Detailed Explanation:

Answer: Option 1 — Carbon captured by oceans and coastal ecosystems.

Blue Carbon refers to the carbon captured and stored by oceanic and coastal ecosystems such as mangroves, seagrasses, and salt marshes. Although these vegetated coastal habitats cover less than 0.5% of the seabed, they are responsible for storing more than 50% (and potentially up to 70%) of all carbon stored in ocean sediments, making them highly efficient carbon sinks. This is distinct from 'green carbon' which is captured by terrestrial forests and agricultural soils.

📝 Short Notes: Blue Carbon Ecosystems

• Blue Carbon: Carbon captured and stored by coastal and marine ecosystems (mangroves, seagrasses, salt marshes, and tidal wetlands).
• High Efficiency: These ecosystems cover less than 0.5% of the seabed but store 50-70% of all carbon in ocean sediments.
• Sequestration Rate: Coastal ecosystems can sequester carbon at rates up to 40 times faster than terrestrial forests.
• Long-term Storage: Carbon can remain stored in coastal sediments for thousands of years if undisturbed.
• Co-benefits: Blue carbon ecosystems also provide coastal protection, biodiversity habitat, fisheries support, and water filtration.
• Threats: Coastal development, aquaculture expansion, pollution, and climate change threaten these ecosystems, releasing stored carbon back into the atmosphere.
• Conservation Importance: Protecting and restoring blue carbon ecosystems is crucial for climate mitigation and adaptation strategies.