Beaver Creek, Nyack flooplain, Montana (Fall 2017)
Research Objectives
Innovative solutions to water sustainability challenges lie in our ability to effectively manage landscapes to minimize the degradation of water quality. Through our research, we seek to understand how changes in land use and hydroclimatic variability alter:
- the capacity of watersheds to retain and transform nutrients and contaminants
- the timing and magnitude of ecosystem and benthic cyanobacterial productivity in rivers and nearshore lake environments
Current Research
Predicting cyanobacterial proliferations and toxin production in rivers (NSF DEB, NSF Rule of Life)
|
Cyanobacteria growing in freshwater ecosystems, such as lakes and rivers, can produce toxins that pose a risk to aquatic life. We are using high-frequency sensor data paired with field sampling in rivers to inform a series of models testing the relative importance of drivers of cyanobacterial growth and cyanotoxin production in rivers. Read more about the objectives of each project here and here, and learn more about the broader context of this work in a PNAS Inner Workings article by Amy McDermott here.
Jordan Zabrecky and Dre Garcia Jimenez are both conducting their Ph.D. research on this topic and Colette Berkenfield is currently the primary technician on the project. Janette Davidson is investigating environment-species interactions on the Rules of Life project (co-advised by Dr. Shriver), and Modelscape postdoc Laurel Genzoli is involved in this research. |
The influence of stream network expansion-contraction dynamics on watershed biogeochemistry (DOE)
|
The QuEST (Quantifying Ecosystem exports across Space and Time) Project seeks to expand understanding of hydrologic and biogeochemical change in headwater networks that dynamically expand and contract. At UNR, we are focused on the Dog Valley watershed that lies at the interface of the northern Sierras and the Great Basin.
Dre Presswood is conducting his Ph.D. research on this topic. The QuEST project is in collaboration with the Webster Lab (PI), ECOSHEDS lab, Shogren Lab, Speir Lab, and HyDROS Lab, and is in close collaboration with Oak Ridge National Laboratory's WaDE project, Dustin Kincaid, and Hannah Fazekas. Funding is provided by the U.S. Department of Energy's Established Program to Stimulate Competitive Research. |
|
Watershed-to-lake connections in Lake Tahoe (NSF EPSCoR, Nevada Division of State Lands)
Lake Tahoe, Glenbrook, NV (June 2021)
|
Lake Tahoe’s nearshore water quality including algal growth is intimately tied to the internal dynamics within the lake (e.g. mixing and grazing by animals) and the supply of nutrients from the streams and groundwater entering the lake from the watershed. Our goals are to understand the linkage between nitrogen cycling in contributing watersheds and streams to the nearshore algal growth in Lake Tahoe.
Ph.D. student Kelly Loria (funded by an NSF GRFP), postdocs Heili Lowman and Leon Katona (funded by the NSF EPSCoR Modelscape project), and primary technician Jasmine Krause (funded by NDSL) are all conducting research on this topic. |
Controls on the dynamics of river ecosystem energetics (NSF EPSCoR)
Colorado River at Lee's Ferry, AZ (Summer 2019)
Temporal patterns in dissolved gas concentrations in streams have long been used to estimate rates of aquatic ecosystem processes such as primary production and ecosystem respiration to evaluate river health. Yet there still remain observational, computational, and conceptual challenges at the forefront of research on the energetic regimes of rivers.
Modelscape consortium postdocs Heili Lowman investigated controls on continental-scale patterns in river resilience and flood disturbance thresholds (Lowman et al. 2024, PNAS), and postdoc Laurel Genzoli (and former postdoc Leon Katona) is investigating signals of ecological memory in a multi-decadal time series of river ecosystem metabolism from the Truckee River in Nevada.
Other modelscape projects led by Blaszczak with collaborators include:
Modelscape consortium postdocs Heili Lowman investigated controls on continental-scale patterns in river resilience and flood disturbance thresholds (Lowman et al. 2024, PNAS), and postdoc Laurel Genzoli (and former postdoc Leon Katona) is investigating signals of ecological memory in a multi-decadal time series of river ecosystem metabolism from the Truckee River in Nevada.
Other modelscape projects led by Blaszczak with collaborators include:
- (Ongoing) Ecosystem respiration estimations using CO2 isotopes: At a river reach scale, we are developing models of ecosystem respiration using diel carbon isotope fractionation and coupled dissolved carbon dioxide and oxygen models. Collaborators: Bob Hall (Flathead Lake Biological Station)
- Blaszczak, J.R., Yackulic, C., Shriver, R., & R.O. Hall, Jr. Models of underlying autotrophic biomass dynamics fit to daily river ecosystem productivity estimates improve understanding of ecosystem disturbance and resilience. Ecology Letters. https://doi.org/10.1111/ele.14269
Current collaborative research networks:
Collaborative for Research in Aridland Stream Systems (CRASS)
Stream Concentration-Discharge (C-Q) Relationships Network
Dry Rivers Research Coordination Network
StreamPulse
Microbiome Stress Project
Collaborative for Research in Aridland Stream Systems (CRASS)
Stream Concentration-Discharge (C-Q) Relationships Network
Dry Rivers Research Coordination Network
StreamPulse
Microbiome Stress Project
Past UNR Projects:
Patterns and drivers of global riverine hypoxia
While most commonly studied in coastal or lake ecosystems, rivers also experience hypoxic conditions (water column dissolved oxygen concentrations < 2 mg/L). Riverine hypoxia is stressful for aquatic organisms and can alter biogeochemical cycling and contaminant fate and transport. We have compiled a database of dissolved oxygen measurements in rivers around the globe and are using this database to characterizing the spatial and temporal extent of riverine hypoxia, as well as developing an understanding of various riverine hypoxic regimes.
