NEWS RELEASE

NEWS RELEASE

The salt marshes, mud flats and eel grass meadows of temperate river estuaries are more effective than young coastal forests at capturing and storing carbon dioxide and may sequester this greenhouse gas for centuries, if not millennia, according to researchers from the University of Victoria (UVic). The amount of carbon sequestered by the Cowichan estuary salt marshes on Vancouver Island is roughly double that of an actively growing 20-year-old Pacific Northwest forest of the same area, reports [a study](https://www.frontiersin.org/articles/10.3389/fmars.2022.857586/full#B28) published in the journal *Frontiers in Marine Science*. The research was supported by UVic, Ocean Networks Canada, and the Cowichan Estuary Restoration and Conservation Association. So-called blue carbon – carbon dioxide (CO₂) captured from the atmosphere by marine plants and algae – collects as organic debris in estuary sediments where low-oxygen conditions prevent their decomposition. “Oxygen is depleted very quickly from the surface of the sediment due to aerobic microbial processes. This prevents buried organic matter from being remineralized back into CO₂, preventing it from returning to the atmosphere,” said lead author Tristan Douglas, a UVic graduate student in the School of Earth and Ocean Sciences, who spent two years analyzing the physical and chemical properties of sediment cores collected from the Cowichan Estuary. That makes undisturbed estuaries a potent passive carbon storage system with the global potential to capture and store greenhouse gas (GHG) emissions at the gigatonne scale. Intertidal ecosystems – especially those in the tropics – can be 20 to 60 times more effective than forests at capturing and storing carbon dioxide. However, compromised estuaries can and do release carbon on a similar scale, the authors warn. Plant species like salt marsh grasses and sedges, mangrove forests and seagrasses are particularly efficient natural carbon sinks. They capture and store up to 70 per cent of the organic carbon resident in marine systems, despite only occupying 0.2 per cent of the ocean surface. The report shows that the carbon sink capacity of the 466-hectare Cowichan-Koksilah Estuary has been compromised by industrial and agricultural activity since the area was settled by European colonists. Eel grass on about 129 hectares of the intertidal zone has been disturbed by log handling and storage, while about 100 hectares of salt marsh was drained for farming and cattle pasture. This has reduced its natural capacity to sequester carbon by about 30 per cent, equivalent to putting 53 typical gasoline-powered motor vehicles back on the road.

NEWS RELEASE Newly published research by scientists with the Solid Carbon project shows that carbon dioxide (CO₂) taken from the atmosphere and injected into the deep subseafloor off Vancouver Island may turn into solid rock in about 25 years. Solid Carbon, an international research team led by Ocean Networks Canada (ONC), a University of Victoria initiative, and funded by a PICS Theme Partnership grant from the Pacific Institute for Climate Solutions, hosted and led by UVic, is investigating how to permanently and safely sequester CO₂ as rock in the ocean floor. The project is part of the emerging field of negative emissions technologies—climate solutions that reduce the amount of carbon in the earth’s atmosphere.

NEWS RELEASE Injecting carbon dioxide (CO₂) into ocean basalt has almost no risk of triggering any seismic activity such as earthquakes or fault slip according to new research from [Solid Carbon](https://solidcarbon.ca/), a promising climate change mitigation project for reducing the amount of carbon in the Earth’s atmosphere. Advanced computer modelling by scientists with the Solid Carbon team shows injecting CO₂ under the Cascadia Basin has less than 1 percent chance of causing fault slip. Solid Carbon, an international research team led by Ocean Networks Canada (ONC), a University of Victoria (UVic) initiative, and funded by the Pacific Institute for Climate Solutions, is investigating how to permanently and safely store CO₂ below the ocean floor. The goal is to capture CO₂ from the atmosphere and inject it into young (less than 15 million years old) porous basalt rock, such as that found in the Cascadia Basin off the west coast of Canada, where it would interact with minerals, transforming into carbonate rock.

NEWS RELEASE Massive volcanic carbon dioxide (CO₂) emissions contributing to an extreme global ocean deoxygenation event over 120 million years ago has modern day implications for understanding a climate warming “tipping point,” according to new research published in *Nature* this week, led by a scientist at Ocean Networks Canada, a University of Victoria initiative. The paper titled [*A climate threshold for ocean deoxygenation during the Early Cretaceous*](https://www.nature.com/articles/s41586-024-07876-1) reconstructs historical Earth-system processes to establish a climate warming threshold that when crossed, leads to widespread and persistent ocean deoxygenation. Led by Kohen Bauer, director of science at ONC, the research team reconstructed environmental conditions using rock samples from the University of Milan archive. The sedimentary rocks studied date back between 115 and 130 million years and were originally deposited in the ancient oceans. By measuring the geochemical composition of the rocks, the team produced a unique high-resolution record of environmental change. “Our work shows that massive volcanic carbon emissions led to a rapid increase in atmospheric CO₂ concentrations and the crossing of a climate-warming threshold, or tipping point, that resulted in widespread ocean deoxygenation. Following this, Earth’s climate system then remained in a warmed state for over two million years,” says Bauer, who began the work while at Hong Kong University’s Department of Earth Sciences and completed it at UVic.