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Sample records for chaetoceros calcitrans paulsen

  1. Efficient solvent extraction of antioxidant-rich extract from a tropical diatom,Chaetoceros calcitrans (Paulsen) Takano 1968

    Institute of Scientific and Technical Information of China (English)

    Su Chern Foo; Fatimah Md Yusoff; Maznah Ismail; Mahiran Basri; Nicholas Mun Hoe Khong; Kim Wei Chan; Sook Kun Yau

    2015-01-01

    Objective:To compare thein vitro antioxidant capacity of a diatom,Chaetoceros calcitrans (C. calcitrans) extracted using six types of solvents. Methods:Each extract was evaluated in terms of extraction yield, total carotenoid, fucoxanthin content, total phenolic and antioxidant capacities (DPPH• andABTS•+ scavenging activity and iron chelating activity). Results: The methanol extract exhibited the highest yield [(22.71 ± 0.96) g/100 g dry weight (DW)], total carotenoid [(4.46 ± 0.36) mg/g DW], total phenolic [(2.49 ± 0.08) mg gallic acid equivalents/g DW] and second highest fucoxanthin content [(2.08 ± 0.03) mg fucoxanthin/g DW] as compared to other solvent extracts. Methanolic extract also exhibited significantly higher (P Conclusions: Methanol was the recommended solvent for the production of antioxidant rich extract fromC. calcitrans. Both carotenoids and phenolic acids were found to be positively correlated to the antioxidant capacities ofC. calcitrans. Lead bioactives confirmed by subsequent high performance liquid chromatography studies were fucoxanthin, gallic acid and protocatechuic acid.

  2. Efficient solvent extraction of antioxidant-rich extract from a tropical diatom,Chaetoceros calcitrans (Paulsen) Takano 1968简

    Institute of Scientific and Technical Information of China (English)

    Su; Chern; Foo; Fatimah; Md.Yusoff; Maznah; Ismail; Mahiran; Basri; Nicholas; Mun; Hoe; Khong; Kim; Wei; Chan; Sook; Kun; Yau

    2015-01-01

    Objective: To compare the in vitro antioxidant capacity of a diatom, Chaetoceros calcitrans(C. calcitrans) extracted using six types of solvents.Methods: Each extract was evaluated in terms of extraction yield, total carotenoid,fucoxanthin content, total phenolic and antioxidant capacities(DPPH and ABTS +scavenging activity and iron chelating activity).Results: The methanol extract exhibited the highest yield [(22.71 ± 0.96) g/100 g dry weight(DW)], total carotenoid [(4.46 ± 0.36) mg/g DW], total phenolic [(2.49 ± 0.08) mg gallic acid equivalents/g DW] and second highest fucoxanthin content [(2.08 ± 0.03) mg fucoxanthin/g DW] as compared to other solvent extracts. Methanolic extract also exhibited significantly higher(P < 0.05) scavenging(DPPH, ABTS +) and iron chelating activities.Conclusions: Methanol was the recommended solvent for the production of antioxidant rich extract from C. calcitrans. Both carotenoids and phenolic acids were found to be positively correlated to the antioxidant capacities of C. calcitrans. Lead bioactives confirmed by subsequent high performance liquid chromatography studies were fucoxanthin, gallic acid and protocatechuic acid.

  3. PENGARUH PEMBERIAN FeCl3 TERHADAP PERTUMBUHAN Chaetoceros calcitrans

    Directory of Open Access Journals (Sweden)

    Cahya Laila Oktaviana Putri

    2009-04-01

    Full Text Available Besi termasuk unsur yang esensial bagi makhluk hidup. Pada tumbuhan termasuk algae, besi berperan sebagai penyusun sitokrom dan klorofil. Selain itu, besi juga berperan dalam sistem enzim dan transfer elektron pada proses fotosintesis. Namun, belum diketahui konsentrasi yang tepat untuk pengunaannya oleh algae sehingga diperlukan penelitian yang dapat mengetahui konsentrasi pemakaian FeCl3 untuk perkembangan algae terutama untuk C. calcitrans. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh pemberian FeCl3 terhadap kepadatan C. calcitran sehingga dapat mengetahui konsentrasi FeCl3 yang paling baik terhadap kepadatan C. calcitran. Serta untuk Mengetahui kepadatan C. calcitran berdasarkan hari. Penelitian ini diawali dengan menyetock C. calcitran hingga kepadatan 400 ribu sel/ml kemudian dilanjutkan dengan mengkultur C. calcitran pada toples yang telah dibuat sama parameternya kecuali pemberian FeCl3 sesuai dengan perlakuan. Untuk menganalisa pengaruh pemberian FeCl3 pada konsentrasi yang bebeda terhadap kepadatan C. calcitrans digunakan analisa sidik ragam (ANOVA dua langkah dengan bantuan software SPSS 12 dan dilakukan uji lanjut Tukey (Multiple Comparisons untuk melihat perlakuan yang berbeda dengan membandingkan berbagai hasil perlakuan. Pada konsentrasi FeCl3 0 mg/l berbeda nyata (P<0,05 sedangkan konsentrai FeCl3 0,02 mg/l, 0,2  mg/l, 2 mg/l berbeda signifikan terhadap kepadatan C. calcitrans sehingga hanya konsentrasi FeCl3 0 mg/l yang mempengaruhi kepadatan C. calcitrans. Ini disebabkan karena pemberian konsentrasi terlalu sedikit dan selisih konsentrasi yang kecil sehingga tidak mempengaruhi kepadatan C. calcitrans. Sedangkan untuk hari  diperoleh hari ke-1 dan ke-7 merupakan hari yang signifikan terhadap kepadatan C. calcitrans.  Kata Kunci : Chaetoceros calcitrans, FeCl3 dan kepadatan

  4. Proximate composition analysis posterior to the cryopreservation of Chaetoceros calcitrans

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    Joan Salas-Leiva

    2015-12-01

    Full Text Available Objective. The effect of cryopreservation on the proximate composition of microalgae Chaetoceros calcitrans was evaluated. Materials and methods. C. calcitrans was cultured and cryopreserved using 5% (v/v dimethylsulfoxide as cryoprotectant. The freezing was controlled at a rate of 3°C/min, up to -60°C and then the microalgae were immersed in liquid nitrogen (-196°C. After storage in liquid nitrogen, microalgae were rapidly thawed out and subcultured. The percentage of proteins, lipids and carbohydrates was analyzed using absorption spectrophotometry and the organic matter was studied by gravimetric analysis. Results. There was no significant variation between the proximate composition of C. calcitrans cryopreserved and the controls (p>0.05. Conclusion. Our results show that, despite low cell recovery after the preservation of this organism at low temperatures, there is no apparent loss of nutritional characteristics caused by the storing process at low temperatures.

  5. A comparative study on growth performance and biochemical composition of mixed culture of Isochrysis galbana and Chaetoceros calcitrans with monocultures

    Digital Repository Service at National Institute of Oceanography (India)

    Phatarpekar, P.V.; Sreepada, R.A.; Pednekar, C.; Achuthankutty, C.T.

    The growth performance, biochemical composition and nutritive value of the mixed culture of Isochrysis galbana and Chaetoceros calcitrans, grown in batch cultures under laboratory conditions was compared with those in monoculture conditions...

  6. Phytoremediation of Cd2+ by Marine Phytoplanktons, Tetracelmis chuii and Chaetoceros calcitrans

    OpenAIRE

    Sjahrul, M

    2012-01-01

    The use of marine phytoplankton, Tetracelmis chuii and Chaetoceros calcitrans as phytoremediator has already been reported. However their use as phytoremediator on the cadmium polluted marine has not yet well understood. Therefore, this study was conducted to evaluate the influence of the Cd2+ concentration, interacting time, and medium pH on accumulation of Cd2+ in the phytoplankton. Methods of analysis and data collection were carried out on 1) the growth rate, the number of phy...

  7. Production of Biodiesel from Lipid of Phytoplankton Chaetoceros calcitrans through Ultrasonic Method

    OpenAIRE

    Raymond Kwangdinata; Indah Raya; Muhammad Zakir

    2014-01-01

    A research on production of biodiesel from lipid of phytoplankton Chaetoceros calcitrans through ultrasonic method has been done. In this research, we carried out a series of phytoplankton cultures to determine the optimum time of growth and biodiesel synthesis process from phytoplankton lipids. Process of biodiesel synthesis consists of two steps, that is, isolation of phytoplankton lipids and biodiesel synthesis from those lipids. Oil isolation process was carried out by ultrasonic extracti...

  8. Nutritional Content of Artemia sp. Fed with Chaetoceros calcitrans and Skeletonema costatum

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    VIVI ENDAR HERAWATI

    2014-12-01

    Full Text Available Artemia sp. is a natural food with high protein content, especially amino acid. Nowadays, Indonesia still relies on import for its supply. Hence, the utilization of local Artemia sp. as an alternative to the imported product is recommended as it contains more protein and less expensive. The advantages of local Artemia sp. is its better crystal quality as it is still fresh. It also provides better income for salt farmers because waste water from salt farm can be used to culture Artemia sp.. This research is aimed at determining the quality of locally-produced Artemia sp., by evaluation of its essential amino acid and fatty acid profiles after treatments. Our results indicated that Artemia sp. cysts with good quality were produced after 8 hours and Artemia sp. reaches a hatching rate of 1,320,000 cysts (95% after 27 hours. We also found an indication that the best feed concentration was a mix of 60% Chaetoceros calcitrans with 40% Skeletonema costatum. Fatty acid profile analyses showed that the highest SAFA (12.86% and PUFA (29.91% were gained after feeding with Chaetoceros calcitrans, whereas the highest HUFA (4.93% was gained after feeding with Skeletonemacostatum. Essential amino acid profile analyses revealed the highest content of amino acid (18912.62 ppm was after feeding with a combination of Chaetoceros calcitrans and Skeletonema costatum. Finally, the proper water quality during research was at 25-30 oC of temperature, 30-31 ppt of salinity, pH 7.8-8.9, and DO was at 3.0-4.4 mg/L.

  9. Production of Biodiesel from Lipid of Phytoplankton Chaetoceros calcitrans through Ultrasonic Method

    Directory of Open Access Journals (Sweden)

    Raymond Kwangdinata

    2014-01-01

    Full Text Available A research on production of biodiesel from lipid of phytoplankton Chaetoceros calcitrans through ultrasonic method has been done. In this research, we carried out a series of phytoplankton cultures to determine the optimum time of growth and biodiesel synthesis process from phytoplankton lipids. Process of biodiesel synthesis consists of two steps, that is, isolation of phytoplankton lipids and biodiesel synthesis from those lipids. Oil isolation process was carried out by ultrasonic extraction method using ethanol 96%, while biodiesel synthesis was carried out by transesterification reaction using methanol and KOH catalyst under sonication. Weight of biodiesel yield per biomass Chaetoceros calcitrans is 35.35%. Characterization of biodiesel was well carried out in terms of physical properties which are density and viscosity and chemical properties which are FFA content, saponification value, and iodine value. These values meet the American Society for Testing and Materials (ASTM D6751 standard levels, except for the viscosity value which was 1.14 g·cm−3.

