فهرست مطالب

  • Volume:10 Issue:2, 2013
  • تاریخ انتشار: 1391/11/11
  • تعداد عناوین: 13
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  • Khoshbavar, Rostami, H.A Page 135
    Concentration levels of 16 polycyclic aromatic hydrocarbons (PAHs) consisting of naphthalene, acenaphthylene, acenaphthene, fluorine, phenantherene, anthracene, fluor?anthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)p?yrene, dibenzo(a,h)ant?hracene, indeno(1,2,3-cd) pyrene and benzo(g,h,i)perylene were measured in water and sediment samples collected from the southern Caspian Sea coasts at four stations of Noshahr, Freydoonkenar, Sari and Amirabad during autumn, winter and spring of 2005-2006. Also, tissue samples from five sturgeon species including stellate sturgeon, Persian sturgeon, beluga, Russian sturgeon and ship sturgeon were obtained. Samples were analyzed by gas chromatography after the extraction process and the obtained data were statistically analyzed using one-way ANNOVA analysis at confidence level 95%. The mean concentrations of PAHs in water and sediment samples were in the range of 0.004-2.946 mgl-1 and 0.024-2.336? g g-1, respectively. No significant difference was seen in the mean concentrations of PAHs among stations and seasons of the examined samples. Also, mean concentration of PAHs in the liver, muscle, gill, kidney and gonad five of sturgeon species was 0.81-1.34? gg-1. The results of this study show that the levels of PAHs in water, sediment and sturgeon organs were below the acceptable levels of PAHs for the south Caspian Sea coastal regions.
  • Mohammadi, M Page 145
    This study is an attempt to evaluate the biomonitoring capabilities of rock oyster, Saccostrea cucullata, for mercury (Hg) pollution. The oyster and sediment samples were collected from 10 rocky habitats of Qeshm and Hormoz Islands in the Persian Gulf. The concentration of mercury in the shell and soft tissues of the oysters and sediments were analyzed using an advanced mercury analyzer. Biota-sediment accumulation factor (BSAF) was calculated based on the ratio of Hg concentrations in soft tissues to that in sediments. The results showed that the rate of mercury accumulation in the soft tissues of the oyster was significantly higher than that in its shell (P < 0.05). There was a significant correlation between mercury concentrations in the soft tissues and the sediments (r =0.75) According to BSAF, soft tissues of the oyster were recognized as an appropriate indicator for biomonitoring mercury. The present study generally supports the usability of soft tissue of S. cucullata as a sensitive biomonitoring organ to warn us of mercury pollution in the Persian Gulf.
  • Rowshantabari, M Page 157
    The effect of temperature on the main feeding parameters of Mnemiopsis leidyi from the southern Caspian Sea was studied in 2002. The clearance rates and daily rations were estimated from laboratory experiments in a wide range of temperatures from 12 to 27? C for M. leidyi of 12?17 mm in length. Clearance rate values changed from 52.5 to 107.3 ml ind-1 h-1. The coefficient Q10 in temperature 12 - 20? C was higher than that in 20 - 27? C (3.81 and 1.91, respectively). The specific daily ration changed from 1.56?0.19 to 0.24?0.05 mg C mg C-1 day-1 when temperature decreased from 27? C to 12? C. The direct relationship occurred between daily ration and temperature (R2=0.99). The digestion time decreased with temperature rise and did not display any clear relation to quantity of digested food.
  • Lohmander, P Page 169
    In large regions of the world, biomass is a very important source of energy. The global bioenergy market based on forest biomass is growing rapidly. About 92 % of the bioenergy in Sweden comes from forests. Biomass from forests is not homogenous. The locations, transport distances, and transport methods, can differ very much and the industries that need biomass as input prefer raw materials with different properties. In general, the economically optimal forest biomass and pretreatment methods have to be determined with consideration of the relevant objective function, constraints and information structure. The aim of this paper is to investigate typical cases and to derive general rules for optimal combinations of forest biomass and pretreatment methods in alternative situations. Mathematical models are defined, representing different versions of the forest biomass logistics, upgrading and pretreatment optimization problems. General rules of optimal decisions, based on these models, are derived and suggestions for future research and applications are given.
  • Sharifinia, M Page 181
    The distribution of macroinvertebrate communities from 5 sampling sites of the Tajan River were used to examine the relationship among physiochemical parameters with macroinvertebrate communities and also to assess ecological classification system as a tool for the management and conservation purposes. The amount of variation explained in macroinvertebrate taxa composition is within values reported in similar studies. Results of CCA ordination showed that the dissolved oxygen, water temperature, turbidity, pH and TSS were the most important physico- chemical factors to influence distribution of macroinvertebrate communities. The study revealed that macroinvertebrate communities of the Tajan River may be explained by physiochemical parameters. Mean values of Shannon?Wiener diversity index calculated for macroinvertebrates ranged from 1.35? 0.07 (S5) to 1.86? 0.10 (S1). According to the Shannon?Wiener diversity index the S1 sampling site was categorized in? ?good?? and the sampling sites S2 and S3 in? ?moderate?? and S5 in? ?moderate to substantially polluted? classes. The anthropogenic disturbances (e.g. trout farms and effluents from factories) impacted abundance and diversity of macroinvertebrate.
