Water Quality & Management Flashcards
7 cards from real CFP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Water Quality & Management flashcards as text
Which process is primarily responsible for internal phosphorus loading in stratified, eutrophic lakes?
Answer: Anoxic sediment release of phosphorus under low redox conditions
Under anaerobic conditions in the hypolimnion, iron-phosphorus complexes dissolve and release phosphorus from sediments back into the water column.
A fish hatchery is experiencing elevated CO2 (>30 mg/L) in rearing tanks. The most appropriate immediate corrective action is:
Answer: Increase aeration or degassing to strip CO2
Mechanical aeration or cascade degassing rapidly strips excess CO2 from water by increasing the gas-liquid interface and driving off-gassing.
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:
Answer: Salmonids and sensitive cold-water species at chronic exposure levels
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.
Which physical characteristic of water has the greatest influence on the concentration of dissolved oxygen at saturation?
Answer: Temperature
As water temperature increases, the solubility of oxygen (and all gases) decreases, so warmer water holds less dissolved oxygen at saturation.
Alum (aluminum sulfate) is applied to fish ponds or lakes primarily to:
Answer: Flocculate suspended clay particles and precipitate phosphorus
Alum hydrolyzes to form aluminum hydroxide floc that binds clay particles and phosphorus, settling them to the sediment and improving water clarity.
In a recirculating aquaculture system (RAS), the biofilter converts toxic ammonia to less harmful nitrate through a two-step process. What are the two bacterial genera most associated with these steps?
Answer: Nitrosomonas and Nitrobacter
Nitrosomonas oxidizes ammonia to nitrite (step 1) and Nitrobacter oxidizes nitrite to nitrate (step 2) in aerobic nitrification.
When assessing the potential for herbicide impacts on fish in a treated water body, which measurement is most important to compare against toxicity data?
Answer: Measured herbicide concentration relative to LC50 values for target fish species
Comparing measured herbicide concentrations to species-specific LC50 values (lethal concentration for 50% of test organisms) is the standard risk assessment approach.