SEARCH · Search USGS

Results for “Clear Waters”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources

USGS2007

Reappearance of deepwater sculpin in Lake Ontario: Resurgence or last gasp of a doomed population?

Deepwater sculpin ( Myoxocephalus thompsonii ) were abundant in Lake Ontario in the 1920s and at least common into the 1940s. By the 1960s they were rare and, thereafter, some considered the population extirpated even though a synoptic survey of the lake in 1972 produced three, relatively large (148–165 mm total length, TL), and presumably old, specimens from the northern half of the lake. Deepwater sculpin were absent from annual survey catches in the 1980s and did not reappear until 1996, when three were caught in northern Lake Ontario. Isolated collections of deepwater sculpin continued during 1998–2004. Catches during 1996–2004 included five smaller individuals, 89–118 mm TL. In 2005, catches increased sharply, with 18 deepwater sculpin collected from southern waters and one from northern waters. Moreover, young, small sculpin were dominant in 2005—16 of the 19 sculpins averaged 68 ± 12 mm total length (± 1 s.d.). The young fish observed since 1996 could have originated from reproduction by the small in-lake population, from downstream drift of planktonic larvae from Lake Huron, or both. The presence of juveniles is a clear sign that conditions for survival of young deepwater sculpin are becoming more favorable, perhaps because of reduced abundance of alewife ( Alosa pseudoharengus ), a pelagic planktivore linked to depression of deepwater sculpin in Lake Michigan, and also low abundances of burbot ( Lota lota ) and lake trout ( Salvelinus namaycush ), benthic piscivores.

Journal of Great Lakes Research↗

USGS2024

The National Ocean Biodiversity Strategy

President Biden has been clear that the ocean is central to life on Earth. As he has proclaimed, “the ocean powers millions of jobs; feeds and sustains us; and is a rejuvenating source of inspiration, exploration, and recreation.” The Biden-Harris Administration has worked hard to fulfill the President’s goal to protect and conserve at least 30% of U.S. waters by 2030. The ocean faces increased threats from warming, overfishing, increased acidity, and loss of biodiversity. It is now more important than ever to sustain the many benefits that the ocean, coasts, and Great Lakes provide, including food, a favorable climate, recreation, physical and mental health, and for many, a sense of cultural identity. Ocean life represents an irreplaceable heritage, the foundation of a habitable planet, and a vast trove of resources. Keeping our ocean healthy requires reliable information on the changing status of these living organisms, the drivers of biodiversity change, and options for effectively addressing those drivers. Over 2 million species are estimated to live in the ocean, yet only about 240,000 species have been described by scientists. Most of the ocean’s benefits result from those diverse species interacting with one another and the environment they create. To protect and conserve the ocean, we as a nation need to make better use of existing knowledge and prioritize acquiring new biodiversity knowledge to enable better policy and management decisions. The ability to monitor ocean species and habitats has expanded dramatically over the past decade, with innovations in technology, genomics, taxonomy, big data management and sharing, artificial intelligence, and machine learning. Yet large fractions of the U.S. ocean remain almost unknown. The National Ocean Biodiversity Strategy (strategy) reflects the urgent need to leverage these advances. The goals of this strategy must be guided by the nation’s diverse voices and ways of knowing, in order to maximize effective and equitable stewardship of the ocean’s diverse life and its benefits to people. The strategy is intended as a guiding document for government to advance three overarching goals: ● Goal 1: Drive delivery of ocean biodiversity knowledge at the national scale. Objectives include developing an Implementation Plan for achieving the strategy’s three goals; establishing a coordination mechanism to manage the implementation; and documenting gaps in biodiversity knowledge and the benefits of ocean biodiversity to people and economies. ● Goal 2: Strengthen tools and institutions to deliver ocean biodiversity knowledge. Objectives include establishing a robust information pipeline to support indicators and dynamic maps of ocean biodiversity, from the coasts to the deep sea. This pipeline should include expanded observing systems and comprehensive data management; science and technology solutions to accelerate the availability of biodiversity information; and plans to leverage previous investments to rebuild and expand the nation’s human capital and infrastructure to sustain foundational taxonomy and biodiversity science. ● Goal 3: Protect, conserve, restore, and sustainably use ocean biodiversity. Objectives include expanding the collection, delivery, and use of biodiversity knowledge to inform actions that advance ocean protection, conservation, restoration, and sustainable development. Government should lead in establishing and incentivizing diverse partnerships across scales and sectors to implement those actions and should educate and involve the public to discover and value the nation’s diverse ocean life. Achieving these goals will require commitments across society: new federal and private investments, coordination across sectors to address climate and equity challenges, and engagement of Indigenous Knowledge holders and frontline communities as full partners throughout planning and implementation. The Subcommittee on Ocean Science and Technology (SOST) IWG-Biodiversity will begin developing an Implementation Plan to describe and direct specific actions to implement the strategy. Successful implementation of the strategy will harmonize and expand collection and delivery of timely knowledge on ocean life to all of society. The strategy will also enable evidence-based management and protection of the ocean. Advancing the strategy will build human and institutional capital and partnerships that support both existing mandates and new needs to rebuild and sustain biodiversity, achieve healthy ocean ecosystems, and manage living resources. Implementing the strategy will deliver knowledge for monitoring, modeling, forecasting, and assessments that support food security, public health, and cultural values, and that more effectively protect, conserve, and restore nature.

