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At least 343 records · Page 19Linked to original sources
USGS2005

Occurrence of fecal-indicator bacteria and protocols for identification of fecal-contamination sources in selected reaches of the West Branch Brandywine Creek, Chester County, Pennsylvania

The presence of fecal-indicator bacteria indicates the potential presence of pathogens originating from the fecal matter of warm-blooded animals. These pathogens are responsible for numerous human diseases ranging from common diarrhea to meningitis and polio. The detection of fecal-indicator bacteria and interpretation of the resultant data are, therefore, of great importance to water-resource managers. Current (2005) techniques used to assess fecal contamination within the fluvial environment primarily assess samples collected from the water column, either as grab samples or as depth- and (or) width-integrated samples. However, current research indicates approximately 99 percent of all bacteria within nature exist as attached, or sessile, bacteria. Because of this condition, most current techniques for the detection of fecal contamination, which utilize bacteria, assess only about 1 percent of the total bacteria within the fluvial system and are, therefore, problematic. Evaluation of the environmental factors affecting the occurrence and distribution of bacteria within the fluvial system, as well as the evaluation and modification of alternative approaches that effectively quantify the larger population of sessile bacteria within fluvial sediments, will present water-resource managers with more effective tools to assess, prevent, and (or) eliminate sources of fecal contamination within pristine and impaired watersheds. Two stream reaches on the West Branch Brandywine Creek in the Coatesville, Pa., region were studied between September 2002 and August 2003. The effects of sediment particle size, climatic conditions, aquatic growth, environmental chemistry, impervious surfaces, sediment and soil filtration, and dams on observed bacteria concentrations were evaluated. Alternative approaches were assessed to better detect geographic sources of fecal contamination including the use of turbidity as a surrogate for bacteria, the modification and implementation of sandbag bacteria samplers, and the use of optical brighteners. For the purposes of this report, sources of bacteria were defined as geographic locations where elevated concentrations of bacteria are observed within, or expected to enter, the main branch of the West Branch Brandywine Creek. Biologic sources (for example, waterfowl) were noted where applicable; however, no specific study of biologic sources (such as bacterial source tracking) was conducted. Data indicated that specific bacterial populations within fluvial sediments could be related to specific particle-size ranges. This relation is likely the result of the reduced porosity and permeability associated with finer sediments and the ability of specific bacteria to tolerate particular environments. Escherichia coli (E. coli) showed a higher median concentration (2,160 colonies per gram of saturated sediment) in the 0.125 to 0.5-millimeter size range of natural sediments than in other ranges, and enterococcus bacteria showed a higher median concentration (61,830 colonies per gram of saturated sediment) in the 0.062 to 0.25-millimeter size range of natural sediments than in other ranges. There were insufficient data to assess the particle-size relation to fecal coliform bacteria and (or) fecal streptococcus bacteria. Climatic conditions were shown to affect bacteria concentrations in both the water column and fluvial sediments. Drought conditions in 2002 resulted in lower overall bacteria concentrations than the more typically wet year of 2003. E. coli concentrations in fluvial sediment along the Coatesville study reach in 2002 had a median concentration of 92 colonies per gram of saturated sediment; in 2003, the median concentration had risen to 4,752 colonies per gram of saturated sediment. Symbiotic relations between bacteria and aquatic growth were likely responsible for increased bacteria concentrations observed within an impoundment area on the Coatesville study reach. This reach showed evidence of elevated aquatic growth and sharp increases in E. coli concentrations from upstream to downstream through the impoundment area in both 2002 and 2003. In 2003, E. coli concentrations within the waters column increased from 940 colonies per 100 milliliters upstream to 6,000 colonies per 100 milliliters at the dam crest. Given that these bacteria likely resulted from natural bacterial regrowth, the use of E. coli as an indicator of fecal contamination was severely impaired. Variable environmental conditions along the West Branch Brandywine Creek made the common field-chemical parameters of specific conductance, temperature, pH, and dissolved oxygen ineffective and (or) impossible to use for the determination of inputs of fecal contamination. Extreme variations in chemical gradients commonly were related to the urban/industrial signature of the watershed. For example, during base-flow sampling in 2002, specific-conductance values exceeding 1,000 microsiemens per centimeter observed in effluent from a local steel mill. This effluent raised the specific conductance within the West Branch Brandywine from just above 200 microsiemens per centimeter upstream from the outfall to just below 500 microsiemens per centimeter downstream from the outfall. These chemical gradients also, likely, had an effect on the initial colonization of bacteria, the formation of biofilms, and the persistence of certain types of bacteria along the study reach. Data collected in 2003 indicated that nutrients increased during both base-flow and stormflow conditions along the Coatesville study reach. For example, during base-flow sampling in 2003, 20 pounds of phosphorus was shown to enter the West Branch Brandywine Creek along the Coatesville study reach. The largest contributors to this base-flow nutrient load were likely two wastewater-treatment facilities adjacent to the study reach. During stormflow sampling in 2003, 480 pounds of phosphorus