Influence of water temperature and salinity on seasonal occurrences of Vibrio cholerae and enteric bacteria in oyster-producing areas of Veracruz, México

The influence of temperature and salinity on the occurrence of Vibrio cholerae, Escherichia coli and Salmonella spp. associated with water and oyster samples was investigated in two lagoons on the Atlantic Coast of Veracruz, Mexico over a 1-year period. The results indicated that seasonal salinity variability and warm temperatures, as well as nutrient influx, may influence the occurrence of V. cholera. non-O1 and O1. The conditions found in the Alvarado (31.12 °C, 6.27‰, pH = 8.74) and La Mancha lagoons (31.38 °C, 24.18‰, pH = 9.15) during the rainy season 2002 favored the occurrence of V. cholera O1 Inaba enterotoxin positive traced in oysters. Vibrio alginolyticus was detected in Alvarado lagoon water samples during the winter season. E. coli and Salmonella spp. were isolated from water samples from the La Mancha (90–96.7% and 86.7–96.7%) and Alvarado (88.6–97.1% and 88.6–100%) lagoons. Occurrence of bacteria may be due to effluents from urban, agricultural and industrial areas.     

Theoretic analysis on phase delay phenomena of well water level tide in the double medium aquifer model

Introduction The phenomenon of water level tide was discovered at Duchort diggings, Czech in 1879. By 1939, Theis, an America hydrogeologist, confirmed that periodical wave of the well water level is caused by the solid tide. In 1964, Melchior, a Belgium geophysist, began to make research on this phenomenon. Then Cooper (1965), Bredehoeft (1967) and WANG, et al (1988) followed. In China the study on water level tide began with 1970s, and the study on well water level phase lagging began …     

Influence of the modified global ocean tide model with local tides of East and South China Seas on load gravity in China and its neighbor area

Introduction With the development of science and technology, the accuracy of gravity measurement is im-proved. The gravity observation with FG5 gravimeter has reached accuracy of μ magnitude. And the high accurate superconducting gravimeter can detect the tiny signal of 10?2 μ magnitude in frequency domain. With the high-accuracy gravity observation on Earth′s surface, the Earth′s tidal parameters can be determined precisely. And the observations can also be used to invert the struc-ture…     

Can plankton communities be considered as bio-indicators of water quality in the Lagoon of Venice?

This study examines whether plankton of the Lagoon of Venice could be considered as a bio-indicator of areas subjected to various anthropogenic influences. This study was a two year hydrochemical and biological survey in five areas of the Lagoon of Venice, each with different environmental conditions due to pollution from urban, industrial, thermal and agricultural wastes. Phytoplankton associations did not show any promising species. In the different lagoonal areas, this community was differentiated into its major groups. In contrast, the copepod Acartia tonsa Dana could be considered as a target species in highly eutrophic areas.     

Influence of sea surface wind wave turbulence upon wind-induced circulation, tide–surge interaction and bed stress

A three-dimensional finite volume unstructured mesh model of the west coast of Britain, with high resolution in the coastal regions, is used to investigate the role of wind wave turbulence and wind and tide forced currents in producing maximum bed stress in the eastern Irish Sea. The spatial distribution of the maximum bed stress, which is important in sediment transport problems, is determined, together with how it is modified by the direction of wind forced currents, tide–surge interaction and a surface source of wind wave turbulence associated with wave breaking. Initial calculations show that to first order the distribution of maximum bed stress is determined by the tide. However, since maximum sediment transport occurs at times of episodic events, such as storm surges, their effects upon maximum bed stresses are examined for the case of strong northerly, southerly and westerly wind forcing. Calculations show that due to tide–surge interaction both the tidal distribution and the surge are modified by non-linear effects. Consequently, the magnitude and spatial distribution of maximum bed stress during major wind events depends upon wind direction. In addition calculations show that a surface source of turbulence due to wind wave breaking in shallow water can influence the maximum bed stress. In turn, this influences the wind forced flow and hence the movement of suspended sediment. Calculations of the spatial variability of maximum bed stress indicate the level of measurements required for model validation.     

Influence of attenuation and site on microearthquakes’ spectra in Shillong region, of Northeast, India: A case study

We examine the influence of attenuation and site on the spectra of microearthquakes having origin within the Shillong region. The ratios of spectral amplitudes at lower and higher frequencies are measured for three different stations at varying epicentral distances to estimate Q value for both P- and S-wave in near and sub-surface layer. The average estimates of Q _P and Q _S are found to be 178 and 195. The ratio of Q _S to Q _P emerges to be greater than unity in major parts of the Shillong area, suggesting dominance of dry crust prevailing in Shillong region. The variation in corner frequencies for these spectra is inferred to be characteristics of the site. Besides, the disparity in spectral content with reference to hard rock site yields the inference that the incoming seismic signals get amplified considerably while traversing from southern part to northeastern part of Shillong, best outlined at 2 to 5 Hz, which is well corroborated by the existing lithology.     

