Christopher Mills
Christopher Mills is a Research Chemist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 23
Insights into controls on hexavalent chromium in groundwater provided by environmental tracers, Sacramento Valley, California, USA Insights into controls on hexavalent chromium in groundwater provided by environmental tracers, Sacramento Valley, California, USA
Environmental tracers are useful for determining groundwater age and recharge source, yet their application in studies of geogenic Cr(VI) in groundwater has been limited. Environmental tracer data from 166 wells located in the Sacramento Valley, northern California, were interpreted and compared to Cr concentrations to determine the origin and age of groundwater with elevated Cr(VI), and...
Authors
Andrew H. Manning, Christopher T. Mills, Jean M. Morrison, Lyndsay B. Ball
Hydrogeochemistry of prairie pothole region wetlands: Role of long-term critical zone processes Hydrogeochemistry of prairie pothole region wetlands: Role of long-term critical zone processes
This study addresses the geologic and hydrogeochemical processes operating at a range of scales within the prairie pothole region (PPR). The PPR is a 750,000 km2portion of north central North America that hosts millions of small wetlands known to be critical habitat for waterfowl and other wildlife. At a local scale, we characterized the geochemical evolution of the 92-ha Cottonwood Lake...
Authors
Martin B. Goldhaber, Christopher T. Mills, Jean M. Morrison, Craig A. Stricker, David M. Mushet, James W. LaBaugh
The relative contribution of methanotrophs to microbial communities and carbon cycling in soil overlying a coal-bed methane seep The relative contribution of methanotrophs to microbial communities and carbon cycling in soil overlying a coal-bed methane seep
Seepage of coal-bed methane (CBM) through soils is a potential source of atmospheric CH4 and also a likely source of ancient (i.e. 14C-dead) carbon to soil microbial communities. Natural abundance 13C and 14C compositions of bacterial membrane phospholipid fatty acids (PLFAs) and soil gas CO2 and CH4 were used to assess the incorporation of CBM-derived carbon into methanotrophs and other...
Authors
Christopher T. Mills, Gregory F. Slater, Robert F. Dias, Stephanie A. Carr, Christopher M. Reddy, Raleigh Schmidt, Kevin W. Mandernack
Laboratory investigations of the effects of nitrification-induced acidification on Cr cycling in vadose zone material partially derived from ultramafic rocks Laboratory investigations of the effects of nitrification-induced acidification on Cr cycling in vadose zone material partially derived from ultramafic rocks
Sacramento Valley (California, USA) soils and sediments have high concentrations of Cr(III) because they are partially derived from ultramafic material. Some Cr(III) is oxidized to more toxic and mobile Cr(VI) by soil Mn oxides. Valley soils typically have neutral to alkaline pH at which Cr(III) is highly immobile. Much of the valley is under cultivation and is both fertilized and...
Authors
Christopher T. Mills, Martin B. Goldhaber
Using stable isotopes to understand hydrochemical processes in and around a Prairie Pothole wetland in the Northern Great Plains, USA Using stable isotopes to understand hydrochemical processes in and around a Prairie Pothole wetland in the Northern Great Plains, USA
Millions of internally drained wetland systems in the Prairie Potholes region of the northern Great Plains (USA and Canada) provide indispensable habitat for waterfowl and a host of other ecosystem services. The hydrochemistry of these systems is complex and a crucial control on wetland function, flora and fauna. Wetland waters can have high concentrations of SO2-4 due to the oxidation...
Authors
Christopher T. Mills, Martin B. Goldhaber, Craig A. Stricker, JoAnn M. Holloway, Jean M. Morrison, Karl J. Ellefsen, Donald O. Rosenberry, Roland S. Thurston
The role of critical zone processes in the evolution of the Prairie Pothole Region wetlands The role of critical zone processes in the evolution of the Prairie Pothole Region wetlands
The Prairie Pothole Region, which occupies 900,000 km2 of the north central USA and south central Canada, is one of the most important ecosystems in North America. It is characterized by millions of small wetlands whose chemistry is highly variable over short distances. The study involved the geochemistry of surface sediments, wetland water, and groundwater in the Cottonwood Lakes area...
