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At least 55 records · Page 3Linked to original sources
USGS2019

Conserving transboundary wildlife migrations: Recent insights from the Greater Yellowstone Ecosystem

Animal migrations are ecologically, culturally, and economically important. Ungulate populations in many parts of Africa, Asia, Europe, and the Americas migrate long distances to access seasonally available resources, traversing vast landscapes in large numbers. Yet some migrations are declining, raising concerns among scientists and natural resource managers. We synthesize recent advances in ungulate migration ecology with relevance to management and policy. Using case studies from the Greater Yellowstone Ecosystem (GYE), we show how new tools can be applied to map ungulate migrations and assess threats across multiple seasonal habitats, serving as a conservation roadmap. To help conserve ungulate migrations, we also propose a transboundary science, policy, and management framework that could be adapted beyond the GYE and that encompasses the needs of multiple species. The key elements of this framework consist of more widespread mapping and assessment of migrations, improved federal and state coordination across jurisdictional lines, increased investment in private land conservation, and strong engagement of local stakeholders positioned to sustain conservation activities over the long term.

Idaho, Montana, Wyoming↗
USGS2024

Special topic—Boreholes

Introduction Installation of instrument packages in deep (several hundred to several thousand meters) boreholes near volcanoes is relatively expensive (a few million to tens of millions of U.S. dollars), but can provide a low-noise, high-quality source of geophysical (seismic, strain, tilt, and pore pressure), physical (temperature and water level), and geochemical data. Observations from instruments at depth have the potential to provide insights into processes associated with magma intrusion, unrest, and eruption that would not otherwise be possible (Lowenstern and others, 2017; Eichelberger, 2020). Examples of instrumented boreholes in volcanic areas include the 3-kilometer (km)-deep Long Valley Exploratory Well (LVEW) in California (for example, Priest and others, 1998; Prejean and Ellsworth, 2001; Fischer and others, 2003; Roeloffs and others, 2003; Sorey and others, 2003), the 1,262 meter-deep NSF Well (commonly referred to as the “Keller Well”) within the summit caldera of Kīlauea, Hawaiʻi (Keller and others, 1979; Myren and others, 2006), and the Caribbean Andesite Lava Island-volcano Precision Seismo-geodetic Observatory (CALIPSO) project at Soufrière Hills, Montserrat, which includes a series of four 200-meter (m)-deep holes (for example, Mattioli and others, 2004; Voight and others, 2006). The Plate Boundary Observatory (PBO) of the National Science Foundation’s Earthscope project placed seismometers, tiltmeters, strainmeters, and pore-pressure sensors at depths of 100 to 250 m in more than 100 boreholes scattered in western North America, including at Mount St. Helens, Washington, and Yellowstone Caldera, Wyoming. The total cost for an instrumented PBO borehole ranged from $250,000 to $270,000 U.S. dollars (USD) and a few thousand USD are required annually for maintenance (David Mencin, UNAVCO, written commun., October 2020).

Scientific Investigations Report↗
USGS2018

History and dynamics of the Greater Yellowstone Glacial System during the last two glaciations

