Results for “Research Contributions” — Page 49

USGS2025

U.S. Geological Survey science strategy to address white-nose syndrome and bat health in 2025–2029

Since its discovery in 2006, the fungal disease known as white-nose syndrome (WNS) has killed millions of bats. Of the 47 bat species native to the conterminous United States, Alaska, Hawaii, and Canada, 12 have been affected by WNS, including 3 endangered species and 1 proposed endangered species. WNS has also been detected in 40 States and 9 Canadian Provinces. U.S. Geological Survey (USGS) scientists have been critical in identifying the causal fungus for WNS ( Pseudogymnoascus destructans [Pd]), characterizing the effects of WNS, and tracking the spread of Pd in many bat populations in North America. The mission of the USGS WNS and Bat Health Science Team is to deliver integrated science in order to build resiliency into free-ranging bat populations through more effective WNS management, build capacity for bat health science, and enhance bat health information sharing across USGS science centers and cooperative research units as well as with stakeholders. The USGS can play an important role in supporting regional and national capacity building by providing resources and guidance to local, State, and Tribal management entities and by providing tools to enhance disease management. The USGS Ecosystems Mission Area’s Biological Threats and Invasive Species Research Program is the lead Federal program for free-ranging wildlife disease research and surveillance. As of 2024, guided by the science priorities set by the WNS Steering Committee, USGS scientists are engaged in a nationwide response to WNS. This work is done in close coordination with our partners at the U.S. Fish and Wildlife Service, National Park Service, Bureau of Land Management, U.S. Forest Service of the U.S. Department of Agriculture, U.S. Department of Defense, as well as State and Tribal agencies. In addition to conducting WNS research, the USGS is mapping the spread of WNS and coordinating the North American Bat Monitoring Program (NABat) to understand how WNS and other stressors affect the status and trends of native bats across their range. The USGS is supporting the national WNS response through four science goals: (1) provide situational awareness on the health of bat populations; (2) conduct ecological studies of bats along the gradient of disease vulnerability; (3) contribute actionable science to enhance the resiliency of bat populations; and (4) implement an adaptive, holistic approach to bat health.

Circular↗

USGS1999

U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 1 (Part A)

This report contains papers presented at the seventh Technical Meeting of the U.S. Geological Survey (USGS), Toxic Substances Hydrology (Toxics) Program. The meeting was held March 8-12, 1999, in Charleston, South Carolina. Toxics Program Technical Meetings are held periodically to provide a forum for presentation and discussion of results of recent research activities. The objectives of these meetings are to: Present recent research results to essential stakeholders, Encourage synthesis and integrated interpretations among scientists with different expertise who are working on a contamination issue, and Promote exchange of ideas among scientists working on different projects and issues within the Toxics Program. The Proceedings is published in three volumes. Volume 1 contains papers that report on results of research on contamination from hard-rock mining. Results include research on contamination from hard rock mining in arid southwest alluvial basins, research on hard rock mining in mountainous terrain, and progress from the USGS Abandoned Mine Lands Initiative. This Initiative is designed to develop a watershed-based approach to characterize and remediate contamination from abandoned mine lands and transfer technologies to Federal land management agencies and stakeholders. Volume 2 contains papers on contamination of hydrologic systems and related ecosystems. The papers discuss research on the response of estuarine ecosystems to contamination from human activities. They include research on San Francisco Bay; mercury contamination of aquatic ecosystems; and investigation of the occurrence, distribution, and fate of agricultural chemicals in the Mississippi River Basin. This volume also contains results on development and reconnaissance testing of new methods to detect emerging contaminants in environmental samples. Volume 3 contains papers on subsurface contamination from point sources. The papers discuss research on: hydrocarbons and fuel oxygenates at gasoline release sites; ground-water contamination by crude oil; complex contaminant mixtures from treated wastewater discharges; waste disposal and subsurface transport of contaminants in arid environments; ground water and surface water affected by municipal landfill leachate; natural attenuation of chlorinated solvents; and characterizing flow and transport in fractured rock aquifers. In all, the more than 175 papers contained in this proceedings reflect the contributions of more than 350 scientists who are co-authors. These scientists are from across the USGS, as well as from universities, other Federal and State agencies, and industry.

