seyed mohammadbagher nabavi

Nayband Bay has been greatly influenced by a variety of human disturbances over the last three decades. The present study was undertaken to assess the ecological quality status of macrobenthic communities in Nayband Bay sediments using four benthic indices namely AMBI, M-AMBI, BENTIX, and H´. The sediment samples were taken for macrobenthos extractions and determination of grain size analysis, Total Organic Matter (TOM), and Total Organic Carbon (TOC) using a Van Veen grab. A total of 47 macrobenthos taxa (genus and species) were identified among 34825 individuals in the sampling area. Polychaeta, Malacostraca, Bivalve, Gastropoda and Echiura were the most abundance taxon with 23 (48.9%), 11 (23.4%), 6 (12.7%), 5 (10.6%), and 2 (4.2%) species. The results showed that the macrobenthic communities were characterized by sensitive (EGI) or indifferent (EGII) species of AMBI ecological groups. The opportunistic species (EGIV and V) namely Capitella capitata, Cirratulus ciratus, and Scolelepis sp. were dominated at stations with high TOC. These stations were close to the beach, where the organic matter discharges and wastewaters have been released from industrial outfalls. In general, the EcoQs were “good” or “acceptable”, although four indices showed some differences in the EcoQs classifications for a given site. The results of the present study indicate that the complementary use of different indices, especially sensitivity/tolerance-based indices, is recommended for the ecological-status assessment of the Iranian coastal waters of the Persian Gulf.

Investigating the trend of temperature changes occurring in the Persian Gulf can be used to determine the pattern of climate change in the region and to study the impact of these changes on aquatic habitats in the Persian Gulf waters.  This study was carried out to investigate the changes in sea surface temperature and sea surface temperature anomaly in Kharg and Hendourabi islands by using Environmental Research Division's Data Access Program (ERDDAP) of National Oceanic and Atmospheric Administration (NOAA) and  daily sea surface temperature and sea surface temperature anomaly  were investigated over a 35-year period.The results showed that the average annual surface temperature increased by about 1 °C over 35 years in Kharg and Hendourabi Islands and the average annual sea surface temperature anomaly in these islands were increased by 2 °C. The slope of this increasing trend on Kharg Island was more severe than Hendourabi Island. The most significant bleaching event in the Persian Gulf occurred in 2016-2017, with the highest increase in temperature in 2017. As water temperatures continue to increase in the coming years, the living conditions of the Persian Gulf corals are likely to deteriorate, and only some resistant species can survive in the Gulf.

The most common marine environmental pollutants are metal pollutants, petroleum hydrocarbons, and aromatic hydrocarbons. In the present research, metallic and organic pollutants of Nayband Gulf were investigated. Sampling was done from 20 stations in the winter of 2018. From each station, two sediment samples for organic matter and heavy metals (with 3 replications) were collected and a total of 120 sediment samples were collected using Van Veen Grab. To measure metals and petroleum hydrocarbons, ICP(Agilent7500cx) and GC (Agilent 6890n) devices were used, respectively. Data were analyzed using SPSS 22 software. The mean concentrations (mg/kg) of iron (7980), nickel (19.71), vanadium (14.90), and cobalt (5.71) were measured. Although it did not exceed domestic and international standards, nearby stations Asaluyeh region showed a significant difference (P<0.05) with other stations. The total amount of petroleum hydrocarbons (TPH) with an average of 14.33 mg/kg and the maximum concentration of 42.16 were recorded at a station (19) near Asaluyeh wharf and the amount of polycyclic aromatic compounds (PAH) with an average of 223.09 µg/kg and maximum concentration of 657.68 were recorded at a station (20). Based on the data, Nayband gulf has low levels of pollution (TPH> 15) in terms of TPH compounds and moderate levels of pollution (PAH> 100) in terms of PAH compounds. The difference between stations near Asaluyeh and other stations in terms of pollution shows that the gradual increase of pollution caused by industries and its impact on the functioning of Nayband gulf ecosystem should be considered as a serious issue.

The present study investigates the water quality of Sufi Chay river in Maragheh, Iran using Benthos groups and their population structures in 2015.

Overall, 9samplingsites were selected in the region and Macrobenthos were sampled in triplicate at each siteusing a 25×50 surber. The samples were stabilized by Formaldehyde 4% and their species, family and genus were identified. A total of20Macrobenthos species from 19 families, 10 orders and 2 classes were evaluated. Baetis sp. was the dominant species in winter and summer.

