Tamara Kraus is a Research Soil Scientist at the California Water Science Center.
Tamara Kraus received a master's degree in Agronomy and a doctoral degree in Soils and Biogeochemistry from the University of California, Davis. She has been working at the USGS California Water Science Center (CAWSC) in Sacramento since 2004, where she does research on the cycling of carbon and nutrients, and the linkages between terrestrial and aquatic systems. Her projects span a range of topics from identifying sources of dissolved organic carbon and to inform drinking water quality management, to using constructed wetlands to reverse subsidence, to the application of in situ coagulation to remove mercury from surface waters, to understanding the links between nutrients and phytoplankton.
Professional Experience
2010-present Soil Scientist, US Geological Survey, Sacramento, CA
2006-2009 Post Doctoral Researcher, US Geological Survey through UC Davis, Sacramento, CA
2004-2005 National Research Council Post Doctoral Fellow with US Geological Survey, Sacramento, CA
1996-2003 Research Assistant: Soil Chemistry Lab, , University of California, Davis, CA
1996-2003 Teaching Assistant: Soils and Biogeochemistry, , University of California, Davis, CA
1995-1996 Post-Graduate Researcher/Project Manager, University of California, Davis, CA
1992-1994 Research Assistant: Agronomy, University of California, Davis, CA
Education and Certifications
Ph.D., Soils and Biogeochemistry, 2002, University of California, Davis , CA Dissertation: Tannins and Nutrient Dynamics in Forest Soils: Plant-Litter-Soil Interactions
M.S., Agronomy and Range Science, 1994, University of California, Davis, CAThesis: Weed Abundance and Competition in Water-Seeded versus Drill-Seeded Rice in California
B.A., Biology and Society: Agriculture and the Environment, 1989, College of Arts and Sciences Cornell University, Ithaca, NY
Science and Products
High-frequency Monitoring of Delta Island Drainage Waters
Biogeochemistry Group
Assessing Sediment Nutrient Storage and Release in California's Sacramento-San Joaquin Delta
Evaluating the effects of wastewater-derived nutrients on phytoplankton abundance and community structure in the San Francisco Estuary and Delta
Water Quality of San Francisco Bay Research and Monitoring Project
Modeling Nitrogen Reduction Benefit to Invasive Aquatic Vegetation vs. Native Phytoplankton
Monitoring Cyanotoxins in California's Sacramento-San Joaquin Delta: Fixed Stations and High-Resolution Mapping Surveys
Trends in Dissolved Organic Carbon (DOC) in the Sacramento-San Joaquin Delta
Subsidence in the Sacramento-San Joaquin Delta
High-Speed Mapping of Nutrient Distributions and Water Quality Survey - Lower South San Francisco Bay
Nitrogen Dynamics Along the Sacramento River and Links to Phytoplankton Dynamics: Resolving Spatial and Temporal Variability Using In-Situ, High-Frequency Measurements and Other Tools
Causes and Relevance of Phytoplankton Blooms in the Northern Sacramento-San Joaquin Delta
Water quality, nutrient, and phytoplankton data from Franks Tract, Mildred Island, and neighboring channels in the California Sacramento-San Joaquin Delta: 2022 and 2023 High-resolution mapping surveys
Assessing spatial variability of nutrients, phytoplankton and related water-quality constituents in the California Sacramento-San Joaquin Delta at the landscape scale: 2020-2021 High-resolution mapping surveys
Assessing spatial variability of nutrients, phytoplankton, and related water quality constituents in the California Sacramento-San Joaquin Delta during treated wastewater effluent holds: August and September 2019 high resolution mapping surveys
Phytoplankton Species Composition and Abundance in the Sacramento-San Joaquin River Delta: Microscopic Enumeration of USGS Samples, beginning in 2016
Assessing spatial variability of nutrients, phytoplankton, and related water quality constituents in the California Sacramento-San Joaquin Delta related to the 2015 installation of the False River Emergency Drought Barrier: 2015 and 2016 high-resolution m
Absorbance and fluorescence measurements and concentrations of disinfection by-products in source water and finished water in the McKenzie River Basin, Oregon: 2012-2014
Produced water chemistry data for the Lost Hills, Fruitvale, and North and South Belridge study areas, Southern San Joaquin Valley, California (version 1.1, September 2020)