Report↗

USGS1984

A workshop model simulating fate and effect of drilling muds and cuttings on benthic communities

Oil and gas exploration and production at marine sites has generated concern over potential environmental impacts resulting from the discharge of spent drilling muds and cuttings. This concern has led to a broad array of publicly and privately sponsored research. This report described a cooperative modeling effort designed to focus information resulting from this research through construction of explicit equations that simulate the potential impacts of discharge drilling fluids (muds) and cuttings on marine communities. The model is the result of collaboration among more than 30 scientists. The principal cooperating organizations were the E.S. Environmental Protection Agency, the U.S. Minerals Management Service, the Offshore Operators Committee, and the Alaska Oil and Gas Association. The overall simulation model can be conceptualized as three connected submodels: Discharge and Plume Fate, Sediment Redistribution, and Benthic Community Effects. On each day of simulation, these submodels are executed in sequence, with flows of information between submodels. The Benthic Community Effects submodel can be further divided into sections that calculate mortality due to burial, mortality due to toxicity, mortality due to resuspension disturbance, and growth of the community. The model represents a series of seven discrete 1-m 2 plots at specified distances along a transect in one direction away from a discharge point. It consists of coupled difference equations for which parameter values can easily be set to evaluate different conditions or to examine the sensitivity of output to various assumptions. Sets of parameter values were developed to represent four general cases or scenarios: (1) a shallow (5 m), cold environment with ice cover during a substantial fraction of the year, such as might be encountered in the Beaufort Sea, Alaska; (2) a shallow (20 m), temperate environment, such as might be encountered in the Gulf of Mexico; (3) a deeper (80 m), temperate environment, such as might be encountered in the Gulf of Mexico; and (4) a very deep (1,000 m) environment, such as might be encountered on the Atlantic slope. The focus of the modeling effort was on the connection of a reasonable representation of physical fate to the biological responses of populations, rather than on highly detailed representations of individual processes. For example, the calculations of physical fate are not as detailed as those in the recently published model of Brandsma et al. (1983). The value of the model described herein is in the broad scope of processes that are explicitly represented and linked together. The model cannot be considered to produce reliable predictions of the quantitative impacts of discharged drilling fluids and cuttings on biological populations at a particular site. Limitations of the model in predicting integrated fate and effects can be traced to three general areas: level of refinement of the algorithms used in the model; lack of understanding of the processes determining fate and effects; and parameter and data values. Despite the limitations, several qualitative conclusions concerning both potential impacts and the importance of various remaining data gaps can be drawn from the modeling effort. These include: (1) Simple, unequivocal conclusions about fate and effects across geographical regions and drilling operations are difficult, if not misleading, due to the large amount of variability in characteristics of discharged materials (e.g., oil content and toxicity), discharge conditions (e.g., duration of drilling operations), physical environments (e.g., water depth, current direction, and sediment disturbance regimes), and biological communities (e.g., intrinsic growth rates). Different combinations of these characteristics can result in substantial differences in simulated environmental fate and biological effects. For examples, simulated recovery in some high-energy environments occurs within months after the cessation of discharge operations, even at heavily impacted sites, whereas simulated recover in some low-energy environments takes years at heavily impacted sites. <2) Considerable difficulties remain in the reliable extrapolation of results from laboratory toxicity experiments to predictions of population effects in the field. (3) The volume of material discharged and duration of operations in the production drilling operations simulated by the model are sufficient to produce substantial simulated biological impacts at some plots, both in terms of differences from a control plot during the period of discharge operations, and in terms of the recovery period following the perturbations. Evaluation of the significance of potential effects involves the following factors: • Definition of a specific spatial and temporal reference frame (e.g., What is the natural variation? Is 1 year to be considered a "long" or "short" time? Is 50 m to be considered a "large" or "trivial" distance? • Consideration of rare or unique resources and particularly sensitive biotic assemblages. • Consideration of the potential for long term, cumulative effects. Some of these aspects are clearly beyond the scope of this modeling efforts (e.g., the model does not simulate the long term fate of resuspended material). The model does, however, contain an internal "reference frame" by comparison to simulated behavior at a control plot. The model, in general, simulates substantial "natural" variation at the reference or control plots, both over time, due to sediment disturbance events in medium to high energy environments, and over space, due to geographically varying conditions, such as water depth and current regime.

