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At least 901 records · Page 50Linked to original sources
USGS2000

Effects of climate variability and human activities on Chesapeake Bay and the implications for ecosystem restoration

Chesapeake Bay, the Nation’s largest and most productive estuary (fig. 1), faces complex environmental issues related to nutrients and oxygen, turbidity and sedimentation, toxic dinoflagellates, sea-level rise, and coastal erosion. The Chesapeake Bay Program (CBP) is a partnership among the Chesapeake Bay Commission, the Federal Government, the District of Columbia, and the States of Maryland, Virginia, and Pennsylvania. The CBP is working to preserve, restore, and protect the bay’s living resources, vital habitats, and water quality, to protect human health, and to promote sound land-use policies in the watershed. The CBP began to set restoration goals for the ecosystem in the mid-1980’s and is now refining current goals and setting new ones as part of a new bay agreement— Chesapeake 2000. As the CBP sets restoration goals for the next 10–20 years, it will be critical to understand the long-term changes of the bay ecosystem due to climate variability and the influence of past and future human activities. For the past 4 years, the U.S. Geological Survey (USGS) has been engaged in research designed to provide objective scientific answers to questions about long-term changes in the bay ecosystem: What paleoecological and geochemical methods are best for documenting trends in the bay ecosystem? How does climate variability, including drought, affect the bay? What are historical trends in dissolved oxygen? What is the relationship between sedimentation and water clarity, and what is the effect of turbidity on living resources? How have past land-use changes affected bay habitats and living resources?

Chesapeake Bay Watershed↗
USGS2008

Land area change in coastal Louisiana: A multidecadal perspective (from 1956 to 2006)

The U.S. Geological Survey (USGS) analyzed changes in the configuration of land and water in coastal Louisiana by using a sequential series of 14 data sets summarizing land and water areas from 1956 to 2006. The purpose of this study is to provide a spatially and temporally consistent source of quantitative information on land area across coastal Louisiana, broken into three physiographic provinces (the term 'coastal Louisiana' is used to present data on the collective area). The land-water data sets used in this study are interpreted through spatial analysis and by linear regression analysis. The spatial depictions of land area change reveal a complex and interwoven mosaic of loss and gain patterns caused by natural and human-induced processes operating at varied temporal and spatial scales, resulting in fluctuating contributions to coastal loss. The linear regression analysis provides a robust estimate of recent change trends by comparing land area over time for all data sets from 1985 to 2004 and from 1985 to 2006 by physiographic province across coastal Louisiana. The 1956 to 2006 map showing multidecadal changes, along with the linear regressions of land area change presented in this study, provide a comprehensive and concise presentation of historical trends and rates of land area change in coastal Louisiana. Taking a broad historical view provides an in-depth understanding of land area changes over time. For example, one observation provided by our historical review is that the majority of the widespread, nontransitory land gains depicted on the map over the past 50 years, with the exception of the progradation of the Atchafafalaya River and Wax Lake deltas, are primarily related to sediment placement and landward migration of barrier islands. Another point revealed by our historical approach is that recent land losses caused by hurricanes sometimes commingled with or exacerbated older losses formed during the 1956 to 1978 period. Furthermore, our analyses also show how the immediate impacts of extreme storms can alter the long-term, time-averaged trends of landscape change, thus limiting the range of projections for the future. For this reason, this study does not include trend projections beyond 2015 because of uncertainties related to recovery from the 2005 hurricane season and the potential for other episodic events that could skew future rates of change.