Characterization of water residence time, nutrients, phytoplankton and related water quality constituents in the Cache Slough Complex of the California Sacramento-San Joaquin Delta in 2017 and 2018
Spatial assessment of nutrients and water-quality constituents in Suisun Marsh with the salinity control gate reoperation experiment; a Delta Smelt Resiliency Strategy experiment 2018
Assessment of water-quality in the California Sacramento-San Joaquin Delta during a North Delta directed flow action: August - October 2018
Assessment of nutrients and water-quality constituents in the North Delta during Yolo Bypass flooding events in March 2017
Assessment of nutrients and water-quality constituents at the Sacramento-San Joaquin River Confluence during a phytoplankton bloom in July 2017
A novel boat-based field application of a high-frequency conductometric ammonium analyzer to characterize spatial variation in aquatic ecosystems
Sacramento River nutrient change study
Sources and characteristics of dissolved organic carbon in the McKenzie River, Oregon, related to the formation of disinfection by-products in treated drinking water
Stable isotopes provide insight into sources and cycling of N compounds in the Sacramento-San Joaquin Delta, California, USA
Ocean connectivity drives trophic support for consumers in an intermittently closed coastal lagoon
Changing nitrogen inputs to the northern San Francisco Estuary: Potential ecosystem responses and opportunities for investigation
Lateral carbon exports from drained peatlands: An understudied carbon pathway in the Sacramento-San Joaquin Delta, California
Trihalomethane precursors: Land use hot spots, persistence during transport, and management options
Spatial variability of phytoplankton in a shallow tidal freshwater system reveals complex controls on abundance and community structure
Chemically enhanced treatment wetland to improve water quality and mitigate land subsidence in the Sacramento-San Joaquin Delta: Cost and design considerations
Sequestration and transformation in chemically enhanced treatment wetlands: DOC, DBPPs and Nutrients
Aluminum- and iron-based coagulation for in-situ removal of dissolved organic carbon, disinfection byproducts, mercury and other constituents from agricultural drain water
Bay- Delta Water Quality, Nutrient and Phytoplankton Mapping | US Geological Survey
Data visualization tool created for California's Bay-Delta Regional Monitoring Program. This web applicaton visualizes nutrients and phytoplankton spatially and temporally.
Science and Products
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Filter Total Items: 15
High-frequency Monitoring of Delta Island Drainage Waters
From the second half of the 19th century, land reclamation has transformed the Sacramento-San Joaquin Delta (Delta). The landscape of the Delta has gone from a network of shifting waterways and tidal marshland to channels and islands fixed in position by hardened levees.Biogeochemistry Group
The Biogeochemistry (BGC) Group uses an interdisciplinary approach to address surface water quality issues and food web dynamics throughout California, particularly in the Sacramento-San Joaquin Delta and San Francisco Bay.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 the effects of wastewater-derived nutrients on phytoplankton abundance and community structure in the San Francisco Estuary and Delta
Planned upgrades to the Sacramento Regional wastewater treatment plant (SRWTP) will substantially reduce nutrient discharge and also alter the types and amounts of nutrients being distributed across the San Francisco Delta and Estuary (Delta). One highly anticipated outcome of lower nutrients is improved productivity in the phytoplankton communities that supply aquatic food webs, which should...Water Quality of San Francisco Bay Research and Monitoring Project
Since 1969, the U.S. Geological Survey has maintained a research project in the San Francisco Bay-Delta system to measure and understand how estuarine systems and tidal river deltas function and change in response to hydro-climatic variability and human activities.Modeling Nitrogen Reduction Benefit to Invasive Aquatic Vegetation vs. Native Phytoplankton
