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At least 37 records · Page 2Linked to original sources

Minimal changes in heart rate of incubating American Oystercatchers ( Haematopus palliatus ) in response to human activity

An organism's heart rate is commonly used as an indicator of physiological stress due to environmental stimuli. We used heart rate to monitor the physiological response of American Oystercatchers ( Haematopus palliatus ) to human activity in their nesting environment. We placed artificial eggs with embedded microphones in 42 oystercatcher nests to record the heart rate of incubating oystercatchers continuously for up to 27 days. We used continuous video and audio recordings collected simultaneously at the nests to relate physiological response of birds (heart rate) to various types of human activity. We observed military and civilian aircraft, off-road vehicles, and pedestrians around nests. With the exception of high-speed, low-altitude military overflights, we found little evidence that oystercatcher heart rates were influenced by most types of human activity. The low-altitude flights were the only human activity to significantly increase average heart rates of incubating oystercatchers (12% above baseline). Although statistically significant, we do not consider the increase in heart rate during high-speed, low-altitude military overflights to be of biological significance. This noninvasive technique may be appropriate for other studies of stress in nesting birds.

The Condor

Resilience concepts in psychiatry demonstrated with bipolar disorder

Background The term resilience describes stress–response patterns of subjects across scientific disciplines. In ecology, advances have been made to clearly distinguish resilience definitions based on underlying mechanistic assumptions. Engineering resilience (rebound) is used for describing the ability of subjects to recover from adverse conditions (disturbances), and is the rate of recovery. In contrast, the ecological resilience definition considers a systemic change: when complex systems (including humans) respond to disturbances by reorganizing into a new regime (stable state) where structural and functional aspects have fundamentally changed relative to the prior regime. In this context, resilience is an emergent property of complex systems. We argue that both resilience definitions and uses are appropriate in psychology and psychiatry, but although the differences are subtle, the implications and uses are profoundly different. Methods We borrow from the field of ecology to discuss resilience concepts in the mental health sciences. Results In psychology and psychiatry, the prevailing view of resilience is adaptation to, coping with, and recovery (engineering resilience) from adverse social and environmental conditions. Ecological resilience may be useful for describing vulnerability, onset, and the irreversibility patterns of mental disorders. We discuss this in the context of bipolar disorder. Conclusion Rebound, adaptation, and coping are processes that are subsumed within the broader systemic organization of humans, from which ecological resilience emanates. Discerning resilience concepts in psychology and psychiatry has potential for a mechanistically appropriate contextualization of mental disorders at large. This might contribute to a refinement of theory and contextualize clinical practice within the broader systemic functioning of mental illnesses.

International Journal of Bipolar Disorders

Bacterial community diversity and potential eco-physiological roles in toxigenic blooms composed of Microcystis, Aphanizomenon or Planktothrix

Cyanobacterial toxicity, cyanotoxins, and their impact on aquatic ecosystems and human health are well documented. In comparison, less is known about bloom-associated bacterial communities. Co-occurring bacteria can influence bloom development, physiology and collapse, and may also provide a niche for pathogenic bacteria. Existing research focuses on the cyanosphere of Microcystis -dominated blooms, despite the increasing prevalence of filamentous genera ( Aphanizomenon and Planktothrix ). This pilot study aimed to broaden our understanding of the bacterial consortia attached to morphologically distinct cyanobacteria (coccoid and filamentous) dominating phytoplankton communities and to explore their potential roles in amplifying the impacts of cyanobacterial blooms. We investigated four shallow freshwater bodies across three continents and two climate zones: an urban pond in the USA, a dammed reservoir and a natural lake in Poland, and an urban water body in Singapore. Amplicon sequencing (16S rRNA gene) was used to characterize bacterial communities, while shotgun metagenomics identified nitrogen- and phosphorus-cycling genes to infer potential eco-physiological functions. Cyanobacteria dominated bacterioplankton assemblages at all sites (>35.6%), with bloom composition influencing toxigenic profiles. A mixed bloom of Microcystis , Snowella , and Aphanizomenon had the broadest range of cyanotoxin synthetase genes ( mcy E, cyr J, ana F and sxt A). Microcystis blooms correlated with increased Roseomonas , while Planktothrix co-occurred with Flavobacterium – both bacteria likely contribute to nutrient-cycling within blooms and represent potential opportunistic pathogens for aquatic organisms and humans. The Microcystis cyanosphere exhibited the highest number of significant positive correlations with bacteria (19 relations), compared to Planktothrix and Aphanizomenon (11 and 2 relations, respectively). Non-diazotrophic blooms of Microcystis and Planktothrix showed greater abundances of nitrogen – ( ure B, gln A, nar B, and nar HZ) and phosphorus-cycling genes ( pho BHPR and ppk 1), indicating a strong dependence on associated bacteria for nutrient acquisition compared to diazotrophic Aphanizomenon . These findings suggest that Aphanizomenon -dominated blooms may be sustained by simpler microbiomes. Our results provide preliminary evidence of cyanosphere heterogeneity potentially shaped by the dominance or coexistence of three morphologically and eco-physiologically distinct genera of cyanobacteria. A comprehensive knowledge of the taxonomy and functional roles of bloom-associated microbiomes is therefore essential to understand bloom activity, evaluate the environmental threat, and develop effective strategies for prevention and mitigation.

