Submarine groundwater discharge as a source of nutrients to the North Pacific and Arctic coastal ocean

• Published in: Marine chemistry 2016-11, Vol.186, p.167-177
• Main Authors: Lecher, Alanna L., Chien, Chia-Te, Paytan, Adina
• Format: Article
• Language: English
• Subjects: Arctic; Arctic Ocean; Coastal; Discharge; Fluxes; Groundwater; Nitrates; Nutrients; Rivers; Shorelines; Trace metals
• ISSN: 0304-4203; 1872-7581
• DOI: 10.1016/j.marchem.2016.09.008

Primary productivity in both the Arctic Ocean and the Gulf of Alaska (GOA) is nitrogen limited in the summer when light limitation is relieved, and stratification in the GOA inhibits nutrient fluxes from deep water sources. Concentrations of nutrients and trace metals in these regions are higher closer to shore, and thus rivers have been attributed as the primary coastal source of nutrients and trace metals. Here we evaluate the role of Submarine Groundwater Discharge (SGD), a previously unquantified source of nutrients and trace metals to the coastal Arctic Ocean and GOA. SGD is an especially enriched in nitrate relative to other nutrients, contributing 1.2±0.4mol NO3 day−1m−1 of shoreline of the Arctic Ocean. In the GOA, both SGD-associated nitrate flux (4.3±2.1 NO3 day−1m−1 of shoreline) and silicate flux (13±6 SiO4 day−1m−1 of shoreline), are substantial when compared to other external nutrient sources. Conservative extrapolations indicate overall SGD supplies more nitrate (1.5–17.5 times) to the GOA than rivers. •Submarine groundwater discharge rivals rivers as an N source to the Gulf of Alaska.•Fe fluxes in the Gulf of Alaska coastal aquifer are not deplete relative to N.•Submarine groundwater discharge is a source of N and Fe to the Arctic Ocean.•Submarine groundwater discharge's importance will increase with less sea ice.•The first study of this source's nutrient fluxes to the Arctic Ocean.