New national blueprint for kelp forests as blue carbon
June 25, 2025
The underwater kelp forests that line Canada’s vast coastlines may offer an untapped natural climate solution, according to a new national study led by ßÉßɱ¬ÁÏ researchers. Among the study’s co-authors are UVic Geography professor Maycira Costa and postdoctoral researcher Alejandra Mora Soto, who contributed remotely sensed data and analysis through UVic Geography’s .
This groundbreaking project represents the first nationwide assessment of kelp forest carbon capture across Canada, drawing on satellite and aerial imagery, productivity estimates, and coastal ocean transport models. The interdisciplinary team built a national kelp forest database to take stock of how much carbon is absorbed, stored, and exported from Canada’s coastal ecosystems into long-term ocean carbon sinks.
“Kelp forests are increasingly being positioned as a source of natural climate solutions because they could help us tackle climate change by storing more carbon in the ocean,” says Jennifer McHenry, lead investigator of the study and a UVic postdoctoral research fellow with .
“At the same time, the data gaps have made it impossible to know their full potential,” adds McHenry. “Our study aims to address this gap by offering a blueprint for Canada and other countries to follow when assessing their kelp forests.”
Kelp forests have been shown to capture carbon and either store it in seafloor sediments or export it to the deep ocean, potentially keeping it out of the atmosphere long-term. The team’s analysis estimates that Canadian kelp forests may capture and export between 40,000 and 400,000 metric tons of carbon to the deep ocean annually—an encouraging figure, contingent on the carbon remaining stored at depth.
Pathways for sequestration of macroalgae carbon into the deep sea. Figure adapted from Krause-Jensen and Duarte, 2016. Property of the International Science Council.
There are still a lot of unknowns about where the carbon captured by kelp forests ends up in the ecosystem, explains McHenry. “We need more strategic monitoring and mapping of these systems to understand their full potential.”
For Costa, who leads long-standing efforts to map marine vegetation from space, this study reinforces the value of long-term investment in remote sensing and field-calibrated monitoring. The research equally underscores the critical importance of protecting kelp ecosystems.
“Kelp forests have immense value, not only because they capture carbon, but also because they harbour considerable coastal biodiversity, support local fisheries, and provide a slew of other ecosystem services,” says Julia Baum, UVic biology professor and principal investigator of Blue Carbon Canada. “It’s vital we protect these ecosystems for all these reasons.”
Published in npj Ocean Sustainability, the research involved roughly 20 co-authors from 14 institutions in Canada, the United States, and Australia. The project was supported by Fisheries and Oceans Canada and the Natural Sciences and Engineering Research Council of Canada.
This story was initially published in UVic News and written by marketing and communications manager Jennifer Kwan. It has been modified to add relevance to the UVic Geography department.