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At least 451 records · Page 25Linked to original sources

Semi-centennial of Landsat observations and pending Landsat 9 launch

The first Landsat was placed in orbit on 23 July 1972, followed by a series of missions that have provided nearly continuous, two-satellite 8-day repeat image coverage of the Earth’s land areas for the last half-century. These observations have substantially enhanced our understanding of the Earth’s terrestrial dynamics, both as a major element of the Earth’s physical system, the primary home of humans, and the major source of natural resources that support them. The history of Landsat is complex, reflective of the human systems that sustain it. Despite the conflicted perspectives surrounding the continuation of the program, Landsat has survived based on worldwide recognition of its critical contributions to understanding land dynamics, management of natural resources and Earth system science. Launch of Landsat 9 is anticipated in Fall 2021, and current planning for the next generation, Landsat Next is well underway. The community of Landsat data users is looking forward to another 50 years of the Landsat program.

Photogrammetric Engineering and Remote Sensing (PE↗

Hydratools manual version 1.0, documentation for a MATLAB ® -based post-processing package for the Sontek Hydra

The Sediment Transport Instrumentation Group (STG) at the U.S. Geological Survey (USGS) Woods Hole Science Center has a long-standing comitment to providing scientists with high quality oceanographic data. To meet this commitment, STG personnel are vigilant in checking data as well as hardware for signs of instrument malfunction. STG data sets are accompanied by processing histories to detail data processing procedures that may have modified the natural data signal while removing noise from the data. The history also allows the data to be reprocessed in the ligth of new insight into instrument function and moored conditions. This toolbox was compiled to meet these data quality commitments for data generated by Sontek Hydra systems using both ADV and PCADP probes. In the mid 1900's, the USGS Coastal and Marine Program began frequent deployments of Sontek Hydra systems in support of projects in estuaries, coastal, and continental shelf regions nationwide. Hydra data sets are large and complex in structure, and existing processing and editing tools consisted of fragments of MATLAB code written by USGS scientists to satisfy personal research needs. This code did not meet STG quality control criteria. This toolbox permits engineers and scientists to monitor data quality by: 1. processing data with interactive critical review; 2. preserving data quality indicators; 3. preserving minimally processed and partially processed versions of data sets. STG usually deploys ADV and PCADP probes configured as downward looking, mounted on bottom tripods, with the objective of measuring high-resolution near-bed currents. The velocity profiles are recorded with minimal internal data processing. Also recorded are parameters such as temperature, conductivity, optical backscatter, light transmission, and high frequency pressure. Sampling consists of high-frequency bursts(1–10 Hz) bursts of long duration (5–30 minutes) at regular and recurring intervals for a duration of 1 to 6 months. The result is very large data files, often 500 MB per Hydra, per deployment, in Sontek's compressed binary format. This section introduces the Hydratools toolbox and provides information about the history of the system's development. The USGS philosophy regarding data quality is discussed to provide an understating of the motivation for creating the system. General information about the following topics will also be discussed: hardware and software required for the system, basic processing steps, limitations of program usage, and features that are unique to the programs.

Open-File Report↗

Founders of fish culture - European origins

Just where true fish culture appeared in history depends entirely upon what one considers fish culture to be. If the transportation of fishes from regions of plenty to those of few is to be regarded as fish culture - as it is by some even today - then this story should start in remotest antiquity and deal with an amazing series of failures. However, fish culture to be classed as a science must include far more than mere transportation, it must include a deliberate effort on the part of man to master a technique of fish raising which will yield results far superior to Nature's. Accordingly, the wheel of history must be spun forward to the fifteenth century, A. D., when man first conceived the idea that with care and exactitude, he could improve upon Nature. The fish cultural efforts of the Chinese, the Egyptians, the Greeks, and the Romans may be skipped over in a hurry, for they represented little more than the transportation and rearing of wild fish. With the renaissance of modern civilization in Europe came the birth of scientific fish culture.

