Rank coastal blue carbon ecosystems by their potential carbon storage per unit area and explain the general order.

• A. Mangroves store the most carbon per area in soils, followed by salt marshes, then seagrasses; differences depend on soil depth, turnover, and burial rates.
• B. Seagrasses store the most carbon per area, followed by mangroves, then salt marshes.
• C. Salt marshes store more carbon per area than mangroves and seagrasses combined.
• D. All blue carbon ecosystems store carbon at the same rate per unit area.

Answer: (A)