岩石风化碳汇研究的最新进展和展望

New progress and prospects in the study of rock-weathering-related carbon sinks

自气候变化的岩石风化控制学说提出至今,学界普遍认为,是硅酸盐的化学风化碳汇作用在控制着长时间尺度的气候变化,而在短时间尺度上硅酸盐风化碳汇与碳酸盐风化碳汇也是旗鼓相当的.然而,最新的研究发现,碳酸盐溶解的快速动力学和硅酸盐岩流域中微量碳酸盐矿物的风化在控制该流域溶解无机碳(DIC)浓度和碳汇上的重要性,使得碳酸盐风化碳汇占整个岩石风化碳汇的94%,而硅酸盐风化仅占6%左右.另一方面,水生光合生物对DIC的利用及其形成的有机质(内源有机碳)的埋藏,使得碳酸盐风化碳汇在任何时间尺度气候变化的控制上可能都是重要的.此外,岩石风化碳汇研究的另一重要进展是发现了碳汇随全球变暖和土地利用变化显著增加,即形成了气候变化的负反馈机制.未来应通过岩石风化碳捕获和储存过程及其控制机理的进一步研究,揭示岩石风化碳汇过程及其气候和土地利用调控潜力,以服务于各国应对气候变化的国家政策制定.重点研究:①岩石风化碳汇过程及其物理、化学和生物控制机理;②硅酸盐岩流域中微量碳酸盐矿物的风化在控制流域DIC浓度及其碳汇上的重要性;③陆地水生光合生物利用DIC产生内源有机碳的效率;④气候变化和土地利用调控岩石风化碳汇的潜力.

It is widely accepted that the chemical weathering of silicate potentially controls long-term climate change by providing a feedback interaction with atmospheric CO2 drawdown by means of the precipitation of carbonate, while on a short time scale, the silicateweathering-related carbon sink is well matched to the carbonate-weathering-related carbon sink. However, new findings show that owing to the rapid kinetics of carbonate dissolution and the importance of small amounts of carbonate minerals in controlling the dissolved inorganic C （DIC） of silicate watersheds, the contribution of silicate weathering to the atmospheric CO2 sink may be only 6%, while the other 94% is accounted for by carbonate weathering. On the other hand, owing to the aquatic photosynthetic uptake of the weathering-related DIC and burial of some of the resulting （autochthonous） organic C, the atmospheric CO2 sink relating to carbonate weathering might be important in controlling both short-term and long-term climate change. Another new finding is that rock-weathering-related carbon sinks have increased with global warming and land-use change, acting as a negative mechanism for global warming. Future investigation should focus on the in-depth study of rock weathering processes and mechanisms in carbon capture and storage, so as to reveal the regulating potential of the carbon sink according to the climate and land use, which will serve countries in their decision making with respect to climate change. Important study topics include （1） rock weathering processes and controlling mechanisms of climate and land use in carbon sinks, （2） the importance of small amounts of carbonate minerals in controlling the DIC and carbon sink of silicate watersheds, （3） the ratio of autochthonous carbon in total organic carbon, and （4） the regulating potential of rock-weathering-related carbon sinks according to climate and land use.