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IB Biology HL C4.2.18 Carbon Sinks and Sources Questions

Carbon sinks absorb more carbon than they release; forests, soils and oceans are examples. Carbon sources release more than they absorb, including fossil-fuel combustion.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Explain that a carbon sink stores more carbon than it releases, while a carbon source releases more than it absorbs.
  • Classify forests, soils and oceans as sinks and fossil-fuel combustion as a source from the direction of carbon transfer.

IB Biology HL C4.2.18 Carbon Sinks and Sources Questions question 1

[Maximum number: 2]

The graph shows carbon dioxide ( CO2\mathrm{CO}_{2} ) concentration in the atmosphere during the past 800000 years. The data was produced by measuring the CO2\mathrm{CO}_{2} concentration of air bubbles trapped in cores of Antarctic ice.

Figure for Question IB Biology HL C4.2.18 Carbon Sinks and Sources Questions question 1 — IB Biology HL

The graph shows long-term fluctuations in atmospheric CO2\mathrm{CO}_{2} concentration of about 80 ppm . The decreases in CO2\mathrm{CO}_{2} concentration are probably due to oceans acting as a sink by holding large quantities of dissolved CO2\mathrm{CO}_{2}.

Identify two other examples of natural sinks that can remove carbon from the carbon cycle and reduce atmospheric CO2\mathrm{CO}_{2} concentration.

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