Report↗

USGS2002

Color-coded contour map of Mars M 25M RKN

NOTES ON BASE This map is based on data from the Mars Orbiter Laser Altimeter (MOLA) (Smith and others, 2001), an instrument on NASA's Mars Global Surveyor (MGS) spacecraft (Albee and others, 2001). The image used for the base of this map represents more than 600 million measurements gathered between 1999 and 2001, adjusted for consistency (Neumann and others, 2001, 2002) and converted to planetary radii. These have been converted to elevations above the areoid as determined from a martian gravity field solution GMM2 (Lemoine and others, 2001), truncated to degree and order 50, and oriented according to current standards (see below). The average accuracy of each point is originally ~100 meters in horizontal position, and ~1 meter in radius (Neumann, 2001). However, the total elevation uncertainty is at least +3 m due to the global error in the areoid (+1.8 meters according to Lemoine and others, 2001) and regional uncertainties in its shape (communication from Neumann, 2002). The measurements were converted into a digital elevation model (DEM) (communication from Neumann, 2002; Neumann and others, 2001; Smith and others, 2001) using Generic Mapping Tools software (Wessel and Smith, 1998), with a resolution of 0.015625 degrees per pixel or 64 pixels per degree. In projection, the pixels are 926.17 meters in size at the equator. PROJECTION The Mercator projection is used between latitudes +57°, with a central meridian at 0° and latitude equal to the nominal scale at 0°. The Polar Stereographic projection is used for the polar regions north of the +55° parallel and south of the –55° parallel with a central meridian set for both at 0°. The adopted equatorial radius is 3,396.19 km (Duxbury and others 2002; Seidelmann and others 2002). COORDINATE SYSTEM The MOLA data were initially referenced to an internally consistent inertial coordinate system, derived from tracking of the MGS spacecraft. By adopting appropriate values for the orientation of Mars as defined by the International Astronomical Union (IAU) and the International Association of Geodesy (IAG) (Seidelmann and others, 2002), these inertial coordinates were converted into the planet-fixed coordinates (longitude and latitude) used on this map. These values include the orientation of the north pole of Mars (including the effects of precession), the rotation rate of Mars, and a value for W0 of 176.630°, where W0 is the angle along the equator to the east, between the 0° meridian and the equator's intersection with the celestial equator at the standard epoch J2000.0 (Seidelmann and others, 2002). This value of W0 was chosen (Duxbury and others, 2002) in order to place the 0° meridian through the center of the small (~500 m) crater Airy-0, located in the crater Airy (de Vaucouleurs and others, 1973; Seidelmann and others, 2002). Longitude increases to the east, and latitude is planetocentric as allowed by IAU/IAG standards (Seidelmann and others, 2002) and in accordance with current NASA and USGS standards (Duxbury and others, 2002). A secondary grid (printed in red) has been added to the map as a reference to the west longitude/planetographic latitude system that is also allowed by IAU/IAG standards (Seidelmann and others, 2002) and has also been used for Mars. The figure adopted to compute this secondary grid is an oblate spheroid with an equatorial radius of 3,396.19 km and a polar radius of 3,376.2 km (Duxbury and others, 2002; Seidelmann and others, 2002). MAPPING TECHNIQUES To create the topographic base image, the original DEM produced by the MOLA team in Simple Cylindrical projection with a resolution of 64 pixels per degree was projected into the Mercator and Polar Stereographic pieces. A shaded relief was generated from each DEM with a sun angle of 30° from horizontal and a sun azimuth of 270°, as measured clockwise from north, and a vertical exaggeration of 100%. Illumination is from the west, which follows a long-standing USGS tradition for planetary maps. This allows for continuity in the shading between maps and quadrangles, and most closely resembles lighting conditions found on imagery. The DEM values were then mapped to a smooth global color look-up table. Note that the chosen color scheme simply represents elevation changes and is not intended to imply anything about surface characteristics (e.g., past or current presence of water or ice). These two files were then merged and scaled to 1:25 million for the Mercator portion and 1:15,196,708 for the two Polar Stereographic portions, with a resolution of 300 dots per inch. The projections have a common scale of 1:13,923,113 at +56° latitude. Contours were created from the DEM at a 1-kilometer interval. Contours for features with a diameter of 3 km or less (features too small for this map scale) were removed. The contours were then simplified by removing points along the contours spaced less than 1 km apart. NOMENCLATURE Names on this sheet are approved by the IAU and have been applied for features clearly visible at the scale of this map. For a complete list of the IAU-approved nomenclature for Mars, see the Gazetteer of Planetary Nomenclature at http://planetarynames.wr.usgs.gov/. Font color was chosen for readability. Names followed by an asterisk are provisionally approved. M 25M RKN: Abbreviation for Mars, 1:25,000,000 series, shaded relief (R), with color (K) and nomenclature (N) (Greeley and Batson, 1990).

