Atmospheric nitrogen deposition to the New Jersey coastal waters and its implications

In situ measurements of atmospheric NO(3)(-) and NH(4)(+) at Sandy Hook on the northern New Jersey (USA) coast and at Tuckerton on the southern New Jersey coast reveal significant temporal and spatial variations of these inorganic N constituents. The mean concentration of NO(3)(-) in precipitation was higher at Sandy Hook (44.6 mu mol/L) than at Tuckerton (29.1 mu mol/L). The mean concentration of NH(4)(+) in precipitation exhibited a similar pattern, being higher at Sandy Hook (26.3 mu mol/L) than at Tuckerton (18.3 mu mol/L). Aerosol NO(3)(-) and NH(4)(+) concentrations at Sandy Hook were also higher than those at Tuckerton. On an annual basis, the total atmospheric deposition of NO(3)(-) was estimated to be 51.1 mmol.m(-2).yr(-1) at Sandy Hook and 32.9 mmol.m(-2).yr(-1) at Tuckerton. For NH(4)(+), the total atmospheric deposition was 32.8 mmol.m(-2).yr(-1) at Sandy Hook and 20.3 mmol.m(-2).yr(-1) at Tuckerton. Wet deposition accounted for up to 89% of the total NO(3)(-) deposition and 76-91% of the total NH(4)(+) deposition on the New Jersey coast. By comparison, NO(3)(-) and NH(4)(+) concentrations are relatively low in estuarine waters of New Jersey. The annual mean NO(3)(-) concentrations recorded in surface waters of the Mullica River-Great Bay Estuary near the Tuckerton atmospheric site during the 2002-2004 period were as follows: 12.1 mu mol/L for the upper estuary, 4.5 mu mol/L for the mid-estuary, 2.5 mu mol/L for the lower estuary, and 1.2 mu mol/L for the bay inlet area. The annual mean NH(4)(+) concentrations in these waters were as follows: 1.5 mu mol/L for the upper estuary, 3.8 mu mol/L for the mid-estuary, 3.8 mu mol/L for the lower estuary, and 2.4 mu mol/L for the bay inlet area. In the Barnegat Bay-Little Egg Harbor Estuary, the mean concentrations of NO(3)(-) plus NO(2)(-) were < 4 mu mol/L. In this system, atmospheric deposition accounts for similar to 39% of the total N load. These results suggest that atmospheric deposition appears to be an important pathway of new N inputs to New Jersey coastal waters and a potentially significant N enrichment source for biotic production.