Frontiers in Microbiology

Characterization of Missouri surface waters near point sources of pollution reveals potential novel atmospheric route of exposure for bisphenol A and wastewater hormonal activity pattern

Surface water contamination by chemical pollutants increasingly threatens water quality around the world. Among the many contaminants found in surface water, there is growing concern regarding endocrine disrupting chemicals, based on their ability to interfere with some aspect of hormone action in exposed organisms, including humans. This study assessed water quality at several sites across Missouri (near wastewater treatment plants and airborne release sites of bisphenol A) based on hormone receptor activation potencies and chemical concentrationspresent in the surface water. We hypothesized that bisphenol A and ethinylestradiol would be greater in water near permitted airborne release sites and wastewater treatment plant inputs, respectively, and that these two compounds would be responsible for the majority of activities in receptor-based assays conducted with water collected near these sites. Concentrations of bisphenol A and ethinylestradiol were compared to observed receptor activities using authentic standards to assess contribution to total activities, and quantitation of a comprehensive set of wastewater compounds was performed to better characterize each site. Bisphenol A concentrations were found to be elevated in surface water near permitted airborne release sites, raising questions that airborne releases of BPA may influence nearby surface water contamination and may represent a previously underestimated source to the environment and potential for human exposure. Estrogen and androgen receptor activities of surface water samples were predictive of wastewater input, although the lower sensitivity of the ethinylestradiol ELISA relative to the very high sensitivity of the bioassay approaches did not allow a direct comparison. Wastewater-influenced sites also had elevated anti-estrogenic and anti-androgenic equivalence, while sites without wastewater discharges exhibited no antagonist activities.

Science of the Total Environment

Evolutionary and ecological correlates of thiaminase in fishes

Thiamine (vitamin B 1 ) is required by all living organisms in multiple metabolic pathways. It is scarce in natural systems, and deficiency can lead to reproductive failure, neurological issues, and death. One major cause of thiamine deficiency is an overreliance on diet items containing the enzyme thiaminase. Thiaminase activity has been noted in many prey fishes and linked to cohort failure in salmonid predators that eat prey fish with thiaminase activity, yet it is generally unknown whether evolutionary history, fish traits, and/or environmental conditions lead to production of thiaminase. We conducted literature and GenBank BLAST sequence searches to collect thiaminase activity data and sequence homology data in expressed protein sequences for 300 freshwater and marine fishes. We then tested whether presence or absence of thiaminase could be predicted by evolutionary relationships, trophic level, omega-3 fatty acid concentrations, habitat, climate, invasive potential, and body size. There was no evolutionary relationship with thiaminase activity. It first appears in Class Actinoptergyii (bony ray-finned fishes) and is present across the entire Actinoptergyii phylogeny in both primitive and derived fish orders. Instead, ecological factors explained the most variation in thiaminase: fishes were more likely to express thiaminase if they fed closer to the base of the food web, were high in polyunsaturated fatty acids, lived in freshwater, and were from tropical climates. These data provide a foundation for understanding sources of thiaminase leading to thiamine deficiency in fisheries and other organisms, including humans that eat uncooked fish.

