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

Hydrology, Hydrobiology and environmental pollution in the southern of Caspian Sea

The project investigates the relationship between the biological parameters (phytoplankton, zooplankton, Macrobenthic and the comb jelly Mnemiopsis leidyi) and environmental parameters, nutrients and environmental pollutant (oil, pesticides, heavy metals, and detergents) in water and sediment, at the southern part of Caspian Sea in 2009-2010. Sampling was performed in four seasons (spring, summer, autumn and winter) and in eight transects perpendicular to the coast in Astara, Anzali, Sefidroud, Tonekabon, Noshahr, Babolsar, Amir Abad and Turkmen. Samples were collected from depths of 5, 10, 20, 50 and 100 meters and the different layers. The relationship between biological and environmental parameters surveyed through parametric and multivariate methods. Based on the result, the annual mean of environmental parameters and nutrients concentration at euphotic layer such as water temperature, salinity, pH, transparency, DO%, ammonium, nitrate, inorganic nitrogen (DIN), organic nitrogen (DON), inorganic phosphorus (DIP), organic phosphorus (DOP) and soluble silicon (DSi) were 17.82±0.32 (ºC), 11.35±0.10 (g/l), 8.43±0.01 (m), 126±1 (%), 3.76±0.19 (µM), 1.55±0.07 (µM), 4.81±0.13 (µM), 29.88±0.66 (µM), 0.24±0.01 (µM), 0.62±0.02 (µM), 8.22±0.22 (µM), respectively. Meanwhile, annual mean of environmental pollutant such as TPH, OCPs and LAS in water were 12.33±1.76 (µg/l), 2.85.0.90 (µg/l), 0.048±0.003 (mg/l), respectively and for TPH and OCPS in sediment were recorded 33.07±9.36 (µg/g) and 2.64±0.34 (µg/g), respectively. In addition, annual mean of heavy metals such as Ni, Hg, Pb and Cd at water were 4.01±0.01 (µg/l), 0.64±0.01 (µg/l), 15.0±0.1 (µg/l) and ND respectively, and in sediment were obtained 43.77±3.55 (µg/g), 0.13±0.29 (µg/g), 14.14±1.07 (µg/g) and 0.07±0.06 (µg/g), respectively. Abundance annual mean of biological parameters such as phytoplankton, zooplankton and M. leidyi were 143±12 (million cells/m^3), 6548±700 (individuals/m^3) and 86±10 (individuals /m^3) respectively, and for biomass were 548±41 (mg/m^3), 60±9 (mg/m^3), 5.06±0.65 (g/m^3). Abundance and biomass annual mean of macrobenthic were 5970±460 (individuals/m^2) and 44±10 (g/m^2), respectively. The stratification of water column was strongly based on gradient of water temperature and the rule of salinity was low in this area. According to mono and multivariate statistical analysis, the southern of Caspian Sea experienced four seasons without any overlapping based on environmental parameters and nutrients. In 2009-10, the nitrogen concentration was higher than previous years and showed a decrease in the amount of inorganic phosphorus in the study area. Therefore, the system has been lead to phosphorus limitation. No limitations of the DSi in the Caspian ecosystem had caused the dominance of bacillriophyta phylum during spring, autumn and winter. However in summer (highest seasonal mean temperature) which held the most DIP, the cyanophyta was dominant phylum. During spring and winter, the abundance of zooplankton was maximized and conversely the minimum values observed during summer and autumn with growth increasing of M. leidyi. By now, M.leidyi has been preferred the time with highest temperature or salinity during year. However with considering PCA analysis result and high ability of the organism to adaptation, the M.leidyi will probably to growth and reproduce at lower temperature and salinity than now in this area. Result showed that during summer and autumn only abundance of two of six main zooplankton groups namely Copepoda and Cirripedia were noticeable. The other zooplankton groups were low due to high consumption by different predators or were influenced by environmental factors. The dynamics population of M.leidyi is used to consider as first explanation of the Caspian ecosystem happening, however the interaction of different factors such as temperature, salinity, nutrients and predators determine the dynamic of biological parameters. Based on statistical analysis, feeding behavior of zooplankton species was not same in different seasons and was strongly dependent on the phytoplankton structure (species diversity and population). In other words, the classical boundary of phytoplankton species to, edible and suppressed, non-edible and unaffected and finally non-edible, enhanced species was not possible. Copepoda can act as filter-feeder and raptorial-feeder. So Copepoda compare to Cladocera (generally filter- feeder and sometimes raptorial feeder) and Rotifera (mostly suspension feeding and sometimes raptorial feeder) had more chances and opportunities for the achievement food and it support them for dominanane in all seasons. Anthropogenic and eutrophication effect on the structure and function of plankton community and it reflected on ratio of phyto/zoo biomass. Seasonal increasing of different groups of zooplankton were done through their life cycles in 2009-10, but mostly phytoplankton abundance increased several folds than zooplankton populations. This trend made the ratio of phyto/zoo biomass at 10, 4, and14 during spring, summer and autumn, respectively. In summer, with stratification of water column and dominant of Cyanophyta, grazing pressure by herbivores zooplankton was low. However in winter due to the zooplankton population growth, the ratios reached to 11, and declined with 1.3 folds compare to autumn. Because of severe decreasing of zooplankton biomass in 2009-10 compare to years before introduction of M.leidiy in to the Caspian Sea, the ratio of phyto/zoo biomass increased from "less than" 5 "to more than 10" Top-down control of zooplankton grazing on phytoplankton populations was clear in the years before the introduction of M.leidyi in to the Caspian Sea. But in 2009-10 zooplankton Shannon index reduced and phytoplankton Shannon index increased. In other word higher functional diversity at the lower trophic level (phytoplankton) increased the probability of successful defense against top-down control from zooplankton and phytoplankton abundance controled mainly by nutrients materials (down-top control). Seasonal macrobenthos abundance showed the maximum values in summer and minimum in the cold season (winter). The polychaeta had the highest proportion of abundance compare to others main orders (oligochaeta and crustacea). The dominance of deposit feeder species of polychaeta indicates to high level of organic matter in sediment and trophic status of ecosystem. Result of CCA analysis showed that three dominant orders had different behavior respect to environmental and sediments characteristics. The oligochaeta order was directly related to sediments characteristics (TOM) and inverse relationship with environmental parameters at most seasons. In contrast, polychaeta order was linked with environmental parameters in most seasons. Crustacea order was related to the both of them. Two orders of oligochaeta and crustacea were also related directly to OCPs and inverse relationship with TPH and heavy metals. In the other words, the two orders were more affected by TPH and heavy metals in this area. As a last point, increasing of trophic level from oligotrophic to the meso–eutrophic status, an increase of DO% from 105 percent to 120 percent, phytoplankton Shannon index increasing, zooplankton Shannon index decreasing, entrance of the potentially invasive species to the list of dominant phytoplankton species, increasing of phyto/zooplankton biomass ratio from less than 5 to more than 10 and also increasing of deposit feeder species abundance of macrobenthos are some evidences that indicate to disturbance and stress condition of the Caspian Sea

