Nitrogen-15 Uptake, F-ratio, Ammonium Concentration, and Low-level Nitrate Concentration Measured during the U.S. JGOFS Arabian Sea Process Study

Depth profiles of nitrogen-15 uptake rates are available for nitrite (NO2) labeled substrate, nitrate (NO3) labeled substrate, and ammonium (NH4) labeled substrate. N-15 uptake rate units are in nMol N /kg/h. Areal summary data reflect corrections to the profile data and a reassessment of the diel cycle for nitrogen uptake.

The profile data are integrated (1% Io) daily to create the areal summary. Units for nitrogen-15 uptake areal summaries are in mMol N /m^2/day. F-ratio data are calculated as follows: pNO3/(pNO2+pNO3+NH4), where p is the N-15 uptake rate from the indicated substrate.

Depth profiles of ammonium concentration are also available. These are high sensitivity data of ammonium in the euphotic zone, with a detection limit of 0.002 micro molar. Depth profiles of low-level (nanomolar range) nitrate concentrations are also available.

The data is public domain and can be retrieved on-line at "usjgofs.whoi.edu/jg/dir/jgofs/" [This information was obtained from U.S. JGOFS website at WHOI.]