Beggiatoa in microbial mats at hydrocarbon vents in the Gulf of Mexico and Warm Mineral Springs,Florida

Microbial mats were collected from a variety of sites near hydrocarbon vents along the slope in the northern Gulf of Mexico and, for comparison, from Warm Mineral Springs, Florida, USA. A predominant microorganism in each of the mats was the giant bacterium,Beggiatoa. Diameters of the bacterial filaments ranged from about 6 µm to approximately 200 µm. The latter organisms are the largest prokaryotic organisms yet found. All filaments over about 10 µm in diameter contained a large central vacuole, producing a cell with the cytoplasm as a cylindrical tube underlying the cytoplasmic membrane. Sulfur globules were confined to this peripheral layer. Push cores often contained pyrite tubules whose appearance is suggestive of aBeggiatoa origin. Determinations of ¹³C inBeggiatoa mats from vents along the Louisiana slope yielded values in the range of –26.6 to –27.9 (PDB), suggesting an unusually high degree of isotope fractionation (–24.9) relative to the carbon source in the ambient seawater, which is typical of sulfur-oxidizing chemoautotrophs. The presence of S^O (elemental sulfur) within cells ofBeggiatoa resulting from oxidation of H₂S supports the importance of bacterial sulfate reduction processes in the underlying vents for the sustenance of theBeggiatoa mats.     

Micropaleontological,mineralogical, and geochemical record in late quaternary cores from abyssal Grenada Basin

Clay mineralogy and trace-element geochemistry of two abyssal cores indicate that the primary source of surface-current-transported detrital material in the southern Grenada Basin changed from a continental, South American terrane to a volcanic, Lesser Antillean terrane at the end of the Pleistocene. The record of benthic foraminiferal assemblages demonstrates that the Caribbean Bottom Water (CBW) was relatively oxygen poor and less corrosive in late Pleistocene glacial times than in interglacial times. The change in the properties of CBW in the Holocene was related to a renewed influx of North Atlantic Deep Water in the Caribbean.     

Barite chimneys on the Gulf of Mexico slope: Initial report on their petrography and geochemistry

Barite chimneys associated with hydrocarbonrich fluid venting were recently documented and sampled on the Gulf of Mexico slope offshore Louisiana at 510–520 m water depth. The chimneys are dominated by barite associated with minor amounts of pyrite, iron oxide, Mg calcite, and detrital silicates. The barite displays distinct string-like and dendritic-like morphologies assembled from rosette-shaped crystals that are typically 20–40 µm in diameter. The chimneys exhibit macroscopic growth layers 1–5 mm thick, which alternate between dark gray and light yellow colors. The dark layers are dominated by string barites associated with disseminated pyrite, while the light layers are dominated by dendritic barites with little or no pyrite. The barites are anomalously enriched in Sr (average 15.5 mol% and maximum 30 mol%) and Ca (average 2.8 mol% and maximum 4.6 mol%), and exhibit rhythmic, paired, microscopic light and dark bands. The exact origin of the barites and their mode of deposition has not yet been elucidated, but they are likely to be related to the hydrocarbon-rich fluids venting on the seabed.     

Limnological instrumentation in the middle of the 19th century: the first temperature and density profiles measured in the Dead Sea

The first modern survey of the Dead Sea was performed by the Geological Survey of Israel in 1959–1960,and the report published remains the baseline study for our understanding of the physical and chemical properties of the lake.At the time the Dead Sea was a meromictic lake with a strong salinity gradient separating the deep waters(40 m depth) from the less saline surface waters.A few results of analyses of deeper water samples collected in the 1930 s were reported,but overall we have very little information about the structure of the lake's water column before the 1959–1960 survey.However,it is little known that data on the physical and the chemical structure of the Dead Sea water column were obtained already in the middle of the 19 th century,and the information collected then is highly relevant for the reconstruction of the limnological properties of the lake in earlier times.The expedition of Lieutenant William Lynch(U.S.Navy) in 1848 reported the presence of a temperature minimum at a depth of ~18 m,and also retrieved a water sample collected close to the bottom for chemical analysis.In 1864,the French Dead Sea exploration by the Duc de Luynes and his crew yielded detailed density and salinity profiles for a number of sampling stations.The results of these pioneering studies are discussed here,as well as the sampling equipment and measuring instruments used by the 1848 and the 1864 expeditions.     

