Showing papers by "United States Geological Survey published in 2020"
••
TL;DR: The extent of the trait data compiled in TRY is evaluated and emerging patterns of data coverage and representativeness are analyzed to conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements.
Abstract: Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
882 citations
••
Pacific Northwest National Laboratory1, United States Geological Survey2, Smithsonian Conservation Biology Institute3, Smithsonian Tropical Research Institute4, University of Minnesota5, Joint Global Change Research Institute6, University of Maryland, College Park7, Duke University8, Boston University9, Swiss Federal Institute for Forest, Snow and Landscape Research10, University of California, Berkeley11, Stanford University12, University of Florida13, Lawrence Berkeley National Laboratory14, Northern Arizona University15, Goddard Space Flight Center16, University of Birmingham17, University of Natural Resources and Life Sciences, Vienna18, Technische Universität München19, University of Wisconsin-Madison20, Columbia University21, Oak Ridge National Laboratory22, Los Alamos National Laboratory23
TL;DR: The authors show that shifts in forest dynamics are already occurring, and the emerging pattern is that global forests are tending toward younger stands with faster turnover as old-growth forest with stable dynamics are dwindling.
Abstract: Forest dynamics arise from the interplay of environmental drivers and disturbances with the demographic processes of recruitment, growth, and mortality, subsequently driving biomass and species composition. However, forest disturbances and subsequent recovery are shifting with global changes in climate and land use, altering these dynamics. Changes in environmental drivers, land use, and disturbance regimes are forcing forests toward younger, shorter stands. Rising carbon dioxide, acclimation, adaptation, and migration can influence these impacts. Recent developments in Earth system models support increasingly realistic simulations of vegetation dynamics. In parallel, emerging remote sensing datasets promise qualitatively new and more abundant data on the underlying processes and consequences for vegetation structure. When combined, these advances hold promise for improving the scientific understanding of changes in vegetation demographics and disturbances.
476 citations
••
Conservation International1, Griffith University2, Carleton University3, International Union for Conservation of Nature and Natural Resources4, International Institute of Minnesota5, United States Geological Survey6, UNESCO-IHE Institute for Water Education7, University of Washington8, Cardiff University9, Wildfowl & Wetlands Trust10, Free University of Berlin11
TL;DR: In this paper, the authors present an emergency recovery plan to bend the curve of freshwater biodiversity loss, which includes accelerating implementation of environmental flows; improving water quality; protecting and restoring critical habitats; managing the exploitation of freshwater ecosystem resources, especially species and riverine aggregates; preventing and controlling nonnative species invasions; and safeguarding and restoring river connectivity.
Abstract: Despite their limited spatial extent, freshwater ecosystems host remarkable biodiversity, including one-third of all vertebrate species. This biodiversity is declining dramatically: Globally, wetlands are vanishing three times faster than forests, and freshwater vertebrate populations have fallen more than twice as steeply as terrestrial or marine populations. Threats to freshwater biodiversity are well documented but coordinated action to reverse the decline is lacking. We present an Emergency Recovery Plan to bend the curve of freshwater biodiversity loss. Priority actions include accelerating implementation of environmental flows; improving water quality; protecting and restoring critical habitats; managing the exploitation of freshwater ecosystem resources, especially species and riverine aggregates; preventing and controlling nonnative species invasions; and safeguarding and restoring river connectivity. We recommend adjustments to targets and indicators for the Convention on Biological Diversity and the Sustainable Development Goals and roles for national and international state and nonstate actors.
420 citations
••
University of Alicante1, University of Sydney2, Pablo de Olavide University3, University of Minnesota4, University of New South Wales5, Universidad Mayor6, Spanish National Research Council7, University of California, Merced8, Newcastle University9, University of Western Australia10, University of Melbourne11, Fujian Normal University12, National Taiwan University13, University of Innsbruck14, University of Chile15, United States Geological Survey16, University of Nevada, Reno17, Colorado State University18, Arizona State University19, Virginia Tech20
TL;DR: Evidence is provided that soil biodiversity (bacteria, fungi, protists and invertebrates) is significantly and positively associated with multiple ecosystem functions including nutrient cycling, decomposition, plant production, and reduced potential for pathogenicity and belowground biological warfare.
Abstract: The role of soil biodiversity in regulating multiple ecosystem functions is poorly understood, limiting our ability to predict how soil biodiversity loss might affect human wellbeing and ecosystem sustainability. Here, combining a global observational study with an experimental microcosm study, we provide evidence that soil biodiversity (bacteria, fungi, protists and invertebrates) is significantly and positively associated with multiple ecosystem functions. These functions include nutrient cycling, decomposition, plant production, and reduced potential for pathogenicity and belowground biological warfare. Our findings also reveal the context dependency of such relationships and the importance of the connectedness, biodiversity and nature of the globally distributed dominant phylotypes within the soil network in maintaining multiple functions. Moreover, our results suggest that the positive association between plant diversity and multifunctionality across biomes is indirectly driven by soil biodiversity. Together, our results provide insights into the importance of soil biodiversity for maintaining soil functionality locally and across biomes, as well as providing strong support for the inclusion of soil biodiversity in conservation and management programmes.
