Pteropod Limacina Helicina. Courtesy of Russ Hopcroft, UAF.
New and jolting research published in the journal Oceanography show that the surface waters in the Chukchi and Beaufort seas have become more and more acidic. NOAA, University of Alaska, and Woods Hole Oceanographic Institution reached the conclusion that these high levels of acidification could threaten the ability of the base of the arctic food chain to form and maintain their shells. The research shows that the surface waters of the Chukchi and Beaufort seas could reach levels of acidity that threaten the ability of animals to build and maintain their shells by 2030, with the Bering Sea reaching this level of acidity by 2044.
“Our research shows that within 15 years, the chemistry of these waters may no longer be saturated with enough calcium carbonate for a number of animals from tiny sea snails to Alaska King crabs to construct and maintain their shells at certain times of the year,” said Jeremy Mathis, an oceanographer at NOAA’s Pacific Marine Environmental Laboratory and lead author. “This change due to ocean acidification would not only affect shell-building animals but could ripple through the marine ecosystem.”
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A form of calcium carbonate in the ocean, called aragonite, is used by animals to construct and maintain shells. When calcium and carbonate ion concentrations slip below tolerable levels, aragonite shells can begin to dissolve, particularly at early life stages. As the water chemistry slips below the present-day range, which varies by season, shell-building organisms and the fish that depend on these species for food can be affected.
This region is home to some of our nation’s most valuable commercial and subsistence fisheries. NOAA’s latest Fisheries of the United States report estimates that nearly 60 percent of U.S. commercial fisheries landings by weight are harvested in Alaska. These 5.8 billion pounds brought in $1.9 billion in wholesale values or one third of all landings by value in the U.S. in 2013.
The continental shelves of the Bering, Chukchi and Beaufort Seas are especially vulnerable to the effects of ocean acidification because the absorption of human-caused carbon dioxide emissions is not the only process contributing to acidity. Melting glaciers, upwelling of carbon-dioxide rich deep waters, freshwater input from rivers and the fact that cold water absorbs more carbon dioxide than warmer waters exacerbates ocean acidification in this region.
The worlds oceans are changing. Most of us, when discussing Climate Change, focus on how air temperatures are rapidly rising, drought and Sea Level Rise. The oceans have for the past 200 years done us a favor by absorbing roughly 50% of the carbon we have released into the atmosphere. The oceans continue to absorb 25%. The dissolved carbon in salt water causes a phenomenon known as ocean acidification. This acidic water is killing creatures at the base of the marine food chain throughout the world but particularly in the Arctic ocean. In the Arctic, the food web is small and simple and energy is channeled in just a few steps from small plants and animals to large predators like fish, seabirds, walrus, seals, whales and polar bears. The stability of such a simple marine ecosystem depends greatly on keystone species. Pteropods (sea butterflies) and echinoderms (sea stars, urchins) are key food-web organisms that are highly sensitive to acidification. Acidification is not the only problem for marine habitat though, huge volumes of sea ice melt, glacier melt, upwelling, overfishing, and trawling are also known to exacerbate ocean acidification in polar seas. Additionally, the indirect effect of changing sea ice coverage is providing a positive feedback to acidification as more open water will allow for greater absorption of atmospheric CO2.
Arlington Institute provides an overview on the probable extinction of Arctic plankton.
Plankton is a blanket term for many species of microorganisms that drift in open water and make up the base of the aquatic food chain. There are two types of plankton, phytoplankton and zooplankton. Phytoplankton make their own food through the process of photosynthesis, while zooplankton feed on phytoplankton. Zooplankton are in turn eaten by larger animals. In this way these tiny organisms sustain all life in the oceans. According to the NASA, phytoplankton populations in the northern oceans have declined by as much as 30% since 1980.[4] While the cause of this decline remains uncertain, there are several theories.
One theory points to global warming as the main cause.[5] Phytoplankton require nutrients obtained from the bottom of the ocean to reproduce. At the Earth’s poles, ocean water is colder at the surface than down in the depths. Therefore water from the bottom of the ocean rises to the top, carrying with it essential nutrients from the ocean floor. However, as the water near the surface becomes warmer due to climate change, less water rises from the bottom, resulting in less nutrients for the phytoplankton. This consequently hinders their reproduction processes.
Another theory suggests that carbon dioxide emissions are causing this decline in plankton population. The ocean has always absorbed a significant amount of carbon dioxide, but in recent years its capacity for this pollutant may not have been able to keep up with the level of human output. Recent studies suggest that the carbon dioxide the ocean absorbs is turned into carbonic acid, which lowers the pH level of the ocean.[6] This acidification is highly corrosive to sea animals that form shells, including pteropods, which are a type of zooplankton. Pteropods are a food source for countless larger animals such as salmon and cod. If they are unable to survive in an acidic ocean, then the entire ocean system will be threatened.
The frigid water of the polar seas are now the frontline of the most dramatic shift in ocean chemistry in millions of years. We are learning a lot about climate science. Marine scientists will obviously continue to study this most depressing of situations, so that we can learn what will happen to the other oceans on the planet and prepare ourselves for any possible adaption. We have reached the point where we are going to have to face situations that we do not want to face. It's difficult, if not impossible, to make this case to the human race. We have to battle the fossil fuel industry, the GOP, apathy as well as provide the blunt statement that we either destroy ourselves economically or perish. I am absolutely mortified because I am not sure that whatever we will do going forward is not going to be enough. If Ronald Reagan had not been elected and killed green energy decades ago we might stand a fighting chance. But that's the way the cookie crumbled. Let's make sure that in 2016 the country does not repeat that mistake again.