A call to protect carbon in Canada’s ocean floor
In an attempt to halt and reverse the decline of marine biodiversity, Canada has joined commitments to put 25% of its seas into marine protected and conserved areas (MCAs) by 2025 and 30% by 2030. As well as helping animals and plants, the government body charged with managing Canada’s oceans has stated that climate change mitigation is an aim of their MCA network development by protecting marine habitats that naturally store carbon.
Read this open access paper on the FACETS website.
Interest in this “blue carbon” has been focused on salt marshes and seagrass meadows, because, like forests on land, they can directly capture CO2 and store large amounts of carbon within their soils. In comparison to these lush green habitats on our coastlines, the “soils” on the ocean floor may seem empty and unimportant, however they actually contain a unique, diverse and often fragile group of species. Seafloor sediments are also the final point in the marine carbon cycle, and due to covering most of the ocean floor, make up one of the planets largest stores of carbon. There is also increasing evidence that human activities are disrupting the carbon found in seafloor sediments, such as from fishing, energy generation, mining and construction. This new study makes the case for protecting key areas of the seafloor to increase the chance of Canada’s expanding MCA network to provide climate change mitigation benefits.
On a per unit-area basis Canada’s seafloor sediments generally contain much lower amounts of carbon when compared to salt marshes and forests and soils on land. But, certain seafloor areas contain carbon stocks and burial rates similar to, or even higher than these more widely recognised carbon-storing habitats. These hotspots — found in fjords, inlets and bays as well some troughs and channels further offshore — cover only around 2% of the seafloor but are still estimated to contain total amounts of carbon at least ten times that of Canada’s salt marshes and seagrass meadows combined. This presents an opportunity to protect a large amount of carbon in only a small area of Canada’s waters.
By selecting the seafloor carbon hotspots that lie outside current and planned MCAs, a set of priority areas were identified for future research and potential protection. These areas were ranked based on the estimated amount of carbon, the potential vulnerability of the carbon, and the ecological and biological significance of the area. Overall, where nations are developing plans for expanding their MCA networks, the inclusion of key seafloor carbon hotspots would represent a low-risk precautionary policy towards climate change mitigation.
Read the paper — Protection of seabed sediments in Canada’s marine conservation network for potential climate change mitigation co-benefit by Graham Epstein, Susanna D. Fuller, Sophia C. Johannessen, Emily M. Rubidge, Melissa Turner, and Julia K. Baum.