The CSIC uses satellite images to monitor red tides in the Galician estuaries
Researchers insist on the need to incorporate these remote sensing tools into traditional control programs
The application of this technology would allow greater detail for the monitoring of potentially toxic phytoplankton blooms.
Sevilla/ Cádiz/ Vigo, Thursday, January 26, 2023. Researchers from the Higher Council for Scientific Research (CSIC) have developed a methodology that allows, using satellite images, to monitor two microscopic organisms that cause red tides in the Galician estuaries. In the study, published in Science of the Total Environment , have observed the dinoflagellates (unicellular organisms that are part of the microplankton) Noctiluca scintillans and Alexandrium , whose presence may mean the appearance of toxins in the area.
"The importance of this research lies in the fine-tuning of a new methodology to detect algae blooms in detail in almost real time, using the Sentinel-2 satellites, including harmful species that , in Galicia, due to the accumulation of their Toxins in shellfish cause damage to sectors such as aquaculture by posing a risk to human and animal health”, explains Isabel Caballero de Frutos , a CSIC researcher at ICMAN.
The formation of red tides is a natural phenomenon, which can sometimes alert harmful algal blooms ( HABs ), as is the case with some Alexandrium species . Biotoxins pose a frequent problem in Galicia during the summer season, with significant economic losses in the aquaculture sector related to the exploitation of shellfish in natural beds and crops. Marine resources such as mussels seasonally accumulate the toxins produced by some species of phytoplankton, and if they reach the maximum permitted levels, their collection and sale to consumers is prohibited.
The authors of the study insist on the need to incorporate these free and public remote sensing tools into traditional monitoring programs. Although as a general rule red tides are not usually toxic in Galicia, there are exceptions such as Alexandrium in the summer of 2018 in the Rías Baixas. "The development of these tools with the satellites of the European Copernicus program of the European Commission will help us to be better prepared during the periods of greatest risk of the appearance of HABs , advancing early warning and monitoring of toxic episodes with the aim of achieve better management of marine resources”, explains Amália Maria Sacilotto , CSIC researcher at ICMAN and main author of the work.
Years of work
The study, in which researchers from the Institute of Marine Sciences of Andalusia (ICMAN-CSIC), the Institute of Marine Research of Vigo (IIM-CSIC) and the Oceanographic Center of Vigo of the Spanish Institute of Oceanography (IEO-CSIC) have participated. , has combined field samples collected by the IEO-CSIC and IIM-CSIC with images from the Sentinel-2 satellite of the Copernicus program of the European Commission and the European Space Agency (ESA). In this way, the team was able to identify and map in great detail during the summers of 2017 and 2021 in three Galician estuaries (Vigo, Pontevedra and Corme e Laxe) the red tides of two dinoflagellates, Noctiluca scintillans and Alexandrium , at a spatial resolution of 20 meters.
Thanks to this, they have developed a spectral detection index for these organisms, which can be applied both in Galicia and in any other region of the world. "As a complement to the studies with satellite images, it is necessary to collect more field data and for society to be always alert when there is a change in the color of the sea water, so that we can increasingly calibrate this methodology," he points out. Sacilotto .