Water connects systems...
our hillslopes to our oceans,
our terrestrial to our aquatic ecosystems,
and our industries to our environment...
our hillslopes to our oceans,
our terrestrial to our aquatic ecosystems,
and our industries to our environment...
RESEARCH TOPICS
Our research investigates the biophysical processes of water in the Earth's Critical Zone. We utilize our strengths in hydrology and biogeochemistry to gain a more complete understanding of ecosystem structure, function, and services. We specialize in the interfaces between ground and surface waters and river corridor sciences. Our research is an integral part of the emerging field of Hydroecology, which seeks to understand the influence of hydrology on ecosystems and biogeochemical cycles. The main themes of our research are:
- Groundwater-surface water interactions (Riparian and Hyporheic Zones)
- Arctic and permafrost influenced catchment hydrology and stream ecosystems
- Nitrogen and Carbon export and retention in catchments
- Emergent patterns in environmental biogeochemistry of aquatic ecosystems
- Quantifying and prediction aquatic ecosystem structure, function, and water quality
Main Projects
Fate of Permafrost Nutrients: Arctic Stream Networks as Sensors of Permafrost Ecosystems
Permafrost is ground that remains frozen for at least two consecutive years. It spans approximately one fourth of the northern hemisphere's land surface and contains large stores of carbon and nutrients such as nitrogen and phosphorus. As Arctic Alaska warms and permafrost thaws, these nutrients are released, which supports plant growth but also can accelerate the production of greenhouse gases, affecting local habitat and strengthening the permafrost climate feedback. Because snowmelt and rain transport some nutrients from land to water, variations in nutrient concentrations within Arctic stream networks can reveal where permafrost nutrients are released and why some areas release more than others. This research greatly improves understanding of how water flow, plant life, and conditions in the soil and bedrock are affected by wildfire, permafrost degradation, and extreme weather conditions. Such knowledge is crucial to protect Arctic communities and forecast how environmental change in the permafrost region could disrupt climate and weather patterns throughout the U.S. This project also transfers improved understanding of the Arctic system directly to the public by creating a network of researchers, writers, performers, and outreach organizations that 1) visits local communities in the Arctic, 2) creates a children?s book inspired by Arctic systems, 3) brings Arctic systems and climate science directly to about 30,000 high school students, and 4) connects remotely with K-12 classrooms in rural Alaska and the contiguous U.S. via video chats.
Collaborators: Ben Abbott (BYU), Breck Bowden (UVM), Arial Shogren (MSU), Jon O'Donnell (NPS)
Funding: National Science Foundation
Selected Products: Shogren et al., 2019; Shogren et al., 2020; Abbott et al., 2021; Shogren et al., 2022 (many presentations at AGU, SFS conferences)
Funding: National Science Foundation
Selected Products: Shogren et al., 2019; Shogren et al., 2020; Abbott et al., 2021; Shogren et al., 2022 (many presentations at AGU, SFS conferences)
Unlocking the Transient Storage Blackbox: Revealing the Role of Less-Mobile Porosity in Hyporheic Denitrification and Greenhouse Gas Production
There is increasing evidence that denitrification and N2O production in streambed sediments is a major control on river greenhouse gas emissions. This research strives to link and quantify transient storage via dual-domain mass transport with the biogeochemical functions of stream sediments. Stream sediments are critical for cleansing anthropogenic nitrate from surface water via denitrification, which reduces nitrate to N2 that returns to the atmosphere. However, it is also increasingly recognized that these processes can produce N2O gas, which has 300x the warming effect of CO2, and is released through incomplete denitrification. Recent global assessments reveal that rivers are major N2O producers, but the mechanism and spatial distribution of production remain unknown. We are exploring the possibility that nitrate reduction occurs predominantly within streambed sediments that are oxic in a bulk sense but have local, anoxic less-mobile pore spaces. Largely overlooked in past work, these anoxic microsites must be mechanistically understood in order to upscale freshwater nitrogen dynamics from point to stream reach, and from stream reach to basin scales. This project brings together laboratory, field, and numerical models that will couple geophysical, solute tracer, and isotopic methods to reveal microsites and their function.
