Showing papers by "United States Geological Survey published in 2021"
Yale University1, Southern Cross University2, University of Liège3, United States Geological Survey4, St. Olaf College5, Cornell University6, Beijing Normal University7, Sichuan University8, Chinese Academy of Sciences9, University of California, Santa Barbara10, King Abdullah University of Science and Technology11, Aarhus University12, Texas A&M University13, University of Alberta14, Goddard Space Flight Center15, École Polytechnique Fédérale de Lausanne16
TL;DR: In this article, the authors present a metadata analysis of methane fluxes from all major natural, impacted and human-made aquatic ecosystems and conclude that aquatic emissions will probably increase due to urbanization, eutrophication and positive climate feedbacks.
Abstract: Atmospheric methane is a potent greenhouse gas that plays a major role in controlling the Earth’s climate The causes of the renewed increase of methane concentration since 2007 are uncertain given the multiple sources and complex biogeochemistry Here, we present a metadata analysis of methane fluxes from all major natural, impacted and human-made aquatic ecosystems Our revised bottom-up global aquatic methane emissions combine diffusive, ebullitive and/or plant-mediated fluxes from 15 aquatic ecosystems We emphasize the high variability of methane fluxes within and between aquatic ecosystems and a positively skewed distribution of empirical data, making global estimates sensitive to statistical assumptions and sampling design We find aquatic ecosystems contribute (median) 41% or (mean) 53% of total global methane emissions from anthropogenic and natural sources We show that methane emissions increase from natural to impacted aquatic ecosystems and from coastal to freshwater ecosystems We argue that aquatic emissions will probably increase due to urbanization, eutrophication and positive climate feedbacks and suggest changes in land-use management as potential mitigation strategies to reduce aquatic methane emissions Methane emissions from aquatic systems contribute approximately half of global methane emissions, according to meta-analysis of natural, impacted and human-made aquatic ecosystems and indicating potential mitigation strategies to reduce emissions
239 citations
Oak Ridge National Laboratory1, University of New South Wales2, Ludwig Maximilian University of Munich3, University of Arizona4, Stanford University5, Scripps Institution of Oceanography6, Smithsonian Environmental Research Center7, University of Sydney8, Max Planck Society9, Smithsonian Conservation Biology Institute10, Smithsonian Tropical Research Institute11, Seconda Università degli Studi di Napoli12, University of Leeds13, Swiss Federal Institute for Forest, Snow and Landscape Research14, Aix-Marseille University15, University of California, Santa Barbara16, Commonwealth Scientific and Industrial Research Organisation17, Université Paris-Saclay18, Australian National University19, National University of Singapore20, ETH Zurich21, California Institute of Technology22, Imperial College London23, Northern Arizona University24, Oeschger Centre for Climate Change Research25, University of California, Berkeley26, Lawrence Berkeley National Laboratory27, University of Basel28, Auckland University of Technology29, Indiana University30, University of Oxford31, Spanish National Research Council32, Umeå University33, University of Exeter34, Lawrence Livermore National Laboratory35, University of California, Irvine36, United States Geological Survey37, State University of New York College of Environmental Science and Forestry38, Rutgers University39, Wageningen University and Research Centre40
TL;DR: A range of evidence supports a positive terrestrial carbon sink in response to iCO2, albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.
Abstract: Atmospheric carbon dioxide concentration ([CO2 ]) is increasing, which increases leaf-scale photosynthesis and intrinsic water-use efficiency. These direct responses have the potential to increase plant growth, vegetation biomass, and soil organic matter; transferring carbon from the atmosphere into terrestrial ecosystems (a carbon sink). A substantial global terrestrial carbon sink would slow the rate of [CO2 ] increase and thus climate change. However, ecosystem CO2 responses are complex or confounded by concurrent changes in multiple agents of global change and evidence for a [CO2 ]-driven terrestrial carbon sink can appear contradictory. Here we synthesize theory and broad, multidisciplinary evidence for the effects of increasing [CO2 ] (iCO2 ) on the global terrestrial carbon sink. Evidence suggests a substantial increase in global photosynthesis since pre-industrial times. Established theory, supported by experiments, indicates that iCO2 is likely responsible for about half of the increase. Global carbon budgeting, atmospheric data, and forest inventories indicate a historical carbon sink, and these apparent iCO2 responses are high in comparison to experiments and predictions from theory. Plant mortality and soil carbon iCO2 responses are highly uncertain. In conclusion, a range of evidence supports a positive terrestrial carbon sink in response to iCO2 , albeit with uncertain magnitude and strong suggestion of a role for additional agents of global change.
234 citations
University of Calgary1, Swiss Federal Institute for Forest, Snow and Landscape Research2, Cooperative Institute for Research in Environmental Sciences3, ETH Zurich4, University of Washington5, University of Zurich6, University of Potsdam7, United States Geological Survey8, University of Minnesota9, University of Graz10, University of Natural Resources and Life Sciences, Vienna11, University of Toulouse12, University of Utah13, Heidelberg University14, University of Geneva15, University of Leeds16, Simon Fraser University17, Newcastle University18, University of Dayton19, University of Oslo20, Planetary Science Institute21, University of Alberta22, University of Grenoble23, University of Sheffield24, Indian Institute of Technology Indore25, UNESCO26, University of Dundee27, Jawaharlal Nehru University28, Stockholm International Water Institute29, University of British Columbia30, University of Exeter31, Kathmandu32, Wadia Institute of Himalayan Geology33, University of Kashmir34, University of Delhi35, Utrecht University36, International Centre for Integrated Mountain Development37, University of Chile38, Northumbria University39
TL;DR: In this paper, an analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice collapsed from the steep north face of Ronti Peak.
Abstract: On 7 Feb 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. Over 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice collapsed from the steep north face of Ronti Peak. The rock and ice avalanche rapidly transformed into an extraordinarily large and mobile debris flow that transported boulders >20 m in diameter, and scoured the valley walls up to 220 m above the valley floor. The intersection of the hazard cascade with downvalley infrastructure resulted in a disaster, which highlights key questions about adequate monitoring and sustainable development in the Himalaya as well as other remote, high-mountain environments.
