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 = Earth Sciences

Mostrando recursos 1 - 8 de 8

  1. Short communication: Ecological classification of southern zones of the Caspian Sea (Mazandaran Province), based on CMECS model

    Hoseinzadeh, M.A.; Owfi, F.; Gorjian Arabi, M.H.; Keshavarz, M.
    A coastal area is a confluence of land and marine ecosystems and includes the independent biological, ecological, and geological area. Increasing pressure on these areas can decrease the quality of marine habitats, and can even lead to the loss of sensitive habitats. In this regard, a “biotope” has been suggested as the most informative operational unit for research and management. These biotopes, however, have been specified by the dominant species; they depend on the seabed, they are stable, and sometimes are used synonymously with the word ecology. Habitat classifications are, therefore, most accurate and ecologically relevant at the biotope level...

  2. Evolutionary study on two closed Gammarus (Crustacea, Amphipoda) species from Zagros Mountains (Iran) using molecular methods

    Azin Fahim, A.; Rezvani Gilkalaie, S.
    Mitochondrial Cytochrome Oxidase Subunit I DNA sequences are a good discriminative marker for phylogenetic studies in crustaceans and especially in amphipoda. In the present study, molecular and morphological data were analyzed to test whether Gammarus lobifer authority and Gammarus balutchi authority which [sic] one or two geographically separated but morphologically similar species. The analyses proved that there are two species and that uplift of the Zagros Mountains was probably the most important cause of Allopatric speciation in this region during the Miocene period.

  3. Ecological classification of southern intertidal zones of Qeshm Island, based on CMECS model

    Ansari, Z.; Seyfabadi, J.; Owfi, F.; Rahimi, M.; Allee, R.
    The “Coastal and Marine Ecological Classification Standard (CMECS)”, a new approach to ecological classification, was applied to 122 km of the southern intertidal zone of Qeshm Island located the Hormouz Strait - the Persian Gulf. Two components of this model, Surface Geology (SGC) and Biotic Cover (BCC) were used. Considering the extent and geomorphological alternations of the covered area, 12 sampling sites within 5 sub-regions were designated using by GPS. In total, 60 habitats (biotopes) with 47 codes were determined; this variety of biotopes is directly related to the diverse surface geology (substrate) of the covered area. Most of the...

  4. Advanced oxidation processes against alkyl phenols in groundwater samples

    Zaribafan, A.; Baharlouie Yancheshmeh, M.; Fathi, T.; Ahmadkhani, R.; Haghbeen, K.
    Spectrophotometric examinations showed the presence of phenolic compounds in the organic residue collected from four groundwater resources located in vicinity of an oil refinery at the outskirt of Tehran. The average concentration of total phenolic compounds was about 0.38 mg.L-1 in these samples using Folin-Ciocalteu method. GC-Mass analysis disclosed that alkylphenols were the major phenolic contaminants in the samples. Evaluation of the Advanced Oxidation Processes (AOPs) efficacy for removal of alkylphenols from real water samples is a hot topic of recent Environmental Research due to the decomposition of these compounds in soil and by microorganisms which may results in the...

  5. Streamflow droughts assessment in Kurdistan Province, Iran

    Kazemzadeh, M.; Malekian, A.
    In this paper, we analyzed the streamflow droughts based on the Percent of Normal Index (PNI) and clustering approaches in the Kurdistan Province, Iran, over the 1981-2010. The Kolmogorov-Smirnov (K-S) test was considered for streamflow time series and the results of K-S test indicated that streamflow time series did follow the normal distribution at the 0.05 significance level. Generally, the results showed that mostly streamflow droughts have been commenced since 1997 and also in most of the stations the extreme streamflow droughts occurred in 1997-2001. Furthermore, the number of drought events in each station showed that the extreme streamflow drought...

  6. Sediment quality of lower reaches of Okpoka Creek, Niger Delta, Nigeria

    Davies, O.A.
    The sediment is the ultimate sink of contaminants in the aquatic systems. The physico-chemical quality of sediments lower reaches of Okpoka Creek was assessed for two years (wet and dry lsons).Sediment samples were collected at low and high tides from three stations according to standard methods. These were analysed for sediment particle size (sand, silt and clay), pH, total hydrocarbon (THC), total organic matter (TOM), total organic carbon (TOC) and conductivity. Analysis of variance (ANOVA), Duncan multiple range (DMR) and Pearson correlation cofficient were used to analyse the data. The sediment consisted of sand (57.86 ~c2.65%); silt 17.47~c1.68%) and clay...

  7. Some soil nutrient composition favouring the growth of Typha grass in Kebbi and Katsina States, Nigeria

    Birnin-Yauri, Y.A.; Daddy, F.; Kolndadacha, O.D.; Owotunse, S.
    This study was carried out by surveying all the water bodies of two states where Typha grass exists. Soil auger was used to take soil samples randomly from five different locations in both Kebbi and Katsina state at the depths of 0-5cm, 510cm, 10 15cm. Soil nutrient was analyzed for the mineral composition of the two States at different season and soil depths. The result showed that, soil depth between 5-10cm has the highest percentage of nitrogen, phosphorus, calcium and magnesium during dry season. The nutrient composition of soil from the two states followed the same pattern during wet season.

  8. Impact of Atlantic salmon cage culture on sediment chemistry in Mjoifjordur, Iceland

    Shakouri, M.; Auðunsson, G.A.
    Impact of Atlantic salmon (Salmo salar) cage culture in Mjoifjordur, Eastern Iceland on the chemistry of the sediment was investigated. Sediment samples were collected using a Shipek grab in December 2003. A core sub-sample was taken from each grab for analyzing total organic matter, total organic carbon, total nitrogen and phosphorus in different depths from three stations at various distances from the cage. These parameters were analyzed in the top layer of additional four stations. The results showed significant increase in all analyzed parameters in station 1, at 5m from the cage (p<0.05). The difference between reference station (600 m...

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