Progressive Fish-Culturist↗

Anthropogenic nitrogen deposition induces rapid ecological changes in alpine lakes of Colorado Front Range (USA)

Recent sediments from two alpine lakes (> 3300 m asl) in the Colorado Front Range (USA) register marked and near-synchronous changes that are believed to represent ecological responses to enhanced atmospheric deposition of fixed nitrogen from anthropogenic sources. Directional shifts in sediment proxies include greater representations of mesotrophic diatoms and increasingly depleted δ 15 N values. These trends are particularly pronounced since ~ 1950, and appear to chronicle lake responses to excess N derived from agricultural and industrial sources to the east. The rate and magnitude of recent ecological changes far exceed the context of natural variability, as inferred from comparative analyses of a long core capturingthe entire 14,000-year postglacial history of one of the lakes. Nitrogen deposition to these seemingly pristine natural areas has resulted in subtle but detectable limnological changes that likely represent the beginning of a stronger response to nitrogen enrichment.

Journal of Paleolimnology↗

Rocky road in the Rockies: Challenges to biodiversity

To people worldwide, the Rocky Mountains of the United States and Canada represent a last bastion of nature in its purest and rawest form-unspoiled forests teeming with elk and deer stalked by mountain lions and grizzly bears; bald eagles nesting near lakes and rivers; fat, feisty native trout in rushing mountain streams; and dazzling arrays of wildflowers in lush meadows. In fact, the total biodiversity of the Rocky Mountains is considerable, with relatively high diversity in birds, mammals, butterflies, reptiles, and conifers (Ricketts et al. 1999) and with geographic variation in the flora and fauna of alpine, forest, foothill, and adjacent shortgrass prairie and shrub communities over more than 20 degrees of latitude and more than 10' of longitude. Although the biodiversity of most North American regions has declined because of anthropogenic influences, the perception remains that the biodiversity of the Rocky Mountains is intact. This view exists in part because the Rocky Mountains are remote from urban centers, in part because so much of the land comprises protected areas such as national parks and wilderness areas, and in part because of wishful thinking-that nothing bad could happen to the biodiversity that is so much a part of the history, national self-image, legends, nature films, and movies of the United States and Canada. Despite modern technology and the homogenization and globalization of their cities and towns, at heart North Americans still regard their land as the New World, with pristine nature and untamed landscapes epitomized by the Rockies. The reality is that the biodiversity of the Rocky Mountains has not been free of anthropogenic influences since the West was settled in the 1800s, and in fact it was altered by Native Americans for centuries prior to settlement. A number of escalating problems and consequences of management choices are currently changing Rocky Mountain ecological communities at a dizzying pace. In Order to maintain some degree of natural ecosystem processes and preserve natural biodiversity in light of these challenges, Americans and Canadians are faced with the need for intensive, hands-on management of both ecosystems and selected plant and animal populations. In this chapter, we first discuss the primary issues regarding the biodiversity of the Rocky Mountains, including the Rocky Mountain portions of Arizona, Colorado, Idaho, Montana, New Mexico, Utah, Wyoming, British Columbia, and Alberta. Next, we survey groups of organisms to examine their status and special problems. Finally, we touch on major challenges to biodiversity that loom in the near future. Given that entire books may be written on these issues, the discussion is brief and general, but with case histories for more detailed examples.

Book chapter↗

Differences in life history patterns of American shad, Alosa sapidissima, populations between ancestral, Atlantic coast, and non-native, Pacific coast rivers of North America

Organisms naturalized outside their native range can reveal new life history patterns in new environments. Here, we compare life history patterns of American shad, Alosa sapidissima, from five rivers along the U.S. Pacific coast (introduced range) with contemporary data from the Atlantic coast source populations. The Pacific coast fish grew slower, matured at a younger age, and were less often iteroparous than conspecifics from the Hudson River and Susquehanna River sources. Differences among the Pacific coast populations indicated that some combination of phenotypic plasticity and genetic adaptation has occurred since the transplants in the 1870s. Microchemical analysis of otoliths from returning adults demonstrated an immature, extended freshwater life history form, locally known as “mini-shad”. These fish remain in the river for at least 1 year or enter salt water briefly and then return to fresh water for several months prior to subsequent seaward migration and return as adults. This and other forms of variation (extent of estuary use and size at sea water entry) expand the understanding of Alosine migration and life history diversity.

