So far, the Antarctic Weddell Sea has been little affected by environmental destruction and is therefore a habitat for many animals. Orcas, humpback whales and blue whales are just as at home there as penguins and various species of seals. Antarctic petrels breed on the coasts of the sea and a third of all emperor penguins are born there. A unique ecosystem that is increasingly threatened and should therefore be protected.
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The food cycles in the Weddell Sea depend on the ice sheet, which covers up to 75 percent of its surface during the Antarctic winter. Ice algae and bacteria grow in this ice, which serve as a food source for the zooplankton: microorganisms such as krill, floating shrimp or amphipods. The zooplankton, in turn, are eaten by fish, penguins, seals and whales. Leftovers trickle down to the sea floor and provide it with nutrients.
According to the Alfred Wegner Institute (AWI), which operates a research station in the Weddell Sea, around 14,000 animal species live there. The biodiversity is comparable to that of tropical coral reefs. At the bottom of the polar sea, creatures such as glass sponges, cnidarians, soft corals and sea squirts grow so densely that they form meter-high underwater forests.
Stable population of penguins
Because the region has hardly been developed, new natural wonders are constantly being discovered there. Last year, researchers from the Alfred Wegener Institute came across the largest contiguous fish breeding area in the world at the bottom of the Weddel Sea, with around 60 million nests of ice fish. Icefish are an example of how animals can adapt perfectly to the harsh living conditions in the Antarctic: their organism forms antifreeze proteins that prevent the blood from freezing.
Adelie penguins jump into the water.
© Source: Zuma Press
“The Weddell Sea is one of the last refuges for many animals, such as the Adelie penguin,” says Franziska Saalmann, marine biologist at Greenpeace. The crew of the Greenpeace research ship “Arctic Sunrise” made a discovery in the Weddell Sea earlier this year: the population of Adelie penguins there has remained stable in recent years. The number of animals in the observed colonies was similar to the last evaluation ten years ago.
Double threat from climate change
But the Weddell Sea is also gradually coming under pressure, says the Greenpeace expert. Climate change could even damage it twice: its ecological balance threatens to be upset when temperatures rise and the ice recedes. At the same time, this will make larger parts of the area accessible for fishing.
Greenpeace sees krill fishing as the main problem here. The tiny crustaceans are coveted for their omega-3 fatty acid content. They are processed into nutritional supplements or into fish feed for aqua farms. But in the ecosystem of the Weddell Sea, krill has an important function: whales, penguins and seals eat it. And the krill has another important meaning, explains marine biologist Saalmann. “Krill feeds on algae and absorbs the CO₂ it contains. With the excretions of the krill, this is bound as carbon and sinks to the sea floor. It is stored there for up to 100 years.”
Weddell Sea contributes to climate protection
According to one WWF report In this way, around 23 megatons of CO₂ equivalents are removed from the atmosphere in the Antarctic every year. Environmental protection organizations such as Greenpeace also consider the preservation of the ecosystem in the Weddell Sea to be important because it contributes to climate protection. They are campaigning for a protection zone with a fishing ban on an area of 2.2 square kilometers in the Weddelmeer, which would be the largest marine protected area in the world. Many states, including Germany, support the demand. At the conference of the Antarctic Commission CCAMLR, which is currently taking place in Hobart, Tasmania, the establishment of such a protection zone is to be discussed again. So far, the project has always failed due to the veto of China and Russia.
Julian Gutt, a marine biologist at the Alfred Wegener Institute, also thinks a fishing ban is right. Ideally, this should apply to the entire Weddell Sea. According to Gutt, krill fishing plays a subordinate role here: “The main distribution areas of krill are elsewhere,” says the professor. In recent years, however, fishing for Antarctic hake has increased in the Weddell Sea. “The hake is already sensitive to the climate, so there is no need to further damage the stocks through fishing.”
Fishing ban would protect ecosystem
The Antarctic hake fetches high market prices as a food fish. But in the Weddell Sea, seals and other sea creatures feed on it. Also, to fish for hake, longlines would be used, miles of fishing lines with side branches that are dragged along the seabed. When used correctly, this method is considered gentle. “But if the cords lay across the floor, everything there would be scalped,” criticizes Gutt. No market economy is dependent on the hake fishery in the Weddell Sea. “If you ban them, it doesn’t do much harm,” says Gutt. “At the same time, this could protect an important ecosystem.”
Like Greenpeace, the World Wildlife Foundation (WWF) has long advocated a protection zone in the Weddell Sea. “The establishment of marine protected areas in the Southern Ocean would ensure, above all, that direct human activities in these areas are strictly regulated or completely prohibited in certain areas of the protected areas,” Tim Packeiser, marine protection expert at WWF Germany, told the editorial network Germany. “Especially the ever-growing commercial fisheries must be regulated more strictly so that the food base for the marine species in the Southern Ocean is preserved in the long term.” Protected areas also acted as a kind of buffer with regard to the climate crisis: “The unique marine ecosystems of the Southern Ocean together with their biodiversity would be given the chance to adapt to the consequences of climate change without being affected by other disruptive factors,” says Packeiser.