Phytoplankton comprise the bottom of the aquatic food web and the abundance of phytoplankton serves as an indicator of healthy aquatic habitats. In the Sacramento-San Joaquin River Delta (Delta), competing with phytoplankton for required nitrogen, invasive aquatic vegetation (IAV) has increased exponentially in recent years. Once established, IAV can negatively impact local ecosystems and...Monitoring Cyanotoxins in California's Sacramento-San Joaquin Delta: Fixed Stations and High-Resolution Mapping Surveys
California’s Sacramento-San Joaquin River Delta (Delta) provides drinking water to about 30 million people and irrigation water to the agriculturally rich Central Valley. The Delta is also home to numerous threatened and endangered native species. The health of the Delta's aquatic ecosystems, and fish in particular, have long been in a state of decline. This is associated with decreasing...Trends in Dissolved Organic Carbon (DOC) in the Sacramento-San Joaquin Delta
Water from the Sacramento-San Joaquin Delta contains high concentrations of disinfection byproduct-forming (DBP-forming) materials when treated for potable use. DBPs form when dissolved organic compounds (DOC) in water react with disinfectants such as chlorine and ozone during the water treatment process. The amount of DBPs that form is a function of both the amount and source of the DOC, both of...Subsidence in the Sacramento-San Joaquin Delta
The Sacramento-San Joaquin Delta is part of the San Francisco Estuary, home to a diverse flora and fauna, including several threatened and endangered species, has a large area of prime farmland, and serves as the hub of California's freshwater-delivery system that moves water from the wet north to the dry southern part of the State.High-Speed Mapping of Nutrient Distributions and Water Quality Survey - Lower South San Francisco Bay
This project aims to characterize spatial heterogeneity for key water quality parameters, and pilot the use of underway-flowthrough mapping of biogeochemical properties as a cost-effective approach to monitoring.Nitrogen Dynamics Along the Sacramento River and Links to Phytoplankton Dynamics: Resolving Spatial and Temporal Variability Using In-Situ, High-Frequency Measurements and Other Tools
The overall project objective is to further our understanding of the link between nitrogen and phytoplankton dynamics in the Sacramento River and to elucidate effects of wastewater treatment plant effluent on food web dynamics.Causes and Relevance of Phytoplankton Blooms in the Northern Sacramento-San Joaquin Delta
Phytoplankton are an important part of aquatic food webs and ecosystems. These single-celled plants grow faster in the stronger light of spring or summer, resulting in population explosions called phytoplankton blooms. These blooms in turn feed zooplankton (free-floating aquatic microorganisms), providing food for many aquatic species, including fish, shrimp, crabs, and other invertebrates. - Data
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Water quality, nutrient, and phytoplankton data from Franks Tract, Mildred Island, and neighboring channels in the California Sacramento-San Joaquin Delta: 2022 and 2023 High-resolution mapping surveys
Surface water quality, water isotope, and phytoplankton enumeration data were collected to evaluate the impact of an Emergency Drought Barrier (EDB) in False River in the Sacramento-San Joaquin Delta. Data were collected on six days during 2022 and 2023 (June 7, June 21, July 27, August 9, October 12, November 30, 2022, and February 21, 2023). Sampling occurred in Franks Tract, Mildred Island, theAssessing spatial variability of nutrients, phytoplankton and related water-quality constituents in the California Sacramento-San Joaquin Delta at the landscape scale: 2020-2021 High-resolution mapping surveys
The dataset documents the spatial and temporal variability of nutrients, phytoplankton, and related water quality parameters at high spatial resolution in the Sacramento-San Joaquin River Delta and Suisun Bay of California, USA. The dataset includes nitrate, ammonium, orthophosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, and chlorophyll as well as information aboutAssessing spatial variability of nutrients, phytoplankton, and related water quality constituents in the California Sacramento-San Joaquin Delta during treated wastewater effluent holds: August and September 2019 high resolution mapping surveys
