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At least 595 records · Page 33Linked to original sources
USGS2011

Effects of rodent species, seed species, and predator cues on seed fate

Seed selection, removal and subsequent management by granivorous animals is thought to be a complex interaction of factors including qualities of the seeds themselves (e.g., seed size, nutritional quality) and features of the local habitat (e.g. perceived predator risk). At the same time, differential seed selection and dispersal is thought to have profound effects on seed fate and potentially vegetation dynamics. In a feeding arena, we tested whether rodent species, seed species, and indirect and direct predation cues influence seed selection and handling behaviors (e.g., scatter hoarding versus larder hoarding) of two heteromyid rodents, Ord's kangaroo rat (Dipodomys ordii) and the Great Basin pocket mouse (Perognathus parvus). The indirect cue was shrub cover, a feature of the environment. Direct cues, presented individually, were (1) control, (2) coyote (Canis latrans) vocalization, (3) coyote scent, (4) red fox (Vulpes vulpes) scent, or (5) short-eared owl (Asio flammeus) vocalization. We offered seeds of three sizes: two native grasses, Indian ricegrass (Achnatherum hymenoides) and bluebunch wheatgrass (Pseudoroegneria spicata), and the non-native cereal rye (Secale cereale), each in separate trays. Kangaroo rats preferentially harvested Indian ricegrass while pocket mice predominately harvested Indian ricegrass and cereal rye. Pocket mice were more likely to scatter hoard preferred seeds, whereas kangaroo rats mostly consumed and/or larder hoarded preferred seeds. No predator cue significantly affected seed preferences. However, both species altered seed handling behavior in response to direct predation cues by leaving more seeds available in the seed pool, though they responded to different predator cues. If these results translate to natural dynamics on the landscape, the two rodents are expected to have different impacts on seed survival and plant recruitment via their different seed selection and seed handling behaviors.

Acta Oecologica↗
USGS2005

Modeling effects of bank friction and woody bank vegetation on channel flow and boundary shear stress in the Rio Puerco, New Mexico

[1] We have applied a physically based model for steady, horizontally uniform flow to calculate reach-averaged velocity and boundary shear-stress distributions in a natural stream with woody vegetation on the channel banks. The model calculates explicitly the form drag on woody plant stems and includes the effects of vegetation on the boundary shear stress, velocity, and turbulence fields. Average channel shapes, bed gradients, and shrub characteristics were determined for four long, internally similar reaches covering an 81 -km segment of the lower Rio Puerco, in north-central New Mexico. Hydraulic geometries for each of three flow events were determined from reach-average channel shapes, slopes, and measured silt-line heights above the bed. Model results show that friction on the lateral boundaries reduced the boundary shear stress in the center of the Rio Puerco channel by as much as 20%. In reaches with moderate to dense bank shrubs, perimeter-averaged boundary shear stresses were reduced by almost 40% during near bankfull flows. Model-calculated discharges for all three flow events indicate there was a loss of about 40% of the upstream discharge through the 81-km river segment. Infiltration rates estimated from discharge losses during the quasi-steady peak flows and areas of the bed and banks suggest rates of flow loss into the silty sand of the upper banks are about 8 times greater than rates of loss into the clayey silt-covered bed and lower banks.

Journal of Geophysical Research F: Earth Surface↗
USGS1988

Changes in the morphometry of Las Vegas Wash and the impact on water quality

Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mean. Over 80 percent of the normal discharge of approximately 3.4 m 3 /s (120 ft 3 /s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly reduced the wetland area within Las Vegas Wash. The reduction in wetland area shortened water travel time in the wash and affected water quality. The primary impacts on the water entering Lake Mead have been an increase in temperature, a decrease in dissolved oxygen concentration, and an increase in ammonia levels. Other physical-chemical parameters and changes in nutrient transformations are also discussed.

