May 16, 2022


What Is Blue Carbon?

What Is Blue Carbon?

What is blue carbon?

Blue carbon means sequestering carbon dioxide from the atmosphere by the world's oceanic and coastal ecosystems mostly by mangroves, seagrass, microalgae, algae, salt marshes and other plants in wetlands. All of these hold onto carbon, which is called a carbon sink. They sequester carbon at a fast rate for millions of years. Carbon that is stored in coastal soils are at times thousands of years old.

Types of blue carbon ecosystems

Seagrass meadows stabilize sediments and enable habitat biodiversity. Seagrass is a flowering or grassy plant that grows under water. It is not seaweed, which is algae. There can be up to 12 species in one meadow, growing up to 50 meters. The way they grow is based on water quality and light availability and they exist on every continent's shore except Antarctica. They store almost 20 billion tons of organic carbon. Seagrass meadow ecosystems are threatened by sea level rise due to global warming and eutrophication. The earth has faced 1/3 seagrass meadow loss since the 1940's. About 29% of the seagrass blue carbon ecosystems have been lost so far.

Seagrass meadows makeup under .2% of the world's oceans however they sequester about 10% of the carbon sequestered buried in ocean sediment (27.4Tg of carbon per year). 

Mangrove ecosystems are woody halophytes which are plants that grow in saline water. They exist in over 100 regions. They survive in tropical and subtropical waters. Indonesia contains approximately 30% of the world's mangroves. Mangroves in general sequester about 10% of global carbon. Global threats to mangroves include climate disasters from climate change, exploitation of crustaceans and timber, bad water quality, pests, and rising temperatures. Approximately 35% of the mangrove blue carbon ecosystems have been destroyed thus far and continue at a rate of 2% per year. This is a problem because they are the most carbon-rich tropical forests. 

They also benefit societies by supporting fisheries, they filter out contaminants, they provide protection from floods and erosions that happen from storms. Their contribution for a healthy life for people and animals in the subtropics is massive. Mangroves can store up to 10 times more carbon than forests that are on land.

Marshes survive on arctic to subtropic global coastlines. They produce biomass below ground and sequester carbon because of the high rates of organic sedimentation. Marshes provide for coastal habitats and protect from storm surges and flooding. They are in danger of human destruction and sea level rise. Marshes store approximately 95% of their CO2 in the soils. 

They help maintain water quality in their regions because of their ability to filter out contaminants. Since they provide a healthy environment for the entire life cycle of marine life, they also provide a source of fisheries that benefit people. 

Microalgae and kelp forests are blue carbon ecosystems that include tropical and temperate red, blue, green, and brown algae. Seaweed is a type of algae. Globally, microalgae sequesters 381 billion pounds of carbon per year. Carbon stored in microalgae tissue is carried away by currents where it is stored in sediments of the continental shelf and ocean.

In the following graph from Sustainable Travel International, see the amount of CO2 that blue carbon ecosystems store in comparison with other ecosystems:

Related content

To learn about how you can reduce carbon emissions please read our following content:

• Article: 13 Ways to Reduce Your Carbon Footprint
• Article: Carbon Emissions in the Atmosphere and the Methods of Abating Emissions
• Article: Carbon Emissions and Mitigation Strategies

Why is blue carbon important?

  • Since oceans cover about 70% of the world, they are the most likely to remove and store carbon for millenia. They are a natural carbon sink, sequestering most of that carbon in soil and sediments. 
  • "The oceans contain about 50 times more CO2 than the atmosphere and 19 times more than the land biosphere," according to the Water Encyclopedia. 
  • CO2 moves into and out of oceans quickly which is important for regulating the amount of it in the atmosphere.
  • Blue carbon ecosystems provide food and shelter for sea creatures which maintain a healthy and necessary balance for marine ecosystems. Dugongs eat about 88 pounds of seagrass a day and use it for shelter and adult green turtles eat about 4.5 pounds of seagrass in a day. Saving the endangered dugongs or "sea cows" significantly helps mitigate global warming.
  • When blue carbon ecosystems are damaged or destroyed, they emit carbon into the oceans and atmosphere which they had been storing for centuries. Blue carbon ecosystem degradation emits 1.02 billion metric tons of CO2 into the atmosphere every year.

What can be done?

Ensuring the safety, equilibrium, and health of blue carbon ecosystems is the key to effective carbon sequestration that is not re-emit in the future. 

With coastal management strategies to protect blue carbon ecosystems, carbon mitigation can be achieved more efficiently in addition to the benefits of the ecosystem itself. Measurements from blue carbon in these ecosystems are now becoming standardized for accuracy. There are also protocols of methods that are becoming standardized to preserve the ecosystems.

Organizations like The Blue Carbon Initiative work to protect and restore coastal ecosystems especially for matters regarding climate change. They also work with a science research based group Blue Carbon Scientific Working Group and and a policy group International Blue Carbon Policy Working Group to be able to achieve their Blue Carbon Activities goals. 

Final takeaways

There is strong motivation all over the world to preserve and protect blue carbon ecosystems. Organizations are accumulating more members to restore blue carbon ecosystems as well. Moreover, adding blue carbon ecosystems into the voluntary carbon markets and trading schemes will provide additional project funding to sequester carbon and in turn, preserve and restore the blue carbon ecosystems. 

Net0 emissions management platform helps organizations measure, reduce, offset, and report their emissions, and get carbon neutral certified, fast. Book a free call with a Net0 expert to experience the platform and how it can help you. Since Net0 offers a wide range of offsetting projects that are verified around the globe, blue carbon and ocean preservation are some of the projects your organization can choose to contribute to as we move towards net zero. 

Cover image source: Great Barrier Reef Foundation

Written by:

Request a demo of Net0 platform

Talk to us to learn more about making your business carbon neutral.
Request a demo

Reimagine Sustainability
with AI

Capitalize on the economic opportunities of sustainability with Net0's emissions management software.

Schedule a demo
Net0 Interface