In this New York Times article, biologist Dr. Kawaguchi explains his research into Antarctic krill populations. In his lab, he observed the effects of carbon dioxide being pumped into his lab simulation on the krill. He witnessed the carbon dioxide killing the eggs. The importance of this organism in the ocean ecosystem is due to the fact most marine life is a direct predator of krill or just one step removed. As krill stocks are diminishing, there is less food for squid, whales, seals, fish, penguins, and sea birds.

The reason for the krill dying off in such large numbers? Higher levels of carbon dioxide in the water resulting in greater levels of ocean acidification, explains Dr. Kawaguchi. “If we continue with business as usual, and we don’t act on reducing carbon emissions, in that case, there could be a 20-70% reduction in Antarctic krill by 2100 [and] by 2300, the Southern Ocean might not be suitable for krill reproduction.”

Dr. Rintoul, an oceanographer with Australia’s national science agency, explains “it is like a conveyor belt carrying heat and carbon dioxide to the ocean, this is one reason it can absorb so much heat, the key question is how the acidification caused by the update of carbon dioxide will affect ecosystems.” We learned in Module 5 that the chemistry of carbon in seawater is complex but it is crucial in understanding the way the global carbon cycle operates and explains why the oceans can swallow up so much atmospheric CO2 without having their own CO2 concentrations rise very much. However, this article is a great example of small disturbances in CO2 concentrations in the ocean making a large impact on the wildlife. The area where the krill are reproducing is in very cold water, we learned in the Module that cold parts of the oceans absorb more atmospheric CO2 than warm regions do. As oceans take up more carbon dioxide, this article explains how sea animals are finding it more difficult to build shells and exoskeletons. Dr. Kawaguchi explains that krill are known to be a remarkably adaptable and abundant animal, but he fears that the krill may not be able to adapt fast enough.

Changing the chemical composition of the ocean may be the result of human interaction with the atmosphere so we should be responsible for slowing the changes, conserving the ecology, and making sure species that are crucial to the food chain are not killed off because of anthropogenic reasons.

Reference: Innis, Michelle. “Warming Oceans May Threaten Krill, a Cornerstone of the Antarctic Ecosystem” 19 October 2015. New York Times. Retrieved from: http://www.nytimes.com/2015/10/20/science/australia-antarctica-krill-climate-change-ocean.html?_r=0