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  • Astara  (5)
  • Euphotic layer  (4)
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  • 1
    Publikationsdatum: 2021-05-19
    Beschreibung: This study was conducted to physico-chemical characteristics of water in the Iranian coastal of southern Caspian Sea during four seasons at 8 transects (Astra, Anzali, Sefidrud, Tonekabon, Nowshahr, Babolsar, Amirabad and Bandar Turkman) during 2009-2010. 480 samples were collected at different layers of water and then analyzed based on standard methods. Results showed that the mean of water temperature were 18.67±0.32 and 17.82±0.43 ◦C at the surface and euphotic layer, respectively. Minimum and maximum of water temperature were recorded in winter (6.40) and summertime (27.60). In addition, temperature gradient was ranged between 12 to 15 ◦C at 20 to 50 layers in 50 and 100m depths. Mean of salinity was 11.04±0.17 g/l at euphotic layer. Pearson correlation between temperature and salinity was positively significant. Therefore, maximum salinity was recorded in summer and minimum in winter. Mean of transparency (SD) in the present study was 4.35±0.21 m which compared to the pervious sampling period (2008) showed small decrease, but the mean of pH was observed 8.43±0.01 which was higher than the previous sampling period (2008). The mean of DO and DO% were observed 5.72±0.06 ml/l and 130±1 percent at euphotic layer during sampling period. The mean of DO% was recorded 104±5 at euphotic layer in 1996 (before introduction of Mnemeiopsis leidyi), but the study in the years 2004, 2008 and present (one decade after introduction of Mnemeiopsis leidyi) this value was registered higher than 120% at euphotic layer. This shows that trophic status of Caspian ecosystem shifted from oligotrophy (before introduction of Mnemeiopsis leidyi) to meso-eutrophy (after introduction of Mnemeiopsis leidyi). Annual concentration of inorganic nitrogen (DIN= NH4 +, NO2-, NO3-) has a fairly wide variation. Percentage of nitrogen components out of DIN were varied 9-98, 0.2-28.2 and 0.0-90.0 respectively. In this study, percentage of DIN was lower than 15% and organic nitrogen (DON) was higher than 80%. Overall, results showed that water temperature, salinity, transparency and DON were recorded lower than the previous study (2008), but DO, DO%, pH, NH4+, NO3- and DSi were higher than the previous sampling period. Inorganic phosphorous (DIP) and NO2- have not changed substantially. N/P ratio of Caspian Sea has a narrow range which order of magnificent lower than other seas. The results of the present study showed that Caspian ecosystem was nitrogen limitation before introduction of Mnemeiopsis leidyi, while it seems that after introduction of Mnemeiopsis leidyi the system has been shifted to the phosphorous limitation.
    Beschreibung: Iranian Fisheries Science Research Institute
    Beschreibung: Published
    Schlagwort(e): Physico-chemical parameters ; Nutrients ; Water ; Temperature ; Salinity ; Euphotic layer ; Sampling ; Mnemeiopsis leidyi ; Oligotrophy
    Repository-Name: AquaDocs
    Materialart: Report , Refereed
    Format: 104pp.
