Biogeochemical patterns among invert-microbe symbioses

Abstract

To date, most studies examining the biogeochemistry of invertebrate symbioses with primary producers have focused on key “lab rat” species. For example, much of our understanding of coral nitrogen metabolism is based on studies of Stylophora pistillata. Relatively fewer works have utilized standardized methods to examine how biogeochemical processes vary across the spectrum of symbiotic associations. Here, we present a global stable isotope dataset from tropical gorgonians, hard corals, and sponges in symbiosis with Symbiodinium and cyanobacteria, respectively. Patterns of autotrophic carbon metabolism are closely linked with productivity, whereas nitrogen metabolism varies markedly among taxa and species. These data suggest that marine symbioses vary along a spectrum from obligate to facultative autotrophy, where symbiont identity and specificity appear to play important roles.