Major Sources of Organic Matter in a Complex Coral Reef Lagoon: Identification from Isotopic Signatures (δ13C and δ15N)

A comprehensive analysis of the Lagoons of New Caledonia reveals that coral reef trophic networks are sustained by a diverse range of organic matter (OM) sources, varying significantly in origin and composition. The study found that δ13C isotopic signatures were more effective than δ15N in identifying these sources, which include mangroves, seagrass beds, rivers, and marine particulate OM. Spatial variations along a coast-to-barrier reef gradient showed that while river-derived OM dominates near the coast, marine-derived OM becomes prevalent on barrier reefs. The relative importance of different OM sources shifts seasonally and spatially, with seagrass, Trichodesmium spp., and macroalgae gaining prominence further from the coast. This research underscores substantial trophic connections between coral reefs and surrounding ecosystems, emphasizing the need for fine-scale environmental assessments to understand broader patterns.

Briand, M. J., Bonnet, X., Goiran, C., Guillou, G., & Letourneur, Y. (2015). Major Sources of Organic Matter in a Complex Coral Reef Lagoon: Identification from Isotopic Signatures (δ13C and δ15N). Plos One, 10(7), e0131555. https://doi.org/10.1371/journal.pone.0131555