Bryan Downing (Former Employee)
Science and Products
Spatially Explicit Mapping of Hydrologic Residence Time Paired with Water Quality Measurements to Determine the Effects of the Emergency Drought Barrier
The purpose of this study is to assess the distribution of water residence times across the central Delta using rapid water isotope measurements (δ2H, δ18O) made with a boat-based flow-through instrument.
Assessment of Baseline Conditions in Liberty Cut
Monitoring habitat quality in the San Francisco Estuary (SFE) and Sacramento-San Joaquin Delta has been limited to mostly monthly discrete measurements of biologically relevant parameters (e.g. phytoplankton, dissolved organic matter (DOM), nutrients) that cannot fully characterize the physical and biogeochemical variability.
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...
Filter Total Items: 14
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
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...
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
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...
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
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...
Laboratory and Field Data for a Performance Evaluation of the PhytoFind, an In-Place Phytoplankton Classification Tool
This data release presents the laboratory and field results of a performance evaluation conducted on the Turner Designs, Inc., PhytoFind, an in-place phytoplankton classification tool. The laboratory evaluation included tests that were designed to characterize PhytoFind performance under a range of conditions that may affect phytoplankton fluorescence and sensor response. Laboratory...
Absorbance 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...
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
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...
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
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...
Assessment 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...
Assessment 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...
Assessment 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...
High-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...
High-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...
Filter Total Items: 38
Assessing spatial variability of nutrients, phytoplankton, and related water-quality constituents in the California Sacramento–San Joaquin Delta at the landscape scale—2018 high resolution mapping surveys
Executive Summary This study examined the abundance and distribution of nutrients and phytoplankton in the tidal aquatic environments of the Sacramento–San Joaquin Delta (Delta) and Suisun Bay, comprising three spatial surveys conducted in May, July, and October of 2018 that used continuous underway high frequency sampling and measurements onboard a high-speed boat to characterize...
Authors
Brian A. Bergamaschi, Tamara E. C. Kraus, Bryan D. Downing, Elizabeth B. Stumpner, Katy O'Donnell, Jeffrey A. Hansen, Jeniffer Soto Perez, Emily T. Richardson, Angela M. Hansen, Alan Gelber
Physics to fish—Understanding the factors that create and sustain native fish habitat in the San Francisco Estuary
Executive SummaryThe Bureau of Reclamation (Reclamation) operates the Central Valley Project (CVP), one of the nation’s largest water projects. Reclamation has an ongoing need to improve the scientific basis for adaptive management of the CVP and, by extension, joint operations with California’s State Water Project. The U.S. Geological Survey (USGS) works cooperatively with the Bureau of...
Authors
Larry R. Brown, David E. Ayers, Brian A. Bergamaschi, Jon R. Burau, Evan T. Dailey, Bryan D. Downing, Maureen A. Downing-Kunz, Frederick V. Feyrer, Brock M. Huntsman, Tamara E. C. Kraus, Tara Morgan, Jessica R. Lacy, Francis Parchaso, Catherine A. Ruhl, Elizabeth B. Stumpner, Paul Stumpner, Janet Thompson, Matthew J. Young
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...
Authors
Emily T. Richardson, Angela Hansen, Tamara E. C. Kraus, Bryan D. Downing, Don Forsberg, John Stillian, Katy O'Donnell, Crystal Lee Sturgeon, Brian A. Bergamaschi
Field techniques for fluorescence measurements targeting dissolved organic matter, hydrocarbons, and wastewater in environmental waters: Principles and guidelines for instrument selection, operation and maintenance, quality assurance, and data reporting
The use of field deployable fluorescence sensors by the U.S. Geological Survey has become increasingly common for a wide variety of surface water and groundwater investigations. This report addresses field deployable fluorometers that measure the fluorescence response of various substances in water exposed to incident light generated by the sensor. An introduction to the basic principles...
Authors
Amanda Booth, Jacob Fleck, Brian A. Pellerin, Angela Hansen, Alexandra Etheridge, Guy M. Foster, Jennifer L. Graham, Brian A. Bergamaschi, Kurt D. Carpenter, Bryan D. Downing, Stewart A. Rounds, JohnFranco Saraceno
Field techniques for the determination of algal pigment fluorescence in environmental waters—Principles and guidelines for instrument and sensor selection, operation, quality assurance, and data reporting
The use of algal fluorometers by the U.S. Geological Survey (USGS) has become increasingly common. The basic principles of algal fluorescence, instrument calibration, interferences, data quantification, data interpretation, and quality control are given in Hambrook Berkman and Canova (2007). Much of the guidance given for instrument maintenance, data storage, and quality assurance in...
