Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) Completed
For 43 years, the Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) brought together scientists from the USGS along with students and professors from universities in Minnesota, North Dakota, Wisconsin, and California to study the physical, chemical, and biological processes of lakes, wetlands, and streams at local and watershed scales. In early 2022, The University of Minnesota and Bemidji State University took over this project and will continue this important work in the future.
Current Status
In early 2022, responsibility for the Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) was transferred to The University of Minnesota and Bemidji State University. The information below is being preserved for historical reference, but is no longer current. For up-to-date information about the project, please contact Leslie Ludtke (ludtk028@umn.edu), Joe Magner (jmagner@umn.edu), or Miriam Rios-Sanchez (Miriam.Rios-Sanchez@bemidjistate.edu).
Historical Overview
The Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) brings together scientists from the U.S. Geological Survey, and students and professors from universities in Minnesota, North Dakota, Wisconsin, and California for a unique and cooperative study opportunity. This diverse group of scientists conducts research on physical, chemical, and biological processes of lakes, wetlands, and streams and investigates interfaces (air-water, air-land, land-water) on local and watershed scales. Scientists who might not normally work together learn from each other's approaches and develop new ideas for collaborative research. Each highly specialized study adds to a collective body of information that leads to a better understanding of the processes that occur in and adjacent to lakes, wetlands, and streams. By focusing on the interfaces of these multiple scientific disciplines, SHAEP hopes to provide a broader scientific perspective than could be achieved without such a cooperative integration. The Shingobee River Fact Sheet provides more detailed information about the site location and specific research goals.
Interdisciplinary research is not a new idea, but it was rarely accomplished in 1989 when this study began. The prospect was so novel that this effort initially was known as the Interdisciplinary Research Initiative, or IRI. IRI was changed to SHAEP to better reflect the site location and the overarching goals of the research conducted there.
Brief History of the Project
In 1987 a group of scientists from the former National Research Program of the Water Resources Division of the US Geological Survey met to discuss the state of watershed science. The committee agreed that proper management of our Nation's water resources required knowledge of how atmospheric water, surface water, and ground water function as integrated systems. It was obvious that an interdisciplinary approach to studying lakes and watersheds was needed. The committee decided to focus initially on lakes, because lakes are a natural integrator of hydrologic processes. Rather than focus these efforts on one lake, with the hope that the information learned about this lake would transfer to other lakes the committee decided to select a paired-lake site, where two nearby lakes would have greatly different water and chemical residence times. By studying two lakes, and comparing the results, they would be able to determine which processes were important to both lakes, and which were unique to one or the other lake.
A nationwide search resulted in the selection of the upper Shingobee River watershed located in north-central Minnesota. This watershed offered two lakes that had greatly different hydrologic settings even though they were close to each other. Several different types of wetlands offered a broad scope of wetlands research, and the headwaters of the Shingobee River presented a great opportunity for in-stream and riparian-corridor-scale research. Research to date has focused on Williams Lake and Shingobee Lake, as well as on processes occurring along the Shingobee River and within a nearby fen.
Shingobee Field Station
Dallas Hudson is the resident technician based at the Shingobee Field Station. Dallas collects hydrologic, atmospheric, biological and water-quality information that constitutes the data backbone of the SHAEP effort. Dallas is available to assist with project-specific data-collection efforts as time allows.
With the exception of Dallas, all who work at the SHAEP do so on a part-time and voluntary basis. Each has other duties and commitments, but all come to work at the Shingobee site to learn from colleagues with different perspectives, and make new discoveries about the SHAEP lakes and the land around them.
Amenities at the Shingobee Field Station include:
- Wireless access to internet
- Two bedrooms for visiting scientists
- Kitchen, laundry, storage
- Direct access to Shingobee Lake
- 3-season meeting room
- Boat available to those with USGS motorboat-safety training
- Assistance from Dallas Hudson can be arranged
Current Research
Current interdisciplinary research is focused on three main topics:
- Processes associated with the carbon budgets of the two lakes
- Physical, chemical and biological processes in the Little Shingobee Fen
- Physical, chemical and biological processes along the Shingobee River
Refinement of hydrologic budget for Shingobee Lake (Rosenberry, Hudson)
The "Great Wall of Shingobee" at the outlet to Shingobee Lake was working well to restrict and accelerate very slow flow at the outlet to allow us to make accurate measurements of stream discharge from Shingobee Lake. In spite of Dallas’s Herculean efforts to keep beaver dams at bay, the ever persistent critters built large dams well downstream, out of Dallas’s reach. Flow at the outlet slowed to the point where accurate discharge measurements were no longer possible. An extension of the great wall did the trick and we are back in business.
