Brian Bergamaschi
Dr. Brian Bergamaschi is a research biogeochemist with the USGS California Water Science Center and adjunct Faculty at California State University Sacramento.
Brian received a Ph.D. in Chemical Oceanography from the University of Washington, in Seattle, WA, where he specialized in analyzing the sources and fates of natural organic material in the environment. His main interests are in understanding processes of carbon and nutrient cycling in aquatic environments and related biogeochemical processes. His particular interest is developing methods to quantify interactions between physical and biogeochemical processes. His research ranges in scale from light-mediated molecular transformations, to tidally driven wetland exchange, to effects of changing continental-scale nutrient fluxes on coastal carbon processes. His current projects largely focus on aquatic biogeochemical processes, aquatic habitat quality and carbon cycling in aquatic systems.
Science and Products
Methylmercury and Low Dissolved Oxygen Events in Suisun Marsh
Mercury and Dissolved Organic Matter in Delta Wetlands
Sources of Disinfection Byproduct-forming Material in the State Water Project
High-Speed Mapping of Nutrient Distributions and Water Quality Survey - Lower South San Francisco Bay
Dynamics of zooplankton in the Cache Slough Complex
Phytoplankton production and nutrient transformations in shallow water wetland habitats
Interactions Between Physical Processes and Suspended Sediment Quality in Relation to Spawning Migrations of Delta Smelt
Causes and Relevance of Phytoplankton Blooms in the Northern Sacramento-San Joaquin Delta
Effects of Aquatic Vegetation on Water Quality and Residence Time in the Bay-Delta
Transport of dissolved organic matter by river networks from mountains to the sea: a re-examination of the role of flow across temporal and spatial scales
Optical signals of water for prediction of wastewater contamination, human-associated bacteria, and fecal indicator bacteria in surface water of Great Lake tributaries from 2011 to 2016
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
High-Resolution Measurements to Identify Effects of Aquatic Vegetation on Water Quality and Stratification
Assessing spatial variability of nutrients and related water quality constituents in the California Sacramento-San Joaquin Delta at the landscape scale: 2018 High resolution mapping surveys (ver. 2.0, October 2023)
High-speed, continuous water quality mapping of Utah Lake, Salt Lake City, UT
Continuous underway water quality and water isotope measurements in a hydrodynamically complex tidal environment
Trihalomethane precursors: Land use hot spots, persistence during transport, and management options
Hydrologic export is a major component of coastal wetland carbon budgets
Tidal wetland gross primary production across the continental United States, 2000–2019
The use of stable isotope-based water age to evaluate a hydrodynamic model
Spatial variability of phytoplankton in a shallow tidal freshwater system reveals complex controls on abundance and community structure
Procedures for using the Horiba Scientific Aqualog® fluorometer to measure absorbance and fluorescence from dissolved organic matter
Direct and indirect effects of tides on ecosystem-scale CO2 exchange in a brackish tidal marsh in Northern California
Potential for negative emissions of greenhouse gases (CO2, CH4 and N2O) through coastal peatland re-establishment: Novel insights from high frequency flux data at meter and kilometer scales
Using paired in situ high frequency nitrate measurements to better understand controls on nitrate concentrations and estimate nitrification rates in a wastewater-impacted river
Irrigation as a fuel pump to freshwater ecosystems
Dissolved organic matter compositional change and biolability during two storm runoff events in a small sgricultural watershed
Synthesis of data from high-frequency nutrient and associated biogeochemical monitoring for the Sacramento–San Joaquin Delta, northern California
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
Filter Total Items: 22
Methylmercury and Low Dissolved Oxygen Events in Suisun Marsh
The primary purpose of the USGS portion of this proposed study is to evaluate if spectrophotometric and spectrofluorometric methods are useful for identifying organic sources of oxygen demand by analyzing water-quality samples (DO, BOD, Chl, SSC, Salinity, THg, MeHg) collected by other agencies and project participants. Sources to be evaluated include algal production, vegetation, soils, and...Mercury and Dissolved Organic Matter in Delta Wetlands
