scholarly journals Lead Isotopes in North American Precipitation record the presence of Saharan Dust

2021 ◽  
pp. 1-24
Author(s):  
Sean R. Scott ◽  
Jason P. Dunion ◽  
Mark L. Olson ◽  
David A. Gay
Keyword(s):  
United States ◽  
North America ◽  
Inductively Coupled Plasma ◽  
Lead Isotopes ◽  
Southeastern United States ◽  
Isotopic Shift ◽  
Saharan Dust ◽  
Southeastern Us ◽  
Amazon Rain Forest ◽  
Precipitation Record

AbstractAtmospheric dust is an important mass transfer and nutrient supply process in Earth surface ecosystems. For decades, Saharan Dust has been hypothesized as a supplier of nutrients to the Amazon Rain Forest and Eastern North America. However, isotope studies aimed at detecting Saharan dust in the American sedimentary record have been ambiguous. A large Saharan dust storm emerged off the coast of Africa in June 2020 and extended into southeastern United States. This storm provided a means to evaluate the influence of Saharan dust in North America confirmed by independent satellite and ground observations. Precipitation samples from 17 sites within the National Atmospheric Deposition Program (NADP) were obtained from throughout the southeastern United States prior to, during, and after the arrival of Saharan dust. Precipitation samples were measured for their lead (Pb) isotopic composition, total Pb content, and 210Pb activity using multi-collector inductively coupled plasma mass spectrometry. We measured a significant isotopic shift (approximately 0.7 % in the 208Pb/206Pb relative to the 207Pb/206Pb) in precipitation that peaked in late June 2020 when the dust blanketed the southeastern US. However, the magnitude and short time period of the isotopic shift would make it difficult to detect in sedimentary records.

scholarly journals Progression of Sugarberry (Celtis laevigata) Dieback and Mortality in the Southeastern United States

2021 ◽  
Author(s):  
Emilee M Poole ◽  
Michael D Ulyshen ◽  
Scott Horn ◽  
Patrick Anderson ◽  
Chip Bates ◽  
...  
Keyword(s):  
United States ◽  
North America ◽  
Invasive Plants ◽  
Southeastern United States ◽  
Public Spaces ◽  
Canopy Gaps ◽  
Leaf Fall ◽  
Affected Area ◽  
Celtis Laevigata ◽  
Branch Dieback

Abstract The southeastern United States has been experiencing unexplained sugarberry (Celtis laevigata) mortality for over a decade, representing one of the most severe and widespread Celtis mortality episodes ever reported from North America. Here we describe external symptoms, progression of mortality, and the known geographic extent of the problem. More than half of all trees monitored at one site within the affected area died over five years of observation. Although many trees died within a year of first exhibiting symptoms (e.g., small yellow leaves, branch dieback, premature leaf fall), many others continued living for years after becoming symptomatic. A preliminary insecticide trial found no improvements in survivorship among trees treated with insecticides, emamectin benzoate and imidacloprid, relative to control trees. Our findings suggest the problem will likely continue and become more widespread in the coming years. Study Implications Sugarberry mortality in urban and forested environments is an ongoing problem that has the potential to spread throughout the southeastern United States and perhaps more widely, depending on the susceptibility of other native Celtis species. Many trees die within a year of first showing external symptoms, whereas others can live for many years after appearing symptomatic. Declining trees in rights-of-way and public spaces are presenting costly hazards to cities, and canopy gaps in natural areas are likely to facilitate the establishment and spread of invasive plants. Studies aimed at determining the cause of this problem are urgently needed.

Do centers of origin have a center?

Paleobiology ◽  
1981 ◽  
Vol 7 (3) ◽  
pp. 305-307 ◽  
Author(s):  
John C. Briggs
Keyword(s):  
United States ◽  
North America ◽  
Southeastern United States ◽  
Important Criterion ◽  
Centers Of Origin ◽  
Single Region ◽  
Evolutionary Radiation ◽  
A Current ◽  
Considerable Intensity

A current question being debated with considerable intensity is whether or not certain geographic areas act as centers of evolutionary radiation and supply species to other areas that are less active or less effective in an evolutionary sense. Darwin (1859) was the first to write about centers of origin which he called “single centers of creation.” He argued that each species was first produced within a single region and that it subsequently migrated from that area as far as its powers of migration and subsistence under past and present conditions permitted. Adams (1902), in discussing the influence of the southeastern United States as a center of distribution for the flora and fauna of North America, provided a series of criteria for the determination of “centers of dispersal.” His first, and evidently most important criterion was the location of “the greatest differentiation of a type.”

