What is blue carbon?

Answer: A. BLUE CARBON is the carbon captured by OCEANS and COASTAL ECOSYSTEMS. BLUE CARBON is the carbon stored in MARINE AND COASTAL ECOSYSTEMS, particularly: - MANGROVES - SEAGRASS MEADOWS - TIDAL SALT MARSHES - KELP FORESTS (sometimes included) These ecosystems sequester carbon at rates per unit area many times faster than terrestrial forests, and they store it in waterlogged sediments where decomposition is slow, locking carbon away for centuries to millennia. Why blue carbon matters: - Mangroves alone are estimated to store more than 4x as much carbon per hectare as tropical rainforests when sediment storage is included. - Coastal ecosystems are highly threatened (mangroves lost at 1-2% per year globally). - DESTROYING these ecosystems RELEASES MASSIVE STORED CARBON — making their protection a key climate mitigation strategy. India's Sundarbans (largest mangrove forest in the world, shared with Bangladesh) is a major blue carbon reservoir. India is part of the International Blue Carbon Partnership and various global initiatives. Distractors: (B) Carbon in forest biomass / agricultural soils = GREEN CARBON (terrestrial sequestration). (C) Carbon in fossil fuels = BROWN CARBON / FOSSIL CARBON (pre-industrial geologically locked carbon). (D) Carbon in atmosphere = atmospheric CO2 / GHG concentration (not 'blue carbon'). Source: IPCC AR6 Working Group I / UN Environment Programme blue carbon initiative / syllabus Biology Environmental Issues.