The quantitative changes of silicon and diatoms in southern part of Caspian Sea

The purpose or this study was to evaluate the changes of dissolved silicon concentration and biomass of diatoms in southern part of Caspian Sea, 1270 plankton and water samples were collected seasonally from 77 stations for further quantitative and qualitative analysis.The results showed that the minimum and maximum density of dissolved silicon and biomass of diatoms were varied from 0.195 to 0308 ppm and 33 to 179 mg/m3 respectively. As well as the fluctuation of dissolved silicon concentration in different depths of photic zone. It was indicated that the maximum and minimum concentration of this element were found in the eastern area with 0.269 ppm and western area with 0.180 ppm. The most and the least biomass of diatoms were observed in the western and central areas with 180 and 89 mg/m3, respectively. The concentration or silicon in offshore waters was more than coastal waters and on the contrary, the biomass of diatoms from coastal to offshore waters indicated decreasing trend. In a conclusion, the concentration of dissolved silicon and biomass of diatoms could be affected by different physical parameters such as: water circulation, river currents, exchange of biogenic sediments in photic and aphotic zones. Also, there was a significant relationship between the biomass of diatoms and silicon concentration

Monitoring on algal bloom event in the southern of Caspian Sea

Nutrient enrichment is followed by excessive algal growth (possible in toxic and harmful species); in Caspian Sea in recent decades. So aims of the present study were 1-study on potential of algal bloom at different transects and seasons, 2- determine correlation between potential of algal bloom and environmental parameters using statistical model, and 3- the role of sediment nutrients on algal bloom in the southern Caspian Sea in 2013-2014. The samples of water were collected from four transests (Bandar Anzali, Tonekabon, Bandar Nowshahr and Bandar Amirabad) and three depths (5, 10 and 20 meter) during four seasons. Surface sediments samples were collected at same depths and transects as well. Result showed that organic phosphorous and nitrogen of water were more than inorganic phophorous and nitrogen. Also, maximum and minimum water temperature was obtained at summer and winter, respectively. The values of DO and salinity were more than 5 ml/l and 12 g/l, respectively and pH of water were ranged from weak alkaline to alkaline. Maximum organic and inorganic phosphorous and nitrogen of water were distributed at different transects and seasons. The nitrogen was limiting factor accomponing with phosphorous during spring, summer and fall, but during winter shift to more nitrogen limitation. In addition, the ecosystem was experienced sillicon limitation during winter. Result of sediments showed that inorganic phophorous was maximum during different seasons, however, percent mean of residue-P which contain organic compounds and non-degrediable compounds, was less that 5 percent. Percent of Ca-P was higher than 90, whereas Bioava.-P was less that 10 percent. The order of different forms of phosphorous were registered Ca-P>Org-P>Fe-P>Al-P>Loosely-P. The mian role of adsorbed and desorbed of Loosely-P, Fe-P and Al-P were due to temperature, Eh and pH, respectively. Annual percent of TON was two folds than TIN and NH4/N was also three times than NO_3/N. Minimun and maximum of phytoplankton abundance were obserbed in summer (73±31 million cells/m3) and winter (505±55 million cells/m3), respectively. Statiscal analysis (ANOVA) showed that phytoplankton abundance significantly increased in winter compared to the other seasons (P1000 cells/ml) during spring. Maximum abundance of phytoplankton was mainly registered at Anzali and Amirabad transects.The re-existence of Thalassionema nitzschioides (as valuble food in food chain) in dominant species list (same as the stability year of ecosystem) and decreasing of percent abundance of harmful species to the dewell and native species are good sign of good quality of the Caspian Sea water. However, Pseudonitzschia seriata expansion of the cold season to other seasons (even in summer) is important point. Pseudonitzschia seriata as harmful algae and its ability to produce toxin and potential bloom, high percent frequency and abundance during the study has important role in environmental issues of the Caspian Sea.It seems that temperature changes in different parts of the Caspian Sea in each season (except fall season) was obtained in the range of dominant species needed, therefore, it had less importance compared to nutrients. Trophic status was meso-eutroph during fall and winter seasons which was higher level than spring and summer (mesotroph). The Stephanodiscus abundance increased at Anzali transet due to nutrients enrichment of water in spring. Excessive use of silica in the spring, summer caused dominant of non Diatoms species (Binuclearia lauterbornii) and low content of Diatoms species (Chaetoceros throndsenii). In fall, high abundance of Bacillariophyta (Thalassionema nitzschioides) accompanied with consuming of silicon and ammonium. The statistical analysis also showed significant correlation between Bacillariophyta and Thalassionema nitzschioides abundance and Si/N ratio. Subsequently, the excessive use of silica in autumn and winter (due to high abundance Bacillariophyta and dominant species including Pseudonitzschia seriata and Dactyliosolen fragilissima) cause severely declined dissolved silica, and for the first time in winter, silicon was limited factor for phytoplankton growth. In addition, the results showed that there were positive correlations between abundance of dominant species and nutrients of sediments in all seasons. This is shows that some species of phytoplankton, even though the limitation of nitrogen and phosphorus in the water, are able to supply the nutrients required from the surface sediments. It would be more importance in the present study, which higher concentration of different forms of phosphorus and nitrogen in sediments as compared to the deep water, provide transport of nitrogen and phosphorus from sediment to water column