was shown to enter the West Branch Brandywine Creek along the Coatesville study reach. Data, along with other research, indicated the largest contributor to this stormflow nutrient load was likely remobilized sediment originating from a large dam impoundment. These elevated nutrient concentrations were considered sufficient to promote accelerated aquatic growth along the reach. Data collected in 2003 showed that wastewater constituents entered the West Branch Brandywine Creek largely from urban storm-sewer systems. Samples from the primary storm sewer for the city of Coatesville had detections for 20 of 69 wastewater constituents. These constituents included both strong and weak indicators of fecal contamination and generally indicated the storm-sewer system along the Coatesville study reach was a likely source of fecal-indicator bacteria and fecal contamination under base-flow conditions. By comparison, 5 constituents were detected in samples from the upstream end of the reach, and 10 constituents were detected in samples from the downstream end of the reach. During stormflow, numbers of detections were similar along the entire length of the study reach-five in samples from the upstream end, eight in samples from the center of the reach, and seven in samples from the downstream end of the reach. These data indicate that point sources (such as culverts and pipes, septic systems, and wastewater-treatment facilities) are not likely the origin of bacteria contamination during stormflow. The bacteria concentrations observed during stormflow events probably result from remobilized sessile bacteria stored within fluvial sediments. In this case, these bacteria should not be considered indicators of current fecal contamination. Impervious surfaces were found to increase bacteria concentrations along the West Branch Brandywine Creek because contaminated runoff from impervious areas generally flows into, and is concentrated within, the confines of the local storm-sewer system. During 2002, storm-sewer outfalls draining impervious areas were associated with all major locations of elevated bacterial concentrations (greater than 1,200 colonies per gram of saturated sediment) in fluvial sediments. During 2003, wetter conditions and overall bacteria concentrations higher than in 2002 resulted in point sources of bacterial contamination becoming less pronounced; however, the storm-sewer system, draining adjacent impervious areas, was still observed to be the primary source of bacteria along the reach. Where stormwater and (or) other runoff from these areas was allowed to infiltrate and (or) flow through wetland and riparian buffers, bacteria concentrations were not observed to be elevated above background levels commonly observed throughout similar areas of the same reach. Two run-of-the-river dams along the Coatesville study reach were evaluated for their effects on observed bacterial concentrations. These dams were shown to have greater or lesser effects on bacterial concentrations depending on the size of the structure and the capacity of the structure to impede flows. The smaller upstream dam had an approximate height of 3 feet and showed little observed effect on measured turbidity values; these data indicated that the dam did not effectively impede the flow of water or sediment within the West Branch Brandywine Creek. Consequently, this small dam did not show any observed effect on bacterial concentrations either upstream or downstream of the structure. The larger dam, near the middle of the reach, had an approximate height of 20 feet and showed greater effects on both turbidity and bacteria concentrations. The capacity of the larger dam to impede flows, combined with nutrients entering the reach, resulted in increased biologic activity throughout the impoundment area. Within this larger impoundment, enterococcus bacteria populations were observed to decrease sharply and E. coli bacteria populations were observed to increase sharply as flow approached the dam crest. All bacteria levels were then observed to drop to background levels, in both the water column and fluvial sediment, immediately downstream from the dam crest. Additional study is required to determine the cause for this rapid die off. Turbidity was assessed as a potential surrogate for E. coli bacteria. Regression analysis indicated higher turbidity levels usually can indicate higher concentrations of bacteria (R2 = 0.67), but the relation was too sporadic on the West Branch Brandywine Creek to use turbidity as a surrogate for estimated bacteria concentrations. Evaluation of data from individual base-flow and stormflow events resulted in variable and generally poor statistical relations between E. coli bacteria and turbidity (R2 values ranged from 0.02 to 0.94). Sandbag samplers were used in 2003 to determine their suitability for the assessment of fecal contamination. Sandbag samplers rely on the ability of bacteria to attach to surfaces and use the larger sessile bacteria populations instead of the more commonly used planktonic bacteria populations. E. coli bacteria concentrations observed in the sandbag samplers, after 1 week in place, were similar to those found within natural sediments collected concurrently. Enterococcus bacteria concentrations within the same sandbag samplers were not similar, and were generally lower, than those observed within the natural sediments. This discrepancy was likely because sand within the samplers was sieved to a size that was likely too coarse for enterococcus bacteria to persist. Optical-brightener samplers were installed along with each sandbag sampler. Optical brighteners are additives used in common household detergents; therefore, detection of optical brighteners, along with elevated fecal-indicator bacteria concentrations, strongly indicates a link to humans. Positive results for optical brighteners were detected only at the outfalls of two sewage-treatment facilities; because of treatment of the effluent from these facilities, these samples did not have elevated bacteria concentrations. The lack of additional positive results was largely because this method is not sensitive to low concentrations of optical brighteners.

