While there are some more well-known solutions to carbon dioxide removal, there are others that may surprise you. On Wednesday, Oct. 16, the National Seaweed Hub Webinar Series concluded with “The Potential of Seaweeds for Carbon Dioxide Removal and Sequestration: Challenges in Monitoring, Reporting, and Verification,” showcasing the role of seaweed in the process.
Professor Catriona Hurd, a seaweed eco-phycologist, led the virtual event from the University of Tasmania. Hurd started the webinar by providing an outline, which included an introduction to seaweeds of cold temperate systems, the need for carbon dioxide removal and the reality of the challenges brought along with this idea.
Hurd mentioned seaweed as “crucial primary producers of coastal systems” as they have many needs, including food for higher trophic levels, biodiversity enhancement and carbon and nitrogen cycling. There have also been losses of seaweed due to climate change. For example, Macrocystis pyrifera, better known as giant kelp, is a kelp known for how quickly it grows and can provide shelter for sea life. This kelp is an endangered species, and according to Hurd, 95 percent of it is lost and sensitive to climate change.
The webinar then makes its path to a more crucial point: the need for carbon dioxide removal. Hurd provides vital statistics, including that humans emit 37 billion metric tons (Gt) of carbon dioxide (CO2) annually. She explained that if humans reduce emissions by 50 percent, the planet would still need carbon dioxide removal to remove, and securely store, 4-5 Gt of carbon annually. This brings in the importance of seaweed in carbon dioxide removal. Seaweed has now been seen as a possible marine carbon dioxide removal method.
However, misinformation has also spread about seaweed and their potential aid in carbon dioxide removal. Hurd showed examples in articles such as “these carbon-capturing robotic seaweed farms are like planting forests in the ocean.” This is an example of misinformation because seaweed has potential benefits, but aren’t comprehensive solutions. Additionally, it makes the process seem much easier than it really is. Forests and seaweed farms operate very differently and can’t compare. It creates unrealistic expectations of this approach.
For these reasons, Dr. Hurd provided attendees with the goals of the National Seaweed Hub Webinar Series: educating others on the truth and what it really would take to regulate carbon dioxide removal, as well as the complexities of monitoring, reporting and verifying seaweed carbon, which has multiple steps.
Hurd’s first step stated, “track the seaweed carbon from the original seaweed bed and determine the storage time.” By tracking both the carbon uptake and the storage time, researchers can better understand the effectiveness of seaweed as a tool for carbon capture. Step two stated, “track the seawater with the CO2 deficit from the original seaweed bed for weeks to months to determine CO2 drawdown (CO2 equilibrium),” which has the same effect as step one. Step three stated, “quantify steps one and two and link back to the original seaweed bed.” Researchers can then gain an understanding of the carbon dynamics associated with the area.
Ending the presentation, Hurd prepared a slide that told us other ways seaweed can help the environment, which listed the following: “methane emissions reduction for ruminants (cows and sheep), substitution for oil-based products (bioplastics and seaweed bricks), food security, novel products, nutrient mitigation of coastal regions and biodiversity enhancement (natural systems).”
Hurd then answered questions from the audience to conclude the webinar officially. Among those questions was, “can you talk a little more about how farmed seaweeds can help reduce methane emissions?”
Hurd told the attendees about a seaweed grown in Australia and Japan called asparagopsis that has chemicals. Feeding it to animals such as cows and sheep stops them from burping and farting, ultimately reducing methane emissions from livestock.