Ecologists in Action warns that “the serious situation of eutrophication” and the loss of depth are worsening
The massive influx of nutrients and sediments into the Mar Menor since last Sunday through the boulevards, as a result of heavy rains, has increased the risk of an episode of oxygen depletion (anoxia) and mass death of organisms due to eutrophication due to the contribution of organic matter. This was explained yesterday to THE TRUTH by the Professor of Ecology at the University of Murcia (UMU) Ángel Pérez Ruzafa, although, he clarified, “all this will depend on the amount of water loaded with nutrients that has entered or is entering.”
The Rambla del Albujón, the one that crosses through the center of Los Alcázares and others in Campo de Cartagena continued to pour brown water into the lagoon yesterday. They even came from areas without riverbeds, such as the center of Los Urrutias, in Cartagena, whose beach formed a river with rainwater from a large part of the town.
Pérez Ruzafa warned that the contributions of fresh water in recent days can create layers on the surface of the Mar Menor, which prevent the arrival of oxygen to the deepest areas, something that could cause the creation of areas with hypoxia, such as those detected before summer, after the rains of the past months of March, April and May.
Ecologists in Action warns that “the serious situation of eutrophication” and the loss of depth are worsening
Macroalgae growth
These climatic anomalies, together with the state of high concentration of nutrients already existing in the salty lagoon, form a perfect cocktail for the rapid growth of species such as macroalgae, and are the clearest example of the eutrophication process that the area has been experiencing for decades.
The Professor of Ecology warned that this type of climatic episodes will occur more frequently, due to climate change, so, in his opinion, the only way to prevent the entry of nutrients is to have infrastructures that prevent it. He sees them as feasible, but much more to reduce the water table, now at its highest point, which is what makes the contribution of harmful substances greater. That is why he proposes to start up the water extraction systems for the irrigation of the fields, yes, “in a regulated way”.
Pérez Ruzafa warns that climatic episodes like those on Sunday will be repeated “more frequently”
For its part, Ecologists in Action also warned of the “dire” consequences of the massive entry of farmland, fertilizers and other substances, dragged by the rains, into the Mar Menos, since they contribute to “worsening the serious situation of eutrophication” and to “loss of depth, due to filling”.
Land use change
The organization’s spokesman, Pedro Luengo, believes that these inputs of nutrients and sediments are not the fault of the rains, but of the change in land use in Campo de Cartagena, since where before there were rainfed crops, with terraces and vegetation that retained soil and water, there are now “thousands of hectares of intensively irrigated crops, flattened, constantly plowed, highly fertilized and without natural vegetation, which favors the water running on the surface, feeding the floods and dragging tons of land from cultivation and fertilizers to the Mar Menor.
In his opinion, the arrival of the sediments is “impossible to avoid and retain”, with cement infrastructures or mega centralized treatment plants. For all these reasons, from Ecologists in Action they insist that there is a broad scientific consensus that the measures to save the Mar Menor from these massive inflows of sediments and nutrients must be at the origin (transformation of the agricultural model).
He also added that Nature-Based Solutions are effective, since “it has been more than proven that they have better cost-effectiveness ratios, are more durable and, on top of that, they provide other extra benefits on biodiversity, landscape recovery and human health” .
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