Physical Sciences and Mathematics Commons^™

Oxygen Budget For Lake Ogallala, Kyle D. Hoagland, John C. Holz, Tadd M. Barrow, Richard J. Ruane

School of Natural Resources: Faculty Publications

Lake Ogallala, located below Kingsley Dam which impounds Lake McConaughy in Keith County, Nebraska, is a 260-surface hectare lake with an average depth of approximately eight meters. The lake provides mUltiple uses including a sport fishery and a hydropower and irrigation regulation basin. Since the installation of the hydroelectric generating plant in 1984 (Kingsley Dam was constructed in 1942) and the continued eutrophication of Lake McConaughy, dissolved oxygen concentrations have generally declined in Lake Ogallala. Hypolimnetic withdrawal from Lake McConaughy results in depressed oxygen levels in Lake Ogallala during the mid to latter part of the summer, particularly in certain …

Late Albian Kiowa-Skull Creek Marine Transgression, Lower Dakota Formation, Eastern Margin Of Western Interior Seaway, R.L. Brenner, G.A. Ludvigson, B.J. Witzke, A.N. Zawistoski, E.P. Kvale, R.L. Ravn, R.M. Joeckel

School of Natural Resources: Faculty Publications

No abstract provided.

Potential Production And Environmental Effects Of Switchgrass And Traditional Crops Under Current And Greenhouse-Altered Climate In The Central United States: A Simulation Study, R.A. Brown, N.J. Rosenberg, Cynthia J. Hays, W.E. Easterling, L.O. Mearns

School of Natural Resources: Faculty Publications

If, as many climate change analysts _ speculate, industrial and other emissions of CO₂ can be offset by substitution of biofuels, large areas of land, including agricultural land, may be converted to the production of biomass feedstocks. This paper explores the feasibility for the Missouri–Iowa–Nebraska–Kansas (MINK) region of the US of converting some agricultural land to the production of switchgrass (Panicum virgatum L.), a perennial warm season grass, as a biomass energy crop. The erosion productivity impact calculator (EPIC) crop growth model simulated production of corn (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench), soybean ( …

Observed Climate Variability And Change Of Relevance To The Biosphere, David R. Easterling, Thomas R. Karl, Kevin P. Gallo, David A. Robinson, Kevin E. Trenberth, Aiguo Dai

School of Natural Resources: Faculty Publications

In this paper we review the current instrumental evidence regarding climate variations and change during the 20th century emphasizing those changes that are likely to have direct interactions with the biosphere.

The Spectral Contribution Of Carotenoids To Light Absorption And Reflectance In Green Leaves, Y. Zur, A. A. Gitelson, O. B. Chivkunova, M. N. Merzlyak

School of Natural Resources: Faculty Publications

Absorbance and reflectance spectra in the visible and near infrared range of the spectrum, acquired for maple (Acer platanoides L.) leaves were studied. Standard deviation of absorbance spectra showed that in yellow to green leaves, with chlorophyll content at least up to 30 nmol/cm2, there is a spectral feature at 520 nm attributable to carotenoids. Reflectance around 520 nm also correlates closely with carotenoids content in yellow to green leaves. Thus, this spectral feature at 520 nm could be used as a measure of carotenoids content in green leaves and plants.

Breeding Season Demography And Movements Of Eastern Towhees At The Savannah River Site, South Carolina, David G. Krementz, Larkin A. Powell

School of Natural Resources: Faculty Publications

The Eastern Towhee (Pipilo erythrophthalmus) has undergone population declines across much of its range, especially in New England. Despite being a widespread and, at one time, a common species, relatively little is known about its natural history, ecology, or demographics. We conducted baseline research on Eastern Towhees at the Savannah River Site, South Carolina, in 1995 and 1996 to estimate breeding season survival rates, nest success rates, breeding densities, and daily movements. We also were interested in whether towhees had differences in survival and movement rates between young and mature managed pine stands. We found that survival rates during the …

Effects Of Temperature Anomalies On The Palmer Drought Severity Index In The Central United States, Q. Steven Hu, Gary D. Willson

School of Natural Resources: Faculty Publications

The purpose of this study is to improve our understanding of temperature and precipitation effects on the Palmer Drought Severity Index (PDSI). Both theoretical and observational analyses were applied to separate and compare temperature and precipitation effects on PDSI. The results showed that because of the dependence of PDSI on the ‘climatologically appropriate rainfall’, which is a function of time and varies with surface air temperature, the PDSI can be equally affected by temperature and precipitation, when both have similar magnitudes of anomalies. Calculations using observational data further illustrated the temperature influence on PDSI in different climate regions in the …

Remote Monitoring Of Selected Ground-Water Dominated Lakes In The Nebraska Sand Hills, David C. Gosselin, Donald C. Rundquist, Stuart K. Mcfeeters

