Jacob M Ogorek
Jacob Ogorek is a Biologist with the Upper Midwest Water Science Center.
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
Education and Certifications
M.S., Biology-Aquatic Science, UW-LaCrosse, 2009
B.S., Biology-Aquatic Science, Minor in Chemistry, UW-LaCrosse 2004
Science and Products
Filter Total Items: 19
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 residing in rivers, because photochemical effects acting on Hg
Authors
Charles P. Madenjian, Sarah E. Janssen, Ryan F. Lepak, Jacob M. Ogorek, Tylor J. Rosera, John F. DeWild, David P. Krabbenhoft, Stewart F. Cogswell, Mark E. Holey
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 each fish. When adjusted for the effect of age, male
Authors
Charles P. Madenjian, Andrew L. Stevens, Martin A. Stapanian, David P. Krabbenhoft, John F. DeWild, Jacob M. Ogorek, William H. Edwards, Lynn M. Ogilvie, Peter B. McIntyre
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 contributions of Hg to bottom sediment. Here, we id
Authors
Ryan F. Lepak, Sarah E. Janssen, Runsheng Yin, Jacob M. Ogorek, David P. Krabbenhoft, John F. DeWild, Michael T. Tate, Thomas M. Holsen, James P. Hurley
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 waters. To estimate the change in Hg concentration due
Authors
Charles P. Madenjian, Olaf P. Jensen, David P. Krabbenhoft, John F. DeWild, Jacob M. Ogorek, Anthony R. Vastano
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 environmentally representative concentrations of dissolved NOM isolates, Hg[II], and HS− were ass
Authors
John W. Moreau, Caitlin M. Gionfriddo, David P. Krabbenhoft, Jacob M. Ogorek, John F. DeWild, George R. Aiken, Eric E. Roden
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: atmospheric, industrial, and watershed-derived. Results indicate atmosphe
Authors
Ryan F. Lepak, Runsheng Yin, David P. Krabbenhoft, Jacob M. Ogorek, John F. DeWild, Thomas M. Holsen, James P. Hurley
Determination of Antimycin-A in water by liquid chromatographic/mass spectrometry: single-laboratory validation
An LC/MS method was developed and validated for the quantitative determination and confirmation of antimycin-A (ANT-A) in water from lakes or streams. Three different water sample volumes (25, 50, and 250 mL) were evaluated. ANT-A was stabilized in the field by immediately extracting it from water into anhydrous acetone using SPE. The stabilized concentrated samples were then transported to a labo
Authors
Jeffry A. Bernardy, Terrance D. Hubert, Jacob M. Ogorek, Larry J. Schmidt
Science and Products
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- Publications
Filter Total Items: 19
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 residing in rivers, because photochemical effects acting on HgAuthorsCharles P. Madenjian, Sarah E. Janssen, Ryan F. Lepak, Jacob M. Ogorek, Tylor J. Rosera, John F. DeWild, David P. Krabbenhoft, Stewart F. Cogswell, Mark E. HoleyRatio 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 each fish. When adjusted for the effect of age, maleAuthorsCharles P. Madenjian, Andrew L. Stevens, Martin A. Stapanian, David P. Krabbenhoft, John F. DeWild, Jacob M. Ogorek, William H. Edwards, Lynn M. Ogilvie, Peter B. McIntyreFactors 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 contributions of Hg to bottom sediment. Here, we idAuthorsRyan F. Lepak, Sarah E. Janssen, Runsheng Yin, Jacob M. Ogorek, David P. Krabbenhoft, John F. DeWild, Michael T. Tate, Thomas M. Holsen, James P. HurleyMercury 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 waters. To estimate the change in Hg concentration dueAuthorsCharles P. Madenjian, Olaf P. Jensen, David P. Krabbenhoft, John F. DeWild, Jacob M. Ogorek, Anthony R. VastanoThe 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 environmentally representative concentrations of dissolved NOM isolates, Hg[II], and HS− were assAuthorsJohn W. Moreau, Caitlin M. Gionfriddo, David P. Krabbenhoft, Jacob M. Ogorek, John F. DeWild, George R. Aiken, Eric E. RodenUse 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: atmospheric, industrial, and watershed-derived. Results indicate atmospheAuthorsRyan F. Lepak, Runsheng Yin, David P. Krabbenhoft, Jacob M. Ogorek, John F. DeWild, Thomas M. Holsen, James P. HurleyDetermination of Antimycin-A in water by liquid chromatographic/mass spectrometry: single-laboratory validation
An LC/MS method was developed and validated for the quantitative determination and confirmation of antimycin-A (ANT-A) in water from lakes or streams. Three different water sample volumes (25, 50, and 250 mL) were evaluated. ANT-A was stabilized in the field by immediately extracting it from water into anhydrous acetone using SPE. The stabilized concentrated samples were then transported to a laboAuthorsJeffry A. Bernardy, Terrance D. Hubert, Jacob M. Ogorek, Larry J. Schmidt