Sixty-five years ago, Teal’s (1962) study showed that salt marsh primary production was greater than community respiration. To explain this result, he suggested that marshes exported excess organic matter either directly as organic matter, or as organisms, to coastal waters. This concept, that marshes were “outwelling” material to the adjacent estuary and coastal oceans, was soon expanded to nutrients as well. However, the actual importance of the marsh in supplying organic matter and nutrients to adjacent coastal systems has been controversial and reviews debating the importance of outwelling from marshes have regularly appeared over the decades (Nixon 1980, Childers et al. 2000, Odum 2000, Valiela et al. 2000, Boynton and Nixon 2013). It has also been argued that in some cases the coastal ocean can act as a source of nutrients to the marsh and estuary (“inwelling”).