Story at a glance:
- When species fled warming waters for cooler temperatures 252 million years ago, 90 percent of marine life died.
- Scientists are concerned a similar extinction might happen again as sea temperatures rise.
- Species richness is greatest in the oceans near China, Mexico, Brazil and Australia.
Global warming is causing many marine species to flee their habitats around the equator, and it could cause mass extinctions, a new study from the Proceedings of the National Academy (PNAS) finds.
The marine ecosystem is literally in hot water; it is so hot that tropical tuna species, sea turtles, manta rays and whale sharks are escaping to cooler waters, and scientists are worried.
This pattern happened 252 million years ago, when global temperatures warmed by 10 degrees Celsius over a span of 30,000-60,000 years, a result of greenhouse gas emissions from volcanic eruptions in Siberia. As the sea warmed during the “mammoth rearranging of global biodiversity,” scientists say, 90 percent of all marine species were killed.
PNAS has examined distribution records of about 50,000 marine species dating back to 1955. Researchers found a correlation between animals moving to flee to cooler water towards the poles.
“For each of the 10 major groups of species we studied (including pelagic fish, reef fish and molluscs) that live in the water or on the seafloor, their richness either plateaued or declined slightly at latitudes with mean annual sea-surface temperatures above 20℃,” PNAS stated.
As of today, the southern oceans of China and Mexico and the northern oceans of Australia and southern Brazil have the greatest species richness in the northern and southern hemisphere in latitudes, respectively.
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