Marine Environment
Mostafa Bahrebar; Mohammad Mansour Tootooni; Mehran Loghmani
Abstract
Introduction: Chitons are marine molluscs, mostly grazers, resistant to tidal conditions and often living in crevices of rocks. The Oman Sea is located in the southeast of Iran and the northwest of the Indian Ocean and is heavily influenced by the monsoon winds of the Indian Ocean. Due to the occurrence ...
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Introduction: Chitons are marine molluscs, mostly grazers, resistant to tidal conditions and often living in crevices of rocks. The Oman Sea is located in the southeast of Iran and the northwest of the Indian Ocean and is heavily influenced by the monsoon winds of the Indian Ocean. Due to the occurrence of the monsoon process, the Makoran Sea has a rich variety of marine species, including molluscs. The aim of the present research was to investigate the density and distribution of Acanthopleura vaillantii in the beaches of Pozm, Konarak, Tis, Kolbe Ghawasi, Darya Bozorg and Ramin in winter 2018 and summer 2019.Materials and Methods: In this study, the density and distribution of A. vaillantii was investigated in transects perpendicular to the sea and in the tidal zone, using a quadrat (1*1 m2). in the tidal zone of six stations on the coasts of Pozm, Konarak, Tis, Kolbe Ghavasi, Darya Bozorg and Ramin. A number of samples in each station were taken to the laboratory to measure biological parameters such as length, total wet weight, soft tissue moisture content, tissue moisture percentage and dry weight percentage. In each station, physical and chemical factors of water (temperature-salinity and acidity) were measured and recorded by WTW device. Results: Investigations showed that the highest average density in the winter of 2018 was in Ramin station and was equal to 11.27 ± 1.46 m2. In total, Ramin station had the highest average density in winter and summer with a value of 19.15 ± 2.67 m2. Also, the lowest average density was related to the diving hut station in summer and the first transect of the lower part of the tide, which was not recorded due to the presence of a sandy bed. In total, the average density for two seasons was 0.85 ± 0.26 m2 at the Kolbeh ghavasi station. Also, the statistical test showed a significant difference between the stations (P<0.05). The biological parameters showed that in Tis station, in winter and summer respectively, the maximum average length was 53.56±4.25 and 58.2±4.53 mm, weight was 23.19±7.43 and 22.8±51. 28.28 grams and at the Kolbeh ghavasi station for winter, the lowest average length was 32 ± 2.14 mm and weight was 2.99 ± 0.85 grams. In the Big Darya station, for summer, the lowest average length and weight were 43.44 ± 4.21 mm and 16.53 ± 4.89 grams, respectively. Discussion: According to the results of other researchers, Tis station has high biodiversity, but the results of the present study showed that in this station, A. vaillantii samples had more weight and length despite the lower density (probably due to competition). Also, there was more density and distribution in the crevices of rocks and tidal pools with algal cover and temperature of 22 to 26 degrees Celsius.
Marine Environment
Mahshid Jalili; Abolfazl Saleh; Maryam Fallahi; Ali Mashinchian Moradi; Mohammad Reza Fatemi
Abstract
The abundance, distribution, biodiversity and species composition of phytoplankton and the concentration of nutrient were evaluated in Chabahar Bay during 2018-2019. Phytoplankton succession is mostly posh by physical factors, nutrient availability, mixotrophy and phytoplankton’s predators. Water ...
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The abundance, distribution, biodiversity and species composition of phytoplankton and the concentration of nutrient were evaluated in Chabahar Bay during 2018-2019. Phytoplankton succession is mostly posh by physical factors, nutrient availability, mixotrophy and phytoplankton’s predators. Water sampling was carried out by Niskin water sampler from 9 stations in 6 time periods (pre-monsoon, 2 times in southwest monsoon, post-monsoon and 2 times in summer monsoon). The physical and chemical factors were also recorded. In this study, 114 phytoplankton genus and species belonging to 4 main taxa were identified, of which the most dominant phytoplankton was Dinophyta with abundance of 94%. A significant difference of the density of phytoplankton among sampling months was observed (non-parametric Kruskal-Wallis analysis, p≤0.05). Clear paradox between phytoplankton abundance and nutrient concentration was detected. The results showed that increasing the concentration of nutrients by the autumn resulted in highest number of phytoplankton in winter. CCA Analysis explained about 84% of variations on the phytoplankton density cause by nutrient concentration and dissolved Oxygen.
Marine Environment
Hamidreza Akbarpoor; Bagher Mirabbassi; Ehsan Kamrani
Abstract
Marine pollution has long been cited as one of the priorities and high-level goals of the International Maritime Organization (IMO), with marine pollution by dumping of wastes being considered one of the most important issues raised by IMO. The present study seeks to study the performance of IMO as the ...
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Marine pollution has long been cited as one of the priorities and high-level goals of the International Maritime Organization (IMO), with marine pollution by dumping of wastes being considered one of the most important issues raised by IMO. The present study seeks to study the performance of IMO as the authority in charge. Overall, IMO has paved the ground for tackling different types of marine pollution through changing its structure and bringing it in line with the objectives stipulated in its statute. The establishment of the Marine Environment Protection Committee and the subsequent formation of the Sub-Committee on Pollution Prevention and Response clearly demonstrate IMO's special emphasis on combating different types of pollution, particularly pollution by dumping of wastes. In addition, drafting and ratifying the special Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention) and its Protocol has greatly helped concentrate efforts aimed at fighting this type of pollution. The Convention and its Protocol govern waste disposal control through implementing supervisory programs. Moreover, the Convention initially targeted disposal of a certain type of waste and further narrowed the scope of the regime gradually, which led to further protection of the marine environment and marine interests, including marine economic interests. Overall, the London Convention and its protocol have made waste disposal pollution the focus of the maritime community and provided appropriate legal tools to control and prevent this type of pollution.