405 citations
••
University of Guelph1, Institute of Arctic and Alpine Research2, Brigham Young University3, United States Geological Survey4, University of Alaska Fairbanks5, University of Alberta6, Northern Arizona University7, Alfred Wegener Institute for Polar and Marine Research8, University of Potsdam9, Stockholm University10, Lawrence Berkeley National Laboratory11, National Center for Atmospheric Research12
TL;DR: In this article, the authors synthesize the best available information and develop inventory models to simulate abrupt thaw impacts on permafrost carbon balance, and they conclude that models considering only gradual thaw are substantially underestimating carbon emissions.
Abstract: The permafrost zone is expected to be a substantial carbon source to the atmosphere, yet large-scale models currently only simulate gradual changes in seasonally thawed soil. Abrupt thaw will probably occur in <20% of the permafrost zone but could affect half of permafrost carbon through collapsing ground, rapid erosion and landslides. Here, we synthesize the best available information and develop inventory models to simulate abrupt thaw impacts on permafrost carbon balance. Emissions across 2.5 million km2 of abrupt thaw could provide a similar climate feedback as gradual thaw emissions from the entire 18 million km2 permafrost region under the warming projection of Representative Concentration Pathway 8.5. While models forecast that gradual thaw may lead to net ecosystem carbon uptake under projections of Representative Concentration Pathway 4.5, abrupt thaw emissions are likely to offset this potential carbon sink. Active hillslope erosional features will occupy 3% of abrupt thaw terrain by 2300 but emit one-third of abrupt thaw carbon losses. Thaw lakes and wetlands are methane hot spots but their carbon release is partially offset by slowly regrowing vegetation. After considering abrupt thaw stabilization, lake drainage and soil carbon uptake by vegetation regrowth, we conclude that models considering only gradual permafrost thaw are substantially underestimating carbon emissions from thawing permafrost. Analyses of inventory models under two climate change projection scenarios suggest that carbon emissions from abrupt thaw of permafrost through ground collapse, erosion and landslides could contribute significantly to the overall permafrost carbon balance.
399 citations
••
TL;DR: This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade.
Abstract: Gas hydrates have received considerable attention due to their important role in flow assurance for the oil and gas industry, their extensive natural occurrence on Earth and extraterrestrial planets, and their significant applications in sustainable technologies including but not limited to gas and energy storage, gas separation, and water desalination Given not only their inherent structural flexibility depending on the type of guest gas molecules and formation conditions, but also the synthetic effects of a wide range of chemical additives on their properties, these variabilities could be exploited to optimise the role of gas hydrates This includes increasing their industrial applications, understanding and utilising their role in Nature, identifying potential methods for safely extracting natural gases stored in naturally occurring hydrates within the Earth, and for developing green technologies This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade Challenges, limitations, and future perspectives of each field are briefly discussed The overall objective of this review is to provide readers with an extensive overview of gas hydrates that we hope will stimulate further work on this riveting field
349 citations
••
TL;DR: The 2016 National Land Cover Database (NLCD) product suite as discussed by the authors provides important new information on land change patterns across CONUS from 2001 to 2016, including land cover, urban imperviousness, and tree, shrub, herbaceous and bare ground fractional percentages.
Abstract: The 2016 National Land Cover Database (NLCD) product suite (available on www.mrlc.gov ), includes Landsat-based, 30 m resolution products over the conterminous (CONUS) United States (U.S.) for land cover, urban imperviousness, and tree, shrub, herbaceous and bare ground fractional percentages. The release of NLCD 2016 provides important new information on land change patterns across CONUS from 2001 to 2016. For land cover, seven epochs were concurrently generated for years 2001, 2004, 2006, 2008, 2011, 2013, and 2016. Products reveal that land cover change is significant across most land cover classes and time periods. The land cover product was validated using existing reference data from the legacy NLCD 2011 accuracy assessment, applied to the 2011 epoch of the NLCD 2016 product line. The legacy and new NLCD 2011 overall accuracies were 82% and 83%, respectively, (standard error (SE) was 0.5%), demonstrating a small but significant increase in overall accuracy. Between 2001 and 2016, the CONUS landscape experienced significant change, with almost 8% of the landscape having experienced a land cover change at least once during this period. Nearly 50% of that change involves forest, driven by change agents of harvest, fire, disease and pests that resulted in an overall forest decline, including increasing fragmentation and loss of interior forest. Agricultural change represented 15.9% of the change, with total agricultural spatial extent showing only a slight increase of 4778 km2, however there was a substantial decline (7.94%) in pasture/hay during this time, transitioning mostly to cultivated crop. Water and wetland change comprised 15.2% of change and represent highly dynamic land cover classes from epoch to epoch, heavily influenced by precipitation. Grass and shrub change comprise 14.5% of the total change, with most change resulting from fire. Developed change was the most persistent and permanent land change increase adding almost 29,000 km2 over 15 years (5.6% of total CONUS change), with southern states exhibiting expansion much faster than most of the northern states. Temporal rates of developed change increased in 2001–2006 at twice the rate of 2011–2016, reflecting a slowdown in CONUS economic activity. Future NLCD plans include increasing monitoring frequency, reducing latency time between satellite imaging and product delivery, improving accuracy and expanding the variety of products available in an integrated database.
