title: Acclimatization to high-variance habitats does not enhance physiological tolerance of two key Caribbean corals to future temperature and pH.
abstract: Corals are acclimatized to populate dynamic habitats that neighbour coral reefs. Habitats such as seagrass beds exhibit broad diel changes in temperature and pH that routinely expose corals to conditions predicted for reefs over the next 50-100 years. However, whether such acclimatization effectively enhances physiological tolerance to, and hence provides refuge against, future climate scenarios remains unknown. Also, whether corals living in low-variance habitats can tolerate present-day high-variance conditions remains untested. We experimentally examined how pH and temperature predicted for the year 2100 affects the growth and physiology of two dominant Caribbean corals (Acropora palmata and Porites astreoides) native to habitats with intrinsically low (outer-reef terrace, LV) and/or high (neighbouring seagrass, HV) environmental variance. Under present-day temperature and pH, growth and metabolic rates (calcification, respiration and photosynthesis) were unchanged for HV versus LV populations. Superimposing future climate scenarios onto the HV and LV conditions did not result in any enhanced tolerance to colonies native to HV. Calcification rates were always lower for elevated temperature and/or reduced pH. Together, these results suggest that seagrass habitats may not serve as refugia against climate change if the magnitude of future temperature and pH changes is equivalent to neighbouring reef habitats.
authors.affiliation: Coral Reef Research Unit, School of Biological Sciences, University of Essex, Colchester CO4 3SQ, UK Climate Change Cluster (C3), University of Technology Sydney, PO Box 123, Broadway, New South Wales 2007, Australia emma.camp@uts.edu.au.
authors.forename: Emma F
authors.identifier: 0000-0003-1962-1336
authors.initials: EF
authors.lastname: Camp
authors.affiliation: Coral Reef Research Unit, School of Biological Sciences, University of Essex, Colchester CO4 3SQ, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Smith
authors.affiliation: Climate Change Cluster (C3), University of Technology Sydney, PO Box 123, Broadway, New South Wales 2007, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Evenhuis
authors.affiliation: Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA Atlantic Oceanographic and Meteorological Laboratory (AOML), NOAA, 4301 Rickenbacker Causeway, Miami, FL 33149, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Enochs
authors.affiliation: Atlantic Oceanographic and Meteorological Laboratory (AOML), NOAA, 4301 Rickenbacker Causeway, Miami, FL 33149, USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Manzello
authors.affiliation: School of Mathematical and Physical Sciences, University of Technology Sydney, PO Box 123, Broadway, New South Wales 2007, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Woodcock
authors.affiliation: Climate Change Cluster (C3), University of Technology Sydney, PO Box 123, Broadway, New South Wales 2007, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Suggett
mesh_terms: D000064:Acclimatization; D000818:Animals; D037421:Anthozoa / Q000502:physiology*; D017691:Caribbean Region; D017753:Ecosystem; D006863:Hydrogen-Ion Concentration; D013045:Species Specificity; D013696:Temperature; D014900:West Indies
keywords: climate change; coral reefs; environmental variance; ocean acidification; seagrass beds; thermal stress