Open-File Report↗

USGS2009

Twenty-three years of vegetation change in a fly-ash leachate impacted meadow

1. Blag Slough, located in Indiana Dunes National Lakeshore, has received leachates from nearby fly-ash ponds for 13 years (1967-1980). We have monitored vegetation and sediment of Blag Slough since 1982, two years after the sealing of the fly-ash ponds and one year after the substrate was first exposed. The pH of the soil has increased one order of magnitude from 3.0 to 4.0 over the 23 years (1982-2005). If the pH further increases the solubility of many heavy metals will decrease, except for arsenic. We provide evidence that boron and zinc were bioaccumulating in the leaves of woody plants in 1984. The ratio of leaf concentration and soil concentration of aluminum suggests this element was not bioaccumulating in woody plants in 1984. 2. Soil concentrations of iron, aluminum, arsenic, and strontium were higher nearest the fly-ash ponds in 2005. The southwest corner of Blag Slough and middle position of transect X had the highest elevated levels of these metals and correlated with the occurrence of mixed spikerush association (dominated by Eleocharis olivacea). 3. Only a few exotic species occurred in the Blag Slough. Common reed (Phragmites australis) was among such species that occurred in three large clones. Other exotic species included dandelion (Taraxacum officinale), mullein (Verbascum thapsis), Jerusalem oak goosefoot (Chenopodium botrys), and sheep sorrel (Rumex acetosella). Ruderal species have occurred including thistle (Cirsium spp.), fire weed (Erechtites hieracifolium), and horseweed (Conyza canadensis). While occasional cattail (Typha) have been sampled and mapped in Blag Slough they have never persisted for very long. 4. Species richness leveled off between 1991 and 2005, except for Transect X that had a peak in 1986-7. After an extreme rainfall event in August 18, 1990, Transect V had an average water depth of 0.70 cm, W had 7.1 cm, and X had 26.90 cm. Richness in Transect X declined to a low level in 1990 and 1991 after the extreme flooding event because this transect had the deepest surface water. 5. Typical late successional vegetation associations developed since 1991 include blue joint grass (Calamagrostis canadensis) and buttonbush (Cephalanthus occidentalis), but large areas consist of disturbance-dependent mosaics of rush (Juncus effusus) and other species. The large expanses of woolly sedge (Scirpus cyperinus) that dominated in the 1980’s was replaced by rush. 6. Late-successional associations (Glyceria canadensis and Calamagrostis canadensis) were closer to the wetland edge compared to the other associations after the dewatering. This pattern occurred because wet meadow vegetation persisted at the wetland edge during the period of industrial flooding, but since then these associations expanded greatly into the north half of Blag Slough. 7. Richness, diversity, and floristic quality index (FQI) increased with time at the plot, association, association trajectories, and wetland levels; whereas mean conservatism scores (mean C), the basis of FQI calculation, decreased in time. The high C values, assigned to coastal plain disjunct species and shrubs by judgment of botanists based on their empirical xii experience including regional or state level plant conservation designations are largely responsible for the contradicted trend between FQI and C. Such contradiction highlights a problem with the subjective assignment of C values, and thus the inadequacy of application of FQI in these wetland systems. 8. Occurrence of interveinal clearing in winged sumac (Rhus copallina), late boneset (Eupatorium serotinum), and black dewberry (Rubus occidentalis) suggest a potential phytotoxicity by heavy metals. However, cause-effect relationship between the metals and the plants are yet to be investigated. Nevertheless, boron and zinc accumulation ratios in leaves of woody plants (Betula populifolia, Populus tremuloides, Rhus copallina, and Rubus sp.) in 1984 suggest that boron and zinc were bioaccumulating in those species. Known toxicity effects of aluminum suggest that plants with vein clearing may be experiencing toxic effects of aluminum despite leaf concentrations 58 to 193 ppm. 9. In a greenhouse experiment, rye (Secale cereale) and radish (Raphanus sativus) germinated poorly in the sediments from Blag Slough having high concentrations of heavy metals (ZN, Mn, B, and NH4+) compared to potting soil. However, rye and radish plants grown in Blag Slough soil had shorter shoots and roots, lower root and shoot mass, and lower root to shoot mass ratios compared to plants grown in potting soil. These results suggest some effect of the soil constituents on rye and radish growth. 10. Positive signs in the recovery of Blag Slough include the increase in soil pH, the increasing dominance of late successional grasses, and the establishment of wetland zonation relative to seasonal water depth. Some areas of Blag Slough near the fly-ash ponds that continue to have high concentrations of heavy metals continue to be devoid of vegetation or are dominated by early successional species such as green spikerush. Localized heavy metal concentrations, evidence for zinc and boron bioaccumulation in 1984, vein clearing that persists today, effects of soil on rye and racish growth, and slow succession in the southern portion of Blag Slough suggest further toxicity study is necessary to better assess the impacts on this wetland ecosystem and identify restoration actions.

Indiana↗

USGS2018

Biocrusts: The living skin of the Earth

Biological soil crusts (biocrusts) form a “living skin” at the soil surface in many low productivity ecosystems around the world including water- and cold-limited environments, and early successional seres (Belnap et al. 2003). They may be composed of any configuration of soil surface-dwelling cyanobacteria, eukaryotic algae, lichens, mosses or liverworts, and support assemblages of decomposers and a faunal food web (Belnap et al. 2003). These soil surface communities have global relevance, as it has been recently estimated that they cover about 12% of the terrestrial surface currently (Rodriguez-Caballero et al. 2018). Biocrust communities are perhaps an ideal subject for the journal Plant and Soil, because they are simultaneously plant-like, due to their dominance by autotrophs, yet biocrusts are also clearly a physical feature of the soil given that component organisms are enmeshed in, adherent to, or otherwise in direct contact with the soil surface. The activity of the organisms is what engineers the well-aggregated thin layer at the soil surface that we recognize as a biocrust (Belnap et al. 2003). The contributions of biocrusts to ecosystem function has fueled much research interest, initially in the observation of biocrusts’ soil aggregating and erosion-resisting nature, and later as a multifunctional, globally-relevant ecosystem element instrumental in: 1. building or otherwise altering soil nutrient stocks through N-fixation (Elbert et al. 2012), dust trapping (Reynolds et al. 2001) and nutrient cycling (Strauss et al. 2012), 2. influencing hydrological properties of soil such as the water balance (Chamizo et al. 2016), and 3. The thermal energy balance of the ecosystem (Coradeau et al. 2016, Rutherford et al. 2017).