332 citations
••
Stanford University1, Stockholm University2, Texas A&M University3, University of Exeter4, United States Geological Survey5, University of California, Los Angeles6, University of Jyväskylä7, University of Alberta8, University of Toronto9, Umeå University10, University of New Hampshire11, University of Colorado Boulder12, University of Guelph13, Université de Montréal14, Northeast Normal University15, Lehigh University16
TL;DR: This study compiles over 7,000 field observations to present a data-driven map of northern peatlands and their carbon and nitrogen stocks, and uses machine-learning techniques with extensive peat core data to create observation-based maps ofNorthern peatland C and N stocks and to assess their response to warming and permafrost thaw.
Abstract: Northern peatlands have accumulated large stocks of organic carbon (C) and nitrogen (N), but their spatial distribution and vulnerability to climate warming remain uncertain. Here, we used machine-learning techniques with extensive peat core data (n > 7,000) to create observation-based maps of northern peatland C and N stocks, and to assess their response to warming and permafrost thaw. We estimate that northern peatlands cover 3.7 ± 0.5 million km2 and store 415 ± 150 Pg C and 10 ± 7 Pg N. Nearly half of the peatland area and peat C stocks are permafrost affected. Using modeled global warming stabilization scenarios (from 1.5 to 6 °C warming), we project that the current sink of atmospheric C (0.10 ± 0.02 Pg C⋅y-1) in northern peatlands will shift to a C source as 0.8 to 1.9 million km2 of permafrost-affected peatlands thaw. The projected thaw would cause peatland greenhouse gas emissions equal to ∼1% of anthropogenic radiative forcing in this century. The main forcing is from methane emissions (0.7 to 3 Pg cumulative CH4-C) with smaller carbon dioxide forcing (1 to 2 Pg CO2-C) and minor nitrous oxide losses. We project that initial CO2-C losses reverse after ∼200 y, as warming strengthens peatland C-sinks. We project substantial, but highly uncertain, additional losses of peat into fluvial systems of 10 to 30 Pg C and 0.4 to 0.9 Pg N. The combined gaseous and fluvial peatland C loss estimated here adds 30 to 50% onto previous estimates of permafrost-thaw C losses, with southern permafrost regions being the most vulnerable.
294 citations
••
TL;DR: In this paper, a bathymetric sill in Sherard Osborn Fjord, northwest Greenland shields Ryder Glacier from melting by warm Atlantic water found at the bottom of the fjord.
Abstract: The processes controlling advance and retreat of outlet glaciers in fjords draining the Greenland Ice Sheet remain poorly known, undermining assessments of their dynamics and associated sea-level rise in a warming climate. Mass loss of the Greenland Ice Sheet has increased six-fold over the last four decades, with discharge and melt from outlet glaciers comprising key components of this loss. Here we acquired oceanographic data and multibeam bathymetry in the previously uncharted Sherard Osborn Fjord in northwest Greenland where Ryder Glacier drains into the Arctic Ocean. Our data show that warmer subsurface water of Atlantic origin enters the fjord, but Ryder Glacier’s floating tongue at its present location is partly protected from the inflow by a bathymetric sill located in the innermost fjord. This reduces under-ice melting of the glacier, providing insight into Ryder Glacier’s dynamics and its vulnerability to inflow of Atlantic warmer water. A bathymetric sill in Sherard Osborn Fjord, northwest Greenland shields Ryder Glacier from melting by warm Atlantic water found at the bottom of the fjord, according to high-resolution bathymetric mapping and oceanographic data.
288 citations
••
University of Colorado Boulder1, United States Forest Service2, Colorado State University3, University of Montana4, University of New Mexico5, Natural Resources Canada6, Kent State University7, University of California, Berkeley8, University of Arizona9, Northern Arizona University10, University of Washington11, University of Vermont12, United States Geological Survey13, University of Wisconsin-Madison14
TL;DR: This article synthesizes a growing body of evidence of fire-driven conversion and understanding of its causes across western North America and proposes key themes for applied research coproduced by scientists and managers to support decision-making in an era when the prefire forest may not return.