Louisiana↗
USGS2012

Seasonal variability in the surface sediments of Mobile Bay, Alabama, recorded by geochemistry and foraminifera, 2009–2010

A study was undertaken in order to document and quantify recent environmental change in Mobile Bay, Alabama. The study was part of the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazard Susceptibility project, a regional project funded by the Coastal and Marine Geology Program to understand how natural forcings and anthropogenic modifications influence coastal ecosystems and their susceptibility to coastal hazards. Mobile Bay is a large drowned-river estuary that has been modified significantly by humans to accommodate the Port of Mobile. Examples include repeated dredging of a large shipping channel down the central axis of the bay and construction of a causeway across the head of the bay and at the foot of the bayhead delta. In addition to modifications, the bay is also known to have episodic periods of low oxygen (hypoxia) that result in significant mortality to fish and benthic organisms (May, 1973). For this study a series of surface sediment samples were collected. Surface benthic foraminiferal and bulk geochemical data provide the modern baseline conditions of the bay and can be used as a reference to changing environmental parameters in the past (Osterman and Smith, in press) and into the future. This report archives data collected as part of the Mobile Bay Study that may be used in future environmental change studies.

Alabama↗
USGS2025

Beak deformities in Buteo jamaicensis (Red-tailed Hawk) signal possible emergence of avian keratin disorder among raptors

Beginning in the late 1990s, an unusual cluster of beak deformities was observed among Buteo jamaicensis (Red-tailed Hawk) in the Pacific coastal region of North America. However, information was not available to determine the scope of this problem nor to assess a potential link between beak deformities in hawks and avian keratin disorder (AKD), an emerging disease primarily among passerines that causes overgrowth of the keratinized layer of the beak. To help address these knowledge gaps, we compiled capture records, citizen science reports, and other available data from across North America. As part of a long-term raptor monitoring program in Washington, we detected anomalously high rates of beak deformities in 29% and other keratin abnormalities in an additional 19% of B. jamaicensis between 2014 and 2021. We also identified more than 100 other AKD-like cases in B. jamaicensis , largely clustered in the Pacific coastal region, with most reports from 2000 to present. Pathologic examination of affected hawks revealed gross and microscopic features consistent with AKD in passerines, while shared epidemiological patterns, including timing of emergence, provided further evidence that this disease may impact an ecologically diverse suite of species. We detected poecivirus, a novel avian virus implicated as a likely cause of AKD in Poecile atricapillus (Black-capped Chickadee), in 1 out of 10 swabs collected from live B. jamaicensis , with gross beak deformities, suggesting the possibility of a shared viral etiology across species. However, additional work would be needed to determine the underlying cause of beak deformities in and their potential impacts on B. jamaicensis . By documenting this cluster of beak deformities, we hope to raise awareness among the ornithological community, including raptor researchers, to better track current and future outbreaks of beak deformities and related conditions.

Ornithology↗
USGS2014

Studying seafloor bedforms using autonomous stationary imaging and profiling sonars

The Sediment Transport Group at the U.S. Geological Survey, Woods Hole Coastal and Marine Science Center uses downward looking sonars deployed on seafloor tripods to assess and measure the formation and migration of bedforms. The sonars have been used in three resolution-testing experiments, and deployed autonomously to observe changes in the seafloor for up to two months in seven field experiments since 2002. The sonar data are recorded concurrently with measurements of waves and currents to: a) relate bedform geometry to sediment and flow characteristics; b) assess hydrodynamic drag caused by bedforms; and c) estimate bedform sediment transport rates, all with the goal of evaluating and improving numerical models of these processes. Our hardware, data processing methods, and test and validation procedures have evolved since 2001. We now employ a standard sonar configuration that provides reliable data for correlating flow conditions with bedform morphology. Plans for the future are to sample more rapidly and improve the precision of our tripod orientation measurements.

Conference Paper↗
USGS2008

Wind, waves, and wing loading: Morphological specialization may limit range expansion of endangered albatrosses

