USGS Science⌕ Search

SEARCH · USGS Science

Results for “Studies in Natural Sciences”

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

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

At least 325 records · Page 18Linked to original sources
USGS2018

Clarification of the term “normal material” used for standard atomic weights (IUPAC Technical Report)

The standard atomic weights of the elements apply to normal materials. Since 1984, the Commission on Isotopic Abundances and Atomic Weights (Commission) has defined a normal material as: “The material is a reasonably possible source for this element or its compounds in commerce, for industry or science; the material is not itself studied for some extraordinary anomaly and its isotopic composition has not been modified significantly in a geologically brief period.” The term “a geologically brief period” in this definition is confusing, and confusion can be reduced by revising this definition to the following, which was accepted by the Commission on Isotopic Abundances and Atomic Weights at its meeting in Groningen, Netherlands in September 2017: “ Normal materials include all substances, except (1) those subjected to substantial deliberate, undisclosed, or inadvertent artificial isotopic modification, (2) extraterrestrial materials, and (3) isotopically anomalous specimens, such as natural nuclear reactor products from Oklo (Gabon) or other unique occurrences.”

Pure and Applied Chemistry↗
USGS2019

Phylogeny and foraging mode correspond with thiaminase activity in freshwater fishes: Potential links to environmental factors

Knowledge of the dietary components of fish species is important for understanding their growth, survival, and recruitment. Deficiency in thiamine (vitamin B1) leading to reproductive failure and physiological illness among freshwater fishes has been attributed to thiaminase activity in fish in the Great Lakes and the New York Finger Lakes, but the causes of variation in thiaminase activity among freshwater fishes is unclear. We characterized thiaminase activity in 29 species of freshwater fishes across 7 ray-finned and 1 jawless family. All fish were further categorized by phylogeny, trophic category (trophic level and feeding mode), and native or non-native status to evaluate how ecological processes correspond with thiaminase activity. Thiaminase activity varied significantly across species, families, trophic factors, phylogenetic groups, and sites. Teleosts that were more recently derived had higher thiaminase activity than more basal species. Thiaminase activity was also higher among herbivores than omnivores or carnivores. This trend was clearest in the Cyprinidae family, which had the greatest range in thiaminase activity and a wide range in trophic-level position and trophic categories (herbivores, omnivores, and carnivores). Variation in average thiaminase activity of Spotfin Shiners (Cyprinella spiloptera) among sites within a watershed was correlated with anthropogenic and natural components of land cover. Our study contributes much-needed quantitative ecological information related to thiaminase activity in a suite of fish species that vary in evolutionary history, trophic level, and foraging modes. However, more studies are needed to identify interacting causes of thiaminase variation and examine the implications of these findings on the overall health of aquatic populations and freshwater ecosystems.

Freshwater Science↗
USGS2004

Suwannee river basin and estuary integrated science workshop: September 22-24, 2004 Cedar Key, Florida

In response to the growing number of environmental concerns in the mostly pristine Suwannee River Basin and the Suwannee River Estuary system, the States of Florida and Georgia, the Federal government, and other local organizations have identified the Suwannee River as an ecosystem in need of protection because of its unique biota and important water resources. Organizations with vested interests in the region formed a coalition, the Suwannee Basin Interagency Alliance (SBIA), whose goals are to promote coordination in the identification, management, and scientific knowledge of the natural resources in the basin and estuary. To date, an integrated assessment of the physical, biological, and water resources has not been completed. A holistic, multi-disciplinary approach is being pursued to address the research needs in the basin and estuary and to provide supportive data for meeting management objectives of the entire ecosystem. The USGS is well situated to focus on the larger concerns of the basin and estuary by addressing specific research questions linking water supply and quality to ecosystem function and health across county and state boundaries. A strategic plan is being prepared in cooperation with Federal, State, and local agencies to identify and implement studies to address the most compelling research issues and management questions, and to conduct fundamental environmental monitoring studies. The USGS, Suwannee River Water Management District and the Florida Marine Research Institute are co-sponsoring this scientific workshop on the Suwannee River Basin and Estuary to: Discuss current and past research findings, Identify information gaps and research priorities, and Develop an action plan for coordinated and relevant research activities in the future. This workshop builds on the highly successful basin-wide conference sponsored by the Suwannee Basin Interagency Alliance that was held three years ago in Live Oak, Florida. This years workshop will focus on identifying information needs and priorities and developing partnerships. The USGS is seeking to define the role of the USGS Florida Integrated Science Center (FISC) in conducting integrated research in the Suwannee River Basin, and to establish a cooperative program with other agencies. Participants interested in river, floodplain, springs, estuary, or basin-wide issues are encouraged to attend. Topics for this years workshop include: Water quality and geochemistry: nutrient enrichment, reduction of nutrient loading to ground water, contaminants, and land use, Hydrogeology: interactions among ground water, surface water and ecosystem, modeling, and baseline mapping, Ecosystem dynamics: structure, process, species, and habitats (estuarine, riverine, floodplain, and wetland), and Information management: data sharing, database development, geographic information system (GIS), and basin-wide models.