201 citations
TL;DR: The updated taxonomy of Negarnaviricota is presented, as now accepted by the ICTV, after the phylum was amended and emended in March 2020.
Abstract: In March 2020, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. At the genus rank, 20 new genera were added, two were deleted, one was moved, and three were renamed. At the species rank, 160 species were added, four were deleted, ten were moved and renamed, and 30 species were renamed. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.
168 citations
Harvard University1, Stanford University2, Tel Aviv University3, American Museum of Natural History4, University of California, Santa Barbara5, Conservation International6, Food and Agriculture Organization7, University of Washington8, Carleton University9, United States Geological Survey10, Shanghai Jiao Tong University11, Environmental Defense Fund12, Duke University13, Cornell University14, University of Stirling15, WorldFish16, Johns Hopkins University17
TL;DR: In this article, a model that unifies terrestrial foods with nearly 3,000 aquatic foods to understand the future impact of aquatic foods on human nutrition is presented. And the authors show that an increase in aquatic animal-source food production could reduce the inadequate intake of most nutrients.
Abstract: Despite contributing to healthy diets for billions of people, aquatic foods are often undervalued as a nutritional solution because their diversity is often reduced to the protein and energy value of a single food type (‘seafood’ or ‘fish’)1–4. Here we create a cohesive model that unites terrestrial foods with nearly 3,000 taxa of aquatic foods to understand the future impact of aquatic foods on human nutrition. We project two plausible futures to 2030: a baseline scenario with moderate growth in aquatic animal-source food (AASF) production, and a high-production scenario with a 15-million-tonne increased supply of AASFs over the business-as-usual scenario in 2030, driven largely by investment and innovation in aquaculture production. By comparing changes in AASF consumption between the scenarios, we elucidate geographic and demographic vulnerabilities and estimate health impacts from diet-related causes. Globally, we find that a high-production scenario will decrease AASF prices by 26% and increase their consumption, thereby reducing the consumption of red and processed meats that can lead to diet-related non-communicable diseases5,6 while also preventing approximately 166 million cases of inadequate micronutrient intake. This finding provides a broad evidentiary basis for policy makers and development stakeholders to capitalize on the potential of aquatic foods to reduce food and nutrition insecurity and tackle malnutrition in all its forms. Data on the nutrient content of almost 3,000 aquatic animal-source foods is combined with a food-systems model to show that an increase in aquatic-food production could reduce the inadequate intake of most nutrients.
144 citations
Texas A&M University1, University of Exeter2, University of Helsinki3, Université du Québec à Montréal4, Tanjungpura University5, University of Hawaii at Manoa6, University of Bristol7, Bowdoin College8, Chulalongkorn University9, University of California, Los Angeles10, Max Planck Society11, University of Nottingham12, University of Magallanes13, Oeschger Centre for Climate Change Research14, Université de Montréal15, Northeast Normal University16, Lehigh University17, Mount Holyoke College18, McGill University19, Stockholm University20, University of Leicester21, Katholieke Universiteit Leuven22, University of St Andrews23, Florida State University24, Aarhus University25, University of Toronto26, University of New Hampshire27, University of Łódź28, Centre national de la recherche scientifique29, Cranfield University30, University of Alberta31, Stockholm Environment Institute32, Lawrence Berkeley National Laboratory33, United States Geological Survey34, Texas A&M University at Galveston35, University of Victoria36, Adam Mickiewicz University in Poznań37, Finnish Meteorological Institute38, Royal Holloway, University of London39, University of Queensland40, Lamont–Doherty Earth Observatory41, National Park Service42, University of York43, Hope College44, University of Reading45, Uva Wellassa University46, Queen's University Belfast47, University of California, Berkeley48, Memorial University of Newfoundland49
TL;DR: In this article, the authors define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future.
Abstract: The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland–carbon–climate nexus. Peatlands are impacted by climate and land-use changes, with feedback to warming by acting as either sources or sinks of carbon. Expert elicitation combined with literature review reveals key drivers of change that alter peatland carbon dynamics, with implications for improving models.
141 citations
Lawrence Berkeley National Laboratory1, National University of Singapore2, Stanford University3, National Ecological Observatory Network4, University of Wisconsin-Madison5, Oak Ridge National Laboratory6, McMaster University7, University of Nebraska–Lincoln8, University of California, Berkeley9, Agricultural Research Service10, University of British Columbia11, University of Colorado Boulder12, Ohio State University13, University of Florida14, University of Guelph15, University of Kansas16, Michigan State University17, Pacific Northwest National Laboratory18, United States Department of Agriculture19, University of New Mexico20, National Research Council21, Marine Biological Laboratory22, University of Alberta23, Virginia Commonwealth University24, University of Minnesota25, Dalhousie University26, Université de Montréal27, Carleton University28, Shinshu University29, Japan Agency for Marine-Earth Science and Technology30, Northern Arizona University31, Oregon State University32, Yale University33, Washington State University34, Harvard University35, Texas A&M University36, Indiana University37, Florida International University38, San Diego State University39, California State University, East Bay40, Wayne State University41, University of Sydney42, Wilfrid Laurier University43, University of Alabama44, Environment Canada45, United States Geological Survey46, Argonne National Laboratory47, Osaka Prefecture University48, University of Delaware49, University of Missouri50, University of Sheffield51
TL;DR: In this article, the authors evaluate the representativeness of flux footprints and evaluate potential biases as a consequence of the footprint-to-target-area mismatch, which can be used as a guide to identify site-periods suitable for specific applications.
