Temperate fiords are known hotspots for carbon burial. Initial estimates are that the amount of carbon buried in the deepest parts of Fiordland, New Zealand, is equivalent to 10-20% of the country’s greenhouse gas emissions. These high rates of carbon burial are driven by large inputs of organic carbon into the fiords from the surrounding rainforest, retention of organic carbon in the fiords, and an anoxic receiving environment in the deep fiord basins.
This presentation will provide the latest estimates of carbon burial rates in the Fiordland Marine Area, informed by geochemical analyses of seafloor sediments throughout the region. It will then focus on the vulnerability of this significant carbon sink to human impacts including forest and water management and changing climate and ocean conditions. Some of these impacts, if shown to have reduced carbon sequestration, provide the potential for additionality. Our findings will be discussed in the broader context of how marine carbon sequestration is (or rather is not) accounted for in greenhouse gas reporting, and will include recommendations for how protection and restoration of the marine environment could be better included in our climate change response.