Question 5: Primary Productivity (4 points)

A water sample from a lake ecosystem was analyzed for dissolved oxygen content. The results are summarized in the table below.

?	Dissolved Oxygen Content (mg/L)
Initial conditions	7.20
Dark conditions (incubated in the dark overnight)	4.10
Light conditions (incubated under a grow light overnight)	10.30

a) Calculate the net productivity. (1 point)

b) Calculate the gross productivity. (1 point)

c) Calculate the loss of oxygen due to respiration. (1 point)

d) Calculate the net amount of carbon fixed by the lake sample in mg C/L. (1 point)mg O₂/L ? 0.698 = mL O₂/LmL O₂/L ? 0.536 = mg carbon fixed/L

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1 2 3 4 5 6 7 8 9 (2) (3 4 5 7 8 9 0 3 2 2 4 5 7 8 0 9 1 3 4 5 (6) (7 (8) 9 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 (2) (3 4 5 7 8 9 0 3 2 2 4 5 7 8 0 9 1 3 4 5 (6) (7 (8) 9 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 (2) (3 4 5 7 8 9 0 3 2 2 4 5 7 8 0 9 1 3 4 5 (6) (7 (8) 9 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 (2) (3 4 5 7 8 9 0 3 2 2 4 5 7 8 0 9 1 3 4 5 (6) (7 (8) 9 2 3 4 5 6 7 8 9