Bryan Downing (Former Employee)
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 38
Optical techniques for the determination of nitrate in environmental waters: Guidelines for instrument selection, operation, deployment, maintenance, quality assurance, and data reporting
The recent commercial availability of in situ optical sensors, together with new techniques for data collection and analysis, provides the opportunity to monitor a wide range of water-quality constituents on time scales in which environmental conditions actually change. Of particular interest is the application of ultraviolet (UV) photometers for in situ determination of nitrate concentrations in
Authors
Brian A. Pellerin, Brian A. Bergamaschi, Bryan D. Downing, John Franco Saraceno, Jessica D. Garrett, Lisa D. Olsen
Sources and characteristics of organic matter in the Clackamas River, Oregon, related to the formation of disinfection by-products in treated drinking water
This study characterized the amount and quality of organic matter in the Clackamas River, Oregon, to gain an understanding of sources that contribute to the formation of chlorinated and brominated disinfection by-products (DBPs), focusing on regulated DBPs in treated drinking water from two direct-filtration treatment plants that together serve approximately 100,000 customers. The central hypothes
Authors
Kurt D. Carpenter, Tamara E.C. Kraus, Jami H. Goldman, John Franco Saraceno, Bryan D. Downing, Brian A. Bergamaschi, Gordon McGhee, Tracy Triplett
Mercury dynamics in a San Francisco estuary tidal wetland: assessing dynamics using in situ measurements
We used high-resolution in situ measurements of turbidity and fluorescent dissolved organic matter (FDOM) to quantitatively estimate the tidally driven exchange of mercury (Hg) between the waters of the San Francisco estuary and Browns Island, a tidal wetland. Turbidity and FDOM—representative of particle-associated and filter-passing Hg, respectively—together predicted 94 % of the observed variab
Authors
Brian A. Bergamaschi, Jacob A. Fleck, Bryan D. Downing, Emmanuel Boss, Brian A. Pellerin, Neil K. Ganju, David H. Schoellhamer, Amy A. Byington, Wesley A. Heim, Mark Stephenson, Roger Fujii
Seeing the light: the effects of particles, dissolved materials, and temperature on in situ measurements of DOM fluorescence in rivers and streams
Field-deployable sensors designed to continuously measure the fluorescence of colored dissolved organic matter (FDOM) in situ are of growing interest. However, the ability to make FDOM measurements that are comparable across sites and over time requires a clear understanding of how instrument characteristics and environmental conditions affect the measurements. In particular, the effects of water
Authors
Bryan D. Downing, Brian A. Pellerin, Brian A. Bergamaschi, John Franco Saraceno, Tamara E.C. Kraus
Methyl mercury dynamics in a tidal wetland quantified using in situ optical measurements
We assessed monomethylmercury (MeHg) dynamics in a tidal wetland over three seasons using a novel method that employs a combination of in situ optical measurements as concentration proxies. MeHg concentrations measured over a single spring tide were extended to a concentration time series using in situ optical measurements. Tidal fluxes were calculated using modeled concentrations and bi-direction
Authors
B.A. Bergamaschi, J.A. Fleck, B.D. Downing, E. Boss, B. Pellerin, N. K. Ganju, D. H. Schoellhamer, A.A. Byington, W.A. Heim, M. Stephenson, R. Fujii
The aquatic real-time monitoring network; in-situ optical sensors for monitoring the nation's water quality
Floods, hurricanes, and longer-term changes in climate and land use can have profound effects on water quality due to shifts in hydrologic flow paths, water residence time, precipitation patterns, connectivity between rivers and uplands, and many other factors. In order to understand and respond to changes in hydrology and water quality, resource managers and policy makers have a need for accurate
Authors
Brian A. Pellerin, Brian A. Bergamaschi, Peter S. Murdoch, Bryan D. Downing, John Franco Saraceno, George R. Aiken, Robert G. Striegl
How reservoirs alter drinking water quality: Organic matter sources, sinks, and transformations
Within reservoirs, production, transformation, and loss of dissolved organic matter (DOM) occur simultaneously. While the balance between production and loss determines whether a reservoir is a net sink or source of DOM, changes in chemical composition are also important because they affect DOM reactivity with respect to disinfection by-product (DBP) formation. The composition of the DOM pool also
Authors
Tamara E.C. Kraus, Brian A. Bergamaschi, Peter J. Hernes, Daniel H. Doctor, Carol Kendall, Bryan D. Downing, Richard F. Losee
Determining sources of dissolved organic carbon and disinfection byproduct precursors to the McKenzie River, Oregon
This study was conducted to determine the main sources of dissolved organic carbon (DOC) and disinfection byproduct (DBP) precursors to the McKenzie River, Oregon (USA). Water samples collected from the mainstem, tributaries, and reservoir outflows were analyzed for DOC concentration and DBP formation potentials (trihalomethanes [THMFPs] and haloacetic acids [HAAFPs]). In addition, optical propert
Authors
Tamara E.C. Kraus, Chauncey W. Anderson, Karl Morgenstern, Bryan D. Downing, Brian A. Pellerin, Brian A. Bergamaschi
