LATEST RESEARCH
The changing Arctic and organic matter matters! This is a multi-level, molecular-level C characterization project to decipher what C is there and what it's going to do. Does it stimulate processes that will irreversibly change our marine waters and coastal ecosystems? Stay tuned!
Led by: Juliana D'Andrilli (UNT), Shelby Buckley (UC Boulder & UNT), and Tessa Crouch (UCSD & UNT).
The river is receiving more allochthonous loads with climate warming. These loads are shifting the interaction between autotrophs and heterotrophs from mutualism to competition, leading to more carbon dioxide release to the atmosphere, describing a shift in the river's metabolic regime. The time is now to measure the character of the incoming loads and how that material is processed in the river before it flows out into the ocean. This project is a large collaboration across diverse disciplines including hydrology, biology, chemistry, and ecology.
Led by: Benoit Demars (NIVA), Leah Jackson-Blake (NIVA), Stein Rune Karlsen (Norwegian Research Centre), and Juliana D'Andrilli (UNT).
What DOM compounds fluoresce in natural and engineered ecosystems?
We are identifying the chemical compounds that can be detected with Excitation Emission Matrix Fluorescence Spectroscopy using direct measurement techniques in order to unify fluorescent community language that will minimize confusion and misinterpretations. Researchers, both young and old, let’s keep the conversation going and learn more from DOM photophysical properties that we can measure by EEMs.
Led by Fernando Rosario-Ortiz (University of Colorado, Boulder) and Juliana D'Andrilli (UNT)
Environmental Science & Technology 2022: PDF
Environmental Science & Technology 2020: PDF
How have human beings impacted these waters?
We are identifying spatiotemporal patterns of fluorescent DOM in the West Fork of the Gallatin River, coupling gross primary production, ecosystem respiration, and DOM characterization as the system moves from peak to base flow conditions with increasing land-use development.
Led by Robert A. Payn (Montana State University)
and Juliana D'Andrilli (UNT)
Size exclusion chromatography (SEC) in combination with optical measurements (e.g., absorbance and fluorescence) has become a popular form of analysis to characterize dissolved organic matter (DOM) as a function of molecular size. Here, SEC coupled with in-line absorbance scan and fluorescence emission scan was utilized to derive apparent fluorescence quantum yield (Φf) as a function of molecular weight (MW) for DOM. Individual instrument specific SEC-fluorescence detector correction factors were developed by comparison of a SEC based excitation emission matrix (EEM) to an excitation emission matix EEM generated by a calibrated benchtop fluorometer. The method was then applied to several sample sets to demonstrate how to measure the Φf on unknown DOM samples and to observe changes to Φf following a processing mechanism (ozonation). The Φf of riverine water samples and DOM fulvic acid isolates from Suwannee River and Pony Lake increased from <0.5% to a maximum of ~2.5-3% across the medium to low MW range. Following ozonation of PLFA, the Φf increased most notably in the large MW fractions (elution volumes < 40 mL). Overall, this method provides a means by which highly fluorescent size fractions of DOM can be identified for more detailed analyses of carbon quality and its changes through different processing mechanisms.
Team: Blair Hanson, Shelby Buckley, Sarah Fischer, and Fernando Rosario-Ortiz (University of Colorado Boulder), Urban Wünsch (Technical University of Denmark and Chalmers University of Technology), Kathleen Murphy (Chalmers University of Technology), and Juliana D’Andrilli (UNT)
ACS Environmental Science & Technology: Water: PDF
This is a mass spectrometry (MS) DOM research project with multiple participating laboratories worldwide working towards an understanding of the marine and terrestrial DOM signatures in marine water masses of the Arctic Ocean. The project centers on using high resolution Fourier transform ion cyclotron resonance mass spectrometry for detailed chemical characterization at the molecular level.
Led by: Colin A. Stedmon (DTU), Mats Granskog (Norwegian Polar Institute), Christopher Osburn (North Carolina State University), and Juliana D'Andrilli (UNT).
What effects does legacy mining have on river ecosystems and how will the EPA's superfunded Upper Clark Fork River project change ecosystem regimes over the next 20 years?
We are a large team of 5 researchers seeking to identify the metabolic ecosystem regime changes with ongoing river restoration efforts. The team's multidisciplinary efforts are focused on metal concentrations, water quality (inorganic and organic carbon), DOM quality and metal complexation, hydrology, and biological dynamics from microbes to aquatic organisms, such as insects and fish.
Led by: Maury Valett (University of Montana), Mike DeGrandpre (University of Montana), Juliana D'Andrilli (UNT), Rob Payn (Montana State University), and Marc Peipoch (Stroud Water Research Center).
Limnology & Oceanography Bulletin: PDF
How can we use OM fluorescent signatures to reconstruct past and present atmospheric compositions?
What OM type is preserved in the ice now and what will it do upon release from polar ice sheets in a warming climate?
OM composition from Greenland and Canada were characterized by Excitation Emission Matrices and compared to the first deep ice core OM record (WD, Antarctica). Arctic and Antarctic ice sheets were characterized as reservoirs of reactive carbon and upon release, albeit through one or more bio-, chemico-, and photo-reactive mechanisms, may stimulate positive carbon cycling feedbacks of greenhouse gases exacerbating climate warming.
Project team: Juliana D'Andrilli (UNT) and Joseph R. McConnell (Desert Research Institute, Reno, NV)
Journal of Glaciology: PDF
​
What types of OM compounds and microbial matter fluoresce beneath the gypsum surface?
Gypsum is associated with sedimentary rocks and is deposited in both lake and ocean water. It exists on Mars at every location visited and is expected at Jezero (crater on Mars). We are running elemental analysis of these materials to confirm the presence of organic carbon. The WATSON will be used to demonstrate that in situ Deep UV scanning with a down-borehole instrument can detect potential organic biosignatures preserved in an evaporite deposit on Earth. This technique may be applicable to future Mars deep drilling missions to look for life in the deep subsurface.
Team: Michael J. Malaska, Luther Beegle, and Kenneth S. Manatt, William J. Abbey (Jet Propulsion Laboratory and California Insititue of Technology), Rohit Bhartia (Photon Systems, Inc.), John C. Priscu and Madeline Willis (Montana State University), Boleslaw Mellerowicz, Joseph Palmowski, Gale L. Paulsen, Kris Zacny (Honeybee Robotics), Evan J. Eshelman (Impossible Sensing), Gregory Wanger (Down North Technologies), and Juliana D’Andrilli (UNT)
​