Kira Krumhansl1, Melisa Wong1, Manon Picard1, Meredith Fraser1, Carrie-Ellen Gabriel1, Yongsheng Wu1, Wendy Gentleman2, Kumiko Azetsu-Scott1
1Fisheries and Oceans Canada, Canada - 2Dalhousie University, Canada
Coastal vegetated ecosystems are recognized for their role in cycling and storing carbon in the world’s oceans (i.e. blue carbon), however estimates of carbon fluxes and sequestration by these habitats are associated with high uncertainty. This is largely due to the fact that existing estimates have been generated from coarse global studies or are a compilation of studies conducted on disparate systems and species. We developed the first detailed carbon budget for kelp and seagrass ecosystems in Nova Scotia, Canada through field data collection, experiments, modeling, and data extraction from published literature for our species and region. Our results reveal that the productivity and standing carbon stock contained in kelp forests in our region exceeds that of seagrass beds due to higher predicted habitat area and per unit area rates of net primary production. We also estimate that the quantity of carbon potentially sequestered through the production and export of dissolved organic carbon (DOC) by kelps and seagrasses is higher than through the local burial and export of particulate organic carbon (POC). This is due to high production and export rates of DOC, particularly by kelps, paired with low export rates of kelp and seagrass POC to the shelf break ( 0% for kelp, 5% for seagrass). We estimate that the majority of POC remains at depths <100 m where most of it is likely remineralized. These carbon budgets reduce uncertainty in our knowledge of the contribution of nearshore vegetated habitats in our region to carbon sequestration, and contrast the coarse resolution global budgets generated previously, demonstrating the importance of detailed regional study for improving our knowledge of blue carbon.
Biography
Kira Krumhansl completed her PhD in Biology at Dalhousie University, where she studied carbon cycling and trophic dynamics in kelp forests in Nova Scotia Canada. She did postdoctoral research at Simon Fraser University examining climate change and harvest impacts on giant kelp forests. She has worked at Fisheries and Oceans Canada since 2016, where she conducts research in nearshore ecology with a focus on climate change impacts and carbon cycling in kelp forests and seagrass beds.