University Of Tasmania

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High CO2 enhances the competitive strength of seaweeds over corals

journal contribution
posted on 2023-05-19, 08:16 authored by Diaz-Pulido, G, Gouezo, M, Tilbrook, BD, Dove, S, Anthony, KRN
Space competition between corals and seaweeds is an important ecological process underlying coral-reef dynamics. Processes promoting seaweed growth and survival, such as herbivore overfishing and eutrophication, can lead to local reef degradation. Here, we present the case that increasing concentrations of atmospheric CO2 may be an additional process driving a shift from corals to seaweeds on reefs. Coral (Acropora intermedia) mortality in contact with a common coral-reef seaweed (Lobophora papenfussii) increased two- to threefold between background CO2 (400ppm) and highest level projected for late 21st century (1140ppm). The strong interaction between CO2 and seaweeds on coral mortality was most likely attributable to a chemical competitive mechanism, as control corals with algal mimics showed no mortality. Our results suggest that coral (Acropora) reefs may become increasingly susceptible to seaweed proliferation under ocean acidification, and processes regulating algal abundance (e.g. herbivory) will play an increasingly important role in maintaining coral abundance.


Publication title

Ecology Letters








Institute for Marine and Antarctic Studies


Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

Copyright 2010 Blackwell Publishing Ltd/CNRS

Repository Status

  • Restricted

Socio-economic Objectives

Marine biodiversity