| Four size fractions of the sediment of six environments of the upper Paraná River floodplain were analyzed for carbon, nitrogen, and phosphorus contents and microbial respiration (oxygen consumption). Particle size did not affect nitrogen and phosphorus content or microbial activity, but did affect carbon content (F = 4.274, df = 3; 20, p = 0.020). The carbon concentration of ultra-fine particles was significantly lower than that of other sizes of sediment particles. Microbial respiration values were well predicted by sediment chemical composition, as shown by multiple regression (microbial respiration = -0.39 - 0.210C + 0.108N + 0.796P; F = 7.0495, p = 0.0022). However, phosphorus was the element which best explained the microbial respiration (partial... |
