نشریه پژوهش های علوم و فنون دریایی
سال هشتم شماره 4 (زمستان 1392)

In this study, a new chelating sorbent is synthesized for preconcentration and determination of Zn (II) in natural water samples (Sevin river). At first Activated Carbon is modified by Iminodiacetic acid. Cyanoric chloride is used as intermediate between Activated Carbon and Iminodiacetic acid. Then the effect of pH, interfering ions, contact time of sorbent are investigated. The results show the optimum pH, recovery and capacity of sorbent are 6.5, 98.9% and 66.6 mg/g respectively. The concentration of Zn (II) is determined by Flame Atomic Absorption Spectroscopy. Finally, it was shown that this sorbent can be used for adsorption of Zn (II) with high capacity.

To determine the heavy metals Zinc, Lead, Chromium and Copper in soft tissues of Thais mutabilis (gastropod) in three transect of tidal coast of Bandar Abbas, sampling was done in winter of 1389 (2011). Each Transect had three stations; Upper, mid and lower tidal zone. Sampling was done randomly with 0.5 square meter quadrate. Each area was sampled 9 times. The samples were analyzed for determination of heavy metals (Zn, Pb, Cr, Cu). The results showed that in the gastropod, zinc (577/18 ±438.9 ppm) was at the highest concentration between the heavy metals and Lead (0/17±0/6 ppm) was at the lowest. Generally, the highest concentration of Zinc (9/438±18/577), Lead (8/0±67/0) and Chromium (8/0±23/1) in soft tissues of gastropod was in Golshahr jonobi station, and the highest concentration of copper (6/134±77/88) was in the Posht shahr station. Statistical analysis showed that there was a significant difference (P≤0/05) in the concentration of chromium metal in soft tissue of gastropod in Golshahr jonobi transect with Soro. However, there is no significant difference between the concentrations of lead, copper and zinc in samples of soft tissue of gastropod in each transect (P≥0/05). The concentration of lead and chromium in this aquatic environment is lower than admissible range (WHO, 1985). It shows that the input of pollution containing these metals to this environment is low. The concentration of heavy metals such as zinc and copper is higher than admissible range (WHO, 1985) in every 3 transect. The result of bioaccumulation of heavy metals (Zink, Lead, Copper, and Chromium) in soft tissues of Thais mutabilis (Gastropoda) exhibited the following order: Zn> Cu> Cr >Pb.

In this study removal of Chromium VI from aqueous solution by marine brown algae Padina borgesenni as adsorant is concerned in different batch experiments. The samples were collected by a scuba diver from Hengam Island in Persian Gulf with longitude of 26̊ and 40̋ North and latitude of 52̊ and 30̋ East in 89 Fall and transferred to the laboratory. Parameters such as the initial Chromium concentration of the solution which were 125, 250, 500, 750, 1000 ppm, respectively, and the initial pH 2, 4, 7 in 6 hours were investigated. Determination of Chromium VI was conducted by atomic absorption, VARIAN AA 240, and the statistical analysis were performed by SPSS14. Elimination of Chromium VI depended on two prominent factors, the former was the initial Chromium VI concentration and the latter was the initial pH. The maximum uptake by dried biomass of Padina borgesenni was in pH 2 and 750 ppm. This study demonstrated that the initial pH played important role in Chromium uptake by the sorbent.

In this one year study, the growth parameters of Indian carp, broodstock Catla catla such as: the percentage weight gain (WG), Average Daily Growth (ADG), Specific Growth Rate (SGR), condition factor (K), length and weight of biometrics and also, some environmental parameters during the 1389 to 1390 were measured seasonally. For this, 16 brood stock Catla fish, with a sex ratio of (1:1) which was almost equal, from three ponds of 1700 m2, in which they were released, were used. Ponds before stocking, were enriched by manure. Also during the period, were enriched with chemical fertilizer. Broodstock were also provided with concentrate diet (Byza fars Company) every morning and evening. The relationship between length and weight were obtained, for the females b=3/21 and for males b =2/93. This indicates that such growth is isometric. In this relationship, the female and male respectively, equivalent to y = 0.007x3.2165 and y = 0.0197x2.9377. Growth parameters for the total period was as follows: (WG) {females: 114/27, male: 211/61}; (ADG) {females: 3/08 male: 3/68}, (SGR) {females: 0/09, male: 0/2} and Obesity factor in the broodstock was between 1/54 and 1/76 respectively. On the whole, according to prevailing environmental conditions and fish physiology, growth indicator species is acceptable. Physico-chemical factors also revealed a normal process. The results obtained showed that the adaptability of carp Catla, with the climate condition of the province (long periods of heat) is possible.

