Seabirds, breeding on remote islets, can play an important ecological role in transferring nutrients to surrounding waters through their feces (guano). The objective of this project is to evaluate the contribution of nutrients from guano (N and P) to the nutrition of different components of the coral ecosystem (plankton, corals, algae, fish) around islets with large seabird colonies and far from any human source. To do this, we will measure the δ15N values of plankton, coral tissues, algae and fish sampled on a gradient of distance from the islets but also their content in C, N and P. In a second step, we will apprehend if the presence of guano leads to a modification of the physiological parameters of the corals, and the diversity of pelagic communities. This project will provide essential information on the as yet unknown role of seabirds in the functioning of coral reefs, and a first assessment of their positive or negative effect on coral physiology.
Seabirds supply nitrogen to reef-building corals on remote Pacific islets