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USGS1993

Toxicity of contaminated sediments in dilution series with control sediments

T he use of dilutions has been the foundation of our approach for assessing contaminated water, and accordingly, it may be important to establish similar or parallel approaches for sediment dilutions. Test organism responses to dilution gradients can identify the degree of necessary sediment alteration to reduce the toxicity. Using whole sediment dilutions to represent the complex interactions of in situ sediments can identify the toxicity, but the selection of the appropriate diluent for the contaminated sediment may affect the results and conclusions drawn. Contaminated whole sediments were examined to evaluate the toxicity of dilutions of sediments with a diversity of test organisms. Dilutions of the contaminated sediments were prepared with differing diluents that varied in organic carbon content, particle size distribution, and volatile solids. Studies were conducted using four macroinvertebrates and a vascular, rooted plant. Responses by some test organisms followed a sigmoidal dose-response curve, but others followed a U-shaped curve. Initial dilutions reduced toxicity as expected, but further dilution resulted in an increase in toxicity. The type of diluent used was an important factor in assessing the sediment toxicity, because the control soil reduced toxicity more effectively than sand as a diluent of the same sediment. Using sediment chemical and physical characteristics as an indicator of sediment dilution may not be as useful as chemical analysis of contaminants, but warrants further investigation.

Chemosphere↗

USGS2016

Environmental controls on spatial patterns in the long-term persistence of giant kelp in central California

As marine management is moving towards the practice of protecting static areas, it is 44 important to make sure protected areas capture and protect persistent populations. Rocky reefs in 45 many temperate areas worldwide serve as habitat for canopy forming macroalgae and these 46 structure forming species of kelps (order Laminariales) often serve as important habitat for a great 47 diversity of species. Macrocystis pyrifera is the most common canopy forming kelp species found 48 along the coast of California but the distribution and abundance of M. pyrifera varies in space and 49 time. The purpose of this study is to determine what environmental parameters are correlated with 50 the spatial and temporal persistence of M. pyrifera along the central coast of California and how 51 well those environmental parameters can be used to predict areas where M. pyrifera is more likely 52 to persist. Nine environmental variables considered in this study included depth of the seafloor, 53 structure of the rocky reef, proportion of rocky reef, size of kelp patch, biomass of kelp within a 54 patch, distance from the edge of a kelp patch, sea surface temperature, wave orbital velocities, and 55 population connectivity of individual kelp patches. Using a generalized linear mixed effects model 56 (GLMM), the persistence of M. pyrifera was significantly associated with seven of the nine 57 variables considered: depth, complexity of the rocky reef, proportion of rock, patch biomass, 58 distance from the edge of a patch, population connectivity, and wave-orbital velocities. These 59 seven environmental variables were then used to predict the persistence of kelp across the central 60 coast and these predictions were compared to a reserved dataset of M. pyrifera persistence, which 61 was not used in the creation of the GLMM. The environmental variables were shown to accurately 62 predict the persistence of M. pyrifera within the central coast of California (r = 0.71, P<0.001). 63 Because persistence of giant kelp is important to the community structure of kelp forests, 64 understanding those factors that support persistent populations of M. pyrifera will enable more 65 effective management of these ecosystems.

California↗

USGS2022

A serological survey of Francisella tularensis exposure in wildlife on the Arctic Coastal Plain of Alaska