  10. Toxicity of mercury and copper to marine phytoplankton, Dunaliella salina, Tetraselmis sp. and Chaetoceros calcitrans

    Directory of Open Access Journals (Sweden)

    Chomrung, A.

    2005-07-01

    Full Text Available Static 96-hour phytoplankton growth tests were carried out to measure the toxicity of mercury (Hg and copper (Cu on growth (cell density and chlorophyll a content of three marine phytoplankton species: Dunaliella salina, Tetraselmis sp. and Chaetoceros calcitrans. The experiments were carried out at a temperature of 27±1ºC, using natural seawater (salinity 30 psu filtered with a 0.4 μ polycarbonate membrane, under continuous illumination of 3800±200 lux and they were repeated three times for each metal. Resultsshowed that C. calcitrans was the most sensitive species to Hg and Cu, followed by Tetraselmis sp. and D. salina, respectively. In addition, Hg was found to be more toxic to the three species than Cu. The mean IC50 values of Hg on growth of D. salina, Tetraselmis sp. and C. calcitrans were 0.277, 0.144 and 0.043 mg L-1, respectively, while those of Cu were 1.132, 0.270 and 0.090 mg L-1, respectively.

  11. Índice de desarrollo y supervivencia de larvas del camarón azul Litopenaeus stylirostris (Stimpson, 1871), alimentadas con diferentes concentraciones de Chaetoceros calcitrans (Paulsen)

    OpenAIRE

    Daniel E Godínez; Arnulfo H Díaz; María del C Gallo

    2005-01-01

    Se llevaron a cabo ensayos alimenticios con larvas del camarón azul (Litopenaeus stylirostris) utilizando cuatro diferentes concentraciones de la microalga Chaetoceroscalcitrans (30000, 60000, 90000 y 120000 cél/ml), con una concentración constante por tratamiento de 10000 cél/ml de Tetraselmis suecica y seis nauplios por ml de Artemia franciscana recién eclosionada. El período de prueba se inició a partir del sub estadio zoea 1 y concluyó hasta la aparición de misis 3. En cada ensayo fueron...

  12. The Paulsen Problem in Operator Theory

    OpenAIRE

    Casazza, Peter G.; Cahill, Jameson

    2011-01-01

    The Paulsen Problem in Hilbert space frame theory has proved to be one of the most intractable problems in the field. We will help explain why by showing that this problem is equivalent to a fundamental, deep problem in operator theory. Along the way we will give a new exact computation for chordal distances, we will give a generalization of these problems and we will spell out exactly the complementary versions of the problem.

  13. [A Stomoxys calcitrans outbreak on a dairy farm].

    Science.gov (United States)

    Betke, P; Schultka, H; Ribbeck, R

    1986-03-01

    In late summer and autumn of 1982 Stomoxys calcitrans disturbed cattle on a dairy farm and scourged the people working there. Both actively and passively Stomoxys calcitrans got into the cowsheds from its nearby breeding sites on open silos. The successful fly control combined sanitary measures with the application of pyrethrum insecticide aerosol. PMID:3717689

  14. Growth and proximate composition of the Chaetoceros calcitrans f. pumilus under different temperature, salinity and carbon dioxide levels

    Digital Repository Service at National Institute of Oceanography (India)

    Raghavan, G.; Haridevi, C.K.; Gopinathan, C.P.

    . Carbohydrates were increased while lipids and protein decreased at the highest salinity (35 + or - 0.9). These results should be taken into consideration when evaluating the dietary value of this micro alga for aquaculture....

  15. Effects of twelve pesticides on larvae of oysters (Crassostrea gigas) and on two species of unicellular marine algae (Isochrysis galbana and Chaetoceros calcitrans)

    OpenAIRE

    His, Edouard; Seaman, Matthias

    1993-01-01

    The effects of seven herbicides, four insecticides and one molluscicide were tested at concentrations of up to 10 mg/l on larvae of oysters, Crassostrea gigas (9 days exposure), and on laboratory cultures of the algae Isochrysis galbana and Chaeloceros calcilrans (21 days exposure). Ali of the pesticides tested had significant toxic effects on at least one of the test organisms. The strongest effects were those of lindane and isoproturon on survival and growth of C.gigas larvae, and of iso...

  16. Populational dynamics of Stomoxys calcitrans (Linneaus) (Diptera: Muscidae) in three biocenosis, Minas Gerais, Brazil.

    Science.gov (United States)

    Rodríguez-Batista, Z; Leite, R C; Oliveira, P R; Lopes, C M L; Borges, L M F

    2005-06-30

    Populational flux of the adult phase of Stomoxys calcitrans was observed in the municipal district of Pedro Leopoldo, Minas Gerais, Brazil. Three biocenoses were selected for the study: stable agrobiocenosis, pastural agrobiocenosis and eubiocenosis. The occurrence and the populational flux of the insects, using the Magoon trap for their capture, were established. For each trap located in different biocenoses, a crossbred calf (Bos taurusxBos indicus) approximately 6-month-old was used as "live bait," exposed weekly for 48h in the traps. Of the three agrobiocenoses studied, the stable agrobiocenosis contributed the greatest number of specimens of. S. calcitrans captured, corresponding to 96.9% of the total flies of this species collected. S. calcitrans shows seasonal behavior for approximately 6 months (spring and summer being the rainiest months of the year). The population peaked during the months of November and December. During the months of July and August, there was no capture of flies. PMID:15908125

  17. Stable Fly, Stomoxys calcitrans (L.), Dispersal and Governing Factors.

    Science.gov (United States)

    Showler, Allan T; Osbrink, Weste L A

    2015-01-01

    Although the movement of stable fly, Stomoxys calcitrans (L.), has been studied, its extent and significance has been uncertain. On a local scale (farm locations where herbivorous livestock regularly congregate. Small numbers emigrate from livestock congregation sites in search of other hosts and oviposition substrate, mostly within distance dispersal (>13 km) is mainly wind-driven by weather fronts that carry stable flies from inland farm areas for up to 225 km to beaches of northwestern Florida and Lake Superior. Stable flies can reproduce for a short time each year in washed-up sea grass, but the beaches are not conducive to establishment. Such movement is passive and does not appear to be advantageous to stable fly's survival. On a regional scale, stable flies exhibit little genetic differentiation, and on the global scale, while there might be more than one "lineage", the species is nevertheless considered to be panmictic. Population expansion across much of the globe likely occurred from the late Pleistocene to the early Holocene in association with the spread of domesticated nomad livestock and particularly with more sedentary, penned livestock. PMID:26816486

  18. The stable fly (Stomoxys calcitrans) (Diptera: Muscidae) recorded from the Faroes

    DEFF Research Database (Denmark)

    Nielsen, Søren Achim; Bloch, Dorete

    can reproduce all the year in the byres. Both sexes are blood feeding and attack vertebrates with preference for cattle and other ungulates. By high fly population the biting activity can result in reduction of milk and bodyweight in the livestock. S. calcitrans was probably introduced into the Faroes...

  19. Geographic distribution of stomoxyine flies (Diptera: Muscidae) and diurnal activity of Stomoxys calcitrans in Thailand.

    Science.gov (United States)

    Muenworn, Vithee; Duvallet, Gerard; Thainchum, Krajana; Tuntakom, Siripun; Tanasilchayakul, Somchai; Prabaripai, Atchariya; Akratanakul, Pongthep; Sukonthabhirom, Suprada; Chareonviriyaphap, Theeraphap

    2010-09-01

    Stomoxyine flies (Stomoxys spp.) were collected in 10 localities of Thailand using the Vavoua traps. These localities represented four major ecological settings, as follows: small local dairy farms, large industrial dairy farms, a national park, and one elephant conservation area. Three species of stable flies were identified in the following proportions: Stomoxys calcitrans (91.5%), Stomoxys indicus (7.9%), and Stomoxys sitiens (0.6%). The number of flies collected differed significantly among collection sites (chi2 = 360.15, df=3, P flies was captured in dairy farms. Seasonal and daily activity of S. calcitrans was observed during a 1-yr period at two selected locations (Dairy Farming Promotion Organization of Thailand and Khao Kheow Open Zoo). S. calcitrans was more abundant during the rainy season (March-September), but was not associated with the total rainfall (r2 = 0.0002, P > 0.05). Peak of daily flight activity of males S. calcitrans was at 1000 and 1600 h, whereas females showed an increase of activity all along the day until 1600 h. A better understanding of stomoxyine fly behavior related to patterns of daily activity will facilitate and improve the efficiency of fly control measures in private and government sectors. PMID:20939373

  20. Effects of Reserpine on Reproduction and Serotonin Immunoreactivity in the Stable Fly Stomoxys Calcitrans (L.)

    Science.gov (United States)

    Biogenic amines are known to play critical roles in key insect behaviors such as feeding and reproduction. This study documents the effects of reserpine on mating and egg-laying behaviors of the stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), which is one of the most economically significa...

  1. Efficacy of knightstick traps and sticky wraps for attraction and capture of stable flies (Stomoxys calcitrans)

    Science.gov (United States)

    The stable fly, Stomoxys calcitrans, is known as a noxious pest of livestock, particularly cattle, in many countries of the world. However, this blood-feeding fly can also pestiferous around pets and companion animals maintained outdoors. Two groups of animals, dogs and horses, are major hosts for s...

  2. Sugarcane stems as larval habitat for the stable fly (Stomoxys calcitrans in sugarcane plantations

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    Paulo H.D. Cançado

    2013-06-01

    Full Text Available Outbreaks of stable fly, Stomoxys calcitrans, cause losses for livestock producers located near sugarcane mills in Brazil, especially in southern Mato Grosso do Sul. The sugarcane mills are often pointed by local farmers as the primary source of these outbreaks; some mills also joined the farmers in combating the flies. Brazilian beef cattle production has great economic importance in similar level to bio-fuel production as ethanol. In this context, the wide-ranging knowledge on the biology and ecology of the stable fly, including larval habitats and their reproduction sites is extremely important for further development of control programs. This paper aims to report the occurrence and development of S. calcitrans larvae inside sugarcane stems in three municipalities of Mato Grosso do Sul. The sugarcane stems give protection against bad weather conditions and insecticide application. In this way, for sustainable sugarcane growth specific research concerning this situation should be conducted.

