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At least 361 records · Page 20Linked to original sources
USGS2000

Genetic analyses reveal unusually high diversity of infectious haematopoietic necrosis virus in rainbow trout aquaculture

Infectious haematopoietic necrosis virus (IHNV) is the most significant virus pathogen of salmon and trout in North America. Previous studies have shown relatively low genetic diversity of IHNV within large geographical regions. In this study, the genetic heterogeneity of 84 IHNV isolates sampled from rainbow trout ( Oncorhynchus mykiss ) over a 20 year period at four aquaculture facilities within a 12 mile stretch of the Snake River in Idaho, USA was investigated. The virus isolates were characterized using an RNase protection assay (RPA) and nucleotide sequence analyses. Among the 84 isolates analysed, 46 RPA haplotypes were found and analyses revealed a high level of genetic heterogeneity relative to that detected in other regions. Sequence analyses revealed up to 7·6% nucleotide divergence, which is the highest level of diversity reported for IHNV to date. Phylogenetic analyses identified four distinct monophyletic clades representing four virus lineages. These lineages were distributed across facilities, and individual facilities contained multiple lineages. These results suggest that co-circulating IHNV lineages of relatively high genetic diversity are present in the IHNV populations in this rainbow trout culture study site. Three of the four lineages exhibited temporal trends consistent with rapid evolution.

Journal of General Virology↗
USGS2006

Effects of Surface-Water Diversion and Ground-Water Withdrawal on Streamflow and Habitat, Punaluu Stream, Oahu, Hawaii

The surface- and ground-water resources of the Punaluu area of northeast Oahu, Hawaii, have been and continue to be important for cultural, domestic, agricultural, recreational, and aesthetic purposes. Punaluu Stream flows perennially because rain falls frequently in the area and ground water discharges to the stream. Flow in Punaluu Stream is reduced by the direct diversion of water for off-stream uses and possibly from the withdrawal of ground water near the stream. Punaluu Ditch diverts water from Punaluu Stream near an altitude of 210 feet. During the recent period 1995-2004, discharge in Punaluu Stream that was equaled or exceeded 50 percent of the time (median or Q50 discharge) and discharge that was equaled or exceeded 95 percent of the time (Q95 discharge) measured immediately upstream from the Punaluu Ditch diversion intake, respectively, were 18 and 13 cubic feet per second, whereas the Q50 and Q95 discharges measured immediately downstream from the diversion intake, respectively, were 7.0 and 1.3 cubic feet per second. Thus, near an altitude of 210 feet, diversion of surface water by the Punaluu Ditch caused the Q50 discharge in Punaluu Stream to be reduced to 39 percent of the natural Q50 discharge, and the Q95 discharge was reduced to 10 percent of the natural value. The relative effects of the Punaluu Ditch diversion on flow in Punaluu Stream decreased in a downstream direction, mainly because of the compensating effects of tributary inflows and ditch return flows. At an altitude of 10 feet, the Q50 discharge in Punaluu Stream was 82 percent of the natural Q50 discharge, and the Q95 discharge was 69 percent of the natural value. Changes in streamflow affect the quantity and quality of physical habitat used by native stream fauna. The Physical Habitat Simulation System (PHABSIM) approach was used to evaluate the effects of different diversion scenarios on physical habitat for selected native species in Punaluu Stream. Habitat-suitability criteria developed for streams in northeast Maui, Hawaii, were used to determine the effects of incremental changes in streamflow on physical habitat, in terms of weighted usable area (WUA) in Punaluu Stream. The effects of different diversion conditions on WUA for Neritina granosa and Awaous guamensis were evaluated by determining the average number of days per year for which WUA values are less than a specified reference value (during periods when discharge is less than or equal to the median natural discharge). For recent diverted conditions (1995-2004), the average number of days per year that WUA values are less than 50 or 75 percent of the WUA value at median natural discharge generally (1) decreases in a downstream direction, reflecting the effects of tributary inflows and ditch return flows, (2) is less than the corresponding number of days for constant diversion rates greater than about 4-5 cubic feet per second at a stream altitude of 10 feet, and (3) is greater than the corresponding number of days for a constant diversion rate of 10 cubic feet per second at stream altitudes of 40, 100, and 140 feet. The number of days that WUA values are less than 75 percent of the WUA value at median natural discharge generally increases substantially for constant diversion rates exceeding about 4-5 cubic feet per second. At stream altitudes of 10, 40, 100, and 200 feet and for constant diversion rates of up to 4 cubic feet per second, WUA values are less than 75 percent of the WUA value at median natural discharge for fewer than 13 days per year. At stream altitudes above 40 feet and for a constant diversion rate of 10 cubic feet per second, WUA values are less than 75 percent of the WUA value at median natural discharge for 131 to 183 days per year. Stream temperature is a factor that potentially could affect the abundance and distribution of native aquatic species. Measured stream temperatures immediately upstream and downstream from the diversion intake did not indicat

