In a recent study published in the journal AGU Advances, researchers from UC Santa Barbara have proposed that anoxic marine basins could be a viable option for large-scale carbon sequestration in the deep ocean, with minimal negative impacts on marine life. As efforts to reduce atmospheric carbon levels intensify, the idea of sending plant biomass to oxygen-free zones on the seafloor is gaining traction as a potential solution. This approach aims to prevent the release of CO2 and methane into the atmosphere by locking carbon away in the deep ocean for extended periods, thus contributing to global climate goals.
While the concept of sinking plant biomass is not new, it comes with uncertainties and potential risks. Questions arise about the impact of introducing large amounts of plant material on the chemistry and ecology of the target areas, and the possible escape of decomposition byproducts into sensitive marine habitats. Additionally, the risk of carbon resurfacing and being released back into the atmosphere must be carefully considered. Identifying the least detrimental approach to this idea is crucial to avoid further harm to fragile ocean ecosystems and to achieve effective carbon sequestration goals.
Anoxic marine basins have emerged as promising locations for carbon storage due to their unique characteristics. These basins are deep and isolated from oxygen-rich currents, making them inhospitable to animal life and ideal for the preservation of plant matter. The researchers focused on three specific basins – the Black Sea, the Cariaco Basin, and the Orca Basin – to assess their potential for biomass storage. Among these, the Black Sea stood out as the most suitable option due to its depth, isolation, and capacity for accommodating biomass at a significant scale relevant to global climate efforts.
The Black Sea, with its increasing anoxia resulting from human activities, offers a promising environment for carbon sequestration. The Cariaco Basin, although similar in chemical properties to the Black Sea, experiences faster water turnover. In contrast, the hypersaline Orca Basin presents unique challenges and opportunities due to its high salt concentration and density differences. The researchers highlighted the potential of locking carbon into the hypersaline layer of the Orca Basin, once it passes the interface between normal seawater and brine.
The researchers’ findings underscore the potential of anoxic marine basins, particularly the Black Sea, as a significant contributor to climate mitigation efforts. Private investments in deep-sea carbon sequestration projects have surged in recent years, indicating growing interest and support for this approach. Various organizations are exploring the use of plant biomass from sources like seaweed and terrestrial vegetation to facilitate carbon storage in the deep ocean. While each strategy has its advantages and challenges, further research is needed to evaluate their efficacy and environmental impact.
The study by UC Santa Barbara researchers sheds light on the promising role of anoxic marine basins in carbon sequestration, offering a potentially effective and sustainable solution to reduce atmospheric carbon levels. As global efforts to address climate change intensify, innovative approaches like deep-sea biomass storage could play a crucial role in achieving climate goals. Continued research, collaboration, and careful consideration of potential risks are essential to ensure the success of deep-sea carbon sequestration initiatives.