Submarine Groundwater Discharge in the San Juan Archipelago and the Effects of Nitrate Enrichment on Zostera marina L.

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Date
2011-09Author
Bonsell, Christina
Swarzenski, Peter
Wyllie-Echevierria, Sandy
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Submarine groundwater discharge (SGD) can provide vital nutrients to coastal systems.
Conversely, it can also lead to eutrophication of coastal waters, especially if the
groundwater contains anthropogenic pollutants. This paper presents two studies
encompassing this topic: a field study quantifying SGD at four sites in the San Juan
Archipelago in the Northeast Pacific and a mesocosm experiment examining the effects
of nitrate enrichment (30μM and 150μM added) on local Zostera marina L. SGD rates
varied from essentially 0 to 16.7±22.4 cm/day. Results from the mesocosm experiment
indicate that Z. marina under nitrate enrichment performs differently than those under
control conditions. Under 30μM enrichment, photosynthetic capacity increased, while it
decreased under 150μM.