I study the biological and geochemical influences of sediments, more specifically the environmental and biogeochemical controls driving nutrient (i.e. nitrogen, iron, and sulfur) cycling in aquatic wetland environments, such as estuaries. As major ecological habitats, these unique environments have been plagued by a myriad of water and sediment quality issues, many of which are further altered by climate change. The role of sediment and its impacts on ecosystem health, water quality, and aquatic life is particularly important, yet this field has received little research attention. My research employs biogeochemical methods to investigate questions regarding the impact of sediments on water quality and the modification of nutrient cycling under climactic conditions. It seeks to elucidate the fate, transport, and transformative processes that factor into nutrient cycling and loadings and illuminate the role that these nutrients play in mobilizing or immobilizing toxic metals, such as arsenic, selenium, uranium, and chromium.
My research has focused on three sites in the western United States: the bar-built Pescadero Estuary (Pescadero, CA), Baylands Nature Preserve (Palo Alto, CA), and Fraser Experimental Forest (Fraser, CO). These sites represent a range of wetland environments with large observed concentrations of sulfides and toxic heavy metals in the sediment.
Richards, C. M. and Pallud, C. (2016). Kinetics of sulfate reduction and sulfide precipitation rates in sediments of a bar-built estuary (Pescadero, California). Water Research.94: 86-102.
Richards, C. M. and Pallud C. (2015). “Spatio-temporal physical and geochemical characterization of a California bar-built estuary,” Goldschmidt Conference, Prague, Czech Republic, Talk.
Richards, C. M. and Pallud C. (2014). “Safeguarding from Sulfide: Can Pescadero Estuary be restored?,” Restore America’s Estuaries 7th National Summit on Coastal and Estuarine Restoration and 24th Biennial Meeting of the Coastal Society (RAE-TCS Summit), Washington, DC, Sea Grant Association Best Student Poster.
Richards, C. M. and Pallud C. (2014). “Sulfur redox processes in littoral sediments of the intermittent Pescadero Estuary,” American Chemical Society 248th National Meeting & Exposition, San Francisco, CA, Talk.
Honors and Awards
2015 - James P. Bennett Agricultural Fund Award
2015 - California Sea Grant Graduate Traineeship
2014 - Sea Grant Association Best Student Poster, Restore America's Estuaries Summit