Among the varied adaptations for avian flight, the morphological traits allowing large-bodied albatrosses to capitalize on wind and wave energy for efficient long-distance flight are unparalleled. Consequently, the biogeographic distribution of most albatrosses is limited to the windiest oceanic regions on earth; however, exceptions exist. Species breeding in the North and Central Pacific Ocean (Phoebastria spp.) inhabit regions of lower wind speed and wave height than southern hemisphere genera, and have large intrageneric variation in body size and aerodynamic performance. Here, we test the hypothesis that regional wind and wave regimes explain observed differences in Phoebastria albatross morphology and we compare their aerodynamic performance to representatives from the other three genera of this globally distributed avian family. In the North and Central Pacific, two species (short-tailed P. albatrus and waved P. irrorata) are markedly larger, yet have the smallest breeding ranges near highly productive coastal upwelling systems. Short-tailed albatrosses, however, have 60% higher wing loading (weight per area of lift) compared to waved albatrosses. Indeed, calculated aerodynamic performance of waved albatrosses, the only tropical albatross species, is more similar to those of their smaller congeners (black-footed P. nigripes and Laysan P. immutabilis), which have relatively low wing loading and much larger foraging ranges that include central oceanic gyres of relatively low productivity. Globally, the aerodynamic performance of short-tailed and waved albatrosses are most anomalous for their body sizes, yet consistent with wind regimes within their breeding season foraging ranges. Our results are the first to integrate global wind and wave patterns with albatross aerodynamics, thereby identifying morphological specialization that may explain limited breeding ranges of two endangered albatross species. These results are further relevant to understanding past and potentially predicting future distributional limits of albatrosses globally, particularly with respect to climate change effects on basin-scale and regional wind fields.

PLoS ONE↗
USGS2011

Vegetation of the Elwha River estuary: Chapter 8 in Coastal habitats of the Elwha River, Washington--biological and physical patterns and processes prior to dam removal

The Elwha River estuary supports one of the most diverse coastal wetland complexes yet described in the Salish Sea region, in terms of vegetation types and plant species richness. Using a combination of aerial imagery and vegetation plot sampling, we identified 6 primary vegetation types and 121 plant species in a 39.7 ha area. Most of the estuary is dominated by woody vegetation types, with mixed riparian forest being the most abundant (20 ha), followed by riparian shrub (6.3 ha) and willow-alder forest (3.9 ha). The shrub-emergent marsh transition vegetation type was fourth most abundant (2.2 ha), followed by minor amounts of dunegrass (1.75 ha) and emergent marsh (0.2 ha). This chapter documents the abundance, distribution, and floristics of these six vegetation types, including plant species richness, life form, species origin (native or introduced), and species wetland indicator status. These data will serve as a baseline to which future changes can be compared, following the impending removal of Glines Canyon and Elwha Dams upstream on the Elwha River. Dam removals may alter many of the processes, materials, and biotic interactions that influence the estuary plant communities, including hydrology, salinity, sediment and wood transport, nutrients, and plant-microbe interactions.

Washington↗
USGS2023

Decline in small mammal species richness in coastal-central California, 1997–2013

The richness and composition of a small mammal community inhabiting semiarid California oak woodland may be changing in response to climate change, but we know little about the causes or consequence of these changes. We applied a capture-mark-recapture model to 17 years (1997–2013) of live trapping data to estimate species-specific abundances. The big-eared woodrat was the most frequently captured species in the area, contributing 58% of total captures. All small mammal populations exhibited seasonal fluctuations, whereas those of the California mouse, brush mouse, and pinyon mouse declined during the study period. We also applied a multispecies dynamic occupancy model to our small mammal detection history data to estimate species richness, occupancy ( ), detection (p), local extinction ( ), and colonization ( ) probabilities, and to discern factors affecting these parameters. We found that decreased from 0.369 ± 0.088 in 1997 to 0.248 ± 0.054 in 2013; was lower during the dry season (May–September) than the wet season (October–April) and was positively influenced by total seasonal rainfall (slope parameter, = 0.859 ± 0.371; 95% CI = 0.132–1.587). Mean mammalian species richness decreased from 11.943 ± 0.461 in 1997 to 7.185 ± 0.425 in 2013. With highly variable climatic patterns expected in the future, especially increased frequency and intensity of droughts, it is important to monitor small mammal communities inhabiting threatened California oak woodlands.

