Consumer Nutrient Cycling

Consumer-driven nutrient cycling is now recognized as an essential component of ecosystem functioning in freshwater systems – our lab is one of the first to extend this research framework to marine environments. In collaboration with Jacob Allgeier (University of Washington), we have shown that nearshore waters of The Bahamas are extremely oligotrophic, suggesting that nutrient cycling by marine organisms, namely fishes, may be a major vector of nutrient transport. For instance, seagrass beds have been viewed as a key link in supporting high densities of consumer fauna, but it may be equally plausible that, especially in oligotrophic systems, consumer-driven nutrient recycling is a necessary driver of seagrass productivity.  We are investigating these relationships using a series of artificial reefs constructed in shallow bays in The Bahamas and Haiti. These artificial reefs will serve as one of our core experimental tools in the coming years, allowing for replicated, mechanistic, tests of links between consumer nutrient supply and ecosystem function.

We have extended this line of research to coral reefs by coupling Jake’s empirical estimates of fish excretion rates with large-scale surveys of fish communities across The Bahamas.  These data suggest an exciting link between fish excretion and coral health.  We will be extending these approaches across other data sets collected across the Caribbean, looking to detail specific links between fish community structure and ecosystem processes.