Collaborators: Martin Briggs (USGS), Fred Day-Lewis (USGS), Kamini Singha (Colorado School of Mines), Jud Harvey (USGS), Richard Sheibley (USGS), John Lane (USGS)
Funding: National Science Foundation
Selected Products: Roy Chowdhury et al., 2020, Briggs et al., 2015, Briggs et al., 2018, Hampton et al., 2019 (many presentations at AGU, SFS, HydrEco, and Gordon Research Conferences)
Funding: National Science Foundation
Selected Products: Roy Chowdhury et al., 2020, Briggs et al., 2015, Briggs et al., 2018, Hampton et al., 2019 (many presentations at AGU, SFS, HydrEco, and Gordon Research Conferences)
Flow Regime and Headwater stream controls on river Carbon and Nutrient export
Collaborators: Ben Abbott (BYU), Martin Bouda (Yale University), James Saiers (Yale Univeristy), Peter Raymond (Yale University)
Funding: NSF Early CAREER Program and Yale Institute for Biospheric Studies
Selected Products: Shogren et al., 2021; Zarnetske et al., 2018, Abbott et al., 2017, Ruhala & Zarnetske, 2016 (presented at AGU, SFS, HydrEco, and Gordon Research Conferences)
Funding: NSF Early CAREER Program and Yale Institute for Biospheric Studies
Selected Products: Shogren et al., 2021; Zarnetske et al., 2018, Abbott et al., 2017, Ruhala & Zarnetske, 2016 (presented at AGU, SFS, HydrEco, and Gordon Research Conferences)
Where rivers, groundwater, and disciplines meet: a hyporheic research network
Global environmental change is increasing pressure on the ecosystem services provided by hyporheic zones, the interface between surface water and groundwater. Currently, fragmentation of disciplinary scientific knowledge and the lack of an integrated conceptual process understanding prevent accurate assessment of hyporheic ecosystem functioning and resilience, thereby resulting in ineffective management of these key areas. We propose an international network designed to conceptualize the organizational principles and ecosystem functions of hyporheic zones as important ecohydrological, biogeochemical, and biodiversity hotspots. We will therefore combine unique, supra-disciplinary expertise to pioneer the combination of cutting-edge methodologies in a transferable scientific framework.
|
Collaborators: Stefan Krause (Univ. of Birmingham), Adam Ward (Univ. of Indiana), Scott Larned (National Institute of Water and Atmospheric Research), Thibault Datry (National Research Institute of Science and Technology for Environment and Agriculture), Eugenia Marti (Center for Advanced Studies of Blanes, National Research Council), and Jan Fleckenstein (Helmholtz Centre for Environmental Research)
Funding: The Leverhulme Trust
Selected Products: Schmadel et al., 2016, Kurz et al., 2017, Baranov et al., 2017, Lee-Cullin et al., 2018, Blaen et al., 2018, Kelleher et al., 2019
Funding: The Leverhulme Trust
Selected Products: Schmadel et al., 2016, Kurz et al., 2017, Baranov et al., 2017, Lee-Cullin et al., 2018, Blaen et al., 2018, Kelleher et al., 2019
Climate change impacts on arctic watershed Biogeochemistry and River Icings
The major objectives of these projects are to investigate and predict the responses of Arctic watersheds, stream chemistry, and river icings to changing climatic conditions. Specifically, we study how landscape transfer carbon and nutrients to streams, hyporheic zone dynamics, and river icing features ("aufeis") are all shifting in response to changing seasonality and overall warming in the Arctic.. Each of these shifts has potential major implications on Arctic organisms and global carbon cycling.
|
Collaborators: Breck Bowden (Univ. of Vermont), Ben Abbott (BYU), Tamlin Pavelsky (UNC), Michael Gooseff (Univ. of Colorado), Jim McNamara (Boise State)
Funding: National Science Foundation
Selected Products: Pavelsky & Zarnetske, 2017, Zarnetske et al., 2007, Bowden et al., 2008, Greenwald et al., 2008, Zarnetske et al., 2008
Funding: National Science Foundation
Selected Products: Pavelsky & Zarnetske, 2017, Zarnetske et al., 2007, Bowden et al., 2008, Greenwald et al., 2008, Zarnetske et al., 2008
Role of hyporheic processes on nitrogen cycling in streams
Key objectives of this research are to collect and utilize independent (i.e., geophysical, hydraulic, isotope, and biophysical) characterizations of dominant stream types to: 1. develop integrated methods for overcoming current limitations in groundwater-surface water research and, 2. develop a groundwater-surface water exchange model for water and nitrogen to elucidate hyporheic controls on watershed nitrogen yields. Subsequently, the methods and resulting model can be used to address crucial questions, such as: 1. What are the dominant physical and biophysical controls of the hyporheic zone on nitrogen dynamics?, 2. Can we develop scaling relationships by linking physical and biological controls?, 3. What stream types function as nitrogen sources versus sinks?, 4. Which stream types are most effective at regulating downstream nitrogen export?, and 5. How can we incorporate the self-purification mechanisms of the hyporheic zone in river restoration and management efforts?
