Current Projects in the Lab:
Rhizosphere Carbon Fluxes during Hydraulic Redistribution
The overall aim of the proposed research is to understand how hydraulic redistribution changes root the spatial extent and intensity of rhizosphere carbon fluxes from roots. HR is the nighttime flux of water from wet soil to dry soil via plant roots. This flux of water may also transport biomolecules from roots into the rhizosphere, and these fluxes of water and exuded biomolecules may trigger hot moments of rhizosphere microbial activity, sustaining soil biogeochemical cycling during drought. The specific objectives of the project are to quantify how HR alters the magnitude, composition, and location of root exudation in the rhizosphere. In this project, we are using a combination of greenhouse and modelling approaches to quantify fluxes, incorporating experimental data into the TREES ecophysiology model. This project is led by lab member Fiona Ellsworth and is in collaboration with Scott Mackay (UB) and Angela Possinger (Virginia Tech). This work is funded by the US Department of Energy under grant #SC-0023019.
The overall aim of the proposed research is to understand how hydraulic redistribution changes root the spatial extent and intensity of rhizosphere carbon fluxes from roots. HR is the nighttime flux of water from wet soil to dry soil via plant roots. This flux of water may also transport biomolecules from roots into the rhizosphere, and these fluxes of water and exuded biomolecules may trigger hot moments of rhizosphere microbial activity, sustaining soil biogeochemical cycling during drought. The specific objectives of the project are to quantify how HR alters the magnitude, composition, and location of root exudation in the rhizosphere. In this project, we are using a combination of greenhouse and modelling approaches to quantify fluxes, incorporating experimental data into the TREES ecophysiology model. This project is led by lab member Fiona Ellsworth and is in collaboration with Scott Mackay (UB) and Angela Possinger (Virginia Tech). This work is funded by the US Department of Energy under grant #SC-0023019.
Molecular Imaging of Root and Soil Carbon during Drought
Drought causes profound stress on the fine root network of plants, and root physiological responses to drought can determine how resilient soil biogoechemical cycles are to drought. In this work, we are looking at how the spatial distribution and composition of rhizosphere biomolecules changes as a result of drought stress. Using Populus trichocarpa as a focal species, we are collecting molecular "imprints" of root and rhizosphere biomolecules under progressive drought stress. We analyze these samples using advanced mass spectrometry imaging platforms at Pacific Northwest National Lab, including matrix-assisted laser desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI FT-ICR-MS) and Nano-desorption electrospray ionization Orbitrap mass spectrometry (NanoDESI Orbitrap MS). This work, led by lab member Fiona Ellsworth, is in collaboration with Dušan Veličković and Greg Vandergrift at PNNL. The work is supported by grant #60705 from the Environmental Molecular Sciences Laboratory, PNNL to PI Marinos and a Department of Energy Office of Science Graduate Student Research fellowship, awarded to lab member Fiona Ellsworth.
Drought causes profound stress on the fine root network of plants, and root physiological responses to drought can determine how resilient soil biogoechemical cycles are to drought. In this work, we are looking at how the spatial distribution and composition of rhizosphere biomolecules changes as a result of drought stress. Using Populus trichocarpa as a focal species, we are collecting molecular "imprints" of root and rhizosphere biomolecules under progressive drought stress. We analyze these samples using advanced mass spectrometry imaging platforms at Pacific Northwest National Lab, including matrix-assisted laser desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI FT-ICR-MS) and Nano-desorption electrospray ionization Orbitrap mass spectrometry (NanoDESI Orbitrap MS). This work, led by lab member Fiona Ellsworth, is in collaboration with Dušan Veličković and Greg Vandergrift at PNNL. The work is supported by grant #60705 from the Environmental Molecular Sciences Laboratory, PNNL to PI Marinos and a Department of Energy Office of Science Graduate Student Research fellowship, awarded to lab member Fiona Ellsworth.
