Direct evidence of the feedback between climate and weathering
Direct evidence of the feedback between climate and weathering
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DOI：
10.1016/j.epsl.2008.10.018
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发表时间：
2009-01-15
影响因子：
5.3
通讯作者：
Oskarsson, Niels
中科院分区：
文献类型：
--
作者：
Gislason, Sigurdur R.;Oelkers, Eric H.;Oskarsson, Niels
长期气候温和化通常归因于化学风化;温度和降水越高，风化速度越快。风化作用通过河流输送将二价阳离子释放到海洋中，在那里它们通过沉淀和随后的碳酸盐矿物埋藏促进大气中的CO2下降。为了验证这一广泛持有的假设，我们进行了一项实地研究，确定风化率的8个几乎原始的东北部冰岛河流流域不同的冰川覆盖超过44年。在研究期间，这些集水区的年平均气温和年降水量分别为3.2至4.5摄氏度和80%至530%。统计上显着的线性正相关关系被发现之间的年平均温度和化学风化在所有8个集水区和年平均温度之间的机械风化和径流量在7个集水区。对于每一度的温度升高，径流，机械风化通量，和化学风化通量在这些集水区被发现增加从6%至16%，8%至30%，和4%至14%，分别取决于集水区。与此相反，年降水量是相关的测量通量;年降水量和径流，机械风化，化学风化之间的统计学显着的相关性被发现为3个最少的冰川流域。在44年的时间里，所有集水区的机械和化学风化都随着时间的推移而增加。这些相关性在统计上显着的8个集水区，由于分散在相应的年径流量和年平均温度与时间图。综上所述，这些结果1）表明气候和地球表面风化之间存在显着的反馈，2）表明由于全球变暖，风化率目前正在随着时间的推移而增加。(c)2008 Elsevier B. V.保留所有权利。
Long-term climate moderation is commonly attributed to chemical weathering; the higher the temperature and precipitation the faster the weathering rate. Weathering releases divalent cations to the ocean via riverine transport where they promote the drawdown of CO2 from the atmosphere by the precipitation and subsequent burial of carbonate minerals. To test this widely-held hypothesis, we performed a field study determining the weathering rates of 8 nearly pristine north-eastern Iceland river catchments with varying glacial cover over 44 years. The mean annual temperature and annual precipitation of these catchments varied by 3.2 to 4.5 degrees C and 80 to 530%, respectively during the study period. Statistically significant linear positive correlations were found between mean annual temperature and chemical weathering in all 8 catchments and between mean annual temperature and both mechanical weathering and runoff in 7 of the 8 catchments. For each degree of temperature increase, the runoff, mechanical weathering flux, and chemical weathering fluxes in these catchments are found to increase from 6 to 16%, 8 to 30%, and 4 to 14% respectively, depending on the catchment. In contrast, annual precipitation is less related to the measured fluxes; statistically significant correlations between annual precipitation and runoff, mechanical weathering, and chemical weathering were found for 3 of the least glaciated catchments. Mechanical and chemical weathering increased with time in all catchments over the 44 year period. These correlations were statistically significant for only 2 of the 8 catchments due to scatter in corresponding annual runoff and average annual temperature versus time plots. Taken together, these results 1) demonstrate a significant feedback between climate and Earth surface weathering, and 2) suggest that weathering rates are currently increasing with time due to global warming. (c) 2008 Elsevier B.V. All rights reserved.