FRQ 01 / 088 points total
EcologyChange
Eutrophication in a Freshwater Lake
| Sampling Date | Nitrate (mg/L) | Phosphate (mg/L) | Dissolved O₂ (mg/L) |
|---|---|---|---|
| June 1 (baseline) | 0.4 | 0.05 | 8.2 |
| July 1 (after farm runoff) | 3.6 | 0.42 | 7.4 |
| August 1 | 2.1 | 0.30 | 3.1 |
| September 1 | 0.9 | 0.12 | 1.4 |
(a)Using the data in Table 1, describe the trend in dissolved oxygen levels over the sampling period. [1 pt]
(b)Explain the mechanism by which the runoff in early July causes the long-term decline in dissolved oxygen. [3 pts]
(c)Predict the impact of the September O₂ level on the fish community, and justify your prediction. [2 pts]
(d)Identify TWO management practices that could reduce future nutrient runoff into the lake. [2 pts]