Carbon and Nitrogen Dynamics of Coarse Woody Debris Decomposition : The Role of Roots
Coarse woody debris (e.g. large, dead branches, roots and trunks) is slow to decompose in forests in part because of the low nitrogen content of these tissues, which limits microbial growth. During the late stages of coarse woody debris decomposition, fine roots often proliferate throughout the debris, but the roles that these roots play in decomposing debris is not well understood. Here, we are performing a field experiment to test the hypothesis that these roots accelerate decomposition by providing a nitrogen subsidy to microbes. This work is led by undergrad lab member Kris Ogilvie and it is supported by a grant awarded to her from the UB Experiential Learning Network.
Coarse woody debris (e.g. large, dead branches, roots and trunks) is slow to decompose in forests in part because of the low nitrogen content of these tissues, which limits microbial growth. During the late stages of coarse woody debris decomposition, fine roots often proliferate throughout the debris, but the roles that these roots play in decomposing debris is not well understood. Here, we are performing a field experiment to test the hypothesis that these roots accelerate decomposition by providing a nitrogen subsidy to microbes. This work is led by undergrad lab member Kris Ogilvie and it is supported by a grant awarded to her from the UB Experiential Learning Network.
A Metabolomic Perspective on Root Exudate Phenology
Root exudates can account for up to 10% of total photosynthate fixed by plants, but these fluxes of carbon are notoriously difficult to study, especially for long-lived plant species that cannot be grown in the greenhouse. As a result, little is known about the seasonality and composition of root exudates for mature trees. In this project, we examine how the quantity and quality of root exudates change throughout the growing season, monthly collecting exudates from roots of mature tree species located in Letchworth Woods, UB North Campus. Using two focal species, red oak and American beech, we are examining the hypothesis that exudate fluxes spike in the spring and fall shoulder seasons and that exudates become more nitrogen-rich during these seasons. We are performing metabolomic profiling on these exudates using a metabolomic library developed in-house for use with UB's Q-Exactive Orbitrap liquid chromatography - mass spectrometry system. This work is led by M.S. student Jessica Paskie.
Root exudates can account for up to 10% of total photosynthate fixed by plants, but these fluxes of carbon are notoriously difficult to study, especially for long-lived plant species that cannot be grown in the greenhouse. As a result, little is known about the seasonality and composition of root exudates for mature trees. In this project, we examine how the quantity and quality of root exudates change throughout the growing season, monthly collecting exudates from roots of mature tree species located in Letchworth Woods, UB North Campus. Using two focal species, red oak and American beech, we are examining the hypothesis that exudate fluxes spike in the spring and fall shoulder seasons and that exudates become more nitrogen-rich during these seasons. We are performing metabolomic profiling on these exudates using a metabolomic library developed in-house for use with UB's Q-Exactive Orbitrap liquid chromatography - mass spectrometry system. This work is led by M.S. student Jessica Paskie.
Soil Carbon Interactions with Minerals under Fluctuating Redox Conditions
Soil carbon is the largest pool of organic carbon on the surface of the Earth, and preserving this carbon in soils is critical to keeping our climate liveable in the long term. Chemical reactions between soil minerals and soil carbon are one of the primary ways that soil carbon is stabilized in the soil and protected from microbial decomposition. Our lab looks at how fluctuating soil moisture conditions, which drive changes in soil oxygen availability and redox status, alter the stability of these soil carbon-mineral associations and the rates of microbial decomposition of carbon. Another axis of this work explores how the molecular characteristics of soil carbon changes the pathways by which soil carbon is stabilized by mineral surfaces and the degree to which microbes are involved in this stabilization. Our approach is primarily experimental, involving lab and greenhouse work. This work is led by Ph.D. student Fiona Ellsworth.
Soil carbon is the largest pool of organic carbon on the surface of the Earth, and preserving this carbon in soils is critical to keeping our climate liveable in the long term. Chemical reactions between soil minerals and soil carbon are one of the primary ways that soil carbon is stabilized in the soil and protected from microbial decomposition. Our lab looks at how fluctuating soil moisture conditions, which drive changes in soil oxygen availability and redox status, alter the stability of these soil carbon-mineral associations and the rates of microbial decomposition of carbon. Another axis of this work explores how the molecular characteristics of soil carbon changes the pathways by which soil carbon is stabilized by mineral surfaces and the degree to which microbes are involved in this stabilization. Our approach is primarily experimental, involving lab and greenhouse work. This work is led by Ph.D. student Fiona Ellsworth.
