The underwater kelp forests that line Canada's coastlines may offer an untapped option for natural climate solutions, a new study led by University of Victoria shows, in the first national assessment of the country's kelp ecosystems.
The research team set out to estimate how much carbon the ecosystems might be capturing and storing in the ocean, and whether that carbon stays out of the atmosphere long enough to be considered a natural climate solution. Using aerial and satellite maps of kelp occurrences, and measurements of kelp productivity, and coastal ocean transport models, the team built a national kelp forest database to take stock of the carbon that gets absorbed, stored, and exported from Canada's kelp forests to natural carbon sinks in the ocean.
"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 and UVic postdoctoral research fellow with Blue Carbon Canada.
"At the same time, the data gaps have made it impossible to know their full potential. 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 successfully capture carbon, storing it within seafloor sediments or exporting it to the deep ocean, and thus keeping it out of the atmosphere long-term. The team's new research suggests Canadian kelp forests may capture and export between 40,000 and 400,000 metric tons of carbon to the deep ocean per year. A promising number, but only if that carbon stays in the ocean long-term.
There are still a lot of unknowns about where the carbon captured by kelp forests ends up in the ecosystem. "We need more strategic monitoring and mapping of these systems to understand their full potential," adds McHenry.
"Despite gaps in our understanding of kelps' role in carbon drawdown, it should not stop us from protecting and restoring these ecosystems because they are vulnerable to climate change," says Julia Baum, UVic professor of biology and principal investigator of Blue Carbon Canada.
"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 Baum. "It's vital we protect these ecosystems for all these reasons."
Further research is needed to understand the risks and benefits of relying on kelp-based solutions, Baum adds, as her team looks at furthering the knowledge base while stemming further kelp ecosystem loss.
The research, which is published in npj Ocean Sustainability and includes a research team of roughly 20 co-authors from 14 different institutions in Canada, US and Australia, is supported by funded by Fisheries and Oceans Canada and the Natural Sciences and Engineering Research Council of Canada.
