Current projects
A fossil ecosystem under the ice: deciphering the glacial and vegetation history of northwest Greenland using long-lost Camp Century basal sediment
This multi-disciplinary, international project studies the material from 22 samples of Camp Century sub-glacial sediment.
Using a depth profile (3.44 m), we aim to decipher the paleoclimate, glacial, and ecological history of northwestern Greenland over the Pleistocene. We will constrain the timing and processes of sediment erosion and deposition as ice came and went by applying a
coordinated array of geochemical, isotopic, geochronologic and palaeoecology techniques.
PI: Paul Bierman, Co-PIs: Drew Christ, Nico Perdrial
Funded by NSF Arctic Natural Sciences
This multi-disciplinary, international project studies the material from 22 samples of Camp Century sub-glacial sediment.
Using a depth profile (3.44 m), we aim to decipher the paleoclimate, glacial, and ecological history of northwestern Greenland over the Pleistocene. We will constrain the timing and processes of sediment erosion and deposition as ice came and went by applying a
coordinated array of geochemical, isotopic, geochronologic and palaeoecology techniques.
PI: Paul Bierman, Co-PIs: Drew Christ, Nico Perdrial
Funded by NSF Arctic Natural Sciences
Assessing Nutrient Sustainability In Forest Management: Novel Applications Of Metal Isotopes And In-Situ Mineral Measurements
Because the effects of harvesting severity and repeated harvests on long-term nutrient sustainability is uncertain, but net losses of base cation nutrients (e.g. calcium, magnesium, and potassium) can result in decreased woody biomass, potentially greater than the 20% seen in Scandinavian forests, we quantify nutrients in soils and minerals and their effects on aboveground biomass across management types and harvesting severities. We conduct field studies on nutrient cycling and acquisition experiments at four experimental forests with different nutrient availabilities in northeastern United States. We determine nutrients utilized by regrowth from recycled materials through novel mineral dissolution experiments and new applications of stable isotopes (δ44Ca, δ26Mg, and δ41K) to soils and vascular solutions.
PI: Justin Richardson, Co-PIs: Nico Perdrial, Tony D'Amato; MS: Victoria Treto
Funded by USDA, National Institute of Food and Agriculture
Because the effects of harvesting severity and repeated harvests on long-term nutrient sustainability is uncertain, but net losses of base cation nutrients (e.g. calcium, magnesium, and potassium) can result in decreased woody biomass, potentially greater than the 20% seen in Scandinavian forests, we quantify nutrients in soils and minerals and their effects on aboveground biomass across management types and harvesting severities. We conduct field studies on nutrient cycling and acquisition experiments at four experimental forests with different nutrient availabilities in northeastern United States. We determine nutrients utilized by regrowth from recycled materials through novel mineral dissolution experiments and new applications of stable isotopes (δ44Ca, δ26Mg, and δ41K) to soils and vascular solutions.
PI: Justin Richardson, Co-PIs: Nico Perdrial, Tony D'Amato; MS: Victoria Treto
Funded by USDA, National Institute of Food and Agriculture
Development and Application of PXRF Protocols to Potentially Hazardous Metals in Soils of Urban
Forests and Gardens
This research addresses 3 challenges:
1. How do soil moisture, organic matter, and rock fragments affect in-situ and ex-situ pXRF measurements?
2. Do trace metal distributions and concentrations (particularly As, Cd, Pb, Cu, Zn, Mn) in urban soils depend on lithology, land-use history, or traditional parameters (pH, clay content, and organic matter content)?
3. Can toxic metal concentrations in urban soils measured by pXRF be used to predict increased uptake of toxic metals in crops of urban gardens or native and invasive woody plants in urban forests?
PI: Justin Richardson, Co-PIs: Nico Perdrial, MS: Sandra Walser
Funded by USDA, Natural Resources Conservation Service
Forests and Gardens
This research addresses 3 challenges:
1. How do soil moisture, organic matter, and rock fragments affect in-situ and ex-situ pXRF measurements?
2. Do trace metal distributions and concentrations (particularly As, Cd, Pb, Cu, Zn, Mn) in urban soils depend on lithology, land-use history, or traditional parameters (pH, clay content, and organic matter content)?
3. Can toxic metal concentrations in urban soils measured by pXRF be used to predict increased uptake of toxic metals in crops of urban gardens or native and invasive woody plants in urban forests?
PI: Justin Richardson, Co-PIs: Nico Perdrial, MS: Sandra Walser
Funded by USDA, Natural Resources Conservation Service
Lead Water and Soil Education and Assessment by Vermont Middle and High School Students.
