906 resultados para Fresh water
Resumo:
In this research, 9 species of local and introduced fishes of the Zayandehroud River in Esfahan province (in the Sarmatian region belonging to the large paleoarctic fauna) in 6 seasons (winter 2003, spring, summer, autumn and winter 2004 and summer 2005) were parasitologically studied. The local fishes included alburnoides bipunctatus, Alburnus maculatus, Aphanius vladykovi, Capoeta aculeata & Capoeta damascina & the introduced fishes included Aristichthys nobilis, Carassius auratus, Ctenopharyngodon idella and Cyprinus carpio. Upon being hunted, the fishes were transferred alive to Esfahan Aquatics Breeding Center and physiologically studied after the determination of their species and genus by identification keys Berg (30), Coad (31), Saadati (51), Abdoli (20) and Holchic (38). 32 species of parasites were totally identified as follows: 6 Protozoan species including Ichthyophthirius multifiliis, 5 Trichodina species, 2 Myxobolus species including Myxobolus cristatus & Myxobolus saidovi, 16 monogenea species including Dactylogyrus alatus. D. anchorutus, D. baueri, D. chalcalburni, D. chramuli, D. extensus, D. gracilis, D. lamellatus, D. lenkorani and D. pukher, 4 Dactylogyrus spp. 2 Gyrodactylus species, 1 species of Digenea, Diplostomum spthaceum, 4 species of Cestoda including Bothriocephallus gowkongensis, khawia armeniaca, Ligulaintestinalis. Caryophyllaeus sp. 1 Acanthocephala: Acanthocephalo rhynchoides cholodkowsky, 2 species of the crustaceans including the mature & copepodian stages of Lernaea cyprinacea & 1 sp of the genus Lamproglena. Out of all the 166 pcs of the fishes hunted in this research, 127 fishes (76.5%) were infected, and 39 fishes (23.50%) were not infected. In the fishes studied, having 14 of 32 species of the parasites identified, Capoeta aculeata displayed the most variety of infection, and having only 1 sp of the parasites. Aristichthys nobilis displayed the least variety of infection. The new findings of the research will follow: Myxobolus saidovi sp is reported for the 1st time from Iran's fresh water fishes, Alburnus maculatus and Capoeta aculeata are new hosts for M. saidovi and M. cristatus, respectively. Regarding monogenea Capoeta damascina & C. aculeata were reported as the new hosts for parasite D. pukher. The presence of D. pukher the infection of Capoeta aculeata with D. chramuli, D. lenkorani and D. gracilis in the Zayandehroud river were the 1st report. Regarding the Cestodea, Bothriocephalus gowkongensis was reported to be hosted by Aphanius Vladykovi for the 1St time in Iran.
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Alestes baremoze (Joannis, 1835), locally known as Angara in Uganda, is native to fresh water systems in Africa, thriving well in both lacustrine and riverine conditions. It is part of the routine diets of families in northern Uganda, South Sudan, the Sudan and the Democratic Republic of Congo. The objective of this study was to determine the proximate composition and mineral contents of A. baremoze fillets according to fish size. The mineral contents of A. baremoze from Lake Albert were analysed using standard procedures. The fish samples were categorised into three size-groups; <1 kg (880–990g), 1-1.5 kg and 1.6-2.5 kg. On wet weight basis, there were no significant differences (p>0.05) in crude protein and ash content among the different fish sizes. However, there were significant differences (p<0.05) in crude fat, carbohydrate, gross energy and vitamin A. Crude fat (0.35%), carbohydrate (0.37%) and gross energy (597.6 Kcal/100 g) were significantly higher in medium sized fish (1 to 1.5 kg) compared with the larger fish category. Vitamin A contents of different fish sizes ranged from 55.1 to75.3 μg RAE/100g. The contents of magnesium and iron were highest in sizes <1 kg (5.34 mg/100 g) and (3.58 mg/100 g), respectively. It was observed that potassium content (339.33 mg/100 g) and calcium (29.75 mg/100 g) were significantly higher (p<0.05) in fish >1.5 kg. These findings suggest that taste, freshness and other related external appearances should not be the only factors to be considered in making choice for marketing and consumption of Alestes baremoze.