137 citations
Boise State University1, University of New South Wales2, Ames Research Center3, United States Geological Survey4, Northern Arizona University5, Bermuda Institute of Ocean Sciences6, Goddard Space Flight Center7, University of South Florida8, California Institute of Technology9, University of Maryland, Baltimore County10, University of California, Santa Cruz11, Arizona State University12, United States Naval Research Laboratory13, Kent State University14, Joint Institute for Nuclear Research15, University of Nebraska–Lincoln16, University of California, Santa Barbara17, University of Zurich18, Brookhaven National Laboratory19, City University of New York20, University of California, Davis21, University of Massachusetts Amherst22, Universiti Sains Malaysia23, Universities Space Research Association24
TL;DR: The 2017-2027 National Academies' Decadal Survey, Thriving on Our Changing Planet, recommended Surface Biology and Geology (SBG) as a "designated targeted observable" (DO) as discussed by the authors.
135 citations
Lea Berrang-Ford1, A. R. Siders2, Alexandra Lesnikowski3, Alexandra Paige Fischer4 +147 more•Institutions (87)
TL;DR: In this article, the authors present a systematic and comprehensive global stocktake of implemented human adaptation to climate change and identify eight priorities for global adaptation research: assess the effectiveness of adaptation responses, enhance the understanding of limits to adaptation, enable individuals and civil society to adapt, include missing places, scholars and scholarship, understand private sector responses, improve methods for synthesizing different forms of evidence, assess the adaptation at different temperature thresholds, and improve the inclusion of timescale and the dynamics of responses.
Abstract: Assessing global progress on human adaptation to climate change is an urgent priority. Although the literature on adaptation to climate change is rapidly expanding, little is known about the actual extent of implementation. We systematically screened >48,000 articles using machine learning methods and a global network of 126 researchers. Our synthesis of the resulting 1,682 articles presents a systematic and comprehensive global stocktake of implemented human adaptation to climate change. Documented adaptations were largely fragmented, local and incremental, with limited evidence of transformational adaptation and negligible evidence of risk reduction outcomes. We identify eight priorities for global adaptation research: assess the effectiveness of adaptation responses, enhance the understanding of limits to adaptation, enable individuals and civil society to adapt, include missing places, scholars and scholarship, understand private sector responses, improve methods for synthesizing different forms of evidence, assess the adaptation at different temperature thresholds, and improve the inclusion of timescale and the dynamics of responses. Determining progress in adaptation to climate change is challenging, yet critical as climate change impacts increase. A stocktake of the scientific literature on implemented adaptation now shows that adaptation is mostly fragmented and incremental, with evidence lacking for its impact on reducing risk.
123 citations
TL;DR: The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.
Abstract: On the NASA 2020 rover mission to Jezero crater, the remote determination of the texture, mineralogy and chemistry of rocks is essential to quickly and thoroughly characterize an area and to optimize the selection of samples for return to Earth. As part of the Perseverance payload, SuperCam is a suite of five techniques that provide critical and complementary observations via Laser-Induced Breakdown Spectroscopy (LIBS), Time-Resolved Raman and Luminescence (TRR/L), visible and near-infrared spectroscopy (VISIR), high-resolution color imaging (RMI), and acoustic recording (MIC). SuperCam operates at remote distances, primarily 2–7 m, while providing data at sub-mm to mm scales. We report on SuperCam’s science objectives in the context of the Mars 2020 mission goals and ways the different techniques can address these questions. The instrument is made up of three separate subsystems: the Mast Unit is designed and built in France; the Body Unit is provided by the United States; the calibration target holder is contributed by Spain, and the targets themselves by the entire science team. This publication focuses on the design, development, and tests of the Mast Unit; companion papers describe the other units. The goal of this work is to provide an understanding of the technical choices made, the constraints that were imposed, and ultimately the validated performance of the flight model as it leaves Earth, and it will serve as the foundation for Mars operations and future processing of the data.
121 citations
TL;DR: Current available information relevant to problem formulation/prioritization, exposure, and hazard/effects of PFAS in the context of regulatory and ecological risk assessment activities from around the world are summarized.
Abstract: Per- and poly-fluoroalkyl substances (PFAS) encompass a large, heterogenous group of chemicals of potential concern to human health and the environment. Based on information for a few relatively well-understood PFAS such as perfluorooctane sulfonate and perfluorooctanoate, there is ample basis to suspect that at least a subset can be considered persistent, bioaccumulative, and/or toxic. However, data suitable for determining risks in either prospective or retrospective assessments are lacking for the majority of PFAS. In August 2019, the Society of Environmental Toxicology and Chemistry sponsored a workshop that focused on the state-of-the-science supporting risk assessment of PFAS. The present review summarizes discussions concerning the ecotoxicology and ecological risks of PFAS. First, we summarize currently available information relevant to problem formulation/prioritization, exposure, and hazard/effects of PFAS in the context of regulatory and ecological risk assessment activities from around the world. We then describe critical gaps and uncertainties relative to ecological risk assessments for PFAS and propose approaches to address these needs. Recommendations include the development of more comprehensive monitoring programs to support exposure assessment, an emphasis on research to support the formulation of predictive models for bioaccumulation, and the development of in silico, in vitro, and in vivo methods to efficiently assess biological effects for potentially sensitive species/endpoints. Addressing needs associated with assessing the ecological risk of PFAS will require cross-disciplinary approaches that employ both conventional and new methods in an integrated, resource-effective manner. Environ Toxicol Chem 2021;40:564-605. © 2020 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
University of Wisconsin-Madison1, Arizona State University2, University College London3, United States Geological Survey4, University of Melbourne5, Westminster College (Utah)6, Curtin University7, Columbia University8, University of Edinburgh9, Lawrence Livermore National Laboratory10, New Mexico Institute of Mining and Technology11, University of Queensland12, University of Alaska Fairbanks13, Oregon State University14, University of Glasgow15, University of St Andrews16, University of California, Berkeley17, Berkeley Geochronology Center18, University of Florida19, Auburn University20, VU University Amsterdam21, Rutgers University22, Centre national de la recherche scientifique23, University of Vermont24, Geological Survey of Canada25, Japanese Ministry of Agriculture, Forestry and Fisheries26, Japan Agency for Marine-Earth Science and Technology27, Chinese Academy of Sciences28, Freiberg University of Mining and Technology29, China University of Geosciences (Wuhan)30
TL;DR: The 40Ar/39Ar dating method is among the most versatile of geochronometers, having the potential to date a broad variety of K-bearing materials spanning from the time of Earth's formation into the historical realm.
