Recursos de colección

Aquatic Commons (38.811 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 = Limnology

Mostrando recursos 1 - 6 de 6

  1. Analysis of physicochemical characteristics of some freshwater bodies in Essien Udim Local Government Area of Akwa Ibom State, Nigeria

    Unanam, A.E.; Akpan, A.W.
    The physical and chemical characteristics of freshwater bodies Ikot Ebak and Abeneyentem streams in Essien Udim Local Government Area, Akwa Ibom State, Nigeria were studied from (July December 1996). The mean values obtained in the two water bodies were pH (6.8~c0.12, 6.8~c0.09, respectively). Conductivity (4.9~c2.26, 5.0~c2.09 iScm-1), total dissolved solid (16~c7.58, 37~c26.9 mg/l), TSS (46~c26.0, 53~c53.1)g/l), alkalinity (17.5~c7.27, 10.7~c8S MgCaCo3/1), DO (6.98~C1.46, 8.3~C29.0mg/1), BOD (2.65~c2.44, 3.15~c2.79mg/1), Salinity (0.41~c0.12, 0.31~c0.04%o') total hardness (0.64~c0.21, 0.84~c0.42mg/l, N03-N (0.31~cO.26, 0.35~c0.29mg/l), and PD4-P (0.022~c0.0199 0.023~c.022mg/1), respectively. There were significant difference in the means of the parameters in the two water bodies except TDS, Alkalinity and...

  2. Effect of water hyacinth (Eichhornia crassippes) infestation on zooplankton populations in Awba Reservoir, Ibadan, south-west Nigeria

    Uka, U.N; Chukwuka, K.S.; Daddy, F.
    The effect of water hyacinth infestation on the abundance, distribution and species composition of zooplankton in Awba Reservoir were investigated. Samples were collected in each of the sampling areas (water hyacinth infested and open water) by vertical zooplankton hauls using §1Yro bolting silk net. The species composition of the zooplankton from the sampled areas consisted of 3 taxa, comprising of 6 species of Cladocera (Moina sp.,Ceriodaphnia sp.,Pleuroxus sp.,Diaphanosoma sp.,Chydorus sp., and Leydigia sp.,) 6 species of Rotifers(Asplanchna sp.,Trichocerca.,Filinia sp., Polyarthra sp.,Brachionus sp.,and Lecane sp.) and 3 species of Copepoda(Cycloid copepods, Copepodite nauphii and Calanoid copepods). However, the study showed that the Rotifers had higher numerical abundance in the...

  3. Condition of pH and ionic composition of water in a macrophyte dominated reservoir (Hanna Reservoir - Isfahan Province), Iran

    Esteki, A.A.
    2/3 of the reservoir surface area was approximately covered with dense populations of Myriophyllum, Ceratophyllum and Potamogeton species. The headwaters of the reservoir were considered as hard water and had both carbonatic and non-carbonatic hardness. When they were exposed to lentic condition of the reservoir and its intensive photosynthetic activities of macrophyte communities, the bicarbonate ions were absorbed significantly and the pH of water increased to relatively serious levels and calcium carbonate precipitated as subsequontly. These processes caused a significant decrease in calcium and bicarbonate ion concentrations of the water column of the reservoir. Thus, in the headwaters, calcium and...

  4. Measurement the extract content of chlorophyll pigment (a,b,c) and correlations hydrologic parameters in summer (Case Study: Gomishan International Wetland)

    Omrani, S.
    Concentration of chlorophyll-a is an adequate parameter for assessing the trophic state in the summer. So, check the photosynthetic content of pigments as a bioindicator of chlorophylla,b,c were studied in six stations of Gomishan international wetland and a sea station. Furthermore were investigated the qualitative evaluation of trophic state of the wetland and its dynamics. Phytoplankton samples after the filtration were extracted in 90% acetone, and were obtained the absorption of pigments in Spectrophotometer. In addition to chlorophyll, were measured the water temperature, dissolved oxygen, pH, salinity, turbidity and depth. Based on results, the increasing concentrations of chlorophyll-a in September...

  5. Water quality assessment of the Zayandehroud Lake using WQI index

    Khalaji, M.; Ebrahimi, E.; Hashemenejad, H.; Motaghe, E.; Asadola, S.
    Biological and ecological studies of water resources play an important role in both researches and scientific studies. The most important step for this study is identifying the characteristics of the ecosystem, living organisms and environmental factors. In recent years, Water quality evaluation, especially drinkable water, became both important and essential for reduction in quality and quantity of them. Lakes and ponds always being under attention as the most important resources for drinking and agricultural purposes. To improve efficiency of uses of the water resources, we need appropriate methods to determine quality of them. Investigate the quality of the Zayandeh roud...

  6. Evaluation of coliform bacteria and nematode eggs in Haraz River runoff

    Yaghoubzadeh, Z.; Safari, R.
    Haraz River is an important river in north of Iran. This river is one of the vital importances in Mazandaran province and cities of Amol, Babol, Fereidoon'kenar and Nour. This river is considered the largest and most beautiful tourist destinations of Mazandaran because it has the path and landscape of the mountainous and forest. This study was conducted for survey the coliforms and nematode eggs in runoff of Haraz River. Forty eight samples from four stations were taken during a year and samples examined for total coliform, fecal coliform and nematode eggs. The results showed that maximum and minimum of...

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