Field-Scale Investigation of Infiltration Into a Compacted Soil Liner     

Samuel V. Panno  Beverly L. Herzog  Keros Cartwright  Kenneth R. Rehfeldt  Ivan G. Krapac  Bruce R. Hensel 《Ground water》1991,29(6):914-921

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Distributional patterns of blue crabs (Callinectes sp.) in a tropical estuarine lagoon     

Beverly A. Buchanan  Allan W. Stoner 《Estuaries and Coasts》1988,11(4):231-239

A two-year trawl study of Laguna Joyuda, Puerto Rico, a small, polyhaline lagoon with restricted oceanic exchange, yielded 803 crabs belonging to sixCallinectes species.Callinectes danae was the most abundant (35.7%), followed byC. sapidus (21%),C. ornatus (12.6%),C. bocourti (12.1%),C. exasperatus (1.2%), andC. larvatus (0.4%). Abundances of different species differed more spatially than temporally despite very homogeneous salinities.Callinectes bocourti andC. sapidus were most abundant furthest from the lagoon’s inlet, whileC. danae andC. ornatus were most abundant near the inlet and in the center of lagoon. Juveniles were least abundant in the center of the lagoon. Size frequencies of most species showed common trends with high percentages of small crabs furthest from the inlet, and high percentages of larger crabs near the inlet and central parts of the lagoon. Distributional patterns appear to be a result of complex interactions of habitat preferences and intra- and interspecific interactions among the crabs.  相似文献   

The nature and fate of natural resins in the geosphere--VIII. NMR and Py-GC-MS characterization of soluble labdanoid polymers, isolated from Holocene class I resins     

David J. Clifford  Patrick G. Hatcher  Robert E. Botto  John V. Muntean  Beverly Michels  Ken B. Anderson 《Organic Geochemistry》1997,27(7-8)

Soluble polylabdanoids isolated by sequential solvent extraction have been characterized by liquid-state ¹³C- and ¹H NMR and ¹³C-¹H HMQC (heteronuclear correlation) NMR spectroscopy in addition to solid-state NMR and Py-GC-MS techniques. Two Holocene resins originating from Santander, Colombia and Mombasa, Kenya were analyzed. Soluble polymers were isolated by extraction with a 1:1 (v/v) methylene chloride-methanol mixture following sequential extractions with methylene chloride and methanol. The molecular weight of polymer extracts was shown by GPC analyses to exceed that of non-polymeric occluded terpenoids. Py-GC-MS, solid-state ¹³C CP/MAS and ¹³C cross-polarization/depolarization NMR spectroscopy results indicated that chemical compositions of soluble polymers isolated from immature resins are highly representative of the structure of corresponding insoluble polymers, i.e. polylabdatrienes. These data provide evidence for cross-linking or cyclization of side-chain olefinic carbons during or shortly after polymerization. Generally, the characterization of soluble resin polymers by liquid-state NMR spectroscopy has proven to be an excellent means for investigating the maturation mechanism of polylabdanoid resinites, and has potential for furthering the application of Class I resinites as geothermal indicators.  相似文献   

Effects of toxic chemicals on macrophage phagocytosis in two estuarine fishes     

Beverly Anne Weeks  J.Ernest Warinner 《Marine environmental research》1984,14(1-4)

The phagocytic efficiency of macrophages isolated from the kidney of spot, Leiostomus xanthurus, and hogchoker, Trinectes maculatus, was determined in fish captured from the Elizabeth River (Virginia) Macrophage phagocytosis was found to be markedly reduced in the Elizabeth River fish as compared to Ware River controls. The macrophage phagocytic activity of Elizabeth River fish returned to normal after the fish were held in clean water for several weeks. This indicates that the decreased phagocytic activity was related to exposure to Elizabeth River pollutants but may be reversible.  相似文献   

Droughts in the desert: Medieval Warm Period associated with coarse sediment layers in the Gulf of Aqaba-Eilat,Red Sea     

Akos Kalman  Timor Katz  Paul Hill  Beverly Goodman-Tchernov 《Sedimentology》2020,67(6):3152-3166

Prolonged droughts can cause environmental stress, even in ecosystems that are already adapted to dry conditions. In these areas life greatly depends on rare, sporadic rainfall events that can produce flash floods. Today, urban expansion, population growth and development are occurring worldwide, including along hyperarid coastlines, an ecological zone on the extreme of habitability. In such places, the absence of the already limited precipitation can lead to long-lasting damage, and recognizing drought conditions in the past is useful for planning. Recognizing droughts, however, is challenging because they are not known as depositional events, and therefore may be under-recognized in the sedimentological record. Floods in these hyperarid deserts carry eroded sediments and deposit them in either terrestrial or marine terminal basins. In the hyperarid (ca 30 mm rain per year) desert surrounding the northern Gulf of Aqaba-Eilat some flash floods reach the sea and deposit alluvial sediments (mostly silt and clay) on the shelf. Following a recent 17 year drought period (1995 to 2012) a coarser surface layer was recognized offshore the outlet of an ephemeral river, despite the lack of incoming flood material. This coarsened layer resulted from a prolonged period wherein mixing and winnowing of fine particles at the surface was not interrupted by recurrent flash floods. In the bottom of two sediment cores collected from the same shelf, a similarly coarsened layer was observed. The terminal level of this deep coarse layer was dated to ca 660 yr bp , corresponding with the end of the Medieval Warm Period (ca 1350 ad ). These findings suggest that the medieval anomaly resulted in a prolonged drought period in this already arid region. These results present a new interpretation of grain-size distribution records that provides a means to reconstruct drought histories in hyperarid regions globally.  相似文献   

Historical analogues of the recent extreme minima observed in the Atlantic meridional overturning circulation at 26°N     