Scientific Reports

The precarious position of wildlife conservation funding in the United States

The Pittman-Robertson Act was established in 1937 to fund state-based wildlife conservation through an existing excise tax on sporting arms and ammunition. Because these items were purchased mostly by hunters at the time, they were the user group primarily funding wildlife conservation. Subsequent amendments to Pittman-Robertson expanded the taxable items to include pistols, revolvers, and archery equipment, effectively broadening the pool of conservation funding contributors to include non-hunters. The continuing trends of declining hunting participation, increasing handgun sales for non-hunting purposes, and increasing sport shooting and target archery independent of hunting, mean that non-hunters are contributing a disproportionately greater amount to Pittman-Robertson funding than hunters, and therefore contributing more to wildlife conservation. The evolving sources of revenue to Pittman-Robertson pose several threats to this historically important source of conservation funding. Addressing them may require new funding coalitions and outreach describing the conservation benefits and outcomes of Pittman-Robertson funding.

Human Dimensions of Wildlife

A decade of Indigenous knowledge research in the Yukon River basin: Reflection on “Indigenous observations of change in the lower Yukon River basin, Alaska”

Herman-Mercer reflects on her first article" Indigenous Observations of Change in the Lower Yukon River Basin, Alaska." The observations and knowledge presented in this study have become part of an ever-growing catalog of studies representing, and part of a chorus of Indigenous communities across the Arctic and Subarctic conveying, the impacts of climate change in this region. The broad observations of environmental change reported in Indigenous Observations 2011, including impacts to subsistence and safety, are more dire and apparent than ten years ago when this article was published. Instances of diseased salmon continue to be reported by subsistence fishers, and the salmon runs have declined so severely since Indigenous Observations 2011 was published that there have been several years in which the commercial and or the subsistence salmon fishery was closed on the Yukon River, with impacts to household economies, food security, and culture. The then-new dangers associated with travel on river ice continue to be a concern across the Yukon River where the thinner river ice and inconsistent freeze up and break up have become the norm.

Alaska

Indigenous observations of climate change in the Lower Yukon River Basin, Alaska

Natural science climate change studies have led to an overwhelming amount of evidence that the Arctic and Subarctic are among the world's first locations to begin experiencing climate change. Indigenous knowledge of northern regions is a valuable resource to assess the effects of climate change on the people and the landscape. Most studies, however, have focused on coastal Arctic and Subarctic communities with relatively little focus on inland communities. This paper relates the findings from fieldwork conducted in the Lower Yukon River Basin of Alaska in the spring of 2009. Semi-structured interviews were conducted with hunters and elders in the villages of St. Mary's and Pitka's Point, Alaska to document observations of climate change. This study assumes that scientific findings and indigenous knowledge are complementary and seeks to overcome the false dichotomy that these two ways of knowing are in opposition. The observed changes in the climate communicated by the hunters and elders of St. Mary's and Pitka's Point, Alaska are impacting the community in ways ranging from subsistence (shifting flora and fauna patterns), concerns about safety (unpredictable weather patterns and dangerous ice conditions), and a changing resource base (increased reliance on fossil fuels). Here we attempt to address the challenges of integrating these two ways of knowing while relating indigenous observations as described by elders and hunters of the study area to those described by scientific literature.

Human Organization

Presence and distribution of organic wastewater compounds in wastewater, surface, ground, and drinking waters, Minnesota, 2000-02

