Victoria Glenn Christensen, PhD (Former Employee)
Science and Products
National Water-Quality Project Sampling Methods
USGS National Water Quality Assessment (NAWQA) studies require analyses of stream and bed-sediment samples for major ions, nutrients, sediments, and organic contaminants that are consistent across time and space. Procedures have been designed specifically to produce information that is comparable among studies in different parts of the Nation.
Algal toxins and Mycobacterium avium ssp. paratuberculosis measured in surface-water, quarry-water, and sediment samples collected at Pipestone National Monument, Pipestone, Minnesota, 2018-19 Algal toxins and Mycobacterium avium ssp. paratuberculosis measured in surface-water, quarry-water, and sediment samples collected at Pipestone National Monument, Pipestone, Minnesota, 2018-19
The U.S. Geological Survey, in cooperation with the U.S. National Park Service, conducted a study to determine the presence of algal toxins and Mycobacterium avium ssp. paratuberculosis (MAP) within Pipestone National Monument located in Pipestone County in southwestern Minnesota. Three algal toxins (microcystins, saxitoxin, and anatoxin-a) were analyzed in 12 water-quality samples...
Data and model archive for multiple linear regression models for prediction of weighted cyanotoxin mixture concentrations and microcystin concentrations at three recurring bloom sites in Kabetogama Lake in Minnesota Data and model archive for multiple linear regression models for prediction of weighted cyanotoxin mixture concentrations and microcystin concentrations at three recurring bloom sites in Kabetogama Lake in Minnesota
Multiple linear regression models were developed using data collected in 2016 and 2017 from three recurring bloom sites in Kabetogama Lake in northern Minnesota. These models were developed to predict concentrations of cyanotoxins (anatoxin-a, microcystin, and saxitoxin) that occur within the blooms. Virtual Beach software (version 3.0.6) was used to develop four models: two cyanotoxin...
Chemical and physical data for sediment source fingerprinting of suspended and bottom sediment in the West Fork of Beaver Creek, Minnesota Chemical and physical data for sediment source fingerprinting of suspended and bottom sediment in the West Fork of Beaver Creek, Minnesota
This data release includes physical and chemical data for samples from suspended and bottom sediments of streams in Minnesota. Data were collected in September 2011 and April 2012. These data include total nitrogen and carbon, organic carbon, concentrations for 39 metals, and particle-size analysis. Source samples were grouped into one of three land-use categories: channel (Mid-bank,Low...
Rapid assessment test strip data for determining cyanotoxin presence in algal blooms, Kabetogama Lake, northern Minnesota, 2017-2018 Rapid assessment test strip data for determining cyanotoxin presence in algal blooms, Kabetogama Lake, northern Minnesota, 2017-2018
Algal toxins are a growing concern worldwide. Rapid assessment test strips are a newer technology and their accuracy in detecting toxins in different lakes with different phytoplankton and toxins present is unknown. This data release is supported by our testing of toxin test strips. This research took place in Voyageurs National Park in northern Minnesota. The research will indicate...
Phytoplankton enumeration and identification from a recurring algal bloom location in Sullivan Bay, Kabetogama Lake, northern Minnesota, 2016 Phytoplankton enumeration and identification from a recurring algal bloom location in Sullivan Bay, Kabetogama Lake, northern Minnesota, 2016
This data release provides phytoplankton identification, phytoplankton enumeration, chlorophyll concentration, phaeophytin concentration, phycocyanin data, and nutrient quality assurance data from three recurring algal bloom sites in Kabetogama Lake, Voyaguers National Park, Minnesota in 2016 and 2017. The goal of this research is to better understand the drivers of algal bloom toxicity...
Filter Total Items: 52
Phytoplankton community interactions and cyanotoxin mixtures in three recurring surface blooms within one lake Phytoplankton community interactions and cyanotoxin mixtures in three recurring surface blooms within one lake
Cyanobacteria can produce numerous secondary metabolites (cyanotoxins) with various toxicities, yet data on cyanotoxins in many lakes are limited. Moreover, little research is available on complex relations among cyanobacteria that produce toxins. Therefore, we studied cyanobacteria and 19 cyanotoxins at three sites with recurring blooms in Kabetogama Lake (USA). Seven of 19 toxins were...
Authors
Victoria Christensen, Hayley T. Olds, Jack E. Norland, Eakalak Khan
A review of algal toxin exposures on reserved federal lands and among trust species in the United States A review of algal toxin exposures on reserved federal lands and among trust species in the United States
Associated health effects from algal toxin exposure are a growing concern for human and animal health. Algal toxin poisonings may occur from contact with or consumption of water supplies or from ingestion of contaminated animals. The U.S. Federal Government owns or holds in trust about 259 million hectares of land, in addition to the Trust species obligations. We completed the first...