Abstract: Changing disturbance regimes and climate can overcome forest ecosystem resilience. Following high-severity fire, forest recovery may be compromised by lack of tree seed sources, warmer and drier postfire climate, or short-interval reburning. A potential outcome of the loss of resilience is the conversion of the prefire forest to a different forest type or nonforest vegetation. Conversion implies major, extensive, and enduring changes in dominant species, life forms, or functions, with impacts on ecosystem services. In the present article, we synthesize a growing body of evidence of fire-driven conversion and our understanding of its causes across western North America. We assess our capacity to predict conversion and highlight important uncertainties. Increasing forest vulnerability to changing fire activity and climate compels shifts in management approaches, and we propose key themes for applied research coproduced by scientists and managers to support decision-making in an era when the prefire forest may not return.
268 citations
••
TL;DR: The GFDL Earth System Model 4.1 (ESM4.1) as mentioned in this paper was developed as part of its fourth-generation coupled model development activities with model results contributed publicly to the sixth phase of the Coupled Model Intercomparison Project.
Abstract: We describe the baseline coupled model configuration and simulation characteristics of GFDL's Earth System Model Version 4.1 (ESM4.1), which builds on component and coupled model developments at GFDL over 2013–2018 for coupled carbon‐chemistry‐climate simulation contributing to the sixth phase of the Coupled Model Intercomparison Project. In contrast with GFDL's CM4.0 development effort that focuses on ocean resolution for physical climate, ESM4.1 focuses on comprehensiveness of Earth system interactions. ESM4.1 features doubled horizontal resolution of both atmosphere (2° to 1°) and ocean (1° to 0.5°) relative to GFDL's previous‐generation coupled ESM2‐carbon and CM3‐chemistry models. ESM4.1 brings together key representational advances in CM4.0 dynamics and physics along with those in aerosols and their precursor emissions, land ecosystem vegetation and canopy competition, and multiday fire; ocean ecological and biogeochemical interactions, comprehensive land‐atmosphere‐ocean cycling of CO2, dust and iron, and interactive ocean‐atmosphere nitrogen cycling are described in detail across this volume of JAMES and presented here in terms of the overall coupling and resulting fidelity. ESM4.1 provides much improved fidelity in CO2 and chemistry over ESM2 and CM3, captures most of CM4.0's baseline simulations characteristics, and notably improves on CM4.0 in (1) Southern Ocean mode and intermediate water ventilation, (2) Southern Ocean aerosols, and (3) reduced spurious ocean heat uptake. ESM4.1 has reduced transient and equilibrium climate sensitivity compared to CM4.0. Fidelity concerns include (1) moderate degradation in sea surface temperature biases, (2) degradation in aerosols in some regions, and (3) strong centennial scale climate modulation by Southern Ocean convection. Plain Language Summary GFDL has developed a coupled chemistry‐carbon‐climate Earth System Model (ESM4.1) as part of its fourth‐generation coupled model development activities with model results contributed publicly to the sixth phase of the Coupled Model Intercomparison Project. With similar computational expense as GFDL's first coupled model CM4.0, ESM4.1 focuses on chemistry and ecosystem comprehensiveness rather than the ocean resolution‐focus of CM4.0. With fidelity near to that of CM4.0, ESM4.1 features much improved representation of climate mean patterns and variability from previous GFDL ESMs as well as comprehensive couplings for chemistry, carbon, and dust.
••
United States Geological Survey1, National Oceanic and Atmospheric Administration2, Woods Hole Oceanographic Institution3, National Marine Fisheries Service4, University of Washington5, United States Department of the Interior6, Gulf of Maine Research Institute7, Silver Spring Networks8, University of Maryland, College Park9, United States Forest Service10, Michigan State University11
TL;DR: It is found that species are responding to climate change through changes in morphology and behavior, phenology, and geographic range shifts, and these changes are mediated by plastic and evolutionary responses.
••
Morton Arboretum1, Cardiff University2, University of Idaho3, University of Toulouse4, Environmental Protection Agency5, University of Freiburg6, University of British Columbia7, City College of New York8, University of Pretoria9, Flinders University10, National Autonomous University of Mexico11, Colorado State University12, University of Sydney13, United States Geological Survey14, University of São Paulo15, Massey University16, Katholieke Universiteit Leuven17, Research Institute for Nature and Forest18, Natural History Museum19, Tarbiat Modares University20, Scottish Natural Heritage21, University of Edinburgh22, State University of Campinas23, National Centre for Biological Sciences24, University of Yaoundé I25, Stockholm University26
TL;DR: The 196 parties to the Convention on Biological Diversity (CBD) will soon agree to a post-2020 global framework for conserving the three elements of biodiversity (genetic, species, and ecosystem diversity) while ensuring sustainable development and benefit sharing.