Authors
Guy M. Foster, Jennifer L. Graham, Brian A. Bergamaschi, Kurt D. Carpenter, Bryan D. Downing, Brian A. Pellerin, Stewart A. Rounds, John Franco Saraceno
Technical note—Performance evaluation of the PhytoFind, an in-place phytoplankton classification tool
In 2019, the U.S. Geological Survey evaluated the performance of the Turner Designs, Inc. PhytoFind, an in-place phytoplankton classification tool. The sensor was tested with sample blanks, monoculture and mixed phytoplankton cultures, and turbidity challenges in a laboratory, and was tested on a 120-mile survey of the Caloosahatchee and St. Lucie Rivers in Florida, including Lake...
Authors
Brett D. Johnston, Jennifer L. Graham, Guy M. Foster, Bryan D. Downing
Sources 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)...
Authors
Kurt D. Carpenter, Tamara E. C. Kraus, Angela M. Hansen, Bryan D. Downing, Jami H. Goldman, Jonathan Haynes, David Donahue, Karl Morgenstern
The 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...
Authors
Edward Gross, Stephen Andrews, Brian A. Bergamaschi, Bryan D. Downing, Rusty Holleman, Scott Burdick, John Durand
Spatial 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...
Authors
Elizabeth 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 Kendall
Procedures 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...
Authors
Angela M. Hansen, Jacob Fleck, Tamara E. C. Kraus, Bryan D. Downing, Travis von Dessonneck, Brian A. Bergamaschi
Using 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...
Authors
Tamara E. C. Kraus, Katy O'Donnell, Bryan D. Downing, Jon R. Burau, Brian A. Bergamaschi
An introduction to high-frequency nutrient and biogeochemical monitoring for the Sacramento–San Joaquin Delta, northern California
Executive SummaryThis report is the first 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). This first report provides an introduction to the reasons for and fundamental concepts behind collecting HF measurements, and describes the benefits associated...
Authors
Tamara E.C. Kraus, Brian A. Bergamaschi, Bryan D. Downing
Science and Products
Spatially Explicit Mapping of Hydrologic Residence Time Paired with Water Quality Measurements to Determine the Effects of the Emergency Drought Barrier
The purpose of this study is to assess the distribution of water residence times across the central Delta using rapid water isotope measurements (δ2H, δ18O) made with a boat-based flow-through instrument.
Assessment of Baseline Conditions in Liberty Cut
Monitoring habitat quality in the San Francisco Estuary (SFE) and Sacramento-San Joaquin Delta has been limited to mostly monthly discrete measurements of biologically relevant parameters (e.g. phytoplankton, dissolved organic matter (DOM), nutrients) that cannot fully characterize the physical and biogeochemical variability.
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...
Filter Total Items: 14
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
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...
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
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...
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
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...
Laboratory and Field Data for a Performance Evaluation of the PhytoFind, an In-Place Phytoplankton Classification Tool
This data release presents the laboratory and field results of a performance evaluation conducted on the Turner Designs, Inc., PhytoFind, an in-place phytoplankton classification tool. The laboratory evaluation included tests that were designed to characterize PhytoFind performance under a range of conditions that may affect phytoplankton fluorescence and sensor response. Laboratory...
Absorbance 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...
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
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...
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
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...
Assessment 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...
Assessment 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...
Assessment 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...
High-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...
High-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...
Filter Total Items: 38
Assessing spatial variability of nutrients, phytoplankton, and related water-quality constituents in the California Sacramento–San Joaquin Delta at the landscape scale—2018 high resolution mapping surveys
Executive Summary This study examined the abundance and distribution of nutrients and phytoplankton in the tidal aquatic environments of the Sacramento–San Joaquin Delta (Delta) and Suisun Bay, comprising three spatial surveys conducted in May, July, and October of 2018 that used continuous underway high frequency sampling and measurements onboard a high-speed boat to characterize...
