JPEG Images of Cores Collected in August 2006 in the Nauset Marsh Area of Cape Cod, Massachusetts

In order to test hypotheses about groundwater flow under and into estuaries and the Atlantic Ocean, geophysical surveys, geophysical probing, submarine groundwater sampling, and sediment coring were conducted by U.S. Geological Survey (USGS) scientists at Cape Cod National Seashore (CCNS) from 2004 through 2006. Coastal resource managers at CCNS and elsewhere are concerned about nutrients that are entering coastal waters via submarine groundwater discharge, which are contributing to eutrophication and harmful algal blooms. The research carried out as part of the study described here was designed, in part, to help refine assumptions required by earlier versions of models about the nature of submarine groundwater flow and discharge at CCNS. This study was conducted in four phases, with a variety of field techniques and equipment employed in each phase. Phase 1 consisted of continuous resistivity profiling (CRP) surveys of the entire study area conducted in 2004. Phase 2 consisted of CRP ground-truthing via resistivity probe measurements and submarine groundwater sampling from hydraulically-drive piezometers using a barge in the Salt Pond/Nauset Marsh area in 2005. Phase 3 consisted of supplemental detailed CRP surveys in the Salt Pond/Nauset Marsh area in 2006. Finally, Phase 4 consisted of sediment coring and porewater extraction in the Salt Pond/Nauset Marsh area later in 2006 to supplement the 2005 sampling.

为验证发育于河口及大西洋下方、并注入该两类水体的地下水流动相关假说，美国地质调查局（U.S. Geological Survey, USGS）科研人员于2004至2006年间，在科德角国家海岸（Cape Cod National Seashore, CCNS）开展了地球物理勘探、地球物理探测、海底地下水采样与沉积物岩芯采集工作。科德角国家海岸及其他沿海区域的海岸资源管理者对通过海底地下水排泄进入近岸水体的营养盐深表担忧——此类营养盐会加剧水体富营养化与有害藻华的发生。本项研究的相关工作在设计之初，便部分旨在辅助完善早期模型中关于科德角国家海岸区域地下水流动与海底排泄特性的预设假设。本研究共分为四个阶段，各阶段均采用了多样化的野外技术与设备：第一阶段为2004年对整个研究区域开展的连续电阻率剖面（Continuous Resistivity Profiling, CRP）测量；第二阶段为2005年在盐池/诺塞特沼泽区域，依托驳船使用液压驱动测压管开展电阻率探针探测以完成连续电阻率剖面的地面校验，并同步采集海底地下水样本；第三阶段为2006年在盐池/诺塞特沼泽区域开展的补充性精细连续电阻率剖面测量；第四阶段则为2006年后期在同一区域开展的沉积物岩芯采集与孔隙水提取工作，以补充2005年的采样内容。