Socio-structural forces predicting global water footprint: socio-hydrology and ecologically unequal exchange     

Md Belal Hossain  Angela G. Mertig 《水文科学杂志》2020,65(4):495-506

ABSTRACT

Growth in water use and threatened shortages of water have become increasingly important in the modern world system. Natural resources are exploited extensively by capitalist interests in industrially advanced nations, while the lower strata of the world system, the underdeveloped societies, are left with limited access to natural resources for their productive processes, particularly water resources. We contribute to socio-hydrological research by examining underlying socio-structural factors that play a part in the process of deteriorating conditions of global water resources. Drawing on a world-systems perspective, this study examines how socio-structural forces – world-system position, per capita beef consumption, per capita energy consumption, and urbanization – affect per capita water footprint, which includes an accounting of “virtual water” consumption. We find that per capita beef consumption and per capita energy consumption have significant positive direct effects, and the world-system position has a significant indirect and total effect on per capita water footprint.  相似文献   

Application of the grid square technique to mapping of evapotranspiration     

Angela M. Foyster 《Journal of Hydrology》1973,19(3):205-226

A grid-based technique for mapping potential evapotranspiration is described. An attempt is made to extrapolate the constituent parameters of Penman's equation (1962) over a grid, so that the equation can be evaluated for every grid square. Data for a part of Southwest England are used to demonstrate the technique. Aspect and slope, which determine evaporation to a considerable degree, have been included using a formula derived by Okanoue.  相似文献   

Speciation and role of iron in cloud droplets at the puy de Dôme station     

Marius Parazols  Angela Marinoni  Pierre Amato  Otman Abida  Paolo Laj  Gilles Mailhot 《Journal of Atmospheric Chemistry》2006,54(3):267-281

Iron is the most abundant transition metal in the atmosphere and can play a significant role in cloudwater chemistry where its reactivity is closely related to the partitioning between Fe(II) and Fe(III). The objective of this work is to determine the total iron content and the iron speciation in a free tropospheric site, and to understand which factors influence these parameters. We collected 147 samples of cloudwater during 34 cloud events over a period of four years at the puy de Dôme summit. Besides iron we measured other chemical compounds, solar radiation, physico-chemical and meteorological parameters potentially connected with iron reactivity. The total iron concentrations ranged from 0.1 to 9.1 μM with the major frequency occurring at low levels. The pH and presence of organic complexants seem to be the most significant factors connected with total dissolved iron; while the iron oxidation state seems to be an independent factor. Light intensity, presence of complexants or oxidants (H₂O₂) do not influence the Fe(II)/Fe(Total) ratio, that was quite constant at about 0.75. This could be due to the potential redox that forces the Fe(II)-Fe(III) couple to the reduced form or, more probably to the complexation by Natural Organic Matter, that can stabilize iron in its reduced form and prevent further oxidation. Our field measurements did not show the diurnal cycle observed in surface water and predicted by models of atmospheric chemistry. This result prompts a more careful review of the role of iron and, by analogy, all the transition metals in atmospheric liquid phase, often over-estimated in the literature.  相似文献   

A Wetland Simulation Module for the MODFLOW Ground Water Model   总被引：8，自引：0，他引：8  

Jorge I. Restrepo  Angela M. Montoya  Jayantha Obeysekera 《Ground water》1998,36(5):764-770

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Absolute dating by uranium series disequilibrium of bones from the cave of La Chaise-de-Vouthon (Charente), France     

Angela M. Rae  Miro Ivanovich  Henry P. Schwarcz 《地球表面变化过程与地形》1987,12(5):543-550

Animal bones, associated with Palaeolithic artefacts and skeletal remains of early hominids from the cave of La Chaise-de-Vouthon, have been dated using a new approach to uranium series dating of bone. Speleothem (cave calcite) interstratified with bone-bearing sediments in the two chambers of Grotte Bourgeois-Delaunay and Grotte Suard have previously been dated by the ²³⁰Th/²³⁴ U method. This provides a chronological control for the bone ages, for which the method is still at an experimental stage. A good agreement is shown in most cases between the calcite and the bone ages, showing the cave to have been a stable environment for the deposition of bone and the acquisition of uranium.  相似文献   

Origin and significance of 13-hydroxychlorophyll derivatives in sediments     

J Stuart Walker  Angela H Squier  Dominic A Hodgson  Brendan J Keely   《Organic Geochemistry》2002,33(12)

The authenticity of hydroxychlorophyll derivatives in sediments has been verified by subjecting pure chlorophyll preparations to the extraction method used for sediments. Model studies of chlorophyll autoxidation reveal hydroxychlorophyll as the major product formed in the presence of hydrogen peroxide. Its stability to further oxidation implies that hydroxychlorophyll derivatives are not precursors of aetioporphyrins and are more likely to produce cycloalkanoporphyrins via the processes of diagenesis. The occurrence of 13²-hydroxyphaeophytin a throughout a sediment core from Loch Ness confirms it to be a widespread chlorophyll oxidation product formed during early diagenesis. Profiles of hydroxychlorophyll derivatives in a sediment core from an Antarctic lake demonstrate their potential for use as markers of oxidation processes in palaeoenvironmental assessment.  相似文献   

The dual isotopes of deep nitrate as a constraint on the cycle and budget of oceanic fixed nitrogen   总被引：1，自引：0，他引：1  