••
01 Jul 2020
TL;DR: In this article, the USGS's Ecosystems Mission Area, Invasive Species Program, intramural research program of the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center and an Ignite Grant #IGN07171717 from Innovate BC.
Abstract: This project was funded in part by USGS's Ecosystems Mission Area, Invasive Species Program, the intramural research program of the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center and an Ignite Grant #IGN071717 from Innovate BC. We thank Nick Akins, Lauren Bergman, Leah Botkin, Erica Mize, Nikolas Grueneis, Xin Guan, Danyang (Sandy) Shen, Nathan Thompson, Kyle Von Ruden, Alvi Wadud, and Kristyne Wozney for technical support.
••
Imperial College London1, University of Exeter2, Broad Institute3, United States Geological Survey4, University of California, Riverside5, University of Kiel6, Max Planck Society7, University of Toronto8, Manchester Academic Health Science Centre9, University of Wisconsin-Madison10, University of British Columbia11, McGill University12, University of California, Berkeley13, McMaster University14, Duke University15, Johns Hopkins University16
TL;DR: P poignant examples of emerging fungal threats in each of three areas: human health, wildlife biodiversity, and food security are focused on.
Abstract: The fungal kingdom includes at least 6 million eukaryotic species and is remarkable with respect to its profound impact on global health, biodiversity, ecology, agriculture, manufacturing, and biomedical research. Approximately 625 fungal species have been reported to infect vertebrates, 200 of which can be human associated, either as commensals and members of our microbiome or as pathogens that cause infectious diseases. These organisms pose a growing threat to human health with the global increase in the incidence of invasive fungal infections, prevalence of fungal allergy, and the evolution of fungal pathogens resistant to some or all current classes of antifungals. More broadly, there has been an unprecedented and worldwide emergence of fungal pathogens affecting animal and plant biodiversity. Approximately 8,000 species of fungi and Oomycetes are associated with plant disease. Indeed, across agriculture, such fungal diseases of plants include new devastating epidemics of trees and jeopardize food security worldwide by causing epidemics in staple and commodity crops that feed billions. Further, ingestion of mycotoxins contributes to ill health and causes cancer. Coordinated international research efforts, enhanced technology translation, and greater policy outreach by scientists are needed to more fully understand the biology and drivers that underlie the emergence of fungal diseases and to mitigate against their impacts. Here, we focus on poignant examples of emerging fungal threats in each of three areas: human health, wildlife biodiversity, and food security.
••
Royal Observatory of Belgium1, Imperial College London2, University of Auckland3, Royal Holloway, University of London4, National Autonomous University of Mexico5, Swiss Seismological Service6, University of Helsinki7, United States Geological Survey8, Central Institution for Meteorology and Geodynamics9, University of Costa Rica10, Royal Netherlands Meteorological Institute11, University of Potsdam12, Kandilli Observatory and Earthquake Research Institute13, National Institute of Geophysics and Volcanology14, University of Catania15, University of Cologne16, University of Savoy17, King's College, Aberdeen18, Dublin Institute for Advanced Studies19, Delft University of Technology20, Spanish National Research Council21, Institute for Geosciences and Natural Resources22, Mediterranean University23, Norwegian Geotechnical Institute24, University of Alaska Fairbanks25, University of Strasbourg26, University of Lausanne27, University of Bristol28, Princeton University29, University of Tehran30, Boston College31, California Institute of Technology32, Stanford University33, Search for extraterrestrial intelligence34, University of British Columbia35, Ludwig Maximilian University of Munich36, Australian National University37, McGill University38, University of Maine39, University of California, Riverside40, University of Chile41, University of Oxford42, BBN Technologies43, Institut de Physique du Globe de Paris44, Victoria University of Wellington45, University of Patras46, University of Bergen47, University of California, Berkeley48, Institut d'Estudis Catalans49, University of Michigan50, University of California, Santa Barbara51
TL;DR: The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record and suggests that seismology provides an absolute, real-time estimate of human activities.
Abstract: Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the coronavirus disease 2019 (COVID-19) pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. Although the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth. This quiet period provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise. A strong correlation between seismic noise and independent measurements of human mobility suggests that seismology provides an absolute, real-time estimate of human activities.
••
TL;DR: A Monte Carlo simulation with a radiation-aware hydrologic model resolves the longstanding, wide disparity in sensitivity estimates and reveals the controlling physical processes behind increased evapotranspiration in the Colorado River.