Between 1860 and 1914, hydraulic mining activities sent more than 800,000,000 cubic yards of mercury-laden sediment into the Delta altering the landscape, water flows, and contributing to the leveeing and reclamation of the Delta's marshes. Transport of mercury from historic mining areas continues today. The sedimentary supply of mercury to the Delta and in Delta sediments (cinnabar, metacinnabar...Sources of Disinfection Byproduct-forming Material in the State Water Project
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 the amount and source of the DOC, both of which...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.Dynamics of zooplankton in the Cache Slough Complex
Our purpose is to investigate what controls the distribution and abundance of fish prey within the Cache Slough Complex (CSC).Phytoplankton production and nutrient transformations in shallow water wetland habitats
The objectives of this study are to quantify and characterize (1) phytoplankton production on Liberty Island, (2) utilization and transformation of nutrients, and (3) attenuation/loss of phytoplankton as the material is transported from Liberty Iisland into Cache Slough.Interactions Between Physical Processes and Suspended Sediment Quality in Relation to Spawning Migrations of Delta Smelt
The proposed study is designed to better establish relationships between patterns of delta smelt abundance and properties of suspended particles as measured by optical and acoustical techniques.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.Effects of Aquatic Vegetation on Water Quality and Residence Time in the Bay-Delta
The spread of invasive aquatic vegetation in the Sacramento-San Joaquin Delta is having a profound impact on the Delta’s natural habitat. The presence of these “aquatic weeds” has been shown to alter water velocity and increase water clarity, posing threats to native fish species, specifically the threatened Delta Smelt. These aquatic plants can also affect the foodweb by altering nutrient...Transport of dissolved organic matter by river networks from mountains to the sea: a re-examination of the role of flow across temporal and spatial scales
The transport of dissolved organic matter (DOM) by rivers is an important component of the global carbon cycle, affects ecosystems and water quality, and reflects biogeochemical and hydrological processes in watersheds. Understanding the fundamental relationships between discharge and DOM concentration and composition reveals important information about watershed flow paths, soil flushing, connect - Data
Filter Total Items: 21
Optical signals of water for prediction of wastewater contamination, human-associated bacteria, and fecal indicator bacteria in surface water of Great Lake tributaries from 2011 to 2016
Data are from water samples collected from tributaries of the Great Lakes at three different drainage basin scales, including 1). watershed scale: 8 tributaries of the Great Lakes, 2). subwatershed scale: 5 locations from the greater Milwaukee, Wisconsin area, and 3). small scale: 213 storm sewers and open channel locations in three subwatersheds within the Great Lakes Basin including the Middle BSpatial 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 oHigh-Resolution Measurements to Identify Effects of Aquatic Vegetation on Water Quality and Stratification
The dataset documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta of the Sacramento-San Joaquin River Delta of California, USA. The dataset includes surface mapping, depth profile, and discrete data for nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, and chlAssessing spatial variability of nutrients and related water quality constituents in the California Sacramento-San Joaquin Delta at the landscape scale: 2018 High resolution mapping surveys (ver. 2.0, October 2023)
The dataset documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta, Central Delta, and the Western Delta out to Suisun Bay in the Sacramento-San Joaquin River Delta of California, USA. The dataset includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, and cHigh-speed, continuous water quality mapping of Utah Lake, Salt Lake City, UT