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The hydrodynamics and hydrochemistry of salt and fresh water from solid rock aquifer systems in the Pyrmont area are described and interpreted on the basis of recent investigations including geoelectrics, isotope hydrology, soil air analysis. Theories on the source of the springs in this area are developed, which explain the different compositions of the springs and make it possible to protect them. Data from new and re-interpretated drill holes, borehole logs and outcrops suggest a revision of the geological structure of the Pyrmont dome. Bad Pyrmont is situated on a wide dome of Triassic rocks in the southern part of the Lower Saxony uplands. Inversion of the relief has caused the development of an erosional basin surrounded by prominent ridges. Deep faults developed at the crest of the dome as this part of the structure was subjected to the strongest tectonic stress. Subrosion of the Zechstein salts in the western part of the dome has caused the main salt bed to wedge out below the western part of the dome along a N-S striking structure; this structure is refered to as the „Salzhang“ (salt slope). West of the „Salzhang“, where subrosion has removed the salt bed that prevents gas rising from below, carbon dioxide of deep volcanic origin can now rise to the surface. Hydraulic cross sections illustrate the presence of extensive and deep-seated groundwater flow within the entire Pyrmont dome. While groundwater flow is directed vertically downwards in the ridges surrounding the dome, centripetal horizontal flow predominates the intermediate area. In the central part of the dome, groundwater rises to join the River Emmer, which is the main receiving water course in the central part of the eroded basin. The depth of the saltwater/freshwater interface is determinated by the weight of the superimposed freshwater body. Hydrochemical cross sections show the shape and position of the interface and document a certain degree of hydrochemical zonation of the gently mineralized fresh water. Genetic relationships between the two main water types and the hydrochemical zones of the freshwater body are discussed. The knowledge of the hydrogeological relationship in the Bad Pyrmont aquifer systems permits a spatially narrow coexistence of wells withdrawing groundwater for different purposes (medicinal, mineral, drinking and industrial water).
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The incidence of toxic cyanobacterial blooms is one of the important consequences of eutrophication in aquatic ecosystems. It is a very common phenomenon in reservoirs and shrimp ponds in the State of Rio Grande do Norte (RN), Brazil. Cyanobacterias produce toxins which can affect aquatic organisms and men trough the food chain. Aiming to contribute to the studies of cyanobacterias in RN, we propose: a) to evaluate the toxicity of isolated cyanobacterias in important fresh-water environments; and b) to verify the effects of both natural and cultured blooms occurred in reservoirs for human supply and in the cladoceran Ceriodaphnia silvestrii. This study was carried out using samples of natural blooms occurred between March and October of 2004 in Gargalheiras Dam (08º L e 39º W), in July of 2004 in Armando Ribeiro Gonçalves Dam (06o S e 37o W) and in commercial shrimp ponds (Litopenaeus vannamei) located in fresh-water environments. The samples were collected with plankton net (20µm.) for identification, isolation and obtaining of phytoplanktonic biomass for liophilization and later toxicity bioassays. The toxicity of cultured samples and natural blooms was investigated through bioassays in Swiss mice. Quantification of cyanobacteria in samples was conducted following the Ütermol method, with 300mL samples fixed with lugol. The toxicity test with Ceriodaphnia silvestrii followed ABNT, 2001 recommendations, and were accomplished with natural hepatotoxic bloom s samples and cultured samples of both non-toxic and neurotoxic C. raciborskii. In this test, five newborns, aged between 6 and 24 hours, were exposed to different concentrations (0 a 800 mg.L-1) of crude cyanobacterial extracts during 24 and 48 hours. Three replicates were used per treatment. The pH, temperature