Nevada↗
USGS2024

First records distribution models to guide biosurveillance for non-native species

Quickly locating new populations of non-native species can reduce the ecological and economic costs of species invasions. However, the difficulty of predicting which new non-native species will establish, and where, has limited active post-border biosurveillance efforts. Because pathways of introduction underlie spatial patterns of establishment risk, an intuitive approach is to search for new non-native species in areas where many non-native species have first been detected in the past. We formalize this intuition via first records distribution models (FRDMs), which apply species distribution modeling methods to the collection of first occurrence records across species (i.e. one record per species). We define FRDMs as statistical models that quantify environmental conditions associated with species' first naturalized records to predict spatial patterns of establishment risk. We model the first records of non-native plants in the conterminous USA as a proof-of-concept. The novelty of FRDMs is that their inferences apply not just to the species that contributed data; they provide a rigorous framework for predicting hotspots of invasion for new non-native taxa that share a pathway of introduction with the modeled species. FRDMs can guide survey efforts for new non-native taxa at multiple scales and across ecosystems.

conterminous United States↗
USGS1996

Watersheds: where we live

We all live in a watershed. Animals and plants all live there with us. Everyone affects what happens in a watershed by how we treat the natural resources. So what is a watershed? It is the land area that drains water to a stream, river, lake, or ocean. Water travels over the Earth's surface across forest land, farm fields, pastures, suburban lawns, and city streets, or it seeps into the soil and makes its way to a stream as local ground water. Watersheds come in many different shapes and sizes. Some contain mountains and hills, and others are nearly flat. A watershed can be affected by many different activities and events. Construction of cities and towns, farming, logging, and the application and disposal of many garden and household chemicals can affect the quantity and quality of water flowing from a watershed.

General Information Product↗
USGS2008

Water Availability--The Connection Between Water Use and Quality

Water availability has become a high priority in the United States, in large part because competition for water is becoming more intense across the Nation. Population growth in many areas competes with demands for water to support irrigation and power production. Cities, farms, and power plants compete for water needed by aquatic ecosystems to support their minimum flow requirements. At the same time, naturally occurring and human-related contaminants from chemical use, land use, and wastewater and industrial discharge are introduced into our waters and diminish its quality. The fact that degraded quality limits the availability and suitability of water for critical uses is a well-known reality in many communities. What may be less understood, but equally true, is that our everyday use of water can significantly affect water quality, and thus its availability. Landscape features (such as geology, soils, and vegetation) along with water-use practices (such as ground-water withdrawals and irrigation) govern water availability because, together, they affect the movement of chemical compounds over the land and in the subsurface. Understanding the interactions of human activities with natural sources and the landscape is critical to effectively managing water and sustaining water availability in the future.

Fact Sheet↗
USGS1970

Geochemical Survey of Missouri: Plans and progress for second six-month period (January-June 1970)

This is the second six-month progress report on studies in environmental geochemistry in the State of Missouri initiated on behalf of the Environmental Health Surveillance Project in July, 1969. The studies are being made in support of epidemiological investigations of the Surveillance Project to provide general information pertaining to the occurrence and distribution of chemical elements in rocks, soils, plants, and water throughout the State. Emphasis is placed on the occurrence and distribution of elements in the natural environment, though studies of the effects of some types of chemical pollution are necessarily included. The objectives and plans for the three phases of the Survey that are directed at the rocks, soils, and vegetation are described in the progress report for the first six-month period; those for the phase of the project concerned with the water are described by Gerald L. Feder in a later section of the present report. The addition of this latter phase significantly expands the scope of our study and increases its relevance to studies of human and animal health. Mr. Feder has a valuable background in the geology and hydrology of Missouri, and we are most pleased that he has joined us in this effort.

Missouri↗
USGS2022

Terrestrial ecosystem modeling with IBIS: Progress and future vision

Dynamic Global Vegetation Models (DGVM) are powerful tools for studying complicated ecosystem processes and global changes. This review article synthesizes the developments and applications of the Integrated Biosphere Simulator (IBIS), a DGVM, over the past two decades. IBIS has been used to evaluate carbon, nitrogen, and water cycling in terrestrial ecosystems, vegetation changes, land-atmosphere interactions, land-aquatic system integration, and climate change impacts. Here we summarize model development work since IBIS v2.5, covering hydrology (evapotranspiration, groundwater, lateral routing), vegetation dynamics (plant functional type, land cover change), plant physiology (phenology, photosynthesis, carbon allocation, growth), biogeochemistry (soil carbon and nitrogen processes, greenhouse gas emissions), impacts of natural disturbances (drought, insect damage, fire) and human induced land use changes, and computational improvements. We also summarize IBIS model applications around the world in evaluating ecosystem productivity, carbon and water budgets, water use efficiency, natural disturbance effects, and impacts of climate change and land use change on the carbon cycle. Based on this review, visions of future cross-scale, cross-landscape and cross-system model development and applications are discussed.

