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USGS2000

Acoustic Doppler Current Profiler Data Processing System manual [ADCP]

This open-file report describes the data processing software currently in use by the U.S. Geological Survey (USGS), Woods Hole Coastal and Marine Science Center (WHCMSC), to process time series of acoustic Doppler current data obtained by Teledyne RD Instruments Workhorse model ADCPs. The Sediment Transport Instrumentation Group (STG) at the WHCMSC has a long-standing commitment to providing scientists high quality oceanographic data published in a timely manner. To meet this commitment, STG has created this software to aid personnel in processing and reviewing data as well as evaluating hardware for signs of instrument malfunction. The output data format for the data is network Common Data Form (netCDF), which meets USGS publication standards. Typically, ADCP data are recorded in beam coordinates. This conforms to the USGS philosophy to post-process rather than internally process data. By preserving the original data quality indicators as well as the initial data set, data can be evaluated and reprocessed for different types of analyses. Beam coordinate data are desirable for internal and surface wave experiments, for example. All the code in this software package is intended to run using the MATLAB program available from The Mathworks, Inc. As such, it is platform independent and can be adapted by the USGS and others for specialized experiments with non-standard requirements. The software is continuously being updated and revised as improvements are required. The most recent revision may be downloaded from: http://woodshole.er.usgs.gov/operations/stg/Pubs/ADCPtools/adcp_index.htm The USGS makes this software available at the user?s discretion and responsibility.

Open-File Report↗

USGS2000

Laboratory performance in the Sediment Laboratory Quality-Assurance Project, 1996-98

This report describes the results of the first 3 years of an ongoing study of sediment laboratories used by the U.S. Geological Survey (USGS). The sediment laboratories currently in operation constitute the entire USGS national laboratory system for sediment analyses. As with all environmental data, physical sediment data can be expected to contain a certain amount of difference, whether the difference resulted from the collecting, transporting, or analyzing of the sample. Because it is important to know how each laboratory is performing, the USGS initiated the Sediment Laboratory Quality-Assurance (SLQA) project in August 1996. From August 1996 through June 1998, five studies were made, the results of which are the basis of this report. The focus of the project is on quantitative analyses done on water-sediment mixtures to derive suspended-sediment concentrations, sediment-mass determinations, and sand/fine separations. For the purpose of this report, all mass determinations are net values—the tare weight of the container is excluded. The fine-size material is defined as particles sieved to a size of less than 62 micrometers (µm) and sand-size material is defined as particles sieved to a size of between 63 and 125 µm. Also, in this report, class 1 samples are defined as samples containing 50 to 100 milligrams (mg) of fine-size material, class 2 samples are defined as samples containing 101 to 300 mg of fine-size material, and class 3 samples are defined as samples containing 2,200 to 3,200 mg of fine-size material. In studies 96-1 through 98-1, the amount of sand added to each sample ranged from 9 to 28 percent of the mass of fine-size material in each sample class. Analytical results from all sediment quality-control samples are compiled and statistically summarized by the USGS, Branch of Quality Systems, both on an intra- and interlaboratory basis. When evaluating these data, the reader needs to keep in mind that every measurement has an error component associated with it. It is premature to use the data from the first five SLQA studies to judge any of the laboratories as performing in an unacceptable manner. There were, however, some notable differences in the results for the 12 laboratories that participated in the five SLQA studies. For example, the overall median percent difference for suspended-sediment concentration on an individual laboratory basis ranged from –18.04 to –0.33 percent. Five of the 12 laboratories had an overall median percent difference for suspended-sediment concentration of –2.02 to –0.33 percent. There was less variability in the median difference for the measured fine-size material mass. The overall median percent difference for fine-size material mass ranged from –10.11 to –4.27 percent. Except for one laboratory, the median difference for fine-size material mass was within a fairly narrow range of –6.76 to –4.27 percent. The median percent difference for sand-size material mass differed among laboratories more than any other physical sediment property measured in the study. The overall median percent difference for the sand-size material mass ranged from –1.49 percent to 26.39 percent. Five of the nine laboratories that do sand/fine separations had overall median percent differences that ranged from –1.49 to 2.98 percent for sand-size material mass. Careful review of the data reveals that certain laboratories consistently produced data within statistical control limits for some or all of the physical sediment properties measured in this study, whereas other laboratories occasionally produced data that exceeded the control limits.

