Climate Change Causes Algae to Grow Faster
By Julie S | Jan 18, 2014 08:21 AM EST
A new study found that climate change affects the growth of algae in the temperate coastal waters in the Pacific Ocean.
The study focused on the crustose coralline algae, a species of algae found in the waters of Tatoosh Isalnd in Washington. Corraline algae's skeletons are made of calcium carbonate, just like the skeleton of other marine species like oysters and mussels. The researchers have been studying the marine ecosystem in Tatoosh Island for decades and they have gathered extensive ecological data on the site.
For this study, the researchers transferred the species of crustose corraline algae to their test sites to discover how increased salinity affects their growth and how they compete with each other.
Their experiment revealed that as the water absorbs more amounts of carbon dioxide from the atmosphere, the acid levels of the water also increases. Once this happens, species of shellfish and algae will find it hard to build their skeleton and shells. This phenomenon could be clear indication on how increased levels of acid in the water affect the marine ecosystem.
"Coralline algae are one of the poster organisms for studying ocean acidification," said PhD candidate in the Department of Ecology and Evolution at the University of Chicago and lead study author Sophie McCoy, in a press release. "On one hand, they can grow faster because of increased carbon dioxide in the water, but on the other hand, ocean acidification makes it harder for them to deposit the skeleton. It's an important tradeoff."
On the other hand, results for showing the competition among different species showed that Pseudolithophyllum muricatum is no longer the dominant species. McCoy's experiment reflected that P. muricatum won less than 25 percent of the time and no other species were found to be dominant.
McCoy explains this by the thinning of the skeleton of the P. muricatum. Before, data showed that P.muricatum was the dominant species due to their thick skeleton but according to McCoy's experiment, P.muricatum's skeleton is now half as thick as they were years ago. According to the researchers, this might be likely due to the decreasing pH levels of the waters recorded for over the last 12 years.
"The total energy available to these organisms is the same, but now they have to use some of it dealing with this new stress," she stated. "Some species are more affected than others. So the ones that need to make more calcium carbonate tissue, like P. muricatum, are under more stress than the ones that don't."
McCoy said that it's important to continue studying the effects of increased ocean acidification in a context like the one found in Tatoosh Island instead of artificial study sites in laboratory.
The study was published in the Jan. 15 issue of Ecology Letters.