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At least 1,585 records · Page 88Linked to original sources
USGS2018

Juvenile coho salmon growth and health in streams across an urbanization gradient

Expanding human population and urbanization alters freshwater systems through structural changes to habitat, temperature effects from increased runoff and reduced canopy cover, altered flows, and increased toxicants. Current stream assessments stop short of measuring health or condition of species utilizing these freshwater habitats and fail to link specific stressors mechanistically to the health of organisms in the stream. Juvenile fish growth integrates both external and internal conditions providing a useful indicator of habitat quality and ecosystem health. Thus, there is a need to account for ecological and environmental influences on fish growth accurately. Bioenergetics models can simulate changes in growth and consumption in response to environmental conditions and food availability to account for interactions between an organism's environmental experience and utilization of available resources. The bioenergetics approach accounts for how thermal regime, food supply, and food quality affect fish growth. This study used a bioenergetics modeling approach to evaluate the environmental factors influencing juvenile coho salmon growth among ten Pacific Northwest streams spanning an urban gradient. Urban streams tended to be warmer, have earlier emergence dates and stronger early season growth. However, fish in urban streams experienced increased stress through lower growth efficiencies, especially later in the summer as temperatures warmed, with as much as a 16.6% reduction when compared to fish from other streams. Bioenergetics modeling successfully characterized salmonid growth in small perennial streams as part of a more extensive monitoring program and provides a powerful assessment tool for characterizing mixed life-stage specific responses in urban streams.

Science of the Total Environment↗
USGS2022

The role of satellite telemetry data in 21st century conservation of polar bears (Ursus maritimus)

Satellite telemetry (ST) has played a critical role in the management and conservation of polar bears ( Ursus maritimus ) over the last 50 years. ST data provide biological information relevant to subpopulation delineation, movements, habitat use, maternal denning, health, human-bear interactions, and accurate estimates of vital rates and abundance. Given that polar bears are distributed at low densities over vast and remote habitats, much of the information provided by ST data cannot be collected by other means. Obtaining ST data for polar bears requires chemical immobilization and application of a tracking device. Although immobilization has not been found to have negative effects beyond a several-day reduction in activity, over the last few decades opposition to immobilization and deployment of satellite-linked radio collars has resulted in a lack of current ST data in many of the 19 recognized polar bear subpopulations. Here, we review the uses of ST data for polar bears and evaluate its role in addressing 21 st century conservation and management challenges, which include estimation of sustainable harvest rates, understanding the impacts of climate warming, delineating critical habitat, and assessing potential anthropogenic impacts from tourism, resource development and extraction. We found that in subpopulations where ST data have been consistently collected, information was available to estimate vital rates and subpopulation density, document the effects of sea-ice loss, and inform management related to subsistence harvest and regulatory requirements. In contrast, a lack of ST data in some subpopulations resulted in increased bias and uncertainty in ecological and demographic parameters, which has a range of negative consequences. As sea-ice loss due to climate warming continues, there is a greater need to monitor polar bear distribution, habitat use, abundance, and subpopulation connectivity. We conclude that continued collection of ST data will be critically important for polar bear management and conservation in the 21 st century and that the benefits of immobilizing small numbers of individual polar bears in order to deploy ST devices significantly outweigh the risks.

Frontiers in Marine Science↗
USGS2015

Linking state-and-transition simulation and timber supply models for forest biomass production scenarios

We linked state-and-transition simulation models (STSMs) with an economics-based timber supply model to examine landscape dynamics in North Carolina through 2050 for three scenarios of forest biomass production. Forest biomass could be an important source of renewable energy in the future, but there is currently much uncertainty about how biomass production would impact landscapes. In the southeastern US, if forests become important sources of biomass for bioenergy, we expect increased land-use change and forest management. STSMs are ideal for simulating these landscape changes, but the amounts of change will depend on drivers such as timber prices and demand for forest land, which are best captured with forest economic models. We first developed state-and-transition model pathways in the ST-Sim software platform for 49 vegetation and land-use types that incorporated each expected type of landscape change. Next, for the three biomass production scenarios, the SubRegional Timber Supply Model (SRTS) was used to determine the annual areas of thinning and harvest in five broad forest types, as well as annual areas converted among those forest types, agricultural, and urban lands. The SRTS output was used to define area targets for STSMs in ST-Sim under two scenarios of biomass production and one baseline, business-as-usual scenario. We show that ST-Sim output matched SRTS targets in most cases. Landscape dynamics results indicate that, compared with the baseline scenario, forest biomass production leads to more forest and, specifically, more intensively managed forest on the landscape by 2050. Thus, the STSMs, informed by forest economics models, provide important information about potential landscape effects of bioenergy production.