Canadian Journal of Fisheries and Aquatic Sciences↗

The role of stand history in assessing forest impacts

Air pollution, harvesting practices, and natural disturbances can affect the growth of trees and forest development. To make predictions about anthropogenic impacts on forests, we need to understand how these factors affect tree growth. In this study the effect of disturbance history on tree growth and stand structure was examined by using a computer model of forest development. The model was run under the climatic conditions of east Tennessee, USA, and the results compared to stand structure and tree growth data from a yellow poplar-white oak forest. Basal area growth and forest biomass were more accurately projected when rough approximations of the thinning and fire history typical of the measured plots were included in the simulation model. Stand history can influence tree growth rates and forest structure and should be included in any attempt to assess forest impacts.

Environmental Management↗

Digital data in support of studies and assessments of coal and petroleum resources in the Appalachian basin

The Appalachian basin is a mature basin containing abundant oil, gas, and coal resources. Its fossil-fuel-bearing strata range in age from Cambrian to Permian and extend over the States of New York, Pennsylvania, Maryland, Ohio, West Virginia, Virginia, Kentucky, Tennessee, Georgia, and Alabama. The basin has provided abundant fossil fuels to support the Nation’s economic growth for at least 150 years and U.S. Geological Survey (USGS) assessments suggest that substantial untapped resources remain. A merger of new and old geologic data and ideas is required to locate and extract those remaining resources. This chapter brings together abundant existing datasets in a common and integrated spatial format to advance our understanding of the distribution, geologic framework, burial history, and geochemical character of the basin’s oil, gas, and coal resources. These datasets support the information and findings in chapters B through G of this volume, which include (1) geologic cross sections, seismic profiles, and burial history models that document the depositional and structural framework of the basin; (2) assessments of Carboniferous coal-bed gas and Devonian shale gas; (3) studies about the distribution of oil, gas, and coal fields and the geochemistry of natural gas and oil; and (4) a history of fossil-fuel production in the basin. The data that supported these studies were refined and made more accessible using geographic information system (GIS) tools. The following types of data are included: (1) the bedrock geology of States included within the boundary of the Appalachian basin, (2) the locations of oil and gas wells and fields, (3) data produced for the National Oil and Gas Assessment, and (4) the stratigraphy, geochemistry, and production of coal. Data layers are available in shapefile and Zipped Keyhole Markup Language (KMZ) formats, which can be viewed using ArcGIS, Google Earth, or any software package that supports these data formats. Metadata for these datasets are available in HTML and XML formats. Metadata files contain information about the sources of data used to create the dataset, the creation process steps, the data quality, the geographic coordinate system and horizontal datum used for the dataset, the values of attributes used in the dataset table, information about the publication and the publishing organization, and other information that may be useful to the reader. All links in the metadata were valid at the time of compilation. Some of these links may no longer be valid. No attempt has been made to determine the new online location (if one exists) for the data.

Appalachian basin↗

Population and harvest dynamics of midcontinent sandhill cranes

Sandhill cranes ( Antigone canadensis ) inhabiting the midcontinent of North America have been hunted since the 1960s under management goals of maintaining abundance, retaining geographic distribution, and maximizing sustainable harvest. Some biologists have raised concerns regarding harvest sustainability because sandhill cranes have lower reproductive rates than other game birds. We summarized demographic information in an age-structured matrix model to better understand population dynamics and harvest. Population indices and recovered harvest since the early 1980s suggest midcontinent sandhill cranes have experienced an average long-term annual growth of 0.9%; meanwhile, harvest has increased 1.8% annually. We found that adult survival and recruitment rates estimated from field data required modest adjustments (1-3%) so that model-derived growth rates matched growth estimated from a long-term survey (0.887 adult survival and 0.199 females per breeding female). Considering 0.9% long-term annual growth, sandhill cranes could be harvested at a rate of 6.6% if harvest was additive to natural mortality (assumed to be 0.05) or 11.3% if harvest and natural mortality was compensatory. Life-history characteristics for long-lived organisms and demographic evidence suggested that hunter harvest was primarily additive. Differential harvest rates of segments of midcontinent sandhill cranes derived from differential exposure to hunting suggested potentially unsustainable harvest for greater sandhill cranes ( A. c. tabida ) from 2 breeding segments. Overall, demographic evidence suggests that the harvest of midcontinent sandhill cranes has been managed sustainably. Monitoring activities that reduce nuisance variation and estimate vital and harvest rates by subspecies would support continued management of sandhill cranes that are of great interest to hunters and bird watchers.