The study is comprised of daily survey data consisting of high resolution mapping and discrete sample collection of nutrients, phytoplankton, and related water quality constituents conducted in the Sacramento River, Georgiana Slough, and the North and South Forks of the Mokelumne River on August 28 and September 10-12, 2019, coincident with planned holds of treated wastewater effluent from SacramePhytoplankton Species Composition and Abundance in the Sacramento-San Joaquin River Delta: Microscopic Enumeration of USGS Samples, beginning in 2016
This dataset contains taxonomy, density (cells/mL), and biovolume (μm3/mL) data for phytoplankton sampled across the Sacramento San Joaquin River Delta and San Francisco Bay (Bay-Delta) beginning in 2016. Whole water phytoplankton samples were collected intermittently during special projects and during routine visits to service continuous monitoring stations. Samples were preserved with Lugol’s ioAssessing spatial variability of nutrients, phytoplankton, and related water quality constituents in the California Sacramento-San Joaquin Delta related to the 2015 installation of the False River Emergency Drought Barrier: 2015 and 2016 high-resolution m
This data release documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the western and central portion of the Sacramento-San Joaquin River Delta of California, USA. The data set includes water residence time, nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, and cAbsorbance and fluorescence measurements and concentrations of disinfection by-products in source water and finished water in the McKenzie River Basin, Oregon: 2012-2014
This data release contains the results from a study that characterized the concentration and quality of dissolved organic carbon (DOC) in the McKenzie River, a relatively pristine watershed in western Oregon, and its link to forming disinfection by-products (DBPs) in treated drinking water. The study aimed to identify the primary source(s) of DOC in source water for the Eugene Water and Electric BProduced water chemistry data for the Lost Hills, Fruitvale, and North and South Belridge study areas, Southern San Joaquin Valley, California (version 1.1, September 2020)
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (Water Board) collected produced water and casing gas samples from petroleum wells and other oil-field sites in selected oil fields in the southern San Joaquin Valley in Kern County in 2016 and 2017. The samples were collected as part of the Water Boards Regional Groundwater Monitoring ProgramCharacterization of water residence time, nutrients, phytoplankton and related water quality constituents in the Cache Slough Complex of the California Sacramento-San Joaquin Delta in 2017 and 2018
Data was collected in the Cache Slough Complex located in the northern San Francisco Estuary to characterize water quality parameters at high spatial resolution. Data collection was conducted on three separate occasions: October 2017, May 2018, and October 2018. Data set includes nitrate, ammonium, ortho-phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, cSpatial assessment of nutrients and water-quality constituents in Suisun Marsh with the salinity control gate reoperation experiment; a Delta Smelt Resiliency Strategy experiment 2018
This data release documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in Suisun Marsh and Suisun Bay in the San Francisco Estuary of California, USA. The data set includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, chlorophyll, blue-green algal pigments, andAssessment of water-quality in the California Sacramento-San Joaquin Delta during a North Delta directed flow action: August - October 2018
This report documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta in the Sacramento-San Joaquin River Delta of California, USA. The data set includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, and chlorophyll . Data-collection cruises were coAssessment of nutrients and water-quality constituents in the North Delta during Yolo Bypass flooding events in March 2017
The data release contains data for the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta in the Sacramento-San Joaquin River Delta of California, USA. The data set includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, and chlorophyll. Data-collection cruAssessment of nutrients and water-quality constituents at the Sacramento-San Joaquin River Confluence during a phytoplankton bloom in July 2017
