Multidimensional impacts of ocean alkalinity enhancement on aquatic ecosystems and fisheries carbon sequestration capacity

According to the “2024 Global Carbon Budget” report, emission reduction alone is insufficient to avert the dual crises of ocean acidification and climate change. As a result, negative ocean emissions—particularly alkalinity enhancement—have gained scientific attention as promising carbon sequestration strategies. This paper examines research on negative marine emissions by analyzing the structure and functioning of aquatic ecosystems. A comprehensive analysis of studies sourced from the China National Knowledge Infrastructure (CNKI) and Web of Science (WOS) databases was conducted to assess the impact of alkalinity enhancement sinks on marine systems. Various species and environmental factors were considered in the investigation. Furthermore, preliminary estimates of the carbon sink capacity of shellfish-algae systems were provided for nine coastal provinces of China and across six continents, concerning oceanic pH levels. By summarizing the current state of research on negative global ocean emissions, this review aims to evaluate the potential risks and synergistic benefits associated with the alkalinity enhancement sinks to advance the science in this area and lay the groundwork for future research.