AIMS Environmental Science↗
USGS2011

Oxidative dissolution of biogenic uraninite in groundwater at Old Rifle, CO

Reductive bioremediation is currently being explored as a possible strategy for uranium-contaminated aquifers such as the Old Rifle site (Colorado). The stability of U(IV) phases under oxidizing conditions is key to the performance of this procedure. An in situ method was developed to study oxidative dissolution of biogenic uraninite (UO 2 ), a desirable U(VI) bioreduction product, in the Old Rifle, CO, aquifer under different variable oxygen conditions. Overall uranium loss rates were 50–100 times slower than laboratory rates. After accounting for molecular diffusion through the sample holders, a reactive transport model using laboratory dissolution rates was able to predict overall uranium loss. The presence of biomass further retarded diffusion and oxidation rates. These results confirm the importance of diffusion in controlling in-aquifer U(IV) oxidation rates. Upon retrieval, uraninite was found to be free of U(VI), indicating dissolution occurred via oxidation and removal of surface atoms. Interaction of groundwater solutes such as Ca 2+ or silicate with uraninite surfaces also may retard in-aquifer U loss rates. These results indicate that the prolonged stability of U(IV) species in aquifers is strongly influenced by permeability, the presence of bacterial cells and cell exudates, and groundwater geochemistry.

Colorado↗
USGS2016

Climate change and the Delta

Anthropogenic climate change amounts to a rapidly approaching, “new” stressor in the Sacramento–San Joaquin Delta system. In response to California’s extreme natural hydroclimatic variability, complex water-management systems have been developed, even as the Delta’s natural ecosystems have been largely devastated. Climate change is projected to challenge these management and ecological systems in different ways that are characterized by different levels of uncertainty. For example, there is high certainty that climate will warm by about 2°C more (than late-20th-century averages) by mid-century and about 4°C by end of century, if greenhouse-gas emissions continue their current rates of acceleration. Future precipitation changes are much less certain, with as many climate models projecting wetter conditions as drier. However, the same projections agree that precipitation will be more intense when storms do arrive, even as more dry days will separate storms. Warmer temperatures will likely enhance evaporative demands and raise water temperatures. Consequently, climate change is projected to yield both more extreme flood risks and greater drought risks. Sea level rise (SLR) during the 20th century was about 22cm, and is projected to increase by at least 3-fold this century. SLR together with land subsidence threatens the Delta with greater vulnerabilities to inundation and salinity intrusion. Effects on the Delta ecosystem that are traceable to warming include SLR, reduced snowpack, earlier snowmelt and larger storm-driven streamflows, warmer and longer summers, warmer summer water temperatures, and water-quality changes. These changes and their uncertainties will challenge the operations of water projects and uses throughout the Delta’s watershed and delivery areas. Although the effects of climate change on Delta ecosystems may be profound, the end results are difficult to predict, except that native species will fare worse than invaders. Successful preparation for the coming changes will require greater integration of monitoring, modeling, and decision making across time, variables, and space than has been historically normal.

San Francisco Estuary and Watershed Science↗
USGS2018

Real-time nowcasting of microbiological water quality at recreational beaches: A wavelet and artificial neural network-based hybrid modeling approach

The number of beach closings caused by bacterial contamination has continued to rise in recent years, putting beachgoers at risk of exposure to contaminated water. Current approaches predict levels of indicator bacteria using regression models containing a number of explanatory variables. Data-based modeling approaches can supplement routine monitoring data and provide highly accurate short-term forecasts of beach water quality. In this paper, we apply the nonlinear autoregressive network with exogenous inputs (NARX) method with explanatory variables to predict Escherichia coli concentrations at four Lake Michigan beach sites. We also apply the nonlinear input–output network (NIO) and nonlinear autoregressive neural network (NAR) methods in addition to a hybrid wavelet-NAR (WA-NAR) model and demonstrate their application. All models were tested using 3 months of observed data. Results revealed that the NARX models provided the best performance and that the WA-NAR model, which requires no explanatory variables, outperformed the NIO and NAR models; therefore, the WA-NAR model is suitable for application to data scarce regions. The models proposed in this paper were evaluated using multiple performance metrics, including sensitivity and specificity measures, and produced results comparable or superior to those of previous mechanistic and statistical models developed for the same beach sites. The relatively high R 2 values between data and the NARX models ( R 2 values of ∼0.8 for the beach sites and ∼0.9 for the river site) indicate that the new class of models shows promise for beach management.

