Victoria Glenn Christensen, PhD
Dr. Christensen is a research hydrologist who studies HABs, algal toxins, and cyanobacteria. She is a member of the Environmental Health Program's Algal Toxin Team and serves as the acting Communications Coordinator for the Water Mission Area.
Victoria Christensen studies cyanotoxins, with a focus on the neurotoxins, anatoxin-a and saxitoxin. Cyanotoxins are produced by cyanobacterial harmful alglal blooms (HABs), which are sometimes called blue-green algae. Her master’s research examined the occurrence and fate of dissolved solids, nutrients, atrazine, and bacteria in an agricultural watershed. Her dissertation research focused on cyanotoxin mixtures with an emphasis neurotoxins—looking at the environmental variables like wind and temperature that may trigger cyanobacteria to produce or release toxins. In addition to the study of harmful algae and their toxins, Victoria's interests and project work include real-time water-quality monitoring, effects of land use on water quality, the fate of nutrients in agricultural and reservoir systems. She also has an interest in writing and communicating science topics to broad audiences and is a trainer and USGS Subject Matter Expert on Scientific Project Management.
Professional Experience
Dr. Christensen has been working for the USGS for over twenty years and has experience in water quality, water-level management, and has done extensive research on cyanotoxins, harmful algal blooms, and nutrients. Prior to working for the USGS, she held positions with University of Kansas, Twin Cities Testing, and 3M Corporation.
Education and Certifications
PhD, Environmental and Conservation Science, North Dakota State University
MS, Water Resources Science, Dept. of Engineering, University of Kansas
BS, Geology, University of Kansas
BA, Management, Hamline University
Science and Products
Complex response of sediment phosphorus to land use and management within a river network
Denitrification in the river network of a mixed land use watershed: Unpacking the complexities
Techniques for estimating the magnitude and frequency of peak flows on small streams in the binational U.S. and Canadian Lake of the Woods–Rainy River Basin upstream from Kenora, Ontario, Canada, based on data through water year 2013
Sediment oxygen demand: A review of in situ methods
A history of trade routes and water-level regulation on waterways in Voyageurs National Park, Minnesota, USA
Voyageurs National Park: Water-level regulation and effects on water quality and aquatic biology
Mercury and water level fluctuations in lakes of northern Minnesota
Lake levels and water quality in comparison to fish mercury body burdens, Voyageurs National Park, Minnesota, 2013–15
Migratory bird habitat in relation to tile drainage and poorly drained hydrologic soil groups
Discharge and nutrient transport between lakes in a hydrologically complex area of Voyageurs National Park, Minnesota, 2010-2012
Trophic state in Voyageurs National Park lakes before and after implementation of a revised water-level management plan
Stream sediment sources in midwest agricultural basins with land retirement along channel
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Complex response of sediment phosphorus to land use and management within a river network
Rivers affected by anthropogenic nutrient inputs can retain some of the phosphorus (P) load through sediment retention and burial. Determining the influence of land use and management on sediment P concentrations and P retention in fluvial ecosystems is challenging because of different stressors operating at multiple spatial and temporal scales. In this study, we sought to determine how land use aAuthorsRebecca Kreiling, Martin C. Thoms, Lynn A. Bartsch, William B. Richardson, Victoria G. ChristensenDenitrification in the river network of a mixed land use watershed: Unpacking the complexities
River networks have the potential to permanently remove nitrogen through denitrification. Few studies have measured denitrification rates within an entire river network or assessed how land use affect rates at larger spatial scales. We sampled 108 sites throughout the network of the Fox River watershed, Wisconsin, to determine if land use influence sediment denitrification rates, and to identify zAuthorsRebecca Kreiling, William B. Richardson, Lynn A. Bartsch, Martin C. Thoms, Victoria G. ChristensenTechniques for estimating the magnitude and frequency of peak flows on small streams in the binational U.S. and Canadian Lake of the Woods–Rainy River Basin upstream from Kenora, Ontario, Canada, based on data through water year 2013
A binational study was initiated to update statistical equations that are used to estimate the magnitude and frequency of peak flows on streams in Manitoba and Ontario, Canada, and Minnesota that are contained within the binational Lake of the Woods–Rainy River Basin upstream from Kenora, Ontario, Canada. Hydraulic engineers use peak streamflow data to inform designs of bridges, culverts, and damsAuthorsChristopher A. Sanocki, Tara J. Williams-Sether, Peter A. Steeves, Victoria G. ChristensenSediment oxygen demand: A review of in situ methods