Tularemia is an infectious zoonotic disease caused by one of several subspecies of Francisella tularensis bacteria. Infections by F. tularensis are common throughout the northern hemisphere and have been detected in more than 250 wildlife species. In Alaska, US, where the pathogen was first identified in 1938, studies have identified F. tularensis antibodies in a diverse suite of taxa, including insects, birds, and mammals. However, few such investigations have been conducted recently and knowledge about the current distribution and disease ecology of F. tularensis is limited, particularly in Arctic Alaska, an area undergoing rapid environmental changes from climate warming. To help address these information gaps and provide insights about patterns of exposure among wildlife, we assessed the seroprevalence of F. tularensis antibodies in mammals and tundra-nesting geese from the Arctic Coastal Plain of Alaska, 2014–17. With a commercially available slide agglutination test, we detected antibodies in 14.7% of all individuals sampled ( n =722), with titers ranging from 1:20 to 1:320. We detected significant differences in seroprevalence between family groups, with Canidae (foxes, Vulpes spp.) and Sciuridae (Arctic ground squirrel, Spermophilus parryii ) having the highest seroprevalence at 21.5% and 33.3%, respectively. Mean seroprevalence for Ursidae (polar bears, Ursus maritimus ) was 13.3%, whereas Cervidae (caribou, Rangifer tarandus ) had comparatively low seroprevalence at 6.5%. Antibodies were detected in all Anatidae species sampled, with Black Brant ( Branta bernicla nigricans ) having the highest seroprevalence at 13.6%. The detection of F. tularensis antibodies across multiple taxa from the Arctic Coastal Plain and its nearshore marine region provides evidence of exposure to this pathogen throughout the region and highlights the need for renewed surveillance in Alaska.

Alaska↗

USGS2000

Vegetation dynamics

A disturbance can be defined as 'any relatively discrete event in time that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment' (Pickett and White 1985). Vegetation dynamics are a function of the temporal and spatial patterns of the disturbance regime. Natural disturbance regimes support the highest biological diversity; therefore, forest management practices that most closely mimic natural disturbances are expected to sustain the highest biological diversity within a given area (Denslow 1980). In southern forested wetlands, flooding is the dominant disturbance factor, thus plant species are usually distributed along a gowing-season flood gradient (Franz and Bassas 1977).

Book chapter↗

USGS2002

Sea otter studies in Glacier Bay National Park and Preserve

Following translocations to the outer coast of Southeast Alaska in 1965, sea otters have been expanding their range and increasing in abundance. We began conducting surveys for sea otters in Cross Sound, Icy Strait, and Glacier Bay, Alaska in 1994, following initial reports (in 1993) of their presence in Glacier Bay. Since 1995, the number of sea otters in Glacier Bay proper has increased from around 5 to more than 1500. Between 1993 and 1997 sea otters were apparently only occasional visitors to Glacier Bay, but in 1998 long-term residence was established as indicated by the presence of adult females and their dependent pups. Sea otter distribution is limited to the Lower Bay, south of Sandy Cove, and is not continuous within that area. Concentrations occur in the vicinity of Sita Reef and Boulder Island and between Pt. Carolus and Rush Pt. on the west side of the Bay (Figure 1). We describe the diet of sea otters during 2001 in Glacier Bay based on visual observations of prey during 456 successful forage dives. In Glacier Bay, diet consisted of 62% clam, 15% mussel, 9% crab, 7% unidentified, 4& urchins, and 4% other. Most prey recovered by sea otters are commercially, socially, or ecologically important species. Species of clam include Saxidomus gigantea, Protothaca staminea, and Mya truncata. Urchins are primarily Strongylocentrotus droebachiensis and the mussel is Modiolus modiolus. Crabs include species of three genera: Cancer, Chinoecetes, and Telmessus. Although we characterize diet at broad geographic scales, we found diet to vary between sites separated by as little as several hundred meters. Dietary variation among and within sites can reflect differences in prey availability and individual specialization. We estimated species composition, density, biomass, and sizes of subtidal clams, urchins, and mussels at 9 sites in lower Glacier Bay. All sites were selected based on the presence of abundant clam siphons. Sites were not selected to allow inference to any area larger than the sampling area (approx 400 m^2). Sites were selected to achieve a broad geographic sample of dense subtidal clam beds within Glacier Bay prior to occupation and foraging by sea otters. There was no direct evidence of otter foraging at any of our clam sampling sites. We sampled 11,568 bivalves representing 14 speces of clam and 2 species of mussel. We sampled 4,981 urchins, all Strongylocentrotus droeobachiensis. Only four species of clam (littleneck clams, Protothaca staminea; butter clams, Saxidomus gigantea; soft-shell claims, Mya truncata; and Macoma sp.) accounted for 91.6% of all clams sampled. Mean total clam density (#/0.25 m^2) across the 9 sites was 62.3. Densities (and se ) of P. staminea averaged 22.6 (1.6) and ranged from 0 to 97. Densities of S. gigantea averaged 14.4 (1.0) and ranged from 0 to 63. Densities of Macoma sp. averaged 14.5 (1.2) and ranged from 0 to 78. Densities of S. droebachiensis averaged 27.3 (1.7) and ranged from 0 to 109. Mean S. droebachiensis sizes ranged from 16 to 30 mm by site. Mean P. staminea sizes ranged from 30 to 53 mm, mean S. gigantea sizes ranged from 51 to 85 mm, and mean Macoma sp. sizes ranged from 14 to 19 mm. Although not the most abundant clam, S. gigantea contributed the greatest proportion to total clam biomass (63%), followed by P. staminea (24%). Sea otters are now well established in limited areas of the lower portions of Glacier Bay. It is likely that distribution and numbers of sea otters will continue to increase in Glacier Bay in the near future. Glacier Bay supports large and diverse populations of clams that are largely unexploited by sea otters presently. It is predictable that the density and sizes of clam populations will decline in response to otter predation. This will result in fewer opportunities for human harvest, but will also trigger ecosystem level changes, as prey for other predators, such as octopus, sea stars, fishes, birds and mammals are modified. Sea ott

