Aerial view of La Manga, in a file photo. /
A scientific team points out that the concentration has decreased by 20% in the Mediterranean strip in the last twenty years, but it has increased off the La Manga area and at the mouth of the Segura
The concentration of chlorophyll in the Spanish Mediterranean has decreased by an average of 20% in the last two decades. However, some areas such as the coastal strip facing the Mar Menor and the mouth of the Segura River show an opposite trend, with increases of more than 3% per year, due to eutrophication processes caused by the influx of nutrients.
These are the conclusions of a team from the Spanish Institute of Oceanography (IEO-CSIC), belonging to the Plankton Ecology and Environmental Challenges group of the Oceanographic Center of Malaga, which has published a paper in which they analyze the variability of the surface concentration of the chlorophyll in Spanish Mediterranean waters during the last 20 years through satellite images, it indicates in a statement.
This study, published in the journal Remote Sensing Applications: Society and Environment, points out that chlorophyll concentration has decreased by up to 20% in the last two decades. Scientists point to strengthening stratification of the water column induced by surface heating as the most likely cause of this decline.
“The general decrease in the surface concentration of chlorophyll, which has been reported in many areas of the planet, can affect many important ecosystem processes, such as the ocean’s ability to sequester atmospheric carbon or the productivity of the entire marine food chain” , comments Francisco Gómez Jakobsen, main author of the work.
Despite this general downward trend in chlorophyll concentration, the study shows how in some regions, influenced by the influx of nutrients from the coast, the trend has been the opposite, even registering increases in concentration of more than 3% per year, points out the IEO. «This is the case of the coastal strip in front of the Mar Menor and the mouth of the Segura river. These significant increases, within a context of general decrease, could indicate processes of coastal eutrophication,” says Gómez Jakobsen.
Scientists have used novel analysis techniques based on data from different ocean color sensors capable of recording radiometric information on the surface layer of the water with an almost daily frequency and with high spatial resolution, making it possible to relate these data with the distribution and concentration of chlorophyll after applying an algorithm created specifically for the study area.
“This work is an example of the importance of having sufficiently long and high-quality time series of oceanographic data to be able to detect significant changes in the concentration of chlorophyll, which may in turn be indicative of the effects of climate change or pollution.” from terrestrial sources,” says the scientist.
This study has been carried out within the framework of the evaluation and monitoring of eutrophication in Marine Strategies financed by the Ministry for Ecological Transition and the Demographic Challenge, and the ECLIPSE project, financed by the State Research Agency. In its preparation, the Supercomputing and Bioinformatics Service (SCBI) of the University of Malaga collaborated.
Topics
CSIC, Segura Hydrographic Confederation, La Manga, Mar Menor, Scientific research, Environment, Posidonia, Segura River, Tajo-Segura transfer, satellite, Portmán Bay
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