California↗
USGS2006

Applicability of terrestrial LIDAR scanning for scientific studies in Grand Canyon National Park, Arizona

In November 2004, an experimental high flow release of water from Glen Canyon Dam into the Colorado River through Grand Canyon National Park in Arizona was conducted. The goal of the experiment was to evaluate the use of high flow events as a management tool for the preservation and restoration of natural resources in the Colorado River below Glen Canyon Dam. The U.S. Geological Survey (USGS), Grand Canyon Monitoring and Research Center (GCMRC) located in Flagstaff, Arizona performed oversight of all aspects of scientific data collection including suspended sediment transport studies, biological population variations, effects on archaeological resources, and morphological studies of river sand bars. As part of the experimental high flow studies, the USGS Coastal and Marine Geology (CMG) team was invited to participate to test the effectiveness of utilizing terrestrial LIDAR technology for gathering morphological data on sand bars, biological habitats, and archaeological sites. The CMG is equipped with a terrestrial LIDAR unit and has used the technique in a variety of terrains to gather high-resolution morphological data. A three-member team from CMG participated in the experiment, joining a GCMRC team on a river trip from November 18 to November 21, 2004. This report begins with a brief description of the LIDAR technique and then outlines the data collected, processing required, and results for three study areas located within the Grand Canyon. Specifically, studies were performed at the Mile 30 Sand Bar, at Vaseys Paradise (Mile 32), and at the Mile 66 Palisades Archaeological Site. Conclusions and recommendations for utilizing terrestrial LIDAR for future studies at each of these sites are also included.

Arizona↗
USGS2021

Translational science education through citizen science

Guided by the six elements of Translational Ecology (TE; i.e., decision-framing, collaboration, engagement, commitment, process, and communication), we showcase the first explicit example of a Translational Science Education (TSE) effort in the coastal redwood ecosystem of Humboldt County, CA. Using iNaturalist, a flexible and free citizen science/crowdsourcing app, we worked with students from grade school through college, and their teachers and community, to generate species lists for comparison among 19 school and non-profit locations spanning a range of urbanization. Importantly, this TSE effort resulted in both learning and data generation, highlighting the ability of a TSE framework to connect and benefit both students and researchers. Our data showed that, regardless of the age of the observers, holding organized BioBlitzes added substantially more species to local biodiversity lists than would have been generated without them. In support of current ecological theory, these data showed an urbanization gradient among sites, with rural sites containing fewer non-native species than urban ones. On the education side, qualitative assessments revealed students and educators remained engaged throughout the project. Future projects would also benefit by establishing quantifiable metrics for assessing student learning from project conception. Throughout the project, the fundamentals of TE were followed with repeated interactions and shared objectives developed over time within trusted community relationships. Such positive human interactions can lead new naturalists to think of themselves as champions of their local biodiversity (i.e., as land stewards). We anticipate that such newly empowered and locally expert naturalists will remain committed to land stewardship in perpetuity and that other scientists and educators are inspired to conduct similar work.

California↗
USGS2014

Marine fog: a review

The objective of this review is to discuss physical processes over a wide range of spatial scales that govern the formation, evolution, and dissipation of marine fog. We consider marine fog as the collective combination of fog over the open sea along with coastal sea fog and coastal land fog. The review includes a history of sea fog research, field programs, forecasting methods, and detection of sea fog via satellite observations where similarity in radiative properties of fog top and the underlying sea induce further complexity. The main thrust of the study is to provide insight into causality of fog including its initiation, maintenance, and destruction. The interplay between the various physical processes behind the several stages of marine fog is among the most challenging aspects of the problem. An effort is made to identify this interplay between processes that include the microphysics of fog formation and maintenance, the influence of large-scale circulation and precipitation/clouds, radiation, turbulence (air-sea interaction), and advection. The environmental impact of marine fog is also addressed. The study concludes with an assessment of our current knowledge of the phenomenon, our principal areas of ignorance, and future lines of research that hold promise for advances in our understanding.

