title: Ocean acidification alters the response of intertidal snails to a key sea star predator.
abstract: Organism-level effects of ocean acidification (OA) are well recognized. Less understood are OA's consequences for ecological species interactions. Here, we examine a behaviourally mediated predator-prey interaction within the rocky intertidal zone of the temperate eastern Pacific Ocean, using it as a model system to explore OA's capacity to impair invertebrate anti-predator behaviours more broadly. Our system involves the iconic sea star predator, Pisaster ochraceus, that elicits flee responses in numerous gastropod prey. We examine, in particular, the capacity for OA-associated reductions in pH to alter flight behaviours of the black turban snail, Tegula funebralis, an often-abundant and well-studied grazer in the system. We assess interactions between these species at 16 discrete levels of pH, quantifying the full functional response of Tegula under present and near-future OA conditions. Results demonstrate the disruption of snail anti-predator behaviours at low pH, with decreases in the time individuals spend in refuge locations. We also show that fluctuations in pH, including those typical of rock pools inhabited by snails, do not materially change outcomes, implying little capacity for episodically benign pH conditions to aid behavioural recovery. Together, these findings suggest a strong potential for OA to induce cascading community-level shifts within this long-studied ecosystem.
authors.affiliation: Bodega Marine Laboratory, 2099 Westshore Road, Bodega Bay, CA 94923, USA bmjellison@ucdavis.edu.
authors.forename: Brittany M
authors.initials: BM
authors.lastname: Jellison
authors.affiliation: Bodega Marine Laboratory, 2099 Westshore Road, Bodega Bay, CA 94923, USA.
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Ninokawa
authors.affiliation: Bodega Marine Laboratory, 2099 Westshore Road, Bodega Bay, CA 94923, USA Department of Earth and Planetary Sciences, University of California at Davis, Davis, CA 95616, USA.
authors.forename: Tessa M
authors.initials: TM
authors.lastname: Hill
authors.affiliation: Bodega Marine Laboratory, 2099 Westshore Road, Bodega Bay, CA 94923, USA Department of Evolution and Ecology, University of California at Davis, Davis, CA 95616, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Sanford
authors.affiliation: Bodega Marine Laboratory, 2099 Westshore Road, Bodega Bay, CA 94923, USA Department of Evolution and Ecology, University of California at Davis, Davis, CA 95616, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Gaylord
mesh_terms: D000818:Animals; D006863:Hydrogen-Ion Concentration; D010140:Pacific Ocean; D011235:Predatory Behavior; D012623:Seawater / Q000737:chemistry*; D012908:Snails / Q000502:physiology*; D013215:Starfish
keywords: avoidance behaviour; elevated carbon dioxide; global climate change; marine stressors; predator–prey; tidepool