Water-Resources Investigations Report↗

USGS1999

U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 2 (Part B)

This report contains papers presented at the seventh Technical Meeting of the U.S. Geological Survey (USGS), Toxic Substances Hydrology (Toxics) Program. The meeting was held March 8-12, 1999, in Charleston, South Carolina. Toxics Program Technical Meetings are held periodically to provide a forum for presentation and discussion of results of recent research activities. The objectives of these meetings are to: Present recent research results to essential stakeholders, Encourage synthesis and integrated interpretations among scientists with different expertise who are working on a contamination issue, and Promote exchange of ideas among scientists working on different projects and issues within the Toxics Program. The Proceedings is published in three volumes. Volume 1 contains papers that report on results of research on contamination from hard-rock mining. Results include research on contamination from hard rock mining in arid southwest alluvial basins, research on hard rock mining in mountainous terrain, and progress from the USGS Abandoned Mine Lands Initiative. This Initiative is designed to develop a watershed-based approach to characterize and remediate contamination from abandoned mine lands and transfer technologies to Federal land management agencies and stakeholders. Volume 2 contains papers on contamination of hydrologic systems and related ecosystems. The papers discuss research on the response of estuarine ecosystems to contamination from human activities. They include research on San Francisco Bay; mercury contamination of aquatic ecosystems; and investigation of the occurrence, distribution, and fate of agricultural chemicals in the Mississippi River Basin. This volume also contains results on development and reconnaissance testing of new methods to detect emerging contaminants in environmental samples. Volume 3 contains papers on subsurface contamination from point sources. The papers discuss research on: hydrocarbons and fuel oxygenates at gasoline release sites; ground-water contamination by crude oil; complex contaminant mixtures from treated wastewater discharges; waste disposal and subsurface transport of contaminants in arid environments; ground water and surface water affected by municipal landfill leachate; natural attenuation of chlorinated solvents; and characterizing flow and transport in fractured rock aquifers. In all, the more than 175 papers contained in this proceedings reflect the contributions of more than 350 scientists who are co-authors. These scientists are from across the USGS, as well as from universities, other Federal and State agencies, and industry.

Water-Resources Investigations Report↗

USGS1999

U.S. Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Charleston, South Carolina, March 8-12, 1999: Volume 3 (Part C)

This report contains papers presented at the seventh Technical Meeting of the U.S. Geological Survey (USGS), Toxic Substances Hydrology (Toxics) Program. The meeting was held March 8-12, 1999, in Charleston, South Carolina. Toxics Program Technical Meetings are held periodically to provide a forum for presentation and discussion of results of recent research activities. The objectives of these meetings are to: Present recent research results to essential stakeholders, Encourage synthesis and integrated interpretations among scientists with different expertise who are working on a contamination issue, and Promote exchange of ideas among scientists working on different projects and issues within the Toxics Program. The Proceedings is published in three volumes. Volume 1 contains papers that report on results of research on contamination from hard-rock mining. Results include research on contamination from hard rock mining in arid southwest alluvial basins, research on hard rock mining in mountainous terrain, and progress from the USGS Abandoned Mine Lands Initiative. This Initiative is designed to develop a watershed-based approach to characterize and remediate contamination from abandoned mine lands and transfer technologies to Federal land management agencies and stakeholders. Volume 2 contains papers on contamination of hydrologic systems and related ecosystems. The papers discuss research on the response of estuarine ecosystems to contamination from human activities. They include research on San Francisco Bay; mercury contamination of aquatic ecosystems; and investigation of the occurrence, distribution, and fate of agricultural chemicals in the Mississippi River Basin. This volume also contains results on development and reconnaissance testing of new methods to detect emerging contaminants in environmental samples. Volume 3 contains papers on subsurface contamination from point sources. The papers discuss research on: hydrocarbons and fuel oxygenates at gasoline release sites; ground-water contamination by crude oil; complex contaminant mixtures from treated wastewater discharges; waste disposal and subsurface transport of contaminants in arid environments; ground water and surface water affected by municipal landfill leachate; natural attenuation of chlorinated solvents; and characterizing flow and transport in fractured rock aquifers. In all, the more than 175 papers contained in this proceedings reflect the contributions of more than 350 scientists who are co-authors. These scientists are from across the USGS, as well as from universities, other Federal and State agencies, and industry.