Atmospheric Research↗
USGS1975

Water and the South Florida environment

Ecological problems are a major concern to Florida as well as to the Nation. National attention was focused on these problems in September 1968, when the Port Authority of Dade County began to con- struct a jetport for supersonic aircraft on a 39-square-mile tract 6 miles north of Everglades National Park and on the east edge of the Big Cypress Swamp. Conservation groups and citizens raised questions as to the effects of a regional jetport and the attendant satellite growth on the water resources and biological communities of the National Park. The Department of the Interior began studies to investigate the situation. One study, Leopold (1969), reported on the unfavorable ecological effects of the attendant satellite growth. Then Secretary of the Interior, Walter J. Hickel, directed the U.S. Geological Survey to study the water resources of the Big Cypress to determine which parts of the Big Cypress contribute the major part of the water necessary to maintain adequate water supplies for Everglades National Park. This was done in a report by Klein and others (1970). At about the same time, the Departments of interior and Transportation, the State of Florida, and the Dade County Port Authority con-curred in assigning to the Secretary of the Interior certain responsibilities for planning, developing, and coordinating an ecological study of south Florida. A primary objective of the ecological study is to provide information that will assist in the formulation of land-use policy consistent with the protection of the environment of Everglades National Park, the adjacent estuaries, and the public water supplies. The part of the investigation describing the surface-water and ground-water resources of south Florida was assigned to the Geological Survey. The quantity and quality of surface water and ground water and their interrelation with estuarine and marine waters are here considered. Also considered are the problems, present or future, related to the hydrologic environment that involve human, animal, and plant life. Changes taking place, apparent trends, and projections for the future are also considered, as well as alternatives for water management. The Geological Survey effort began in January 1971, when aerial photography and selected qualitative hydrologic data were obtained. However, most of the information upon which this report Is based was obtained by the Geological Survey in cooperative programs with several local, State, and Federal agencies since about 1940. The long-term support of the U.S. Army Corps of Engineers, the National Park Service, U.S. Navy, Florida Department of Natural Resources, Central and Southern Florida Flood Control District, Dade, Broward, Palm Beach and Collier Counties, Miami and Miami Beach, Ft. Lauderdale, Naples and others in the collection of data is gratefully acknowledged. A prolonged drought throughout south Florida from September 1970 to May 1971 accentuated the importance and timeliness of the study. The drought brought about a readvance of sea-water intrusion in many coastal areas, which necessitated restrictions on water use. The effect of drought on the regional water supply, continued population growth and increased water demands, and deterioration of the water quality in many of the canals and waterways of the urban areas accentuated the need for improved water management and land-use planning. As a result of the water crisis, the Governor of Florida called a special conference in September 1971. The conference, attended by foremost scientific and government personnel, proposed creation of an agency that would develop and implement comprehensive land and water-use plans for south Florida that would minimize environmental degradation.

Florida↗
USGS2022

Round Goby captured in a North American estuary: Status and implications in the Hudson River, New York

Round Goby Neogobius melanostomus , a nonnative fish species to North America, has been rapidly expanding through the connected waterways of the Laurentian Great Lakes. Herein, we document the eastward and southern expansion of Round Goby into the Hudson River, New York, an iconic coastal estuary that drains to Long Island Sound and the Atlantic seaboard. In summer and early fall 2021, routine fish monitoring conducted by the New York State Department of Environmental Conservation documented a population of Round Goby in the tidal portion of the Hudson River. Over the course of monitoring in 2021, personnel collected 112 Round Goby between Albany, New York, and Poughkeepsie, New York, with the southernmost collection occurring approximately 140 km downstream of invasion front as reported in 2020 within the New York State Canal System. Although Round Goby previously colonized large rivers and streams in the Great Lakes watershed, there is little information about the invasion success and ecological impacts of Round Goby in estuarine environments in North America. We discuss the distribution and biological characteristics of the Hudson River Round Goby population as well as the potential ecological implications and areas of future research and monitoring for this range expansion.