Selected organic wastewater compounds (OWCs) such as household, industrial, and agricultural-use compounds, pharmaceuticals, antibiotics, and sterols and hormones were measured at 65 sites in Minnesota as part of a cooperative study among the Minnesota Department of Health, Minnesota Pollution Control Agency, and the U.S. Geological Survey. Samples were collected in Minnesota during October 2000 through November 2002 and analyzed for the presence and distribution of 91 OWCs at sites including wastewater treatment plant influent and effluent; landfill and feedlot lagoon leachate; surface water; ground water (underlying sewered and unsewered mixed urban land use, a waste dump, and feedlots); and the intake and finished drinking water from drinking water facilities. There were 74 OWCs detected that represent a wide variety of use. Samples generally comprised a mixture of compounds (average of 6 OWCs) and 90 percent of the samples had at least one OWC detected. Concentrations for detected OWCs generally were less than 3 micrograms per liter. The ten most frequently detected OWCs were metolachlor (agricultural-use herbicide); cholesterol (sterol primarily associated with animal waste); caffeine (stimulant), N,N-diethyl- meta -toluamide (DEET) (topical insect repellant); bromoform (disinfection by product); tri(2-chloroethyl)phosphate (flame-retardant and plastic component); beta -sitosterol (plant sterol that is a known endocrine disruptor); acetyl-hexamethyl-tetrahydro- naphthalene (AHTN) (synthetic musk widely used in personal care products, and a known endocrine disruptor); bisphenol-A (plastic component and a known endocrine disruptor); and cotinine (metabolite of nicotine). Wastewater treatment plant influent and effluent, landfill leachate, and ground water underlying a waste dump had the greatest number of OWCs detected. OWC detections in ground-water were low except underlying the one waste dump studied and feedlots. There generally were more OWCs detected in surface water than ground water, and there were twice as many OWCs detected in the surface water sites downstream from wastewater treatment plant (WWTP effluent than at sites not directly downstream from effluent. Comparisons among site classifications apply only to sites sampled during the study. Results of this study indicate ubiquitous distribution of measured OWCs in the environment that originate from numerous sources and pathways. During this reconnaissance of OWCs in Minnesota it was not possible to determine the specific sources of OWCs to surface, ground, or drinking waters. The data indicate WWTP effluent is a major pathway of OWCs to surface waters and that landfill leachate at selected facilities is a potential source of OWCs to WWTPs. Aquatic organism or human exposure to some OWCs is likely based on OWC distribution. Few aquatic or human health standards or criteria exist for the OWCs analyzed, and the risks to humans or aquatic wildlife are not known. Some OWCs detected in this study are endocrine disrupters and have been found to disrupt or influence endocrine function in fish. Thirteen endocrine disrupters, 3- tert -butyl-4-hydoxyanisole (BHA), 4- cumylphenol, 4- normal -octylphenol, 4- tert -octylphenol, acetyl-hexamethyl-tetrahydro-naphthalene (AHTN), benzo[α]pyrene, beta-sitosterol, bisphenol-A, diazinon, nonylphenol diethoxylate (NP2EO), octyphenol diethoxylate (OP2EO), octylphenol monoethoxylate (OP1EO), and total para -nonylphenol (NP) were detected. Results of reconnaissance studies may help regulators who set water-quality standards begin to prioritize which OWCs to focus upon for given categories of water use.

Minnesota

Effects of Abandoned Coal-Mine Drainage on Streamflow and Water Quality in the Mahanoy Creek Basin, Schuylkill, Columbia, and Northumberland Counties, Pennsylvania, 2001