Journal of Resources and Ecology↗
USGS2025

Nature-based solutions extend the lifespan of a regional levee system under climate change

Nature-based solutions are receiving increasing attention as a cost-effective climate adaptation strategy. Horizontal levees are nature-based adaptation solutions that include a sloping wetland habitat buffer fronting a levee. They can offer a hybrid solution to reinforce traditional levees in estuarine areas—plants on the horizontal levee can provide wave attenuation benefits as well as habitat benefits, but how the design of horizontal levees influences risk of levee failure remains unquantified. We use a hydrodynamic model, XBeach non-hydrostatic (XB-NH), to assess the stability and sustainability of existing levees and determine how hybrid nature-based climate adaptation measures can reduce the risk of overtopping on levees in San Francisco Bay. We compare overtopping rates in the existing levee system and in a variety of nature-based adaptation scenarios using a range of widths and slopes of horizontal levees to assess how horizontal levees perform in reducing risk of flooding, both with present day conditions and sea level rise. We show that climate change will challenge existing levee flood defenses in San Francisco Bay and increase the risk of overtopping, and that the nature-based solution of horizontal levees can meaningfully reduce risk of overtopping while simultaneously supporting marsh habitat. Flood risk reduction and habitat provision are both maximized with more gradually sloping and wider horizontal levee designs. Results show that the risk of overtopping can be reduced by up to 30% with horizontal levees. This analysis provides insight into horizontal levee design considerations and a methodological approach to adapt levees to prepare for climate change in urban wave-exposed estuaries. We show that horizontal levees can support preparation for the projected impacts of sea level rise (SLR) while simultaneously providing new intertidal wetland habitat.

California↗
USGS1967

Swatara Creek basin of southeastern Pennsylvania: An evaluation of its hydrologic system

