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Q29 (IAS/2021) Environment & Ecology › Climate Change & Global Initiatives › Carbon sequestration and storage Official Key

What is blue carbon?

Result
Your answer: —  ·  Correct: A
Explanation

The correct answer is Option 1.

Blue carbon refers to the carbon stored in coastal and marine ecosystems. These ecosystems, particularly mangroves, tidal marshes, and seagrass meadows, are highly efficient at sequestering atmospheric carbon dioxide and storing it in their biomass and underlying organic-rich soils.

Why Option 1 is correct:

  • Coastal ecosystems can sequester carbon at rates much higher per unit area than terrestrial forests.
  • Unlike terrestrial soils, marine sediments are often anaerobic, allowing carbon to remain stored for millennia if undisturbed.

Why other options are incorrect:

  • Option 2: This describes Green Carbon, which is sequestered by land-based ecosystems like forests.
  • Option 3: This refers to Fossil Carbon, which has been stored over geological timescales.
  • Option 4: Carbon in the atmosphere is primarily in the form of greenhouse gases (CO2 or Methane).
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
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PROVENANCE & STUDY PATTERN
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Don’t just practise – reverse-engineer the question. This panel shows where this PYQ came from (books / web), how the examiner broke it into hidden statements, and which nearby micro-concepts you were supposed to learn from it. Treat it like an autopsy of the question: what might have triggered it, which exact lines in the book matter, and what linked ideas you should carry forward to future questions.
Q. What is blue carbon? [A] Carbon captured by oceans and coastal ecosystems [B] Carbon sequestered in forest biomass and agricultural soi…
At a glance
Origin: Books + Current Affairs Fairness: Low / Borderline fairness Books / CA: 2.5/10 · 7.5/10
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This is a textbook 'Sitter' from standard static sources (Shankar IAS, Chapter 21). It represents the 'Term Definition' genre of UPSC questions. If you see a color-coded environmental term (Blue, Green, Black, Brown), you must immediately map its definition and distinct source.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Does "blue carbon" refer to carbon captured by oceans and coastal ecosystems?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 21: Mitigation Strategies > z!,2,2. Blue Carbon > p. 282
Presence: 5/5
“• Blue Carbon refers to coastal, aquatic and marine carbon sinks held by the indicative vegetation, marine organisms and sediments. • In particular, coastal ecosystems such as tidal marshes, mangroves, and seagrasses remove carbon from the atmosphere and ocean, storing it in plants and depositing it in the sediment below them by natural processes.”
Why this source?
  • Provides an explicit definition: Blue Carbon are coastal, aquatic and marine carbon sinks held by vegetation, organisms and sediments.
  • Specifically names tidal marshes, mangroves and seagrasses as ecosystems that remove and store carbon.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 21: Mitigation Strategies > The Blue Carbon Initiative > p. 283
Presence: 4/5
“o The Blue Carbon Initiative is the first integrated program with a comprehensive and coordinated global agenda focused on mitigating climate change through the conservation and restoration of coastal marine ecosystems.”
Why this source?
  • Describes the Blue Carbon Initiative as focused on mitigating climate change through conservation and restoration of coastal marine ecosystems.
  • Links the term to coastal/marine ecosystem management for carbon mitigation.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 18: Ocean Acidification > 18.I. OCEAN ACIDIFICATION > p. 263
Presence: 4/5
“Oceans are an important reservoir for CO absorbing a significant quantity of it (one-third) produced by anthropogenic activities and effectively buffering climate change. Ocean acidification is the change in ocean chemistry - lowering of ccean pH (i.e. increase in concentration of hydrogen ions) driven by the uptake of carbon compounds by the ocean from the atmosphere' As the uptake of atmospheric carbon dioxide by the ocean increases, the concentration of hydrogen ions in the ocean increases, the concentration of carbonate ions decreases, the pH of the oceans decreases and the oceans become less alkaline. This process is known as ocean acidification.”
Why this source?
  • States oceans absorb a significant portion (about one-third) of anthropogenic CO2, making them an important carbon reservoir.
  • Explains ocean uptake of CO2 and its chemical consequences, supporting the idea of oceans capturing carbon.
Statement analysis

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Statement analysis

This statement analysis shows book citations, web sources and indirect clues. The first statement (S1) is open for preview.

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Statement analysis

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