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At least 541 records · Page 30Linked to original sources
USGS2019

Lava lake thermal pattern classification using self organizing maps and relationships to eruption processes at Kilauea Volcano, Hawaii

Kīlauea Volcano’s active summit lava lake poses hazards to downwind residents and over 1.6 million Hawai‘i Volcanoes National Park visitors each year. The lava lake surface is dynamic; crustal plates separated by incandescent cracks move across the lake as magma circulates below. We hypothesize that these dynamic thermal patterns are related to changes in other volcanic processes, such that sequences of thermal images may provide information about eruption parameters that are sometimes difficult to measure. The ability to learn about current gas emissions and seismic activity from a remote thermal time-lapse camera would be beneficial when conditions are too hazardous for field measurements. We apply a machine learning algorithm called self-organizing maps (SOM) to thermal infrared time-lapse images of the lava lake collected hourly over 23 April – 21 October 2013 (n=4354). The SOM algorithm can take thousands of seemingly different images, each representing the spatial distribution of relative temperature across the lava lake surface, and group them into clusters based on their similarities. We then relate the resulting clusters to sulfur dioxide emissions and seismic tremor to characterize ties between the SOM classification and different emplacement conditions. The SOM classification results are highly sensitive to the normalization method applied to the input images. The standard pixel-by-pixel normalization method yields a cluster of images defined by the highest observed SO2 emission levels, elevated surface temperatures, and a high proportion of cracks between crustal plates. When lava lake surface patterns are isolated by minimizing the effect of temperature variation between images, relationships with seismic tremor activity emerge, revealing an “intense spatter” cluster, characterized by unstable, broken-up crustal plate patterns on the lava lake surface. This proof of concept study provides a basis for extending the SOM classification method to hazard forecasting and real-time volcanic monitoring applications, as well as comparative studies at other lava lakes.

Hawaii↗
USGS1989

Habitat area requirements of breeding forest birds of the middle Atlantic states

Conservation of birds requires an understanding of their nesting requirements, including area as well as structural characteristics of the habitat. Previous studies have shown that many neotropical migrant bird species seem to depend on extensive forested areas, but the specific area requirements of individual species have not been clarified sufficiently to aid in design and management of effective preserves. For this 5-year study, bird and vegetation data were obtained at 469 points in forests ranging in area from 0.1 ha to more than 3,000 ha in Maryland and adjacent states. Data were analyzed first by stepwise regression to identify habitat factors that had the greatest influence on relative abundance of each bird species. In the relatively undisturbed mature forests studied, degree of isolation and area were significant predictors of relative abundance for more bird species than were any habitat variables. For species for which forest area was a significant predictor of abundance, we used logistic regression to examine the relationship between forest area and the probability of detecting the species. In managing forest lands for wildlife, top priority should go toward providing for the needs of area-sensitive or rare species rather than increasing species diversity per se. Avian species that occur in small and disturbed forests are generalists that are adapted to survival under edge conditions and need no special assistance from man. Forest reserves with thousands of hectares are required to have the highest probability of providing for the least common species of forest birds in a region. However, if preservation of large contiguous forest tracts is not a realistic option, results of this study suggest 2 alternative approaches. First, if other habitat attributes also are considered, smaller forests may provide suitable breeding sites for relatively rare species. Second, smaller tracts in close proximity to other forests may serve to attract or retain area-sensitive species.