Pennsylvania↗
USGS1996

Age dating of shallow groundwater with chlorofluorocarbons, tritium/helium: 3, and flow path analysis, southern New Jersey coastal plain

Groundwater age dating through the combination of transient tracer methods (chlorofluorocarbons (CFCs) and tritium/helium 3 ( 3 H/ 3 He)) and groundwater flow path analysis is useful for investigating groundwater travel times, flow patterns, and recharge rates, as demonstrated by this study of the homogeneous shallow, unconfined Kirkwood-Cohansey aquifer system in the southern New Jersey coastal plain. Water samples for age dating were collected from three sets of nested observation wells (10 wells) with 1.5-m-long screens located near groundwater divides. Three steady state finite difference groundwater flow models were calibrated by adjusting horizontal and vertical hydraulic conductivities to match measured heads and head differences (range, 0.002–0.23 m) among the nested wells, with a uniform recharge rate of 0.46 m per year and porosities of 0.35 (sand) and 0.45 (silt) that were assumed constant for all model simulations and travel time calculations. The simulated groundwater travel times increase with depth in the aquifer, ranging from about 1.5 to 6.5 years for the shallow wells (screen bottoms 3–4 m below the water table), from about 10 to 25 years for the medium-depth wells (screen bottoms 8–19 m below the water table), and from about 30 to more than 40 years for the deep wells (screen bottoms 24–26 m below the water table). Apparent groundwater ages based on CFC- and 3 H/ 3 He-dating techniques and model-based travel times could not be statistically differentiated, and all were strongly correlated with depth. Confinement of 3He was high because of the rapid vertical flow velocity (of the order of 1 m/yr), resulting in clear delineation of groundwater travel times based on the 3 H/ 3 He-dating technique. The correspondence between the 3 H/ 3 He and CFC ages indicates that dispersion has had a minimal effect on the tracer-based ages of water in this aquifer. Differences between the tracer-based apparent ages for seven of the 10 samples were smaller than the error values. A slight bias toward older apparent ages, found not to be statistically significant, was noted for the 3 H/ 3 He-dating technique relative to the CFC-dating technique. This result may be caused by enrichment of local air in CFC-Il and CFC-12 from urban and industrial sources in the northeastern United States and minor contamination from sampling equipment. The demonstrated validity of the combined tracer-dating techniques to determine the age of water in the Kirkwood-Cohansey aquifer system indicates that groundwater flow models can be refined when apparent ages based on 3 H/ 3 He- and CFC- dating are used as calibration targets.

New Jersey↗
USGS2007

Overview of developmental, reproductive, and behavioral/ neurological effects of mercury exposures in wildlife

We review wildlife/mercury literature and our own research findings that demonstrate the relevance of wildlife toxicity data in protecting human health. Methylmercury affects wildlife through reduced adult survival and reproduction, aberrant behavior, immune system effects, and teratogenic effects. Methylmercury can readily cross the blood-brain barrier, is excreted into eggs in birds, and is transferred to young mammals across the placenta and in milk. Its principal effect on wildlife is on neurological functions. Wild mink (Mustela vison) and otter (Lutra canadensis) have died from methylmercury poisoning, with signs of poisoning including anorexia, loss of weight, incoordination, tremors, and convulsions, which are symptoms similar to those experienced by mercury-poisoned humans. Mammals also may experience tonic and clonic convulsions and an increase in fetal anomalies, again paralleling toxic problems in people. Antibody-producing cells can be suppressed by methylmercury. Microscopically, the most notable lesions are in the cerebrum. Extensive vacuolation of hepatocytes in the liver and necrosis and other changes in the appearance of the proximal convoluted tubules of the kidneys are often noted. When harp seals (Pagophilus groenlandicus) were dosed with methylmercury chloride the number of circulating erythrocytes decreased and white blood cell counts greatly increased. The poisoned seals also suffered from uremia, hyperproteinemia, hypercholesterolemia, hyperbilirubinemia, and elevations in lactic dehydrogenase and alkaline phosphatase. In birds, signs of methylmercury poisoning included emaciation and weakness in the extremities, which progressed until the birds died. Mercury poisoning in birds and mammals can be diagnosed from a combination of the signs of poisoning if the animal is still alive, the pathological effects seen in a gross necropsy, the histopathological effects seen with a microscope, and the concentrations of mercury in various tissues. Our studies with mallards (Anas platyrhynchos) suggest that the dietary concentrations of mercury that cause toxicity are lower than those set in fish consumption advisories to protect humans. Because wild mammals and birds are so sensitive to methylmercury poisoning and cannot escape dietary exposure the way humans can, guidelines set to protect wild birds and mammals may very well provide a margin of safety for human health.