Scientific Investigations Report↗
USGS2024

Disentangling genetic diversity of Myotis septentrionalis: population structure, demographic history, and effective population size

Myotis septentrionalis (Northern Long-eared Bat) has recently suffered a >90% decline in population size in North America due to white-nose syndrome (WNS). We assessed genetic diversity, population structure, current effective population size, and demographic history of M. septentrionalis distributed across the United States to determine baseline levels pre-WNS. We analyzed RADseq data from 81 individuals from Kentucky, Louisiana, Michigan, Minnesota, North Carolina, Oklahoma, and Wisconsin. Additionally, we examined population genetic structure using discriminant analysis of principal components, fastStructure, and STRUCTURE. We then estimated effective population size and demographic history using fastsimcoal2. Similar levels of genetic diversity were found across all samples. We found no population genetic structure in the varied analyses from these contemporary samples. The best model for demographic history estimated a rapid population expansion followed by a slower expansion approximately 340,000 years ago. The vagility of M. septentrionalis , along with male dispersal and random mating, may provide a buffer against serious bottleneck effects stemming from rapid population declines due to WNS. This research provides a baseline for tracking and monitoring the influence of WNS on genetic diversity such as potential reduced diversity or increased population structuring in the future.

Kentucky, Louisiana, Michigan, Minnesota, North Ca↗
USGS2022

Avian-associated Aspergillus fumigatus displays broad phylogenetic distribution, no evidence for host specificity, and multiple genotypes within epizootic events

Birds are highly susceptible to aspergillosis, which can manifest as a primary infection in both domestic and wild birds. Aspergillosis in wild birds causes mortalities ranging in scale from single animals to large-scale epizootic events. However, pathogenicity factors associated with aspergillosis in wild birds have not been examined. Specifically, it is unknown whether wild bird-infecting strains are host-adapted (i.e. phylogenetically related). Similarly, it is unknown whether epizootics are driven by contact with clonal strains that possess unique pathogenic or virulence properties, or by distinct and equally pathogenic strains. Here, we use a diverse collection of Aspergillus fumigatus isolates taken from aspergillosis-associated avian carcasses, representing 24 bird species from a wide geographic range, and representing individual bird mortalities as well as epizootic events. These isolates were sequenced and analyzed along with 130 phylogenetically diverse human clinical isolates to investigate the genetic diversity and phylogenetic placement of avian-associated A. fumigatus , the geographic and host distribution of avian isolates, evidence for clonal outbreaks among wild birds, and the frequency of azole resistance in avian isolates. We found that avian isolates were phylogenetically diverse, with no clear distinction from human clinical isolates, and no sign of host or geographic specificity. Avian isolates from the same epizootic events were diverse and phylogenetically distant, suggesting that avian aspergillosis is not contagious among wild birds and that outbreaks are likely driven by environmental spore loads or host comorbidities. Finally, all avian isolates were susceptible to Voriconazole and none contained the canonical azole resistance gene variants.

G3 Genes|Genomes|Genetics↗
USGS2007

Surficial sediment character of the New York-New Jersey offshore continental shelf region: A GIS compilation