Assessing the sources and magnitude of diurnal nitrate variability in the San Joaquin River (California) with an in situ optical nitrate sensor and dual nitrate isotopes
1. We investigated diurnal nitrate (NO3−) concentration variability in the San Joaquin River using an in situ optical NO3− sensor and discrete sampling during a 5‐day summer period characterized by high algal productivity. Dual NO3− isotopes (δ15NNO3 and δ18ONO3) and dissolved oxygen isotopes (δ18ODO) were measured over 2 days to assess NO3− sources and biogeochemical controls over diurnal time‐sc
Authors
Brian A. Pellerin, Bryan D. Downing, Carol Kendall, Randy A. Dahlgren, Tamara E.C. Kraus, John Franco Saraceno, Robert G. M. Spencer, Brian A. Bergamaschi
Quantifying fluxes and characterizing compositional changes of dissolved organic matter in aquatic systems in situ using combined acoustic and optical measurements
Studying the dynamics and geochemical behavior of dissolved and particulate organic material is difficult because concentration and composition may rapidly change in response to aperiodic as well as periodic physical and biological forcing. Here we describe a method useful for quantifying fluxes and analyzing dissolved organic matter (DOM) dynamics. The method uses coupled optical and acoustic mea
Authors
B.D. Downing, E. Boss, B.A. Bergamaschi, J.A. Fleck, M. A. Lionberger, N. K. Ganju, D. H. Schoellhamer, R. Fujii
High-frequency in situ optical measurements during a storm event: Assessing relationships between dissolved organic matter, sediment concentrations, and hydrologic processes
Dissolved organic matter (DOM) dynamics during storm events has received considerable attention in forested watersheds, but the extent to which storms impart rapid changes in DOM concentration and composition in highly disturbed agricultural watersheds remains poorly understood. In this study, we used identical in situ optical sensors for DOM fluorescence (FDOM) with and without filtration to cont
Authors
John Franco Saraceno, Brian A. Pellerin, Bryan D. Downing, Emmanuel Boss, Philip A. M. Bachand, Brian A. Bergamaschi
Assessing contribution of DOC from sediments to a drinking-water reservoir using optical profiling
Understanding the sources of dissolved organic carbon (DOC) in drinking-water reservoirs is an important management issue because DOC may form disinfection by-products, interfere with disinfection, or increase treatment costs. DOC may be derived from a host of sources-algal production of DOC in the reservoir, marginal production of DOC from mucks and vascular plants at the margins, and sediments i
Authors
Bryan D. Downing, Brian A. Bergamaschi, David G. Evans, Emmanuel Boss
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 38
Optical techniques for the determination of nitrate in environmental waters: Guidelines for instrument selection, operation, deployment, maintenance, quality assurance, and data reporting
The recent commercial availability of in situ optical sensors, together with new techniques for data collection and analysis, provides the opportunity to monitor a wide range of water-quality constituents on time scales in which environmental conditions actually change. Of particular interest is the application of ultraviolet (UV) photometers for in situ determination of nitrate concentrations in
Authors
Brian A. Pellerin, Brian A. Bergamaschi, Bryan D. Downing, John Franco Saraceno, Jessica D. Garrett, Lisa D. Olsen
Sources and characteristics of organic matter in the Clackamas River, Oregon, related to the formation of disinfection by-products in treated drinking water
This study characterized the amount and quality of organic matter in the Clackamas River, Oregon, to gain an understanding of sources that contribute to the formation of chlorinated and brominated disinfection by-products (DBPs), focusing on regulated DBPs in treated drinking water from two direct-filtration treatment plants that together serve approximately 100,000 customers. The central hypothes
Authors
Kurt D. Carpenter, Tamara E.C. Kraus, Jami H. Goldman, John Franco Saraceno, Bryan D. Downing, Brian A. Bergamaschi, Gordon McGhee, Tracy Triplett
Mercury dynamics in a San Francisco estuary tidal wetland: assessing dynamics using in situ measurements
We used high-resolution in situ measurements of turbidity and fluorescent dissolved organic matter (FDOM) to quantitatively estimate the tidally driven exchange of mercury (Hg) between the waters of the San Francisco estuary and Browns Island, a tidal wetland. Turbidity and FDOM—representative of particle-associated and filter-passing Hg, respectively—together predicted 94 % of the observed variab
Authors
Brian A. Bergamaschi, Jacob A. Fleck, Bryan D. Downing, Emmanuel Boss, Brian A. Pellerin, Neil K. Ganju, David H. Schoellhamer, Amy A. Byington, Wesley A. Heim, Mark Stephenson, Roger Fujii
Seeing the light: the effects of particles, dissolved materials, and temperature on in situ measurements of DOM fluorescence in rivers and streams
Field-deployable sensors designed to continuously measure the fluorescence of colored dissolved organic matter (FDOM) in situ are of growing interest. However, the ability to make FDOM measurements that are comparable across sites and over time requires a clear understanding of how instrument characteristics and environmental conditions affect the measurements. In particular, the effects of water
