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Articles 151 - 177 of 177
Full-Text Articles in Environmental Monitoring
Environmental Controls On The Landscape-Scale Biogeography Of Stream Bacterial Communities, Noah Fierer, Jennifer L. Morse, Sean T. Berthrong, Emily S. Bernhardt, Robert B. Jackson
Environmental Controls On The Landscape-Scale Biogeography Of Stream Bacterial Communities, Noah Fierer, Jennifer L. Morse, Sean T. Berthrong, Emily S. Bernhardt, Robert B. Jackson
Environmental Science and Management Faculty Publications and Presentations
We determined the biogeographical distributions of stream bacteria and the biogeochemical factors that best explained heterogeneity for 23 locations within the Hubbard Brook watershed, a 3000-ha forested watershed in New Hampshire, USA. Our goal was to assess the factor, or set of factors, responsible for generating the biogeographical patterns exhibited by microorganisms at the landscape scale. We used DNA fingerprinting to characterize bacteria inhabiting fine benthic organic matter (FBOM) because of their important influence on stream nutrient dynamics. Across the watershed, streams of similar pH had similar FBOM bacterial communities. Streamwater pH was the single variable most strongly correlated with …
Middle Columbia River Aquatic Nuisance Species Survey, Robyn Draheim, Mark D. Sytsma, Rich Miller, Jeffery Cordell
Middle Columbia River Aquatic Nuisance Species Survey, Robyn Draheim, Mark D. Sytsma, Rich Miller, Jeffery Cordell
Center for Lakes and Reservoirs Publications and Presentations
Aquatic nonindigenous species (ANS) in the middle Columbia and lower Snake rivers were surveyed during the summer of 2006. The project area included eight reservoirs and the free-flowing, Hanford Reach on the Columbia River. We also conducted a literature review to create a complete list of ANS for the study area.
2005 Diamond Lake Submersed Aquatic Vegetation Survey, Mark D. Sytsma, Mary Pfauth
2005 Diamond Lake Submersed Aquatic Vegetation Survey, Mark D. Sytsma, Mary Pfauth
Center for Lakes and Reservoirs Publications and Presentations
Diamond Lake is a large natural lake having a surface area of some 3214 acres (1300.7 hectares) and a maximum depth of 52 feet (15.8 meters). It is located within the Umpqua National Forest in the Southern Cascade Mountains of Oregon, at an elevation of over 5000 feet (>1524 meters). Diamond Lake is a high-use waterbody that supports angling, public campgrounds, recreational boating, swimming, and water skiing. The human activity associated with the lake has been a significant contributor to the economy of southern Oregon since the early part of the twentieth century.
Historically Diamond Lake was fishless but …
Response Of Sagebrush Steppe Species To Elevated Co2 And Soil Temperature, Melissa S. Lucash, Blake Farnsworth, William E. Winner
Response Of Sagebrush Steppe Species To Elevated Co2 And Soil Temperature, Melissa S. Lucash, Blake Farnsworth, William E. Winner
Environmental Science and Management Faculty Publications and Presentations
Elevated atmospheric CO2 may cause long-term changes in the productivity and species composition of the sagebrush steppe. Few studies, however, have evaluated the effects of increased CO2 on growth and physiology of species important to this ecosystem. Since the response of plants to elevated CO2 may be limited by environmental factors, soil temperature was also examined to determine if low soil temperatures limit CO2 response. To determine how CO2 and soil temperature affect the growth of species native to the sagebrush steppe, bottlebrush squirreltail [Elymus elymoides (Raf.) Swezey], Thurber needlegrass (Stipa thurberiana Piper), …
Sediment Nutrient Accumulation And Nutrient Availability In Two Tidal Freshwater Marshes Along The Mattaponi River, Virginia, Usa, Jennifer L. Morse, J. Patrick Megonigal, Mark R. Walbridge
Sediment Nutrient Accumulation And Nutrient Availability In Two Tidal Freshwater Marshes Along The Mattaponi River, Virginia, Usa, Jennifer L. Morse, J. Patrick Megonigal, Mark R. Walbridge
Environmental Science and Management Faculty Publications and Presentations
Sediment deposition is the main mechanism of nutrient delivery to tidal freshwater marshes (TFMs). We quantified sediment nutrient accumulation in TFMs upstream and downstream of a proposed water withdrawal project on the Mattaponi River, Virginia. Our goal was to assess nutrient availability by comparing relative rates of carbon (C), nitrogen (N), and phosphorus (P) accumulated in sediments with the C, N, and P stoichiometries of surface soils and above ground plant tissues. Surface soil nutrient contents (0.60–0.92% N and 0.09–0.13% P) were low but within reported ranges for TFMs in the eastern US. In both marshes, soil nutrient pools and …
Relationships Between Needle Nitrogen Concentration And Photosynthetic Responses Of Douglas-Fir Seedlings To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey
Relationships Between Needle Nitrogen Concentration And Photosynthetic Responses Of Douglas-Fir Seedlings To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey
Environmental Science and Management Faculty Publications and Presentations
- Here we examined correlations between needle nitrogen concentration ([N]) and photosynthetic responses of Douglas-fir (Pseudotsuga menziesii) seedlings to growth in elevated temperatures and atmospheric carbon dioxide concentrations ([CO2]).