Authors
Brian A. Bergamaschi, Tamara E. C. Kraus, Bryan D. Downing, Elizabeth B. Stumpner, Katy O'Donnell, Jeffrey A. Hansen, Jeniffer Soto Perez, Emily T. Richardson, Angela M. Hansen, Alan Gelber
Physics to fish—Understanding the factors that create and sustain native fish habitat in the San Francisco Estuary
Executive SummaryThe Bureau of Reclamation (Reclamation) operates the Central Valley Project (CVP), one of the nation’s largest water projects. Reclamation has an ongoing need to improve the scientific basis for adaptive management of the CVP and, by extension, joint operations with California’s State Water Project. The U.S. Geological Survey (USGS) works cooperatively with the Bureau of...
Authors
Larry R. Brown, David E. Ayers, Brian A. Bergamaschi, Jon R. Burau, Evan T. Dailey, Bryan D. Downing, Maureen A. Downing-Kunz, Frederick V. Feyrer, Brock M. Huntsman, Tamara E. C. Kraus, Tara Morgan, Jessica R. Lacy, Francis Parchaso, Catherine A. Ruhl, Elizabeth B. Stumpner, Paul Stumpner, Janet Thompson, Matthew J. Young
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...
Authors
Emily T. Richardson, Angela Hansen, Tamara E. C. Kraus, Bryan D. Downing, Don Forsberg, John Stillian, Katy O'Donnell, Crystal Lee Sturgeon, Brian A. Bergamaschi
Field techniques for fluorescence measurements targeting dissolved organic matter, hydrocarbons, and wastewater in environmental waters: Principles and guidelines for instrument selection, operation and maintenance, quality assurance, and data reporting
The use of field deployable fluorescence sensors by the U.S. Geological Survey has become increasingly common for a wide variety of surface water and groundwater investigations. This report addresses field deployable fluorometers that measure the fluorescence response of various substances in water exposed to incident light generated by the sensor. An introduction to the basic principles...
Authors
Amanda Booth, Jacob Fleck, Brian A. Pellerin, Angela Hansen, Alexandra Etheridge, Guy M. Foster, Jennifer L. Graham, Brian A. Bergamaschi, Kurt D. Carpenter, Bryan D. Downing, Stewart A. Rounds, JohnFranco Saraceno
Field techniques for the determination of algal pigment fluorescence in environmental waters—Principles and guidelines for instrument and sensor selection, operation, quality assurance, and data reporting
The use of algal fluorometers by the U.S. Geological Survey (USGS) has become increasingly common. The basic principles of algal fluorescence, instrument calibration, interferences, data quantification, data interpretation, and quality control are given in Hambrook Berkman and Canova (2007). Much of the guidance given for instrument maintenance, data storage, and quality assurance in...
Authors
Guy M. Foster, Jennifer L. Graham, Brian A. Bergamaschi, Kurt D. Carpenter, Bryan D. Downing, Brian A. Pellerin, Stewart A. Rounds, John Franco Saraceno
Technical note—Performance evaluation of the PhytoFind, an in-place phytoplankton classification tool
In 2019, the U.S. Geological Survey evaluated the performance of the Turner Designs, Inc. PhytoFind, an in-place phytoplankton classification tool. The sensor was tested with sample blanks, monoculture and mixed phytoplankton cultures, and turbidity challenges in a laboratory, and was tested on a 120-mile survey of the Caloosahatchee and St. Lucie Rivers in Florida, including Lake...
Authors
Brett D. Johnston, Jennifer L. Graham, Guy M. Foster, Bryan D. Downing
Sources 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)...
Authors
Kurt D. Carpenter, Tamara E. C. Kraus, Angela M. Hansen, Bryan D. Downing, Jami H. Goldman, Jonathan Haynes, David Donahue, Karl Morgenstern
The 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...
Authors
Edward Gross, Stephen Andrews, Brian A. Bergamaschi, Bryan D. Downing, Rusty Holleman, Scott Burdick, John Durand
Spatial 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...
Authors
Elizabeth 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 Kendall
Procedures 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...
Authors
Angela M. Hansen, Jacob Fleck, Tamara E. C. Kraus, Bryan D. Downing, Travis von Dessonneck, Brian A. Bergamaschi
Using 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...
Authors
Tamara E. C. Kraus, Katy O'Donnell, Bryan D. Downing, Jon R. Burau, Brian A. Bergamaschi
An introduction to high-frequency nutrient and biogeochemical monitoring for the Sacramento–San Joaquin Delta, northern California
Executive SummaryThis report is the first 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). This first report provides an introduction to the reasons for and fundamental concepts behind collecting HF measurements, and describes the benefits associated...
Authors
Tamara E.C. Kraus, Brian A. Bergamaschi, Bryan D. Downing