  3. Surtos por Stomoxys calcitrans em gado de corte no Mato Grosso do Sul

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    Antonio Thadeu M Barros

    2010-11-01

    Full Text Available A expansão da indústria sucroalcooleira tem levado à instalação de usinas de álcool em áreas tradicionalmente ocupadas pela pecuária de corte na região Centro-Oeste do País. Surtos pela mosca-dos-estábulos (Stomoxys calcitrans em bovinos Nelore têm sido relatados nos últimos dois anos em Mato Grosso do Sul, associados a estas usinas. Visitas em propriedades pecuárias e usinas foram realizadas em meados de novembro 2009, ao final de surtos por S. calcitrans ocorridos nos municípios de Angélica e Ponta Porã, MS. Entrevistas, observações e coletas de imaturos de dípteros foram realizadas nos locais e o material entomológico coletado foi levado ao laboratório para posterior emergência. Elevadas infestações pela mosca-dos-estábulos e comportamento de agrupamento dos bovinos foram observados. Sítios de reprodução foram encontrados nos locais e a emergência de S. calcitrans foi constatada nas amostras coletadas tanto nas fazendas como nas usinas. O conjunto de informações, observações in loco e resultados das amostragens possibilitaram realizar uma abordagem epidemiológica preliminar sobre a dinâmica dos referidos surtos por S. calcitrans e discutir potenciais fatores de risco.

  4. Sugarcane stems as larval habitat for the stable fly (Stomoxys calcitrans) in sugarcane plantations

    OpenAIRE

    Paulo H.D. Cançado; Taciany Ferreira; Eliane M. Piranda; Cleber O. Soares

    2013-01-01

    Outbreaks of stable fly, Stomoxys calcitrans, cause losses for livestock producers located near sugarcane mills in Brazil, especially in southern Mato Grosso do Sul. The sugarcane mills are often pointed by local farmers as the primary source of these outbreaks; some mills also joined the farmers in combating the flies. Brazilian beef cattle production has great economic importance in similar level to bio-fuel production as ethanol. In this context, the wide-ranging knowledge on the biology a...

  5. Stomoxys calcitrans as possible vector of Trypanosoma evansi among camels in an affected area of the Canary Islands, Spain

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    Noé Francisco Rodríguez

    2014-07-01

    Full Text Available Introduction Trypanosoma evansi was first identified in the Canary Islands in 1997, and is still present in a small area of the Archipelago. To date, the disease has exclusively affected camel herds, and has not been detected in any other animal hosts. However potential vectors of Trypanosoma evansi must be identified. Methods One Nzi trap was placed on a camel farm located in the infected area for a period of one year. Results Two thousand five hundred and five insects were trapped, of which Stomoxys calcitrans was the sole hematophagous vector captured. Conclusions Stomoxys calcitrans could be exclusively responsible for the transmission of Trypanosoma evansi among camels in the surveyed area, as other species do not seem to be infected by S. calcitrans in the presence of camels.

  6. Extensive Chaetoceros curvisetus bloom in relation to water quality in Port Blair Bay, Andaman Islands.

    Science.gov (United States)

    Begum, Mehmuna; Sahu, Biraja Kumar; Das, Apurba Kumar; Vinithkumar, Nambali Valsalan; Kirubagaran, Ramalingam

    2015-05-01

    Blooming of diatom species Chaetoceros curvisetus (Cleve, 1889) was observed in Junglighat Bay and Haddo Harbour of Port Blair Bay of Andaman and Nicobar Islands during June 2010. Physico-chemical parameters, nutrient concentrations and phytoplankton composition data collected from five stations during 2010 were classified as bloom area (BA) and non-bloom area (NBA) and compared. Elevated values of dissolved oxygen were recorded in the BA, and it significantly varied (p parametric multidimensional scaling (nMDS) ordinations; cluster analysis powered by SIMPROF test also grouped the stations as BA and NBA. PMID:25838063

  7. Desponte dos ramos da videira e seu efeito na qualidade dos frutos de 'Merlot' sobre os porta-enxertos 'Paulsen 1103' e 'Couderc 3309' Shoot topping on Merlot grapevines grafted on Paulsen 1103 and Couderc 3309 and its effects on the quality of grapes

    Directory of Open Access Journals (Sweden)

    Alberto Fontanella Brighenti

    2010-03-01

    Full Text Available A produção de uvas viníferas nas regiões de altitude do Estado de Santa Catarina é recente e existem poucos dados de pesquisa sobre o comportamento das diferentes cultivares neste local. Os objetivos do trabalho foram testar o efeito de diferentes níveis de desponte do dossel vegetativo e avaliar a influência de dois porta-enxertos nas características dos frutos produzidos. O experimento foi realizado em São Joaquim-SC (28º17'38" S e 49º55'54" W, a uma altitude média de 1.250 m, na Vinícola Villa Francioni, com a cultivar Merlot enxertada em 'Paulsen 1103' e 'Couderc 3309'. Os tratamentos consistiram no desponte em diferentes níveis, mantendo as áreas foliares de 4,5; 2,5; 2,0 e 1,5 m² kg-1 de uva em dois porta-enxertos. Foram avaliados número de bagas por cacho, diâmetro de bagas, pH, sólidos solúveis totais, antocianinas, índice de polifenóis totais, comprimento e peso de cacho. As plantas enxertadas em 'Paulsen 1103' apresentaram a máxima eficiência para o nível de desponte de 3,4 m² kg-1de uva, já as plantas enxertadas sobre 'Couderc 3309' apresentaram a máxima eficiência com a manutenção de uma área foliar de 3,0 m² kg-1 de uva. Os diferentes porta-enxertos não interferiram nos compostos fenólicos dos frutos. No ciclo de 2005/06, Couderc 3309 produziu frutos com maiores teores de sólidos solúveis totais e, no ciclo de 2006/07, produziu cachos mais pesados.The production of grapevines in regions of high altitude of Santa Catarina state is recent and there are few data on the behavior of different cultivars. The objective of this work was to verify the effect of different levels of shoot topping and evaluate the influence of two rootstocks on the characteristics of the fruit produced. The experiment was conducted in the city of São Joaquim, Santa Catarina state (28º17'38" S and 49º55'54" W, in an altitude of 1.250m, at Villa Francioni Vineyards, with Merlot grapevine grafted on Paulsen 1103 and Couderc

  8. Temperature-dependent functional response of Spalangia cameroni (Perkins) (Hymenoptera: Pteromalidae), a parasitoid of Stomoxys calcitrans (L.) (Diptera: Muscidae)

    DEFF Research Database (Denmark)

    Skovgård, Henrik; Nachman, Gösta

    2015-01-01

    The effects of host density, temperature, and burial depths on the functional response of the synovigenic parasitoid Spalangia cameroni (Perkins) attacking pupae of the stable fly Stomoxys calcitrans (L.) were examined. Five temperatures (15, 20, 25, 30, and 35 degrees C), six host densities (2, ...

  9. Use of secondary sewage water as a culture medium for Chaetoceros gracilis and Thalassiosira Sp (Chrysophyceae in laboratory conditions

    Directory of Open Access Journals (Sweden)

    Rauquírio André Albuquerque Marinho da Costa

    1999-01-01

    Full Text Available Experiments were carried out in order to test the efficiency of additions of secondary sewage as a culture medium for Chaetoceros gracilis and Thalassiosira sp (Chrysophyceae under laboratory conditions. These algae were cultivated in sea water with concentrations of 10%, 20%, 30% and 40% of wastewater. The results were compared with those obtained by the nutritive medium f2 of Guillard (1975. The best results in terms of cellular densities were observed at 40% additions. There were significant differences (significance levels of 5% between the nutritive medium f2 and the 40% additions for both the species. Maximum cellular densities observed for all additions tested were, 4,125.00 x 10³ cells/ml for Chaetoceros gracilis on the ninth day and 834.00 x 10³ cells/ml for Thalassiosira sp on the fifth day. Biomass was higher in the nutritive medium f2 than in the other treatments, reaching average values of 2,363μg/ml for Chaetoceros gracilis. At all experimental units, the best results were registered at 40% addition for Chaetoceros gracilis, where average values of 0.768μg/ml were observed on the fifth day, and at 30% additions for Thalassiosira sp where 0.883μg/ml were observed on the thirteenth day. It was concluded that secondary sewage could be used as a culture medium for the species tested here, after large scale tests.

  10. Effect of Low ph on Carbohydrate Production by a Marine Planktonic Diatom (Chaetoceros muelleri)

    International Nuclear Information System (INIS)

    Rising carbon dioxide (CO2) concentrations in the atmosphere due to human activity are causing the surface ocean to become more acidic. Diatoms play a pivotal role in biogeochemical cycling and ecosystem function in the ocean. ph affected the quantum efficiency of photosystem II and carbohydrate metabolism in a planktonic diatom (Chaetoceros muelleri), representative of a widely distributed genus. In batch cultures grown at low ph, the proportion of total carbohydrate stored within the cells decreased and more dissolved carbohydrates were exuded from the cells into the surrounding medium. Changes in productivity and the way in which diatoms allocate carbon into carbohydrates may affect ecosystem function and the efficiency of the biological carbon pump in a low ph ocean.

  11. Effect of Low pH on Carbohydrate Production by a Marine Planktonic Diatom (Chaetoceros muelleri

    Directory of Open Access Journals (Sweden)

    Daniel C. O. Thornton

    2009-01-01

    Full Text Available Rising carbon dioxide (CO2 concentrations in the atmosphere due to human activity are causing the surface ocean to become more acidic. Diatoms play a pivotal role in biogeochemical cycling and ecosystem function in the ocean. pH affected the quantum efficiency of photosystem II and carbohydrate metabolism in a planktonic diatom (Chaetoceros muelleri, representative of a widely distributed genus. In batch cultures grown at low pH, the proportion of total carbohydrate stored within the cells decreased and more dissolved carbohydrates were exuded from the cells into the surrounding medium. Changes in productivity and the way in which diatoms allocate carbon into carbohydrates may affect ecosystem function and the efficiency of the biological carbon pump in a low pH ocean.

  12. The study on the effect of NO on the growth of Chaetoceros curvisetus

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhengbin; WU Zhenzhen; LIU Chunying; XING Lei

    2006-01-01

    This article studied nitric oxide (NO) effect on the growth of Chaetoceros curvisetus in chemistry for the first time. Nitric oxide was added into the media with 4 different nutrient concentrations f/2, f/50, f/100, and f/200 when the alga was growing. The growth of C. curvisetus could be obviously promoted or inhibited during the cultivation process in NO enriched media of different concentrations.The growth curve in such media showed a sharp single peak that is the optimal NO concentration for the alga growth, which is consistent with the influence of NO on the growth of high plants. In addition, C.curvisetus can produce NO by itself during the growth. Therefore, using NO could effectively regulate the algae growth, which is important in real tide control and remediation.

  13. Global diversity of two widespread, colony-forming diatoms of the marine plankton, Chaetoceros socialis (syn. C. radians) and Chaetoceros gelidus sp. nov.