Broad continental shelf regions such as the New York Bight are the product of a complex geologic history and dynamic oceanographic processes, dominated by the Holocene marine transgression (>100 m sea-level rise) following the end of the last Pleistocene ice advance ~ 20,000 years ago. The area of the U.S. Exclusive Economic Zone (U.S. EEZ) territory, extending 200 nautical miles seaward from the coast, is larger than the continental U.S. and contains submerged landforms that provide a variety of natural functions and societal benefits, such as: critical habitats for fisheries, ship navigation and homeland security, and engineering activities (i.e. oil and gas platforms, pipeline and cable routes, potential wind-energy-generation sites). Some parts of the continental margins, particularly inner-continental shelf regions, also contain unconsolidated hard-mineral deposits such as sand and gravel that are regarded as potential aggregate resources to meet or augment needs not met by onshore deposits (Williams, 1992). The present distribution of surficial sediment off the northeastern United States is shaped from the deposits left by the last glaciation and reflects the cumulative effects of sediment erosion, transport, sorting, and deposition by storm and tidal processes during the Holocene rise in sea level. As a result, the sediments on the sea floor represent both an historical record of former conditions and a guide to possible future sedimentary environments. The U.S. Geological Survey (USGS) through the Coastal and Marine Geology Program, in cooperation with the University of Colorado and other partners, has compiled extant sediment character and textural data as well as other geologic information on the sea floor from all regions around the U.S. into the usSEABED data system (Reid and others, 2005; Buczkowski and others, 2006; Reid and others, 2006). The usSEABED system, which contains information on sediment grain size and lithology for more than 340,500 stations within the U.S. EEZ. has been developed and populated with data as part of the USGS Marine Aggregate Resources and Processes and the National Benthic Habitats projects in order to provide the base-line data needed to update the current maps of offshore surficial geologic character and sediment distribution. The maps are also used to characterize benthic sea floor environments important for marine ecosystems. U.S. Geological Survey, Data Series 118 (Reid and others, 2005), of the usSEABED data release series, represents the combined efforts of the USGS and several other government agencies to provide a unified resource for accessing and preserving records of U.S. east coast sea floor geologic information and sediment texture data. For this present report, we have chosen to focus on the New York-New Jersey region, an area that has been intensely studied by the USGS for many years to address many complex issues. This report illustrates the uses of the usSEABED database for GIS applications, while offering additional insight into the resources and data available from the USGS and its collaborative institutions. This report is based on data contained in U.S. Geological Survey Data Series 118 (Reid and others, 2005) and shows an assortment of example GIS products that are possible using usSEABED. All data are intended to be GIS-ready and should not require any additional cleanup, formatting, or renaming of fields in order to use the data in a Geographic Information System. This project employs the Environmental Systems Research Institute's (ESRI) ArcView™ software. Many of these maps were made as part of the ongoing USGS study to assess marine aggregate resources offshore New York and New Jersey, but these maps can serve many other purposes. The marine science community, educators, students and others are encouraged to use these data to generate GIS products for their own purposes. The objectives of the Marine Aggregate Resources and Processes project are to produce a series of new geologic maps and reports of the sea floor that will provide scientific insights into the character and geologic development of U.S. continental margins and to use these maps and information to assess the potential availability of offshore sand and gravel resources. The mapping and aggregate resource assessments are being conducted on a national scale using the usSEABED data base as described in Williams and others (2003). Potential uses for these data include: (1) defining the geological variability of the sea floor in relation to benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and benthic habitats; (3) locating aggregate resources for beach nourishment and industrial applications; and (4) providing a detailed geospatial framework for future marine science research, monitoring, and management activities. The initial assessments are in progress for the New York Bight and Louisiana offshore areas.

New Jersey, New York↗
USGS2017

Simulation of groundwater and surface-water flow in the upper Deschutes Basin, Oregon

