Arctic kelp forests may provide safety from acidifying oceans during long summer days because of extended sunlight exposure.
Long periods of sunlight force big algae, like kelp, to trap more solar energy and absorb more carbon dioxide from the water through photosynthesis. This pushes pH levels upward and provides sea creatures with a less acidic environment.
According to an article in Science Advances, an international team of researchers observed an Arctic kelp patch in Greenland and discovered that the average pH rose from 8.09 to 8.24 in 10 days.
While sea levels are usually alkaline, rising carbon dioxide levels in the atmosphere have contributed not only to rising atmospheric temperatures, but also to falling pH levels and rising acidity in ocean surface water due to chemical reactions when carbon dioxide dissolves in seawater.
Dorte Krause-Jensen of Aarhus University in Denmark, a co-author of the study conducted in Greenland, notes that pH levels have dropped since the industrial revolution.
The shift in pH makes it difficult for organisms like snails and crabs to draw calcium-building materials out of seawater and summer time is a critical period for growth and development. Having a kelp forest or other algae cluster as a refuge provides sea creatures with a more regulated and alkaline environment.
Studies conducted on coastal clusters and their effects on water acidity are relatively new, said Krause-Jensen. Most previous studies have focused on the consequences of acidification in the open ocean.
Krause-Jensen and colleagues monitored acidity in Greenland’s Disko Bay where the sun does not set between May 25 and July 17. While the pH fluctuated, the averages rose during this time, as compared to later in the year and farther south where pH averages remained at 8.1 after 15 ours of sunlight a day.
The assertion that kelp may provide refuge from acidification is being heavily discussed among experts. But overall, tests have confirmed that kelps and algae can contribute to local trends and have an impact on their own local environment.
Image: Tom Thai, CC-BY
Lauren Leising is a freelance writer based out of Athens, Georgia.