فهرست مطالب

the Persian Gulf (Marine Science) - Volume:7 Issue:23, 2017
  • Volume:7 Issue:23, 2017
  • تاریخ انتشار: 1396/03/20
  • تعداد عناوین: 8
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  • Hassan Zare-Maivan *, F. Lotfifard, Zahra Tayebi Pages 1-12
    Moist and temperate Caspian forests are associated with a diversity of soil types and topography. Although, natural history and ecological attributes of the Caspian vegetation is well-documented, little is known about mycorrhizae of the Caspian (Hyrcanian) flora. Samples of herbaceous plant species were collected from 4 pre-determined altitudes (-13 upto about 1500m above sea level, approximately 500 m apart from three selected areas (Javaherdeh,J; Dalkhani,D; and Tonekabon,T) in Ooctober 2014. In addition, soil samples were collected from top 30 cm and analyzed for their physicochemical properties, mycorrhizal occurrence in roots and fungal spore density and diversity. Forty nine plant species from 30 families were sampled, identified and preserved. Brachypodium sylvaticum (Huds.) P. Beauv. and Polygonum mite Schrank. had the most frequent distribution in 4 and 6 of 11 stations, respectively. Results of this research revealed that plant species distribution in different forests varied in corresponding altitudes. However, within each forest, although plant species composition varied with increasing altitude and usually one species dominated in each forest, there were no clearcut ranges between habitats in altitudinal gradients studied here. AM fungal community composition, although unique to each rhizosphere, showed great variation between stations and amongst forests as was for the plant species. Results showed Shanon-Weaver diversity indiex for fungi generally followed the same pattern for plants. Pielou’s evenness indices of fungal species did not vary significantly, but differed within stations in each forest. There was no strong correlation between fungal density and soil elements as well as pH and EC except with contents of Na and clay at lower altitudes which correlated negatively with. We established the importance of mycorrhizal fungal community in development of understory herbaceous vegetation in Caspian forests, emphasizing the importance of elevation from sea level, sodium cation exchange capacity and soil texture in plant community development.
    Keywords: Caspian flora, Hyrcanian flora, AM fungi, Altitude
  • Parviz Bavarsad, Mani Arman, Bita Tangestani * Pages 13-24
    Moist and temperate Caspian forests are associated with a diversity of soil types and topography. Although, natural history and ecological attributes of the Caspian vegetation is well-documented, little is known about mycorrhizae of the Caspian (Hyrcanian) flora. Samples of herbaceous plant species were collected from 4 pre-determined altitudes (-13 upto about 1500m above sea level, approximately 500 m apart from three selected areas (Javaherdeh,J; Dalkhani,D; and Tonekabon,T) in Ooctober 2014. In addition, soil samples were collected from top 30 cm and analyzed for their physicochemical properties, mycorrhizal occurrence in roots and fungal spore density and diversity. Forty nine plant species from 30 families were sampled, identified and preserved. Brachypodium sylvaticum (Huds.) P. Beauv. and Polygonum mite Schrank. had the most frequent distribution in 4 and 6 of 11 stations, respectively. Results of this research revealed that plant species distribution in different forests varied in corresponding altitudes. However, within each forest, although plant species composition varied with increasing altitude and usually one species dominated in each forest, there were no clearcut ranges between habitats in altitudinal gradients studied here. AM fungal community composition, although unique to each rhizosphere, showed great variation between stations and amongst forests as was for the plant species. Results showed Shanon-Weaver diversity indiex for fungi generally followed the same pattern for plants. Pielou’s evenness indices of fungal species did not vary significantly, but differed within stations in each forest. There was no strong correlation between fungal density and soil elements as well as pH and EC except with contents of Na and clay at lower altitudes which correlated negatively with. We established the importance of mycorrhizal fungal community in development of understory herbaceous vegetation in Caspian forests, emphasizing the importance of elevation from sea level, sodium cation exchange capacity and soil texture in plant community development.