This report describes a hydrologic model for the upper Deschutes Basin in central Oregon developed using the U.S. Geological Survey (USGS) integrated Groundwater and Surface-Water Flow model (GSFLOW). The upper Deschutes Basin, which drains much of the eastern side of the Cascade Range in Oregon, is underlain by large areas of permeable volcanic rock. That permeability, in combination with the large annual precipitation at high elevations, results in a substantial regional aquifer system and a stream system that is heavily groundwater dominated. The upper Deschutes Basin is also an area of expanding population and increasing water demand for public supply and agriculture. Surface water was largely developed for agricultural use by the mid-20th century, and is closed to additional appropriations. Consequently, water users look to groundwater to satisfy the growing demand. The well‑documented connection between groundwater and the stream system, and the institutional and legal restrictions on streamflow depletion by wells, resulted in the Oregon Water Resources Department (OWRD) instituting a process whereby additional groundwater pumping can be permitted only if the effects to streams are mitigated, for example, by reducing permitted surface-water diversions. Implementing such a program requires understanding of the spatial and temporal distribution of effects to streams from groundwater pumping. A groundwater model developed in the early 2000s by the USGS and OWRD has been used to provide insights into the distribution of streamflow depletion by wells, but lacks spatial resolution in sensitive headwaters and spring areas. The integrated model developed for this project, based largely on the earlier model, has a much finer grid spacing allowing resolution of sensitive headwater streams and important spring areas, and simulates a more complete set of surface processes as well as runoff and groundwater flow. In addition, the integrated model includes improved representation of subsurface geology and explicitly simulates the effects of hydrologically important fault zones not included in the previous model. The upper Deschutes Basin GSFLOW model was calibrated using an iterative trial and error approach using measured water-level elevations (water levels) from 800 wells, 144 of which have time series of 10 or more measurements. Streamflow was calibrated using data from 21 gage locations. At 14 locations where measured flows are heavily influenced by reservoir operations and irrigation diversions, so called “ naturalized ” flows, with the effects of reservoirs and diversion removed, developed by the Bureau of Reclamation, were used for calibration. Surface energy and moisture processes such as solar radiation, snow accumulation and melting, and evapotranspiration were calibrated using national datasets as well as data from long-term measurement sites in the basin. The calibrated Deschutes GSFLOW model requires daily precipitation, minimum and maximum air temperature data, and monthly data describing groundwater pumping and artificial recharge from leaking irrigation canals (which are a significant source of groundwater recharge). The calibrated model simulates the geographic distribution of hydraulic head over the 5,000 ft range measured in the basin, with a median absolute residual of about 53 ft. Temporal variations in head resulting from climate cycles, pumping, and canal leakage are well simulated over the model area. Simulated daily streamflow matches gaged flows or calculated naturalized flows for streams including the Crooked and Metolius Rivers, and lower parts of the mainstem Deschutes River. Seasonal patterns of runoff are less well fit in some upper basin streams. Annual water balances of streamflow are good over most of the model domain. Model fit and overall capabilities are appropriate for the objectives of the project. The integrated model results confirm findings from other studies and models indicating that most streamflow in the upper Deschutes Basin comes directly from groundwater discharge. The integrated model provides additional insights about the components of streamflow including direct groundwater discharge to streams, interflow, groundwater discharge to the land surface (Dunnian flow), and direct runoff (Hortonian flow). The new model provides improved capability for exploring the timing and distribution of streamflow capture by wells, and the hydrologic response to changes in other external stresses such as canal operation, irrigation, and drought. Because the model uses basic meteorological data as the primary input; and simulates surface energy and moisture balances, groundwater recharge and flow, and all components of streamflow; it is well suited for exploring the hydrologic response to climate change, although no such simulations are included in this report. The model was developed as a tool for future application; however, example simulations are provided in this report. In the example simulations, the model is used to explore the influence of well location and geologic structure on stream capture by pumping wells. Wells were simulated at three locations within a 12-mi area close to known groundwater discharge areas and crossed by a regional fault zone. Simulations indicate that the magnitude and timing of stream capture from pumping is largely controlled by the geographic location of the wells, but that faults can have a large influence on the propagation of pumping stresses.

Oregon↗
USGS2010

Geomorphology of mesophotic coral ecosystems: Current perspectives on morphology, distribution, and mapping strategies

This paper presents a general review of the distribution of mesophotic coral ecosystems (MCEs) in relationship to geomorphology in US waters. It was specifically concerned with the depth range of 30–100 m, where more than 186,000 km2 of potential seafloor area was identified within the US Gulf of Mexico/Florida, Caribbean, and main Hawaiian Islands. The geomorphology of MCEs was largely inherited from a variety of pre-existing structures of highly diverse origins, which, in combination with environmental stress and physical controls, restrict the distribution of MCEs. Sea-level history, along with depositional and erosional processes, played an integral role in formation of MCE settings. However, mapping the distribution of both potential MCE topography/substrate and existing MCE habitat is only beginning. Mapping techniques pertinent to understanding morphology and MCE distributions are discussed throughout this paper. Future investigations need to consider more cost-effective and remote methods (such as autonomous underwater vehicles (AUVs) and acoustics) in order to assess the distribution and extent of MCE habitat. Some understanding of the history of known MCEs through coring studies would help understand their initiation and response to environmental change over time, essential for assessing how they may be impacted by future environmental change.

