Table 2 PRIMARY PRODUCTIVITY DATA AND CALCULATIONS

Winkler Titration Mean Results

Initial Bottle (IB) = 4.92 ppm
Light Bottle (LB) = 5.43 ppm
Dark Bottle (DB) = 4.33 ppm

Calculations:
Net Productivity = (LB-IB) x 356/ Time = 0.51 x 356/7 = 25.9 mgC/m3/hour

Gross Product. = (LB-DB) x 356/ Time = 1.12 x 356/7 = 57.0 mgC/m3/hour

Respiration = Gross -Net = 31.1 mgC/m3hour

P/R=57.0/31.1 = 1.8

Comparison with Past Results:

Data table explanation:
Columns:           
1) Date 
2) Net Productivity( mgC/m3/hr)
3) same, (gC/m3/day) 
4) No.Hours
5) Gross Productivity( mgC/m3/hr)
6) same, (gC/m3/day)
7) P/R

Fall Results

11/27/96 25.9 0.31 7 57.0 0.67 1.8
12/9/80 39.2 0.47 3 83.1 1.00 1.9
12/9/80 73.0 0.91 6 106.8 1.32 3.2
12/9/80 41.5 0.50 12 119.8 1.44 1.5
11/20/75 29.4 0.35 4 35.6 0.43 5.7
11/20/75 8.0 0.10 8 40.5 0.49 1.2

-Spring Results
4/21/77 11.6 0.13 12 40.4 0.48 1.4
4/21/77 24.7 0.30 7.5 107.8 1.30 1.3
4/25/78 20.5 0.24 4 36.5 0.44 2.3
Means 30.4 0.37 69.7 0.84 2.1


Using the mean net primary productivity of 0.37 gC/mI\3/day along with the area
of Middle Loch (3 x 1 km or 3 million m1\2) and a mean Secchi depth of 1.5 m,
production amounts to about 1.7 tonnesC / day or over 600 tonnesC / year.  
