The influence of diurnal temperatures on the hydrochemistry of a tufa‐depositing stream
The influence of diurnal temperatures on the hydrochemistry of a tufa‐depositing stream
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DOI：
10.1002/hyp.1301
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发表时间：
2003-12
影响因子：
3.2
通讯作者：
R. Drysdale;S. Lucas;K. Carthew
中科院分区：
文献类型：
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作者：
R. Drysdale;S. Lucas;K. Carthew
在澳大利亚新南威尔士州中部的一条石灰华沉积河流Davys Creek，在四个观测期内测量了碳酸盐水化学的日变化。主要离子浓度和连续记录的测量比电导率，pH值和温度表明，CaCO 3沉积量的变化上游的研究达到直接相关的昼夜水温的变化，控制CO2排放到大气中的速率。最大的上游损失发生在中午水温峰值期间，而最小的上游损失发生在日出时，此时水温最低。一年中任何时候的多云天气都会产生小的昼夜水温范围（c。2-5°C），因此，上游CaCO 3损失的变化相对较小（23-50 mg L−1）。晴朗的晴天，特别是在夏季，产生大的昼夜水温变化（高达C。11°C），这反过来又引发了高达100 mg L−1的上游CaCO 3损失的昼夜变化。这意味着，凝灰岩沉积的活跃河段必须在晚上向下游推进，长度增加，白天反之亦然。考虑到戴维斯溪沃茨的温度是日照的函数，基流条件下石灰华沉积范围的变化是主要天气的直接函数。这对石灰华沉积物化石的古气候解释有影响。版权所有© 2003年约翰威利父子有限公司。
At‐a‐station diurnal variations in carbonate hydrochemistry were measured during four observation periods at Davys Creek, a tufa‐depositing stream in central NSW, Australia. Major ion concentrations and continuously logged measurements of specific conductivity, pH and temperature showed that changes in the amount of CaCO3 deposited upstream of the study reach were directly related to changes in diurnal water temperatures, which control the rate of CO2 efflux to the atmosphere. The greatest upstream losses occurred during the mid‐afternoon water temperature peak, whereas the lowest upstream losses occurred at sunrise, when water temperatures were at their lowest. Cloudy days at all times of the year produced small diurnal water temperatures ranges (c. 2–5°C) and, consequently, relatively small changes in upstream CaCO3 loss (23–50 mg L−1) through the day. Clear sunny days, especially during summer months, produced large diurnal water temperature changes (up to c. 11°C), which in turn triggered diurnal changes in upstream CaCO3 loss of up to 100 mg L−1. By implication, the active reach of tufa deposition must advance downstream and increase in length during the evening and vice versa during the day. Given that the temperature of Davys Creek waters are a function of insolation, changes in the reach of tufa deposition under baseflow conditions are a direct function of the prevailing weather. This has implications for the palaeoclimatic interpretation of fossil tufa deposits. Copyright © 2003 John Wiley & Sons, Ltd.