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  • 2
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25563 | 18721 | 2018-10-05 16:51:28 | 25563 | Iranian Fisheries Science Research Institute
    Publikationsdatum: 2021-07-16
    Beschreibung: In this study, the characteristics of physico-chemical parameters of water done in coastal part of the southern Caspian Sea during 2010-2011 (four seasons) in 8 transects (Astara, Anzali, Sefidrour, Tonkabon, Noshahr, Babolsar, Amirabad and Torkman). For measurement of water quality parameters, 480 samples were collected in different water layers by using of APHA standards methods. According to modeling and statistical methods was used multivariate for evaluation of factor analysis (MFA) in general groups and discriminant analysis (MDA) for spatial and temporal with water quality parameters. The statistical procedure of MFA was used for data reduction and finally six factors selected with about 80.48 percent of total variances related to them. The statistical procedures of MDA were used for the role of spatial and temporal of water quality parameters in different water layer. The function one gave eight parameters (pH, salinity, EC, DO, NO^3-, water temperature, NH^4+ and N^-total) affording more than 80, 67, 80, 77 and 71 % correct assignations (return to the same transects) in spatial analysis. In all transects during four seasons, function one gave five parameters (water temperature, salinity, EC, NO^2- and NH^4+) to afford 100, 100, 100, 97 and 97 % correct assignations in temporal analysis. The results showed that, the average amounts in light penetration layers during four seasons were for EC(15.04±0.18ms/cm), pH(8.38±0.01unit), salinity (10.31±0.16g/l), DO(5.67±0.09ml/l) and water temperature (18.28 ±0.72°C). The average amount of nutrients for parameters such as organic and inorganic phosphorus, total phosphorus, NO^2-, NO^3-, NH^4+, N^-Total and SiO_2 were 0.50±0.02, 0.32±0.01, 0.82±0.02, 1.76±0.10, 0.10±0.01, 1.51±0.10, 46.82±1.80 and 8.60±0.29µM, respectively. The average amounts in dark layers during four seasons were for EC (15.46±0.38ms/cm), pH (8.34±0.03unit), salinity (10.70±0.35g/l), DO (4.55±0.13ml/l) and water temperature (9.62 ±0.16°C). The average amount of nutrients for parameters such as organic and inorganic phosphorus, total phosphorus, NO^2-, NO^3-, NH^4+, N^-Total and SiO_2 were 0.54 ±0.05, 0.33 ±0.02, 0.87±0.06, 1.92±0.21 , 0.08± 0.01, 1.55±0.25, 45.10±3.25 and 10.05±0.62 µM, respectively. The average amounts of light penetration in all transects during four seasons 4.49±0.38 meters. The maximum light penetrations during spring, summer, fall and winter seasons were 9, 8, 8.20 and 7 meters, respectively. The maximum water temperatures in light and dark layers were 32.36 and 11.50°C. Also, the maximum differences about thermocline temperature during summer and fall seasons were 19.6°C and 10°C, respectively in southern part of Caspian Sea. Data in spatial analysis were not significant (p〉0.05), it means if add or removed any transect did not change occurred. But in temporal analysis were significant (p〈0.01), and it means no way remove any seasons for a research work on Caspian Sea in southern part. In those transects with 100m depth. Water temperature is only highly effective parameter between other parameters. In function 1 between 3 functions in transects with 100m depth water temperature with 60% variance was the main role and effective between different seasons in depth part were very high.
    Schlagwort(e): Aquaculture ; Iran ; Caspian Sea ; Astara ; Anzali ; Sefidrour ; Tonkabon ; Noshahr ; Babolsar ; Physico-chemical parameters ; Nutrient maters ; Sea water ; APHA ; pH ; Salinity ; Temperature ; Nutrients
    Repository-Name: AquaDocs
    Materialart: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 134
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  • 3
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25335 | 18721 | 2018-09-13 12:35:23 | 25335 | Iranian Fisheries Science Research Institute
    Publikationsdatum: 2021-07-16
    Beschreibung: This study was conducted to study of Hydrology, Hydrobiology and Environmental pollution in the southern of the Caspian Sea. 33 stations were selected from Astara (in the west) to Hassan gholi (in the east). In each station, sampling carried out at suface, 10, 20, 50 and 100m depths. Sampling was performed during four seasons in 2004. Sampling stations also divided into three regions, including west (from Astara to Ramsar), middle (from Ramsar to Sari) and east (from Amirabad to Hassengholi). The results showed that maximum of water temperature was 24 ?C at summer in the eastern region while the minimum of water temperature in winter season has been 9.7 ?c in the western region. The average of dissolved oxygen concontration in spring, summer, autumn and winter season were 6.9 , 6.6, 8.2 and 6.7 mg/l , respectively. The