Jacob M Ogorek
Biography
EDUCATION
M.S., Biology-Aquatic Science, UW-LaCrosse, 2009
B.S., Biology-Aquatic Science, Minor in Chemistry, UW-LaCrosse 2004
AREAS OF EXPERTISE
- Methyl and Total Mercury Analysis in Solid and Aqueous Matrices
CURRENT PROJECTS
- Mercury Cycling and Bioaccumulation in the Great Lakes
- Sediment Methylmercury Concentrations and Production Rates in Chequamegon Bay (WI), Lake Superior
Science and Products
The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin
Past industrial use and subsequent release of mercury (Hg) into the environment have resulted in severe cases of legacy contamination that still influence contemporary Hg levels in biota. While the bioaccumulation of legacy Hg is commonly assessed via concentration measurements within fish tissue, this practice becomes difficult in regions of high...
Janssen, Sarah E.; Tate, Michael T.; Krabbenhoft, David P.; DeWild, John F.; Ogorek, Jacob M.; Babiarz, Christopher L.; Sowers, Anthony; Tuttle, Peter L. Isolation of methylmercury using distillation and anion-exchange chromatography for isotopic analyses in natural matrices
The development of mercury (Hg) stable isotope measurements has enhanced the study of Hg sources and transformations in the environment. As a result of the mixing of inorganic Hg (iHg) and methylmercury (MeHg) species within organisms of the aquatic food web, understanding species-specific Hg stable isotopic compositions is of significant...
Rosera, Tylor; Janssen, Sarah E.; Tate, Michael T.; Lepak, Ryan F.; Ogorek, Jacob M.; DeWild, John F.; Babiarz, Christopher L.; Krabbenhoft, David P.; Hurley, James P. Mercury source changes and food web shifts alter contamination signatures of predatory fish from Lake Michigan
To understand the impact reduced mercury (Hg) loading and invasive species have had on methylmercury bioaccumulation in predator fish of Lake Michigan, we reconstructed bioaccumulation trends from a fish archive (1978 to 2012). By measuring fish Hg stable isotope ratios, we related temporal changes in Hg concentrations to varying Hg sources....
Lepak, Ryan F.; Hoffman, Joel C.; Janssen, Sarah E.; Krabbenhoft, David P.; Ogorek, Jacob M.; DeWild, John F.; Tate, Michael T.; Babiarz, Christopher L.; Yin, Runsheng; Murphy, Elizabeth W; Engstrom, Daniel R; Hurley, James P. Chemical and physical controls on mercury source signatures in stream fish from the northeastern United States
Streams in the northeastern U.S. receive mercury (Hg) in varying proportions from atmospheric deposition and legacy point sources, making it difficult to attribute shifts in fish concentrations directly back to changes in Hg source management. Mercury stable isotope tracers were utilized to relate sources of Hg to co-located fish and bed sediments...
Janssen, Sarah E.; Riva-Murray, Karen; DeWild, John F.; Ogorek, Jacob M.; Tate, Michael T.; Van Metre, Peter C.; Krabbenhoft, David P.; Coles, James F.
Biogeochemical and physical processes controlling mercury methylation and bioaccumulation in Lake Powell, Glen Canyon National Recreation Area, Utah and Arizona, 2014 and 2015
Mercury monitoring results from about 300 Morone saxatilis (striped bass) muscle tissue samples collected by the State of Utah from Lake Powell resulted in a Utah/Arizona fish consumption advisory issued in 2012 for approximately the lower 100 kilometers of the reservoir. Chemical, physical, and biological data were collected during two synoptic...
Naftz, David L.; Marvin-DiPasquale, Mark; Krabbenhoft, David P.; Aiken, George; Boyd, Eric S.; Conaway, Christopher H.; Ogorek, Jacob M.; Anderson, Gregory M. Rapid pre-concentration of mercury in solids and water for isotopic analysis
The precise quantification of mercury (Hg) stable isotope compositions in low concentration or dilute samples poses analytical challenges due to Hg mass limitations. Common Hg pre-concentration procedures require extended processing times, making rapid Hg stable isotope measurements challenging. Here we present a modified pre-...
