Global Research Trends and Hotspots on Submarine Groundwater Discharge (SGD): A Bibliometric Analysis.

Qian Ma,Yan Zhang

doi:10.3390/ijerph17030830

Abstract

Submarine groundwater discharge (SGD), a major component of the hydrological cycle, has significant impacts on the sustainable development of the marine environment. This study aimed to examine the literature characteristics and research hotspots of SGD based on Web of Science’s citation database from 1998–2019. With systematic bibliometric analysis, insights were made into multiple aspects including research output, subject categories, journals, countries/territories, institutions, authors, and hotspots and research trends. Results showed that the current amount of publications on SGD has increased exponentially. The characteristics of multi-subject, active international and inter-institutional collaborations were identified. There were 11 core journals publishing the research on SGD, and the number of covered journals increased linearly from 1998. USA had distinct advantages in publication outputs and took the core position in international collaborations. At present, the research hotspots of SGD mainly include the following: dynamics process and estimation of SGD with hydrogeological methods, tracer techniques, geochemical process in subterranean estuary, and dissolved material inputs to coastal waters via SGD. Citation analysis implied much development space in carbon flux transported by SGD and the implement of head as groundwater tracer. These results provided an instructive perspective of the present situation and future research direction on SGD.

Highlights

Submarine groundwater discharge (SGD) refers to any and all flow of water on continental margins from the seabed to the coastal ocean, i.e., the groundwater exchange between land and the sea in short [1]
Since the study of SGD quantification published in Nature [6], processes associated with SGD have attracted more and more attention, and have gradually become a research hotspot in coastal areas
This study presented a systematic bibliometric analysis of literatures on submarine groundwater discharge (SGD) based on Web of Science database during 1998–2019

Summary

Introduction

Submarine groundwater discharge (SGD) refers to any and all flow of water on continental margins from the seabed to the coastal ocean, i.e., the groundwater exchange between land and the sea in short [1]. SGD has been recognized as an important pathway for nutrient, contaminants, and other chemical materials transport to coastal water, which has significant impacts on the sustainable development of marine environment and geochemical cycles [2,3,4]. As an important but hidden input pathway, SGD was neglected for many years for the great difficulty in quantification. Since the study of SGD quantification published in Nature [6], processes associated with SGD have attracted more and more attention, and have gradually become a research hotspot in coastal areas. It was widely reported that SGD provides a large amount of important dissolved mass input to marine environment, including carbon, nutrient and microelements that marine plants and animals need [7,8]. The order of magnitude of SGD was estimated to be 10 to 103 ·m3 d−1 m−1 , which is considerable with the long

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