The Greater Yellowstone Glacial System (GYGS) covered about 20,000 km2 at its maximum Pleistocene extent. The initiation, culmination, and ultimate decay of the GYGS involved complex interactions between several coalescent ice masses flowing from glacial source areas adjoining and including the Yellowstone Plateau. Here, we present an updated review of the history and dynamics of the GYGS during the penultimate (Bull Lake) and last (Pinedale) glaciations, drawing upon an integration of glacial-geologic mapping with >130 cosmogenic 10Be and 3He exposure ages. Bull Lake glacial deposits in greater Yellowstone are dated to ca. 150–140 ka and correlate with marine isotope stage 6. The Bull Lake glaciation extended well beyond the Pinedale along the southern and western GYGS margins, but Pinedale glaciers overrode Bull Lake ice limits on the north and east sides. The northeastward shift of the center of ice mass from Bull Lake to Pinedale time may be explained by uplift on the leading edge of the Yellowstone hotspot and subsidence on the trailing margin. In early Pinedale time (∼22–18 ka), ice buildup culminated in the high terrain of the Beartooth Uplift and High Absaroka Range. Glaciers from these source regions flowed onto the northeastern margin of the Yellowstone Plateau and advanced to terminal moraines beyond Clarks Fork Canyon and in Jackson Hole. By middle Pinedale time (∼18–16 ka), the Yellowstone Plateau ice cap surface had risen above the equilibrium-line altitude, stimulating orographic glacial buildup nourished by storms funneled eastward through the Snake River Plain. The plateau ice cap eventually thickened to >1000 m and joined glaciers from the Beartooth Uplift and Gallatin Range to form the northern Yellowstone outlet glacier. Terrain east and downwind of the ice cap crest was placed in a precipitation shadow, resulting in glacial recession in these regions. During the late Pinedale (∼16–13 ka), the plateau ice cap prograded southwestward toward the direction of moisture supply, leading to advances along the southern and western margins of the GYGS. Northern sectors of the plateau ice cap were nearly stagnant at this time. The Yellowstone region experienced widespread deglaciation ca. 15–14 ka in response to warming climate. Unloading of the ∼1 km-thick plateau ice cap and consequent release of pressure on the magmatic system beneath Yellowstone was not accompanied by volcanism, indicating that the magma chamber was not primed to erupt via decompression during the last deglaciation.

Idaho, Montana Wyoming↗
USGS2021

The interactive effects of stream temperature, stream size, and non-native species on Yellowstone cutthroat trout

Climate change and non-native species are considered two of the biggest threats to native salmonids in North America. We evaluated how non-native salmonids and stream temperature and discharge were associated with Yellowstone cutthroat trout ( Oncorhynchus clarkii bouvieri ) distribution, abundance, and body size to gain a more complete understanding of the existing threats to native populations. Allopatric Yellowstone cutthroat trout were distributed across a wide range of average August temperatures (3.2 to 17.7 °C), but occurrence significantly declined at colder temperatures (<10 °C) with increasing numbers of non-natives. At warmer temperatures, occurrence remained high, despite sympatry with non-natives. Yellowstone cutthroat trout relative abundance was significantly reduced with increasing abundance of non-natives, with the greatest impacts at colder temperatures. Body sizes of large Yellowstone cutthroat trout (90th percentile) significantly increased with warming temperatures and larger stream size, highlighting the importance of access to these more productive stream segments. Considering multiple population-level attributes demonstrates the complexities of how native salmonids (such as Yellowstone cutthroat trout) are likely to be affected by shifting climates.

Idaho, Wyoming↗
USGS2016

Missouri River Scaphirhynchus albus (pallid sturgeon) effects analysis—Integrative report 2016

The Missouri River Pallid Sturgeon Effects Analysis was designed to carry out three components of an assessment of how Missouri River management has affected, and will affect, population dynamics of endangered Scaphirhynchus albus (pallid sturgeon): (1) collection of reliable scientific information, (2) critical assessment and synthesis of available data and analyses, and (3) analysis of the effects of actions on listed species and their habitats. This report is a synthesis of the three components emphasizing development of lines of evidence relating potential future management actions to pallid sturgeon population dynamics. We address 21 working management hypotheses that emerged from an expert opinion-based filtering process. The ability to quantify linkages from abiotic changes to pallid sturgeon population dynamics is compromised by fundamental information gaps. Although a substantial foundation of pallid sturgeon science has been developed during the past 20 years, our efforts attempt to push beyond that understanding to provide predictions of how future management actions may affect pallid sturgeon responses. For some of the 21 hypotheses, lines of evidence are limited to theoretical deduction, inference from sparse empirical datasets, or expert opinion. Useful simulation models have been developed to predict the effects of management actions on survival of drifting pallid sturgeon free embryos in the Yellowstone and Upper Missouri River complex (hereafter referred to as the “upper river”), and to assess the effects of flow and channel reconfigurations on habitat availability in the Lower Missouri River, tributaries, and Mississippi River downstream of Gavins Point Dam (hereafter referred to as the “lower river”). A population model also has been developed that can be used to assess sensitivity of the population to survival of specific life stages, assess some hypotheses related to stocking decisions, and explore a limited number of management scenarios. Consideration of lines of evidence for each of the 21 hypotheses includes a discussion of how the degree of uncertainty and risk associated with each hypothesis may guide science and implementation strategies. Implementation strategies include full implementation in the field, limited implementations as field-scale experiments, or (in the case of greatest uncertainty) implementation as learning actions, including research and opportunistic experiments or field-based gradient studies. Given the substantive uncertainties associated with pallid sturgeon population dynamics and the need to continually assimilate and assess new information, we proposed that an Effects Analysis-like process should be considered an integral part of ongoing Missouri River adaptive management.

