Staff Research

St. Croix River Watershed

Updating the Monitoring Plan for the St. Croix River

The “Monitoring Plan for the St. Croix River” was developed by the St. Croix Basin Water Resources Planning Team (Basin Team) in response to a 2006 interagency agreement between Wisconsin Department of Natural Resources (WDNR) and Minnesota Pollution Control Agency (MPCA) to reduce phosphorus (P) inputs to Lake St. Croix by 20% by the year 2020.  The original 2006 monitoring plan was designed to track progress toward achieving that goal. However, the Basin Team has come to the conclusion that: 1) the existing monitoring plan needs adjustment (beyond P) based on an improved understanding of the internal processes by which Lake St. Croix functions as an integrator of basin-wide activities, 2) the guidance document needs to expand into a “monitoring and assessment” plan, and 3) the St. Croix River basin is exposed to certain emerging threats that also need monitoring and assessment.

Research Station staff will update the monitoring plan based on guidance from members of the Basin Team. An updated plan will retain key elements of the original plan: 1) outline of an ideal monitoring network for meeting the updated needs, 2) follow-up Gap Analysis of existing interagency cooperative monitoring activities, and 3) prioritization of the remaining needs, providing actionable items for the near future. Changes to the plan will include: 1) expanded (beyond P) emphasis of monitoring efforts on ecosystem response throughout the St. Croix basin, 2) incorporation of pre-emptive monitoring for emerging threats to the St. Croix and its tributaries, and 3) added prioritization of coordinated assessment efforts.  Throughout, National Park Service staff will provide oversight to ensure that the updated plan meets the needs and requirements of NPS. Funded by the National Park Service. Staff contact: Sue Magdalene 

From seed to seed: A multi-generational approach to increasing the resilience of agricultural, natural, and social landscapes

Faculty and students at the University of Wisconsin-River Falls are working to broaden understanding of decision-making about sustainable land management practices. Agricultural producers have strong social and economic incentives to continue expanding their acreage and intensifying their practices. The average citizen is caught between recognition of the economic need for agricultural production and awareness of its potential threats to environmental quality. Research is needed at the interface of these complex worlds and situations in order to facilitate a multi-directional flow of information, ideally resulting in effective policy development and on-the-ground changes to land management. 

Through research, education, and outreach, this project seeks to expand the acreage of native perennial prairie species within existing agricultural landscapes to help restore ecological function, thereby improving habitat availability, soil health, and water quality.  Scientists at the Research Station will complete two components of this larger project:

  1. A computer model of the Kinnickinnic River watershed will be developed to help predict the consequences of different land-use practices on water quality.  The model will be calibrated to present conditions to set the stage, and then different agricultural practices will be inserted into the model to assess changes in the delivery of sediment and nutrients to the Kinnickinnic River.  Which types of conservation practices are most effective in improving water quality? 

  2. Research Station scientists will provide presentations to local and regional stakeholders on market-driven strategies to improve water quality and expand wildlife habitat.  While the watershed model may identify effective conservation practices, not all of these are equally feasible to implement by farmers, who are faced with trying to keep their family businesses viable.  Can we find those practices that hit the sweet spot of being both economically and environmentally beneficial?  

The project will evaluate potential benefits and barriers to restoring ecological function to agricultural and natural landscapes, particularly through the use of intercropping perennial vegetation and ground covers.  Research knowledge will be integrated into high-impact learning experiences for undergraduates including a transdisciplinary land management course and research internships. Research knowledge will also be used to develop youth summer camps and workforce development programming for middle school, high school, and college age youth from communities underrepresented in STEM and agriculture in collaboration with regional informal science education organizations, Carpenter St. Croix Valley Nature Center and Science Museum of Minnesota. Funded by the U.S. Department of Agriculture, National Institute of Food and Agriculture; subcontract from University of Wisconsin-River Falls. Staff contacts: Jim Almendinger, Shawn Schottler