This research and education project uses community science to identify Pb contamination in soils and tap water in the culturally and economically diverse urban and suburban communities of Burlington and Winooski, Vermont by teaming University experts with Middle and High school students and teachers. We use these data and the student education process to inform communities at risk about Pb contamination and Pb-safe practices. We Design a step-by-step, transferrable, standardized practice guide for the identification and amelioration of Pb contamination using coordination between urban school systems, institutions of higher education, and community partners.
PI: Nico Perdrial, Co-PI: Paul Bierman, Collaborators: Sandy Walser (MS), Christine Massey (Outreach Coordinator), Eva Pepe, Rebecca Holt and Ru Oppenheimer Funded by the EPA Healthy Communities Program.
This research and education project uses community science to identify Pb contamination in soils and tap water in the culturally and economically diverse urban and suburban communities of Burlington and Winooski, Vermont by teaming University experts with Middle and High school students and teachers. We use these data and the student education process to inform communities at risk about Pb contamination and Pb-safe practices. We Design a step-by-step, transferrable, standardized practice guide for the identification and amelioration of Pb contamination using coordination between urban school systems, institutions of higher education, and community partners.
PI: Nico Perdrial, Co-PI: Paul Bierman, Collaborators: Sandy Walser (MS), Christine Massey (Outreach Coordinator), Eva Pepe, Rebecca Holt and Ru Oppenheimer Funded by the EPA Healthy Communities Program.
Nanoscale phosphate weathering
What: How exactly does weathering of phosphates work? We investigate the very beginning of weathering at the nano scale by testing the “interfacial dissolution-reprecipitation weathering model”.
Why: Phosphate minerals are the main source of phosphorus in rock fertilizers and weathering determines the availability of a life-sustaining nutrient, nevertheless, phosphate weathering dynamics are not well understood. Traditionally, chemical alteration of crystalline and amorphous materials in aqueous solutions was thought to be controlled by preferential cation release and interdiffusion with protons, the material-environment interface consisting of a ‘cation leached layer’. Advances in nanoscale analytical techniques are shifting this view to the concept of coupled interfacial dissolution-reprecipitation (CIDR) which proposes that silicate weathering is controlled by a nanoscale dissolution-reprecipitation process. This fundamentally changes our understanding of how weathering proceeds and what limiting factors are. Whereas the consensus is shifting toward CIDR for silicates, little work has been conducted on non-silicates. Although phosphate minerals belong to one of the most important mineral groups at the earth’s surface, the nanoscale processes that control their weathering behavior remain largely unknown.
How: To determine if the CIDR weathering model for silicate minerals can be applied to explain phosphate mineral weathering, we combine state-of-the-art analytical techniques (XRD, STEM-HAADF, EFTEM, APT, ToF and nanoSIMS) with benchtop and field experiments.
Who: MS student Adele Conde, BS Christian Wurzburger; Collaborators: Roland Hellmann (Grenoble, France), David Singer (Kent State), Liz Rampe (NASA JSC), Marc Michel (Virginia Tech)
What: How exactly does weathering of phosphates work? We investigate the very beginning of weathering at the nano scale by testing the “interfacial dissolution-reprecipitation weathering model”.
Why: Phosphate minerals are the main source of phosphorus in rock fertilizers and weathering determines the availability of a life-sustaining nutrient, nevertheless, phosphate weathering dynamics are not well understood. Traditionally, chemical alteration of crystalline and amorphous materials in aqueous solutions was thought to be controlled by preferential cation release and interdiffusion with protons, the material-environment interface consisting of a ‘cation leached layer’. Advances in nanoscale analytical techniques are shifting this view to the concept of coupled interfacial dissolution-reprecipitation (CIDR) which proposes that silicate weathering is controlled by a nanoscale dissolution-reprecipitation process. This fundamentally changes our understanding of how weathering proceeds and what limiting factors are. Whereas the consensus is shifting toward CIDR for silicates, little work has been conducted on non-silicates. Although phosphate minerals belong to one of the most important mineral groups at the earth’s surface, the nanoscale processes that control their weathering behavior remain largely unknown.
How: To determine if the CIDR weathering model for silicate minerals can be applied to explain phosphate mineral weathering, we combine state-of-the-art analytical techniques (XRD, STEM-HAADF, EFTEM, APT, ToF and nanoSIMS) with benchtop and field experiments.
Who: MS student Adele Conde, BS Christian Wurzburger; Collaborators: Roland Hellmann (Grenoble, France), David Singer (Kent State), Liz Rampe (NASA JSC), Marc Michel (Virginia Tech)
Stream response to extreme events in tropical environments - The Luquillo CZO, PR
Collaborative project PI: Bill McDowell (UNH), collaborators: Kathryn Clark & Alain Plante (UPenn), Jamie Shanley (USGS), Julia Perdrial (UVM) Trevor Mackoviak (UVM).