Book↗
USGS1998

Trace fossil analysis of lacustrine facies and basins

Two ichnofacies are typical of lacustrine depositional systems. The Scoyenia ichnofacies characterizes transitional terrestrial/nonmarine aquatic substrates, periodically inundated or desiccated, and therefore is commonly present in lake margin facies. The Mermia ichnofacies is associated with well oxygenated, permanent subaqueous, fine-grained substrates of hydrologically open, perennial lakes. Bathymetric zonations within the Mermia ichnofacies are complicated by the wide variability of lacustrine systems. Detected proximal-distal trends are useful within particular lake basins, but commonly difficult to extrapolate to other lakes. Other potential ichnofacies include the typically marine Skolithos ichnofacies for high-energy zones of lakes and substrate-controlled, still unnamed ichnofacies, associated to lake margin deposits. Trace fossils are useful for sedimentologic analysis of event beds. Lacustrine turbidites are characterized by low-diversity suites, reflecting colonization by opportunistic organisms after the turbidite event. Underflow current beds record animal activity contemporaneous with nearly continuous sedimentation. Ichnologic studies may also help to distinguish between marine and lacustrine turbidites. Deep-marine turbidites host the Nereites ichnofacies that consists of high diversity of ornate grazing traces and graphoglyptids, recording highly specialized feeding strategies developed to solve the problem of the scarcity of food in the deep sea. Deep lacustrine environments contain the Mermia ichnofacies, which is dominated by unspecialized grazing and feeding traces probably related to the abundance and accessibility of food in lacustrine systems. The lower diversity of lacustrine ichnofaunas in comparison with deep-sea assemblages more likely reflects lower species diversity as a consequence of less stable conditions. Increase of depth and extent of bioturbation through geologic time produced a clear signature in the ichnofabric record of lacustrine facies. Paleozoic lacustrine ichnofaunas are typically dominated by surface trails with little associated bioturbation. During the Mesozoic, bioturbation depth was higher in lake margin facies than in fully lacustrine deposits. While significant degrees of bioturbation were attained in lake margin facies during the Triassic, major biogenic disruption of primary bedding in subaqueous lacustrine deposits did not occur until the Cretaceous.

Palaeogeography, Palaeoclimatology, Palaeoecology↗
USGS2023

60 years and beyond of Reviews of Geophysics

Reviews of Geophysics is an AGU journal, first established in February 1963. It is a hybrid open access invitation-only journal that publishes comprehensive review articles across various disciplines within the Earth and Space Sciences. The selection criteria are rigorous and many submissions are declined without review. The journal is the highest ranked in the fields of Geochemistry and Geophysics, with a high Journal Impact Factor (JIF 2021 = 24.9), which is indicative of its high visibility and influence within the scientific community. The journal's published review papers, beyond a mere summary of literature, provide crucial context for current work, and establish the framework for comprehensive understanding of research progress, challenges, and interconnections between different communities, so that research may be appreciated by a broad audience. We emphasize the importance of publishing studies that provide a comprehensive overview and synthesis of the current state of knowledge in a field, especially in the case of geophysics, where knowledge is rapidly developing, increasing and becoming more specialized.

Reviews of Geophysics↗
USGS2015

Concentration and retention of Toxoplasma gondii oocysts by marine snails demonstrate a novel mechanism for transmission of terrestrial zoonotic pathogens in coastal ecosystems

The parasite T oxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T . gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T . gondii by marine snails in laboratory aquaria, and to test for natural T . gondii contamination in field-collected snails. Following exposure to T . gondii -containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T . gondii oocysts detected in snail faeces and tissues by microscopy. T oxoplasma gondii was not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T . gondii . By concentrating oocysts in faecal pellets, snails may facilitate entry of T . gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates.

Environmental Microbiology↗
USGS2022

Forecasting and communicating the dispersion and fallout of ash during volcanic eruptions: lessons from the September 20, 2020 eruptive pulse at Sangay volcano, Ecuador

