期刊
WATER RESOURCES RESEARCH
卷 56, 期 11, 页码 -出版社
AMER GEOPHYSICAL UNION
DOI: 10.1029/2019WR026866
关键词
groundwater; coastal aquifers; radium; submarine groundwater discharge; ocean chemistry; nutrients
资金
- National Science Foundation [1316250, 1736557]
- Directorate For Geosciences
- Division Of Earth Sciences [1316250] Funding Source: National Science Foundation
- Directorate For Geosciences
- Division Of Ocean Sciences [1736557] Funding Source: National Science Foundation
Marine tracer studies indicate that large volumes of saline groundwater discharge to the ocean in passive margin settings. These results have not found widespread recognition because the location and cause(s) of this submarine groundwater discharge (SGD) are unclear. Here we report observations from a new long-term seafloor monitoring network in the South Atlantic Bight that support large-scale SGD far from shore. In the study area near Charleston, South Carolina, we determined hydrostratigraphy via vibracoring and chirp seismic surveys, collected water samples from seafloor wells, and used heat as a tracer to monitor SGD. We detected significant pulses of saline SGD issuing from the seafloor 10-15 km from shore. These pulses coincided with abrupt sea level declines of up to 30 cm. Based on an analysis of marine conditions at the time, we propose that upwelling-favorable winds depressed sea level in the region, causing saline groundwater to discharge from confined coastal aquifers that connect land and ocean. The combination of stacked confined aquifers and variations in sea level are nearly ubiquitous in passive coastal margins. This previously overlooked combination can explain a wide range of other published observations and promotes more dynamic flows than simple tidal fluctuations. This new mechanism may explain Ra tracer signals in the coastal Atlantic Ocean and supports significant nutrient inputs to the ocean. These large natural geochemical fluxes may be sensitive to groundwater usage on land.
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