Sometimes it seems to us that climate change affects only the land: wildfires and terrible hurricanes are increasingly occurring, and droughts are destroying once-green landscapes.
But in fact, the oceans are undergoing the most dramatic changes, even if we do not notice it with the naked eye. In fact, the oceans have absorbed 93% of the excess heat caused by greenhouse gas emissions, and it has recently been found that the oceans absorb 60% more heat than previously thought.
The oceans also function as carbon sinks, holding about 26% of the carbon dioxide released into the atmosphere from human activity. As this excess carbon dissolves, it changes the acid-base balance of the oceans, making them less habitable for marine life.
And it’s not just climate change that is turning thriving ecosystems into barren waterways.
Plastic pollution has reached the farthest corners of the oceans, industrial pollution leads to a constant influx of heavy toxins into waterways, noise pollution leads to the suicide of some animals, and overfishing reduces populations of fish and other animals.
And these are just some of the problems that underwater inhabitants face. Thousands of species living in the oceans are constantly threatened by new factors that bring them closer to the brink of extinction.
We invite you to get acquainted with five marine animals that are on the verge of extinction, and the reasons why they ended up in such a situation.
Narwhal: climate change
Narwhals are animals of the order of cetaceans. Because of the harpoon-like tusk protruding from their heads, they look like aquatic unicorns.
And, like unicorns, one day they may become nothing more than a fantasy.
Narwhals live in arctic waters and spend up to five months of the year under the ice, where they hunt fish and climb up to the cracks for air. As the melting of the Arctic ice accelerates, fishing and other vessels invade their feeding grounds and take large numbers of fish, reducing the food supply of the narwhals. Ships are also filling Arctic waters with unprecedented levels of noise pollution, which is stressing the animals.
In addition, killer whales began to swim further north, closer to warmer waters, and began to hunt narwhals more often.
Green sea turtle: overfishing, habitat loss, plastic
Green sea turtles in the wild can live up to 80 years, swimming peacefully from island to island and feeding on algae.
However, in recent years, the lifespan of these turtles has been drastically reduced due to fish by-catch, plastic pollution, egg harvesting, and habitat destruction.
When fishing vessels drop massive trawl nets into the water, a huge number of marine animals, including turtles, fall into this trap and die.
Plastic pollution, which fills the oceans at a rate of up to 13 million tons per year, is another threat to these turtles. A recent study found that accidentally eating a piece of plastic causes a turtle to be 20% more at risk of dying.
In addition, on land, humans are harvesting turtle eggs for food at an alarming rate, and at the same time, egg-laying places are shrinking as humans take over more and more coastlines around the world.
Whale Shark: Poaching
Not so long ago, a Chinese fishing boat was detained near the Galapagos Islands, a marine reserve closed to human activity. Ecuadorian authorities found more than 6600 sharks on board.
The sharks were most likely destined to be used to make shark fin soup, a delicacy served mainly in China and Vietnam.
The demand for this soup has led to the extinction of some species of sharks, including whales. Over the past few decades, the population of some sharks has declined by about 95% as part of the global annual catch to 100 million sharks.
Krill (planktonic crustaceans): water warming, overfishing
Plankton, however crumbly, are the backbone of the marine food chain, providing a critical source of nutrients for various species.
Krill live in Antarctic waters, where during the cold months they use the ice sheet to gather food and grow in a safe environment. As ice melts in the region, krill habitats are shrinking, with some populations decreasing by as much as 80%.
Krill are also threatened by fishing boats that take them in large numbers to use as animal feed. Greenpeace and other environmental groups are currently working on a global moratorium on krill fishing in newly discovered waters.
If krill disappears, it will cause devastating chain reactions in all marine ecosystems.
Corals: warming water due to climate change
Coral reefs are extraordinarily beautiful structures that support some of the most active oceanic ecosystems. Thousands of species, from fish and turtles to algae, rely on coral reefs for support and protection.
Because the oceans absorb most of the excess heat, sea temperatures are rising, which is detrimental to corals. When ocean temperatures rise 2°C above normal, corals are at risk of a potentially deadly phenomenon called bleaching.
Bleaching occurs when heat shocks the coral and causes it to evict symbiotic organisms that give it its color and nutrients. Coral reefs usually recover from bleaching, but when this happens time after time, it ends up being fatal for them. And if no action is taken, all the world’s corals could be destroyed by mid-century.