Missouri↗
USGS2019

Riverine turtles select habitats maintained by natural discharge regimes in an unimpounded large river

Turtle populations are imperiled worldwide, but limited ecological information from unaltered systems hampers science‐based management and conservation of some species, especially riverine turtles such as the spiny softshell ( Apalone spinifera ). We therefore investigated movements and spatial habitat selection of 54 A . spinifera in 633 river kilometres (rkm) of the least‐altered river in the conterminous United States—the Yellowstone River in Montana—from 2005 to 2009. Movement rates and home ranges were smaller than in fragmented, altered river systems because nesting and overwintering habitats were common and in close proximity. Habitat selection also differed. A . spinifera in the Yellowstone River overwintered in unaltered bluff pools and summered in complex reaches with side channels, islands, and diverse habitats. However, those in the highly altered Missouri River used deep alluvial pools for overwintering and flooded, inundated, or backwatered tributary mouths in spring and summer. Importantly, selected habitats in both rivers were functionally similar, including complex river reaches (with multiple channels, islands, and diverse habitats) and natural pool types. Unfortunately, these are the very habitats that are limited in rivers affected by dams, bank stabilization, and channelization. Therefore, preservation of natural and diverse riverine habitats—and the fluvial dynamics that maintain them—may enhance conservation of A . spinifera in large rivers.

Montana, North Dakota, South Dakota, Wyoming↗
USGS2021

Multi-proxy record of Holocene paleoenvironmental conditions from Yellowstone Lake, Wyoming, USA

A composite 11.82 m-long (9876–-67 cal yr BP) sediment record from Yellowstone Lake, Wyoming was analyzed using a robust set of biological and geochemical proxies to investigate the paleoenvironmental evolution of the lake and its catchment in response to long-term climate forcing. Oxygen isotopes from diatom frustules were analyzed to reconstruct Holocene climate changes, and pollen, charcoal, diatom assemblages, and biogenic silica provided information on terrestrial and limnological responses. The long-term trends recorded in the terrestrial and limnic ecosystems over the last 9800 years reflect the influence of changes in the amplification of the seasonal cycle of insolation on regional climate. The early Holocene (9880–6700 cal yr BP) summer insolation maximum and strengthening of the northeastern Pacific subtropical high-pressure system created warm dry conditions and decreasing summer insolation in the middle (6700–3000 cal yr BP) and late (3000–-67 cal yr BP) Holocene resulted in progressively cooler, wetter conditions. Submillenial climate variation is also apparent, with a wetter/cooler interval between 7000 and 6800 cal yr BP and warmer and/or drier conditions from 4500 to 3000 cal yr BP and at ca. 1100 cal yr BP. These data show that the Yellowstone Lake basin had a climate history typical of a summer-dry region, which helps to better define the spatial variability of Holocene climate in the Greater Yellowstone Ecosystem.