Volcanic ash is a hazard to human health and activities. Accurate and timely forecasts coupled with effective communication about the dispersion and fallout of volcanic ash during explosive events are essential to reduce impacts on local communities and limit economic losses. In this study, we present the first detailed description of an eruptive pulse at Sangay volcano and its eruption source parameters. The eruptive pulse on September 20, 2020, started at about 9:20 UTC and lasted between 90 and 100 min, producing an eruptive column that rapidly separated into (1) a higher (15.2 km above sea level, asl), gas-rich cloud moving east-southeast and (2) a lower (12.2 km asl), ash-rich cloud moving west and causing ash fallout up to 280 km from the volcano. Field data collected immediately after the event allow estimating the volume of bulk tephra to be between 1.5 and 5.0 × 10 6 m 3 , corresponding to a volcanic explosivity index of 2. The eruptive pulse, identified as violent Strombolian, emitted andesitic ash that was more mafic than products ejected by Sangay volcano in recent decades. Component analysis and glass chemistry of juvenile particles support the hypothesis that this event excavated deeper into the upper conduit compared to typical Strombolian activity at Sangay volcano, while grain-size analysis allows reconstruction of the total grain-size distribution of the fallout deposit. The discrepancies between the ash fallout simulations performed with the Ash3D online tool and the actual deposit are mainly the result of inaccurate pre- and syn-eruptive configurations and highlight the importance of additional processes such as aggregation. Communication products issued during the event included (1) several standard short reports, (2) volcano observatory notices for aviation, (3) social media posts, and (4) a special report providing the results of the ash fallout simulation. Although communication was effective with the authorities and the connected population, an effort must be made to reach the most vulnerable isolated communities for future events. This study shows that forecasting ash dispersion and fallout during volcanic eruptions can guide early warnings and trigger humanitarian actions, and should become a standard in volcano observatories worldwide.

Sangay volcano↗
USGS2008

Ground-water quality data in the middle Sacramento Valley study unit, 2006— Results from the California GAMA program

Ground-water quality in the approximately 3,340 mi 2 Middle Sacramento Valley study unit (MSACV) was investigated from June through September, 2006, as part of the California Groundwater Ambient Monitoring and Assessment (GAMA) program. The GAMA Priority Basin Assessment project was developed in response to the Groundwater Quality Monitoring Act of 2001 and is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Middle Sacramento Valley study was designed to provide a spatially unbiased assessment of raw ground-water quality within MSACV, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 108 wells in Butte, Colusa, Glenn, Sutter, Tehama, Yolo, and Yuba Counties. Seventy-one wells were selected using a randomized grid-based method to provide statistical representation of the study unit (grid wells), 15 wells were selected to evaluate changes in water chemistry along ground-water flow paths (flow-path wells), and 22 were shallow monitoring wells selected to assess the effects of rice agriculture, a major land use in the study unit, on ground-water chemistry (RICE wells). The ground-water samples were analyzed for a large number of synthetic organic constituents (volatile organic compounds [VOCs], gasoline oxygenates and degradates, pesticides and pesticide degradates, and pharmaceutical compounds), constituents of special interest (perchlorate, N-nitrosodimethylamine [NDMA], and 1,2,3-trichloropropane [1,2,3-TCP]), inorganic constituents (nutrients, major and minor ions, and trace elements), radioactive constituents, and microbial indicators. Naturally occurring isotopes (tritium, and carbon-14, and stable isotopes of hydrogen, oxygen, nitrogen, and carbon), and dissolved noble gases also were measured to help identify the sources and ages of the sampled ground water. Quality-control samples (blanks, replicates, laboratory matrix spikes) were collected at approximately 10 percent of the wells, and the results for these samples were used to evaluate the quality of the data for the ground-water samples. Field blanks rarely contained detectable concentrations of any constituent, suggesting that contamination was not a noticeable source of bias in the data for the ground-water samples. Differences between replicate samples were within acceptable ranges, indicating acceptably low variability. Matrix spike recoveries were within acceptable ranges for most constituents. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, water typically is treated, disinfected, or blended with other waters to maintain acceptable water quality. Regulatory thresholds apply to treated water that is served to the consumer, not to raw ground water. However, to provide some context for the results, concentrations of constituents measured in the raw ground water were compared with health-based thresholds established by the U.S. Environmental Protection Agency (USEPA) and California Department of Public Health (CDPH) and thresholds established for aesthetic concerns (secondary maximum contaminant levels, SMCL-CA) by CDPH. Comparisons between data collected for this study and drinking-water thresholds are for illustrative purposes only and are not indicative of compliance or noncompliance with regulatory thresholds. Most constituents that were detected in ground-water samples were found at concentrations below drinking-water thresholds. VOCs were detected in less than one-third and pesticides and pesticide degradates in just over one-half of the grid wells, and all detections of these constituents in samples from all wells of the MSACV study unit were below health-based thresholds. All detections of trace elements in samples from MSACV grid wells were below health-based thresholds, with the exceptions of arsenic and boron. Arsenic concentrations were above the USEPA maximum contaminant level (MCL-US) threshold in eight grid wells, and boron concentrations were above the CDPH notification level (NL-CA) in two grid wells. Arsenic was detected above the MCL-US in two flow-path wells. Arsenic, barium, boron, molybdenum, strontium, and vanadium were detected above health-based thresholds in a few of the RICE wells; these wells are not used to supply drinking water. All detections of radioactive constituents were below health-based thresholds, although six samples had activities of radon-222 above the lower proposed MCL-US threshold. Most of the samples from the MSACV wells had concentrations of major elements, total dissolved solids, and trace elements below the non-enforceable thresholds set for aesthetic concerns. Chloride and sulfate concentrations exceeded SMCL-CA thresholds in two and one grid well, respectively. Iron, manganese, and total dissolved solids concentrations were above the SMCL-CA thresholds in 1, 12, and 6 grid wells, respectively. Nitrate (nitrite plus nitrate, as dissolved nitrogen) concentrations from two grid wells were above the MCL-US threshold. There were no detections of microbial indicators in MSACV.

