Recursos de colección

Aquatic Commons (41.069 recursos)

The Aquatic Commons is a thematic digital repository covering the natural marine, estuarine /brackish and fresh water environments . It includes all aspects of the science, technology, management and conservation of these environments, their organisms and resources, and the economic, sociological and legal aspects.

Subject = Environment

Mostrando recursos 1 - 20 de 53

  1. Spatial and temporal patterns of benthic macrofauna in Gorgan Bay, south Caspian Sea, Iran

    Ghorbanzadeh Zaferani, S.Gh.; Machinchian Moradi, A.; Mousavi Nadushan, R.; Sari, A.R.; Fatemi, S.M.R.
    We quantified the distribution, abundance and assemblage structure of macrofauna at 22 stations in Gorgan Bay, seasonally in 2012-2013. Also, depth, temperature, salinity, DO, TOM and sediment particle size were measured in each station. The highest concentration of TOM was measured near the western littoral zone (10.22) while the mouth part and north-eastern area was characterized by the lowest values (2.65 % and 4.69). A total of 31658 individuals belonging to 12 families and 14 species were identified. Polychaeta with 3 species was the most dominant group in terms of abundance. The four most abundant taxa making up 85% of...

  2. Assessment of cadmium and lead in the water and trout fish (Salmo trutta) of Zayandehroud River, a case study of Zarinshahr rice farms, Isfahan

    Moradi, S.; Nowzari, H.; Farhadian, M.
    This study aimed to investigate the concentrations of two heavy metals, lead and cadmium, in the water of Zayandehroud River which is surrounded by Zarinshahr rice farms. Water was sampled from a depth of 30 cm during June, July and August 2015, i.e. during the process of planting, growing and after harvesting, in three stations. Water was collected from three points; 20m before the farms, beside the farms and 100m after the farms. Three water samples and one trout fish (Salmo trutta) sample were collected each month and the concentrations of lead and cadmium were measured in the kidney, liver...

  3. Biomonitoring of trace metal bioavailability in the barnacle Amphibalanus improvisus along the Iranian coast of the Caspian Sea

    Nasrolahi, A.; Smith, B.D.; Ehsanpour, M.; Afkhami, M.; Rainbow, P.S.
    The fouling barnacle Amphibalanus improvisus is a cosmopolitan biomonitor of trace metal bioavailability in coastal waters of reduced salinity such as estuaries or the Baltic Sea. Bioavailability of Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn to A. improvisus was investigated in July 2014 at 15 sites along the Iranian coast of the understudied, yet biologically unique, Caspian Sea. In general, the bioavailability of these toxic metals in the water column, as biomonitored by the barnacle, was within the typical ranges expected from data available in the literature. Thus, there were no major environmental concerns...

  4. Short communication: Ecological larval fish groups in Chabahar Bay in relation to day/night and monsoon variations

    Nasiri, H.R.; Rabbaniha, M.; Attaran-Fariman, G.; Mousavi Golsefid, S.A.
    Studies on larval fish abundance allow important inferences about the spawning grounds, reproduction season and migration pattern of fishes. Larval densities can also be used to estimate the abundance index, which in turn can be correlated to the fisheries yield, and provide an alternative approach for measuring the size of the spawning stock. Previous studies in this ecosystem have focused on the abundance of fish larva without consideration of daily fish larva variations. ... In this research we consider the monsoon as an important phenomenon, affecting the daily fish larval distribution.

  5. Environmental effects of the cold water fish farms effluents on the water quality of Gamasyab River as their main source of water supply in the west of Iran

    Danesh pajooh, R.; Reyahi Khoram, M.; Cheraghi, M.; Mohamad Poor Roodposhty, G.A.
    Rainbow trout (Oncorhynchus mykiss) is one of the most-widely cultivated cold fresh water fish in the world. Gamasyab River, with a length of about 200 Km, is one of the longest rivers of Iran. The aim of this research is to determine the effects of trout farm effluents on this river water. From a total of 24 trout farms in the area, four farms were randomly selected and three sampling stations were chosen at each selected farm. Measured water quality parameters were temperature (T), total suspended solids (TSS), total dissolved solid (TDS), dissolved oxygen (DO), pH, five-day biochemical oxygen demand...