Wyoming↗
USGS2002

High-resolution aeromagnetic mapping of volcanic terrain, Yellowstone National Park

High-resolution aeromagnetic data acquired over Yellowstone National Park (YNP) show contrasting patterns reflecting differences in rock composition, types and degree of alteration, and crustal structures that mirror the variable geology of the Yellowstone Plateau. The older, Eocene, Absaroka Volcanic Supergroup, a series of mostly altered, andesitic volcanic and volcaniclastic rocks partially exposed in mountains on the eastern margin of YNP, produces high-amplitude, positive magnetic anomalies, strongly contrasting with the less magnetic, younger, latest Cenozoic, Yellowstone Plateau Group, primarily a series of fresh and variably altered rhyolitic rocks covering most of YNP. The Yellowstone caldera is the centerpiece of the Yellowstone Plateau; part of its boundary can be identified on the aeromagnetic map as a series of discontinuous, negative magnetic anomalies that reflect faults or zones along which extensive hydrothermal alteration is localized. The large-volume rhyolitic ignimbrite deposits of the 0.63-Ma Lava Creek Tuff and the 2.1-Ma Huckleberry Ridge Tuff, which are prominent lithologies peripheral to the Yellowstone caldera, produce insignificant magnetic signatures. A zone of moderate amplitude positive anomalies coincides with the mapped extent of several post-caldera rhyolitic lavas. Linear magnetic anomalies reflect the rectilinear fault systems characteristic of resurgent domes in the center of the caldera. Peripheral to the caldera, the high-resolution aeromagnetic map clearly delineates flow unit boundaries of pre- and post-caldera basalt flows, which occur stratigraphically below the post-caldera rhyolitic lavas and are not exposed extensively at the surface. All of the hot spring and geyser basins, such as Norris, Upper and Lower Geyser Basins, West Thumb, and Gibbon, are associated with negative magnetic anomalies, reflecting hydrothermal alteration that has destroyed the magnetic susceptibility of minerals in the volcanic rocks. Within Yellowstone Lake, which is mostly within the Yellowstone caldera, aeromagnetic lows also are associated with known hydrothermal activity in the lake. Many of the magnetic lows extend beyond the areas of alteration and hot springs, suggesting a more extensive currently active or fossil hydrothermal system than is currently mapped. Steep magnetic gradients, suggesting faults or fractures, bound the magnetic lows. This implies that fractures localize the hot springs. Magnetic gradient trends reflect the mapped Basin and Range structural trends of north and northwest, as well as northeasterly trends that parallel the regional trend of the Snake River Plain and the track of the Yellowstone hot spot which follow the Precambrian structural grain. These trends are found both at small scales such as in hydrothermal basins and at more regional fault scales, which suggests that the regional stress field and reactivated older structures may exert some control on localization of hydrothermal activity. ?? 2002 Elsevier Science B.V. All rights reserved.

Journal of Volcanology and Geothermal Research↗
USGS2020

A newly emerging thermal area in Yellowstone

Yellowstone is a large restless caldera that contains many dynamic thermal areas that are the surface expression of the deeper magmatic system. In 2018, using a Landsat 8 nighttime thermal infrared image, we discovered the emergence of a new thermal area located near Tern Lake on the northeast margin of the Sour Creek dome. A high-spatial-resolution airborne visible image from August 2017 revealed a large (~33,000 m2) area of recently fallen trees, mostly devoid of vegetation, with bright soil, similar to other nearby thermal areas. Field observations in August 2019 confirmed that this was a steam-heated acid-sulfate thermal area, with an arc-shaped zone of hydrothermally altered soil and heated ground, with surface temperatures of 60-80 °C, several steaming fumaroles, and boiling temperatures (93 °C) just beneath the surface. Fallen trees in contact with warm ground were being carbonized, yet there were some cooler areas with new trees growing. Observations of stressed or dying vegetation from archived satellite and airborne remote sensing data going back to 1994 indicated that this thermal area started emerging around 2000. It increased in size slowly until around 2005, when the radiative heat output started measurably increasing. From 2005 to 2012 it grew more rapidly; and from 2012 through 2019 the growth rate slowed and the heat output stabilized. We predict that this stabilizing trend will continue in the coming years. The initial formation of this new thermal area was not clearly linked to any distinct seismic or geodetic events, although the period of rapid growth partly coincided with a period of rapid local uplift, possibly suggesting a causative relationship. The identification of this emerging thermal area illustrates the importance of satellite thermal infrared imaging combined with high-spatial-resolution remote sensing data and field observations for mapping, measuring, and monitoring Yellowstone's thermal areas. It is also an example of the dynamics we expect to observe within large caldera systems like Yellowstone, where changes in the size and distribution of thermal areas are normal and do not indicate an impending eruption nor any significant changes in the broader magmatic system.

