U.S. flag An official website of the United States government.
				Here's how you know we're official. **Official websites use .gov** A **.gov** website belongs to an official government organization in the United States.
 **Secure websites use HTTPS** A small lock or **https://** means you’ve safely connected to a .gov website. Share sensitive information only on official, secure websites.


Toggle navigation Toggle search National Ocean Service National Oceanic and Atmospheric Administration
 Search
					Search National Ocean Service


Home
				Ocean Facts

				Topics
					Explore All Topics 
                        Arctic 
                        Careers 
                        Economy 
                        Ecosystems 
                        Geodesy 
                        Hazards 
                        International
                        Navigation 
                        Observations 
                        Ocean 
                        Recreation 
                         Sea Level Rise 
                        Story Maps 
                        Tools
                
                			Education

				
				News
				Podcasts
				Video
				Images
				About Us


1. Home
2. Topics
3. Coastal Blue Carbon

Coastal Blue Carbon The world's coastal ecosystems — coastal salt marshes, mangrove forests, and seagrass meadows — are incredibly efficient at capturing and storing large quantities of carbon.


What is Coastal Blue Carbon? Scientists are testing how fast soil is building up in this marsh using a device called a Surface Elevation Table on Maryland's Eastern Shore. Scientists are testing how fast soil is building up in this marsh on Maryland's Eastern Shore. Recording this data over time in a variety of marshes around Chesapeake Bay may yield new insights about whether the increase in marsh elevations can keep pace with rising sea level in the estuary. Healthy coastal habitat is not only important for seafood and recreation, it also plays an important role in reducing climate change. Salt marshes, mangroves, and seagrass beds absorb large quantities of the greenhouse gas carbon dioxide from the atmosphere and store it, thus decreasing the effects of global warming. These types of habitat are known as carbon sinks and contain large stores of carbon accumulated over hundreds to thousands of years. Using more scientific lingo, coastal blue carbon is the carbon captured by living coastal and marine organisms and stored in coastal ecosystems. Salt marshes, mangroves, and seagrass beds play two important roles: **Carbon sequestration** — the process of capturing carbon dioxide from the atmosphere, measured as a rate of carbon uptake per year.
							**Carbon storage** — the long-term confinement of carbon in plant materials or sediment, measured as a total weight of carbon stored. NOAA Blue Carbon Enterprises Lessen Climate Change Damage
 fast facts
 NOAA Blue Carbon
 white paper
 Valuing Blue Carbon in Wetlands
 video
 Why is it important? MIT Sea Grant coastal ecologist Julie Simpson takes samples from a sediment core taken inside an eelgrass bed MIT Sea Grant coastal ecologist Julie Simpson takes samples from a sediment core taken inside an eelgrass bed. This research is part of an ongoing project in collaboration with several partners to determine how much carbon is stored in eelgrass beds in the North Atlantic region. Julie is shown here in West Falmouth, Massachusetts. Current studies suggest that mangroves and coastal wetlands annually sequester carbon at a rate ten times greater than mature tropical forests. They also store three to five times more carbon per equivalent area than tropical forests. Most coastal blue carbon is stored in the soil, not in above-ground plant materials as with tropical forests. Coastal habitats are important for capturing carbon—but their destruction poses a great risk. When these habitats are damaged or destroyed, it is not only their carbon sequestration capacity that is lost. Carbon stored in the habitats can also be released, contibuting to increased levels of greenhouse gases in the atmosphere. Unfortunately, coastal habitats around the world are being lost at a rapid rate, largely due to coastal development for housing, ports, and commercial facilities. Bringing Wetlands to Market
 podcast
 What is Blue Carbon?
 ocean fact
 The Climate Mitigation Opportunity You've Never Heard Of
 video
