Although the thermometers of the cities of Valencia and Malaga have hardly any differences, since both cities have reached over 40 degrees during the successive heat waves that have hit Spain this summer, the temperature of the water that bathes their coasts varies by up to 8 degrees, a situation may seem unusual as both cities are on the Mediterranean coast.
Thus, while the buoy that Puertos del Estado has in front of the port of Valencia has reached 28.7 degrees this July, the current temperature of the water in Malaga is just over 19, the head of Climatology of the State Meteorological Agency, José Ángel Núñez Mora.
Núñez Mora emphasizes that, in addition, the constant heat waves have caused the average temperature of the surface waters -20 miles from the coastline- in the Spanish coastal areas to be 24.6 degrees, "the highest recorded in waters coasts of Spain since at least 1940, exceeding the records of 2015 and 2022".
"The Mediterranean Sea is at all-time highs," says Núñez Mora, who nonetheless explains that there are great differences between some areas of the national territory and others, such as the Balearic Sea (maritime area between the coasts of Valencia, Castellón, Tarragona and Mallorca and Ibiza) and the Alborán, the westernmost part of the Mediterranean Sea that bathes the coast of Malaga.
The specialist indicates that "the current temperature in areas such as Tarifa or Algeciras is less than 18 degrees and the temperature in Malaga is just over 19", a fact that "contrasts strongly with the 28 ºC in areas of the Balearic Sea".
This deviation in the measurements is due to the exchange of water masses that take place through the Strait of Gibraltar, where the Atlantic Ocean, with its colder waters, comes into contact with the Mediterranean Sea, the researcher from the Institute of Coastal Ecology of El Campello (Alicante) and doctor in Biology, David Gras.
This cooling phenomenon occurs "because the water that enters the Mediterranean from the Atlantic comes from the surface, while the water that goes from the sea to the ocean goes in depth," according to the expert.
"In the areas closest to where the exchange occurs, which is the Alboran Sea, the effect of the Atlantic water is greater and that is why the water temperature in that area is lower," says Gras, who adds that the waters close to the Valencian Community are hotter because "they are back" after traveling a large part of the Mediterranean.
For his part, Núñez points out that these cooling due to the inflow of Atlantic water "do not reach the Balearic Sea" and adds that "that is why climatically (that area) is usually warmer than in coastal areas further south, although when the wind prevails east, the waters of the Andalusian Mediterranean also remain warm".
After the new temperature record registered in a month of July at the Valencia buoy, everything indicates that in August the historical maximum of 29.94 degrees will be exceeded in the waters near the Community, which dates from August 11 of last year. on a day in which the highest data for the Balearic Sea was also exceeded by four tenths, with 29.3 degrees, the highest figure recorded since the same month of 2003.
The researcher from the Institute of Coastal Ecology indicates that this "unusual increase" occurs due to "the continuity of heat waves, which move from the atmosphere to the hydrosphere, which is what is happening this summer and what happened in the previous".
The ever earlier arrival of summer heat also influences this phenomenon, since the water heats up "at the beginning of summer and not at the end," explains Gras, so "that water temperature drags along throughout three months, at least."
The almost habit of seeing how records and historical temperature figures are broken year after year makes them take for ordinary phenomena that are not, which have great consequences for the environment and ecosystems.
In this way, the increase in degrees in water temperature goes beyond a game of numbers and statistics, as it translates into changes in sea conditions over the years and its "tropicalization", which entails " environmental changes that are transferred to living beings and marine organisms".
Marine life can be threatened by "exotic invasive species that live in subtropical areas, warmer seas, and that can get here by currents, adapting perfectly because the sea temperature allows them to survive, thus representing a competitor to the fauna autochthonous, it can displace it", warns the researcher.
In addition to these effects on biodiversity, indirect changes are also originated, such as the erosion of the coastline derived from cold drops and storms that, according to Gras, arise "from excessive heating of water columns."
Likewise, the DANA typical of the Mediterranean areas of the peninsula will increase their frequency and power due to the greater evaporation of seawater, which entails rainfall and higher energy waves.
Thus, he concludes that 30 degrees will soon be exceeded in the sea off the Valencian coast and 20 degrees will be exceeded in the westernmost waters and closest to the Strait of Gibraltar in the country, thus shortening an ever smaller difference between the temperatures indicated by the thermometers. out and in the water.
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