The rise in sea level can cause the “marinization” of estuaries and promote the entry of invasive species that affect the food resources of the population, concludes a study by the Interdisciplinary Center for Marine and Environmental Research (Ciimar).
In a press release, the research center of the University of Porto points out that the study published this Monday, carried out in partnership with the Federal University of Bahia, in Brazil, reveals a “worrying analysis” on the impact of the rise sea level on estuaries. and the possible consequences of saltwater intrusion in coastal ecosystems.
Published in the journal Oceans and Coastal Management the study analyzed other scientific papers to develop a “predictive model” and anticipate the position of saline intrusion in estuaries in the face of the likely scenario of sea level rise in the coming years.
Using mathematical models, the researchers concluded that the combination of sea advance with extreme drought can lead to “amplified salinity penetration” into estuaries, because not only sea advance is greater, but the flow of rivers is also reduced.
“Sea level rise promotes the entry of saltier water, while the flow prevents salt water from rising too far upstream. Slow-flowing rivers naturally become saltier at high tide,” he said. he, quoted in the press release, the first author of the article, Youri Costa.
With the increase of extreme events “The challenges associated with large variations in salinity in estuaries increase both for the biodiversity about the people and [para a] the local economy”.
Under sea level rise scenarios, salinity penetration will tend to intensify and water evaporation may increase the salinity of estuaries, “causing estuary marinization”, a phenomenon already recorded in some places.
Invasive species can dramatically reduce the food resources of native species, outcompete them and drive them to extinction in these places.
invasive species
In this process, marine species that do not usually live in this ecosystem they begin to colonize it, an adaptation that researchers say “seems to have no consequences, but hides other problems”.
“It sets a precedent for opportunistic species, such as invasive species known to cause environmental imbalance,” he said. Yuri Coast.
The cause may be the arrival of invasive fish species in estuaries which, being more tolerant of stress that the native species, which are still adapting to the new conditions, cause a “situation of imbalance”.
“In this case, invasive species can drastically reduce the food resources of native species, compete with them and reduce them to extinction in these places”, observes Yuri Costa.
Another “worrying” factor, underlines the researcher, is that these species can affect the food resources, often of subsistence, of the surrounding human populations who do not have these invasive species as a target of capture and only perceive the decline of the species which traditionally used to capture.
Also quoted in the statement, researcher Irene Martins points out that the use of digital tools is “extremely important for the adoption of adequate measures for the preservation and conservation of coastal systems, such as estuaries and estuaries”.
“The study draws attention to the importance of adopting measures to mitigation and adaptation to minimize the impacts of sea level rise on estuaries, indicating useful predictive tools for public managers and decision-makers in planning adaptation measures,” he observes.
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