Image of a marshy area surrounding a creek bed

Following the trail of blue carbon in a Georgia salt marsh

Salt marshes provide essential ecosystem services, including sequestering carbon – but the movements of dissolved organic carbon (DOC) in and out of these marshes have not been widely studied. Examining the rate of DOC outwelling in a salt marsh – the amount and speed carbon is moving out of the system – is important for understanding the extent and impact DOC outwelling has on broader coastal carbon cycles.

A recent paper by Christina Codden and Aron Stubbins of Northeastern’s Stubbins Lab tackles this question, examining DOC outwelling patterns at Groves Creek in Georgia. This research primarily took place at the Skidaway Institute of Oceanography. Records of water flux, salt flux, and DOC flux in Groves Creek’s main channel were collected nearly continuously for 16 months and incorporated into this study; making it the first to resolve carbon fluxes through a salt marsh creek at this temporal resolution and extent.

Codden, Stubbins, and co-author Catherine Edwards (Skidaway Institute) detected a decrease in DOC:salt ratio in the summer of 2014 through deviations in the otherwise linear graph between the two. This decrease indicates net DOC outwelling, which the authors posit may be connected to the highly productive summer months.

This work suggests that further research of this type and extent is required to complete the picture of carbon exchange and flux in coastal ecosystems. Codden, the primary author and former PhD candidate in the Stubbins Lab, has completed her doctoral work at Northeastern and is now a Bioinformatics Scientist at ElevateBio.

Marine and Environmental Sciences
Marine Science Center