Water-Resources Investigations Report↗

USGS2015

Effects of the environmental estrogenic contaminants bisphenol A and 17α-ethinyl estradiol on sexual development and adult behaviors in aquatic wildlife species

Endocrine disrupting chemicals ( EDCs ), including the mass-produced component of plastics, bisphenol A (BPA) are widely prevalent in aquatic and terrestrial habitats. Many aquatic species, such as fish, amphibians, aquatic reptiles and mammals, are exposed daily to high concentrations of BPA and ethinyl estradiol (EE2), estrogen in birth control pills. In this review, we will predominantly focus on BPA and EE2, well-described estrogenic EDCs. First, the evidence that BPA and EE2 are detectable in almost all bodies of water will be discussed. We will consider how BPA affects sexual and neural development in these species, as these effects have been the best characterized across taxa. For instance, such chemicals have been in many cases reported to cause sex-reversal of males to females. Even if these chemicals do not overtly alter the gonadal sex, there are indications that several EDCs might demasculinize male-specific behaviors that are essential for attracting a mate. In so doing, these chemicals may reduce the likelihood that these males reproduce. If exposed males do reproduce, the concern is that they will then be passing on compromised genetic fitness to their offspring and transmitting potential transgenerational effects through their sperm epigenome . We will thus consider how diverse epigenetic changes might be a unifying mechanism of how BPA and EE2 disrupt several processes across species. Such changes might also serve as universal species diagnostic biomarkers of BPA and other EDCs exposure. Lastly, the evidence that estrogenic EDCs-induced effects in aquatic species might translate to humans will be considered.

General and Comparative Endocrinology↗

USGS2021

Methodology and technical input for the 2021 review and revision of the U.S. Critical Minerals List

Pursuant to Section 7002 (“Mineral Security”) of Title VII (“Critical Minerals”) of the Energy Act of 2020 (Public Law 116–260, December 27, 2020, 116th Cong.), the Secretary of the Interior, acting through the Director of the U.S. Geological Survey, is tasked with reviewing and revising the methodology used to evaluate mineral criticality and the U.S. Critical Minerals List no less than every 3 years. The initial Critical Minerals List was published in the Federal Register on May 18, 2018, in response to Executive Order No. 13817, A Federal Strategy to Ensure Secure and Reliable Supplies of Critical Minerals (3 CFR, 2017 Comp, p. 397–399). This report documents the updated evaluation methodology and the resultant updated draft list of minerals recommended for inclusion in the Critical Minerals List.

Open-File Report↗

USGS1993

Proceedings of the symposium on the management of prairie dog complexes for the reintroduction of the black-footed ferret

The workshop featured a review of current knowledge in the biology of prairie dogs in the context of managing black-footed ferret habitat. The review addressed two main components. The first consisted of a series of papers on prairie dog habitat and biology. The second component of the workshop was a summary of the participants' discussion about managing prairie dog complexes. This discussion was based on the previously identified papers and profited from the participants' expertise on the ecology of black-footed ferrets and prairie dogs. The report provides current and comprehensive information about management of habitat for prairie dogs and black-footed ferrets and is a useful guide for agencies and individuals that manage black-footed ferrets.