Open-File Report↗
USGS2006

Near real-time monitoring and mapping of specific conductivity levels across Lake Texoma, USA

A submersible sonde equipped with a specific conductivity probe, linked with a global positioning satellite receiver was developed, deployed on a small boat, and used to map spatial and temporal variations in specific conductivity in a large reservoir. 7,695 sample points were recorded during 8 sampling trips. Specific conductivity ranged from 442 uS/cm to 3,378 uS/cm over the nine-month study. The data showed five statistically different zones in the reservoir: 2 different riverine zones, 2 different riverine transition zones, and a lacustrine zone (the main lake zone). These data were imported to a geographic information system where they were spatially interpolated to generate 8 maps showing specific conductivity levels across the entire surface of the lake. The highly dynamic nature of water quality, due to the widely differing nature of the rivers that flow into the reservoir and the effect of large inflows of fresh water during winter storms is easily captured and visualized using this approach. ?? Springer Science+Business Media, Inc. 2006.

Environmental Monitoring and Assessment↗
USGS2025

Refined mapping of subsurface water ice on Mars to support future missions

Mars has an extensive yet poorly understood cryosphere. Nevertheless, both direct and indirect evidence indicates extensive buried ice across the midlatitudes, including locations where it is presently unstable. While much progress has been made in exploring the processes responsible for ice deposition and preservation during recent climatic fluctuations, a global assessment of the multiple ice reservoirs remains elusive. Motivated by science and the need to find suitable human landing sites, the Mars Subsurface Water Ice Mapping (SWIM) project has developed techniques to map out buried ice. Through integration of all appropriate orbital data sets, the SWIM project produces ∼3 km pixel −1 ice consistency maps over depth ranges of 0–1 m, 1–5 m, and >5 m. In concert with other studies, prior SWIM phases have recognized the uncertainty in our understanding of the geographic and vertical distribution of ice, especially between depths of 1 m and 10 m, creating a push for new ice-prospecting orbital missions, such as the International Mars Ice Mapper mission concept. Here we document the latest SWIM phase, which provides notional targeting maps of the lowest-latitude ice for future missions via a significant improvement in the geomorphic component of our work. The new mapping incorporates both an enhancement in our mapping of geomorphic features and surveys of thermal contraction crack polygons. Our results demonstrate the highly variable nature of the spatial distribution of the shallowest ground ice, with the most equatorward excursions occurring below 30° latitude N/S, locations thought to be out of equilibrium with the current climate.

The Planetary Science Journal↗
USGS2017

Conservation, biodiversity and infectious disease: scientific evidence and policy implications

