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New Study Suggests Global Marine Food Chain Could Collapse

Two professors at the University of Adelaide in Australia recently released a study. The study warns that the world's fisheries and ocean ecosystems are under threat. The study concluded that the situation is worse than scientists had thought. Rising carbon dioxide is damaging ocean ecosystems. The global marine food supply could collapse (or break down).

The professors reviewed data from 632 published experiments. The study looked at waters from the tropics (stretching around the center of the Earth) to the arctic (the northernmost place on Earth). The experiments covered a range of ecosystems. These ecosystems included coral reefs (thousands of tiny animals living in colorful underwater systems), kelp (or seaweed) forests, and the open ocean. The study concluded that climate change will harm most marine species. Species are biological groupings of animals.

However, microorganisms such as plankton and algae are different. Scientists expect these very small organisms will increase in number and diversity.

Microorganisms provide food for marine herbivores (or animals that eat plants). But the food situation becomes less optimistic for bigger carnivorous (or meat-eating) marine life. These bigger creatures are the foundation of the global fishing industry.

image: an arrow points from big fish to small fish. big fish eat smaller fish, smaller fish eat even smaller fish, very small fish eat very very small fish and plants

Ivan Nagelkerken is one of the authors of the study. He is an associate professor at the Southern Seas Ecology Labs at the University of Adelaide. He says that marine life will experience “a species collapse (or breakdown) from the top of the food chain down." Commercial fishing resources could collapse in less than thirty years.

Mass die-offs of marine animal species

“No species can sustain itself in an environment where there's not enough food. And these effects are only exacerbated (or made worse) as you go up the food chain,” he said.

Nagelkerken worked with another University of Adelaide marine ecologist Professor Sean Connell. The study's conclusions surprised them. The conclusions were much worse than they had thought. They did not expect to see such strong negative responses across so many species.

It is not possible to immediately stop ocean warming and acidification. Even if all carbon dioxide emissions stop, the ocean will continue to warm for a long time. But, according to Nagelkerken, there are things humans can do to lessen the crisis.

image: marine life stressors. three images: image 1, trash floating in the ocean, text: ocean pollution, image 2, plants and algae grown in the water. the water is green and you can't see past the surface, text: excessive plant growth, image 3, a large fishing net pulls in a very large quantity of fish, text: overfishing

He says that if we reduce the number of local stressors, we can slow the process down. These stressors include pollution of the ocean, too much plant growth, and over-fishing. We should reduce the number of stressors. This will give ocean species a chance to get used to climate change.

Ocean acidification affects global climate

As the oceans warm, some species will swim to higher latitudes (or move north). But those who fall behind may not survive.

Warmer waters and increased acidification hurt habitat-forming species (or animals that create ecosystems). These are the small animals and plants that create habitats for larger animals. Coral, oysters, and mussels are examples of habitat-forming species. Any slight change in the health of their habitats will have a big impact on many species living in the reefs.

The study also predicts acidification will reduce the amount of dimethyl sulfide gas (DMS). DMS is produced by ocean plankton. It helps increase cloud cover which regulates the Earth's temperature. So, less gas means fewer clouds and more warming.

Source: © 2021 by FHI 360. "Intermediate Reading Practice: New Study Suggests Global Marine Life Could Collapse (Optional)" for the Online Professional English Network (OPEN), sponsored by the U.S. Department of State with funding provided by the U.S. government and administered by FHI 360. This work is an adaptation of "New Study Suggests Global Marine Life Could Collapse", by Steve Herman / VOA News available under Public Domain / U.S. Government Works. Adapted content is licensed under the Creative Commons Attribution 4.0 License, except where noted. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

Image Credits:

"Fishing down the food web, a North Sea perspective " by Hans Hillewaert via Wikimedia Commons under CC-BY SA 4.0
This work is a derivative of Image by giogio55 from Pixabay , Photo by Jordan Whitfield on Unsplash, and Chilean Purse Seine By C. Ortiz Rojas / NOAA via Wikimedia Commons under Public Domain / U.S. Government Works. This derivative is licensed under CC BY 4.0 by FHI 360 for use in the OPEN program, sponsored by the U.S. Department of State with funding provided by the U.S. government and administered by FHI 360.