Temporal and spatial variability in discharge of springs (Rosenberry, Hudson)
Groundwater discharge to Shingobee Lake via numerous near-shore springs continues to vary over time in ways that are not always related to weather or lake stage. We are in the process of collecting water-quality samples from several of the springs in an effort to determine ages and flow paths for ground water discharging from the springs. A MODFLOW groundwater-flow model is in need of further refinement should someone be interested in joining this effort.
Source of carbon to Shingobee Lake (Striegl et al.) Gas-flux research (Dornblaser et al.)
Rob Striegl and Mark Dornblaser continue to home in on quantifying several of the carbon fluxes associated with Williams and Shingobee lakes. Manual and/or synoptic-scale measurements are needed to support data provided by gas-flux sensors installed on rafts deployed in Williams and Shingobee Lakes.
Lake sediment chemistry (Schuster et al.)
Paul Schuster and colleagues published a paper in 2003 in Hydrological Processes in which they characterized and contrasted the chemical characteristics of the shallow, near-shore sediments of Williams Lake in an area where ground water discharges to the lake, and another area where lake water flows to the groundwater system. That was then; this is well over a decade later. It would be very interesting to repeat this study to see what processes continue and what has changed with increasing open-water periods and evolving ecosystems.
Paleolimnology (in need of a new lead)
Several papers were published in 2003 related to the paleolimnology of the site. Walter Dean and colleagues discussed the effect of groundwater on accumulation of iron and manganese in the deep-lake sediments (Dean et al., 2003, Ground Water). Sheryl Filby and company modeled the hydrology of the site during the mid-Holocene (Filby et al., 2003, Quaternary Research). Antje Schwalb reported on lacustrine ostracodes related to climate dynamics during the Holocene (Schwalb, 2003, Journal of Paleolimnology). After that, emphasis shifted to Steel Lake, situated between Williams and Shingobee Lakes, where varved sediments presented a fantastic view into the post-glacial past (Nelson et al., 2004, Proceedings of the National Academy of Sciences; Nelson et al., 2007, Microbial Ecology; Nelson et al., 2008, New Phytologist; Tian et al, 2005, The Holocene; Tian et al., 2006, Geophysical Research Letters; Wright et al., 2005, Quaternary Science Reviews). Walt Dean and Lisa Doner then moved the focus to Little Shingobee Lake and adjacent fen, where sediment cores yielded pollen and geochemical evidence that the lake ecosystem was changing profoundly to a changing climate as the prairie-forest boundary transitioned past the site (Dean and Doner, 2012, Journal of Paleolimnology). Their results are directly relevant to what appears to be a rapidly changing climate at the site right now.
Glacial mapping (Melchior)
Bob Melchior completed his long-awaited USGS report on the glacial history of the Shingobee headwaters area (Melchior, 2014, USGS SIR). Melchior reports that a large glacial lake occupied nearly the entire Shingobee watershed until an ice-cored dam broke, creating a catastrophic flood that eroded the large valley through which the modern-day Shingobee River flows. Bob also discusses the creation of sub-glacial tunnel valleys and eskers just north of Shingobee Lake. The carving out of nearby Leech Lake along with the associated creation of large hills between Leech Lake and Shingobee Lake a “hill-hole pair,” is a new concept advanced by Bob. If this paper isn’t fascinating enough, a road log of the geology of northern Minnesota, including the Shingobee site, extends the glacial picture to well beyond the Shingobee headwaters area (Rosenberry et al., 2011, Geological Society of America Field Guide).
Survey of vegetation type related to hydrologic setting (Melchior)
Bob Melchior has shifted from geology to botany as he continues his research in the Shingobee headwaters area. Bob is always looking for field help should anyone care to assist with this effort.