Plant and Soil↗

USGS1984

Transport and concentration controls for chloride, strontium, potassium and lead in Uvas Creek, a small cobble-bed stream in Santa Clara County, California, U.S.A.: 1. Conceptual model

Stream sediments adsorb certain solutes from streams, thereby significantly changing the solute composition; but little is known about the details and rates of these adsorptive processes. To investigate such processes, a 24-hr. injection of a solution containing chloride, strontium, potassium, sodium and lead was made at the head of a 640-m reach of Uvas Creek in west-central Santa Clara County, California. Uvas Creek is a cobble-bed pool-and-riffle stream draining the eastern slopes of the Santa Cruz Mountains. By September 12, 1973, after a long dry season, Uvas Creek had a low (0.0215 m 3 s −1 average) flow which varied diurnally, from 0.018 to 0.025 m 3 s −1 . Because stream discharge varied while the injection rate was constant, the concentration of tracers (injected solutes), after mixing in the stream, varied inversely with discharge. Chloride, a nonreactive solute, served as a tracer of water movement. Analysis of extensive chloride concentration data at five sites below the injection point during and after the injection demonstrated that there was considerable underflow of water through the stream gravels; however, the extent of underflow varied greatly within the study reach. Pre-injection water, displaced by tracer-laden water percolating through the gravels, diluted tracers in the stream channel, giving the mistaken impression of groundwater inflow at some points. Accurate measurement of total discharge in such streams requires prolonged tracer injection unless a reach can be found where underflow is negligible. Strontium and potassium were adsorbed by the bed sediments to a moderate extent and lead was strongly adsorbed. A high proportion of these metals could be removed by adsorption from percolating underflow because of extensive and intimate contact with bed sediments. After channel clearing following injection cutoff, 51% of the added strontium and 96% of the lead remained in the study reach, whereas only 19% of the chloride remained. Packets of sized sediment, placed in the stream before the experiment and withdrawn during and after the injection, indicated that the strontium absorbed on the 0.42–0.50-mm size sediment appeared to achieve near equilibrium with dissolved strontium within less than 2 hr. whereas 3.4–4.0-mm grains had not reached that stage after 24 hr. The cation-exchange capacity (CEC) of the sediments shows a “bimodal” distribution with grain size. Largest values are in the finest sizes, lower values in the fine-to-medium sand-size range, intermediate values in the coarse- to very coarse-grained sand, and decreasing values with size above very coarse-grained sand. This considerable exchange capacity in coarse-sand to granule-size particles means that a streambed, that has not been infilled with fines to reduce permeability, can be highly reactive and accessible throughout a rather thick sediment layer and hence have a large and available reactive capacity. As stream discharge increases from low flow, the ratio of underflow to channel flow should decrease rapidly with resultant diminution in percent of solutes sorbed within a particular stream reach.

California↗

USGS2013

Gonadal abnormalities in frogs (Lithobates spp.) collected from managed wetlands in an agricultural region of Nebraska, USA

Nebraska's Rainwater Basin (RWB) provides important wetland habitat for North American migratory birds. Concern exists that pesticide and nutrient runoff from surrounding row-crops enters wetlands degrading water quality and adversely affecting birds and wildlife. Frogs may be especially vulnerable. Plains leopard (Lithobates blairi) metamorphs from RWB wetlands with varying concentrations of pesticides were evaluated for a suite of biomarkers of exposure to endocrine active chemicals. Froglets had ovarian dysgenesis, high rates of testicular oocytes, and female-biased sex ratios however, there was no clear statistical association between pesticide concentrations and biomarkers. Data interpretation was hindered because timing and duration of exposures were unknown and due to an incomplete understanding of L. blairi sexual development. Emphasis is on describing the complex developmental biology of closely-related leopard frogs, how this understanding can explain RWB L. blairi anomalies, and the need for sampling at the appropriate life stage.

Nebraska↗

USGS2006

The rocks of Gusev Crater as viewed by the Mini-TES instrument

The Miniature Thermal Emission Spectrometer (Mini-TES) on board the Mars Exploration Rover Spirit is part of a payload designed to investigate whether a lake once existed in Gusev Crater. Mini-TES has observed hundreds of rocks along the rover's traverse into the Columbia Hills, yielding information on their distribution, bulk mineralogy, and the potential role of water at the site. Although dust in various forms produces contributions to the spectra, we have established techniques for dealing with it. All of the rocks encountered on the plains traverse from the lander to the base of the Columbia Hills share common spectral features consistent with an olivine-rich basaltic rock known as Adirondack Class. Beginning at the base of the West Spur of the Columbia Hills and across its length, the rocks are spectrally distinct from the plains but can be grouped into a common type called Clovis Class. These rocks, some of which appear as in-place outcrop, are dominated by a component whose spectral character is consistent with unaltered basaltic glass despite evidence from other rover instruments for significant alteration. The northwest flank of Husband Hill is covered in float rocks known as Wishstone Class with spectral features that can be attributed uniquely to plagioclase feldspar, a phase that represents more than half of the bulk mineralogy. Rare exceptions are three classes of basaltic "exotics" found scattered across Husband Hill that may represent impact ejecta and/or float derived from local intrusions within the hills. The rare outcrops observed on Husband Hill display distinctive spectral characteristics. The outcrop called Peace shows a feature attributable to molecular bound water, and the outcrop that hosts the rock called Watchtower displays a dominant basaltic glass component. Despite evidence from the rover's payload for significant alteration of some of the rocks, no unambiguous detection of crystalline phyllosilicates or other secondary silicates has been observed by Mini-TES. The mineralogical results supplied by Mini-TES provide no clear evidence that a lake once existed in Gusev Crater. Copyright 2006 by the American Geophysical Union.