scholarly journals The Interannual Variability of the Haines Index over North America

2013 ◽  
Vol 52 (11) ◽  
pp. 2396-2409 ◽  
Author(s):  
Lejiang Yu ◽  
Shiyuan Zhong ◽  
Xindi Bian ◽  
Warren E. Heilman ◽  
Joseph J. Charney
Keyword(s):  
United States ◽  
Pacific Ocean ◽  
North America ◽  
Interannual Variability ◽  
Large Scale ◽  
Southern Oscillation ◽  
Southeastern United States ◽  
Lower Atmosphere ◽  
The Arctic ◽  
Fire Weather Index

AbstractThe Haines index (HI) is a fire-weather index that is widely used as an indicator of the potential for dry, low-static-stability air in the lower atmosphere to contribute to erratic fire behavior or large fire growth. This study examines the interannual variability of HI over North America and its relationship to indicators of large-scale circulation anomalies. The results show that the first three HI empirical orthogonal function modes are related respectively to El Niño–Southern Oscillation (ENSO), the Arctic Oscillation (AO), and the interdecadal sea surface temperature variation over the tropical Pacific Ocean. During the negative ENSO phase, an anomalous ridge (trough) is evident over the western (eastern) United States, with warm/dry weather and more days with high HI values in the western and southeastern United States. During the negative phase of the AO, an anomalous trough is found over the western United States, with wet/cool weather and fewer days with high HI, while an anomalous ridge occurs over the southern United States–northern Mexico, with an increase in the number of days with high HI. After the early 1990s, the subtropical high over the eastern Pacific Ocean and the Bermuda high were strengthened by a wave train that was excited over the tropical western Pacific Ocean and resulted in warm/dry conditions over the southwestern United States and western Mexico and wet weather in the southeastern United States. The above conditions are reversed during the positive phase of ENSO and AO and before the early 1990s.

scholarly journals Public entrepreneurs and the adoption of broad-based merit aid beyond the Southeastern United States

2013 ◽  
Vol 21 ◽  
pp. 58
Author(s):  
William Kyle Ingle ◽  
Ruth Ann Petroff
Keyword(s):  
United States ◽  
Diffusion Theory ◽  
Full Range ◽  
Southeastern United States ◽  
Merit Aid ◽  
Theoretical Frameworks ◽  
Southeastern Us ◽  
Public Colleges And Universities ◽  
Aid Programs ◽  
K 12

The concentration of broad-based merit aid adoption in the southeastern United States has been well noted in the literature. However, there are states that have adopted broad-based merit aid programs outside of the Southeast.  Guided by multiple theoretical frameworks, including innovation diffusion theory (e.g., Gray, 1973, 1994; Rogers, 2003), Roberts and King’s (1991) typology of public entrepreneurs, and Anderson’s (2003) stages of the policymaking process, this qualitative study sought to answer the following questions. First, in the absence of regional diffusion pressures, what internal determinants are reported as accounting for the diffusion of broad-based merit aid programs outside of the Southeastern US?  What types of public entrepreneurs were identified as playing key roles in establishing merit aid in states outside the southeastern US?  During which stages of the policymaking process were they active? We found that merit aid was a means of addressing an array of public problems, including low college going rates at in-state public colleges and universities, and weak K-12 accountability. Consistent factors reported as facilitating merit aid creation included a strong, vocal public advocate (governors and a university system president) and a desire to strengthen state economies and diversify workforces.  A full range of public entrepreneurs played key roles in developing merit aid in the sampled states. Political and executive entrepreneurs were in the forefront of merit aid efforts, but our data suggest that a cast of supporting public entrepreneurs were integral to the eventual adoption of broad-based merit aid in the sampled states.

scholarly journals The Sarracenia Pitcher Plants and Bog Gardening

2008 ◽  
pp. 79-99
Author(s):  
T Lawrence Mellichamp
Keyword(s):  
United States ◽  
North America ◽  
Extra Dimension ◽  
Southeastern United States ◽  
Short Note ◽  
Botanical Garden ◽  
Carnivorous Plants ◽  
Pitcher Plants ◽  
The Public ◽  
The World

The Sarracenia pitcher plants are among the world’s most beautiful and intriguing plants, and being carnivorous adds an extra dimension of fascination. They are endemic to North America – 10 species are found only in the southeastern United States and one species is widely distributed, from the northeastern US and across Canada. They are easy to cultivate if you understand their basic needs and are grown the world over. Every botanical garden should have them because they are so popular with the public. They go hand-in-hand with other unusual carnivorous plants to make a display that is captivating (puns intended!) to both children and adults. This paper covers types of pitcher plants, their habitats, brief descriptions of the species, a key to identification, cultivation and a short note on conservation.