Local concentrations of population in the Swatara Creek basin of Pennsylvania find it necessary to store, transport, and treat water because local supplies are either deficient or have been contaminated by disposal of wastes in upstream areas. Water in the basin is available for the deficient areas and for dilution of the coal-mine drainage in the northern parts and the sewage wastes in the southern parts. Swatara Creek drains 576 square miles just east of Harrisburg, Pa., and is the largest tributary to the Susquehanna River from the north side below Harrisburg. It rises in the southern Pocono Mountains and flows southwestward across the Lebanon Plateau. On an average day Swatara Creek discharges more than 630 million gallons into the Susquehanna River at Middletown, Pa. In a year this amounts to about 23 inches of water over the entire basin and is the residual from an average annual precipitation of 45.5 inches. During an average year the flow in Swatara Creek from the upper third of the basin above Harper Tavern is always greater than 1,300 mgd (million gallons per day) for at least 15 days and is always greater than 25 mgd for at least 350 days. The daily streamflow from the basin averages 1.1 mgd per sq mi, but yields from different areas range from 0.97 to 1.22 mgd per sq mi. These variations are caused chiefly by differences in precipitation and land cover. The area of lowest yield is in the valleys west of Tremont, and the highest yields are in the Upper and Lower Little Swatara Creek subbasins. At high and medium stages the chemical character of the water in the streams is suitable for public and private supplies. At lower stages, defending on the areas and the amounts of contamination by coal-mine drainage and sewage pollution, the natural flow may require some treatment. At low stages the chemical characteristics of the natural flow not affected by man is almost identical with that of the ground water in the area drained by the stream. In general, the total dissolved solids range from about 25 to 400 parts per million and the hardness is as much as about 300 parts per million. The ground-water increment to the base flow of Swatara Creek averages about 240 mgd, or about 8.8 inches annually, for the basin. Generally, ground-water supplies in amounts of less than 0.5 mgd can be developed south of Blue Mountain. Supplies of several million gallons per day have been developed for industrial use from the permeable limestones in the south-central part of the basin. More intensive investigation in other parts of the basin would indicate areas where supplies of more than 0.5 mgd could be developed from properly spaced wells. The chemical character of water from wells depends largely on the host rock. In highly soluble rocks water contains large amount of dissolved solids; in more resistant rocks concentrations are lower. The chemical character of unpolluted ground water generally reflects the composition of the more readily soluble minerals in the local geologic environment. Areas contaminated by septic- tank effluent may have above normal amounts of nitrate and detergent products. Except where polluted, most ground water is suitable for public and industrial uses without extensive treatment. Sites for storage of surface water exist in the part of the basin lying in the valley and ridge area. As much as 30 to 40 percent of the annual flow could be impounded for release as low-flow augmentation for dilution of mine drainage and other wastes in the basin. Low sediment yields of supplying drainage areas would ensure a long life expectancy of reservoirs at these sites. Overbank flooding of the main stem of the Swatara Creek and its tributaries has occurred many times in the past. However, it has not been a hazard because urban development has not encroached on the flood plain. An inundation map of the August 1933 flood provides a basis that urban planners may use to avoid future damage. As water in the Swatara Creek moves downstream to the Susquehanna River, the flow is influenced consecutively by a large annual rainfall on the northern valley and ridge area, the wastes of surface and subsurface coal-mining activities, and less annual rainfall on the part of the basin lying in the Lebanon Plateau area; the flow is supplemented and further influenced by many tributaries and by the industrial and domestic wastes that are carried by these secondary streams. The annual precipitation ranges from 52 inches at the east edge and 49 inches at the west edge of the mountainous part of the basin to about 41 inches at the southwestern part at Middletown. The rainfall generally is adequate during the growing season to mature the crops. The mean annual temperature at Lebanon is about 52°F, and the growing season is about 180 days. In this report the basin has been divided into eight hydrologic zones, leased on runoff, natural use of water, and chemical character of water. Four zones lie in the valley and ridge area, three lie in the Lebanon Plateau area, and one lies in the highland along the southeastern basin boundary. In each of the zones the hydrologic characteristics are virtually the same, but they may be completely different from those in adjacent zones. The boundaries of the zones generally coincide with boundaries between geologic formations, and the areas in each zone include rocks of similar influence on water. Streams in zone 4 at the northeast edge of the plateau have the highest average surface runoff from 1.2 to 1.1 mgd per sq mi whereas those in zone 2 at the northwest edge of the valley and ridge area have the lowest, about 1.0 mgd. Streams in zone 8, along the southeast edge of the basin, have