Freshwater salinization patterns and impacts on river ecosystems (2020-2022; Funding: USDA Hatch)
Trends of increasing salinization of rivers due to anthropogenic activities that load excess salts into rivers (e.g. agriculture, mining, road de-icing salting) are globally pervasive. Freshwater salinization can reduce biodiversity, alter the toxicity of specific ions, and disrupt ecosystem function. Changes in the ion composition of freshwater and the timing of ion delivery may alter the capacity of rivers to retain and transform nutrients, carbon, and contaminants. We are using the Walker, Carson, and Truckee river basins in Nevada as model systems to understand the freshwater ecosystem impacts of this global trend. Keenan Seto completed his M.S. thesis on this project and Lauren Bolotin completed a project as a technician in the lab.
Aquatic Macrophytes in Irrigation Canals: Environmental Controls and Impacts on Metabolic Processes (2020-2022; Funding: Bureau of Reclamation)
Excessive growth of invasive aquatic plants (i.e. macrophytes) in flowing waters has negative ecological and economic impacts. We are evaluating the efficacy of UV exposure treatment as an alternative invasive macrophyte control method to the use of herbicides and manual harvesting, while capitalizing on this controlled experiment to explore ecological questions of how greenhouse gas production and ecosystem metabolism change during succession. Meredith Brehob conducted her M.S. on this project (thesis).
Patterns and drivers of global riverine hypoxia
While most commonly studied in coastal or lake ecosystems, rivers also experience hypoxic conditions (water column dissolved oxygen concentrations < 2 mg/L). Riverine hypoxia is stressful for aquatic organisms and can alter biogeochemical cycling and contaminant fate and transport. We have compiled a database of dissolved oxygen measurements in rivers around the globe and are using this database to characterizing the spatial and temporal extent of riverine hypoxia, as well as developing an understanding of various riverine hypoxic regimes.
- Blaszczak, J.R., Koenig, L.E., Mejia, F.H., Gómez-Gener, L., Dutton, C.L., Carter, A.M., Grimm, N.B., Harvey, J.W., Helton, A.M., Cohen, M.J., Anyanwu, E.D., Pokrovsky, O.S., Krickov, I.V., Manasypov, R.M., Vorobyev, S.N., and Serikova, S., 2021, Distribution, frequency, and global extent of hypoxia in rivers: U.S. Geological Survey data release, https://doi.org/10.5066/P99X6SIR.
- Blaszczak, J.R., Koenig, L.E., Mejia, F.H., Carter, A.M., Gómez-Gener, L., Dutton, C.L., Grimm, N.B., Harvey, J.W., Helton, A.M., & M.J. Cohen. Extent, patterns, and drivers of hypoxia in the world's streams and rivers. Limnology & Oceanography Letters. https://doi.org/10.1002/lol2.10297
Freshwater salinization patterns and impacts on river ecosystems (2020-2022; Funding: USDA Hatch)
Trends of increasing salinization of rivers due to anthropogenic activities that load excess salts into rivers (e.g. agriculture, mining, road de-icing salting) are globally pervasive. Freshwater salinization can reduce biodiversity, alter the toxicity of specific ions, and disrupt ecosystem function. Changes in the ion composition of freshwater and the timing of ion delivery may alter the capacity of rivers to retain and transform nutrients, carbon, and contaminants. We are using the Walker, Carson, and Truckee river basins in Nevada as model systems to understand the freshwater ecosystem impacts of this global trend. Keenan Seto completed his M.S. thesis on this project and Lauren Bolotin completed a project as a technician in the lab.
- Bolotin, L., Savoy, P., Summers, B., & J.R. Blaszczak. Classifying freshwater salinity regimes in central and western U.S. streams and rivers. Limnology & Oceanography Letters. https://doi.org/10.1002/lol2.10251
- Bolotin, L. A., & J. R. Blaszczak. 2022. Freshwater Salinity Regimes, HydroShare, https://doi.org/10.4211/hs.f17ac03970cb4160bd7bd0945c20f0ba
- Seto, K., & J.R. Blaszczak. Pulsed and pressed: Stream sediment biogeochemical responses to variable salinity regimes exposure in a laboratory mesocosm experiment. In prep.
Aquatic Macrophytes in Irrigation Canals: Environmental Controls and Impacts on Metabolic Processes (2020-2022; Funding: Bureau of Reclamation)
Excessive growth of invasive aquatic plants (i.e. macrophytes) in flowing waters has negative ecological and economic impacts. We are evaluating the efficacy of UV exposure treatment as an alternative invasive macrophyte control method to the use of herbicides and manual harvesting, while capitalizing on this controlled experiment to explore ecological questions of how greenhouse gas production and ecosystem metabolism change during succession. Meredith Brehob conducted her M.S. on this project (thesis).
- Brehob, M., Chandra, S., & J.R. Blaszczak. Controls on ecosystem productivity and aquatic plant community dynamics in agricultural irrigation canals in the semi-arid U.S. Submitted.
- Chandra, S., Blaszczak, J.R., Brehob, M., Paoluccio, E., & J. Paoluccio. 2023. Data and Report from S&T Project 20041: Aquatic macrophytes in seasonally-dry irrigation canals: environmental controls and impacts on metabolic processes. https://data.usbr.gov/catalog/4700
Click for additional past research projects!