Biological Report↗

USGS2010

Spatial Databases of Geological, Geophysical, and Mineral Resource Data Relevant to Sandstone-Hosted Copper Deposits in Central Kazakhstan

Central Kazakhstan is host to one of the world's giant sandstone-hosted copper deposits, the Dzhezkazgan deposit, and several similar, smaller deposits. The United Stated Geological Survey (USGS) is assessing the potential for other, undiscovered deposits of this type in the surrounding region of central Kazakhstan. As part of this effort, Syusyura compiled and partially translated an array of mostly unpublished geologic, geophysical, and mineral resource data for this region in digital format from the archives of the former Union of Soviet Socialists Republics (of which Kazakhstan was one of the member republics until its dissolution in 1991), as well as from later archives of the Republic of Kazakhstan or of the Kazakhstan consulting firm Mining Economic Consulting (MEC). These digital data are primarily map-based displays of information that were transmitted either in ESRI ArcGIS, georeferenced format, or non-georeferenced map image files. Box and Wallis reviewed all the data, translated Cyrillic text where necessary, inspected the maps for consistency, georeferenced the unprojected map images, and reorganized the data into the filename and folder structure of this publication.

Open-File Report↗

USGS1983

Ground-followup studies of the 1977 airborne electromagnetic survey in the Assifar and Mulhal areas, Wadi Bidah district, Kingdom of Saudi Arabia

Parts of four airborne electromagnetic (AEM) anomalies were selected for study in order to determine the cause of high conductivity of Precambrian rocks underlying extensive areas in the southern Wadi Bidah district, Kingdom of Saudi Arabia. In the Assifar area, which contains an ancient mine or prospect having the same name, geophysical data suggest that a mineralized body may lie beneath and immediately south of the ancient workings. Many other conductive zones detected during the course of the geophysical survey are thought to be related to metavolcanic rocks containing carbonaceous materials. Detailed geologic mapping, and possibly diamond core drilling, will be necessary to fully evaluate the area. In the Mulhal No. 2 area, located about 2 km south of the Mulhal ancient mine, geophysical studies suggest that mineralized rocks extend about 500 m along strike beneath outcrops of gossanous material. A brief review of the AEM ground-followup studies in the Wadi Bidah district suggests that most, if not all, of the AEM conductors are carbonaceous rocks. Secondary causes of conductivity are intense faulting and shearing.

Open-File Report↗

USGS1996

Fracture patterns and their origin in the upper Devonian Antrim Shale gas reservoir of the Michigan basin: A review

INTRODUCTION: Black shale members of the Upper Devonian Antrim Shale are both the source and reservoir for a regional gas accumulation that presently extends across parts of six counties in the northern part of the Michigan basin (fig. 1). Natural fractures are considered by most petroleum geologists and oil and gas operators who work the Michigan basin to be a necessary condition for commercial gas production in the Antrim Shale. Fractures provide the conduits for free gas and associated water to flow to the borehole through the black shale which, otherwise, has a low matrix permeability. Moreover, the fractures assist in the release of gas adsorbed on mineral and(or) organic matter in the shale (Curtis, 1992). Depths to the gas-producing intervals (Norwood and Lachine Members) generally range from 1,200 to 1,800 ft (Oil and Gas Journal, 1994). Locally, wells that produce gas from the accumulation are as deep as 2,200 (Oil and Gas Journal, 1994). Even though natural fractures are an important control on Antrim Shale gas production, most wells require stimulation by hydraulic fracturing to attain commercial production rates (Kelly, 1992). In the U.S. Geological Survey's National Assessment of United States oil and gas, Dolton (1995) estimates that, at a mean value, 4.45 trillion cubic feet (TCF) of gas are recoverable as additions to already discovered quantities from the Antrim Shale in the productive area of the northern Michigan trend. Dolton (1995) also suggests that undiscovered Antrim Shale gas accumulations exist in other parts of the Michigan basin. The character, distribution, and origin of natural fractures in the Antrim Shale gas accumulation have been studied recently by academia and industry. The intent of these investigations is to: 1) predict 'sweet spots', prior to drilling, in the existing gas-producing trend, 2) improve production practices in the existing trend, 3) predict analogous fracture-controlled gas accumulations in other parts of the Michigan basin, and 4) improve estimates of the recoverable gas in the Antrim Shale gas plays (Dolton, 1995). This review of published literature on the characteristics of Antrim Shale fractures, their origin, and their controls on gas production will help to define objectives and goals in future U.S. Geological Survey studies of Antrim Shale gas resources.