Tanglewood Preserve habitat restoration

The spread of buckthorn has severely degraded the habitat value and ecological function on large portions of Research Station lands.   The University of Minnesota is involved in several efforts to test new long-term control methods of buckthorn and has sought sites where infestations could be cleared, followed by the testing of strategies to suppress subsequent regeneration from the seed bank.  The project involves management of Station land holdings, use of those lands for novel buckthorn management research, and a demonstration site of restoration techniques to the community. Funded by the Minnesota Department of Natural Resources, with cooperation from the University of Minnesota and Stantech Corporation. Staff contact: Shawn Schottler

Paleolimnological study in the Comfort Lake-Forest Lake Watershed District, Chisago and Washington counties, Minnesota

This project is using paleolimnological techniques to reconstruct the trophic, sedimentation and ecological history of several lakes with current elevated nutrient levels in the Comfort Lake-Forest Lake Watershed District in Chisago and Washington counties, Minnesota. Dated sediment cores from a list of strategically chosen lakes in the district will be analyzed using geochemistry, sediment accumulation, diatom-inferred total phosphorus (DI-TP), and diatom communities and fossil algae pigments as biological indicators.  Results will provide a history of ecological changes that have occurred in the lakes during the last 150-200 years. Knowledge of the natural state of a lake and an understanding of the timing and magnitude of historical ecological changes will be critical components for management and remediation plans. Funded by the Comfort Lake-Forest Lake Watershed District. Staff contact: Mark Edlund

Lake St. Croix nutrient loading and ecological health assessment

This project has two overall goals. The first is to improve existing phosphorus mass-balance estimates for Lake St. Croix. Measurements of phosphorus outflows are now possible with the flow gage on the St. Croix River at Prescott, WI, but mainstem inflows must be estimated by scaling the flow record measured at St. Croix Falls, WI. This project will install a new USGS flow gage on the St. Croix River at Stillwater, MN. In addition, previous estimates of internal loading were based on the assumption of dominantly oxic conditions in Lake St. Croix, an assumption that has come under question with increasing evidence of anoxic conditions in depth profiles. The second goal of this project is an improved understanding of the relationship between water quality and ecological health of Lake St. Croix. The 20% phosphorus reduction goal is derived from conditions that were last recorded in lake cores during the 1940s, and is expected to restore Lake St. Croix to benthic algal dominance. Phosphorus concentrations in Lake St. Croix have declined by an average of 0.2 μg/L per year during the period 1976-2004, but the response variable chlorophyll has lagged behind these improvements. The study is monitoring the direct response of chlorophyll and algae biomass to seasonal changes in lake nutrient concentrations to develop a predictive relationship between bioavailable nutrient supply and planktonic chlorophyll. Changes in nutrient concentrations will be related to changes in external loading from upstream and internal loading from sediments estimated under the first goal, providing a basis for estimating the future success of TMDL implementation controlling plankton chlorophyll in Lake St. Croix. Funded by: St. Croix River Association. Staff contact: Sue Magdalene

Watershed modeling of phosphorus reductions from agricultural BMPs in the St. Croix basin

Lake St. Croix, the lowermost 40 km of the St. Croix National Scenic and Recreational Riverway, is impaired by eutrophication from excessive phosphorus loads.  These loads come largely from nonpoint sources scattered across the 20,000 km2 basin, which straddles the Minnesota-Wisconsin border.  To address this impairment, the states authored a total maximum daily load (TMDL) study that set a goal to reduce phosphorus loads to Lake St. Croix by 27%.  We constructed a computer model of the St. Croix basin with the Soils and Water Assessment Tool (SWAT) to estimate possible reductions of phosphorus and sediment loads that might accrue from implementation of agricultural best management practices (BMPs), thus testing the feasibility of achieving the goal set forth in the TMDL study. 