maximum value of salinity was observed in spring (13.55 ppt) and minmum value in winter (8.24 ppt). The average of total nitrogen concentration were season was 711, 884, 583 and 669 µg/l in spring, summer, autumn and winter repectively. The average of total phosphorus concentration was 27.9, 37.1 and 42.6 µg/l in spring, summer, autumn and winter, respectively. The average of dissolved silica concentration has varied from 167 to 923.6 µg/l. The five phyla of phytoplankton have identified. The most species diversity was observed in winter (70 species) but the low species diversity has obtained in autumn. The most phytoplankton population was in spring and summer seasons. The cell abundance of phytoplankton in different seasons was fluctuated from 3914*103 to 17337*103 ind/m^3. In addition, the phytoplankton biomas was varied 11.4 to 30.7 mg/l. Result showed that distribution of phytoplankton are varied at different areas, layer, seasons and stations. The average of cell abundance of zooplanktons was varied from 2023 to 12364 and/m^3 at different seasons. The mean of bioman varied from 9.40 to 43.48 mg/l. In this study, 17 species and one class of macrobenthos were identified. The frequency of Annelida and Biovalvia was higher than all macrobenthos. The average of macrobenthos was 1218±851 ind/m^2 and their biomass was 14±15 g/l. The average of PAHs concentration were 0.038, 0.028 and 0.21 mg/l in spring , summer and winter, respectively. The decending trend of heavy metal concentration were Fe〉Mn〉Zn〉Cr〉Pb〉Co〉Cd〉Cu at different seasons in 2004. The maximum concentrations of organochlorine pesticides (OCPs) components in three regions of sampling zone such as , -BHC (middle), β,-BHC (middle), DDT (east) and dieldrin (east part) were 88.3, 35.0, 74.3 & 79.1 g/l during spring, summer, fall and winter, respectively.
    Schlagwort(e): Ecology ; Iran ; Caspian Sea ; Astara ; Physo-chemical parameters ; Plankton ; Benthos ; Enviromental Pollutions ; Hydrology ; Hydrobiology ; Sampling ; Temperature ; Dissolved oxygen ; Dissolved silica ; Species ; Phytoplankton ; Biomass
    Repository-Name: AquaDocs
    Materialart: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 102
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  • 4
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25413 | 18721 | 2018-09-23 16:29:08 | 25413 | Iranian Fisheries Science Research Institute
    Publikationsdatum: 2021-07-16
    Beschreibung: This survey was carried out by R/V Gilan with a conical plankton net of 100 micron mesh by vertical hauls at 8 transect in the southern Caspian sea. Transects were located at Astara, Anzali, Sefid roud, Tonekabon, Noshahr, Babolsar, Amirabad and Torkman in depths of 5, 10,20,50and 100m. Samples were taken in 4 seasons (in each season 64 samples) in 2009. In this study 23 species formed the zooplankton community including 4 species of Copepoda, 8 species of Rotatoria, 2 species of Protozoa and 8 species of Cladocera. The meroplankton blonged to 2 species of Balanus sp and Lamellibranchiata larvae. The annual results revealed that the maximum abundance of Copepoda were 3612±4839 ind/m^3 and 35/75±42/81 mg/m^3 in summer and decreased gradually since autumn and reached to minimum value in winter. The maximum abundance of Cladocera was 300± 383 ind/m^3 in spring and reached to less than 4 ind/m^3 in summer and autumn. The Rotatoria had high population (3775± 8632 ind/m^3) in winter which consisted the zooplankton population with Copepoda. The Protozoa had no efficient role in zooplankton population of Caspian sea during the year. The zooplankton population was affected by Meroplankton and Lamellibranchiata larvae in spring and winter. The Copepoda contributed in zooplankton population only in summer and autumn. The maximum zooplankton abundance and biomass were in 5m depth which included 10209±8352 ind/m^3 and 43.56±26.08mg/m^3 in spring, 8545±7127 ind/m^3 and 73.59±56.65 mg/m3 in summer (10 m depth), 8427±6711 ind/m^3 and 43.15± 29.59 mg/m3 in autumn and 24426±26975 ind/m^3 and 334.25±392.21 mg/. m3 in winter which decresed from surface to depth. The maximum abundance and biomass of zooplankton were 5119±6018 ind/m^3 in east and 28.59±24.79 mg/m^3 in central area in spring, 6628±7117 ind/m^3 in west area and 50.73±59.52 mg/m^3 in central area in summer, 5248±5489 ind/m^3 and 31/16 ±31/22 mg/ m^3 in west area in autumn and 11588±16191 ind/m^3 and 131.02±193.61 mg/ m^3 in west area in winter. The annual statistical analysis reveals that there is significant difference between Copepoda and Cirripedia population among seasons, sampling stations, depth and sampling layer (Kruskalwallis test, p〈0.05) and the total zooplankton populatin had no significant difference only between seasons (Kruskal-wallis test, p〉0.05). The Cladocera, Lamellibranchiata larvae and the Rotatoria had significant difference between seasons only (Kruskal-wallis test, p〈0.01).
