Coastal marine ecosystems, such as seagrass, beds account for roughly 70% of organic carbon uptake from the marine environment, making them Blue Carbon sink hotspots. Seagrass habitats are reported to sequester organic carbon at a rate that is 35 times faster than that of tropical rainforests.
Seagrass are a diverse group of flowering plants that have adapted to grow and reproduce whilst submerged in seawater, typically in shallow marine waters down to a depth where approximately 11% of surface light reaches the bottom. Seagrasses cover only 0.1-0.2% of the coastal waters, yet they play a significant role in the coastal zone by supplying a variety of critical ecosystem products and services.
Seagrass leaves also reduce hydrodynamic stress by attenuating currents and waves, improve light conditions by trapping suspended sediment and nutrients, and increase pH by absorbing CO2 creating a favorable habitat for organisms, greatly improving biodiversity. The carbon sequestration rate of seagrass meadows is estimated to be 83,000kg per square kilometer per year.
Seagrasses inhabit coastal environments and are therefore subjected to numerous anthropogenic activities such as sewage disposal, mariculture, propeller boating activities, destructive fishing, construction works and dredging, threatening their extinction. Disturbed or dead seagrass can release buried sedimentary carbon and other greenhouse gasses such as methane and nitrous oxide.