    Science.gov (United States)

    Chamnansinp, Atchaneey; Li, Yang; Lundholm, Nina; Moestrup, Øjvind

    2013-12-01

    Marine phytoplankton samples containing diatoms of the Chaetoceros socialis group were collected from Thailand, China, Denmark, and Greenland, and cells were isolated into culture for light and electron microscopy and DNA sequencing of D1-D3 of the LSU rDNA. Species of this lineage are characterized by three short and one long setae extending from each cell, the long setae from several cells joining into a common center to form large colonies, which are sometimes visible with the naked eye. Phylogenetic analyses including sequences from other parts of the world revealed segregation into three groups. Most sequences fell into two large clades, one comprising material from cold waters, whereas the other contained material from warmer waters. Strain CCMP 172 from the Strait of Georgia, Washington State, USA, formed a separate group. The warm-water species included Chinese and Thai material and therefore probably also material from the type locality of C. socialis, Hong Kong. It is characterized by all setae being covered by spines and the setae extending from the valve at some distance from the margin. In the resting spores, both valves are ornamented with spines. The cold-water material is characterized by three spiny and one mostly smooth long setae, and the setae extend from the valve near the margin. Both valves of the resting spore are smooth. This material is described as C. gelidus sp. nov. C. radians, described from the Baltic in 1894, is considered a synonym of C. socialis. CCMP172 is in many ways intermediate and probably constitutes a separate species. The published evidence on this globally distributed and sometimes bloom-forming group of species indicates higher species diversity than presently thought. PMID:27007633

  14. Nutrient compositions of cultured Skeletonema costatum, Chaetoceros curvisetus, and Thalassiosira nordenskiöldii

    Science.gov (United States)

    Pan, Shengjun; Shen, Zhiliang; Liu, Wenping; Han, Xiaotian; Miao, Hui; Ma, Haiqing

    2010-11-01

    We cultured different-sized fractions of dominant phytoplankton species, Skeletonema costatum, Chaetoceros curvisetus, and Thalassiosira nordenskiöldii, collected in different sea areas in various seasons, and measured and compared their C, N, P, Si contents. The N content of these species is similar, while the C, P, and Si contents of S. costatum from eutrophic Changjiang (Yangtze River) estuary are higher than those from Jiaozhou Bay (JZB), particularly the content of Si. The C, N, P, and Si contents of cultured phytoplankton in JZB increase with size fraction augmentation, and the percentages of C, N, and P follow the same trend, while the percentage of Si remain constant. Moreover, S. costatum from small-sized fraction assimilated Si more easily than C. curvisetus and T. nordenskiöldii, which is explained by the dominance of S. costatum under the conditions of low SiO3-Si concentration in JZB. The C, N, P, and Si contents of cultured S. costatum collected during summer and winter are higher, which is consistent with the phytoplankton blooming seasons in JZB. The SiO3-Si concentration of seawater during spring restrain the growth of phytoplankton, supported by the fact that the N, P, and Si contents and their ratios in cells of cultured S. costatum are low in spring season.

  15. Optimization of Alkaline Flocculation for Harvesting of Scenedesmus quadricauda #507 and Chaetoceros muelleri #862

    Directory of Open Access Journals (Sweden)

    Shuhao Huo

    2014-09-01

    Full Text Available A response surface methodology (RSM was used to evaluate the effects of pH and microalgal biomass concentration (BC on alkaline flocculating activity for harvesting one freshwater green algae Scenedesmus quadricauda #507 and one marine diatom Chaetoceros muelleri #862. The pH value and BC were in range of 9.0–12.0 and 0.20–2.30 g/L, respectively. Very high regression coefficient between the variables and the response indicates excellent evaluation of experimental data by second-order regressions. Optimum conditions for flocculating activity were estimated as follows: (i pH 11.6, BC 0.54 g/L for strain #507 and (ii pH 11.5, BC 0.42 g/L for strain #862. The maximum flocculating activity was around 94.7% and 100%, respectively. Furthermore, the addition of synthetic ocean water (SOW to the freshwater #507 culture can increase the flocculating activity from 82.13%–88.79% in low algae concentration (0.52 g/L and 82.92%–95.60% in high concentration (2.66 g/L.

  16. Produção de mudas de videira cv. Bordô/Paulsen 1103 pela enxertia de mesa com estratificação

    Directory of Open Access Journals (Sweden)

    Lari Maroli

    2014-09-01

    Full Text Available O emprego de práticas adequadas na implantação do vinhedo, principalmente o uso de mudas enxertadas com boa sanidade, é fator essencial para o sucesso da viticultura. O objetivo do trabalho foi testar temperatura de estratificação, uso do ácido indolbutírico (AIB, tipo e época de enxertia para produção de mudas da cultivar Bôrdo/Paulsen 1103 por enxertia de mesa com estratificação. No primeiro e no segundo experimentos, as estacas do porta-enxerto foram tratadas com AIB antes e após a estratificação, respectivamente. Ambos os experimentos foram conduzidos em blocos ao acaso, em esquema fatorial de 3 x 2 (temperaturas de estratificação: 19º; 24º e 29ºC x tipo enxertia: garfagem de topo e tipo Ômega, com quatro repetições, constituída por 10 unidades de observação cada. O terceiro experimento foi em blocos ao acaso, em esquema fatorial 4 x 2 (época de enxertia: maio, junho, julho e agosto x temperatura de estratificação: 19ºC e 24ºC, com quatro repetições de 20 unidades de observação cada. A técnica de enxertia empregada foi de garfagem de topo, com aplicação de AIB 2.000 mg L-1 após a saída da estratificação. Concluiu-se que a enxertia tipo garfagem de topo apresentou melhores resultados que o tipo Ômega. Recomenda-se a aplicação de AIB após estratificação. As temperaturas de 19ºC e 24ºC no período de estratificação favorecem a sobrevivência em relação a 29ºC. Com a realização da enxertia em meados de julho, e a utilização da temperatura de 19ºC na estratificação, pode-se obter elevada sobrevivência (86%, acompanhada de melhor desenvolvimento vegetativo e radicial.

  17. Mechanical transmission of Bacillus anthracis by stable flies (Stomoxys calcitrans) and mosquitoes (Aedes aegypti and Aedes taeniorhynchus).

    OpenAIRE

    Turell, M J; Knudson, G B

    1987-01-01

    We evaluated the potential of stable flies, Stomoxys calcitrans, and two species of mosquitoes, Aedes aegypti and Aedes taeniorhynchus, to transmit Bacillus anthracis Vollum 1B mechanically. After probing on Hartley guinea pigs with a bacteremia of ca. 10(8.6) CFU of B. anthracis per ml of blood, individual or pools of two to four stable flies or mosquitoes were allowed to continue feeding on either uninfected guinea pigs or A/J mice. All three insect species transmitted lethal anthrax infect...

  18. Analysis of expressed sequence tags from a significant livestock pest, the stable fly (Stomoxys calcitrans), identifies transcripts with a putative role in chemosensation and sex-determination

    Science.gov (United States)

    The stable fly, Stomoxys calcitrans, is one of the most significant pests of livestock in the United States. We are interested in the identification of targets for the development of novel control for this pest species, focusing on those molecules that play a role in successful feeding and reproduc...

  19. CHANGES IN CHLOROPHYLL A FLOURESCENCE AND PIGMENT RATIOS DURING DIFFERENT GROWTH PHASES OF A UNICELLULAR MARINE CHAETOCEROS (BACILLAROPHYCEAE) IN BATCH CULTURE

    Science.gov (United States)

    Interpretations of chlorophyll a fluorescence data are based largely on application with green algae and higher plants. This study evaluated the interpretation of fluorescence data for a unicellular marine diatom. Chaetoceros sp. was grown in 4-liter batch cultures on a 16:8, L:D...

  20. Repellency to Stomoxys calcitrans (Diptera: Muscidae) of plant essential oils alone or in combination with Calophyllum inophyllum nut oil.

    Science.gov (United States)

    Hieu, Tran Trung; Kim, Soon-Il; Lee, Sang-Guei; Ahn, Young-Joon

    2010-07-01

    The repellency to female Stomoxys calcitrans (L.) (Diptera: Muscidae) of 21 essential oils (EOs) alone or in combination with Calophyllum inophyllum L. (Clusiaceae) nut oil (tamanu oil) was examined using an exposed human hand bioassay. Results were compared with those of commonly used repellent N,N-diethyl-3-methylbenzamide (DEET). In tests with six human male volunteers at a dose of 0.5 mg/cm2, patchouli (protection time [PT], 3.67 h) was the most effective EO but less active than DEET (4.47 h), as judged by the PT to first bite. Very strong repellency also was produced by clove bud, lovage root, and clove leaf EOs (PT, 3.50-3.25 h), whereas strong repellency was obtained from thyme white EO (2.12 h). Thyme red, oregano, and geranium EOs exhibited moderate repellency (PT, 1.24-1.11 h). At 0.25 mg/cm2, protection time of clove bud, clove leaf, and lovage root EOs (PT, approximately equal to 1 h) was shorter than that of DEET (2.17 h). An increase in the protection time was produced by binary mixtures (PT, 2.68-2.04 h) of five EOs (clove bud, clove leaf, thyme white, patchouli, and savory) and tamanu oil (0.25:2.0 mg/cm2) compared with that of either the constituted essential oil or tamanu oil alone (PT, 0.56 h). The protection time of these binary mixtures was comparable with that of DEET. With the exception of savory EO, the other EOs, tamanu oil, and binary mixtures did not induce any adverse effects on the human volunteers at 0.5 mg/cm2. Thus, binary mixtures of essential oils and tamanu oil described merit further study as potential repellents for protection from humans and domestic animals from biting and nuisance caused by S. calcitrans. PMID:20695272

  1. Modulation of Medium-Chain Fatty Acid Synthesis in Synechococcus sp. PCC 7002 by Replacing FabH with a Chaetoceros Ketoacyl-ACP Synthase

    Science.gov (United States)

    Gu, Huiya; Jinkerson, Robert E.; Davies, Fiona K.; Sisson, Lyle A.; Schneider, Philip E.; Posewitz, Matthew C.

    2016-01-01

    The isolation or engineering of algal cells synthesizing high levels of medium-chain fatty acids (MCFAs) is attractive to mitigate the high clouding point of longer chain fatty acids in algal based biodiesel. To develop a more informed understanding of MCFA synthesis in photosynthetic microorganisms, we isolated several algae from Great Salt Lake and screened this collection for MCFA accumulation to identify strains naturally accumulating high levels of MCFA. A diatom, Chaetoceros sp. GSL56, accumulated particularly high levels of C14 (up to 40%), with the majority of C14 fatty acids allocated in triacylglycerols. Using whole cell transcriptome sequencing and de novo assembly, putative genes encoding fatty acid synthesis enzymes were identified. Enzymes from this Chaetoceros sp. were expressed in the cyanobacterium Synechococcus sp. PCC 7002 to validate gene function and to determine whether eukaryotic enzymes putatively lacking bacterial evolutionary control mechanisms could be used to improve MCFA production in this promising production strain. Replacement of the Synechococcus 7002 native FabH with a Chaetoceros ketoacyl-ACP synthase III increased MCFA synthesis up to fivefold. The level of increase is dependent on promoter strength and culturing conditions. PMID:27303412

  2. Induction of protease release of the resistant diatom Chaetoceros didymus in response to lytic enzymes from an algicidal bacterium.