School of Natural Resources: Faculty Publications

The Landsat-Multispectral Scanner (MSS) data were used to measure lake area fluctuations (1972-1989) for 130 groundwater dominated lakes in the Western Lakes Region of the Nebraska Sand Hills. In general, the pattern shown in lake area hydrographs was similar to that for in-situ lake elevations. In-situ lake-elevation data verify that remote monitoring of surface- area fluctuations, even at relatively coarse spatial resolution, is not only practical and useful, but also it elucidates the hydrologic characteristics of groundwater-dominated lakes of the Sand Hills. The apparent differences in behavior between lakes in the northern and southern portions of the study area may …

Process-Oriented Environmental Change Curriculum-Development Workshops, David C. Gosselin, Sherri Lowrey, Steven John Meyer

School of Natural Resources: Faculty Publications

To improve scientific literacy, K-12 educators need to: develop the ability to use and analyze data, incorporate data into their curriculum, and interact with teachers from other disciplines to create interdisciplinary units. A Process-Oriented Environmental Change Education workshop was conducted for eleven interdisciplinary teams, consisting of 21 teachers, in 1997 and 1998. The National Science Standards provided the criteria for the organization of the workshop. Inquiry and interpretation exercises helped to expand scientific knowledge and skills as well as the teachers’ use of technology. We explicitly discussed the uncertainty of science through group discussions and problem-solving activities. More than 85% …

The Effect Of Structure On The Drag Force Of A Windbreak, James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Geochemical Evidence For An Eolian Sand Dam Across The North And South Platte Rivers In Nebraska, Daniel R. Muhs, James B. Swinehart, David B. Loope, Josh Been, Shannon A. Mahan, Charles A. Bush

School of Natural Resources: Faculty Publications

Geochemical and geomorphic data from dune fields in southwestern Nebraska provide new evidence that the Nebraska Sand Hills once migrated across the North and South Platte rivers and dammed the largest tributary system to the Missouri River. The Lincoln County and Imperial dune fields, which lie downwind of the South Platte River, have compositions intermediate between the Nebraska Sand Hills (quartz-rich) and northeastern Colorado dunes (K-feldspar-rich). The most likely explanation for the intermediate composition is that the Lincoln County and Imperial dunes are derived in part from the Nebraska Sand Hills and in part from the South Platte River. The …

Reconnaissance Survey Of Lewis And Clark On The Missouri National Recreational River, Nebraska And South Dakota, Anne P. Diffendal, Gary E. Moulton, Michael Shambaugh-Miller, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Part I
Lewis and Clark on the Middle Missouri by Gary E. Moulton
Appendix: Principal Sites and Events
Select Bibliography

Part II
Locating Lewis and Clark Sites
Site #1 Floyd's Bluff
Site #2 Gass's Election
Site #3 Ionia Volcano
Site #4 1804 Mouth of the Vermillion River
Site #5 Spirit Mound
Site #6 Shannon's Absence
Site #7 Calumet Bluff
Site #8 "Ancient Fortifications"
Site #9 Mouth of the Niobrara River
Site # 10 Old Baldy

Earth In Four Dimensions: Development Of The Ideas Of Geologic Time And History, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Changes in ideas and in technology can come about as slow incremental modifications, as well as by major paradigm shifts. In the case of the development of the ideas of geologic history and time, I will try to present these changes broadly and then look at how some of these have affected interpretation of Nebraska geology. Changes of view on three fronts were important in the development of geologic history and time concepts. First is the question of the nature of time. Is time cyclic or is it linear? The Greco-Oriental cultures had a world view based on cosmic cycles, …

Notes And Correspondence: The Effects Of Data Gaps On The Calculated Monthly Mean Maximum And Minimum Temperatures In The Continental United States: A Spatial And Temporal Study, David E. Stooksbury, Craig D. Idso, Kenneth G. Hubbard

School of Natural Resources: Faculty Publications

Gaps in otherwise regularly scheduled observations are often referred to as missing data. This paper explores the spatial and temporal impacts that data gaps in the recorded daily maximum and minimum temperatures have on the calculated monthly mean maximum and minimum temperatures. For this analysis 138 climate stations from the United States Historical Climatology Network Daily Temperature and Precipitation Data set were selected. The selected stations had no missing maximum or minimum temperature values during the period 1951–80. The monthly mean maximum and minimum temperatures were calculated for each station for each month. For each month 1–10 consecutive days of …

Filter Strip Performance And Processes For Different Vegetation, Widths, And Contaminants, T. J. Schmitt, M. G. Dosskey, K. D. Hoagland