  6. Phytoplankton of Aras dam reservoir (Iran): an attempt to assess water quality

    Mohebbi, F.; Riahi, H.; Sheidaei, M.; Shariatmadari, Z.
    The Aras reservoir, located in the north-west of Iran, plays an important role in fisheries, drinking and agricultural water supplies and recreational activities in the region. This study was performed to characterize the seasonal fluctuations of phytoplankton communities and their relationship with environmental factors in the Aras reservoir from August 2013 to May 2014. Sampling was carried out seasonally from 5 sampling locations. In each location three samples were taken for phytoplankton identification and enumeration, chemical analysis and chlorophyll a determination. In total, 72 species belonging to 5 divisions were determined. Cyanobacteria contained the highest density (74%) during the study...

  7. Off-shore disposal of chemical agents and weapons conducted by the United States

    Compilation of 73 disposal sites in the Atlantic Ocean, Pacific Ocean, Mediterranean Sea, Indian Ocean, and U.S. rivers and lakes, 1918-1970.

  8. Acclimation responses of gill ionocytes of red tilapia (Oreochromis mossambicus × O. niloticus) to water salinity and alkalinity

    Jeerawat Thammaratsuntorn, J.; Zhao, J.L.; Zhao, L.H.; Zhuang, Q.Q.; Guo, J.T.; Larbi Ayisi, Ch.
    To understand the acclimation strategies of red tilapia to different environments, this study aimed to evaluate different responses of red tilapia (O. mossambicus × O. niloticus) to salinity (10-30‰), alkalinity (1-3 gL^-1 NaHCO3) and salinity and alkalinity (10/1-30/3 ‰/gL^-1 NaHCO3) environments. Localization, type, size, and numeration of gill ionocytes were investigated on the same specimens by scanning electron microscopy (SEM) and immunohistochemistry (IHC) with antibodies of Na+/K+-ATPase (NKA), Na+/K+/2Cl-contransporter (NKCC), cystic fibrosis transmembrane conductance regulator (CFTR) and carbonic anhydrase (CA). Ionocytes were only located on filaments conducted by SEM. Four types of ionocytes namely pit, convex, concave and transitory types...

  9. Water quality assessment in Choghakhor Wetland using water quality index (WQI)

    Fathi, P.; Ebrahimi, E.; Mirghafarry, M.; Esmaeili Ofogh, A.
    The Choghakhor International Wetland plays an important role in preserving and protection of part of the plant and animal species in the Iranian plateau. Since the water of this wetland is utilized for different human purposes, complete periodic chemical and physical quality assessment of its water seems necessary. Water quality index (WQI) was calculated using the following eleven parameters: Nitrate, Nitrite, Ammonium, Alkalinity, Hardness, Turbidity, Conductivity, Dissolved Oxygen, Total Dissolved Solid, pH and Biochemical Oxygen Demand (BOD5). For this purpose, the relative weight assigned to each parameter ranged from 1 to 4 based on the importance of the parameter for...

  10. Comparison of some blood parameters of rainbow trout (Oncorhynchus mykiss) living in running and still water

    Coşkun, O.F.; Aydın, D.; Duman, F.
    The aim of this study was to compare some biochemical blood parameters of rainbow trout (Oncorhynchus mykiss) living in running or still waters. Some biochemical parameters of rainbow trout were examined, and the results were evaluated between sampling locations and according to seasonal changes. Healthy adult rainbow trout were caught from six different locations on the Bahçelik Dam Lake and the Zamantı River (Turkey). Blood samples were collected from the caudal vena cava and transferred to sample tubes. The blood serum samples were analyzed for 16 different biochemical parameters. In terms of the calculated blood parameters, no statistically significant differences...

