Spatial and Seasonal Variation in Surface Water pCO2 in the Ganges, Brahmaputra, and Meghna Rivers on the Indian Subcontinent
Spatial and Seasonal Variation in Surface Water pCO2 in the Ganges, Brahmaputra, and Meghna Rivers on the Indian Subcontinent
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DOI：
10.1007/s10498-015-9262-2
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发表时间：
2015-05
影响因子：
1.6
通讯作者：
Takuya Manaka;H. Ushie;D. Araoka;Souya Otani;A. Inamura;A. Suzuki;H. Zakir Hossain;H. Kawahata
中科院分区：
文献类型：
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作者：
Takuya Manaka;H. Ushie;D. Araoka;Souya Otani;A. Inamura;A. Suzuki;H. Zakir Hossain;H. Kawahata
最近的研究表明，在短时间内，从河水中直接释放到大气中的CO2对全球碳循环的重要性。在这项研究中，我们调查了碳酸盐系统，包括pCO2的空间和季节变化，在孟加拉国的三个主要喜马拉雅河流：恒河，雅鲁藏布江，和Meghna河，和他们的潜在重要性。尽管已知pCO 2在这些河流的上游较低，但由于活跃的化学风化作用，我们发现pCO 2值高于下游沿着的大气pCO 2水平，在这些下游，深层土壤已经发育，高气温促进了活跃的土壤呼吸。通过一个简单的混合计算，我们发现，在这些河流水碳酸盐系统的季节变化是由地下水流控制。在雨季，大部分低地被淹没，地下水流对河水碳酸盐系统的贡献增加，导致较高的pCO2值。在未来的研究中，需要进行更详细的空间和季节调查，以澄清陆地生态系统，包括河流和二氧化碳通量在全球碳循环中的作用，并研究在全球变暖的情况下，这种作用将如何变化。
Recent studies have remarked on the importance of direct CO2release from river water into the atmosphere on the global carbon cycle over a short timescale. In this study, we investigated carbonate systems, including spatial and seasonal variations ofpCO2, in three major Himalayan rivers in Bangladesh: the Ganges, Brahmaputra, and Meghna Rivers, and their potential importance. AlthoughpCO2is known to be low in the upper reaches of these rivers, owing to active chemical weathering, we observedpCO2values higher than the atmosphericpCO2level along their lower reaches, where deep soils have developed and where high air temperatures promote active soil respiration. By a simple mixing calculation, we found that seasonal variations in these river water carbonate systems are controlled by subsurface water flows. In the rainy season, most of the lowlands are inundated, and the contribution of subsurface flow to river water carbonate systems increases, resulting in higherpCO2values. In future research, more detailed spatial and seasonal investigations are required to clarify the role of terrestrial ecosystems, including rivers and the CO2flux to the atmosphere, in the global carbon cycle and to examine how that role will change under global warming.