Abstract: The 40Ar/39Ar dating method is among the most versatile of geochronometers, having the potential to date a broad variety of K-bearing materials spanning from the time of Earth’s formation into the historical realm. Measurements using modern noble-gas mass spectrometers are now producing 40Ar/39Ar dates with analytical uncertainties of ~0.1%, thereby providing precise time constraints for a wide range of geologic and extraterrestrial processes. Analyses of increasingly smaller subsamples have revealed age dispersion in many materials, including some minerals used as neutron fluence monitors. Accordingly, interpretive strategies are evolving to address observed dispersion in dates from a single sample. Moreover, inferring a geologically meaningful “age” from a measured “date” or set of dates is dependent on the geological problem being addressed and the salient assumptions associated with each set of data. We highlight requirements for collateral information that will better constrain the interpretation of 40Ar/39Ar data sets, including those associated with single-crystal fusion analyses, incremental heating experiments, and in situ analyses of microsampled domains. To ensure the utility and viability of published results, we emphasize previous recommendations for reporting 40Ar/39Ar data and the related essential metadata, with the amendment that data conform to evolving standards of being findable, accessible, interoperable, and reusable (FAIR) by both humans and computers. Our examples provide guidance for the presentation and interpretation of 40Ar/39Ar dates to maximize their interdisciplinary usage, reproducibility, and longevity.
Pennsylvania State University1, National Institutes of Health2, Johns Hopkins University3, United States Geological Survey4, University of Massachusetts Amherst5, University of Pittsburgh6, Johns Hopkins University Applied Physics Laboratory7, Emory University8, École Polytechnique Fédérale de Lausanne9, University of Florida10, University of Utah11, Veterans Health Administration12, University of Victoria13, Northeastern University14, University of Southern California15, University of Virginia16, Centers for Disease Control and Prevention17
TL;DR: In this paper, the authors used a multiple-model approach comprising six models to assess the potential course of COVID-19 in the United States across four scenarios with different vaccination coverage rates and effectiveness estimates and strength and implementation of nonpharmaceutical interventions (NPIs) (such as physical distancing and masking) over a 6-month period (April-September 2021) using data available through March 27, 2021 (4).
Abstract: After a period of rapidly declining U.S. COVID-19 incidence during January-March 2021, increases occurred in several jurisdictions (1,2) despite the rapid rollout of a large-scale vaccination program. This increase coincided with the spread of more transmissible variants of SARS-CoV-2, the virus that causes COVID-19, including B.1.1.7 (1,3) and relaxation of COVID-19 prevention strategies such as those for businesses, large-scale gatherings, and educational activities. To provide long-term projections of potential trends in COVID-19 cases, hospitalizations, and deaths, COVID-19 Scenario Modeling Hub teams used a multiple-model approach comprising six models to assess the potential course of COVID-19 in the United States across four scenarios with different vaccination coverage rates and effectiveness estimates and strength and implementation of nonpharmaceutical interventions (NPIs) (public health policies, such as physical distancing and masking) over a 6-month period (April-September 2021) using data available through March 27, 2021 (4). Among the four scenarios, an accelerated decline in NPI adherence (which encapsulates NPI mandates and population behavior) was shown to undermine vaccination-related gains over the subsequent 2-3 months and, in combination with increased transmissibility of new variants, could lead to surges in cases, hospitalizations, and deaths. A sharp decline in cases was projected by July 2021, with a faster decline in the high-vaccination scenarios. High vaccination rates and compliance with public health prevention measures are essential to control the COVID-19 pandemic and to prevent surges in hospitalizations and deaths in the coming months.
University of Washington1, United States Department of Agriculture2, Northern Arizona University3, California Department of Forestry and Fire Protection4, The Nature Conservancy5, University of California, Berkeley6, United States Geological Survey7, Pennsylvania State University8, Utah State University9, United States Department of State10, University of British Columbia11, University of Arizona12, United States Fish and Wildlife Service13, Oregon State University14
TL;DR: In this article, the authors provide a framework for assessing changes in landscape conditions and fire regimes and evaluate evidence of change in contemporary conditions relative to those maintained by active fire regimes, i.e., those uninterrupted by a century or more of human-induced fire exclusion.
Abstract: Implementation of wildfire- and climate-adaptation strategies in seasonally dry forests of western North America is impeded by numerous constraints and uncertainties. After more than a century of resource and land use change, some question the need for proactive management, particularly given novel social, ecological, and climatic conditions. To address this question, we first provide a framework for assessing changes in landscape conditions and fire regimes. Using this framework, we then evaluate evidence of change in contemporary conditions relative to those maintained by active fire regimes, i.e., those uninterrupted by a century or more of human-induced fire exclusion. The cumulative results of more than a century of research document a persistent and substantial fire deficit and widespread alterations to ecological structures and functions. These changes are not necessarily apparent at all spatial scales or in all dimensions of fire regimes and forest and nonforest conditions. Nonetheless, loss of the once abundant influence of low- and moderate-severity fires suggests that even the least fire-prone ecosystems may be affected by alteration of the surrounding landscape and, consequently, ecosystem functions. Vegetation spatial patterns in fire-excluded forested landscapes no longer reflect the heterogeneity maintained by interacting fires of active fire regimes. Live and dead vegetation (surface and canopy fuels) is generally more abundant and continuous than before European colonization. As a result, current conditions are more vulnerable to the direct and indirect effects of seasonal and episodic increases in drought and fire, especially under a rapidly warming climate. Long-term fire exclusion and contemporaneous social-ecological influences continue to extensively modify seasonally dry forested landscapes. Management that realigns or adapts fire-excluded conditions to seasonal and episodic increases in drought and fire can moderate ecosystem transitions as forests and human communities adapt to changing climatic and disturbance regimes. As adaptation strategies are developed, evaluated, and implemented, objective scientific evaluation of ongoing research and monitoring can aid differentiation of warranted and unwarranted uncertainties.
