After 2 months of having the experiment running (i.e., 2 months after treatment B was achieved), in situ measurements of benthic metabolism and benthic flux were done by installing a flexible benthic chamber at each experimental plot. Chambers were constructed according to and following the modification . Briefly, a flexible transparent PVC film (10 cm in height) was mounted on the top of a PVC tube (16 cm in diameter, 12 cm in height). The lid (mounted on a PVC ring of 16 cm in diameter and 1.5 cm in height) was attached to the top of the flexible film (see bottom panels in Fig. 1). The lid had two small septa that allowed to sample water inside the chambers using syringes, and also to take direct measurements with needle sensors. Chambers (n = 18, for each mudflat or salt marsh zone) were inserted ~12 cm into the sediment during flooding tide such that 10 cm of the chamber was above the sediment surface.