A new study by scientists into the future effects of acidic sea water shows that the reduced pH value of the oceans' surface waters will have drastic results in around 100 years' time. The scientists, from Sweden and Australia, carried out the world's first research into how a lowered pH of the sea's surface water affects marine animal life.
In their project, they allowed sea urchins of the species Heliocidaris Erythrogramma to fertilize themselves in water where the pH has been lowered from its normal 8.1 to a pH value of 7.7. This means an environment three times as acidic, and corresponds to the change expected by the year 2100.
The chemical balance of the sea has long been regarded as immovable. Today, researchers know that the pH of the sea’s surface water has gone down by 0.1, or 25 percent, just since the beginning of industrialization just over a century ago. The sea absorbs carbon dioxide from the atmosphere and acts as a giant buffer for the Earth’s life support system, by making up for our use of fossil fuels among other things.
University of Gothenburg researchers, Jon Havenhand and Michael Thorndyke, say that this acidification process of the oceans affects the sea urchin profoundly. Like most invertebrates, the sea urchin multiplies by releasing its eggs to be fertilized in the open water. However, in a more acidic marine environment, the sea urchin’s ability to multiply goes down by 25 percent, as its sperm swim more slowly and move less effectively. If fertilization is successful, their larval development is disturbed to the extent where only 75 percent of the eggs develop into healthy larvae.
"A 25 percent drop in fertility is the equivalent of a 25 percent drop in the reproductive population. It remains to be seen whether other species exhibit the same effect, but, translated to commercially and ecologically important species such as lobsters, crabs, mussels and fish, acidification would have far reaching consequences," says Jon Havenhand, a researcher from the Department of Marine Ecology working at the Sven LovÃ©n Centre for Marine Sciences in TjÃ¤rnÃ¶. The researchers wrote their findings up in an article published in Current Biology and entitled it Near future levels of ocean acidification reduce fertilization success in a sea urchin.
The sea urchin lives off the south coast of Australia. From a research point of view, the species is interesting as its shell is made out of limestone, which is broken down in more acidic environments. "Species with limestone skeletons or shells are hit particularly hard when the pH drops, through a drop in ability to grow and a rise in mortality. But, and it's a big but, we don’t yet know enough about the effects of acidification in the sea, and I hope I’m wrong about the wider consequences of our results," says John Havenhand, one of the researchers. He added that the need for more research on a global level is acute.
The project's findings add to series and series of worrying studies indicating that the world's oceans appear in serious trouble. Governments and organizations around the world appear to spend only few resources on salvaging the seas. For instance, the US government allocates something like $18,700 per square mile to the National Park System, and just $400 per square mile to its ocean counterpart, the National Marine Sanctuary System, according to an Intelligence Report just out on Parade.com.
The report reveals that private charities show a similar trend. "Close to 99% of conservation dollars donated go to land causes, and 1% to oceans," according to one source quoted in the report. Debra Erickson, executive director of the nonprofit Kerzner Marine Foundation (KMF) says that by contrast, over 70% of the Earth is covered by oceans.
The reason why this is might be that on the surface, literally, all looks well. But underneath, it's a different story.