This report documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta in the Sacramento-San Joaquin River Delta of California, USA. The data set includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, and chlorophyll. Data-collection were conducted o - Publications
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A novel boat-based field application of a high-frequency conductometric ammonium analyzer to characterize spatial variation in aquatic ecosystems
Documenting dissolved inorganic nitrogen (DIN) concentration and form at appropriate temporal and spatial scales is key to understanding aquatic ecosystem health, particularly as DIN fuels primary productivity. In addition to point and non-point source nutrient inputs, factors such as hydrology, geomorphology, temperature, light, and biogeochemical transformations influence nutrient dynamics in suAuthorsEmily Teresa Richardson, Angela Hansen, Tamara E. C. Kraus, Bryan D. Downing, Don Forsberg, John Stillian, Katy O'Donnell, Crystal Lee Sturgeon, Brian A. BergamaschiSacramento River nutrient change study
The Sacramento River Nutrient Change Study (SRiNCS) was developed with input from multiple stakeholders in the Delta Regional Monitoring Program, as well as the State Water Contractors. We tracked the effects of changes in nutrient loading resulting from a short-term wastewater hold at the Sacramento River Wastewater Treatment Plant (SRWTP). In the summer of 2019, scheduled wastewater effluent holAuthorsLisa Thompson, Timothy D. Mussen, Michael Cook, Justin Nordin, James Noss, Ursula Bigler, Srividhya Ramamoorthy, Gry Mine Berg, Sara Driscoll, Clifton Herrmann, Wim J. Kimmerer, Toni Ignoffo, Tamara E. C. Kraus, Joseph K. Fackrell, Brian Bergamaschi, Marianne Guerin, Richard RachieleSources and characteristics of dissolved organic carbon in the McKenzie River, Oregon, related to the formation of disinfection by-products in treated drinking water
Executive SummaryThis study characterized the concentration and quality of dissolved organic carbon (DOC) in the McKenzie River, a relatively undeveloped watershed in western Oregon, and its link to forming disinfection by-products (DBPs) in treated drinking water. The study aimed to identify the primary source(s) of DOC in source water for the Eugene Water & Electric Board’s (EWEB) conventional tAuthorsKurt D. Carpenter, Tamara E. C. Kraus, Angela M. Hansen, Bryan D. Downing, Jami H. Goldman, Jonathan Haynes, David Donahue, Karl MorgensternStable isotopes provide insight into sources and cycling of N compounds in the Sacramento-San Joaquin Delta, California, USA
River deltas and their diverse array of aquatic environments are increasingly impacted by anthropogenic inputs of nitrogen (N). These inputs can alter the N biogeochemistry of these systems and promote undesirable phenomena including harmful algae blooms and invasive aquatic macrophytes. To examine N sources and biogeochemical processes in the Sacramento-San Joaquin Delta, a river delta located inAuthorsJoseph K. Fackrell, Tamara E. C. Kraus, Megan B. Young, Carol Kendall, Sara PeekOcean connectivity drives trophic support for consumers in an intermittently closed coastal lagoon
Estuarine food webs are complex, as marine, freshwater, and terrestrial inputs combine and contribute variable amounts of organic material. Seasonal fluctuations in precipitation amplify the dynamism inherent to estuarine food webs, particularly in lagoonal estuaries, which can be seasonally closed and disconnected from the ocean in low-runoff periods (bar-built lagoons). Despite their abundance aAuthorsMatthew Young, Frederick Feyrer, Darren Fong, Rachel C. Johnson, Tamara E. C. Kraus, Veronica Larwood, Elizabeth Stumpner, Megan B. YoungChanging nitrogen inputs to the northern San Francisco Estuary: Potential ecosystem responses and opportunities for investigation
Anthropogenic activities have resulted in elevated ambient nitrogen (N) and phosphorus (P) concentrations in many regions of the Sacramento-San Joaquin Delta and Suisun Bay (northern San Francisco Estuary, (nSFE). The Sacramento Regional wastewater treatment plant (SRWTP WWTP) currently acts as the largest N point source to the system, discharging 13,000-15,000 kg/d of ammonium-N (NH4) near the nSAuthorsDavid Senn, Tamara E. C. Kraus, Amy Richey, Brian A. Bergamaschi, Larry R. Brown, Louise Conrad, Christopher A. Francis, Wim Kimmerer, Raphael Kudela, Timothy G. Otten, Alexander E. Parker, April Robinson, Anke Mueller-Solger, Dylan Stern, Janet ThompsonLateral carbon exports from drained peatlands: An understudied carbon pathway in the Sacramento-San Joaquin Delta, California