    Science.gov (United States)

    Paul, Carsten; Pohnert, Georg

    2013-01-01

    Marine lytic bacteria can have a substantial effect on phytoplankton and are even capable to terminate blooms of microalgae. The bacterium Kordia algicida was reported to lyse cells of the diatom Skeletonema costatum and several other diatoms by a quorum sensing controlled excretion of proteases. However the diatom Chaetoceros didymus is fully resistant against the bacterial enzymes. We show that the growth curve of this diatom is essentially unaffected by addition of bacterial filtrates that are active against other diatoms. By monitoring proteases from the medium using zymography and fluorescence based activity assays we demonstrate that C. didymus responds to the presence of the lytic bacteria with the induced production of algal proteases. These proteases exhibit a substantially increased activity compared to the bacterial counterparts. The induction is also triggered by signals in the supernatant of a K. algicida culture. Size fractionation shows that only the >30 kD fraction of the bacterial exudates acts as an inducing cue. Implications for a potential induced defense of the diatom C. didymus are discussed. PMID:23469204

  3. Induction of protease release of the resistant diatom Chaetoceros didymus in response to lytic enzymes from an algicidal bacterium.

    Directory of Open Access Journals (Sweden)

    Carsten Paul

    Full Text Available Marine lytic bacteria can have a substantial effect on phytoplankton and are even capable to terminate blooms of microalgae. The bacterium Kordia algicida was reported to lyse cells of the diatom Skeletonema costatum and several other diatoms by a quorum sensing controlled excretion of proteases. However the diatom Chaetoceros didymus is fully resistant against the bacterial enzymes. We show that the growth curve of this diatom is essentially unaffected by addition of bacterial filtrates that are active against other diatoms. By monitoring proteases from the medium using zymography and fluorescence based activity assays we demonstrate that C. didymus responds to the presence of the lytic bacteria with the induced production of algal proteases. These proteases exhibit a substantially increased activity compared to the bacterial counterparts. The induction is also triggered by signals in the supernatant of a K. algicida culture. Size fractionation shows that only the >30 kD fraction of the bacterial exudates acts as an inducing cue. Implications for a potential induced defense of the diatom C. didymus are discussed.

  4. Determinação das exigências térmicas de Stomoxys calcitrans (L. (Diptera, Muscidae, em condições de laboratório Determination of thermal requirements of Stomoxys calcitrans (L. (Diptera, Muscidae, under laboratory conditions

    Directory of Open Access Journals (Sweden)

    M. Aguiar-Valgode

    1992-01-01

    Full Text Available The biology immature stage of Stomoxys calcitrans (L. was studied in the laboratory under four constant temperature. The study was carried out in biological incubators at 20, 25, 30 and 35-C; 65 ñ 10% relative humidity and 14 hours of photophase. The most favorable temperature for developing eggs, larval and pupal was 25-C, while 35-C proved to be harmful for a normal developing of S. calcitrans in larval stage. The incubation periods for egg were 69.90, 42.58, 26.10, 21.78 hours and 2.91, 1.77, 1.08, 0.90 days at 20, 25, 30, 35-C, respectively . The larval stage was 18.40, 11.63, 8.55 days and, the pupal stage, 8.60, 4.54, 3.60 days at 20, 25, 30-C, respectively. Threshold temperatures for males were a little higher than for females, however, this difference was lesser than 1-C. On the other hand, the quantity of energy (GD for developing females was a little higher than for males. No difference was observed between the two methods used for calculating the above mentioned biological parameters of S. calcitrans.

  5. Temperature benefits the photosynthetic performance of the diatoms Chaetoceros gracilis and Thalassiosira weissflogii when exposed to UVR.

    Science.gov (United States)

    Halac, S R; Villafañe, V E; Helbling, E W

    2010-12-01

    The aim of this study was to assess the combined effects of temperature and UVR on the photosynthesis performance of two diatoms -Chaetoceros gracilis and Thalassiosira weissflogii. In particular, we evaluated the role of UVR in inducing photoinhibition and the potential mitigation of this negative effect by an increase in temperature. Cultures were pre-acclimated at two temperatures - 18°C and 23°C - and exposed to different radiation treatments - UVR+PAR (280-700nm); UV-A+PAR (315-700nm) and PAR only (400-700nm) under two temperatures: 18°C (local surface summer water temperature) and 23°C (simulating a potential increase estimated by the year 2100). Exposure to natural solar radiation resulted in UVR-induced photoinhibition that was significantly higher in T. weissflogii than in C. gracilis. Both species benefited from the higher temperature (23°C) resulting in a lower photoinhibition as compared to samples exposed at 18°C. Inter-specific differences were determined in regard to the heat dissipation processes (NPQ) which were higher at high temperatures, and much more evident in C. gracilis than in T. weissflogii. The analyses of inhibition and recovery rates under different irradiances indicate that the balance between negative (inhibition) and positive (repair-dissipation) effects shifted towards a more positive balance with increasing temperature. Our results highlight for a beneficial effect of temperature on photosynthesis performance during exposure to UVR, although important inter-specific differences are found, probably due to differences in cell size as well as in their distribution within the oceanic realm (i.e., coastal versus oceanic species). PMID:20692849

  6. Toxicity of Zanthoxylum piperitum and Zanthoxylum armatum oil constituents and related compounds to Stomoxys calcitrans (Diptera: Muscidae).

    Science.gov (United States)

    Hieu, Tran Trung; Kim, Soon-Il; Ahn, Young-Joon

    2012-09-01

    Zanthoxylum plants (Rutaceae) have drawn attention because they contain insecticidal principles against insects. An assessment was made of the insecticidal and acetylcholinesterase (AChE) inhibitory activities of Zanthoxylum piperitum steam distillate and Zanthoxylum armatum seed oil, their 28 constituents, and eight structurally related compounds against female stable fly, Stomoxys calcitrans (L.). Results were compared with those of two organophosphorus insecticides chlorpyrifos and dichlorvos. Potent fumigant toxicity was observed with cuminaldehyde, thymol, (1S)-(-)-verbenone, (-)-myrtenal, carvacrol, (S)-(Z)-verbenol, Zanthoxylum piperitum steam distillate, cuminyl alcohol, Zanthoxylum armatum seed oil, piperitone, (-)-(Z)-myrtanol, and citronellal (LC50, 0.075-0.456 microg/cm3). However, they were five orders of magnitude less toxic than either chlorpyrifos or dichlorvos. An in vitro bioassay using female fly heads indicates that strong AChE inhibition was produced by citronellyl acetate, alpha-pinene, thymol, carvacrol, and alpha-terpineol (1.20-2.73 mM), but no direct correlation between fly toxicity and AChE inhibition by the test compounds was observed. Structure-activity relationships indicate that structural characteristics, such as carbon skeleton, degrees of saturation and types of functional groups, and vapor pressure parameter, appear to play a role in determining toxicities of the test monoterpenoids to stable flies. Global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment justify further studies on Z. piperitum and Z. armatum oil-derived materials as potential insecticides for the control of stable fly populations. PMID:23025190

  7. Efficacy of the entomopathogenic fungi Metarhizium anisopliae in the control of infestation by stable flies Stomoxys calcitrans (L.), under natural infestation conditions.

    Science.gov (United States)

    Cruz-Vazquez, C; Carvajal Márquez, J; Lezama-Gutiérrez, R; Vitela-Mendoza, I; Ramos-Parra, M

    2015-09-15

    The objective of this study was to evaluate the efficacy of an isolate of Metarhizium anisopliae applied by aspersion to control of Stomoxys calcitrans flies in dairy cattle naturally infested. Was applied by aspersion an aqueous formulation of M. anisopliae sensu lato (Ma134), at a concentration of 1×10(8)conidia/ml, four times with seven day intervals, on a group of eight Holstein cows; a control group of eight Holstein cows, received a water solution with Tween 80 (0.1%). The average number of flies per animal was estimated one day before each application, and then daily counts were done in both groups. The effectiveness of the formulation was calculated using the Abbott's formula. At the same time, defensive behaviors of stamp/kicks and tail movements were evaluated daily, estimating relative frequency per hour. The Ma134 formulation had an infestation control efficacy of 73%, taking into consideration the four study weeks. The population reduction effect was observed since the first week post-application (p<0.05), and the effect increased with the subsequent applications. Defensive behaviors were reduced beginning from the first application, reaching a reduction of 66% and 70%, respectively, during the four weeks of study. These results demonstrated the effectiveness of the formulation to control infestation by S. calcitrans, as well as reduce defensive behaviors which involves the infestation. PMID:26209932

  8. Kuidas ennast ise juhtida / Susanne Paulsen

    Index Scriptorium Estoniae

    Paulsen, Susanne

    2009-01-01

    Rosenecki biotagasiside-eksperdid õpetavad, kuidas inimene võib oma keha üksnes tahtejõu abil mõjutada. Aju-arvuti-liidese kaudu on võimalik mõjutada selliseid haigusi nagu hüperaktiivsus, epilepsia ja migreen

  9. Activity and relative abundance of hymenopterous parasitoids that attack puparia of Musca domestica and Stomoxys calcitrans (Diptera: Muscidae) on confined pig and cattle farms in Denmark

    DEFF Research Database (Denmark)

    Skovgård, H; Jespersen, J B

    1999-01-01

    A survey was conducted on 84 pig and cattle farms in Denmark between August and October 1996 and 1997. The aim was to describe the activity and relative abundance of parasitoids (Hymenoptera: Pteromalidae and Ichneumonidae) that attack puparia of Musca domestica Linnaeus and Stomoxys calcitrans...... (Linnaeus). In total, seven pteromalid species were recovered: Spalangia cameroni Perkins, S. nigripes Curtis, S. subpunctata Förster, Muscidifurax raptorGirault & Sanders, Pachycrepoideus vindemiae (Rondani), Urolepis rufipes(Ashmead) and Nasonia vitripennis (Walker), an ichneumonid Phygadeuon fumator......Gravenhorst, a diapriid Trichopria sp., and a staphylinid Aleocharasp. This is the first time that U. rufipes has been recorded in Europe. Spalangia cameroni and M. raptor were the most frequently recorded species in all regions of the country, and accounted for the main parasitism of Musca domesticaand Stomoxys...

  10. Diversity of Stomoxys spp. (Diptera: Muscidae) and diurnal variations of activity of Stomoxys indicus and S. calcitrans in a farm, in Wang Nam Khiao District, Nakhon Ratchasima Province, Thailand.