Preliminary study on variation characteristics of ocean tide dynamic stress in crust and its relationship with earthquakes

~~Preliminary study on variation characteristics of ocean tide dynamic stress in crust and its relationship with earthquakes@陆明勇$China Center for Earthquake Disaster Emergency and SAR,Beijing 100049,China @郑文衡$Huazhong University of Science and Technology,Wuhan 430074,China①Strong earthquake catalogues in China. Earthquake catalogues reported monthly by Center for Analysis and Prediction, CEA. ①YI Zhi-gang. Institute of Crustal Dynamics, China Earthquake Administrati…     

Hydrological and water quality assessment of the Aghien Lagoon hydrosystem (Abidjan,Côte d’Ivoire)

ABSTRACT

To face the difficulties involved in supplying freshwater to Abidjan (Côte d’Ivoire), the Aghien Lagoon connected by a channel to the Potou-Ébrié lagoon is a potential resource for production of drinking water. A hydro-meteorological network was installed with the objective of assessing the sustainability of the lagoon in terms of both quantity and quality, and 10 sampling campaigns were conducted between June 2015 and December 2016 to evaluate the water quality. Even if the annual flow of the two peri-urban tributaries is just equivalent to the volume of the lagoon, the large daily inflow by the channel can secure the future quantitative demand. Unfortunately, the main tributaries in the peri-urban zones have lacked sanitation services and present numerous markers of pollution. Even if the water quality status of the lagoon remains quite good with respect to total nitrogen and total phosphorus, it nevertheless presents a high potential risk of eutrophication.     

Frequency-dependent attenuation of P and S waves in Yunnan region

Introduction Attenuation parameter Q~(-1) is an important factor for understanding the physical mechanism of seismic wave attenuation in relation to the composition and physical condition of the Earth′s interior (Sato, 1992) and it is also an indispensable parameter for the quantitative prediction of strong ground motion from the viewpoint of engineering seismology. Hence numerous studies of Q~(-1) have been carried out worldwide by using different methods and concentrate on seismically acti…     

Influence of SOI, DMI and Niño3.4 on South Australian rainfall

The influences of climate drivers (SOI, DMI and Niño3.4) on South Australian (SA) rainfall are investigated in this study. Recent records of monthly rainfall and climate driver index values from 1981 to 2010 were analysed for 53 rainfall stations, located across eight SA natural resources management (NRM) regions. The Pearson, Kendall and Spearman correlation tests were applied between rainfall and climate drivers and between the climate drivers themselves. Both SA summer (December to February) and autumn (March to May) rainfalls were found not significantly influenced by climate indices. Winter rainfall in the south and east parts of SA was found strongly influenced by both SOI and DMI, particularly in July and August. Both SOI and DMI are inter-correlated in winter. Spring rainfall was found significantly influenced by DMI in the south and east parts of SA, particularly in September and October. In terms of ENSO phenomena, whilst both SOI and Niño3.4 are correlated, SOI was found more to be influential than Niño3.4 for SA winter and spring rainfall. Outcomes of the study are useful for stochastic rainfall generation and for developing downscaling techniques to generate rainfall projections in the region.     

Influence of uncertainty in delimitation of seismic statistical zone on results of PSHA

The seismic hazard of research area is evaluated by probabilistic analysis method for three different seismic statistical zone scenarios.The influence of uncertainty in seismic statistical zone delimiting on the evaluation result is discussed too.It can be seen that for those local sites along zone‘s border or within areas with vast change of upper bound magnitude among different scenarios the influence on seismic hazard result should not be neglected.     

Effect of water stress on ecosystem photosynthesis and respiration of a Leymus chinensis steppe in Inner Mongolia