Environmental Science & Technology↗
USGS2019

An integrated statistical and deterministic hydrologic model for analyzing trace organic contaminants in commercial and high-density residential stormwater runoff

Urbanization can dramatically alter stormwater, both the quantity and quality, by engendering larger peak flows and through the introduction of contaminants into runoff. The current study builds on previous research that developed relationships between a suite of nonpoint source contaminants, known as trace organic contaminants (TOrCs), and hydrologic measurements for a series of storms (one site had 15 storms and the other had 19 storms) in Madison, WI, by creating statistical and deterministic models. Correlations and regressions were calculated between TOrC loads and hydrologic measurements for a series of storms for both a commercial site and a high-density residential site. From the regressions, it became evident that loading responses to precipitation were not the same between the two land covers for some TOrCs, indicating varying load responses for TOrCs depending on land cover. The regressions were utilized in the Source Loading and Management Model for Windows (WinSLAMM), an event-based hydrologic and water-quality model, to demonstrate that it can be used to model novel contaminants. The regressions were also used to estimate mean annual loads of TOrCs from all commercial and high-density residential areas in Madison, WI, for the watersheds to which Madison discharges its stormwater. The mean annual loads varied between grams per year to tens of thousands of grams per year depending on the TOrC and watershed. This work will ultimately allow managers to simulate the presence of, establish total maximum daily loads for, and mitigate the loads of TOrCs through stormwater best management practices.

Wisconsin↗
USGS2017

An “EAR” on environmental surveillance and monitoring: A case study on the use of Exposure–Activity Ratios (EARs) to prioritize sites, chemicals, and bioactivities of concern in Great Lakes waters

Current environmental monitoring approaches focus primarily on chemical occurrence. However, based on concentration alone, it can be difficult to identify which compounds may be of toxicological concern and should be prioritized for further monitoring, in-depth testing, or management. This can be problematic because toxicological characterization is lacking for many emerging contaminants. New sources of high-throughput screening (HTS) data, such as the ToxCast database, which contains information for over 9000 compounds screened through up to 1100 bioassays, are now available. Integrated analysis of chemical occurrence data with HTS data offers new opportunities to prioritize chemicals, sites, or biological effects for further investigation based on concentrations detected in the environment linked to relative potencies in pathway-based bioassays. As a case study, chemical occurrence data from a 2012 study in the Great Lakes Basin along with the ToxCast effects database were used to calculate exposure–activity ratios (EARs) as a prioritization tool. Technical considerations of data processing and use of the ToxCast database are presented and discussed. EAR prioritization identified multiple sites, biological pathways, and chemicals that warrant further investigation. Prioritized bioactivities from the EAR analysis were linked to discrete adverse outcome pathways to identify potential adverse outcomes and biomarkers for use in subsequent monitoring efforts.

Great Lakes↗
USGS2013

Effects of climate change and urban development on the distribution and conservation of vegetation in a Mediterranean type ecosystem

Climate and land-use changes are projected to threaten biodiversity over this century. However, few studies have considered the spatial and temporal overlap of these threats to evaluate how ongoing land-use change could affect species ranges projected to shift outside conservation areas. We evaluated climate change and urban development effects on vegetation distribution in the Southwest ecoregion, California Floristic Province, USA. We also evaluated how well a conservation network protects suitable habitat for rare plant species under these change projections and identified primary sources of uncertainty. We used consensus-based maps from three species distribution models (SDMs) to project current and future suitable habitat for 19 species representing different functional types (defined by fire-response – obligate seeders, resprouting shrubs – and life forms – herbs, subshrubs), and range sizes (large/common, small/rare). We used one spatially explicit urban growth projection; two climate models, emission scenarios, and probability thresholds applied to SDMs; and high-resolution (90 m) environmental data. We projected that suitable habitat could disappear for 4 species and decrease for 15 by 2080. Averaged centroids of suitable habitat (all species) were projected to shift tens (up to hundreds) of kilometers. Herbs showed a small-projected response to climate change, while obligate seeders could suffer the greatest losses. Several rare species could lose suitable habitat inside conservation areas while increasing area outside. We concluded that (i) climate change is more important than urban development for vegetation habitat loss in this ecoregion through 2080 due to diminishing amounts of undeveloped private land in this region; (ii) the existing conservation plan, while extensive, may be inadequate to protect plant diversity under projected patterns of climate change and urban development, (iii) regional assessments of the dynamics of the drivers of biodiversity change based on high-resolution environmental data and consensus predictive mapping, such as this study, are necessary to identify the species expected to be the most vulnerable and to meaningfully inform regional-scale conservation.