Water-Resources Investigations Report↗

USGS2011

Land use and habitat conditions across the southwestern Wyoming sagebrush steppe: development impacts, management effectiveness and the distribution of invasive plants

For the past several years, USGS has taken a multi-faceted approach to investigating the condition and trends in sagebrush steppe ecosystems. This recent effort builds upon decades of work in semi-arid ecosystems providing a specific, applied focus on the cumulative impacts of expanding human activities across these landscapes. Here, we discuss several on-going projects contributing to these efforts: (1) mapping and monitoring the distribution and condition of shrub steppe communities with local detail at a regional scale, (2) assessing the relationships between specific, land-use features (for example, roads, transmission lines, industrial pads) and invasive plants, including their potential (environmentally defined) distribution across the region, and (3) monitoring the effects of habitat treatments on the ecosystem, including wildlife use and invasive plant abundance. This research is focused on the northern sagebrush steppe, primarily in Wyoming, but also extending into Montana, Colorado, Utah and Idaho. The study area includes a range of sagebrush types (including, Artemisia tridentata ssp. tridentata, Artemisia tridentata ssp. wyomingensis, Artemisia tridentata ssp. vaseyana, Artemisia nova) and other semi-arid shrubland types (for example, Sarcobatus vermiculatus, Atriplex confertifolia, Atriplex gardneri), impacted by extensive interface between steppe ecosystems and industrial energy activities resulting in a revealing multiple-variable analysis. We use a combination of remote sensing (AWiFS (1 Any reference to platforms, data sources, equipment, software, patented or trade-marked methods is for information purposes only. It does not represent endorsement of the U.S.D.I., U.S.G.S. or the authors), Landsat and Quickbird platforms), Geographic Information System (GIS) design and data management, and field-based, replicated sampling to generate multiple scales of data representing the distribution of shrub communities for the habitat inventory. Invasive plant sampling focused on the interaction between human infrastructure and weedy plant distributions in southwestern Wyoming, while also capturing spatial variability associated with growing conditions and management across the region. In a separate but linked study, we also sampled native and invasive composition of recent and historic habitat treatments. Here, we summarize findings of this ongoing work, highlighting patterns and relationships between vegetation (native and invasive), land cover, landform, and land-use patterns in the sagebrush steppe.

Wyoming↗

USGS2014

USGS ecosystem research for the next decade: advancing discovery and application in parks and protected areas through collaboration

Ecosystems within parks and protected areas in the United States and throughout the world are being transformed at an unprecedented rate. Changes associated with natural hazards, greenhouse gas emissions, and increasing demands for water, food, land, energy and mineral resources are placing urgency on sound decision making that will help sustain our Nation’s economic and environmental well-being (Millennium Ecosystem Assessment, 2005). In recognition of the importance of science in making these decisions, the U.S. Geological Survey (USGS) in 2007 identified ecosystem science as one of six science directions included in a comprehensive decadal strategy (USGS 2007). The Ecosystems Mission Area was identified as essential for integrating activity within the USGS and as a key to enhanced integration with other Federal and private sector research and management organizations (Myers at al., 2007). This paper focuses on benefits to parks and protected areas from the USGS Ecosystems Mission Area plan that expanded the scope of the original 2007 science strategy, to identify the Bureau’s work in ecosystem science over the next decade (Williams et al., 2013). The plan describes a framework that encompasses both basic and applied science and allows the USGS to continue to contribute meaningfully to conservation and management issues related to the Nation’s parks and ecological resources. This framework relies on maintaining long-standing, collaborative relationships with partners in both conducting science and applying scientific results. Here we summarize the major components of the USGS Ecosystems Science Strategy, articulating the vision, goals and strategic approaches, then outlining some of the proposed actions that will ultimately prove useful to those managing parks and protected areas. We end with a discussion on the future of ecosystem science for the USGS and how it can be used to evaluate ecosystem change and the associated consequences to management of our Nation’s natural resources.