The results indicate that the 7 and 9 sites with the aggregation of 47 and 128 Macrobenthos per m2 were dominant in winter and summer, respectively. Regarding Welch model, water quality of Sufichay river was moderate at most sites in both seasons. However, the water quality at the 7 site in winter and the 8 and 5 sites in summer was unsuitable. According to the BMWP Index, water quality of the river, except the 8 and 9 sites in winter, was suitable.

Regarding the results of this research it can be concluded that Macrobenthos community is an effective bioindicator to assess environmental conditions of the Sufi chay river. In addition, the results of this study display the relatively suitable water quality of Sufi Chay river.

The present study was carried out to investigate the diversity and distribution of the Polychaeta species in the Qeshm Island and the effect of desalination plants on their communities. The desalination plants provide a large portion of Qeshm Island drinking water. So, their waste waters could effect on environment especially benthic animals near the coastline. Substrate sampling was carried out in summer and winter 2014 from 9 stations. Station 1 was situated near (desalination site) with the highest temperature and salinity in both summer and winter season, which shows the effects of drainage waste water on environment condition. The substrates of the most stations were silt-clay. At the stations 4 and 5, which sediments included more silt and clay, organic matters were higher than other stations. In this study 49 genera and species were identified. There was a significant negative correlation between the polychaetes abundances and sediment content of silt and clay observed. The higher abundances of polychaetes were found in the stations with lower content of organic matters and greater grain size sediments. The genera Cossura sp. and Scoloplos simplex which related to Cossuridae and Orbiniidae families respectively were dominant specimens. The lowest level of diversity was estimated in station 1. Diversity and dominance indices at stations near the wastewater outlet showed significant differ in both seasons (P<0.05). Finally, it seems that desalination plant may affects adversely on species diversity by increasing of temperature and salinity in short distances.

Although rocky oysters are widespread throughout the world, they are still difficult to identify and classify due to their high levels of plasticity. Unlike morphological classification, molecular methods can help identify and classify species whose morphological characteristics are misleading. In this study, 15 dominant rocky oyster specimens were collected from intertidal areas of northern part of Persian Gulf to investigate the gene sequence. DNA was extracted from muscle tissue using CTAB (Hexade cyl trime thyl ammonium bromide) method. Sequences of unit 1 nucleotides of cytochrome oxidase gene (COI) were examined. The sequences of the studied samples were compared with the sequences of eight other species in the gene bank by phylogenetic tree mapping. The percentage of Bootstrap endemic to Saccostrea mordax is located in a clade, indicating that the COI sequence is suitable for identifying the species of Saccostrea oistre, and this species has also been reported for the first time in this area.

Polychaetes are ecologically important in the food chain, and also vital in ecosystem monitoring and environmental stress assessment. In the current study, sequence variation in a segment of COI gene sequencing by mitochondrial DNA barcoding and comparing nucleotide divergence was employed for molecular analysis of Perinereis polychaetes (Nereididae). Analysis of 50 sequenced specimens, representing 39 new sequences, and 11 sequences with 100 percent similarity with GenBank records, which revealed 1.8 times more sequence divergence between than within species (1.96 versus 3.52%). Phylogenetic analysis data indicated that maximum divergence within barcode clusters increased by the number of specimens. The phylogeny also suggests that most of the identified Perinereis species in this research showed low genetic relationship towards similar species from other world regions. Assessment of genetic similarity rate showed that Perinereis polychaetes in Bushehr province were highly similar, while Perinereis polychaetes in Bandar Abbas were less similar to Bushehr Perinereis polychaetes, the observed divergence was mostly at subspecies level and it can be concluded that in terms of species structure, Perinereis polychaetes of Deylam, Bushehr, Dayyer and Bandar Abbas, showed low genetic divergence.