Microplastic particles in sediments and waters, south of Caspian Sea : frequency, distribution, characteristics, and chemical composition

This study assesses the occurrence of microplastics (MPs) in coastal and sea surface sediment, as well as water samples, collected from the coastal region of the southern Caspian Sea, Mazandaran province, Iran. A total of 32 sediment and 10 water samples were studied. The mean concentration of MPs was 15 units kg-1 in the sediments and 710 units m-3 in the coastal water. Fibers constituted by far the dominant MPs in both media, accounting for 97% of the MPs in both sediment and water samples. The MPs were mainly black in color. The dominant size of MP particles in sediment samples was between 250 and 500 µm, while the fraction >1000 µm dominated in the water samples. Polyethylene terephthalate (PET), polystyrene (PS), and nylon (NYL) were the main polymers and/or copolymers composing MPs in both sediment and water samples. The MP particles had a relatively smooth surface morphology, although signs of weathering were observed. The number of MP particles in sediment and water samples showed a general decrease from west to east in the study area. This may be reflecting the spreading of MP loading from the outlets of Sefidrud, Tonekabon, Chalus, the major rivers entering the Caspian Sea just west of the study area, and the overall decrease in the spatial distribution of touristic and fishery activity. The main sources of MP particles could be local emissions from a large number of domestic wastewater effluents and urban surface runoff due to high population density, and industrial and fishing activities in this region. This study indicated that MP particles, based on their characteristics and chemical composition, are circulated between coastal waters, and shore and sea surface sediments of the Caspian Sea, leading to their uneven distribution in the different depths. To the best of our knowledge, this is the first work studying the distribution of MP particles in sea surface sediments and also the most comprehensive on MPs in shoreline sediments and coastal waters in the southern Caspian Se