    Schlagwort(e): Ecology ; Iran ; Caspian Sea ; Astara ; Anzali ; Tonekabon ; Noshahr ; Babolsar ; Zooplankton ; Copepoda ; Meroplankton ; Survey ; Plankton ; Samples ; Species ; Cladocera ; Meroplankton ; Balanus sp. ; Lamellibranchiata ; Larvae
    Repository-Name: AquaDocs
    Materialart: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 123
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  • 5
    Publikationsdatum: 2021-07-16
    Beschreibung: The Sampling of macrobenthic communities in southeastern Caspian Sea, Iranian coast, were investigated seasonally from April to March 2012. Sampling was carried out at 8 transect as named Astara, Badar Anzali, Sefied rood, Tonekaboon, Nooshahr, Babolsar, Amirabad, Gomishan.In each transect were choice 8 stations at 5m, 10m, 20m, 50m, 100m depths respectively. Samples were taken in triplet with a 0.1m^² van Veen grab.Totally 28 macrofaunal species belonging to 10 families were identified as gamaridae (9species), corophidae (3species),psudocumidae(8 species), amphartidae (2species), balanidae, chironomidae, cardidae scorbicolaridae, nereidae, sponoidae, each one species. Polychaetes were dominated, representing 72.5% of the whole fauna while while (equal 62.4% of total abundance and 5/1%biomass) were belong to Streblospio spp. from Spionidae family. Cerastoderma lamarcki belong to bivavia consist of 2/3% total macobethos abundance and 73% biomass. Total abundance of macrobenthos of middle area were higher than east and west area in southern Caspian Sea. Average benthic population density (no/m^2) with (SE) was 4581(444 ). The benthic biomass (mg/m^2) with an overall mean of 12. 125(02). Spatial and temporal variations of benthos. In the present study showed, maximum abundance Macrobenthos 17855(5543) no/m^2) were recorded in 20 meter depths at Nooshahr trancect , while minimum 841(109 )in 10 meter depths at Amirabad trancect p〈0.05. Maximum biomass 135.10(126) g/m^2 were obtained at 10m depths in Astara minimum 0.51(0.4) ) g/m^2 at 5m depths in Nooshahr transect . maximum were obtained in winter and minimum in summer Number of species varied 3 to 18 , Generally, minimum species diversity were obtained at 20 m depth in Tonekabon transects and the maximum value was observed at 100 m depth of sefeidrood variations physicochemical factors were between salinity 12.5to12.9ppt ,temperature 8-19˚c and PH 8.1 dissolve oxygen 69-101mg/li. Total secondary production calculated, according ,104/996g AFDW/m^2/yr.Maximum were recorded in 10meter depth (30/381AFDW/m^2/yr) and minimum at 50 meter depth(11/007g AFDW/m^2/yr) respectively. Average total organic matter were 3/18 percent in sample periods. Percent of total organic matter (TOM) were low in 5 and 10 m depths and increased toward offshore depths. TOM percent was 1/67(0.11 ) at 5 m depth and increased to 4/38(0.13 )in 100 m depth. Average total silt &clay were 68/63(2.97) percent in sample periods. Positive significant relation was between silt &clay and total organic matter. Macrobenthos community reduce in high silt clay and high sandy contents. Due to increase of streptolosbio.spp, monitoring program for understanding effect of this organism on ecosystem and on fish feeding is necessary.
