasts of the eastern Mediterranean in 2021.
Trichodesmium sp is a prokaryotic phytoplankton species that “invented” normal photosynthesis 3.5 billion years ago, which has been inherited by its eukaryotic descendants: microalgae, macroalgae and higher marine plants.
Like these, Trichodesmium consume Carbon Dioxide (CO2), produce Oxygen (O2) and feed the rest of the marine food chain.
He richodesmium However, it has the unique characteristic of being “diazotrophic”: it is capable of fixing Nitrogen (N2) when there is no Nitrate (NO3), a dissolved gas available in water, which is the form of Nitrogen used by the rest of unicellular plants or marine and terrestrial multicellular organisms.
Therefore, when the sea is very warm, the NO3 from deep waters does not appear on the surface, making the rest of the microalgae, macroalgae or higher marine plants unable to proliferate.
When the waters cool and mix with the deeper ones, NO3 reappears in the surface waters, and with it the rest of the marine plants, micro and macroalgae, responsible for the sequestration of CO2 in the ocean and the subsequent production, reproduce again. of O2. EFE