Past Projects:
Biogeochemistry of Urban Blight and Rejuvenation
Many Rust Belt cities such as Buffalo experienced depopulation in the second half of the 20th Century, leaving many properties abandoned and causing serious social, political and ecological problems. To address these problems, many cities have turned to the demolition of these properties and subsequent creative reuse of the land (e.g. urban farming). These reuses have a variety of ecological co-benefits such as stormwater management. Our lab works on understanding how vacant lot demolition and regreening impacts the hydrology and biogeochemistry of urban Buffalo. We are contrasting different land reuse intensities, from mown grass to urban farming, to see how these practices alter carbon and nitrogen cycling in the subsurface. We are particularly interested in denitrification and other redox-sensitive processes, and we are using an observational, field-based approach to tackle these questions. This work is led by M.S. student Philip Conrad and is funded by the NYS Water Resources Institute.
Conrad, P. E., Marinos, R. E. (2024) Nitrogen Availability and Denitrification in Urban Agriculture and Regreened Vacant Lots. Urban Ecosystems. doi:10.1007/s11252-024-01532-2
Many Rust Belt cities such as Buffalo experienced depopulation in the second half of the 20th Century, leaving many properties abandoned and causing serious social, political and ecological problems. To address these problems, many cities have turned to the demolition of these properties and subsequent creative reuse of the land (e.g. urban farming). These reuses have a variety of ecological co-benefits such as stormwater management. Our lab works on understanding how vacant lot demolition and regreening impacts the hydrology and biogeochemistry of urban Buffalo. We are contrasting different land reuse intensities, from mown grass to urban farming, to see how these practices alter carbon and nitrogen cycling in the subsurface. We are particularly interested in denitrification and other redox-sensitive processes, and we are using an observational, field-based approach to tackle these questions. This work is led by M.S. student Philip Conrad and is funded by the NYS Water Resources Institute.
Conrad, P. E., Marinos, R. E. (2024) Nitrogen Availability and Denitrification in Urban Agriculture and Regreened Vacant Lots. Urban Ecosystems. doi:10.1007/s11252-024-01532-2
Watershed Solute Export during Rain-on-Snow Events
Rain-on-snow events can trigger massive export of solutes from watersheds, owing to the rapid mobilization of snowmelt and conveyance of groundwater to receiving streams. In this project, we are working to document the prevalence of rain-on-snow events across the continental US, determine if the prevalence is changing due to climate change, and qunantify how much these events contribute to total annual solute fluxes from small watersheds. In this work, we are synthesizing large-scale spatial datasets of snow cover, precipitation intensity, hydrolgic discharge, and water chemistry. We are interested in solutes of both biogenic (e.g. dissolved organic carbon, nitrate) and geogenic origin (e.g. silica, calcium), and we hope to further leverage this data to infer how rain-on-snow events differ from other precipitation events with regard to subsurface flow dynamics. This work is in collaboration with Erin Seybold (Kansas Geological Survey) and John Gardner (Pitt).
Marinos, R. E. (2021). SNODASR: Tools for manipulating SNODAS data in R (Version 1.0). doi:10.5281/zenodo.4568272
Rain-on-snow events can trigger massive export of solutes from watersheds, owing to the rapid mobilization of snowmelt and conveyance of groundwater to receiving streams. In this project, we are working to document the prevalence of rain-on-snow events across the continental US, determine if the prevalence is changing due to climate change, and qunantify how much these events contribute to total annual solute fluxes from small watersheds. In this work, we are synthesizing large-scale spatial datasets of snow cover, precipitation intensity, hydrolgic discharge, and water chemistry. We are interested in solutes of both biogenic (e.g. dissolved organic carbon, nitrate) and geogenic origin (e.g. silica, calcium), and we hope to further leverage this data to infer how rain-on-snow events differ from other precipitation events with regard to subsurface flow dynamics. This work is in collaboration with Erin Seybold (Kansas Geological Survey) and John Gardner (Pitt).