Habitat destruction and infectious disease are dual threats to nature and people. The potential to simultaneously advance conservation and human health has attracted considerable scientific and popular interest; in particular, many authors have justified conservation action by pointing out potential public health benefits . One major focus of this debate—that biodiversity conservation often decreases infectious disease transmission via the dilution effect—remains contentious. Studies that test for a dilution effect often find a negative association between a diversity metric and a disease risk metric, but how such associations should inform conservation policy remains unclear for several reasons. For one, diversity and infection risk have many definitions, making it possible to identify measures that conform to expectations. Furthermore, the premise that habitat destruction consistently reduces biodiversity is in question, and disturbance or conservation can affect disease in many ways other than through biodiversity change. To date, few studies have examined the broader set of mechanisms by which anthropogenic disturbance or conservation might increase or decrease infectious disease risk to human populations. Due to interconnections between biodiversity change, economics and human behaviour, moving from ecological theory to policy action requires understanding how social and economic factors affect conservation. This Theme Issue arose from a meeting aimed at synthesizing current theory and data on ‘biodiversity, conservation and infectious disease’ (4–6 May 2015). Ecologists, evolutionary biologists, economists, epidemiologists, veterinary scientists, public health professionals, and conservation biologists from around the world discussed the latest research on the ecological and socio-economic links between conservation, biodiversity and infectious disease, and the open questions and controversies in these areas. By combining ecological understanding with insights from the social and economic sciences, the papers in this Theme Issue address the complex relationships, patterns and ecological mechanisms that influence conservation, infectious disease, and the policy options available to protect nature and human health.

Philosophical Transactions of the Royal Society B:↗
USGS2019

Plant and insect herbivore community variation across the Paleocene–Eocene boundary in the Hanna Basin, southeastern Wyoming

Ecosystem function and stability are highly affected by internal and external stressors. Utilizing paleobotanical data gives insight into the evolutionary processes an ecosystem undergoes across long periods of time, allowing for a more complete understanding of how plant and insect herbivore communities are affected by ecosystem imbalance. To study how plant and insect herbivore communities change during times of disturbance, we quantified community turnover across the Paleocene­–Eocene boundary in the Hanna Basin, southeastern Wyoming. This particular location is unlike other nearby Laramide basins because it has an abundance of late Paleocene and Eocene coal and carbonaceous shales and paucity of well-developed paleosols, suggesting perpetually high water availability. We sampled approximately 800 semi-intact dicot leaves from five stratigraphic levels, one of which occurs late in the Paleocene–Eocene thermal maximum (PETM). Field collections were supplemented with specimens at the Denver Museum of Nature & Science. Fossil leaves were classified into morphospecies and herbivore damage was documented for each leaf. We tested for changes in plant and insect herbivore damage diversity using rarefaction and community composition using non-metric multidimensional scaling ordinations. We also documented changes in depositional environment at each stratigraphic level to better contextualize the environment of the basin. Plant diversity was highest during the mid-late Paleocene and decreased into the Eocene, whereas damage diversity was highest at the sites with low plant diversity. Plant communities significantly changed during the late PETM and do not return to pre-PETM composition. Insect herbivore communities also changed during the PETM, but, unlike plant communities, rebound to their pre-PETM structure. These results suggest that insect herbivore communities responded more strongly to plant community composition than to the diversity of species present.

Wyoming↗
USGS1995

Native ranid frogs in California

Many recent declines and extinctions of native amphibians have occurred in certain parts of the world (Wake 1991; Wake and Morowitz 1991). All species of native true frogs have declined in the western United States over the past decade (Hayes and Jennings 1986). Most of these native amphibian declines can be directly attributed to habitat loss or modification, which is often exacerbated by natural events such as droughts or floods (Wake 1991). A growing body of research, however, indicates that certain native frogs are particularly susceptible to population declines and extinctions in habitats that are relatively unmodified by humans (e.g., wilderness areas and national parks in California; Bradford 1991; Fellers and Drost 1993; Kagarise Sherman and Morton 1993). To understand these declines, we must document the current distribution of these species over their entire historical range to learn where they have disappeared. In 1988 the California Department of Fish and Game commissioned the California Academy of Sciences to conduct a 6-year study on the status of the state's amphibians and reptiles not currently protected by the Endangered Species Act. The study's purpose was to determine amphibians and reptiles most vulnerable to extinction and provide suggestions for future research, management, and protection by state, federal, and local agencies (Jennings and Hayes 1993). This article describes the distribution and status of all native true frogs in California as determined by the California Fish and Game study.

