Allometric scaling of estuarine ecosystem metabolism

Significance Coastal margins host some of the most productive habitats on the planet, yet there is still significant uncertainty about the magnitude of carbon fluxes across the land/ocean interface. Scaling up in situ measurements into whole-ecosystem estimates of how these habitats contribute to global biogeochemical cycling has been hindered by their apparent heterogeneity, complex circulation, and sizes that range from tens of meters to hundreds of kilometers. Here, I show that estuarine ecosystem metabolism varies predictably with ecosystem size. The significance of this study is not simply that larger estuaries have lower specific ecosystem metabolism than smaller estuaries, but that this size scaling arises because the residence time of limiting nutrients does not scale isometrically with estuary size.