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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
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
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
“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)