Growth rate of northern pike in Shingobee Lake (Hudson, Carlson)
Imagine catching a 39-inch northern, wrestling it into the boat, recording the tag number, length, girth, weight, and then tossing it back in the water; and then catching another just like it later in the same day. This is an ichthyologists’ dream and this happens on a regular basis at Shingobee Lake. Some of these lunkers have been caught nearly 20 times. Little did we know that Dallas, in part due to these pursuits, is the most interesting man in Minnesota, but the proof is in a feature article in the Sunday Minneapolis Tribune (Tribune link from the NRP web pages here). Dallas Hudson keeps this study going in his spare time and Bruce Carlson, retired research scientist from the University of Michigan and current resident of nearby Ten Mile Lake, makes sense of the plethora of data produced by the 10,000 or so tagged northerns. Andy Hafs from Bemidji State and his graduate student, John Kempe, have recently joined the effort.
Phenology of the Shingobee headwaters area (Hudson)
Dallas Hudson records first sightings, numbers, last sightings, and several other phenological observations for several hundred species of mammals, insects, and flora. We are in need of someone to help make sense of all these valuable data that contain some very interesting trends. Dallas also has been the first observer of several species in Hubbard County, several of which have never been observed so far north.
Research of lakes, streams and wetlands in a small-watershed setting
Watershed-scale research has been a significant component of hydrologic and ecological disciplines for many decades, and small-watershed studies have been especially common and useful because of their scale. It is much easier to quantify processes, assess heterogeneities and extrapolations of results, and scale those results when studying a watershed that is relatively small. The Upper Shingobee watershed is only 28 square kilometers in area and much of the research is focused on subwatersheds within the Shingobee headwaters area. An overview of research highlights from studies conducted at Williams Lake, Shingobee Lake, the Shingobee River upstream of Shingobee Lake, and the Little Shingobee Fen, was presented at the First Interagency Conference on Research in the Watersheds during Fall 2003 (Rosenberry et al., 2003, Conference proceedings), and serves as a template for continuing ecosystems research opportunities at Shingobee.
Available Data from the Shingobee Site
Much data has been collected from the Shingobee site since its inception. Some data are collected only once or infrequently during synoptic studies for special research interests. However some data are collected during regular intervals and include:
- climate data
- water-chemistry data from Williams Lake, Shingobee Lake and the Shingobee River
- hydrology data
While some data have not yet been processed, checked for errors, or analyzed, many of these data are available upon request. Please contact Richard Webb (rmwebb@usgs.gov) with request for climate, water-chemistry or hydrology data.
Selected USGS Publications from the Shingobee Headwaters Aquatic Ecosystems Project appear below. You can also download a complete bibliography for the project.
Watershed-scale research from many perspectives : the Interdisciplinary Research Initiative at the Shingobee River headwaters area, Minnesota
DIN retention-transport through four hydrologically connected zones in a headwater catchment of the Upper Mississippi River
Hydrologic response of the Crow Wing Watershed, Minnesota, to mid-Holocene climate change
Comparison of local- to regional-scale estimates of ground-water recharge in Minnesota, USA
Effect of humic substance photodegradation on bacterial growth and respiration in lake water
Comparison of wetlands in different hydrogeological settings under conditions of extreme climate variability
Integrating seepage heterogeneity with the use of ganged seepage meters
Comparison of 13 equations for determining evapotranspiration from a prairie wetland, Cottonwood Lake Area, North Dakota, USA
Characterization of lake water and ground water movement in the littoral zone of Williams Lake, a closed-basin lake in North central Minnesota
Inorganic nitrogen transformations in the bed of the Shingobee River, Minnesota: Integrating hydrologic and biological processes using sediment perfusion cores
The lacustrine carbon cycle as illuminated by the waters and sediments of two hydrologically distinct headwater lakes in north-central Minnesota, U.S.A
Reconstruction of hydrological changes and response to effective moisture variations from North-Central USA lake sediments
Mid-Holocene hydrologic model of the Shingobee watershed, Minnesota
- Overview
For 43 years, the Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) brought together scientists from the USGS along with students and professors from universities in Minnesota, North Dakota, Wisconsin, and California to study the physical, chemical, and biological processes of lakes, wetlands, and streams at local and watershed scales. In early 2022, The University of Minnesota and Bemidji State University took over this project and will continue this important work in the future.
Current Status
In early 2022, responsibility for the Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) was transferred to The University of Minnesota and Bemidji State University. The information below is being preserved for historical reference, but is no longer current. For up-to-date information about the project, please contact Leslie Ludtke (ludtk028@umn.edu), Joe Magner (jmagner@umn.edu), or Miriam Rios-Sanchez (Miriam.Rios-Sanchez@bemidjistate.edu).