New York↗
USGS2011

Trends in marine debris in the U.S. Caribbean and the Gulf of Mexico, 1996-2003

Marine debris is a widespread and globally recognized problem. Sound information is necessary to understand the extent of the problem and to inform resource managers and policy makers about potential mitigation strategies. Although there are many short-term studies on marine debris, a longer-term perspective and the ability to compare among regions has heretofore been missing in the U.S. Caribbean and the Gulf of Mexico. We used data from a national beach monitoring program to evaluate and compare amounts, composition, and trends of indicator marine debris in the U.S. Caribbean (Puerto Rico and the U.S. Virgin Islands) and the Gulf of Mexico from 1996 to 2003. Indicator items provided a standardized set that all surveys collected; each was assigned a probable source: ocean-based, land-based, or general-source. Probable ocean-based debris was related to activities such as recreational boating/fishing, commercial fishing and activities on oil/gas platforms. Probable land-based debris was related to land-based recreation and sewer systems. General-source debris represented plastic items that can come from either ocean- or land-based sources; these items were plastic bags, strapping bands, and plastic bottles (excluding motor oil containers). Debris loads were similar between the U.S. Caribbean and the western Gulf of Mexico; however, debris composition on U.S. Caribbean beaches was dominated by land-based indicators while the western Gulf of Mexico was dominated by ocean-based indicators. Beaches along the eastern Gulf of Mexico had the lowest counts of debris; composition was dominated by land-based indicators, similar to that found for the U.S. Caribbean. Debris loads on beaches in the Gulf of Mexico are likely affected by Gulf circulation patterns, reducing loads in the eastern Gulf and increasing loads in the western Gulf. Over the seven years of monitoring, we found a large linear decrease in total indicator debris, as well as all source categories, for the U.S. Caribbean. Lower magnitude decreases were seen in indicator debris along the eastern Gulf of Mexico. In contrast, only land-based indicators declined in the western Gulf of Mexico; total, ocean-based and general-source indicators remained unchanged. Decreases in land-based indicators were not related to human population in the coastal regions; human population increased in all regions over the time of the study. Significant monthly patterns for indicator debris were found only in the Gulf of Mexico; counts were highest during May through September, with peaks occurring in July. Inclement weather conditions before the time of the survey also accounted for some of the variation in the western Gulf of Mexico; fewer items were found when there were heavy seas or cold fronts in the weeks prior to the survey, while tropical storms (including hurricanes) increased the amount of debris. With the development around the globe of long-term monitoring programs using standardized methodology, there is the potential to help management at individual sites, as well as generate larger-scale perspectives (from regional to global) to inform decision makers. Incorporating mechanisms producing debris into marine debris programs would be a fruitful area for future research.

Gulf of Mexico and U.S. Carribean↗
USGS2021

Satellite-derived barrier response and recovery following natural and anthropogenic perturbations, northern Chandeleur Islands, Louisiana

The magnitude and frequency of storm events, relative sea-level rise (RSLR), sediment supply, and anthropogenic alterations drive the morphologic evolution of barrier island systems, although the relative importance of any one driver will vary with the spatial and temporal scales considered. To explore the relative contributions of storms and human alterations to sediment supply on de-cadal changes in barrier landscapes, we applied Otsu’s thresholding method to multiple satel-lite-derived spectral indices for coastal land-cover classification and analyzed Landsat satellite imagery to quantify changes to the northern Chandeleur Islands barrier system since 1984. This high temporal-resolution dataset shows decadal-scale land-cover oscillations related to storm–recovery cycles, suggesting that shorter and (or) less resolved time series are biased toward storm impacts and may significantly overpredict land-loss rates and the timing of barrier mor-phologic state changes. We demonstrate that, historically, vegetation extent and persistence were the dominant controls on alongshore-variable landscape response and recovery following storms, and are even more important than human-mediated sediment input. As a result of exten-sive vegetation losses over the past few decades, however, the northern Chandeleur Islands are transitioning to a new morphologic state in which the landscape is dominated by intertidal envi-ronments, indicating reduced resilience to future storms and possibly rapid transitions in mor-phologic state with increasing rates of RSLR.