Book chapter↗
USGS2021

Iñupiaq knowledge of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska

Successful wildlife management depends upon coordination and consultation with local communities. However, much of the research used to inform management is often derived solely from data collected directly from wildlife. Indigenous people living in the Arctic have a close connection to their environment, which provides unique opportunities to observe their environment and the ecology of Arctic species. Further, most northern Arctic communities occur within the range of polar bears ( nanuq , Ursus maritimus ) and have experienced significant climatic changes. Here, we used semi-structured interviews from 2017 to 2019 to document Iñupiaq knowledge of polar bears observed over four decades in four Alaskan communities in the range of the Southern Beaufort Sea polar bear subpopulation: Wainwright, Utqiaġvik, Nuiqsut, and Kaktovik. All but one of 47 participants described directional and notable changes in sea ice, including earlier ice breakup, later ice return, thinner ice, and less multiyear pack ice. These changes corresponded with observations of bears spending more time on land during the late summer and early fall in recent decades—observations consistent with scientific and Indigenous knowledge studies in Alaska, Canada, and Greenland. Participants noted that polar bear and seal body condition and local abundance either varied geographically or exhibited no patterns. However, participants described a recent phenomenon of bears being exhausted and lethargic when arriving on shore in the summer and fall after extensive swims from the pack ice. Further, several participants suggested that maternal denning is occurring more often on land than sea ice. Participants indicated that village and regional governments are increasingly challenged to obtain resources needed to keep their communities safe as polar bears spend more time on land, an issue that is likely to be exacerbated both in this region and elsewhere as sea ice loss continues.

Alaska↗
USGS2009

A review of plague persistence with special emphasis on fleas

Sylvatic plague is highly prevalent during infrequent epizootics that ravage the landscape of western North America. During these periods, plague dissemination is very efficient. Epizootics end when rodent and flea populations are decimated and vectored transmission declines. A second phase (enzootic plague) ensues when plague is difficult to detect from fleas, hosts or the environment, and presents less of a threat to public health. Recently, researchers have hypothesized that the bacterium (Yersinia pestis) responsible for plague maintains a continuous state of high virulence and thus only changes in transmission efficiency explain the shift between alternating enzootic and epizootic phases. However, if virulent transmission becomes too inefficient, strong selection might favor an alternate survival strategy. Another plausible non-exclusive hypothesis, best supported from Asian field studies, is that Y. pestis persists (locally) at foci by maintaining a more benign relationship within adapted rodents during the long expanses of time between outbreaks. From this vantage, it can revert to the epizootic (transmission efficient) form. Similarly, in the United States (US), enzootic plague persistence has been proposed to develop sequestered within New World rodent carriers. However, the absence of clear support for rodent carriers in North America has encouraged a broader search for alternative explanations. A telluric plague existence has been proposed. However, the availability of flea life stages and their hosts could critically supplement environmental plague sources, or fleas might directly represent a lowlevel plague reservoir. Here, we note a potentially pivotal role for fleas. These epizootic plague vectors should be closely studied with newer more exacting methods to determine their potential to serve as participants in or accomplices to a plague persistence reservoir.

Journal of Vector Borne Diseases↗
USGS2026

Lower Eastern Shore Tributary summary: A summary of trends in tidal water quality and associated factors, 1985-2023

The Lower Eastern Shore Tributary Summary outlines change over time according to a suite of monitored tidal water quality parameters and associated potential drivers of those trends for the period 1985 – 2023, and provides a brief description of the current state of knowledge explaining these observed changes. Water quality parameters described include surface (above pycnocline) total nitrogen (TN), surface total phosphorus (TP), surface water temperature (WTEMP), spring (March-May) and summer (July-September) surface chlorophyll a, summer bottom (below pycnocline) dissolved oxygen (DO) concentrations, and Secchi disk depth (a measure of water clarity). Results for annual bottom TP, bottom TN, surface ortho-phosphate (PO4), surface dissolved inorganic nitrogen (DIN), surface total suspended solids (TSS), and summer surface DO concentrations are provided in an Appendix B. Drivers discussed include physiographic watershed characteristics, changes in TN, TP, and sediment loads from the watershed to tidal waters, expected effects of changing land use, and implementation of nutrient management and natural resource conservation practices. Factors internal to estuarine waters that also play a role as drivers are described including biogeochemical processes, physical forces such as winddriven mixing of the water column and increase in rainfall intensity and volume, and biological factors such as phytoplankton biomass and the presence of submersed aquatic vegetation. Continuing to track water quality response and investigating these influencing factors are important steps to understanding water quality patterns and changes in the Lower Eastern Shore. The intended audiences for this report include, but are not limited to, 1) technical managers within jurisdictions who use tidal water quality to inform management decisions, 2) local watershed organizations that are trying to understand these analyses and working to connect them to their local area(s), and 3) federal, state, and academic researchers. Figure 1 presents a conceptual model highlighting these intended audiences. The Tributary Summary documents are sources of readily available background for change over time in tidal water quality observed with monitoring data. They help answer questions related to water quality, show how landscape factors drive water-quality changes over time, provide support for management decisions that may alter water quality trends and living resources conditions, and highlight where there may be information or knowledge gaps.