Collaborators: Roy Haggerty (Oregon State), Steven Wondzell (Oregon State & USFS), Michelle Baker (Utah State), Ricardo Gonzalez-Pinzon (Univ. of New Mexico, Vrushali Bokil (Oregon State)
Funding: National Science Foundation, USGS Oregon Water Resources Research Institute, Geological Society of America, Society of Freshwater Science
Selected Products: Zarnetske et al., 2011a, Zarnetske et al., 2011b, Zarnetske et al., 2012, Zarnetske et al., 2014, Wondzell & Zarnetske, 2014, Zarnetske et al., 2015
Funding: National Science Foundation, USGS Oregon Water Resources Research Institute, Geological Society of America, Society of Freshwater Science
Selected Products: Zarnetske et al., 2011a, Zarnetske et al., 2011b, Zarnetske et al., 2012, Zarnetske et al., 2014, Wondzell & Zarnetske, 2014, Zarnetske et al., 2015
Other Projects
Solute transport with Conservative and Reactive Transient Storage in rivers
Collaborators: Michael Gooseff (Univ. of Colorado), Robert Payn (Montana State), Alba Argerich (Oregon State), Roy Haggerty (Oregon State)
Funding: National Science Foundation
Selected Products: Payn et al., 2008, Gooseff et al., 2008, Argerich et al., 2011
Funding: National Science Foundation
Selected Products: Payn et al., 2008, Gooseff et al., 2008, Argerich et al., 2011
Hydrogeophysics of streams and valley bottom environments
This collaborative work has been a key part of many surface and groundwater investigations in our research. It has primarily focused on the use of Ground Penetrating
Radar, Electrical Resistivity Imaging, and Fiber Optic Distributed Temperature Sensors to improve spatial and temporal
characterizations of stream subsurface environments.
|
Collaborators: Nigel Crook (HGI, Hydrogeophysics), Martin Briggs (USGS), Troy Brosten (NRCS), John Bradford (Boise State), Roy Haggerty (Oregon State), Michael Gooseff (Univ. of Colorado)
Funding: National Science Foundation, CUAHSI, Inc.
Selected Products: Brosten et al., 2006, Crook et al., 2008, Brosten et al., 2009a, Brosten et al., 2009b,
Funding: National Science Foundation, CUAHSI, Inc.
Selected Products: Brosten et al., 2006, Crook et al., 2008, Brosten et al., 2009a, Brosten et al., 2009b,
IDENTIFYING GROUNDWATER-SURFACE WATER CONNECTIVITY IN A STRONGLY GAINING STREAM ENVIRONMENT, CANTERBURY PLAINS, NEW ZEALAND
In general, lowland strongly-gaining streams are considered to be discharge points for groundwater aquifers. However, there are many mechanisms that create bi-directional ground water - surface water (gw-sw) exchange (e.g., bed topographic and hydraulic conductivity variations). With this in mind, low-land gaining streams may be exhibit more complex gw-sw bidirectional exchange patterns than currently treated in conceptual models. We are using multiple empirical and modelling methods to evaluate the potential for bidirectional dynamics along strongly-gaining lowland streams in the highly heterogeneous alluvial depositional plains of Canterbury, New Zealand. Scale and "window of detection" for gw-sw exchange processes are very important. We are able to quantify gross gains and losses along discrete segments of a gaining stream by taking a nested observation and modelling approach.
Collaborators: Mandy Meriano (University of Toronto), MS Srinivasan (NIWA, Inc., New Zealand)
Funding: pilot funding from NIWA Inc. and NSF IGERT Programs
Funding: pilot funding from NIWA Inc. and NSF IGERT Programs
Effects of waves on solute transport through emergent vegetation
Understanding the interactions between near-shore hydrodynamics and vegetation in coastal areas is necessary to develop strategies for managing and protecting coastal ecosystems and built systems. However, there is little understanding of these interactions. Wave-vegetation interactions are difficult to study in natural settings because collecting and analyzing field data of wave attenuation and fluid flow characteristics in coastal vegetation is logistically and mechanistically complex (e.g., equipment fidelity, dynamic wind speeds and direction, tides, wave refraction and shoaling). Models of wave-plant interactions can be developed, but will be limited until experiments focused on the interactions between waves on real vegetation are completed. Therefore, we are conducting controlled waves and vegetation interaction experiments in a laboratory environment at prototype scale with live plants. These large-scale laboratory experiments are conducted in a Large Wave Flume (104m long, 3.6m wide, and 4.6m deep) at the O.H. Hinsdale Wave Research Laboratory (HWRL) at Oregon State University. Live plants (Schoenoplectus pungens or threesquare bulrush) are collected from the field (Tillamook, Oregon, USA).
Collaborators: Dennis Albert (Oregon State), Dan Cox (Oregon State)
Funding: pilot funding from National Science Foundation, O.H. Hinsdale Wave Research Laboratory
Selected Products: Yoon et al., 2011
Funding: pilot funding from National Science Foundation, O.H. Hinsdale Wave Research Laboratory
Selected Products: Yoon et al., 2011