title: Nutritional input from dinoflagellate symbionts in reef-building corals is minimal during planula larval life stage.
abstract: Dispersion of larval offspring is of fundamental ecological importance to sessile marine organisms. Photosymbiotic planulae emitted by many reef-forming corals may travel over large distances before settling to form a new colony. It is not clear whether the metabolic requirements of these planula larvae are met exclusively with lipid and protein reservoirs inherited from the mother colony or when metabolic inputs from their endosymbiotic dinoflagellates become important. Pulse-chase experiments using [(13)C]bicarbonate and [(15)N]nitrate, combined with subcellular structural and isotopic imaging of freshly emitted symbiotic larvae from the coral Pocillopora damicornis, show that metabolic input from the dinoflagellates is minimal in the planulae compared with adult colonies. The larvae are essentially lecithotrophic upon emission, indicating that a marked shift in metabolic interaction between the symbiotic partners takes place later during ontogeny. Understanding the cellular processes that trigger and control this metabolic shift, and how climate change might influence it, is a key challenge in coral biology.
authors.affiliation: Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Kopp
authors.affiliation: Unité MCAM UMR7245, Sorbonne Universités, Muséum National d'Histoire Naturelle, CNRS, 75005 Paris, France.
authors.forename: Isabelle
authors.identifier: 0000-0001-9501-746X
authors.initials: I
authors.lastname: Domart-Coulon
authors.affiliation: Aquarium d'Océanopolis, 29210 Brest, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Barthelemy
authors.affiliation: Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.; Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Anders
authors.initials: A
authors.lastname: Meibom
mesh_terms: D000818:Animals; D037421:Anthozoa; D057894:Coral Reefs; D004141:Dinoflagellida / Q000145:classification / Q000235:genetics; D007814:Larva; D008386:Marine Biology; D009747:Nutritional Physiological Phenomena; D010788:Photosynthesis; D013559:Symbiosis
keywords: Coral; NanoSIMS; TEM; larvae; marine ecology; metabolism; photosynthesis; stable isotopes; symbiosis