The unique and vulnerable ecosystem of floodplains, characterized by the flood-pulse concept (Junk et al. 1989), are put under pressure as a consequence of human activities. While temperate, boreal and subarctic floodplains were intensively studied, analogy among tropical and sub-tropical floodplains influenced by artificially altered discharge regimes due to hydropower production is rarely available. This study investigates the difference between a human-impacted and a pristine floodplain in subtropical Zambia with focus on particulate phosphorus extracted after Ruttenberg (1992) modified by Slomp (1996). Both floodplains are considered nutrient-poor and phosphorus limited which is why the redox-sensitive, ironbound phosphorus might a relevant species as potential phosphate source during inundation. As a consequence of the upstream reservoir, particulate phosphorus loads including ironbound phosphorus, are reduced (Kunz et al. 2011) and are deficient in the subsequent, impacted floodplain. Additionally, organic-bound phosphorus is of refractory, terrestrial origin in the pristine floodplain while the human-impacted floodplain has a more aquatic and phytoplankton derived signal. Since floodplains are adapted to seasonal floodings, floodplain management of dam-impacted systems is essential in order to provide sufficient nutrients for the surrounding vegetation and agricultural soils to sustain food supply and income for the rural population. To better understand the role and interactions of the different phosphorus species, further research in subtropical regions is required.