Louisiana↗
USGS2013

U.S. Department of the Interior South Central Climate Science Center strategic science plan, 2013--18

The Department of the Interior (DOI) recognizes and embraces the unprecedented challenges of maintaining our Nation’s rich natural and cultural resources in the 21st century. The magnitude of these challenges demands that the conservation community work together to develop integrated adaptation and mitigation strategies that collectively address the impacts of climate change and other landscape-scale stressors. On September 14, 2009, DOI Secretary Ken Salazar signed Secretarial Order 3289 (amended February 22, 2010) entitled, “Addressing the Impacts of Climate Change on America’s Water, Land, and Other Natural and Cultural Resources.” The Order establishes the foundation for two partner-based conservation science entities to address these unprecedented challenges: Climate Science Centers (CSCs and Landscape Conservation Cooperatives (LCCs). CSCs and LCCs are the Department-wide approach for applying scientific tools to increase understanding of climate change and to coordinate an effective response to its impacts on tribes and the land, water, ocean, fish and wildlife, and cultural-heritage resources that DOI manages. Eight CSCs have been established and are managed through the U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center (NCCWSC); each CSC works in close collaboration with their neighboring CSCs, as well as those across the Nation, to ensure the best and most efficient science is produced. The South Central CSC was established in 2012 through a cooperative agreement with the University of Oklahoma, Texas Tech University, Louisiana State University, the Chickasaw Nation, the Choctaw Nation of Oklahoma, Oklahoma State University, and NOAA’s Geophysical Fluid Dynamics Lab; hereafter termed the ”Consortium” of the South Central CSC. The Consortium has a broad expertise in the physical, biological, natural, and social sciences to address impacts of climate change on land, water, fish and wildlife, ocean, coastal, and cultural resources. The South Central CSC will provide scientific information, tools, and techniques that managers and other parties interested in land, water, wildlife, and cultural resources can use to anticipate, monitor, and adapt to climate change, actively engaging LCCs and other partners in translating science into management decisions. This document is the first Strategic Science Plan for the South Central CSC (2013-18). Using the January 2011 DOI guidance as a model, this document (1) describes the role and interactions of the South Central CSC among partners and stakeholders including Federal, State, and non-governmental organizations throughout the region; (2) describes a concept of what the center will provide to its partners; (3) defines a context for climate impacts in the south central United States; and (4) establishes the science priorities the center will address through research. Science priorities are currently organized as immediate or future research needs; however, this document is intended to be reevaluated and modified as partner needs change and as scientific work progresses.

Open-File Report↗
USGS2011

Mountain Glaciers and Ice Caps

In addition to the Greenland Ice Sheet, the Arctic contains a diverse array of smaller glaciers ranging from small cirque glaciers to large ice caps with areas up to 20 000 km 2 . Together, these glaciers cover an area of more than 400 000 km 2 , over half the global area of mountain glaciers and ice caps. Their total volume is sufficient to raise global sea level by an average of about 0.41 m if they were to melt completely. These glaciers exist in a range of different climatic regimes, from the maritime environments of southern Alaska, Iceland, western Scandinavia, and Svalbard, to the polar desert of the Canadian Arctic. Glaciers in all regions of the Arctic have decreased in area and mass as a result of the warming that has occurred since the 1920s (in two pulses – from the 1920s to the 1940s and since the mid-1980s). A new phase of accelerated mass loss began in the mid-1990s, and has been most marked in Alaska, the Canadian Arctic, and probably Greenland. Current rates of mass loss are estimated to be in the range 150 to 300 Gt/y; comparable to current mass loss rates from the Greenland Ice Sheet. This implies that the Arctic is now the largest regional source of glacier contributions to global sea-level rise. Most of the current mass loss is probably attributable to a change in surface mass balance (the balance between annual mass addition, primarily by snowfall, and annual mass loss by surface melting and meltwater runoff). Iceberg calving is also a significant source of mass loss in areas such as coastal Alaska, Arctic Canada, Svalbard, and the Russian Arctic. However, neither the current rate of calving loss nor its temporal variability have been well quantified in many regions, so this is a significant source of uncertainty in estimates of the total rate of mass loss. It is, however, clear that the larger Arctic ice caps have similar variability in ice dynamics to that of the Greenland Ice Sheet. That is to say, areas of relatively slow glacier flow (which terminate mainly on land) are separated by faster-flowing outlet glaciers (which terminate mainly in the ocean). Several of these outlet glaciers exhibit surge-type behavior, while others have exhibited substantial velocity changes on seasonal and longer timescales. It is very likely that these changes in ice dynamics affect the rate of mass loss by calving both from individual glaciers and the total ice cover. Projections of future rates of mass loss from mountain glaciers and ice caps in the Arctic focus primarily on projections of changes in the surface mass balance. Current models are not yet capable of making realistic forecasts of changes in losses by calving. Surface mass balance models are forced with downscaled output from climate models driven by forcing scenarios that make assumptions about the future rate of growth of atmospheric greenhouse gas concentrations. Thus, mass loss projections vary considerably, depending on the forcing scenario used and the climate model from which climate projections are derived. A new study in which a surface mass balance model is driven by output from ten general circulation models (GCMs) forced by the IPCC (Intergovernmental Panel on Climate Change) A1B emissions scenario yields estimates of total mass loss of between 51 and 136 mm sea-level equivalent (SLE) (or 13% to 36% of current glacier volume) by 2100. This implies that there will still be substantial glacier mass in the Arctic in 2100 and that Arctic mountain glaciers and ice caps will continue to influence global sea-level change well into the 22nd century.