- Seedlings were grown in sunlit, climate-controlled chambers at ambient or ambient+3.5° C and ambient or ambient +180 μmol mol-1 CO2 in a full factorial design. Photosynthetic parameters and needle [N] were measured six times over a 21-month period.
- Needle [N] varied seasonally, and accounted for 30–50% of the variation in photosynthetic parameters. Across measurement periods, elevated temperature increased needle [N] by 26% and light-saturated …
Stomatal Responses Of Douglas-Fir Seedlings To Elevated Carbon Dioxide And Temperature During The Third And Fourth Years Of Exposure, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey
Stomatal Responses Of Douglas-Fir Seedlings To Elevated Carbon Dioxide And Temperature During The Third And Fourth Years Of Exposure, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey
Environmental Science and Management Faculty Publications and Presentations
Two major components of climate change, increasing atmospheric [CO2] and increasing temperature, may substantially alter the effects of water availability to plants through effects on the rate of water loss from leaves. We examined the interactive effects of elevated [CO2] and temperature on seasonal patterns of stomatal conductance (gs), transpiration (E) and instantaneous transpiration efficiency (ITE) in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings. Seedlings were grown in sunlit chambers at either ambient CO2 (AC) or ambient + 180 µmol mol-1 CO2 (EC), and at ambient temperature (AT) or ambient + 3.5° …
Reconnaissance Of Pharmaceutical Chemicals In Urban Streams Of The Tualatin River Basin, Oregon, 2002, Stewart A. Rounds, Micelis C. Doyle, Patrick M. Edwards, Edward T. Furlong
Reconnaissance Of Pharmaceutical Chemicals In Urban Streams Of The Tualatin River Basin, Oregon, 2002, Stewart A. Rounds, Micelis C. Doyle, Patrick M. Edwards, Edward T. Furlong
Environmental Science and Management Faculty Publications and Presentations
A reconnaissance of pharmaceutical chemicals in urban streams of the Tualatin River basin was conducted in July 2002 in an effort to better understand the occurrence and distribution of such compounds, and to determine whether they might be useful indicators of human-related stream contamination. Of the 21 pharmaceutical chemicals and metabolites tested, only 6 (acetaminophen, caffeine, carbamazepine, codeine, cotinine, and sulfamethoxazole) were detected in filtered stream samples from 10 sites. The concentrations of most of the detected compounds were relatively low (less than 0.05 microgram per liter). The most frequently detected compounds were cotinine (a nicotine metabolite, 8 of 10 …
Seasonal Patterns Of Photosynthesis In Douglas Fir Seedlings During The Third And Fourth Year Of Exposure To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey
Seasonal Patterns Of Photosynthesis In Douglas Fir Seedlings During The Third And Fourth Year Of Exposure To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey
Environmental Science and Management Faculty Publications and Presentations