and dissolved oxygen at the beginning and after 24 and 48hours from the test were measured. We estimated the CL50 through the Trimmed Spearman-Karber method. The blooms were constituted by Microcystis panniformis, M. aeruginosa, Anabaena circinalis, Cylindrospermopsis raciborskii and Planktothrix agardhii, producers of mycrocistin-LR confirmed with HPLC analysis. Samples of hepatotoxic blooms registered toxinogenic potential for C. silvestrii, with CL50-24h value of 47.48 mg.L-1 and CL5048h of 38.15 mg.L-1 for GARG samples in march/2005; CL50-24h of 113,13 mg.L-1 and CL5048h of 88,24 mg.L-1 for ARG July/2004; CL50-24h of 300.39 mg.L-1 and CL50-48h of 149.89 mg.L-1 for GARG October/2005. For cultured samples, values of CL50-24h and CL50-48h for C. raciborskii toxic strains were 228.05 and 120.28 mg.L-1, respectively. There was no mortality of C. silvestrii during the tests with non-toxic C. raciborskii strain. The toxicity test with C. silvestrii presented good sensitivity degree to cyanotoxins. The toxicity of natural hepatotoxic blooms samples (microcystins) and cultured neurotoxic saxitoxins producer samples analyzed in this study give us strong indications of that toxin s influence on the zooplanktonic community structure in tropical aquatic environments. Eleven cyanobacteria strains were isolated, representing 6 species: Anabaenopsis sp., Cylindrospermopsis raciborskii, Chroococcus sp., Microcystis panniformis, Geitlerinema unigranulatum e Planktothrix agardhii. None presented toxicity in Swiss mice. The strains were catalogued and deposited in the Laboratório de Ecologia e Toxicologia de Organismos Aquáticos (LETMA), in UFRN, and will be utilized in ecotoxicológical and ecophysiological studies, aiming to clarify the causes and control of cyanobacterial blooms in aquatic environments in RN. This state s reservoirs must receive broader attention from the authorities, considering the constant blooms occurring in waters used for human consumption
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Rutilus frisii Kutum is one of the most precious fish in the Caspian Sea. Investigation of the various aspects of its biocharactristics. Including its parasite fauna and ecological aspects are of prime importance. In this study the farmed kutum fry were on the focus of investigation in various seasons of the year and prior to their being released in the sea. This included also the study on the kutum spawners caught both from liver and the sea. The results were that 17 external and internal parasite species were distinct within different organs which were further identified down to genus and species. The single celled parasites identified included Ichthyophthirius multifilils, Chilodonella hexastica, Chilodonella pisicola, Trichodina sp Along with the monogene parasites that included Paradiplozoon chazaricum, D. rarissimus, D. turaliensis, D. nybelini, Dactylogyrus frisii. Meanwhile Diplostomum spathaceum constituted the single eyed parasites and the intestinal termatode were Aspidogaster limacoides, Asymphyoldora kubanicum as well as Bothriocephalus gowkongeniss as the sestads. The nematodes defrentiated were Raphidascaris acus, Dioctophyma renale, and Eustrongylides excisus followed by Lernaea cyprinacea as a crustacean. In this study, infestations by single celled parasites, crustaceans and sestod were found to be present only among the farmed kutum fry which varied in terms of percentage and intensity of infection as well as the parasite species and season of the year. The highest percentage of infection among kutum fry and spawners in both fresh water and in the sea during all seasons belonged to monogene parasites (33%). This was up to 100% among spawners. Infection caused by nematodes was exclusively detected among riverine spawners (7.5-5%) and the infection by Asymphyoldora kubanicum and Aspidogaster limacoides among Spawners caught at Sea and rivers varied within different seasons of the year. The infestation of Metacercer diplostomum spathaceum among kutum fry was 12% which compared to spawners was in slightly higher level. The study could identify Dioctophyma renale for the first time in the country and Eustrongylidis excisu was also detected among Rutilus frisii kutum.
