Dynamic CO 2 and pH levels in coastal, estuarine, and inland waters: Theoretical and observed effects on harmful algal blooms

John A. Raven (Lead / Corresponding author), Christopher S. Gobler (Lead / Corresponding author), Per Juel Hansen

    Research output: Contribution to journalArticle

    7 Citations (Scopus)

    Abstract

    Rising concentrations of atmospheric CO 2 results in higher equilibrium concentrations of dissolved CO 2 in natural waters, with corresponding increases in hydrogen ion and bicarbonate concentrations and decreases in hydroxyl ion and carbonate concentrations. Superimposed on these climate change effects is the dynamic nature of carbon cycling in coastal zones, which can lead to seasonal and diel changes in pH and CO 2 concentrations that can exceed changes expected for open ocean ecosystems by the end of the century. Among harmful algae, i.e. some species and/or strains of Cyanobacteria, Dinophyceae, Prymnesiophyceae, Bacillariophyceae, and Ulvophyceae, the occurrence of a CO 2 concentrating mechanisms (CCMs) is the most frequent mechanism of inorganic carbon acquisition in natural waters in equilibrium with the present atmosphere (400 μmol CO 2 mol −1 total gas), with varying phenotypic modification of the CCM. No data on CCMs are available for Raphidophyceae or the brown tide Pelagophyceae. Several HAB species and/or strains respond to increased CO 2 concentrations with increases in growth rate and/or cellular toxin content, however, others are unaffected. Beyond the effects of altered C concentrations and speciation on HABs, changes in pH in natural waters are likely to have profound effects on algal physiology. This review outlines the implications of changes in inorganic cycling for HABs in coastal zones, and reviews the knowns and unknowns with regard to how HABs can be expected to ocean acidification. We further point to the large regions of uncertainty with regard to this evolving field.

    Original languageEnglish
    Article number101594
    Pages (from-to)1-13
    Number of pages13
    JournalHarmful Algae
    Volume91
    Early online date6 Apr 2019
    DOIs
    Publication statusPublished - Jan 2020

    Keywords

    • Acclimation
    • Adaptation
    • Algal toxins
    • Eutrophication
    • Experimental evolution
    • Global warming
    • Harmful algae
    • Inorganic carbon
    • Ocean acidification

    Fingerprint Dive into the research topics of 'Dynamic CO <sub>2</sub> and pH levels in coastal, estuarine, and inland waters: Theoretical and observed effects on harmful algal blooms'. Together they form a unique fingerprint.

  • Cite this