Showing 4 results for Persian Gulf and Oman Sea
Mehdi Gholamalifad, Bonyad Ahmadi, Parisa Nouri,
Volume 9, Issue 4 (11-2020)
Abstract
Primary production is a key indicator in the evalution of aquatic ecosystems that can directly affect carbon sequestration. Due to climate change and environmental dynamics, this component has changed spatially and temporally in different ecosystems. Therefore, to understand and monitor these changes, the most important influential parameters include; sea surface temperature, chlorophyll-a and algal bloom on this component and their changes were analyzed based on the time series. Images related to Chl-a, SST and NPP from January 2003 to December 2018 were used by MODIS sensor and VGPM model to estimate NPP in the study area. Aftar pre-processing and extracting the time series algorithm, the trend of variation was determined using the mann-kendall and theil-sen procedure. Then, using enhancing false color composite, algal blooms in the Persian Gulf and the sea of Oman were identified and the amount of chl-a concentration in the algal bloom area and outside the area was determined. The results of trend analysis with theil-sen procedure showed that the rate of change for chl-a is decreasing in all regions except the fifth region. The highest amount was observed in the fifth region (-0.19), which corresponded to the rate of NPP. The results also show that the highest amount of NPP in the first region in March and the lowest in June and July (540 and 690 gC/m2/day), which corresponds to the amount of chl-a concentration. Despite the apparent correlation, there is no cause-and-effect relationship between SST and chl-a as well as chl-a and NPP. In this way, factors other than chl-a can be considered for algal bloom and NPP.
Mohammad Seddiq Mortazavi, Seyedeh Laili Mohebbi Nozar, Sana Sharifian, Khosrow Aeinjamshid, Hadi Koohkan, Mohsen Mazravi,
Volume 13, Issue 1 (1-2024)
Abstract
In this study, a comprehensive assessment of the occurrence and spatial distribution of heavy metals including Nickel, Lead, Zinc, Copper, Cadmium and Chromium, as well as, TPHs in the surface sediments of the coastal areas and far from the coast of the Persian Gulf in Bushehr and Khuzestan provinces were performed to identify the possible sources of sediment contamination and determining the degree of pollution. Eight pollution indices were used to evaluate the quality of sediments in terms of heavy metal and TPH pollution. The investigated areas could be distinguished by a significant degree of heavy metal pollution of Nickel, Cadmium and Zinc. High concentrations of Nickel and Zinc were observed in stations around Nakhiloo, Bushehr. The comparison of average pollution indices between regions showed that both Bushehr and Khuzestan provinces, respectively, with the average of contamination degree (CD) (20.25 and 22.11), modified contamination degree (MCD) (3.38 and 3.69), pollution load index (PLI) (31.17 and 57.57), potential ecological risk index (PERI) (353.54 and 349.39) have a significant degree and risk of Nickel and Cadmium pollution, especially in Nakhiloo area, Bushehr. Investigating the spatial fluctuations of the concentration of TPHs in two provinces showed an increasing trend from Bushehr to Khuzestan. However, areas were located in no pollution or low pollution zonation and were safe from the adverse biological effects of TPHs. Comprehensive and impressive strategies to control and reduce these pollutions, especially in polluted areas, should be considered, so that the sources of these pollutions be managed.
Mohammad Darvishi,
Volume 13, Issue 3 (10-2024)
Abstract
Tuna fishes are one of the most important and commericial tuna species in Northern of the Persian Gulf and Oman Sea. The tuna fish stocks Thunnus tonggol was assessed in Hormuzgan coastal waters using software FiSAT . Data were collected minimum 200 fish per month simple randomly from five major traditional fish-landing sites in Hormuzgan Province, from November 2021 to September 2023. The monthly individuals ranging of T. tonggol from 21 - 108 cm fork length with mean 71.08 ± 1.23 cm.The infinity length and growth parameters (K, L∞) for T. tonggol, were computed 121.17 cm and 0.68 respectively. Growth performance index (Phi Monreo) calculated for T. tonggol , 8.9 which was in agreement with the finding of the other studies in the Indian Ocean. The results showed that this species has a high growth rate in the first 2 years of their life. The (a, b) parameters in power equation length-weight relationship for T. tonggol were (0.00002, 2.94), indicating that T. tonggol has isometric growth. Total mortality, natural mortality, fishing mortality rate and exploitation ratio (Z, M, F, E) were estimated for T. tonggol (2.89, 0.71, 2.18, 0.75). These results indicated that population of T. tonggol is overexploited and no scope for improving production in Hormuzgan Province. Tuna fish stock are trans boundaries and its fishery management and long term monitoring programs would be conducted in collaboration countries bordering the Persian Gulf, Oman Sea and Indian Ocean
Mohammad Seddiq Mortazavi, Leili Mohebbi-Nozar, Sana Sharifian, Sharareh Khodami, Ali Salarpoori, Hadi Koohkan, Gholamali Akbarzadeh,
Volume 13, Issue 4 (11-2024)
Abstract
The dramatic increase in heavy metals, their stable nature, and high toxicity, is gradually becoming a global crisis. In a recent study, a comprehensive assessment of the spatial distribution of heavy metals including Cd, Pb, Ni, Cu, Zn, and Cr was performed in industrial and commercial areas, including the sediments of 32 stations located in the area of Jask, Bandar Abbas, Qeshm, and Bandar Lange during the 2021to 2022. In this area, the concentration of heavy metals showed significant spatial variations between the areas. The maximum concentration of Cd was 0.55 μg/g in the first station of Gasheh. The second station of Khor Langeh had the highest Pb concentration with an average of 10.25 μg/g. The maximum concentration of Cr was 2420.33 μg/g in the second Shahid Bahonar station. The highest Zn concentration of 268.56 μg/g was observed in the first station of Suru beach. In the first station of Shahid Rajaei port, the highest concentration of Cu was observed at 18.36 μg/g. The maximum concentration of Ni was 519.02 μg/g in the second station of Shahid Bahonar.The stations located in Shahid Bahonar port, Suru beach, and Khor Gorsouzuan had a higher pollution intensity than other places and significant pollution risks, especially in terms of Cr, Ni, and Zn. In these areas, Cr was identified as the most dangerous metal. It is necessary to consider comprehensive strategies to control and reduce these heavy metal pollutions, to identify and manage the sources of these pollutions.