The George Wright Forum↗

USGS2021

Correspondence analysis for mineral commodity research: An example workflow for mineralized calderas, southwest United States

Historical mine and mineral deposit datasets are routinely used to inform quantitative mineral assessment models, but they also can contain a wealth of supplementary qualitative information that is generally underutilized. We present a workflow that uses correspondence analysis, an exploratory tool commonly applied to multivariate abundance data, to better utilize qualitative data in these historical datasets. The workflow involves extraction of qualitative information on ore mineralogy from a mineral deposit database, attaches those data to a target geological feature, and analyzes the underlying data structure with correspondence analysis and hierarchical clustering. The output of correspondence analysis is inversely weighted to the relative frequency of ore minerals, and therefore rare mineral species (i.e., those with unusually low frequencies) can disproportionately contribute to the total variance of the dataset. We present a novel technique for aggregating frequencies of rare mineral species that minimizes this effect. We apply this workflow to evaluate how ore mineral assemblages in former and active mines vary in spatial relation to silicic calderas in the southwestern United States. The most common ore mineral associations observed spatially and genetically associated to calderas include those related to polymetallic, base metal-rich systems and epithermal Au–Ag systems. Three other groups of mineralized calderas were identified, including: (1) Hg–Sb mineralized calderas in the northern Great Basin and western Nevada volcanic field; (2) calderas associated with elevated abundances of Mn oxides/hydroxides, fluorite, and Be-minerals, mostly in eastern Utah and New Mexico; and (3) calderas with numerous U ± F deposits, which are located in central Colorado, the eastern Great Basin and in northern Nevada. The latter three groups are associated with economically significant critical mineral resources, including the Li resources of the McDermitt complex and Be associated with the Spor Mountain on the margin of the Thomas caldera complex. We conclude that correspondence analysis is a promising technique that can enhance data exploration of the qualitative information held within mineral deposit datasets. Consequently, it could have numerous applications for mineral potential mapping, resource assessment projects, and characterization of mineral systems.

Natural Resources Research↗

USGS2020

Assessment of existing groundwater quality data in the Green-Duwamish watershed, Washington

The United States Geological Survey (USGS) provided technical support to the Washington Department of Ecology (Ecology) in their assessment of the role groundwater plays in contributing pollutant loading to the Green-Duwamish River near Seattle, Washington. Ecology is developing watershed hydrology models of the Green-Duwamish watershed, and need to assign realistic contaminant concentrations to the various Hydrologic Response Units represented in their models. The USGS compiled existing groundwater quality data in the Green-Duwamish watershed, and this report summarizes results and interpretation of the dataset, including identifying data gaps and needs for further research and monitoring. The sources of existing data were the USGS’s National Water Information System, Ecology’s Environmental Information Management System, and a compilation of several studies by Leidos, a scientific research company. The water-quality parameters of interest included polychlorinated biphenyl (PCB) Aroclors and congeners, phthalates, carcinogenic polycyclic aromatic hydrocarbons (cPAHs), arsenic, copper, and zinc. Results were grouped into the four subwatersheds delineated in Ecology’s hydrology models: Duwamish, Lower Green, Soos, and Upper Green. Results from the Duwamish subwatershed were further sub-divided by the USGS into the Lower Duwamish, containing land adjacent to the Lower Duwamish Waterway Superfund site, and the Upper Duwamish, containing the remaining area of the Duwamish subwatershed. Groundwater quality data in the Lower Duwamish were treated separately because there is known contamination in this area. The availability of water quality data varied by subwatershed as follows: phthalate data was only available within the Duwamish, PCB data was available within the Duwamish and Lower Green, cPAH data was available within the Duwamish, Lower Green, and Soos, and data for arsenic, copper, and zinc were available within all four subwatersheds. More than 99 percent of the available data was within the Duwamish subwatershed, identifying a need for additional monitoring of groundwater quality in the other subwatersheds.