Book chapter↗
USGS2023

Above- and belowground biomass carbon stock and net primary productivity maps for tidal herbaceous marshes of the United States

Accurate assessments of greenhouse gas emissions and carbon sequestration in natural ecosystems are necessary to develop climate mitigation strategies. Regional and national-level assessments of carbon sequestration require high-resolution data to be available for large areas, increasing the need for remote sensing products that quantify carbon stocks and fluxes. The Intergovernmental Panel on Climate Change (IPCC) provides guidelines on how to quantify carbon flux using land cover land change and biomass carbon stock information. Net primary productivity (NPP), carbon uptake, and storage in vegetation, can also be used to model net carbon sequestration and net carbon export from an ecosystem (net ecosystem carbon balance). While biomass and NPP map products for terrestrial ecosystems are available, there are currently no conterminous United States (CONUS) biomass carbon stock or NPP maps for tidal herbaceous marshes. In this study, we used peak soil adjusted vegetation index (SAVI) values, derived from Landsat 8 composites, and five other vegetation indices, plus a categorical variable for the CONUS region (Pacific Northwest, California, Northeast, Mid-Atlantic, South Atlantic-Gulf, or Everglades), to model spatially explicit aboveground peak biomass stocks in tidal marshes (i.e., tidal palustrine and estuarine herbaceous marshes) for the first time. Tidal marsh carbon conversion factors, root-to-shoot ratios, and vegetation turnover rates, were compiled from the literature and used to convert peak aboveground biomass to peak total (above- and belowground) biomass and NPP. An extensive literature search for aboveground turnover rates produced sparse and variable values; therefore, we used an informed assumption of a turnover rate of one crop per year for all CONUS tidal marshes. Due to the lack of turnover rate data, the NPP map is identical to the peak biomass carbon stock map. In reality, it is probable that turnover rate varies by region, given seasonal length differences; however, the NPP map provides the best available information on spatially explicit CONUS tidal marsh NPP. This study identifies gaps in the scientific knowledge, to support future studies in addressing this lack of turnover data. Across CONUS, average total peak biomass carbon stock in tidal marshes was 848 g C m −2 (871 g C m −2 in palustrine and 838 g C m −2 in estuarine marshes), and based on a median biomass turnover rate of 1, it is expected that the mean NPP annual flux for tidal marshes is similar (e.g., 848 g C m −2 y −1 ). Peak biomass carbon stocks in tidal marshes were lowest in the Florida Everglades region and highest in the California regions. These are the first fine-scale national maps of biomass carbon and NPP for tidal wetlands, spanning all of CONUS. These estimates of CONUS total peak biomass carbon stocks and NPP rates for tidal marshes can support regional- and national-scale assessments of greenhouse gas emissions, as well as natural resource management of coastal wetlands, as part of nature-based climate solution efforts.

Remote Sensing↗