Alaska's rare earth deposits and resource potential
James C. Barker, Bradley S. Van Gosen
2012, Mining Engineering (64) 20-32
Alaska’s known mineral endowment includes some of the largest and highest grade deposits of various metals, including gold, copper and zinc. Recently, Alaska has also been active in the worldwide search for sources of rare earth elements (REE) to replace exports now being limitedby China. Driven by limited supply of...
Carbon dioxide stripping in aquaculture. part 1: terminology and reporting
John Colt, Barnaby Watten, Tim Pfeiffer
2012, Aquacultural Engineering (47) 27-37
The removal of carbon dioxide gas in aquacultural systems is much more complex than for oxygen or nitrogen gas because of liquid reactions of carbon dioxide and their kinetics. Almost all published carbon dioxide removal information for aquaculture is based on the apparent removal value after the CO2(aq) + HOH...
Source characterization of near-surface chemical explosions at SAFOD
Fred F. Pollitz, Justin Rubinstein, William Ellsworth
2012, Bulletin of the Seismological Society of America (102) 1348-1360
A series of near‐surface chemical explosions conducted at the San Andreas Fault Observatory at Depth (SAFOD) main hole were recorded by high‐frequency downhole receiver arrays in April 2005. These seismic recordings at depths ranging from the surface to 2.3 km constrain the shallow velocity and attenuation structure as well as...
Fixed recurrence and slip models better predict earthquake behavior than the time- and slip-predictable models 1: repeating earthquakes
Justin L. Rubinstein, William L. Ellsworth, Kate Huihsuan Chen, Naoki Uchida
2012, Journal of Geophysical Research B: Solid Earth (117)
The behavior of individual events in repeating earthquake sequences in California, Taiwan and Japan is better predicted by a model with fixed inter-event time or fixed slip than it is by the time- and slip-predictable models for earthquake occurrence. Given that repeating earthquakes are highly regular in both inter-event time...
Bulk rock composition and geochemistry of olivine-hosted melt inclusions in the Grey Porri Tuff and selected lavas of the Monte dei Porri volcano, Salina, Aeolian Islands, southern Italy
Angela L. Doherty, Robert J. Bodnar, Benedetto De Vivo, Wendy A. Bohrson, Harvey E. Belkin, Antonia Messina, Robert J. Tracy
2012, Central European Journal of Geosciences (4) 338-355
The Aeolian Islands are an arcuate chain of submarine seamounts and volcanic islands, lying just north of Sicily in southern Italy. The second largest of the islands, Salina, exhibits a wide range of compositional variation in its erupted products, from basaltic lavas to rhyolitic pumice. The Monte dei Porri eruptions...
Rare earths, the lanthanides, yttrium and scandium
G. Bedinger, D. Bleiwas
2012, Mining Engineering (64) 86-88
In 2011, rare earths were recovered from bastnasite concentrates at the Mountain Pass Mine in California. Consumption of refined rare-earth products decreased in 2011 from 2010. U.S. rare-earth imports originated primarily from China, with lesser amounts from Austria, Estonia, France and Japan. The United States imported all of its demand...
Fragilariopsis diatom evolution in Pliocene and Pleistocene Antarctic shelf sediments
Charlotte Sjunneskog, Christina Riesselman, Diane Winter, Reed Scherer
2012, Micropaleontology (58) 273-289
The late Pliocene – early Pleistocene sediment record in the AND-1B core from the McMurdo Sound, Ross Sea, Antarctica, displays a rich diversity and high abundance of diatoms, including several new morphologies within the genus Fragilariopsis. These new morphologies exhibit similarities to the extinct late Miocene/early Pliocene species Fragilariopsis aurica...
Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge
M.O. Cuthbert, R. Mackay, J. R. Nimmo
2012, Hydrology and Earth System Sciences (9) 8455-8492
Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is developed and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the...