Eutrophication trend of southeast Caspian Sea water (Mazandaran-Goharbaran) based on environmental and biotic parameters using single and multiple variables in order to feasibility of marine cage culture

The aim of this project is to study water quality and the trophic status at different months and depths in the southeast Caspian Sea-Goharbaran based on environmental parameters and nutrients during 2013-2014 in order the feasibility of fish cage culture. Results showed that water temperature, transparency, pH, dissolved oxygen, BOD5, COD, total alkalinity and TSS were varied 9.00-29.00C, 0.50-12.00 m, 8.05-8.74, 5.76-12.85, 14-101, 21-195 and 0.00-0.12 mg/l at the different months and depths, respectively. In addition, the values of NH^4+, NH_3, NO^2-, NO^3- and PO^4-3 were 0.007-0.051, 0.001-0.010, 0.002-0.015, 0.043-0.477 and 0.014-0.077 mg/l, respectively. Chl-a concentration was recorded as 0.060-8.02 mg/l. Scaled and unscaled trophic indices were equal to 3.42-5.52 and 2.61-5.85, respectively. The proper temperature for cultivation of salmonids species in this area began from October to March. The range of the standard of pH and dissolved oxygen level for fish farming cage were 7.80-8.50 and >5 mg /l that in current study results of pH and dissolved oxygen which were consistent in the current study. Various forms of nitrogen (ammonium, nitrite and nitrate ) at the different layers were acceptable and less than the threshold limit of Australia and New Zealand. The results of the nutrients concentrations compared with data from the reference years (1996-1996 ) in the Caspian Sea (Goharbaran region) showed that this ecosystem passed from oligotrophic status and shifted to mezotrophic and eutrophic condition. As a conclusion, although nutrients concentrations were acceptable in terms of fish farming cages in this region, some parameters such as chemical oxygen demand and transparency are not suitable for aquaculture industry. Meanwhile, based on various trophic levels, this ecosystem (Gohrabaran region) has a mezotrophic status with a high risk of eutrophication

