Marine life is on the move. A groundbreaking study shows that over the last several decades as a result of warming ocean temperatures, many marine species are shifting closer and closer to the poles. Some types of fish and plankton are moving at a rate of 45 miles per decade. This is 12 times faster than terrestrial animals. As the base of the marine food web shifts toward the poles, larger animals are following as well, including people.
"That's like moving the dinner plate to a totally different place in the ocean," said paper co-author Benjamin Halpern, a research biologist with the National Center for Ecological Analysis and Synthesis at the University of California, Santa Barbara. The result is an abandonment of habitat and fishing grounds in tropical waters, and an overcrowding of non-native species in the fragile ecosystems of the polar oceans.
But the poles may not be the most hospitable place for marine life in the near future. Because colder water naturally absorbs more carbon dioxide than warmer water, the poles are especially vulnerable to ocean acidification. A more acidic ocean may wipe out Antarctic krill, a vital prey species that supports most of the Southern Ocean food web. Instability at the base of the food web from acidification, combined with overcrowding from an influx of animals fleeing from warmer waters, could lead to ecological collapse.
It was previously believed that animals on land would be more responsive to climate change, but this paper shows that even small changes in ocean temperatures are having a severe impact on marine life. "What these data show is that marine ecosystems are responding to environmental change, and they're responding at a faster rate than just simple metrics like mean global temperature rise would perhaps indicate," said Pippa Moore, another co-author and professor of aquatic biology at the Institute of Biological, Environmental and Rural Sciences at Aberystwyth University in the United Kingdom.
Society should be concerned by these findings. The results further support that ocean-based food security is threatened in a high CO2 world. The changes may reduce the amount of wild caught seafood that can be supplied by the oceans and also redistribute species, changing the locations at which seafood can be caught and creating instability for ocean-based food security. The least developed tropical nations where residents eat large quantities of fish, and lack resources to adapt, may suffer the worst hardships from climate change and ocean acidification.
While the impacts of climate change and ocean acidification on marine ecosystems, livelihoods, and food security are disturbing, there are steps that we can take to minimize these impacts. Please help Oceana combat climate change and ocean acidification and support clean, renewable energy sources like offshore wind, so that the ocean’s dinner plate, and our dinner plate, stays right where it is. Thank you!