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Fish species and subspecies occurring in fresh water in the North of Vietnam are systematically described. Their geographical distribution is given.
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Grain finishing of cattle has become increasingly common in Australia over the past 30 years. However, interest in the associated environmental impacts and resource use is increasing and requires detailed analysis. In this study we conducted a life cycle assessment (LCA) to investigate impacts of the grain-finishing stage for cattle in seven feedlots in eastern Australia, with a particular focus on the feedlot stage, including the impacts from producing the ration, feedlot operations, transport, and livestock emissions while cattle are in the feedlot (gate-to-gate). The functional unit was 1 kg of liveweight gain (LWG) for the feedlot stage and results are included for the full supply chain (cradle-to-gate), reported per kilogram of liveweight (LW) at the point of slaughter. Three classes of cattle produced for different markets were studied: short-fed domestic market (55–80 days on feed), mid-fed export (108–164 days on feed) and long-fed export (>300 days on feed). In the feedlot stage, mean fresh water consumption was found to vary from 171.9 to 672.6 L/kg LWG and mean stress-weighted water use ranged from 100.9 to 193.2 water stress index eq. L/kg LWG. Irrigation contributed 57–91% of total fresh water consumption with differences mainly related to the availability of irrigation water near the feedlot and the use of irrigated feed inputs in rations. Mean fossil energy demand ranged from 16.5 to 34.2 MJ lower heating values/kg LWG and arable land occupation from 18.7 to 40.5 m2/kg LWG in the feedlot stage. Mean greenhouse gas (GHG) emissions in the feedlot stage ranged from 4.6 to 9.5 kg CO2-e/kg LWG (excluding land use and direct land-use change emissions). Emissions were dominated by enteric methane and contributions from the production, transport and milling of feed inputs. Linear regression analysis showed that the feed conversion ratio was able to explain >86% of the variation in GHG intensity and energy demand. The feedlot stage contributed between 26% and 44% of total slaughter weight for the classes of cattle fed, whereas the contribution of this phase to resource use varied from 4% to 96% showing impacts from the finishing phase varied considerably, compared with the breeding and backgrounding. GHG emissions and total land occupation per kilogram of LWG during the grain finishing phase were lower than emissions from breeding and backgrounding, resulting in lower life-time emissions for grain-finished cattle compared with grass finishing.
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Food production account for significant share of global environmental impacts. Impacts are global warming, fresh water use, land use and some non-renewable substance consumption like phosphorous fertilizers. Because of non-sustainable food production, the world is heading to different crises. Both food- and freshwater crises and also land area and phosphorous fertilizer shortages are one of many challenges to overcome in near future. The major protein sources production amounts, their impacts on environment and uses are show in this thesis. In this thesis, a more sustainable than conventional way of biomass production for food use is introduced. These alternative production methods are photobioreactor process and syngas-based bioreactor process. The processes’ energy consumption and major inputs are viewed. Their environmental impacts are estimated. These estimations are the compared to conventional protein production’s impacts. The outcome of the research is that, the alternative methods can be more sustainable solutions for food production than conventional production. However, more research is needed to verify the exact impacts. Photobioreactor is more sustainable process than syngas-based bioreactor process, but it is more location depended and uses more land area than syngas-based process. In addition, the technology behind syngas-based application is still developing and it can be more efficient in the future.
