Miankaleh international wetland and peninsula are one of the main UNESCO biosphere reserve in Iran and Middle East. PHYTOPLANKTON diversity of the Miankaleh wetland was investigated from October 2009 to September 2010. Apart from the work done by Ramezannejad Ghadi, this study is the second floristic study of algae in the Miankaleh wetland in north of Iran. Five main algal groups were recorded namely: Bacillariophyta, Cyanobacteria, Chlorophyta, Euglenophyta and Xantophyta. A total of 94 species and varieties belonging to 47 genera were identified. Among them green algae formed the most abundant group making up 43 species and varieties from 18 genera. This was followed by Diatoms, with 31 species from 15 genera, Cyanobacteria, with 18 species from 12 genera. Euglenophyta and Xantophyta with 1 species make up an insignificant part of taxa. All of these taxa are new records for Miankaleh wetland and Mazandaran province.

PHYTOPLANKTON plays a major role in monitoring aquatic ecosystems. The purpose of this study was to investigate the relationship between the density of PHYTOPLANKTON and the nutrients, especially nitrates and phosphates and other effective parameters in Karaj dam as a case study. For this purpose, in 2010, Karaj dam was sampled during a year and physical, chemical and biological factors were measured. The penetration depth of sunlight into the water, was measured using Sechei disk. The results of this study demonstrated that there is a thermal stratification in Karaj reservoir. The density of PHYTOPLANKTON in this lake increased in hot weather of the year and it also varies as the depth increases. In 2010, the most population in PHYTOPLANKTON community of the lake was formed by Diatoma and specially Cyclotella. No relationship was found between the number of PHYTOPLANKTON and the amount of chemical factors in this study.

The Limnological study of Arasbaran reservoir dam in Eastern Azerbaijan province was carried out in order to aquaculture purposes. Hydrochemical parameters and PHYTOPLANKTON samples were collected three times in 2010. Totally, 37 genus were identified that belong to 6 phylum Chlorophyta, Cyanophyta, Bacillariophyta, Euglenophyta, Pyrrophyta and Chrysophyta. Chlorophyta had the most diversity of PHYTOPLANKTON genus with 14 genera. The identified genera for other phylum were 6, 12, 2, 1 and 1 genus, respectively. Cyanophyta had the most abundant of PHYTOPLANKTON with average 23. 5 million/l. and 72% of total population. The second ranks of PHYTOPLANKTON abundance belong to Bacillariophyta phylum with 22% total population and Cyclotella, Achnanthes and Synedra were dominant genus. While no significant difference (P>0. 05) was observed for PHYTOPLANKTON abundance in different depths, a significantly difference (P<0. 05) was observed for PHYTOPLANKTON abundant among different sampling times and furthermore among different stations. The average values of electrical conductivity (Ec), temperature, dissolved oxygen and pH was varied from 717 to 1073 µ s/s, 6. 8-24. 4 ° C, 1. 1-12. 8 mg/L and 7. 62-8. 75, respectively. A thermo-oxy stratification was observed at 10 meter depth in June.

The need for predictive water quality modeling has arisen largely as a result of increased eutrophication of lakes throughout the world. In 1919 Nauman introduced the concept of oligotrophy and eutrophy, distinguishing oligotorophic lakes with little panktonic algae and eutrophic lakes containing much PHYTOPLANKTON. The PHYTOPLANKTON consist of the assemblage of small plants having no or very limited powers of locomotion. A variety of formulations have been developed to represent the effect of temperature, light, and nutrient on PHYTOPLANKTON growth. A number of processes contribute to the loss rate of PHYTOPLANKTON. These processes are: respiration, excretion and predatory losses. The zooplankton includes animals suspended in water with limited power of locomotion. PHYTOPLANKTON as well as zooplankton are usually denser than water, and constantly sink by gravity to lower depths. System dynamics is a method of solving problems by computer simulation. The typical purpose of a system dynamics study is to understand how and why the dynamics of concern are generated and to search for managerial policies to improve the situation. In this paper PHYTOPLANKTON and zooplankton are simulated by system dynamics approach. Then we integrated a limiting nutrient into our PHYTOPLANKTON-zooplankton scheme to complete our fundamental picture of how nutrient/food-chain interactions are modeled.