Washington↗

USGS2018

Strategies for effective collaborative manuscript development in interdisciplinary science teams

Science is increasingly being conducted in large, interdisciplinary teams. As team size increases, challenges can arise during manuscript development, where achieving one team goal (e.g., inclusivity) may be in direct conflict with other goals (e.g., efficiency). Here, we present strategies for effective collaborative manuscript development that draw from our experiences in an interdisciplinary science team writing collaborative manuscripts for six years. These strategies are rooted in six guiding principles that were important to our team: to create a transparent, inclusive, and accountable research team that promotes and protects team members who have less power to influence decision‐making while fostering creativity and productivity. To help alleviate the conflicts that can arise in collaborative manuscript development, we present the following strategies: understand your team composition, create an authorship policy and discuss authorship early and often, openly announce manuscript ideas, identify and communicate the type of manuscript and lead author management style, and document and describe authorship contributions. These strategies can help reduce the probability of group conflict, uphold individual and team values, achieve fair authorship practices, and increase science productivity.

Ecosphere↗

USGS2024

Extreme low-frequency waves on the Ofu, American Samoa, reef flat

The southern fringing reef along Ofu, American Samoa, has been a focus of coral research owing to the presence of super-heated pools on the reef flat, where corals thrive in elevated sea temperatures. Here, we present the first documentation of exceptionally large low-frequency (periods > 100 s) waves over this reef flat. During a large, southerly swell event, low-frequency waves on the inner reef flat had mean heights of 0.7 m and periods of 2–4 min and are estimated to have contributed up to 50% of the total water levels. One observed low-frequency wave had a trough-to-peak vertical height of 1.5 m, possibly representing the largest low-frequency wave ever directly observed on a reef flat. These large, low-frequency waves, which were likely amplified by reef resonance, are important factors in coastal hazards such as flooding and erosion and may also be relevant to coral health and resilience.

Ofu, American Samoa↗

USGS2015

Temporal and basin-specific population trends of quagga mussels on soft sediment of a multi-basin reservoir

Invasive quagga (Dreissena bugnesis) and zebra (Dreissena ploymorpha) mussels have rapidly spread throughout North America. Understanding the relationships between environmental variables and quagga mussels during the early stages of invasion will help management strategies and allow researchers to predict patterns of future invasions. Quagga mussels were detected in Lake Mead, NV/AZ in 2007, we monitored early invasion dynamics in 3 basins (Boulder Basin, Las Vegas Bay, Overton Arm) bi-annually from 2008-2011. Mean quagga density increased over time during the first year of monitoring and stabilized for the subsequent two years at the whole-lake scale (8 to 132 individuals·m-2, geometric mean), in Boulder Basin (73 to 875 individuals·m-2), and in Overton Arm(2 to 126 individuals·m-2). In Las Vegas Bay, quagga mussel density was low (9 to 44 individuals·m-2), which was correlated with high sediment metal concentrations and warmer (> 30°C) water temperatures associated with that basin. Carbon content in the sediment increased with depth in Lake Mead and during some sampling periods quagga density was also positively correlated with depth, but more research is required to determine the significance of this interaction. Laboratory growth experiments suggested that food quantity may limit quagga growth in Boulder Basin, indicating an opportunity for population expansion in this basin if primary productivity were to increase, but was not the case in Overton Arm. Overall quagga mussel density in Lake Mead is highly variable and patchy, suggesting that temperature, sediment size, and sediment metal concentrations, and sediment carbon content all contribute to mussel distribution patterns. Quagga mussel density in the soft sediment of Lake Mead expanded during initial colonization, and began to stabilize approximately 3 years after the initial invasion.