Real-time, high frequency (1-second sample interval), georeferenced water quality data was collected in Utah Lake, Utah. Utah Lake is located approximately 45 miles south of Salt Lake City, Utah, and approximately 5 miles west of Provo, Utah. Data was collected on 8/1/16 over an approximate 6.5-hour period (8:00 14:30 h PST) while underway. Sample water was continuously pumped through a pickup tuContinuous underway water quality and water isotope measurements in a hydrodynamically complex tidal environment
Real-time, high frequency (1-second sample interval) GPS location, water quality, and water isotope (δ2H, δ18O) data was collected in the Cache Slough Complex (CSC), located in the northern San Francisco Bay Delta (SFBD). Data was collected on 10/01/2014 for an approximate 4-hour period (10:30 14:30 h PST) while underway on the R/V Mary Landsteiner, a 26-foot USGS vessel. Sample water was pumped - Publications
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Trihalomethane 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. HernesHydrologic export is a major component of coastal wetland carbon budgets
Coastal wetlands are among the most productive habitats on Earth and sequester globally significant amounts of atmospheric carbon (C). Extreme rates of soil C accumulation are widely assumed to reflect efficient C storage. Yet the fraction of wetland C lost via hydrologic export has not been directly quantified, since comprehensive budgets including direct estimates of lateral C loss are lacking.AuthorsMatthew Bogard, Brian A. Bergamaschi, David Butman, Frank Anderson, Sara Knox, Lisamarie Windham-MyersTidal wetland gross primary production across the continental United States, 2000–2019
We mapped tidal wetland gross primary production (GPP) with unprecedented detail for multiple wetland types across the continental United States (CONUS) at 16‐day intervals for the years 2000–2019. To accomplish this task, we developed the spatially explicit Blue Carbon (BC) model, which combined tidal wetland cover and field‐based eddy covariance tower data into a single Bayesian framework, and uAuthorsR.A. Feagin, I. Forbrich, T. P. Huff, J.G. Barr, J. Ruiz-Plancarte, J.D. Fuentes, R.G. Najjar, R. Vargas, A. Vazquez Lule, L. Windham-Myers, Kevin D. Kroeger, E. J. Ward, G. W. Moore, M. Leclerc, K. W. Krauss, C.L. Stagg, M. Alber, S. H. Knox, K. V. R. Schafer, T.S. Bianchi, J. A. Hutchings, H. Nahrawi, A. Noormets, B. Mitra, A. Jaimes, A.L. Hinson, Brian A. Bergamaschi, J.S. King, G. MiaoThe use of stable isotope-based water age to evaluate a hydrodynamic model
Transport time scales are common metrics of the strength of transport processes. Water age is the time elapsed since water from a specific source has entered a study area. An observational method to estimate water age relies on the progressive concentration of the heavier isotopes of hydrogen and oxygen in water that occurs during evaporation. The isotopic composition is used to derive the fractioAuthorsEdward Gross, Stephen Andrews, Brian A. Bergamaschi, Bryan D. Downing, Rusty Holleman, Scott Burdick, John DurandSpatial 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 B. 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 KendallProcedures for using the Horiba Scientific Aqualog® fluorometer to measure absorbance and fluorescence from dissolved organic matter
Advances in spectroscopic techniques have led to an increase in the use of optical measurements (absorbance and fluorescence) to assess dissolved organic matter composition and infer sources and processing. Although optical measurements are easy to make, they can be affected by many variables rendering them less comparable, including by inconsistencies in sample collection (for example, filter porAuthorsAngela M. Hansen, Jacob Fleck, Tamara E. C. Kraus, Bryan D. Downing, Travis von Dessonneck, Brian A. BergamaschiDirect and indirect effects of tides on ecosystem-scale CO2 exchange in a brackish tidal marsh in Northern California
We investigated the direct and indirect influence of tides on net ecosystem exchange (NEE) of carbon dioxide (CO2) in a temperate brackish tidal marsh. NEE displayed a tidally driven pattern with obvious characteristics at the multiday scale, with greater net CO2uptake during spring tides than neap tides. Based on the relative mutual information between NEE and biophysical variables, this was drivAuthorsSara Knox, Lisamarie Windham-Myers, Frank Anderson, Cove Sturtevant, Brian A. BergamaschiPotential for negative emissions of greenhouse gases (CO2, CH4 and N2O) through coastal peatland re-establishment: Novel insights from high frequency flux data at meter and kilometer scales