Authors
Zachary R. Laughrey, Victoria Christensen, Robert J. Dusek, Sarena Senegal, Julia S. Lankton, Tracy Ziegler, Lee C. Jones, Daniel K. Jones, Brianna Williams, Stephanie E. Gordon, Gerald A. Clyde, Erich B Emery, Keith A. Loftin
Riparian forest cover modulates phosphorus storage and nitrogen cycling in agricultural stream sediments Riparian forest cover modulates phosphorus storage and nitrogen cycling in agricultural stream sediments
Watershed land cover affects in-stream water quality and sediment nutrient dynamics. The presence of natural land cover in the riparian zone can reduce the negative effects of agricultural land use on water quality; however, literature evaluating the effects of natural riparian land cover on stream sediment nutrient dynamics is scarce. The objective of this study was to assess if stream...
Authors
Rebecca M. Kreiling, Lynn A. Bartsch, Patrik Mathis Perner, Enrika Hlavacek, Victoria Christensen
Freshwater cyanotoxin mixtures in recurring cyanobacterial blooms in Voyageurs National Park Freshwater cyanotoxin mixtures in recurring cyanobacterial blooms in Voyageurs National Park
Algal and cyanobacterial blooms can foul water systems, inhibit recreation, and produce cyanotoxins, which can be toxic to humans, domestic animals, and wildlife. Blooms that recur yearly present a special challenge, in that chronic effects of most cyanotoxins are unknown. To better understand cyanotoxin timing, possible environmental triggers, and inter-relations among taxa and toxins...
Authors
Victoria Christensen
Mercury and water level management in lakes of northern Minnesota Mercury and water level management in lakes of northern Minnesota
Water level (WL) fluctuations substantially alter the fauna, flora, and microbial community of nearshore aquatic ecosystems. Water level management therefore has the potential to strongly influence a wide variety of ecosystem processes. Many northern temperate lake food webs experience substantial methylmercury contamination, which is partially mediated by the action of sulfate-reducing...
Authors
James H. Larson, Ryan P. Maki, Victoria Christensen, Enrika Hlavacek, Mark B. Sandheinrich, Jaime F. LeDuc, Claire Kissane, Brent C. Knights
Cyanotoxin mixture models: Relating environmental variables and toxin co-occurrence to human exposure risk Cyanotoxin mixture models: Relating environmental variables and toxin co-occurrence to human exposure risk
Toxic cyanobacterial blooms, often containing multiple toxins, are a serious public health issue. However, there are no known models that predict a cyanotoxin mixture (anatoxin-a, microcystin, saxitoxin). This paper presents two cyanotoxin mixture models (MIX) and compares them to two microcystin (MC) models from data collected in 2016–2017 from three recurring cyanobacterial bloom...
Authors
Victoria Christensen, Erin A. Stelzer, Barbara C. Scudder Eikenberry, Hayley T. Olds, Jaime F. LeDuc, Ryan P. Maki, Jack E. Norland, Eakalak Khan
Science and Products
National Water-Quality Project Sampling Methods
USGS National Water Quality Assessment (NAWQA) studies require analyses of stream and bed-sediment samples for major ions, nutrients, sediments, and organic contaminants that are consistent across time and space. Procedures have been designed specifically to produce information that is comparable among studies in different parts of the Nation.
Algal toxins and Mycobacterium avium ssp. paratuberculosis measured in surface-water, quarry-water, and sediment samples collected at Pipestone National Monument, Pipestone, Minnesota, 2018-19 Algal toxins and Mycobacterium avium ssp. paratuberculosis measured in surface-water, quarry-water, and sediment samples collected at Pipestone National Monument, Pipestone, Minnesota, 2018-19
The U.S. Geological Survey, in cooperation with the U.S. National Park Service, conducted a study to determine the presence of algal toxins and Mycobacterium avium ssp. paratuberculosis (MAP) within Pipestone National Monument located in Pipestone County in southwestern Minnesota. Three algal toxins (microcystins, saxitoxin, and anatoxin-a) were analyzed in 12 water-quality samples...
Data and model archive for multiple linear regression models for prediction of weighted cyanotoxin mixture concentrations and microcystin concentrations at three recurring bloom sites in Kabetogama Lake in Minnesota Data and model archive for multiple linear regression models for prediction of weighted cyanotoxin mixture concentrations and microcystin concentrations at three recurring bloom sites in Kabetogama Lake in Minnesota
Multiple linear regression models were developed using data collected in 2016 and 2017 from three recurring bloom sites in Kabetogama Lake in northern Minnesota. These models were developed to predict concentrations of cyanotoxins (anatoxin-a, microcystin, and saxitoxin) that occur within the blooms. Virtual Beach software (version 3.0.6) was used to develop four models: two cyanotoxin...
Chemical and physical data for sediment source fingerprinting of suspended and bottom sediment in the West Fork of Beaver Creek, Minnesota Chemical and physical data for sediment source fingerprinting of suspended and bottom sediment in the West Fork of Beaver Creek, Minnesota
This data release includes physical and chemical data for samples from suspended and bottom sediments of streams in Minnesota. Data were collected in September 2011 and April 2012. These data include total nitrogen and carbon, organic carbon, concentrations for 39 metals, and particle-size analysis. Source samples were grouped into one of three land-use categories: channel (Mid-bank,Low...
