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James P. Bennett

Publications and source records attributed to James P. Bennett.

27 records · Page 2Linked to original sources
USGS2001

User's Guide for Mixed-Size Sediment Transport Model for Networks of One-Dimensional Open Channels

This user's guide describes a mathematical model for predicting the transport of mixed sizes of sediment by flow in networks of one-dimensional open channels. The simulation package is useful for general sediment routing problems, prediction of erosion and deposition following dam removal, and scour in channels at road embankment crossings or other artificial structures. The model treats input hydrographs as stepwise steady-state, and the flow computation algorithm automatically switches between sub- and supercritical flow as dictated by channel geometry and discharge. A variety of boundary conditions including weirs and rating curves may be applied both external and internal to the flow network. The model may be used to compute flow around islands and through multiple openings in embankments, but the network must be 'simple' in the sense that the flow directions in all channels can be specified before simulation commences. The location and shape of channel banks are user specified, and all bedelevation changes take place between these banks and above a user-specified bedrock elevation. Computation of sediment-transport emphasizes the sand-size range (0.0625-2.0 millimeter) but the user may select any desired range of particle diameters including silt and finer (<0.0625 millimeter). As part of data input, the user may set the original bed-sediment composition of any number of layers of known thickness. The model computes the time evolution of total transport and the size composition of bed- and suspended-load sand through any cross section of interest. It also tracks bed -surface elevation and size composition. The model is written in the FORTRAN programming language for implementation on personal computers using the WINDOWS operating system and, along with certain graphical output display capability, is accessed from a graphical user interface (GUI). The GUI provides a framework for selecting input files and parameters of a number of components of the sediment-transport process. There are no restrictions in the use of the model as to numbers of channels, channel junctions, cross sections per channel, or points defining the cross sections. Following completion of the simulation computations, the GUI accommodates display of longitudinal plots of either bed elevation and size composition, or of transport rate and size composition of the various components, for individual channels and selected times during the simulation period. For individual cross sections, the GUI also allows display of time series of transport rate and size composition of the various components and of bed elevation and size composition.

Water-Resources Investigations Report↗
USGS1999

Changes in element contents of four lichens over 11 years in the Boundary Waters Canoe Area Wilderness, northern Minnesota

Four species of lichen ( Cladina rangiferina, Evernia mesomorpha, Hypogymnia physodes, and Parmelia sulcata ) were sampled at six locations in the Boundary Waters Canoe Area Wilderness three times over a span of 11 years and analyzed for concentrations of 16 chemical elements to test the hypotheses that corticolous species would accumulate higher amounts of chemical elements than terricolous species, and that 11 years were sufficient to detect spatial patterns and temporal trends in element contents. Multivariate analyses of over 2770 data points revealed two principal components that accounted for 68% of the total variance in the data. These two components, the first highly loaded with Al, B, Cr, Fe, Ni and S, and the second loaded with Ca, Cd, Mg and Mn, were inversely related to each other over time and space. The first component was interpreted as consisting of an anthropogenic and a dust component, while the second, primarily a nutritional component. Cu, K, Na, P, Pb and Zn were not highly loaded on either component. Component 1 decreased significantly over the 11 years and from west to east, while component 2 increased. The corticolous species were more enriched in heavy metals than the terricolous species. All four elements in component 2 in H. physodes were above enrichment thresholds for this species. Species differences on the two components were greater than the effects of time and space, suggesting that biomonitoring with lichens is strongly species dependent. Some localities in the Boundary Waters Canoe Area Wilderness appear enriched in some anthropogenic elements for no obvious reasons.

Minnesota↗
USGS1999

Geothermal elements in lichens of Yellowstone National Park, USA

Geothermal features (e.g. geysers, fumaroles, vents, and springs) emit gaseous mercury, sulfur and heavy metals and therefore, are natural sources of these elements in the atmosphere. Field studies of heavy metals in lichens in Italy have detected elevated concentrations near geothermal power plants, and have determined that the origin of mercury is from soil degassing, not soil particles. We studied this phenomenon in a geothermal area without power plants to determine the natural levels of mercury and other elements. Two common and abundant species of epiphytic lichens, Bryoria fremontii and Letharia vulpina , were collected at six localities in Yellowstone National Park, USA in 1998 and analyzed for 22 chemical elements. Thirteen elements differed significantly between species. Some elements were significantly higher in the southern part of the park, while others were higher in the north. Levels of most elements were comparable with those in other national parks and wilderness areas in the region, except Hg, which was unusually high. The most likely sources of this element are the geothermal features, which are known emitters of Hg. Multivariate analyses revealed strong positive associations of Hg with S, and negative associations with soil elements, providing strong evidence that the Hg in the lichens is the result of soil degassing of elemental Hg rather than particulate Hg directly from soils. Average Hg levels in the lichens were 140 p.p.b. in Bryoria and 110 p.p.b. in Letharia , but maxima were 291 and 243 p.p.b., respectively. In spite of this, both species were healthy and abundant throughout the park.

