Acidification counteracts negative effects of warming on diatom silicification

• Main Authors: Coello-Camba, Alexandra, Agustí, Susana
• Format: Text
• Language: English
• Published: 2018
• Subjects: Arctic; Arctic Ocean; Climate change; Ocean acidification
• Online Access: https://doi.org/10.5194/bg-2016-424; https://www.biogeosciences-discuss.net/bg-2016-424/

Diatoms are a significant group contributing up to 40 % of annual primary production in the oceans. They have a special siliceous cell wall that, acting as a ballast, plays a key role in the sequestration of global carbon and silica. Diatoms dominate primary production in the Arctic Ocean, where global climate change is causing increases in water temperature and in the partial pressure of CO 2 ( p CO 2 ). Here we show that as water temperature increases diatoms become stressed, grow to smaller sizes, and decrease their silicification rates. But at higher p CO 2 , as the pH of seawater decreases, silica incorporation rates are increased. In a future warmer Arctic ocean diatoms may have a competitive advantage under increased ocean acidification, as increased p CO 2 counteracts the adverse effects of increasing temperature on silicification and buffers its consequences in the biogeochemical cycles of carbon and silica.