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The Cascadia Subduction Zone, located in the U.S. Pacific Northwest and southwestern British Columbia, has hosted magnitude ≥8.0 megathrust earthquakes in the geologic past, a future earthquake is imminent, and the potential impacts could cripple the region. Subduction zone earthquakes represent some of the most devastating natural hazards on Earth. Despite substantial knowledge gained from decades of geoscience research, the size and frequency of Cascadian earthquakes remain controversial, as do the physics of earthquake rupture, the effects of earthquake shaking, and the effect of resultant tsunamis. This translates into major uncertainties in earthquake hazard assessments that can lead to ineffective preparedness...
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Cascadia Subduction Zone,
Earthquakes,
Natural Hazards,
Streamflow is declining in many parts of the United States (US) due to factors including groundwater pumping, land use change, and climate change. Streamflow depletion, a reduction in groundwater discharge to a stream due to human activities such as pumping and/or land use change, tends to evolve slowly and can be entirely invisible for many years to decades. This is because streamflow depletion can be masked by the natural and/or climate change-induced variability in streamflow, and groundwater storage can buffer the impacts on streams. The negative effects on both anthropogenic and ecological systems can evolve over decades or more, and specific causes and potential solutions to these issues are often difficult...
The three-dimensional (3D) form of the Earth’s surface results from both abiotic and biotic forces. Major abiotic forces, such as tectonic uplift, erosion, and climate, exert strong influence over land surface morphology. Biotic forces, including, significantly, humans, also shape the landscape, but often at different temporal and spatial scales and magnitudes than geologic forces. Because the processes shaping the land surface, as expressed in its topography, are ongoing, topographic change is ever present and is a factor that must be broadly considered in studies of natural and built environments. Remote sensing data, especially in the form of derived high-resolution measurements of the topography, have been widely...
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Land Resources,
Land Resources,
Land Resources,
Dam decommissioning is rapidly emerging as an important river restoration strategy in the U.S., with several major removals recently completed or in progress. But few studies have evaluated the far-reaching consequences of these significant environmental perturbations, especially those resulting from removals of large (>10-15 m tall) structures during the last decade. In particular, interactions between physical and ecological aspects of dam removal are poorly known. From recent work, however, observations are now available from several diverse settings nationwide to allow synthesis of key physical and ecological processes associated with dam removals, including fish and benthic community response, reservoir erosion,...
Drylands are integral to the Earth system and the present and future of human society. Drylands encompass more than 40% of the terrestrial landmass and support 34% of the world’s human population. Biocrusts are the “living skin” of Earth’s drylands, sometimes dominating the ground cover and figuring prominently in ecosystem structure and function. Biocrusts are a biological aggregate of cyanobacteria, fungi, algae, lichens and mosses in the surface millimeters of soil. By aggregating soil, biocrusts make sediment less erodible. They also strongly influence the water runoff-infiltration balance. In some ecosystems they generate runoff, whereas in other systems they enhance water capture. Vascular plant germination,...
A vast number of the world’s volcanoes are unmonitored by ground-based sensors, yet constitute an important hazard to nearby residents and infrastructure, as well as air travel and the global economy. Satellite data provide a cost-effective means of tracking activity at such volcanoes. Unfortunately, satellite acquisitions are not optimized for application to volcano hazards, in part because clear relations between satellite-monitored unrest and eruptive activity are lacking. We aim to bridge this gap by developing linked global databases of satellite observations of volcanic activity, with the goal of relating surface change and volcanic emissions to eruption style and impact. This database (or databases) will...
This proposal brings together biologists and geoscientists to evaluate the evolution of stress tolerance and adaptation to extreme environments in plants. Stress tolerance has been studied mainly from a physiological perspective using laboratory and field experiments. In contrast, this project will take a combined environmental and evolutionary perspective using national public databases and a “big data” approach. Thus the proposal will illustrate an application of spatially integrated big datasets for basic research, a synthesis goal of the Powell Center. We will use the geochemical and mineralogical data from the USGS Soil Geochemical Landscapes of the Conterminous United States Project, digital elevation and...
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Ecosystems,
Energy and Minerals,
Land Resources,
Terrestrial evapotranspiration (ET), the second-largest component of the terrestrial water cycle, links water, energy, and carbon cycles and influences the productivity and health of our ecosystems. Despite the importance of ET, the dynamics of ET across a spectrum of spatiotemporal scale and their controls are uncertain. During an international ET workshop held in November 2021 by AmeriFlux, the scientific community identified key challenges to improve our understanding of ET dynamics. Participants underscored the need for an integrated understanding of ET across the different research disciplines: in-situ measurements, remote sensing, and modeling. Here, we propose the synthesis of the three research areas to...
Groundwater contaminated with naturally occurring arsenic is a widespread problem affecting many alluvial and deltaic aquifer systems throughout the world. The human health toll from consuming groundwater with high levels of arsenic is staggering in its proportions. Furthermore, the use of arsenic contaminated groundwater for irrigation is observed to result in diminished crop yields and thus poses a threat to food security in arsenic affected regions. Decades of research at individual field sites have resulted in the collection of many geochemical and geologic datasets. A key feature of alluvial and deltaic aquifer systems is the large degree of spatial variability in groundwater arsenic concentrations from local...
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Environmental Health,
Water Resources,
arsenic,
Despite the critical services freshwater systems provide, freshwater biodiversity has been vastly under-studied compared to terrestrial and marine biomes. In fact, systematic compilations of freshwater zooplankton are surprisingly rare despite the critical roles zooplankton play in regulating and supporting ecosystem services, serving as key indicator species, and consequently, influencing emergent system properties such as water quality and food web structure. We have compiled and harmonized the most temporally and spatially extensive freshwater zooplankton dataset available to date, designed to seamlessly integrate with a suite of in-lake and remote sensing data and modeling products. Our international team will...