This multidisciplinary research project focuses on the effects of storm events on stream response after prolonged drought. It is located in the Luquillo CZO (Puerto Rico). My responsibility is to analyzes and interpret the response of suspended sediment loads in 2 rivers impacted by a series of storms after a drought.
Collaborative project PI: Bill McDowell (UNH), collaborators: Kathryn Clark & Alain Plante (UPenn), Jamie Shanley (USGS), Julia Perdrial (UVM) Trevor Mackoviak (UVM).
This multidisciplinary research project focuses on the effects of storm events on stream response after prolonged drought. It is located in the Luquillo CZO (Puerto Rico). My responsibility is to analyzes and interpret the response of suspended sediment loads in 2 rivers impacted by a series of storms after a drought.
Past projects
Past, Present and Future weathering on Mars What: We use ideas from terrestrial Critical Zone science to design effective analogue experiments to investigate weathering on Mars. The terrestrial Critical Zone is the near surface environment that includes atmosphere, vegetation, soils and rock and is investigated in an increasingly interdisciplinary setting. From CZ research we know that atmospheric composition and “shocks” to the system dramatically impact the functioning of this zone.
Why: Planetary science is one of the new frontiers and improved space travel technologies might make human visits to Mars possible in our lifetime. However, what effect will human presence have on Mars and can we learn from our experience on Earth to understand and model our potential impact on Mars? The type of impact that human will have is difficult to predict and data from meaningful analogue experiments are necessary to inform predictive models.
How: We investigate planetary drivers for weathering on Mars and design analogue experiments that capture conditions on Mars more realistically than previous approaches. Specifically we test the effect of atmospheric composition and freeze-thaw cycles (“shocks” to the system) by performing column experiments where a pH2 (HCl-H2SO4-H2O) solution is infiltrated into columns packed with Martian regolith analogue (JSC-MARS1) under CO2 atmosphere and frequent freeze-thaw cycles (Fig. 5). Freeze thaw cycles produced greater weathering rates, and we hypothesize that water scarcity, associated with freezing events, contribute to localized weathering hotspots where solutions become concentrated at discrete mineral interface.
Who: MS student Grant Reeder, J. Armfield, BS Alex Gagnon; Collaborators: Julia Perdrial (UVM), Liz Rampe (NASA JSC)
Why: Planetary science is one of the new frontiers and improved space travel technologies might make human visits to Mars possible in our lifetime. However, what effect will human presence have on Mars and can we learn from our experience on Earth to understand and model our potential impact on Mars? The type of impact that human will have is difficult to predict and data from meaningful analogue experiments are necessary to inform predictive models.
How: We investigate planetary drivers for weathering on Mars and design analogue experiments that capture conditions on Mars more realistically than previous approaches. Specifically we test the effect of atmospheric composition and freeze-thaw cycles (“shocks” to the system) by performing column experiments where a pH2 (HCl-H2SO4-H2O) solution is infiltrated into columns packed with Martian regolith analogue (JSC-MARS1) under CO2 atmosphere and frequent freeze-thaw cycles (Fig. 5). Freeze thaw cycles produced greater weathering rates, and we hypothesize that water scarcity, associated with freezing events, contribute to localized weathering hotspots where solutions become concentrated at discrete mineral interface.
Who: MS student Grant Reeder, J. Armfield, BS Alex Gagnon; Collaborators: Julia Perdrial (UVM), Liz Rampe (NASA JSC)
Effects of iron oxide concentrations on Pb bioavailability in PO4 amended soils.
What: Lead ranges among the top most toxic substances in near surface environments and remediation of lead impacted soils is largely unsuccessful. With this project we are testing specific hypotheses around processes that could influence success of remediation. Specifically we hypothesize that ionic interactions in soil microenvironments lead to incomplete transformation of Pb into pyromorphite, which keeps a large fraction of lead bioacessible.
Why: Especially in urban settings, lead toxicity disproportionally affects low income communities because funds for lead abatement are often not available. For example, soils in Burlington, Vermont are heavily impacted by Pb contamination, principally due to the historic use of Pb-based paint (Bower et al., 2017). Soil sampled at residences, analyzed for total and bioavailable Pb to determine their toxicity relative to the EPA standards, showed that 39% of residential soils exceeded the EPA guidance limit for non-play areas (1,200 mg/kg) and that approximately 50% of Burlington soil Pb is bioavailable.