California↗
USGS2008

Environmental occurrence of the enterococcal surface protein ( esp ) gene is an unreliable indicator of human fecal contamination

The enterococcal surface protein ( esp ) gene found in Enterococcus faecalis and E. faecium has recently been explored as a marker of sewage pollution in recreational waters but its occurrence and distribution in environmental enterococci has not been well-documented. If the esp gene is found in environmental samples, there are potential implications for microbial source tracking applications. In the current study, a total of 452 samples (lake water, 100; stream water, 129; nearshore sand, 96; and backshore sand, 71; Cladophora sp. (Chlorophyta), 41; and periphyton (mostly Bacillariophyceae ), 15) collected from the coastal watersheds of southern Lake Michigan were selectively cultured for enterococci and then analyzed for the esp gene by PCR, targeting E. faecalis/ E. faecium ( esp fs/fm ) and E. faecium ( esp fm ). Overall relative frequencies for esp fs/fm and esp fm were 27.4 and 5.1%. Respective percent frequency for the esp fs/fm and esp fm was 36 and 14% in lake water; 38.8 and 2.3% in stream water; 24 and 6.3% in nearshore sand; 0% in backshore sand; 24.4 and 0% in Cladophora sp.; and 33.3 and 0% in periphyton. The overall occurrence of both esp fs/fm and esp fm was significantly related ( χ 2 = 49, P < 0.0001). Post-rain incidence of esp fs/fm increased in lake and stream water and nearshore sand. Further, E. coli and enterococci cell densities were significant predictors for esp fs/fm occurrence in post-rain lake water, but esp fm was not. F + coliphage densities were not significant predictors for esp fm or esp fs/fm gene incidence. In summary, the differential occurrence of the esp gene in the environment suggests that it is not limited to human fecal sources and thus may weaken its use as a reliable tool in discriminating contaminant sources (i.e., human vs nonhuman).

Environmental Science & Technology↗
USGS2025

Apicomplexan and non-metazoan microeukaryotes in the thermosensitive reef-building coral Acropora hyacinthus shift in abundance throughout an extreme coral bleaching event

Coral reefs play vital roles in global marine systems and are currently facing increased threats of bleaching. Coral bleaching is heavily influenced by the host-associated microeukaryote community – most notably the dinoflagellate family Symbiodiniaceae. The apicomplexan family Corallicolidae, is the second most abundant member of the microeukaryote community, yet their role in coral health is largely unknown. To explore the role that this apicomplexan and the greater non-metazoan microeukaryotic community play in coral health, samples of a thermally sensitive scleractinian coral, Acropora hyacinthus , were collected over the course of a severe coral bleaching event and its aftermath. Through 18S rRNA gene sequencing analysis, we found that taxa within the family Corallicolidae were relatively enriched in corals during, and immediately after, the severe bleaching event as compared to before or one year after. Although utilizing 18S rRNA gene sequencing methods is not the standard for Symbiodiniaceae community profiling, we were able to observe symbiont shuffling among the Symbiodiniaceae communities, as the dominant algal symbiont shifted from the genus Cladocopium to the genus Symbiodinium following the bleaching event. Furthermore, the non-metazoan microeukaryote community displayed a general shift towards a state of dysbiosis; evidenced by substantial changes in both microeukaryote community composition and dispersion. These results offer insight into the dynamics of apicomplexans throughout the course of an increasingly common global coral reef stressor.