In the model, BMPs were applied to tilled cropland in the basin, namely corn-alfalfa (CA) or corn-soybean (CS) rotations, each of which occupied about 6% of the basin.  Loads of phosphorus entering Lake St. Croix were reduced in the model by up to 4% for no-till (NT) scenarios, 3% for vegetated filter strip (VFS) scenarios, 6% for grassed waterway (GWAT) scenarios, and 5% for reduced initial soil-test phosphorus (STP) scenarios.  Implementation of fall cover crops (FCCs), which provides cover of large parts of the landscape formerly protected only by crop residue, resulted in larger reductions of phosphorus loads, up to a 23% reduction if FCCs were fully implemented following all corn and soybean crops in all rotations.  Improved soil health (ISH) was modeled as an incremental variant of the FCC scenarios, which reduced phosphorus loads reaching Lake St. Croix by a few additional percent, up to 25% reduction.  These results indicate that achieving the TMDL goal of a 27% reduction in phosphorus loads entering Lake St. Croix may be difficult with agricultural BMPs alone, requiring essentially full implementation of FCCs on all cropland.  Establishment of more living cover, whether as FCCs or perennials, will almost certainly be part of the solution.  Funded by National Park Service and the St. Croix Basin Water Resources Planning Team. Staff contact: Jim Almendinger

Minnesota Lakes and Rivers

Historical changes in Upper and Lower Red Lakes in Beltrami and Clearwater Counties, Minnesota

Upper and Lower Red Lake feature prominently on our Minnesota maps but have been little studied, especially with regard to how they may have changed following European settlement. Station research efforts on nearby Lake of the Woods also provide a companion dataset on how other large, shallow lakes are responding to more recent drivers of change including management and climate change. This project will use multiproxy paleolimnological techniques to reconstruct the trophic and sedimentation history of both Upper and Lower Red Lakes.  Results will provide a management foundation by determining the natural or reference condition of these lakes and by reconstructing a history of ecological changes that have occurred in the lakes during the last 120 years. Funded by the Red Lake Nation. Staff contact: Mark Edlund

Completing the National Wetland Inventory Update for Minnesota: Wetland functional assessment demonstration and training for data users

Wetlands provide critical ecosystem services such as mitigating floods, improving water quality, and providing habitat.  Currently, the National Wetlands Inventory Update project of the Minnesota DNR is mapping wetlands with unprecedented accuracy, given advances in aerial imagery and topographic details.  Each mapped wetland is classified according to its vegetation stature and assumed hydrologic connections, and consequently some ecosystem services can be inferred.  However, many important details of wetland hydrologic function remain unknown.  Which wetlands recharge groundwater?  Which wetlands are best at filtering nonpoint source pollutants washing off the uplands?  How much water can be ponded behind selected wetlands?  Because hydrology is such a critical driver of all these wetland processes, we will explore how to use the new high-accuracy LiDAR elevation data sets to determine hydrologic characteristics of wetlands in order to better relate the current wetland classification to their ecosystem services.  Our results will be written into a user manual and presented to resource managers for application in their own study units. Funded by the Minnesota Dept. of Natural Resources. Staff contact: Jim Almendinger

Intensified tile drainage evaluation

Vast areas of Minnesota have been extensively altered with artificial drainage, including sub-surface tile, ditches, wetland drainage, and surface inlets. The effect of these manipulations in altering hydrology and sediment erosion is not well understood. Sediment cores from Lake Pepin provide an integrated historical record of erosion rates in Minnesota. Sediment accumulation rates have increased by nearly tenfold since European settlement and are currently dominated by erosion of non-field sources such as streambanks, bluffs and ravines. The increase in non-field sources coincides with the intensification of artificial drainage and with periods of increased precipitation. The impacts of artificial drainage networks on destabilizing near-channel sediment sources and increasing riverine sediment loads cannot be examined until the installation history and density is inventoried. Equipped with the knowledge of how tile density varies among watersheds, it will be possible to do comparative assessments of long-term changes in hydrology in watersheds with and without artificial drainage, and relate these effects and temporal trends to the observed sedimentation rates in Lake Pepin. Specifically this project will (1) Quantify artificial drainage density and extent in ∼23 watersheds contributing to Lake Pepin and estimate the time trends of installation; (2) Provide a comparative assessment of changes in 14 hydrologic parameters in watersheds with and without intensive artificial drainage to determine the effect of drainage and precipitation in changing river hydrology/erosive potential; and (3) Estimate the role of drainage in accelerating non-field sediment erosion by correlating time trends of artificial drainage and precipitation/climate to the historical sediment loading trends in Lake Pepin. Funded by: LCCMR and Environmental Protection Agency. Staff contacts: Shawn Schottler, Dan Engstrom, and Jim Almendinger

