Nutrient cycling in early coral life stages: Pocillopora damicornis larvae provide their algal symbiont (Symbiodinium) with nitrogen acquired from bacterial associates
Article first published online: 18 JUN 2013
© 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
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Ecology and Evolution
Volume 3, Issue 8, pages 2393–2400, August 2013
How to Cite
Ecology and Evolution 2013; 3(8): 2393–2400
- Issue published online: 12 AUG 2013
- Article first published online: 18 JUN 2013
- Manuscript Accepted: 19 MAY 2013
- Manuscript Revised: 16 MAY 2013
- Manuscript Received: 19 MAR 2013
- Australian Microscopy & Microanalysis Research Facility
- Western Australian Marine Science Institution
- Australian Institute of Marine Science
- coral larvae;
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 Symbiodinium 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 Pocillopora damicornis were incubated with two coral-associated bacteria (Alteromonas sp., or Vibrio alginolyticus), prelabeled with the stable nitrogen isotope 15N. The incorporation and translocation of nitrogen from Vibrio- and Alteromonas bacteria into P. damicornis coral larvae and specifically into the coral-symbiotic Symbiodinium were detected by nanoscale secondary ion mass spectrometry (NanoSIMS). A significant increase in the amount of enriched 15N (two to threefold compared to natural abundance) was observed in P. damicornis larvae within 8 h of incubation for both bacterial treatments (one-way ANOVA, F5,53 = 18.03, P = 0.004 for Alteromonas sp. and F5,53 = 18.03, P = 0.0001 for V. alginolyticus). 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.