1,2,- 1CAS Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, Chi
- 2University of Chinese Academy of Sciences, Beijing 100049, China.
- 3State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, Xiamen University.
The efficacy of ocean iron fertilization (OIF) is limited, with the dissolution of diatom biological silica (BSi) representing a significant impediment, which results in the slow sinking and rapid remineralization of organic carbon in surface seawater. A mineral-enhanced biological pump (MeBP) strategy has been proposed, based on the use of clay minerals that agglomerate with BSi and inhibit BSi dissolution. This approach is presumed to facilitate an increase in the amount of BSi deposited and a decrease in organic carbon loss. In order to evaluate the efficacy of the MeBP strategy, montmorillonite was selected as the model clay mineral, and Chaetoceros as the model diatom in this study. A verification test was conducted in a 5-tonne water column with varying concentrations of montmorillonite. The findings demonstrated that diatoms disintegrated montmorillonite, releasing Si and Al, which were subsequently incorporated by the diatoms as framework elements to construct BSi. Al inhibits the dissolution of BSi and facilitates the aggregation of BSi with residual montmorillonite, thereby promoting the deposition of organic carbon and protecting it from degradation. The quantity of BSi present in the deposit increased by more than 18 when montmorillonite was introduced, compared to the amount observed in the absence of montmorillonite. The organic storage rate increased by more than one order of magnitude. Furthermore, montmorillonite has been observed to promote diatom blooms and delay diatom decay by modifying the diatom growth environment. Consequently, MeBP is demonstrated to be an effective approach for significantly improving the efficiency of the vertical carbon export of OIF, which represents a promising strategy for enhancing the oceanic biological pump using clay minerals.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (Grant Nos. 42172047, 42188102), Guang-dong Basic and Applied Basic Research Foundation (Grant Nos. 2022A1515010824, 2024B1515040003), and the ONCE project.
How to cite: Liu, D., Shen, Y., Yu, R., Li, M., and Jiao, N.: Mineral-enhanced biological pump (MeBP): a promising strategy for the effective supplementation of ocean iron fertilization (OIF), One Ocean Science Congress 2025, Nice, France, 3–6 Jun 2025, OOS2025-404, https://doi.org/10.5194/oos2025-404, 2025.
