Which internal processes are considered in watershed nutrient budgets to balance net gains or losses?

Which internal processes are considered in watershed nutrient budgets to balance net gains or losses?

• A. Photosynthesis and respiration
• B. External inputs from rivers
• C. Mineralization, immobilization, sorption/desorption
• D. Evaporation and precipitation

Answer: (C)

Internal nutrient transformations in a watershed determine how the pool of available nutrients is stored, released, or kept in balance. Mineralization breaks down organic matter and releases inorganic nutrients that can then be used or lost, while immobilization pulls inorganic nutrients into microbial biomass, temporarily removing them from the available pool. Sorption and desorption describe nutrients attaching to or releasing from soil and sediment particles, acting as a buffer that stores nutrients and then returns them when conditions change. These processes together regulate how much nutrient is retained versus lost, helping to balance net gains or losses in the budget. Photosynthesis and respiration mainly address carbon and energy flow, not the direct transformation of inorganic nutrients. External inputs from rivers introduce nutrients but are not internal processing. Evaporation and precipitation affect water movement and concentrations but do not describe how nutrients are transformed and stored inside the watershed.

Internal nutrient transformations in a watershed determine how the pool of available nutrients is stored, released, or kept in balance. Mineralization breaks down organic matter and releases inorganic nutrients that can then be used or lost, while immobilization pulls inorganic nutrients into microbial biomass, temporarily removing them from the available pool. Sorption and desorption describe nutrients attaching to or releasing from soil and sediment particles, acting as a buffer that stores nutrients and then returns them when conditions change. These processes together regulate how much nutrient is retained versus lost, helping to balance net gains or losses in the budget.

Photosynthesis and respiration mainly address carbon and energy flow, not the direct transformation of inorganic nutrients. External inputs from rivers introduce nutrients but are not internal processing. Evaporation and precipitation affect water movement and concentrations but do not describe how nutrients are transformed and stored inside the watershed.