    Schlagwort(e): Ecology ; Iran ; Caspian Sea ; Astara ; Badar Anzali ; Tonekabon ; Macrobenthos ; Diversity ; Distribution ; Abundance ; Biomass ; Secondary production ; Species ; Gamaridae ; Corophidae ; Psudocumidae ; Amphartidae ; Balanidae ; Chironomidae ; Cardidae ; Scorbicolaridae ; Nereidae ; Sponoidae ; Salinity ; Temperature ; Streptolosbio.spp
    Repository-Name: AquaDocs
    Materialart: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 70
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  • 6
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25347 | 18721 | 2018-09-13 13:02:23 | 25347 | Iranian Fisheries Science Research Institute
    Publikationsdatum: 2021-07-16
    Beschreibung: In order to determine the impact of the new invasive ctenophore (Mnemiopsis leidyi) of the Caspian Sea, it is needed to monitor the temporal and spatial distribution as well as seasonal biomass fluctuation of this animal. At the present study, sampling was conducted in 8 transects such as Astara, Anzali, sephidroud, Tonekabon Nowshar, Babulsar, Amirabad and Bandar Torkaman. Each transect had four stations located at the points off the shore where the bottom depth was 5, 10, 20 , 50 and 100m, respectively. Ctenophore samples were collected with planktonic net and simultaneously some morphometric characteristics such as weight, length, abundance and biomass were measured. Statistical analysis was done based on the averages of year, season, location, depth and size of the M. leidyi. In 2008, mean abundance and biomass of M. leidyi were recorded 63±7 ind.m^3 and 7.70±2.34 g.m^3, respectively. M. leidyi abundance and biomass were ranged of 0-639 ind.m^3 and 0-158 g.m^3, respectively. The maximum seasonal average of abundance was 150 ± 17 ind.m^3 while the maximum biomass was 26.59± 4.61.m^3 in summer. There is a significant different between abundance and biomass in summer and autumn, respectively (p〈0.05). Comb jelly length in autumn was smaller than in summer. Minimum M. leidyi abundance was observed in spring (4.0±0.7ind.m^3) and winter (6±2ind.m^3). The lowest average of seasonal biomass was observed in winter (0.50±0.07 g.m^3). The maximum of M. leidyi biomass was recorded at the depth 5m of Anzali in summer 2008 with 639 ind.m^3 and 158 g.m^3, respectively. There was not significant different between abundance and biomass in various transects (p〉0.05). The results showed that the highest abundance and biomass coincide to photic zone (≤ 20 m in depth) in which there is a significant different between photic zone and various layer (p〈0.05). The maximum ctenophore size was recorded 55 mm in 2006 and 60 mm in 2007, in which it was 50 mm in 2008. The data of M. leidyi from 2001 to 2008 indicated that abundance and biomass of comb jelly decrease in trend. Therefore, the results showed that the M. leidyi is a superficial and littoral species in the southern Caspian Sea.
