MEPS 664:87-102 (2021)  -  DOI: https://doi.org/10.3354/meps13659

ABSTRACT: The laminarialean kelp Saccharina latissima is a common macroalga along rocky shorelines that is also frequently used in aquaculture. This study examined how ocean acidification may alter the growth of S. latissima as well as grazing on S. latissima by the gastropod Lacuna vincta. Under elevated nutrients, S. latissima experienced significantly enhanced growth at pCO₂ levels ≥1200 µatm compared to ambient pCO₂ (~400 µatm). Elevated pCO₂ (≥830 µatm) also significantly reduced herbivory of L. vincta grazing on S. latissima relative to ambient pCO₂. There was no difference in grazing of S. latissima previously grown under elevated or ambient pCO₂, suggesting lowered herbivory was due to harm to the gastropods rather than alteration of the biochemical composition of the kelp. Decreased herbivory was specifically elicited when L. vincta were exposed to elevated pCO₂ in the absence of food for ≥18 h prior to grazing, with reduced grazing persisting 72 h. Elevated growth of S. latissima and reduced grazing by L. vincta at 1200 µatm pCO₂ combined to increase net growth rates of S. latissima more than 4-fold relative to ambient pCO₂. L. vincta consumed 70% of daily production by S. latissima under ambient pCO₂ but only 38 and 9% at 800 and 1200 µatm, respectively. Collectively, decreased grazing by L. vincta coupled with enhanced growth of S. latissima under elevated pCO₂ demonstrates that increased CO₂ associated with climate change and/or coastal processes will dually benefit commercially and ecologically important kelps by both promoting growth and reducing grazing pressure.

KEY WORDS: Ocean acidification · Kelp · Gastropods · Grazing

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Cite this article as: Young CS, Doall MH, Gobler CJ (2021) Dual benefit of ocean acidification for the laminarialean kelp Saccharina latissima: enhanced growth and reduced herbivory. Mar Ecol Prog Ser 664:87-102. https://doi.org/10.3354/meps13659 Export citation Share:    Facebook - - linkedIn