Mo’orea↗
USGS2000

Identification of a basaltic component on the Martian surface from Thermal Emission Spectrometer data

The Mars Global Surveyor Thermal Emission Spectrometer (TES) instrument collected 4.8×10 6 spectra of Mars during the initial aerobraking and science‐phasing periods of the mission (September 14, 1997, through April 29, 1998). Two previously developed atmosphere‐removal models were applied to data from Cimmeria Terra (25°S, 213°W). The surface spectra derived for these two models agree well, indicating that the surface and atmosphere emission can be separated and that the exact atmosphere‐removal model used has little effect on the derived surface composition. The Cimmeria spectra do not match terrestrial high‐silica igneous rocks (granite and rhyolite), ultramafic igneous rocks, limestone, or quartz‐ and clay‐rich sandstone and siltstone. A particulate (sand‐sized) sample of terrestrial flood basalt does provide an excellent match in both spectral shape and band depth to the Cimmeria spectrum over the entire TES spectral range. No unusual particle size effects are required to account for the observed spectral shape and depth. The implied grain size is consistent with the thermal inertia and albedo of this region, which indicate a sand‐sized surface with little dust. The identification of basalt is consistent with previous indications of pyroxene and basalt‐like compositions from visible/near‐infrared and thermal‐infrared spectral measurements. A linear spectral deconvolution model was applied to both surface‐only Cimmeria spectra using a library of 60 minerals to determine the composition and abundance of the component minerals. Plagioclase feldspar (45%; 53%) and clinopyroxene (26%; 19%) were positively identified above an estimated detection threshold of 10–15% for these minerals. The TES observations provide the first identification of feldspars on Mars. The best fit to the Mars data includes only clinopyroxene compositions; no orthopyroxene compositions are required to match the Cimmeria spectra. Olivine (12%; 12%) and sheet silicate (15%; 11%) were identified with lower confidence. Carbonates, quartz, and sulfates were not identified in Cimmeria at detection limits of ∼5, 5, and 10%, respectively. Their presence elsewhere, however, remains open. The Cimmeria spectra are not well matched by any one SNC meteorite spectrum, indicating that this region is not characterized by a single SNC lithology. The occurrence of unweathered feldspar and pyroxene in Cimmeria, together with the inferred presence of pyroxene and unweathered basalts in other dark regions and at the Viking and Pathfinder landing sites, provides evidence that extensive global chemical weathering of materials currently exposed on the Martian surface has not occurred.

Journal of Geophysical Research: Planets↗
USGS2010

The lack of potassium-isotopic fractionation in Bishunpur chondrules

In a search for evidence of evaporation during chondrule formation, the mesostases of 11 Bishunpur chondrules and melt inclusions in olivine phenocrysts in 7 of them have been analyzed for their alkali element abundances and K-isotopic compositions. Except for six points, all areas of the chondrules that were analyzed had δ 41 K compositions that were normal within error (typically ±3%, 2s̀). The six “anomalous” points are probably all artifacts. Experiments have shown that free evaporation of K leads to large 41 K enrichments in the evaporation residues, consistent with Rayleigh fractionation. Under Rayleigh conditions, a 3% enrichment in δ 41 K is produced by ∼12% loss of K. The range of L-chondrite-normalized K/Al ratios (a measure of the K-elemental fractionation) in the areas analyzed vary by almost three orders of magnitude. If all chondrules started out with L-chondrite-like K abundances and the K loss occurred via Rayleigh fractionation, the most K-depleted chondrules would have had compositions of up to δ 41 K ≅ 200%. Clearly, K fractionation did not occur by evaporation under Rayleigh conditions. Yet experiments and modeling indicate that K should have been lost during chondrule formation under currently accepted formation conditions (peak temperature, cooling rate, etc.). Invoking precursors with variable alkali abundances to produce the range of K/Al fractionation in chondrules does not explain the K-isotopic data because any K that was present should still have experienced sufficient loss during melting for there to have been a measurable isotopic fractionation. If K loss and isotopic fractionation was inevitable during chondrule formation, the absence of K-isotopic fractionation in Bishunpur chondrules requires that they exchanged K with an isotopically normal reservoir during or after formation. There is evidence for alkali exchange between chondrules and rim-matrix in all unequilibrated ordinary chondrites. However, melt inclusions can have alkali abundances that are much lower than the mesostases of the host chondrules, which suggests that they at least remained closed since formation. If it is correct that some or all melt inclusions remained closed since formation, the absence of K-isotopic fractionation in them requires that the K-isotopic exchange took place during chondrule formation, which would probably require gas-chondrule exchange. Potassium evaporated from fine-grained dust and chondrules during chondrule formation may have produced sufficient K-vapor pressure for gas-chondrule isotopic exchange to be complete on the timescales of chondrule formation. Alternatively, our understanding of chondrule formation conditions based on synthesis experiments needs some reevaluation.

