Exploring Carbon Dynamics in Taiwan's Qigu Lagoon: The Balance Between Carbon Burial and Methane Emissions

Blue Carbon Ecosystems (BCEs) play a crucial role in carbon sequestration and climate change mitigation. However, their carbon cycle dynamics, particularly under changing environmental conditions, remain insufficiently understood. This study investigates the Qigu lagoon ecosystem, a representative BCE along Taiwan's southwestern coast. Adjacent to mangrove forests, the lagoon harbors rich biodiversity and holds substantial carbon storage potential but faces increasing threats from global climate change and intensified human activities. To address these challenges, we conducted integrated field sampling and laboratory analyses to examine the biogeochemical processes governing carbon cycling in the Qigu lagoon. Sediment cores were collected from multiple locations across the lagoon and analyzed for dissolved methane concentrations, total alkalinity, dissolved ions, and nutrient levels. These measurements aim to quantify sedimentary carbon burial rates, assess greenhouse gas emissions, and evaluate nutrient cycling within the ecosystem. Preliminary results indicate that, while the lagoon effectively sequesters organic matter in its sediments, it simultaneously emits significant amounts of methane (CH₄), a potent greenhouse gas. This discovery raises important questions about whether methane emissions from wetlands—traditionally regarded as natural carbon sinks—may substantially offset the carbon burial and absorption capacity of marine blue carbon systems. Understanding the balance between carbon sequestration and greenhouse gas emissions is critical for accurately evaluating the climate mitigation potential of BCEs. Findings from this study will provide valuable insights for the conservation and sustainable management of coastal ecosystems, contributing to global efforts in combating climate change.