03074nas a2200325   4500008004100000020001400041245009200055210006900147260004600216300001400262490000700276520205900283653001802342653001502360653001902375653000902394653001102403653000902414653002202423653001902445653001102464653001202475653001602487100002302503700003302526700003102559700002402590700001702614856011702631       2014                        eng d  a1354-101300aEffects of ocean warming and acidification on the energy budget of an excavating sponge0 aEffects of ocean warming and acidification on the energy budget   aEnglandbWiley Subscription Services, Inc  a1043-10540 v203 aRecent research efforts have demonstrated increased bioerosion rates under experimentally elevated partial pressures of seawater carbon dioxide (pCO2 ) with or without increased temperatures, which may lead to net erosion on coral reefs in the future. However, this conclusion clearly depends on the ability of the investigated bioeroding organisms to survive and grow in the warmer and more acidic future environments, which remains unexplored. The excavating sponge Cliona orientalis Thiele, is a widely distributed bioeroding organism and symbiotic with dinoflagellates of the genus Symbiodinium. Using C. orientalis, an energy budget model was developed to calculate amounts of carbon directed into metabolic maintenance and growth. This model was tested under a range of CO2 emission scenarios (temperature + pCO2 ) appropriate to an Austral early summer. Under a pre-industrial scenario, present day (control) scenario, or B1 future scenario (associated with reducing the rate of CO2 emissions over the next few decades), C. orientalis maintained a positive energy budget, where metabolic demand was likely satisfied by autotrophic carbon provided by Symbiodinium and heterotrophic carbon via filter-feeding, suggesting sustainability. Under B1, C. orientalis likely benefited by a greater supply of photosynthetic products from its symbionts, which increased by up to 56% per unit area, and displayed an improved condition with up to 52% increased surplus carbon available for growth. Under an A1FI future scenario (associated with 'business-as-usual' CO2 emissions) bleached C. orientalis experienced the highest metabolic demand, but carbon acquired was insufficient to maintain the sponge, as indicated by a negative energy budget. These metabolic considerations suggest that previous observations of increased bioerosion under A1FI by C. orientalis may not last through the height of future A1FI summers, and survival of individual sponges may be dependent on the energy reserves (biomass) they have accumulated through the rest of the year.10aAcidification10abioerosion10acarbon balance10aCHAR10aCorals10aCZAR10aEnergy efficiency10aGlobal warming10aOceans10aSponges10atemperature1 aFang, James, K. H.1 aSchönberg, Christine, H. L.1 aMello-Athayde, Matheus, A.1 aHoegh-Guldberg, Ove1 aDove, Sophie  uhttps://reefichno.myspecies.info/content/effects-ocean-warming-and-acidification-energy-budget-excavating-sponge