Hydrology, hydrobiology and environmental pollution in the southern Caspian Sea

The project investigates the relationship between the biological parameters (phytoplankton, zooplankton, Macrobenthic and ctenophore- Mnemiopsis leidyi) and environmental parameters, nutrients and environmental pollutants (oil, pesticides, heavy metals, and detergents) in water and sediment, at the southern Caspian Sea in 2010-2011. Sampling was carried out in four seasons (spring, summer, autumn and winter) and in eight transects perpendicular to the coast (Astara, Anzali, Sefidroud, Tonekabon, Noshahr, Babolsar, Amir Abad and Bandar Turkmen). Samples were collected from the different layers at depths of 5, 10, 20, 50 and 100 meters. The relationship between biological and environmental parameters surveyed through parametric and multivariate statistical methods. Result showed that the annual mean of environmental parameters and nutrients concentration such as water temperature, pH, transparency, DO, ammonium, nitrate, inorganic nitrogen (DIN), organic nitrogen (DON), inorganic phosphorus (DIP), organic phosphorus (DOP) and soluble silicon (DSi) at euphotic layer were 16.70±0.43 (ºC), 8.38±0.01 (m), 5.48±0.05 (ml/l), 1.52±0.06 (µM), 1.80±0.08 (µM), 3.41±0.10 (µM), 43.3±0.9 (µM), 0.32±0.01 (µM), 0.52±0.02 (µM), 8.88±0.22 (µM), respectively. Meanwhile, annual mean of environmental pollutant such as PAHs and OCPs in sediment were recorded 0.88±0.16 (µg/g.dw) and 9.78±2.20 (µg/g.dw), respectively. In addition, annual mean of heavy metals such as Zn, Cu, Ni, Pb and Hg in sediment were obtained 247±46 (µg/g.dw), 29.5±1.5 (µg/g.dw), 49.9±4.9 (µg/g.dw) and 0.179±0.800 (µg/g.dw), respectively. Annual mean abundance of biological parameters namely phytoplankton, zooplankton and M. leidyi (0-20m) at photic layer were 238±17 (million cells/m^3), 4808±362 (individuals/m^3) and 26±3 (individuals /m^3) respectively, and for biomass were 747±60 (mg/m3), 44.3±5.0 (mg/m^3), 2.15±0.31 (g/m^3). Annual mean abundance of those biological parameters at below of photic layer (50-100m) were 104±35 (million cells/m^3), 843±92 (individuals/m^3) and 2±1 (individuals /m^3) respectively, and for biomass were 412±93 (mg/m3), 9.1±1.0 (mg/m^3), 0.15±0.05 (g/m^3). Annual mean abundance and biomass of macrobenthic were 5073±1225 (individuals /m^2) and 144±73 (g/m^2), respectively. Annual mean annual percentage of TOM, Gravel, Sand and Silt-clay were recorded 3.74±0.26, 0.92±0.32 , 22.51±4.97 and 76.67±5.01, respectively. The stratification of water column was strongly based on gradient of water temperature and the phenomenon (difference of temperature between water layers) was more clear in this study compared to previous years. Temperature and biological factors (phytoplankton) were effected on changes of dissolved oxygen at warm and cold seasons summer and winter), but coefficient factor of temperature was higher than biological factors in winter. The nutrients concentration (with the exception of inorganic phosphorus) in different years 2008-2009, 2009-2010 and 2010-2011 increased compared to 1995-1996 (the year of stability of ecosystem). One of the reason attribute to the presence of the ctenophore (M. leidyi) in Caspian Sea after 1999. The annual correlation of phytoplankton abundance and temperature was reversed but seasonal pattern was varied at each season (within a year). In this study, the Caspian Sea contained the conditions of nitrogen limitation (55%) and nitrogenphosphorus limitation (6-43%) as well as phosphate limitation (2-39%) (DIN/DIP>20) . Inspite of no silica limitation (sufficient concentration of silica) in the Caspian ecosystem, Bacillariophyta was not dominance phylum at whole seasons.It seems that other factors such as the temperature changes of seasons, the effects of predation and feeding of the next chains of the food chain, the difference of the ability in the growth and reproduction, competition (uptake of nutrients) in dfferent groups of phytoplankton and stoichiometry of the nutrients (nitrogen and phosphorus) were caused of non-diatoms dominance at most seasons. As, Pyrrophyta and Bacillariophyta were dominant at spring and winter, respectively and Cyanophyta was pre-dominant at summer and autumn. Multivariate analysis showed the significant correlation between Coppepoda and oxygen and water temperature only. The other gropus of zooplankton did not show any significant correlation with environmental parameters. It might be due to stronger effects of other parameters such as food and predators on different groups of zooplankton at each season and abundance of zooplankton groups indirectly affected by environmental parameters. In this study, Shannon diversity indices of zooplankton and phytoplankton were closer to 1995-96 values and showed diferent trend compared to 2009-2010. However it is not enough reason for recovery of ecosystem in to the stability of Caspian Sea. It is because of other negative evidiance such as strong increasing trend of phytoplankton to zooplankton biomass ratio in all seasons and regions particularly the 2009-2010 and 2010-2011 years compared to 1995-96 (the year of stable ecosystem). In the other word, the balance between the biomass of the first and second of the food chain has been disturbed and the value was much much higher than the year of stable ecosystem in 1995-96. Based on multivariate analyses, there was not significant correlation between zooplankton groups and some edible phytoplankton species, vise versa zooplankton groups consumed some unsuitable species of phytoplankton (based on size, nutritional value, difficulty of digestion and absorption, the potential of toxicity and harmfulness). The lack of expected relationship and routine rules of nutritional between zooplankton and phytoplankton are the more resons of instability in the ecosystem. In current study, dominant group of macrobenthos (polychaeta) observed in depths less than 20 meters which the percentage of silt-clay and sand were 74 and 26, respectively. It seems that this ratio of silt-caly and sand was suitable for their living and accumulation. PCA analysis showed that increasing the percentage of TOM and siltclay accompanied to the decreasing of macrobenthos abundance while increasing the temperature, dissolved oxygen and pH had a positive effect on macrobenthos abundance in most seasons. Increasing the abundance of macrobenthos at all seasons (except spring) would not be a strong indication of improvement of Caspian ecosystem after the ctenophore introduction stress and unfavorable evidence such as low Shannon diversity index observe in the results. Meanwhile, in the present study, Streblospio and oligochaeta (invasive growth and advantage to the food uptake and habitat and sediment seeding) similar to the years of 2008-2009, 2009-2010 still were dominant groups insteade of Gammaridae family (feeding on suspended solids). This means that sediment has a noteworthy amount of organic matter which indicate to the trophic level of ecosystem tend to eutrophy level. The comparison of results on this study to previous studies on biological parameters (phytoplankton, zooplankton and macrobenthos) indicating to the persistence of stress (such as biological and anthropogenic) on their changing population patterns (quantitative relationships between species) and structural patterns (species composition and seasonal succession of dominant species). In other words, many species (both macroscopic and microscopic) of the Caspian Sea are still vulnerable to complications of stressor factors. In order to protection and sustainable exploitation of this worth ecosystem it is necessary to look more serious studies and practical techniques from the relevant organizations in this area

