Picture a world without polar bears or the Great Barrier Reef. The ocean is the lifeblood of our planet and altering the conditions of the water can destroy aquatic ecosystems. Rising temperatures and increased acidification are having major effects on marine life.
What does climate change mean for the world’s ocean-dwelling species?
Shells Are Dissolving
The ocean absorbs much of the greenhouse gases that humans create. When carbon dioxide dissolves in the water, it becomes carbonic acid. It can then erode the shells of animals like lobsters, crabs, and scallops.
The animals have to spend extra energy repairing and thickening their shells, which can make it hard for them to grow and reproduce. This isn’t just bad news for the shell-bearing species themselves – it also affects the animals that depend on them for food or shelter, as in the case of hermit crabs that inhabit snail shells.
Coldwater Species Are Migrating
Warming waters are forcing certain species out of their home range in search of cooler temperatures. One study predicted that, by 2030, 23% of shared fish stocks – meaning those species that live in territories shared by neighboring countries – will have migrated.
This creates the possibility of international disputes over fishing rights. Already, some northern U.S. states are catching a disproportionate number of lobsters that prefer colder waters. Tuna are shifting their range to the east of the Pacific Islands, raising concerns for Pacific Island countries that depend on the fish. And when mackerel recently showed up in Iceland for the first time, it started a conflict concerning who has the right to harvest them.
Corals Are Dying
Coral reefs have been referred to as rainforests of the sea. They provide a place for animals to hide, reproduce, and seek shelter from ocean currents. Infamously, ocean warming leads to coral bleaching. This is the process in which coral turns white and often dies, leading to a collapse in the reef ecosystem that depends on it.
Healthy coral supports a diversity of marine animals such as turtles, fishes, sea anemones, and crustaceans, and their disappearance could be disastrous for human populations that depend on them.
Krill Populations Are Dropping
Much of Antarctica’s sea ice is melting due to climate change. Because the ice forms a crucial habitat for Antarctic krill – shrimp-like creatures a little over two inches long – their numbers are dwindling. Many polar birds and mammals rely on krill as a food source, so their populations are declining, too.
The consequences could ripple up the food chain. As penguins die off, polar bears must look for alternative sources of prey, potentially leading them into further conflict with humans.
Jellyfish Are Thriving
One of Earth’s earliest animals to evolve, the jellyfish is flourishing under climate change. Due to warming waters, lower oxygen levels, and the overfishing of other marine animals, jellyfish have come to dominate parts of the ocean just as they did some 500 million years ago. This dramatic ecological shift is not without consequences.
Jellyfish can form vast swarms that clog seawater cooling filters at nuclear power plants. They can also congregate in such numbers that they damage fishing gear by overloading the nets. Additionally, people will come in contact with jellyfish more and more as their population continues to swell.
Our Blue Planet
Many people are aware of the effects of climate change on land. But for the majority of the Earth that’s covered in water, acidification, warming temperatures, and mass die-offs of marine species are the direst consequences. Slowing down climate change is the only surefire way to restore things to how they were – or, at the very least, prevent any further damage.
See more posts from Jane Marsh at environment.co
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