Journal of Geophysical Research E: Planets↗

USGS1982

The lanthanides and yttrium in minerals of the apatite group; a review

More than 1000 analyses have been tabulated of the distribution of the lanthanides and yttrium in minerals of the apatite group, recalculated to atomic percentages. Average compositions have been calculated for apatites from 14 types of rocks. These show a progressive change of composition from apatites of granitic pegmatites, highest in the heavy lanthanides and yttrium, to those from alkalic pegmatites, highest in the light lanthanides and lowest in yttrium. This progression is clearly shown in plots of S (= at % La+Ce+Pr) vs the ratio La/Nd and of S vs the ratio 100Y/(Y+Ln), where Ln is the sum of the lanthanides. Apatites of sedimentary phosphorites occupy a special position, being relatively depleted in Ce and relatively enriched in yttrium and the heavy lanthanides, consequences of deposition from sea water. Apatites associated with iron ores are close in composition to apatites of carbonatites, alkalic ultramafic, and ultramafic rocks, being enriched in the light lanthanides and depleted in the heavy lanthanides. Their compositions do not support the hypothesis of Parak that the Kiruna-type ores are of sedimentary origin. Table 9 and Figures 1-3 show the dependence of lanthanide distribution on the nature of the host rock. Although a given analysis of the lanthanides does not unequivocally permit certain identification of the host rock, it can indicate a choice of highly probable host rocks.

Open-File Report↗

USGS1983

Man-induced channel adjustment in Tennessee streams

Channel modifications in Tennessee, particularly in the western part, have led to large-scale instabilities in the channelized rivers and may have contributed to several bridge failures. These modifications, together with land-use practices, led to downcutting, headward erosion, downstream aggradation, accelerated scour, and bank instabilities. Changes in gradient by channel straightening caused more severe channel response than did dredging or clearing. Large-scale changes continue to occur in all the channelized rivers: the Obion River, its forks, and the South Fork Forked Deer River. However, the non-channelized Hatchie River in west Tennessee not only withstood the natural stresses imposed by the wet years of 1973 to 1975 but continues to exhibit characteristics of stability. Water-surface slope, the primary dependent variable, proved to be a sensitive and descriptive parameter useful in determining channel adjustment. Adjustments to man-induced increases in channel-slope are described by inverse exponential functions of the basic form S=ae(-b(t)); where ' S ' is some function describing channel-slope, ' t ' is the number of years since completion of channel work, and ' a ' and ' b ' are coefficients. Response times for the attainment of ' equilibrium ' channel slopes are a function of the magnitude and extent of the imposed modifications. The adjusted profile gradients attained by the streams following channelization are similar to the predisturbed profile gradients, where no alteration to channel length was made. Where the channels were straightened by constructing cut-offs, thus shortening channel length, then slope adjustments (reduction) proceed past the predisturbed profile gradients, to new profiles with lower gradients. (USGS)

Water-Resources Investigations Report↗

USGS2006

Predicting crappie recruitment in Ohio reservoirs with spawning stock size, larval density, and chlorophyll concentrations

Stock-recruit models typically use only spawning stock size as a predictor of recruitment to a fishery. In this paper, however, we used spawning stock size as well as larval density and key environmental variables to predict recruitment of white crappies Pomoxis annularis and black crappies P. nigromaculatus, a genus notorious for variable recruitment. We sampled adults and recruits from 11 Ohio reservoirs and larvae from 9 reservoirs during 1998-2001. We sampled chlorophyll as an index of reservoir productivity and obtained daily estimates of water elevation to determine the impact of hydrology on recruitment. Akaike's information criterion (AIC) revealed that Ricker and Beverton-Holt stock-recruit models that included chlorophyll best explained the variation in larval density and age-2 recruits. Specifically, spawning stock catch per effort (CPE) and chlorophyll explained 63-64% of the variation in larval density. In turn, larval density and chlorophyll explained 43-49% of the variation in age-2 recruit CPE. Finally, spawning stock CPE and chlorophyll were the best predictors of recruit CPE (i.e., 74-86%). Although larval density and recruitment increased with chlorophyll, neither was related to seasonal water elevation. Also, the AIC generally did not distinguish between Ricker and Beverton-Holt models. From these relationships, we concluded that crappie recruitment can be limited by spawning stock CPE and larval production when spawning stock sizes are low (i.e., CPE , 5 crappies/net-night). At higher levels of spawning stock sizes, spawning stock CPE and recruitment were less clearly related. To predict recruitment in Ohio reservoirs, managers should assess spawning stock CPE with trap nets and estimate chlorophyll concentrations. To increase crappie recruitment in reservoirs where recruitment is consistently poor, managers should use regulations to increase spawning stock size, which, in turn, should increase larval production and recruits to the fishery.

