نشریه پژوهش های علوم و فنون دریایی
سال دهم شماره 3 (پاییز 1394)

Some dinoflagellates produce cysts in harsh environmental condition, which sink on the surface of bottom sediments. These cysts have an important ecological role in distribution of dinoflagellates species, survival in bad condition and in genetic recombination (when they are formed in the process of sexual reproduction). To find dinoflagellate cysts in marine sediments of Hormozgan province, sampling was done in 27 stations in 2012. Samples were transported to laboratory under dark condition and then analyzed. The cyst of three orders of dinoflagellates and two genera of diatoms were identified in sediment samples. The observed dinoflagellate cysts were in the orders Peridiniales (59% or 53 cysts), Gonyaulacales (28% or 25 cysts) and Gymnodiniales (2% or 2 cysts ) respectively. The Peridiniales cyst were identified (19% or 17 cysts) at order level taxon, [37% or 33 cysts at genus level taxon (Protoperidinium 20% (or 18 cysts) and Scrippsiella 17% (or 15 cysts)] and 3% (or 3 cysts) at species level taxon (including Ensiculifera carinata, Scrippsiella irrigularis and Scrippsiella (cf. trochoidea)). The Gonyaulacales cysts were identified (22% or 20 cysts) at order level taxon, 5% or 4 cysts) were as genus Alexandrium and 1% or 1 cyst were as genus Alexandrium affine. The Gymnodiniales cysts were identified (2% or 2 cysts) at order level taxon. Moreover, 10 cysts (11%) were unknown dinoflagellates cysts which were mostly calcareous cysts. A significant numbers of diatoms cysts (belonging to genera Coscinodiscus and Surirella) were also identified in sediment samples.

In this study, adsorption of Zn2+ and Cd2+ on the synthesised (5- Amino-2-benzotriazd-2-yl-phenol) resin for preconcentration of mentioned ions, on both batch and column methods were studied. The optimum pH for adsorption of the metal ions was 6.5 and the recovery was above 80%. The effect of temperature on adsorption was investigated. The results showed that the best adsorption was at 25 ͦC and concentration of 100 mg/L. Hence with increasing concentration the adsorption of mentioned ions increased by this resin. The best adsorption was at room temperature, thereby increasing stability of resin with lowest cost. In the column method, the flow rate of the solution passing through the column for maximum adsorption of metal ions was optimized and 0.5 M nitric acid was used as the eluting solvent. The concentrations of metal ions were detected using atomic absorption spectroscopy. With batch method, Zn2+ and Cd2+ concentrations in water sample were 0.000915 mg/L and lower than sensitivity detection limit of the instrument, respectively. Thereafter, for determination of zinc and cadmium ions in Persian Gulf sea water samples, preconcentration process with 100 and 10 times concentration factor was performed, respectively.

In this study the efficiency of bioreactors containing Spirulina algae in removal of orthophosphates from municipal wastewater was investigated. Physical factors such as light, temperature, pH, agitation and aeration, and chemical factor such as culture medium can be an important factor influencing the growth of micro-algae. Spiral Helical photobioreactor and Zarrouk medium as culture medium were used for the removal of phosphorus from municipal wastewater. Microalgae stabilized in the culture medium with different amounts of air (zero and 1.3 L/ min) were added to 4.5L municipal wastewater in photobioreactor. The concentration of orthophosphates absorbed was measured by a spectrophotometer (DR/4000 HACH) at different time intervals. In an 18-day period, performance of the bioreactor containing Spirulina algae in removal of orthophosphates from municipal wastewater was studied. The results showed that without aeration, orthophosphate concentration of 38.46 mg / L reduced to 11.54 mg/L. Aeration flow of 1.3 L/min reduced orthophosphate concentration from 60gr/Lit to 20gr/L. In other words, the bioreactor containing Spirulina algae, had an efficiency of 69.9% for the removal of orthophosphates, without aeration, and an efficiency of 80%, with aeration (flow rate of 1.3 L/min) (The percentages quoted are average of three replicates).

One of the toxic pollutants in aquatic ecosystem is heavy metals. This study aims to elucidate the toxic impact of zinc on the structure of gill and liver in silver carp (Hypophthalmichthys molitrix). This study was conducted at spring 1390 at the International Sturgeon Research Institute. In this study, after adaptation, 135 fish with the length of 13±1 cm and the weight of 50±10gr were put in one control group and 2 treatment groups contained 0, 5, and 10mg/L (Zn (NO) 3)2 in 90 liter aquariums. Fish were sampled at 12, 24, 48, 72 and 96 hours. The samples of gill and liver in each treatment were immediately fixed in Bouin solution and 5μ sections were stained by Hematoxylin-Eosin general staining method. In histological study of gills, epithelial cell hyperplasia was encountered, that had increased with high metal densities. Initially lamella cells wrinkled and change of formation was observed in chloride cells. This lesion enhanced in higher densities. Fish liver exposed to zinc showed atrophy,cloudiness, swelling, hyperemia, vacuolation and necrosis. These hepatic alterations were more evident in fish exposed to high metal densities. In conclusion, the present study showed that histopathology of liver and gill in silver carp, is a useful biomarker for environmental pollution, since it discriminated between reference and test sites.