Book chapter↗

USGS2018

Quantifying geomorphic and vegetation change at sandbar campsites in response to flow regulation and controlled floods, Grand Canyon National Park, Arizona

Sandbars along the Colorado River in Grand Canyon National Park, USA, are an important recreational resource used as campsites by over 25,000 river runners and hikers annually. The number and size of campsites decreased following the completion of Glen Canyon Dam in 1963 due to reductions of sediment that replenish sandbars and increases in vegetation cover caused by flow regulation. Campsite area continues to decrease despite the use of controlled floods to rebuild sandbars. We quantify the relative magnitude of factors that contribute to changes in campsite size, such as fluvial deposition and erosion, gullying, and vegetation expansion with analysis of four‐band aerial imagery and digital elevation models. Campsite area declined by 37% between 2002 and 2016 (an average of 161 m 2 per site at long‐term monitoring sites). Two drivers contributed to campsite area change: (a) short‐term gains and losses associated with controlled floods and flood‐deposit erosion and (b) long‐term one‐directional loss of campsite area caused by vegetation encroachment. There was more erosion and slope change at sites in critical reaches—sections of river where campsites are infrequent or in high demand—than in noncritical reaches. Vegetation continues to expand at campsites under flow regulation, particularly in noncritical reaches. Although controlled floods have contributed to short‐term increases in sandbar size, long‐term increases in campsite area have not occurred because of sandbar erosion between controlled floods and vegetation expansion. Manual vegetation removal may need to be considered in future management strategies.

Arizona↗

USGS2012

Macondo-1 well oil-derived polycyclic aromatic hydrocarbons in mesozooplankton from the northern Gulf of Mexico

Mesozooplankton (>200 μ m) collected in August and September of 2010 from the northern Gulf of Mexico show evidence of exposure to polycyclic aromatic hydrocarbons (PAHs). Multivariate statistical analysis revealed that distributions of PAHs extracted from mesozooplankton were related to the oil released from the ruptured British Petroleum Macondo-1 (M-1) well associated with the R/V Deepwater Horizon blowout. Mesozooplankton contained 0.03–97.9 ng g −1 of total PAHs and ratios of fluoranthene to fluoranthene + pyrene less than 0.44, indicating a liquid fossil fuel source. The distribution of PAHs isolated from mesozooplankton extracted in this study shows that the 2010 Deepwater Horizon spill may have contributed to contamination in the northern Gulf of Mexico ecosystem.

Gulf of Mexico↗

USGS2019

Insights into pāhoehoe lava emplacement using visible and thermal structure-from-motion photogrammetry

We present the evolution over 3 months of a 2016–2017 pāhoehoe flow at Kīlauea as it changed from a narrow sheet flow into a compound lava field fed by a stable system of tubes. The portion of the flow located on Kīlauea's coastal plain was characterized using helicopter‐based visible and thermal structure‐from‐motion photogrammetry to construct a series of georeferenced digital surface models and thermal maps on eight different days. Results reveal key influences on the emplacement and evolution of such long‐lived pāhoehoe flows. This region of the flow grew by ~12 × 10 6 m 3 with a near‐constant time‐average discharge rate of 1.2–2.7 m 3 /s. The development of two tube systems is captured and shows an initial nascent tube enhanced by a narrow topographic confinement, which later inflated and created a topographic inversion that modulated the emplacement of a second flow lobe with its own tube system. The analysis of breakouts at various stages of the field's life suggests that the evolution of the thermal and morphological properties of the flow surface reflect its maturity. Thermal properties of breakouts were used to expand the empirical relationship of breakout cooling to longer timescales. This study contributes to the long‐term development and validation of more accurate predictive models for pāhoehoe, required during the management of long‐lasting lava flow crises in Hawai'i and elsewhere.

Hawaii↗

USGS2008

Comment on the treatment of residual water content in “A consistent set of parametric models for the two-phase flow of immiscible fluids in the subsurface” by L. Luckner et al.

Luckner et al. [1989] (hereinafter LVN) present a clear summary and generalization of popular formulations used for convenient representation of porous media fluid flow characteristics, including water content ( θ ) related to suction ( h ) and hydraulic conductivity ( K ) related to θ or h. One essential but problematic element in the LVN models is the concept of residual water content ( θ r ; in LVN, θ w , r ). Most studies using θ r determine its value as a fitted parameter and make the assumption that liquid flow processes are negligible at θ values less than θ r . While the LVN paper contributes a valuable discussion of the nature of θ r , it leaves several problems unresolved, including fundamental difficulties in associating a definite physical condition with θ r , practical inadequacies of the models at low θ values, and difficulties in designating a main wetting curve.