Modeling species invasions in Ecopath with Ecosim: an evaluation using Laurentian Great Lakes models
Brian J. Langseth, Mark Rogers, Hongyan Zhang
2012, Ecological Modelling (247) 251-261
Invasive species affect the structure and processes of ecosystems they invade. Invasive species have been particularly relevant to the Laurentian Great Lakes, where they have played a part in both historical and recent changes to Great Lakes food webs and the fisheries supported therein. There is increased interest in understanding...
High-frequency remote monitoring of large lakes with MODIS 500 m imagery
Ian M. McCullough, Cynthia S. Loftin, Steven A. Sader
2012, Remote Sensing of Environment (124) 234-241
Satellite-based remote monitoring programs of regional lake water quality largely have relied on Landsat Thematic Mapper (TM) owing to its long image archive, moderate spatial resolution (30 m), and wide sensitivity in the visible portion of the electromagnetic spectrum, despite some notable limitations such as temporal resolution (i.e., 16 days), data pre-processing...
Multiple functions of a multi-component mating pheromone in sea lamprey Petromyzon marinus
N.S. Johnson, S.-S. Yun, T.J. Buchinger, W. Li
2012, Journal of Fish Biology (80) 538-554
The role of the C24 sulphate in the mating pheromone component, 7α,12α,24-trihydroxy-5α-cholan-3-one 24-sulphate (3kPZS), to specifically induce upstream movement in ovulated female sea lampreys Petromyzon marinus was investigated. 7α,12α-dihydroxy-5α-cholan-3-one 24-oic acid (3kACA), a structurally similar bile acid released by spermiated males, but lacking the C24 sulphate ester, was tested in...
Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA
Leora Nanus, David W. Clow, Jasmine E. Saros, Verlin C. Stephens, Donald H. Campbell
2012, Environmental Pollution (166) 125-135
Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (−1 yr−1) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance...
Biogeochemistry: unexpected uptake
Jayne Belnap
2012, Nature Geoscience (5) 443-444
Lichens, cyanobacteria, mosses and algae coat many terrestrial surfaces. These biological covers turn out to play an important role in the global cycling of carbon and nitrogen....
Does translocation influence physiological stress in the desert tortoise?
K.K. Drake, K.E. Nussear, T. C. Esque, A.M. Barber, K.M. Vittum, P.A. Medica, C.R. Tracy, K.W. Hunter
2012, Animal Conservation (15) 560-570
Wildlife translocation is increasingly used to mitigate disturbances to animals or habitat due to human activities, yet little is known about the extent to which translocating animals causes stress. To understand the relationship between physiological stress and translocation, we conducted a multiyear study (2007–2009) using a population of desert tortoises...
Mineral resource of the month: dimension stone
Thomas P. Dolley
2012, Earth (57) 65-65
The article offers information on dimension stone (DS) that are quarried as natural rock for a specific size and dimension chosen for its color, strength, durability. Varieties of metamorphic, igneous or sedimentary rocks are used but DS rocks are mainly marble, granite and slate that can be found from Maine...
Increased temperature and altered summer precipitation have differential effects on biological soil crusts in a dryland ecosystem
Shannon L. Johnson, Cheryl R. Kuske, Travis D. Carney, David C. Housman, La Verne Gallegos-Graves, Jayne Belnap
2012, Global Change Biology (18) 2583-2593
Biological soil crusts (biocrusts) are common and ecologically important members of dryland ecosystems worldwide, where they stabilize soil surfaces and contribute newly fixed C and N to soils. To test the impacts of predicted climate change scenarios on biocrusts in a dryland ecosystem, the effects of a 2–3 °C increase...
Development of a real-time PCR assay for detection of planktonic red king crab (Paralithodes camtschaticus (Tilesius 1815)) larvae
Pamela C. Jensen, Maureen K. Purcell, J. Frank Morado, Ginny L. Eckert
2012, Journal of Shellfish Research (31) 917-924
The Alaskan red king crab (Paralithodes camtschaticus) fishery was once one of the most economically important single-species fisheries in the world, but is currently depressed. This fishery would benefit from improved stock assessment capabilities. Larval crab distribution is patchy temporally and spatially, requiring extensive sampling efforts to locate and track...
