John G Warden, Ph.D.
Science and Products
Assessing Sediment Nutrient Storage and Release in California's Sacramento-San Joaquin Delta
Sediments represent an important pool of nutrients in the Sacramento-San Joaquin Delta (Delta). The exchange of nutrients between the water column and the benthos impacts water quality and effects phytoplankton, harmful algal blooms, aquatic vegetation, and drinking water quality. To date, there is very limited information about nutrient pools in Delta sediments, nor how these nutrients are...
Evaluating a laboratory flume microbiome as a window into natural riverbed biogeochemistry
Riverbeds are hotspots for microbially-mediated reactions that exhibit pronounced variability in space and time. It is challenging to resolve biogeochemical mechanisms in natural riverbeds, as uncontrolled settings complicate data collection and interpretation. To overcome these challenges, laboratory flumes are often used as proxies for natural...
Kaufman, Matthew H.; Warden, John; Cardenas, M. Bayani; Stegen, James C.; Graham, Emily B.; Brown, Joseph The importance of groundwater flow to the formation of modern thrombolitic microbialites
Modern microbialites are often located within groundwater discharge zones, yet the role of groundwater in microbialite accretion has yet to be resolved. To understand relationships between groundwater, microbialites, and associated microbial communities, we quantified and characterized groundwater flow and chemistry in active thrombolitic...
Warden, John; Coshell, Lee; Rosen, Michael R.; Breecker, Daniel O.; Ruthrof, Katinka X.; Omelon, Christopher R.
Scientists Assess Sediment Nutrient Storage and Release in California's Sacramento-San Joaquin Delta
California Water Science Center scientists have begun the first comprehensive assessment of sediment nutrient inventories and fluxes in the Sacramento-San Joaquin Delta (Delta). Their findings will serve as a baseline for assessing water quality improvements following upcoming upgrades to the Sacramento Regional Wastewater Treatment Plant and wetland restoration efforts.