Nebraska↗

Trophic strategies, animal diversity and body size

A primary difference between predators and parasites is the number of victims that an individual attacks throughout a life-history stage. A key division within natural enemies is whether a successful attack eliminates the fitness of the prey or the host. A third distinctive axis for parasites is whether the host must die to further parasite development. The presence or absence of intensity-dependent pathology is a fourth factor that separates macroparasites from microparasites; this also distinguishes between social and solitary predators. Combining these four dichotomies defines seven types of parasitism, seven corresponding parasites, three forms of predation and, when one considers obligate and facultative combinations of these forms, four types of predator. Here, we argue that the energetics underlying the relative and absolute sizes of natural enemies and their victims is the primary selective factor responsible for the evolution of these different trophic strategies.

Trends in Ecology and Evolution↗

The skin I live in: Pathogenesis of white-nose syndrome of bats

The emergence of white-nose syndrome (WNS) in North America has resulted in mass mortalities of hibernating bats and total extirpation of local populations. The need to mitigate this disease has stirred a significant body of research to understand its pathogenesis. Pseudogymnoascus destructans , the causative agent of WNS, is a psychrophilic (cold-loving) fungus that resides within the class Leotiomycetes, which contains mainly plant pathogens and is unrelated to other consequential pathogens of animals. In this review, we revisit the unique biology of hibernating bats and P . destructans and provide an updated analysis of the stages and mechanisms of WNS progression. The extreme life history of hibernating bats, the psychrophilic nature of P . destructans , and its evolutionary distance from other well-characterized animal-infecting fungi translate into unique host–pathogen interactions, many of them yet to be discovered.

PLoS Pathogens↗

The interplay of species concepts, taxonomy, and conservation: lessons from the Hawaiian avifauna

The Hawaiian Islands, with their unique geological history and geographic position, provide an excellent natural laboratory in which to evaluate currently competing biological (BSC) and phylogenetic (PSC) concepts of the species. Although the BSC as historically applied in archipelagic situations is shown to be flawed in producing overlumped polytypic species, it nevertheless remains the preferable concept for most practical purposes. A review of the taxonomic history and species limits in Hawaiian birds under both concepts reveals that, when properly applied, the BSC yields a species total remarkably close to that produced under the PSC, contrary to what many proponents of the latter have supposed. We propose that the widespread adoption of the PSC for conservation purposes is potentially harmful. The PSC trivializes the species taxon and introduces new problems of deciding when a population becomes diagnosable, the possibility that species could appear and disappear in a reticulate fashion, and the likelihood that genetically diagnosable but phenotypically identical, and therefore not field identifiable, populations could be ranked as species. All of these problems negatively impact such things as constructing credible and politically defensible lists of endangered species, the prioritization of limited conservation resources, and the gathering of field data. We contend the BSC is arguably a more rational concept that better supports the activities of both scientific and nonprofessional observers. Biological species limits in oceanic archipelagoes worldwide need to be reevaluated using modern concepts and technologies before rational conservation decisions can be made.