Daniel M. Sigman  Peter J. DiFiore  Mathis P. Hain  Curtis Deutsch  Yi Wang  David M. Karl  Angela N. Knapp  Moritz F. Lehmann  Silvio Pantoja 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(9):1419-1439

We compare the output of an 18-box geochemical model of the ocean with measurements to investigate the controls on both the mean values and variation of nitrate δ¹⁵N and δ¹⁸O in the ocean interior. The δ¹⁸O of nitrate is our focus because it has been explored less in previous work. Denitrification raises the δ¹⁵N and δ¹⁸O of mean ocean nitrate by equal amounts above their input values for N₂ fixation (for δ¹⁵N) and nitrification (for δ¹⁸O), generating parallel gradients in the δ¹⁵N and δ¹⁸O of deep ocean nitrate. Partial nitrate assimilation in the photic zone also causes equivalent increases in the δ¹⁵N and δ¹⁸O of the residual nitrate that can be transported into the interior. However, the regeneration and nitrification of sinking N can be said to decouple the N and O isotopes of deep ocean nitrate, especially when the sinking N is produced in a low latitude region, where nitrate consumption is effectively complete. The δ¹⁵N of the regenerated nitrate is equivalent to that originally consumed, whereas the regeneration replaces nitrate previously elevated in δ¹⁸O due to denitrification or nitrate assimilation with nitrate having the δ¹⁸O of nitrification. This lowers the δ¹⁸O of mean ocean nitrate and weakens nitrate δ¹⁸O gradients in the interior relative to those in δ¹⁵N. This decoupling is characterized and quantified in the box model, and agreement with data shows its clear importance in the real ocean. At the same time, the model appears to generate overly strong gradients in both δ¹⁸O and δ¹⁵N within the ocean interior and a mean ocean nitrate δ¹⁸O that is higher than measured. This may be due to, in the model, too strong an impact of partial nitrate assimilation in the Southern Ocean on the δ¹⁵N and δ¹⁸O of preformed nitrate and/or too little cycling of intermediate-depth nitrate through the low latitude photic zone.  相似文献   

Investigation of the protein osteocalcin of Camelops hesternus: Sequence, structure and phylogenetic implications     

James F. Humpula  Hasand Gandhi  Angela K. Walker  James J. Smith  R. George Corner 《Geochimica et cosmochimica acta》2007,71(24):5956-5967

Ancient DNA sequences offer an extraordinary opportunity to unravel the evolutionary history of ancient organisms. Protein sequences offer another reservoir of genetic information that has recently become tractable through the application of mass spectrometric techniques. The extent to which ancient protein sequences resolve phylogenetic relationships, however, has not been explored. We determined the osteocalcin amino acid sequence from the bone of an extinct Camelid (21 ka, Camelops hesternus) excavated from Isleta Cave, New Mexico and three bones of extant camelids: bactrian camel (Camelus bactrianus); dromedary camel (Camelus dromedarius) and guanaco (Llama guanacoe) for a diagenetic and phylogenetic assessment. There was no difference in sequence among the four taxa. Structural attributes observed in both modern and ancient osteocalcin include a post-translation modification, Hyp₉, deamidation of Gln₃₅ and Gln₃₉, and oxidation of Met₃₆. Carbamylation of the N-terminus in ancient osteocalcin may result in blockage and explain previous difficulties in sequencing ancient proteins via Edman degradation.A phylogenetic analysis using osteocalcin sequences of 25 vertebrate taxa was conducted to explore osteocalcin protein evolution and the utility of osteocalcin sequences for delineating phylogenetic relationships. The maximum likelihood tree closely reflected generally recognized taxonomic relationships. For example, maximum likelihood analysis recovered rodents, birds and, within hominins, the Homo-Pan-Gorilla trichotomy. Within Artiodactyla, character state analysis showed that a substitution of Pro₄ for His₄ defines the Capra-Ovis clade within Artiodactyla. Homoplasy in our analysis indicated that osteocalcin evolution is not a perfect indicator of species evolution. Limited sequence availability prevented assigning functional significance to sequence changes. Our preliminary analysis of osteocalcin evolution represents an initial step towards a complete character analysis aimed at determining the evolutionary history of this functionally significant protein. We emphasize that ancient protein sequencing and phylogenetic analyses using amino acid sequences must pay close attention to post-translational modifications, amino acid substitutions due to diagenetic alteration and the impacts of isobaric amino acids on mass shifts and sequence alignments.  相似文献   

The EU Directive on port reception facilities for ship-generated waste and cargo residues: the results of a second survey on the provision and uptake of facilities in North Sea ports     

Carpenter A  Macgill SM 《Marine pollution bulletin》2005,50(12):1541-1547

The aim of this paper is to evaluate the results of a survey of the availability and uptake of port reception facilities within the North Sea area. The evaluation is based primarily on original survey data from the autumn of 2002 which followed on from a similar survey conducted in the summer of 2000. The EU Directive on port reception facilities for ship-generated waste etc. (Directive 2000/59/EC) was due to enter into force in December 2002, and required all EU ports to provide reception facilities to meet the needs of the vessels normally calling in at them. This paper examines the readiness of North Sea ports to meet that requirement and also considers the actual uptake levels of facilities, where ports were able to provide such information.  相似文献   

A Nondestructive Technique for Predicting the In Situ Void Ratio for Marine Sediments     

Dei G. Huws  Angela M. Davis  James R. Pyrah 《Marine Georesources & Geotechnology》2000,18(4):333-346

This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner.  相似文献