Nutrient Cycling MCQs (Quiz 13)

1. Which soil and nutrient combination would be most vulnerable to leaching losses?

Clay soil with phosphate ions, in a dry climate

Peat soil with ammonium ions, under moderate rainfall

Loam soil with potassium ions, under seasonal drought conditions

Sandy soil with nitrate ions, under heavy and frequent rainfall

2. Denitrification is most likely to occur under which soil conditions, and what type of bacteria carry it out?

Waterlogged soils; nitrogen-fixing bacteria such as Rhizobium

Dry sandy soils; aerobic decomposers

Well-aerated soils; autotrophic nitrifying bacteria

Waterlogged, anaerobic soils; anaerobic bacteria such as Pseudomonas

3. The principal reservoir of nutrients in sedimentary cycles is the ______________

Biosphere

Hydrosphere

Atmosphere

Lithosphere

4. Which process removes carbon dioxide directly from the atmosphere and stores it in plant biomass?

Combustion

Photosynthesis

Fermentation

Respiration

5. What is the primary contribution of decomposers to nutrient cycling in an ecosystem?

Converting solar energy into chemical energy stored in organic molecules

Absorbing carbon dioxide from the atmosphere for use in biosynthesis

Breaking down dead organic matter and releasing inorganic nutrients back into the soil and water

Synthesizing complex proteins that are passed on to consumer organisms

6. A farmer applies excess ammonium-based fertilizer to a well-aerated field. Over time, crop yield declines due to nitrogen loss. Which process is most directly responsible, and what is its first step?

Nitrification, beginning with the oxidation of NH₄⁺ to NO₂⁻, making nitrogen more susceptible to leaching

Ammonification, beginning with the breakdown of NH₄⁺ into organic nitrogen

Nitrogen fixation, beginning with the conversion of N₂ into NH₃

Denitrification, beginning with the reduction of NH₄⁺ to N₂

7. Weathering contributes to nutrient cycling by ___________________

Locking nutrients permanently in rocks

Making mineral nutrients available to ecosystems

Reducing soil fertility

Preventing mineral release

8. Ecological succession following a volcanic eruption depends heavily on _______________

All of these

Soil development

Nutrient accumulation

Weathering of volcanic material

9. Which nutrient cycle is least dependent on volcanic activity?

Sulfur cycle

Phosphorus cycle

Nitrogen cycle

Carbon cycle

10. Fresh volcanic deposits are gradually incorporated into nutrient cycles primarily through _____________

Respiration and weathering processes

Denitrification and decomposition processes

Photosynthesis and decomposition processes

Weathering and decomposition processes

Question 1 of 10

Nutrient Cycling MCQs (Quiz 13)

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