The Role of Litter in Nutrient Cycling in a Brackish Tidal Marsh

The role of litter in nutrient cycling in a Typha angustifolia dominated brackish tidal marsh was studied with a field experiment. In replicated plots, litter was either removed, replaced with plastic strips (pseudolitter), increased threefold, or left unaltered. One set of plots received fortnightly surface applications of ammonium phosphate solution at an annual rate of 65 g/m2 of N and 72 g/m2 of P. The nutrient additions increased the concentration of dissolved and extractable ammonium and phosphate, but decreased the concentration of dissolved nitrate plus nitrite in the sediment. The effects of the litter manipulations were mostly attributable to the physical structure of the litter layer rather than the decomposition process. Plots with no litter or pseudolitter developed higher concentrations of total NH4 in the sediment than other plots. Also, when litter and pseudolitter were absent, the nutrient additions caused greater increases in PO4 in the sediment. We measured decomposition and changes in ...