جستجوی مقالات مرتبط با کلیدواژه « chabahar bay » در نشریات گروه « زیست شناسی »

For the earthquakes and resulting tsunamis assessment in the Makran subduction zone, various earthquake scenarios defined, and the tsunamis waves associated with them modeled numerically. Based on the latest research results using thermal modeling, the maximum earthquake magnitudes considered in scenarios are 8.7 and 9.1. In contrast to previous studies that simulated Makran tsunamis using only a large-scale model containing topographic and hydrographic data with low resolution, the current research introduced a local model with finer spatial networks alongside the global model to calculate run-up accurately. Tsunami modeling was carried out considering different scenarios, using Boussinesq and non-linear shallow water models. The results indicate a significant importance difference in using Boussinesq and non-linear shallow water models. For smaller earthquakes like 8.3, the difference is much greater than for larger earthquakes like 9.1. This difference in the 8.3 earthquake may be due to the penetration of tsunami waves into the Chabahar bay and wave breaking inside the bay, where the Boussinesq model is more capable of accurately simulating wave breaking compared to the non-linear shallow water model. Meanwhile, for the 9.1 earthquake, due to the very high waves, most waves break before entering the bay and we observe less wave breaking inside the bay compared to the 8.3 earthquake scenario.

In this study, a sensitive and economical method is suggested for the rapid determination of formaldehyde in seawater samples. This method is based on the reaction of formaldehyde with 5, 5-di methyl-1, 3-cyclohexane dion (dimedone) in the presence of ammonium acetate. After the reaction of derivative, a mixture of 900 µL of ethanol as a dispersive solvent and 100 µL of chloroform as an extraction solvent was rapidly injected into a water sample containing formaldehyde. Their concentrations were determined spectrophotometrically in micro-cuvettes at 395 nm. Under the optimum conditions, the calibration graph was linear in the range of (0.1-100) µg/L with the detection limit of 0.02 µg/L and limit of quantification of 0.07 µg/L for formaldehyde. Parameters affecting extraction efficiency including pH, type and volume of extraction and disperser solvents, and amount of dimedone, were investigated and optimized. Under the optimum conditions, the linearity of the technique was in the range of 0.1-100.0 µg. L-1 with a detection limit of 0.02 µg. L-1 for the same compound. The relative recoveries of formaldehyde from seawater samples at spiking levels of 10 µg. L-1 were between 97.0-99.4%. The proposed method was successfully applied for the determination of formaldehyde in seawater of Chabahar Bay.

Coral ecosystems, like other natural habitats, are under the influence of global warming. Every year we see the bleaching of corals in different parts of the world. Since the physical parameters of seawater are affected by meteorological phenomena, so in this study using ten-year data of oceanographic buoys, the effect of physical parameters of seawater including water surface temperature, salinity, acidity and electrical conductivity on the phenomenon of bleaching of branching corals in Chabahar Bay was investigated.

For this purpose, the trend of multi-year data of marine parameters was determined by non-parametric Mann-Kendall test. In the next step, the Pearson correlation test showed the correlation between seawater parameters and choreographed Zooxanthellae algae color score data as a coral health index produced by the authors during long-term diving operations using the Coral Watch method.

The results of this study showed that among the four parameters: water surface temperature, electrical conductivity, acidity and salinity, the highest correlation and the most effective independent variable in multivariate regression between coral health and seawater parameters is concern to EC.

Due to the insignificance of the increasing trend of water surface temperature in previous years and the existence of a significant negative correlation at the level of 0.01 between the health status of corals and water surface temperature, fortunately, the branching corals of Chabahar Bay have been in good condition. As human and sea pollutants are controlled in the coming years. We will see the survival of this valuable ecosystem.

Chabahar Bay is a semi-closed and shallow bay in southeastern of Iran and is strongly affected by the monsoon conditions. The 3D FVCOM model was used to study the hydrodynamic conditions of Chabahar Bay. For this purpose, a horizontal grid with 6290 triangular elements and a vertical grid with 10 sigma layers were created. The model was implemented in baroclinic mode; NCEP data and HYCOM model outputs were used to account for open surface and boundary layer forces. Water level and flow velocity correlations show acceptable agreement with field data. The tidal bay is often semi-daily and mixed and the tidal range is 2.7 m. The flushing time of Chabahar Bay was calculated to be 6.7 days. The modeling results show; The vertically and annual average current velocity is 0.1 m/s and the rotation pattern is often anticyclonic.

