Dynamics of nitrogen and phosphorus retention during wetland ecosystem succession

摘要: We compared the mechanisms of nitrogen (N) and phosphorus (P) removal in four young (<15 years old) constructed estuarine marshes with paired mature natural to determine how nutrient retention changes during wetland ecosystem succession. In wetlands, N begins as soon emergent vegetation becomes established soil organic matter starts accumulate, which is usually within first 1–3 years. Accumulation carbon sets stage for denitrification which, after 5–10 years, removes approximately same amount accumulating matter, g/m2/yr each, under conditions low loadings. Under high loadings, stored doubles while from may increase by an order magnitude or more. Both accumulation provide long-term reliable regardless loading rates. Phosphorus removal, on other hand, greatest succession when sediment deposition sorption/precipitation P are greatest. During this time, retain 3 g P/m2/yr loadings much 30 However, sedimentation decreases sorption sites become saturated, levels supported (1–2 P/m2/yr) incoming aqueous particulate Fe, Al Ca. cycling wetlands differs forest terrestrial ecosystems that conservation early succession, not middle late stages. Conservation largely regulated geochemical processes (sorption, precipitation) operate independently contrast, controlled biological (organic accumulation, denitrification) change proceeds.