Nutrient cycling in early coral life stages: Pocillopora damicornis larvae provide their algal symbiont (Symbiodinium) with nitrogen acquired from bacterial associates. Issue 8 (18th June 2013)

• Record Type: Journal Article
• Authors: Ceh, Janja; Kilburn, Matt R.; Cliff, John B.; Raina, Jean‐Baptiste; van, Mike; Bourne, David G.
• Is Part Of: Ecology and evolution. Volume 3:Issue 8(2013:Aug.)
• Page Start: 2393
• Page End: 2400
• Publication Date: 2013-06-18
• Subjects: Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.642
• Languages: English
• ISSNs: 2045-7758

Abstract

<abstract abstract-type="main" id="ece3642-abs-0001"> <title>Abstract</title> <p>The waters surrounding coral reef ecosystems are generally poor in nutrients, yet their levels of primary production are comparable with those reported from tropical rain forests. One explanation of this paradox is the efficient cycling of nutrients between the coral host, its endosymbiotic alga <italic>Symbiodinium</italic> and a wide array of microorganisms. Despite their importance for the animals' fitness, the cycling of nutrients in early coral life stages and the initial establishment of partnerships with the microbes involved in these processes has received little scrutiny to date. Nitrogen is an essential but limited nutrient in coral reef ecosystems. In order to assess the early nutrient exchange between bacteria and corals, coral larvae of the species <italic>Pocillopora damicornis</italic> were incubated with two coral‐associated bacteria (<italic>Alteromonas</italic> sp., or <italic>Vibrio alginolyticus), </italic> prelabeled with the stable nitrogen isotope <sup>15</sup>N. The incorporation and translocation of nitrogen from <italic>Vibrio</italic>‐ and <italic>Alteromonas</italic> bacteria into <italic>P. damicornis</italic> coral larvae and specifically into the coral‐symbiotic <italic>Symbiodinium</italic> were detected by nanoscale secondary ion mass spectrometry (NanoSIMS). A significant increase in the amount of enriched <sup>15</sup>N (two to threefold compared to natural abundance) was observed in <italic>P. damicornis</italic> larvae within 8 h of incubation for both bacterial treatments (one‐way ANOVA, <italic> F</italic><sub>5, 53</sub> = 18.03, <italic>P</italic> = 0.004 for <italic>Alteromonas</italic> sp. and <italic>F</italic><sub>5, 53</sub> = 18.03, <italic>P</italic> = 0.0001 for <italic>V. alginolyticus</italic>). These findings reveal that coral larvae acquire nutrients previously taken up from the environment by bacteria. The additional nitrogen may increase the survival rate and fitness of the developing coral and therefore contribute to the successful maintenance of coral reefs.</p> </abstract>