SPATIAL VARIABILITY OF NUTRIENT CONCENTRATIONS IN JAMAICA BAY, NY

Jamaica Bay is a highly urbanized area located in New York City by the boroughs of Queens and Brooklyn. Large inputs of the nutrients nitrogen and phosphorus into Jamaica Bay from waste water treatment plants, sewage outflows, and runoff are serious concerns. In an attempt to study the spatial and temporal variation in nutrient concentrations in the area, five pairs of surface water samples during the high tide were collected on July 29, 2009 from the site A, next to Canarsie pier, Brooklyn. Filtered samples were analyzed for dissolved phosphate, silicate, ammonia, nitrate, nitrite within 10 hours by Lachet QuickChem 8500. Temperature, conductivity, pH, ORP, dissolved oxygen (DO) were measured on site by YSI multiparameter probe (600 QS) and ranged from 25.7 to 27.1^oC, 17.3 to 36.9 mS/cm, 8.1 to 8.4, 74.7 to 160.8 mV, and 5.1 to 9.2 mg/l respectively. Although, a separate depth profile indicates that DO can be decreased to 3.2 mg/l at depth of 16 ft from the surface. Limited variation (~ 5%) was observed in concentrations of dissolved Ortho-phosphorus and nitrite with an average concentration of 6.8 ± 0.3 μM and 7.2 ± 0.4 μM respectively. On other hand, concentrations of nitrate-N (11.3 ± 3.1 μM), ammonia-N (37.1 ± 10.1 μM) and silica (2.9 ± 0.5 μM) vary 15-27%. This variation may be regulated by the biological activities in the summer. There is no significant correlation between nitrite/nitrate and ammonia indicating unclear sources of the nitrite in Bay water which requires further investigation.