    Schlagwort(e): Ecology ; Iran ; Caspian Sea ; Astara ; Anzali ; Tonekabon ; Nowshar ; Bandar Torkaman ; Abundance ; Biomass ; Mnemiopsis leidyi ; Fluctuation ; Sampling ; Ctenophore ; Plankton ; Morphometric ; M.leidyi ; Species
    Repository-Name: AquaDocs
    Materialart: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 55
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  • 7
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25387 | 18721 | 2018-09-20 11:19:25 | 25387 | Iranian Fisheries Science Research Institute
    Publikationsdatum: 2021-07-16
    Beschreibung: This study was conducted to physico-chemical characteristics of water in the Iranian coastal of southern Caspian Sea during four seasons at 8 transects (Astra, Anzali, Sefidrud, Tonekabon, Nowshahr, Babolsar, Amirabad and Bandar Turkman) during 2009-2010. 480 samples were collected at different layers of water and then analyzed based on standard methods. Results showed that the mean of water temperature were 18.67±0.32 and 17.82±0.43 ◦C at the surface and euphotic layer, respectively. Minimum and maximum of water temperature were recorded in winter (6.40) and summertime (27.60). In addition, temperature gradient was ranged between 12 to 15 ◦C at 20 to 50 layers in 50 and 100m depths. Mean of salinity was 11.04±0.17 g/l at euphotic layer. Pearson correlation between temperature and salinity was positively significant. Therefore, maximum salinity was recorded in summer and minimum in winter. Mean of transparency (SD) in the present study was 4.35±0.21 m which compared to the pervious sampling period (2008) showed small decrease, but the mean of pH was observed 8.43±0.01 which was higher than the previous sampling period (2008). The mean of DO and DO% were observed 5.72±0.06 ml/l and 130±1 percent at euphotic layer during sampling period. The mean of DO% was recorded 104±5 at euphotic layer in 1996 (before introduction of Mnemeiopsis leidyi), but the study in the years 2004, 2008 and present (one decade after introduction of Mnemeiopsis leidyi) this value was registered higher than 120% at euphotic layer. This shows that trophic status of Caspian ecosystem shifted from oligotrophy (before introduction of Mnemeiopsis leidyi) to meso-eutrophy (after introduction of Mnemiopsis leidyi). Annual concentration of inorganic nitrogen (DIN= NH^4 +, NO^2-, NO^3-) has a fairly wide variation. Percentage of nitrogen components out of DIN were varied 9-98, 0.2-28.2 and 0.0-90.0 respectively. In this study, percentage of DIN was lower than 15% and organic nitrogen (DON) was higher than 80%. Overall, results showed that water temperature, salinity, transparency and DON were recorded lower than the previous study (2008), but DO, DO%, pH, NH^4+, NO^3- and DSi were higher than the previous sampling period. Inorganic phosphorous (DIP) and NO^2- have not changed substantially. N/P ratio of Caspian Sea has a narrow range which order of magnificent lower than other seas. The results of the present study showed that Caspian ecosystem was nitrogen limitation before introduction of Mnemiopsis leidyi, while it seems that after introduction of Mnemiopsis leidyi the system has been shifted to the phosphorous limitation.
    Schlagwort(e): Ecology ; Iran ; Caspian Sea ; Astra ; Anzali ; Tonekabon ; Nowshahr ; Babolsar ; Sefidrud River ; Physico-chemical parameters ; Nutrients ; Water ; Temperature ; Salinity ; Euphotic layer ; Sampling ; Mnemeiopsis leidyi ; Oligotrophy
    Repository-Name: AquaDocs
    Materialart: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 104
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  • 8
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    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25382 | 18721 | 2018-09-14 07:50:45 | 25382 | Iranian Fisheries Science Research Institute
    Publikationsdatum: 2021-07-16