California↗
USGS2008

The impacts of mobile fishing gear on seafloor habitats in the Gulf of Maine (Northwest Atlantic): implications for conservation of fish populations

Fishing gear alters seafloor habitats, but the extent of these alterations, and their effects, have not been quantified extensively in the northwest Atlantic. Understanding the extent of these impacts, and their effects on populations of living marine resources, is needed to properly manage current and future levels of fishing effort and fishing power. For example, the entire U.S. side of the Gulf of Maine was impacted annually by mobile fishing gear between 1984 and 1990, based on calculations of area swept by trawl and dredge gear. Georges Bank was imparted three to nearly four times annually during the same period. Studies at three sites in the Gulf of Maine (off Swans Island, Jeffreys Bank, and Stellwagen Bank) showed that mobile fishing gear altered the physical structure (=complexity) of benthic habitats. Complexity was reduced by direct removal of biogenic (e.g., sponges, hydrozoans, bryozoans, amphipod tubes, holothurians, shell aggregates) and‐ sedimentary (e.g., sand waves, depressions) structures. Also, removal of organisms that create.structures (e.g., crabs, scallops) indirectly reduced complexity. Reductions in habitat complexity may lead to increased predation on juveniles of harvested species and ultimately recruitment to the harvestable stock. Because of a lack of reference sites, where use of mobile fishing is prohibited, no empirical studies have yet been conducted on a scale that could demonstrate population level effects of habitat‐management options. If marine fisheries management is to evolve toward an ecosystem or habitat management approach, experiments are required on the effects of habitat change, both anthropogenic and natural.

Maine↗
USGS1967

Infection of the walleye, Stizostedion v. vitreum, of western Lake Erie with Bothriocephalus cuspidatus (Cooper)

In recent years appreciable changes have taken place in the biota and physiochemical conditions in Lake Erie. The accelerated eutrophication of the lake has been accompanied by the near disappearance of several fish species, e.g., blue pike (Stizostedion vitreum glaucum), lake herring (Coregonus artedi), lake trout (Salvelinus namaycush), sauger (Stizostedion canadense), and whitefish (Coregonus clupeaformis). Interest in the biology of the remaining species has increased as means have been sought to preserve their numbers in the lake. This report, which describes the caecal and intestinal parasites of the walleye, Stizostedion vitreum vitreum, is a contribution to the natural history of this fish in western Lake Erie. This study concerns: the type and degree of intestinal parasitic infestations in a single year class of walleyes during their first 3 years of life; seasonal changes in the incidence and maturity of the dominant parasite Bothriocephalus cuspidatus; and the effects of the infestations on the physical condition of the host.

Papers of the Michigan Academy of Science, Arts, a↗
USGS2016

Applying the collective impact approach to address non-native species: A case study of the Great Lakes Phragmites Collaborative

To address the invasion of non-native Phragmites in the Great Lakes, researchers at the U.S. Geological Survey—Great Lakes Science Center partnered with the Great Lakes Commission in 2012 to establish the Great Lakes Phragmites Collaborative (GLPC). The GLPC is a regional-scale partnership established to improve collaboration among stakeholders and increase the effectiveness of non-native Phragmites management and research. Rather than forming a traditional partnership with a narrowly defined goal, the GLPC follows the principles of collective impact to engage stakeholders, guide progress, and align resources to address this complex, regional challenge. In this paper, the concept and tenets of collective impact are described, the GLPC is offered as a model for other natural resource-focused collective impact efforts, and steps for establishing collaboratives are presented. Capitalizing on the interactive collective impact approach, the GLPC is moving toward a broadly accepted common agenda around which agencies and individuals will be able to better align their actions and generate measureable progress in the regional campaign to protect healthy, diverse ecosystems from damage caused by non-native Phragmites .

Biological Invasions↗
USGS2018

Unmanned aerial systems capabilities of the U.S. Geological Survey Woods Hole Coastal and Marine Science Center

Unmanned aerial system (UAS) technology provides a rapid and low-cost solution for mapping coastal environments and assessing short- and long-term changes. The interdisciplinary nature of the data collected and the breadth of applications make UAS technology applicable to multiple scientific investigations. The Aerial Imaging and Mapping (AIM) group at the U.S. Geological Survey (USGS) Woods Hole Coastal and Marine Science Center provides UAS services to scientists to advance the science mission of the Coastal-Marine Hazards and Resources Program. Scientists at the Woods Hole Coastal and Marine Science Center use UASs to acquire imagery of coastal and wetland environments, which is then used to produce detailed topographic and visual reflectance datasets. UAS technology supports the work of geologists, engineers, physical scientists, geographers, and geochemists who study coastal erosion, sediment transport, storm impacts, habitats, biomass, and marsh stability.