 Coastal Blue Carbon Sequestration 101 a graphic showing a simplified model of the carbon cycle This diagram illustrates the mechanisms by which carbon moves into and out of coastal wetlands: **(1)** Carbon dioxide in the atmosphere is taken in by trees and plants during the process of photosynthesis. This is called sequestration. **(2**) Dead leaves, branches, and roots containing carbon are buried in the soil, which is frequently, if not always, covered with tidal waters. This oxygen-poor environment causes very slow breakdown of the plant materials, resulting in significant carbon storage. **(3)** A small amount of carbon is lost back to the atmosphere through respiration, while the rest is stored in the leaves, branches, and roots of the plants. *This diagram is adapted from a figure in Sutton-Grier et al. 2014 Marine Policy* Coastal wetland ecosystems (salt marshes, mangroves, and seagrass beds) can store large quantities carbon for two main reasons: Their plants usually grow a lot each year, and in the process, capture (or **sequester**) large amounts of carbon dioxide (CO2).
							Their soils are largely anaerobic (without oxygen) so carbon that gets incorporated into the soils decomposes very slowly and can persist for hundreds or even thousands of years (**carbon storage**). **Carbon Pathways** Coastal wetlands tend to be very productive ecosystems—meaning that the plants grow a lot each year. As part of the growth process, plants capture carbon dioxide from the air and convert it to plant parts such as leaves, stems, or roots. This process is called “fixation” or “uptake” of carbon dioxide. Carbon is also lost back to the atmosphere when plants respire (exhale) carbon dioxide, the same way people exhale carbon dioxide. This carbon dioxide is the byproduct of the plants breaking down sugars (i.e. food) and converting it to energy. Some of the carbon that plants capture gets added to soils either via internal transport in the plant or when plant parts, such as leaves and roots, die and become incorporated into the soil. Once carbon is in the soil some of it is respired by microbes and returns to the atmosphere as carbon dioxide. However, some of the carbon stays stored in the soils, often for hundreds or even thousands of years, buried deep underground. **The Importance of Anaerobic Soils** One reason coastal wetlands are particularly good at storing carbon is because the soils are largely anaerobic, which means they lack oxygen. In most coastal wetlands there is usually a thin layer of soil that is oxygenated and above water, but the remainder of the soil is submerged in water. Oxygen diffuses very slowly through water, so saturated (wet) soils in these wetland habitats tend to have little to no oxygen present. Decomposition of organic plant material is much slower when there is no oxygen present, so the carbon present in this plant material remains intact, rather than being broken down by microbes and respired back to the atmosphere. As a result, wetlands are very good carbon sinks (meaning they store a lot of carbon). In summary, coastal wetlands are particularly good at storing carbon because the plants annually sequester (capture) a lot of carbon and then these ecosystems store carbon for long periods of time in their soils.
 **NOAA's Coastal Blue Carbon Efforts** Recent NOAA-supported efforts related to coastal blue carbon include the inclusion of coastal wetlands into the Inventory of U.S. Greenhouse Gas Emissions and Sinks (see Chapter 6). NOAA also sponsored The National Academies of Sciences, Engineering, and Medicine’s project, Developing a Research Agenda for Carbon Dioxide Removal and Reliable Sequestration. NOAA’s coastal blue carbon activities are a collaborative effort across NOAA, including the National Marine Fisheries Service, National Ocean Service, and Oceanic and Atmospheric Research offices. In addition, NOAA partners with Restore America's Estuaries.  2022 Annual Accomplishment Report 2021 Annual Accomplishment Report 2020 Annual Accomplishment Report 2019 Annual Accomplishment Report 2018 Annual Accomplishment Report 2017 Annual Accomplishment Report 2016 Annual Accomplishment Report 2015 Annual Accomplishment Report Peer Reviewed Publications (PDF)  Blue Carbon Fast Facts Protecting Coastal Blue Carbon through Habitat Conservation: NOAA Fisheries Coastal Blue Carbon: NOAA Sea Grant Understanding Blue Carbon   Get **Social** Social
 **Last updated:** 08/16/23 **Author:** NOAA How to cite this article Contact Us


Feedback Provide Feedback
							Contact Us
							Report an error
 Social Instagram Logo/a>


*Science. Service.Stewardship.*
 About NOS About Us
							NOS Program Offices
							Media Inquiries
							Website Acknowledgements
                            Site Index
							Disclaimer
 More Resources Freedom of Information Act
							Accessibility
							Information Quality
							Privacy Policy
							NOS For Employees
							USA.gov
 Department of Commerce
									National Oceanic and Atmospheric Administration (NOAA)
									National Ocean Service