Multiscale analysis of vegetation surface fluxes: from seconds to years

The variability in land surface heat (H), water vapor (LE), and CO₂ (or net ecosystem exchange, NEE) fluxes was investigated at scales ranging from fractions of seconds to years using eddy-covariance flux measurements above a pine forest. Because these fluxes significantly vary at all these time scales and because large gaps in the record are unavoidable in such experiments, standard Fourier expansion methods for computing the spectral and cospectral statistical properties were not possible. Instead, orthonormal wavelet transformations are proposed and used. The are ideal at resolving process variability with respect to both scale and time and are able to isolate and remove the effects of missing data (or gaps) from spectral and cospectral calculations. Using the spectra, we demonstrated unique aspects in three appropriate ranges of time scales: turbulent time scales (fractions of seconds to minutes), meteorological time scales (hour to weeks), and seasonal to interannual time scales corresponding to climate and vegetation dynamics. We have shown that: (1) existing turbulence theories describe the short time scales well, (2) coupled physiological and transport models (e.g. CANVEG) reproduce the wavelet spectral characteristics of all three land surface fluxes for meteorological time scales, and (3) seasonal dynamics in vegetation physiology and structure inject strong correlations between land surface fluxes and forcing variables at monthly to seasonal time scales. The broad implications of this study center on the possibility of developing low-dimensional models of land surface water, energy, and carbon exchange. If the bulk of the flux variability is dominated by a narrow band or bands of modes, and these modes “resonate” with key state and forcing variables, then low-dimensional models may relate these forcing and state variables to NEE and LE.     

Characterization of the halophilic archaeal community in saltern crystallizer ponds by means of polar lipid analysis

Saltern crystallizer ponds are coloured red due to the presence of dense communities of red halophilic archaea (family Halobacteriaceae). Little quantitative information exists on the species distribution within the archaeal community in such ponds. As the different genera of the Halobacteriaceae differ in polar lipid content, and especially in the types of glycolipids, lipid analysis can be used to obtain information on the nature of the organisms present. Analysis of the polar lipids extracted from the biomass collected from the saltern crystallizer ponds in Eilat, Israel, showed one major glycolipid to be present, co-chromatographing with the sulfated diglycosyl diether lipid characteristic of the genusHaloferax. No indications were found for the presence of significant amounts of those glycolipids that would indicate the presence of large numbers of other archaea such asHalobacterium species (H. cutirubrum andH. salinarium, characterized by sulfated triglycosyl and tetraglycosyl diethers), orHaloarcula species (possessing a triglycosyl diether). Phosphatidyl glycerosulfate, a polar lipid absent inHaloferax species, was present in the lipid extract from the crystallizer ponds, suggesting that the dominant microorganism present may be related to strains which are presently classified in the genusHalobacterium but are awaiting a taxonomic reappraisal (H. sodomense, H. saccharovorum, andH. trapanicum). Organisms of the latter group are characterized by sulfated diglycosyl diethers, and the presence of phosphatidyl glycerosulfate. Attempts to isolate the dominant type of bacterium on agar plates yielded relatively low counts (1–2 orders of magnitude lower than the numbers observed microscopically) of bacteria, and most of the isolates had a polar lipid composition characteristic of theH. salinarium group or theH. sodomense-H. saccharovorum-H. trapanicum group.     

The suburbanization of retail trade: a U.S. nationwide view

The Censuses of Business 1958, 1963 and 1967 and the Censuses of Retail Trade 1972 and 1977 provide data on retail sales in CBDs and major retail centers (MRCs) of SMSAs. Through this period sales in MRCs increased while CBDs lost, reflecting the decline in the population and income of central cities. However, MRCs grew faster until 1963 compared to the late sixties and seventies, due to the rapid diffusion of MRCs all over the country in the early sixties. Retail sales in CBDs continued to decline through the seventies. The trends of increase in MRC retail sales reflect several stages of suburbanization of population, and an increase in the ‘doughnut effect’.     

A multicriteria model for the location of solid waste transfer stations: The case of Ashdod,Israel

Solid waste transfer stations are designed in order to avoid the direct travelling of trucks from individual collection sites to refuse disposal sites. The location of such stations is problematic since they may have to be established within urban areas. There are five groups of locational consideration for transfer stations: Ecological, political, transportation, economic and spatial. The multicriteria evaluation model may be used for a comparative assessment of the many criteria involved. Each group of criteria and each specific criterion are ranked ordinally, and then proposed sites are rated according to each criterion. The final ranking summaries indicate the preferred location. The method was successfully applied to two stations in Ashdod, Israel.This paper is based on an unpublished MA thesis entitled Criteria for the location of solid waste transfer stations in Israel, by Y. Gil, supervised by A. Kellerman, Department of Geography, Bar-Ilan University, Ramat Gan, 1987 (Hebrew)     

INDUSTRIAL DEVELOPMENT AND ARAB-JEWISH ECONOMIC GAPS IN THE GALILEE REGION,ISRAEL1

Israel's development of industrial zones in the peripheral Galilee region is a major element of its national planning policy. The paper examines the economic impact of three of these industrial zones—Carmiel, Tefen, and Ma'alot—on Arabs and Jews in the region. Data on key employment and input and output indicators were collected through a survey of all firms in the three estates. In 1989 economic benefits generated by the three industrial zones were disproportionately enjoyed by the Jewish sector, thereby reinforcing patterns of interethnic economic gaps and minority dependence.