School of Natural Resources: Faculty Publications

Filter strips are widely prescribed to reduce contaminants in surface runoff from agricultural fields. Tbis study compared performance of different filter strip designs on several contaminants and evaluated the contribnting processes. Different vegetation types and widths were investigated using simulated runoff event on large plots (3 m X 7.5 or 15 m) having fine-textured soil and a 6 to 7% slope. Filter strips 7.5 and 15 m wide downslope greatly reduced concentrations of sediment in runoff (76-93%) and contaminants strongly associated with sediment (total P, 55-79%; permethrin, 27-83% [(3-phenoxyphenyl) methyl (±)-cis, trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane carboxylate ]). They had less effect on concentrations …

An Objective Method For Determining Principal Time Scales Of Coherent Eddy Structures Using Orthonormal Wavelets, Jozsef Szilagyi, Marc B. Parlange, Gabriel G. Katul, John D. Albertson

School of Natural Resources: Faculty Publications

No abstract provided.

Streamflow Depletion Investigations In The Republican River Basin: Colorado, Nebraska, And Kansas, Jozsef Szilagyi

School of Natural Resources: Faculty Publications

No abstract provided.

Global Rural Temperature Trends, Thomas C. Peterson, Kevin P. Gallo, Jay Lawrimore, Timothy W. Owen, Alex Huang, David A. Mckittrick

School of Natural Resources: Faculty Publications

Using rural/urban land surface classifications derived from maps and satellite observed nighttime surface lights, global mean land surface air temperature time series were created using data from all weather observing stations in a global temperature data base and from rural stations only. The global rural temperature time series and trends are very similar to those derived from the full data set. Therefore, the well-known global temperature time series from in situ stations is not significantly impacted by urban warming.

Satellite-Based Adjustments For The Urban Heat Island Temperature Bias, Kevin P. Gallo, Timothy W. Owen

School of Natural Resources: Faculty Publications

Monthly and seasonal relationships between urban–rural differences in minimum, maximum, and average temperatures measured at surface-based observation stations were compared to satellite-derived Advanced Very High Resolution Radiometer estimates of a normalized difference vegetation index (NDVI) and surface radiant temperature.

A Revised Measurement Methodology For Conifer Needles Spectral Optical Properties: Evaluating The Influence Of Gaps Between Elements, Mark A. Mesarch, Elizabeth Walter-Shea, Gregory P. Asner, Elizabeth M. Middleton, Stephen Chan

School of Natural Resources: Faculty Publications

Gaps are unavoidable when compositing small or narrow plant parts (e.g., conifer needles, twigs, narrow leaves, and leaflets) on sample holders in preparation for measuring spectral optical properties. The Daughtry et al. (1989) (A new technique to measure the spectral properties of conifer needles. Remote Sens. Environ. 27:81-91.) method of measuring conifer needle optical properties utilizes a relatively large gap fraction (approximately 0.3-0.6) and needles painted black on one surface of the sample from which the gap fraction of the sample is indirectly determined. Following this protocol typically results in distortions in optical properties, including underestimates in transmittance (sometimes negative …

The Relative Importance Of Patch Area And Perimeter–Area Ratio To Grassland Breeding Birds, Christopher J. Helzer, Dennis E. Jelinski

School of Natural Resources: Faculty Publications

Habitat fragmentation has been implicated as a major cause of population decline in grassland birds. We tested the hypothesis that a combination of area and shape determines the use of grassland patches by breeding birds. We compared both species richness and individual species presence in 45 wet meadow grasslands in the floodplain of the central Platte River, Nebraska. Bird data were collected through the use of belt transects and supplemented by walking and listening outside transects. Our data supported our primary hypothesis that perimeter–area ratio, which reflects both the area and shape of a patch, is the strongest predictor of …

Iron-Mediated Remediation Of Rdx-Contaminated Water And Soil Under Controlled Eh/Ph, J. Singh, Steven Comfort, Patrick Shea

School of Natural Resources: Faculty Publications

Soil and water contaminated with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a serious environmental problem at several active and abandoned munitions production facilities. Zero-valent iron (Fe⁰) can effectively remediate RDX-contaminated soil and water. The objective of this study was to manipulate Eh and pH for enhanced Fe⁰-mediated destruction of RDX. This was accomplished by monitoring RDX destruction under controlled Eh-pH conditions (Eh: −300 to +150 mV; pH: 2−10). Decreasing Eh and pH increased RDX destruction in aqueous solution. Treating 20 mg of RDX L-1 (90 μM) under a static Eh of −150 mV and pH 7 with 20 g …

Geology Of Rock Creek Station State Historical Park, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Contents

Location and Facilities
Geology of the Park
Valley Floor of Rock Creek
While You Are in the Area

Temperature Trends Of The U.S. Historical Climatology Network Based On Satellite-Designated Land Use/Land Cover, Kevin P. Gallo, Timothy W. Owen, David R. Easterling, Paul F. Jamason

School of Natural Resources: Faculty Publications

The 1221 weather observation stations that compose the U.S. Historical Climatology Network were designated as either urban, suburban, or rural based on data from the Defense Meteorological Satellite Program Operational Linescan System (OLS).

