Which of the following biogeochemical cycles can be most aptly called both sedimentary and gaseous?

Correct option is B

Introduction

• Biogeochemical cycles describe the movement of chemical elements through biotic (living) and abiotic (non-living) components of the Earth.
• These cycles are traditionally classified into two types:
• Gaseous cycles: Major reservoir is the atmosphere (e.g., nitrogen, carbon)
  
• Sedimentary cycles: Major reservoir is Earth's crust (e.g., phosphorus, sulfur)
  
• However, some cycles exhibit characteristics of both types, making them hybrid cycles.

Information Booster:

• Sulfur Cycle Processes:
• Atmospheric oxidation: H₂S → SO₂ → SO₄²⁻ (acid rain formation)
• Biological reduction: Sulfate-reducing bacteria convert SO₄²⁻ to H₂S
• Weathering: Releases sulfates from rocks into soil and water
• Volcanic activity: Major natural source of atmospheric sulfur
• Environmental Significance:
• Acid rain: SO₂ + H₂O → H₂SO₄
• Climate regulation: DMS affects cloud formation
• Industrial impact: Fossil fuel combustion releases stored sulfur
• Major long-term reservoir is Earth's crust
• Gaseous Phase Components:
• Hydrogen sulfide (H₂S) - released from volcanic activity, decomposition
• Sedimentary Phase Components:
• Sulfate minerals in rocks and soil (gypsum, pyrite)
• Organic sulfur in fossil fuels (coal, petroleum)
• Sulfate ions (SO₄²⁻) in ocean sediment

Additional knowledge:

• ​Carbon Cycle - Primarily gaseous
  
• While sedimentary rocks contain carbonates, the active cycling is predominantly atmospheric
• Nitrogen Cycle - Primarily gaseous
• 78% of atmosphere is N₂
  
• Gaseous exchange through N₂, N₂O, NH₃ is primary
• Phosphorus Cycle - Purely sedimentary
• NO gaseous phase at all (no stable gaseous compounds)
• Reservoir is entirely in rocks, soil, and sediments