  • Hassanzadeh Saberm., Pourkazemi, M Page 195
    Triploidy in grass carp, Ctenopharyngodon idella Valenciennes, 1844, was induced on fertilized eggs to compare cold and heat shocks. Two simplified methods explained for verification of triploidy in grass carp. The cold shock (7? C) was given in three treatments for 30 min starting 2.0, 2.5 and 4.0 min after fertilization. In cold shock, the start point (2.0 min after fertilization) showed the highest rate of triploidy (60.9%). Heat shocks were given at 38? C, 40? C and 42? C, at 4.0 min after fertilization and lasted for 1.0 min. Produced larvae using heat shock 38? C showed 10.8% triploidy, but no signs of triploidy were seen in other heat shock treatments. Verification of triploidy in grass carp was carried out using karyotyping and measurment of erythrocytes surface area and volume in fingerlings. Ratio of erythrocytes dimention and the size of their nuclei in triploids to diploids was 2.35 and 1.80, respectively. Comparison of results obtained from the application of cold and heat shocks indicated that cold shocks are more effective than heat shocks in the induction of triploidy in grass carp.
  • Abedi, Z Page 205
    Some biological characteristics of broodstock and juvenile kutum, Rutilus kutum. were investigated using data collected from the estuaries of Tajen and Shirood Rivers (TR and SR) (southern Caspian Sea basin) as well as from the Caspian Sea in 2012. The results showed higher condition factors (CF) in the male broodstocks kutum than those estimated in the female broodstock of both TR and SR. The female juveniles displayed a greater level of CF. The Von Bertalanffy\'s growth equations were calculated as: Lt = 40.67(1? e?2.27(t?18.84)) and Lt = 50.11(1? e?0.48(t+1.814)) for the broodstocks of SR and TR, respectively, and for the juveniles as: [Lt = 48.36 (1? e?0.537 (t+ 0.913]. The males of SR presented a negative allometric growth pattern. The females and males of both SR and TR presented similar isometric growth patterns. Both male and female juveniles from TR exhibited a positive allometric growth pattern. The calculated equations for total length and weight were as: W = 3E?06 L3.2069 and W = 5E?07 L3.4745 for the male broodstock of SR and TR, respectively, and as: W = 5E?07 L3.4745 for the juveniles. The measured parameters may reflect the role of fish habitat characteristics such as food availability, population density, and age classes depending on sex and season.
  • Pourkazemi, M Page 215
    In the present study, mitochondrial DNA polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to assess the population structure and genetic relationships among six Persian sturgeon, Acipenser persicus populations from south Caspian Sea along the Iranian coast. The complete nucleotide dehydrogenase subunit 5 (NADH 5) region of mtDNA amplified by PCR was digested with five restriction enzymes. In total, 154 individuals from six populations including: Guilan (Zone1-2), Mazandaran (Zone 3 and 5), Golestan (Zone 4) and Sefidroud River, from south Caspian Sea along the Iranian coast were analyzed using five restriction endonucleases (Rsa? , Hinf? , HaeIII, Mbo? and Cfr13?), yielding 17 haplotypes. Samples from Sefidroud River were clearly identified by cluster and molecular variance model (AMOVA) analyses. This collection showed dominant haplotypes that were little in populations from the other geographic areas. The mean haplotype diversity (h) and nucleotide diversity (?) were 0.739?0.038 and 0.0105?0.0043, respectively. Based on heterogeneity test haplotype frequencies of Persian sturgeon populations and Monte-Carlo with 1000 replicates in PCR-RFLP method significant differences were seen (?2 =37.12, P< 0.0001) and these results showed that haplotype distribution in different location were significant and populations of Sefidroud were statistically significant (P< 0.0001). This result suggests that the unique genetic structure of Sefidroud River represents a highly valuable genetic resource and should now be treated as demographically independent and managed separately.
  • Devistih., Motamed, M. K Page 227
    A comprehensive assessment of drought environmental and socio-economic impacts provides critical information to rational decisions supporting drought mitigation policies and programs. The objectives of this study were to survey environmental and socio-economic impacts of drought in Guilan Province, and prioritize them from the viewpoint of paddy farmers. This study was a descriptive-correlation study, and a questionnaire was the main tool used. The validity of the questionnaire was determined by a panel of experts. The reliability of the questionnaires using Cronbach\'s alpha coefficient was 85%. The statistical population was the farmers whose basic profession was production of rice and who faced drought according to the information of Agricultural Organization (Jihad-e-Keshavarzi) in 2009. By using the proportional stratified sample method, 270 of these individuals were chosen to complete the questionnaires. The results indicated that drought, in addition to reducing the white-rice production to 312 kg per hectare, also caused some environmental and socio-economic impacts from the viewpoint of paddy farmers. Prioritizing impacts of drought were economic, environmental and social respectively. Other findings indicated that there were no statistically significant relationships between age and environmental and social impacts and between land ownership type and economic and social impacts. But, there was a statistically significant relationship between age and literacy level and economic impacts, literacy level and social and environmental impacts and between land ownership types and environmental impacts of drought.