01 Jan 2021
TL;DR: In this article, the authors discuss the key physical processes driving vertical land motion in coastal areas and use space-borne and land-based measurement techniques, as well as models for simulating observed subsidence and predicting future trends.
Abstract: Coastal subsidence contributes to relative sea-level rise and exacerbates flooding hazards, with the at-risk population expected to triple by 2070. Natural processes of vertical land motion, such as tectonics, glacial isostatic adjustment and sediment compaction, as well as anthropogenic processes, such as fluid extraction, lead to globally variable subsidence rates. In this Review, we discuss the key physical processes driving vertical land motion in coastal areas. Use of space-borne and land-based techniques and the associated uncertainties for monitoring subsidence are examined, as are physics-based models used to explain contemporary subsidence rates and to obtain future projections. Steady and comparatively low rates of subsidence and uplift owing to tectonic processes and glacial isostatic adjustment can be assumed for the twenty-first century. By contrast, much higher and variable subsidence rates occur owing to compaction associated with sediment loading and fluid extraction, as well as large earthquakes. These rates can be up to two orders of magnitude higher than the present-day rate of global sea-level rise. Multi-objective predictive models are required to account for the underlying physical processes and socio-economic factors that drive subsidence. Measuring coastal subsidence is essential to evaluating hazards associated with sea-level rise. This Review discusses the processes driving coastal subsidence, space-borne and land-based measurement techniques, as well as models for simulating observed subsidence and predicting future trends.
TL;DR: This article proposed that complicating factors at two levels stymie predictions of drought-driven mortality: organismal-level physiological and site factors that obscure understanding of drought exposure and vulnerability and community-level ecological interactions, particularly with biotic agents whose effects on tree mortality may reverse expectations based on stress physiology.
Abstract: Widespread tree mortality following droughts has emerged as an environmentally and economically devastating 'ecological surprise'. It is well established that tree physiology is important in understanding drought-driven mortality; however, the accuracy of predictions based on physiology alone has been limited. We propose that complicating factors at two levels stymie predictions of drought-driven mortality: (i) organismal-level physiological and site factors that obscure understanding of drought exposure and vulnerability and (ii) community-level ecological interactions, particularly with biotic agents whose effects on tree mortality may reverse expectations based on stress physiology. We conclude with a path forward that emphasizes the need for an integrative approach to stress physiology and biotic agent dynamics when assessing forest risk to drought-driven morality in a changing climate.
TL;DR: In this paper, a review of science-based adaptation strategies for western North American (wNA) forests that include restoring active fire regimes and fostering resilient structure and composition of forested landscapes is presented.
Abstract: We review science-based adaptation strategies for western North American (wNA) forests that include restoring active fire regimes and fostering resilient structure and composition of forested landscapes. As part of the review, we address common questions associated with climate adaptation and realignment treatments that run counter to a broad consensus in the literature. These include the following: (1) Are the effects of fire exclusion overstated? If so, are treatments unwarranted and even counterproductive? (2) Is forest thinning alone sufficient to mitigate wildfire hazard? (3) Can forest thinning and prescribed burning solve the problem? (4) Should active forest management, including forest thinning, be concentrated in the wildland urban interface (WUI)? (5) Can wildfires on their own do the work of fuel treatments? (6) Is the primary objective of fuel reduction treatments to assist in future firefighting response and containment? (7) Do fuel treatments work under extreme fire weather? (8) Is the scale of the problem too great? Can we ever catch up? (9) Will planting more trees mitigate climate change in wNA forests? And (10) is post-fire management needed or even ecologically justified? Based on our review of the scientific evidence, a range of proactive management actions are justified and necessary to keep pace with changing climatic and wildfire regimes and declining forest heterogeneity after severe wildfires. Science-based adaptation options include the use of managed wildfire, prescribed burning, and coupled mechanical thinning and prescribed burning as is consistent with land management allocations and forest conditions. Although some current models of fire management in wNA are averse to short-term risks and uncertainties, the long-term environmental, social, and cultural consequences of wildfire management primarily grounded in fire suppression are well documented, highlighting an urgency to invest in intentional forest management and restoration of active fire regimes.
17 May 2021
TL;DR: It is shown that a PGRNN can improve prediction accuracy over that of physics-based models, while generating outputs consistent with physical laws, and is applicable more widely to a range of scientific and engineering disciplines where physics- based models are used.
Abstract: Physics-based models are often used to study engineering and environmental systems. The ability to model these systems is the key to achieving our future environmental sustainability and improving the quality of human life. This article focuses on simulating lake water temperature, which is critical for understanding the impact of changing climate on aquatic ecosystems and assisting in aquatic resource management decisions. General Lake Model (GLM) is a state-of-the-art physics-based model used for addressing such problems. However, like other physics-based models used for studying scientific and engineering systems, it has several well-known limitations due to simplified representations of the physical processes being modeled or challenges in selecting appropriate parameters. While state-of-the-art machine learning models can sometimes outperform physics-based models given ample amount of training data, they can produce results that are physically inconsistent. This article proposes a physics-guided recurrent neural network model (PGRNN) that combines RNNs and physics-based models to leverage their complementary strengths and improves the modeling of physical processes. Specifically, we show that a PGRNN can improve prediction accuracy over that of physics-based models (by over 20% even with very little training data), while generating outputs consistent with physical laws. An important aspect of our PGRNN approach lies in its ability to incorporate the knowledge encoded in physics-based models. This allows training the PGRNN model using very few true observed data while also ensuring high prediction accuracy. Although we present and evaluate this methodology in the context of modeling the dynamics of temperature in lakes, it is applicable more widely to a range of scientific and engineering disciplines where physics-based (also known as mechanistic) models are used.