Wyoming↗
USGS1970

Sulfur isotope distribution in solfataras, Yellowstone National Park

Sulfur isotope data on hydrogen sulfide, native sulfur, and sulfates from acid hot-spring areas at Yellowstone National Park suggest that hydrogen sulfide oxidizes to sulfur analogically, whereas sulfur undergoes biological oxidation to sulfuric acid. An exception occurs at Mammoth Hot Springs where hydrogen sulfide apparently undergoes biochemical oxidation to sulfur.

Wyoming↗
USGS2006

Volcano and Earthquake Monitoring Plan for the Yellowstone Volcano Observatory, 2006-2015

To provide Yellowstone National Park (YNP) and its surrounding communities with a modern, comprehensive system for volcano and earthquake monitoring, the Yellowstone Volcano Observatory (YVO) has developed a monitoring plan for the period 2006-2015. Such a plan is needed so that YVO can provide timely information during seismic, volcanic, and hydrothermal crises and can anticipate hazardous events before they occur. The monitoring network will also provide high-quality data for scientific study and interpretation of one of the largest active volcanic systems in the world. Among the needs of the observatory are to upgrade its seismograph network to modern standards and to add five new seismograph stations in areas of the park that currently lack adequate station density. In cooperation with the National Science Foundation (NSF) and its Plate Boundary Observatory Program (PBO), YVO seeks to install five borehole strainmeters and two tiltmeters to measure crustal movements. The boreholes would be located in developed areas close to existing infrastructure and away from sensitive geothermal features. In conjunction with the park's geothermal monitoring program, installation of new stream gages, and gas-measuring instruments will allow YVO to compare geophysical phenomena, such as earthquakes and ground motions, to hydrothermal events, such as anomalous water and gas discharge. In addition, YVO seeks to characterize the behavior of geyser basins, both to detect any precursors to hydrothermal explosions and to monitor earthquakes related to fluid movements that are difficult to detect with the current monitoring system. Finally, a monitoring network consists not solely of instruments, but requires also a secure system for real-time transmission of data. The current telemetry system is vulnerable to failures that could jeopardize data transmission out of Yellowstone. Future advances in monitoring technologies must be accompanied by improvements in the infrastructure for data transmission. Overall, our strategy is to (1) maximize our ability to provide rapid assessments of changing conditions to ensure public safety, (2) minimize environmental and visual impact, and (3) install instrumentation in developed areas.

Scientific Investigations Report↗
USGS2012

Is science in danger of sanctifying the wolf?

Historically the wolf ( Canis lupus ) was hated and extirpated from most of the contiguous United States. The federal Endangered Species Act fostered wolf protection and reintroduction which improved the species' image. Wolf populations reached biological recovery in the Northern Rocky Mountains and upper Midwest, and the animal has been delisted from the Endangered Species List in those areas. Numerous studies in National Parks suggest that wolves, through trophic cascades, have caused ecosystems to change in ways many people consider positive. Several studies have been conducted in Yellowstone National Park where wolf interactions with their prey, primarily elk ( Cervus elaphus ), are thought to have caused reduction of numbers or changes in movements and behavior. Some workers consider the latter changes to have led to a behaviorally-mediated trophic cascade. Either the elk reduction or the behavioral changes are hypothesized to have fostered growth in browse, primarily willows ( Salix spp.) and aspen ( Populus spp.), and that growth has resulted in increased beavers ( Castor Canadensis ), songbirds, and hydrologic changes. The wolf's image thus has gained an iconic cachet. However, later research challenges several earlier studies' findings such that earlier conclusions are now controversial; especially those related to causes of browse regrowth. In any case, any such cascading effects of wolves found in National Parks would have little relevance to most of the wolf range because of overriding anthropogenic influences there on wolves, prey, vegetation, and other parts of the food web. The wolf is neither a saint nor a sinner except to those who want to make it so.

