How to save the dying Lake Urmia

1 Introduction Lake Urmia in the northwestern corner of Iran is one of the largest permanent hypersaline lakes in the world and the largest lake in the Middle East(1,2,3).The lake was

Adaptive Extended Isogeometric Analysis for Steady-State Heat Transfer in Heterogeneous Media

Steady-state heat transfer problems in heterogeneous solid are simulated by developing an adaptive extended isogeometric analysis(XIGA)method based on locally refined non-uniforms rational B-splines(LR NURBS).In the XIGA,the LR NURBS,which have a simple local refinement algorithm and good description ability for complex geometries,are employed to represent the geometry and discretize the field variables;and some special enrichment functions are introduced into the approximation of temperature field,thus the computational mesh is independent of the material interfaces,which are described with the level setmethod.Similar to the approximation of temperature field,a temperature gradient recovery technique for heterogeneous media is proposed,and based on the Zienkiewicz–Zhu recovery technique a posteriori error estimator is defined to automatically identify the locally refined regions.The convergence and performance properties of the developed method are verified by using three numerical examples.The numerical results show that(1)The convergence speed of the adaptive local refinement is faster than that of the uniform global refinement;(2)The convergence rate of the high-order basis functions is faster than that of the low-order basis functions;and(3)The existing inclusions change the local distributions of the temperature,and the extreme values of the temperature gradients take place around the inclusion interfaces.

A regional suspended load yield estimation model for ungauged watersheds

Developing regional models using physiographic, climatic, and hydrologic variables is an approach to estimating suspended load yield(SLY)in ungauged watersheds. However, using all the variables might reduce the applicability of these models. Therefore, data reduction techniques(DRTs), e.g., principal component analysis(PCA), Gamma test(GT), and stepwise regression(SR), have been used to select the most effective variables. The artificial neural network(ANN) and multiple linear regression(MLR) are also common tools for SLY modeling. We conducted this study(1) to obtain the most effective variables influencing SLY through DRTs including PCA, GT, and SR, and then, to use them as input data for ANN and MLR; and(2) to provide the best SLY models. Accordingly, we used 14 physiographic, climatic, and hydrologic parameters from 42 watersheds in the Hyrcanian forest region(in northern Iran). The most effective variables as determined through DRTs as well as the original data sets were used as the input data for ANN and MLR in order to provide an SLY model. The results indicated that the SLY models provided by ANN performed much better than the MLR models, and the GT-ANN model was the best. The determination of coefficient,relative error, root mean square error, and bias were 99.9%, 26%, 323 t/year, and 6 t/year in the calibration period, and 70%, 43%, 456 t/year, and 407 t/year in the validation period, respectively. Overall, selecting the main factors that influence SLY and using artificial intelligence tools can be useful for water resources managers to quickly determine the behavior of SLY in ungauged watersheds.

Reduction of the wind erosion potential in dried-up lakebeds using artificial biocrusts

The artificial creation of biocrusts can be a rapid and pervasive solution to reduce wind erosion potential(WEP)in dried-up lakes(e.g.,Lake Urmia).So,in this study,we created a biocrust by the inoculation of bacteria and cyanobacteria on trays filled by soils collected from the dried-up bed of Lake Urmia,Iran,to reduce WEP in laboratory conditions.We used the wind erodible fraction of soil(EF)and soil crust factor(SCF)equations to calculate the WEP of the treated soils.EF and SCF were decreased(p<0.05)through applying the co-inoculation of bacteria and cyanobacteria by 5.6%and 10.57%,respectively,as compared to the control;also,the"cyanobacteria alone"inoculation decreased EF by 3.9%.Our results showed that the artificial biocrusts created by soil inoculation,especially with the co-using of bacteria and cyanobacteria,significantly reduced the WEP of a newly dried-up lakebed.Furthermore,we found that inoculation decreased the WEP of the study soil by increasing the soil organic matter content from 3.7 to 5 fold.According to scanning electron microscopy images,the inoculated microorganisms,especially cyanobacteria,improved soil aggregation by their exopolysaccharides and filaments;thus,they can be used with other factors to estimate the soil erodibility in well-developed biocrusts.The inoculation technique could be considered as a rapid strategy in stabilizing lakebeds against wind force.However,it should be confirmed after additional experiments using wind tunnels under natural conditions.

