Seismology Applied to Shallow Zone Research

2009 ◽  
pp. 156-156-15
Author(s):  
Daniel Linehan
Keyword(s):  
Shallow Zone

scholarly journals Spatial distribution and survival rate of waterfrog tadpoles in relation to biotic and abiotic factors: a field experiment

2001 ◽  
Vol 22 (1) ◽  
pp. 21-32 ◽  
Author(s):  
Sylvie Thurnheer ◽  
Heinz-Ulrich Reyer
Keyword(s):  
Spatial Distribution ◽  
Community Dynamics ◽  
Abiotic Factors ◽  
Rana Esculenta ◽  
Natural Conditions ◽  
Major Purpose ◽  
Biotic And Abiotic Factors ◽  
Lab Experiments ◽  
Shallow Zone ◽  
Population And Community Dynamics

AbstractPredictions about population and community dynamics are usually based on lab experiments. Because the results are difficult to transfer to natural conditions, the major purpose of this study was to test the effects of biotic and abiotic factors on tadpole populations in a natural environment. We stocked six ponds, created the previous year, with known numbers of Rana esculenta and R. lessonae tadpoles and followed their development over several months. When compared among ponds, tadpole density correlated positively with the nitrate:phosphate ratio. This suggests that water chemistry may have affected survival, either directly or indirectly via productivity. Within ponds, both species showed a clear preference for the shallow zone. This behavior probably reflects a preference for warm water close to the surface, rather than avoidance of predators, because relative densities of odonates also increased from deep to shallow zones. This study is one of few that not only considers the distribution of the anuran tadpoles but the distribution of their predators as well.

Measurements of the Initial Ground Temperature in GSHP System

2014 ◽  
Vol 919-921 ◽  
pp. 1707-1715
Author(s):  
Ya Su Zhou ◽  
Wan Lan Ju ◽  
Zheng Liu
Keyword(s):  
Temperature Distribution ◽  
Small Difference ◽  
Engineering Application ◽  
Ground Temperature ◽  
Engineering Applications ◽  
Average Water Temperature ◽  
Arithmetic Average ◽  
Testing Method ◽  
Shallow Zone ◽  
The Mean

The initial ground temperature (IGT) is one of the most important parameters in designing a ground source heat pump (GSHP) system and evaluating its performance. In this paper, three initial ground temperature test methods are introduced. Except the shallow zone, the ground temperature distribution measured from direct and indirect testing method has very small difference. In direct test, the temperature sensor must be embedded when burying the tube in the borehole which is hard to operate in engineering applications. Thus the direct testing method is suggested to be applied in the scientific research. The indirect testing method could be used in engineering applications. The mean ground temperature could be calculated from temperature distribution except the shallow zone temperature. The results from three calculating methods have a quite small difference. Therefore, the arithmetic average method is suggested for scientific and engineering application to calculate the mean ground temperature. The mean ground temperature is also gotten in TRT conveniently. In the condition of velocity 0.7m/s, water was circulated in the tube system with no heat source for 30 minutes. The average water temperature could be regard as the mean ground temperature with sufficient accuracy.

scholarly journals DENSIDAD POBLACIONAL DE CUATRO ESPECIES DE ERIZO (ECHINODERMATA: ECHINOIDEA) EN EL ARRECIFE DE LA ENTREGA, OAXACA

2005 ◽  
Vol 20 (1-2) ◽  
pp. 65
Author(s):  
P. Zamorano ◽  
G. E. Leyte-Morales
Keyword(s):  
Population Density ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Depth Range ◽  
Deep Zone ◽  
Total Abundance ◽  
Subsequent Increase ◽  
Shallow Zone ◽  
Over Time ◽  
Shallow Part