Feeding investigations of silver carp (Hypophthalmichthys molitrix) fingerlings with emphasis on dominant phytoplanktons

In order to study phytopague fingerlings feeding in fish ponds, simultaneously to the beginning of warm season and cultivation, fingerlings of 3-5 gr from 4 ponds in Mazandaran province were captured, fixed with formalin, then transferred to the plankton determination laboratory of Caspian sea ecologic institute. Based on carried out studies on the first and the end party of their intestine and the pond water, phytophague fingerlings feeds on phytoplankton, zooplankton and detritus. But the essential nutrition was on phytoplankton and detritus. Planktonic groups were formed of Cyanophyta, Chlorophyta, Chrysophyta and Euglenophyta. But in addition to these four groups Pyrophyta was present in fish pond water. Relative abundance of these nutrient organisms in water and intestine was different. Also in most cases a direct relation was observed between the intensity of water organisms and intestine ingredients. Based on this study, essential differences of digestion were observed following to the source of nutrition and the most difference were considered in digestion of Chrysophytes, Cyanophyta and Chlorophyta. Base on the results of this study we propose to make more studies on fertilization and the proportion of different fertilizers in fish ponds in order to obtain easily digestible phytoplankton thus increase in fish exploitation

Survey of diversity, distribution, abundance and biomass of macrobenthic fauna in the southern Caspian Sea

Sediments samples were collected using Veen Grab Sampler (0.1 square meter) at 8 transects namely Astara, Anzali, Sefidroud, Tonekabon, Noshahr, Babolsar, Amirabad, Torkman in the southern of Caspian Sea. Five stations were selected at 5, 10, 20, 50 and 100 meter depths in each transect. Sediments were sampled triplicate at each station. Samples also were collected during four seasons (spring (May), summer (July), fall (November) and winter (January)) in 2009. Results of this study showed that species composition of Macrobenthos consisted of 32 species which belonged to 7 families of Polychaeta, Crustacea and Bivalvia at studied area. In addition, Oligochaeta identified in “Class”, Chironomidae considered in Insecta categories “Family” and Streblospio spp. (Polychaeta) was recognized in “Genus”. Gammaridae and Pseudocumidae of Crustacea with 12 and 10 species had the highest species diversity compared to other groups, respectively. Polychaeta was consisted 75.5 percent of total abundance of macrobenthos which the major abundance (equal 62.4% of total abundance) were belong to Streblospio spp. from Spionidae family, while its biomass was equals 5.11% of total macrobenthos. In contrast, Cerastoderma lamarcki species from Bivalvia Class with only 1.7% of total abundance of macrobenthos allocated 69 percent of total biomass. In the southern of Caspian Sea, average total abundance was significantly less at 4 western transects (Astara, Anzali, Sefidroud, Tonekabon) compared to 4 eastern transects (Noshahr, Babolsar, Amirabad, Torkman) (p<0.05). The highest average abundance of macrobenthos (10655±1246SE ind/m^2) was observed at transect of Torkman, and lowest value (4032 ± 686SE ind/m^2) was recorded at transect of Sefidroud (p< 0.05). Generally, minimum species diversity were obtained at 20 m depth in all transects and the maximum value was observed at 5 m depth in most of transects (p<0.05). In contrary, maximum average abundance of Macrobenthoses was at 20 m depth in transects of Anzali, Sefidroud, Tonekabon, Nowshahr and Amirabad compared to other depths. Macrobenthoses abundance average in 5 m depth (except Astara and Torkman) was less than other depths in 6 transect (p < 0.05). Total average abundance and biomass of macrobenthos was 5976±583SE ind/m^2 and 43.675 ± 11.402SE gr/ m^2, respectively. Maximum and minimum of abundance of macrobenthos were observed in summer (7714±778 ind/m^2) and winter (4071 ± 340 ind/m^2), respectively. Maximum and minimum of biomass of macrobenthos were obtained in fall (50.271±13.258SE gr/ m^2) and in summer (35.123 ± 8.903SE gr/ m^2), respectively (p< 0.05). Percent of total organic matter (TOM) were low in 5 and 10 m depths and increased toward offshore depths. TOM percent was 2.06±0.11SE at 10 m depth and increased to 4.62 ±0.17SE in 100 m depth. Percent of silt and clay (grains size less than 63 micron) had positive significantly correlation with percent of TOM (p<0.01).While they had negative significantly correlation with percent of sand (grains size between 63 and 1000 micron) (p<0.01). Percent of silt and clay like organic matter, had ascending trend toward to depth increased and varied from 44.4 ± 4.06SE percent in 5 m depth to 96.5 ± 0.59SE percent in 100 m depth. In contrast, percent of sand decreased toward depth and varied from 54.5 ± 4.13SE percent in 5 m depth to 2.8 ± 0.53SE percent in 100 m depth. Result of current study showed that total abundance of macrobenthoses had positive significantly correlation with TOM percent (p<0.01) and silt/clay percent (p<0.05). Abundance of Oligochaeta had positive significantly correlation (p< 0.01) with TOM and silt/clay percent. Two groups of Polychaeta, Gammaridae and Cerastoderma lamarcki had negative significantly correlation with TOM and silt/clay percent (p< 0.01), and every four aforementioned groups had positive significantly correlation with sand percent (p< 0.01). Overall, different correlation between abundance of various macrobenthos groups and TOM percent and type of grain size of sediment could be related to fluctuation of abundance of various macrobenthos groups at difference transects and depths. On the other hand, in study area were occurred simultaneously some phenomena such as increased abundance of Oligochaeta and Polychaeta, dominance of Streblospio Genuse (Polychaeta group), and decreases abundance of Bivalvia and appearance of Menemiopsis leidyi which need to study more and monitoring of this area