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During the period from 2011 - 2015 with the aim of this study was to systematically review and in particular the revised classification of the Persian Gulf (and the Strait of Hormuz) and to obtain new information about the final confirmed list of fish species of Iranian waters of the Persian Gulf (and Hormuz Strait), samples of museums, surveys and sampling, and comparative study of all available sources and documentation was done. Classification systematic of sharks and batoids and bony fishes. Based on the results, the final list of approved fish of the Persian Gulf (including the Strait of Hormuz and Gulf of Oman border region) are 907 species in 157 families, of which 93 species of fish with 28 cartilaginous families (including 18 families with 60 species and 10 families with 34 species of shark and batoids); and 129 families with 814 species of bony fishes are. The presence of 11 new family with only one representative species in the area include Veliferidae, Zeidae, Sebastidae, Stomiidae, Dalatiidae, Zanclidae, Pempheridae, Lophiidae Kuhliidae, Etmoptridae and Chlorophthalmidae also recently introduced and approved. The two families based Creediidae Clinidae and their larvae samples for newly identified area. 62 families with mono-species and 25 families with more than 10 species are present including Gobiidae (53), Carangide (48), Labride (41), Blenniidae (34), Apogonidae (32) and Lutjanidae (31) of bony fishes, Carcharhinidae (26) of sharks and Dasyatidae (12) in terms of number of species of batoids most families to have their data partitioning. Also, 13 species as well as endemic species introduced the Persian Gulf and have been approved in terms of geographical expansion of the Persian Gulf are unique to the area.Two species of the family Poeciliidae and Cyprinodontidae have species of fresh water to the brackish coastal habitats have found a way;in addition to 11 types of families Carcharhinidae, Clupeidae, Chanidae, Gobidae, Mugilidae, Sparidae also as a species, with a focus on freshwater river basins in the south of the country have been found. In this study, it was found that out of 907 species have been reported from the study area, 294 species (32.4 %) to benthic habitats (Benthic habitats) and 613 species (67.6 %) in pelagic habitats (Pelagic habitats) belong. Coral reefs and rocky habitats in the range of benthic fish (129 species - 14.3 %) and reef associated fishes in the range of pelagic fishes (432 species – 47.8 %), the highest number and percentage of habitat diversity (Species habitats) have been allocated. As well as fish habitats with sea grass and algae beds in benthic habitat (17 species- 1.9 %) and pelagic - Oceanic (Open sea) in the whole pelagic fish (30 species – 3.3 %), the lowest number and percentage of habitat diversity into account. From the perspective of animal geography (Zoogeography) and habitat overlaps and similarities (Habitat overlapping) fish fauna of the Persian Gulf compared with other similar seas (tropical and subtropical, and warm temperate) in the Indian Ocean area - calm on the surface, based on the presence of certain species that the fish fauna of the Persian Gulf to the Red Sea and the Bay of Bengal (East Arabian Sea) compared to other regions in the Indian Ocean (Pacific) is closer (about 50%), and the Mediterranean (East area) and The Hawaiian Islands have the lowest overlap and similarity of habitat and species (about 10%).
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Salinity gradient power (SGP) is the energy that can be obtained from the mixing entropy of two solutions with a different salt concentration. River estuary, as a place for mixing salt water and fresh water, has a huge potential of this renewable energy. In this study, this potential in the estuaries of rivers leading to the Persian Gulf and the factors affecting it are analysis and assessment. Since most of the full water rivers are in the Asia, this continent with the potential power of 338GW is a second major source of energy from the salinity gradient power in the world (Wetsus institute, 2009). Persian Gulf, with the proper salinity gradient in its river estuaries, has Particular importance for extraction of this energy. Considering the total river flow into the Persian Gulf, which is approximately equal to 3486 m3/s, the amount of theoretical extractable power from salinity gradient in this region is 5.2GW. Iran, with its numerous rivers along the coast of the Persian Gulf, has a great share of this energy source. For example, with study calculations done on data from three