Historical Overview
The Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) brings together scientists from the U.S. Geological Survey, and students and professors from universities in Minnesota, North Dakota, Wisconsin, and California for a unique and cooperative study opportunity. This diverse group of scientists conducts research on physical, chemical, and biological processes of lakes, wetlands, and streams and investigates interfaces (air-water, air-land, land-water) on local and watershed scales. Scientists who might not normally work together learn from each other's approaches and develop new ideas for collaborative research. Each highly specialized study adds to a collective body of information that leads to a better understanding of the processes that occur in and adjacent to lakes, wetlands, and streams. By focusing on the interfaces of these multiple scientific disciplines, SHAEP hopes to provide a broader scientific perspective than could be achieved without such a cooperative integration. The Shingobee River Fact Sheet provides more detailed information about the site location and specific research goals.
Interdisciplinary research is not a new idea, but it was rarely accomplished in 1989 when this study began. The prospect was so novel that this effort initially was known as the Interdisciplinary Research Initiative, or IRI. IRI was changed to SHAEP to better reflect the site location and the overarching goals of the research conducted there.
Brief History of the Project
In 1987 a group of scientists from the former National Research Program of the Water Resources Division of the US Geological Survey met to discuss the state of watershed science. The committee agreed that proper management of our Nation's water resources required knowledge of how atmospheric water, surface water, and ground water function as integrated systems. It was obvious that an interdisciplinary approach to studying lakes and watersheds was needed. The committee decided to focus initially on lakes, because lakes are a natural integrator of hydrologic processes. Rather than focus these efforts on one lake, with the hope that the information learned about this lake would transfer to other lakes the committee decided to select a paired-lake site, where two nearby lakes would have greatly different water and chemical residence times. By studying two lakes, and comparing the results, they would be able to determine which processes were important to both lakes, and which were unique to one or the other lake.
A nationwide search resulted in the selection of the upper Shingobee River watershed located in north-central Minnesota. This watershed offered two lakes that had greatly different hydrologic settings even though they were close to each other. Several different types of wetlands offered a broad scope of wetlands research, and the headwaters of the Shingobee River presented a great opportunity for in-stream and riparian-corridor-scale research. Research to date has focused on Williams Lake and Shingobee Lake, as well as on processes occurring along the Shingobee River and within a nearby fen.
Shingobee Field Station
Dallas Hudson is the resident technician based at the Shingobee Field Station. Dallas collects hydrologic, atmospheric, biological and water-quality information that constitutes the data backbone of the SHAEP effort. Dallas is available to assist with project-specific data-collection efforts as time allows.
With the exception of Dallas, all who work at the SHAEP do so on a part-time and voluntary basis. Each has other duties and commitments, but all come to work at the Shingobee site to learn from colleagues with different perspectives, and make new discoveries about the SHAEP lakes and the land around them.
Amenities at the Shingobee Field Station include:
- Wireless access to internet
- Two bedrooms for visiting scientists
- Kitchen, laundry, storage
- Direct access to Shingobee Lake
- 3-season meeting room
- Boat available to those with USGS motorboat-safety training
- Assistance from Dallas Hudson can be arranged
Current Research
Current interdisciplinary research is focused on three main topics:
- Processes associated with the carbon budgets of the two lakes
- Physical, chemical and biological processes in the Little Shingobee Fen
- Physical, chemical and biological processes along the Shingobee River
Refinement of hydrologic budget for Shingobee Lake (Rosenberry, Hudson)
The "Great Wall of Shingobee" at the outlet to Shingobee Lake was working well to restrict and accelerate very slow flow at the outlet to allow us to make accurate measurements of stream discharge from Shingobee Lake. In spite of Dallas’s Herculean efforts to keep beaver dams at bay, the ever persistent critters built large dams well downstream, out of Dallas’s reach. Flow at the outlet slowed to the point where accurate discharge measurements were no longer possible. An extension of the great wall did the trick and we are back in business.
Temporal and spatial variability in discharge of springs (Rosenberry, Hudson)
Groundwater discharge to Shingobee Lake via numerous near-shore springs continues to vary over time in ways that are not always related to weather or lake stage. We are in the process of collecting water-quality samples from several of the springs in an effort to determine ages and flow paths for ground water discharging from the springs. A MODFLOW groundwater-flow model is in need of further refinement should someone be interested in joining this effort.