Many studies on global climate have forecast major changes in the amounts and spatial patterns of precipitation that may significantly affect temperate grasslands in arid and semi-arid regions. As a part of ChinaFLUX, eddy covariance flux measurements were made at a semi-arid Leymus chinensis steppe in Inner Mongolia, China during 2003-2004 to quantify the response of carbon exchange to environmental changes. Results showed that gross ecosystem production (FGEP) and ecosystem respiration (Reco) of the steppe were significantly depressed by water stress due to lack of precipitation during the growing season. Temperature was the dominant factor affecting FGEP and Reco in 2003, whereas soil moisture imposed a significant influence on both Reco and FGEP in 2004. Under wet conditions, Reco showed an exponentially increasing trend with temperature (Q10 = 2.0), but an apparent reduction in the value of Reco and its temperature sensitivity were observed during the periods of water stress (Q10=1.6). Both heat and water stress can cause decrease in FGEP. The sea-sonality of ecosystem carbon exchange was strongly correlated with the variation of precipitation. With less precipitation in 2003, the steppe sequestrated carbon in June and July, and went into a senescence in early August due to water stress. As compared to 2003, the severe drought during the spring of 2004 delayed the growth of the steppe until late June, and the steppe became a CO2 sink from early July until mid-September, with ample precipitation in August. The semi-arid steppe released a total of 9.7 g C·m-2 from May 16 to the end of September 2003, whereas the net carbon budget during the same period in 2004 was close to zero. Long-term measurements over various grasslands are needed to quantify carbon balance in temperate grasslands.     

Attenuation characteristics of coda waves and estimation of Qc values in eastern China

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Influence of volcanic glass on the magnetic signal of different paleosols in Córdoba,Argentina

This contribution comprises geological and magnetic results obtained in loess and paleosols profiles outcropped in the Pampean plain (Argentina). The sedimentary sequence exposed in Córdoba province is represented by four profiles Corralito I, Corralito II, Monte Ral815o and Lozada, 32°S 64°14'W (Argentina). These profiles were mineralogically described and magnetically analyzed. The sediments that compound the profiles contain volcanic glass between 20 and 90%. The results of two paleosols with different percentage of volcanic glass in the parent material (correlated to Marine Isotope Stage 5, MIS 5) exposed at Corralito I and Lozada, were compared; an important relationship between environmental magnetism signal and volcanic glass content was observed. All the results suggest that there are variations between different paleosols of the same area and age; such variations are attributed to content of volcanic glass in parent material; time of exposure of the parent material to pedogenic processes; and geomorphological place of each profile. At present, it is not possible to quantify certainly the paleo-precipitation index. Only qualitative interpretation can be done taking into account many variables of the geological system.     

Combination of drainage, water supply and environmental protection as well as rational distribution of water resource in Zhengzhou mining district

It is forecasted that before the 2050s, coal would still make up 50%-60% of once energy constitution in China, but unfortunately, in most part of our coal districts and peripheral regions, we generally face the contradiction and conflict among the threat of water hazard, shortage of water resource and environmental protection, which are becoming more and more serious especially with a gradual increase in mining depth of the shaft and recovery of lower coal beds. The concrete expression is as f…     

Anomalous propagation of refracted waves beneath the Orlík water reservoir, Czech Republic

The Orlík water reservoir was built on the Vltava River in the places where the river crosses the geological unit called the Central Bohemian Pluton. Previous geological studies have disclosed no significant lateral inhomogeneity or fault zone in the close vicinity of the reservoir. However, repeated levellings, performed there in the 1950s and 1960s, revealed a systematic subsidence of the Vltava River valley. Using these measurements, the idea of the tectonic origin of the valley was even formulated. Recent seismic observations have also attracted attention to this region. Namely, a macroseismically felt earthquake occurred there on January 13, 2007, and many weaker earthquakes have been recorded by local seismic networks since 1992. To increase the accuracy of locating these seismic events, recently we have carried out refraction measurements along a short profile across the Orlík reservoir. These authors smoothed the observed travel times and derived a 1-D velocity model of the shallow crustal structure for the Orlík region. In the present paper, using the same refraction measurements, we study some anomalies in wave propagation beneath the Orlík reservoir. In particular, it is shown that the passage of seismic waves beneath the reservoir leads to their time delays and spectral changes. Moreover, we have also recognised similar time delays in earlier data from the nearby international profile CEL09 in the places where the profile crosses the Orlík reservoir.     

Influence of permeability on hydrothermal circulation in the sediment-buried oceanic crust

1 Introduction Hydrothermal circulation is the key process of hydrothermal activity. Modern seafloor hydrothermal circulation can be divided into three parts: convective cells in the oceanic curst, interface between seafloor and ocean and hydrothermal plume. Hydrothermal convection in the crust is the dominant part of the whole seafloor hydrothermal circulation. The distribu-tion and nature of hydrothermal system in the oceanic crust are controlled by crust thermal structures and permeability …     

Influence of seismicity parameter uncertainty on seismic hazard estimation of cities and towns

Introduction In his Doctor thesis, PAN (2000) has roughly studied some about the influence of parameter uncertainty on seismic hazard analysis. The aim of this paper is especially to study the uncertainty influence extent of seismic hazard analysis result in a spot, owing to the uncertainty of seismicity parameters induced by variational statistical time ranges of various statistical regions in the whole country. The authors have inquired into the uncertain extents of influence of seismic p…