A new study warns ocean acidification could change how the marine food chain operates due to its impact on phytoplankton communities.
Phytoplankton are at the bottom of the food chain, so their role in the marine ecosystem is extremely significant, the University of Alabama at Birmingham reported.
"Because phytoplankton types are not physiologically interchangeable, changing which species are most common in a community can impact the cycling of elements, the flow of nutrients and energy through the marine food web," said University of Alabama at Birmingham researcher Jeffrey Morris. "The implications could be substantial."
The decline in ocean pH, also known as ocean acidification, is caused by rising atmospheric CO2 levels. The ocean has observed about 30 percent of man-made CO2 emissions, causing a dramatic drop in the pH.
To make their findings, a team of researchers looked at phytoplankton populations under typical and elevated pCO2 levels, and observed a variety of results. Under eelevated pCO2 levels, some of the phytoplankton populations grew quicker while others grew more slowly, but all were altered in some way.
"One of the striking things about this work is it shows that all phytoplankton groups will be affected by ocean acidification - not just the groups that make calcium carbonate shells, like those you see on corals, which is what researchers have traditionally assumed," Morris said.
The study suggests ocean acidification has a greater impact on these populations than warming or even reduced nutrient supply. Acidification will most likely cause phytoplankton populations to look very different by the year 2100 than they do today, which could change the entire structure of the marine ecosystem.
"We now know that the structure of phytoplankton populations will morph in the future," Morris said. "Further research will help us determine how that shift will alter other marine life that depend on phytoplankton for survival, and the marine ecosystem in its entirety."
The findings were published in a recent edition of the journal Nature Climate Change.
