Gahar Lake is located in the center of the protected area of Oshtorankooh in Lorestan province. This lake is a unique high-mountain lake "Paternoster or Lord's Prayer" with two water body connected by a stream. There is not any research and published study about limnology, biology and taxonomic composition of its organisms. This study is the first one and a part of a complete investigation on planktonic community and trophic status of GaharLake. SmallGaharLake is a shallow water body and submerged macrophytes have covered entire the lake. So this study was conducted to introduce cladoceran species composition of small macrophyte dominant lake. Zooplankton assemblage was sampled from open waters and near macrophytes using a 30 micron net, filtering 100 liter water, during a period of 1 year from Ordibehesht 1389 to Ordibehesht 1390 (except 3 months of ice period) The Cladoceran taxa composition of small Gahar Lake revealed 14 species. These species belong to 2 families and 6 genera including: Simocephalus expinosus var.? , Simocephalus expinosus , Simocephalus vetulus , Chydorus sphaericus , Chydorus faviformis, Chydorus latus Ceriodaphnia reticulata , Alona quadrangularis Alona affinis, Alona gutata, Alonella diaphana, Alonella sp., Scapholeberis kingi, and Pleuroxus hamulatus.

This study is the first attempt to investigate some diatom species in the western rivers of Lake Urmia. The study presents the details of Encyaonema, Craticula, and Cymatopleura at the lowest taxonomic level to provide information in terms of species taxonomy, morphology and ecology. In order to determine the morphological similarities in species level of the aforementioned genera, 14 sites were repeatedly sampled along the rivers from September 2021 to August 2022. The results showed a high diversity of diatoms including Encyonema caespitosum. Encyonema silesiacum, Encyonema prostratum, Craticula cuspidata, Craticula ambigua, Cymatopleura solea, Cymatopleura apiculata, Cymatopleura hibernica and Cymatopleura elliptica. The taxonomic and ecological study of the observed species from the western rivers of Lake Urmia indicates diatom assemblage closely integrated with the limnology and ecological status of the rivers. Indeed, the results infer that the rivers undergo a transition from freshwater to brackish, particularly where the rivers terminate at Lake Urmia.

Nais variabilis is cosmopolitan oligochaete worm and is common to fresh and brackish water habitats. This species has not been reported from Iran freshwater fauna and South Caspian Sea before and it was found while investigating limnology of Cheshmehkileh and Sardabroud rivers and estuaries alongside the Iranian coasts. Nais variabilis was collected bimonthly from November 2014 to September 2015 using a Van Veen grab (0.03 m2) and Surber (0.1 m2, 0.2 mm-mesh size) with three replicates at 6 stations. Results of temporal distribution showed that the highest and lowest density and biomass of this species were in November (118.8 ±79.8 ind/m2 and 0.075 ± 0.034 gr/m2) and in September (26.5 ±9.8 ind/m2 and 0.015 ± 0.005 gr/m2) respectively which were significantly different (P<0.05). Among sampling stations, freshwater stations (S1) within the river showed higher density and biomass (139.4 ± 83.3 ind/m2 and 0.08 ± 0.029 gr/m2) than brackish stations (S2) (21 ±10.6 ind/m2 and 0.015 ± 0.006 gr/m2) and marine stations (S3) (0 ±0 ind/m2 and 0 ± 0 gr/m2) which were significantly different (P<0.05). Density and biomass of this species in Cheshmehkileh River and estuary was more than Sardabroud. A significant correlation (P<0.05) between the density and biomass of N. variabilis and environmental variables were found.

It is essential for the proper management of lakes to know physical and chemical factors in their different parts and in different times of the year. This project aims to investigate basic limnology of physical and chemical factors in Salman-Farsi Reservoir, Ghir County, the Province of Fars. Seasonal samplings were carried out in 2007 in 27 stations. Analysis of variance was used to compare seasonal variations of the studied factors. The annual means of the studied items were as following: water temperature (22.6° C), dissolved oxygen (8.2 ppm), carbon dioxide (0.9 ppm), pH (7.8), transparency (352 cm), electrical conductivity (874 µS/cm), total dissolved solids (570 ppm), total hardness (630 ppm), nitrite ion (0.02 ppm), nitrate ion (0.8 ppm), ammonia (0.04 ppm), phosphate ion (0.4 ppm), biochemical oxygen demand (3.8 ppm), and chemical oxygen demand (19.3 ppm). Comparison of the results with the drinking water standards showed that the lake water is suitable regarding pH, electrical conductivity, total dissolved solids, ammonia, nitrite, and nitrate concentrations, but its total hardness was slightly higher than the permitted values. Temperature, pH, dissolved oxygen, electrical conductivity, total dissolved solids, carbon dioxide, nitrite, nitrate, concentrations as well as biochemical oxygen demand showed acceptable levels all over the lake as compared with water quality standards for warm-water aquaculture. Chemical oxygen demand measures were at proper levels in the lacustrine and transitional sections, but slightly higher than this level in the riverine areas. Ammonia levels were appropriate in the lacustrine but moderately higher in the riverine and transitional sections. Transparency, total hardness, and phosphate ion concentration were much higher than the standard levels of warm-water aquaculture.

