Global warming renders the oceans unable to absorb the heat generated by increased greenhouse gas emissions. But the rise in temperatures in the Mediterranean is so high that it triggers the formation of crystals which in turn emit CO2.
The warming of the seas and oceans triggers a cascade of side effects, among the best known: mergermerger ice, sea level rise, waveswaves from heatheat underwater and ocean acidification. But, according to the United Nations Department of Climate Action, more and more indicators show that the oceans are no longer able to absorb the greenhouse gases that accumulate in large numbers: they play less and less their role as climate regulators, in front of of an “overflow” of polluting particles.
The heat leads to the formation of carbonate crystals
This process is particularly evident in the Mediterranean: the sea would even enter a phase of stratification. it’s about separationseparation of water between multiple layers, a process seen in all the oceans and seas of the world. This stratification is characterized by three layers: a surface layersurface layera middle layermiddle layer and a deep layer. The more the heating increases, the more the layers prevent the water from mixing, changing the exchanges between the carboncarbonoxygen and others nutrientsnutrients.
However, the excessive heat of the eastern Mediterranean Sea during the summer prevents it from absorbing the gases and, even more so, it begins to release them. How ? As the stratification increases, the density differences between the oceanic layers also increase: this reinforced stratification leads to the formation of carbonate crystals, which emit CO2.
A phenomenon aggravated by microplastic pollution
15% of the gases emitted into the atmosphere above the Mediterranean Sea come from these crystals. A process that could accelerate due to two factors: the continuous increase in water temperature, but also the pollution that allows the crystals to aggregate. Increasing industrialization, coastal settlements and tourism have led to heavily contaminated waters in many coastal areas of the Mediterranean.
Because of the weak movementsmovements of the tidestides and currents in the region, pollution tends to remain close to its source in the Mediterranean and not dilute as it does in other seas and oceans. The authors assume that these crystals likely need a nucleus to form: polluting particles, particularly microplastics. The Mediterranean Sea is in fact one of the most polluted water bodies in the world by microplastics.