Stable isotopes of nitrate (δN and δO) as functional indicators of nitrogen processing in constructed wetlands.

The effectiveness of nitrogen removal in wetlands relies heavily on the biological processes that control its removal. Here, we used δN and δO of nitrate (NO) to assess the presence and the dominance of transformation processes of nitrogen in two urban water treatment wetlands in Victoria, Australia over two rainfall events. Laboratory incubation experiments were undertaken in both light and dark to measure the isotopic fractionation factor of nitrogen assimilation (by periphyton and algae) and benthic denitrification (using bare sediment).

Role of organic carbon, nitrate and ferrous iron on the partitioning between denitrification and DNRA in constructed stormwater urban wetlands.

Denitrification (DNF) and dissimilatory nitrate reduction to ammonium (DNRA) are two competing nitrate reduction pathways that remove or recycle nitrogen, respectively. However, factors controlling the partitioning between these two pathways are manifold and our understanding of these factors is critical for the management of N loads in constructed wetlands. An important factor that controls DNRA in an aquatic ecosystem is the electron donor, commonly organic carbon (OC) or alternatively ferrous iron and sulfide.

Thin ferrihydrite sediment capping sequestrates phosphorus experiencing redox conditions in a shallow temperate lacustrine wetland.

Synthesized ferrihydrite (Fh) with the dosages of 0.3, 0.6 and 0.