Natural analogue of the rise and dissolution of liquid CO2 in the ocean
Natural analogue of the rise and dissolution of liquid CO2 in the ocean
复制标题
海洋中液态二氧化碳的上升和溶解的自然模拟
DOI：
10.1016/s1750-5836(07)00092-8
复制
发表时间：
2008
影响因子：
3.9
通讯作者：
T. Ohsumi
中科院分区：
文献类型：
--
作者：
K. Shitashima;Y. Maeda;Yuichi Koike;T. Ohsumi
对冲绳海槽海底热液系统中天然CO2液滴（直径8- 10 mm）的行为进行了观测。天然CO2液滴含有95-98%的CO2、2-3%的H2S和其它气体物种。利用遥控潜水器跟踪CO2微滴上升过程，并利用电导率-温度-深度传感器（CTD）和原位pH/pCO 2传感器测量了微滴上升过程中微滴附近海水的深度、温度、盐度、pH和CO2分压（pCO 2）。上升的CO2液滴的视觉图像是用卫星上的高清电视摄像机记录下来的。400 m × 400 m 4个水平层的填图调查显示，CO2自然排放点上低pH区的分布占优势。CO2液滴的大小和上升速率在上升过程中的水柱深度为1424至679米（跟踪间隔为745米）。CO2液滴在上升过程中逐渐溶解，形成小片状的CO2水合物，这些上升的片状CO2水合物在679 m深度消失。虽然在海底液态CO2排放点上方检测到pH值低至5，但在上升的CO2液滴周围的水柱中没有观察到pH值下降。pH绘图调查的结果表明，只有局部pH值的抑郁症的CO2排放网站。
The behavior of natural carbon dioxide (CO2) droplets (8–10mm in diameter) were observed in a seafloor hydrothermal system at the Okinawa Trough. The natural CO2droplet contain 95–98% of CO2, 2–3% of H2S, and other gas species. The ascending CO2droplets were tracked by a remotely operated vehicle (ROV), and depth, temperature, salinity, pH and partial pressure of CO2(pCO2) in seawater near the CO2droplets were measured during droplet ascent by a conductivity-temperature-depth sensor (CTD) and in situ pH/pCO2sensor. The visual images of the rising CO2droplets were recorded with a high definition television camera on the ROV. A mapping survey (400m×400m; 4 horizontal layers) revealed a dominant distribution of low pH area over the natural CO2venting site. The size and rise rate of CO2droplets decreased during their ascent in the water column from depths of 1424 to 679m (a tracking interval of 745m). The CO2droplets dissolved gradually to become small flakes of CO2hydrate while rising, and these ascending flakes were found to disappear at 679m depth. Although a pH as low as 5 was detected just above the liquid CO2venting site on the seafloor, no detectable pH depression in the water column ambient to the rising CO2droplets was observed. The results of the pH mapping survey showed only localized pH depression over the CO2venting site.