CFP Water Quality & Management 3

Question 1

Which process is primarily responsible for internal phosphorus loading in stratified, eutrophic lakes?

Accepted Answer

Anoxic sediment release of phosphorus under low redox conditions

Answer

Under anaerobic conditions in the hypolimnion, iron-phosphorus complexes dissolve and release phosphorus from sediments back into the water column.

Question 2

A fish hatchery is experiencing elevated CO2 (>30 mg/L) in rearing tanks. The most appropriate immediate corrective action is:

Accepted Answer

Increase aeration or degassing to strip CO2

Answer

Mechanical aeration or cascade degassing rapidly strips excess CO2 from water by increasing the gas-liquid interface and driving off-gassing.

Question 3

The maximum contaminant level (MCL) for nitrate in US drinking water is 10 mg/L as nitrogen. High nitrate in aquaculture source water is most concerning for:

Accepted Answer

Salmonids and sensitive cold-water species at chronic exposure levels

Answer

Salmonids and other sensitive cold-water fish are more susceptible to chronic nitrate toxicity than warm-water generalists, with sublethal effects on growth and immune function.

Question 4

Which physical characteristic of water has the greatest influence on the concentration of dissolved oxygen at saturation?

Accepted Answer

Temperature

Answer

As water temperature increases, the solubility of oxygen (and all gases) decreases, so warmer water holds less dissolved oxygen at saturation.

Question 5

Alum (aluminum sulfate) is applied to fish ponds or lakes primarily to:

Accepted Answer

Flocculate suspended clay particles and precipitate phosphorus

Answer

Alum hydrolyzes to form aluminum hydroxide floc that binds clay particles and phosphorus, settling them to the sediment and improving water clarity.

(CFP) Certified Fisheries Professional Practice Test

(CFP) Certified Fisheries Professional Practice Test

CFP Water Quality & Management 3