To a viewer, it might look like he’s playing in the mud, but he’s actually investigating how important coastal ecosystems are to Canada’s fight against climate change. Pellatt, a coastal ecologist with Parks Canada, led a team that was part of an international effort to study and conserve coastal systems this year. The joint initiative involves Canada, the US and Mexico studying “blue carbon” — the carbon stored in marine ecosystems. “About a decade ago, there was interest in how these natural systems interact in the carbon cycle and what value they might have in mitigating climate change,” Pellatt told CTVNews.ca in a phone interview. It is well known that plants absorb the harmful greenhouse gas (GHG) carbon dioxide as part of the process of photosynthesis, which creates food for vegetation by combing sunlight and water. What the scientists wanted to understand was how the coastal plants and soil found in mangroves, tidal salt marshes and grasslands absorbed carbon and how efficiently these ecosystems were.
WHAT IS BLUE CARB?
It is the term scientists and researchers use to describe the carbon sequestered and stored in coastal and marine ecosystems. All water-based ecosystems, such as wetlands, peatlands and lakes, absorb carbon but at a slower rate than coastal systems. Researchers have long understood that plants absorb carbon through photosynthesis, but they wanted to understand how to harness the carbon sequestration powers of the natural world. As Pellatt walks around Grice Bay, a popular starting point for visitors to British Columbia’s Pacific Rim National Park, he focuses on the plants and soil at his feet. The site chosen for the survey is a tidal eelgrass salt marsh on Vancouver Island. “The work we’ve started with focuses on tidal salt marshes and seagrass meadows, mainly because those are where we’ve got a good handle on their ability to store carbon,” Pellatt said.
Canada has the longest coastline in the world, spanning 243,042 km, including mainland and offshore island shores. With such a vast coastline, scientists believe there is much more to understand about these precious ecosystems. By coining the term blue carbon and understanding how nature absorbs and stores CO2, scientists and governments can work to use Canada’s coastal ecosystems to their advantage in the fight against climate change.
SO WHY IS THIS IMPORTANT?
Understanding how much carbon coastal ecosystems absorb and store carbon helps Canadians understand how to play a role in conservation. Canada is committed to reducing emissions by 40 to 45 percent from 2005 levels by 2030. There is a further goal for Canada to achieve net zero emissions by 2050. The most recent figures from 2020 show that Canada emitted 672 megatons of carbon dioxide into the atmosphere, down from 738 megatons in 2019. To meet the current 2030 target, Canada needs to be between 296 megatons and 333 megatons of GHG emissions. If coastal ecosystems are destroyed by natural disasters or humans, carbon buried underground is released into the atmosphere. The Blue Carbon Initiative, an organization focused on saving coastal marine habitats, estimates that when these ecosystems are degraded or destroyed up to 1.02 billion tons of CO2 are released annually worldwide. Not only is carbon released, but the ecosystem no longer absorbs CO2 after the disaster. A research article published in Science Advances in June 2021 titled “Natural Climate Solutions for Canada” explains that blue carbon ecosystems can mitigate the release of 1.7 million tonnes of CO2 by the year 2030, equivalent to 3.4 million barrels of oil. That’s why the federal government invested in a three-year, $1.59 million Blue Carbon Canada collaborative program with a team of researchers and policy experts from Parks Canada and Fisheries and Oceans Canada, along with other conservation organizations. The research will help determine where the country’s blue carbon ecosystems exist, their mitigation capacity and how they adapt to climate change scenarios. The research paper explains that when ecosystems are disturbed, they are unable to absorb as much carbon. When restoration is involved, ecosystems will recover but not as efficiently. This shows Canadians and governments that preserving coastal ecosystems is extremely valuable in helping Canada meet its 2030 GHG emissions targets. “These systems serve as this important, natural barrier that often protects cities and these communities, and that’s what we settled on,” Pellatt said. “It’s really important to understand these carbon dynamics and biodiversity aspects, especially when we need to respond and adapt to climate change.” Coastal ecosystems help support fishing industries by providing habitat for wildlife and act as a barrier to land from floods and storms.
WHAT SCIENTISTS DISCOVERED IN THE MUD
Ecosystems along coastal areas absorb carbon at a faster rate than forests, despite the fact that the total area is much smaller than Canada’s woody ecosystems. Part of the reason is the storage capacity of trees versus coastal plants. Where trees store CO2 in their leaves and underground to feed themselves, plants in tidal salt marshes or mangroves have the ability to store carbon for thousands of years in the bottom sediment, which remains in ecosystems for centuries. Gail Chmura is a professor in the geography department at McGill University specializing in biogeography, paleoecology and wetland dynamics. For years, Chmura has studied the complex ecosystems in the Bay of Fundy along the New Brunswick coast. “The muddy water comes in, it sits there a little bit because it’s a basin … and all the mud settles and the water drains out,” he says of the tide coming into the Bay of Fundy. “We found in about six years at one site, there was almost a meter of sludge that had built up, and that sludge was actually trapping a lot of carbon.” In a review published in the Ecology Society of America in January 2011 titled “A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2,” researchers compiled studies of coastal ecosystems and they described where the blue carbon is stored around. The world. Beneath the top layer of plants, oyster shells and dead wood, CO2 can be found in the roots of sea grass. From samples deep within the soil, the researchers found that blue carbon is captured in the short term and stored in the long term. In one case in Portlligat, Spain, researchers found coal deposits more than 10 meters thick and more than 6,000 years old. Along the coast of Canada, researchers are confident the findings are similar, showing carbon stored deep in the soil for thousands of years.
SALT VS FRESHWATER ECOSYSTEMS
Over the years, scientists have discovered that ecosystems exposed to saltwater absorb more carbon dioxide than freshwater wetlands. So why; According to a report on the Environment and Climate Change Canada website created by Chmura, wet conditions caused by regular coastal flooding are a reason for efficient carbon sequestration and storage. “When you lose one of these ecosystems … the organic matter can decompose pretty quickly,” Chmura said. “Unlike when it has saturated soil, you have very, very slow decay.” If wetlands dry out, plant matter begins to decompose releasing methane into the atmosphere along with CO2. Both GHG emissions are harmful, but wetland destruction contributes to methane pollution, which is 25 times more potent than carbon dioxide over a 100-year period, depleting the ozone layer more. Salt water systems do not emit as much methane. Although both natural ecosystems store greenhouse gas emissions and both need to be preserved, researchers have further questions about the coast. Through their research in Grice Bay, Pellatt and his team found that northern coastal ecosystems have different carbon storage capacities than those in the south. “Most of the carbon isn’t stored in plants, it’s stored in the sediment because of the way plants grow,” Pellatt said. “If we think about eelgrass in these northern systems, they tend to be smaller, their roots tend to be shallower in the sediments, and therefore, they just don’t have that ability to store as much carbon over the long term.” The eel layers of BC appear to store “significantly” less carbon than the global average for this ecosystem, but the province’s salt marshes are on par with the global scale. Like previous research, Pellatt’s team determined that BC’s salt marshes capture and store more carbon than the province’s boreal forest. “When we understand what’s in these salt marshes, the turtle systems, the peat systems and the forests, it all shows value beyond resource value. It shows the value of keeping these systems intact,” Pellatt said.