The majority of the Earth's surface is covered by water bodies whose beds provide very diverse habitats for aquatic. Since benthos communities choose particular type of bed as their habitat, study of sediments and organisms in the substrate environment can help the environmental assessments. This study was performed to assess the ecological condition of the muddy substrates using macrobenthos communities in Sajafi region of the Persian Gulf. Sampling was done in fall 2009 at 20 stations with 3 replicates at each station to determine organic matter and grain size of the sediments. Measurement of water chemical and physical factors and identification of macrobenthoses were carried out using Hach-HQ40d and Grab devices. Diversity indices of Shannon - Wiener, Simpson, Camargo uniformity, Margalef and Menhink species richness were calculated. Nonparametric Kolmogorov-Smirnov test was used to evaluate the distribution of the data, the oneway ANOVA and Spearman correlation tests were used to compare and evaluate the relationships among diversity and density indices, chemical and physical factors and sediment parameters, and Welch pattern was used for assessing the environmental pollution. Totally 8 groups of Benthos comprising 81 species were identified. The most frequency percent belonged to Gastropoda with 43.03%, Polychaeta with 29.31 % and Bivalvia with 20.53%, respectively. The highest value of Shannon index at station 11 was 4.523. The highest values ​​of diversity and dominance of Simpson, Camargo evenness, and Margalef and Menhink richness indices were 0.948, 0.158, 0.828, 5.830 and 2.830 respectively. The maximum and minimum values ​​of frequency were 4920 and 560 macrobenthos per square meter, at Stations 10 and 17 respectively. Discussion and According to the results of the measured indices, which confirmed the high diversity of macrobenthos in the muddy bed of Sajafi area, it can be concluded that the study area has a high potential to preserve the environmental richness of benthic invertebrates.

Stress reduce animal’s fitness with affecting to animal’s metabolic function, the aim of this research was to study of stress controlling function of C.Umbonella in exposure to change in grain size sediments at Kangan and Assaluyeh coastline. Five sites including 11 stations were selected. Regarding to measurement of antioxidant enzymes, Soft tissue of 192 records were extracted. Higher value of CAT enzyme reported in stations at the near stress point in site 1 (49.76 ± 1.48 U mg-1 P) and site 2 (49.64 ± 7.51 U mg-1 P). unlike to values of GR and GPx enzymes, there were no significant difference (significant value 5%) in values of CAT and SOD along to the sites and stations. proposed that CAT and SOD enzymes have better efficiency during Alarm stages but GR and GPx are more effective along the Resistant stage in exposure to stress.

The molecular phylogeny of Vetigastropoda species have been studied based on mitochondrial genes, COI and 16S rRNA in the present work for the first time in the northern rocky coastal zones of Persian Gulf during years 2013 and 2014. After morphological identifications of species, DNA extraction, amplifying partial of cytochrome oxidase COI and 16S rRNA and sequencing procedure were done in the laboratory. In this study 9 COI and 5 16S rRNA sequencing belonging to 5 species were measured. Also, phylogeny analyses with drawing phylogeny trees of Maximum Likelihood, Maximum Parsimony and Bayesian were done using MEGA6, PAUP and BEAST softwares. The result showed that clade Vetigastropoda, include Trochidae, Chilodontidae, Turbinidae and Fissurellidae families, is not monophyletic, which is not as classic identification. So Trochidae and Chilodontidae are in seprated clade from Turbinidae and Fissurellidae clade᾽s. This showed not monophyletic relation between this two group which represented difference between classic and molecular classification.

Heavy metals, especially mercury due to its toxicity, persistence and the impact on aquatic organisms is important in terms of public health noteworthy. This study aimed to assess mercury concentrations in surface sediments of estuaries Mahshahr, Khuzestan province, eight stations were selected and three sediment samples were collected from each station. Sampling operations were conducted in January 2016. After laboratory analysis, the content of mercury using cold vapor atomic absorption technique was measured. The average concentration of mercury in sediments of stations studied in the range of 90-490 was nanogram per gram. High levels of mercury were found in petrochemical estuary and with increasing distance from this estuary, the pollution of the gradually decreased. In general, the calculation for regional factor pollution, pollution is too severe for most stations showed, while According to global factor pollution was low to moderate.

In this study, providing a predictive model for the presence or absence of a few dominant macrobenthic species in a tidal area of mouth of the Bahmanshir River were evaluated. Sampling of the region to identify and count species and also measure the amount of TOM and grading of sediments was carried out. After identifying and counting macrobenthic species, frequency map was prepared for a few dominant species. In order to achieve elevation map, the study area was mapped with Nivo camera. Based on the correlation of environmental factors obtained, the regression model of prediction for a few species was obtained. Maps of environmental factors, elevation, slope, slope direction, the percentage of organic matter, the percentage of fine-grained sediments, the distance from the bottom tidal line, and data from two satellite bands of 1 and 6 of landst8 as inputs to this model were entered in ArcGIS software and the prediction map of the presence or absence for these species were prepared. The results of this model was evaluated by the Kappa statistic. The results of this test showed that this method will be an appropriate method for modelling of prediction for potential distribution of macrobenthic species.