California↗
USGS1969

Hydrology of carbonate rock terranes — A review: With special reference to the United States

Limestone and other carbonate rocks are characterized by many unusual features and extreme conditions, either involving the hydrologic system within them or wrought by hydrologic conditions on them or through them. Perhaps there could be little agreement as to what is typical or average for the many features of carbonate rocks, as indicated by the following conditions: bare rock and thin soils are common, but so are thick soils; very highly permeable limestones are common, but so are poorly permeable ones; and rugged karst topographic features with underlying solution caverns are common, but so are flat, nearly featureless topographic conditions. Some conditions of carbonate terranes are suitable to man's needs and interests, such as the use of some permeable aquifers for water supply and the exploitation of caves for tourist attractions. On the other hand, many problems may exist, including: permeability too low for adequate water supply or so high that the aquifer retains too little water for use during periods of fair weather, soils too thin for growing of crops and for adequate filtration of wastes near the ground surface, instability of the ground for buildings and foundations in sinkhole areas, and unusually rugged topography. Some of the many variable conditions are readily observable, but others can be determined only by careful geologic and hydrologic studies. The need for knowing the specific geologic and hydrologic conditions at various places in limestone terranes, as well as the variations in hydrologic conditions with changing conditions and time, has resulted in many published reports on local areas and on special topical problems of limestone hydrology. Many of these reports have been used to advantage by the present writers in preparing this paper. The concept that secondary permeability is developed by circulation of water through openings with the accompanying enlargement of these openings by solution is now universally accepted in limestone terranes. Emphasis is placed on the hydrogeologic framework, or structural setting, in relation to the ease or difficulty of water to move from a source of recharge, through a part of the limestone, to a discharge area. Parts of the limestone favored by circulating ground water tend to develop solution openings, commonly in the upper part of the zone of saturation; as base level is lowered (sea level or perennial stream level), the related water table lowers in the limestone leaving air-filled caverns above the present zone of saturation in sinkhole areas. Reconstruction of the geologic and hydrologic history of a limestone area aids in determining the extent of development and the positions of fossil and present permeability. References are made to the hydrology of many limestone regions, especially those of the United States.

Journal of Hydrology↗
USGS1965

Hydrology of subsurface waste disposal, National Reactor Testing Station, Idaho: Annual progress report for 1964

