Sun-spangled seabed of the Mediterranean sea. Image: European Commission

The Eastern Mediterranean is turning rapidly into a desert for native species, according to recent scientific studies that show how rapidly rising sea temperatures are devastating local marine life.

“The region is a climate change hotspot,” said Dr Gil Rilov, from the National Institute of Oceanography, Israel Oceanographic and Limnological Research in Haifa, Israel.

“The sea is getting warmer at ten times the global average rate.”

Scientists report that this appears to be killing off native marine life at an alarming speed – and rapidly changing the Eastern Mediterranean from temperate to tropical.

This, in turn, is making the sea more habitable for invasive species, which are changing parts of the sea from a carbon sink to a carbon producer as native seaweeds that soaked up emissions are destroyed.

Tackling this massive environmental challenge is especially difficult, with the region and its seaboard home to a range of conflicts.

“The Eastern Mediterranean already has a lot of problems,” Ahmed El Droubi, senior campaigner at Greenpeace Middle East and North Africa, an environmental advocacy group, said.

“Injustice, hardship and suffering for many here just compound the impact of climate change, making it very difficult to find sustainable policies to combat this.”

Plastic waste in the Mediterranean Sea. Image: iStock

While some hope remains, this collision of environmental meltdown and political conflict means stretches of the Eastern Mediterranean are witnessing multiple species extinctions.

Dr Paolo Albano from the University of Vienna’s Palaeontology Department said, “If we don’t go further in our actions to combat climate change we will just worsen the situation – and I don’t see how that old, temperate sea can survive.”

Along the reef

Both Albano and Rilov took part in a 2020 study, recently published by the UK’s Proceedings of the Royal Society B Journal, off the coast of Israel.

The study produced some alarming results. Looking at populations of mollusks – shelled sea creatures – the two scientists found a devastated sea floor.

“In a previous study in my lab, we investigated the disappearance of sea urchins along on shallow reefs on the Israeli coast,” says Rilov.

“While in 1976, there were about 10 urchin every square meter, today there were zero. Similarly, many native Mediterranean molluscs could not be found, while mostly invaders were found.”

The main driver of this is probably climate change, with the Eastern Mediterranean experiencing a dramatic rise in sea temperatures in recent years. These rose around 3oC between 1980 and 2013, with surface thermometer readings now regularly reaching 32oC.

The international Paris Agreement on climate change aims to restrict global rises to just 1.5oC. Most of today’s Mediterranean marine creatures originated in the colder Atlantic Ocean and entered the Mediterranean during recent geologic times.

Life in the Mediterranean is therefore accustomed to temperate waters. While species can usually adapt to gradual changes, the accelerated hike of recent years has pushed many beyond their ability to survive.

“Many Mediterranean species were already at the limit of their tolerance and then the temperature rose 3 degrees more,” says Albano. “This is pushing many species to eradication.”

Consumers to producers

One of the disappearing mollusks is also partly responsible for building the reefs found along many regional shorelines.

These reefs provide an important aquatic ecosystem for other sea creatures. The collapse of the reef-building snail may kill off these sea creatures in the future, as rising sea levels may drown the reefs.

At the same time, the sea is seeing an invasion of tropical rabbitfish.

These either swim up the Suez Canal from the warmer Red Sea and Indian Ocean, or are sometimes ejected into the Eastern Mediterranean by globe-trotting ships emptying their bilges.

The rabbitfish are now devastating native brown algal forests that provide a habitat and food for many native species. This turns the reefs into aquatic deserts that are being rapidly filled by invasive tropical algae.  

A diver observes filamentous algae locally known as Thanatos in the National Park of Port-Cros in the Mediterranean sea, near the island of Porquerolles. Global warming these past years has caused a major algal bloom on the seabed, suffocating flora and causing important biodiversity changes. Photo: AFP/Boris Horvat

This, in turn, is changing the shallow reef ecological communities from carbon sinks to carbon producers, as native seaweed species that can soak up emissions disappear.

“You get a shift from a reef being a carbon sink and oxygen producer to the reverse,” says Rilov.

The result is an accelerating process of climate change, as more carbon remains in the atmosphere, hiking global temperatures further.

Multiple pressures

At the same time, the Eastern Mediterranean suffers from a range of other environmental challenges.

Intense industrialization, rapid population growth and extensive land conversion characterize all of its littoral states – Turkey, Cyprus, Greece, Syria, Lebanon, Israel, the Palestinian Territories and Egypt.

Turkey, which has the longest coastline of all, is a particular contributor of a further scourge of the seas: plastics.

“Since 2004, Turkey’s plastic imports have increased by 173 times,” says Nihan Temiz Atas, Greenpeace Mediterranean Plastic Project development officer. “This is a very heavy burden for the Mediterranean.”

A 2019 survey showed that some 44% of the fish in Turkish waters had microplastics in their stomachs. The same was true for 91% of mussels.

The Covid-19 pandemic has created twin environmental and health crises as more plastics are used for hygiene purposes, Atas says. “When we are done with the outbreak, the excessive plastic pollution will be on our hands.”

Plastic waste is overwhelming the Mediterranean Sea. Image: Facebook

Over-fishing is also an issue, along with other forms of pollution ranging from industrial and agricultural run-off to raw sewage.

Albano says, “All these put extra pressures on species living in the sea already under the pressure of rising temperatures.”

Taking action

In terms of coordinated action on the environment, the Eastern Mediterranean lags some way behind the Western Mediterranean.

A major obstacle to cooperation here is that there are multiple disputes over a range of political and security issues. Maritime boundaries are also disputed between Turkey and Greece, and Cyprus, Israel and Lebanon.

“At the regional level, collaboration even in areas that are mutually beneficial is scarce,” says Droubi.

In the region’s European Union states, which are obliged by EU policy to prepare Programs of Measures (PoMs) for their marine environments, climate change is not even mentioned in Greece’s PoM. In Cyprus, it is mentioned but no clear countermeasures are listed.

With the sea temperature rising and destruction of native species so far advanced, “In climate hotspots like ours, we have to think about what we want to protect and how,” says Rilov.

Encouraging the fishing and consumption of invasive species may be part of this. Rabbitfish, known as kourkouna in Greek, are already a local dish in Cyprus.

Another response might be to identify “climate refuges.”

“At the global, or at least Mediterranean scale, there are places where temperature rises are not so high,” adds Rilov. “We need to identify where these are and perhaps focus on them.”

Rilov adds, “We need to do something very quickly to change our behavior. We are already way further down the road than we should be.”