Source of carbon to Shingobee Lake (Striegl et al.) Gas-flux research (Dornblaser et al.)
Rob Striegl and Mark Dornblaser continue to home in on quantifying several of the carbon fluxes associated with Williams and Shingobee lakes. Manual and/or synoptic-scale measurements are needed to support data provided by gas-flux sensors installed on rafts deployed in Williams and Shingobee Lakes.
Lake sediment chemistry (Schuster et al.)
Paul Schuster and colleagues published a paper in 2003 in Hydrological Processes in which they characterized and contrasted the chemical characteristics of the shallow, near-shore sediments of Williams Lake in an area where ground water discharges to the lake, and another area where lake water flows to the groundwater system. That was then; this is well over a decade later. It would be very interesting to repeat this study to see what processes continue and what has changed with increasing open-water periods and evolving ecosystems.
Paleolimnology (in need of a new lead)
Several papers were published in 2003 related to the paleolimnology of the site. Walter Dean and colleagues discussed the effect of groundwater on accumulation of iron and manganese in the deep-lake sediments (Dean et al., 2003, Ground Water). Sheryl Filby and company modeled the hydrology of the site during the mid-Holocene (Filby et al., 2003, Quaternary Research). Antje Schwalb reported on lacustrine ostracodes related to climate dynamics during the Holocene (Schwalb, 2003, Journal of Paleolimnology). After that, emphasis shifted to Steel Lake, situated between Williams and Shingobee Lakes, where varved sediments presented a fantastic view into the post-glacial past (Nelson et al., 2004, Proceedings of the National Academy of Sciences; Nelson et al., 2007, Microbial Ecology; Nelson et al., 2008, New Phytologist; Tian et al, 2005, The Holocene; Tian et al., 2006, Geophysical Research Letters; Wright et al., 2005, Quaternary Science Reviews). Walt Dean and Lisa Doner then moved the focus to Little Shingobee Lake and adjacent fen, where sediment cores yielded pollen and geochemical evidence that the lake ecosystem was changing profoundly to a changing climate as the prairie-forest boundary transitioned past the site (Dean and Doner, 2012, Journal of Paleolimnology). Their results are directly relevant to what appears to be a rapidly changing climate at the site right now.
Glacial mapping (Melchior)
Bob Melchior completed his long-awaited USGS report on the glacial history of the Shingobee headwaters area (Melchior, 2014, USGS SIR). Melchior reports that a large glacial lake occupied nearly the entire Shingobee watershed until an ice-cored dam broke, creating a catastrophic flood that eroded the large valley through which the modern-day Shingobee River flows. Bob also discusses the creation of sub-glacial tunnel valleys and eskers just north of Shingobee Lake. The carving out of nearby Leech Lake along with the associated creation of large hills between Leech Lake and Shingobee Lake a “hill-hole pair,” is a new concept advanced by Bob. If this paper isn’t fascinating enough, a road log of the geology of northern Minnesota, including the Shingobee site, extends the glacial picture to well beyond the Shingobee headwaters area (Rosenberry et al., 2011, Geological Society of America Field Guide).
Survey of vegetation type related to hydrologic setting (Melchior)
Bob Melchior has shifted from geology to botany as he continues his research in the Shingobee headwaters area. Bob is always looking for field help should anyone care to assist with this effort.
Growth rate of northern pike in Shingobee Lake (Hudson, Carlson)
Imagine catching a 39-inch northern, wrestling it into the boat, recording the tag number, length, girth, weight, and then tossing it back in the water; and then catching another just like it later in the same day. This is an ichthyologists’ dream and this happens on a regular basis at Shingobee Lake. Some of these lunkers have been caught nearly 20 times. Little did we know that Dallas, in part due to these pursuits, is the most interesting man in Minnesota, but the proof is in a feature article in the Sunday Minneapolis Tribune (Tribune link from the NRP web pages here). Dallas Hudson keeps this study going in his spare time and Bruce Carlson, retired research scientist from the University of Michigan and current resident of nearby Ten Mile Lake, makes sense of the plethora of data produced by the 10,000 or so tagged northerns. Andy Hafs from Bemidji State and his graduate student, John Kempe, have recently joined the effort.