The effects of using the biorock method on the growth and survival of coral (Pocillopora damicornis( in the Chabahar Bay were evaluated. Coral pieces were placed on steel structures under a 6V electric field in the biorock process. The coral growth, growth performance and survival rates of corals during the twenty-eight weeks were studied. The mean coral growth in the biorock structure was 10.66 ± 0.3cm and the mean coral growth was 5.27 ± 0.2 cm in the non biorock structure. The results show a significant difference between coral growth in the biorock with non biorock structures (p <0.05). The results of this survey on the growth rate of Coral (P.damicornis( in the biorock structure compared to the control structures showed a two-fold increase in growth and a higher survival rate. The results of this study indicated that stimulation of coral growth by biorock method as well as the rapid responses of this species to the electrical field during the biorock process which could be used to stimulate coral growth survival for the protection and rehabitation program.

Environmental pollution imposes serious hazards and problems to the living organisms. This study aimed to determine the concentration and seasonal alteration of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DnBP) in the surface water of Chabahar Bay. Four replicated water samples were taken from the surface layers of seven stations in Chabahar Bay and prepared by dispersive liquid–liquid microextraction (DLLME) method, before being injected into the Gas Chromatography with flame ionization detector. In this method, 0.5 ml of methanol (as diffusion solvent) and 20 µl of carbon tetrachloride (as extraction solvent) were injected quickly into the sea water samples, and after extraction, the deposited phase was taken by a Hamilton syringe and injected into the GC equipment for measurement. Under the optimum extraction and experimental conditions, the method yields a linear calibration curve in the concentration range from 10 to 600 µg/L for target analytes. The enrichment factors for DEHP and DnBP were 775 and 790, the correlation factor 0.997 and 0.997, the limits of detection were 0.04 and 1.78 µg/L and the relative standard deviations of DEHP and DnBP were 0.0036 and 0.058, respectively.The results revealed that the concentration of DEHP and DnBP differ considerably at different stations. Significant differences were also observed between the concentration of DEHP and DnBP at various stations (P ≤ 0.05).

The phenolic compounds contain antioxidant properties that can be effective in the treatment of some chronic and malignant diseases. The aim of this study was to determine optimal conditions for extraction of total phenolic compounds from Sargassum sp. and Sea lettuce (Ulva sp.) in Chabahar coastal waters. The extracts of these two algae were extracted by ultrasonic method and then the different parameters consisting of solvent type (water, methanol, ethanol, or acetone), sample size (63, 125, 250, or 500 micron) and dry sample (0.1, 0.2, 0.3, 0.4, or 0.5 g) in 10 ml solvent and ultrasonic time (10, 20, or 30 mins) and temperatures (20, 40, 50, or 60°C) were optimized. The determination of total phenolic compounds were done by spectrophotometric method using Folin ciocalteu reagent and standard curve gallic acid. Maximum total phenol content was obtained by water as a solvent, particle size of 125 microns for Sargassum sp. and 250 microns for Ulva sp., dry extract of 0.1 g per 10 ml solvent for Sargassum sp. and dry extract of 0.2 g per 10 ml solvent for Ulva sp. and ultrasonic time of 10 minutes at 40 ° C for both algae. Under the optimized conditions, the highest total phenolic compounds were obtained for Sargassum algae (i.e.5.58 ± 0.271 mg gallic acid per gram of dry sample) and for Sea lettuce (i.e.2.047 ± 0.258 mg gallic acid per gram of dry sample). The results of the study showed that Sargasum algae can be used as a appropriate natural marine antioxidant source in the food and pharmaceutical industries as well.

The scope for growth as a proportion of the energy absorbed and is а measure of the efficiency with which the food is converted into body tissues. It is mentioned in both net and gross growth efficiency. In this study, the scope for growth and growth efficiency of the bivalve Azumapecten ruschenbergerii have been investigated at Chabahar Bay before and after summer monsoon, as a laboratory experiment. Monsoonal climate dominates the northern Indian Ocean, and its effects felt in summer and winter with stronger winds in summer. According to this, the study on the energy budget of mentioned bivalve at 19 to 33 °C showed that the average of both indices has significant increase after summer monsoon (P<0.001). The results indicated that A. ruschenbergerii is opposed to better condition and less stress after the monsoon.

