Posidonia seaweed is in danger of extinction

In Tunisia, there is a risk of disappearance of Posidonia, a seaweed on which fishing and tourism depend, and an important sector of the country’s economy, due to ignorance of its role, illegal fishing and pollution, which worries scientists. “Tunisia has by far the largest seaweed ponds in the Mediterranean”, more than one million hectares, confirms Rym Zakama Serib, a marine environment researcher in Tunisia. These underwater forests, up to 50 meters deep, provide shelter for many species of fish. Leaves “Poseidonia Oceanica” They also help break the waves and thus keep the coast from drifting.

“The existence of all Tunisian economic activities depends on Posidonia, which is the largest provider of jobs in the country.”

Yassin Ramzy Saghir, marine biologist

In the Agence France-Presse

The expert cites in particular the fishing sectors (150,000 direct jobs) and tourism (tens of thousands).

A bundle of leaves, rhizomes and rhizomes, creeping stems buried in the ground In general, Posidonia grows very slowly, less than five centimeters per year. Thanks to the roots, the meadows store carbon and produce oxygen, which is why the name Posidonia “blue carbon”explain Reem Sereb’s momentum, indicating that it produces 14 to 20 liters of oxygen per square meter. According to the researcher, seagrass, which absorbs three times more carbon than the forest, can fix significant amounts over thousands of years. “In the context of climate change, we need Posidonia to capture as much carbon as possible,” There is a lot of Yassin Ramzy Al-Saghir, an expert in marine biology.

Tunisian marine biologist Yassine Ramzi Sghir inspects a Posidonia-like marine station in Tunisia, March 14, 2022 (FETHI BELAID / AFP)

Due to a lack of resources, researchers cannot quantify the destruction of lawns in recent years in Tunisia. But they point to multiple causes in a country where nearly 70% of the population lives on 1,400 km of coastline: human activities, coastal development, illegal fishing, and aquaculture farms built on the seagrass bed. ignorance of the general public and decision makers, “Seating” Posidonia washed up on beaches, for example, is often considered waste. Sometimes bulldozers are used to clear them, removing a lot of sand and speeding up erosion, according to researchers who say they fear nearly half of Tunisia’s beaches will disappear.

Even stranded on the beach, the “Seating” Posidonia protects the strands from swelling. It also improves water quality and transparency, making swimming more attractive to tourists, recalls Reem zakat sarib. In Tunisia, beaches are a major component of tourism, a sector that accounts for up to 14% of GDP depending on the year. However, 44% of the country’s beaches are at risk of erosion due to sea level rise. “We help hide the beaches by removing the benches”Ahmed bin Hamida, director of marine and coastal areas in the government agency for the protection and development of the coast (Abal), warns.

A fisherman reviews a marine plant, of the genus Posidonia, on a beach in Monastir, Tunisia, March 21, 2022 (Bachir Tayeb / AFP)

According to scientists, almost 40% of fishing activity also occurs in seagrass beds. A sector that represents 13% of Tunisia’s GDP. A 2010 study reported a significant decline in seagrass beds in the Gulf of Gabes (southeast) due to illegal fishing (bottom trawling) and pollution. Since the 1970s, chemical phosphate processing plants have dumped phosphate gypsum there. The result: less than 40% of the Posidonia meadows remain in this area, Yasin Al-Saghir regrets.

Even if he hunted in the north, in Monastir (central east), Mazen Majidichi fishes three times more than he did 25 years ago. “There are fewer and fewer of them in the shallow waters where Posidonia is,” Says the fisherman. Although aware of the importance of Posidonia, he understands his colleagues in particular “Young fishermen with sarcasm mean:”You are not looking for the interests of the sea but to feed your children and your family.”

“The sea is destroyed. The chemicals are lying everywhere. Our sea has changed.”

Mazen Majdishi is a fisherman

In the Agence France-Presse

Ahmed bin Hamida from Abal wants “Keep hoping that this treasure will be saved”, especially through “The prospective establishment of four marine and coastal protected areas: Galit Islands (North), Zembra (Northeast), Kiryat (Northeast) and Knys (East)”. But he warns: “If nothing is done to protect all of the posidonia, we are headed for a real catastrophe.”

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