According to Schlüter et al. (2004) chloride pore water profiles can be used to investigate submarine groundwater discharge. Chloride can be used as a conservative tracer, as it is enriched in seawater and depleted in groundwater. Three different shapes of chloride pore water profiles reflect three different transport modes within marine sediments. A chloride profile showing constant concentrations with depth indicates that no submarine groundwater is present. A chloride profile with a linear decline indicates a diffusive mixing between groundwater and seawater and a concave shaped chloride profile represents an advective admixture of submarine groundwater from below. Stable isotope ratios in the water molecule may also be used to trace and quantify the sources of a submarine groundwater discharge.