The interactive effects of elevated atmospheric CO2 and temperature on seasonal patterns of photosynthesis in Douglas fir (Psuedotsuga menziesii (Mirb.) Franco) seedlings were examined. Seedlings were grown in sunlit chambers controlled to track either ambient (~400 p.p.m.) CO2 or ambient +200 p.p.m. CO2, and either ambient temperature or ambient +4 °C. Light-saturated net photosynthetic rates were measured approximately monthly over a 21 month period. Elevated CO2 increased net photosynthetic rates by an average of 21% across temperature treatments during both the 1996 hydrologic year, the third year of exposure, and the 1997 hydrologic year. Elevated …
Measurement Of Free Radicals Oh And Ho₂ In Los Angeles Smog, Linda Acha George, Thomas M. Hard, Robert J. O'Brien
Measurement Of Free Radicals Oh And Ho₂ In Los Angeles Smog, Linda Acha George, Thomas M. Hard, Robert J. O'Brien
Environmental Science and Management Faculty Publications and Presentations
Atmospheric free radicals hydroxyl and hydroperoxyl (OH and HO₂, collectively HOᵪ ) are the catalysts that cause secondary or photochemical air pollution. Chemical mechanisms for oxidant and acid formation, on which expensive air pollution control strategies are based, must accurately predict these radical concentrations. We have used the fluorescence assay with gas expansion (FAGE) technique to carry out the first simultaneous, in situ measurements of these two radicals in highly polluted air during the Los Angeles Free Radical Experiment. A complete suite of ancillary measurements was also made, including speciated hydrocarbons, carbon monoxide, aldehydes, nitric oxide, nitrogen dioxide, and ozone …
Internal Temperature Of Douglas-Fir Buds Is Altered At Elevated Temperature, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey, Donald L. Phillips
Internal Temperature Of Douglas-Fir Buds Is Altered At Elevated Temperature, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey, Donald L. Phillips
Environmental Science and Management Faculty Publications and Presentations
Pseudotsuga menziesii (Douglas-fir) saplings were grown in sun-lit controlled environment chambers at ambient or elevated (4°C above ambient) temperature. We measured internal temperatures of vegetative buds with thermocouple probes and compared temperatures of normal buds and abnormal buds with loosened, rosetted outer scales in elevated temperature chambers. The abnormal buds had higher and earlier peak daily temperatures than normal buds. Elevated temperature may influence the internal temperature of buds and contribute to the development of abnormal, rosetted buds with loosened outer scales. Abnormal bud development may alter branching patterns and allometry of Douglas-fir trees subjected to climatic change.
The Effects Of Urbanization And Human Disturbance Upon Plant Community Structure And Bird Species Richness, Diversity, And Abundance In A Natural Forested Area (Forest Park) In Portland, Oregon, Nancy Ellen Broshot
Dissertations and Theses
The effects of urbanization and continual human disturbance on the plant and avian communities of Forest Park and forested lands surrounding Portland, Oregon, were studied. I examined characteristics of plant and avian communities at 25 sites, 24 which were in Forest Park and surrounding areas and one which was in the Ancient Forest Preserve (old-growth stand) northwest of Forest Park. Data were analyzed using multiple regression, ANOV A, and Bonferonni/Dunn. Seven variables were selected representing different urbanization gradients. An additional covariable coded for the old-growth stand, allowing it to be used as a control.