Quantitative assessment of biopllution caused by Mnemiopsis leidyi on ecological community structure in the southern part of the Caspian Sea

After the arrival of the invasive spexies (Mnemiopsis leidyi) in the ecosystem of Caspian Sea in 1999, It had notable impacts. In this study, we,re assessing impacts of quantitative M. leidyi as a biopllutant on zooplankton community in the southern part of the Caspian Sea during 2001-2010 period. It becomes clear that Abundance and Distribution Range (ADR) of M.leidyi during 2001-2009 was in class E(occurrence in high numbers in all localities) and in year 2010 was in class D(occurrence in moderate numbers in all localities). from 2001- 2009, ADR in Summer season was in class E, but in summer 2010, relatinve biomass of M.leidyi has decreased and ADR was evaluated as D. During the fall seasons of 2001 -2010, only in fall of 2003 and 2010, the ADR was C(occurrence in low numbers in all localities) and D respectively and in other years, the ADR was in class E. In winter season relative biomass of M.leidyi decreased and only in winter of 2001 relative biomass was high and the highest ADR (class E). In winter 2003 and 2004, ADR was in class D. The biomass of M.leidyi was found to be zero in winter 2008. From winter of 2009-2010,ADR, were assessed B and A respectively. In the spring, ADR was evaluated A and D. Considering the obtained results, the yesr 2001, which the relative niomass was more than 90 percent, could be considered as the expantion phase and the following years (2002-2010) with regard to decrease of relative biomass as the adjustment phase. With regards to the loss of the keystone species (Eurytemora sP.) and some other native species, our evalution showed that the impact of M.leidyi on structure of zooplankton community was assessed as massive (C4).During summer and fall seasons that biomass of M.leidyi was higher than 50%, only A.tonsa exist, but during spring and winter seasons that biomass of M.leidyi was decreased and more species have a chance to exist

Quantitative evaluation and identification of fungi in Shahid Rajaeii Dam Lake, Mazandaran Province (Sari)

The present study is carried out to investigate the fungal species present in water of Shahid Rajaeii damlake in Sari, (Mazandaran province). Samples were taken from five stations including, Station 1: Input of Shirinrud river, station 2: Input of Sefidrud river, Station 3: The confluence of the two branches, Station 4: dam crest and stations 5: Output dam from June to February 2012. Every sample was diluted by sterile saline (10-1 and 10-2) and 0.5 mL from each dilution was cultured on SD and incubated at 27-30°C for 3-5 days. Finally, the number of colonies wasrecorded as (colony forming unit = CFU) per 100 mL. Identification of fungal agents were conducted by slide culture preparation and stained in lacto-phenol blue. The results showed that in August and February were significantly highest and lowest rates of fungal colonies were isolated from water in different stations respectively. Moreover, the number of fungal colonies in the crown and the output was significantly higher than other stations. The frequency of identified fungi were: Aspergillus species (31.4%), various types of yeast (mainly Candida) (24.2%), Penicillium sp. (19.3%), Cladosporium sp.(10.3%), Mucor sp. (5.4%), Fusarium sp. (2.9%), sterile hype (2.8%), Alternaria sp. (2.3%) and Paecilomyces sp. (1.4%)