The principal purpose of the past research program on geohydrology at the NRTS has been to acquire information on the physical and geochemical environment of the station. This requires a knowledge of the composition and structure of the earth materials underlying the plain, the inventory of the water resources, the dynamics of natural and man-produced changes in the hydrologic regimen, details of the hydrologic cycle, and relevant geochemical processes. The Geological Survey in the course of its early studies by Nace and others (IDO 22033-34-USGS) obtained, compiled, and analyzed a considerable amount of basic geologic and hydrologic information on these subjects. These basic goals were expanded and carried forward to guide the continuing research work. Jones (IDO 22042-USGS) emphasized the use of borehole geophysics and specialized down-hole techniques. Olmsted (IDO 22043-USGS) made a preliminary appraisal of the nature and distribution of the quality of ground water beneath the Station. Their work has been continued and elaborated upon by Morris and others (IDO 22044-USGS, 46-USGS) and the present report with greater emphasis on the regional geology and hydrology. This involved some procurement of needed information but, for the most part, involved a continued evaluation and refinement of data and results that had been acquired in the past. The Geological Survey also encouraged a more comprehensive study of the regional geologic structure including the use of aeromagnetic, gravity, and seismic geophysical techniques and cosponsored a seminar on it in 1964. Along with this investigation and study of the regional geology and of hydrologic principles operative in the basalt environment, and made possible because of it, research continues on the-hydrologic aspects of the disposal of low-level aqueous waste to the environment.

Idaho↗
USGS2014

Fluctuations in artesian pressure produced by passing railroad‐trains as shown in a well on Long Island, New York

Perhaps one of the chief interests of ground‐water hydrologists is the study of water‐level fluctuations. Since the beginning of the science of hydrology attempts have been made to interpret these phenomena and determine their significance. On the basis of actual observations and “with special reference to Long Island, New York,” Veatch [see 1 of “References” at end of paper] in 1906 considered in some detail several different causes of water‐level fluctuations. He placed the known causes under two general headings, natural and human. However, considering proximate rather than ultimate causes a further classification might be, and indeed often is, made with regard to the conditions under which the fluctuations are produced by a given agency, natural or human. Thus we speak of ”water‐table conditions“ and ”artesian conditions,“ realizing, however, that the distinction between the two is not always definite. The phenomena peculiar to artesian conditions are usually the result merely of the imperviousness of the confining beds relative to the particular aquifer under consideration. Indeed, it is recognized that perhaps even the most dense clay is not absolutely impervious to the flow of water, given a difference in head, sufficient to produce the flow, though it may be beyond the precision of the means now employed to detect the flow of water through such impervious strata.

New York↗
USGS2012

Advances in carbonate exploration and reservoir analysis

Carbonate reservoirs contain an increasingly important percentage of the world’s hydrocarbon reserves. This volume presents key recent advances in carbonate exploration and reservoir analysis. As well as a comprehensive overview of the trends in carbonate over the years, the volume focuses on four key areas: (1) emerging plays and techniques with special reference to lacustrine plays in syn-rift basins and development of super-giant heavy oil plays (2) improved reservoir characterization with examples from the Middle East and Europe and case studies of how outcrop analogues can provide key data for input to geological models (3) impact of fractures and faults in carbonates contributors highlight the need for integrated structural and diagenetic approaches in order to understand how fractures evolve as fluid-flow conduits (4) advances in geomodelling of carbonate reservoirs several papers discuss the application of new and innovative geomodelling and geostatistical techniques to carbonate reservoirs.

Book↗
USGS2011

Pre- and post-drill comparison of the Mount Elbert gas hydrate prospect, Alaska North Slope

In 2006, the United States Geological Survey (USGS) completed a detailed analysis and interpretation of available 2-D and 3-D seismic data, along with seismic modeling and correlation with specially processed downhole well log data for identifying potential gas hydrate accumulations on the North Slope of Alaska. A methodology was developed for identifying sub-permafrost gas hydrate prospects within the gas hydrate stability zone in the Milne Point area. The study revealed a total of 14 gas hydrate prospects in this area. In order to validate the gas hydrate prospecting protocol of the USGS and to acquire critical reservoir data needed to develop a longer-term production testing program, a stratigraphic test well was drilled at the Mount Elbert prospect in the Milne Point area in early 2007. The drilling confirmed the presence of two prominent gas-hydrate-bearing units in the Mount Elbert prospect, and high quality well logs and core data were acquired. The post-drill results indicate pre-drill predictions of the reservoir thickness and the gas-hydrate saturations based on seismic and existing well data were 90% accurate for the upper unit (hydrate unit D) and 70% accurate for the lower unit (hydrate unit C), confirming the validity of the USGS approach to gas hydrate prospecting. The Mount Elbert prospect is the first gas hydrate accumulation on the North Slope of Alaska identified primarily on the basis of seismic attribute analysis and specially processed downhole log data. Post-drill well log data enabled a better constraint of the elastic model and the development of an improved approach to the gas hydrate prospecting using seismic attributes.