This study aimed to screen Thais savignyi whole body extracts for antibacterial activity against clinical isolates of some human pathogenic bacteria and analyze its biochemical compounds, including carbohydrate, proteins, alkaloids, cholesterol, unsaturated fatty acids, as well as functional groups and elements.
Well agar diffusion was used for screening of acetone and methanol extracts against clinical isolates of E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus. Biuret and SDS-PAGE methods were applied for quantitative and qualitative protein evaluation. Anthrone method was used for quantitative and qualitative analysis of carbohydrates. Wagner and Mayer's reagents were employed for alkaloid screening. The Liebermann-Burchard test was performed for the detection of cholesterol, infrared for identifying functional groups, and Dumas method for elemental analysis.
Acetone and methanol crude extracts at 0.2 mg/mL concentration inhibited the growth of all the test bacteria; however, the methanol extract was more effective than the acetone extract. The maximum zone of inhibition of the methanol extract was observed against B. cereus (16 mm). Minimal inhibitory concentration of the most effective fraction ranged between 12.5 and 100 µg/mL. Elemental analysis of the bioactive fraction showed 41.55% carbon, 9.49% hydrogen, 6.13% nitrogen, and 1.64% sulfur. IR spectra confirmed the presence of aliphatic, alkenes, secondary amines, and disulfide groups in the most effective fraction of methanol extract of Thais savignyi. Carbohydrate and protein analysis revealed 4.5% carbohydrate and 9% protein. SDS-PAGE disclosed 5 separate bands with 70, 53, 41, 30, and 22 kilodaltons. Wagner and Mayer test showed the presence of alkaloids; mercuric and iodine solutions indicated the presence of unsaturated fatty acids; cholesterol was detected by Liebermann-Burchard reaction and Salkowski test.
The findings of this study suggest that Thais savignyi has antibacterial potential and can be recommended as a source of bioactive compounds of medicinal value.

Worldwide, the genus Metopograpsus consists of six species . Metopograpsus thukuhar and Metopograpsus messor are common species belong to the genus that found in the Persian Gulf.. These two species are morphologically very similar to each other; as a result, their recognizing is morphologically very confusing. The existence of cryptic and sibiling species are common in marine crustaceans. The aim of this study was to evaluate whether the six morophotypes (A-E) from Metopograpsus are genetically differentiated or not, and thus, it used molecular data (mitochondrial COI) with emphasis on ultrastructure of the male first gonopod to explore evolutionary relationships in this genus. The results of present study showed that the nucleotide sequence of the mitochondrial gene fragment (COI) is not identical in all samples examined and from these 6 morphotypes ,Metopograpsus sp.PGE species was more different with other morphotypes and it was placed in a separate clade. Ultrastructure Study of the apical part of the first male gonopods showed that there are differences in the apical part of 6 color morphtypes. what was obtained from this study showed that It is very important to investigate the first male gonopod based on the COI gene in separation of species since, identification of species is difficult for many similarities morphology.

Species identification is always important. Records of sea urchins and sand dollars species ýý(Echinodermata, Echinoidea) is given from Iranian waters. Nine Species of Echinoderms were ýidentified through the study. The species identification was made using morphological ýcharacteristics and review of checklist key. Nine species were identified here, including ýEchinometra mathaei, Prionocidaris baculosa, Temnopleurus toreumaticus, Echinothrix ýcalamaris, Clypeaster humilis, Echinodiscus auritus, Diadema setosum, Diadema savignyi and ýParasalenia gratiosa of which three species namely Echinothrix calamaris, Diadema savignyi ýand Parasalenia gratiosa were new records to Persian Gulf.ý

128 kilometers in the city of Ahwaz and khoramshahr in southwestern khouzestan is located. Karoon River before reaching the Persian Gulf, in khoramshahr Divided two branches Bahmanshyr and Hafar. In to the importance of Hafar River Hydrology situation that fresh water and salt water are important Macrobenthic it will. In this study selected 10 stations within the study scope. Sampling, March 86 started and ended in September of 87. Samples by Grab Van Vienn (025/0 m2) in both warm and cold season and once in each season was done. To the 3 samples from each station to identify benthic sediment and one sample for Grain sediment Analysis (GSA) and Total organic materials (Tom) were harvested. Physicochemical parameters of the DO, salinity, PH and temperature were analyzed.Macrobenthic between groups identified the most abundant Insect group and sex Nereis sp.Identified Macrobenthic groups consist of Polychaete 65.19%,Gastropoda 29.65%,Bivalvia 4.97% and Insecta 0.18% respectively.In stations that the amount of material dissolved was high,macrobenthics was significantly redused.in station 1(saboonsazi factory)and residual tissues silt_clay and sand was fine to their numbers.most the benthic community in the river downstream stations were observed in the amount of organic matter in sediments of this stations is less.In general, sandy sediment and low organic matter sediment contain more were the most community.

