Influence of two different dietary zinc sources in freshwater prawn Macrobrachium rosenbergii post larvae

Journal of Oceanology and Limnology - A feeding experiment was conducted to evaluate the effects of bulk zinc (B-Zn) and zinc nanoparticles (Zn-NPs) on survival, growth, compositions of amino acid...     

Rainfall intensity characteristics at coastal and high altitude stations in Kerala

Rainfall intensities measured at a few stations in Kerala during 2001–2005 using a disdrometer were found to be in reasonable agreement with the total rainfall measured using a manual rain gauge. The temporal distributions of rainfall intensity at different places and during different months show that rainfall is of low intensity (< 10 mm/hr), 65% to 90% of the time. This could be an indication of the relative prevalence of stratiform and cumuliform clouds. Rainfall was of intensity < 5 mm/hr for more than 95% of the time in Kochi in July 2002, which was a month seriously deficient in rainfall, indicating that the deficiency was probably due to the relative absence of cumuliform clouds. Cumulative distribution graphs are also plotted and fitted with the Weibull distribution. The fit parameters do not appear to have any consistent pattern. The higher intensities also contributed significantly to total rainfall most of the time, except in Munnar (a hill station). In this analysis also, the rainfall in Kochi in July 2002 was found to have less presence of high intensities. This supports the hypothesis that the rainfall deficiency was probably caused by the absence of conditions that favoured the formation of cumuliform clouds.     

A Multiscale Assessment of Shallow Groundwater Salinization in Michigan

Managing nonpoint-source (NPS) pollution of groundwater systems is a significant challenge because of the heterogeneous nature of the subsurface, high costs of data collection, and the multitude of scales involved. In this study, we assessed a particularly complex NPS groundwater pollution problem in Michigan, namely, the salinization of shallow aquifer systems due to natural upwelling of deep brines. We applied a system-based approach to characterize, across multiple scales, the integrated groundwater quantity–quality dynamics associated with the brine upwelling process, assimilating a variety of modeling tools and data—including statewide water well datasets scarcely used for larger scientific analysis. Specifically, we combined (1) data-driven modeling of massive amounts of groundwater/geologic information across multiple spatial scales with (2) detailed analysis of groundwater salinity dynamics and process-based flow modeling at local scales. Statewide “hotspots” were delineated and county-level severity rankings were developed based on dissolved chloride (Cl⁻) concentration percentiles. Within local hotspots, the relative impact of upwelling was determined to be controlled by: (1) streams—which act as “natural pumps” that bring deeper (more mineralized) groundwater to the surface; (2) the occurrence of nearly impervious geologic material at the surface—which restricts fresh water dilution of deeper, saline groundwater; and (3) the space–time evolution of water well withdrawals—which induces slow migration of saline groundwater from its natural course. This multiscale, data-intensive approach significantly improved our understanding of the brine upwelling processes in Michigan, and has applicability elsewhere given the growing availability of statewide water well databases.     

Controlling NOx Emission of Crude Rice Bran Oil Blend for Sustainable Environment

The main objective of this work is to investigate the factors influencing the NOx control of a stationary diesel engine fuelled with crude rice bran oil blend with lesser effect on smoke density and brake thermal efficiency (BTE). Fuel injection timing, percentage of EGR, and fuel injection pressure are chosen as the factors for the objective and NOx emission, smoke density, and BTE are considered as the response variables. To critically analyze the effects of the chosen factors on the objective three levels were chosen in each factor and the experiments were designed by following the design of experiments method. Taguchi's L₉ orthogonal array was used to conduct the tests with different combination of factor levels. Through analysis of variance (ANOVA) method, the most influencing factors and also the significance of each factor affecting each response variable were found out. Response graph was drawn for each response variable to determine the optimum combination of factor levels in achieving the objective and the obtained combination was confirmed experimentally.     

Spatial distribution of atmospheric carbon monoxide over Bay of Bengal and Arabian Sea: Measurements during pre-monsoon period of 2006

Indian Space Research Organization (ISRO) conducted the ‘Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB)’ for a two-month pre-monsoon period in 2006 with the ocean segment covering Bay of Bengal and Arabian Sea. During this campaign, carbon monoxide (CO) was continuously monitored using a non-dispersive IR analyser. Quantifying CO in ambient air is vital in determining the air quality of a region. Being toxic, CO is a criteria pollutant, but it is a weak green house gas. Globally, very few measurements exist over marine atmospheres to study its temporal pattern; particularly in situ CO measurements are few over the Bay of Bengal and Arabian Sea for comparison. Present measurements indicate: (i) predominant single peak in the diurnal pattern of CO over the marine atmosphere in contrast to the double peak over the continent, (ii) the mean diurnal CO over the marine atmosphere showing an increasing trend towards evening hours, (iii) the amplitude of the AN peaks over the marine atmosphere was ∼ 100 ppbv, while at a remote island site in the Indian Ocean it was ∼ 5 ppbv and (iv) high CO values were observed close to continent and the long range transport by wind also caused CO highs.     

