جستجوی مقالات مرتبط با کلیدواژه « Monsoon » در نشریات گروه « زیست شناسی »

Gastropods are integral members of benthic communities, playing pivotal roles in the energy dynamics of aquatic ecosystems. This research aimed to assess changes in gastropod density influenced by seasonal variations and environmental parameters. The study was conducted during winter (pre-monsoon) and autumn (post-monsoon) periods across three areas (Khor Bahu, Khor Gowatr, and Gowatr Bay), spanning nine stations within Gowatr Wetland. Sampling of the sub-island media stations was performed using a van-veen grab. Analysis of temperature, salinity, pH, total organic matter (TOM), and granulation was conducted. Results revealed notable fluctuations in gastropod density across seasons and locations. During winter, the highest densities were observed in Khor Bahu (Pyramidellidae with 945 ± 29.15 individuals/square meter), Khor Gowatr (Marginellidae with 745 ± 36.15 individuals/square meter), and Gowatr Bay (Naticidae with 248 ± 28.14 individuals/square meter). In contrast, during autumn, peak densities were recorded in Bahu estuary (Nacellidae with 775 ± 38.45 individuals/square meter), Restusidae estuary, and Gowatr Bay (Eulimidae with 235 ± 26.12 individuals/square meter). Significant differences in density were observed among stations (p<0.05), while no significant variation was noted between seasons (p>0.05). Correlation analysis revealed a significant association between density and grain size (R=0.64), highlighting its influence on gastropod abundance. Despite the lack of significant seasonal density differences, the autumn season exhibited increased gastropod abundance, possibly attributed to the impact of southwest India's summer monsoon winds

Among the many biochemical biomarkers used to assess contamination of the marine environment, metallothionein protein is considered as one of the very important and useful tool inrelated to biochemical markers metals. The aim of this study was to evaluate Metallothionein changes in natural condition in polychaete Glycinde bonhourei of 9 stations Chabahar Bay sub-tidal area from 2014 to 2015 with consideration before the monsoon season, monsoon, post-monsoon and concentrations of copper, zinc ,cadmium in the polychaete tissue. Total average concentrations of copper and zinc and cadmium respectively recorded in the monsoon 6.39±2.04, 20.95±4.51, 0.136±0.04 micrograms per gram dry weight of the monsoon season 3.51±1.46, 11.84±2.65, 0.059 ± 0.01 and in the post-Monsoon 4.98 ±1.44, 16.51±3.58, 0.152±0.01 microgram per gram of dry weight that one-way analysis of variance showed significant difference between the station and seasons (p

In addition to heavy metals, environmental factors affect to induce the synthesis of metallothionein (MT) contamination biomarker in vertebrates and invertebrates. Environmental parameters that were selected of nine stations in Chabahar Bay subtidal area (2013-14)  include temperature, salinity, dissolved oxygen and turbidity and heavy metals (copper, zinc, cadmium) in monsoon and post-monsoon, pre-monsoon, that studied relation them with polychaete metallothionein concentration. Total mean of MT was recorded in pre-monsoon 28.3±5.2, monsoon 15.50±4.9, and post-monsoon 21.39±4.37 µg/ g and ANOVA test showed significant differences among stations and seasons (p≤0.05). There were no significant correlation between metal concentrations in sediments and tissue in stations and seasons, also between metals and MT. Except for temperature and salinity were increased in monsoon, MT and other parameters showed a significant decrease in this season. In PCA test, three components of variance revealed a total of 75.24 variance percent that the second component with 28.73 variance percent was included oxygen and transparency and MT. Despite significant changes of MT and environmental factors in different seasons and also had not been recorded correlation of MT induction with metals, as the main factors in the induction, emphasis the role of Chabahar Bay environmental parameters on biomarker fluctuations. Among the factors under the PCA, dissolved oxygen of the main factors is effective in reducing the synthesis of MT in G.bonhourei.

