The Coastal Ocean as Source as Well as Sink of Nitrogen to an Estuary

Qizhong Guo, Norbert P. Psuty

Carla G. Pinheiro, Nalini Sankararamakrishnan, and Jeffrey P. Pace

To be presented at the 3^rd International Symposium on Environmental Hydraulics,

Tempe, Arizona, USA, December 5-8, 2001. 

Abstract

Nitrogen flux through an ocean-estuary boundary was continuously-measured and recorded using a current meter and an in situ nutrient analyzer.  The instruments were deployed at Barnegat Inlet, New Jersey, USA from March 17 to April 11, 2000. Measured current velocity, water depth, and nitrate concentration were used to calculate the nitrate flux. The calculated results indicate a net input of nitrate from the coastal ocean to Barnegat Bay during part of the record. Therefore, the flushing model of decreasing nutrient concentration toward the mouths of estuaries may be inappropriate for Barnegat Bay. The results obtained from this study can be used to refine existing nitrogen loading estimates.  The results will also fill critical data gaps in the knowledge required for dynamic water quality modeling of the Bay.

Net Nitrate Flux over Each Tidal Cycle at Barnegat Inlet
(Positive: Import to Bay, Negative: Export to Ocean)