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Cornerstone krill under threat from global warming

Krill, which form a vital cornerstone of ocean ecosystems, may be under threat due to ocean acidification. This acidification is caused by global warming, and could disrupt the krill's lifecycle.

krill, ocean acidification
"Meganyctiphanes norvegica2" by Øystein Paulsen - MAR-ECO. Licensed under CC BY-SA 3.0 via Commons - https://commons.wikimedia.org/wiki/File:Meganyctiphanes_norvegica2.jpg#/media/File:Meganyctiphanes_norvegica2.jpg

The world’s oceans are warming according to many scientists. According to the EPA, the layer of ocean waters is now warming at a rate of .2 degrees Fahrenheit. Given how fragile ocean ecosystems are, this could wreak havoc. Indeed, experts are warning that vital krill populations in the southern oceans are under threat.

Krill are tiny ocean crustaceans, and are part of the “base” for many ocean ecosystems. Just as many land herbivores depend on grass, and many predators, in turn, depend on these herbivores for food, entire oceanic food chains depend on krill.

Even the massive blue whale, the largest known creature to ever exist on earth, and also massive whale shark, depend on krill. These tiny crustaceans are members of the plankton family of tiny organisms that form a sort of “grass of the sea.”

The biggest threat to krill is currently in the southern Antarctic ocean, where increased acidification caused by carbon dioxide absorption appears to be disrupting the krill’s life cycle. Researchers believe that fewer krill are reaching adulthood, with larvae failing to survive, and/or eggs failing to hatch.

Dr. So Kawaguchi, a researcher for the Australian government, has warned that “if we continue with business as usual, and we don’t act on reducing carbon emissions, in that case, there could be a 20 to 70 percent reduction in Antarctic krill by 2100. By 2300, the Southern Ocean might not be suitable for krill reproduction.”

While 2100 might seem like a long way off, any substantial reductions in krill populations could disrupt fragile ocean ecosystems. Many of those fish and other ocean going animals that don’t consume krill directly, eat animals that do consume krill.

If those prey animals die off due to a lack of krill, animals up the food chain will almost certainly starve too.

Right now, the krill are facing a threat not just from global warming, but also overfishing. Each year, massive industrial fishing operations suck up thousands of tons of krill in a single fishing season.

In the past, such operations might have been sustainable, but with so many krill dying before they reach adulthood, researchers fear that the tiny crustaceans won’t be able to cope.

As of right now, fears of a declining krill population is based primarily on laboratory studies. Dr. Kawaguchi and his team simulated increased acidification of krill in a lab setting, and found that carbon dioxide disrupted the early stages of the krill’s life cycle.

Whether or not the same results will be observed in the larger ocean remains unknown.

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