Nutrient Cycling MCQs (Quiz 13)

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

All of these

Nutrient accumulation

Soil development

Weathering of volcanic material

2. 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

Synthesizing complex proteins that are passed on to consumer organisms

Converting solar energy into chemical energy stored in organic molecules

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

Atmosphere

Hydrosphere

Biosphere

Lithosphere

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

Weathering and decomposition processes

Denitrification and decomposition processes

Photosynthesis and decomposition processes

Respiration and weathering processes

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

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

Peat soil with ammonium ions, under moderate rainfall

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

Fermentation

Combustion

Respiration

Photosynthesis

7. Weathering contributes to nutrient cycling by ___________________

Reducing soil fertility

Making mineral nutrients available to ecosystems

Locking nutrients permanently in rocks

Preventing mineral release

8. 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?

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

Denitrification, beginning with the reduction of NH₄⁺ to N₂

Nitrogen fixation, beginning with the conversion of N₂ into NH₃

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

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

Well-aerated soils; autotrophic nitrifying bacteria

Dry sandy soils; aerobic decomposers

Waterlogged soils; nitrogen-fixing bacteria such as Rhizobium

Waterlogged, anaerobic soils; anaerobic bacteria such as Pseudomonas

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

Sulfur cycle

Nitrogen cycle

Phosphorus cycle

Carbon cycle

Question 1 of 10

Nutrient Cycling MCQs (Quiz 13)

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