Feedback mechanisms stabilise degraded turf algal systems at a CO2 seep site

• Published in: Communications Biology
• Main Authors: Harvey, Ben P., Allen, Ro, Agostini, Sylvain, Hoffmann, Linn J., Kon, Koetsu, Summerfield, Tina C., Wada, Shigeki, Hall-Spencer, Jason M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: General Agricultural and Biological Sciences; General Biochemistry, Genetics and Molecular Biology; Medicine (miscellaneous); Ocean acidification
• Online Access: http://dx.doi.org/10.1038/s42003-021-01712-2; http://www.nature.com/articles/s42003-021-01712-2.pdf; http://www.nature.com/articles/s42003-021-01712-2

Abstract Human activities are rapidly changing the structure and function of coastal marine ecosystems. Large-scale replacement of kelp forests and coral reefs with turf algal mats is resulting in homogenous habitats that have less ecological and human value. Ocean acidification has strong potential to substantially favour turf algae growth, which led us to examine the mechanisms that stabilise turf algal states. Here we show that ocean acidification promotes turf algae over corals and macroalgae, mediating new habitat conditions that create stabilising feedback loops (altered physicochemical environment and microbial community, and an inhibition of recruitment) capable of locking turf systems in place. Such feedbacks help explain why degraded coastal habitats persist after being initially pushed past the tipping point by global and local anthropogenic stressors. An understanding of the mechanisms that stabilise degraded coastal habitats can be incorporated into adaptive management to better protect the contribution of coastal systems to human wellbeing.