Michigan↗

USGS2000

Natural attenuation of chlorinated volatile organic compounds in ground water at Area 6, Naval Air Station Whidbey Island, Washington

Natural attenuation is a viable alternative to pump and treat for meeting remediation objectives in the vicinity of the southern contaminant plume. The combination of historically low contaminant concentrations in ground water, a landfill cap that limits source area contributions, favorable conditions for degradation of VC, and a relatively long downgradient distance to potential receptors are all favorable for natural attenuation as a remediation alternative. Natural attenuation could effectively meet all but one remediation goal that extraction wells PW- 2, PW-4, PW-6, PW-7, PW-8 and PW-9 are currently being employed to meet. The goal of preventing migration of all VC across the site boundary could not be met by natural attenuation. Some VC would migrate south of the Navy boundary, but the potential for subsequent VC mineralization downgradient of the base and the existing institutional controls would result in minimal additional risk from using natural attenuation. In the western contaminant plume natural attenuation is not currently a viable alternative to pump and treat for meeting remediation objectives. There is a possibility that rates for reductive dechlorination of TCE and TCA could increase substantially if the plume was allowed to migrate beneath the Oak Harbor landfill, but there are not enough data to be certain of such an increase. TCA and TCE concentrations at the leading edge of the western plume need to be reduced to at least 25 and 40 µg/L, respectively, to be protective of potential downgradient receptors. Source area TCA and TCE concentrations have decreased substantially over the past ten years, and the extraction wells PW-3 and PW-5 in particular are removing a significant mass of contaminants from ground water, so natural attenuation may be a viable alternative for the western plume in the future. There would be some possible side benefits of using natural attenuation as an alternative to pump and treat in the southern contaminant plume. The first would be that the resulting decrease in the amount of treated water that would need to be recharged in the swale north of the landfill would result in less off-base migration of contamination across the western site boundary. The second benefit would be a substantial reduction in the amount of dissolved iron and manganese being extracted from the shallow aquifer and run through the treatment system. Removing that source of operation and maintenance problems would result in more effective containment and removal of contamination in the western contaminant plume. The most critical data gap identified in this evaluation is the paucity of contaminant chemistry information downgradient of the Navy boundary in the vicinity of the southern contaminant plume. Without such data, the behavior of the plume and the protectiveness of natural attenuation to downgradient receptors cannot be verified, and field attenuation rates for VC cannot be determined directly. The existing long-term monitoring plan would need to be reviewed and revised if natural attenuation is selected as a remedy for the contamination in the southern plume. In particular, additional performance monitoring wells may be required downgradient of the property.