Adam T. Blaker  Joël J.-M. Hirschi  Gerard McCarthy  Bablu Sinha  Sarah Taws  Robert Marsh  Andrew Coward  Beverly de Cuevas 《Climate Dynamics》2015,44(1-2):457-473

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Wildfire evacuations in Canada 1980–2007     

Beverly  Jennifer L.  Bothwell  Peter 《Natural Hazards》2011,59(1):571-596

Evacuations represent an integral aspect of protecting public safety in locations where intense, fast-spreading forest fires co-occur with human populations. Most Canadian fire management agencies have as their primary objective the protection of people and property, and all fire management agencies in Canada recommend evacuations when public safety is in question. This study provides the first national assessment of wildfire-related evacuations in Canada and documents the loss of homes that coincided with evacuation events. The most striking finding is that despite the intensity and abundance of wildfire in Canada, wildfires have displaced a relatively small number of people. Between 1980 and 2007, the median number of evacuees and home losses per year in Canada were 3,590 and 2, respectively. Evacuees’ homes survived in 99.3% of cases. Patterns of evacuations and home losses reflected the distributions of forests, wildfire, and people across the Canadian landscape. Most evacuations occurred in boreal areas, which have relatively low population densities but among the highest percent annual area burned in Canada. Evacuations were less common in southern parts of the country, where most Canadians reside, but individual wildfires in these areas had significant impacts. Interactions between wildfire and people in Canada exhibited a unique regional pattern, and within the most densely populated regions of the country they can be considered ‘low-probability, high-consequence’ events. This Canadian context is fundamentally different from places such as California, where concentrations of fires and people overlap across large areas and therefore calls for a fundamentally different fire management response.  相似文献   

US Coastal Plains Marine Center     

Beverly C. Snow 《Marine Policy》1978,2(3):234-235

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Biogeochemistry of Fe(II) oxidation in a photosynthetic microbial mat: Implications for Precambrian Fe(II) oxidation     

Robert E. Trouwborst  Gretchen Koch  Beverly K. Pierson 《Geochimica et cosmochimica acta》2007,71(19):4629-4643

We studied the role of microbial photosynthesis in the oxidation of Fe(II) to Fe(III) in a high Fe(II) and high Mn(II) hot spring devoid of sulfide and atmospheric oxygen in the source waters. In situ light and dark microelectrode measurements of Fe(II), Mn(II) and O₂ were made in the microbial mat consisting of cyanobacteria and anoxygenic photosynthetic Chloroflexus sp. We show that Fe(II) oxidation occurred when the mat was exposed to varying intensities of sunlight but not near infrared light. We did not observe any Mn(II) oxidation under any light or dark condition over the pH range 5-7. We observed the impact of oxygenic photosynthesis on Fe(II) oxidation, distinct from the influence of atmospheric O₂ and anoxygenic photosynthesis. In situ Fe(II) oxidation rates in the mats and cell suspensions exposed to light are consistent with abiotic oxidation by O₂. The oxidation of Fe(II) to form primary Fe(III) phases contributed to banded iron-formations (BIFs) during the Precambrian. Both oxygenic photosynthesis, which produces O₂ as an oxidizing waste product, and anoxygenic photosynthesis in which Fe(II) is used to fix CO₂ have been proposed as Fe(II) oxidation mechanisms. Although we do not know the specific mechanisms responsible for all Precambrian Fe(II) oxidation, we assessed the relative importance of both mechanisms in this modern hot spring environment. In this environment, cyanobacterial oxygen production accounted for all the observed Fe(II) oxidation. The rate data indicate that a modest population of cyanobacteria could have mediated sufficient Fe(II) oxidation for some BIFs.  相似文献   

Impact of partial steps and momentum advection schemes in a global ocean circulation model at eddy-permitting resolution   总被引：4，自引：6，他引：4  

Barnier Bernard  Gurvan Madec  Thierry Penduff  Jean-Marc Molines  Anne-Marie Treguier  Julien Le Sommer  Aike Beckmann  Arne Biastoch  Claus Böning  Joachim Dengg  Corine Derval  Edmée Durand  Sergei Gulev  Elizabeth Remy  Claude Talandier  Sébastien Theetten  Mathew Maltrud  Julie McClean  Beverly De Cuevas 《Ocean Dynamics》2006,56(5-6):543-567

Series of sensitivity tests were performed with a z-coordinate, global eddy-permitting (1/4°) ocean/sea-ice model (the ORCA-R025 model configuration developed for the DRAKKAR project) to carefully evaluate the impact of recent state-of-the-art numerical schemes on model solutions. The combination of an energy–enstrophy conserving (EEN) scheme for momentum advection with a partial step (PS) representation of the bottom topography yields significant improvements in the mean circulation. Well known biases in the representation of western boundary currents, such as in the Atlantic the detachment of the Gulf Stream, the path of the North Atlantic Current, the location of the Confluence, and the strength of the Zapiola Eddy in the south Atlantic, are partly corrected. Similar improvements are found in the Pacific, Indian, and Southern Oceans, and characteristics of the mean flow are generally much closer to observations. Comparisons with other state-of-the-art models show that the ORCA-R025 configuration generally performs better at similar resolution. In addition, the model solution is often comparable to solutions obtained at 1/6 or 1/10° resolution in some aspects concerning mean flow patterns and distribution of eddy kinetic energy. Although the reasons for these improvements are not analyzed in detail in this paper, evidence is shown that the combination of EEN with PS reduces numerical noise near the bottom, which is likely to affect current–topography interactions in a systematic way. We conclude that significant corrections of the mean biases presently seen in general circulation model solutions at eddy-permitting resolution can still be expected from the development of numerical methods, which represent an alternative to increasing resolution.  相似文献