Annual Report↗

USGS1971

Inland fisheries

Today's inland commercial fisheries are small independent operational units widely dispersed on lakes, impoundments, and streams throughout the vast central plains. The problems of the fisheries are diverse and unique to local conditions. Inland fisheries are particularly important to the Nation in times of international conflict because they are distributed throughout the area and the fish can be easily harvested.

Book chapter↗

USGS2011

Avian communities in tidal salt marshes of San Francisco Bay: A review of functional groups by foraging guild and habitat association

The San Francisco Bay estuary is highly urbanized, but it supports the largest remaining extent of tidal salt marshes on the west coast of North America as well as a diverse native bird community. San Francisco Bay tidal marshes are occupied by more than 113 bird species that represent 31 families, including five subspecies from three families that we denote as tidal-marsh obligates. To better identify the niche of bird species in tidal marshes, we present a review of functional groups based on foraging guilds and habitat associations. Foraging guilds describe the method by which species obtain food from tidal marshes, while habitat associations describe broad areas within the marsh that have similar environmental conditions. For example, the ubiquitous song sparrows (Alameda Melospiza melodia pusillula , Suisun M. m. maxillaris , and San Pablo M. m. samuelis ) are surface-feeding generalists that consume prey from vegetation and the ground, and they are found across the entire marsh plain into the upland–marsh transition. In contrast, surface-feeding California black rails ( Laterallus jamaicensis coturniculus ) are cryptic, and generally restricted in their distribution to the mid- and high-marsh plain. Although in the same family, the endangered California clapper rail ( Rallus longirostris obsoletus ) has become highly specialized, foraging primarily on benthic fauna within marsh channels when they are exposed at low tide. Shorebirds such as the black-necked stilt ( Himantopus mexicanus ) typically probe in mud flats to consume macroinvertebrate prey, and are generally restricted to foraging on salt pans within the marsh plain, in ponds, or on mud flats during transitional stages of marsh evolution. The abundance and distribution of birds varies widely with changing water depths and vegetation colonization during different stages of restoration. Thus, tidal-marsh birds represent a rich and diverse community in bay marshes, with niches that may be distinguished by the food resources they consume and the habitats that they occupy along the tidal gradient.