Maryland, Virginia↗
USGS2008

Age, distribution, and stratigraphic relationship of rock units in the San Joaquin Basin Province, California: Chapter 5 in Petroleum systems and geologic assessment of oil and gas in the San Joaquin Basin Province, California

The San Joaquin Basin is a major petroleum province that forms the southern half of California’s Great Valley, a 700-km-long, asymmetrical basin that originated between a subduction zone to the west and the Sierra Nevada to the east. Sedimentary fill and tectonic structures of the San Joaquin Basin record the Mesozoic through Cenozoic geologic history of North America’s western margin. More than 25,000 feet (>7,500 meters) of sedimentary rocks overlie the basement surface and provide a nearly continuous record of sedimentation over the past ~100 m.y. Further, depositional geometries and fault structures document the tectonic evolution of the region from forearc setting to strike-slip basin to transpressional margin. Sedimentary architecture in the San Joaquin Basin is complicated because of these tectonic regimes and because of lateral changes in depositional environment and temporal changes in relative sea level. Few formations are widespread across the basin. Consequently, a careful analysis of sedimentary facies is required to unravel the basin’s depositional history on a regional scale. At least three high-quality organic source rocks formed in the San Joaquin Basin during periods of sea level transgression and anoxia. Generated on the basin’s west side, hydrocarbons migrated into nearly every facies type in the basin, from shelf and submarine fan sands to diatomite and shale to nonmarine coarse-grained rocks to schist. In 2003, the U.S. Geological Survey (USGS) completed a geologic assessment of undiscovered oil and gas resources and future additions to reserves in the San Joaquin Valley of California (USGS San Joaquin Basin Province Assessment Team, this volume, chapter 1). Several research aims supported this assessment: identifying and mapping the petroleum systems, modeling the generation, migration, and accumulation of hydrocarbons, and defining the volumes of rock to be analyzed for additional resources. To better understand the three dimensional relationships between hydrocarbon source and reservoir rocks, we compiled a database consisting of more than 13,000 well picks and of one-mile resolution seismic grids. Both the well picks and the seismic grids characterize the depths to the top of key stratigraphic units. This database formed the basis of subsequent numerical modeling efforts, including the construction of a three- dimensional geologic model (Hosford Scheirer, this volume, chapter 7) and simulation of the petroleum systems in space and time (Peters, Magoon, Lampe, and others, this volume, chapter 12). To accomplish this modeling, we synthesized the age, geographic distribution, lithology, and petroleum characteristics of hydrocarbon source and reservoir rocks in the basin. The results of that synthesis are presented in this paper in the form of new stratigraphic correlation columns for the northern, central, and southern San Joaquin Valley (fig. 5.1; note that all figures are at the back of this report, following the References Cited). The stratigraphic relationships and ages published here draw heavily on published and unpublished studies of the San Joaquin Basin. The stratigraphy presented in each of the columns necessarily idealizes the subsurface geology over a relatively large area, instead of representing the specific geology at an individual well, oil and gas field, or outcrop. In this paper we present the background rationale for defining the geographic divisions of the basin (inset map, fig. 5.1), the paleontological time scales used for assigning absolute ages to rock units (figs. 5.2 and 5.3), and the supporting maps illustrating the geographic distribution of each rock type included in the stratigraphic column (figs. 5.4 through 5.64).

California↗
USGS2026

Small-volume tephra deposits of the May 1924 explosions from Halemaʻumaʻu, Kīlauea volcano, and their origin

More than 50 explosive eruptions occurred from Halemaʻumaʻu at Kīlauea volcano over 17 days from May 11 to 27, 1924. Ballistics weighing as much as 14,000 kg were ejected and most landed within 2 km of the vent. Fine ash made up a major component of the tephra and was dispersed tens of kilometers downwind. Draining of the Halemaʻumaʻu lava lake occurred in late February 1924, with the crater floor eventually subsiding by a further ∼70 m (to ∼180 m below the crater rim) by the time the first explosions took place during the night of May 10–11. The largest explosions occurred on May 17–18 and smaller explosions continued until May 27, at which point Halemaʻumaʻu had more than doubled in width and depth. The explosions generated plumes reaching up to ∼10 km high with ballistics ejected up to 2 km from the crater. Almost 100 years later, we investigate and characterize the preserved tephra deposits within ∼3 km of the 1924 crater rim. Grain size and shape analyses were performed on 202 samples collected from 34 tephra profiles using dynamic image analysis, with a subset of layers from nine tephra profiles used for componentry (200 grains per layer in the 0.5–1 mm size fraction). Additionally, we characterize the average diameters (using the five largest clasts) at 216 locations and measure the average diameters of 2291 ballistics (largest per ∼100 m 2 area). Physical descriptions from fieldwork and grain size distributions were used to subdivide the tephra layers into five lithofacies: coarse homogeneous, fine homogenous, red ash, accretionary lapilli-bearing, and finely laminated. Grain size versus shape data show a range of values that demonstrate most grains are dense, smooth, and equant, in alignment with lithic clasts dominating the tephra componentry. The fine grained and accretionary lapilli-bearing nature of some of these lithofacies confirms that water influenced the style of the explosions. However, we also note juvenile clasts within many of the tephra layers, indicating that many of the layers were formed during phreatomagmatic explosions (sensu stricto), despite the eruptive mechanism being dominantly phreatic. Juvenile clasts are more abundant higher in the tephra profiles, suggesting that juvenile magma was more involved later in the explosive sequence. Thermal and hydrologic modeling indicate that groundwater inflow into a short-lived, small-diameter volcanic conduit (10-m to 120-m-diameter used for modeling) during the 78–85 days preceding the first explosion provides a physically plausible mechanism for this eruptive sequence.

