Table 6.1 Comparison of historic and recent NO3 + NO2 (pM) concentrations in the Yaquina 
Estuary. There are statistically significant differences in median concentrations between 
historic and recent data for all zones and both seasons (Mann-Whitney Rank Sum, n<0.001). 
Historic 
Recent 
Median 
Time Interval 
(Sample Size) 
Median 
Time Interval 
(Sample Size) 
Zone 1 
Dry 
6.5 
1974-1984 (157) 
10.0 
1998-2006 (1127) 
Wet 
19.8 
1974-1984 (65) 
8.5 
1998-2004 (520) 
Zone 2 
Dry 
14.0 
1971-1984 (247) 
9.8 
1998-2004 (919) 
Wet 
69.6 
1971-1984(148) 
52.6 
1998-2004 (354) 
Table 6.2 Comparison of historic and recent PO 4 (pM) concentrations in the Yaquina 
Estuary. There are statistically significant differences in median concentrations between 
historic and recent data for all zones and both seasons with the exception of Zone 2 wet season 
(Mann-Whitney Rank Sum, p<0.05) 
Historic 
Recent 
Median 
Time Interval 
(Sample Size) 
Median 
Time Interval 
(Sample Size) 
Zone 1 
Dry 
1.01 
1963-1.984 (223) 
1.25 
1998-2006(1126) 
Wet 
0.83 
1962- 1984(129) 
0.59 
1998-2004 (519) 
Zone 2 
Dry 
0.74 
1963-1984 (308) 
0.65 
1998-2004 (919) 
Wet 
0.54 
1962-1984 (212) 
0.49 
1998-2004 (354) 
45 
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