North American Journal of Fisheries Management↗

USGS2000

Bottom currents and sediment transport in Long Island Sound: A modeling study

A high resolution (300-400 m grid spacing), process oriented modeling study was undertaken to elucidate the physical processes affecting the characteristics and distribution of sea-floor sedimentary environments in Long Island Sound. Simulations using idealized forcing and high-resolution bathymetry were performed using a three-dimensional circulation model ECOM (Blumberg and Mellor, 1987) and a stationary shallow water wave model HISWA (Holthuijsen et al., 1989). The relative contributions of tide-, density-, wind- and wave-driven bottom currents are assessed and related to observed characteristics of the sea-floor environments, and simple bedload sediment transport simulations are performed. The fine grid spacing allows features with scales of several kilometers to be resolved. The simulations clearly show physical processes that affect the observed sea-floor characteristics at both regional and local scales. Simulations of near-bottom tidal currents reveal a strong gradient in the funnel-shaped eastern part of the Sound, which parallels an observed gradient in sedimentary environments from erosion or nondeposition, through bedload transport and sediment sorting, to fine-grained deposition. A simulation of estuarine flow driven by the along-axis gradient in salinity shows generally westward bottom currents of 2-4 cm/s that are locally enhanced to 6-8 cm/s along the axial depression of the Sound. Bottom wind-driven currents flow downwind along the shallow margins of the basin, but flow against the wind in the deeper regions. These bottom flows (in opposition to the wind) are strongest in the axial depression and add to the estuarine flow when winds are from the west. The combination of enhanced bottom currents due to both estuarine circulation and the prevailing westerly winds provide an explanation for the relatively coarse sediments found along parts of the axial depression. Climatological simulations of wave-driven bottom currents show that frequent high-energy events occur along the shallow margins of the Sound, explaining the occurrence of relatively coarse sediments in these regions. Bedload sediment transport calculations show that the estuarine circulation coupled with the oscillatory tidal currents result in a net westward transport of sand in much of the eastern Sound. Local departures from this regional westward trend occur around topographic and shoreline irregularities, and there is strong predicted convergence of bedload transport over most of the large, linear sand ridges in the eastern Sound, providing a mechanism which prevents their decay. The strong correlation between the near-bottom current intensity based on the model results and the sediment response, as indicated by the distribution of sedimentary environments, provides a framework for predicting the long-term effects of anthropogenic activities.

New York↗

USGS1973

Transit losses and travel times for reservoir releases, upper Arkansas River Basin, Colorado

Factors influencing reservoir releases were analyzed for the upper reach of the Arkansas River in Colorado. The time of travel of releases from Twin Lakes Reservoir to Colorado Canal, a distance of 175 miles, ranges from 29 to 69 hours depending on the antecedent flow of the Arkansas River. Travel time of releases from Turquoise Lake is 42 hours more and travel time of releases from Clear Creek Reservoir is 12 hours less than for the Twin Lakes Reservoir to Colorado Canal reach. At the Colorado Canal, the streamflow hydrographs resulting from upstream reservoir releases are modified by channel and bank storage, inadvertent diversions, and evapotranspiration. During an average reservoir release of about 450 cubic feet per second for about 12 days, the released water arriving at the Colorado Canal is reduced by about 7 percent due to bank storage, by about 8 percent due to inadvertent diversions, and by about 1 percent due to evaporation. All release water in channel storage arrives at the Colorado Canal headgate during the release recession soon enough to be diverted and does not cause a loss. Transpiration losses due to bank storage are assumed to be negligible. This total average transportation Loss of 16 percent can vary from about 6 to 28 percent due to the antecedent river conditions, the amount and duration of the reservoir release, and the time of year the release occurs.

Colorado↗

USGS2009

Population Dynamics of Adult Lost River (Deltistes luxatus) and Shortnose (Chasmistes brevirostris) Suckers in Clear Lake Reservoir, California, 2006-08

We report results from ongoing research into the population dynamics of endangered Lost River and shortnose suckers in Clear Lake Reservoir, California. Results are included for sampling that occurred from fall 2006 to spring 2008. We summarize catches and passive integrated transponder tagging efforts from trammel net sampling in fall 2006 and fall 2007, and report on detections of tagged suckers on remote antennas in the primary spawning tributary, Willow Creek, in spring 2007 and spring 2008. Results from trammel net sampling were similar to previous years, although catches of suckers in fall 2006 were lower than in 2007 and past years. Lost River and shortnose suckers combined made up about 80 percent of the sucker catch in each year, and more than 2,000 new fish were tagged across the 2 years. Only a small number of the suckers captured in fall sampling were recaptures of previously tagged fish, reinforcing the importance of remote detections of fish for capture-recapture analysis. Detections of tagged suckers in Willow Creek were low in spring 2007, presumably because of low flows. Nonetheless, the proportions of tagged fish that were detected were reasonably high and capture-recapture analyses should be possible after another year of data collection. Run timing for Lost River and shortnose suckers was well described by first detections of individuals by antennas in Willow Creek, although we may not have installed the antennas early enough in 2008 to monitor the earliest portion of the Lost River sucker migration. The duration and magnitude of the spawning runs for both species were influenced by flows and water temperature. Flows in Willow Creek were much higher in 2008 than in 2007, and far more detections were recorded in 2008 and the migrations were more protracted. In both years and for both species, migrations began in early March at water temperatures between 5 and 6 deg C and peaks were related to periods of increasing water temperature. The sex ratio of Lost River suckers detected in Willow Creek was skewed toward males, despite consistently more females having been tagged in fall sampling. This pattern indicates that some tagged female Lost River suckers may be spawning elsewhere in the system, and we intend to investigate this possibility to verify or alter the representativeness of our spring monitoring. Length frequency analysis of fall trammel net catches showed that the populations of both species in Clear Lake Reservoir have undergone major demographic transitions during the last 15 years. In the mid-1990s, the populations were dominated by larger fish and showed little evidence of recent recruitment. These larger fish apparently disappeared in the late 1990s and early 2000s, and the populations are now dominated by fish that recruited into the adult populations in the late 1990s. The length frequencies from the last 4 years provide evidence of consistent recruitment into the Lost River sucker population, but provide no such evidence for the shortnose sucker population. Overall, annual growth rates for both species in Clear Lake were 2-4 times greater than growth rates for conspecifics in Upper Klamath Lake. However, little or no growth occurred for either species in Clear Lake between 2006 and 2007. Based on available evidence, we are unable to fully explain differences in growth rates between systems or among years within Clear Lake.