California↗

USGS2018

Survival, travel time, and utilization of Yolo Bypass, California, by outmigrating acoustic-tagged late-fall Chinook salmon

Juvenile Chinook salmon ( Oncorhynchus tshawytscha ) migrating through California's Sacramento-San Joaquin River Delta toward the Pacific Ocean face numerous challenges to their survival. The Yolo Bypass is a broad floodplain of the Sacramento River that floods in about 70 percent of years in response to large, uncontrolled runoff events. As one of the routes juvenile salmon may utilize, the Yolo Bypass has recently received attention for having potential benefit to rearing and migrating salmon. Consideration is being given to a plan to build a cut or “notch” in the Fremont Weir to increase juvenile salmon access to the Yolo Bypass. To help provide information about the potential benefit of such a plan, we analyzed data from a telemetry study conducted in February and March 2016 by the U.S. Geological Survey and California Department of Water Resources to estimate entrainment into and distribution of juvenile Chinook salmon within the Yolo Bypass, and to compare survival and travel time through the Yolo Bypass to other routes in the Delta. We also estimated juvenile Chinook salmon survival through three short reaches of the Sacramento River where the proposed California WaterFix North Delta Diversion intakes would divert water to export facilities to provide baseline information against which any effects of those intakes could be measured in the future. We found that entrainment into the Yolo Bypass varied widely and was quite high only at the peak of the March 2016 flood. Spatial distribution of juvenile Chinook salmon within the Yolo Bypass was fairly even for fish entering the Yolo Bypass over the Fremont Weir, but increasingly skewed toward the east bank for fish released within the Yolo Bypass. Survival within Yolo Bypass was not significantly different for fish based on spatial distribution. Survival through the Delta for fish migrating through the Yolo Bypass was generally on par with the weighted survival through the Delta of fish migrating through all other routes. Survival was highest for fish remaining in the Sacramento River and lowest for those entrained into the Interior Delta via Georgiana Slough. Survival through the short section of the Sacramento River near the proposed North Delta Diversion intakes was high.

California↗

USGS2004

Characterization of ichthyoplankton within the U.S. Geological Survey's Northeastern Gulf of Mexico study area - based on analysis of Southeast Area Monitoring and Assessment Program (SEAMAP) Sampling Surveys, 1982-1999. NEGOM ichthyoplankton synopsis final report

This synthesis was undertaken to characterize the occurrence and abundance of fish eggs and larvae in the northeastern Gulf of Mexico (NEGOM) and to assess the region's relative importance in the early life history of fishes as compared to the entire U.S. Gulf of Mexico. Data for 66 selected taxa from 1,166 bongo and neuston net samples at 72 localities [comprising the UGSG NEGOM Ichthyoplankton Synopsis (UNIS) Study Area] were analyzed. These data were taken during annual Southeast Area Monitoring and Assessment Program (SEAMAP) gulfwide surveys from 1982-1999, and were summarized by the NMFS to accomplish this objective. Comparison of the UNIS Study Area with the overall SEAMAP survey area revealed that the larvae of 16 taxa occurred more frequently and were relatively more abundant in the UNIS Study Area than the entire SEAMAP survey area while for other taxa occurrence and relative abundance were comparable. These taxa represented fishes from mesopelagic, continental shelf, and reef assemblages reflecting the wide diversity of habitats available in the NEGOM and included the young of two important resource taxa, Rhomboplites aurorubens (vermilion snapper) and Seriola spp. (amberjacks). Distinct distribution patterns were observed among larvae in the UNIS Study Area that appear to be associated with the presence of the DeSoto Canyon. One notable pattern was the predominance of certain taxa to either the west or east of longitude 86.5-87.0o W. Larvae of several characteristic reef-fish families were most common to the east of this apparent zoogeographic faunal discontinuity. An alternative pattern was seen among taxa whose larvae occurred primarily at locations over depth contours outlining the canyon. Additionally, the UNIS Study Area contributed more fish eggs, total larvae, and zooplankton to survey totals than would be expected from the number of samples taken in the study area. This pattern was more evident during spring than fall surveys. It may relate to the close proximity of UNIS Study Area stations to the Mississippi River and the penetration of DeSoto Canyon, with its nutrient-rich deep slope water, into the inner shelf. The consistent presence of fish eggs throughout the NEGOM at mean abundances exceeding 100 eggs per 10 m? sea surface indicates that this region of the Gulf of Mexico is an important spawning area. The present synopsis has revealed that the NEGOM, as represented by the UNIS Study Area, should be considered an important, if not critical, habitat for the young stages of a diverse assemblage of fish taxa. The greatest biological deficiency in this synopsis is our current inability to identify the larvae of all species to a consistent taxonomic level.