the largest sustained low-flow yield, about 0.26 to 0.19 mgd per sq mi; those in zone 5 overlying the Martinsburg Shale east of Harrisburg have the smallest sustained low-flow yields, 0.03 to 0.01 mgd. Streams in the limestone area of zone 7 have the greatest range in low-flow yields in any one zone from 0.60 to 0 mgd per sq mi. Low-flow yields in zones 1 through 4 range from 0.13 to 0.03 mgd per sq mi. Surface flows from zones 1 and 2 are generally acidic and contain high concentrations of sulfate, iron, and total dissolved solids especially where contaminated with mine wastes. Surface flows from zones 3 and 4 are dilute, slightly alkaline, and suitable for public water supplies. Surface flows from zones 5, 6, and 7 are alkaline and contain moderate concentrations of dissolved solids with waters of highest hardness occurring in zone 7. Surface flows from zone 8 are dilute to moderately mineralized and are relatively high in silica concentration. Nitrate concentrations are high in surf Fee flows below sewage outfalls and in ground water contaminated by septic tank effluent and industrial wastes. Average annual sediment yields of 550 to 650 tons per square mile are characteristic of zones 1 and 2 where strip mining has destroyed the forest cover and coal culm is carried into the streams. From agricultural lands on the Martinsburg Shale in zones 5 and 6, annual sediment yields range from 300 to 350 tons per square mile; but from agricultural lands on the siliceous rocks in zone 8 and zones 3 and 4 in the valley and ridge area, the sediment yield ranges from 200 to 250 tons annually per square mile. Lowest annual sediment yields in the basin are in the forested areas of siliceous rocks in zones 2, 3, 4, and 5, and in the sinkhole topography of the limestones in zone 7 where the yield ranges from 30 to 35 tons and 50 to 60 tons per square mile, respectively. The amount of ground water that can be developed in the basin is dependent on the ability of the underlying rocks to yield water to wells. More than 300 gpm (gallons per minute) can be obtained from wells in alluvial materials in the valley bottoms and in some of the limestones where large solution channels and fractures are penetrated by the wells. From 50 to 300 gpm can be obtained from wells in loosely cemented sandstones and in fractured limestones. From 10 to 50 gpm can be developed from wells in the shales and harder sandstones. The most dense rocks will yield from 1 to 10 gpm from fractures and crevices. Most wells yield water from the upper 350 feet of the formation, for this part contains the most fractures or solution channels. Studies show that the velocity at which a contaminant will move downstream in the basin is related to the discharge of the stream at the time. At a stream discharge of about 400 mgd at Pine Grove, a contaminant in Swatara Creek would require about 40 hours to move from Pine Grove to Middletown. As a result of dispersion and dilution, the maximum concentration of the contaminant at Middletown would be less than 20 percent the concentration at Pine Grove under these conditions. An evaluation of the availability of water in the basin indicates that about I,239 mgd enters as precipitation, 630 mgd leaves as streamflow, 580 mgd is evaporated and transpired, and 56 mgd is diverted for use by man. Not all the diversions for man's use are lost to the basin, as about 27 mgd is returned as sewage for reuse. About one-fourth of the waste water is returned to the ground and the remainder to stream drainageways. Of that diverted by man, 11.6 mgd is used for public supply and 44.4 mgd for industrial and private supplies. Diversions of streamflow furnish 86 percent of the public supply and 27 percent of the industrial supply, and ground-water sources yield the remainder. Municipal and private sewage treatment plants are upgrading the waste water in many places, but no provisions are being made for treatment other than natural dilution and assimilation for the 15 mgd of coal-nine drainage in the northern part of the basin. Technology for economic treatment of mine water is not available at this time, although research in this field is being done. Urbanization eastward from Harrisburg and around Lebanon has increased the population density of the basin. Densities of 500 people per square mile and water use exceeding 2.0 mgd per sq mi can be expected in the future. By the year 2000 the population of the basin may increase 60 percent; and if the per capita rate of use increases 0.5 percent per year the domestic requirements for water will be about two times the present use, or 23 mgd. Similarly, if the present 1:4 ratio of domestic use to industrial use of water continues, at least 89 mgd will be needed for industry in the future. Although an increase to twice the present use of water can be foreseen, or 112 mgd, water for the dilution and assimilation of wastes from treatment systems are not included. Providing water for dilution of wastes from treatment plants has not been a problem, but in the future the amounts needed for this purpose will be greater as the population increases. As water becomes more valuable, treatment of sewage wastes to reduce the biochemical-oxygen-demand load by at least 80 to 90 percent will be necessary to conserve water for more productive uses. As much as 100 mgd may be needed for waste dilution in the basin by year 2000. The present trends in suburban and light industrial development will probably persist in the basin. Problems arising through changes in economic value of water, conflicts in use, and alternatives in development are typical of those confronting the manager of a water-resource system.

