فهرست مطالب r. manaffar

Wetlands, as fragile water sources, are constantly affected by climate change and human activities. Recently, human intervention and the reduction of surface water in the catchment area of Lake Urmia have altered the microflora and physicochemical parameters of the wetlands, which need to be investigated. Results showed that phytoplankton populations of Darga-Sangi wetland consisted of Chlorophyta (2 classes, 10 families, and 22 genera), Cyanobacteriata (1 classes, 3 families, and 4 genera), Streptophyta (1 classes, 2 families, and 2 genera), Ochrophyta (2 classes, 2 families, and 2 genera), and Basillariophyta (4 orders, 6 families, and 10 genera ). In addition, pH value, Biological Oxygen Demand (BOD), and Chemical Oxygen Demand (COD) were investigated. The highest amount of BOD5 of Darga-Sangi wetland was estimated to be between 78 and 98 mg/l, while the highest amount of COD was 159 and 198 mg/l during the summer season. The results indicate that the high influx of organic and mineral substances into the wetland has affected its enrichment which resulted in blooming of microalgae and hence, rising ecological concerns. The bacterial load in this wetland puts it in an unfavorable condition, which can be dangerous for native and migratory organisms.

Urmia Lake is one of the largest permanent hypersaline lakes in the world. The lake can be characterized as an oligotrophic lake concerning phytoplankton production. Due to low precipitation in recent years in Urmia Lake’s catchment area, the water level has declined as much as 4 m compared to 15 years ago. Irrespective of its recent evolution, Urmia Lake has always shown fluctuations in historical and geological times, which may cause some ecological partition. Regarding allopatric speciation model of Artemia we assume that several populations of Artemia are generated during last years and living in Urmia Lake. To investigate Artemia population diversity in Urmia Lake, A. urmiana Günther 1890 cysts were collected from five sites in Lake Urmia, Iran. These sites in part represent areas with different physicochemical conditions. To detect possible differences between stations, discriminant analysis (DA) was performed on data of survival, growth, and reproduction at two salinities (75 and 150 g L -1 ) in laboratory culture tests. The performed DA implied that for the reproductive and life span characters, in both salinities, the stations of Golmankhaneh can be determined as the separated group among the studied stations which can be considered for industrial projects and evolutionary studies.

Due to the importance of identifying the major characteristics of Artemia populations, in this study some physiologic, biometric, nutritional and genetic characteristics of one Artemia population from Iran named Arak’s Artemia (Mighan Lake) was studied. The hatched larvae of Artemia were reared in the saline water of 80 g/l with standards method in which percentage of survival and growth were evaluated on days 3, 7, 11 and 15 of culture period. In order to study the morphometric characteristics of Artemia, diameter of full cysts as well as 11 more morphological parameters of adult Artemia were measured. The fatty acids profile were analyzed by gas chromatography. The Genetic characteristics were compared with other Artemia populations by sequencing after PCR amplification of Hsp 26 gene. According to the results, the diameter of cysts and nauplii instar were 276.28 and 544.66 micron, respectively. The growth and survival of brine shrimp Artemia, in comparison with other populations, reflected good growth and survival of this population. The results of fatty acids profile also showed higher amounts of polyunsaturated fatty acids in this Artemia compared to other populations cultured under identical conditions. The morphometric characteristics and genetic study of Hsp 26 gene showed great affinity of this population with the parthenogenetic brine shrimp Artemia. However, individual differences could be used to characterize this population.