Hawaii↗
USGS2003

Water-quality changes and organic-carbon characterization during recharge with recycled water at a research basin in Montebello Forebay, Los Angeles County, California, 1991-1996

During the early 1990s, the U.S. Geological Survey (USGS) investigated water-quality changes that occur in treated municipal wastewater (recycled water) at a small research basin constructed in the Montebello Forebay of the Central Ground-Water Basin in south-central Los Angeles County. The instrumented research basin is located on a 1/2-acre site at the upgradient end of the San Gabriel River Coastal Spreading Grounds where recharge has been augmented using recycled water since 1961. The facility was used to measure attenuation in selected constituents as recycled water delivered to the basin percolates downward and moves laterally beneath the basin. Attenuation in aqueous concentration was found to range from 20 to 60 percent for total dissolved nitrogen and was about one-third for dissolved organic carbon (DOC). Isotopic data confirmed permanent loss of nitrogen by denitrification. Detailed investigations showed that there were no large differences in the loss of various components of the DOC at the structural or compound level, although surfactants and their metabolites were abundant and did persist in the subsurface. The DOC of wastewater origin was found to have a lower trihalomethane (THM) formation potential upon chlorination than does organic matter of natural origin from most surface-water sources. The organization of this report into 12 topical chapters, and the report's relation to additional USGS publications from this study, is noted in a preface.

Water-Resources Investigations Report↗
USGS2016

A microbial arsenic cycle in sediments of an acidic mine impoundment: Herman Pit, Clear Lake, California

The involvement of prokaryotes in the redox reactions of arsenic occurring between its +5 [arsenate; As(V)] and +3 [arsenite; As(III)] oxidation states has been well established. Most research to date has focused upon circum-neutral pH environments (e.g., freshwater or estuarine sediments) or arsenic-rich “extreme” environments like hot springs and soda lakes. In contrast, relatively little work has been conducted in acidic environments. With this in mind we conducted experiments with sediments taken from the Herman Pit, an acid mine drainage impoundment of a former mercury (cinnabar) mine. Due to the large adsorptive capacity of the abundant Fe(III)-rich minerals, we were unable to initially detect in solution either As(V) or As(III) added to the aqueous phase of live sediment slurries or autoclaved controls, although the former consumed added electron donors (i.e., lactate, acetate, hydrogen), while the latter did not. This prompted us to conduct further experiments with diluted slurries using the live materials from the first incubation as inoculum. In these experiments we observed reduction of As(V) to As(III) under anoxic conditions and reduction rates were enhanced by addition of electron donors. We also observed oxidation of As(III) to As(V) in oxic slurries as well as in anoxic slurries amended with nitrate. We noted an acid-tolerant trend for sediment slurries in the cases of As(III) oxidation (aerobic and anaerobic) as well as for anaerobic As(V) reduction. These observations indicate the presence of a viable microbial arsenic redox cycle in the sediments of this extreme environment, a result reinforced by the successful amplification of arsenic functional genes ( aioA , and arrA ) from these materials.

California↗
USGS2025

Points of consensus on catch-and-release: Considerations for science, ethics, and fisheries management

Catch-and-release (C&R), whether via regulations or voluntary actions, is typically employed with the intent of reducing ­fishing mortality while maintaining recreational angling opportunities (Isermann & Paukert, 2010), but there has been significant discourse about the relative importance of individual-level (see Cooke et al., 2025) vs. population-level (see Corsi et al., 2025) effects of C&R. We hope to offer the angling, scientific, and management communities some points of consensus from which this multifaceted dialogue on C&R can productively build. We preface this by noting that our collective views were informed by this process and the opportunity to share and learn from each other. What is apparent from this exercise is the value of embracing a holistic, cooperative approach. From a regulatory perspective, C&R is typically implemented in high-effort fisheries that are popular due to the quality of the fishing. Catch-and-release regulations are also applied in fisheries where populations have declined and fishing mortality is thought or, most appropriately, known to be a limiting factor for the population. When practiced voluntarily, anglers engaging in C&R can be characterized by high avidity and specialization, and angling is often a central component of their identity (e.g., Fisher, 1997). Due to their passion, avid anglers tend to spotlight the ethical, scientific, and regulatory considerations of C&R. As such, there is a need in fisheries management and science to understand in what situations these considerations transcend biological scales and how to navigate the gamut of voluntary actions and regulatory mandates. In this essay, we offer a distillation of the emergent consensus concepts that we hope managers and researchers will consider at both individual and population scales for legal, ethical, and scientific deliberations.