Scientific Investigations Report↗

USGS1986

Benthic invertebrate population characteristics as affected by water quality in coal-bearing regions of Tennessee

Benthic invertebrate and water quality data collected during previous U.S. Geological Survey studies to provide background hydrologic information on streams draining Tennessee coal reserves, were evaluated to identify possible relations between stream biota and water quality. Linear regressions produced low correlation coefficients relating the number of taxa/sample, total number of organisms/sample, sample diversity, and percentage composition of selected orders of invertebrates, with average water quality parameter values available at sampling stations (r is < 0.62 at p=0.05). Analyses of these data by linear regressions explained little of the variability in benthic invertebrate samples primarily because the distributions of benthic organisms along environmental gradients are nonlinear. Variability in substrate characteristics in the study area and seasonal insect emergence patterns also complicated interpretation of these data. However, analysis of variance tests did indicate significant trends towards reduced number of taxa, number of organisms, and sample diversity at stations with relatively poor water quality conditions. Decreasing percentage composition of Ephemeroptera was generally accompanied by an increase in percent Diptera at stations with higher water quality constituent concentrations and acidic pH (> than 0.6 units). These trends indicate significant differences in benthic communities at sites with evidence of more severe land use impacts. Additional data on benthic invertebrates, water quality, and physical habitat conditions, along with analyses of data using multivariate statistical methods are needed to define ecological relations between specific groups of invertebrates and environmental conditions.

Tennessee↗

USGS2020

Combining genetic and demographic monitoring better informs conservation of an endangered urban snake

Conversion and fragmentation of wildlife habitat often leads to smaller and isolated populations and can reduce a species’ ability to disperse across the landscape. As a consequence, genetic drift can quickly lower genetic variation and increase vulnerability to extirpation. For species of conservation concern, quantification of population size and connectivity can clarify the influence of genetic drift in local populations and provides important information for conservation management and recovery strategies. Here, we used genome-wide single nucleotide polymorphism (SNP) data and capture-mark-recapture methods to evaluate the genetic diversity and demography within seven focal sites of the endangered San Francisco gartersnake ( Thamnophis sirtalis tetrataenia ), a species affected by alteration and isolation of wetland habitats throughout its distribution. The primary goals were to determine the population structure and degree of genetic isolation among T . s . tetrataenia populations and estimate effective size and population abundance within sites to better understand the present and future importance of genetic drift. We also used temporally sampled datasets to examine the magnitude of genetic change over time. We found moderate population genetic structure throughout the San Francisco Peninsula that partitions sites into northern and southern regional clusters. Point estimates of both effective size and population abundance were generally small (≤ 100) for a majority of the sites, and estimates were particularly low in the northern populations. Genetic analyses of temporal datasets indicated an increase in genetic differentiation, especially for the most geographically isolated sites, and decreased genetic diversity over time in at least one site (Pacifica). Our results suggest that drift-mediated processes as a function of small population size and reduced connectivity from neighboring populations may decrease diversity and increase differentiation. Improving genetic diversity and connectivity among T . s . tetrataenia populations could promote persistence of this endangered snake.