    Beschreibung: The Study of phytoplankton in the Caspian Sea was substantially started in the 1990s with the aim to produce and record data. phytoplankton study in this area became more important because of the occurance of some ecological events in recent years (such as bloom and arrival invader species). The study was seasonally conducted in western (Giulan province) to eastern coast (Golestan province) at 8 transects (Astra, Anzali, Sefidrud, Tonekabon, Nowshahr, Babolsar, Amirabad and Bandar Turkman) from inshore (5 m depth) to offshore (100 m). 476 samples were collected to study quantification and qualification of phytoplankton in 2009-2010. Results showed that 195 species of phytoplankton were identified in 8 phylums which were classified to Bacillariophyta (81 species), Pyrrophyta (33 species), Cyanophyta (28 species), Chlorophyta (38 species), Euglenophyt (11 species), Xantophyta (1 species), Chrysophyta (2 species) and Haptophyta (1 species). Abundance and biomass of phytoplankton were significantly different between euphotic layer (0 to 20m depths) and aphotic layer (50 to 100m depths) (p〈0.05). Minimum and maximum of phytoplankton abundance at euphotic layer were observed in spring (49±14 million/m^3) and winter (289±10 million/m^3), respectively. Minimum and maximum of phytoplankton biomass at euphotic layer were observed in summer (188±56 mg/m^3) and winter (1323±20 mg/m^3), respectively. In addition, minimum and maximum of phytoplankton abundance at euphotic layer were observed in western region (100±11 million/m^3) and central region (186±27 million/m^3), respectively. Mean of phytoplankton biomass at euphotic layer of western and central regions (584±74 mg/m^3) was higher than eastern region (473±19 mg/m^3). Abundance and biomass of phytoplankton were high in inshore (10m depth) in all seasons and decrease to offshore (100m depth), but the difference of abundance and biomass was not significant between inshore and offshore (p〉0.05). In spring, Bacillariophyta and Pyrrophyta with 40% and 29% of total abundance were dominant phylum at euphotic layer. In fall, Bacillariophyta (57% of total abundance) and Cyanophyta (28% of total abundance) were the first and second dominant phyla. While in summer and winter the predominant phyla was made by Cyanophyta (92% of total abundance) and Bacillariophyta (94% of total abundance) respectively. Species richness in western, central and eastern regions was 119, 141 and 147 respectively. Shannon index was 2.39 and 2.04 at euphotic layer and below photic layer, respectively. Shannon and evenness indices in eastern region was lower than western and central regions. Meanwhile, Shannon index in spring and autmn (2.50 and 2.39) was higher than summer and winter (0.21 and 0.36). In photic layer, dominant species were Stephanodiscus hantzschii Chrysochromulina sp. and Exuviaella cordata in spring. While Oscillatoria sp. was the predominant species in summer. In fall, dominant species contained Thalassionema nitzschioides and Oscillatoria sp. Finally, Pseudonitzschia seriata and Cerataulina pelagica made the most abundance species in winter. The dominant species in the below phoyic layer was very similar to photic layer. The mean abundance of Pseudonitzschia seriata , Oscillatoria sp. and Dactyliosolen fragilissima was higher than other species in all regions of study area (west, middle and east). Seasonal succession of dominant species were under the influence of natural factors such as sunlight, heat, river currents, wind and vertical mixing of water. However it seems that the invasion of ctenophore into Caspian Sea (with change in nutrient levels and decline of phytoplankton predator) and also human activities (i.e. water balance of ships and discharge of sewage) are severely impact on seasonal dominant species, pattern of species composition and relative abundance of species. These changes mainly accompany with appearance of new and harmful species (with the ability of severe proliferation) and displacement of native and dwell species.