In recent years, flood producing thunderstorms have caused flood with severe human and financial damage in northwestern Iran, especially eastern Azarbaijan. In this research, we tried to obtain new and more accurate methods for acquiring knowledge about thunderstorms types. According to the weather reports, the data set containing five flood cases with twenty precipitable cells have been extracted in the area covered by Tabriz radar. Radar maximum reflectivity and its vertical cut products are used for detecting type, duration and intensity of thunderstorms. In addition, by using upper air data from sounding and General Forecast System (GFS) data with resolution of 0.5° × 0.5°, some instability indices such as K index, Showalter index, Total-Total index, Convective Available Potential Energy (CAPE), Bulk Richardson Number (BRN), Helicity, Energy – Helicity index, Vertical wind shear and precipitable water have been investigated. Results showed that the most flood producing thunderstorms were Single cell or Multi cells which after their movement and merging together, formed complex cells.

Study of phytoplankton structure and silver carp (Hypophthalmichthys molitrix) feeding was conducted in three ponds in Esfandan, Mohammadabad and Arabmahaleh (Central of Mazandaran province) to identify different species of phytoplankton in water, using 2 liter Rotner bottle of mixed sample (surface, middle and bottom) from each station of Esfandan (4m), Mohammadabad (3 m) and Arabmahaleh (4 m) every 2 weeks. Fish gut contents were also investigated during the months of June, July and August in 2012. Phytoplankton samples were fixed with 4% formalin and transported to Caspian Sea Ecology Center Laboratory (Sari). A total of 50 phytoplankton species were determined from these 3 fish ponds, which belonged to Cyanobacteria (11 species), Chlorophyta (18 species), Bacillariophyta (19 species) and Euglenophyta (2 species). Laboratory analysis results indicated that phytoplankton species composition in Esfandan, Mohammadabad and Arabmahaleh were 44, 47 and 41 species, respectively. Most of the phytoplankton present in Esfandan belonged to Bacillariophyta (39%), Chlorophyta (37%), Cyanobacteria (19%) and Euglenophyta (5%), whereas the least belonged to Mohammadabad pond, Euglenophyta (4%), Chlorophyta (36%), Cyanobacteria (21%) and Bacillariophyta (39%), respectively. The average density of phytoplankton in the water was 2.4× 106± 0.3×106 ind/lit and 3.8±0.3 mg/lit that showed no significant different among phytoplankton ponds (P>0.05), but there was significant different in phytoplankton abundance between three months (P<0.05). Average percentage of phytoplankton groups at both the beginning and the end of the gut contents of silver carp, included: Chlorophyta (43/11 and 38/33), Bacillariophyta (28.78 and 26.67), Cyanobacteria (21.67 and 28.11) and Euglenophyta (6.44 and 7.00), respectively. Maximum phytoplankton concentration present at the beginning and the end of the intestine of the fed fish belonged to Chlorophyta with 77% and 66%, respectively. As a result, most of the silver carp fed on Chlorophyta and Bacillariophyta group

Gahar Lake is an unique high-mountain lake, "Paternoster" form with glacial origin. There isn’t any research on the ecology of the lake, so in order to assess trophic status of small and great Gahar lake for the first time using TLI, the present study was conducted during a period of 1 year (except 3 months of ice period) from May 1389 to May 1390. Trophical parameters, Secchi depth (SD, transparency), chlorophyll a concentration and nutrients including Total Nitrates (TN) and Total Phosphorus (TP) was sampled monthly and zooplankton assemblage was measured. For statistical analysis of data in this study, we used the SPSS and Excel softwares. Based on the study of small Gahar lake, mean concentration of chlorophyll was 2.96µg.l-1, TN 801µg.l-1 and TP 25.3µg.l-1. In great Gahar lake, mean concentration of chlorophyll was 1.6µg.l-1, TN 976.5µg.l-1, TP 24.2µg.l-1 and mean value of secchi depth was 6.8m. According to TLI, the great Gahar Lake belongs to status of Mesotrophic level and the small Gahar Lake to Eutrophic level of the trophic scale.

In this research, water quality of Kalarood River of Babol was studied by identification of Macro invertebrate benthos. The result of this study was compared by ratio of EPT to Chironomidae and HFBI index. Six stations were selected and sampling was done seasonally for one year. Arthropoda and platy worm are the main branch of invertebrate benthos; in four class, eight order and eleven families. Maximum and minimum of diversity and density was observed in spring and summer in all stations, respectively. Also maximum and minimum of diversity was measured in station one and six, respectively. The relationship between physical and hydrological parameters were significant (p<0.05) in different season but it was not significant in different stations (p>0.05). HFBI index showed that minimum, maximum and average of this index was 3.99 in fall, 4.62 in spring and 4.33 respectively. The result of this study indicated that the water quality in the upstream was in normal range (good to medium condition) but in the other hand downstream and middle stream was in good condition.