title: Limited phosphorus availability is the Achilles heel of tropical reef corals in a warming ocean.
abstract: During the 20(th) century, seawater temperatures have significantly increased, leading to profound alterations in biogeochemical cycles and ecosystem processes. Elevated temperatures have also caused massive bleaching (symbiont/pigment loss) of autotrophic symbioses, such as in coral-dinoflagellate association. As symbionts provide most nutrients to the host, their expulsion during bleaching induces host starvation. However, with the exception of carbon, the nutritional impact of bleaching on corals is still unknown, due to the poorly understood requirements in inorganic nutrients during stress. We therefore assessed the uptake rates of nitrogen and phosphate by five coral species maintained under normal and thermal stress conditions. Our results showed that nitrogen acquisition rates were significantly reduced during thermal stress, while phosphorus uptake rates were significantly increased in most species, suggesting a key role of this nutrient. Additional experiments showed that during thermal stress, phosphorus was required to maintain symbiont density and photosynthetic rates, as well as to enhance the translocation and retention of carbon within the host tissue. These findings shed new light on the interactions existing between corals and inorganic nutrients during thermal stress, and highlight the importance of phosphorus for symbiont health.
authors.affiliation: Centre Scientifique de Monaco, Marine Department, Principality of Monaco, 8 Quai Antoine Ier, MC-98000, Monaco.
authors.forename: Leïla
authors.initials: L
authors.lastname: Ezzat
authors.affiliation: LEMAR - UMR 6539 UBO/CNRS/IRD, Institut Universitaire Européen de la Mer, Place Nicolas Copernic, 29280 Plouzané, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Maguer
authors.affiliation: Centre Scientifique de Monaco, Marine Department, Principality of Monaco, 8 Quai Antoine Ier, MC-98000, Monaco.
authors.forename: Renaud
authors.initials: R
authors.lastname: Grover
authors.affiliation: Centre Scientifique de Monaco, Marine Department, Principality of Monaco, 8 Quai Antoine Ier, MC-98000, Monaco.
authors.forename: Christine
authors.initials: C
authors.lastname: Ferrier-Pagès
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000254:growth & development*; D057894:Coral Reefs; D057232:Global Warming; D009792:Oceans and Seas; D010758:Phosphorus / Q000378:metabolism*; D014329:Tropical Climate
chemical_list: D010758:Phosphorus