Open-File Report↗

USGS1987

Presence and potential significance of aromatic-ketone groups in aquatic humic substances

Aquatic humic- and fulvic-acid standards of the International Humic Substances Society were characterized, with emphasis on carbonyl-group nature and content, by carbon-13 nuclear-magnetic-resonance spectroscopy, proton nuclear-magnetic-resonance spectroscopy, and infrared spectroscopy. After comparing spectral results of underivatized humic and fulvic acids with spectral results of chemically modified derivatives, that allow improved observation of the carbonyl group, the data clearly indicated that aromatic ketone groups comprised the majority of the carbonyl-group content. About one ketone group per monocyclic aromatic ring was determined for both humic and fulvic acids. Aromatic-ketone groups were hypothesized to form by photolytic rearrangements and oxidation of phenolic ester and hydrocarbon precursors; these groups have potential significance regarding haloform formation in water, reactivity resulting from active hydrogen of the methyl and methylene adjacent to the ketone groups, and formation of hemiketal and lactol structures. Aromatic-ketone groups also may be the point of attachment between aliphatic and aromatic moieties of aquatic humic-substance structure.

Georgia↗

USGS2017

Nearly 400 million people are at higher risk of schistosomiasis because dams block the migration of snail-eating river prawns

Dams have long been associated with elevated burdens of human schistosomiasis, but how dams increase disease is not always clear, in part because dams have many ecological and socio-economic effects. A recent hypothesis argues that dams block reproduction of the migratory river prawns that eat the snail hosts of schistosomiasis. In the Senegal River Basin, there is evidence that prawn populations declined and schistosomiasis increased after completion of the Diama Dam. Restoring prawns to a water-access site upstream of the dam reduced snail density and reinfection rates in people. However, whether a similar cascade of effects (from dams to prawns to snails to human schistosomiasis) occurs elsewhere is unknown. Here, we examine large dams worldwide and identify where their catchments intersect with endemic schistosomiasis and the historical habitat ranges of large, migratory Macrobrachium spp. prawns. River prawn habitats are widespread, and we estimate that 277–385 million people live within schistosomiasis-endemic regions where river prawns are or were present (out of the 800 million people who are at risk of schistosomiasis). Using a published repository of schistosomiasis studies in sub-Saharan Africa, we compared infection before and after the construction of 14 large dams for people living in: (i) upstream catchments within historical habitats of native prawns, (ii) comparable undammed watersheds, and (iii) dammed catchments beyond the historical reach of migratory prawns. Damming was followed by greater increases in schistosomiasis within prawn habitats than outside prawn habitats. We estimate that one third to one half of the global population-at-risk of schistosomiasis could benefit from restoration of native prawns. Because dams block prawn migrations, our results suggest that prawn extirpation contributes to the sharp increase of schistosomiasis after damming, and points to prawn restoration as an ecological solution for reducing human disease.

Philosophical Transactions of the Royal Society B:↗

USGS1990

Determination of hydraulic properties in the vicinity of a landfill near Antioch, Illinois

A hydrogeologic investigation was conducted in and around a landfill near Antioch, Illinois, in December 1987. The investigation consisted, in part, of an aquifer test that was designed to determine the hydraulic connection between the hydrogeologic units in the area. The hydrogeologic units consist of a shallow, unconfined, sand and gravel aquifer of variable thickness that overlies an intermediate confining unit of variable thickness composed predominantly of till. Underlying the till is a deep, confined, sand and gravel aquifer that serves as the water supply for the village of Antioch. The aquifer test was conducted in the confined aquifer. Aquifer-test data were analyzed using the Hantush and Jacob method for a leaky confined aquifer with no storage in the confining unit. Calculated transmissivity of the confined aquifer ranged from 1.96x10^4 to 2.52x10^4 foot squared per day and storativity ranged from 2.10x10^-4 to 8.71x10^-4. Leakage through the confining unit ranged from 1.29x10^-4 to 7.84x10^-4 foot per day per foot, and hydraulic conductivity of the confining unit ranged from 3.22x10^-3 to 1.96x10^-2 foot per day. The Hantush method for analysis of a leaky confined aquifer with storage in the confining unit also was used to estimate aquifer and confining-unit properties. Transmissivity and storativity values calculated using the Hantush method are in good agreement with the values calculated from the Hantush and Jacob method. Properties of the confining unit were estimated using the ratio method of Neuman and Witherspoon. The estimated diffusivity of the confining unit ranged from 50.36 to 68.13 feet squared per day, A value for the vertical hydraulic conductivity of the confining unit calculated from data obtained using both the Hantush and the Neuman and Witherspoon methods was within the range of values calculated by the Hantush and Jacob method. The aquifer-test data clearly showed that the confining unit is hydraulically connected to the confined aquifer. The aquifer-test data also indicated that the unconfined aquifer becomes hydraulically connected to the deep sand and gravel aquifer within 24 hours after the start of pumping in the confined aquifer.

Water-Resources Investigations Report↗