Fisheries↗
USGS1991

A note on the frictional strength of laumontite from Cajon Pass, California

Laumontite mineralization is pervasive in joints and shear zones encountered in the Cajon Pass drillhole in southern California. In order to determine whether a gouge composed of this hydrated mineral affects shear strength in a manner similar to low-strength, clay-rich fault gouges, frictional sliding experiments were performed under dry, saturated and high pore pressure conditions at effective pressures up to 450 MPa. Coefficients of friction ranged between 0.66 and 0.84, consistent with most crustal rocks and well above the values typical of clay-rich San Andreas fault gouges. Saturation state had no effect on strength or sliding stability. These results suggest that the presence of laumontite in shear zones at Cajon Pass will not affect the shear strength of the rock in a way that can account for the inferred low ambient shear stresses. -Authors

Geophysical Research Letters↗
USGS2015

Ecological effects of the harvest phase of geoduck clam (Panopea generosa Gould, 1850) aquaculture on infaunal communities in southern Puget Sound, Washington USA.

Intertidal aquaculture for geoducks ( Panopea generosa Gould, 1850) is expanding in southern Puget Sound, Washington, where gently sloping sandy beaches are used for field culture. Geoduck aquaculture contributes significantly to the regional economy, but has become controversial because of a range of unresolved questions involving potential biological impacts on marine ecosystems. From 2008 through 2012, the authors used a “before-after-control-impact” experimental design, emphasizing spatial scales comparable with those used by geoduck culturists to evaluate the effects of harvesting market-ready geoducks on associated benthic infaunal communities. Infauna were sampled at three different study locations in southern Puget Sound at monthly intervals before, during, and after harvests of clams, and along extralimital transects extending away from the edges of cultured plots to assess the effects of harvest activities in adjacent uncultured habitat. Using multivariate statistical approaches, strong seasonal and spatial signals in patterns of abundance were found, but there was scant evidence of effects on the community structure associated with geoduck harvest disturbances within cultured plots. Likewise, no indications of significant “spillover” effects of harvest on uncultured habitat adjacent to cultured plots were noted. Complementary univariate approaches revealed little evidence of harvest effects on infaunal biodiversity and indications of modest effects on populations of individual infaunal taxa. Of 10 common taxa analyzed, only three showed evidence of reduced densities, although minor, after harvests whereas the remaining seven taxa indicated either neutral responses to harvest disturbances or increased abundance either during or in the months after harvest events. It is suggested that a relatively active natural disturbance regime, including both small-scale and large-scale events that occur with comparable intensity but more frequently than geoduck harvest events in cultured plots, has facilitated assemblage-level infaunal resistance and resilience to harvest disturbances.

Washington↗
USGS2010

Mercury monitoring in fish using a non-lethal tissue biopsy method

The occurrence of mercury in fish is well-known and often occurs at levels that warrant restricted consumption by sensitive human populations. Because of this, local wildlife and health agencies have developed monitoring programs to identify the magnitude of fish contamination and changes through time. Monitoring mercury levels in fish typically requires killing fish for removal of a fillet. Recently, researchers have proposed the use of a non-lethal tissue biopsy plug method as a surrogate for analysis of the entire fillet. A non-lethal method is particularly desirable for sampling rare or endangered fish or highly valued fisheries. The Missouri Department of Conservation manages several fisheries where the public is sensitive to excessive fish removal, yet there is a desire for mercury information. One such example is the trophy smallmouth bass (Micropterus dolomieu) fishery in the Ozark’s Eleven Point River. Plug removal is not expected to affect fish survival in the shortterm. However, limited information is available on survival of fish for weeks or months after plug removal.

Missouri↗
USGS1953

The use of soils and paleosols for interpreting geomorphic and climatic history of arid regions

The study of modern surface soils, and ancient weathering zones, which occur either buried or as surface relicts, has contributed materially to understanding the complex events of the glacial and post-glacial period both in glaciated areas and in regions not influenced by glaciation. Most work of this kind in the United States has been done by geologists. Numerous Pleistocene geologists have noted weathered zones between sheets of glacial drift or loess in the middle western United States. These include Condra, et al 5 ; Frye 7 ; Frye and Leonard 8 ; Kay and Pearce 13 ; Leighton and MacClintock 15 ; Leverett 16 , 17 , 18 ; Lugn 19 ; Peltier 23 ; Schultz and Stout 26 ; Schultz, et al 27 ; and Simonson 28 . Kay and Pearce 13 interpreted the weathered zones between sheets of glacial drift as profiles of ancient soils which they referred to as gumbotil. Hseung, Marshall and Krusekopf 10 have recently questioned the pedogenic character of gumbotil, but have failed to offer a satisfactory alternative explanation. Thorp, and coworkers 30 , in a general review of buried soils, apparently consider gumbotil a product of ancient soil-forming processes.