Janssen, Sarah E.; Lepak, Ryan F.; Tate, Michael T.; Ogorek, Jacob M.; DeWild, John F.; Babiarz, Christopher L.; Hurley, James P.; Krabbenhoft, David P. Mercury isotopes reveal an ontogenetic shift in habitat use by walleye in lower Green Bay of Lake Michigan
In general, fish residing in rivers differ from fish residing in lakes in their mercury (Hg) isotope ratios. Specifically, fish residing in lakes typically show enriched values for the isotope ratios of δ202Hg (mass-dependent fractionation of isotope 202Hg) and Δ199Hg (mass-independent fractionation of isotope 199Hg) compared with fish...
Madenjian, Charles P.; Janssen, Sarah E.; Lepak, Ryan F.; Ogorek, Jacob M.; Rosera, Tylor J.; DeWild, John F.; Krabbenhoft, David P.; Cogswell, Stewart F.; Holey, Mark E. Ratio of mercury concentration to PCB concentration varies with sex of white sucker (Catostomus commersonii)
The whole-fish total mercury (Hg) concentrations were determined in 25 mature female and 26 mature male white suckers (Catostomus commersonii) caught during their spawning run in the Kewaunee River, a tributary to Lake Michigan. The age of each fish was estimated using thin-sectioned otoliths, and total length (TL) and weight were determined for...
Madenjian, Charles P.; Stevens, Andrew L.; Stapanian, Martin A.; Krabbenhoft, David P.; DeWild, John F.; Ogorek, Jacob M.; Edwards, William H.; Ogilvie, Lynn M.; McIntyre, Peter B. Factors affecting mercury stable isotopic distribution in piscivorous fish of the Laurentian Great Lakes
Identifying the sources of methylmercury (MeHg) and tracing the transformations of mercury (Hg) in the aquatic food web are important components of effective strategies for managing current and legacy Hg sources. In our previous work, we measured stable isotopes of Hg (δ202Hg, Δ199Hg, and Δ200Hg) in the Laurentian Great Lakes and estimated source...
Janssen, Sarah E.; Yin, Runsheng; Ogorek, Jacob M.; DeWild, John F.; Tate, Michael T.; Holsen, Thomas M.; Hurley, James P.; Lepak, Ryan F.; Janssen, Sarah E.; Yin, Runsheng; Krabbenhoft, David P.; Ogorek, Jacob M.; DeWild, John F.; Tate, Michael T.; Holsen, Thomas M.; Hurley, James P. Mercury accumulation and the mercury-PCB-sex interaction in summer flounder
Patterns in the relative differences in contaminant concentrations between the sexes of mature fish may reveal important behavioral and physiological differences between the sexes. We determined whole-fish total mercury (Hg) concentrations in 23 female summer flounder (Paralichthys dentatus) and 27 male summer flounder from New Jersey coastal...
Madenjian, Charles P.; Jensen, Olaf P.; Krabbenhoft, David P.; DeWild, John F.; Ogorek, Jacob M.; Vastano, Anthony R. The effect of natural organic matter on mercury methylation by Desulfobulbus propionicus 1pr3
Methylation of tracer and ambient mercury (200Hg and 202Hg, respectively) equilibrated with four different natural organic matter (NOM) isolates was investigated in vivo using the Hg-methylating sulfate-reducing bacterium Desulfobulbus propionicus 1pr3. Desulfobulbus cultures grown fermentatively with...
Moreau, John W.; Gionfriddo, Caitlin M.; Krabbenhoft, David P.; Ogorek, Jacob M.; DeWild, John F.; Aiken, George R.; Roden, Eric E. Use of stable isotope signatures to determine mercury sources in the Great Lakes
Sources of mercury (Hg) in Great Lakes sediments were assessed with stable Hg isotope ratios using multicollector inductively coupled plasma mass spectrometry. An isotopic mixing model based on mass-dependent (MDF) and mass-independent fractionation (MIF) (δ202Hg and Δ199Hg) identified three primary Hg sources for sediments:...
Lepak, Ryan F.; Yin, Runsheng; Krabbenhoft, David P.; Ogorek, Jacob M.; DeWild, John F.; Holsen, Thomas M.; Hurley, James P.