This report assesses the contaminant loading, effects to receiving streams, and possible remedial alternatives for abandoned mine drainage (AMD) within the Mahanoy Creek Basin in east-central Pennsylvania. The Mahanoy Creek Basin encompasses an area of 157 square miles (407 square kilometers) including approximately 42 square miles (109 square kilometers) underlain by the Western Middle Anthracite Field. As a result of more than 150 years of anthracite mining in the basin, ground water, surface water, and streambed sediments have been adversely affected. Leakage from streams to underground mines and elevated concentrations (above background levels) of acidity, metals, and sulfate in the AMD from flooded underground mines and (or) unreclaimed culm (waste rock) degrade the aquatic ecosystem and impair uses of the main stem of Mahanoy Creek from its headwaters to its mouth on the Susquehanna River. Various tributaries also are affected, including North Mahanoy Creek, Waste House Run, Shenandoah Creek, Zerbe Run, and two unnamed tributaries locally called Big Mine Run and Big Run. The Little Mahanoy Creek and Schwaben Creek are the only major tributaries not affected by mining. To assess the current hydrological and chemical characteristics of the AMD and its effect on receiving streams, and to identify possible remedial alternatives, the U.S. Geological Survey (USGS) began a study in 2001, in cooperation with the Pennsylvania Department of Environmental Protection and the Schuylkill Conservation District. Aquatic ecological surveys were conducted by the USGS at five stream sites during low base-flow conditions in October 2001. Twenty species of fish were identified in Schwaben Creek near Red Cross, which drains an unmined area of 22.7 square miles (58.8 square kilometers) in the lower part of the Mahanoy Creek Basin. In contrast, 14 species of fish were identified in Mahanoy Creek near its mouth at Kneass, below Schwaben Creek. The diversity and abundance of fish species in Mahanoy Creek decreased progressively upstream from 13 species at Gowen City to only 2 species each at Ashland and Girardville. White sucker (Catostomus commersoni), a pollution-tolerant species, was present at each of the surveyed reaches. The presence of fish at Girardville was unexpected because of the poor water quality and iron-encrusted streambed at this location. Generally, macroinvertebrate diversity and abundance at these sites were diminished compared to Schwaben Creek and other tributaries draining unmined basins, consistent with the observed quality of streamwater and streambed sediment. Data on the flow rate and chemistry for 35 AMD sources and 31 stream sites throughout the Mahanoy Creek Basin were collected by the USGS during high base-flow conditions in March 2001 and low base-flow conditions in August 2001. A majority of the base-flow streamwater samples met water-quality standards for pH (6.0 to 9.0); however, few samples downstream from AMD sources met criteria for acidity less than alkalinity (net alkalinity = 20 milligrams per liter as CaCO3) and concentrations of dissolved iron (0.3 milligram per liter) and total manganese (1.0 milligram per liter). Iron, aluminum, and various trace elements including cobalt, copper, lead, nickel, and zinc, were present in many streamwater samples at concentrations at which continuous exposure can not be tolerated by aquatic organisms without an unacceptable effect. Furthermore, concentrations of sulfate, iron, manganese, aluminum, and (or) beryllium in some samples exceeded drinking-water standards. Other trace elements, including antimony, arsenic, barium, cadmium, chromium, selenium, silver, and thallium, did not exceed water-quality criteria for protection of aquatic organisms or human health. Nevertheless, when considered together, concentrations of iron, manganese, arsenic, cadmium, chromium, copper, lead, nickel, and zinc in a majority of the streambed sediment samples from Mahanoy Creek and

Scientific Investigations Report

Toxic algae in inland waters of the conterminous United States—A review and synthesis

Cyanobacteria are the most common toxigenic algae in inland waters. Their toxins can affect the health of aquatic and terrestrial organisms, including humans. Other algal groups, such as haptophytes (e.g., Prymnesium parvum ) and euglenoids (e.g., Euglena sanguinea ), can also form harmful algal blooms (HABs) whose toxins cause injury to aquatic biota but currently have no known effects on human health. Prymnesium parvum , however, is responsible for some of the worst HAB-related ecological disasters recorded in inland waters. Here, we provide an overview of the primary toxigenic algae found in U.S. inland waters: cyanobacteria (planktonic forms), P. parvum , and E. sanguinea with the objective of describing their similarities and differences in the areas of HAB ecology, algal toxins, and the potential for future range expansion of HABs. A detailed account of bloom habitats and their known associations with land cover and use is provided from the perspective of water quality. This review revealed that salinity may have an influence on inland cyanobacterial blooms and cyanotoxins that had not been fully recognized previously.

Water

Integrated science for the study of microplastics in the environment—A strategic science vision for the U.S. Geological Survey