Meteoritics and Planetary Science↗
USGS2018

A statement of common ground regarding the role of wildfire in forested landscapes of the western United States

For millennia, wildfires have markedly influenced forests and non-forested landscapes of the western United States (US), and they are increasingly seen as having substantial impacts on society and nature. There is growing concern over what kinds and amounts of fire will achieve desirable outcomes and limit harmful effects on people and nature. Moreover, the increasing complexity surrounding cost and management of wildfires suggests that science should play a more prominent role in informing decisions about the need for fire in nature, and the need for society to adapt to the inevitable occurrence of different kinds and amounts of fire and smoke. Scientists widely view the natural wildfire regime as essential to western US forest ecosystem functioning. However, debates continue over how much low-, moderate-, and high severity fire is “natural” or desirable in these forests. Ongoing disagreement centers on the characteristics and importance of historical proportions and patch size distributions of low-, moderate-, and high-severity fires of dry, moist, and cold forests, and on the ecological consequences of changing fire-patch patterns and relative abundances. Scientists also debate the relative importance of climate and extreme weather versus fuel as drivers of high-severity fire, as well as the effectiveness and value of fuel treatments for reducing risks of undesired fire effects. Climate research shows that we should expect shifting future climates in all ecoregions. These expected changes make it difficult for scientists, land managers, and decision-makers to know the degree to which future forest management should be informed by historical conditions. There also is disagreement about how to make western forests more resilient to future disruptions in both climatic and fire regimes. To complicate matters, areas of scientific agreement -- the “common ground” shared by those in the research community -- are poorly articulated. Thus, the focus of the Fire Research Consensus (FRC) project has been to identify common ground among scientists, and provide a summary that can inform management. Land and fire managers are one audience for this report, as are stakeholders and the interested public. Our analysis, which results from extensive scientific literature reviews and questionnaires sent to western fire scientists and land managers, is summarized in nine key topics: A. Fire history and fire ecology vary with geography. B. Human impacts and management history vary with geography. C. Fire is a keystone process, which occurs in almost all western US forest types. D. Knowledge of historical range of variability (HRV) is useful but does not dictate land management goals. E. Forest structure, composition, and fuels have changed, affecting burn severity and fire extent. F. Climate and fuels both influence current fire sizes and their severities. G. The role of changing climatic conditions is increasingly important. H. Multiple fire ecology and fire history research approaches can be useful for characterizing fire regimes. I. Many existing fire management tools and strategies can be useful moving forward. We found much common ground that will be useful to scientists, managers, citizens, and policy decision-makers. For example, there is wide agreement among scientists that fire is one of the most essential influences on western forests and that more fire is needed on most landscapes, but not all wildfire behavior or extent will do. Fires can produce more positive benefits and fewer negative impacts when they burn with an ecologically appropriate mix and pattern of low, moderate, and high severity. Managers will need assistance and funding to create landscape conditions that favor more desirable fire behavior at broad spatial scales. Note that much societal impact from western wildfires occurs in non-forested landscapes that are not covered in this report, where findings would differ from those reported here for forested landscapes. We summarize additional key points below.

Western United States↗
USGS2011

Flow speed estimated by inverse modeling of sandy sediment deposited by the 29 September 2009 tsunami near Satitoa, east Upolu, Samoa