Study of physico-chemical Characteristics of water in the southern of Caspian Sea

This study was conducted to physico-chemical characteristics of water in the Iranian coastal of southern Caspian Sea during four seasons at 8 transects (Astra, Anzali, Sefidrud, Tonekabon, Nowshahr, Babolsar, Amirabad and Bandar Turkman) during 2009-2010. 480 samples were collected at different layers of water and then analyzed based on standard methods. Results showed that the mean of water temperature were 18.67±0.32 and 17.82±0.43 ◦C at the surface and euphotic layer, respectively. Minimum and maximum of water temperature were recorded in winter (6.40) and summertime (27.60). In addition, temperature gradient was ranged between 12 to 15 ◦C at 20 to 50 layers in 50 and 100m depths. Mean of salinity was 11.04±0.17 g/l at euphotic layer. Pearson correlation between temperature and salinity was positively significant. Therefore, maximum salinity was recorded in summer and minimum in winter. Mean of transparency (SD) in the present study was 4.35±0.21 m which compared to the pervious sampling period (2008) showed small decrease, but the mean of pH was observed 8.43±0.01 which was higher than the previous sampling period (2008). The mean of DO and DO% were observed 5.72±0.06 ml/l and 130±1 percent at euphotic layer during sampling period. The mean of DO% was recorded 104±5 at euphotic layer in 1996 (before introduction of Mnemeiopsis leidyi), but the study in the years 2004, 2008 and present (one decade after introduction of Mnemeiopsis leidyi) this value was registered higher than 120% at euphotic layer. This shows that trophic status of Caspian ecosystem shifted from oligotrophy (before introduction of Mnemeiopsis leidyi) to meso-eutrophy (after introduction of Mnemiopsis leidyi). Annual concentration of inorganic nitrogen (DIN= NH^4 +, NO^2-, NO^3-) has a fairly wide variation. Percentage of nitrogen components out of DIN were varied 9-98, 0.2-28.2 and 0.0-90.0 respectively. In this study, percentage of DIN was lower than 15% and organic nitrogen (DON) was higher than 80%. Overall, results showed that water temperature, salinity, transparency and DON were recorded lower than the previous study (2008), but DO, DO%, pH, NH^4+, NO^3- and DSi were higher than the previous sampling period. Inorganic phosphorous (DIP) and NO^2- have not changed substantially. N/P ratio of Caspian Sea has a narrow range which order of magnificent lower than other seas. The results of the present study showed that Caspian ecosystem was nitrogen limitation before introduction of Mnemiopsis leidyi, while it seems that after introduction of Mnemiopsis leidyi the system has been shifted to the phosphorous limitation

Study on some physico-chemical parameters in the southern of Caspian Sea- Mazandarn Province

