فهرست مطالب ali nasrolahi

Today, cigarette butts have become one of the most significant forms of waste. This study aims to assess the level of cigarette butts pollution along the Guilan coasts and explore the factors influencing their distribution. Additionally, this study discusses experiences and management options related to this issue.

In this study, we implemented a standard sampling method adapted from the "NOAA Marine Debris Program" to collect samples from eight beaches. Each station yielded 18 square quadrant measuring 1 × 1 m2. We estimated the severity of cigarette butt pollution along the Iranian coastline and conducted a review of published articles on the harmful effects of cigarette butts.

The density of cigarette butts ranged from 0.22 to 2.11 items/m2. Bojagh National Park showed the lowest contamination of cigarette butts, while Bandar Anzali exhibited the highest. The results indicate an increase in cigarette butt pollution on beaches in densely populated cities compared to less developed coastal areas. Moreover, stations corresponding to tourist beaches and coasts with gentle slopes have a higher potential for cigarette butt accumulation. The level of cigarette butts pollution along the coasts of Bandar Anzali may be attributed to the extensive tourism activities on these beaches.

Given the high level of cigarette butt pollution on crowded coasts, it is imperative to identify beaches with a higher potential for waste accumulation and implement plans for coastal waste cleanup. Furthermore, effective management programs should be developed to promote cultural awareness and reduce cigarette butt contamination.

The coverage of Persian Gulf coral reefs has decreased in recent years due to global scale stressors such as global warming and acidification of oceans and local stressors such as ecotourism and coral diseases. This condition is often associated with the overgrowth of algae and other benthos and impairs the ability of coral communities to regenerate. However, the evidence suggests that coral reefs can essentially be recovered in the absence of stressors and destructive agents, provided that the larvae settle properly on the bed and among biofouling organisms competitors. Therefore, studying the interaction of nutrients and grazing as a precondition for coral larvae settlement is very important in determining the health of coral reefs and benthic population structure in management discussions. In order to determine the relative importance of nutrient and grazing on the settlement pattern of hermatypic corals and other epibenthic communities in the coral reefs of Hengam Island, experimental manipulations was designed and performed in four treatments in terms of nutrient s and grazing parameters. The beginning of this research was from autumn 1398 to the end of summer 1400 in four time periods of spring, summer, autumn and one year-period-panel on ceramic panels with a size of 20×20 cm for 21 months. The statistical results show the predominant effect of the nutrient parameter in controlling the subsidence of benthic communities compared to the grazing parameter in coral ecosystems of Hengam Island. This reflects the fact that the studied coral ecosystems of Hengam Island are mainly driven by a "bottom-up control" mechanism. According to the present study, it can be concluded that if by adjusting the global and local stressful conditions, the coral reefs of Hengam Island are in the direction of regeneration and restoration, the intensity of grazing in the case of s high levels of nutrients will not be able to remove algal biomass and competing biofoulings, and coral larvae will not be able to settle and spend post-settlement phase successfully.

This study aimed to achieve length frequency, condition factor and length-weight relationship of the rock oyster, Saccostrea cucullata in the coastal waters of Persian Gulf. Sampling was carried out by 0.25 m2 quadrat through intertidal zone from winter 2015 to autumn 2016. According to the results, length-weight relationship calculated as W=0.000004L2.79 for both sexes. In addition, coefficient of determination (R2) value was determined as 0.94. Furthermore, b value was significantly different from 3. Condition factor was estimated as 14.36, 16.87, 20.85 and 20.76 for autumn, winter, spring and summer, respectively. Mean length and weight were 34.4±4.96, 36.8±8.46, 30.25±7.1 and 33.31±4.31 cm and 8.9±7.57, 10.4±9.8, 10.9±6.11 and 7.8±4.19 g in spring, summer, autumn and winter , respectively. Maximum and minimum length were 97mm and 2 mm in spring and autumn, respectively. Maximum dry weight was found in winter (2.21g) and the minimum was determined in autumn (0.009 g). Maximum length frequency was observed in the 35-45 mm range class in all seasons. However, range class of 40-45 mm was also frequent in the spring. According to the nMDS results based on length and weight ordination, autumn was distinct from all seasons probably due to the juvenile recruitments in this season.

Biofouling is applied to the colonization, accumulation and growth of living organisms on different substrata exposed to aquatic environment. These structures include natural and artificial substrates. Biofouling communities are both economically and ecologically important. Biofoulers have basic role in transferring of energy in food chains and ecosystems functioning. Also, these communities by creating multi-dimensional substrates provide different habitats for other organisms. In economic aspects, colonization of these organisms on ship hulls, boats, aquaculture cages and marine structures such as pipelines can cause economic damages (Yebra et al., 2004; Schultz et al., 2011). In spite of all these, there are little information about these communities in the Caspian Sea and there is almost none in the Iranian coast of the Caspian Sea. This study was conducted in May 2015 till May 2016 in Astara port to investigate the effect of substrate surface on temporal variation of biofouling assemblages. Five replicates of PVC panels (12×12×0.3 cm) were deployed horizontally at 1m depth. The panels were retrieved and replaced with new series every 2 months for a period of one year. At each sampling event, upside and underside of the panels were photographed separately and then analyzed using CPCe software (Kohler and Gill, 2006) for cover percent of each surface. The biomass and inorganic to organic ratio were calculated using dry and ash weight. In total, 6 major groups including barnacles, bryozoan, algae, polychaete, mussels and hydroids were identified. Amphibalanus improvisus was the most dominated species in this study and was observed all year round. Cheilostome and Ctenostome bryozoans were the second dominant groups. These two groups mostly derived the temporal variations in studied communities. Two-way ANOVA analysis showed that the period of submersion and the surface have significant effect on cover percent, total biomass and inorganic to organic ratio of fouling communities (p