Simplification of marine ecosystems under ocean acidification (text & video)

OA Week 2021, Northeast Atlantic Hub Session

Dr. Ben Harvey, Shimoda Marine Research Center, University of Tsukuba, Japan


Human activities are rapidly changing the structure of coastal marine ecosystems, but the ecological consequences of these changes remain uncertain. Natural analogues of futuristic conditions are increasingly being used to assess the likely effects of rising atmospheric CO2 emissions on marine ecosystems. Here, using a CO2 seep in Japan, we show how ocean acidification causes habitat and biodiversity loss, resulting in the simplification of marine ecosystems. This simplification involves structurally complex habitat-forming species (including corals and larger macrophytes) being replaced by more homogenous and simple turf algal habitats. Such ecological shifts are concerning because they result in habitats that have less ecological and human value. Moreover, once these ecological shifts occur, OA-driven stabilising feedback loops ‘lock-in’ these novel turf systems making them particularly difficult to reverse. By understanding the ecological processes responsible for driving community shifts, we can better assess how communities and ecosystems are likely to be altered by ocean acidification. Taken together, we demonstrate how the simplification of marine habitats by increased CO2 levels will cascade through the ecosystem and will have severe consequences for the provision of goods and services.

Ocean Acidification Week 2021 was sponsored by the following organizations:

(1) GOA-ON, the Global Ocean Acidification Observing Network,

(2) NOAA, the United States National Oceanic & Atmospheric Administration,

(3) IAEA OA-ICC, the International Atomic Energy Agency – Ocean Acidification International Coordination Centre, and

(4) IOC-UNESCO – the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization

For more information, please visit

GOA-ON, YouTube, 24 September 2021. Text and video.

  • Reset


OA-ICC Highlights

%d bloggers like this: