Nutrient dynamics in the floodplain ponds of the Paraná River (Argentina) dominated by the water hyacinth Eichhornia crassipes.

摘要: Some aspects of nutrient status and dynamics prevailing during low high water conditions in the fringing floodplain ponds Parana River dominated by floating macrophyte Eichhornia crassipes are described. During summertime conditions, DIN:DRP ratios (0.16–1.0) DIN (0.5–4.8 μmol.liter−1) root-zone meadows suggest that growth is limited nitrogen. DRP concentrations appear to be controlled more abiotic sorption-dissolution than biological reactions. Preflood fluxes from sediments, as estimated porewater profiles, show a minimum 1.19 0.38 mmol.m−2.d−1 were regenerated respectively. Heterotrophic N2 fixation primarily associated with decaying litter (0.4 3.2 μmolN2.g−1.d−1). Nutrient recycling sediments meadow-litter, heterotrophic (1.4 mmolN.m−2.d−1) sufficient sustain productivity for long periods time, without invoking large inputs river. The early isolation characterized very dynamic behavior DIN, reflecting marked imbalances between N supply demand biota. After hydrologic ponds, rapidly decreases undetectable levels stays following 3 weeks, presumably result phytoplankton sediment bacteria. increases again values 3–8 weeks after flood, re-establishment NH4 + sediments. Compared remain relatively change little flood. Because their small amplitude short duration, floods do not stimulate production Parana.