Abstract: The sensitivity of river discharge to climate-system warming is highly uncertain, and the processes that govern river discharge are poorly understood, which impedes climate-change adaptation. A prominent exemplar is the Colorado River, where meteorological drought and warming are shrinking a water resource that supports more than 1 trillion dollars of economic activity per year. A Monte Carlo simulation with a radiation-aware hydrologic model resolves the longstanding, wide disparity in sensitivity estimates and reveals the controlling physical processes. We estimate that annual mean discharge has been decreasing by 9.3% per degree Celsius of warming because of increased evapotranspiration, mainly driven by snow loss and a consequent decrease in reflection of solar radiation. Projected precipitation increases likely will not suffice to fully counter the robust, thermodynamically induced drying. Thus, an increasing risk of severe water shortages is expected.
••
••
Tsinghua University1, University of California, Davis2, Iowa State University3, Chinese Academy of Sciences4, Nanjing University5, Central South University Forestry and Technology6, Tongji University7, Wuhan University8, Jilin University9, Peking University10, Sun Yat-sen University11, Southwest University12, Hong Kong Polytechnic University13, Yanbian University14, Jiangxi Normal University15, Chongqing Normal University16, Zhejiang University17, Henan University18, Texas Southern University19, Huazhong University of Science and Technology20, University of Hong Kong21, Guangzhou University22, Shandong University of Science and Technology23, National Cheng Kung University24, Hohai University25, Lanzhou University26, University of Kentucky27, Fujian Normal University28, Central China Normal University29, Hong Kong Baptist University30, United States Geological Survey31
TL;DR: For example, in this article, the authors present a set of urban land use maps at the national and global scales that are derived from the same or consistent data sources with similar or compatible classification systems and mapping methods.
Abstract: Land use reflects human activities on land. Urban land use is the highest level human alteration on Earth, and it is rapidly changing due to population increase and urbanization. Urban areas have widespread effects on local hydrology, climate, biodiversity, and food production. However, maps, that contain knowledge on the distribution, pattern and composition of various land use types in urban areas, are limited to city level. The mapping standard on data sources, methods, land use classification schemes varies from city to city, due to differences in financial input and skills of mapping personnel. To address various national and global environmental challenges caused by urbanization, it is important to have urban land uses at the national and global scales that are derived from the same or consistent data sources with the same or compatible classification systems and mapping methods. This is because, only with urban land use maps produced with similar criteria, consistent environmental policies can be made, and action efforts can be compared and assessed for large scale environmental administration. However, despite of the fact that a number of urban-extent maps exist at global scales [3,4], more detailed urban land use maps do not exist at the same scale. Even at big country or regional levels such as for the United States, China and European Union, consistent land use mapping efforts are rare.
••
••
TL;DR: In this paper, a detailed investigation of the mineralogical and morphological properties of geological units within Jezero crater was conducted to better constrain the origin of carbonates in the basin and their timing relative to fluvio-lacustrine activity.
••
United States Geological Survey1, University of Washington2, United States Fish and Wildlife Service3, Humboldt State University4, National Park Service5, National Marine Fisheries Service6, Moss Landing Marine Laboratories7, National Oceanic and Atmospheric Administration8, Point Blue Conservation Science9
TL;DR: It is hypothesized that these bottom-up and top-down forces created an “ectothermic vise” on forage species leading to their system-wide scarcity and resulting in mass mortality of murres and many other fish, bird and mammal species in the region during 2014–2017.
Abstract: About 62,000 dead or dying common murres (Uria aalge), the trophically dominant fish-eating seabird of the North Pacific, washed ashore between summer 2015 and spring 2016 on beaches from California to Alaska. Most birds were severely emaciated and, so far, no evidence for anything other than starvation was found to explain this mass mortality. Three-quarters of murres were found in the Gulf of Alaska and the remainder along the West Coast. Studies show that only a fraction of birds that die at sea typically wash ashore, and we estimate that total mortality approached 1 million birds. About two-thirds of murres killed were adults, a substantial blow to breeding populations. Additionally, 22 complete reproductive failures were observed at multiple colonies region-wide during (2015) and after (2016-2017) the mass mortality event. Die-offs and breeding failures occur sporadically in murres, but the magnitude, duration and spatial extent of this die-off, associated with multi-colony and multi-year reproductive failures, is unprecedented and astonishing. These events co-occurred with the most powerful marine heatwave on record that persisted through 2014-2016 and created an enormous volume of ocean water (the "Blob") from California to Alaska with temperatures that exceeded average by 2-3 standard deviations. Other studies indicate that this prolonged heatwave reduced phytoplankton biomass and restructured zooplankton communities in favor of lower-calorie species, while it simultaneously increased metabolically driven food demands of ectothermic forage fish. In response, forage fish quality and quantity diminished. Similarly, large ectothermic groundfish were thought to have increased their demand for forage fish, resulting in greater top-predator demands for diminished forage fish resources. We hypothesize that these bottom-up and top-down forces created an "ectothermic vise" on forage species leading to their system-wide scarcity and resulting in mass mortality of murres and many other fish, bird and mammal species in the region during 2014-2017.
