CWD Water Quality & Management 3

Question 1

Which process converts ammonium (NH4+) to nitrate (NO3-) in wetland soils?

Accepted Answer

Nitrification

Answer

Nitrification is the aerobic microbial oxidation of ammonium to nitrate, occurring in the thin oxidized surface layer of wetland soils.

Question 2

A wetland delineator observes iron-rich orange precipitates coating stream cobbles downstream of a wetland. This indicates:

Accepted Answer

Reducing conditions within the wetland releasing ferrous iron that oxidizes upon exposure to air

Answer

Ferrous iron (Fe2+) released under anaerobic wetland conditions oxidizes to ferric iron (Fe3+) when exposed to oxygen, precipitating as iron oxyhydroxide coatings on stream substrates.

Question 3

Total Maximum Daily Loads (TMDLs) are established under which section of the Clean Water Act?

Accepted Answer

Section 303(d)

Answer

Section 303(d) of the Clean Water Act requires states to identify impaired water bodies and establish TMDLs to restore water quality standards.

Question 4

Which macrophyte growth form is most efficient at intercepting non-point source sediment runoff entering a wetland?

Accepted Answer

Dense emergent vegetation such as cattails and bulrushes along the wetland edge

Answer

Dense emergent vegetation along wetland margins physically intercepts and slows overland flow, allowing sediment particles to settle before entering open water.

Question 5

Sulfate reduction in anaerobic wetland soils produces which compound that can be toxic to plants?

Accepted Answer

Hydrogen sulfide (H2S)

Answer

Sulfate-reducing bacteria in anaerobic sediments produce hydrogen sulfide, which is toxic to plant roots at elevated concentrations and contributes to the characteristic rotten-egg odor.

(CWD) Certified Wetland Delineator Practice Test

(CWD) Certified Wetland Delineator Practice Test

CWD Water Quality & Management 3