Institute of the Surface-Earth System Science Research, Tianjin University, Tianjin 300072, China.
College of Urban and Environmental Sciences, Peking University, Peking 100871, China.
Sci Total Environ. 2018 Feb 15;615:1-8. doi: 10.1016/j.scitotenv.2017.09.253. Epub 2017 Sep 29.
During silicate weathering, atmospheric carbon dioxide (CO) is consumed and base cations are released from silicate minerals to form carbonate and bicarbonate ions, which are finally deposited as carbonate complexes. Continental silicate weathering constitutes a stable carbon sink that is an important influence on long-term climate change, as it sequesters atmospheric carbon dioxide at a million-year time scale. Traditionally, CO sequestered through silicate weathering is estimated by measuring the flux of the base cations to watersheds. However, plants also absorb considerable amounts of base cations. Plant biomass is often removed from ecosystems during harvesting. The base cations are subsequently released after decomposition of the harvested plant materials, and thereby enhance CO consumption related to weathering. Here, we analyze plant biomass storage-harvest fluxes (production and removal of biomass from forests) of base cations in forests across China to quantify the relative contribution of forest trees to the terrestrial weathering-related carbon sink. Our data suggest that the potential CO consumption rate for biomass-related silicate weathering (from the combined action of with afforestation/reforestation, controlled harvesting and rock powder amendment) in Chinese forests is 7.9±4.1Tg COyr. This represents ~34% of the chemical weathering rate in China. Globally, forests may increase CO sequestration through biologically-mediated silicate weathering by ~32%.
在硅酸盐风化过程中，大气中的二氧化碳（CO）被消耗，而碱金属阳离子则从硅酸盐矿物中释放出来，形成碳酸盐和碳酸氢盐离子，最终作为碳酸盐络合物沉积。大陆硅酸盐风化构成了一个稳定的碳汇，对长期气候变化有重要影响，因为它在百万年的时间尺度上隔离了大气中的二氧化碳。传统上，通过硅酸盐风化固定的 CO 是通过测量基阳离子向流域的通量来估算的。然而，植物也会吸收大量的碱金属阳离子。在收获过程中，植物生物量经常从生态系统中去除。此后，在分解收获的植物材料后，基阳离子被释放出来，从而增强了与风化相关的 CO 消耗。在这里，我们分析了中国森林中基阳离子的植物生物量储存-收获通量（森林中生物量的生产和去除），以量化森林树木对陆地风化相关碳汇的相对贡献。我们的数据表明，中国森林中与生物量相关的硅酸盐风化（通过造林/再造林、受控收获和岩石粉改良的综合作用）的潜在 CO 消耗速率为 7.9±4.1Tg COyr。这占中国化学风化速率的~34%。在全球范围内，森林可能通过生物介导的硅酸盐风化增加 CO 固存约 32%。