California↗

USGS2014

Life history strategies of fish species and biodiversity in eastern USA streams

Predictive models have been used to determine fish species that occur less frequently than expected (decreasers) and those that occur more frequently than expected (increasers) in streams in the eastern U.S. Coupling life history traits with 51 decreaser and 38 increaser fish species provided the opportunity to examine potential mechanisms associated with predicted changes in fish species distributions in eastern streams. We assigned six life history traits – fecundity, longevity, maturation age, maximum total length, parental care, and spawning season duration – to each fish species. Decreaser species were significantly smaller in size and shorter-lived with reduced fecundity and shorter spawning seasons compared to increaser species. Cluster analysis of traits revealed correspondence with a life history model defining equilibrium (low fecundity, high parental care), opportunistic (early maturation, low parental care), and periodic (late maturation, high fecundity, low parental care) end-point strategies. Nearly 50 % of decreaser species were associated with an intermediate opportunistic-periodic strategy, suggesting that abiotic factors such as habitat specialization and streamflow alteration may serve as important influences on life history traits and strategies of decreaser species. In contrast, the percent of increaser species among life history strategy groups ranged from 21 to 32 %, suggesting that life history strategies of increaser species were more diverse than those of decreaser species. This study highlights the utility of linking life history theory to biodiversity to better understand mechanisms that contribute to fish species distributions in the eastern U.S.

Environmental Biology of Fishes↗

USGS2001

Potential changes in the distributions of western North America tree and shrub taxa under future climate scenarios

Increases in atmospheric greenhouse gases are driving significant changes in global climate. To project potential vegetation response to future climate change, this study uses response surfaces to describe the relationship between bioclimatic variables and the distribution of tree and shrub taxa in western North America. The response surfaces illustrate the probability of the occurrence of a taxon at particular points in climate space. Climate space was defined using three bioclimatic variables: mean temperature of the coldest month, growing degree days, and a moisture index. Species distributions were simulated under present climate using observed data (1951–80, 30-year mean) and under future climate (2090–99, 10-year mean) using scenarios generated by three general circulation models—HADCM2, CGCM1, and CSIRO. The scenarios assume a 1% per year compound increase in greenhouse gases and changes in sulfate (SO 4 ) aerosols based on the Intergovernmental Panel on Climate Change (IPCC) IS92a scenario. The results indicate that under future climate conditions, potential range changes could be large for many tree and shrub taxa. Shifts in the potential ranges of species are simulated to occur not only northward but in all directions, including southward of the existing ranges of certain species. The simulated potential distributions of some species become increasingly fragmented under the future climate scenarios, while the simulated potential distributions of other species expand. The magnitudes of the simulated range changes imply significant impacts to ecosystems and shifts in patterns of species diversity in western North America.

Ecosystems↗

USGS2014

Songbirds as sentinels of mercury in terrestrial habitats of eastern North America

Mercury (Hg) is a globally distributed environmental contaminant with a variety of deleterious effects in fish, wildlife, and humans. Breeding songbirds may be useful sentinels for Hg across diverse habitats because they can be effectively sampled, have well-defined and small territories, and can integrate pollutant exposure over time and space. We analyzed blood total Hg concentrations from 8,446 individuals of 102 species of songbirds, sampled on their breeding territories across 161 sites in eastern North America [geometric mean Hg concentration = 0.25 μg/g wet weight (ww), range <0.01–14.60 μg/g ww]. Our records span an important time period—the decade leading up to implementation of the USEPA Mercury and Air Toxics Standards, which will reduce Hg emissions from coal-fired power plants by over 90 %. Mixed-effects modeling indicated that habitat, foraging guild, and age were important predictors of blood Hg concentrations across species and sites. Blood Hg concentrations in adult invertebrate-eating songbirds were consistently higher in wetland habitats (freshwater or estuarine) than upland forests. Generally, adults exhibited higher blood Hg concentrations than juveniles within each habitat type. We used model results to examine species-specific differences in blood Hg concentrations during this time period, identifying potential Hg sentinels in each region and habitat type. Our results present the most comprehensive assessment of blood Hg concentrations in eastern songbirds to date, and thereby provide a valuable framework for designing and evaluating risk assessment schemes using sentinel songbird species in the time after implementation of the new atmospheric Hg standards.