Pennsylvania↗
USGS2024

Quantifying the coastal hazard risk reduction benefits of coral reef restoration in the U.S. Virgin Islands

Coastal habitat restoration, especially of coral reef ecosystems, can significantly reduce the exposure of coastal communities to natural hazards and, consequently, the risk of wave-driven flooding. Likewise, reef degradation can increase coastal flood risks to people and property. In this study, the valuation of coral reefs in the United States Virgin Islands (USVI), along the coasts of St. Croix, St. John, and St. Thomas, demonstrated the social and economic benefits provided by these natural defenses. Across the territory, more than 481 people and $31.2 million of infrastructure were estimated to receive protection from coral reefs per year (2010 U.S. dollars). In 2017, Hurricanes Irma and Maria significantly damaged coral reefs throughout the archipelago. By combining engineering, ecological, geospatial, social, and economic data and tools, this study provided a rigorous valuation of where potential coral reef restoration projects could help rebuild these damaged habitats and decrease the risks from coastal hazards faced by USVI’s reef-fronted communities. Multiple restoration scenarios were considered in the analysis, two of which are detailed in this report. These include (1) ‘Ecological’ restoration, where restoration creates a structure that is 0.25 m high and 25-m-wide reef, and (2) ‘Hybrid’ restoration, where restoration creates a structure that is 1.25 m high and 5 m wide. There are many ways that such structures could be developed. In the hydrodynamic analyses, there are no assumptions about how the restoration is developed. Many practitioners of both coral (and oyster reef) restoration consider that a reef height of 0.25 m might be delivered from planting corals alone and that 1.25 m might require a combination of artificial structures and coral planting. In a third scenario, the analysis investigated the reduction of protection benefits that would occur through the reduction of 1 meter of naturally occurring reef height due to reef degradation. The reduction of protection due to the loss of reefs can also be interpreted as the protection value of the existing reefs. In all studied restoration scenarios, it was assumed that the planting of corals would enhance hydrodynamic roughness, effectively dissipating incident wave energy and reducing the potential for coastal flooding. A standardized approach was employed to strategically locate potential restoration projects along the entire linear extent of existing reefs bordering the USVI, and to identify where coral reef restoration could offer valuable benefits in flood reduction. Potential restoration projects were only located within the existing distribution of reefs across the region, even though numerous sites were positioned far offshore (2-3 km), and some were at relatively deep depths (up to 7 m). Risk-based valuation approaches were followed to delineate flood zones at a 10 m 2 resolution along the entire region's reef-lined shorelines for all the potential coral reef restoration scenarios. These were subsequently compared to flood zones without coral reef restoration. The potential reduction in coastal flood risk provided by coral reef restoration, and the protection value of existing reefs, were quantified utilizing the latest information available at the time of analysis from the U.S. Census Bureau, Federal Emergency Management Agency (FEMA), and Bureau of Economic Analysis for return-interval storm events. The change in Expected Annual Damages (EAD), a metric indicating the annual protection gained due to coral reef restoration, was calculated based on the damages associated with each storm probability. The findings suggest that the benefits of reef restoration are spatially variable within the USVI. In some areas, the analysis showed limited benefits from reef restoration, which may be attributed to the depth or offshore distances of proposed restoration sites. However, there were a number of key areas where reef restoration could have substantial benefits for flood risk reduction. The annual flood risk reduction attributed to potential ‘ecological’ coral reef restoration in the USVI was 99 people and $6.1 million (2010 U.S. dollars). The Benefit-to-Cost Ratio (BCR) for this restoration approach was found to be larger than 1 (i.e., cost-effective) along 11% of the St. Croix coastline, 4.9% of the St. John coastline, and 8.7% of the St. Thomas coastline. This analysis offers stakeholders and decision-makers a spatially explicit and rigorous evaluation that illustrates how, where, and when potential coral reef restoration efforts in St. Croix, St. John, and St. Thomas could be instrumental to reducing coastal storm-induced flooding. Understanding areas where reef management, recovery, and restoration could effectively reduce climate hazard-related risks is crucial to protect and enhance the resilience of coastal communities in USVI.

Report↗
USGS2007

Natural restoration of degraded rangeland ecosystem in Heshan hilly land

This study examined the 20-yr trend of natural restoration of a degraded rangeland ecosystem after disturbance in Heshan hilly land. The results showed that herbs and shrubs were the dominant plants in the community and only a small number of the shade-intolerant tree species had invaded, showing the characteristics of assembly of pioneer communities. The organic matter content, soluble nitrogen, available phosphorus and available potassium had recovered to the level of the local climax community. Part of the ecological functions such as water and soil conservation had also recovered. While the functions of water and soil conservation recovered first, more time was needed for productivity and other functions to completely recover, suggesting the idiosyncratic nature of different ecosystem variables in response to time and microclimate change. Particularly, nutrient cycling recovered very slowly by natural restoration and artificial plantation may be necessary to accelerate the restoration process. ?? 2007 Ecological Society of China.

Acta Ecologica Sinica↗
USGS2009

Selected Natural Attenuation Monitoring Data, Operable Unit 1, Naval Undersea Warfare Center, Division Keyport, Washington, 2007 and 2008