This study was conducted to determine physico-chemical characteristics of water and their spatial and temporal fluctuations in the Mazandaran coastal of Caspian Sea in 6 months, four seasons at 4 transects (Tonekabon, Nowshahr, Babolsar, Amirabad) during 2012-2013. 72 samples were collected at surface layer of water in 5, 15 and 30m depths. Then the sampls analyzed based on standard methods. Results showed that the mean of water and air temperature were 19.46±0.85 and 20.25±0.78◦C, respectively. Minimum and maximum of water temperature were recorded in winter (7.00) and summer time (28.10). Mean of salinity was 12.35±0.13 ppt. The maximum salinity was recorded in summer and minimum in winter in all transects. Mean of transparency (SD) in the present study was 2.63±0.18m. The mean of pH was observed 8.51±0.02 which was higher than the previous sampling periods. The mean of DO was observed 6.00±0.07 ml/l during sampling period. Annual concentration of dissolved inorganic nitrogen (DIN= NH4 +, NO2-, NO3-) has a fairly wide variation in different months and transects. Percentage of nitrogen components out of DIN were varied 6-53, 0.14-26.0 and 37.0-94.0 respectively. In this study, percentage of DIN was lower than 15% and dissolved organic nitrogen (DON) was higher than 80%. Mean of annual dissolved inorganic phosphorous (DIP) and organic phosphorous were 0.58± 0.04 and 0.48± 0.02 µM, respectively. DIP and DOP percentages recorded 54 and 46 respectively. Mean annual of dissolved silicon (DSi) obtained 9.5± 0.2 µM. Based on the results, the system was in phosphorus limitation during spring and summer but it shifted to nitrogen limitation in autumn and winter. Phytoplankton development was not limited by DSi at any seasons

Determination of sediment nutrients in the cage fish culture area (before breeding) of the southern Caspian Sea (Mazandaran coast-Kelarabad)

This study was conducted to determine phosphorous and nitrogen species at the surface sediment in the southern Caspian Sea (Mazandaran Coast, Kelarabad). Surface sediments samples were collected at three stations from autumn of 2011 to winter of 2012. All samples were prepared by digesting and extracting processes and then phosphorous and nitrogen species concentrations determined using spectroscopy instrument. Results of this study showed that annual mean of Loosely-P, Fe-P, Al-P, Bioava.-P, Ca-P, TIP, Rese.-P and TP was obtained as 5.06±0.33, 55.11±2.52, 42.38±3.74, 102.52±5.68, 172.91±7.12, 275±9.12, 333.30±28.52 and 608±52 µg/g.dw, respectively. The results also showed that inorganic phophorous was less than organic phophorous during different seasons, however, mean percentage of residue-P containing organic compounds and non-degradable compounds was more than 50 percent. Percentage of Ca-P was higher than 60, whereas Bioava.-P was less than 40 percent. In addition, Fe-P and Loosely-P attained the maximum and minimum values, respectively, among the bioavailable phophorous. The order of different forms of phosphorous were recorded as Org-P>Ca-P>FeP>Al-P>Loosely-P. Annual mean of NH4/N, NO2/N, NO3/N, TIN, TON and TN were observed as 4.23±0.50, 0.06±0.01, 0.74±0.12, 5.02±0.53, 2.48±0.63 and 7.53±0.51 µg/g.dw, respectively. Annual percentage of TIN was two folds than TON and concentration of NH4/N was also four times than NO3/N. As a conclusion, the results revealed that main causes of Bioava.-P adsorption and desorption were temperature, Eh and pH. Also, the form of NH4+/N was of a high percentage because of anaerobic condition in the sediments. According to the high ratios of nitrogen/phosphorous of sediments to nitrogen and phosphorous of bottom water, it finds that released of those from the sediments to water will be happened with high rates. Therefore, it is expected that the establishment of fish farming cages should be carried out with more precautionary approaches which not leads to increased algae bloom

Determination of water quality characteristics of Shahid Rajaei reservoir (Sari) based on physic-chemical parameters

