AB 22:261-279 (2014)  -  DOI: https://doi.org/10.3354/ab00581

ABSTRACT: Since the Industrial Revolution, the partial pressure of carbon dioxide (pCO₂) has been increasing and global ocean surface waters have absorbed 30% of the anthropogenic CO₂ released into the atmosphere. An increase in pCO₂ in surface ocean waters causes an increase in bicarbonate ions (HCO₃^-) and protons (H⁺) and a decrease in carbonate ions (CO₃^2-), thereby decreasing the pH and the saturation state of the seawater with respect to CO₃^2-. These changes in ocean chemistry (termed ocean acidification) are expected to have negative impacts on marine calcifying organisms. Because calcifying marine primary producers are important to the carbon cycle and rocky shore habitat structure and stability, investigating how they will respond to future oceanic pCO₂ levels is a relevant and important topic of research. Due to a recent strong increase in the number of studies investigating the responses of calcifying marine macroalgae to elevated pCO₂, this review aims to present the state of knowledge on the response of calcifying macroalgae to ocean acidification alone and in combination with global and local stressors. We discuss the physiological responses of calcifying macroalgae to elevated pCO₂ within the contexts biogeography, taxonomy, and calcification mechanisms. Generally, coralline algae that deposit high-Mg calcite are most susceptible to high pCO₂, and polar species are particularly at risk. However, some dolomite-depositing species may be able to acclimate to high pCO₂. Calcifiers generally show sensitivity to overgrowth and outcompetition by noncalcifying algae when grown under elevated CO₂ conditions, and this trend could be amplified under conditions of high inorganic nutrients. However, it still remains unknown whether or not calcifiers will be able to adapt to their rapidly changing environments. We discuss the lack of research on this topic, and provide some suggestions for how this knowledge gap can be filled by future research.

KEY WORDS: Ocean acidification · Calcification · Macroalgae · Benthic communities · Eutrophication

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Cite this article as: Hofmann LC, Bischof K (2014) Ocean acidification effects on calcifying macroalgae. Aquat Biol 22:261-279. https://doi.org/10.3354/ab00581 Export citation Share:    Facebook - - linkedIn