Alaska kelp farm CO2 study shows mixed results: one site absorbed carbon, another released it

A University of Alaska Fairbanks study measured carbon dioxide levels at two kelp farms in the Gulf of Alaska during the 2023-2024 growing season. The results were mixed. One farm in Windy Bay near Cordova slightly reduced local CO2, while another in Kalsin Bay on Kodiak Island added more CO2 to the environment. Factors like seaweed type, tide patterns, and marine growth on equipment influenced the outcomes. The study, published in Ocean Science, is the first to measure marine carbon dioxide removal in Alaska waters. Researchers installed sensors to track ocean chemistry, temperature, and oxygen levels hourly. They found that kelp farms can flip between absorbing and releasing CO2 depending on sunlight, time of day, and tidal flushing. The lead researcher noted that while the farms are not harmful, their climate benefits should not be overstated. This research highlights the complexity of using seaweed for carbon removal. It suggests that location-specific conditions matter greatly for mCDR projects. The findings are relevant for carbon markets and climate policy that consider ocean-based solutions, as they show that assumptions about kelp's carbon absorption capacity need careful validation.