    Science.gov (United States)

    Keawrayup, S; Duvallet, G; Sukonthabhirom, S; Chareonviriyaphap, T

    2012-08-01

    A study of species diversity of Stomoxys spp. and diurnal variations of activity of the most abundant was performed during a one year period at a local dairy cattle farm in Wang Nam Khiao District, Nakhon Ratchasima Province, Thailand. Four species of stomoxyine flies were morphologically identified, including Stomoxys indicus Picard 1908, S. calcitrans (Linnaeus 1758), S. sitiens Rondani 1873 and S. uruma Shinonaga and Kanao 1966. The most common species were S. indicus (50.2%) and S. calcitrans (49.5%). S. sitiens and S. uruma were found in small proportions (flies captured was significantly different among the three seasons with the greatest number in the rainy season (mean = 66%; df = 2, P fly behavior, especially the daily flight activity, can assist in prioritization and design of appropriate vector prevention and control strategies. PMID:22910668

  11. Ocorrência de Spalangia endius Walker, 1839 (Hymenoptera, Pteromalidae em pupas de Musca domestica L. e Stomoxys calcitrans L. (Diptera, Muscidae no sul do Rio Grande do Sul

    Directory of Open Access Journals (Sweden)

    R.K Brandão

    2011-02-01

    Full Text Available It was reported the occurrence of Spalangia endius Walker, 1839 (Hymenoptera, Pteromalidae as a parasitoid of pupae of Musca domestica Linnaeus, 1758 (Diptera, Muscidae and Stomoxys calcitrans Linnaeus, 1758 (Diptera, Muscidae in the extreme Southern of Brazil. The collection of pupae was performed in January and February, 2008. The pupae of M. domestica and S. calcitrans were collected from bovine feces using the flotation method. The pupae were individualized in glass tubes and maintained in acclimatized chamber at 27±2ºC with relative air humidity > 70% until the emergence of the flies or the parasitoids. The referred occurrence consists in the first report to Rio Grande do Sul.

  12. 旋链角毛藻和中肋骨条藻间的他感作用%Allelopathic effects between Chaetoceros curvisetus and Skeletonema costatum

    Institute of Scientific and Technical Information of China (English)

    张议文; 王江涛

    2012-01-01

    选择两种常见硅藻——中肋骨条藻(Skeletonema costatum)和旋链角毛藻(Chaetoceros curvisetus)为研究对象,采用滤液培养的方法考察二者之间的他感效应,结果表明:f/2全营养培养条件下,旋链角毛藻指数后期无藻细胞滤液对中肋骨条藻的生长有显著抑制作用,抑制率随旋链角毛藻滤液比例的增大而增大,他感效应随作用时间消退后,中肋骨条藻生长速率提高,且随着旋链角毛藻滤液比例的增大,中肋骨条藻的细胞粒径有减小的趋势;中肋骨条藻指数后期无藻细胞滤液对旋链角毛藻的生长速率和细胞粒径均无影响,表明中肋骨条藻对旋链角毛藻无他感作用.本实验结果可为下一步提取他感物质、研究他感作用机理提供实验基础.%The two common types of diatom, respectively Chaetoceros curvisetus and Skeletonema costatum, were chosen to observe and study the allelopathic effect between them by means of cell-free filtrate culture. The observation showed that under the condition of enriched , cell-free filtrate of the C. curvisetus culture inhibited the growth of 5. costatum significantly in the later exponential growth phase. The inhibition rate was related to the proportion of C. curvisetus cell-free filtrate in the culture, in addition the diameter of S. costatum was affected as well. Allelochemical degraded as time went on, and then the relative growth rate of 5. costatum was increased. There was no influence on the relative growth rate and diameter of S. costatum by enriched C. cumsetus cell-free Citrate in the end of exponential growth phase, which showed that there was not allelopathic effect of S. costatum on C. curuisetus. The results provided the experimental basis for extracting allelochemical and researching allelopathic mechanism later.

  13. Evaluation of genotoxic responses of Chaetoceros tenuissimus and Skeletonema costatum to water accommodated fraction of petroleum hydrocarbons as biomarker of exposure.

    Science.gov (United States)

    Desai, S R; Deasi, S R; Verlecar, X N; Ansari, Z A; Jagtap, T G; Sarkar, A; Vashistha, Deepti; Dalal, S G

    2010-04-01

    Genotoxic responses towards chronic exposure of Chaetoceros tenuissimus and Skeletonema costatum to water accommodated fraction of petroleum hydrocarbons (WAF-P) were evaluated as biomarkers of petroleum hydrocarbons pollution. The DNA damage caused by water accommodated fraction of petroleum hydrocarbons was assessed in terms of the DNA integrity measured by alkaline unwinding assay. The comparative study of the growth pattern of C. tenuissimus with respect to DNA integrity and the DNA strand breaks in different concentrations of WAF-P showed sufficient tolerance. However, its toxicity increased proportionately with exposure to elevated levels of WAF-P. Although DNA damage in S. costatum was similar to C. tenuissimus, its tolerance level to WAF-P was at least 5 times lower than that of C. tenuissimus indicating its high sensitivity to petroleum hydrocarbons. Active growth was exhibited by C. tenuissimus between 10 and 20% WAF-P (ranging from 0.59 to 1.18mg/L petroleum hydrocarbons) which can be related to the polluted regions only, suggesting the tolerant nature of this organism. Considering the degree of sensitivity to petroleum products and good growth under laboratory conditions, these two diatoms could be recommended as model species for evaluating ecogenotoxic effects of wide range of petroleum hydrocarbon pollutants using alkaline unwinding assays. PMID:20096916

  14. Isolation and characterization of a single-stranded DNA virus infecting the marine diatom Chaetoceros sp. strain SS628-11 isolated from western Japan.

    Directory of Open Access Journals (Sweden)

    Kei Kimura

    Full Text Available Diatoms are significant organisms for primary production in the earth's aquatic environment. Hence, their dynamics are an important focus area in current studies. Viruses are a great concern as potential factors of diatom mortality, along with other physical, chemical, and biological factors. We isolated and characterized a new diatom virus (Csp07DNAV that lyses the marine planktonic diatom Chaetoceros sp. strain SS628-11. This paper examines the physiological, morphological, and genomic characteristics of Csp07DNAV. The virus was isolated from a surface water sample that was collected at Hiroshima Bay, Japan. It was icosahedral, had a diameter of 34 nm, and accumulated in the nuclei of host cells. Rod-shaped virus particles also coexisted in the host nuclei. The latent period and burst size were estimated to be <12 h and 29 infectious units per host cell, respectively. Csp07DNAV had a closed circular single-stranded DNA genome (5,552 nucleotides, which included a double-stranded region and 3 open reading frames. The monophyly of Csp07DNAV and other Bacilladnavirus group single-stranded DNA viruses was supported by phylogenetic analysis that was based on the amino acid sequence of each virus protein. On the basis of these results, we considered Csp07DNAV to be a new member of the genus Bacilladnavirus.

  15. Biological control of house flies Musca domestica and stable flies Stomoxys calcitrans(Diptera: Muscidae) by means of inundative releases of Spalangia cameroni(Hymenoptera: Pteromalidae).

    Science.gov (United States)

    Skovgård, H; Nachman, G

    2004-12-01

    The efficacy of the pupal parasitoid Spalangia cameroni Perkins as a biological control agent was tested against house flies Musca domestica Linnaeus and stable flies Stomoxys calcitrans (Linnaeus) in one dairy cattle and two pig installations in Denmark. Weekly releases of S. cameroni from April through to September-October 1999 and 2000 resulted in significant suppressions of house fly populations to below nuisance level, whereas no effect on stable flies was found. Parasitism was significantly higher in the release years compared to the control years, but was below 25% averaged over the fly season for each farm. A statistical model based on a functional relationship between the innate capacity of increase of the two fly species and three explanatory variables (air temperature, fly density and parasitism) provided a fairly good fit to data with the abundances of house flies and stable flies explained mostly by temperature, but intra- and interspecific competition, and parasitism had a significant effect as well. Overall, the model was capable of explaining 14% and 6.6% of the total variation in data for house fly and stable fly, respectively. Spalangia cameroni was the predominant parasitoid to emerge from exposed house fly pupae, but from mid summer onwards Muscidifurax raptor Girault & Sanders (Hymenoptera: Pteromalidae) was also quite common. The study indicated that biological control of house flies can be an efficient alternative to chemical control. PMID:15541194

  16. Interaction Effects of Light, Temperature and Nutrient Limitations (N, P and Si on Growth, Stoichiometry and Photosynthetic Parameters of the Cold-Water Diatom Chaetoceros wighamii.

    Directory of Open Access Journals (Sweden)

    Kristian Spilling

    Full Text Available Light (20-450 μmol photons m(-2 s(-1, temperature (3-11 °C and inorganic nutrient composition (nutrient replete and N, P and Si limitation were manipulated to study their combined influence on growth, stoichiometry (C:N:P:Chl a and primary production of the cold water diatom Chaetoceros wighamii. During exponential growth, the maximum growth rate (~0.8 d(-1 was observed at high temperature and light; at 3 °C the growth rate was ~30% lower under similar light conditions. The interaction effect of light and temperature were clearly visible from growth and cellular stoichiometry. The average C:N:P molar ratio was 80:13:1 during exponential growth, but the range, due to different light acclimation, was widest at the lowest temperature, reaching very low C:P (~50 and N:P ratios (~8 at low light and temperature. The C:Chl a ratio had also a wider range at the lowest temperature during exponential growth, ranging 16-48 (weight ratio at 3 °C compared with 17-33 at 11 °C. During exponential growth, there was no clear trend in the Chl a normalized, initial slope (α* of the photosynthesis-irradiance (PE curve, but the maximum photosynthetic production (P(m was highest for cultures acclimated to the highest light and temperature. During the stationary growth phase, the stoichiometric relationship depended on the limiting nutrient, but with generally increasing C:N:P ratio. The average photosynthetic quotient (PQ during exponential growth was 1.26 but decreased to <1 under nutrient and light limitation, probably due to photorespiration. The results clearly demonstrate that there are interaction effects between light, temperature and nutrient limitation, and the data suggests greater variability of key parameters at low temperature. Understanding these dynamics will be important for improving models of aquatic primary production and biogeochemical cycles in a warming climate.

  17. A comparison of morphological and molecular-based surveys to estimate the species richness of Chaetoceros and Thalassiosira (bacillariophyta, in the Bay of Fundy.