Washington↗

USGS1996

Scour at bridge sites in Delaware, Maryland, and Virginia

Scour data were obtained from discharge measure- ments to develop and evaluate the reliability of constriction-scour and local-scour equations for rivers in Delaware, Maryland, and Virginia. No independent constriction-scour or local-scour equations were developed from the data because no significant relation was deter-mined between measured scour and streamflow, streambed, and bridge characteristics. Two existing equations were evaluated for prediction of constriction scour and 14 existing equations were evaluated for prediction of local scour. Constriction-scour data were obtained from historical stream discharge measurements, field surveys, and bridge plans at nine bridge sites in the three-State area. Constriction scour was computed by subtracting the average-streambed elevation in the constricted reach from an uncontracted-channel reference elevation. Hydraulic conditions were estimated for the measurements with the greatest discharges by use of the Water-Surface Profile computation model. Measured and calculated constriction-scour data were used to evaluate the reliability of Laursen's clear-water constriction-scour equation and Laursen's live-bed constriction-scour equation. Laursen's clear-water constriction-scour equation underestimated 21 of 23 scour measure- ments made at three sites. A sensitivity analysis showed that the equation is extremely sensitive to estimates of the channel-bottom width. Reduction in estimates of bottom width by one-third resulted in predictions of constriction scour slightly greater than measured values for all scour measurements. Laursen's live-bed constriction- scour equation underestimated 10 of 14 scour measurements made at one site. The error between measured and predicted constriction scour was less than 1.0 ft (feet) for 12 measure-ments and less than 0.5 ft for 8 measurements. Local-scour data were obtained from stream discharge measurements, field surveys, and bridge plans at 15 bridge sites in the three-State area. The reliability of 14 local-scour equations were evaluated. From visual inspection of the plotted data, the Colorado State University, Froehlich design, Laursen, and Mississippi pier-scour equations appeared to be the best predictors of local scour. The Colorado State University equation underestimated 11 scour depths in clear-water scour conditions by a maximum of 2.4 ft, and underestimated 3 scour depth in live-bed scour conditions by a maximum of 1.3 ft. The Froehlich design equation under- estimated two scour depth in clear-water scour conditions by a maximum of 1.2 ft, and under- estimated one scour depth in live-bed scour conditions by a maximum of 0.4 ft. Laursen's equation overestimated the maximum scour depth in clear-water scour conditions by approximately one-half pier width or approximately 1.5 ft, and overestimated the maximum scour depth in live-bed scour conditions by approximately one-pier width or approximately 3 ft. The Mississippi equation underestimated six scour depths in clear-water scour conditions by a maximum of 1.2 ft, and underestimated one scour depth in live-bed scour conditions by 1.6 ft. In both clear-water and live-bed scour conditions, the upper limit for the depth of scour to pier-width ratio for all local scour measurements was 2.1. An accurate pier- approach velocity is necessary to use many local pier-scour equations for bridge design. Velocity data from all the discharge measurements reviewed for this investigation were used to develop a design curve to estimate pier-approach velocity from mean cross-sectional velocity. A least- squares regression and offset were used to envelop the velocity data.

Water-Resources Investigations Report↗

USGS2009

Estimation of Leakage Potential of Selected Sites in Interstate and Tri-State Canals Using Geostatistical Analysis of Selected Capacitively Coupled Resistivity Profiles, Western Nebraska, 2004

With increasing demands for reliable water supplies and availability estimates, groundwater flow models often are developed to enhance understanding of surface-water and groundwater systems. Specific hydraulic variables must be known or calibrated for the groundwater-flow model to accurately simulate current or future conditions. Surface geophysical surveys, along with selected test-hole information, can provide an integrated framework for quantifying hydrogeologic conditions within a defined area. In 2004, the U.S. Geological Survey, in cooperation with the North Platte Natural Resources District, performed a surface geophysical survey using a capacitively coupled resistivity technique to map the lithology within the top 8 meters of the near-surface for 110 kilometers of the Interstate and Tri-State Canals in western Nebraska and eastern Wyoming. Assuming that leakage between the surface-water and groundwater systems is affected primarily by the sediment directly underlying the canal bed, leakage potential was estimated from the simple vertical mean of inverse-model resistivity values for depth levels with geometrically increasing layer thickness with depth which resulted in mean-resistivity values biased towards the surface. This method generally produced reliable results, but an improved analysis method was needed to account for situations where confining units, composed of less permeable material, underlie units with greater permeability. In this report, prepared by the U.S. Geological Survey in cooperation with the North Platte Natural Resources District, the authors use geostatistical analysis to develop the minimum-unadjusted method to compute a relative leakage potential based on the minimum resistivity value in a vertical column of the resistivity model. The minimum-unadjusted method considers the effects of homogeneous confining units. The minimum-adjusted method also is developed to incorporate the effect of local lithologic heterogeneity on water transmission. Seven sites with differing geologic contexts were selected following review of the capacitively coupled resistivity data collected in 2004. A reevaluation of these sites using the mean, minimum-unadjusted, and minimum-adjusted methods was performed to compare the different approaches for estimating leakage potential. Five of the seven sites contained underlying confining units, for which the minimum-unadjusted and minimum-adjusted methods accounted for the confining-unit effect. Estimates of overall leakage potential were lower for the minimum-unadjusted and minimum-adjusted methods than those estimated by the mean method. For most sites, the local heterogeneity adjustment procedure of the minimum-adjusted method resulted in slightly larger overall leakage-potential estimates. In contrast to the mean method, the two minimum-based methods allowed the least permeable areas to control the overall vertical permeability of the subsurface. The minimum-adjusted method refined leakage-potential estimation by additionally including local lithologic heterogeneity effects.