Study on macrobenthic communities in the range of fish cage-culture area (before breeding) in the southern Caspian Sea (Mazandaran coast-Kelarabad)

The abundance and biomass of benthic macroinvertebrates were studied in the place of fish cage culture in southern coasts of Caspian sea (Mazandaran waters- kelarabad). The goal of this study was to consider of fish cage culture effects on the abundance and biomass of benthic macroinvertebrates. The sampling was carried out in 3 stations in depth of 20 meter of Kelarabad waters monthly. In this study 7 species were identified belonged to 5 genus of 4 family. Totally 23442 sample of benthic invertebrates were counted that the lowest and highest abundance were in station 1(23.4%) and station 2(46.8%) respectively. The results of stations study showed that the highest abundance and biomass were in stations 2 and 3 with the average of 646 ± 1230.4 n/m^2 and 0.526 ± 1.001 gr/m^2 respectively. This coulld be respectively dependant to not settling of cage (witness station) and appearance of Cerastoderma glaucum because of its large body in station 1. The difference of abundance and biomass between different stations was not significant (p ›0.05). The study on abundance and biomass in different seasons showed that the highest abundance in autumn with the avarage of 888.13 ± 1371.58 n/m^2 belonged to Strblospio gynobranchiata and the highest biomass belonged to C. glaucum which was because of appearance of not native species of polychaeta and also the species with shell covering from bivalvia. The results showed that the specie of S. gynobranchiata from polychaeta including 93.3% of abundance was the dominant specie that could be related to appropriate ecological conditions for living and high adaptability. It was concluded that the abundance and biomass of benthic macroinvertebrates in station 1 was lower than other stations which was related to fish cage culture activity and its effects on benthic macroinvertebrates. So it is suggested that each mariculture activity in southern coasts of Caspian Sea should be carried out with regarding to environmental considerations and performance of comparative evaluation project of environmental effects

Designing and establishment of ISO/IEC 17025 in 3aboratories of Caspian Sea ecological research center

The project was carried out between March of 2007 and November of 2009.Five laboratories of research center (Clinical pathology, Plankton, Molecular genetics, Pollutants, Analysis Instrument were selected for accreditation. The main stages for establishment of the system consisted of: 1-Conducting a gap analysis to compare the present state of the laboratories with ISO/IEC 17025 Training 2 General requirements for the competence of testing and calibration laboratories Validation of methods Estimation of uncertainty Internal audits 3- Performing of technical and management requirements 4-Submit of quality manual to Iran Accreditation System (IAS) in order to accredit In January of 2010 the laboratories were accredited by Iran Accreditation System (IAS). The main results were including: 1-Increase the accuracy of measurement 2-Improvement of the Repeatability and Reproducibility of the test methods 3-Traceability and standardization of test methods 4- Calibration of measurement instruments 6- Updating of test methods 7-Standardization of physical condition of the laboratories 8- Getting the certification from Iran Accreditation System (IAS)

Protective effects of Nasturtium officinale against gamma-irradiation-induced hepatotoxicity in C57 mice

Background and objectives: Nasturtium officinale W.T.Aiton (Brassicaceae) is used as an edible vegetable in various parts of Iran. The aim of the present study was to investigate the protective activity of the methanolic extract of Nasturtium officinale against gamma-radiation-induced hepatotoxicity in terms of histopathological changes. Methods: Male C57 mice were divided into 10 groups. Groups 1 and 2 received saline solution intra-peritoneally (IP) for 15 days (subacute) and 2 h (acute) before whole body γ-irradiation (6 Gy). Groups 3 to 5 (subacute) and 6 to 8 (acute) received the extract at doses of 20 mg/kg, 50 mg/kg and 100 mg/kg body weight IP, respectively. Group 9 served as radiation group. Group 10 received nothing. Finally, sections of the liver tissue were evaluated for any histopathologic changes. Total phenolic and flavonoid contents were determined using Folin Ciocalteu andaluminium chloride methods. Results: Pre-treatment with 100 mg/kg body weight per day for 15 days and 2 h before γ-radiation significantly lowered incidence of inflammation (portal and periportal inflammation). Furthermore, liver cells necrosis, edema and congestion were slightly reduced. The total phenolic and total flavonoid contents of the extract were 11.3 ± 0.4 mg gallic acid equivalents and 9.4 ± 0.7 mg quercetin equivalents per gram of dried extract. Conclusion: This protection can be attributed to the presence of phenols and isothiocyanates in the extract of N. officinale which act as antioxidants and anti-inflammatory agents