Gandoman wetland is one of the main aquatic ecosystems of Chaharmahal and Bakhtiari province in the mid western of Iran. It is located close to Choghakhor international wetland. The PHYTOPLANKTON diversity of the Gandoman wetland was investigated in four consequensive seasons from September 2006 to August 2007. This is the first floristic study of PHYTOPLANKTON in this wetland. Six divisions of algae, Bacillariophyta, Chlorophyta, Cyanobacteria, Euglenophyta, Dinophyta and Chrysophyta had the main abundance respectively in studied sites. In total 95 species and varieties belonging to 54 genera were recorded. Bacillariophyta was presented with 51 species and varieties as the most abundant group, followed by Chlorophyta, with 18 species and 12 genera. According to this study, Gandoman wetland present an acceptable diversity of PHYTOPLANKTONs according to the published algal checklist of Iran.

This study was carried out to investigate the PHYTOPLANKTON composition in Gorgan Bay. Water samples were collected from 11 selected sites in Golestan bay, monthly from March to February. Thirty five genus were identified among which Bacillariophyta was the dominate group with 17 genus, while the Euglenophyta had the minimum. Abundance and biomass of PHYTOPLANKTON showed spatial and temporal variations in the Bay. After Bacillariophyta, Cyanophyta was the most dominant group in spring, summer and autumn, while the Pyrrophyta was the most dominant in winter. Moreover, the highest number were counted for Nitzschia sp and Gyrosigma sp in spring, Gyrosigma sp, Euglena sp and Anabaenopsis sp in summer, Anabaenopsis sp and Prorcentrum sp in autumn, and Cheatoceros sp and Cyclotella sp in winter. Maximum abundance and biomass were calculated for site 8 (near Khozeini Channel) and the minimum were in sites 1 and 3 (central part of the bay) respectively. The average values of Margalef, Simpson and Shannon-Wiener indices were 0. 3± 0. 27, 0. 37± 0. 25 and 1. 22± 0. 75 respectively, indicating low diversity in Gorgan Bay. The maximum Margalef (0. 99), Shannon-Wiener (2. 77) and the minimum Simpson (0. 07) indices were calculated in February. Results of RDA showed that water temperature, water depth, transparency, phosphate, nitrate, pH, total alkalinity and dissolved oxygen had significant, high correlation with abundances of different PHYTOPLANKTON genus.

The present paper deals with a toxin producing PHYTOPLANKTON (TPP) -zooplankton interaction in spatial environment in the context of PHYTOPLANKTON bloom. In the absence of diffusion the stability of the given system in terms of co-existence and hopf bifurcation has been discussed. After that TPP-zooplankton interaction is considered in spatiotemporal domain by assuming self diffusion in both population. It has been obtained that in the presence of diffusion given system becomes unstable (Turing instability) under certain conditions. Moreover, by applying the normal form theory and the center manifold reduction for partial differential equations (PDEs), the explicit algorithm determining the direction of Hopf bifurcations and the stability of bifurcating periodic solutions is derived. Finally, numerical simulations supporting the theoretical analysis are also included.

Sampling was conducted seasonally from three stations (A1- upstream; A2-intermediate; A3- downstream) along reservoir from June 2007 to March 2008.PHYTOPLANKTON population changes were investigated in order to calculate PHYTOPLANKTON indices in each site. In the present study, 46 algal species were determined. These were belonged to five classes: Diatoms (Bascillariophyta); green algae (Chlorophyta); bluegreen algae (Cyanophyta); Pyrrophyta and Euglenophyta. The water quality in sampling sites was studied based on the more utilized ecological indices such as Index of Dominance, Richness, Shannon-Wiener species Diversity index and evenness index.The lowest values of Species diversity index was observed in the summer. Evenness index showed the lowest values during summer and higher values in the spring. The present study revealed that Aras Dam reservoir is eu-hypertroph water.

Mighan lake with the surface area of 112 km 2 is located eight kilometers northeast of Arak city, the main PHYTOPLANKTON population and food chain of which include Dunaliella salina (Dunal) Teodoresco. The salinity of the lake ranges between 20-120 g/l depending on season and water input. The present study evaluated the effect of salinity and physicochemical factors on PHYTOPLANKTON communities in the lake. To this end, sampling was performed monthly during March to December 2019. In addition, species and PHYTOPLANKTON density were determined through inverted microscopy. Based on the results, 12 algal species were identified, among which D. salina was 87. 3% of PHYTOPLANKTON composition. Indeed, salinity, as a major limiting factor, reduced phyto-plankton diversity in Mighan Lake.