Alabama, Florida, Georgia, Hawai'i, Louisiana, Mis↗
USGS2022

Decades of global sturgeon conservation efforts are threatened by an expanding captive culture industry

After centuries of overexploitation and habitat loss, many of the world's sturgeon (Acipenseridae) populations are at the brink of extinction. Although significant resources are invested into the conservation and restoration of imperiled sturgeons, the burgeoning commercial culture industry poses an imminent threat to the persistence of many populations. In the past decade, the number and distribution of captive sturgeon facilities has grown exponentially and now encompasses diverse interest groups ranging from hobby aquarists to industrial-scale commercial facilities. Expansion of sturgeon captive culture has largely fallen outside the purview of existing regulatory frameworks, raising concerns that continued growth of this industry has real potential to jeopardize conservation of global sturgeon populations. Here, we highlight some of the most significant threats commercial culture poses to wild populations, with particular emphasis on how releases can accelerate wild population declines through mechanisms such as hybridization, introgression, competition, and disease transmission. We also note that in some circumstances, commercial captive culture has continued to motivate harvest of wild populations, potentially accelerating species' declines. Given the prevalence and trajectory of sturgeon captive culture programs, we comment on modifications to regulatory frameworks that could improve the ability of captive culture to support wild sturgeon conservation.

Fisheries Magazine↗
USGS2014

Regional differentiation among populations of the Diamondback terrapin ( Malaclemys terrapin )

The Diamondback terrapin (Malaclemys terrapin) is a brackish-water turtle species whose populations have been fragmented due to anthropogenic activity such as development of coastal habitat and entrapment in commercial blue crab (Callinectes sapidus) fishing gear. Genetic analyses can improve conservation efforts for the long-term protection of the species. We used microsatellite DNA analysis to investigate levels of gene flow among and genetic variability within 21 geographically separate collections of the species distributed from Massachusetts to Texas. Quantified levels of genetic variability (allelic diversity, genotypic frequencies, and heterozygosity) revealed three zones of genetic discontinuity, resulting in four discrete populations: Northeast Atlantic, Coastal Mid-Atlantic, Florida and Texas/Louisiana. The average number of alleles and expected heterozygosity for the four genetic clusters were N A = 6.54 and H E = 0.050, respectively. However, the geographic boundaries of the populations did not correspond to accepted terrapin subspecies limits. Our results illuminate not only the need to sample terrapins in additional sites, specifically in the southeast, but also the necessity for allowing uninterrupted gene flow among population groupings to preserve current levels of genetic diversity.

Conservation Genetics↗
USGS1988

Paleoecology of Middle Pennsylvanian-age peat-swamp plants in Herrin coal, Kentucky, U.S.A.

To develop a method for quantifying the vegetation of Pennsylvania-age coal beds, of four coal-ball (permineralized peat) profiles and four coal column samples from the Herrin coal bed (Kentucky No. 11) Carbondale Formation in western Kentucky were compared. An estimated 89.5% of the coal can be identified botanically. Compaction ratios for individual tissues were estimated using point counts of organic matter in coal balls. The estimated abundances of major plant groups (lycopods, ferns, sphenopsids, and pteridosperms) in coal balls differ by less than 10% compared to coal after accounting for differential compaction of plant tissues. Standard deviations in taxonomic and maceral composition among coal columns are generally less than 2%. Consistent differences in botanical composition were found between benches showing that the method is consistent when applied to sufficient thicknesses of coal. It was not possible to make fine-scale correlations within the coal bed using the vegetational data; either the flora varied considerably from place to place or the method of quantification is unreliable for small increments of coal (5 cm or less). In the coal, pteridosperm abundance is positively correlated with underlying shale partings. This correlation suggests that pteridosperms are favored either by higher nutrient levels or disturbance. In the third of four benches in the Herrin coal bed, a succession from Sigillaria -containing zones to zones dominated by Lepidophloios hallii is interpreted as a shift towards wetter conditions. In the other benches, the main factors controlling the taxonomic composition appear to have been the relative abundance of nutrients and/or the frequency of disturbance as indicated by the relative abundance of partings. Criteria for distinguishing between domed and planar swamps are discussed. These include: distribution of partings, type of plant succession, and changes in plant diversity, average plant size, preservational quality and sporinite content. The infrequency of partings in bench C suggests a peat dome developed while the peat of that bench was accumulating but other evidence either fails to support the development of a peat dome or is ambiguous. The maceral composition resembles those of other Carboniferous coals which are thought to have formed from planar peat swamps. Formation of fusain bands appears to be associated with processes occurring above the peat surface, such as burning or prolonged oxidative exposure. Oxidation of accumulated peat is unlikely because fusain bands rarely include more than a single plant.