Scientific Investigations Report↗

USGS2003

A new species of Moraria (Crustacea: Copepoda: Harpacticoida) from the Laurentian Great Lakes

Moraria hudsoni n. sp. is described from Trails End Bay in Lake Michigan and Prentiss Bay in Lake Huron, Michigan, USA. The new species differs from its congeners in chaetotaxy, body ornamentation, and other characters. We review published records of members of Moraria from North and Central America; no species is known from South America. Species of this genus have been found in the mountains of southern Mexico, Guatemala, and Honduras, but none of these has been validly described. In North America, eight species have been recorded from Alaska, Canada, and the conterminous USA as far south as North Carolina. We report new geographical records of M. affinis from Virginia, and of both M. cristata and M. virginiana from Maryland and Virginia. We provide a tabular key to aid in identification of the named species of Moraria in North America.

Maryland, Michigan, Virginia↗

USGS2020

Methods for estimating vital rates of greater sage-grouse broods: A review

Biologists use a variety of methods to estimate productivity and resource selection of birds. The effectiveness and suitability of each method depends on the study's objectives, but is also influenced by many important traits, including detection probability, disturbance of focal birds and sampling frequency. We reviewed 504 greater sage-grouse Centrocercus urophasianus papers published from 1990 to 2019 to document the most common brood survey methods used by investigators and summarized if and how they used brood survey data to estimate brood survival and detection probability. Of the 504 papers, 16.1% (n = 81) had useful information relevant to the review. The most common methods included daytime visual surveys (46.9%; n = 38), daytime flush surveys (33.3%; n = 27), nocturnal spotlight surveys (19.8%; n = 16), radio-tagged chicks (16.0%; n = 13), wing surveys (9.9%; n = 8), brood routes (4.9%; n = 4) and pointing dogs (4.9%; n = 4). Fifty-nine of the 81 papers used >1 method, only 2 of the 81 papers measured or reported detection probability, and none reported the level of disturbance caused by the method. Studies varied widely regarding the age of the brood when brood fate was confirmed (x̄ = 44.4 days post-hatch, range 14–84 days). The frequency of brood sampling visits also varied greatly among studies (range = 1.19–3.85 surveys/brood/week) and this variation complicates comparison in fecundity and survival estimates across studies. Furthermore, 35 papers used >1 maternal behavior as purported indicators of brood fate, but none of them documented how accurate their indicators were. Future studies could reduce variance in estimates of sage-grouse fecundity and brood survival by employing empirical methods to estimate detection probability, standardizing brood sampling methods and conducting trials to document the effects of hen or brood capture, handling and flushing on brood survival estimates. Moreover, the accuracy of commonly used indicators of brood fate, including maternal behaviors, flocking behavior and distance moved after flush needs verification.