Hawaii↗

Land management strategies influence soil organic carbon stocks of prairie potholes of North America

Soil organic carbon (SOC) stocks of Prairie Pothole Region (PPR) wetlands in the central plains of Canada and the United States are highly variable due to natural variation in biota, soils, climate, hydrology, and topography. Land-use history (cropland, grassland) and land-management practices (drainage, restoration) also affect SOC stocks. We conducted a region-wide assessment of wetland SOC stocks using data from the Canadian and US portions of the PPR under various management types. Natural wetlands with no disturbance history in the wetland basin or surrounding catchment had considerably greater average SOC stocks in the upper (0–15 cm) soil profile than wetlands surrounded by cropland. Hydrologically restored wetlands did not show significantly greater SOC stocks than drained wetlands, but wetlands surrounded by restored grasslands did have greater SOC stocks in the upper soil profile than those surrounded by croplands. Similarities among cropped and restored wetlands likely were due to insufficient time since restoration, as well as high variability attributable to several environmental factors within the region. We conclude that avoided loss of natural wetlands from drainage and avoided loss of native grasslands from cropping have the most benefit for preserving wetland SOC stocks. Robust PPR SOC models that incorporate multiple abiotic, biotic, and land-use factors are required to determine where and when restoration is most effective for SOC sequestration.

Book chapter↗

A 107-year-old coral from Florida Bay: barometer of natural and man- induced catastrophes?

The 107-yr growth history of a massive coral Solenastrea bournoni from Florida Bay was reconstructed with X-ray imagery from a single 4 in. diameter (10 cm) core that penetrated the exact epicenter of the 95.3 cm high colony. Growth increments totalled 952.9 mm, averaging 8.9 mm/yr over the life of the coral. Growth rate trends in the Florida Bay coral were compared to those in a Montastraea annularis of similar age from a nearby patch reef on the Atlantic Ocean side of the Florida Keys. It was concluded that growth rate, at least in these specimens, is a questionable indicator of past hurricanes and freezes. There does appear to be, however, a possible cause-and-effect relationship between major man-induced environmental perturbations and a prolonged reduction in growth rate in each coral's growth record. -from Authors

Bulletin of Marine Science↗

Coastal plain pond water quality and mercury contend of biota of the Long Island Central Pine Barrens and Mashomack Preserve: Effects of atmospheric deposition and human development

Pine barrens are considered an imperiled ecosystem in the northeastern U.S. The Suffolk County Pine Barrens, once the second largest in the Northeast, were substantially reduced and fragmented by development during the 20th century. The coastal plain ponds being considered in this study occur in central Suffolk County within the Long Island Central Pine Barrens region. This highly unique natural environment, embedded with forests and woodlands, resulted from its glacial origins and a land use history that predates European colonization. Included in this study was The Nature Conservancy’s Mashomack Preserve, located on Shelter Island between Peconic Bay and Gardiner’s Bay. There are no freshwater ponds in the Mashomack Preserve, but this area was included with the Central Pine Barrens investigation, because Shelter Island has a similar geologic and land-use history that has resulted in a similarly unique low-nutrient forest and woodland ecosystem with extremely coarse-textured soils.

New York↗

Spatial reconstructions and comparisons of historic snow avalanche frequency and extent using tree rings in Glacier National Park, Montana, U.S.A.

Natural snow avalanches have periodically damaged infrastructure and disrupted railroad and highway traffic at the southwestern corner of Glacier National Park, Montana. The 94-year history of these disruptions constitutes an uncommon record of natural avalanches spanning over nine decades and presents a unique opportunity to examine how natural avalanche frequency and minimum extent have varied over time due to climatic or biophysical changes. This study compared the historic record of natural avalanches in one avalanche path with tree-ring evidence of avalanches from 109 cross sections and increment cores collected in the same path. Results from combined historic and tree-ring records yielded 27 avalanche years in the 1910-2003 chronology, with the historic record alone underestimating avalanche years by half. Mean return period was 3.2 years. Interpolated maps allowed for more spatially precise estimates of return periods throughout the runout zone than previous studies. The maps show return periods increase rapidly downslope from 2.3 to 25 years. Avalanche years were associated with positive Snow Water Equivalent anomalies at a nearby snow course. Minimum avalanche extent was highly variable but not associated with snowpack anomalies. Most avalanche years coincided with years in which the mean January-February Pacific Decadal Oscillation (PDO) and El Nin??o-Southern Oscillation (ENSO) 3.4 indices were neutral. The findings suggest that changes in Pacific climate patterns that influence snowfall could also alter the frequency of natural snow avalanches and could thus change disturbance patterns in the montane forests of the canyon. ?? 2008 Regents of the University of Colorado.