The water quality provides the valuable information about the available resources for human usage. The reservoirs are the important resources of surface water which could be considered as an appropriate water resource for irrigation, drinking water and also fish culturing. The Shahid Rajaei Reservoir- Sari is an important reservoir in Iran, which conducted to study on its water quality in this survey. In this study, some of the physicochemical parameters and Chlorophyl- a of Shahid Rajaei reservoir were measured at 4 stations (Shirin Roud branch, Sefid Roud branch, the crossing point of branches, near the tower) during six sampling months (June, July, August, September, November and February) in 2012-2013. The water quality and trophic status of reservoir calculated based on some reference values and the modified Carlson formula. The results showed that the mean (±Standard Error) of temperature, dissolved oxygen, pH, phosohate, amonium and nitrate concentrations and Chlorophyl a were 21.35 (±1.30) ºC, 10.48 (±0.37), 8.54 (±0.04), 0.050 (±0.004), 0.036 (±0.004), 0.75 (±0.03) mg/l and 18.00 (±7.23) mg/m^3 , respectively. In the present study, temperature between surface and deep layer was stratified in June and July, which the stratification was registerd 0.47 and 0.69 °C decreases with increasing of each meter depth in 15 to 30 meter culumn. But, these changes for each increasing meter of water depth were 0.2 to 0.26 °C in August and September, respectively, and finally was close to zero in November. In the warm months (July, August and September) with the formation of thermal stratification in the reservoir was formed oxygen stratification, but in the cold season (November and February), with vertical mixing of water oxygen and percent saturation of the reservoir was nearly homogeneous. The results showed that the European authorities (OECD) trophic status varied between mezotrophic to hypertrophic during the sampling period at all stations. The comparison with the values listed in the references of Iranian dams based on transparency and chlorophyll variables showed similar results. However, phosphorus variable (due to limited for phytoplankton) was not showing the true conditions of trophic status. As a conlusion, trophic status of Shahid Rajaei dam based on Carlson trophic index (TSI) was obtained oligotrophic (May and October), mezotrophic (February) and eutrophic (August and September) condintion during diferent months. Therefore, water management of the reservoir was more attention during warm months

A study on water quality and physio- chemicals parameters in surface water, underground water and wastewater of Mangol dam basin (Mazandaran province)

This study was conducted to determine water quality of surface water (7 stations), ground water (5 stations) and wastewater (4 stations) at Haraz River during instruction of Mangol Dam in 2009-2010. This study is to follow physico-chemical fluctuation of waters and compared the data obtained with previous studies and standard levels. Results of current study showed that annual mean with standard error of temperature, DO, BOD_5, COD, HCO^3-, CO_3^2-, TA, Ca^2+, Mg^2+, TH, TSS, TDS, Cl^-, PO_4^3-, NH^4+, NO2- and NO3- were observed 12.7 (±0.61) centigrade, 10.13 (±0.12), 2.1 (±0.1), 7.71 (±0.99), 28.1 (±6.1), 14.34 (±1.64), 36.30 (±2.33), 64.66 (±2.34), 28.84 (±1.52), 271.62 (±8.41), 0.37 (±0.03), 0.30 (±0.02), 28.02 (±1.96), 0.06 (±0.01), 0.010 (±0.001) and 0.94 (±0.03) mg/l, pH was 8.00 (±0.02) and EC 0.50 (±0.02) ms/cm in surface water. The annual mean with standard error of temperature, HCO^3-, CO_3^2-, TA, Ca^2+, Mg^2+, TH, TSS, TDS, Cl^-, PO4^3-, NH^4+, NO^2- and NO^3- were observed 21.62 (±1.03) centigrade, 54 (±5), 11 (±5), 57 (±5), 208.6 (±42.5), 109 (±23), 1088 (±165), 0.065 (±0.017), 0.97 (±0.11), 317.8 (±76.2), 0.25 (±0.06), 0.06 (±0.01), 0.0007 (±0.0001) and 0.78 (±0.05) mg/l, pH was 7.37 (±0.07) and EC 1.98 (±0.23) ms/cm in underground water. In addition, the annual mean with standard error of temperatute, DO, BOD5, COD, TSS, TDS, and NO3- were observed 12.7 (±0.61) centigrade, 13.59 (±0.87), 9.80 (±0.12), 2.22 (±0.18), 7.54 (±1.02), 0.50 (±0.03), 0.320 (±0.008) and 0.990 (±0.016) mg/l, pH was 7.95 (±0.02) and EC 0.64 (±0.01) ms/cm in wastewater. Quality of surface water of Haraz River and its branches were almost contained suitable for usual applications, but sometimes the quality of surface water based on BOD5 need to more attention for man uses (such as supply of drinking water). In addition, the quality of surface water was relatively suitable for aquatic based on the aquatic standard levels. Results also showed that water quality index (WQI) was declined from upstream to downstream and some parameters were not in standard ranges. The quality of surface water classified in group II at all stations based on water classification rules which it shows serious water quality changes due to environmental destroyed and domestic, agriculture sewage pollutions. Groundwater were affected by different springs at middle and downstream which they caused change physico-chemical characteristics and water quality. Wastewater was classified from good to moderate based on BOD5. The quality of wastewater was declined at downstream with decreasing DO and pH and increasing BOD5 and pollutants