Many tree variables, especially those related …
Morphogenesis Of Douglas Fir Buds Is Altered At Elevated Temperature But Not At Elevated Co2, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey
Morphogenesis Of Douglas Fir Buds Is Altered At Elevated Temperature But Not At Elevated Co2, Martha E. Apple, Melissa S. Lucash, David M. Olszyk, David T. Tingey
Environmental Science and Management Faculty Publications and Presentations
Global climatic change as expressed by increased CO2 and temperature has the potential for dramatic effects on trees. To determine what its effects may be on Pacific Northwest forests, Douglas-fir (Pseudotsuga menziesii ) seedlings were grown in sun-lit controlled environment chambers at ambient or elevated (+4°C above ambient) temperature, and at ambient or elevated (+200 ppm above ambient) CO2. In 1995–1996 and 1996–1997, elevated CO2 had no effect on vegetative bud morphology, while the following unusual morphological characteristics were found with greater frequency at elevated temperature than at ambient: rosetted buds with reflexed and loosened outer …
A Strategy For Monitoring Glaciers, Andrew G. Fountain, Robert M. Krimmel, Dennis C. Trabant
A Strategy For Monitoring Glaciers, Andrew G. Fountain, Robert M. Krimmel, Dennis C. Trabant
Geography Faculty Publications and Presentations
Glaciers are important features in the hydrologic cycle and affect the volume, variability, and water quality of runoff. Assessing and predicting the effect of glaciers on water resources require a monitoring program to provide basic data for this understanding. The monitoring program of the U.S. Geological Survey employs a nested approach whereby an intensively studied glacier is surrounded by less intensively studied glaciers and those monitored solely by remote sensing. Ideally, each glacierized region of the United States would have such a network of glaciers. The intensively studied glacier provides a detailed understanding of the physical processes and their temporal …
Captive Environmental Influences On Behavior In Zoo Drills And Mandrills (Mandrillus), A Threatened Genus Of Primate, Erik Terdal
Captive Environmental Influences On Behavior In Zoo Drills And Mandrills (Mandrillus), A Threatened Genus Of Primate, Erik Terdal
Dissertations and Theses
Drills (Mandrillus leucophaeus) are an endangered species of African monkey (Cercopithecidae), and their sole congener the mandrill (Mandrillus sphinx) is vulnerable to extinction. Both species are threatened in the wild by deforestation and hunting.
Drills have a poor record of captive reproduction. Many individuals appear to have behavioral deficiencies which interfere with reproduction. Thus, the zoo population of drills does not serve as a “hedge” against the species’ total extinction: drills are endangered in captivity as well as in the wild. Mandrills, by contrast, reproduce well in captivity. Information on the behavior of mandrills in captivity may help zoo managers …
Intercomparison Of Local Hydroxyl Measurements By Radiocarbon And Fage Techniques, Malcolm J. Campbell, Brad D. Hall, John C. Sheppard, Philip L. Utley, Robert J. O'Brien, Thomas M. Hard, Linda Acha George
Intercomparison Of Local Hydroxyl Measurements By Radiocarbon And Fage Techniques, Malcolm J. Campbell, Brad D. Hall, John C. Sheppard, Philip L. Utley, Robert J. O'Brien, Thomas M. Hard, Linda Acha George
Environmental Science and Management Faculty Publications and Presentations
A direct intercomparison of near-surface tropospheric HO concentration measurements by two different techniques was made in October–November 1992 at a rural site near Pullman, Washington. The atmosphere at the site is believed to contain low levels of anthropogenic pollution. The instruments' inlets were located at the same height (3.5 m) above the ground and were separated by 10 m along a line normal to the prevailing wind. Readings of the FAGE3 and radiocarbon instruments showed a high correlation (r² = 0.74) despite HO concentrations that were frequently near the detection limit of the instruments. An unweighted least squares regression shows …
Fage Determination Of Tropospheric Ho And Ho₂, Linda Acha George, Thomas M. Hard, Robert J. O'Brien
Fage Determination Of Tropospheric Ho And Ho₂, Linda Acha George, Thomas M. Hard, Robert J. O'Brien
Environmental Science and Management Faculty Publications and Presentations