Idaho, Montana, Wyoming↗
USGS1997

Chemical element concentrations in four lichens on a transect entering Voyageurs National Park

A three factor transect study was conducted to test the hypothesis that chemical elements from air emissions in the vicinity of International Falls, Minnesota could not be detected in lichens along a 24 km transect reaching into Voyageurs National Park. It was hypothesized that element concentrations in lichens would decline exponentially downwind and would reach background values at a distance before the park boundary. Four species ( Cladina rangiferina, Evernia mesomorpha, Hypogymnia physodes , and Parmelia sulcata ) were sampled at ten sites for 3 years and 17 chemical elements were measured. The most notable result was a curvilinear geographic trend for many elements, which decreased from International Falls and then increased towards the park. This trend was significant for many anthropogenic elements, including S, Hg, Cd, and Cr, and for all four species. This type of distribution pattern has been observed in Hypogymnia physodes in other studies downwind of a steel mill and an oil refinery. Cladina , a ground-dwelling lichen, generally had lower tissue concentrations of the elements than the three epiphytic species. Tissue concentrations over the 3 years of sampling declined an average of 12%. Sufficient evidence exists to conclude that lichen tissue element concentrations in the vicinity of International Falls may be related to local air emissions, and that an exponential decline of element concentrations downwind of the sources does not apply to this situation.

Minnesota↗
USGS1996

Element concentrations on Hypogymnia physodes (L.) Nyl. after three years of transplanting along Lake Michigan

Improvements in air quality in air polluted areas are often followed by recolonization of habitats by sensitive lichens that had died out when air quality was worse. To test the hypothesis that air quality at Indiana Dunes National Lakeshore has improved such that lichens could recolonize the area, samples of a species that once grew in the park, Hypogymnia physodes , were transplanted from Door County, Wisconsin to the park and three other sites along the western shore of Lake Michigan, including one at the site of origin as a control. The lichens were sampled for 3 years and tissue concentrations of 20 chemical elements were measured. There were no significant differences between concentrations over the 3 year study duration at the control site in Door County, suggesting that transplanting itself had no impacts on tissue concentrations. All but two elements increased in concentration from north to south with the greatest increases occurring in the third year of the study. Lichens at Indiana Dunes at the end of the study had suffered severe mortality. Chromium increased the most from north to south but concentrations were not higher than maxima observed in other studies. Arsenic and sulfur, however, exceeded known toxic thresholds or maxima observed in other studies on this species. Four hypotheses are presented to explain the toxicity of elements to this species.

Indiana, Wisconsin↗
USGS1996

Similarities and life cycle distributions of floras of 22 national parks in the midwestern United States

Twenty-two midwestern U.S. national parks were studied to examine the similarities of their floras and analyses of the floras in each national park were used to construct groupings of these smaller sample areas at various similarity levels in order to classify larger floristic areas. The parks were not on average very similar based on Jaccard's similarity index. The maximum average park similarity was 21% (St. Croix National Scenic Riverway), and the maximum park pair similarity was just over 55% for Isle Royale National Park and Pictured Rocks National Lakeshore. The average similarity of parks increased with park area and numbers of native species, and weakly decreased with the percentage of non-native species. Weak trends were observed with latitude and negative trends with longitude. Four park groups were partitioned by cluster analysis of species relative abundance data: 7 prairie parks, 6 northern parks, 4 intermediate parks and 5 southern parks. The average percentage of non-native species was ~33% in the prairie and southern park clusters, while percentage of evergreen perennials was 2 to 4 times greater in the northern parks (8%) compared with other clusters. Deciduous perennials approached 80% in the northern and intermediate park clusters, compared with about 70% for the prairie and southern clusters. Percentage of annuals was almost double in the prairie and southern clusters (average 24%) compared with the northern and intermediate clusters (average 13%).

Illinois, Indiana, Iowa, Kansas, Michigan, Minneso↗
USGS1995

Abnormal chemical element concentrations in lichens of Isle Royale National Park

Lichens have been used for many years to monitor changes in deposited airborne chemical elements in many areas, but few studies have focused on areas suspected of experiencing slightly elevated pollution. Detection of subtle patterns of slightly elevated pollutants calls for developing several lines of evidence as opposed to single line studies used in heavily polluted areas. This study of two lichen species, Hypogymnia physodes and Evernia mesomorpha , in Isle Royale National Park, Michigan compares the concentrations and ranks of elements with the concentrations and ranks of the elements in the earth's crust, changes in element concentrations over a nine year period, and the geography of element concentrations in the park. S, Zn, Pb, Cd and Se were elevated in both species and higher in rank compared to the concentrations and ranks in the earth's crust. Toxic elements increased 123% in Hypogymnia and 62% in Evernia over 9 years, compared to increases of 45% and 59% for non-toxic elements in each species, respectively. Geographically, the lichens at certain localities with higher exposures experienced higher than average element concentrations. Finally, tissue concentrations of Mn, S and Se at some localities were above levels known to be either toxic or similar to those found in polluted areas. These four lines of evidence suggest that Isle Royale National Park is experiencing the onset of chronic air pollution stress from a number of sources.

Michigan↗