Executive Summary Evidence of the widespread occurrence of microplastics throughout our environment and exposure to humans and other organisms over the past decade has led to questions about the possibility of health hazards and mitigation of exposures. This document discusses nanoplastics as well as microplastics (referred to solely as microplastics); the microplastics have a range from 1 micrometer to 5 millimeters (1 μm–5 mm) in length, whereas the nanoplastics are less than 1 μm in length (sidebar ES1). A myriad of environmental exposure pathways with microplastics to humans and wildlife, including ingestion, inhalation, and bodily absorption, are likely to exist. A growing body of evidence has documented bioaccumulation of microplastics in tissues and organs of humans and wildlife, benthic community effects, and potential nutritional and reproductive effects in some wildlife species. Understanding if or when environmental exposures pose a health risk is complicated by the diversity of microplastic sizes, morphologies, polymer types, and chemicals added during manufacturing or sorbed from the environment; ongoing challenges in analytical methods used to detect, quantify, and characterize microplastics and associated chemicals in our ecosystems; and the fact that ecotoxicological studies regarding microplastics are still in their infancy. Therefore, the study of environmental exposures and potential related health hazards of microplastics to the public and wildlife is a One Health (sidebar ES2) research topic that necessitates integrated science approaches. A better understanding of the sources, pathways, fate, and biological effects of microplastics has become a priority of the Federal Government, State governments, Tribes, stakeholders, and the public. Examples of Federal and State microplasticfocused legislation and programs to prioritize microplastic research and reduction include the Federal Microbead-Free Waters Act of 2015, California Senate Bills 1422 and 1263 (2018), the U.S. Environmental Protection Agency (EPA) Trash Free Waters Program, the National Institute of Standards and Technology’s Microplastic and Nanoplastic Metrology project, and Minnesota’s microplastic project. With its unique expertise and capabilities, the U.S. Geological Survey (USGS) is well positioned to help fill some of the most important microplastic science gaps. This strategic science vision document for microplastics identifies current (2023) microplastic science gaps and prioritizes research relevant to the mission, expertise, and capabilities of the USGS. It is intended for USGS scientists and stakeholders to use as a starting point for planning, prioritizing, and designing collaborative environmental microplastic science. Many of the microplastic science gaps and priorities are scalable, from local to national, and thus, can be made commensurate with available funding and evolving analytical and field tools, laboratory capacity, and stakeholder needs. Current (2023) or future research by academia and other Federal or State agencies, and Tribes may be aimed at some of the same microplastic science gaps identified in this document. Therefore, this document can be used as an information resource to maximize strengths and capabilities and minimize redundancy in communication and collaboration.

Circular

Assessing the biological reactivity of organic compounds on volcanic ash: Implications for human health hazard

Exposure to volcanic ash is a long-standing health concern for people living near active volcanoes and in distal urban areas. During transport and deposition, ash is subjected to various physicochemical processes that may change its surface composition and, consequently, bioreactivity. One such process is the interaction with anthropogenic pollutants; however, the potential for adsorbed, deleterious organic compounds to directly impact human health is unknown. We use an in vitro bioanalytical approach to screen for the presence of organic compounds of toxicological concern on ash surfaces and assess their biological potency. These compounds include polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dlPCBs). Analysis of ash collected in or near urbanised areas at five active volcanoes across the world (Etna, Italy; Fuego, Guatemala; Kelud, Indonesia; Sakurajima, Japan; Tungurahua, Ecuador) using the bioassay inferred the presence of such compounds on all samples. A relatively low response to PCDD/Fs and the absence of a dlPCBs response in the bioassay suggest that the measured activity is dominated by PAHs and PAH-like compounds. This study is the first to demonstrate a biological potency of organic pollutants associated with volcanic ash particles. According to our estimations, they are present in quantities below recommended exposure limits and likely pose a low direct concern for human health.

Bulletin of Volcanology

Modeling the human invader in the United States

Modern biogeographers recognize that humans are seen as constituents of ecosystems, drivers of significant change, and perhaps, the most invasive species on earth. We found it instructive to model humans as invasive organisms with the same environmental factors. We present a preliminary model of the spread of modern humans in the conterminous United States between 1992 and 2001 based on a subset of National Land Cover Data (NLCD), a time series LANDSAT product. We relied on the commonly used Maxent model, a species-environmental matching model, to map urbanization. Results: Urban areas represented 5.1% of the lower 48 states in 2001, an increase of 7.5% (18,112 km 2 ) in the nine year period. At this rate, an area the size of Massachusetts is converted to urban land use every ten years. We used accepted models commonly used for mapping plant and animal distributions and found that climatic and environmental factors can strongly predict our spread (i.e., the conversion of forests, shrub/grass, and wetland areas into urban areas), with a 92.5% success rate (Area Under the Curve). Adding a roads layer in the model improved predictions to a 95.5% success rate. 8.8% of the 1-km 2 > cells in the conterminous U.S. now have a major road in them. In 2001, 0.8% of 1-km 2 > cells in the U.S. had an urbanness value of > 800, (>89% of a 1-km 2 > cell is urban), while we predict that 24.5% of 1-km 2 > cells in the conterminous U.S. will be > 800 eventually. Main conclusion: Humans have a highly predictable pattern of urbanization based on climatic and topographic variables. Conservation strategies may benefit from that predictability.

