Primary nitrite maximum

In the water column, ammonification and nitrification can sometimes lead to the formation of subsurface ammonium and nitrite concentration maxima that are usually located toward the base of the euphotic zone in stratified water columns. This is called the primary nitrite maximum. Some of this nitrite is also contributed by releases... 

Depth profiles from the eastern tropical North Pacific (Figure 24.8) show the effects of nitrogen metabolism under 02-deficient conditions. The thermocline is characterized by a sharp decline in O2 concentrations that coincides with increasing nitrate and phosphate concentrations. The oxycline is produced by the respiration of sinking POM under vertically stagnant conditions. Below the oxycline, in depths where O2 concentrations are suboxic, phosphate concentrations continue to increase, but at a slower rate. In contrast, nitrate concentrations decline and reach a mid-water minimum that coincides with a nitrite maximum. The latter is referred to as the secondary nitrite maximum. (At this site the primary nitrite maximum is located at 50 m.)... 

Primary nitrite maximum Subsurface concentration maximum in nitrite found toward the base of the euphotic zone in stratified water columns. Mainly caused by ammonification and nitrification. 

Lomas, M. W., and Lipschultz, F. (2006). Forming the primary nitrite maximum Nitrifiers or phytoplankton Limnology And Oceanography 51, 2453—2467. 

Olson, R. J. (1981a). N tracer studies of the primary nitrite maximum. Jouma/ of Marine Research i9, 203-226. 

Ward, B. B., Olson, R. J., and Perry, M. J. (1982). Microbial nitrification rates in the primary nitrite maximum off southern-Califomia. Deep-Sea Research Part A-Oceanographic Research Papers 29,247—255. 

CoUos, Y., and Slawyk, G. (1983). Ammonium and nitrate in the tropical and equatorial Atlantic Relations with the primary nitrite maximum. Mar. Biol. Lett. 4, 295—308. 

Figure l6.11 Vertical distributions of Chlorophyll a, [N02 + NOs ], and [N02 ] for the water column at Station ALOHA in October 1992. The conspicuous N02 maximum beginning at approximately 100 m is positioned below the deep Chlorophyll a maximum layer (DCML) and is coincident with the top of the nitracline.This primary nitrite maximum (PN M) is further divided into upper and lower regions (UPNM and LPNM, respectively) with a tailing of the LPNM. These m or features are the result of competing microbiological N02 production and utilization processes as shown in Fig. 16.2. From Dore and Karl (1996b).

Figure 16.12 Temporal and spatial (depth) variations in the primary nitrite maximum layer at Station ALOHA. (A) Shown are five representative profiles of NO2 between 80 and 200 m from February 1990 to September 1992 displayii the two-peaked structure (U = UPNM and L = LPNM) of the general feature. Note concentration variations and changes in reference depths of the key features. A = February 1990, B = July 1990, C = December 1990, D = October 1991, E = September 1992. From Dore and Karl (1996b). (B) Temporal variations in the positions of the UPNM and LPNM relative to the nitracline. Shown also are the mean depths for these features over the observation period. From Dore and Karl (1996b).

---