  • Zarkami, R Page 237
    Support vector machine (SVM) was used to analyze the occurrence of roach in Flemish stream basins (Belgium). Several habitat and physico?chemical variables were used as inputs for the model development. The biotic variable merely consisted of abundance data which was used for predicting presence/absence of roach. Genetic algorithm (GA) was combined with SVM in order to select the most important predictors for assessing the presence/absence of roach in the sampling sites. Before and after variable selection, the SVM were evaluated and compared by two predictive performances namely the percentage of Correctly Classified Instances (CCI %) and Cohen\'s kappa statistics (k). The obtained results showed that before variable selection, the SVM yielded a reliable performance but the prediction further improved after the combination of SVM with GA. According to the attribute weights, the habitat variables were more responsible than physico?chemical ones in assessing the presence/absence of fish in the streams. GA also presented that roach are more dependent on the habitat variables rather than on water quality ones. Though after variable selection the predictive performances increased, the attribute weights of SVM could be an alternative substitute for GA since all input variables can be evaluated in terms of their weights.
  • Rahmanian, M Page 247
    The aim of this study was to assess the effects of heavy metal tolerant soil microbes inoculation on growth and metal uptake of pearl millet (Pennisetum glaucum), couch grass (Triticum repens) and alfalfa (Medicago sativa) in a soil spiked (and subsequently aged) with increasing concentrations of Pb. A soil sample (soil 1) was spiked with increasing (0 to 1500 mg/kg) concentrations of Pb and incubated for a seven months period. Another soil sample with a historical background of metal contamination (soil 2), having heavy metals-resistant microbial communities, also was taken and used as inocula. The plants were grown in pots containing contaminated soils. At the end of growth period, plants shoots were harvested, washed, oven-dried, ground and analyzed for Pb. The results showed a significant reduction (p < 0.05) in plants yield by increasing soil Pb concentration and inoculation of stress-adapted microbes further increased this reduction. This could be attributed to the increased access of plants to the relatively immobile Pb existed in the studied calcareous soil as well as to more metal contaminant absorption caused by soil microbial activity. In general, introduction of the microbes also resulted in lower Pb uptake by the studied plants
  • Yasouri, M Page 257
    Converting rangelands to arable land such as dry farming is widely practiced in many places in Iran. This activity could possibly contribute to the increase in downstream sedimentation. The effects of this activity on downstream watersheds are not well documented for many strategic areas in the country. One such area which is proposed for this study is the Kardeh drainage basin, located in the north east of Iran, having a catchment area of 570.9 km2. In this study, an attempt was made to quantify the changes in land use, and the sediment yield of the basin, and to identify significant contributing factors that could possibly contribute to the increased downstream sedimentation between the years of 1970 and 2007. Available satellite images and aerial photos were analyzed for the extent of land use changes and an empirical model, Erosion Potential Method (EPM) was validated and applied to quantify the annual total sediment yield of the basin. Step-wise multiple regressions were used to justify that the changes in sediment yield is due to the increased dry farming activities. The results showed a drastic change in land use between these periods where dry farming area has remarkably increased to 91%, while there was a reduction in rangeland area of about 13%. The effect of increased dry farming activities is reflected on the two fold increase in annual total sediment yield of the basin. Statistically, about 95% of the changes in sediment yield is due to the effect of increased dry land farming area in the basin (R2= 0.95,? < 0.05).
  • Ebrahimi, E Page 273
    The effects of initial spacing layout on some allometric characteristics of 12-year-old Quercus castaneifolia trees grown in Central Mazandaran, north of Iran were examined. Trees were planted in 5 different layouts (1?1, 1.5?1.5, 2?2.5, 2?3 and 4?4 m). Tree height, diameter at breast height, natural pruning height and the survival of trees were recorded in each sample plot. Tree basal area and H/D ratio and standing volume were calculated for all trees. The results of statistical analysis showed that increasing in spacing level from 1?1 to 4?4 significantly increased the average diameter at breast height from 6.93 to 12.42 cm and survival from 53% to 85%. The average tree basal area per ha decreased from 19.98 m2ha-1 to 6.43 m2ha-1 and H/D ratio from 151 to 77 when the distance between trees increased from 1? 1 to 4? 4 m. but spacing regime had no significant effect on tree height and natural pruning height. It can be concluded that on the basis of standing volume, H/D ratio and survival rate, the best plantation spacing in this research station was 2 m? 3 m. Statistically, about 95% of the changes in sediment yield was due to the effect of increased dry land farming area in the basin (R2= 0.95,? < 0.05).