Journal of Applied Remote Sensing

Manganese

Manganese is an essential element for modern industrial societies. Its principal use is in steelmaking, where it serves as a purifying agent in iron-ore refining and as an alloy that converts iron into steel. Although the amount of manganese consumed to make a ton of steel is small, ranging from 6 to 9 kilograms, it is an irreplaceable component in the production of this fundamental material. The United States has been totally reliant on imports of manganese for many decades and will continue to be so for at least the near future. There are no domestic reserves, and although some large low-grade resources are known, they are far inferior to manganese ores readily available on the international market. World reserves of manganese are about 630 million metric tons, and annual global consumption is about 16 million metric tons. Current reserves are adequate to meet global demand for several decades. Global resources in traditional land-based deposits, including both reserves and rocks sufficiently enriched in manganese to be ores in the future, are much larger, at about 17 billion metric tons. Manganese resources in seabed deposits of ferromanganese nodules and crusts are larger than those on land and have not been fully quantified. No production from seabed deposits has yet been done, but current research and development activities are substantial and may bring parts of these seabed resources into production in the future. The advent of economically successful seabed mining could substantially alter the current scenario of manganese supply by providing a large new source of manganese in addition to traditional land-based deposits. From a purely geologic perspective, there is no global shortage of proven ores and potential new ores that could be developed from the vast tonnage of identified resources. Reserves and resources are very unevenly distributed, however. The Kalahari manganese district in South Africa contains 70 percent of the world’s identified resources and about 25 percent of its reserves. South Africa, Brazil, and Ukraine together accounted for nearly 65 percent of reserves in 2013. The combination of total import reliance for manganese, the mineral commodity’s essential uses in our industrialized society, and the potential for supply disruptions because of the limited sources of the ore makes manganese among the most critical minerals for the United States. Manganese is the 12th most abundant element in Earth’s crust. Its concentration varies among common types of rocks, mostly in the range of from 0.1 to 0.2 percent. The highest quality manganese ores contain from 40 to 45 percent manganese. The formation of these ores requires specialized geologic conditions that concentrate manganese at several hundred times its average crustal abundance. The dominant processes in forming the world’s principal deposits take place in the oceans. As a result, most important manganese deposits occur in ancient marine sedimentary rocks that are now exposed on continents as a result of subsequent tectonic uplift and erosion. In many cases, other processes have further enriched these manganiferous sedimentary rocks to form some of today’s highest grade ores. Modern seabed resources of ferromanganese nodules cover vast areas of the present ocean floor and are still forming by complex interactions of marine microorganisms, manganese dissolved in seawater, and chemical processes on the seabed. Manganese is ubiquitous in soil, water, and air. It occurs most often in solid form but can become soluble under acidic conditions. Manganese mining, like any activity that disturbs large areas of Earth’s surface, has the potential to produce increases in manganese concentrations that could be harmful to humans or the environment if not properly controlled. Although manganese is an essential nutrient for humans and most other organisms, overexposure can lead to neurotoxicity in humans. Workers at manganese mining and processing facilities have the greatest potential to inhale manganese-rich dust. Without proper protective equipment, these workers may develop a permanent neurological disorder known as manganism. Each manganese mine is unique and presents its own suite of potential hazards and preventative measures. Likewise, various nations have their own sets of standards to ensure safe mining, isolation of mine waste, treatment of mine waters, and mine closure and restoration. Interest in mining trace metals contained in ferromanganese nodules and crusts on the seabed has increased rapidly in the past decade. Prime areas for future research include overcoming the technological challenges presented by mining as deep as 6,500 meters below sea level and understanding and mitigating the potential impacts of seabed mining on marine ecosystems.

