北江河水溶解无机碳同位素的季节变化

贾国东; 陈法锦; 邓文锋

doi:10.3799/dqkx.2012.043

北江河水溶解无机碳同位素的季节变化

doi: 10.3799/dqkx.2012.043

贾国东^1,,
陈法锦^{1, 2},
邓文锋¹

1.
中国科学院广州地球化学研究所, 广东广州 510640
2.
国家海洋局第二海洋研究所, 浙江杭州 310012

基金项目:

中国科学院知识创新工程项目 kzcx2-yw-138-2

详细信息

作者简介:
贾国东(1969-), 博士, 研究员, 主要从事生物地球化学和同位素地球化学研究.E-mail: jiagd@gig.ac.cn

中图分类号: P641.3
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- 被引次数: 0
出版历程
- 收稿日期: 2010-08-20
- 刊出日期: 2012-03-15

Seasonal Variations of Dissolved Inorganic Carbon Isotope in the Beijiang River

1.
Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
2.
Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China

摘要

摘要: 在有碳酸盐岩分布的河流流域, 河水地球化学主要反映的是风化速率较高的碳酸盐矿物风化的信息, 而硅酸盐矿物风化的信息往往被掩盖掉.北江流域碳酸盐岩和硅酸岩分布广泛, 为追踪其中的硅酸盐矿物风化的信息, 分析了北江河水中溶解无机碳同位素的时空变化.河水样品按4个季节自北江的上游到下游采集6个样点, 分析结果显示, 除上游武江的采样点同位素值季节变化不大外, 中下游采样点的同位素值有明显季节变化, 主要表现在6月份的δ¹³C_DIC显著变轻(-16‰~-19‰).在详细剖析矿物风化过程对碳同位素的影响后, 指出除了显著的碳酸盐矿物风化过程外, 北江流域在夏季还存在明显的硅酸盐矿物风化过程, 大大提高了流域的碳汇作用.
- 溶解无机碳 /
- 同位素 /
- 风化 /
- 河水 /
- 地球化学 /
- 环境工程
Abstract: In watershed with occurrence of carbonate minerals, information of carbonate weathering can be easily traced by river chemistry due to its higher weathering rate, whereas signals of silicate weathering tend to be concealed. In this study, temporal and spatial variations of carbon isotope of dissolved inorganic carbon are employed to trace silicate weathering in the Beijiang River, whose watershed is covered by both carbonate and silicate. Water samples were collected from six sites from upstream to downstream for all seasons. Our results show that there is an obvious seasonality in isotope values at sites in the midstream and downstream, displaying marked lighter values in June (-16‰ to -19‰) except for the upstream sites showing less varying carbon isotope values. Taking into consideration of constrains of various processes on dissolved inorganic carbon isotope, we propose that silicate weathering is greatly enhanced in summer in addition to carbonate weathering, which strengthens carbon sink significantly.
- dissolved inorganic carbon /
- isotope /
- weathering /
- river water /
- geochemistry /
- environmental engineering

HTML全文

图 1 北江流域示意

灰色区域为碳酸盐岩或含碳酸盐地层，其中的圆点区代表被覆盖的碳酸盐岩地区.转绘自1∶250万广东省水文地质图.五星符号和对应的数字表示采样点的位置

Fig. 1. Schematic of the Beijiang watershed

下载: 全尺寸图片幻灯片

图 2 北江河水δ¹³C_DIC的时空变化(采样点对应于图 1中的数字)

Fig. 2. Temporal and spatial variations of δ¹³C_DIC in Beijiang River

下载: 全尺寸图片幻灯片

图 3 北江河水δ¹³C_DIC与DIC产生过程导致的同位素理论值的比较

Fig. 3. Comparisons of the Beijiang River δ¹³C_DIC with theoretical values of DIC-producing processes

下载: 全尺寸图片幻灯片

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