Research Council of Israel Special Publication↗
USGS2023

James Tributary summary: A summary of trends in tidal water quality and associated factors, 1985-2021

The James Tributary Summary outlines change over time for a suite of monitored tidal water quality parameters and associated potential drivers of those trends for the period 1985 – 2021 and provides a brief description of the current state of knowledge explaining these observed changes. Water quality parameters described include surface (above pycnocline) total nitrogen (TN), surface total phosphorus (TP), surface water temperature (WTEMP), spring and summer (June, July, August) surface chlorophyll a, summer bottom (below pycnocline) dissolved oxygen (DO) concentrations, and Secchi disk depth (a measure of water clarity). Results for annual bottom TP, bottom TN, surface ortho-phosphate (PO4), surface dissolved inorganic nitrogen (DIN), surface total suspended solids (TSS), and summer surface DO concentrations are provided in an Appendix. Drivers discussed include physiographic watershed characteristics, changes in TN, TP, and sediment loads from the watershed to tidal waters, expected effects of changing land use, and implementation of nutrient management and natural resource conservation practices. Factors internal to estuarine waters that also play a role as drivers are described including biogeochemical processes, physical forces such as wind-driven mixing of the water column and increase in rainfall intensity and volume, and biological factors such as phytoplankton biomass and the presence of submerged aquatic vegetation. Continuing to track water quality response and investigating these influencing factors are important steps to understanding water quality patterns and changes in the James River. The intended audiences for this report include, but are not limited to, 1) technical managers within jurisdictions who are looking at tidal water quality data and trying to understand why patterns are occurring, 2) local watershed organizations that are trying to understand these analyses and working to connect them to their local area(s), and 3) federal, state, and academic researchers. Figure 1 presents a conceptual model highlighting these intended audiences. Our goal is for the Tributary Summary documents to be sources of readily available background for change over time in tidal water quality observed with monitoring data. The intended purpose of the Tributary Summary documents is to help answer questions related to water quality, show how landscape factors drive water quality change over time, provide support for management decisions that may alter water quality trends and living resources conditions, and highlight where there may be information or knowledge gaps.

Virginia↗
USGS2019

Establishing high-frequency noise baselines to 100 Hz based on millions of power spectra from IRIS MUSTANG

Advances in seismic instrumentation have enabled data to be recorded at increasing sample rates. This has in turn created a need to establish higher-frequency baselines for assessing data quality, as the widely-used New High (NHNM) and Low Noise Models (NLNM) of Peterson (1993) do not extend to frequencies above 10 Hz. To provide a baseline for higher frequencies (10-100 Hz), we examine power spectral density probability density functions (PSDPDFs) for high-sample-rate stations available from the Incorporated Research Institutions for Seismology Data Services (IRIS DS) MUSTANG quality control system. We compute high-frequency high and low noise baselines by matching the appropriate composite PSDPDF percentile points to NHNM and NLNM power levels at overlapping frequencies (1-10 Hz) and then extending to higher frequencies (10-100 Hz) with piecewise linear fits to the matching PSDPDF percentile. We find that the Peterson NLNM remains an accurate representation of the lower bound of global ambient Earth noise since it is matched by only 0.1% of Global Seismographic Network (GSN) PSDs. We present high-frequency high and low noise baselines intended primarily for use by temporary networks targeting high-frequency signals (e.g. monitoring of aftershocks or induced seismicity) based on statistics of PSDPDFs from all publicly available high-sample-rate data. Most publicly-available high-sample-rate data is recorded by temporary deployments, and the experiment design and scientific targets of these deployments strongly influence the observed statistical distribution of high-frequency noise. We anticipate that the noise baselines presented here will be useful in automated quality control of high-sample-rate seismic data. However, we note that establishing a low noise model that accurately represents the lowest possible ambient Earth noise at frequencies up to 100 Hz will require additional continuous high-sample-rate data from high-quality permanent stations in low-noise environments.

Bulletin of the Seismological Society of America↗
USGS2011

Occurrence and distribution of Asian carps in Louisiana

In the 1970s, commercial fishers reported sightings of grass carp Ctenopharyngodon idella in large rivers and associated backwaters of Louisiana; the first specimen in Louisiana Department of Wildlife and Fisheries' fishery independent sampling was recorded in 1976. Beginning in the early 1980s, commercial fishers noted increasing populations of bighead carp Hypophthalmichthys nobilis and silver carp H. molitrix (together, the bigheaded carps). Populations of bigheaded carps appear to be increasing at a much slower rate than in the Midwest, possibly due to limited suitability of and access to backwater habitat for juvenile fish. In 2002, harvester reports of sporadic captures of "different-looking" grass carp indicated the possible presence of black carp Mylopharyngodon piceus . Because both normal diploid and triploid (in which triploidy has been induced to cause sterility) black carp have been stocked in the Mississippi basin, determination of the ploidy (number of chromosome sets) of these fishes is important. Since 2002, postmortem ploidy determinations using cells from eyeballs removed from six wild black carp captured in Louisiana showed each to be a normal diploid, indicative of breeding capability and potential reproducing populations. Although reported commercial landings of grass and bigheaded carps have been as high as 34,830 kg/year, limited market demand in past years resulted in many captures being discarded. A protocol for obtaining samples for easily determining ploidy is reported here. Accurate data on Asian carp distributions and their reproductive potential provides information to fisheries researchers that will be constructive in documenting the spread of these invasive species and in the assessment of risk to habitats.

Louisiana↗