  11. Evaluation of effects of physico-chemical factors on chlorophyll-a in Shadegan International Wetland - Khouzestan Province - Iran

    Ghorbani, R.; Hosseini, S.A.; Hedayati, S.A.A.; Hashemi, S.A.R.; Abolhasani, M.H.
    Measurement of chlorophyll-a can be considered important to investigate the primary production of an ecosystem. This study aimed to investigate chlorophyll-a concentration, primary production and the factors affecting them in Shadegan Wetland located in Khouzestan Province - Iran. Sampling for measuring (NO3, PO4, BOD5, DO, pH, EC, salinity, temperature) was performed seasonally at five sampling stations of the wetland (Canal, Ragbeh, Khoroosi, Mahshahr and Atish), from March 2013 – through February 2014. Results showed that chlorophyll-a concentrations in Canal station were significantly higher than that in the other stations; however, there were no significant differences among the other sampling stations...

  12. Influence of trout farm effluents on water quality parameters and benthic macroinvertebrates

    Mesgaran Karimi, J.; Azari Takami, G.; Khara, H.; Abbaspour, R.
    The aim of this study was to assess the influence of trout farm effluents on water quality parameters in the Dohezar Stream. In this study two trout farms and 7 stations were selected and physiochemical of water, including air and water temperatures, dissolved oxygen concentration (DO), pH, electrical conductivity (EC), water flow and biochemical oxygen demand (BOD) were measured every 30 days for one year. A combined total of 60 benthic macroinvertebrate taxa were collected from the seven sites of the stream. The results showed that trout farms had a significant impact on EC, pH, water flow and BOD in...

  13. Relationships between the physicochemical parameters and zooplankton in Eğirdir Lake (Turkey)

    Apaydın Yağcı, M.; Yağcı, A.; Dölcü, B.
    The zooplankton community structure in Eğirdir Lake (Isparta-Turkey) was studied monthly throughout an annual cycle (January 2010-December 2010). The zooplankton community was represented by three main groups: Rotifera, Cladocera and Copepoda, respectively comprised 89.62%, 7.78% and 2.60% of the total zooplankton abundance. Eğirdir Lake was dominated by the rotifera Polyarthra dolichoptera in September and October, that succeeded by cladocera Bosmina longirostris species during December. Canonical correspondance analysis (CCA) was used to relate species distribution to environmental factors. The variation in the species data was significantly (p<0.05) related to a set of environmental variables (conductivity, carbonate, pH, ammonium, organic substances, dissolved...

  14. Effects of Spartina alterniflora invasion on distribution of Moerella iridescens in a tidal flat of western Pacific Ocean

    Ge, B.M.; Zhang, D.Z.; Tang, B.P.; Bao, Y.X.; Cui, J.; Hu, Z.Y.
    The invasion of Spartina alterniflora significantly affected the local ecosystem of Western Pacific Ocean where Moerella iridescens lives. Five patches with different invasion stages of S. alterniflora were selected and the influence on distribution of M. iridescens was studied on the coast of Wenzhou Bay, China in 2007. The aggregated distribution pattern was proved by using Taylor's power regression and Iwao's plot regression methods (p<0.001). The densities were significantly affected by the factors of S. alterniflora invasion stage and season (p<0.001), but no significant effect of interaction (p=0.805) occurred. M. iridescens mainly clumped in the habitats of no invasion and...

  15. Short communication: Using polychaetes as an assessment tool for health status of Jafari Creek, north-west of the Persian Gulf

    Mooraki, N.
    Marine ecosystems and their adjacent coastal habitats, especially estuaries are important because of maintaining the coastal biota, including a diverse array of organisms. However, these ecosystems are being impacted by the anthropogenic activities through urbanization and industrialization developments. For evaluating the degree of alteration occurring in these valuable ecosystems, scientists have conducted several methodologies based on chemical assays (i.e. directly measured abiotic parameters of the environment) and use of ecological indices. ... In this regard, the present paper was prepared to evaluate the health status of Jafari Creek using polychaetes as indicators and to compare the results with the previous...

