Lab Research

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Image of a groundwater-surface water tracer experiment tracking flow through a recently deposited gravel bar, which dammed a tributary stream above its historical confluence point.

RESEARCH TOPICS

Our research investigates the biophysical processes of 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 interface between ground and surface waters. 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 watershed hydroecology research are:

* Ground Water - Surface Water Interactions (Riparian and Hyporheic Zones)

* Emergent Patterns in Environmental Biogeochemistry and Aquatic Ecosystems

* Nitrogen and Carbon Export & Retention in Stream Networks (Ecological Flow Regimes)

* Management of Aquatic Ecosystem Structure, Function, and Water Quality

* Arctic and Permafrost Influenced Stream Ecosystems

* Streams, wetlands, and intertidal zones as dynamic transport systems

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HYDROECOLOGY & WATERSHED RESEARCH

List of published research is HERE.

1. FLOW REGIME CONTROLS ON RIVER NITROGEN AND CARBON EXPORT UNDER PAST, PRESENT, AND FUTURE CLIMATE CONDITIONS

The objective of this project is to elucidate how river flow regimes control catchment nitrogen and dissolved organic carbon exports. To achieve this, we are relating hydrologic transport variability to nitrogen and carbon export of major river networks of varying scales under past, present, and predicted future climate regimes. This research strives to reevaluate the ecological theory of nutrient processing in rivers. We are also addressing the classic catchment hydrology questions about source versus transport limitations on riverine DOC and N export, while developing new models to account for the role of flow events in solute and particle export. Furthermore, this project will help develop published ecological-flow relationships at multiple scales that will inform water-quality conservation measures, which in turn conserve freshwater and marine biodiversity, including culturally and economically valued fish, invertebrate, and plant species.

Collaborators:

Martin Bouda (Yale University)

James Saiers, PhD (Yale University)

Peter Raymond, PhD (Yale University)

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2. 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, PhD (Oregon State University)

Steve Wondzell, PhD (Oregon State University)

Michelle A. Baker, PhD (Utah State University)

Ricardo Gonzalez-Pinzon, PhD (University of New Mexico)

Vrushali Bokil, PhD (Oregon State University)

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3. 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 exchange (e.g., bed topographic and hydraulic conductivity variations). With this in mind, low-land gaining streams may be exhibit more complex bidirectional gw-sw 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, PhD (University of Toronto)

MS Srinivasan, PhD (NIWA, Inc, New Zealand)

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4. LINKING GEOPHYSICS AND SMART TRACERS TO COMPLEX STREAM METABOLIC PROCESSES

In this work we seek to use novel electrical resistivity measurement techniques in conjunction with novel metabolically-sensitive hydrologic tracers to identify coupled physical and biological controls on stream and hyporheic metabolism. We hope to assess time-lapse surface and subsurface (hyporheic) solute transport and metabolically active transient storage zones in the stream system. This work is being done in the H.J. Andrews Experimental Forest, LTER site, Oregon, USA.

Collaborators:

Adam Ward, PhD (University of Iowa)

Alba Argerich, PhD (Oregon State University)

Sherri Johnson, PhD (PNWRS, US Forest Service)

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5. 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). To our knowledge, this is the first test using live plants in a controlled, high energy wave environment.

Collaborators:

Dan Cox, PhD (Oregon State University)

Dennis Albert, PhD (Oregon State University)

Heather Smith, PhD (Louisiana State University)

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ADDITIONAL RESEARCH TOPICS

List of published research is HERE.

1. Hydrogeophysics:

This collaborative work focused on the use of Ground Penetrating Radar and Electrical Resitivity Imaging to improve spatial and temporal characterizations of stream subsurface environments.

Collaborators:

Nigel Crook, PhD (HGI, Hydrogeophysics)

Roy Haggerty, PhD (Oregon State University)

Troy Brosten, PhD (NRCS)

John Bradford, PhD (Boise State University)

Michael N. Gooseff, PhD (Penn State University)

2. Solute Transport in Rivers:

This collaborative work focuses on improving our understanding of stream tracer experiments and their ability to differentiate between different sources of transient storage - surface (i.e., pools, eddies) and subsurface (i.e., hyporheic zone)

Michael N. Gooseff, PhD (Penn State University)

W. Breck Bowden, PhD (University of Vermont)

Robert Payn, PhD (Montana State University)

3. Climate Change Impacts on Arctic Streams:

The major objective of this project was to investigate the responses of arctic tundra stream hyporheic zone hydrology and biogeochemical cycling to predicted climate change.

Collaborators:

Michael N. Gooseff, PhD (Penn State University)

W. Breck Bowden, PhD (University of Vermont)

Troy Brosten, PhD (NRCS)

James McNamara, PhD (Boise State Uninversity)

John Bradford, PhD (Boise State University)

Michelle A. Baker, PhD (Utah State University)

John (Jack) C. Schmidt, PhD (Utah State University)

Water connects systems...our hillslopes to our oceans, our terrestrial and aquatic ecosystems, and our industry to our environment.=







  © Copyright 2010 Jay P. Zarnetske |  
    All images contained within © Copyright 2007 Jay P. Zarnetske, unless otherwise specified.