Image caption
Plants and trees in coastal ecosystems absorb carbon dioxide through photosynthesis. Some of that carbon returns to the atmosphere as methane and carbon dioxide, but some is buried in the soil and some is carried farther away and buried in ocean sediments. Cut off from the atmosphere, these underwater soils and sediments make an excellent long-term sink for carbon. NOAA Climate.gov graphic adapted from original by Sarah Battle, NOAA Pacific Marine Environmental Laboratory.