Salt Marshes Store Carbon

Perhaps one of the most surprising things about salt marshes is the salt marsh carbon aspect. Salt marshes are really good at storing harmful carbon.  Even more surprising is that they are much better at it than forests! So they are helping to protect the climate.

It is the plants that do the work.  They take in carbon from the air and sea and sequester it underground.  As more mud sweeps in on the tide, it buries the carbon deeper and deeper.   So it is difficult for it to escape back into the environment.

This is demonstrated in the figure below. It shows that tropical forests store more carbon in the living tree than in the ground. If the tree dies or is cut down the carbon is released back into the environment. By contrast mangroves store much more carbon underground. You can see that salt marshes also do a good job at storing a lot of carbon underground and very little above.

Figure: 1 – Mean carbon storage in the above and below ground biomass in vegetated coastal ecosystems vs. terrestrial forests. Source: Howard et al. (2014) see footnote 1 below for full source.

Blue carbon

Blue carbon is the carbon stored by tidal and marine ecosystems. Mangroves and sea grass meadows are other blue carbon ecosystems.

Figure 2: comparison of the carbon burial rates per year of terrestrial and the blue carbon of coastal habitats. Source: Mcleod et al. (2011) see footnote 2 below for full source.

This also clearly demonstrates the relative carbon storage of different ecosystems. Blue carbon ecosystems, like our salt marshes, are hugely important in helping to protect the climate.

Salt Marshes – Coastal Superheroes

Watch Scott’s video to find out more.

Further reading about Salt Marsh Carbon:

• This is a very interesting feature about Steart Marshes and blue carbon: https://features.wwt.org.uk/blue-carbon/index.html
• This is a great link for all things blue carbon: https://www.thebluecarboninitiative.org

Find more surprising facts about our salt marshes

Footnotes with full sources for Figures 1 and 2:

1. Howard, J., Hoyt, S., Isensee, K., Telszewski, M., Pidgeon, E. (eds.) (2014). Coastal blue Carbon: Methods for assessing carbon stocks and emissions factors in mangroves, tidal salt marshes, and seagrasses. Conservation International, Intergovernmental Oceanographic Commission of UNESCO, International Union for Conservation of Nature. Arlington, Virginia, USA. Downloadable at: https://www.thebluecarboninitiative.org/manual
2. Mcleod, E., Chmura, G. L., Bouillon, S., Salm, R, Bjork, M., Duarte, C. M., … Silliman, J. A. (2011). A blueprint for bluecarbon: Toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2. Frontiers in Ecology and the Environment 9, 552–560.