REVIEW OF THE MYRMECOPHILOUS PTOMAPHAGUS, SUBGENUS ECHINOCOLEUS (NEW STATUS), OF NORTH AMERICA (COLEOPTERA: LEIODIDAE: CHOLEVINAE: PTOMAPHAGINI)

1997 ◽  
Vol 129 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Stewart B. Peck ◽  
Pedro Gnaspini
Keyword(s):  
United States ◽  
Phylogenetic Analysis ◽  
North America ◽  
Body Length ◽  
Southeastern United States ◽  
Western United States ◽  
Harvester Ants

AbstractWe here give Echinocoleus new ranking as a subgenus of Ptomaphagus. Ptomaphagus (Echinocoleus) acutus sp.nov. is described from the southeastern United States (Alabama, Georgia, Florida). It is the most plesiotypic member of a group in which all other species live in the western United States and (probably) adjacent Mexico. All are myrmecophilous with Pogonomyrmex and Aphaenogaster (= Novomessor) harvester ants. A phylogenetic analysis is given for the subgenus. The main synapomorphies of Echinocoleus, which are mostly interrelated with myrmecophily, are reduction of body length and broadening of elytra, reduction of antennal length, verticalization of mesocoxal insertion, reduction of mesosternal carina, body with a golden pubescense, and a pointed projection at the end of the spermatheca.

Distribution of an Invasive Weevil, Pseudocneorhinus bifasciatus Roelofs, in the Southeastern United States

2005 ◽  
Vol 40 (1) ◽  
pp. 25-30 ◽  
Author(s):  
A. G. Wheeler ◽  
David W. Boyd
Keyword(s):  
United States ◽  
North Carolina ◽  
South Carolina ◽  
North America ◽  
Southeastern United States ◽  
Ornamental Plants ◽  
Review Of The Literature ◽  
Northeastern United States

The twobanded Japanese weevil, Pseudocneorhinus bifasciatus Roelofs, first found in North America near Philadelphia, PA, in 1914, is better known in the northeastern United States than in the Southeast. Based on examination of specimens in 11 museums, fieldwork, and review of the literature, we document the presence of this pest of ornamental plants in Alabama (3 counties), Georgia (12), North Carolina (16), and South Carolina (19). The southeastern distribution is mapped, and locality and date are provided for the first collection in each state: North Carolina, 1955; Georgia, 1956; South Carolina, 1966; and Alabama, 1970.

scholarly journals Seasonal Variation and Spatial Patterns of the Atmospheric Component of the Pacific Decadal Oscillation

2013 ◽  
Vol 26 (5) ◽  
pp. 1575-1594 ◽  
Author(s):  
Catrin M. Mills ◽  
John E. Walsh
Keyword(s):  
United States ◽  
North America ◽  
Air Temperature ◽  
Pacific Decadal Oscillation ◽  
Southern Oscillation ◽  
Grid Point ◽  
Southeastern United States ◽  
Surface Air Temperature ◽  
The Pacific ◽  
Difference Fields

Abstract The Pacific decadal oscillation (PDO) is an El Niño–Southern Oscillation (ENSO)-like climate oscillation that varies on multidecadal and higher-frequency scales, with a sea surface temperature (SST) dipole in the Pacific. This study addresses the seasonality, vertical structure, and across-variable relationships of the local North Pacific and downstream North American atmospheric signal of the PDO. The PDO-based composite difference fields of 500-mb geopotential height, surface air temperature, sea level pressure, and precipitation vary not only across seasons, but also from one calendar month to another within a season, although month-to-month continuity is apparent. The most significant signals occur in western North America and in the southeastern United States, where a positive PDO is associated with negative heights, consistent with underlying temperatures in the winter. In summer, a negative precipitation signal in the southeastern United States associated with a positive PDO phase is consistent with a ridge over the region. When an annual harmonic is fit to the 12 monthly surface air temperature differences at each grid point, the PDO temperature signal peaks in winter in most of North America, while a peak in summer occurs in the southeastern United States. Approximately 25% of the variance of the PDO index is accounted for by ENSO. Atmospheric composite differences based on a residual (ENSO linearly removed) PDO index have many similarities to those of the full PDO signal.

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