Authors
Martin B. Goldhaber, Christopher T. Mills, Craig A. Stricker, Jean M. Morrison
Science and Products
Filter Total Items: 23
Insights into controls on hexavalent chromium in groundwater provided by environmental tracers, Sacramento Valley, California, USA Insights into controls on hexavalent chromium in groundwater provided by environmental tracers, Sacramento Valley, California, USA
Environmental tracers are useful for determining groundwater age and recharge source, yet their application in studies of geogenic Cr(VI) in groundwater has been limited. Environmental tracer data from 166 wells located in the Sacramento Valley, northern California, were interpreted and compared to Cr concentrations to determine the origin and age of groundwater with elevated Cr(VI), and...
Authors
Andrew H. Manning, Christopher T. Mills, Jean M. Morrison, Lyndsay B. Ball
Hydrogeochemistry of prairie pothole region wetlands: Role of long-term critical zone processes Hydrogeochemistry of prairie pothole region wetlands: Role of long-term critical zone processes
This study addresses the geologic and hydrogeochemical processes operating at a range of scales within the prairie pothole region (PPR). The PPR is a 750,000 km2portion of north central North America that hosts millions of small wetlands known to be critical habitat for waterfowl and other wildlife. At a local scale, we characterized the geochemical evolution of the 92-ha Cottonwood Lake...
Authors
Martin B. Goldhaber, Christopher T. Mills, Jean M. Morrison, Craig A. Stricker, David M. Mushet, James W. LaBaugh
The relative contribution of methanotrophs to microbial communities and carbon cycling in soil overlying a coal-bed methane seep The relative contribution of methanotrophs to microbial communities and carbon cycling in soil overlying a coal-bed methane seep
Seepage of coal-bed methane (CBM) through soils is a potential source of atmospheric CH4 and also a likely source of ancient (i.e. 14C-dead) carbon to soil microbial communities. Natural abundance 13C and 14C compositions of bacterial membrane phospholipid fatty acids (PLFAs) and soil gas CO2 and CH4 were used to assess the incorporation of CBM-derived carbon into methanotrophs and other...
Authors
Christopher T. Mills, Gregory F. Slater, Robert F. Dias, Stephanie A. Carr, Christopher M. Reddy, Raleigh Schmidt, Kevin W. Mandernack
Laboratory investigations of the effects of nitrification-induced acidification on Cr cycling in vadose zone material partially derived from ultramafic rocks Laboratory investigations of the effects of nitrification-induced acidification on Cr cycling in vadose zone material partially derived from ultramafic rocks
Sacramento Valley (California, USA) soils and sediments have high concentrations of Cr(III) because they are partially derived from ultramafic material. Some Cr(III) is oxidized to more toxic and mobile Cr(VI) by soil Mn oxides. Valley soils typically have neutral to alkaline pH at which Cr(III) is highly immobile. Much of the valley is under cultivation and is both fertilized and...
Authors
Christopher T. Mills, Martin B. Goldhaber
Using stable isotopes to understand hydrochemical processes in and around a Prairie Pothole wetland in the Northern Great Plains, USA Using stable isotopes to understand hydrochemical processes in and around a Prairie Pothole wetland in the Northern Great Plains, USA
Millions of internally drained wetland systems in the Prairie Potholes region of the northern Great Plains (USA and Canada) provide indispensable habitat for waterfowl and a host of other ecosystem services. The hydrochemistry of these systems is complex and a crucial control on wetland function, flora and fauna. Wetland waters can have high concentrations of SO2-4 due to the oxidation...
Authors
Christopher T. Mills, Martin B. Goldhaber, Craig A. Stricker, JoAnn M. Holloway, Jean M. Morrison, Karl J. Ellefsen, Donald O. Rosenberry, Roland S. Thurston
The role of critical zone processes in the evolution of the Prairie Pothole Region wetlands The role of critical zone processes in the evolution of the Prairie Pothole Region wetlands
The Prairie Pothole Region, which occupies 900,000 km2 of the north central USA and south central Canada, is one of the most important ecosystems in North America. It is characterized by millions of small wetlands whose chemistry is highly variable over short distances. The study involved the geochemistry of surface sediments, wetland water, and groundwater in the Cottonwood Lakes area...
Authors
Martin B. Goldhaber, Christopher T. Mills, Craig A. Stricker, Jean M. Morrison