Estimating risks to aquatic life using quantile regression
Travis S. Schmidt, William H. Clements, Brian S. Cade
2012, Freshwater Science (31) 709-723
One of the primary goals of biological assessment is to assess whether contaminants or other stressors limit the ecological potential of running waters. It is important to interpret responses to contaminants relative to other environmental factors, but necessity or convenience limit quantification of all factors that influence ecological potential. In...
Short-term impacts of a 4-lane highway on black bears in eastern North Carolina
Frank T. van Manen, Matthew F. McCollister, Jeremy M. Nicholson, Laura M. Thompson, Jason L. Kindall, Mark D. Jones
2012, Wildlife Monographs (181) 1-35
Among numerous anthropogenic impacts on terrestrial landscapes, expanding transportation networks represent one of the primary challenges to wildlife conservation worldwide. Larger mammals may be particularly vulnerable because of typically low densities, low reproductive rates, and extensive movements. Although numerous studies have been conducted to document impacts of road networks on...
Developing spatially explicit footprints of plausible land-use scenarios in the Santa Cruz Watershed, Arizona and Sonora
Laura M. Norman, Mark Feller, Miguel L. Villarreal
2012, Landscape and Urban Planning (107) 225-235
The SLEUTH urban growth model is applied to a binational dryland watershed to envision and evaluate plausible future scenarios of land use change into the year 2050. Our objective was to create a suite of geospatial footprints portraying potential land use change that can be used to aid binational decision-makers...
Mineral resource of the month: mercury
Water Resources Division, U.S. Geological Survey
2012, Earth (57) 61-61
The article offers information on mercury, a mineral commodity used in industrial and small-scale gold mining applications. Mercury has been reported to be used for amalgamation with gold since the Roman times. Mercury from cinnabar from Almadén, Spain has been used by Romans and has been continued to be used...
Estimation of wildfire size and risk changes due to fuels treatments
M.A. Cochrane, C.J. Moran, M.C. Wimberly, A.D. Baer, M.A. Finney, K.L. Beckendorf, J. Eidenshink, Z. Zhu
2012, International Journal of Wildland Fire (21) 357-367
Human land use practices, altered climates, and shifting forest and fire management policies have increased the frequency of large wildfires several-fold. Mitigation of potential fire behaviour and fire severity have increasingly been attempted through pre-fire alteration of wildland fuels using mechanical treatments and prescribed fires. Despite annual treatment of more...
Discovering shared segments on the migration route of the bar-headed goose by time-based plane-sweeping trajectory clustering
Ze Luo, Yan Baoping, John Y. Takekawa, Diann J. Prosser
2012, Journal of Information and Computational Science (9) 5093-5100
We propose a new method to help ornithologists and ecologists discover shared segments on the migratory pathway of the bar-headed geese by time-based plane-sweeping trajectory clustering. We present a density-based time parameterized line segment clustering algorithm, which extends traditional comparable clustering algorithms from temporal and spatial dimensions. We present a...
Ecology of bison, elk, and vegetation in an arid ecosystem
Kathryn A. Schoenecker
2012, Thesis
Herbivory has profound effects on vegetation production and structure in many different plant communities. The influence of herbivory on plants and ultimately ecosystem processes is shaped by the types of plants consumed, the intensity of herbivory, the evolutionary history of grazing, and the availability of water and nutrients to plants....
A meeting of the waters: interdisciplinary challenges and opportunities in tidal rivers
Scott H. Ensign, Gregory B. Noe, Cliff R. Hupp, Sergio Fagherazzi
2012, Eos, Transactions, American Geophysical Union (95) 455-456
At the interface of estuarine tides and freshwater rivers lie wetland and aquatic ecosystems, which experience dramatic effects of sea level rise. There, nontidal channels and riparian floodplains are transforming into tidal ecosystems, and tidal freshwater ecosystems are receiving increasing salinity. These river-floodplain systems have both fluvial characteristics, including meandering...