    Schlagwort(e): Ecology ; Iran ; Caspian Sea ; Giulan province ; Golestan province ; Phytoplankton ; Diversity ; Abundance ; Biomass ; Survey ; Species ; Phylum ; Bacillariophyta ; Pyrrophyta ; Cyanophyta ; Chlorophyta ; Euglenophyt ; Xantophyta ; Chrysophyta ; Haptophyta ; Euphotic layer
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    Materialart: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 122
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  • 9
    Publikationsdatum: 2021-05-19
    Beschreibung: The Study of phytoplankton in the Caspian Sea was substantially started in the 1990s with the aim to produce and record data. phytoplankton study in this area became more important because of the occurance of some ecological events in recent years (such as bloom and arrival invader species). The study was seasonally conducted in western (Giulan province) to eastern coast (Golestan province) at 8 transects (Astra, Anzali, Sefidrud, Tonekabon, Nowshahr, Babolsar, Amirabad and Bandar Turkman) from inshore (5 m depth) to offshore (100 m). 476 samples were collected to study quantification and qualification of phytoplankton in 2009-2010. Results showed that 195 species of phytoplankton were identified in 8 phylums which were classified to Bacillariophyta (81 species), Pyrrophyta (33 species), Cyanophyta (28 species), Chlorophyta (38 species), Euglenophyt (11 species), Xantophyta (1 species), Chrysophyta (2 species) and Haptophyta (1 species). Abundance and biomass of phytoplankton were significantly different between euphotic layer (0 to 20m depths) and aphotic layer (50 to 100m depths) (p〈0.05). Minimum and maximum of phytoplankton abundance at euphotic layer were observed in spring (49±14 million/m3) and winter (289±10 million/m3), respectively. Minimum and maximum of phytoplankton biomass at euphotic layer were observed in summer (188±56 mg/m3) and winter (1323±20 mg/m3), respectively. In addition, minimum and maximum of phytoplankton abundance at euphotic layer were observed in western region (100±11 million/m3) and central region (186±27 million/m3), respectively. Mean of phytoplankton biomass at euphotic layer of western and central regions (584±74 mg/m3) was higher than eastern region (473±19 mg/m3). Abundance and biomass of phytoplankton were high in inshore (10m depth) in all seasons and decrease to offshore (100m depth), but the difference of abundance and biomass was not significant between inshore and offshore (p〉0.05). In spring, Bacillariophyta and Pyrrophyta with 40% and 29% of total abundance were dominant phylum at euphotic layer. In fall, Bacillariophyta (57% of total abundance) and Cyanophyta (28% of total abundance) were the first and second dominant phyla. While in summer and winter the predominant phyla was made by Cyanophyta (92% of total abundance) and Bacillariophyta (94% of total abundance) respectively. Species richness in western, central and eastern regions was 119, 141 and 147 respectively. Shannon index was 2.39 and 2.04 at euphotic layer and below photic layer, respectively. Shannon and evenness indices in eastern region was lower than western and central regions. Meanwhile, Shannon index in spring and autmn (2.50 and 2.39) was higher than summer and winter (0.21 and 0.36). In photic layer, dominant species were Stephanodiscus hantzschii Chrysochromulina sp. and Exuviaella cordata in spring. While Oscillatoria sp. was the predominant species in summer. In fall, dominant species contained Thalassionema nitzschioides and Oscillatoria sp. Finally, Pseudonitzschia seriata and Cerataulina pelagica made the most abundance species in winter. The dominant species in the below phoyic layer was very similar to photic layer. The mean abundance of Pseudonitzschia seriata , Oscillatoria sp. and Dactyliosolen fragilissima was higher than other species in all regions of study area (west, middle and east). Seasonal succession of dominant species were under the influence of natural factors such as sunlight, heat, river currents, wind and vertical mixing of water. However it seems that the invasion of ctenophore into Caspian Sea (with change in nutrient levels and decline of phytoplankton predator) and also human activities (i.e. water balance of ships and discharge of sewage) are severely impact on seasonal dominant species, pattern of species composition and relative abundance of species. These changes mainly accompany with appearance of new and harmful species (with the ability of severe proliferation) and displacement of native and dwell species.
    Beschreibung: Iranian Fisheries Science Research Institute
    Beschreibung: Published
    Schlagwort(e): Ecological ; Phytoplankton ; Diversity ; Abundance ; Biomass ; Survey ; Species ; Phylum ; Bacillariophyta ; Pyrrophyta ; Cyanophyta ; Chlorophyta ; Euglenophyt ; Xantophyta ; Chrysophyta ; Haptophyta ; Euphotic layer
    Repository-Name: AquaDocs
    Materialart: Report , Refereed
    Format: 122pp.
    Standort Signatur Erwartet Verfügbarkeit
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