During summer and winter 2014, forty sediment samples were taken from Bahrekan Bay region using VanVeen grab (0.025 m2 area). According to the results, 59 species and 52 Genus were identified. There were a positive correlation between %TOM, %Silt and Clay fractions and macrofaunal assemblages. The dominant species in all studied stations were Cerithium sp., Cerithidea cingulata, Pseudonoba sp.2, Tornatina persiana and Paraprionospio pinnata. Grain size analysis showed that the substrate of study area was muddy. The highest %TOM ranged from 6±0.15 to 20.76±0.33 in winter. The results showed that the positive correlation between %TOM and %Silt and Clay were r=0.79 in the summer and r=0.48 in the winter. The highest and lowest number of individuals of macrofauna were counted in summer (2038 ind. / 0.025 m2) and winter (1722 ind. / 0.025 m2) respectively. During this study, Bivalves were the dominant group (%39.14) followed by Gastropoda (%38.47), Polychaeta (%19.23), Crustacea (%2.92), Scaphopoda (%0.17), Echinodermata (%0.07) and Soft Corals (%0.04). The comparison of H′ values with Welch model showed that study area is in the moderate level of this model with low species diversity.

Calanoid, cyclopoid, harpacticoid and poecilostomatoid copepods were investigated over the year at five stations in the Chabahar Bay, Oman Sea. This area is under the influence of the Indian Ocean seasonal monsoons. The samples were collected using vertical plankton tows with 100 µm mesh nets. Copepods were identified into 20 genera and 59 species. Calanoid formed about 15% to 62% and cyclopoid 26% to 39% of total copepod abundance. Harpacticoid constituted about 6% in South West (SW)-monsoon and flourished well in pre (SW)-monsoon, formed 46% of copepod abundance. Poecilostomatoid accounted for approximately 5% to 13% of the total copepods. The most dominant species were Temora turbinata, Paracalanus elegans, Oithona nana and Euterpina acutifrons. The results showed that the species composition and distribution of copepods differed between the monsoon seasons, due to changes in hydrographic conditions. Furthermore, high abundance of small-sized copepods observed in offshore stations.

Caspian Sea in Iran, particularly in the study of habitat as one of the most important water resources in the country and the largest brackish lake is of remarkable importance. The purpose of this research is to better understand the research community Khzrmy Myvbntyk Sea Ostracoda as environmental indicators suitable for assessing the environmental context are used. Geographical location between the coastal city of Nor to NOSHAHR is studied. This study sampled in two seasons (winter 1390 and spring 1391) along four transects, each with 4 stations (at depths of 20 and 5,10,15 mm) was performed using grab Van Vienna. Physical and chemical factors in the water near the seabed, including temperature, dissolved oxygen, pH and electrical conductivity were measured during sampling, sediment and other geological studies were conducted in a laboratory setting. Based on studies of the sediments in the area consist of fine sand, very fine sand, silt and clay were determined. Among the environmental factors, significant positive correlation between the abundance of Ostracoda with the amount of electrical conductivity of organic materials and Jude Law (P<0/05). In this study, Ostracoda 9 species belonging to 7 genera of 7 families were identified

Mercury concentrations in various tissues of Yellowfin seabream (Acanthopagrus latus) were determined in five creeks of Musa Estuary – (1) Zangi، (2) Jafari، (3) Petroshimi، (4) Ghazaleh، and (5) Majidieh. Tissue samples were digested in acid and their Hg concentrations were assayed by atom-absorption method. Generally، the order of Hg concentrations in creeks was: Majidieh ≈ Ghazaleh > Petroshimi ≈ Jafari > Zangi. High concentrations at Majidieh and Ghazaleh is due to the location of the these creeks at the end sections of Musa Estuary، less water exchange with the open sea، transport of pollutants by tidal currents، presences of oil export wharf and oil effusions، and probably appropriate condition for the more Methylation of mercury. Calculation of muscle-liver ratio also indicated that only the condition of Zangi creek is close to environmental static conditions. Finally the order of mercury accumulation in body tissues of Yellowfin seabream was liver > muscle > skin ≈ bone ≥ fin ≈ scale، indicating high accumulation capacity of liver and muscle compared to other tissues، probably due to developed vascularization، high percentage of water content، and biochemical and functional characteristics of these tissues. It is also found that by the increase of mercury pollution the difference between Hg accumulation in liver and muscle increased.