The impacts of nitrogen (N) deposition on plant diversity loss have been well documented across N deposition gradients in Europe, but much less so in the U.S. Published N fertilizer studies suggest losses will occur in the US, but many of these were done at levels of N input that were higher than modeled and measured N deposition, and higher than presumed N critical loads. The recent availability of modeled N deposition across the U.S. (e.g. using CMAQ) has provided a highâresolution tool to identify regions where steep N deposition gradients facilitate detection of ecological shifts. A number of plant diversity (richness plus abundance) data sets across the U.S. have explained diversity shifts based on anthropogenic...
Streams and rivers have a limited spatial extent, but are increasingly recognized as key components of regional biogeochemical cycles. The collective metabolic processing of organisms, known as ecosystem metabolism, is centrally important to nutrient cycling and carbon fluxes in these environments, but is poorly integrated into emerging biogeochemical concepts. This line of inquiry lags behind other aspects of regional biogeochemistry because of the lack of long-term, regionally-diverse studies of stream metabolism. With a few exceptions, metabolism studies have focused on small headwater catchments using short-term (days to weeks) observation. As a consequence, basic patterns and controls of this fundamental process,...
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Aquatic carbon,
Ecosystems,
Water Quality,
Subsurface preferential flow (PF = water bypassing the soil matrix) provides rapid flowpaths for water and any substances transported with it, thereby profoundly impacting the recharge of aquifers, the spreading of contaminants, the health of the soil, and the functioning of ecosystems. It involves a complexity of processes that are poorly understood to the degree that current science provides no reliable way to predict its occurrence and magnitude. This effort will address the fundamental question of where and when PF occurs, taking advantage of two recent scientific developments: availability of high frequency (at least every 30 minutes), multi-depth soil moisture data suitable to detect preferential flow events...
Water in the United States is used for myriad activities on a daily basis, such as for food (irrigation, aquaculture, livestock), energy (thermoelectric power or hydropower generation), and public water supply for domestic, commercial or industrial purposes. Yet, we lack an national accounting of how and where water is used on a temporal scale more frequent than every 5 years, and a spatial scale greater than county level. The “water data drought” in the U.S. and globally is one of the key barriers inhibiting our understanding of how the environment sustains society and how society alters the environment. The world’s best mesoscale water use dataset is the USGS Water-Use report (the so-called “water census”), which...
Regional- to continental-scale paleoclimate syntheses of temperature and hydroclimate in North America are essential for understanding long-term spatiotemporal variability in climate, and for properly assessing risk on decadal and longer timescales. However, existing syntheses rely almost exclusively on tree-ring records, which are known to underestimate low-frequency variability and rarely extend beyond the last millennium. Meanwhile, many additional records from a variety of archives are available and hold the potential of broadening and enhancing our understanding of past climate in North America over the past two thousand years. We propose to bring together a diverse group of with expertise that spans the relevant...
Rivers are the veins of the landscape, providing environmental benefits that are disproportionately high relative to their aerial extent; shedding flood waters, hosting aquatic ecosystems, transporting solutes and energy-rich materials, and storing and transforming pollutants into less harmful forms. From uplands to the coasts, rivers facilitate key biogeochemical reactions that cumulatively influence water quality. Many of the reactions are optimized outside the main channel, in hyporheic zones, riparian zones, and floodplain areas, where riverine water is in close contact with geochemically and microbially-active sediments. However, little is known about the distribution, intermittency, and overall effectiveness...
Coral reefs are massive, wave resistant structures found throughout the tropics, where they have long attracted attention for their beauty, ecological importance, and rich biological diversity. However, in recent years attention to these systems has focused on their downturn in health and the potential that they effectively could disappear within a century. Yet while many coral reefs have deteriorated, a small number have flourished and now represent “oases” with the potential to drive repopulation of the denuded areas that surround them. This working group focuses on the geographic, biological, ecological, and physical features that characterize oases in coral reef communities, and evaluates the potential of...
Our ability to effectively manage natural resources is founded in an understanding of how our actions and the environment influence populations, communities, and ecosystems. Current practices use monitoring data from the past to determine key ecological relationships and make predictions about the future with the assumption that those relationships will remain constant. However, many natural systems are undergoing rapid changes due to external factors including climate change, urbanization, and energy development, leading to a situation in which our observations of the past are poor predictors of the future. Ignoring such changes could lead to management decisions that are sub-optimal at best or detrimental at worst....
Drought impacts on terrestrial ecosystems have increased globally in the 21st century, and droughts are expected to become more frequent, extreme, and spatially extensive in the future. Historical site-based observations are inadequate to predict how future extreme water deficits will affect the global terrestrial surface, because future droughts and their impacts may be more extreme than they have been historically and reach well beyond a single ecosystem. This USGS Powell Center working group will conduct the first comprehensive synthesis of ecosystem impacts across a coordinated, globally distributed drought experiment network of over 100 sites that have imposed an extreme multi-year drought. Knowledge about...
Groundwater plays a critical role in the water balance, however the groundwater component of the hydrologic cycle is frequently overlooked at basin scales because it is difficult to observe and quantify. We address this problem through a novel framework that combines existing hydrological models and data sets with groundwater flux estimates across Earth's largest system of lakes; the Laurentian Great Lakes. Aside from serving as a template for combining surface and ground water data and models, the Laurentian Great Lakes recently transitioned from a period characterized by water scarcity (water levels on the lakes were persistently below average from 1998 through 2013) to extreme water abundance (all-time high...
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