  16. Climate change and the challenges of fisheries resources management in Nigeria

    Olokor, J.O.
    This paper takes a practical look at the challenges faced by fisheries resources in Nigeria due to climate change. It shows that Chad which produce 60% of smoked fish in Nigeria worth N2.6 billion is at the brink of extinction and is expected to dry to a mere 2000 sq km by year 2010 from over 25,000sq km in the 1960s. In simple clear terms, the paper gives practical adaptation and policy to face the challenges of climate change.

  17. Levels of heavy metals in sediments in the vicinity of Chabahar Bay desalination plant

    Miri, M.; Nabavi, S.M.B.; Doustshenas, B.; Safahieh, A.R.; Loghmani, M.
    Desalination plants are potentially capable of having impacts on coastal marine environments due to the production of wastewater with high concentrations of salts (brine discharge) and some heavy metals. The aim of this study was to examine the concentration of accumulated metals (Ni, Cu, Cd, Fe, Zn, Pb) in the sediments near the brine discharge point in the Chabahar Bay. Twenty one sediment samples were collected from seven stations in summer pre-monsoon and post-winter monsoon, in April and October 2011. The results showed that stations closer to brine discharge points had higher concentrations of metals in the sediment than other...

  18. Plankton communities of Ikpa River, South East Nigeria exposed to sand-dredging activities

    Ekwu, A.O.; Udo, N.D.
    Plankton communities of Ikpa River, downstream from a sand-dredging area were studied for a period of i2 months (March 2010 to Febntary 2011), covering dry and wet seasons. Most Physico-chemical parameters (pH, Turbidity, Silicates, Transparency and Conductivity) exhibited highly significant spatial variation (p<0.01), whereas seasonal variation of these variables was not statistically significant(p>0.05). Significant seasonal variation (p<0.05) was however observed in temperature, Dissolved Oxygen, Biochemical Dem and(BOD), total Dissolved Solids (TDS), Phosphorus, Nitrates and Conductivity. A total of 51 Taxa of Phytoplankton to 43 genera and 5 families were identified during the period of study. Bacillariophyceae recorded the highest relative...

  19. Caspian whitefish, Rutilus frisii kutum Kamensky, 1901 a potential aquaculture candidate: study on the cumulative effects of salinity and temperature on culture performance

    Ahmadian, E.; Malekzadeh Viayeh, R.; Zahmatkesh, A.
    In this study, growth and survival of the Caspian whitefish, Rutilus frisii kutum, (mean weight 0.59±0.06g) have been estimated at different rearing salinities (0, 5 and 10‰) and temperatures (24 and 28˚C). Maximum fish weight gain (493.65±14.07%) and specific growth rate (SGR) (2.74±0.15%), and minimum feed conversion ratio (FCR) (1.66±0.06) were obtained at salinity of 5‰ and temperature of 24˚C. There were significant differences in fish weight and length gain between the two rearing temperatures at salinity of 10‰ and between salinities of 0 and 5‰ at 24˚C (p<0.05). However, salinity and temperature did not significantly affect fish survival. Factorial...

  20. Changing trends in the abundance and biomass of cyanobacteria in the southern part of the Caspian Sea in 2009 (the stretch between Tonekabon and Amirabad)

    Mahdavi, M.; Maktabi, T.; Mahdavi, S.; Roostaie, M.; Alasvandi, M.F.
    Changes in abundance and biomass of cyanobacteria have been studied in the southern part of the Caspian Sea (the stretch between Tonekabon and Amirabad) in four seasons (spring, summer, autumn, winter) in which samples were taken from five depths of 5, 10, 20, 50 and 100 meters in the stations of Tonekabon, Noushahr, Babolsar and Amirabad. Samples were fixed in formalin (2-2.5%) before transferring to the lab for both qualitative and quantitative analyses. Ten species of cyanobacteria were identified with higher abundance and biomass in the euphotic layer compared to the aphotic layer. Temperature and nutrients have shown significant differences...

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