How: In order to simulate microenvironments we inoculate a Pb contaminated soil with nanogoethite and leach these soils with PO4-amended synthetic rainwater in column experiments. A suite of analysis is then carried out on the solids to assess how competitive sorption affect lead mobility. In order to account for the heterogeneity of the soil and identify crystalline species of Pb at the microscale/mesoscale, bulk X-ray diffraction (XRD) patterns are acquired, and in order to determine changes in type and amount of mineral phases Rietveld refinements are required.
Who: MS student Grant Reeder, BS Lily Zanta, Amanda Rossi; Collaborators: David Singer (Kent State), Aaron Thompson (U of Georgia)
Uranium and strontium fate in waste-weathered sediments: Scaling of molecular processes to predict reactive transport
Collaborative project (DOE, SBR funded, 2011-2014), PI: Jon Chorover (UofA), co-PI: Peggy O'Day (UC Merced), Karl Mueller, John Zachara & Wooyong Um (PNNL), Carl Steefel (LBNL) .
Project objectives:
1. Determine the process coupling that occurs between mineral transformation and contaminant (U and
Sr) speciation in acid-uranium waste weathered Hanford sediments.
2. Establish linkages between molecular-scale contaminant speciation and meso-scale contaminant lability, release and reactive transport.
3. Make conjunctive use of molecular- to field-scale data to constrain the development of a mechanistic, reactive transport model that includes coupling of contaminant sorption-desorption and mineral transformation reactions.
Main results:
Acid weathering contributes to uranium silicate precipitation.
PO4 amendments exert a strong control over U speciation.
Uranium is effectively stabilized by additions of phosphates.
Collaborative project (DOE, SBR funded, 2011-2014), PI: Jon Chorover (UofA), co-PI: Peggy O'Day (UC Merced), Karl Mueller, John Zachara & Wooyong Um (PNNL), Carl Steefel (LBNL) .
Project objectives:
1. Determine the process coupling that occurs between mineral transformation and contaminant (U and
Sr) speciation in acid-uranium waste weathered Hanford sediments.
2. Establish linkages between molecular-scale contaminant speciation and meso-scale contaminant lability, release and reactive transport.
3. Make conjunctive use of molecular- to field-scale data to constrain the development of a mechanistic, reactive transport model that includes coupling of contaminant sorption-desorption and mineral transformation reactions.
Main results:
Acid weathering contributes to uranium silicate precipitation.
PO4 amendments exert a strong control over U speciation.
Uranium is effectively stabilized by additions of phosphates.
Nature and role of the solid suspended matter in the dynamic of pollutant transfer
French Ministry of Research Fellowship, PI: Francoise Elsass (INRA Versailles, Fr) and Nicole Liewig (CNRS, Strasbourg, Fr).
Development of a new technique for in-situ sampling of nanoparticles. In-situ monitoring of soil and atmospheric colloids reactivity (organic & inorganic) applying HRTEM-EDX, SEM-EDX and Laser Granulometry. More than 500 hours of TEM experience. Determination of the factors influencing colloids and nanoparticles in the environment. Chemical speciation, TEM, Cryo-SEM and ESEM investigation on bacteria-As interaction.
Main results:
French Ministry of Research Fellowship, PI: Francoise Elsass (INRA Versailles, Fr) and Nicole Liewig (CNRS, Strasbourg, Fr).
Development of a new technique for in-situ sampling of nanoparticles. In-situ monitoring of soil and atmospheric colloids reactivity (organic & inorganic) applying HRTEM-EDX, SEM-EDX and Laser Granulometry. More than 500 hours of TEM experience. Determination of the factors influencing colloids and nanoparticles in the environment. Chemical speciation, TEM, Cryo-SEM and ESEM investigation on bacteria-As interaction.
Main results:
- Hydrodynamic properties are controlling the distribution of nanoparticles with depth and time in soil.
- Rain conditions and vegetation cover are controlling the distribution kinetics in atmospheric fallout.
- Bacteria are important vector of heavy metals.
- Aggregation processes take place in the flowing porosity.
Behavior of chemical elements during weathering: Mobility and concentration factors, application to archaeological ceramics.
MS research thesis, PI: Bruce Velde (CNRS, ENS Paris)
Development of a new geochemical concept for tracing the provenance of ceramics using the behavior of chemical element during weathering by applying Electron Microprobe and Laser Ablation ICP-MS analysis.
Main results:
MS research thesis, PI: Bruce Velde (CNRS, ENS Paris)
Development of a new geochemical concept for tracing the provenance of ceramics using the behavior of chemical element during weathering by applying Electron Microprobe and Laser Ablation ICP-MS analysis.
Main results:
- Interdisciplinary study (geosciences & archaeology) improves the provenance of ceramics.
- Technology of ancient time can be determined by mineralogical study.
- According to the source of parent material, ceramics have a clear isotopic signature.
last update: August 2022