Seasonal dynamics of iron and phosphorus in reservoir sediments in Eucalyptus plantation region

Abstract Background Iron (Fe) and phosphorus (P) dynamics in sediments have direct indirect impacts on water quality. However, the mobility of P Fe reservoir Eucalyptus plantation region remains unclear. This study examined pollution a using novel planar optode, ZrO-Chelex DGT, DIFS model. Results Direct situ investigations showed that levels labile were smaller species-dominated (X2) compared to without species (X1). The mean concentration decreased by 25% 42% from X1 X2. decrement was insignificant ( p = 0.20) surface sediment for P. significant disparity DGT-Fe (Fe 2+ ) 0.03) observed could be attributed species’ elevated organic matter (tannins) at X2, which reacted consumed Fe. For both regions, maximum occurred November (autumn). reductive decomposition Fe/Mn oxides recognized as main driver their high efflux July November. Low December (winter) due adsorption oxides. synchronizes uniformly with indicating existence coupling relationship r > 0.8, < 0.01) regions. positive diffusion fluxes regions suggested release substantially higher 0.05) summer (anoxic period) than winter (aerobic period), hypoxia redox conditions influenced seasonal From model, replenishment ability reactive during anoxic period R 0.7, k 1 79.4 day − , - 0.2 aerobic 0.4, 14.2 0.1 ), suggesting oxygen inhibited sediments. Conclusion Our results indicated hypoxia, (organic (tannins)), findings provided an insight into -dominated and, moreover, serves reference developing future studies