Biological Conservation↗
USGS2008

Cosmogenic exposure-age chronologies of Pinedale and Bull Lake glaciations in greater Yellowstone and the Teton Range, USA

We have obtained 69 new cosmogenic 10Be surface exposure ages from boulders on moraines deposited by glaciers of the greater Yellowstone glacial system and Teton Range during the middle and late Pleistocene. These new data, combined with 43 previously obtained 3He and 10Be ages from deposits of the northern Yellowstone outlet glacier, establish a high-resolution chronology for the Yellowstone-Teton mountain glacier complexes. Boulders deposited at the southern limit of the penultimate ice advance of the Yellowstone glacial system yield a mean age of 136??13 10Be ka and oldest ages of ???151-157 10Be ka. These ages support a correlation with the Bull Lake of West Yellowstone, with the type Bull Lake of the Wind River Range, and with Marine Isotope Stage (MIS) 6. End moraines marking the maximum Pinedale positions of outlet glaciers around the periphery of the Yellowstone glacial system range in age from 18.8??0.9 to 16.5??1.4 10Be ka, and possibly as young as 14.6??0.7 10Be ka, suggesting differences in response times of the various ice-cap source regions. Moreover, all dated Pinedale terminal moraines in the greater Yellowstone glacial system post-date the Pinedale maximum in the Wind River Range by ???4-6 kyr, indicating a significant phase relationship between glacial maxima in these adjacent ranges. Boulders on the outermost set and an inner set of Pinedale end moraines enclosing Jenny Lake on the eastern Teton front yield mean ages of 14.6??0.7 and 13.5??1.1 10Be ka, respectively. The outer Jenny Lake moraines are partially buried by outwash from ice on the Yellowstone Plateau, hence their age indicates a major standstill of an expanded valley glacier in the Teton Range prior to the Younger Dryas, followed closely by deglaciation of the Yellowstone Plateau. These new glacial chronologies are indicative of spatially variable regional climate forcing and temporally complex patterns of glacier responses in this region of the Rocky Mountains during the Pleistocene. ?? 2008 Elsevier Ltd. All rights reserved.

Quaternary Science Reviews↗
USGS2022

Response of nutrient limitation to invasive fish suppression: How carcasses and analog pellets alter periphyton

The native Yellowstone Cutthroat Trout ( Oncorhynchus clarkii bouvieri Jordan and Gilbert, 1883) population in Yellowstone Lake, Yellowstone National Park, Wyoming, USA, is in decline because of competition from the introduced, invasive Lake Trout ( Salvelinus namaycush Walbaum in Artedi, 1792). Gillnetting is used to suppress adult Lake Trout; however, methods are being developed to suppress embryos, including adding Lake Trout carcasses and carcass-analog pellets to spawning sites. Decomposing carcasses and analog pellets cause decreased dissolved oxygen concentrations thereby leading to Lake Trout embryo mortality, but the effects of these methods on primary producers are unknown. We deployed in-situ nutrient diffusing substrates (NDS) at 3 spawning sites. The 1 st site was treated with carcasses, the 2 nd site was treated with analog pellets, and a 3 rd lacked treatment (control). To estimate how suppression measures may alter nutrient limitation, we measured algal biomass in 6 NDS amendments at each site: nothing (control), N, P, N + P, ground carcasses, or pulverized analog pellets. We deployed 5 replicates of each amendment at each site before and after treating whole sites. N and P co-limited periphyton before carcasses or analog pellets were added to spawning sites ( p < 0.01); however, nutrients were not limiting after the treatments were added to spawning sites ( p = 0.31–1). Algal biomass was 4× higher after whole-site carcass treatments. In contrast, analog pellets appeared to suppress algal biomass in the amendments (20% of NDS at the control site post-treatment) and in the treatment plot (33% of pre-treatment biomass at analog pellet site). We also measured how individual ingredients in analog pellets altered periphyton biomass, which suggested that vitamin E, estrogen, and soybean oil ingredients reduced the growth of primary producers. Suppression methods may stimulate or reduce algal biomass, depending on the methods used, which could have cascading effects on food webs and potentially reduce the success of the control measures. Estimating how different Lake Trout suppression methods may alter basal resources in the littoral zone of Yellowstone Lake will help natural resource agencies develop effective plans to control invasive predators at early life stages while minimally altering ecosystems.

