1. Introduction

A significant part of the flux of dissolved substances from land to the sea occurs through river transport via the drainage basins network (Turner et al. 1999). The input from major rivers is gauged and well analyzed with relatively precise estimates of the quantities of freshwater and chemical constituents entering the marine environment. Recently, submarine groundwater discharge (SGD) has been recognized as an important factor influencing coastal zones (Burnett et al. 2006; McCoy and Corbett 2009; Moore 2010). It has been indicated that subterranean non-point pathways of material transport may be of considerable importance in some coastal areas (Beck et al. 2010; Lee et al. 2011; Kim and Kim 2014). SGD is an essential component of the water cycle and can be, in selected areas, comparable in volume to the riverine flux (e.g. Atlantic Ocean, Moore 2010).