Long periods of light can lead to higher local pH
During long summer days, kelp forests in high-latitude waters could create little safe zones for sea creatures in acidifying oceans, new research shows.
Sunlight stretching on for most or all of a day keeps kelps and other big algae working overtime, trapping solar energy through photosynthesis. In the Arctic, kelps pulled enough carbon dioxide from the surrounding seawater to nudge the local pH upward, monitoring showed. Seawater is generally alkaline instead of acidic, but in midsummer, kelp patches pushed the pH average even farther above acidity. In 10 days, average pH in an Arctic kelp patch in Greenland rose from 8.09 to 8.24, an international team of researchers reports December 14 in Science Advances. Follow-up lab tests of kelps suggest that 21 hours or more of sunlight per day should produce that refuge effect.