Authors
Bryan D. Downing, Brian A. Pellerin, Brian A. Bergamaschi, John Franco Saraceno, Tamara E.C. Kraus
Methyl mercury dynamics in a tidal wetland quantified using in situ optical measurements
We assessed monomethylmercury (MeHg) dynamics in a tidal wetland over three seasons using a novel method that employs a combination of in situ optical measurements as concentration proxies. MeHg concentrations measured over a single spring tide were extended to a concentration time series using in situ optical measurements. Tidal fluxes were calculated using modeled concentrations and bi-direction
Authors
B.A. Bergamaschi, J.A. Fleck, B.D. Downing, E. Boss, B. Pellerin, N. K. Ganju, D. H. Schoellhamer, A.A. Byington, W.A. Heim, M. Stephenson, R. Fujii
The aquatic real-time monitoring network; in-situ optical sensors for monitoring the nation's water quality
Floods, hurricanes, and longer-term changes in climate and land use can have profound effects on water quality due to shifts in hydrologic flow paths, water residence time, precipitation patterns, connectivity between rivers and uplands, and many other factors. In order to understand and respond to changes in hydrology and water quality, resource managers and policy makers have a need for accurate
Authors
Brian A. Pellerin, Brian A. Bergamaschi, Peter S. Murdoch, Bryan D. Downing, John Franco Saraceno, George R. Aiken, Robert G. Striegl
How reservoirs alter drinking water quality: Organic matter sources, sinks, and transformations
Within reservoirs, production, transformation, and loss of dissolved organic matter (DOM) occur simultaneously. While the balance between production and loss determines whether a reservoir is a net sink or source of DOM, changes in chemical composition are also important because they affect DOM reactivity with respect to disinfection by-product (DBP) formation. The composition of the DOM pool also
Authors
Tamara E.C. Kraus, Brian A. Bergamaschi, Peter J. Hernes, Daniel H. Doctor, Carol Kendall, Bryan D. Downing, Richard F. Losee
Determining sources of dissolved organic carbon and disinfection byproduct precursors to the McKenzie River, Oregon
This study was conducted to determine the main sources of dissolved organic carbon (DOC) and disinfection byproduct (DBP) precursors to the McKenzie River, Oregon (USA). Water samples collected from the mainstem, tributaries, and reservoir outflows were analyzed for DOC concentration and DBP formation potentials (trihalomethanes [THMFPs] and haloacetic acids [HAAFPs]). In addition, optical propert
Authors
Tamara E.C. Kraus, Chauncey W. Anderson, Karl Morgenstern, Bryan D. Downing, Brian A. Pellerin, Brian A. Bergamaschi
Assessing the sources and magnitude of diurnal nitrate variability in the San Joaquin River (California) with an in situ optical nitrate sensor and dual nitrate isotopes
1. We investigated diurnal nitrate (NO3−) concentration variability in the San Joaquin River using an in situ optical NO3− sensor and discrete sampling during a 5‐day summer period characterized by high algal productivity. Dual NO3− isotopes (δ15NNO3 and δ18ONO3) and dissolved oxygen isotopes (δ18ODO) were measured over 2 days to assess NO3− sources and biogeochemical controls over diurnal time‐sc
Authors
Brian A. Pellerin, Bryan D. Downing, Carol Kendall, Randy A. Dahlgren, Tamara E.C. Kraus, John Franco Saraceno, Robert G. M. Spencer, Brian A. Bergamaschi
Quantifying fluxes and characterizing compositional changes of dissolved organic matter in aquatic systems in situ using combined acoustic and optical measurements
Studying the dynamics and geochemical behavior of dissolved and particulate organic material is difficult because concentration and composition may rapidly change in response to aperiodic as well as periodic physical and biological forcing. Here we describe a method useful for quantifying fluxes and analyzing dissolved organic matter (DOM) dynamics. The method uses coupled optical and acoustic mea
Authors
B.D. Downing, E. Boss, B.A. Bergamaschi, J.A. Fleck, M. A. Lionberger, N. K. Ganju, D. H. Schoellhamer, R. Fujii
High-frequency in situ optical measurements during a storm event: Assessing relationships between dissolved organic matter, sediment concentrations, and hydrologic processes
Dissolved organic matter (DOM) dynamics during storm events has received considerable attention in forested watersheds, but the extent to which storms impart rapid changes in DOM concentration and composition in highly disturbed agricultural watersheds remains poorly understood. In this study, we used identical in situ optical sensors for DOM fluorescence (FDOM) with and without filtration to cont
Authors
John Franco Saraceno, Brian A. Pellerin, Bryan D. Downing, Emmanuel Boss, Philip A. M. Bachand, Brian A. Bergamaschi
Assessing contribution of DOC from sediments to a drinking-water reservoir using optical profiling
Understanding the sources of dissolved organic carbon (DOC) in drinking-water reservoirs is an important management issue because DOC may form disinfection by-products, interfere with disinfection, or increase treatment costs. DOC may be derived from a host of sources-algal production of DOC in the reservoir, marginal production of DOC from mucks and vascular plants at the margins, and sediments i
Authors
Bryan D. Downing, Brian A. Bergamaschi, David G. Evans, Emmanuel Boss