Alaska↗
USGS2017

Volcanic unrest and hazard communication in Long Valley Volcanic Region, California

The onset of volcanic unrest in Long Valley Caldera, California, in 1980 and the subsequent fluctuations in unrest levels through May 2016 illustrate: (1) the evolving relations between scientists monitoring the unrest and studying the underlying tectonic/magmatic processes and their implications for geologic hazards, and (2) the challenges in communicating the significance of the hazards to the public and civil authorities in a mountain resort setting. Circumstances special to this case include (1) the sensitivity of an isolated resort area to media hype of potential high-impact volcanic and earthquake hazards and its impact on potential recreational visitors and the local economy, (2) a small permanent population (~8000), which facilitates face-to-face communication between scientists monitoring the hazard, civil authorities, and the public, and (3) the relatively frequent turnover of people in positions of civil authority, which requires a continuing education effort on the nature of caldera unrest and related hazards. Because of delays associated with communication protocols between the State and Federal governments during the onset of unrest, local civil authorities and the public first learned that the U.S. Geological Survey was about to release a notice of potential volcanic hazards associated with earthquake activity and 25-cm uplift of the resurgent dome in the center of the caldera through an article in the Los Angeles Times published in May 1982. The immediate reaction was outrage and denial. Gradual acceptance that the hazard was real required over a decade of frequent meetings between scientists and civil authorities together with public presentations underscored by frequently felt earthquakes and the onset of magmatic CO 2 emissions in 1990 following a 11-month long earthquake swarm beneath Mammoth Mountain on the southwest rim of the caldera. Four fatalities, one on 24 May 1998 and three on 6 April 2006, underscored the hazard posed by the CO 2 emissions. Initial response plans developed by county and state agencies in response to the volcanic unrest began with “The Mono County Volcano Contingency Plan” and “Plan Caldera” by the California Office of Emergency Services in 1982–84. They subsequently became integrated in the regularly updated County Emergency Operation Plan. The alert level system employed by the USGS also evolved from the three-level “Notice-Watch-Warning” system of the early 1980s through a five level color-code to the current “Normal-Advisory-Watch-Warning” ground-based system in conjunction with the international 4-level aviation color-code for volcanic ash hazards. Field trips led by the scientists proved to be a particularly effective means of acquainting local residents and officials with the geologically active environment in which they reside. Relative caldera quiescence from 2000 through 2011 required continued efforts to remind an evolving population that the hazards posed by the 1980–2000 unrest persisted. Renewed uplift of the resurgent dome from 2011 to 2014 was accompanied by an increase in low-level earthquake activity in the caldera and beneath Mammoth Mountain and continues through May 2016. As unrest levels continue to wax and wane, so will the communication challenges.

Book chapter↗
USGS2008

Chronic toxicity of hydrogen peroxide to Daphnia magna in a continuous exposure, flow-through test system

A flow-through, continuous exposure test system was developed to expose Daphnia magna to an unstable compound. 35% Perox-Aid?? is a specially formulated hydrogen peroxide (a highly oxidative chemical) product approved for use in U.S. aquaculture and therefore has the potential to be released from aquaculture facilities and pose a risk to aquatic invertebrates. The study objective was to assess the effects of 35% Perox-Aid?? on an aquatic invertebrate by evaluating the survival, growth, production, and gender ratio of progeny from a representative aquatic invertebrate continuously exposed to 35% Perox-Aid??. The study design consisted of 6 treatment groups (10 test chambers each) with target hydrogen peroxide concentrations of 0.0, 0.32, 0.63, 1.25, 2.5, and 5.0??mg L- 1. The study was initiated with < 24-h-old Daphnia (1 daphnid per chamber) that were exposed to hydrogen peroxide for 21??days. Hydrogen peroxide concentrations ??? 1.25??mg L- 1 had no significant effect on Daphnia time to death compared to controls and no significant effect on the time to first brood production and the number of broods produced. Concentrations ??? 0.63??mg L- 1 had no significant effect on the total number of young produced. Concentrations ??? 0.32??mg L- 1 had a negative effect on Daphnia growth. Hydrogen peroxide had no significant effect on the gender ratio of young produced. All second generation Daphnia were female. A continuous discharge of hydrogen peroxide into aquatic ecosystems is not likely to affect cladocerans if the concentration is maintained at ??? 0.63??mg L- 1 for less than 21??days.