International Journal of Coal Geology↗
USGS2017

Systematics, biostratigraphy, and dental evolution of the Palaeothentidae, later Oligocene to early-middle Miocene (Deseadan- Santacrucian) caenolestoid marsupials of South America

The family Palaeothentidae contains some of the dentally more specialized of the small-bodied marsupials of South America and was a clade almost equivalent with the Abderitidae in having been the most abundant caenolestoids. They were unquestionably the most diverse, containing two subfamilies, nine genera, and 19 species, with a distribution ranging from Colombia to Tierra del Fuego. The best and most continuous record of the Palaeothentidae is from Patagonian Argentina where eight genera and 17 species are recognized. There, the Palaeothentidae ranged in age from the Deseadan (later Oligocene) through the late Santacrucian (middle Miocene—the Santacrucian record lasting from about 19.4 m.y. to considerably less than 16.05 m.y. before the present). The family appears to have survived longer in Colombia. The palaeothentine Palaeothentes boliviensis (Bolivia) and the incertae sedis genus and species Hondathentes cazador (Colombia) are the only taxa restricted to an extra-Argentine distribution.

Journal of Paleontology↗
USGS2015

The shifting climate portfolio of the Greater Yellowstone Area

Knowledge of climatic variability at small spatial extents (< 50 km) is needed to assess vulnerabilities of biological reserves to climate change. We used empirical and modeled weather station data to test if climate change has increased the synchrony of surface air temperatures among 50 sites within the Greater Yellowstone Area (GYA) of the interior western United States. This important biological reserve is the largest protected area in the Lower 48 states and provides critical habitat for some of the world&rsquo;s most iconic wildlife. We focused our analyses on temporal shifts and shape changes in the annual distributions of seasonal minimum and maximum air temperatures among valley-bottom and higher elevation sites from 1948&ndash;2012. We documented consistent patterns of warming since 1948 at all 50 sites, with the most pronounced changes occurring during the Winter and Summer when minimum and maximum temperature distributions increased. These shifts indicate more hot temperatures and less cold temperatures would be expected across the GYA. Though the shifting statistical distributions indicate warming, little change in the shape of the temperature distributions across sites since 1948 suggest the GYA has maintained a diverse portfolio of temperatures within a year. Spatial heterogeneity in temperatures is likely maintained by the GYA&rsquo;s physiographic complexity and its large size, which encompasses multiple climate zones that respond differently to synoptic drivers. Having a diverse portfolio of temperatures may help biological reserves spread the extinction risk posed by climate change.

Montana, Wyoming↗
USGS2006

Geology and mineral deposits of the Snow Camp-Saxapahaw area, central North Carolina

The Snow Camp-Saxapahaw study area, in the Carolina slate belt in the Southeastern United States, is notable for large zones of high-sulfidation alteration in arc-related metavolcanic rocks. The area has potential for additional significant pyrophyllite and related aluminosilicate refractory mineral deposits and may have potential for small- to medium-size gold deposits also associated with the high-sulfidation hydrothermal systems. The Carolina slate belt is an elongate zone of mostly low-grade metamorphic rocks of Neoproterozoic to early Paleozoic age that extends from northeastern Georgia to southern Virginia. It is dominated by volcanic rocks but locally consists of fine-grained epiclastic sedimentary rocks. Plutons and subvolcanic bodies have intruded the rocks of the Carolina slate belt in many places and have been important in controlling the metamorphism and in localizing hydrothermal alteration. The Snow Camp-Saxapahaw area is mostly underlain by volcanic and volcaniclastic rocks and lesser amounts of intrusive shallow plutons. The volcanic rocks range in composition from basalt to rhyolite; however andesites, dacites, and rhyodacites are the most abundant. The intrusive bodies are largely granite and quartz monzonite; gabbroic bodies also are common. It was possible to establish the relative ages of only part of these rocks. Two northeast-trending fault zones and fractures divide the map area into three structural blocks; the central block was tilted down to the southwest to form a grabenlike structure. Most of the hydrothermally altered rocks and all of the intensely altered zones are confined to the downdropped block, which we think may have been calderalike in origin. A major volcanic unit, the Reedy Branch Tuff, is limited to the southwestern part of the graben and may be the youngest volcanic rock in the area. Layered rocks record one or more strong folding events, but the diversity of rock types, lack of recognizable stratigraphic markers, and uneven distribution of outcrops prevented comprehensive structural studies. Except for a few late plutons and dikes, all of the rocks of the area have been metamorphosed in middle to upper greenschist facies, and contact aureoles were recognized around some of the plutons. Several relatively small bodies of granitic rock contain plagioclase grains in which primary oscillatory zoning was unaffected by metamorphism. These were interpreted to be post-metamorphic. We think that there were three separate stages of hydrothermal alteration in the complex volcanic terrane in the area. The oldest, an area of at least 8.5 square miles (22 square kilometers), was subjected to an intense hydrothermal alteration, ranging from peripheral zones of quartz-sericite-paragonite through a patchy marginal zone of pyrophyllite, andalusite, and other high-alumina minerals, to almost totally silicified core zones. The second event resulted in large areas of weak to moderate sericitic and propylitic alteration recognizable only in the Reedy Branch Tuff. The last event was related to post-metamorphic plutons. All of the pyrophyllite-andalusite deposits and perhaps most of the gold and silver mineralization can be related to the first period of hydrothermal alteration. The subsequent metamorphism did not produce significant changes in mineral species in the zones of most intense hydrothermal alteration. Gold- and silver-bearing sulfide minerals in fracture zones along the southeastern margin of the graben may also have been deposited during this earliest alteration stage. No metallic mineralization appears to have occurred during the second event. A group of molybdenum-bearing greisenlike bodies formed during the emplacement of the youngest plutons during the post-metamorphic event. One gold-bearing sulfide zone occurs in the exocontact of one such porphyritic stock.