    Directory of Open Access Journals (Sweden)

    Sarah E Hamsher

    Full Text Available The goal of this study was to compare the ability of morphology and molecular-based surveys to estimate species richness for two species-rich diatom genera, Chaetoceros Ehrenb. and Thalassiosira Cleve, in the Bay of Fundy. Phytoplankton tows were collected from two sites at intervals over two years and subsampled for morphology-based surveys (2010, 2011, a culture-based DNA reference library (DRL; 2010, and a molecular-based survey (2011. The DRL and molecular-based survey utilized the 3' end of the RUBISCO large subunit (rbcL-3P to identify genetic species groups (based on 0.1% divergence in rbcL-3P, which were subsequently identified morphologically to allow comparisons to the morphology-based survey. Comparisons were compiled for the year (2011 by site (n = 2 and by season (n = 3. Of the 34 taxa included in the comparisons, 50% of taxa were common to both methods, 35% were unique to the molecular-based survey, and 12% were unique to the morphology-based survey, while the remaining 3% of taxa were unidentified genetic species groups. The morphology-based survey excelled at identifying rare taxa in individual tow subsamples, which were occasionally missed with the molecular approach used here, while the molecular methods (the DRL and molecular-based survey, uncovered nine cryptic species pairs and four previously overlooked species. The last mentioned were typically difficult to identify and were generically assigned to Thalassiosira spp. during the morphology-based survey. Therefore, for now we suggest a combined approach encompassing routine morphology-based surveys accompanied by periodic molecular-based surveys to monitor for cryptic and difficult to identify taxa. As sequencing technologies improve, molecular-based surveys should become routine, leading to a more accurate representation of species composition and richness in monitoring programs.

  18. Impact of elevated CO2 concentrations on the growth and ultrastructure of non-calcifying marine diatom (Chaetoceros gracilis F.Schütt

    Directory of Open Access Journals (Sweden)

    Hanan M. Khairy

    2014-01-01

    Full Text Available The impacts of different CO2 concentrations on the growth, physiology and ultrastructure of noncalcifying microalga Chaetoceros gracilis F.Schütt (Diatom were studied. We incubated Ch. gracilis under different CO2 concentrations, preindustrial and current ambient atmospheric concentrations (285 and 385 μatm, respectively or predicted year-2100 CO2 levels (550, 750 and 1050 μatm in continuous culture conditions. The growth of Ch. gracilis measured as cell number was decreased by increasing the pCO2 concentration from nowadays concentration (385 μatm to 1050 μatm. The lowest percentage changes of oxidizable organic matter, nitrite, nitrate, phosphate and silicate were recorded at a higher pCO2 (1050 μatm, and this is in consistence with the lowest recorded cell number indicating unsuitable conditions for the growth of Ch. gracilis. The minimum cell numbers obtained at higher levels of CO2 clearly demonstrate that, low improvement occurred when the carbon level was raised. This was confirmed by a highly negative correlation between cell number and carbon dioxide partial pressure (r = −0.742, p ⩽ 0.05. On the other hand, highest growth rate at pCO2 = 385 μatm was also confirmed by the maximum uptake of nutrient salts (NO3 = 68.96 μmol.l−1, PO4 = 29.75 μmol.l−1, Si2O3 = 36.99 μmol.l−1. Total protein, carbohydrate and lipid composition showed significant differences (p ⩽ 0.05 at different carbon dioxide concentrations during the exponential growth phase (day 8. Transmission Electron Microscopy of Ch. gracilis showed enlargement of the cell, chloroplast damage, disorganization and disintegration of thylakoid membranes; cell lysis occurs at a higher CO2 concentration (1050 μatm. It is concluded from this regression equation and from the results that the growth of Ch. gracilis is expected to decrease by increasing pCO2 and increasing ocean acidification.

  19. Effect of alternative mediums on production and proximate composition of the microalgae Chaetoceros muelleri as food in culture of the copepod Acartia sp. Efecto de medios alternativos sobre la producción y composición proximal de la microalga Chaetoceros muelleri como alimento en cultivo del copépodo Acartia sp.

    Directory of Open Access Journals (Sweden)

    Luis R Martínez-Córdova

    2012-03-01

    Full Text Available Microalgae Chaetoceros muelleri was cultured in three different mediums consisting on an agricultural fertilizer (Agr-F, aquacultural fertilizer (Aq-F and a conventional medium (F/2, control. These microalgae were later used as natural food to culture the copepod Acartia sp. The productive response and chemical proximate composition of microalgae and copepods were monitored. Growth rate and final cell concentration were higher in microalgae cultured in Agr-F compared to the control. In addition, the final biomass and cellular concentration were also the highest in Agr-F. Microalgae from Agr-F and Aq-F had higher carbohydrate and lower protein contents than those in the control. No differences in lipid and ash contents were observed. Regarding copepod production, higher densities and fecundity indexes were observed for those fed with microalgae previously cultured in Agr-F and Aq-F, compared to the control. The adult-nauplii ratio was also higher in copepods fed on microalgae from Agr-F compared to Aq-F and control. Copepods fed on Agr-F and Aq-F microalgae, had higher protein content compared to those fed on control microalgae; carbohydrates were higher in copepods fed on Agr-F as compared to Aq-F microalgae. No differences in lipid and ash contents were registered. Agr-F and Aq-F were adequate alternative mediums to produce C. muelleri, which produced higher quality microalgae that increased the copepod production.La microalga Chaetoceros muelleri fue cultivada en tres medios diferentes basados en un fertilizante agrícola (Agr-F, un fertilizante acuícola (Aq-F y un medio convencional (F/2, control. Éstas microalgas fueron posteriormente utilizadas como alimento natural para cultivar el copépodo Acartia sp. La respuesta productiva y la composición proximal de las microalgas y copépodos fueron monitoreadas. La tasa de crecimiento y concentración final de células fueron mayores en la microalga cultivada en Agr-F, comparada con el control

  20. Control Químico de la Mosca de los Establos, Stomoxys Calcitrans (L y Otros Insectos Asociados con Estipes de Palma Africana en Descomposición

    Directory of Open Access Journals (Sweden)

    Ureta Sandino Eduardo

    1972-12-01

    Full Text Available En ensayos para determinar el efecto del diazinon 1% I.A. (ingrediente activo; bromophos 1 % I.A.; dieldrin 0.5% I.A., 2% I.A. y methomyl 0.1 % I.A. sobre larvas de Stomoxys calcilrans y otros insectos asociados con tipes de palma africana (Elaeis guineensis en descomposición, se encontró que los tratamientos con diazinon 1% I.A. y bromophos 1% I.A. fueron los más efectivos para impedir la proliferación en éstos de las larvas de Slomoxys calcilralls. Ambos insecticidas protegieron eficientemente los estipes por lo menos durante dos semanas. El dieldrin al 0.5% I. A. y 2% I. A., aunque inferior al bromophos 1% I.A. y al diazinon 1% I.A. también fue efectivo para impedir la proliferación de larvas de la mosca en los troncos de palma africana en descomposición. El tratamiento con methomyl 0.1 % I. A. al parecer no impidió la multiplicación de las larvas en los estipes, según pudo observarse en muestras tomadas a las dos semanas de haber sido aplicado el producto. El diazinon 1% I.A: bromophos 1 % I.A.; dieldrin 0.5% I.A. y 2% I.A., aparentemente fueron eficaces para controlar los adultos de Limnobaris calandriformis y Metamasius hemipterus, los cuales eran atraídos en grandes cantidades a los trozos de tallo de palma recién rajada, así como también impidieron la proliferación en éstos de las larvas de los dípteros Ormidea obesa y Hermelia sp./Abstract Several tests were carried out to determine the effectiveness of diazinon 1% I.A., bromophos 1% I.A., dieldrin 0.5 and 2% I.A., and methomyl 0.1 % on larvae of the stable fly, Stomoxys calcitrans, and other insects associated with dead trunks of the oil palm (Elaeis guineesis.The results showed by the author indicate that diazinon and bromophos were the most effective materials tested. Both insecticides protected well the dead trunks for at least two weeks. Dieldrin (both doses although less efficient than diazinon, was also effective in preventing the development of great numbers of

  1. Comparison of acute toxicity of process chemicals used in the oil refinery industry, tested with the diatom Chaetoceros gracilis, the flagellate Isochrysis galbana, and the zebra fish, Brachydanio rerio

    International Nuclear Information System (INIS)

    Chemicals under the trade names Nalco 537-DA, Nalco 625, Nalco 7607, Nalco 5165, Ivamin, and technical monoethanolamine are used extensively in the oil refinery industry. Aquatic toxicity tests were conducted using zebra fish fry (Brachydanio rerio) and the unicellular algae Isochrysis galbana (a flagellate) and Chaetoceros gracilis (a diatom). Inhibition of cell division, chlorophyll content, and 14CO2 uptake in the algae were sensitive end points. The effective concentrations (EC50s) of growth inhibition were 0.1 mg/L (Ivamin; I. galbana), 0.8 mg/L (Nalco 7607; I. galbana), 6 mg/L (Nalco 625; I. galbana), 10 mg/L (Nalco 5165; C. gracilis), and 15 mg/L (Nalco 537-DA; C. gracilis). The lethal concentrations (LC50s) (96 h) toward zebra fish fry was 1 mg/L for Nalco 7607, 6.5 mg/L for Nalco 537-DA, 7.1 mg/L for Nalco 625, and 20 mg/L for Ivamin 803. Monoethanolamine had an LC50 higher than 5,000 mg/L. Nalco 5165 was not tested on fish fry. The heartbeat frequency of fish embryos was reduced by 2.5 mg/L Nalco 537-DA, but this was an insensitive end point for the other chemicals

  2. Toxicity of lead and cadmium to tropical marine phytoplankton

    DEFF Research Database (Denmark)

    Jensen, Susanne Dal; Panutrakul, Suwanna; Nyholm, Niels

    2000-01-01

    Toxicity of Pb and Cd to three tropical, marine phytoplankton species isolated from the Andaman Sea off Phuket Thailand were determined. The phytoplankton species included one diatom, Chaetoceros calcitrans, one green alga, Chlorella sp., and one chrysophyte, Dunaliella tertiolecta. The test method...

  3. Évaluation de la toxicité de pesticides sur quatre niveaux trophiques marins : microalgues, échinoderme, bivalves et poisson

    OpenAIRE

    Amara, Anis

    2012-01-01

    This work aims to study the effects of a few pesticides and one adjuvant on marine organisms, representatives of four trophic levels : micro-algae, echinoderm, bivalves and fish. Analysis of the pollu-sensitivity was based on the utilisation of existing bio-assays or adapted to this study.Phytotoxic assessments were conducted on three phytoplanktonic species (Chaetoceros calcitrans, Isochrysis aff. Galbana et Tetraselmis suecica) using the fungicide epoxiconazole and the adjuvant nonylphenol....

  4. Growth and survival larvae of Argopecten nucleus fed with different microalgae diets

    Directory of Open Access Journals (Sweden)

    Yenia Katerine Carreño Hernández

    2012-06-01

    Full Text Available The influence of the diet on larval growth of the scallops Argopecten nucleus was studied, testing six microalgae diets composed by single-algae and mixed diets of the species Isochrysis galbana, Chaetoceros calcitrans y Tetraselmis suecica, handling a concentration per mL equivalent to 40000 cells of I. galbana and the response through the variables surviving, growth, appearance of the eye spot and state of condition (full, half-full and empty larvae was measured. The diets containing I. galbana showed greater results over all the measured variables, with regard to those where it was not present. In particular, the mixed diet I. galbana + C. calcitrans presented superiority over all variables, although in the most cases was statistically similar to I. galbana + C. calcitrans + T. suecica, I. galbana + T. suecica and I. galbana alone. For the opposite, the diets with the lowest results were C. calcitrans and C. calcitrans +T. suecica. The results obtained are principally attributed to the nutritional composition mainly of high unsaturated fatty acids (HUFA of each microalgae and each mixture supply, which is discussed in detail.

