TitleEffects of ocean warming and acidification on the energy budget of an excavating sponge
Publication TypeJournal Article
Year of Publication2014
AuthorsFang JKH, Schonberg CHL, Mello-Athayde MA, Hoegh-Guldberg O, Dove S
Date PublishedApr 2014<br/>2014-06-12
ISBN Number1354-1013, 1354-1013
Accession Number1512331747; 19370544
KeywordsAcidification, ASFA 1: Biological Sciences & Living Resources, Bioerosion, Biomass, carbon, carbon dioxide, Cliona orientalis, Coral reefs, D 04040:Ecosystem and Ecology Studies, Dinoflagellates, Ecology Abstracts, Emissions, ENA 01:Air Pollution, Energy, Energy budget, Environment Abstracts, Erosion, M3 1010:Issues in Sustainable Development, Maintenance, Marine, Marine environment, Marine invertebrates, Models, O 1070:Ecology/Community Studies, Oceanic Abstracts, Oceans, Photosynthesis, Porifera, Potential resources, Pressure, Q1 08463:Habitat community studies, Resource management, Summer, survival, Sustainability, Sustainability Science Abstracts, Symbiodinium, Symbionts, Temperature, Temperature effects
AbstractRecent research efforts have demonstrated increased bioerosion rates under experimentally elevated partial pressures of seawater carbon dioxide (pCO sub(2)) 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 CO sub(2) emission scenarios (temperature + pCO sub(2)) 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 CO sub(2) 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' CO sub(2) 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.