••
TL;DR: In this paper, the authors presented an algorithm that exploits all available Sentinel-1 SAR images in combination with historical Landsat and other auxiliary data sources hosted on the Google Earth Engine (GEE) to rapidly map surface inundation during flood events.
••
TL;DR: Due to the heavy use of neonicotinoid insecticides and potential for cumulative chronic exposure, these insecticides represent novel risks and necessitate further study to fully understand their risks to humans.
Abstract: Neonicotinoid insecticides are widely used in both urban and agricultural settings around the world. Historically, neonicotinoid insecticides have been viewed as ideal replacements for more toxic compounds, like organophosphates, due in part to their perceived limited potential to affect the environment and human health. This critical review investigates the environmental fate and toxicity of neonicotinoids and their metabolites and the potential risks associated with exposure. Neonicotinoids are found to be ubiquitous in the environment, drinking water, and food, with low-level exposure commonly documented below acceptable daily intake standards. Available toxicological data from animal studies indicate possible genotoxicity, cytotoxicity, impaired immune function, and reduced growth and reproductive success at low concentrations, while limited data from ecological or cross-sectional epidemiological studies have identified acute and chronic health effects ranging from acute respiratory, cardiovascular, and neurological symptoms to oxidative genetic damage and birth defects. Due to the heavy use of neonicotinoids and potential for cumulative chronic exposure, these insecticides represent novel risks and necessitate further study to fully understand their risks to humans.
••
TL;DR: Hierarchical clustering identified the two main pathways of antibiotic transfer in various environmental compartments, which are from animal wastewater/WWTP effluent to surface water/sediment and from animal manure/ WWTP sludge to soil/groundwater.
••
TL;DR: Initial performance testing of OLI-2 and TIRS-2 indicate that the instruments are of excellent quality and expected to match or improve on Landsat 8 data quality.
••
American Museum of Natural History1, University of Southern California2, Earlham College3, University of Western Australia4, United States Geological Survey5, University of Florida6, University of Georgia7, Hofstra University8, University of Arizona9, Charles Darwin University10, Wildlife Conservation Society11, University of California, Los Angeles12, University of Canberra13, Hainan Normal University14, University of the Western Cape15, University of Hawaii at Hilo16, Hanoi University of Science17, Edinboro University of Pennsylvania18, Rivers State University of Science and Technology19, University of Antioquia20, Ohio University21, National Oceanic and Atmospheric Administration22, University of Sydney23, La Trobe University24, National Institute of Amazonian Research25
TL;DR: Survival threats to turtles and tortoises are examined and the interventions that will be needed to prevent widespread extinction in this group in coming decades are discussed.
••
24 Feb 2020
TL;DR: In this paper, the chemical processes that control the concentration of critical metals in deep-ocean polymetallic nodules, discuss the mining and metallurgical techniques required, and highlight the opportunities and potential risks that are presented by this new industry.
Abstract: Deep-ocean polymetallic nodules form on or just below the vast, sediment-covered, abyssal plains of the global ocean. Polymetallic nodules primarily consist of precipitated iron oxyhydroxides and manganese oxides, onto which metals such as nickel, cobalt, copper, titanium and rare earth elements sorb. The enormous tonnage of nodules on the seabed, and the immense quantities of critical metals that they contain, have made them a target for future mining operations. Mining of polymetallic nodules has been spurred by the need for critical metals to support growing populations, urbanization, high-technology applications and the development of a green-energy economy. Nevertheless, an improved understanding of the affected ecosystems and their connectivity, as well as the environmental impacts of deep-ocean mining, is required before operations begin. Opportunities exist, however, to ensure that this new industry applies adaptive management to continually refine operations with the goal of environmental protection and invests in the development of green technologies for extractive metallurgy and mining. In this Review, we explore the chemical processes that control the concentration of critical metals in deep-ocean polymetallic nodules, discuss the mining and metallurgical techniques required, and highlight the opportunities and potential risks that are presented by this new industry. Deep-ocean polymetallic nodules contain an enormous tonnage of critical metals, which are vital natural resources for green-energy technologies and vehicles. This Review highlights the formation processes of these nodules and outlines the advantages and disadvantages for this developing industry moving forward.
