NO2 + NO~ based on the results of the BACI analysis
(Fig. 1). Station 7 had elevated NO 2 q- NO3
concentrations compared I:o the other marsh stations
presumably due to the addition of river water
in the region by the Bohemia structure and spillway
(Fig. 3). Mean pre- and post-diversion Mississippi
River water NO 2 -1- NO 3 concentrations
ranged from 1.2 to 1.6 ppm, while the marsh water
quality monitoring stations ranged from 0.1 to 0.5
ppm, suggesting rapid reduction in NO,, + NO3
levels as river water entered the estuary. This is supported
by the salinity mixing diagram (Fig. 4),
which indicated that the Breton Sound wedands
and shallow waters were acting as a strong sink for
NO 2 + NO~ (see Liss [1976] for mixing diagram
discussion). When the posr-diversion data was analyzed
by seasons (Fig. 5), nitrite + nitrate