Wildlife Biology↗

USGS2016

Sediment acoustic index method for computing continuous suspended-sediment concentrations

Suspended-sediment characteristics can be computed using acoustic indices derived from acoustic Doppler velocity meter (ADVM) backscatter data. The sediment acoustic index method applied in these types of studies can be used to more accurately and cost-effectively provide time-series estimates of suspended-sediment concentration and load, which is essential for informed solutions to many sediment-related environmental, engineering, and agricultural concerns. Advantages of this approach over other sediment surrogate methods include: (1) better representation of cross-sectional conditions from large measurement volumes, compared to other surrogate instruments that measure data at a single point; (2) high temporal resolution of collected data; (3) data integrity when biofouling is present; and (4) less rating curve hysteresis compared to streamflow as a surrogate. An additional advantage of this technique is the potential expansion of monitoring suspended-sediment concentrations at sites with existing ADVMs used in streamflow velocity monitoring. This report provides much-needed standard techniques for sediment acoustic index methods to help ensure accurate and comparable documented results. A sediment acoustic index gage is used to collect continuous acoustic backscatter data, using an ADVM deployed in a fixed location, which are related to results from discrete suspended-sediment samples. The raw ADVM backscatter data are adjusted for variables affecting backscatter other than the sediment concentration to compute the sediment-corrected backscatter ( SCB ) and sediment attenuation coefficient ( SAC ). The sediment acoustic index rating (rating) is then developed by relating the sediment characteristics from the periodic samples to the SCB and (or) SAC and other explanatory variables in a site-specific, instrument-specific, simple or multiple linear regression model. The rating is reviewed and checked to ensure the technique has been applied appropriately. This review includes an assessment of the theoretical soundness, the adequacy of the model calibration dataset, and the quality of the regression model and regression diagnostics. The rating can then be applied to the acoustic surrogates and other explanatory variables to obtain continuous records of computed suspended-sediment concentration. The estimates of suspended-sediment concentration can then be paired with streamflow data, if available, to compute continuous records of suspended-sediment load. Once developed, sediment acoustic index ratings must be validated with additional suspended-sediment samples, beyond the period of record used in the rating development, to verify that the regression model continues to adequately represent sediment conditions within the stream. Changes in ADVM configuration or installation, or replacement with another ADVM, may require development of a new rating. The best practices described in this report can be used to develop continuous estimates of suspended-sediment concentration and load using sediment acoustic surrogates to enable more informed and accurate responses to diverse sedimentation issues.

Techniques and Methods↗

USGS2006

The changing shapes of active volcanoes: History, evolution, and future challenges for volcano geodesy

At the very heart of volcanology lies the search for the 'plumbing systems' that form the inner workings of Earth’s active volcanoes. By their very nature, however, the magmatic reservoirs and conduits that underlie these active volcanic systems are elusive; mostly they are observable only through circumstantial evidence, using indirect, and often ambiguous, surficial measurements. Of course, we can infer much about these systems from geologic investigation of materials brought to the surface by eruptions and of the exposed roots of ancient volcanoes. But how can we study the magmatic processes that are occurring beneath Earth’s active volcanoes? What are the geometry, scale, physical, and chemical characteristics of magma reservoirs? Can we infer the dynamics of magma transport? Can we use this information to better forecast the future behavior of volcanoes? These questions comprise some of the most fundamental, recurring themes of modern research in volcanology. The field of volcano geodesy is uniquely situated to provide critical observational constraints on these problems. For the past decade, armed with a new array of technological innovations, equipped with powerful computers, and prepared with new analytical tools, volcano geodesists have been poised to make significant advances in our fundamental understanding of the behavior of active volcanic systems. The purpose of this volume is to highlight some of these recent advances, particularly in the collection and interpretation of geodetic data from actively deforming volcanoes. The 18 papers that follow report on new geodetic data that offer valuable insights into eruptive activity and magma transport; they present new models and modeling strategies that have the potential to greatly increase understanding of magmatic, hydrothermal, and volcano-tectonic processes; and they describe innovative techniques for collecting geodetic measurements from remote, poorly accessible, or hazardous volcanoes. To provide a proper context for these studies, we offer a short review of the evolution of volcano geodesy, as well as a case study that highlights recent advances in the field by comparing the geodetic response to recent eruptive episodes at Mount St. Helens. Finally, we point out a few areas that continue to challenge the volcano geodesy community, some of which are addressed by the papers that follow and which undoubtedly will be the focus of future research for years to come.