For study on effect of some environmental factors such as bottom structure, depth, dissolved oxygen on density and diversity of bivalves in the Iranian coasts of Gulf of Oman ( Hormoz strait – Gwatr Bay ) 10 stations were selected. A 0.1 m2 Van-Veen grab sampler was used for collecting sediments in addition to the physical and chemical parameters such as temperature, salinity, dissolved oxygen and pH using the CTD device. 95% Ethanol and Rosebengal were used for fixing and staining. In this study, 43 genera of 19 families of bivalves were identified. Lucinidae (55%), Nuculidae (13%), Tellinidae (7%), Veneridae (5%) and Yoldiidae (5%) were dominant groups. Pearson analysis results showed correlation among bivalves abundance and pH , dissolved oxygen and silt ( P

The aim of this paper was to study monsoon effects on polychaetes population structure in subtidal area based on some biodiversity indices. Sediments sampling was carried out by grab van-veen from 12 subtidal stations in three time periods (pre-monsoon, monsoon and post-monsoon). The physical and chemical parameters were also recorded. Mean density of polychaetes were recorded 1101.2 ±614.3 ind/m2 (pre-monsoon), 428.9 ±316.2 ind/m2 (monsoon) and 588.8 ±313.3 ind/m2 (post-monsoon). Shanon diversity indices were 2.08, 1.63, 1.83 respectively. The Hill indices was reversed and showed highest number in monsoon season and minimum number in pre-monsoon. These results represented non-uniform polycheates distribution during pre-monsoon. Cluster analysis of each season showed that deep stations were in separate disturbances. During the summer monsoon, variations in environmental factors and bottom distractions affected the density and diversity of polychaetes and as a stressor reduced the diversity and density during the monsoon.

Gulf of Oman, in the summer, is influenced by the southwest monsoon winds of India, and Jask protected area, which is ecologically and economically very important, is located in the northwestern area of this gulf. In this study, sampling of sediments was done from 2009 to 2010, in three station (mouth, mid and end) of Markazi creek (located in Jask city), by 0.04 m2 Van Veen Grab. Water physicochemical parameters (including dissolved oxygen, salinity, temperature and pH) of the water near the seabed, as well as sediments grain size, and total organic matter (TOM), were measured at each station. The relationships between diversity and abundance of macrobenthos and biological and non-biological factors, were studied in sampling seasons (premonsoon, monsoon and postmonsoon). A total of 14425 pcs per m2, belonging to 64 species of macrobenthos were counted and identified. In total, Gastropoda with 22 species and Bivalves with a frequency of 9125 pcs per m2, had the highest diversity and density of macrobenthos, respectively. The results of this study showed that, the spatial and temporal variation of macrobenthos in this area affected by climatic fluctuations are due to the Indian Ocean monsoon. The maximum and minimum densities of macrobenthos were identified at postmonsoon season (8075 pcs per m2, equivalent to 58.24% of total species), and during monsoon season (2766 pcs per m2, equivalent to 17.21% of total species), respectively. Results of calculating the diversity index, Shannon-Wiener, showed that the maximum and minimum value of this index were observed at premonsoon, end station (1.03), and postmonsoon, mid station (0.41), respectively.

This study was carried out in three inter tidal zones in the Iranian coast of Gulf of Oman, in 2010 to identify the species belonging to Family Ocypodidae and to investigate effect of monsoon on ecology of crabs. Two species of genus Uca (U. sindensis and U. iranica) from Jask and Khour-Khalasi study area and one species of genus Ocypode (O. rotundata) from Vanak beach were identified. The results were used to verify previous reports on species identification. Monsoon was found to affect distribution and frequency of these crabs. The maximum and minimum relative density were observed in pre-monsoon (May, 9.33 individual/m2) and monsoon (September, 6.38 individual/m2), respectively. Dense distribution of Uca was found in the muddy beaches of Khour-Khalasi and the genus Ocipode in the sandy beaches of Vanak area.