TL;DR: The National Land Cover Database (NLCD) is an operational land cover monitoring program providing updated land cover and related information for the United States at five-year intervals.
University of Portsmouth1, Stockholm University2, Baylor University3, Jinan University4, United States Environmental Protection Agency5, Swedish University of Agricultural Sciences6, Environment Agency7, Federal Institute for Risk Assessment8, Goethe University Frankfurt9, Griffith University10, University of Lethbridge11, Environment Protection Authority12, United States Geological Survey13, Wageningen University and Research Centre14, Leibniz Association15, Monash University16, University of Tübingen17
TL;DR: In this paper, a workshop with international representatives from the fields of behavioral ecology, ecotoxicology, regulatory toxicology, neurotoxicology and risk assessment resulted in the formation of consensus perspectives and recommendations which promise to serve as a roadmap to advance interfaces among the basic and translational sciences, and regulatory practices.
Abstract: For decades, we have known that chemicals affect human and wildlife behavior. Moreover, due to recent technological and computational advances, scientists are now increasingly aware that a wide variety of contaminants and other environmental stressors adversely affect organismal behavior and subsequent ecological outcomes in terrestrial and aquatic ecosystems. There is also a groundswell of concern that regulatory ecotoxicology does not adequately consider behavior, primarily due to a lack of standardized toxicity methods. This has, in turn, led to the exclusion of many behavioral ecotoxicology studies from chemical risk assessments. To improve understanding of the challenges and opportunities for behavioral ecotoxicology within regulatory toxicology/risk assessment, a unique workshop with international representatives from the fields of behavioral ecology, ecotoxicology, regulatory (eco)toxicology, neurotoxicology, test standardization, and risk assessment resulted in the formation of consensus perspectives and recommendations, which promise to serve as a roadmap to advance interfaces among the basic and translational sciences, and regulatory practices.
Bat Conservation International1, United States Fish and Wildlife Service2, United States Department of Agriculture3, United States Geological Survey4, University of Saint Mary5, Tennessee Wildlife Resources Agency6, Maryland Department of Natural Resources Police7, Government of Newfoundland and Labrador8, Illinois Department of Natural Resources9, United States Forest Service10, Georgia Department of Natural Resources11, Delaware Department of Natural Resources and Environmental Control12, Minnesota Department of Natural Resources13, Pennsylvania Game Commission14, West Virginia Division of Natural Resources15, National Park Service16, Indiana Department of Natural Resources17, University of California, Santa Cruz18
TL;DR: In this article, the authors assessed the threat impact of an emerging infectious disease by uniting monitoring efforts across jurisdictional boundaries and demonstrated the importance of coordinated monitoring programs for data-driven conservation assessments and planning.
Abstract: Assessing the scope and severity of threats is necessary for evaluating impacts on populations to inform conservation planning. Quantitative threat assessment often requires monitoring programs that provide reliable data over relevant spatial and temporal scales, yet such programs can be difficult to justify until there is an apparent stressor. Leveraging efforts of wildlife management agencies to record winter counts of hibernating bats, we collated data for 5 species from over 200 sites across 27 U.S. states and 2 Canadian provinces from 1995 to 2018 to determine the impact of white-nose syndrome (WNS), a deadly disease of hibernating bats. We estimated declines of winter counts of bat colonies at sites where the invasive fungus that causes WNS (Pseudogymnoascus destructans) had been detected to assess the threat impact of WNS. Three species undergoing species status assessment by the U.S. Fish and Wildlife Service (Myotis septentrionalis, Myotis lucifugus, and Perimyotis subflavus) declined by more than 90%, which warrants classifying the severity of the WNS threat as extreme based on criteria used by NatureServe. The scope of the WNS threat as defined by NatureServe criteria was large (36% of Myotis lucifugus range) to pervasive (79% of Myotis septentrionalis range) for these species. Declines for 2 other species (Myotis sodalis and Eptesicus fuscus) were less severe but still qualified as moderate to serious based on NatureServe criteria. Data-sharing across jurisdictions provided a comprehensive evaluation of scope and severity of the threat of WNS and indicated regional differences that can inform response efforts at international, national, and state or provincial jurisdictions. We assessed the threat impact of an emerging infectious disease by uniting monitoring efforts across jurisdictional boundaries and demonstrated the importance of coordinated monitoring programs, such as the North American Bat Monitoring Program (NABat), for data-driven conservation assessments and planning.
Morton Arboretum1, Cardiff University2, Colorado State University3, Montgomery Botanical Center4, University of Sydney5, University of Bordeaux6, United States Geological Survey7, Copenhagen Zoo8, University of Sarajevo9, Natural Resources Defense Council10, International Center for Tropical Agriculture11, Stockholm University12, Australian National University13, Research Institute for Nature and Forest14, Michigan State University15, Cornell University16, University of Benghazi17, University of Edinburgh18, State University of Campinas19, National Centre for Biological Sciences20, University of Freiburg21, Murdoch University22, Environmental Protection Agency23, University of Novi Sad24
TL;DR: Developments in knowledge, technology, databases, practice, and capacity are reviewed to explore how they can support improved consideration of genetic diversity in global conservation policy commitments and enable countries to monitor, report on, and take action to maintain or restore genetic diversity.