Journal of Volcanology and Geothermal Research↗

USGS1983

A guide to the larvae of the Nearctic Diamesinae (Diptera; Chironomidae), the genera Boreoheptagyia, Protanypus, Diamesa, and Pseudokiefferiella

The subfamily Diamesinae consists of the monogeneric tribes Boreoheptagnini and Parotanypini and the diverse tribe Diamesini with seven genera. These midges are prevalent in clean, cool arctic-alpine waters, but less abundant in the lowlands. Keys and descriptions herein to the known species of these nine genera may prove valuable in the biomonitoring of these cool aquatic habitats. The larvae of Protanypus saetheri Wiederholm is described for the first time. Identification is based upon the absence of other species in the collection area. Examination of a series of larval D. incallida Walker collected in Wyoming and a review of pertinent literature shows that there is considerable variation in the procerus and the labral armature. Because these characters are often used in keys, this variability can lead to misidentification of less recognizable species of Diamesa. (USGS)

Water-Resources Investigations Report↗

USGS2006

Special issue: The changing shapes of active volcanoes: Recent results and advances in volcano geodesy

The 18 papers herein report on new geodetic data that offer valuable insights into eruptive activity and magma transport; they present new models and modeling strategies that have the potential to greatly increase understanding of magmatic, hydrothermal, and volcano-tectonic processes; and they describe innovative techniques for collecting geodetic measurements from remote, poorly accessible, or hazardous volcanoes. To provide a proper context for these studies, we offer a short review of the evolution of volcano geodesy, as well as a case study that highlights recent advances in the field by comparing the geodetic response to recent eruptive episodes at Mount St. Helens. Finally, we point out a few areas that continue to challenge the volcano geodesy community, some of which are addressed by the papers that follow and which undoubtedly will be the focus of future research for years to come.

Journal of Volcanology and Geothermal Research↗

USGS2021

Identifying the ecological and management implications of mangrove migration in the northern Gulf of Mexico

Climate change is transforming ecosystems and affecting ecosystem goods and services. Along the Gulf of Mexico and Atlantic coasts of the southeastern United States, the frequency and intensity of extreme freeze events greatly influences whether coastal wetlands are dominated by freeze-sensitive woody plants (mangrove forests) or freeze-tolerant grass-like plants (salt marshes). In response to warming winters, mangroves have been expanding and displacing salt marshes at varying degrees of severity in parts of north Florida, Louisiana, and Texas. As winter warming accelerates, mangrove range expansion is expected to increasingly modify wetland ecosystem structure and function. Because there are differences in the ecological and societal benefits that salt marshes and mangroves provide, coastal environmental managers are challenged to anticipate effects of mangrove expansion on critical wetland ecosystem services, including those related to carbon sequestration, wildlife habitat, storm protection, erosion reduction, water purification, fisheries support, and recreation. This project produced information that is relevant to scientists and coastal resource managers working within the transition zone between mangrove forests and salt marshes. The two primary products are: (1) an investigation that leverages data and information from a community-curated data network called the Mangrove Migration Network to refine temperature thresholds for mangrove range expansion in a warming climate; and (2) a review article that examines current understanding of the effects of mangrove range expansion and displacement of salt marshes on wetland ecosystem services, including those related to carbon sequestration, wildlife habitat, storm protection, erosion reduction, water purification, fisheries support, and recreation.

Alabama, Florida, Louisiana, Mississippi, Texas↗