FAGE (fluorescence assay with gas expansion) was developed as a sensitive technique for the detection of low-concentration free radicals in the atmosphere. The application of FAGE to tropospheric hydroxyl (H0) and hydroperoxyl (H0₂) radicals has yielded calibrated measurements of both species in both clean air and highly polluted urban air. For HO calibration, a continuously stirred tank reactor provides a uniform external HO concentration, which can be measured by gas chromatography of an HO-reactive hydrocarbon. The aerodynamics of the air-sampling process has been modeled computationally, with results that agree with empirical observations of the effects of nozzle diameter on HO …
Some Relationships Between Sedimentary Trace Metal Concentrations And Freshwater Phytoplankton And Sedimentary Diatom Species Composition, Allan Hayes Vogel
Some Relationships Between Sedimentary Trace Metal Concentrations And Freshwater Phytoplankton And Sedimentary Diatom Species Composition, Allan Hayes Vogel
Dissertations and Theses
Sediments from 21 Oregon lakes were analyzed for seven metals (Fe, Mn, Zn, Cu, Co, Ni, V) in three forms (exchangeable, organic+sulfides, and oxyhydroxides+ oxides+ carbonates) using a sequential fractionation procedure. The summer epilimnetic filterable concentration of an eighth (Mo) was also determined. Sedimentary diatom remains and summer phytoplankton populations of the lakes were correlated with the 22 metal parameters and with conservative water chemistry parameters, estimators of lake productivity, and watershed geology. Both the sedimentary metals and the two populations of primary producers correlated best with the ecoregions of Omernik and Gallant (1986). A number of species possessed correlations …
Carbon Monoxide In The Antarctic Atmosphere: Observations Of Decreasing Concentrations, M. A. K. Khalil, R. A. Rasmussen
Carbon Monoxide In The Antarctic Atmosphere: Observations Of Decreasing Concentrations, M. A. K. Khalil, R. A. Rasmussen
Environmental Science and Management Faculty Publications and Presentations
Hydroxyl radicals remove hundreds, perhaps thousands, of organic gases from the atmosphere and are often regarded as am index of the oxidizing capacity of the Earth's atmosphere (Thompson 1992). In recent years, there have been growing concerns that, over the past century and now, human activities may be depleting hydroxyl concentrations by adding huge amounts of carbon monoxide and methane to the atmosphere. Reduction in the hydroxyl concentrations can then indirectly lead to more global warming, stratospheric ozone depletion, and other disturbances in atmospheric chemistry. Carbon monoxide (CO) is a key component in the determination of hydroxyl radical (OH) concentrations: …
Fage Measurements Of Tropospheric Ho With Measurements And Model Of Interferences, Thomas M. Hard, A. A. Mehrabzadeh, C. Y. Chan, Robert J. O'Brien
Fage Measurements Of Tropospheric Ho With Measurements And Model Of Interferences, Thomas M. Hard, A. A. Mehrabzadeh, C. Y. Chan, Robert J. O'Brien
Environmental Science and Management Faculty Publications and Presentations
Ambient HO measurements by low-pressure laser-excited fluorescence with chemical modulation, and supporting ozone and water-vapor data, are presented for periods in May and August 1987. The observed peak daytime ambient HO concentrations in Oregon are in the range (2.5 to 8) times106 molecules cm⁻³ and show small negative offsets due to photochemical interference. Direct measurements of the interference at fixed [O₃] give the dependence on ambient [H₂O] and on the modulating reagent [isobutane]. At ambient [O₃]=30 p.p.b. and 10 torr H₂O, with excitation and detection at a total pressure of 4 torr, the net interference is equal to [HO]=-1.3times10⁶ molecule …
Diurnal Ho₂ Cycles At Clean Air And Urban Sites In The Troposphere, Thomas M. Hard, C. Y. Chan, A. A. Mehrabzadeh, Robert J. O'Brien
Diurnal Ho₂ Cycles At Clean Air And Urban Sites In The Troposphere, Thomas M. Hard, C. Y. Chan, A. A. Mehrabzadeh, Robert J. O'Brien
Environmental Science and Management Faculty Publications and Presentations
HO₂ concentrations have been determined at two Oregon sites for continuous periods of 36 to 48 hours, using fluorescence assay with gas expansion. At the sea level coastal site (45degN 124degW), NNW winds prevailed during daytime, and a point measurement of very low total nonmethane hydrocarbon concentration indicated the presence of remote tropospheric air of oceanic origin. At the urban site, HO₂ was determined during moderately low ozone pollution levels. At both sites, maximum daily [HO₂] was in the range of 1-2times10⁸ cm⁻³ under clear-sky conditions, with an estimated overall uncertainty of 40%.
