Cysts produced by dinoflagellates act as the seeds involved in the initiation of algal bloom through blooming and at the end of bloom through the reformation of cysts. Therefore, they are of great importance in environmental studies. In this study, sampling of sediments in the Gwater Bay, located on Iran's southeast coast and the northeast of the Oman Sea, was done in the spring (pre-monsoon) and summer (post-monsoon) of 2013 to examine the distribution and abundance of dinoflagellate cysts. Twenty-four species belonging to 12 genera of the dinoflagellate cysts were identified for the first time in this area. The results of ANOVA indicated no significant difference between the abundance of cysts in different seasons. A study of the Shannon index in this area revealed a high diversity and abundance in the study area. In this study, 8 species of dinoflagellate were found as potentially toxic species.

Ticks are important ectoparasites in equids which causes economic losses in animal husbandry of Iran and worldwide. This study was aimed to determine frequency and species diversity of hard ticks in equids in Turkman sahra, Iran. 240 equids were randomly selected and examined from 2018-2019. Ixodid ticks were collected from body surface of examined animals and identified. Of all examined equids, 37.91% horses, and 4.16% donkeys were infested with a total number of 357 ixodid ticks. Tick indices (tick number per animal) were 3.53.  The highest prevalence of hard ticks was found in ≥3 years-old equids in the region. There was significant difference between prevalence and different age groups of infested animals. Of all examined ticks (357), three genera including Hyalomma spp., Rhipicephalus spp. and Dermacentor spp. with four species. i.e. Hyalomma anatolicum (65.26%), H. marginatum (10.64%), Rhipicephalus bursa (22.12%) and Dermacentor marginatus (1.96%) were identified. Ixodid ticks’ infestations occured throughout the year with the highest prevalence in spring. There was significant difference between prevalence of hard ticks and seasons in this study. The results revealed that species diversity and ixodid ticks’ infestations were prevalent in the equids of Turkman sahra, Iran.

BACKGROUND AND OBJECTIVES: This study aimed to investigate the long-term relationship between chlorophyll-a, sea surface temperature, and sea surface salinity monthly from January 2015 to December 2021. It was carried out in the Northern Bay of Bengal, which experiences extreme monsoons, in the southwest monsoon and northeast monsoon from June to September and November to February, respectively. Monsoon is the main cause of changes in chlorophyll-a, sea surface temperature and sea surface salinity. METHODS: The seasonal model was used to examine the relationship between these three parameters, which were obtained using the Copernicus Marine Environment Monitoring Service data. The seasonal model was used to observe periodic patterns and predict parameters based on their regularity. Meanwhile, Pearson’, s correlation analysis was conducted to determine the relationship between chlorophyll-a, sea surface temperature and sea surface salinity. FINDINGS: This study found that the three parameters, namely chlorophyll-a, sea surface temperature, and sea surface salinity, follow the monsoon pattern, as shown in the seasonal model. The minimum value of chlorophyll-a occurred in February, March and April, while the maximum value of approximately 2 milligram per cubic meter occured at stations 1, 2, 3, 4, 5 and 7, but at 9 and 10, it increased to 12-14 mg/m3. This indicates that station positions are very sensitive to changes in chlorohophyll-a values. When the southwest monsoon occurred, it reached the maximum. Furthermore, the minimum sea surface temperature values occurred in January and at almost every station in the year. It was shown to be associated with the northeast monsoon, which causes winter. On the sea surface temperature graph, several peaks were observed in positive local extremes yearly at almost all stations. The maximum sea surface temperature occurred in May, June, and July, according to the shape of the graph, which peaked in the middle of the year. The sea surface salinity graph formed a peak and valley which occurred yearly in May or April, as well as September and October, respectively. CONCLUSION: Chlorophyll-a had 1 trough and 1 peak, with the sea surface temperature graph possessing only 1 peak, while the sea surface salinity graph had 1 peak and 1 trough, respectively. These graph patterns implied that chlorophyll-a first achieved a minimum value before reaching the má, ximum. The sea surface temperature graph had a maximum value in the middle of the year, while the minimum occurred at the beginning or end. Moreover, the sea surface salinity graph first reached the maximum value and then declined to the minimum.

The objective of the paper is to present the dependence of the wind profile of a monsoon on the depth of the layer, the ground surface roughness length, and the atmospheric stability. The paper also indicates that the wind profiles of the typhoon are composed of two layers, the upper one with the nearly constant velocity and the lower one in which the velocity decreases with the decrease in the height. The typhoon wind profiles are not stationary but changes abruptly.