Sediment oxygen demand (SOD) plays a fundamental role in biological and chemical processes within the benthic layer of a water body. Land use, including agricultural land use, can affect SOD. However, a wide variety of approaches have been used for in situ SOD chamber construction and data collection, and modelers frequently use SOD values from the literature, without consideration of the differenAuthorsErin N. Coenen, Victoria G. Christensen, Lynn Bartsch, Rebecca Kreiling, William B. RichardsonA history of trade routes and water-level regulation on waterways in Voyageurs National Park, Minnesota, USA
Unlike most national parks, main access to Voyageurs National Park is by boat. This remote system of interconnected waterways along the USA-Canada border was an important transportation route for thousands of years of American Indian occupation, leading up to and including the trade route of the voyageurs, or French-Canadian fur traders from around 1680 to 1870. The Ojibwe people collaborated withAuthorsVictoria G. Christensen, Andrew E. LaBountyVoyageurs National Park: Water-level regulation and effects on water quality and aquatic biology
Following dam installations in the remote Rainy Lake Basin during the early 1900s, water-level fluctuations were considered extreme (1914–1949) compared to more natural conditions. In 1949, the International Joint Commission (IJC), which sets rules governing dam operation on waters shared by the United States and Canada, established the first rule curves to regulate water levels on these waterbodiAuthorsVictoria G. Christensen, Ryan P. Maki, Jaime F. LeDucMercury and water level fluctuations in lakes of northern Minnesota
Large lake ecosystems support a variety of ecosystem services in surrounding communities, including recreational and commercial fishing. However, many northern temperate fisheries are contaminated by mercury. Annual variation in mercury accumulation in fish has previously been linked to water level (WL) fluctuations, opening the possibility of regulating water levels in a manner that minimizes orAuthorsJames H. Larson, Ryan P. Maki, Victoria G. Christensen, Mark B. Sandheinrich, Jaime F. LeDuc, Claire Kissane, Brent C. KnightsLake levels and water quality in comparison to fish mercury body burdens, Voyageurs National Park, Minnesota, 2013–15
Within Voyageurs National Park in Minnesota, lake levels are controlled by a series of dams to support a variety of uses. Previous research indicates a link between these artificially maintained water levels, referred to as rule curves, and mercury concentrations in fish owing to the drying and rewetting of wetlands and other nearshore areas, which may release methylmercury into the water when inuAuthorsVictoria G. Christensen, James H. Larson, Ryan P. Maki, Mark B. Sandheinrich, Mark E. Brigham, Claire Kissane, Jamie F. LeDucMigratory bird habitat in relation to tile drainage and poorly drained hydrologic soil groups
The Prairie Pothole Region (PPR) is home to more than 50% of the migratory waterfowl in North America. Although the PPR provides an abundance of temporary and permanent wetlands for nesting and feeding, increases in commodity prices and agricultural drainage practices have led to a trend of wetland drainage. The Northern Shoveler is a migratory dabbling duck species that uses wetland habitats andAuthorsBrandi Kastner, Victoria G. Christensen, Tanja N. Williamson, Christopher A. SanockiDischarge and nutrient transport between lakes in a hydrologically complex area of Voyageurs National Park, Minnesota, 2010-2012
An acoustic Doppler velocity meter (ADVM) was deployed in the narrows between Namakan and Kabetogama Lakes in Voyageurs National Park, Minnesota, from November 3, 2010, through October 3, 2012. The ADVM can account for wind, seiche, and changing flow direction in hydrologically complex areas. The objectives were to (1) estimate discharge and document the direction of water flow, (2) assess whetherAuthorsVictoria G. Christensen, Eric Wakeman, Ryan P. MakiTrophic state in Voyageurs National Park lakes before and after implementation of a revised water-level management plan
We compiled Secchi depth, total phosphorus, and chlorophyll a (Chla) data from Voyageurs National Park lakes and compared datasets before and after a new water-level management plan was implemented in January 2000. Average Secchi depth transparency improved (from 1.9 to 2.1 m, p = 0.020) between 1977-1999 and 2000-2011 in Kabetogama Lake for August samples only and remained unchanged in Rainy, NamAuthorsVictoria G. Christensen, Ryan P. MakiStream sediment sources in midwest agricultural basins with land retirement along channel
Documenting the effects of agricultural land retirement on stream-sediment sources is critical to identifying management practices that improve water quality and aquatic habitat. Particularly difficult to quantify are the effects from conservation easements that commonly are discontinuous along channelized streams and ditches throughout the agricultural midwestern United States. Our hypotheses werAuthorsTanja N. Williamson, Victoria G. Christensen, William B. Richardson, Jeffrey W. Frey, Allen C. Gellis, K. A. Kieta, Faith A. Fitzpatrick - News