Evaluation of the sulfate standard to protect wild rice in Minnesota lakes

The St. Croix Watershed Research Station in collaboration with scientists at the University of Minnesota will: (1) plan and execute a sampling program for water and sediments to help evaluate potential environmental factors important in the distribution and abundance of wild rice in Minnesota lakes, and (2) evaluate methods for effective sampling and analysis of sediment pore-waters for chemical constituents important to wild rice distribution and abundance. The data and information gained from this study will inform further evaluation of Minnesota's sulfate water-quality standard for the protection of wild rice. The study will document the range of water-column and sediment chemistries at sites with robust, declining, and absent wild rice stands in lakes and flowages throughout the northern and central regions of the State. These results will be combined with laboratory growth experiments to determine the relationship(s) between surface-water sulfate, porewater chemistries, and wild-rice survival and growth. Funded by Minnesota Pollution Control Agency. Staff contacts: Dan Engstrom

Lake of the Woods historical phosphorus

Elevated nutrients and their biological consequence – increased frequency and extent of cyanobacterial blooms – continue to dominate resource concerns for Lake of the Woods (LoW). The conundrum is that there is a well-documented decrease in nutrient loading to the lake, which should have mitigated nutrient and blue-green problems. Monitored inputs of phosphorus from LoW's major tributary, the Rainy River, have decreased in the last 30 years, and point source loadings have declined, yet comparison of monitored water quality variables between the 1980s and 2000s show little change in most in-lake nutrients. In this project we will use whole basin seismic mapping and analyze 8-12 sediment cores from Lake of the Woods for multiple geochemical and biological lines of evidence to determine the historical sources, fate, and impacts of phosphorus (P) loading. Results will be synthesized to generate a whole basin and historical model of nutrient loading, nutrient burial, and in-lake nutrient levels that will answer these management questions: (1) How has P loading to LoW changed over the last 100 years relative to background or pre-European levels? (2) How have biological communities (cyanobacteria and diatoms) changed over the last 100 years? (3) Are trends in biological communities, nutrient dynamics, and sedimentation related to changes in external nutrient loading? (4) Do trends in biological communities, nutrient dynamics, and sedimentation reflect legacy nutrient effects? Funded by Minnesota Pollution Control Agency. Staff contact: Mark Edlund

Sedimental Journey: Watershed-scale monitoring of long-term best-management practice effectiveness

Minnesota has widespread water-quality impairments due to nonpoint-source (NPS) pollution generated by agricultural, urban, and other human-altered lands.  Mitigation of these impairments requires implementing best-management practices (BMPs) that are designed to limit soil erosion and nutrient transport from lands to receiving waters.  Long-term data sets of water quality and land-use history that span periods before and after BMP implementation are needed to determine BMP effectiveness.  However, such data sets are lacking, because water-quality monitoring of our lakes and rivers did not begin until well after humans altered the landscape.  In this project, we will fill this data gap by constructing long-term water-quality records as preserved in lake sediments. 

We’ve selected ten lake-based watersheds from the agricultural regions of Minnesota for a detailed assessment of whole watershed loads of sediment and nutrients, as determined from multiple sediment cores collected from each lake.  Our team of scientists are applying a comprehensive suite of proven analytical tools such as radioisotopic dating, sediment fingerprinting, algal analysis, and diatom reconstruction to determine the changes in pollutant loading over long periods of time, most critically before and after BMP implementation.  In addition, our lab brought a new capability to Minnesota by establishing the Center for Harmful Algal Research in Minnesota.  The CHARM lab uses a specialized (inverted) microscope to identify algae in current noxious blooms and to develop novel techniques to document these blooms over time in the sediment record. 