hydrometery stations located on the Arvand River, Khorramshahr Station with releasing 1.91M/ energy which is obtained by combining 1.26m3 river water with 0.74 m3 sea water, is devoted to itself extracting the maximum amount of extractable energy. Considering the average of annual discharge of Arvand River in Khorramshahr hydrometery station, the amount of theoretical extractable power is 955 MW. Another part of parameters that are studied in this research, are the intrusion length of salt water and its flushing time in the estuary that have a significant influence on the salinity gradient power. According to the calculation done in conditions HWS and the average discharge of rivers, the maximum of salinity intrusion length in to the estuary of the river by 41km is related to Arvand River and the lowest with 8km is for Helle River. Also the highest rate of salt water flushing time in the estuary with 9.8 days is related to the Arvand River and the lowest with 3.3 days is for Helle River. Influence of these two parameters on reduces the amount of extractable energy from salinity gradient power as well as can be seen in the estuaries of the rivers studied. For example, at the estuary of the Arvand River in the interval 8.9 days, salinity gradient power decreases 9.2%. But another part of this research focuses on the design of a suitable system for extracting electrical energy from the salinity gradient. So far, five methods have been proposed to convert this energy to electricity that among them, reverse electro-dialysis (RED) method and pressure-retarded osmosis (PRO) method have special importance in practical terms. In theory both techniques generate the same amount of energy from given volumes of sea and river water with specified salinity; in practice the RED technique seems to be more attractive for power generation using sea water and river water. Because it is less necessity of salinity gradient to PRO method. In addition to this, in RED method, it does not need to use turbine to change energy and the electricity generation is started when two solutions are mixed. In this research, the power density and the efficiency of generated energy was assessment by designing a physical method. The physical designed model is an unicellular reverse electro-dialysis battery with nano heterogenic membrane has 20cmx20cm dimension, which produced power density 0.58 W/m2 by using river water (1 g NaCl/lit) and sea water (30 g NaCl/lit) in laboratorial condition. This value was obtained because of nano method used on the membrane of this system and suitable design of the cell which led to increase the yield of the system efficiency 11% more than non nano ones.
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Em peixes, o cobre (Cu) é absorvido a partir da água, via branquial, e pela ingestão de água e alimento, via gastrintestinal. Para evitar reações não específicas prejudiciais e suprir proteínas dependentes de Cu, existem transportadores específicos, como as proteínas de absorção de alta afinidade ao Cu (CTR1) e as Cu-ATPases (ATP7), que auxiliam na translocação intracelular do metal. No presente estudo, os genes CTR1 e ATP7B foram identificados em Poecilia vivipara e os seus transcritos foram quantificados por RT-qPCR nas brânquias, no fígado e no intestino de guarús expostos (96 h) ao Cu (0, 5, 9 e 20 µg/L) em água doce e salgada (salinidade 24). Foram identificadas novas sequências nucleotídicas dos genes CTR1 (1560 pb, completa) e ATP7B (617 pb, parcial), as quais tiveram altos valores de identidade com as descritas para Fundulus heteroclitus (CTR1=81%) e Sparus aurata (ATP7B=81%). A análise por RT-qPCR indicou níveis de transcrição para CTR1 e ATP7B em todos os tecidos analisados. Em guarús na água doce, a maior expressão da CTR1 e da ATP7B se deu no fígado. Em guarús na água salgada, a maior expressão da CTR1 ocorreu no intestino, enquanto a da ATP7B se deu no fígado e intestino. Na água doce, a exposição ao Cu aumentou o conteúdo branquial e hepático de Cu, diminuiu os transcritos de CTR1 e ATP7B nas brânquias e aumentou os transcritos destes genes no fígado, sem alterar o conteúdo corporal de Cu. Na água salgada, a exposição ao Cu aumentou o conteúdo de Cu e diminuiu o transcrito de ATP7B no intestino, sem alterar o conteúdo corporal de Cu nos P. vivipara. Estes resultados indicam que a homeostasia do Cu em P. vivipara envolve a redução da expressão do CTR1 e ATP7B nas brânquias (água doce) e intestino (água salgada) para limitar a absorção do Cu e o aumento da expressão destes genes no fígado (água doce) para facilitar o armazenamento e desintoxicação do Cu.