Wyoming↗
USGS2001

Rapid arsenite oxidation by Thermus aquaticus and Thermus thermophilus: Field and laboratory investigations

Thermus aquaticus and Thermus thermophilus, common inhabitants of terrestrial hot springs and thermally polluted domestic and industrial waters, have been found to rapidly oxidize arsenite to arsenate. Field investigations at a hot spring in Yellowstone National Park revealed conserved total arsenic transport and rapid arsenite oxidation occurring within the drainage channel. This environment was heavily colonized by Thermus aquaticus. In laboratory experiments, arsenite oxidation by cultures of Thermus aquaticus YT1 (previously isolated from Yellowstone National Park) and Thermus thermophilus HB8 was accelerated by a factor of over 100 relative to abiotic controls. Thermus aquaticus and Thermus thermophilus may therefore play a large and previously unrecognized role in determining arsenic speciation and bioavailability in thermal environments.

Environmental Science & Technology↗
USGS2016

Ecological requirements for pallid sturgeon reproduction and recruitment in the Missouri River—Annual report 2013

The Comprehensive Sturgeon Research Project is a multiyear, multiagency collaborative research framework developed to provide information to support pallid sturgeon recovery and Missouri River management decisions. The project strategy integrates field and laboratory studies of pallid sturgeon reproductive ecology, early life history, habitat requirements, and physiology. The project scope of work is developed annually with collaborating research partners and in cooperation with the U.S. Army Corps of Engineers, Missouri River Recovery&mdash;Integrated Science Program. The research consists of several interdependent and complementary tasks that engage multiple disciplines. The research tasks in the 2013 scope of work emphasized understanding reproductive migrations and spawning of adult pallid sturgeon, and hatch and drift of free embryos and larvae. These tasks were addressed in four study sections located in three hydrologically and geomorphologically distinct parts of the Missouri River Basin: the Upper Missouri River downstream from Fort Peck Dam, including downstream reaches of the Milk River, the Lower Yellowstone River, and the Lower Missouri River downstream from Gavins Point Dam. The research is designed to inform management decisions related to channel re-engineering, flow modification, and pallid sturgeon population augmentation on the Missouri River, and throughout the range of the species. Research and progress made through this project are reported to the U.S. Army Corps of Engineers annually. This annual report details the research effort and progress made by the Comprehensive Sturgeon Research Project during 2013.

Missouri River Basin↗
USGS1973

Obsidian hydration dates glacial loading?

Three different groups of hydration rinds have been measured on thin sections of obsidian from Obsidian Cliff, Yellowstone National Park, Wyoming . The average thickness of the thickest (oldest) group of hydration rinds is 16.3 micrometers and can be related to the original emplacement of the flow 176,000 years ago (potassium-argon age). In addition to these original surfaces, most thin sections show cracks and surfaces which have average hydration rind thicknesses of 14.5 and 7.9 micrometers. These later two hydration rinds compare closely in thickness with those on obsidian pebbles in the Bull Lake and Pinedale terminal moraines in the West Yellowstone Basin, which are 14 to 15 and 7 to 8 micrometers thick, respectively. The later cracks are thought to have been formed by glacial loading during the Bull Lake and Pinedale glaciations, when an estimated 800 meters of ice covered the Obsidian Cliff flow.

Wyoming↗