Logo of the PBL Netherlands Environmental Assessment Agency
To the main menuTo the main content

Global land–ocean linkage: direct inputs of nitrogen to coastal waters via submarine groundwater discharge

Article | 26-09-2013
Coast with surf and dunes

The role of submarine groundwater discharge (SGD), the leakage of groundwater from aquifers into coastal waters, in coastal eutrophication has been demonstrated mostly for the North American and European coastlines, but poorly quantified in other regions. Here, we present the first spatially explicit global estimates of N inputs via SGD to coastal waters and show that it has increased from about 1.0 to 1.4 Tg of nitrate per year over the second half of the 20th century.

Since this increase is not accompanied by an equivalent increase of groundwater phosphorus (P) and silicon (Si), SGD transport of nitrate is an important factor for the development of harmful algal blooms in coastal waters. Groundwaterfluxes of N are linked to areas with high runoff and intensive anthropogenic activity on land, with Southeast Asia, parts of North and Central America, and Europe being hot spots.

Author(s)Arthur Beusen, C.P. Slomp (UU), Lex Bouwman
Publication date26-09-2013
PublicationEnvironmental Research Letters (Volume 8, Issue 3)
ReferenceISSN 1748-9326