Previous investigations indicate that natural attenuation and biodegradation of chlorinated volatile organic compounds (VOCs) are substantial in groundwater beneath the 9-acre former landfill at Operable Unit 1 (OU 1), Naval Undersea Warfare Center, Division Keyport, Washington. Phytoremediation combined with on-going natural attenuation processes was the preferred remedy selected by the Navy, as specified in the Record of Decision for the site. The Navy planted two hybrid poplar plantations on the landfill in spring 1999 to remove and to control the migration of chlorinated VOCs in shallow groundwater. The U.S. Geological Survey (USGS) has continued to monitor groundwater geochemistry to ensure that conditions remain favorable for contaminant biodegradation as specified in the Record of Decision. In this report are groundwater geochemical and selected VOC data collected at OU 1 by the USGS during June 18-21, 2007, and June 16-18, 2008, in support of long-term monitoring for natural attenuation. For 2007 and 2008, strongly reducing conditions (sulfate reduction and methanogenesis) most favorable for reductive dechlorination of VOCs were inferred for 9 of 16 upper-aquifer wells and piezometers in the northern and southern phytoremediation plantations. Predominant redox conditions in groundwater from the intermediate aquifer just downgradient from the landfill remained mildly reducing and somewhat favorable for reductive dechlorination of VOCs. Dissolved hydrogen (H2) concentrations measured in the upper aquifer during 2007 and 2008 generally have been lower than H2 concentrations measured before 2002. However, widespread and relatively high methane and sulfide concentrations indicate that the lower H2 concentrations measured do not support a trend from strongly to mildly reducing redox conditions because no widespread changes in groundwater redox conditions were identified that should result in less favorable conditions for the reductive dechlorination of the chlorinated VOCs. For the upper aquifer beneath the northern phytoremediation plantation, chlorinated VOC concentrations in 2007 and 2008 at most piezometers were similar to or slightly less than chlorinated VOC concentrations measured in previous years. The only chlorinated VOC positively detected at piezometers P1-1 and P1-5 was cis-1,2-dichloroethene (cis-DCE); most chlorinated VOC concentrations at piezometer P1-3 were at the lowest levels since monitoring began in 1999. Most VOC concentrations at piezometer P1-4 were similar to VOC concentrations measured in previous years except that vinyl chloride (VC) concentrations inexplicably increased from 280 micrograms per liter (ug/L) in June 2007 to 750 ug/L in June 2008. In 2008, measurement of the sum of concentrations of ethane and ethene, reductive dechlorination byproducts, was at the highest level at most northern plantation wells and piezometers, which is evidence of reductive dechlorination of chlorinated VOCs. For the upper aquifer beneath the southern phytoremediation plantation, chlorinated VOC concentrations in 2007 and 2008 at the piezometers were most often extremely high and they continued to vary considerable over space and between years. At piezometer P1-6, the total chlorinated VOC concentration increased from 380 ug/L in 2007 to more than 20,000 ug/L in 2008. At piezometer P1-7 in 2008, the concentrations of trichloroethene, cis-DCE, and VC were the highest to date, but total chlorinated VOC concentrations at piezometers P1-8, P1-9, and P1-10 in 2008 were relatively low compared to historical levels. The magnitude and persistence of chlorinated VOC concentrations indicate that non-aqueous phase liquid chloroethenes likely are beneath the southern plantation, and the temporal variability in concentrations likely is a result of variations in precipitation and groundwater levels interacting with the non-aqueous phase liquid. The reductive dechlorination byproducts ethane and ethene were detected at

Open-File Report↗
USGS2017

Competitive Interactions of Garlic Mustard ( Alliaria petiolata ) and Damesrocket ( Hesperis matronalis )

Competitive interactions between native plants and nonnative, invasive plant species have been extensively studied; however, within degraded landscapes, the effect of interspecific interactions among invasive plants is less explored. We investigated a competitive interaction between two sympatric, invasive mustard species that have similar life history strategies and growth forms: garlic mustard and damesrocket. Greenhouse experiments using a full range of reciprocal density ratios were conducted to investigate interspecific competition. Garlic mustard had a negative effect on the final biomass, number of leaves, and relative growth rate in height of damesrocket. Survival of damesrocket was not negatively affected by interspecific competition with garlic mustard; however, garlic mustard showed higher mortality because of intraspecific competition. These results indicated that although garlic mustard has been observed to be the dominant species in this landscape, it may not completely outcompete damesrocket in all situations. Studies of invasive species in competition are important in degraded landscapes because this is the common situation in many natural areas.

Invasive Plant Science and Management↗
USGS1958

Some natural variations in the relative abundance of copper isotopes

The relative isotopic abundance of copper has been measured in a number of minerals and a few plant materials. Suites of samples from Michigan and the Colorado Plateau have been examined in more detail to determine if local variations due to isotopic exchange or diffusion could be found. The relative isotopic abundance of copper in specimens from several other localities was also determined. The variations noted were small but in some cases were felt to be significant because they were larger than the experimental error (0·1 per cent in the ratio). A total spread of −1 to +8 parts per mil compared to the standard was found in the specimens tested.

