Prior to the Oceans 2024 Conference, researchers and policy makers participated in a workshop facilitated by the Buchwald Lab at Dalhousie University’s Department of Oceanography and the Ocean Frontier Institute, and supported by startup firm Coastal Carbon, LLC. The goal of the workshop was to help develop a methodology for macroalgae (seaweed)-based carbon dioxide removal (CDR). Experts from the Transforming Climate Action project, the Ocean Frontier Institute (OFI), Fisheries and Oceans Canada, Dalhousie University, Memorial University, Université du Québec à Rimouski, Université Laval, and additional international expertise, gathered to discuss this scientific technique.
Macroalgae-based CDR is the conversion of atmospheric CO2 into organic carbon sequestered in ocean sediments. Seaweed, a class of photosynthetic organisms, creates biomass from CO2, and throughout its life cycle, releases detritus that naturally sinks or is otherwise transported into the deep sea. Through aquaculture and restoration of natural seaweed beds, we can increase the flux of organic carbon sequestered in the ocean.
Globally, it is estimated that between 10-15 per cent of total carbon captured from existing seaweed forests is sequestered in the deep ocean for longer than a century – timescales sufficient for present CDR targets. As sustainability and conservation goals currently include the expansion of seaweed aquaculture and reforestation, the additional promise of carbon sequestration by seaweed cultivation is being actively explored.
To successfully implement this type of project, the framework, measurements, and monitoring systems need to be established to verify that carbon was sequestered. It is imperative to develop these methodologies alongside domain experts and listen to inputs from law and policymakers to adequately consider scaling and deployment of these technologies within existing market-based frameworks.
OFI Industry Postdoctoral Fellow Donald Martocello and supervisor Professor Carolyn Buchwald led the workshop and reviewed a draft document they had prepared. Specific techniques and modeling schemes were reviewed to determine the best strategies to deploy seaweed-based environmental and carbon credits. Ultimately, it emerged that growth-cycle based seaweed CDR remains a viable strategy forward, but requires thorough scientific validation. Martocello and Buchwald are presently synthesizing the feedback and hope to publish a final version of the methodology by year’s end to support the development of ethical and responsible seaweed projects.
Immediately following the workshop, Laura Meyer, LL.M., Stakeholder Coordination Officer, IOC-UNESCO, led a seminar about the role of international law in shaping ocean-based CDR technologies. The focus was on the potential role of the recently adopted Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas beyond National Jurisdiction (BBNJ Agreement). Seminar participants discussed hurdles and strategies for developing international agreements to facilitate the development of ocean-based CDR projects, with macroalgae CDR prominently featured as seaweed aquaculture is a crucial part of developing circular “blue economies” – a key goal shared by numerous maritime nation states, including Canada.
OFI recognizes the importance of collaboration in driving ocean innovation. This workshop exemplifies how OFI can support bringing together leading scientific researchers with industry and policymakers to promote and advance initiatives at the ocean frontier.