This study was done to determine the mercury concentration in the surficial sediments from the Musa Estuary. 5 creeks including Zangi, Jafari, Petroshimi, Ghazaleh and Majidieh were selected and a total number of 9 sediment samples were collected from each creak. Sampling was performed in November 2009. Mercury concentrations were measured by cold vapor atomic absorption spectrophotometer, after digesting of the samples. The mercury concentrations in the sediments ranged from 0.31 to 0.69 µg/g. The highest Hg contents were found in the Petroshimi estuary followed by Majidieh estaury, probably due to the effluent inputs from Bandar Imam Chloralkali petrochemical plant, oil spills and Navigation and shipping related activities. Regarding the contamination factor at regional level, the studied estauries are classified as a considerably polluted area, but at global scale, contamination factor shows low to moderate degree of pollution in them.

The 800 species of echinoids alive today, coupled with the wonderful fossil record, make the echinoids excellent candidates for a great variety of studies, from reproductive biology to evolution. The irregular echinoid Clypeaster Lamarck is locally common in Oligocene to Quaternary sedimentary deposits in the Caribbean region. Clypeaster, seen from the post-Eocene epoch. Clypeaster humilis; is such a class of Echinoidea that this species seen in the Persian Gulf but Iranian waters. This species resembles C. humilis (LESKE, 1778) a living species of the Persian Gulf in Arabia coastal and Red Sea but the present paper recorded from Hendorabi Island for the first time. The species is widely distributed in tidal and shallow waters of tropical and subtropical regions. Clypeaster humilis, ranging from the Persian Gulf, in depth of sandy-soft sediments to about 10-15 meters.

Content of mercury in hepatopancreas, muscle and exoskeleton of blue crab T. prymna from Musa estuary and their relationship with size of the organism and season were determined. Mean concentration of mercury in hepatopancreas, muscle and exoskeleton were 1.23, 0.61 and 0.41 µg/g dw, respectively. There was significant difference (p<0.05) in mercury levels depending on the sex with greater mercury contents in female crabs. Mean concentrations of mercury in tissues of crab during summer and winter varied and it was greater in summer than winter (0.94 and 0.75 µg/g dw, respectively).

Temporal and spatial variation of zooplankton abundance, composition and biomass were examined on the Chabahar Bay, Oman Sea. The Chabahar Bay, a subtropical and semi-enclosed bay, provides an ideal breeding ground for many fish and shellfish. Five stations were investigated along the Bay. This area is under the influence of the Indian Ocean seasonal monsoons. Zooplankton was collected with vertical plankton tows using 100 μm mesh nets. Copepods dominated the zooplankton community followed by larvacea, cladocera and chaetognatha. Fifteen taxa of zooplankton were identified. Oithona nana and Euterpina acutifrons were dominated in the whole year and Larvacea showed a bloom in Northeast Monsoon. A Two-way ANOVA indicated that there were differences in abundance and biomass between sampling periods and between stations were significant. The peak zooplankton abundance in NE Monsoon could be due to winter cooling, with entrainment of nutrients into the upper layer producing phytoplankton blooms. The decline of zooplankton abundance and biomass in South West Monsoon and post-monsoon could be explained by decrease in chlorophyll a concentrations. The present result showed the composition and distribution of zooplankton differed between the monsoon seasons, resulted from changes in hydrographic conditions.

The antioxidant activity, contents of total phenolics and flavonoids were quantified in the methanolic extracts of four Ulva species(U.clathrata,U.linza,U.flexuosa and U.intestinalis) grown at different parts of northern coasts of the Persian Gulf in south of Iran.The seaweeds were collected from Dayyer,Taheri and Northern Ouli coasts in April 2011. Methanolic extracts of the seaweeds were assessed for their antioxidant activity using DPPH radical scavenging assay and was performed in a microplate reader. All species exhibited a DPPH radical scavenging activity, and among the species, Ulva clathrata demonstrated greater antioxidant potential with a low IC50 (0.881 mg ml-1) in comparison with the other species. Also the highest phenolic content (5.08 mg GAE g-1) and flavonoid content (30.31 mg RE g-1) were observed in U.clathrata.The phenolic and flavonoid contents showed positive correlations with the DPPH radical scavenging activity (p<0.01) and negative correlations with IC50 (p<0.01).The results suggest that these edible green seaweeds possess antioxidant potential which could be considered for future applications in medicine, dietary supplements, cosmetics or food industries.