The chronology of these loads and blooms as determined from the sediment record will be compared against the history of land use and BMP implementation in each basin to search for statistical correlations.  Finally, watershed computer models will be fit to these basins as constrained by the long-term data extracted from the sediment-core records, thereby both testing and improving the models.  The benefits include development of critical long-term data sets, a test of BMP effectiveness at the watershed scale, and improvement of modeling tools to make results more realistic and predictive.  The long-term data sets will greatly enhance the value of existing watershed monitoring in the state by providing temporal context, without which the current records are unanchored relative to natural, pre-industrial conditions.  Funded by Environment and Natural Resources Trust Fund as recommended by the Legislative and Citizen Commission on Minnesota Resources.  Staff contacts: Jim Almendinger, Dan Engstrom

Great Lakes Region

Biomonitoring prospects for diatoms and paleolimnology in the Western Great Lakes National Parks

In Great Lakes Network (GLKN) National Park units, climate change, environmental contaminants, exotics, and land and resource uses including shoreline and urban development, recreation, water level management, logging, and agriculture have raised concerns about the state of the parks' resources and how to best manage them in a future certain to bring change. In this project we developed a strategy to integrate the use of paleolimnological techniques and diatom analysis in an inventory and monitoring framework. Results will provide a management foundation by determining the natural variability or reference condition of national park lakes. Because lake-sediment records integrate across both spatial and temporal scales, research results will be further used as a biomonitoring strategy by revisiting lakes on regular intervals (3-5 years) to quantify modern environmental conditions relative to historical conditions, to detect early ecological change and recent trends, and to evaluate success of management actions. Funded by National Park Service-GLKN. Collaborators: National Park Service. Staff Contact: Mark Edlund

National and International Watersheds

Diatoms of the United States

Diatoms are microscopic algae that live in nearly every fresh- and salt-water environment, serving as the base of many food chains and providing a quarter of the oxygen we breathe. With rich diversity and distinctly ornate, robust, silica shells, different species of diatoms prefer varying ecological habitats that makes them useful indicators of modern and paleo environmental conditions. In order to create a peer-reviewed identification guide the website, Diatoms of the United States (DOTUS), has been created in collaboration by the U.S. Geological Survey, U.S. EPA, the Research Station, and other scientists.

At the Station, Mark Edlund and University of Minnesota graduate student David Burge are utilizing the archived diatom collections from previous projects to develop species identification webpages. These webpages display research grade images of the diatoms taken by microscopes in the Station’s diatom lab. A written description, ecological information, and comparative diagnosis to similar species is also provided for each webpage. Lastly, a digital copy of the original description of the diatom species is provided from the Station’s library, sometimes obtained from literature written over 150 years ago!  In addition to generating over 150 genera and species pages, Mark and David review species pages generated by other scientists as part of the publication process.

The free nature of DOTUS allows taxonomists, analysts, and researchers from private, academic, and government institutions across North America to access a detailed, peer-reviewed, diatom identification resource. You can learn more about diatom ecology, identification, and diversity at DOTUS: Staff contact: Mark Edlund

Using triclosan and polyhalogenated dibenzo-p-dioxins to elucidate the importance of natural and anthropogenic sources of OH-PDBEs in fresh and estuarine waters

For the past 20 years soap manufacturers have added the bactericide, triclosan, to liquid hand soaps and other personal care products. However, recent scientific findings raise questions about unintended consequences of widespread triclosan use. It appears that a portion of the triclosan that goes down our drains is discharged to surface waters, where it is transformed by sunlight into dioxins, an infamous class of toxic pollutants. Two studies are exploring the extent of triclosan-dioxin pollution in Minnesota and beyond. These studies are a collaborative effort between scientists at the University of Minnesota, ETH-Zurich (Switzerland), and the Research Station. Much of the focus will be on sediment-core records of historical dioxin pollution from lakes and estuaries receiving wastewater discharge. In Minnesota, that includes Lake St. Croix, Lake Pepin, the Duluth-Superior Harbor, Lake Superior, and a number of smaller lakes. The overall aim of the studies is to quantify the relative importance of triclosan and related compounds such as PDBEs (flame retardants) to the total dioxin contamination of our surface waters. Funded by: National Science Foundation and Legislative Citizens Commission on Minnesota Resources. Staff contact: Dan Engstrom