    Keywords: Cold Chain, Foreign Trade, Perishable Goods, Marine
  • Mehdi Mumipour * Pages 25-38
    Digital Elevation Models (DEMs) are used to estimate different morphologies, analysis of river profile, delineating drainage basin and drainage pattern associated with lithological and structural changes. The study area is Maroon River located in Khuzestan Province, Iran. In this study geomorphometric analysis based on DEM carried out to understand Maroon river uplift rate and tectonic- erosion relationships in its catchment. Geomorphic processes, such as stream length gradient, Hypsometric Integral, Isobase map, Incision map and concavity of the river were extracted from digital elevation model. Slope- Area plot was used for analysis of uplift rate and stream power of the river. Results show that the changes in stream length (SL) are because of lithological change in the study area. More erodible lithologies cause low SL values. Isobase map of the study area was obtained by relating drainage network and topographic surface. Isobase map delineate structural and lithological erosional processes. Hypsometric integral and hypsometric curve of the Maroon River catchment indicates a old catchment, so erosion is more effective in landscape evolution than tectonics. Uplift rate map of Maroon River shows different rates in upstream and downstream of the river. Concavity and Steepness indices were obtained using stream profile analysis and by using power function, uplift rate is calculated. Logarithmic regression of the area and slope values of the Maroon River lead to calculating concavity and steepness values. It is concluded form this investigation that erosional condition is more powerful in the study area.
    Keywords: Geomorphometric Analysis, Maroon River, DEM, Uplift Rate
  • Masoud Sadrinasab *, Mahboubeh Hosseinpour Pages 39-50
    Investigation of stratification in marine environments is always considered by researchers. In this study double-diffusive convection and stratification in the Bab el Mandeb strait is investigated by analyzing of field data. Measurement of seawater temperature and salinity from ARGO project (2009 to2014) and also R-V Knorr (2001) cruise with the daily average of seawater temperature and salinity at different levels of HYCOM㐣 (2001 to 2014) are used in this research. For a better understanding of the physical condition of the study area, seawater temperature, salinity, density, buoyancy frequency, density ratio and Turner angle changes versus depth are plotted and analyzed. The results illustrated that the depth of mixed layer is almost 100 meters during the winter monsoon and there is a stable stratified structure at this time of the year. Due to a thermohaline intrusion from the Red Sea, a temperature inversion is occurred, while below 150 meters the upper and lower boundary diffusive convection and a salt fingering established, respectively. In the northern part of the strait, the temperature inversion occurs below the depth of 200 meters. The double-diffusive convection is moderately weak in the northern part whereas, in the western part of the strait, it is mostly diffusive convection. Around 62.4% of the Bab el Mandeb strait exhibited favorable conditions for double diffusion processes during the winter monsoon; among that, ~4% was associated to salt fingering and ~96% to diffusive convection. Considering the fact that these conditions have been observed in different years, stable stratification and double-diffusive convection can be considered as a characteristic for the Bab el Mandeb strait during the winter monsoon.
    Keywords: Intrusion, Stratification, Double, Diffusive Convection, Turner angle, Bab, el, Mandeb Strait
  • Nasrin Hassanzadeh *, Samar Mortazavi Pages 51-60
    Cadmium (Cd) is one of the most toxic environmental heavy metals to organisms. The prominent toxic effects of Cd on reproductive organs are very well known. Gonad histopathology is a valuable tool for the assessment of endocrine disruption compounds EDCs effects on fish. The aim of this study was to evaluate the reproductive toxicity of cadmium chloride (CdCl2) on histopathology of Zebrafish (Danio rerio) testis under sub-lethal conditions. Male Zebrafish were exposed to four concentrations of CdCl2 (0.002,0.02, 2, and 20 mg/L) for 21 days in semi-static conditions. Histopathological changes in testis and Gonad Somatic Index (GSI) were studied. Treatment at 0.002 to 20 mg/L cadmium had no significant effect on the survival and condition factor. GSI decreased in a dose- dependent manner and the decrease was significant (P
