Mugu Lagoon is a coastal estuary, located entirely within the Pt. Mugu Naval Air and Weapons Station in Ventura County, about 45 miles north of UCLA. In 1996, Mugu was listed by the State Water Quality Control Board as impaired for mercury, a potent neurotoxin, which is accumulated and biomagnified in the aquatic food web. In 2005, we completed a study on mercury methylation at 10 sampling sites at Mugu, within four habitats at most sites, in the winter and summer. Our results indicated mercury methylation is comparable across the estuary, and there were no seasonal differences; however, significantly higher yields of methylmercury were observed in marsh habitats, compared to other habitats. This winter we will deploy a sensor network at one sampling site within the marsh, to further investigate the biogeochemical controls on mercury cycling. Using an embedded sensor networked array, we will determine under which hydrologic and biogeochemical regimes methylmercury yields are highest. These dense temporal data may be used to determine schemes for "smart sampling," that is, when the conditions are most conducive for mercury methylation.