Environmental quality assessments recommend use of sessile invertebrates. Because, they are unable to escape from environmental deterioration. In addition, the ability of adaptive responses to such environmental change, would determine its survival and reproduction potential. The organism adaptability may therefore be defined by its capacity to adjust the physiology to operate with optimal efficiency in a variable environment. Indicators that are discussed in this field for Azumapecten ruschenbergerii, at the Chabahar Bay and in the time before and after the monsoon, include: the ratio of consumed oxygen to excreted nitrogen and body condition index. The first is widely used to study the metabolism of animals. The second is the occupied space of internal volume of the shell by the body. Accordingly, stress indices were determined and statistically evaluated. The average of both indices was associated with significant changes (increase for the first and decrease for the second one) in relation to pre- and post-monsoon period (P<0.05). Evaluating both indicators suggests less environmental stress in the post-monsoon period to this bivalve living in sampling sites

Among the many biochemical biomarkers used to assess contamination of the marine environment, metallothionein protein is considered as one of the very important and useful tool inrelated to biochemical markers metals. The aim of this study was to evaluate Metallothionein changes in natural condition in polychaete Glycinde bonhourei of 9 stations Chabahar Bay sub-tidal area from 2014 to 2015 with consideration before the monsoon season, monsoon, post-monsoon and concentrations of copper, zinc ,cadmium in the polychaete tissue. Total average concentrations of copper and zinc and cadmium respectively recorded in the monsoon 6.39±2.04, 20.95±4.51, 0.136±0.04 micrograms per gram dry weight of the monsoon season 3.51±1.46, 11.84±2.65, 0.059 ± 0.01 and in the post-Monsoon 4.98 ±1.44, 16.51±3.58, 0.152±0.01 microgram per gram of dry weight that one-way analysis of variance showed significant difference between the station and seasons (p

The aim of this study was to measure the concentration of heavy metals (Hg, Cd, Cu, Pb, Ni and V) in marine sediments as well as to determine the potential harmful effects of these heavy metals using Combined Pollution Index (CPI) and Potential Ecological Risk Index (PERI) at seven stations in Chabahar Bay. From each station, 3 samples of surface sediments (0-5 cm) were collected using Van Veen Grab and samples were extracted and analyzed according to the standard methods. The concentration levels of measured heavy metals were in the order of V>Ni>Pb>Cu>Cd>Hg . Contamination assessment based on CPI shows that the sediment samples in the study area were heavily contaminated with the CPI>1 except for Pozm Station. The potential ecological risk indices of Pb, Cu, Ni, were lower than 40, which indicated slight potential ecological risk of all stations. The results showed that the ecological risk level of heavy metals in the sediments of Chabahr Bay were low to very high.

This study touches on abundance and distribution of brittle star Macrophiothrix cheneyi in the intertidal zones of Chabahar Bay in the Oman Sea, Iran, due to spatial and temporal variobility during a year from November on 2008 to September on 2009 at 5 selected stations. Sampling was randomly done bimonthly, by using 1m×1m qudrate. The result of study showed density of species in different stations and months has significant difference (P

In addition to heavy metals, environmental factors affect to induce the synthesis of metallothionein (MT) contamination biomarker in vertebrates and invertebrates. Environmental parameters that were selected of nine stations in Chabahar Bay subtidal area (2013-14)  include temperature, salinity, dissolved oxygen and turbidity and heavy metals (copper, zinc, cadmium) in monsoon and post-monsoon, pre-monsoon, that studied relation them with polychaete metallothionein concentration. Total mean of MT was recorded in pre-monsoon 28.3±5.2, monsoon 15.50±4.9, and post-monsoon 21.39±4.37 µg/ g and ANOVA test showed significant differences among stations and seasons (p≤0.05). There were no significant correlation between metal concentrations in sediments and tissue in stations and seasons, also between metals and MT. Except for temperature and salinity were increased in monsoon, MT and other parameters showed a significant decrease in this season. In PCA test, three components of variance revealed a total of 75.24 variance percent that the second component with 28.73 variance percent was included oxygen and transparency and MT. Despite significant changes of MT and environmental factors in different seasons and also had not been recorded correlation of MT induction with metals, as the main factors in the induction, emphasis the role of Chabahar Bay environmental parameters on biomarker fluctuations. Among the factors under the PCA, dissolved oxygen of the main factors is effective in reducing the synthesis of MT in G.bonhourei.

