Mehran Loghmani,
Volume 6, Issue 3 (4-2016)
Abstract
Chabahar Bay near Makran Sea, with the ports of transactions, has always been under the influence of annual monsoon the Indian Ocean. Density changes and heavy metals copper and zinc of Chabahar bay subtidal sediments were studied in 22 stations and three seasons that include: pre-monsoon, monsoon and post-monsoon during 2014. Polychaeta abundances mean were for premonsoon 1261.49±38.81, monsoon 513.81±65.6, postmonsoon 630.45± 73.84 ind/m2 that significant difference was observed between stations and seasons (p<0.05). Metals copper and zinc had fluctuations in three seasons, but despite the significant differences between the stations, there was no significant difference between seasons. Metals mean in preM, M, postM respectively for Cu include 19.89±3.34,14.42±4.47,12.9±3.4 and for Zn 73.42±5.51, 66.04±6.37, 61.72±4.86 µg/g dry weight that only in three stations and only in Cu, concentrations were higher than ERL but in total Chabahar bay metal mean were lower than ERL. Significance correlations were not observed between Polychaeta density and heavy metals except for copper in pre-monsoon. The results showed the impact of monsoon currents in the distribution pattern of polychaete and heavy metals and also were no significant differences in the relationship between density and concentration of can be as results of the low concentration heavy metals in sediments of international standards and other environmental factors on polychaeta density.
Maryam Akhoundian, Nadia Javandel, Fatemeh Kardel,
Volume 8, Issue 1 (7-2018)
Abstract
In order to investigate seasonal variation of diversity and abundance of Annelida, seasonal sediment sampling was performed on 10 stations with depths of 1, 5, 10 and 20 meters in the coastal area of Sari, Iran in 2015-2016. The results led to the identification of 8 genera and species of Annelida belonging to four families of Polychaeta and two families of Oligochaeta. The highest average annual abundance belonged to Streblospio gynobranchiata and the lowest average belonged to Prenereis sp. The average frequency of the Annelida was significantly and positively correlated with the percentage of the sand and the total amount of organic matter in sediments. The Shannon-Wiener and Margalef Indices showed that, the Annelida had the highest diversity in summer and the lowest species diversity in winter. The Simpson Heterogeneity Index showed the highest amount in the estuary on winter, and heterogeneity showed reduction with increasing the depth. The value of the brillouin index was increased along with the increase of the depth of the stations. The results of this research indicated that the diversity of Polychaeta and Oligochaeta in the study area is reduced compared to previous studies, while the prevalence of dominant species showed a significant increase.
