Sensitivity of sea urchin fertilization to pH varies across a natural pH mosaic

• Published in: Ecology and Evolution
• Main Authors: Kapsenberg, Lydia, E, Okamoto, Daniel, E, Dutton, Jessica M., Hofmann, Gretchen E.
• Other Authors: UCSB (UCSB), University of California Santa Barbara (UC Santa Barbara), University of California (UC)-University of California (UC), Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Simon Fraser University = Université Simon Fraser (SFU.ca), University of California Los Angeles (UCLA), University of California (UC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: [SDE]Environmental Sciences; Ocean acidification
• Online Access: https://hal.sorbonne-universite.fr/hal-01468076; https://hal.sorbonne-universite.fr/hal-01468076/document; https://hal.sorbonne-universite.fr/hal-01468076/file/ece32776.pdf; https://doi.org/10.1002/ece3.2776

International audience In the coastal ocean, temporal fluctuations in pH vary dramatically across biogeo-graphic ranges. How such spatial differences in pH variability regimes might shape ocean acidification resistance in marine species remains unknown. We assessed the pH sensitivity of the sea urchin Strongylocentrotus purpuratus in the context of ocean pH variability. Using unique male–female pairs, originating from three sites with similar mean pH but different variability and frequency of low pH (pH T ≤ 7.8) exposures, fertilization was tested across a range of pH (pH T 7.61–8.03) and sperm concentrations. High fertilization success was maintained at low pH via a slight right shift in the fertilization function across sperm concentration. This pH effect differed by site. Urchins from the site with the narrowest pH variability regime exhibited the greatest pH sensitivity. At this site, mechanistic fertilization dynamics models support a decrease in sperm–egg interaction rate with decreasing pH. The site differences in pH sensitivity build upon recent evidence of local pH adaptation in S. purpuratus and highlight the need to incorporate environmental variability in the study of global change biology.