Ecotoxicology↗

USGS2020

Sediment dynamics of a divergent bay–marsh complex

Bay–marsh systems, composed of an embayment surrounded by fringing marsh incised by tidal channels, are widely distributed coastal environments. External sediment availability, marsh-edge erosion, and sea-level rise acting on such bay–marsh complexes may drive diverse sediment-flux regimes. These factors reinforce the ephemeral and dynamic nature of fringing marshes: material released by marsh-edge erosion becomes part of a bay–marsh exchange that fuels the geomorphic evolution of the coupled system. The dynamics of this sediment exchange determine the balance among seaward export, deposition on the embayment seabed, flux into tidal channels, and import to the marsh platform. In this work, we investigate the sediment dynamics of a transgressive bay–marsh complex and link them to larger-scale considerations of its geomorphic trajectory. Grand Bay, Alabama/Mississippi, is a shallow microtidal embayment surrounded by salt marshes with lateral erosion rates of up to 5 m year −1 . We collected 6 months of oceanographic data at four moorings within Grand Bay and its tidal channels to assess hydrographic conditions and net sediment-flux patterns and augmented the observations with numerical modeling. The observations imply a divergent sedimentary system in which a majority of the suspended sediment is exported seaward, while a smaller fraction is imported landward via tidal channels, assisting in vertical marsh-plain accumulation, maintenance of channel and intertidal-flat morphologies, and landward transgression. These results describe a dynamic system that is responsive to episodic atmospheric forcing in the absence of a strong tidal signal and the presence of severe lateral marsh loss.

Alabama, Mississippi↗

USGS1998

Benthic-invertebrate and streambed-sediment data for the White River and its tributaries in and near Indianapolis, Indiana, 1994–96

Data were collected in the White River and its tributaries in and near Indianapolis, Indiana, on the diversity and density of benthic invertebrates; concentrations of metals, insecticides, herbicides, and semivolatile organic compounds sorbed on streambed sediments; and particle-size distribution of streambed sediments. A total of 369 benthic-invertebrate samples were collected at 21 sites during late spring or summer and early fall 1994 through 1996; of these, 30 were quality-control samples. A total of 33 streambed-sediment samples were collected at 14 sites during August 1994, 1995, and 1996; of these, 10 were quality-control samples.

Indiana↗

USGS1980

Ordovician and Silurian Phi Kappa and Trail Creek formations, Pioneer Mountains, central Idaho: Stratigraphic and structural revisions, and new data on graptolite faunas