Arctic, Antarctic, and Alpine Research↗

Geochemistry of Florida Bay sediments: Nutrient history at five sites in eastern and central Florida Bay

Recent seagrass dieoff and massive microalgal blooms have focused attention on the health of the Florida Bay ecosystem. Changes in nutrient input and the nutrient dynamics of Florida Bay are hypothesized to be linked to these problems, but crucial baseline information is still lacking. Efforts to restore Florida Bay to its natural condition will require information on the nutrient history of the bay. The purpose of this study was to examine distributions of organic C, total N, and total P in carbonate sediments from sites of continuous and known sedimentation rate (210Pb and 137Cs dated), in eastern and central Florida Bay. These sediments provide a record of historical changes in the C, N, and P load to the eastern and central bay. Analyses were conducted on sediments from cores collected at five sites, and on buried seagrass fragments at two sites. At three of the sites, sediments from seagrass-covered and adjacent barren areas were examined to determine differences in sedimentary geochemistry. Stable isotope analyses (??13C and ??15N) of sedimentary organic C and total N and of buried seagrass fragments were also carried out at two sites to examine possible changes in nutrient sources to the estuary. Results were consistent with recent increases in N and P in eastern Florida Bay, beginning in the early to mid 1980's. The timing of the increase in nutrient load observed in the sediment data directly preceded the first observations of massive microalgal blooms and seagrass dieoff in Florida Bay in 1987. The observed nutrification was greater for P than N, and was most pronounced at the most northeasterly site sampled (Pass Key). Isotope data (??15N) suggested that an increase in algal production accompanied the increase in N load at the Pass Key site. Along record of organic C, total N, and total P distributions from Whipray Basin in central Florida Bay showed historical peaks (mid 1700's and late 1800's) in organic C and total N, but not total P; these enrichments were nearly equivalent to recent inputs to the estuary. Barren areas were observed to have generally lower concentrations of organic C, total N, and total P in near surface sediments compared to seagrass-covered areas, but had generally similar concentrations in deeper sediments. This suggested that barren areas adjacent to seagrass-covered sites were places where relict sediment was physically transported and covered seagrass beds. This dataset provides an historical view of changes in nutrient inputs to Florida Bay, and baseline information needed for nutrient modeling of the bay.

Journal of Coastal Research↗

Late Pleistocene and Holocene uplift history of Cyprus: implications for active tectonics along the southern margin of the Anatolian microplate

The nature of the southern margin of the Anatolian microplate during the Neogene is complex, controversial and fundamental in understanding active plate-margin tectonics and natural hazards in the Eastern Mediterranean region. Our investigation provides new insights into the Late Pleistocene uplift history of Cyprus and the Troodos Ophiolite. We provide isotopic ( 14 C) and radiogenic (luminescence) dates of outcropping marine sediments in eastern Cyprus that identify periods of deposition during marine isotope stages (MIS) 3, 4, 5 and 6. Past sea-levels indicated by these deposits are c. 95±25 m higher in elevation than estimates of worldwide eustatic sea-level. An uplift rate of c. 1.8 mm/year and possibly as much as c. 4.1 mm/year in the past c. 26–40 ka is indicated. Holocene marine deposits also occur at elevations higher than those expected for past SL and suggest uplift rates of c. 1.2–2.1 mm/year. MIS-3 marine deposits that crop out in southern and western Cyprus indicate uniform island-wide uplift. We propose a model of tectonic wedging at a plate-bounding restraining bend as a mechanism for Late Pleistocene to Holocene uplift of Cyprus; uplift is accommodated by deformation and seismicity along the margins of the Troodos Ophiolite and re-activation of its low-angle, basal shear zone.

Geological Society, London, Special Publications: ↗