The cosmopolitan oligochaete worm, Nais elinguis, is common to fresh and brackish water habitats. This species was found while investigating the limnology of two rivers alongside the Iranian coasts and has not been reported in the Iranian freshwater fauna and Caspian Sea before. N. elinguis was collected bimonthly from Cheshmehkileh and Sardabrood estuaries using a Van Veen grab (0.03 m2) and Surber (0.1 m2, 0.2 mm-mesh size) with three replicates from 6 stations from November 2014 through September 2015. The results of temporal distribution showed that the highest and lowest density and biomass of this species were in January (242.2±84.45 ind m-2 and 0.105±0.035 g m-2) and in September (33.35±23.5 ind m-2 and 0.010±0.006 g m-2) respectively which were significantly different (p<0.05). Among the sampling stations,  station (S1) within the river with freshwater showed higher density and biomass (273.5±87.35 ind m-2 and 0.116±0.036 g m-2) than riverine brackish station (S2) within the mouth (39.8±22.6 ind m-2 and 0.013±0.006 g m-2) and marine brackish station (S3) (0±0 ind m-2 and 0±0 g m-2) which were significantly different (p<0.05). Density and biomass of this species in Cheshmehkileh River and estuary were more than that in Sardabrood. A significant correlation (p<0.05) between the density and biomass of N. elinguis with environmental variables was found.

Water quality is presented by its physicochemical and biological specification. The aim of this study was to analyze the physicochemical characteristic of waters (river, drinking, hybrid and pure water) including total hardness, magnesium, nitrite and ammonia (mg/L) which were determined based on the standard protocols of the EPA (2010) using photometer, Palintest, 8000. Furthermore, dissolved oxygen (mg/L), temperature (ºC) and pH were determined by oxygen meter, calorimeter and pH meter, respectively, with 3 repeats and in the limnology laboratory of Birjand University. In river water, the concentration of nitrogen is higher compared to other water sources due to the physicochemical reactions (especially due to the disposal of ammonia into water). For the hybrid water, consisting of drinking water plus pure water, the chlorine concentration (0.4 mg/L) was greater than the average (0.15 mg/L). The total hardness of the same (125 mg/L) was however lower than the average (185 mg/L). Finally, it is recommended that biological indicators such as the presence of rotifers, tubular cross-sectional fish, and salmon (which normally live in clean water) be used to assess the qualitative characteristics of the water. This is due to the fact that there are normally more living creatures in waters which can hold salts.

Marine and lake terraces are the base for Climate Geomorphology Investigations Especially in Quaternary. These Terraces are important not only for climatic aspects but also, they can show a lot of truth in earth and environment evolutions History, Archeology and Human History. .The Urmia Lake because of unstable development and climate change, faced to serious roughness. In order to analysis water level fluctuation of this lake, we need comprehensive study in Urmia paleolimnolgy and investigation other factors such as Human, Climate, Geomorphology, sedimentology and geology that affected this lake.Quaternary sediment boundaries in coastal plain Paleo Lake Coastline was mapped using GIS and RS. for study area. Probability location of Plaeo Lake terraces was drowning using satellite images. In field work besides sampling, lake terraces were investigated in aspect of material, granolometry, color and specially fossils.. Finally paleo lake level reconstructed on satellite images and area that affected by increase paleo lake level was determined One of the most important evidence to reconstruction of the Urmia lake palogeomorphology and paleo limnology is lake terraces; This research was done with focus on identification and determination ages of Urmia paleo lake level in order to achieve changes in eustatic and water volume in Late Pleistocene Sedimentological and geomorphological studies of terraces around Lake Van provided a preliminary framework for lake-level variations. In field studies, 24 lake terraces were found in Quaternary sediments. Lowest terraces are located in Islami Island in elevation of 1297 meters and the highest terraces in Damirchi with elevation of 1366 meters Available data suggest that the long-term lake-level changes responded mainly to climate oscillations. Keyword: 14C Dating, Lake Terraces, Late Pleistocene, Urmia Lake