Studies Of Ecological Factors That Affect The Population And Distribution Of The Western Gray Squirrel In Northcentral Oregon, Susan Ann Foster
Studies Of Ecological Factors That Affect The Population And Distribution Of The Western Gray Squirrel In Northcentral Oregon, Susan Ann Foster
Dissertations and Theses
The western gray squirrel (Sciurus griseus griseus Ord) occur only in the Pacific states and in a small corner of extreme western Nevada. Field studies of aspects of the ecology of the most widely distributed subspecies of western gray squirrel (S. griseus) were conducted at three sites in the ponderosa pine-Oregon white oak zone on the eastern slopes of Mt. Hood, Wasco County, Oregon, between 1981 and 1989. From 1981 through 1987, a Hunter Cooperation Program provided remains of squirrels shot during the annual late summer-early autumn hunting season. Other data were gathered through capture and release studies, radiotelemetry, and …
Third-Generation Fage Instrument For Tropospheric Hydroxyl Radical Measurement, C. Y. Chan, Thomas M. Hard, A. A. Mehrabzadeh, Robert J. O'Brien
Third-Generation Fage Instrument For Tropospheric Hydroxyl Radical Measurement, C. Y. Chan, Thomas M. Hard, A. A. Mehrabzadeh, Robert J. O'Brien
Environmental Science and Management Faculty Publications and Presentations
The authors have constructed a single-stage, frequency-doubled, copper vapor laser-pumped dye laser to be used in the measurement of atmospheric hydroxyl radical concentrations. This laser can be tuned to either the 1← 0 or 0← 0 vibrational transition in the electronic transition ²Sigmalarr²Pi. A new photon counting instrument is used for HO fluorescence detection. Theoretical and experimental studies of instrument performance show better sensitivities and reduced photolytic interferences than have been possible with previous systems based upon Nd:YAG pumping.
Instrumentation For Multi-Electrode Voltammetry, I-Pin Ho
Instrumentation For Multi-Electrode Voltammetry, I-Pin Ho
Dissertations and Theses
When metal pollutants exist in natural water, their toxicity is dramatically dependent on the chemical species. Numerous sophisticated techniques and instruments have been developed to detect metal pollutants at very low concentration levels. However, one important factor is often ignored, i.e., rarely is species determination required. Electrochemical (EC) methods have the particular advantage of being, in principle, a species-sensitive method rather than an element-sensitive method for the study of metal speciation in natural waters.
The goal of this research was to develop an instrument using the EC technique for speciation and general voltammetric studies. It was accomplished by designing a …
Interference Suppression In Ho Fluorescence Detection, Thomas M. Hard, Robert J. O'Brien, T. B. Cook, G. A. Tsongas
Interference Suppression In Ho Fluorescence Detection, Thomas M. Hard, Robert J. O'Brien, T. B. Cook, G. A. Tsongas
Environmental Science and Management Faculty Publications and Presentations
In this Letter we report preliminary results on a sampling method that greatly reduces the above interferences relative to hydroxyl fluorescence.
Spatial Variations In The Intra-Urban Response To A Noise Source, Wilbur David Conder
Spatial Variations In The Intra-Urban Response To A Noise Source, Wilbur David Conder
Dissertations and Theses
Most research on the urban sonic environment has been recent. One finding has been that physical noise exposure indices calibrate poorly with human noise response. The vagaries of human response to noise have given impetus to research to isolate the factors that differentiate human response to noise. The present thesis continues this research.
The thesis specifies human noise response to occur on three levels: awareness, annoyance, and complaint. The factors that structure each level of noise response are identified in the published Iiterature.
Noise awareness is a function of noise exposure. Noise annoyance is a function of noise exposure to …
Adsorption Of Sulfur Dioxide On Douglas Fir Woodchips, Uen-Ping David Wang
Adsorption Of Sulfur Dioxide On Douglas Fir Woodchips, Uen-Ping David Wang
Dissertations and Theses
In recent years, people have raised their alertness to the hazard of air pollution. Sulfur dioxide is one of the most dangerous chemical compounds among those air pollutants. A study on removing sulfur dioxide from an air stream by adsorption using wood chips as the adsorbent is presented in this thesis.
The reason for using wood as an adsorbent is that wood is a porous material and possesses a large surface of cell cavities which can hold a great amount of moisture. As sulfur dioxide gas is passed through the wood bed, it would be either condensed in the cell …