Abstract: Global conservation policy and action have largely neglected protecting and monitoring genetic diversity-one of the three main pillars of biodiversity Genetic diversity (diversity within species) underlies species' adaptation and survival, ecosystem resilience, and societal innovation The low priority given to genetic diversity has largely been due to knowledge gaps in key areas, including the importance of genetic diversity and the trends in genetic diversity change; the perceived high expense and low availability and the scattered nature of genetic data; and complicated concepts and information that are inaccessible to policymakers However, numerous recent advances in knowledge, technology, databases, practice, and capacity have now set the stage for better integration of genetic diversity in policy instruments and conservation efforts We review these developments and explore how they can support improved consideration of genetic diversity in global conservation policy commitments and enable countries to monitor, report on, and take action to maintain or restore genetic diversity
United States Geological Survey1, Florida Fish and Wildlife Conservation Commission2, University of Arizona3, University of California, Berkeley4, Louisiana State University5, Kennedy Space Center6, University of British Columbia7, University of California, Santa Cruz8, Marathon Oil9, National Oceanic and Atmospheric Administration10
TL;DR: This paper examined the influence of extreme cold events on the northward range limits of a diverse group of tropical organisms, including terrestrial plants, coastal wetland plants and coastal fishes, sea turtles, terrestrial reptiles, amphibians, manatees, and insects.
Abstract: Tropicalization is a term used to describe the transformation of temperate ecosystems by poleward-moving tropical organisms in response to warming temperatures. In North America, decreases in the frequency and intensity of extreme winter cold events are expected to allow the poleward range expansion of many cold-sensitive tropical organisms, sometimes at the expense of temperate organisms. Although ecologists have long noted the critical ecological role of winter cold temperature extremes in tropical-temperate transition zones, the ecological effects of extreme cold events have been understudied, and the influence of warming winter temperatures has too often been left out of climate change vulnerability assessments. Here, we examine the influence of extreme cold events on the northward range limits of a diverse group of tropical organisms, including terrestrial plants, coastal wetland plants, coastal fishes, sea turtles, terrestrial reptiles, amphibians, manatees, and insects. For these organisms, extreme cold events can lead to major physiological damage or landscape-scale mass mortality. Conversely, the absence of extreme cold events can foster population growth, range expansion, and ecological regime shifts. We discuss the effects of warming winters on species and ecosystems in tropical-temperate transition zones. In the 21st century, climate change-induced decreases in the frequency and intensity of extreme cold events are expected to facilitate the poleward range expansion of many tropical species. Our review highlights critical knowledge gaps for advancing understanding of the ecological implications of the tropicalization of temperate ecosystems in North America.
National Oceanic and Atmospheric Administration1, United States Geological Survey2, National Park Service3, University of Alaska Fairbanks4, Alaska Department of Fish and Game5, United States Fish and Wildlife Service6, Alaska SeaLife Center7, University of Alaska Southeast8, Western Washington University9
TL;DR: In this paper, the authors present an analysis of 187 time series from primary production to commercial fisheries and nearshore intertidal to offshore oceanic domains demonstrating abrupt changes across trophic levels, with many responses persisting up to at least 5 years after the onset of the marine heatwave.
Abstract: Some of the longest and most comprehensive marine ecosystem monitoring programs were established in the Gulf of Alaska following the environmental disaster of the Exxon Valdez oil spill over 30 years ago. These monitoring programs have been successful in assessing recovery from oil spill impacts, and their continuation decades later has now provided an unparalleled assessment of ecosystem responses to another newly emerging global threat, marine heatwaves. The 2014–2016 northeast Pacific marine heatwave (PMH) in the Gulf of Alaska was the longest lasting heatwave globally over the past decade, with some cooling, but also continued warm conditions through 2019. Our analysis of 187 time series from primary production to commercial fisheries and nearshore intertidal to offshore oceanic domains demonstrate abrupt changes across trophic levels, with many responses persisting up to at least 5 years after the onset of the heatwave. Furthermore, our suite of metrics showed novel community-level groupings relative to at least a decade prior to the heatwave. Given anticipated increases in marine heatwaves under current climate projections, it remains uncertain when or if the Gulf of Alaska ecosystem will return to a pre-PMH state.
TL;DR: In this paper, the authors show how a global community is responding to the challenges of tropical ecosystem research with diverse teams measuring forests tree-by-tree in thousands of long-term plots.
TL;DR: In this article, the importance of plants and associated biological processes in determining the vulnerability of coastal wetlands to sea-level rise is evaluated, where plants influence sediment accretion, elevation capital (vertical position in the tidal frame), and compaction or erosion of deposited material.
Abstract: This review evaluates the importance of plants and associated biological processes in determining the vulnerability of coastal wetlands to sea-level rise. Coastal wetlands occur across a broad sedimentary continuum from minerogenic to biogenic, providing an opportunity to examine the relative importance of biological processes in wetland resilience to sea-level rise. We explore how plants influence sediment accretion, elevation capital (vertical position in the tidal frame), and compaction or erosion of deposited material. We focus on salt marsh and mangrove wetlands, which occupy a similar physiographic niche and display similar physical and biological controls on resilience to sea-level rise. In both habitats, plants stabilize emergent mudflats and help sustain the wetland position in the tidal frame relative to ocean height through both surface and subsurface process controls on soil elevation. Plants influence soil elevations by modifying (1) mineral sediment deposition and retention, (2) organic matter contributions to soil volume, and (3) resistance to compaction and erosion. Recognition of the importance of plants in coastal wetland resilience to sea-level rise is key to accurate predictions about the future fate of salt marshes and mangrove forests and for development of effective management and restoration plans.