Shahdadroud River is one of the most important rivers in Kerman province that during previous years has been threatened by drought and anthropogenic pollution. This river supplies some parts of drinking water of Kerman city and some vicinity villages. The main objective of the present study is consideration of pollution situation of the river; for this purpose, limnological and biological studies of the river were carried out seasonally in 2007. Four sampling stations including Vameghabad (station 1), Bamoghavemat (station 2), Sharifabad (station 3) and Mehrechenar (station 4) were determined based on limnological standard method along the river; afterwards sampling of invertebrates (biological index) and water quality (BOD) were performed seasonally during study period. The results showed that station 1 is free of pollution while the station 2 is the most polluted region at the river; because the station 1 has no pollutant resource but the station 2 receives wastewater of rainbow trout fish culture center directly. Based on findings of biomonitoring and water BOD measurement, Shahdadroud River has relatively high-polluted situation and is classified in? -mezosaprobe class.

Aquatic environments, including wetlands, are one of the most threatened ecosystems worldwide. Considering their ecological importance, wetlands are rightly appraised as ‘natural kidneys’. In this current study, the city wetlands of Guwahati were viewed for the first time through the angle of lesser-explored bottom dwellers. Guwahati, a rapidly expanding metropolis, is the gateway to northeast India, part of an Indian biodiversity hot-spot region. This case study comprised the bridge between abiotic and biotic factors, thus directing the pave for characterization of wetlands through benthos analysis. The study, covering seasons, viz. winter, premonsoon and monsoon, revealed 15 definite taxa belonging to 10 orders. The dominance of Chironomidae and Culicidae in certain wetlands indicated high tolerance of Dipterans in a wide range of aquatic environments, including polluted water bodies. Similarly, the presence of Trichopterans, only in the wetland located distant from the mainland city, marked that with less anthropogenic impacts. The Shannon indices for benthos were in the range from 0.17 to 0.97. Density was found to have a significant positive correlation with dissolved oxygen (r = 0.567) and a negative correlation with free carbon dioxide (r = -0.377). In contrast to significant site- wise variation in density, there was no significant difference in benthic diversity across the sites and no significant seasonal variation of benthic density and diversity from the statistical point of view.

Odonate larvae play an important role in macroinvertebrate trophic networks and are excellent proxies for wetland quality. However, despite their ecological importance, research on odonates and how they interact with their environment is scarce. This study aims to assess macroinvertebrate composition as determinants of larval abundance in Miathyria marcella (Odonata: Anizoptera: Libellulidae).

29 samples were collected from six wetlands with different hydrological influence using standardized invertebrate sampling techniques in the Department of Atlántico, northern Colombia. Standardized invertebrate sampling techniques were used in 29 sampling points. Obtained data were used to analyze invertebrate abundance and a non-parametric multidimensional scaling analysis was applied. In addition, a correlation analysis was conducted between macroinvertebrate composition and Miathyria  marcella larval abundance.

A total of 2586 larvae, and 12925 individual macroinvertebrates were collected, distributed in 25 orders and 58 families. The most abundant orders were Neotaenioglossa (26 percent), Odonata (15 percent) Calanoida (10 percent) and Diptera (8 percent). Heatmap and scaling analysis indicated different macroinvertebrate compositions in the sampled wetlands. A high positive correlation between Miathyria marcella and the orders Odonata (R2 = 0.84, p-value ≤ 0.05), Coleoptera (R2 = 0.52, p-value ≤ 0.05), Basommatophora (R2 = 0.60, p-value ≤ 0.05) and Hemiptera (R2 = 0.50, p-value ≤ 0.05).

The results suggest that the abundance of Miathyria marcella responds to the accompanying macroinvertebrates, the composition of which depends on the type of hydrological influence. Approaches focused on the relationships between macroinvertebrate taxa are important conservation tools for biodiversity assessment. Results from this study will serve as a baseline to propose monitoring and follow-up strategies on the environmental sustainability in wetlands in this region.