Understanding fen hydrology across multiple scales

Fens, which are among the most biodiverse of wetland types in the USA, typically occur in glacial landscapes characterized by geo‐morphologic variability at multiple spatial scales. As a result, the hydrologic systems that sustain fens are complex and not well understood. Traditional approaches for characterizing such systems use simplifying assumptions that cannot adequately capture the impact of variability in geology and topography. In this study, a hierarchical, multi‐scale groundwater modelling approach coupled with a geologic model is used to understand the hydrology of a fen in Michigan. This approach uses high‐resolution data to simulate the multi‐scale topographic and hydrologic framework and lithologic data from more than 8500 boreholes in a statewide water well database to capture the complex geology. A hierarchy of dynamically linked models is developed that simulates groundwater flow at all scales of interest and to delineate the areas that contribute groundwater to the fen. The results show the fen receiving groundwater from multiple sources: an adjacent wetland, local recharge, a nearby lake and a regional groundwater mound. Water from the regional mound flows to an intermediate source before reaching the fen, forming a ‘cascading’ connection, while other sources provide water through ‘direct’ connections. The regional mound is also the source of water to other fens, streams and lakes in this area, thus creating a large, interconnected hydrologic system that sustains the entire ecosystem. In order to sustainably manage such systems, conservation efforts must include both site‐based protection and management, as well as regional protection and management of groundwater source areas. Copyright © 2016 John Wiley & Sons, Ltd.     

A study on the hydro-geologic factors that affect streamflow depletion

ABSTRACT

Evaluation of streamflow depletion induced by groundwater pumping is important for watershed management. Many analytical and numerical solutions exist for estimating depletion for various hydro-geologic scenarios. Numerical models are time consuming and require significant data input, and moreover, are problem-specific. Analytical models are convenient because of their ease of use, minimum data requirements, and instantaneous solutions, but are only applicable for idealistic scenarios. In many cases, analytical models are used for decision making on water-withdrawal permits, because they are assumed to offer conservative estimates of depletion. However, a systematic study of the applicability of these analytical models has not been done. In this research, we critically evaluate the performance of the analytical models in complex hydro-geologic settings, and list the factors that most significantly impact depletions. On the basis of this study, we find that the analytical models perform satisfactorily as a screening-level tool, though there are some situations when they perform poorly. The factors that most significantly impact streamflow depletion are spatial variability in hydraulic conductivity and the presence of other sources of water, such as lakes and wetlands. The analytical models do make conservative predictions of streamflow depletion especially for the most vulnerable streams.

Editor D. Koutsoyiannis; Associate editor X. Chen     

Assessment of surface water potential and groundwater recharge in ungauged watersheds: a case study in Tamil Nadu,India

Many of the states in India have been facing water scarcity for more than 2 decades due to increased demand, because of the increase in population and higher living standards. Consequently, many states have almost fully utilized the available surface water resources and are exploiting groundwater to augment water supplies. Investigations were carried out in the upper Thurinjalar watershed of Ponnaiyar basin in Tamil Nadu to determine the availability of surface water and to investigate the potential for enhancing groundwater recharge to support the water demand in the watershed. Increasing the water availability would also enable the community to convert the 46% of the land area in the watershed that is currently underutilised into productive uses. The surface water potential for the upper Thurinjalar watershed was assessed by applying the USDA–NRCS model with daily time steps. This modelling exercise indicated that the annual runoff from the 323 km² area of the watershed is 61 million m³. Groundwater recharge in the watershed was assessed by carrying out daily water balance method and indicated that about 43 million m³ of water from recharge is available on an annual basis or about 14% of annual rainfall. A simple regression model was developed to compute groundwater recharge from rainfall based on water balance computations and this was statistically verified. The modelling indicated that there is sufficient water available in the watershed to support current land uses and to increase the productivity of underutilised land in the area. The study also demonstrates that simple regression models can be used as an effective tool to compute groundwater recharge for ungauged basins with proper calibration.     

Morphological evolution of the Guadiana estuary and intertidal zone in response to projected sea‐level rise and sediment supply scenarios

Analysis of Holocene sediment accumulation in the Guadiana estuary (southern Portugal) during sea‐level rise since ca. 13 cal. ka BP was used to simulate the long‐term morphological evolution of the lower Guadiana estuary and the associated intertidal zone for 21st‐century predicted sea‐level rises. Three sea‐level rise scenarios given by the IPCC ( 2007 ) were used in the simulations of morphology using a large‐scale behaviour‐oriented modelling approach. Sedimentation rate scenarios were derived both from the Holocene evolution of the estuary and from a semi‐empirical estimation of present‐day sediment aggradation. Our results show that the net lateral expansion of the intertidal zone area would be about 3–5% of the present intertidal zone area for each 10 cm rise in sea level. Under constraints imposed by the lack of fluvial sediment supply, the lateral expansion of the landward boundary of the intertidal zone will occur mainly in the Portuguese margin of the Guadiana estuary, while submergence of the salt marshes will occur in the Spanish margin. Therefore the Spanish margin is highly vulnerable to both sea‐level rise and lack of sediment supply. Copyright © 2011 John Wiley & Sons, Ltd.