Phenology of the Shingobee headwaters area (Hudson)
Dallas Hudson records first sightings, numbers, last sightings, and several other phenological observations for several hundred species of mammals, insects, and flora. We are in need of someone to help make sense of all these valuable data that contain some very interesting trends. Dallas also has been the first observer of several species in Hubbard County, several of which have never been observed so far north.
Research of lakes, streams and wetlands in a small-watershed setting
Watershed-scale research has been a significant component of hydrologic and ecological disciplines for many decades, and small-watershed studies have been especially common and useful because of their scale. It is much easier to quantify processes, assess heterogeneities and extrapolations of results, and scale those results when studying a watershed that is relatively small. The Upper Shingobee watershed is only 28 square kilometers in area and much of the research is focused on subwatersheds within the Shingobee headwaters area. An overview of research highlights from studies conducted at Williams Lake, Shingobee Lake, the Shingobee River upstream of Shingobee Lake, and the Little Shingobee Fen, was presented at the First Interagency Conference on Research in the Watersheds during Fall 2003 (Rosenberry et al., 2003, Conference proceedings), and serves as a template for continuing ecosystems research opportunities at Shingobee.
Available Data from the Shingobee Site
Much data has been collected from the Shingobee site since its inception. Some data are collected only once or infrequently during synoptic studies for special research interests. However some data are collected during regular intervals and include:
- climate data
- water-chemistry data from Williams Lake, Shingobee Lake and the Shingobee River
- hydrology data
While some data have not yet been processed, checked for errors, or analyzed, many of these data are available upon request. Please contact Richard Webb (rmwebb@usgs.gov) with request for climate, water-chemistry or hydrology data.
- Publications
Selected USGS Publications from the Shingobee Headwaters Aquatic Ecosystems Project appear below. You can also download a complete bibliography for the project.
Watershed-scale research from many perspectives : the Interdisciplinary Research Initiative at the Shingobee River headwaters area, Minnesota
No abstract available.AuthorsD. O. RosenberryFilter Total Items: 54DIN retention-transport through four hydrologically connected zones in a headwater catchment of the Upper Mississippi River
Dissolved inorganic nitrogen (DIN) retention-transport through a headwater catchment was synthesized from studies encompassing four distinct hydrologic zones of the Shingobee River Headwaters near the origin of the Mississippi River. The hydrologic zones included: (1) hillslope ground water (ridge to bankside riparian); (2) alluvial riparian ground water; (3) ground water discharged through subchaAuthorsF.J. Triska, J.H. Duff, R.W. Sheibley, A. P. Jackman, R. J. AvanzinoHydrologic response of the Crow Wing Watershed, Minnesota, to mid-Holocene climate change
In this study, we have integrated a suite of Holocene paleoclimatic proxies with mathematical modeling in an attempt to obtain a comprehensive picture of how watersheds respond to past climate change. A three-dimensional surface-water-groundwater model was developed to assess the effects of mid-Holocene climate change on water resources within the Crow Wing Watershed, Upper Mississippi Basin in noAuthorsM. Person, P. Roy, H. Wright, W. Gutowski, E. Ito, T. Winter, D. Rosenberry, D. CohenComparison of local- to regional-scale estimates of ground-water recharge in Minnesota, USA
Regional ground-water recharge estimates for Minnesota were compared to estimates made on the basis of four local- and basin-scale methods. Three local-scale methods (unsaturated-zone water balance, water-table fluctuations (WTF) using three approaches, and age dating of ground water) yielded point estimates of recharge that represent spatial scales from about 1 to about 1000 m2. A fourth method (AuthorsG. N. Delin, R. W. Healy, D. L. Lorenz, J. R. NimmoEffect of humic substance photodegradation on bacterial growth and respiration in lake water
This study addresses how humic substance (HS) chemical composition and photoreactivity affect bacterial growth, respiration, and growth efficiency (BGE) in lake water. Aqueous solutions of HSs from diverse aquatic environments representing different dissolved organic matter sources (autochthonous and allochthonous) were exposed to artificial solar UV radiation. These solutions were added to lake wAuthorsA.M. Anesio, W. Graneli, G. R. Aiken, D.J. Kieber, K. MopperComparison of wetlands in different hydrogeological settings under conditions of extreme climate variability