De octubre de 2002 a agosto de 2003 se realizaron muestreos bimestrales de la abundancia de erizos en el arrecife de La Entrega. El arrecife fue dividido en dos profundidades (somero 0-6 m y profundo 6-12 m). En cada profundidad se realizaron seis transectos de 50 m de largo por 1 m de ancho. La mayor densidad anual correspondió a Diadema mexicanum (5.96±0.85 ind/m2), seguido de Eucidaris thouarsii (0.46±0.14 ind/m2); Echinometra vanbrunti y Toxopneustes roseus presentaron densidades bajas (0.03±0.01 ind/m2 y 0.02±0.01 ind/m2, respectivamente). Las cuatro poblaciones de erizos presentaron diferencias entre profundidades observándose mayor densidad en lo profundo; si consideramos la abundancia total de erizos en el arrecife, no se registraron diferencias temporales. Empero, al analizar por separado las profundidades, sólo E. thouarsii no presentó diferencias temporales en ambas profundidades. En diciembre, las densidades de D. mexicanum y E. thouarsii disminuyeron en lo profundo y aumentaron en lo somero, posiblemente porque sucedió una mortalidad coralina en lo somero del arrecife y el incremento de las algas motivó a estas especies a desplazarse a la parte dañada. Actualmente el arrecife de La Entrega se encuentra en avanzado estado de erosión lo que puede favorecer que la abundancia de erizos se incremente al igual que su actividad bioerosionadora. Population density of four species of sea urchin (Echinodermata: Echinoidea) at La Entrega Reef, Oaxaca Bimonthly samples of sea urchins fauna inhabiting the La Entrega Reef, Oaxaca, Mexico, were obtained from October 2002 to August 2003. The reef area was divided in two sampling zones, corresponding to shallow (0-6 m) and deep (6-12 m) water. Six transects of 50 m length by 1 m wide were sampled in each zone. Greatest annual density corresponded to Diadema mexicanum (5.96 ± 0.85 ind/m2),followed by Eucidaris thouarsii (0.46 ± 0.14 ind/m2); Echinometra vanbrunti and Toxopneustes roseus presented low densities (0.03 ± 0.01 indv/m2 and 0.02 ± 0.01 ind/m2, respectively). Density of the four populations varied considerably and higher densities were observed in the deep zone. Total abundance of sea urchins (shallow and deep samples) did not vary significantly over time. Abundance per depth range, however, was different over time for all species except for E. thouarsii. In December densities of D. mexicanum and E. thouarsii decreased in the deep zone and increased in the shallow zone, due to massive mortality of coral in the shallow part of the reef and to subsequent increase of algal coverage attracting these species to the shallowest part of the reef. The La Entrega reef is presently in an advanced state of erosion that could favor an increase of sea urchins abundance and of their bioerosion activity.

scholarly journals Peridotite and pyroxenite xenoliths from the Muskox kimberlite, northern Slave craton, Canada

2016 ◽  
Vol 53 (1) ◽  
pp. 41-58 ◽  
Author(s):  
David E. Newton ◽  
Maya G. Kopylova ◽  
Jennifer Burgess ◽  
Pamela Strand
Keyword(s):  
Partial Melting ◽  
Bulk Composition ◽  
Kimberlite Pipe ◽  
Spinel Peridotite ◽  
Small Scale ◽  
Local Effects ◽  
Slave Craton ◽  
Shallow Zone ◽  
Mantle Fluids ◽  
Peridotitic Mantle

We present petrography, mineralogy, and thermobarometry for 53 mantle-derived xenoliths from the Muskox kimberlite pipe in the northern Slave craton. The xenolith suite includes 23% coarse peridotite, 9% porphyroclastic peridotite, 60% websterite, and 8% orthopyroxenite. Samples primarily comprise forsteritic olivine (Fo 89–94), enstatite (En 89–94), Cr-diopside, Cr-pyrope garnet, and chromite spinel. Coarse peridotites, porphyroclastic peridotites, and pyroxenites equilibrated at 650–1220 °C and 23–63 kbar (1 kbar = 100 MPa), 1200–1350 °C and 57–70 kbar, and 1030–1230 °C and 50–63 kbar, respectively. The Muskox xenoliths differ from xenoliths in the neighboring and contemporaneous Jericho kimberlite by their higher levels of depletion, the presence of a shallow zone of metasomatism in the spinel peridotite field, a higher proportion of pyroxenites at the base of the mantle column, higher Cr2O3 in all pyroxenite minerals, and weaker deformation in the Muskox mantle. We interpret these contrasts as representing small-scale heterogeneities in the bulk composition of the mantle, as well as the local effects of interaction between metasomatizing fluid and mantle wall rocks. We suggest that asthenosphere-derived pre-kimberlitic melts and fluids percolated less effectively through the less permeable Muskox mantle, resulting in lower degrees of hydrous weakening, strain, and fertilization of the peridotitic mantle. Fluids tended to concentrate and pool in the deep mantle, causing partial melting and formation of abundant pyroxenites.

