Near-future ocean warming and acidification alter foraging behaviour, locomotion, and metabolic rate in a keystone marine mollusc

Rael Horwitz, Tommy Norin, Sue Ann Watson, Jennifer C.A. Pistevos, Ricardo Beldade, Simon Hacquart, Jean Pierre Gattuso, Riccardo Rodolfo-Metalpa, Jeremie Vidal-Dupiol, Shaun S. Killen, Suzanne C. Mills

Research output: Contribution to journalArticlepeer-review


Environmentally-induced changes in fitness are mediated by direct effects on physiology and behaviour, which are tightly linked. We investigated how predicted ocean warming (OW) and acidification (OA) affect key ecological behaviours (locomotion speed and foraging success) and metabolic rate of a keystone marine mollusc, the sea hare Stylocheilus striatus, a specialist grazer of the toxic cyanobacterium Lyngbya majuscula. We acclimated sea hares to OW and/or OA across three developmental stages (metamorphic, juvenile, and adult) or as adults only, and compare these to sea hares maintained under current-day conditions. Generally, locomotion speed and time to locate food were reduced ~1.5- to 2-fold when the stressors (OW or OA) were experienced in isolation, but reduced ~3-fold when combined. Decision-making was also severely altered, with correct foraging choice nearly 40% lower under combined stressors. Metabolic rate appeared to acclimate to the stressors in isolation, but was significantly elevated under combined stressors. Overall, sea hares that developed under OW and/or OA exhibited a less severe impact, indicating beneficial phenotypic plasticity. Reduced foraging success coupled with increased metabolic demands may impact fitness in this species and highlight potentially large ecological consequences under unabated OW and OA, namely in regulating toxic cyanobacteria blooms on coral reefs.

Original languageEnglish
Article number5461
JournalScientific Reports
Issue number1
StatePublished - 25 Mar 2020
Externally publishedYes

Bibliographical note

Funding Information:
Financial support was provided by LabEx “CORAIL” (ACCLIMACID to R.H. and S.C.M.), the TOTAL Foundation (ICATEC to S.C.M.), the Ministry for an Ecological and Solidary transition (MTES) and the Foundation for Research on Biodiversity (FRB) under their Ocean Acidification program (ECOSYSTEME to S.C.M.), and Contrat de Projets Etat - Polynésie Française to S.C.M. T.N. was funded by the Danish Council for Independent Research (Individual Postdoctoral Grant and Sapere Aude: DFF-Research Talent Grant; DFF-4181– 00297). S.S.K. was supported by a NERC Advanced Fellowship NE/J019100/1 and a European Research Council Starting Grant 640004. S.-A.W. was funded by an IRCP-SNH-SPDD grant. The authors would like to thank Pascal Ung and Franck Lerouvreur, as well as Yannick Chancerelle, Benoit Espiau, Christine Sidobre, Gilles Siu, Vetea Liao, and Nathalie Tolou. We thank Noa Horwitz for help in the field and laboratory, as well as Dr. Steeve Comeau for providing advice and chemicals. This is a contribution to the STORISK project (ANR-15-CE03-0003-08). The authors declare no conflict of interests.

Publisher Copyright:
© 2020, The Author(s).

ASJC Scopus subject areas

  • General


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