Sandy deposits from the 29 September 2009 tsunami on the east coast of Upolu, Samoa were investigated to document their characteristics and used to apply an inverse sediment transport model to estimate tsunami flow speed. Sandy deposits 6 to 15 cm thick formed from ~ 25 to ~ 250 m inland. Sedimentary layers in the deposits, that are defined by vertical grain size variation and contacts, are interpreted to have formed during onshore runup of two waves. Deposits at 3 locations (100, 170, and 240 m inland) contained two layers that are predominately normally graded (~ 80%), but contained massive sections (~ 15%) and inversely graded sections (~ 5%) at their bases. About 75% of the total thickness of normally graded intervals exhibits a signature of sediment falling out of suspension at their top. This type of grading, termed suspension grading here, was first recognized in turbidity current deposits and is characterized by the entire distribution shifting finer upwards in a layer as high-settling velocity, coarser material deposits first and low-settling velocity finer material deposits last. The Jaffe and Gelfenbaum (2007) inverse sediment transport model was applied to intervals within layers that exhibited suspension grading to estimate tsunami flow speed and was able to reproduce the general trends of the observed suspension grading. A key unknown input in the modeling is the bottom roughness. For a bottom roughness parameterization using a Manning's n of 0.03 (equivalent to a z 0 ~ 0.006 m for the observed flow depths of 2–3 m) flow speeds calculated for the 2 layers at the 3 locations were 3.8, 3.6, and 3.7 m/s (bottom layer/earlier wave) and 4.4, 4.4, and 4.1 m/s (top layer/later wave) at 100, 170, and 240 m inland, respectively. These estimates are consistent with the ~ 3–8 m/s tsunami flow speed from boulder transport calculations and result in Froude numbers of ~ 0.7–1.0 when maximum measured flow depths are used. Because the inverse model assumes the deposit was formed by sediment falling out of suspension care must be taken to model only intervals of the deposit exhibiting suspension grading. Including intervals deposited by either bedload or suspended load transport convergences result in higher, and sometimes unrealistic, tsunami flow speed estimates.

Satitoa, Upolu↗
USGS2003

A Framework for Long-term Ecological Monitoring in Olympic National Park: Prototype for the Coniferous Forest Biome

This report is the result of a five-year collaboration between scientists of the U.S. Geological Survey Forest and Rangeland Ecosystem Science Center, Olympic Field Station, and the natural resources staff of Olympic National Park to develop a comprehensive strategy for monitoring natural resources of Olympic National Park. Olympic National Park is the National Park Serviceʼs prototype monitoring park, representing parks in the coniferous forest biome. Under the umbrella of the National Park Serviceʼs prototype parks program, U.S. Geological Survey and Olympic National Park staffs are obligated to: develop strategies and designs for monitoring the long-term health and integrity of national park ecosystems with a significant coniferous forest component. design exportable monitoring protocols that can be used by other parks within the coniferous forest biome (i.e., parks having similar environments), and create a demonstration area and ʻcenter of excellenceʼ for assisting other parks in developing ecological monitoring programs. Olympic National Park is part of the North Coast and Cascades Network, a network of seven Pacific Northwestern park units created recently by the National Park Serviceʼs Inventory and Monitoring Program to extend the monitoring of ʻvital signsʼ of park health to all National Park Service units. It is our intent and hope that the monitoring strategies and conceptual models described here will meet the overall purpose of the prototype parks monitoring program in proving useful not only to Olympic National Park, but also to parks within the North Coast and Cascades Network and elsewhere. Part I contains the conceptual design and sampling framework for the prototype long-term monitoring program in Olympic National Park. In this section, we explore key elements of monitoring design that help to ensure the spatial, ecological, and temporal integration of monitoring program elements and discuss approaches used to design an ecosystem-based monitoring program. Basic monitoring components include ecosystem drivers, (e.g., climate, atmospheric inputs, human pressures), indicators of ecosystem integrity (e.g., biogeochemical indicators), known threats (e.g., impacts of introduced mountain goats), and focal or ʻkeyʼ species (e.g., rare or listed species, Roosevelt elk). Monitoring system drivers and key indicators of ecosystem integrity provide the long-term baseline needed to judge what constitutes ʻunnaturalʼ variation in park resources and provide the earliest possible warning of unacceptable change. Monitoring effects of known threats and the status of focal species will provide information useful to park managers for dealing with current park issues. In Part I we describe the process of identifying potential indicators of ecological condition and present conceptual models of park ecosystems. In addition we report results from several workshops held in conjunction with Olympic National Park aimed at identifying potential indicators of change in the parkʼs ecosystem. First, we describe the responses of Olympic National Park staff to the generic question, “What is the most important resource to monitor in Olympic National Park and why?” followed by the responses from resource and land managers from areas adjoining the park. We also catalogue the responses of various expert groups that we asked to help identify the most appropriate system drivers and indicators of change in the Olympic National Park ecosystems. Results of the workshops provided the justification for selecting basic indicators of ecosystem integrity, effects of current threats to park resources, and focal resources of parks to detect both the currently evident and unforeseeable changes in park resources. We conclude Part I by exploring several generic statistical issues relevant to monitoring natural resources in Olympic National Park. Specifically we discuss trade-offs associated with sampling extensively versus sampling intensively in smaller geographic regions and describe a conceptual framework to guide development of a generic sampling frame for monitoring. We recommend partitioning Olympic National Park into three zones of decreasing accessibility to maximize monitoring efficiency. We present examples of how the generic sampling frame could be used to help ensure spatial integration of individual monitoring projects. Part II of the report is a record of the potential monitoring questions and indicators identified to date in our workshops. The presentation is organized according to the major system drivers, components, and processes identified in the intermediate-level working model of the Olympic National Park ecosystem. For each component of the park system, we develop the need and justification for monitoring, articulate park management issues, and describe key resources and ecosystem functions. We also present a pictorial conceptual model of each ecological subsystem, identify monitoring questions, and list potential indicators for each monitoring question. We conclude each section by identifying linkages of indicators to other ecological subsystems in our general ecosystem model, spatial and temporal contexts for monitoring (where and how often to monitor), and research and development needs. Part II represents the most current detailed listing of potential indicators—the material for subsequent discussions of monitoring priorities and selection of indicators for protocol development. Collectively, the sections of this report contain a comprehensive list of the important monitoring questions and potential indicators as well as recommendations for designing an integrated monitoring program. In Part I, Chapter 6 we provide recommendations on how to proceed with the important next steps in the design process: establishing priorities among the many possible monitoring questions and indicators, and beginning to research and design effective long-term monitoring protocols.

