365 research outputs found

    Micro-to macro-scale foraminiferal distributions: the contributions of Martin A. Buzas

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    The research that Martin A. Buzas has published over the past more than 40 years has influenced us greatly. That research has many strands that cannot be dealt with in this short review. However, the theme of micro- to macroscale foraminiferal distributions is interwoven throughout Buzas's research career. Distributions are something that Buzas is very fond of. He was trained in statistics as well as foraminifera and so it was inevitable that he would combine his knowledge of statistical distributions with foraminiferal distributions at several different scales. He has studied the distribution of foraminifera at microscales, horizontally within a 10 cm² area of the sea floor or vertically, cm by cm within a 20 cm core. He has also worked at the mesoscale, quantifying, through the pioneering use of the General Linear Model, the relationship of foraminiferal distributions and environmental variables in space and time. This research led to the hypothesis of pulsating patches. He has worked at the macroscale with S. J. Culver, defining the distribution of benthic foraminiferal provinces, showing that all foraminiferal distributions, particularly around the coasts of North and Central America, belong to the same statistical distribution. Their work has documented the assembly and disassembly of communities and the latitudinal patterns of deep-sea benthic foraminiferal diversity in the Atlantic basin. Most recently, with his coauthor, mathematical statistician L. C. Hayek, Buzas has delved deep into the intricacies of species diversity and solved a 50 year-old supposedly intractable problem of mathematically relating species richness with species evenness. This work led to the introduction of new approaches to understanding community structure and recognizing boundaries between adjacent communities (SHE analysis). Many of us work long hours and publish many papers over our careers but few of us truly influence the fundamentals of our science. Marty Buzas is one micropaleontologist whose work will be of lasting significance

    Infaunal Marsh Foraminifera From the Outer Banks, North Carolina, USA

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    The distribution and abundance of live (rose Bengal stained) and dead, shallow infaunal (0–1 cm depth) and deep infaunal (\u3e1 cm depth) benthic foraminifera have been documented at three locations representing different salinity settings on the fringing marshes along the Pamlico Sound and Currituck Sound coasts of North Carolina’s Outer Banks. Two cores taken at each site represent the lower and higher marsh. Twenty-two taxa were recorded as live. Of these, eight taxa were found only at shallow infaunal depths; the other 14 taxa occur at deep infaunal depths in one or more cores. Only Jadammina macrescens and Tiphotrocha comprimata were recorded as living in all six cores. The distributions of the other taxa were restricted by combinations of infaunal depth, salinity regime and location on the marsh. The tests of infaunal foraminifera were generally more likely to be preserved in the lower marsh than the higher marsh at low- and intermediate-salinity sites. The opposite pattern was evident at the high-salinity site but this may be due to the low numbers of deep infaunal specimens recovered. Arenoparrella mexicana, Haplophragmoides wilberti, Jadammina macrescens and Trochammina inflata are the most resistant taxa, whereas Miliammina fusca is the species whose tests are most likely to be lost to post-mortem degradation. In five of the six cores, foraminiferal assemblages and populations do not differ significantly with depth which suggests that the foraminifera of the 0–1 cm depth interval provide an adequate model upon which paleoenvironmental (including former sea level) reconstructions can be based

    Modern saltmarsh diatom distributions of the Outer Banks, North Carolina, and the development of a transfer function for high resolution reconstructions of sea level

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    We collected modern diatom samples from Currituck Barrier Island, Oregon Inlet and Pea Island marshes, Outer Banks, North Carolina, USA, which have different salinity regimes due to their varying distances from a major barrier island inlet. Multivariate analyses separate the saltmarsh diatom assemblages into distinct elevational zones, dominated by differing abundances of polyhalobous, mesohalobous and oligohalobous taxa, suggesting that the distribution of saltmarsh diatoms is a direct function of elevation, with the most important controlling factors being the duration and frequency of subaerial exposure. We developed the first diatom-based transfer function for the east coast of North America to reconstruct former sea levels based upon the relationship between diatom assemblage and elevation. Results imply that this is possible to a precision of ±0.08 m, superior to most similar studies from temperate, mid-latitude environments. The transfer function is used to construct a relative sea-level curve from fossil assemblages from Salvo, North Carolina. These results suggest a sea-level rise of 0.7 m over the last c. 150 years, at an average of c. 3.7 mm year−1. This is consistent with existing sea-level data, and illustrates the utility of the transfer function approach

    Genetic and Phylogenetic Divergence of Feline Immunodeficiency Virus in the Puma (Puma concolor)

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    Feline immunodeficiency virus (FIV) is a lentivirus which causes an AIDS-like disease in domestic cats (Felis catus). A number of other felid species, including the puma (Puma concolor), carry a virus closely related to domestic cat FIV. Serological testing revealed the presence of antibodies to FIV in 22% of 434 samples from throughout the geographic range of the puma. FIV-Pco pol gene sequences isolated from pumas revealed extensive sequence diversity, greater than has been documented in the domestic cat. The puma sequences formed two highly divergent groups, analogous to the clades which have been defined for domestic cat and lion (Panthera leo) FIV. The puma clade A was made up of samples from Florida and California, whereas clade B consisted of samples from other parts of North America, Central America, and Brazil. The difference between these two groups was as great as that reported among three lion FIV clades. Within puma clades, sequence variation is large, comparable to between-clade differences seen for domestic cat clades, allowing recognition of 15 phylogenetic lineages (subclades) among puma FIV-Pco. Large sequence divergence among isolates, nearly complete species monophyly, and widespread geographic distribution suggest that FIV-Pco has evolved within the puma species for a long period. The sequence data provided evidence for vertical transmission of FIV-Pco from mothers to their kittens, for coinfection of individuals by two different viral strains, and for cross-species transmission of FIV from a domestic cat to a puma. These factors may all be important for understanding the epidemiology and natural history of FIV in the puma
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