Wetlands in the Cottonwood Lake area in North Dakota, USA, are underlain by poorly permeable till and have little groundwater input. Lakes and wetlands in the Shingobee River headwaters in Minnesota are underlain by permeable sand and have substantial groundwater input. Hydrological, chemical, and biological characteristics of these ecosystems have been monitored since 1977. Both sites experiencedAuthorsT. Winter, D. Rosenberry, E. Kelly, J. LaBaughIntegrating seepage heterogeneity with the use of ganged seepage meters
The usefulness of standard half-barrel seepage meters for measurement of fluxes between groundwater, and surface water is limited by the small bed area that each measurement represents and the relatively large associated labor costs. Standard half-barrel cylinders were ganged together to allow one measurement of the summed seepage through all of the meters, reducing labor cost and increasing the rAuthorsD. O. RosenberryComparison of 13 equations for determining evapotranspiration from a prairie wetland, Cottonwood Lake Area, North Dakota, USA
Evapotranspiration determined using the energy-budget method at a semi-permanent prairie-pothole wetland in east-central North Dakota, USA was compared with 12 other commonly used methods. The Priestley-Taylor and deBruin-Keijman methods compared best with the energy-budget values; mean differences were less than 0.1 mm d−1, and standard deviations were less than 0.3 mm d−1. Both methods require mAuthorsDonald O. Rosenberry, David L. Stannard, Thomas C. Winter, Margo L. MartinezCharacterization of lake water and ground water movement in the littoral zone of Williams Lake, a closed-basin lake in North central Minnesota
Williams Lake, Minnesota is a closed‐basin lake that is a flow‐through system with respect to ground water. Ground‐water input represents half of the annual water input and most of the chemical input to the lake. Chemical budgets indicate that the lake is a sink for calcium, yet surficial sediments contain little calcium carbonate. Sediment pore‐water samplers (peepers) were used to characterize sAuthorsP. F. Schuster, M.M. Reddy, J. W. LaBaugh, R.S. Parkhurst, D. O. Rosenberry, T. C. Winter, Ronald C. Antweiler, W.E. DeanInorganic nitrogen transformations in the bed of the Shingobee River, Minnesota: Integrating hydrologic and biological processes using sediment perfusion cores
Inorganic N transformations were examined in streambed sediments from the Shingobee River using sediment perfusion cores. The experimental design simulated groundwater-stream water mixing within sediment cores, which provided a well-defined one-dimensional representation of in situ hydrologic conditions. Two distinct hydrologic and chemical settings were preserved in the sediment cores: the lowermAuthorsR.W. Sheibley, J.H. Duff, A. P. Jackman, F.J. TriskaThe lacustrine carbon cycle as illuminated by the waters and sediments of two hydrologically distinct headwater lakes in north-central Minnesota, U.S.A
The accumulation rates of CaCO3 and organic carbon (OC) in lake sediments are delicately balanced between production in the epilimnion and destruction in the hypolimnion. The cycling of these two forms of carbon makes a "carbon pump" that greatly affects the biogeochemical cycles of other elements. To further understand these biogeochemical dynamics, the lakes, streams, and wetlands of the ShingobAuthorsWalter E. Dean, Antje SchwalbReconstruction of hydrological changes and response to effective moisture variations from North-Central USA lake sediments
Ratios of the stable isotopes of oxygen and carbon in benthic ostracodes and marl from cores taken from two lakes in north-central Minnesota reflect Holocene hydrological and vegetation changes. Oxygen isotopes show that Williams and Shingobee Lakes, located in the same watershed but with different positions along a hydrologic gradient, were connected before 9.8 ka as part of a larger lake, Lake WAuthorsA. Schwalb, W.E. DeanMid-Holocene hydrologic model of the Shingobee watershed, Minnesota
A hydrologifc model of the Shingobee Watershed in north-central Minnesota was developed to reconstruct mid-Holocene paleo-lake levels for Williams Lake, a surface-water body located in the southern portion of the watershed. Hydrologic parameters for the model were first estimated in a calibration exercise using a 9-yr historical record (1990-1998) of climatic and hydrologic stresses. The model repAuthorsS.K. Filby, Sharon M. Locke, M.A. Person, T. C. Winter, D. O. Rosenberry, J.L. Nieber, W.J. Gutowski, E. Ito