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The purpose of this dissertation is to evaluate the potential downstream influence of the Indian Ocean (IO) on El Niño/Southern Oscillation (ENSO) forecasts through the oceanic pathway of the Indonesian Throughflow (ITF), atmospheric teleconnections between the IO and Pacific, and assimilation of IO observations. Also the impact of sea surface salinity (SSS) in the Indo-Pacific region is assessed to try to address known problems with operational coupled model precipitation forecasts. The ITF normally drains warm fresh water from the Pacific reducing the mixed layer depths (MLD). A shallower MLD amplifies large-scale oceanic Kelvin/Rossby waves thus giving ~10% larger response and more realistic ENSO sea surface temperature (SST) variability compared to observed when the ITF is open. In order to isolate the impact of the IO sector atmospheric teleconnections to ENSO, experiments are contrasted that selectively couple/decouple the interannual forcing in the IO. The interannual variability of IO SST forcing is responsible for 3 month lagged widespread downwelling in the Pacific, assisted by off-equatorial curl, leading to warmer NINO3 SST anomaly and improved ENSO validation (significant from 3-9 months). Isolating the impact of observations in the IO sector using regional assimilation identifies large-scale warming in the IO that acts to intensify the easterlies of the Walker circulation and increases pervasive upwelling across the Pacific, cooling the eastern Pacific, and improving ENSO validation (r ~ 0.05, RMS~0.08C). Lastly, the positive impact of more accurate fresh water forcing is demonstrated to address inadequate precipitation forecasts in operational coupled models. Aquarius SSS assimilation improves the mixed layer density and enhances mixing, setting off upwelling that eventually cools the eastern Pacific after 6 months, counteracting the pervasive warming of most coupled models and significantly improving ENSO validation from 5-11 months. In summary, the ITF oceanic pathway, the atmospheric teleconnection, the impact of observations in the IO, and improved Indo-Pacific SSS are all responsible for ENSO forecast improvements, and so each aspect of this study contributes to a better overall understanding of ENSO. Therefore, the upstream influence of the IO should be thought of as integral to the functioning of ENSO phenomenon.
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This work had as objective tests therapeutic treatments seeking the monogenea eradication in fingerlings Florida Pompano (Trachinotus carolinus) servants in cage net in the area of Ubatuba, State of São Paulo. The fingerlings presented an accentuated weigh loss and strong discoloration and through observation of scraped of gills under light microscope were identified a high amount of monogenea. Three treatments were tested in form of baths: T1 (fresh water for 5 minutes); T2 (formalin: 1: 1.000 for 20 minutes) and T3: (formalin: 1:4.000 for 30 minutes). The treatments were appraised through scraped of gills, mounted among you laminate and laminulas and observed to the light microscope. It was observed that in the tested conditions all of the treatments were efficient in the elimination of the monogenea without presenting lethality to the fish. The treatment is recommended T I (take a bath in fresh water for 5 minutes) for the facility in the application and for the absence of use of chemical products.
