THE OCEANOGRAPHY SOCIETY PACIFIC BASIN MEETING, July 1994, p.60

Nitrite distributions and dynamics at Station ALOHA

J.E. Dore and D.M. Karl

Nitrite, the redox intermediate between ammonium and nitrate, is a useful indicator of oceanic zones of rapid nitrogen cycle activity. Until the recent advent of chemiluminescent analytical techniques, detailed assessments of its water-column distributions and their temporal variability were made extremely difficult by the low concentrations found in open-ocean environments (nanomolar to sub-nanomolar). We report here on our chemiluminescent measurements of nitrite concentrations at Station ALOHA from September 1989 through February 1994; we believe that this is the first nitrite data set using the chemiluminescent method from this region, and the first multi-year time-series nitrite data set from the Pacific. Deep (1000-5000 dbar) and midwater (200-1000 dbar) profiles, as well as estimates of turnover rates, are compared with published data from the Sargasso and Caribbean Seas (Zafiriou et al., 1992). In the upper 200 dbar, temporal variability of the primary nitrite maximum is addressed, and hypotheses regarding its formation and maintenance are presented.