Ipswich River Nutrient Dynamics: Preliminary Assessment of a Simple Nitrogen-Processing Model.

‘Ihe Ipswich River is a low-gradient, coastal river in northeastem Massachusetts. It is about 55 km long and drains an area of 401 km’. Previous observations and studies indicate high levels of dissolved inorganic nitrogen (DIN) in the headwaters of the river due to urban and residential land use (1). However, concentrations drop quickly with distance downstream, presumably due to biological processing of the nitrogen. A mass balance budget of nitrogen indicates a large unknown nitrogen sink in the Ipswich River (1). To further investigate the dynamics of N cycling in the