Carbon storing capacity of North Pacific Eelgrass

What is it about?

Coastal wetlands have been hailed for their high capacity to sequester (or store) carbon. The stored carbon is called “blue carbon,” and this capacity is being seen as a potential method to mitigate the effects of climate change. There are three types of coastal wetlands: tidal marshes, tidal forests, and seagrass meadows. Among these, the potential of seagrass meadows to bury carbon has not been studied as much as that of the other types. The authors of this study look at the carbon sequestration capacity of Zostera marina, a common eelgrass species found in the northern hemisphere. Despite being abundant in the Pacific Northwest, Z. marina has been understudied. In this paper, the authors aim to find out the storage rates and carbon stocks of one of the biggest temperate eelgrass meadows in the North American Pacific coast.

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Photo by Benjamin L. Jones on Unsplash

Photo by Benjamin L. Jones on Unsplash

Why is it important?

Carbon storage by seagrass is the least studied among all the types of coastal wetlands. Within the limited available literature, tropical and subtropical seagrass species dominate the studies on carbon sequestration. This is despite that Z. marina is the most common seagrass species in the northern hemisphere. With an area spanning 3800 ha, the temperate meadow in the Padilla Bay in Washington is the largest continuous eelgrass growth. This huge underwater grassland could potentially store large amounts of carbon. Thus, the storage ability of Z. marina must be determined to allocate appropriate carbon offset credits within the economics of blue carbon. KEY TAKEAWAY: Though a large meadow of Z. marina may store a lot of carbon, the species has a low ability to store carbon owing to its specific habitat needs. The results of this study must be considered before allocating many carbon offset credits to eelgrass meadows and unintentionally raising the net carbon emissions. Future studies should look at measuring the carbon storage rates of other Z. marina meadows.