Nutrient Cycling MCQs (Quiz 13)

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

Photosynthesis and decomposition processes

Denitrification and decomposition processes

Weathering and decomposition processes

Respiration and weathering processes

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

Photosynthesis

Fermentation

Combustion

Respiration

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

All of these

Nutrient accumulation

Weathering of volcanic material

Soil development

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

Sulfur cycle

Nitrogen cycle

Carbon cycle

Phosphorus cycle

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

Biosphere

Atmosphere

Hydrosphere

Lithosphere

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

Waterlogged, anaerobic soils; anaerobic bacteria such as Pseudomonas

Dry sandy soils; aerobic decomposers

Waterlogged soils; nitrogen-fixing bacteria such as Rhizobium

Well-aerated soils; autotrophic nitrifying bacteria

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

Peat soil with ammonium ions, under moderate rainfall

Clay soil with phosphate ions, in a dry climate

Sandy soil with nitrate ions, under heavy and frequent rainfall

Loam soil with potassium ions, under seasonal drought conditions

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

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

Converting solar energy into chemical energy stored in organic molecules

Synthesizing complex proteins that are passed on to consumer organisms

9. Weathering contributes to nutrient cycling by ___________________

Preventing mineral release

Making mineral nutrients available to ecosystems

Reducing soil fertility

Locking nutrients permanently in rocks

10. 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

Nitrogen fixation, beginning with the conversion of N₂ into NH₃

Denitrification, beginning with the reduction of NH₄⁺ to N₂

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

Question 1 of 10

Nutrient Cycling MCQs (Quiz 13)

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