title: Extensive phenotypic plasticity of a Red Sea coral over a strong latitudinal temperature gradient suggests limited acclimatization potential to warming.
abstract: Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12° latitudes featuring a steep temperature gradient between the northern (28.5°N, 21-27°C) and southern (16.5°N, 28-33°C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28-29°C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals.
authors.affiliation: Helmholtz Center for Ocean Research (GEOMAR), Wischhofstr. 1-3, 24148 Kiel, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Sawall
authors.affiliation: Faculty of Marine Science, King Abdulaziz University (KAU), P.O. Box 80207, Jeddah 21589, Saudi Arabia.
authors.forename: Abdulmoshin
authors.initials: A
authors.lastname: Al-Sofyani
authors.affiliation: Ecological Modelling, Leibniz Center for Tropical Marine Ecology (ZMT), Fahrenheitstr. 6, 28359 Bremen, Germany.
authors.forename: Sönke
authors.initials: S
authors.lastname: Hohn
authors.affiliation: Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
authors.forename: Eulalia
authors.initials: E
authors.lastname: Banguera-Hinestroza
authors.affiliation: Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
authors.forename: Christian R
authors.initials: CR
authors.lastname: Voolstra
authors.affiliation: Helmholtz Center for Ocean Research (GEOMAR), Wischhofstr. 1-3, 24148 Kiel, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wahl
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000818:Animals; D037421:Anthozoa / Q000254:growth & development*; D002113:Calcification, Physiologic; D057894:Coral Reefs; D057232:Global Warming; D019156:Indian Ocean; D013559:Symbiosis / Q000502:physiology; D013696:Temperature