The daily average set a new record temperature of its surface Mediterranean in mid-August reaching 28.9°C and surpassing the previous year’s record, Spain’s main marine research center announced.

According to climatebook.gr, the highest prices are found in the central and eastern regions of the Mediterranean basin. The sea surface temperature in these areas fluctuates from 29°C – 31°C, while the deviations from the normal levels for the season locally exceed 5°C in the Adriatic Sea and 2-4°C in the southeast. In addition, high values ​​of the sea temperature are also observed in the Ionian sea with the temperature locally reaching 29°C.

Sea heat waves are becoming more and more frequent

As the Ph.D. in Physical Oceanography and principal researcher of the Hellenic Center for Marine Research (ELKETHE), Dimitris Velaoras, reports to the Athenian-Macedonian News Agency, studies carried out since the 1980s show that in the part of the Aegean and also in the area east of Crete , “in the Levantine that is”, it is noted per decade rise in temperatureof the sea surface of the order of 0.5 degrees.

At the same time, they are increasingly common sea ​​heat waves in the Mediterranean (Mediterranean Marine Heat Waves), a phenomenon which, however, according to Mr. Velaora, is of short duration. As he points out, the heat waves in the atmosphere affect the first approx 10 meters of the surface of the sea increasing its temperature up to 5 to 6 points.

“Just as heat in the atmosphere is a transient phenomenon, so is it in the sea. That is, the temperature will rise and at some point it will begin to decrease to return to normal levels. The point is that these sea heat waves have been occurring more and more frequently in recent years. Just as it happens with heat waves in the atmosphere. And this is one shock to the ecosystem“, underlines Mr. Velaoras.

The consequences of rising sea temperatures

One of the main consequences of the increase in the temperature of the Mediterranean sea surface is the entry of alien species from the Red Sea disrupting and affecting essentially the entire ecosystem.

The most classic example is lionfish and the lagocephalusas well as some species of sea urchins as well as the sardelogaur.

As Mr. Velaoras points out, if the conditions in the Mediterranean begin to “approach” those of Erythra, which has a temperature that can reach up to 35 degrees, then all the fish that passes through the ships, from Suez to Mediterranean will be able to find a good habitat to live”.

The continued rise in temperature can make deep water oxygenation difficult

According to the professor, on the one hand, the continuous rise in temperature affects the ecosystemson the other hand on a large scale it can also affect the stratificationthat is, to make it difficult to oxygenate deep waters.

This means that it is difficult to move the water from above, below, in a cold winter which can lead after some decades to the reduction of oxygen.

“If it decreases too much you will have a problem again in the habitats. That is, it will not be possible to sustain life in the deeper layers. There is a risk that in the coming decades, if the rise of the sea continues, this stratification will become more intense, that is, it will be more difficult for the surface waters to go to the bottom and oxygenate it”, he says.

In parallel with the increase in the temperature of the sea surface it is observed that the salinity of the water also increases while the phenomenon of sea level rise is increasing, but to an extent that is not yet alarming.

“For me the most critical thing about warming is what’s happening on a large scale because of climate change, which is the rise of 0.5 degrees per decade. “Marine heat waves are important, but they are shorter-term episodes, although of course they can have very significant effects on a local scale”, underlines Mr. Velaoras to APE-MPE.