Redesigning crop varieties to win the race between climate change and food security

Climate change poses daunting challenges to agricultural production and food security.Rising temperatures,shifting weather patterns,and more frequent extreme events have already demonstrated their effects on local,regional,and global agricultural systems.Crop varieties that withstand climate-related stresses and are suitable for cultivation in innovative cropping systems will be crucial to maximize risk avoidance,productivity,and profitability under climate-changed environments.We surveyed 588 expert stakeholders to predict current and novel traits that may be essential for future pearl millet,sorghum,maize,groundnut,cowpea,and common bean varieties,particularly in sub-Saharan Africa.We then review the current progress and prospects for breeding three prioritized future-essential traits for each of these crops.Experts predict that most current breeding priorities will remain important,but that rates of genetic gain must increase to keep pace with climate challenges and consumer demands.Importantly,the predicted future-essential traits include innovative breeding targets that must also be prioritized;for example,(1)optimized rhizosphere microbiome,with benefits for P,N,and water use efficiency,(2)optimized performance across or in specific cropping systems,(3)lower nighttime respiration,(4)improved stover quality,and(5)increased early vigor.We further discuss cutting-edge tools and approaches to discover,validate,and incorporate novel genetic diversity from exotic germplasm into breeding populations with unprecedented precision,accuracy,and speed.We conclude that the greatest challenge to developing crop varieties to win the race between climate change and food security might be our innovativeness in defining and boldness to breed for the traits of tomorrow.

TEMPERATURE,RAINFALL VARIATIONS AND THEIR ANOMALIES OVER CHINA UNDER THE COLD-WARM BACKGROUND IN THE 20TH CENTURY

In this study,the climate trend of the annual average air temperature and total annual rainfall in China in the present century has been examined.It is noted that in the Northwest,the Northeast and North China the climate has become notably warmer this century but the rainfall trend has not been evident,mainly negative.In the 1980s China's rainfall and temperature showed noticeable regional features: warm and dry in North China,cold and dry in the Southwest,warm and wet in the Northeast,cold and wet in the middle-lower reaches of the Changjiang River.Besides,the four interdecadal climate change features and ranges of this century have been studied.It is found that on the scale of several decades there was considerably less rainfall in the most part of China in the warm background than in the cold background.The increase of temperature which started from the 1970s mainly happened in the Northwest and Northeast,while to the south of the Huanghe River the temperature increase did not even as great as in 1940s.The corresponding rainfall feature is that most areas experienced much less rainfall except the area to the south of the Huanghe River and over the Changjiang and Huaihe River basin.

Effects of type, level and time of sand and gravel mining on particle size distributions of suspended sediment

Monitoring the sediment transport behavior induced by different interventions, particularly sand mining from rivers, is needed to adaptively manage the watersheds. The particle size distribution of the sus-pended sediment in up and downstream of rivers is one of the main indicators to know about fate of sediments, which may be varied in different conditions. We investigated the effect of some types of sand and gravel (i.e., manual and low, semi-heavy, and heavy machinery) mining on particle size distribution of suspended sediment in the Vaz-e-Owlya, Vaz-e-Sofla and Alesh-Roud riverine mines located in Ma-zandaran Province, northern Iran. The study was conducted on a monthly basis from February, 2012 to January, 2013. Laser granulometry was used to analyze the particle size distribution of suspended se-diment samples taken from up and downstream sections of the study mines. The results revealed that the level and intensity of mining activity affected particle size distribution of suspended sediments. Further statistical assessments in up and downstream sections of the mines proved that sorting, D50, mean, D90, kurtosis, skewness and D10 of the suspended sediment were not significantly influenced by mining activities at levels of 0.09, 0.11, 0.12, 0.15 to 0.69, 0.15–0.69, 0.77, 0.87, 0.97, respectively. While it was not statistically significant, we found that the type of mine and the level of the exploitation changed the particle size distribution of the suspended sediment.

The effects of dietary administration with chemical treated Saccharomyces cerevisiae strain YG3-1 on the growth of aquatic invertebrates in Artemia

Objective:To investigate the biological effects ofβ-glucans in cell wall of new identified strain Saccharomyces cerevisiae strain YG3-1 on the growth of aquatic invertebrates,in Artemia as model organism.Methods:All yeasts used in the present study were isolated from Rainbow trout intestine and then cultured in yeast extract-peptone-glycerol medium.Activation of β-glucan in yeasts was performed by chemical treatment with 2-mercaptoethanol(2ME)(3.5%v/v).Then nauplii and larvae individuals of Artemia urmiana and Artemia franciscana(two different species of Artemia as test organisms)were fed with 2ME-treated yeasts during the culture.At the end of experiment,after feeding individual length(total length and growth rate)in adult individuals of Artemia was measured.Results:Following this administration,growth in both species of Artemia was improved(P<0.05).So,the results showed that Artemia urmiana adults individuals that fed with 2MEtreated yeasts had the highest growth and total length.These results were confirmed with growth measurement in adult individuals of Artemia.Conclusions:This study suggested that 2ME-treated Saccharomyces cerevisiae strain YG3-1 yeasts can be used for enhancing the growth of other aquatic invertebrates like shrimps as probiotic supplement and growth promoter.