The concept of 'blue carbon' refers to the carbon captured by the world's oceanic and coastal ecosystems, particularly mangroves, salt marshes, and seagrasses. Unlike terrestrial forests, which store carbon primarily in biomass, these marine habitats sequester carbon predominantly in their sediments, where it can remain for millennia. Recent research highlights that although these ecosystems cover less than 2% of the ocean floor, they account for approximately 50% of the carbon buried in marine sediments. This remarkable efficiency has led to growing interest in their conservation as a climate mitigation strategy. However, scientists caution that when these habitats are degraded or destroyed, the stored carbon is released back into the atmosphere, turning them from carbon sinks into carbon sources. Therefore, protecting blue carbon ecosystems is not merely an environmental issue but a critical component of global climate policy.
❓ According to the passage, why are blue carbon ecosystems considered particularly important for climate mitigation?
A. A) They store carbon mostly in their above-ground biomass, similar to forests.
B. B) They cover a large portion of the ocean floor and thus capture vast amounts of carbon.
C. C) They sequester carbon in sediments for very long periods, despite their small area.
D. D) They release stored carbon quickly when degraded, which helps balance atmospheric levels.
✅ 正确答案
C) They sequester carbon in sediments for very long periods, despite their small area.
IELTS Reading Tips
Skim the questions first, underline keywords, then locate in the passage
Watch for paraphrasing; correct answers are often reworded
Be wary of absolute statements (all, always, never) — usually wrong
Pay attention to content after transition words (however, but, yet)
Manage time: about 20 minutes per passage; skip difficult questions first