Information and Technology Report↗
USGS2014

Forecasting landscape effects of Mississippi River diversions on elevation and accretion in Louisiana deltaic wetlands under future environmental uncertainty scenarios

Large sediment diversions are proposed and expected to build new wetlands to alleviate the extensive wetland loss (5,000 km 2 ) affecting coastal Louisiana during the last 78 years. Current assessment and prediction of the impacts of sediment diversions have focused on the capture and dispersal of both water and sediment on the adjacent river side and the immediate outfall marsh area. However, little is known about the effects of sediment diversions on existing wetland surface elevation and vertical accretion dynamics in the receiving basin at the landscape scale. In this study, we used a spatial wetland surface elevation model developed in support of Louisiana's 2012 Coastal Master Plan to examine such landscape-scale effects of sediment diversions. Multiple sediment diversion projects were incorporated in the model to simulate surface elevation and vertical accretion for the next 50 years (2010-2060) under two environmental (moderate and less optimistic) scenarios. Specifically, we examined landscape-scale surface elevation and vertical accretion trends under diversions with different geographical locations, diverted discharge rates, and geomorphic characteristics of the receiving basin. Model results indicate that small diversions (< 283 m 3 s -1 ) tend to have limited effects of reducing landscape-scale elevation loss (< 3%) compared to a future without action (FWOA) condition. Large sediment diversions (> 1,500 m 3 s -1 ) are required to achieve landscape-level benefits to promote surface elevation via vertical accretion to keep pace with rising sea level.

Estuarine, Coastal and Shelf Science↗
USGS2012

Developing a broader scientific foundation for river restoration: Columbia River food webs

Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining associated aquatic and terrestrial communities. The current emphasis on restoring habitat structure—without explicitly considering food webs—has been less successful than hoped in terms of enhancing the status of targeted species and often overlooks important constraints on ecologically effective restoration. We identify three priority food web-related issues that potentially impede successful river restoration: uncertainty about habitat carrying capacity, proliferation of chemicals and contaminants, and emergence of hybrid food webs containing a mixture of native and invasive species. Additionally, there is the need to place these food web considerations in a broad temporal and spatial framework by understanding the consequences of altered nutrient, organic matter (energy), water, and thermal sources and flows, reconnecting critical habitats and their food webs, and restoring for changing environments. As an illustration, we discuss how the Columbia River Basin, site of one of the largest aquatic/riparian restoration programs in the United States, would benefit from implementing a food web perspective. A food web perspective for the Columbia River would complement ongoing approaches and enhance the ability to meet the vision and legal obligations of the US Endangered Species Act, the Northwest Power Act (Fish and Wildlife Program), and federal treaties with Northwest Indian Tribes while meeting fundamental needs for improved river management.

Proceedings of the National Academy of Sciences of↗