期刊
ESTUARINE COASTAL AND SHELF SCIENCE
卷 179, 期 -, 页码 66-78出版社
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ecss.2015.12.004
关键词
Oxygen depletion; In situ measurements; Exposed tidal beach; Intertidal environment; Sediment-water exchanges; Aquitaine; Truc Vert beach
We conducted six field campaigns to investigate the spatial and temporal evolution of pore water oxygen content on a high-energy sandy beach aquifer during several tidal cycles at different seasons. We buried autonomous probes in intertidal sands to record dissolved oxygen saturation, salinity, temperature and water head at a 2-10 min frequency. Oxygen concentrations display significant changes both with time (tide and seasons) and space (cross-shore and vertical variations). Seawater circulation in tidal sands forms a saline pore water circulation cell with oxygen-saturated pore water in the zone of seawater recharge. Oxygen-depleted pore water in the lower beach is the result of in situ respiration processes that occur during seawater circulation. Oxygen depletion varies throughout the year and anoxic conditions are reached at the end of spring, as planktonic organic matter becomes abundant in seawater and more organic matter is therefore supplied to pore water. On a shorter time scale (weeks to minutes), oxygen variations are driven directly by physical forcing. Tidal amplitude affects the extent of the saltwater circulation cell and the associated location of the recharging and discharging zones of the beach. The evolution of the water table level during the tidal cycle influences the circulatiori of pore water in the sand and ultimately, the timing of oxygen variations during flood and ebb. This first in situ study in a high-energy sandy beach shows that the dynamics of pore water oxygen are governed by biogeochemical processes at the seasonal scale and by physical forcing at the time scale of minutes to a few days. (C) 2015 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据