Building Blue Carbon Projects - An Introductory Guide

1.1 Blue Carbon Ecosystems

The Blue Carbon concept is currently focused on the following three marine and coastal ecosystems: mangrove forests, saltwater marshes, and seagrass meadows.

Mangrove Forests

Mangrove forests are found within intertidal areas of tropical and subtropical regions. Mangroves are a type of salt-tolerant vegetation that includes trees and shrubs with extensive below-surface root structures and deep sediments. These deep layers of sediments store anaerobic carbon that when exposed, oxidize and become a source of greenhouse gas (GHG) emissions. Up to the equivalent of 3,754 tons of carbon per hectare has been found in the first meter of soil for intact

“The  survival of  the mangroves  in  the   coastal ecosystem is the key to preserving sustainability in our emirate and to guarantee a better environmental  future.”

H.E. Razan Khalifa Al Mubarak Secretary General, Environment Agency Abu Dhabi (EAD)

mangrove forests (Donnato et al ., 2011). However, the carbon stocks of mangrove forests are not uniform. The depth of carbon-rich soil relates to the geomorphology of an environment, and there are differences in carbon storage between estuarine and oceanic mangroves where the substrate material differs. Despite the variations however, mangroves remain among the most carbon-rich forest environments (Sifleet et al ., 2011). In addition to their role in carbon sequestration, mangroves provide a host of other ecosystem services. Their extensive root structures provide shelter and habitat for commercially and recreationally important fish and shellfish, as well as filtering sediments and pollutants from water, improving its overall quality. Their presence also provides a buffer between shores and incoming storms, and they aid in keeping soils in place, preventing shoreline erosion. Increasingly mangroves provide a source of revenue derived from ecotourism, linked with recreational and spiritual values, as well as providing natural resources to indigenous communities residing in mangrove-rich coastal areas. Mangroves also provide fuel for cooking (e.g., charcoal) and construction materials (e.g., wood). Mangrove ecosystem services alone – excluding carbon cycling – have been valued at U.S. $193,845 per hectare of intact ecosystem (De Groot et al ., 2011). Saltwater marshes are primarily found in temperate regions, within intertidal zones, and contain partially and fully submerged vegetation suited to both fresh and salt water. These ecosystems provide habitat for a variety of wildlife including fish, shellfish, invertebrates, and numerous bird species, both commercially and recreationally important. It is estimated that salt marshes contain between 900 and 1,700 tons of carbon per hectare, with an approximate yearly habitat loss of up to two percent (Sifleet et al ., 2011). When healthy, saltwater marshes also filter nutrients and sediment from passing water, protect against wave Saltwater Marshes

Building Blue Carbon Projects An Introductory Guide

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