Rapid assessment test strip data for determining cyanotoxin presence in algal blooms, Kabetogama Lake, northern Minnesota, 2017-2018 Rapid assessment test strip data for determining cyanotoxin presence in algal blooms, Kabetogama Lake, northern Minnesota, 2017-2018
Algal toxins are a growing concern worldwide. Rapid assessment test strips are a newer technology and their accuracy in detecting toxins in different lakes with different phytoplankton and toxins present is unknown. This data release is supported by our testing of toxin test strips. This research took place in Voyageurs National Park in northern Minnesota. The research will indicate...
Phytoplankton enumeration and identification from a recurring algal bloom location in Sullivan Bay, Kabetogama Lake, northern Minnesota, 2016 Phytoplankton enumeration and identification from a recurring algal bloom location in Sullivan Bay, Kabetogama Lake, northern Minnesota, 2016
This data release provides phytoplankton identification, phytoplankton enumeration, chlorophyll concentration, phaeophytin concentration, phycocyanin data, and nutrient quality assurance data from three recurring algal bloom sites in Kabetogama Lake, Voyaguers National Park, Minnesota in 2016 and 2017. The goal of this research is to better understand the drivers of algal bloom toxicity...
Filter Total Items: 52
Phytoplankton community interactions and cyanotoxin mixtures in three recurring surface blooms within one lake Phytoplankton community interactions and cyanotoxin mixtures in three recurring surface blooms within one lake
Cyanobacteria can produce numerous secondary metabolites (cyanotoxins) with various toxicities, yet data on cyanotoxins in many lakes are limited. Moreover, little research is available on complex relations among cyanobacteria that produce toxins. Therefore, we studied cyanobacteria and 19 cyanotoxins at three sites with recurring blooms in Kabetogama Lake (USA). Seven of 19 toxins were...
Authors
Victoria Christensen, Hayley T. Olds, Jack E. Norland, Eakalak Khan
A review of algal toxin exposures on reserved federal lands and among trust species in the United States A review of algal toxin exposures on reserved federal lands and among trust species in the United States
Associated health effects from algal toxin exposure are a growing concern for human and animal health. Algal toxin poisonings may occur from contact with or consumption of water supplies or from ingestion of contaminated animals. The U.S. Federal Government owns or holds in trust about 259 million hectares of land, in addition to the Trust species obligations. We completed the first...
Authors
Zachary R. Laughrey, Victoria Christensen, Robert J. Dusek, Sarena Senegal, Julia S. Lankton, Tracy Ziegler, Lee C. Jones, Daniel K. Jones, Brianna Williams, Stephanie E. Gordon, Gerald A. Clyde, Erich B Emery, Keith A. Loftin
Riparian forest cover modulates phosphorus storage and nitrogen cycling in agricultural stream sediments Riparian forest cover modulates phosphorus storage and nitrogen cycling in agricultural stream sediments
Watershed land cover affects in-stream water quality and sediment nutrient dynamics. The presence of natural land cover in the riparian zone can reduce the negative effects of agricultural land use on water quality; however, literature evaluating the effects of natural riparian land cover on stream sediment nutrient dynamics is scarce. The objective of this study was to assess if stream...
Authors
Rebecca M. Kreiling, Lynn A. Bartsch, Patrik Mathis Perner, Enrika Hlavacek, Victoria Christensen
Freshwater cyanotoxin mixtures in recurring cyanobacterial blooms in Voyageurs National Park Freshwater cyanotoxin mixtures in recurring cyanobacterial blooms in Voyageurs National Park
Algal and cyanobacterial blooms can foul water systems, inhibit recreation, and produce cyanotoxins, which can be toxic to humans, domestic animals, and wildlife. Blooms that recur yearly present a special challenge, in that chronic effects of most cyanotoxins are unknown. To better understand cyanotoxin timing, possible environmental triggers, and inter-relations among taxa and toxins...
Authors
Victoria Christensen
Mercury and water level management in lakes of northern Minnesota Mercury and water level management in lakes of northern Minnesota
Water level (WL) fluctuations substantially alter the fauna, flora, and microbial community of nearshore aquatic ecosystems. Water level management therefore has the potential to strongly influence a wide variety of ecosystem processes. Many northern temperate lake food webs experience substantial methylmercury contamination, which is partially mediated by the action of sulfate-reducing...
Authors
James H. Larson, Ryan P. Maki, Victoria Christensen, Enrika Hlavacek, Mark B. Sandheinrich, Jaime F. LeDuc, Claire Kissane, Brent C. Knights
Cyanotoxin mixture models: Relating environmental variables and toxin co-occurrence to human exposure risk Cyanotoxin mixture models: Relating environmental variables and toxin co-occurrence to human exposure risk
Toxic cyanobacterial blooms, often containing multiple toxins, are a serious public health issue. However, there are no known models that predict a cyanotoxin mixture (anatoxin-a, microcystin, saxitoxin). This paper presents two cyanotoxin mixture models (MIX) and compares them to two microcystin (MC) models from data collected in 2016–2017 from three recurring cyanobacterial bloom...
Authors
Victoria Christensen, Erin A. Stelzer, Barbara C. Scudder Eikenberry, Hayley T. Olds, Jaime F. LeDuc, Ryan P. Maki, Jack E. Norland, Eakalak Khan