Sedimentation of phosphorus fractions and temporal variation in the C:P ratio in La Concepción reservoir, southern Spain

Abstract The settling flux and content of organic carbon (C), organic matter, and different phosphorus (P) fractions were measured fortnightly during a 6‐month stratified period (from early April to early November) with sediment traps located at five different depths in La Concepcion, a mesotrophic and P‐limited reservoir in southern Spain. Characterisation of P fractions in the collected material was performed by a sequential extraction procedure. Sedimentation rates exhibited a distinct seasonal pattern, that allowed us to differentiate three periods: (1) a biogenic sedimentation period (BS), in which the sedimentation rates and total suspended matter concentration were lowest and the result of material of autochthonous origin; (2) a calcium carbonate precipitation period (CCP), in which there were high calcium concentrations in the settling seston; and (3) a rainfall period (R), in which the highest sedimentation rates occurred. Organic C, organic matter, and organic P content were highest in the settl...