Degradation of peatlands via drainage is increasing globally and destabilizing peat carbon (C) stores. The effects of drainage on the timing and magnitude of lateral C losses from degraded peatlands remains understudied. We measured spatial and temporal variability in lateral C exports from three drained peat islands in the Sacramento‐San Joaquin Delta in California across the 2017 and 2018 waterAuthorsChristina M. Richardson, Joseph K. Fackrell, Tamara E. C. Kraus, Megan B. Young, Adina PaytanTrihalomethane precursors: Land use hot spots, persistence during transport, and management options
To meet drinking water regulations, rather than investing in costly treatment plant operations, managers can look for ways to improve source water quality; this requires understanding watershed sources and fates of constituents of concern. Trihalomethanes (THMs) are one of the major classes of regulated disinfection byproducts, formed when a specific fraction of the organic carbon pool—referred toAuthorsRobert S. Eckard, Brian A. Bergamaschi, Brian A. Pellerin, Tamara E. C. Kraus, Peter J. HernesSpatial variability of phytoplankton in a shallow tidal freshwater system reveals complex controls on abundance and community structure
Estuaries worldwide are undergoing changes to patterns of aquatic productivity because of human activities that alter flow, impact sediment delivery and thus the light field, and contribute nutrients and contaminants like pesticides and metals. These changes can influence phytoplankton communities, which in turn can alter estuarine food webs. We used multiple approaches-including high-resolution wAuthorsElizabeth Stumpner, Brian A. Bergamaschi, Tamara E. C. Kraus, Alexander Parker, Francis Wilkerson, Bryan D. Downing, Richard Dugdale, Michael T. Murrell, Kurt D. Carpenter, James Orlando, Carol KendallChemically enhanced treatment wetland to improve water quality and mitigate land subsidence in the Sacramento-San Joaquin Delta: Cost and design considerations
Water quality impairment and land surface subsidence threaten the viability of the Sacramento-San Joaquin Delta (Delta), a critical component of California’s water conveyance system. Current day irrigation drainage through Delta island peat soils impacts drinking water treatment and is linked to mercury transport, potentially posing both ecological and public health concerns. Hybrid coagulation-trAuthorsPhilip A. M. Bachand, Tamara E. C. Kraus, William R. Horwath, Nathan R. Hatch, Sandra M. BachandSequestration and transformation in chemically enhanced treatment wetlands: DOC, DBPPs and Nutrients
We examined the effectiveness of chemically enhanced treatment wetlands (CETWs), wetlands that received water treated with coagulants, to remove dissolved organic carbon (DOC), disinfection byproduct precursors (DBPPs), nutrients and metals from agricultural drain water. Wetlands consisted of controls with no coagulant addition, ferric sulfate dosed and polyaluminum chloride dosed treatments. CETWAuthorsPhilip A. M. Bachand, Sandra M. Bachand, Tamara E. C. Kraus, Dylan Stern, Yan Ling Liang, William R. HorwathAluminum- and iron-based coagulation for in-situ removal of dissolved organic carbon, disinfection byproducts, mercury and other constituents from agricultural drain water
Agricultural production on wetland soils can be significant sources of dissolved organic carbon (DOC), disinfection byproduct precursors, mercury and nutrients to downstream water bodies and accelerate land subsidence. Presented as a potential solution for in-situ water quality improvement and land subsidence mitigation, chemically enhanced treatment wetlands (CETWs) were used to leverage both coaAuthorsSandra M. Bachand, Tamara E. C. Kraus, Dylan Stern, Yan Ling Liang, William R. Horwath, Philip A. M. Bachand - Web Tools
Bay- Delta Water Quality, Nutrient and Phytoplankton Mapping | US Geological Survey
Data visualization tool created for California's Bay-Delta Regional Monitoring Program. This web applicaton visualizes nutrients and phytoplankton spatially and temporally.
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