Mobility of Ra-226 and Heavy Metals (U, Th and Pb) From Pyritic Uranium Mine Tailings Under Sub-Aqueous Disposal Conditions

2011 ◽  
Author(s):  
Nand K. Dave´
Keyword(s):  
Heavy Metals ◽  
Surface Water ◽  
Mine Tailings ◽  
Ion Concentration ◽  
Uranium Mine ◽  
Acid Generation ◽  
Shallow Zone ◽  
Acidic Conditions ◽  
Waste Repositories

Laboratory lysimeter studies were undertaken to evaluate the leaching characteristics and mobility of Ra-226 and other heavy metals (U, Th and Pb) from pyritic uranium mine tailings under sub-aqueous disposal conditions for assessing the long-term radiological stability of such waste repositories. The experiments were conducted using three types of un-oxidized tailings: fine, coarse and gypsum depleted mill total tailings. The results showed that Ra-226 was leached from surface of the submerged tailings and released to both surface water and shallow zone pore water during initial low sulphate ion concentration of the surface water cover in all three cases. The release of Ra-226 was further enhanced with the onset of weak acidic conditions in the surface water covers of both coarse and gypsum depleted mill total tailings. With additional acid generation and increasing sulphate and iron concentrations, the dissolved Ra-226 concentrations in the water covers of these tailings gradually decreased back to low levels. Pb was also leached and mobilized with the development of moderate acidic conditions at the surface of the submerged coarse and gypsum deplete tailings. No leaching of U and Th was observed.

THE ORIGIN OF HYDROCHEMICAL PATTERNS IN HUMMOCKY MORAINE

1967 ◽  
Vol 4 (6) ◽  
pp. 1065-1092 ◽  
Author(s):  
A. Rozkowski
Keyword(s):  
Groundwater Flow ◽  
Flow Model ◽  
Chemical Analyses ◽  
Soluble Salts ◽  
Recharge Area ◽  
Discharge Area ◽  
Transmission Zone ◽  
Significant Enrichment ◽  
Poorly Soluble ◽  
Shallow Zone

Hydrochemical investigations were carried out in a small local basin in hummocky moraine of southern Saskatchewan. The 'basin' consisted of a hill and surrounding permanent sloughs. The constructed Teledeltos flow model shows the typical pattern of groundwater flow near permanent lakes, where the hills are areas of recharge and the sloughs areas of discharge. Based on the chemical analyses of soil and till extracts as well as on the chemical analyses of slough and groundwater, the development of certain hydrochemical patterns in hummocky moraine can be explained.Three hydrochemical zones can be distinguished: SO4–Ca–Mg in the recharge area, SO4–Mg–Ca in the transmission zone, and SO4–Mg–(Na) in the discharge area. The increase of groundwater salinity from the recharge area to the discharge area is due to evapotranspiration as well as to the poor permeability of the glacial deposits.The SO4–Mg–Ca type of water of the recharge area is already formed in the zone of aeration. The subsequent changes of groundwater chemistry in the zone of saturation are induced by the enrichment of easily soluble salts and by the steady precipitation of poorly soluble salts. The sharp increase in salinity and the significant enrichment of the SO4–Mg type of water by easily soluble salts take place in the shallow zone of the discharge area close to the surface. The study of water extracts suggests the presence of groundwater discharge in the region of the capillary fringe of the recharge area also.The delivery of ions to the sloughs takes place by groundwater flow and inter-flow; therefore, the hydrochemistry of sloughs is primarily determined by the chemistry of these waters. The further metamorphosis of slough water is produced mainly by intensive evaporation as well as by ion exchange within the slough.

Relationship between sinking organic matter and minerals in the shallow zone of the western Subarctic Pacific

2010 ◽  
Vol 66 (5) ◽  
pp. 697-708 ◽  
Author(s):  
Masahito Shigemitsu ◽  
Yutaka W. Watanabe ◽  
Yasuhiro Yamanaka ◽  
Hajime Kawakami ◽  
Makio C. Honda
Keyword(s):  
Organic Matter ◽  
Subarctic Pacific ◽  
Western Subarctic Pacific ◽  
Shallow Zone
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