At present, there isn't a clear and generally accepted definition for the term "Monsoon". Parameters used for studying monsoon are also quite different. S1fmmer monsoon affects east part of Afghanistan. In spite of climatic variety and wide mountainous area, network of meteorological stations of Afghanistan often lacks sufficient and long-term data. Monsoon circulation is originated by formation of thermal lows after June until September. The lows of L1 and L2 in Pakistan and Afghanistan are representatives of Intertropical Front (ITF). Within the low of L1 exists shallow maritime airmass, but there is warm continental airmass in L2. In most parts of Pakistan monsoon rainfall includes nearly 50% of total precipitation, whereas in Afghanistan monsoon rainfall is short and limited to eastern part of the country. Afghanistan monsoon rainfall falls into isolated storms with great time intervals. The monsoon circulation should be set before its first low reaches the country. The first stage of monsoon starts the second half of May until the beginning of June and its peak period is established when the first low reaches in early June and the last storms in August and September. It is expected that westward penetration of maritime airmass over Afghanistan in advancing periods of monsoon occurs in upper levels. Conditions of monsoon in Afghanistan are nearly similar to West Africa regions and furthermore it is complicated by Hindu Kush Range. Last limit of monsoon penetration reaches around north and northwest vallyes of Kabul, and Hindu Kush blocks its further penetration to west. One of the monsoon's features is periodic and non-periodic displacement of ITF. Its reason sets in consecutive displacing of continental airmass with maritime one and vice Versa. Another interesting feature of monsoon is its breaks. This phenomenon is established by temporal retreat or chang of monsoon airmass stratification due to penetration of midlatitude troughs to south and subtropical regions.

Monsoon is a very important meteorological phenomenon that affects a large part of the Indian Ocean every year. These effects sometimes extend to the seas and bays connected to this ocean, especially the Gulf of Oman, and have destructive effects on the economic activities of this area. Although the effects of monsoon on the coasts of Iran are much less than the coasts of the Arabian Sea, but local reports indicate that the monsoon usually affects two bays belonging to Iran, Chabahar Bay and sometimes Pazm Bay in the northeast of the Gulf of Oman. In this research, the monsoon phenomenon in the northwest of the Indian Ocean has been analyzed in order to investigate its effects on the waters of the Gulf of Oman. One of the important results of this study is the extraction of Monsoon Line. In this study, the monsoon line is defined as the boundary line of the monsoon. This line, if we call it the Monsoon line, indirectly connects Ras Al-Had to the west of Chabahar Bay and sometimes also includes Pazm Bay.

The aim of this study was to compare the accumulation of heavy metals copper, zinc and cadmium and to investigate the changes of metallothionein as a biomarker of contamination in the gill tissue of the ghost crab Ocypode saratan in the two time periods before Monsoon (May) and after Monsoon (November) in mongrove forests. Chabahar and Gwater Bay was done in 2019. The results of the study showed that in both pre-Monsoon and post-Monsoon seasons the pattern of metal accumulation in the gill tissue of the ghost crab is zinc> copper> cadmium. The mean concentrations of copper, zinc and cadmium were obtained in the pre-monsoon and post-monsoon seasons at Chabahar station, 173. 6 ± 3. 83, 186. 43 ± 3. 1, 0. 095 ± 0. 008, respectively and 156. 7± 4. 15، 175. 13 ± 2. 8, 0. 026 ± 0. 003 and in Gwater station the average concentrations of copper, zinc, cadmium in the two pre-Monsoon and post-Monsoon seasons were respectively 237. 03 ± 6. 4, 231. 8 ± 1. 8, 0. 048 ± 0. 003 and 205. 9 ± 6. 34, 253. 2 ± 2. 13, 0. 037 ± 0. 015 μ g/g dry weight. The mean levels of metallothionein in pre-monsoon and post-monsoon season in Chabahar station were 2. 02 ± 0. 01 and 0. 1 ± 0. 06, respectively, and in goiter station were 2 ± 0. 02 and 0. 12 ± 0. 02, respectively. Comparison of metallothionein levels between Chabahar and Gwater stations was not significant (P<0. 05). But in both stations separately between the two pre-Monsoon and post-Monsoon seasons, there was a significant difference (P<0. 05). Correlation between metallothionein and metals showed that there was no correlation between metallothionein and the studied metals. Therefore, according to the observations, changes in the concentration of metallothionein in this species are not affected by heavy metals and can be due to changes in the environmental conditions of the seasons.

In order to understand the pressure patterns cauaing the summer monsoon rains in the south east of Iran, daily values of pressure and wind components of 500, 700, and 850 hectopascal levels and sea level were obtained from NCEP site and daily rain data of 152 stations of Iran were provided by the Islamic Republic of Iran Meteorological Organization for 1970-2003 period. Spatial analysis of the rain data showed that there is a triangular area in the southeast of the country located to the east of 58:30 E and south of 28:30 N which gets rain every summer. This area is called an index area of Monsoon rains in Iran. The temporal analysis of the monthly rainfall of this index area indicated the June 1994 as the highest and most widespread rainfall during the study period. This study analysed the synoptic patterns causing this intensive rainfall period through the different atmospheric levels at the daily to seasonal scales.The results showed that: The Subtropical High Pressure was stronger and expanded east ward over India at the higher levels. At the same time at the lower levels the monsoon depression was expanded west ward over Arabian Sea creating positive vorticity over the area and making it possible for the air to ascend. The tropical easterly cyclones intruded the southeast of Iran in July1994 more than the other similar months. The westerly trough was deepened over the west of Iran. The south-westerly winds of Arabian Sea and Bay of Bengal became stronger. All these patterns and configurations caused the expantion of Monsoon rains to Iran and as a result very intensive rain happened over the area.