North Carolina↗
USGS2022

Spatial extent of seagrasses (Zostera marina and Ruppia maritima) along the central Pacific coast of Baja California, Mexico, 1999–2000

The seagrasses eelgrass ( Zostera marina ) and widgeongrass ( Ruppia maritima ) are prominent features of coastal lagoons along the Pacific coast of Baja California, Mexico, supporting a rich diversity of marine life. Yet little is known about their spatial distribution in this region. This is a concern because of declining trends in the abundance and distribution of seagrass in parts of northern Baja California and southern California. We used 7-band satellite imagery, 4-band digital multispectral videography, and 3-band color aerial photography to map the distribution of eelgrass and widgeongrass in six embayments along the central Pacific coast of Baja California. The total spatial extent of seagrass was estimated to be 42,697 hectares, of which about 70 percent was eelgrass. This seagrass was primarily lower in the intertidal than widgeongrass in all embayments. Eelgrass and widgeongrass composed the greatest proportion (47 percent) of the spatial extent in the two largest embayments, Lagunas Ojo de Liebre and San Ignacio, and these two embayments accounted for 85 percent of all seagrass in the study area. The native cordgrass ( Spartina foliosa ) and pickleweed ( Salicornia spp .) were the predominate vegetation cover type of marshes in the three northern and three southern embayments, respectively. The three southern embayments contained mangrove ( Rhizophora spp.) and the three northern embayments did not, thus marking the northern edge of mangroves along the Pacific coast of North America. This study establishes an embayment-wide baseline for continuing investigations and monitoring future changes in the spatial abundance of seagrasses in central Baja California.

Baja California↗
USGS1984

Assessment of water resources at Fort Carson Military Reservation near Colorado Springs, Colorado

The Fort Carson Military Reservation adjoins the rapidly growning Colorado Springs metropolitan area, where locally available water supplies are limited and strictly administered. Fort Carson purchases about 3,400 acre-feet of treated water annually from the city of Colorado Springs. The major streams entering Fort Carson have an estimated average annual discharge of 6,240 acre-feet of water per year upstream from diversions for municipal and domestic water supplies. The streamflow is unevenly distributed in time and consequently not dependable as a large or sole source of water. Ground water is available from alluvial and bedrock aquifers. Wells with yields greater than 100 gallons per minute can be expected from the alluvium along Rock and Little Fountain Creeks and from some parts of the Dakota-Purgatoire aquifer. The quality of surface water entering Fort Carson is generally suitable for irrigation and drinking but deteriorates eastward across Fort Carson. Water from the alluvial aquifer along Rock and Little Fountain Creeks in the eastern part of Fort Carson contains fluoride in concentrations exceeding drinking-water standards. Water from the Dakota-Purgatoire aquifer characteristically contains radiochemical constituents in concentrations that exceed drinking-water standards. (USGS)

Water-Resources Investigations Report↗
USGS2025

Characterizing the scale of regional landslide triggering from storm hydrometeorology