Recent geologic mapping in the northern Pioneer Mountains combined with the identification of graptolites from 116 new collections indicate that the Ordovician and Silurian Phi Kappa and Trail Creek Formations occur in a series of thrust-bounded slices within a broad zone of imbricate thrust faulting. Though confirming a deformational style first reported in a 1963 study by Michael Churkin, our data suggest that the complexity and regional extent of the thrust zone were not previously recognized. Most previously published sections of the Phi Kappa and Trail Creek Formations were measured across unrecognized thrust faults and therefore include not only structural repetitions of graptolitic Ordovician and Silurian rocks but also other tectonically juxtaposed lithostratigraphic units of diverse ages as well. Because of this discovery, the need to reconsider the stratigraphic validity of these formations and their lithology, nomenclature, structural distribution, facies relations, and graptolite faunas has arisen. The Phi Kappa Formation in most thrust slices has internal stratigraphic continuity despite the intensity of deformation to which it was subjected. As revised herein, the Phi Kappa Formation is restricted to a structurally repeated succession of predominantly black, carbonaceous, graptolitic argillite and shale. Some limy, light-gray-weathering shale occurs in the middle part of the section, and fine-grained locally pebbly quartzite is present at the base. The basal quartzite is here named the Basin Gulch Quartzite Member of the Phi Kappa. The Phi Kappa redefined on a lithologic basis represents the span of Ordovician time from W. B. N. Berry's graptolite zones 2-4 through 15 and also includes approximately 17 m of lithologically identical shale of Early and Middle Silurian age at the top. The lower contact of the formation as revised is tectonic. The Phi Kappa is gradationally overlain by the Trail Creek Formation as restricted herein. Most of the coarser clastic rocks reported in previously measured sections of the Phi Kappa, as well as the sequence along Phi Kappa Creek from which the name originates, are excluded from the Phi Kappa as revised and are reassigned to two structural plates of Mississippian Copper Basin Formation; other strata now excluded from the formation are reassigned to the Trail Creek Formation and to an unnamed Silurian and Devonian unit. As redefined, the Phi Kappa Formation is only about 240 m thick, compared with the 3,860 m originally estimated, and it occupies only about 25 percent of the outcrop area previously mapped in 1930 by H. G. Westgate and C. P. Ross. Despite this drastic reduction in thickness and the exclusion of the rocks along Phi Kappa Creek, the name Phi Kappa is retained because of widely accepted prior usage to denote the Ordovician graptolitic shale facies of central Idaho, and because the Phi Kappa Formation as revised is present in thrust slices on Phi Kappa Mountain, at the head of Phi Kappa Creek. The lithic and faunal consistency of this unit throughout the area precludes the necessity for major facies telescoping along individual faults within the outcrop belt. However, tens of kilometers of tectonic shortening seems required to juxtapose the imbricated Phi Kappa shale facies with the Middle Ordovician part of the carbonate and quartzite shale sequence of east central Idaho. The shelf rocks are exposed in the Wildhorse structural window of the northeastern Pioneer Mountains, and attain a thickness of at least 1,500 m throughout the region north and east of the Pioneer Mountains. The Phi Kappa is in direct thrust contact on intensely deformed medium- to high-grade metamorphic equivalents of the same shelf sequence in the Pioneer window at the south end of the Phi Kappa-Trail Creek outcrop belt. Along East Pass, Big Lake, and Pine Creeks, north of the Pioneer Mountains, some rocks previously mapped as Ramshorn Slate are lithologically and faunally equivalent to the P

Idaho↗

USGS2013

Field trial of a pulsed limestone diversion well

The use of limestone diversion wells to treat acid mine drainage (AMD) is well-known, but in many cases, acid neutralization is not as complete as would be desired. Reasons for this include channeling of the water through the limestone bed, and the slow reaction rate of the limestone gravel. A new approach to improve the performance of the diversion well was tested in the field at the Jennings Environmental Education Center, near Slippery Rock, PA. In this approach, a finer size distribution of limestone was used so as to allow fluidization of the limestone bed, thus eliminating channeling and increasing particle surface area for faster reaction rates. Also, water flow was regulated through the use of a dosing siphon, so that consistent fluidization of the limestone sand could be achieved. Testing began late in the summer of 2010, and continued through November of 2011. Initial system performance during the 2010 field season was good, with the production of net alkaline water, but hydraulic problems involving air release and limestone sand retention were observed. In the summer of 2011, a finer size of limestone sand was procured for use in the system. This material fluidized more readily, but acid neutralization tapered off after several days. Subsequent observations indicated that the hydraulics of the system was compromised by the formation of iron oxides in the pipe leading to the limestone bed, which affected water distribution and flow through the bed. Although results from the field trial were mixed, it is believed that without the formation of iron oxides and plugging of the pipe, better acid neutralization and treatment would have occurred. Further tests are being considered using a different hydraulic configuration for the limestone sand fluidized bed.

Pennsylvania↗