Science of the Total Environment↗
USGS2007

Use of eyeballs for establishing ploidy of Asian carp

Grass carp Ctenopharyngodon idella, silver carp Hypophthalmichthys molitrix, and bighead carp H. nobilis are now established and relatively common in the Mississippi and Atchafalaya rivers. Commercial fishers of Louisiana's large rivers report recurrent catches of grass carp, and the frequency of bighead carp and silver carp catch is increasing. Twelve black carp Mylopharyngodon piceus were recently captured from the Mississippi and Atchafalaya River system, and 10 were analyzed for ploidy. By using the methods described herein, all 10 fish were determined to be diploid. Such correct identifications of ploidy of feral Asian carp species, as well as other species, would provide science-based information constructive for meeting reporting requirements, tracking fish movements, and forecasting expansion of species distribution. To investigate the postmortem period for sample collection and to lessen demands on field operations for obtaining samples, a laboratory study was performed to determine the length of time for which eyeballs from postmortem black carp could be used for ploidy determinations. Acquiring eyes rather than blood is simpler and quicker and requires no special supplies. An internal DNA reference standard with a documented genome size, including erythrocytes from diploid black carp or Nile tilapia Oreochromis niloticus, was analyzed simultaneously with cells from seven known triploid black carp to assess ploidy through 12 d after extraction. Ploidy determinations were reliable through 8 d postmortem. The field process entails excision of an eyeball, storage in a physiological buffer, and shipment within 8 d at refrigeration temperatures (4??C) to the laboratory for analysis by flow cytometry. ?? Copyright by the American Fisheries Society 2007.

North American Journal of Fisheries Management↗
USGS1987

Methods for geochemical analysis

The laboratories for analytical chemistry within the Geologic Division of the U.S. Geological Survey are administered by the Office of Mineral Resources. The laboratory analysts provide analytical support to those programs of the Geologic Division that require chemical information and conduct basic research in analytical and geochemical areas vital to the furtherance of Division program goals. Laboratories for research and geochemical analysis are maintained at the three major centers in Reston, Virginia, Denver, Colorado, and Menlo Park, California. The Division has an expertise in a broad spectrum of analytical techniques, and the analytical research is designed to advance the state of the art of existing techniques and to develop new methods of analysis in response to special problems in geochemical analysis. The geochemical research and analytical results are applied to the solution of fundamental geochemical problems relating to the origin of mineral deposits and fossil fuels, as well as to studies relating to the distribution of elements in varied geologic systems, the mechanisms by which they are transported, and their impact on the environment.