Stanford University1, University of British Columbia2, University of Santiago, Chile3, Tuscia University4, Lawrence Berkeley National Laboratory5, International Rice Research Institute6, Finnish Meteorological Institute7, University of California, Berkeley8, United States Geological Survey9, University of Nebraska–Lincoln10, Ohio State University11, University of Florida12, ETH Zurich13, University of Waikato14, United States Department of the Interior15, State University System of Florida16, Michigan State University17, University College Dublin18, University of Alaska Fairbanks19, Karlsruhe Institute of Technology20, Max Planck Society21, University of Orléans22, VU University Amsterdam23, Landcare Research24, Université de Montréal25, Dalhousie University26, Centre national de la recherche scientifique27, University of Botswana28, Shinshu University29, North Carolina State University30, Weihenstephan-Triesdorf University of Applied Sciences31, Hokkaido University32, The Chinese University of Hong Kong33, University of Helsinki34, Wellesley College35, International Livestock Research Institute36, Northern Arizona University37, Swedish University of Agricultural Sciences38, Agricultural Research Service39, Russian Academy of Sciences40, Kyoto University41, Rutgers University42, National Ecological Observatory Network43, California State University44, University of Wisconsin-Madison45, United States Department of Agriculture46, Seoul National University47, University of Innsbruck48, University of Maryland, College Park49, University of Sheffield50, Université du Québec51, Cornell University52, Battelle Memorial Institute53, United States Department of Energy54, Osaka Prefecture University55, University of Delaware56, California State University San Marcos57
TL;DR: The FLUXNET-CH4 dataset as mentioned in this paper is the first open-source global dataset of CH4 EC measurements and includes half-hourly and daily gap-filled and non-gap-filled aggregated CH4 fluxes and meteorological data from 79 sites globally: 42 freshwater wetlands, 6 brackish and saline wetlands, 7 formerly drained ecosystems, 7 rice paddy sites, 2 lakes and 15 uplands.
Abstract: . Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions due to quasi-continuous and high-temporal-resolution CH4 flux measurements, coincident carbon dioxide, water, and energy flux measurements, lack of ecosystem disturbance, and increased availability of datasets over the last decade. Here, we (1) describe the newly published dataset, FLUXNET-CH4 Version 1.0, the first open-source global dataset of CH4 EC measurements (available at https://fluxnet.org/data/fluxnet-ch4-community-product/, last access: 7 April 2021). FLUXNET-CH4 includes half-hourly and daily gap-filled and non-gap-filled aggregated CH4 fluxes and meteorological data from 79 sites globally: 42 freshwater wetlands, 6 brackish and saline wetlands, 7 formerly drained ecosystems, 7 rice paddy sites, 2 lakes, and 15 uplands. Then, we (2) evaluate FLUXNET-CH4 representativeness for freshwater wetland coverage globally because the majority of sites in FLUXNET-CH4 Version 1.0 are freshwater wetlands which are a substantial source of total atmospheric CH4 emissions; and (3) we provide the first global estimates of the seasonal variability and seasonality predictors of freshwater wetland CH4 fluxes. Our representativeness analysis suggests that the freshwater wetland sites in the dataset cover global wetland bioclimatic attributes (encompassing energy, moisture, and vegetation-related parameters) in arctic, boreal, and temperate regions but only sparsely cover humid tropical regions. Seasonality metrics of wetland CH4 emissions vary considerably across latitudinal bands. In freshwater wetlands (except those between 20∘ S to 20∘ N) the spring onset of elevated CH4 emissions starts 3 d earlier, and the CH4 emission season lasts 4 d longer, for each degree Celsius increase in mean annual air temperature. On average, the spring onset of increasing CH4 emissions lags behind soil warming by 1 month, with very few sites experiencing increased CH4 emissions prior to the onset of soil warming. In contrast, roughly half of these sites experience the spring onset of rising CH4 emissions prior to the spring increase in gross primary productivity (GPP). The timing of peak summer CH4 emissions does not correlate with the timing for either peak summer temperature or peak GPP. Our results provide seasonality parameters for CH4 modeling and highlight seasonality metrics that cannot be predicted by temperature or GPP (i.e., seasonality of CH4 peak). FLUXNET-CH4 is a powerful new resource for diagnosing and understanding the role of terrestrial ecosystems and climate drivers in the global CH4 cycle, and future additions of sites in tropical ecosystems and site years of data collection will provide added value to this database. All seasonality parameters are available at https://doi.org/10.5281/zenodo.4672601 (Delwiche et al., 2021). Additionally, raw FLUXNET-CH4 data used to extract seasonality parameters can be downloaded from https://fluxnet.org/data/fluxnet-ch4-community-product/ (last access: 7 April 2021), and a complete list of the 79 individual site data DOIs is provided in Table 2 of this paper.
California Institute of Technology1, Purdue University2, Planetary Science Institute3, Northern Arizona University4, University of Nantes5, United States Geological Survey6, University of Arizona7, Stanford University8, Colgate University9, University of Colorado Boulder10, United States Naval Research Laboratory11
TL;DR: In this article, the authors outline currently observed and interpreted surface activity occurring within the modern Mars environment, and tie this activity to wind, seasonal surface CO2 frost/ice, sublimation of subsurface water ice, and/or gravity drivers.
TL;DR: This is the first assessment of groundwater from public-supply wells across the United States to analyze for >100 pesticide degradates and to provide human-health context for degradate without benchmarks, and concentrations were low.
Abstract: This is the first assessment of groundwater from public-supply wells across the United States to analyze for >100 pesticide degradates and to provide human-health context for degradates without benchmarks. Samples from 1204 wells in aquifers representing 70% of the volume pumped for drinking supply were analyzed for 109 pesticides (active ingredients) and 116 degradates. Among the 41% of wells where pesticide compounds were detected, nearly two-thirds contained compound mixtures and three-quarters contained degradates. Atrazine, hexazinone, prometon, tebuthiuron, four atrazine degradates, and one metolachlor degradate were each detected in >5% of wells. Detection frequencies were largest for aquifers with more shallow, unconfined wells producing modern-age groundwater. To screen for potential human-health concerns, benchmark quotients (BQs) were calculated by dividing concentrations by the human-health benchmark, when available. For degradates without benchmarks, estimated values (estimated benchmark quotients (BQE)) were first calculated by assuming equimolar toxicity to the most toxic parent; final analysis excluded degradates with likely overestimated toxicity. Six pesticide compounds and 1.6% of wells had concentrations approaching levels of potential concern (individual or summed BQ or BQE values >0.1), and none exceeded these levels (values >1). Therefore, although pesticide compounds occurred frequently, concentrations were low, even accounting for mixtures and degradates without benchmarks.