Form, Function, And Evolution In Skulls And Teeth Of Bats, Patricia W. Freeman

School of Natural Resources: Faculty Publications

Bats provide a model system for tracking change from the primitive mammalian tooth pattern to patterns indicating the more-derived food habits of carnivory, nectarivory, frugivory, and sanguinivory. Whereas microchiropteran bats show all these transitions, megachiropterans illustrate an alternative pattern concerned only with frugivory and nectarivory. In microchiropterans, it is likely that carnivory nectarivory, frugivory, and sanguinivory are all derived from a dilambdodont insectivorous tooth pattern. Megachiropterans are troublesome because they appear as nectarivores or frugivores without a clear relationship to ancestral taxa.

The nature of the food item and how teeth respond to that item evolutionarily is an issue I …

Amphibians And Reptiles [Of The Sand Hills], Patricia W. Freeman

School of Natural Resources: Faculty Publications

Of the 60 species of amphibians and reptiles presently known from Nebraska, 27 are found in the Sand Hills and one more is marginal to the east. Fourteen species of the 60 are essentially state wide in distribution, including the Sand Hills, and eight species of reptiles are strongly influenced by the Sand Hills (Lynch, 1985). Of 12 species that occur widely over the moister eastern part of the state, only four extend into the Sand Hills, and one occurs only under the wet conditions along the rivers of the eastern Sand Hills.

Amphibians: Tiger salamander (Ambystoma tigrinum); …

Mammals [Of The Sand Hills], Patricia W. Freeman

School of Natural Resources: Faculty Publications

Of approximately 81 species of mammals present in Nebraska today, 55 occur in the Sand Hills, with an additional three species that are associated only with the Niobrara River. Nebraska as a whole is truly a crossroads for mammals because two-thirds of the species reach their distributional limits in the state (Jones, 1964). Most of these mammals are widespread species or are specific to the grasslands as a whole and are not affected by this sandy zone. Jones (1964) wrote that “only a few mammals are restricted to this area. Mostly it serves to filter western species moving east and, …

Relationship Between Ecosystem Productivity And Photosynthetically Active Radiation For Northern Peatlands, S. E. Frolkin, J.L. Bubier, T.R. Moore, T. Ball, L.M. Bellisario, A. Bhardwaj, P. Carroll, P.M. Crill, Peter M. Lafleur, J.H. Mccaughey, N.T. Roulet, A. E. Suyker, S.B. Verma, J.M. Waddington, G.J. Whiting

School of Natural Resources: Faculty Publications

We analyzed the relationship between new ecosystem exchange of carbon dioxide (NEE) and irradiance (as photosynthetic photon flux density of PPFD), using published and unpublished data that have been collected during midgrowing season for carbon balance studies at seven peatlands in North America and Europe. NEE measurements included both eddy-correlation tower and clear, static chamber methods, which gave very similar results. Data were analyzed by site, as aggregated data set for all peatland type (bog, poor fen, rich fen, and all fens) and as a single aggregated data set for all peatlands. In all cases, a fit with a rectangular …

Air Temperature Variations And Rice Productivity In Bangladesh: A Comparative Study Of The Performance Of The Yield And The Ceres-Rice Models, Rezaul Mahmood

School of Natural Resources: Faculty Publications

Potential increase in air temperature due to climatic change and inter-annual climatic variability and its impacts on crop productivity is of major concern to crop scientists. A number of physically-based models have been developed and applied to estimate crop–environment relationships. In the present study the performance of two such models (the YIELD and the CERES-Rice) are discussed. These two models are used to estimate boro rice productivity under normal and abnormal climate scenarios in Bangladesh. This study finds that boro rice productivity at Mymensingh predicted by the YIELD is higher than the prediction by the CERES-Rice. Productivity estimates for Barisal …

Climatology Of The Daily Temperature Range Annual Cycle In The United States, Daniel J. Leathers, Michael A. Palecki, David A. Robinson, Kenneth F. Dewey

School of Natural Resources: Faculty Publications

Many researchers are presently interested in detecting long-term trends in annual or seasonal daily temperature range (DTR), and attributing these changes to anthropogenic origins. However, very little work has been done to confirm the mechanisms that are important to determining the long-term average annual cycle of the DTR. Therefore, the focus of this work is to examine the spatial and temporal difference in the DTR average annual cycle across the United States, and to associate the patterns of these cycles with potential causal variables. Three major types of DTR annual cycle exist in the United States: high sun season maximum …