The Mediterranean Sea is the most infested sea on the planet. There are more than 1000 exotic species from other ecosystems.According to the report, those who have found their new homes in this basin in recent years Impact of climate change on the Mediterranean Produced by the World Wildlife Fund (WWF).
This is the result of a summary of the factors that came together and continued in Mare Nostrum. from the effects of climate change to the intense maritime trade of this geostrategic region.a, as it is the union of three continents. The natural physiognomy of this closed sea also affects. All this increases the threat to endemic Mediterranean species and contributes to the proliferation of exotic animal and plant species.
The Mediterranean is warming, and it is doing so more and more rapidly. Specifically, The temperature rise is 20% faster than the global average and is currently one and a half degrees higher than the average for pre-industrial times. (1880), according to the report Risks associated with climate change and environmental changes in the Mediterranean region, Produced by the MedECC network.
Similarly, researchers from the Mediterranean Climate Change Group of the Spanish Institute of Oceanography (IEO), along with experts from the Balearic Islands Coastal Observation System (SOCIB) and the Barcelona Institute of Marine Sciences (ICM-CSIC), add another piece of information: this temperature rise is precisely placed at two degrees per century.As noted in a study published in the journal Frontiers in Marine Science.
Thus, the Mediterranean is moving towards tropicization and becoming an increasingly comfortable area for new types of warm waters, but less hospitable to those needing cooler waters moving to more northerly latitudes.
Marine Science Institute-CSIC researcher Pere Abello describes it as “natural movements” of species that have occurred since the first ice ages and are now perpetuated by the instabilities of climate change, increasing species availability. exotic species and the displacement of autochthonous and endemic species.
“If a species likes cold water and the water gets warmer, what it does is naturally go north. They’re looking for their optimal temperature. This is a fact we’ve been observing especially in recent years,” he explains.
closed sea
However, if the Mediterranean is a semi-enclosed sea, connected to the Atlantic by the Strait of Gibraltar and to the Black Sea by the Bosphorus, native marine species have little room to find new places, so their survival is threatened if they fail to adapt. “The cold-water species, if they go north, meet the coasts of France or Italy. They either adapt or die from the heat. Meanwhile, African species can enter through the Strait of Gibraltar”, continues Abelló.
“They can also migrate deeper, but there are some that need light, such as all plant species, algae, seagrass and even some corals, because the depth they can reach is limited by the light that reaches them. Mediterranean Institute for Advanced Studies (IMEDEA-CSIC) researcher Núria Marba said that this is closed He adds that being a sea has consequences, especially for native species.
Suez Canal
In 1869, the Suez Canal, a 163-kilometer artificial road connecting the Mediterranean to the Red Sea, was opened. Two centuries later, this route has become a key element for international trade as it connects Europe and Southeast Asia without having to travel across Africa.
Beyond commercial successes, the construction of this canal also The largest gateway for species currently living in the Mediterranean Sea from the Red Sea and Indian Ocean. An example is the rabbitfish, of subtropical origin, green, light brown and yellow, with venomous spines on its dorsal fins.
“These species normally stayed in very warm waters in the region of Egypt, Israel, Turkey, Greece, but did not reach the western Mediterranean region. what happens The waters of the Mediterranean have been warming considerably, especially in the last decade, clearly under the influence of climate change.Species that have been resident in the eastern Mediterranean for more than a century have already arrived or are coming,” adds Abelló.
ballast water
Ballast water is one of the most effective ways for invaders to enter the Mediterranean. used to stabilize ships carrying goodsyes So ships fill tanks mounted inside the hull in a controlled manner and are loaded and unloaded as needed.
“In salty and warm waters, the boat floats more, it has to take in more water to maintain its balance, and it also needs to release water in cold waters,” says the researcher.
Due to the globalized commercial structure, it may happen that a ship loads ballast water tanks in Florida and unloads them, for example, near the coast of Spain or Greece, which creates an excellent international distribution system for larvae and small organisms. .
Fish, crabs and algae: new hosts
this Caulerpa cylindracea, A green algae native to Southwest Australia, it is believed to have been introduced through the hobby of fish farming and the marine and aquarium.
According to the International Union for Conservation of Nature (IUCN), it is one of the 100 worst invasive species in the Mediterranean, as it has the ability to alter the physical and chemical conditions of the natural environment.
Same way, Lophocladia lallemandiia fibrous red algaetakes its place ocean of posidoniaa fundamental species in the face of climate change, as it acts as a carbon dioxide reservoir.
However, not all exotic species have adverse effects on the ecosystems in which they were introduced. This situation Halophila stipulacea, It contributes to the sequestration of CO2 in the Mediterranean. This was the result of an international study by IMEDEA (CSIC-UIB) that examined the effects of this plant species coming from the Red Sea and the Indian Ocean through the Suez Canal and colonizing the eastern and central Mediterranean. beach.
” halophile It is a very small plant that grows in places where native plants have disappeared or where there were no plants before,” explains Núria Marba, a researcher at the Mediterranean Institute for Advanced Studies (IMEDEA-CSIC).
“What we’ve seen is that they’re important in burying carbon. It can create carbon sinks like other seagrass meadows we have in the Mediterranean, such as Posidonia.”
Among the exotic animal species found in the Mediterranean, two stand out. this lionfish It is characterized by its prominent white and red stripes and venomous spiny fins. It comes from the Indo-Pacific. «The glutton is a predator, very similar to the scorpion fish we have here. It’s causing problems in Greece and Turkey,” says Pere Abelló.
another exotic rabbit fish, also poisonous, with shades ranging from brown to greenish gray and light brown to yellow. Its origin is in the Red Sea and the Indian Ocean.
It has very venomous spines that can be deadly, thus posing a risk to sport fishing and a handicap for tourism in coastal areas.
“If a fisherman catches it, it cannot be marketed. You have to be careful,” warns the researcher from the Marine Sciences Institute.
As far as crustaceans are concerned, Abelló, american blue crabAs one of the most troublesome species from the coasts of North and Central America (also found in Brazil to a lesser extent).
It has already been detected in the western Mediterranean, on the Mar Menor de Murcia, although without significant impacts, and in the Ebro Delta, where significant populations have been created.
“This is a species that is being mitigated through hunting. Although normally found in areas with a certain salinity, it is found in brackish water areas as well as in freshwater upstream,” explains the researcher. “It has a very complex reproductive cycle and a very high fertility rate that makes it a difficult species to eradicate.”
Source: Informacion