Professional Paper

Sediment quality in the north coastal basin of Massachusetts, 2003

The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, completed a reconnaissance-level study of bottom-sediment quality in selected lakes, rivers, and estuaries in the North Coastal Basin of Massachusetts. Bottom-sediment grab samples were collected from 20 sites in the North River, Lake Quannapowitt, Saugus River, Mill River, Shute Brook, Sea Plane Basin, Pines River, and Bear Creek. The samples were tested for various types of potentially harmful contaminants? including 33 elements, 17 polyaromatic hydrocarbons (PAHs), 22 organochlorine pesticides, and 7 polychlorinated biphenyl (PCB) mixtures (Aroclors)?to benthic organisms (bottom-dwelling) and humans. The results were compared among sampling sites, to background concentrations, and to concen-trations measured in other urban rivers, and sediment-quality guidelines were used to predict toxicity at the sampling sites to benthic organisms and humans. Because there are no standards for human toxicity for aquatic sediment, standards for contaminated upland soil were used. Contaminant concentrations measured in sediment collected from the North Coastal Basin generally were equal to or greater than concentrations in sediment from uncontaminated rivers throughout New England. Contaminants in North Coastal Basin sediment with elevated concentrations (above back-ground levels) included arsenic, chromium, copper, lead, nickel, and zinc, some of the PAHs, dichlorodiphenyltrichloro-ethane (DDT) and its metabolites, and dieldrin. No PCBs were measured above the detection limits. Measured concentrations of arsenic, chromium, and lead were also generally greater than those measured in other urban rivers throughout the conter-minous United States. With one exception (arsenic), local con-centrations measured in sediment samples collected from the North Coastal Basin were lower than concentrations measured in sediment collected from two of three urban rivers draining to Boston Harbor. The probable toxicity to benthic organisms ranged from about 33 to 91 percent across the study area. Of the elements analyzed, antimony, arsenic, beryllium, and lead exceeded the soil standards for risk to human health. Of the PAHs analyzed, four also exceeded soil standards. Organochlorine pesticide concentrations, however, were not high enough relative to the soil standards to pose a risk to human health. Some trace element and some organic compound concentrations in bottom sediment may be toxic to aquatic organisms and may pose a risk to human health.

Scientific Investigations Report

Genetic responses to rapid change in the environment during the anthropocene

Humans have greatly affected the genetic composition of many different organisms during the Anthropocene. Humans cause genetic changes by affecting the direction and magnitude of evolutionary forces that act to create the Earth's biota. In many cases, we expect the outcome of human actions to be extinction and hybridization of existing species, but other outcomes, such as adaptation, also occur. Given the reach of humans throughout the globe, and recent biotechnology advances that make it possible to move individual genes between species or to remove them, it is likely that human influence on the genetic composition of other organisms will become even more widespread as the Anthropocene progresses.

Book chapter

Microphotographs of cyanobacteria documenting the effects of various cell-lysis techniques

Cyanotoxins are a group of organic compounds biosynthesized intracellularly by many species of cyanobacteria found in surface water. The United States Environmental Protection Agency has listed cyanotoxins on the Safe Drinking Water Act's Contaminant Candidate List 3 for consideration for future regulation to protect public health. Cyanotoxins also pose a risk to humans and other organisms in a variety of other exposure scenarios. Accurate and precise analytical measurements of cyanotoxins are critical to the evaluation of concentrations in surface water to address the human health and ecosystem effects. A common approach to total cyanotoxin measurement involves cell membrane disruption to release the cyanotoxins to the dissolved phase followed by filtration to remove cellular debris. Several methods have been used historically, however no standard protocols exist to ensure this process is consistent between laboratories before the dissolved phase is measured by an analytical technique for cyanotoxin identification and quantitation. No systematic evaluation has been conducted comparing the multiple laboratory sample processing techniques for physical disruption of cell membrane or cyanotoxins recovery. Surface water samples collected from lakes, reservoirs, and rivers containing mixed assemblages of organisms dominated by cyanobacteria, as well as laboratory cultures of species-specific cyanobacteria, were used as part of this study evaluating multiple laboratory cell-lysis techniques in partnership with the U.S. Environmental Protection Agency. Evaluated extraction techniques included boiling, autoclaving, sonication, chemical treatment, and freeze-thaw. Both treated and untreated samples were evaluated for cell membrane integrity microscopically via light, epifluorescence, and epifluorescence in the presence of a DNA stain. The DNA stain, which does not permeate live cells with intact membrane structures, was used as an indicator for cyanotoxin release into the dissolved phase. Of the five techniques, sonication (at 70 percent) was most effective at complete cell destruction while QuikLyse (Trademarked) was least effective. Autoclaving, boiling, and sequential freeze-thaw were moderately effective in physical destruction of colonies and filaments.

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