Rainfall strongly affects landslide triggering; however, understanding how storm characteristics relate to the severity of landslides at the regional scale has thus far remained unclear, despite the societal benefits that would result from defining this relationship. As mapped landslide inventories typically cover a small region relative to a storm system, here we develop a dimensionless index for landslide-inducing rainfall, A * , based on extremes of modeled soil water relative to its local climatology. We calibrate A * using four landslide inventories, comprising over 11 000 individual landslides over four unique storm events, and find that a common threshold can be applied to estimate regional shallow-landslide-triggering potential across diverse climatic regimes in California (USA). We then use the spatial distribution of A * , along with topography, to calculate the landslide potential area (LPA) for nine landslide-inducing storm events over the past 20 years, and we test whether atmospheric metrics describing the strength of landfalling storms, such as integrated water vapor transport, correlate with the magnitude of hazardous landslide-inducing rainfall. We find that although the events with the largest LPA do occur during exceptional atmospheric river (AR) storms, the strength of landfalling atmospheric rivers does not scale neatly with landslide potential area, and even exceptionally strong ARs may yield minimal landslide impacts. Other factors, such as antecedent soil moisture driven by storm frequency and mesoscale precipitation features within storms, are instead more likely to dictate the patterns of landslide-generating rainfall throughout the state.

California↗
USGS2011

Wyoming Landscape Conservation Initiative data management and integration

Six Federal agencies, two State agencies, and two local entities formally support the Wyoming Landscape Conservation Initiative (WLCI) and work together on a landscape scale to manage fragile habitats and wildlife resources amidst growing energy development in southwest Wyoming. The U.S. Geological Survey (USGS) was tasked with implementing targeted research and providing scientific information about southwest Wyoming to inform the development of WLCI habitat enhancement and restoration projects conducted by land management agencies. Many WLCI researchers and decisionmakers representing the Bureau of Land Management, U.S. Fish and Wildlife Service, the State of Wyoming, and others have overwhelmingly expressed the need for a stable, robust infrastructure to promote sharing of data resources produced by multiple entities, including metadata adequately describing the datasets. Descriptive metadata facilitates use of the datasets by users unfamiliar with the data. Agency representatives advocate development of common data handling and distribution practices among WLCI partners to enhance availability of comprehensive and diverse data resources for use in scientific analyses and resource management. The USGS Core Science Informatics (CSI) team is developing and promoting data integration tools and techniques across USGS and partner entity endeavors, including a data management infrastructure to aid WLCI researchers and decisionmakers.

Wyoming↗
USGS2025

Comparative genomics of Bacillus anthracis A and B-clades reveals genetic variation in genes responsible for spore germination

Bacillus anthracis , the causative agent of anthrax, is composed of three genetic clades (A, B, and C). Clade-A is the most common and distributed worldwide, B-clade has a narrow geographic distribution, and C-clade is rare. South Africa's Kruger National Park (KNP) has high diversity of B. anthracis , with strains from A and B clades described from its northernmost region, Pafuri. We employed whole genome sequencing to investigate the genomic diversity of B. anthracis strains isolated from animal carcasses ( n = 34) during the 2012–2015 outbreaks. Whole-genome single-nucleotide polymorphism (wgSNP) analysis assigned the 2012–2015 B. anthracis genomes to the A-clade branch, distributed across the branch's two minor sub-clades A.Br.005/006. Additionally, pan-genomic analysis distinguished the A- and B-clade genomes, identifying unique accessory genes. Notable genetic differences include the biosynthetic spore cell wall genes; long-chain fatty acid CoA ligases ( FaD13 ), Bacillus collagen-like protein of anthracis (BclA) involved in the exosporium germination, as well as a truncated murein DD-endopeptidase ( mepH ) found in the pXO2 plasmid of the B-clade strains. The tryptophan synthase subunit alpha gene ( trpA ), which results in a pseudogene in B-clade genomes separates the A- and B-clade genomes. These differences in biosynthetic cell wall genes suggest variation in adaptability or cell growth of the B-clade strains in the environment, further influenced by the truncation of the trpA gene involved in spore germination. The A.Br.005/006-clade strains in KNP exhibit higher genetic diversity, which may enhance their resilience to environmental stressors. In contrast, the KNP B-clade (B.Br.001/002) strains show limited genetic variation, potentially reducing their adaptability. This pattern is evident through whole-genome SNP analysis and pan-genomics investigating the evolution of B. anthracis .

Kruger National Park↗