To evaluate the effect of N. granulata on benthic metabolism and benthic flux of dissolved organic substances (i.e., flux of dissolved substances across the water-sediment interface), and on sedimentary OM quality and bioavailability, we conducted a series of field experiments manipulating bioturbation intensity in a S. altern iflora salt marsh and bare intertidal mudflat (see Fig. 1). Each experiment had three treatments (6 replicates each one): (1) unoccupied burrows (thereafter B treatment); (2) inclusion of adult crabs N. granulata in burrows (thereafter
B+C treatment); and (3) exclusion of crabs and burrows used as control (thereafter NBC). Plastic mesh boxes (0.75 cm mesh opening;0.4 m height, 0.5 m diameter; Fig. 1a and b) with a cover of the same mesh (treatment NBC) or without cover (treatments B and B + C) were used to delimit each experimental unit.