Bulletin↗
USGS2007

Survey of chemical contaminants in the Hanalei River, Kaua'i, Hawai'i, 2001

The Hanalei River on the island of Kaua'i in Hawai'i was designated an American Heritage River in 1998, providing special attention to natural resource protection, economic revitalization, and historic and cultural preservation. Agricultural, urban, and tourism-related activities are potential sources of contamination within the Hanalei River watershed. The objective of this study was to measure certain persistent organic chemicals and elements in the Hanalei River. During a relatively low-flow period in December of 2001, samples of native Akupa sleeper fish ( Eleotris sandwicensis ), freshwater Asian clam ( Corbicula fluminea ), giant mud crab ( Scylla serrata ), surface water, and stream bed sediment were collected from a lower estuarine reach of the river near its mouth at Hanalei Bay and from an upper reach at the Hanalei National Wildlife Refuge. Samples were analyzed for residues of urban and agricultural chemicals including organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and elements (including mercury, lead, cadmium, arsenic, and selenium). Organic contaminants were extracted from the samples with solvent, enriched, and then analyzed by gas chromatographic analysis with electron capture or mass spectrometric detection. Samples were acid-digested for semi-quantitative analysis for elements by inductively-coupled plasma-mass spectrometry and for quantitative analysis by atomic absorption spectrophotometry. Concentrations of organochlorine pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in biota, surface water, and bed sediment sampled from the Hanalei River ranged from nondetectable to very low levels. Polychlorinated biphenyls were below detection in all samples. Dieldrin, the only compound detected in the water samples, was present at very low concentrations of 1-2 nanograms per liter. Akupa sleeper fish and giant mud crabs from the lower reach ranged from 1 to 5 nanograms per gram (wet weight) dieldrin and from less than 0.3 to 2.1 nanograms per gram total chlordane. Concentrations of individual polycyclic aromatic hydrocarbons in the lower reach bed sediments ranged from less than 1 to 190 nanograms per gram (dry weight). Relative concentrations (patterns) of the polycyclic aromatic hydrocarbons in one portion of a sediment sample indicated combustion sources. Concentrations of elements in the surface water, biota, and sediment samples were below toxicity thresholds of ecological concern. In summary, concentrations of the organic contaminants and elements targeted by this study of the Hanalei River in 2001 were below U.S. Environmental Protection Agency probable adverse effects levels for aquatic organisms.

Scientific Investigations Report↗
USGS1990

Statistical inference for capture-recapture experiments

This monograph presents a detailed, practical exposition on the design, analysis, and interpretation of capture-recapture studies. The Lincoln-Petersen model (Chapter 2) and the closed population models (Chapter 3) are presented only briefly because these models have been covered in detail elsewhere. The Jolly- Seber open population model, which is central to the monograph, is covered in detail in Chapter 4. In Chapter 5 we consider the "enumeration" or "calendar of captures" approach, which is widely used by mammalogists and other vertebrate ecologists. We strongly recommend that it be abandoned in favor of analyses based on the Jolly-Seber model. We consider 2 restricted versions of the Jolly-Seber model. We believe the first of these, which allows losses (mortality or emigration) but not additions (births or immigration), is likely to be useful in practice. Another series of restrictive models requires the assumptions of a constant survival rate or a constant survival rate and a constant capture rate for the duration of the study. Detailed examples are given that illustrate the usefulness of these restrictions. There often can be a substantial gain in precision over Jolly-Seber estimates. In Chapter 5 we also consider 2 generalizations of the Jolly-Seber model. The temporary trap response model allows newly marked animals to have different survival and capture rates for 1 period. The other generalization is the cohort Jolly-Seber model. Ideally all animals would be marked as young, and age effects considered by using the Jolly-Seber model on each cohort separately. In Chapter 6 we present a detailed description of an age-dependent Jolly-Seber model, which can be used when 2 or more identifiable age classes are marked. In Chapter 7 we present a detailed description of the "robust" design. Under this design each primary period contains several secondary sampling periods. We propose an estimation procedure based on closed and open population models that allows for heterogeneity and trap response of capture rates (hence the name robust design). We begin by considering just 1 age class and then extend to 2 age classes. When there are 2 age classes it is possible to distinguish immigrants and births. In Chapter 8 we give a detailed discussion of the design of capture-recapture studies. First, capture-recapture is compared to other possible sampling procedures. Next, the design of capture-recapture studies to minimize assumption violations is considered. Finally, we consider the precision of parameter estimates and present figures on proportional standard errors for a variety of initial parameter values to aid the biologist about to plan a study. A new program, JOLLY, has been written to accompany the material on the Jolly-Seber model (Chapter 4) and its extensions (Chapter 5). Another new program, JOLLYAGE, has been written for a special case of the age-dependent model (Chapter 6) where there are only 2 age classes. In Chapter 9 a brief description of the different versions of the 2 programs is given. Chapter 10 gives a brief description of some alternative approaches that were not considered in this monograph. We believe that an excellent overall view of capture- recapture models may be obtained by reading the monograph by White et al. (1982) emphasizing closed models and then reading this monograph where we concentrate on open models. The important recent monograph by Burnham et al. (1987) could then be read if there were interest in the comparison of different populations.

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