The distribution of urea in coastal and oceanic waters: Limnology and Oceangraphy

The distribution of urea has been determined for certain coastal and oceanic waters. The presence of urea-nitrogen in surface waters off the continental shelf between Panama and Callao, Peru, was extremely patchy and varied in concentration from 0.54-5.00 pg-atom urea-N/liter. The higher values were generally from samples collected within a foam slick or windrow. Surface waters in nonupwelling waters north of Callao, Peru, averaged 1.83,ug-atom urea-N/liter while surface waters in upwelling waters south of Callao aver-aged 3.46. Along the continental shelf of the northeast United States between Cape Cod and Cape May, the concentration of urea ranged from 0.25,ug-atom urea-N/liter on the l,OOO-fathom ( 1,830 m) line to a high of 11.20 within New York Harbor. The vertical distribution of urea in Peruvian waters, waters along the northeast United States, as well as Sargasso Sea waters showed considerable fluctuations with depth but there were indi-cations of peaks. The data support the suggestion that urea may serve as an available source of nitrogen for phytoplankton growth