Scientists have found that a warming of water in the Southern Ocean by just 1 degree Celsius will have a huge impact on aquatic animals and plants. Some species will double their rate and volume of growth, which will affect the decline in overall biodiversity, according to a new study.
Previously, the only way scientists could study the effect of rising temperatures on small marine organisms that live on the seabed was through experiments in laboratories and experimental pools. But "it's quite remote from the natural environment," says Gail Ashton, lead author of the new study.
Instead, Ashton and her colleagues at the UK Antarctic Survey have spent 6 years creating technology that can heat a small test area of the real ocean by 1 and 2 degrees Celsius - a predicted rise in ocean temperature due to climate change over the next 50 and 100 years, respectively.
The heating device was placed 15 meters below the surface of the shallow Southern Ocean, and the researchers documented what happened to marine life in 9 months.
The scientists reported that 1 degree warming "significantly changed" the marine life at the bottom. One species of bryozoans (Fenestrulina rugula), a type of aquatic invertebrate, rapidly increased in abundance and eventually dominated the study area within 2 months, causing an overall loss of biodiversity. Coiled tubular worms also thrived in the 1 degree warmer area.
The response of marine life to a 2-degree rise in temperature was more varied, scientists say.
The scale of the change due to warming "surprised everyone," Ashton said. "We thought we would need a bit of statistical analysis to highlight the differences, but if you look at the photo, it's pretty clear that the state of marine life is very different in the test sites."
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Scientists plan to similarly study the impact of global warming in other parts of the world, including the Arctic. Knowing which species will be the winners and losers is key as we try to predict the impact of climate change on ocean life.