    Keywords: CdCl2, Histopathology, Blood–Testis Barrier (BTB), Reproductive, Toxicity
  • Mahmood Sinaei * Pages 61-70
    In this study, heavy metals (Hg,Cd,Pb,Cu,Zn) and metallothionein (MT) biosynthesis were measured in blood of green sea turtles (Chelonia mydas) nesting on the northern coast of the Sea of Oman. Heavy metals concentrations in the sea water, the sediments, the blood samples ranged between 0.02-8.43 μg/l, 0.06-10.32 μg/l, and 0.16-36.78μg/g (ww), respectively.The highest concentration of heavy metals were measured at Ahmad rizeh followed by Ramin>Lipar >Kacho> and Tang Provinces. The concentrations of heavy metals in the coastal water and sediment were as follows; Zn>Cu>Pb>Cd>Hg. There were no significant differences between concentrations of heavy metals in different clutches laid in a nesting season. The lowest MT biosynthesis was recorded (115.7 ± 18. 12 μg/g dry weight) at the Tang sampling sites, while the highest was registered (276.4 ± 22.18 μg/g dry weight) at the Ahmadrizeh. The relationship between metallothionein biosynthesis and heavy metals in the blood samples, the sea water and the sediment were significant (p
    Keywords: Sea water, Sediments, Blood, Pollution, bioavailability, Chelonia mydas
  • Hamid Rezai *, Seid Ali Mohtarami, Hammed Dehghani, Parviz Tavakoli-Kolour, Hamid Reza Bargahi Pages 71-78
    Field studies were conducted in a number of intertidal and offshore islands in the Persian Gulf between 2006 to 2013. SCUBA and skin diving surveys were conducted around Larak, Hormuz, Qeshm, Hengam, Farur, Kish, Lavan, Khark and Farsi islands in the northern region of the Persian Gulf. Marine invertebrates including nudibranchs were photographed up to 32 m. Several species of nudibranchs are reported from the northern region of the Persian Gulf, over the Iranian side. In total, 32 genera of nudibranchs are recorded, which include Fryeria rüeppelii, Haminoea sp., Chromodoris annulata, Gymnodoris rubropapulosa, Cuthona yamasui, Hypselodoris maridadilus, Glossodoris pallida, Glossodoris sp., Asteronotus cespitosus, Marioniopsis viridescens, Stylocheilus striatus, Jorunna funebris and Elysia sp. were recorded from several Iranian Island in the Persian Gulf. The most common species was Chromodoris annulata throughout most of the surveyed islands, but Haminoea sp. was highly abundant and conspicuous species only in Farsi Island. Except for G. pallida, Glossodoris sp. and C. annulata, all the above species are considered new records for the northern region of the Persian Gulf, but Bursatella leachii, M. viridescens, Phestilla lugubris, Discodoris lilacina and Haminoea sp. are new records from the Persian Gulf proper. An increase in several new records to the Iranian fauna and new records of rare species, in relatively few years results mainly from sampling effort and contributions by specialists on samples of poorly known sampled areas. Prospects for finding new and more species are promising given more diving operations are carried out.
    Keywords: Nudibranchs, SCUBA, Underwater photography, Islands, Diversity, Persian Gulf
  • Maziar Khosravi *, Vahid Chegini, Seyed Mostafa Siadat Mosavi, Ross Vennell Pages 79-88
    Thirteen repetitions of a cross-channel transect in the Khuran Channel within the Strait of Hormuz allowed the description of the mean flow and semidiurnal tidal properties of a north-south transect. Water velocity profiles were obtained with a 614.4 kHz TRDI Work Horse Broadband ADCP along this 3.3 km long transect on 10 October 2014, the third day of secondary spring tide. The M2, M4 and M6 frequencies were separated from the observed current using sinusoidal least squares regression analysis. The semidiurnal tidal currents along this transect exhibited typical amplitudes of 160-170cm/s, decreasing toward coastal waters. The mean flow which confirmed the occurrence of asymmetry between ebb and flood phase of tidal current in Khuran Channel were ebb dominant in the deeper part of the channel and southern slopes and flood dominant over the shallower areas, with greatest magnitudes (10 cm/s) near the surface mainly in the deeper parts of the northern side of the channel. The tidal current amplitudes decreased and for the most with depth and followed the bathymetry particularly in the middle of channel, which reveals the dominants of frictional forces. The large overtide amplitude is as a result of nonlinearities that were produced by increased frictional effects that lead to the asymmetry between ebb and flood phase of tidal current in this channel.
    Keywords: Khuran Channel, Strait of Hormuz, Tidal Currents, Persian Gulf