High productivity temperate wetlands that accrete peat via belowground biomass (peatlands) may be managed for climate mitigation benefits due to their global distribution and notably negative emissions of atmospheric carbon dioxide (CO2) through rapid storage of carbon (C) in anoxic soils. Net emissions of additional greenhouse gases (GHG)—methane (CH4) and nitrous oxide (N2O)—are more difficult tAuthorsLisamarie Windham-Myers, Brian A. Bergamaschi, Frank A. Anderson, Sarah Knox, Robin Miller, Roger FujiiUsing paired in situ high frequency nitrate measurements to better understand controls on nitrate concentrations and estimate nitrification rates in a wastewater-impacted river
We used paired continuous nitrate ( ) measurements along a tidally affected river receiving wastewater discharge rich in ammonium ( ) to quantify rates of change in concentration ( ) and estimate nitrification rates. sensors were deployed 30 km apart in the Sacramento River, California (USA), with the upstream station located immediately above the regional wastewater treatment plant (WWTP). We uAuthorsTamara E. C. Kraus, Katy O'Donnell, Bryan D. Downing, Jon R. Burau, Brian A. BergamaschiIrrigation as a fuel pump to freshwater ecosystems
We generated a detailed time series of total dissolved hydrolyzable amino acids (DHAA) in a watershed dominated by irrigated agriculture in northern California, USA to investigate the roles of hydrologic and seasonal changes on the composition of dissolved organic matter (DOM). DHAA are sensitive indicators of the degradation state and reactivity of DOM. DHAA concentrations ranged from 0.55 to 9.9AuthorsSandrine Matiasek, Brian A. Pellerin, Robert G.M. Spencer, Brian A. Bergamaschi, Peter J. HernesDissolved organic matter compositional change and biolability during two storm runoff events in a small sgricultural watershed
Agricultural watersheds are globally pervasive, supporting fundamentally different organic matter source, composition, and concentration profiles in comparison to natural systems. Similar to natural systems, agricultural storm runoff exports large amounts of organic carbon from agricultural land into waterways. But intense management of upper soil layers, waterway channelization, wetland and riparAuthorsRobert S Eckard, Brian A. Pellerin, Brian A. Bergamaschi, Philip A. M. Bachand, Sandra M. Bachand, Robert G. M. Spencer, Peter J. HernesSynthesis of data from high-frequency nutrient and associated biogeochemical monitoring for the Sacramento–San Joaquin Delta, northern California
Executive SummaryThis report is the second in a series of three reports that provide information about high-frequency (HF) nutrient and biogeochemical monitoring in the Sacramento–San Joaquin Delta of northern California (Delta). The purpose of this report is to synthesize the data available from a nutrient and water-quality HF (about every 15 minutes) monitoring network operated by the U.S. GeoloAuthorsBryan D. Downing, Brian A. Bergamaschi, Tamara E.C. KrausNon-USGS Publications**
Bergamaschi, B.A. and Hedges, J.I. (1995) A Multichambered Apparatus for HF Solvolysis Experiments - Reaction of Cellulose HF Solvolysis Products with Acetic-Acid and Acetic-Anhydride. Carbohydrate Research 267, 115-126. https://doi.org/10.1016/0008-6215(94)00279-OHedges, J.I., Bergamaschi, B.A. and Benner, R. (1994) Comparative Analyses of DOC and DON in Natural Water - Erratum (Vol 41, Pg 121, 1989). Marine Chemistry 46, 407-408. https://doi.org/10.1016/0304-4203(94)90035-3Hedges, J.I., Bergamaschi, B.A. and Benner, R. (1993) Comparative Analyses of DOC and DON in Natural Water. Marine Chemistry 41, 121-134. https://doi.org/10.1016/0304-4203(93)90110-AHopkinson, C., Cifuentes, L., Burdige, D., Fitzwater, S., Hansell, D., Henrichs, S., Kahler, P., Koike, I., Walsh, T. and Bergamaschi, B. (1993) Measurement of Dissolved Organic Carbon and Nitrogen in Natural Waters - DON Subgroup Report. Marine Chemistry 41, 23-36. https://doi.org/10.1016/0304-4203(93)90103-UHedges, J.I. and Bergamaschi, B.A. (1992) Seawater Carbon Measurement. Nature 359, 202-202. https://doi.org/DOI 10.1038/359202a0**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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