Data from: Dynamics of phosphorus pools in drainage ditch sediments within an agricultural catchment

Hydrological dynamics in drainage ditch sediments may impact phosphorus
(P) retention and its potential (re-)release to connected waters. We aimed
at understanding the fate of P in drainage-ditch sediments under dynamic
environmental conditions (i.e., drying-rewetting cycles) by examining P
pool transformations through an isotopic labelling and incubation
experiment. Fresh sediment samples of a drainage ditch were labeled with
18O-enriched inorganic P (Pi), followed by a twenty-four-week incubation
under different environmental conditions. A five-step sequential
extraction scheme was combined with δ18O analysis of Pi (δ18O Pi) to
follow changes in the operationally defined P pools. Few P pools showed
significant changes, but time-resolved results revealed a dynamic
interplay between redox conditions, microbial activity, and P dynamics. A
subsequent decline in microbial P concentrations suggested cell death and
reduced microbial activity, likely caused by hydrological stress. The
δ18OPi values in surface-adsorbed pools retained traces of the original Pi
label after twenty-four weeks, allowing tracking of long-term P
transformations and distinguishing biological and geochemical reactions.