Geochimica et Cosmochimica Acta↗
USGS2014

Committee on chemistry of natural waters, 1939–40

The membership of this Committee is as follows: I. A. Dennison, National Bureau of Standards, Washington, D.C.; C. S. Scofield, Bureau of Plant Industry, Department of Agriculture, Washington, D.C.; D. G. Thompson, United States Geological Survey, Washington, D.C.; Prof. T. G. Thompson, University of Washington, Seattle, Washington; and C. S. Howard (Chairman), United States Geological Survey, Washington, D.C. The Committee arranged for the presentation of the following five papers at the 1940 Spring meeting: (1) Salt‐water intrusion in the Connecticut River, by C. S. Howard, United States Geological Survey; (2) Salinity‐movement and its causes in the Delaware River Estuary, by William D. Mason and Wallace R. Pietsch, Sun Oil Company; (3) Salinity of, lower Savannah River in relation to tidal action and stream‐flow, by William L. Lamar, United States Geological Survey; (4) Corrosion of ferrous and nonferrous metals and the behavior of metallic coatings in tidal marsh, by I. A. Dennison, National Bureau of Standards; (5) The contamination of underground waters by salt water near Parlin, New Jersey, by H. C. Barksdale, United States Geological Survey.

Eos, Transactions, American Geophysical Union↗
USGS2013

Fort Collins Science Center Ecosystem Dynamics branch--interdisciplinary research for addressing complex natural resource issues across landscapes and time

The Ecosystem Dynamics Branch of the Fort Collins Science Center offers an interdisciplinary team of talented and creative scientists with expertise in biology, botany, ecology, geology, biogeochemistry, physical sciences, geographic information systems, and remote-sensing, for tackling complex questions about natural resources. As demand for natural resources increases, the issues facing natural resource managers, planners, policy makers, industry, and private landowners are increasing in spatial and temporal scope, often involving entire regions, multiple jurisdictions, and long timeframes. Needs for addressing these issues include (1) a better understanding of biotic and abiotic ecosystem components and their complex interactions; (2) the ability to easily monitor, assess, and visualize the spatially complex movements of animals, plants, water, and elements across highly variable landscapes; and (3) the techniques for accurately predicting both immediate and long-term responses of system components to natural and human-caused change. The overall objectives of our research are to provide the knowledge, tools, and techniques needed by the U.S. Department of the Interior, state agencies, and other stakeholders in their endeavors to meet the demand for natural resources while conserving biodiversity and ecosystem services. Ecosystem Dynamics scientists use field and laboratory research, data assimilation, and ecological modeling to understand ecosystem patterns, trends, and mechanistic processes. This information is used to predict the outcomes of changes imposed on species, habitats, landscapes, and climate across spatiotemporal scales. The products we develop include conceptual models to illustrate system structure and processes; regional baseline and integrated assessments; predictive spatial and mathematical models; literature syntheses; and frameworks or protocols for improved ecosystem monitoring, adaptive management, and program evaluation. The descriptions in this fact sheet provide snapshots of our three research emphases, followed by descriptions of select current projects.

Fact Sheet↗
USGS2010

Polycyclic aromatic hydrocarbons in soil of the Canadian River floodplain in Oklahoma

The accumulation of polycyclic aromatic hydrocarbons (PAH) in soil, plants, and water may impart negative effects on ecosystem and human health. We quantified the concentration and distribution of 41 PAH (n = 32), organic C, total N, and S (n = 140) and investigated PAH sources using a chronosequence of floodplain soils under a natural vegetation succession. Soil samples were collected between 0- and 260-cm depth in bare land (the control), wetland, forest, and grassland areas near a closed municipal landfill and an active asphalt plant (the contaminant sources) in the north bank of the Canadian River near Norman, OK. Principal component, cluster, and correlation analyses were used to investigate the spatial distribution of PAH, in combination with diagnostic ratios to distinguish pyrogenic vs. petrogenic PAH suites. Total PAH concentration (SigmaPAH) had a mean of 1300 ng g(-1), minimum of 16 ng g(-1), and maximum of 12,000 ng g(-1). At 0- to 20-cm depth, SigmaPAH was 3500 +/- 1600 ng g(-1) (mean +/- 1 SE) near the contaminant sources. The most common compounds were nonalkylated, high molecular weight PAH of pyrogenic origin, i.e., fluoranthene (17%), pyrene (14%), phenanthrene (9%), benzo(b)fluoranthene (7%), chrysene (6%), and benzo(a)anthracene (5%). SigmaPAH in the control (130 +/- 23 ng g(-1)) was comparable to reported concentrations for the rural Great Plains. Perylene had a unique distribution pattern suggesting biological inputs. The main PAH contamination mechanisms were likely atmospheric deposition due to asphalt production at the 0- to 20-cm depth and past landfill operations at deeper depths.

Journal of Environmental Quality↗