This study aimed to evaluate the effect of parsley (Petroselinum sativum)on growth factors of Rainbow trout. Therefore, from August to October 2014 6,000 Rainbow trout fish of 100 grams of weight in 3 treatments and 1 control group with 3 replications were fed. Diets consisted of 3 levels of parsley powder at 1%, 3% and 5%, respectively. In general, the highest weight was found in the last day of treatment number 3 samples with an average weight of 269 ± 24 g and the lowest on the first day of the control samples with an average weight of 146 ± 29 g The greatest increase in length was noticed in the treatment number 3 samples with an average length of 24/95 ± 2/12 cm and the least growth in length was observed in the samples from treatment number 1 with an average length of 23/4 ± 1/941 cm. One-way ANOVA test with Tukey HSD test showed strong significant difference among different treatments for weight gain and growth in length (P <0/05). Pearson correlation test showed a strong linear relationship between the increase in weight and length with the increase in the concentration of the parsley powder the whole period (P <0/05). Dried parsley (Petroselinum sativum) used in the study, showed significantly strong ability to influence growth performance and be used as feed for Rainbow trout. Therefore, we can probably say that dried parsley can be a good supplement to fish diet. Finally, it was diagnosed that parsley powder at 5.0 percent in the diet, is the optimum dosage for use in feed for trout in the long term.

Oil extracted from microalgae, is a potential energy source, as it can be easily converted to fatty acid methyl ester or hydrocarbon type biodiesel. The aim of the present work was to optimize the production of biodiesel by Chlorella vulgaris in mixotrophic and autotrophic cultivated conditions. Comparison of cell growth rate of Chlorella vulgaris was carried out, in TMRL(AG) and TX batch culture media, in four treatments and three repeats for ten days. In each treatment, Chlorella vulgaris was counted every two days once. Based on the results of this survey, the highest cell growth, 118×106 cell/ml, was recorded in autotrophic condition in TMRL(AG) medium and lowest count number was 77× 106 cells/ml in TX medium, in mixotrophic condition. There was significant difference between different media and average density of microalgae Chlorella vulgaris cell growth in ten days (p≤0.05). In this study, growth rate and growth coefficient showed more rapid growth of Chlorella in TMRL medium compared with TX medium. Oil content in TMRL (AG) media in mixotrophic and autotrophic cultivation conditions were %4.22 and %1.21, respectively. Our results revealed, for large scale culture of microalgae Chlorella, in order to be used in industrial biodiesel production, TMRL(AG) medium showed higher cell growth rate, greater amount of oil production and lower overall cost, in mixotrophic condition.

Interaction between sea and air is an important factor in controlling seasonal climatological variations in each environment. In this research, relationship between Sea Surface Temperature (SST) and wind speed over coastal area of Hormozgan province has been studied. Initially the SST data of the area were collected using AVHRR sensor of NOAA satellite and the wind speed data were collected from QuikSCAT satellite. After analyzing the satellite data for the SST and wind speed, monthly, seasonal and annual variations of these data were studied. The significance of their variations were evaluated during years 1985-2008, using a long term study group of each variable as a control and then comparison was made using Duncan test. As the increasing trend of mean annual surface temperature and the decreasing trend in wind speed was significant, correlation coefficient between SST and wind speed was obtained. After plotting the time against surface temperature during the study period, it was observed that the minimum temperature was 21.11 ˚C in 2008 and the maximum was 33.12 ˚C in 2002. It was shown that there was 4.2 ˚C temperature difference between western and eastern region of the sea coast in summer and the temperature gradient reaches 3 ˚C in winter. It can be concluded that for summer 75% and for winter 33% increase (decrease) of the mean sea surface temperature takes place and the deviation of mean wind speed will be increase (decrease).

Benthic macroinvertebrate communities are one of the key biological components considered for the assessment of benthic integrity in the context of the Water Framework Directive. The effect of industrial and agricultural wastewater effluent on water quality, habitat quality, and benthic macroinvertebrates of an urban stream in Namrood River located in Firoozkooh (Tehran province, Iran) was investigated in this study. The Namrood River is situated by the main road and is being polluted by pollutants from tourism industry and recreational centers, gas stations, sewage from villages, agricultural wastewater and fish culture effluent. In the present study, three stations were selected, one station as blank and two stations, up and downstream were selected to sample the sediments and Chironomidae and Gammarus pluex in both cold and warm seasons of the year. The copper and zinc levels were measured in sediment and benthos. The results showed that copper and zinc concentration range in benthos were 0.170-0.966 and 0.187-3.846 ppm, respectively. Sediments of the upstream station had the highest copper concentration among the samples in both cold and warm seasons of the year and the highest concentration of Zn was observed in sediments of upstream station in cold season.Comparing the average concentration of studied elements with WHO permissible limits showed concentrations lower than standard for Copper and Zinc element in sediment and benthos.‌