Marinos, R. E. (2021). SNODASR: Tools for manipulating SNODAS data in R (Version 1.0). doi:10.5281/zenodo.4568272
River Network Structure and Agricultural Nitrogen Export
Nitrogen pollution in the Mississippi is one of the most vexing long-term water quality issues. Often, the relationship between river flow (discharge) and the concentration of solutes (such as nitrogen) are used to infer the processes driving the mobilization of these solutes into waterways. These efforts can be confounded by the fact that river network structure can profoundly alter concentration-discharge dynamics, though, especially at larger spatial scales. In this work, we examined the Upper Mississippi River basin (492,000 sq. km.) to elucidate how land use and river network structure jointly control nitrate concentration-discharge relationships. This work was a data synthesis effort, in which we reanalyzed publicly-available water quality, hydrography and land use datasets.
Marinos, R. E., Van Meter, K. J., Basu, N. B. (2021) Is the River a Chemostat?: Scale Versus Land Use Controls on Nitrate Concentration-Discharge Dynamics in the Upper Mississippi River Basin. Geophysical Research Letters. doi:10.1029/2020GL087051
Nitrogen pollution in the Mississippi is one of the most vexing long-term water quality issues. Often, the relationship between river flow (discharge) and the concentration of solutes (such as nitrogen) are used to infer the processes driving the mobilization of these solutes into waterways. These efforts can be confounded by the fact that river network structure can profoundly alter concentration-discharge dynamics, though, especially at larger spatial scales. In this work, we examined the Upper Mississippi River basin (492,000 sq. km.) to elucidate how land use and river network structure jointly control nitrate concentration-discharge relationships. This work was a data synthesis effort, in which we reanalyzed publicly-available water quality, hydrography and land use datasets.
Marinos, R. E., Van Meter, K. J., Basu, N. B. (2021) Is the River a Chemostat?: Scale Versus Land Use Controls on Nitrate Concentration-Discharge Dynamics in the Upper Mississippi River Basin. Geophysical Research Letters. doi:10.1029/2020GL087051
Ecosystem Recovery from Acid Rain: Carbon and Nitrogen Cycling in the Soil-Stream Continuum
While acid rain is a wonderful example of an environmental problem that has been solved through collective action, forests across the developed world are still dealing with the legacies of over a century of intense acid deposition. Many of these forests are just beginning to recover from acid deposition, fifty years after acid rain peaked, and the future extent and trajectory of this recovery remains unclear. In my dissertation work, I examined how watershed carbon and nitrogen cycling accelerated as a forest recovered from acid rain. I did this work in the context of an acid rain recovery experiment at Hubbard Brook Experimental Forest (NH), where an 11 ha acid-impacted watershed was treated with calcium silicate to ameliorate the impacts of acid rain.
Marinos, R. E. and Bernhardt, E. S. (2018) Soil carbon losses due to higher pH offset vegetation gains due to calcium enrichment in an acid mitigation experiment. Ecology, 99: 2363-2373. doi:10.1002/ecy.2478
Marinos, R. E., Campbell, J. C., Driscoll, C. T., Likens, G. E., McDowell, W. H., Rosi, E. J., Rustad, L. E., and Bernhardt, E. S. (2018) Give and Take: Watershed acid remediation increases stormflow nitrogen export but increases baseflow in-stream nitrogen retention. Environmental Science and Technology, 52 (22): 13155–13165. doi: 10.1021/acs.est.8b03553
Marinos, R.E., Driscoll, C. T., Groffman, P. M., and Bernhardt, E. S. (2024) Accelerated nitrogen cycling during ecosystem recovery from acid precipitation. Soil Biology and Biochemistry. doi:10.1016/j.soilbio.2023.109286