Fact Sheet↗
USGS2024

Probabilistic assessment of postfire debris-flow inundation in response to forecast rainfall

Communities downstream of burned steep lands face increases in debris-flow hazards due to fire effects on soil and vegetation. Rapid postfire hazard assessments have traditionally focused on quantifying spatial variations in debris-flow likelihood and volume in response to design rainstorms. However, a methodology that provides estimates of debris-flow inundation downstream of burned areas based on forecast rainfall would provide decision-makers with information that directly addresses the potential for downstream impacts. We introduce a framework that integrates a 24 h lead-time ensemble precipitation forecast with debris-flow likelihood, volume, and runout models to produce probabilistic maps of debris-flow inundation. We applied this framework to simulate debris-flow inundation associated with the 9 January 2018 debris-flow event in Montecito, California, USA. When the observed debris-flow volumes were used to drive the probabilistic forecast model, analysis of the simulated inundation probabilities demonstrates that the model is both reliable and sharp. In the fully predictive model, however, in which debris-flow likelihood and volume were computed from the atmospheric model ensemble's predictions of peak 15 min rainfall intensity, I 15 , the model generally under-forecasted the inundation area. The observed peak I 15 lies in the upper tail of the atmospheric model ensemble spread; thus a large fraction of ensemble members forecast lower I 15 than observed. Using these I 15 values as input to the inundation model resulted in lower-than-observed flow volumes which translated into under-forecasting of the inundation area. Even so, approximately 94 % of the observed inundated area was forecast to have an inundation probability greater than 1 %, demonstrating that the observed extent of inundation was generally captured within the range of outcomes predicted by the model. Sensitivity analyses indicate that debris-flow volume and two parameters associated with debris-flow mobility exert significant influence on inundation predictions, but reducing uncertainty in postfire debris-flow volume predictions will have the largest impact on reducing inundation outcome uncertainty. This study represents a first step toward a near-real-time hazard assessment product that includes probabilistic estimates of debris-flow inundation and provides guidance for future improvements to this and similar model frameworks by identifying key sources of uncertainty.

California↗
USGS2025

Introducing disciplinary perspectives and interdisciplinary possibilities for studying recreational fishers and fisheries

Individuals from many disciplines conduct research to understand the social dimension of recreational fisheries. This diverse inquiry has produced a comprehensive understanding of the behaviours of recreational fishers, the outcomes from fishing, and the relationships among fishers, others, and the natural and human environment. The associated body of research, however, is largely disconnected across disciplines. Our goals here are to help readers understand the similarities and differences among disciplines and to identify opportunities for interdisciplinary-based research on recreational fishers. Before addressing these goals, we begin by answering basic questions: What is a discipline? What are the primary disciplines used to study recreational fishers? And what is the genealogy of research on recreational fishers? Seven key disciplines are then classified by multi-criteria related to both focus and epistemological and methodological approaches. This classification reveals clear connections among: (i) ecological science and resource economics, and to a lesser extent historical ecology; (ii) environmental history and political ecology; and (iii) behavioural economics and social psychology. We next describe and provide possible remedies for barriers that inhibit interdisciplinary research, including different epistemologies, nomenclature, and reward bias. Finally, we highlight opportunities to conduct interdisciplinary research by describing the types of benefits that each discipline can provide when conducting interdisciplinary research on recreational fisheries.

Book chapter↗
USGS1966

Ultraviolet investigations for lunar missions

Preliminary field tests of an active ultraviolet imaging system have shown that it is possible to produce linages of the terrain from distances as great as 75 feet by means of reflected ultraviolet light at wavelengths longer than 3300 A. Minerals that luminesce when exposed to ultraviolet energy have been detected from distances as great as 200 feet. With appropriate design modifications, it may be possible to utilize a similar system in detecting luminescing minerals from greater distances. Also, with a similar system and appropriate auxiliary equipment such as image intensifiers, it may be possible to discriminate between naturally occurring materials on the basis of reflected ultraviolet energy at wavelengths shorter than 3000 A. In this part of the spectrum image contrast for some rock types may exceed that from visible light. Information from these and related ultraviolet spectralanalysis studies may be useful in evaluating data obtained from passive ultraviolet systems in lunar orbit as well as from active systems on the lunar surface.

