Assimilation and short‐term processing of microphytobenthos nitrogen in intertidal sediments

Microphytobenthos (MPB) are an important nitrogen (N) sink in coastal systems, but little is known about the fate of N assimilated by MPB. We used an in situ 15 N pulse‐chase experiment in intertidal, nonpermeable, sandy mud to trace the assimilation, transformation, and loss from the sediment of MPB‐N over 31 d. Following assimilation, 15 N was tightly retained in surface sediments, with only up to 8.1% transported to 2–10 cm sediments over 31...