Sekar Selvam, Perumal Muthukumar
Department of Geology, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India.
Department of Geology, V.O. Chidambaram College, Tuticorin, Tamil Nadu, India.
Mar Environ Res. 2025 Sep;210:107301. doi: 10.1016/j.marenvres.2025.107301. Epub 2025 Jun 14.
The precise quantification and understanding of submarine groundwater discharge (SGD) pose significant challenges, despite its critical role in the dynamics of coastal ecosystems. The present study conducted in the Punnakayal Estuary, Tamil Nadu, India presents an innovative approach to unveil hidden flows of groundwater discharge using a combination of radon (Rn) tracing and Geographic Information Systems (GIS) Topology. Radon (Rn), a radioactive gas that occurs naturally acts as a unique tracer for SGD due to its ability to partition between groundwater and surface water. In the present study, radon concentrations were measured systematically across the estuarine environment to identify areas of SGD influence. The data were then integrated into a GIS framework, where spatial topology was employed to analyze the intricate connectivity between surface water bodies, subsurface groundwater and SGD pathways. The results reveal a comprehensive view of SGD dynamics within the Punnakayal Estuary with the fresh SGD of 4.52 × 10 m/s through GIS modelling approach. Notably, the combination of radon tracing and GIS topology unveils previously concealed pathways of groundwater discharge. High-flow accumulation zones indicative of SGD was identified, shedding light on the spatial distribution of this vital hydrological process. SST of the region was also calculated to validate this approach. This research contributes to our understanding of coastal hydrogeology and ecosystem health in the Punnakayal region, with implications for sustainable coastal management and resource conservation. The integrated approach of radon tracing and GIS topology offers a robust methodology applicable to similar coastal environments globally, addressing the challenges associated with the hidden flows of submarine groundwater discharge. By uncovering the intricate subsurface interactions between groundwater and estuarine systems, was not only advances scientific knowledge but also provides valuable understandings to protect and preserve the delicate balance of coastal ecosystems.
尽管海底地下水排放（SGD）在沿海生态系统动态中起着关键作用，但其精确量化和理解仍面临重大挑战。本研究在印度泰米尔纳德邦的蓬纳卡亚尔河口进行，提出了一种创新方法，即结合氡（Rn）示踪和地理信息系统（GIS）拓扑来揭示地下水排放的隐藏流动。氡（Rn）是一种天然存在的放射性气体，由于其能够在地下水和地表水之间分配，因此是SGD的独特示踪剂。在本研究中，系统地测量了整个河口环境中的氡浓度，以确定受SGD影响的区域。然后将数据整合到GIS框架中，利用空间拓扑分析地表水水体、地下地下水和SGD路径之间的复杂连通性。结果通过GIS建模方法揭示了蓬纳卡亚尔河口内SGD动态的全面情况，新鲜SGD为4.52×10米/秒。值得注意的是，氡示踪和GIS拓扑的结合揭示了以前隐藏的地下水排放路径。确定了指示SGD的高流量聚集区，揭示了这一重要水文过程的空间分布。还计算了该地区的海表面温度以验证此方法。这项研究有助于我们了解蓬纳卡亚尔地区的沿海水文地质和生态系统健康状况，对可持续的沿海管理和资源保护具有重要意义。氡示踪和GIS拓扑的综合方法提供了一种适用于全球类似沿海环境的强大方法，解决了与海底地下水排放隐藏流动相关的挑战。通过揭示地下水与河口系统之间复杂的地下相互作用，不仅推进了科学知识，还为保护和维护沿海生态系统的微妙平衡提供了有价值的认识。