Advances in Astronautical Sciences↗
USGS2004

Science data in support of environmental health studies in the U.S.-Mexico border region

The border region of the United States and Mexico encompasses a vast and diverse array of physical settings and habitats that include wetlands, deserts, rangeland, mountains, and forests, which are unique in terms of the diversity of their water, mineral, and biological resources. The region is interconnected economically, politically, and socially owing to its binational heritage. In 1995, nearly 11 million people lived immediately adjacent to the border. By one account, that population could more than double by 2020. This rapid population growth and consequent economic development and land-use changes are pushing the limits of environmental sustainability and quality. Infrastructure development has lagged behind the rapid growth of the region, resulting in a shortage of water for municipal, agricultural, and industrial uses. These stressors threaten the quality of life in the region and raise concerns about the interdependence of environmental quality and human health. To allow for continued economic growth while protecting the area’s natural resources and fostering a high quality of life, the United States and Mexico need an improved understanding of the threats posed by these anthropogenic changes. Issues of particular concern include (1) contaminants in ground water, surface water, and biota from agricultural, municipal, and industrial activities; (2) airborne pollutants from fossil-fuel combustion and other activities; (3) contaminants from past and present mining activities and mineral deposits; and (4) pathogens, pharmaceuticals, hormones, and other contaminants released in treated and untreated human and animal wastewaters.

Fact Sheet↗
USGS2003

In praise of mechanistically-rich models

Quantitative models are crucial to almost every area of ecosystem science. They provide a logical structure that guides and informs empirical observations of ecosystem processes. They play a particularly crucial role in synthesizing and integrating our understanding of the immense diversity of ecosystem structure and function. Increasingly, models are being called on to predict the effects of human actions on natural ecosystems. Despite the widespread use of models, there exists intense debate within the field over a wide range of practical and philosophical issues pertaining to quantitative modeling. This book--which grew out of a gathering of leading experts at the ninth Cary Conference--explores those issues. The book opens with an overview of the status and role of modeling in ecosystem science, including perspectives on the long-running debate over the appropriate level of complexity in models. This is followed by eight chapters that address the critical issue of evaluating ecosystem models, including methods of addressing uncertainty. Next come several case studies of the role of models in environmental policy and management. A section on the future of modeling in ecosystem science focuses on increasing the use of modeling in undergraduate education and the modeling skills of professionals within the field. The benefits and limitations of predictive (versus observational) models are also considered in detail. Written by stellar contributors, this book grants access to the state of the art and science of ecosystem modeling.

Book chapter↗
USGS2018

Rapid discovery of SNPs differentiating hatchery steelhead trout from ESA-listed natural-origin steelhead trout using a 57K SNP array

Natural-origin steelhead trout ( Oncorhynchus mykiss (Walbaum, 1792)) in the Pacific Northwest, USA, are threatened by a number of factors including habitat destruction, disease, decline in marine survival, and a potential erosion of genetic viability due to introgression from hatchery strains. Our major goal was to use a recently developed SNP array containing ∼57 000 SNPs to identify a subset of SNPs that differentiate hatchery and natural-origin populations. We analyzed 35 765 polymorphic SNPs in nine populations of steelhead trout sampled from Puget Sound, Washington, USA. We then conducted two outlier tests and found 360 loci that were candidates for divergent selection between hatchery and natural-origin populations (mean F CT = 0.29, maximum = 0.65) and 595 SNPs that were candidates for selection among natural-origin populations (mean F ST = 0.25, maximum = 0.51). Comparisons with a linkage map revealed that two chromosomes (Omy05 and Omy25) contained significantly more outliers than other chromosomes, suggesting that regions on Omy05 and Omy25 may be of adaptive significance. Our results highlight several advantages of the 57 000 SNP array as a tool for population and conservation genomics studies.

British Columbia, Washington↗