••
Chesapeake Energy1, Ames Research Center2, Planetary Science Institute3, Goddard Space Flight Center4, Carnegie Institution for Science5, Jacobs Engineering Group6, California Institute of Technology7, Lunar and Planetary Institute8, University of Arizona9, Search for extraterrestrial intelligence10, University of Leicester11, United States Geological Survey12, University of Tennessee13, University of Guelph14, University of New Mexico15, Johns Hopkins University Applied Physics Laboratory16, Rice University17, Indiana University18, Arizona State University19, Los Alamos National Laboratory20
TL;DR: The Curiosity rover was sent to Gale crater to study a sequence of ∼3.5 Ga old sedimentary rocks that, based on orbital visible and near-to short-wave infrared reflectance spectra, contain secondary minerals that suggest deposition and/or alteration in liquid water.
Abstract: The Mars Science Laboratory Curiosity rover arrived at Mars in August 2012 with a primary goal of characterizing the habitability of ancient and modern environments. Curiosity was sent to Gale crater to study a sequence of ∼3.5 Ga old sedimentary rocks that, based on orbital visible and near- to short-wave infrared reflectance spectra, contain secondary minerals that suggest deposition and/or alteration in liquid water. The sedimentary sequence in the lower slopes of Mount Sharp in Gale crater preserves a dramatic shift on early Mars from a relatively warm and wet climate to a cold and dry climate, based on a transition from smectite-bearing strata to sulfate-bearing strata. The rover is equipped with instruments to examine the sedimentology and identify compositional changes in the stratigraphy. The Chemistry and Mineralogy (CheMin) instrument is one of two internal laboratories on Curiosity and includes a transmission X-ray diffractometer (XRD) and X-ray fluorescence (XRF) spectrometer. CheMin measures loose sediment samples scooped from the surface and drilled rock powders, and the XRD provides quantitative mineralogy to a detection limit of ∼1 wt.% for crystalline phases. Curiosity has traversed >20 km since landing and has primarily been exploring an ancient lake environment fed by streams and groundwater. Of the 19 drilled rock samples analyzed by CheMin as of sol 2300 (January 2019), 15 are from fluvio-lacustrine deposits that comprise the Bradbury and Murray formations. Most of these samples were drilled from units that did not have a clear mineralogical signature from orbit. Results from CheMin demonstrate an astounding diversity in the mineralogy of these rocks that signifies geochemical variations in source rocks, transportation mechanisms, and depositional and diagenetic fluids. Most detrital igneous minerals are basaltic, but the discovery in a few samples of abundant silicate minerals that usually crystallize from evolved magmas on Earth remains enigmatic. Trioctahedral smectite and magnetite at the base of the section may have formed from low-salinity pore waters with a circumneutral pH in lake sediments. A transition to dioctahedral smectite, hematite, and Ca-sulfate going up section suggests a change to more saline and oxidative aqueous conditions in the lake waters themselves and/or in diagenetic fluids. Perhaps one of the biggest mysteries revealed by CheMin is the high abundance of X-ray amorphous materials (15–73 wt.%) in all samples drilled or scooped to date. CheMin has analyzed three modern eolian sands, which have helped constrain sediment transport and mineral segregation across the active Bagnold Dune Field. Ancient eolian sandstones drilled from the Stimson formation differ from modern eolian sands in that they contain abundant magnetite but no olivine, suggesting that diagenetic processes led to the alteration of olivine to release Fe(II) and precipitate magnetite. Fracture-associated halos in the Stimson and the Murray formations are evidence for complex aqueous processes long after the streams and lakes vanished from Gale crater. The sedimentology and composition of the rocks analyzed by Curiosity demonstrate that habitable environments persisted intermittently on the surface or in the subsurface of Gale crater for perhaps more than a billion years.
••
United States Geological Survey1, University of California, Riverside2, Reed College3, University of California, Berkeley4, Johns Hopkins University5, United States Environmental Protection Agency6, Oregon State University7, United States Department of Agriculture8, University of Washington9, United States Forest Service10, University of Alberta11, University of California, Davis12
TL;DR: This Special Issue proposes considering refugia in the context of a multifaceted, long-term, network-based approach, as temporal and spatial gradients of ecological persistence that can act as “slow lanes” rather than areas of stasis.
Abstract: Climate-change adaptation focuses on conducting and translating research to minimize the dire impacts of anthropogenic climate change, including threats to biodiversity and human welfare. One adaptation strategy is to focus conservation on climate-change refugia (that is, areas relatively buffered from contemporary climate change over time that enable persistence of valued physical, ecological, and sociocultural resources). In this Special Issue, recent methodological and conceptual advances in refugia science will be highlighted. Advances in this emerging subdiscipline are improving scientific understanding and conservation in the face of climate change by considering scale and ecosystem dynamics, and looking beyond climate exposure to sensitivity and adaptive capacity. We propose considering refugia in the context of a multifaceted, long-term, network-based approach, as temporal and spatial gradients of ecological persistence that can act as "slow lanes" rather than areas of stasis. After years of discussion confined primarily to the scientific literature, researchers and resource managers are now working together to put refugia conservation into practice.