Water Resources Research↗

USGS2005

Workgroup report: Drinking-water nitrate and health - Recent findings and research needs

Human alteration of the nitrogen cycle has resulted in steadily accumulating nitrate in our water resources. The U.S. maximum contaminant level and World Health Organization guidelines for nitrate in drinking water were promulgated to protect infants from developing methemoglobinemia, an acute condition. Some scientists have recently suggested that the regulatory limit for nitrate is overly conservative; however, they have not thoroughly considered chronic health outcomes. In August 2004, a symposium on drinking-water nitrate and health was held at the International Society for Environmental Epidemiology meeting to evaluate nitrate exposures and associated health effects in relation to the current regulatory limit. The contribution of drinking-water nitrate toward endogenous formation of N-nitroso compounds was evaluated with a focus toward identifying subpopulations with increased rates of nitrosation. Adverse health effects may be the result of a complex interaction of the amount of nitrate ingested, the concomitant ingestion of nitrosation cofactors and precursors, and specific medical conditions that increase nitrosation. Workshop participants concluded that more experimental studies are needed and that a particularly fruitful approach may be to conduct epidemiologic studies among susceptible subgroups with increased endogenous nitrosation. The few epidemiologic studies that have evaluated intake of nitrosation precursors and/or nitrosation inhibitors have observed elevated risks for colon cancer and neural tube defects associated with drinking-water nitrate concentrations below the regulatory limit. The role of drinking-water nitrate exposure as a risk factor for specific cancers, reproductive outcomes, and other chronic health effects must be studied more thoroughly before changes to the regulatory level for nitrate in drinking water can be considered.

Environmental Health Perspectives↗

USGS2022

Diatoms.org: Supporting taxonomists, connecting communities

Consistent identification of diatoms is a prerequisite for studying their ecology, biogeography, and successful application as environmental indicators. However, taxonomic consistency among observers has been difficult to achieve because taxonomic information is scattered across numerous literature sources, presenting challenges to the diatomist. Firstly, literature is often inaccessible because of cost or its location in journals that are not widely circulated. Secondly, taxonomic revisions of diatoms are taking place faster than floras can be updated. Finally, taxonomic information is often contradictory across literature sources. These issues can be addressed by developing a content creation community dedicated to making taxonomic, ecological, and image-based data freely available for diatom researchers. Diatoms.org represents such a content curation community, providing open, online access to a vast amount of recent and historical information on North American diatom taxonomy and ecology. The content curation community aggregates existing taxonomic information, creates new content, and provides feedback in the form of corrections and notices of literature with nomenclatural changes. The website not only addresses the needs of experienced diatom scientists for consistent identification but is also designed to meet users at their level of expertise, including engaging the lay public in the importance of diatom science. The website now contains over 1000 species pages contributed by over 100 content contributors, from students to established scientists. The project began with the intent to provide accurate information on diatom identification, ecology, and distribution using an approach that incorporates engaging design, user feedback, and advanced data access technology. In retrospect, the project that began as an ‘extended electronic book’ has emerged not only as a means to support taxonomists, but for practitioners to communicate and collaborate, expanding the size of and benefits to the content curation community. In this paper, we outline the development of diatoms.org , document key elements of the project, examine ongoing challenges and consider the unexpected emergent properties, including the value of diatoms.org as a source of data. Ultimately, if the field of diatom taxonomy, ecology, and biodiversity is to be relevant, a new generation of taxonomists needs to be trained and employed using new tools. We propose that diatoms.org is in a key position to serve as a hub of training and continuity for the study of diatom biodiversity and aquatic conditions.

Diatom Research↗

USGS2015

Megathrust earthquakes and sea-level change: A tribute to George Plafker

For numerous scientific disciplines that contribute to the understanding of megathrust earthquakes, 2014 was an anniversary year of two great, >M w 9, earthquakes; fifty years since the March 27 1964 earthquake in Alaska and ten years since the December 26 2004 Aceh-Andaman earthquake and attendant tsunami. 2014 was also the final year of International Geoscience Programme (IGCP) Project 588 “Preparing for Coastal Change”, which was the latest in the 25 year history of IGCP coastal change research.

Quaternary Science Reviews↗