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The incidence of toxic cyanobacterial blooms is one of the important consequences of eutrophication in aquatic ecosystems. It is a very common phenomenon in reservoirs and shrimp ponds in the State of Rio Grande do Norte (RN), Brazil. Cyanobacterias produce toxins which can affect aquatic organisms and men trough the food chain. Aiming to contribute to the studies of cyanobacterias in RN, we propose: a) to evaluate the toxicity of isolated cyanobacterias in important fresh-water environments; and b) to verify the effects of both natural and cultured blooms occurred in reservoirs for human supply and in the cladoceran Ceriodaphnia silvestrii. This study was carried out using samples of natural blooms occurred between March and October of 2004 in Gargalheiras Dam (08º L e 39º W), in July of 2004 in Armando Ribeiro Gonçalves Dam (06o S e 37o W) and in commercial shrimp ponds (Litopenaeus vannamei) located in fresh-water environments. The samples were collected with plankton net (20µm.) for identification, isolation and obtaining of phytoplanktonic biomass for liophilization and later toxicity bioassays. The toxicity of cultured samples and natural blooms was investigated through bioassays in Swiss mice. Quantification of cyanobacteria in samples was conducted following the Ütermol method, with 300mL samples fixed with lugol. The toxicity test with Ceriodaphnia silvestrii followed ABNT, 2001 recommendations, and were accomplished with natural hepatotoxic bloom s samples and cultured samples of both non-toxic and neurotoxic C. raciborskii. In this test, five newborns, aged between 6 and 24 hours, were exposed to different concentrations (0 a 800 mg.L-1) of crude cyanobacterial extracts during 24 and 48 hours. Three replicates were used per treatment. The pH, temperature and dissolved oxygen at the beginning and after 24 and 48hours from the test were measured. We estimated the CL50 through the Trimmed Spearman-Karber method. The blooms were constituted by Microcystis panniformis, M. aeruginosa, Anabaena circinalis, Cylindrospermopsis raciborskii and Planktothrix agardhii, producers of mycrocistin-LR confirmed with HPLC analysis. Samples of hepatotoxic blooms registered toxinogenic potential for C. silvestrii, with CL50-24h value of 47.48 mg.L-1 and CL5048h of 38.15 mg.L-1 for GARG samples in march/2005; CL50-24h of 113,13 mg.L-1 and CL5048h of 88,24 mg.L-1 for ARG July/2004; CL50-24h of 300.39 mg.L-1 and CL50-48h of 149.89 mg.L-1 for GARG October/2005. For cultured samples, values of CL50-24h and CL50-48h for C. raciborskii toxic strains were 228.05 and 120.28 mg.L-1, respectively. There was no mortality of C. silvestrii during the tests with non-toxic C. raciborskii strain. The toxicity test with C. silvestrii presented good sensitivity degree to cyanotoxins. The toxicity of natural hepatotoxic blooms samples (microcystins) and cultured neurotoxic saxitoxins producer samples analyzed in this study give us strong indications of that toxin s influence on the zooplanktonic community structure in tropical aquatic environments. Eleven cyanobacteria strains were isolated, representing 6 species: Anabaenopsis sp., Cylindrospermopsis raciborskii, Chroococcus sp., Microcystis panniformis, Geitlerinema unigranulatum e Planktothrix agardhii. None presented toxicity in Swiss mice. The strains were catalogued and deposited in the Laboratório de Ecologia e Toxicologia de Organismos Aquáticos (LETMA), in UFRN, and will be utilized in ecotoxicológical and ecophysiological studies, aiming to clarify the causes and control of cyanobacterial blooms in aquatic environments in RN. This state s reservoirs must receive broader attention from the authorities, considering the constant blooms occurring in waters used for human consumption
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I utilized state the art remote sensing and GIS (Geographical Information System) techniques to study large scale biological, physical and ecological processes of coastal, nearshore, and offshore waters of Lake Michigan and Lake Superior. These processes ranged from chlorophyll a and primary production time series analysies in Lake Michigan to coastal stamp sand threats on Buffalo Reef in Lake Superior. I used SeaWiFS (Sea-viewing Wide Field-of-view Sensor) satellite imagery to trace various biological, chemical and optical water properties of Lake Michigan during the past decade and to investigate the collapse of early spring primary production. Using spatial analysis techniques, I was able to connect these changes to some important biological processes of the lake (quagga mussels filtration). In a separate study on Lake Superior, using LiDAR (Light Detection and Ranging) and aerial photos, we examined natural coastal erosion in Grand Traverse Bay, Michigan, and discussed a variety of geological features that influence general sediment accumulation patterns and interactions with migrating tailings from legacy mining. These sediments are moving southwesterly towards Buffalo Reef, creating a threat to the lake trout and lake whitefish breeding ground.