Chabahar Bay near Makran Sea, with the ports of transactions, has always been under the influence of annual monsoon the Indian Ocean. Density changes and heavy metals copper and zinc of Chabahar bay subtidal sediments were studied in 22 stations and three seasons that include: pre-monsoon, monsoon and post-monsoon during 2014. Polychaeta abundances mean were for premonsoon 1261.49±38.81, monsoon 513.81±65.6, postmonsoon 630.45± 73.84 ind/m2 that significant difference was observed between stations and seasons (p<0.05). Metals copper and zinc had fluctuations in three seasons, but despite the significant differences between the stations, there was no significant difference between seasons. Metals mean in preM, M, postM respectively for Cu include 19.89±3.34,14.42±4.47,12.9±3.4 and for Zn 73.42±5.51, 66.04±6.37, 61.72±4.86 µg/g dry weight that only in three stations and only in Cu, concentrations were higher than ERL but in total Chabahar bay metal mean were lower than ERL. Significance correlations were not observed between Polychaeta density and heavy metals except for copper in pre-monsoon. The results showed the impact of monsoon currents in the distribution pattern of polychaete and heavy metals and also were no significant differences in the relationship between density and concentration of can be as results of the low concentration heavy metals in sediments of international standards and other environmental factors on polychaeta density.

In the present study, energy budget of dominant bivalve of the Oman Sea, Azumapecten ruschenbergerii, was evaluated at Chabahar Bay subjected to changes of temperature and food, before and after monsoon. Scope for growth (SFG) is used to indicate ecophysiological condition of animals. It is determined in studying energy budget. SFG values were calculated for seawater temperature, lower and higher temperatures, and also when pecten fed with different microalgae. Furthermore, enthalpy of its adductor muscle was calculated and subjected to statistical analysis. Averages of SFG values were negative before and positive after monsoon. SFG values were generally higher when fed with Microalgae Dunaliella sp. Moreover, despite of significant difference between SFG values before and after monsoon, enthalpies of adductor muscles (edible part) have not shown significant difference. So, this study suggests that 1) The above mentioned Microalgae has more feeding efficiency, 2) This mollusk had more excreting than absorbed energy and 3) It can be one of the best animals in aquaculture purposes and an effective factor to reduce blooming in aquatic areas.

This study has been carried out in the coast of Chabahar Bay from March, 2013 to Febuary, 2014. We sampled macrofouling organisms in three stations. Overall, 40 species of macrofouling organisms were detected in which Barnacles, sponges, Bryozoans, echinoderms, Polychaetes and Gastropods were the major groups. The majority of biomass and highest density were observed in the first half of the sequence. Biomass and density differences in the sequence of 6 months on structures was evident. Amphibalanus amphitrite had the highest participation in these sequences.

The aim of this paper was to study monsoon effects on polychaetes population structure in subtidal area based on some biodiversity indices. Sediments sampling was carried out by grab van-veen from 12 subtidal stations in three time periods (pre-monsoon, monsoon and post-monsoon). The physical and chemical parameters were also recorded. Mean density of polychaetes were recorded 1101.2 ±614.3 ind/m2 (pre-monsoon), 428.9 ±316.2 ind/m2 (monsoon) and 588.8 ±313.3 ind/m2 (post-monsoon). Shanon diversity indices were 2.08, 1.63, 1.83 respectively. The Hill indices was reversed and showed highest number in monsoon season and minimum number in pre-monsoon. These results represented non-uniform polycheates distribution during pre-monsoon. Cluster analysis of each season showed that deep stations were in separate disturbances. During the summer monsoon, variations in environmental factors and bottom distractions affected the density and diversity of polychaetes and as a stressor reduced the diversity and density during the monsoon.

The population dynamics depend on their environment and habitat stability and environmental conditions are the main element effecting biodiversity and richness. The main objective of this study is assessment of biodiversity of intertidal crabs in chabahar bay. During this research TOM, Moisture, Density, Dominance, Richness and Evenness have measured. For this purpose, Sampling were carried out at 3 stations, Tiss, Jazireh Kharchang and Konarak, in one period in July 2009. Totally, 7 species recorded, belonged to the family Ocypodidae. The results of biodiversity indice's in 3 Stations have been shown which Jazireh Kharchang with 5 species and Konarak with 1 species have the highest and lowest diversity, respectively. Whereas, The Percentage of TOM and Grain Size showed significant differences between the 3 Stations, while the highest TOM and lowest sand Percentages observed in Jazireh Kharchang.