  5. Mercury-induced genotoxicity in marine diatom (Chaetoceros tenuissimus)

    Digital Repository Service at National Institute of Oceanography (India)

    Sarker, S.; Desai, S.R.; Verlecar, X.N.; Sarker, M.S.; Sarkar, A.

    . tenuissimus cells. Grover et al. (2001) observed similar repair of DNA damage in rat peripheral blood leucocytes at an HgCl2 level of 43.2 ng g −1 after a 48-h exposure period. It was previously shown that, when phytoplankton was exposed to heavy metals... correlation between the metal concentration in water and plankton growth (Senthilnathan and Balasubramanian 1999). Interestingly, an inhibition was observed in cell population and chlorophyll a (chl a) concen- tration in Dunaliella minuta when exposed...

  6. Evolution of phytoplankton cultures after ultraviolet light treatment

    International Nuclear Information System (INIS)

    Introducing invasive species in new environments through ballast water is a specific problem of contamination and has recently become one of the main concerns of Maritime Organizations. Ultraviolet-C radiation (UV-C) is a technological alternative to prevent this maritime pollution. This study addresses the effect of UV-C on different phytoplankton cultures and also the ability to recover following exposure to damage. A UV-C low-pressure lamp irradiates the cultures. The distance from the source and the thickness of the layer prevent part of the energy from reaching the culture and the disinfective process is diminished. Some cultures such as Chlorella autotrophica and Chaetoceros calcitrans can easily recover from UV-C damage. However, Phaeocystis globosa does not have this ability. C. calcitrans forms cysts and exhibits two different behaviours depending on the dose applied.

  7. Interactive effect of elevated pCO2 and temperature on the larval development of an inter-tidal organism, Balanus amphitrite Darwin (Cirripedia: Thoracica)

    Digital Repository Service at National Institute of Oceanography (India)

    Baragi, L.V.; Anil, A.C.

    of the suitable food type (Barnes and Barnes, 1958). The growth rate of an organism is also influenced by the food quality and quantity (Moyse, 1963). Several studies have reported that the rising pCO2/reduced pH change the nutritional quality (Burkhardt et al... on the nutritional quality of the diatom (Chaetoceros calcitrans) which is used as feed for the rearing of barnacle larvae. In this experiment the growth of this diatom was measured in terms of cell numbers; and the nutritional quality was measured in terms...

  8. Stable isotopic analysis of Barnacle larvae and their faecal pellets to evaluate the ingested food

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.A.; Anil, A.C.

    ). 15N enrichment in the laboratory reared larvae fed with Chaetoceros calcitrans diet was about 1.42‰ which was slightly lower. Though the δ15N ratios of the consumers are known to be heavier by about 3-4‰ than their presumed diet (Michener... and Schell, 1994), the laboratory experiments have shown lower trophic enrichment values for 15N, with mean differences in δ15N between diet and their consumers being lower in marine (1.48‰) than in freshwater (2.82‰) organisms (Vanderklift and Ponsard...

  9. Invention of outdoor closed type photobioreactor for microalgae

    International Nuclear Information System (INIS)

    For efficient mass production of microalgae, we invented a novel photobioreactor that uses aeration for mixing. To select better chamber shapes for a photobioreactor, two aspects of its performance were numerically simulated, mixing and light reception. Two shapes survived the computational filters and were tested by cultivating Chlorococum littorale. One of them attained 20.5 g/m2/day in dry weight in the winter days in Japan. Recently, this figure was overwritten by the performance of 37.3 g/m2/day for Chaetoceros calcitrans with the maximum cell density of 2.5 g/L

  10. Caregivers' experiences of the South African judicial system after the reporting of child sexual abuse / N.L. Paulsen.

    OpenAIRE

    Paulsen, Nicole

    2013-01-01

    Child sexual abuse (CSA) is found to occur in alarming proportions worldwide. In South Africa, children represent almost half of the victims of known sexual abuse, and this is becoming a great concern, even being described as a silent epidemic. This alarming fact as well as the researcher’s experiences as a social worker in this field, resulted in her reviewing literature, in order to gain further insight into the current situation in South Africa. It was discovered that the number of success...

  11. Phytochemical screening of twelve species of phytoplankton isolated from Arabian Sea coast

    Directory of Open Access Journals (Sweden)

    Sushanth Vishwanath Rai

    2015-11-01

    Full Text Available Objective: To analyze the phytochemicals in twelve species of marine phytoplankton. Methods: Total phenolic content of methanol extract was estimated by the Folin-Ciocalteu method. Total flavonoid content of the methanol extarct was determined by aluminium chloride method. Chlorophylls, β-carotene and astaxanthin were estimated by acetone extraction method. Vitamin C was determined by dinitrophenyl-hydrazine method. Phycobiliproteins such as allophycocyanin, phycocyanin and phycoerythrin in the aqueous extracts were determined. Results: Total phenolics varied from 5.41 mg gallic acid equivalents/g dry weight (DW in Phormidium corium (P. corium to 17.37 mg gallic acid equivalents/g DW in Oscillatoria fremyii (O. fremyii. Total flavonoids ranged between 0.74 mg quercetin equivalent/g DW in P. corium and 9.87 mg quercetin equivalent/g DW in Nannochloropsis oceanica. Chlorophyll-a pigment was high in Chaetoceros calcitrans (C. calcitrans (15.51 mg/g DW and low in P. corium (1.08 mg/g DW. Chlorophyll-c ranged between 0.07 mg/g DW in Nannochloropsis oceanica and 4.62 mg/g DW in C. calcitrans. High contents of β-carotene and astaxanthin were found in C. calcitrans and low in P. corium which ranged from 0.33 to 10.03 mg/g DW and 0.18 to 3.85 mg/g DW, respectively. Vitamin C content varied from 0.50 mg/g DW in C. calcitrans to 1.51 mg/g DW in Phormidium tenue. O. fremyii showed highest total phycobiliproteins of 317.05 mg/g DW. High contents of allophycocyanin and phycocyanin were found in O. fremyii, whereas high contents of phycoerythrin were found in Oscillatoria sancta. All the three phycobiliproteins were low in Chroococcus turgidus. Conclusions: Marine phytoplankton are one of the natural sources providing novel biologically active compounds with potential for pharmaceutical applications.

  12. Effect of sonication frequency on the disruption of algae.

    Science.gov (United States)

    Kurokawa, Masaki; King, Patrick M; Wu, Xiaoge; Joyce, Eadaoin M; Mason, Timothy J; Yamamoto, Ken

    2016-07-01

    In this study, the efficiency of ultrasonic disruption of Chaetoceros gracilis, Chaetoceros calcitrans, and Nannochloropsis sp. was investigated by applying ultrasonic waves of 0.02, 0.4, 1.0, 2.2, 3.3, and 4.3MHz to algal suspensions. The results showed that reduction in the number of algae was frequency dependent and that the highest efficiency was achieved at 2.2, 3.3, and 4.3MHz for C. gracilis, C. calcitrans, and Nannochloropsis sp., respectively. A review of the literature suggested that cavitation, rather than direct effects of ultrasonication, are required for ultrasonic algae disruption, and that chemical effects are likely not the main mechanism for algal cell disruption. The mechanical resonance frequencies estimated by a shell model, taking into account elastic properties, demonstrated that suitable disruption frequencies for each alga were associated with the cell's mechanical properties. Taken together, we consider here that physical effects of ultrasonication were responsible for algae disruption. PMID:26964936

  13. The culture of pearl oysters, Pinctada fucata (Gould, 1850 in Phuket with temperature shock method and survival rates on various feeds

    Directory of Open Access Journals (Sweden)

    Rativat, V.

    2005-02-01

    Full Text Available Marine pearl farming at Phuket Island has exploited natural pearl oysters. In order to obtain sufficient pearl oysters, Pinctada fucata (Gould, 1850, the oyster cultivation was carried out to determine appropriate kinds of food and types of spat collectors. The male and female oysters were stimulated to spawn with this temperature shock method (treated with 32ºC and then with 26ºC. The fertilized eggs developed into the stages of polar body, cleavage, blastula, gastrula, trochophore and then D-shape larvae. At the ageof 19-26 hrs. the larvae were fed with three kinds of food: Isochrysis galbana, Chaetoceros calcitrans and the mixture of 1:1 I. galbana and C. calcitrans. Upon the first 30 days, shell lengths of the spats fed with I. Galbana, C. calcitrans and the mixture were 422.00±59.32, 221.33±12.46 and 347.33±67.98 μg, respectively. The 26-29th day spat stage settled to the collectors: saran net, plastic plates and wavy tile. Number of spats settling to saran net was the highest. But after being moved into the sea for 30 days, the survival rate was89.06% which was lower than for those settling to plastic plates (93.29% and wavy tile (93.99%.

  14. Effects of iron limitation on photosynthesis and carbohydrate metabolism in the Antarctic diatom Chaetoceros brevis (Bacillariophyceae)

    NARCIS (Netherlands)

    van Oijen, T; van Leeuwe, MA; Gieskes, WWC; de Baar, HJW

    2004-01-01

    Iron, one of the structural elements of organic components that play an essential role in photosynthesis and nitrogen assimilation of plants, is available at extremely low concentrations in large parts of the Southern Ocean's surface waters. We tested the hypothesis that photosynthesis is the primar

  15. Genotoxicity of cadmium in marine diatom Chaetoceros tenuissimus using the alkaline Comet assay

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, S.R.; Verlecar, X.N.; Nagarajappa; Goswami, U.

    /L and 12th day at 7.5 mg/L concentrations. At lower Cd concentrations (4.5 mg/L and below) the damage was below 30% till the last day. This suggested that higher Cd levels have early damaging effects on cell nuclear material and that % injury increases...

  16. Lipid extraction methods from microalgal biomass harvested by two different paths: screening studies toward biodiesel production.

    Science.gov (United States)

    Ríos, Sergio D; Castañeda, Joandiet; Torras, Carles; Farriol, Xavier; Salvadó, Joan

    2013-04-01

    Microalgae can grow rapidly and capture CO2 from the atmosphere to convert it into complex organic molecules such as lipids (biodiesel feedstock). High scale economically feasible microalgae based oil depends on optimizing the entire process production. This process can be divided in three very different but directly related steps (production, concentration, lipid extraction and transesterification). The aim of this study is to identify the best method of lipid extraction to undergo the potentiality of some microalgal biomass obtained from two different harvesting paths. The first path used all physicals concentration steps, and the second path was a combination of chemical and physical concentration steps. Three microalgae species were tested: Phaeodactylum tricornutum, Nannochloropsis gaditana, and Chaetoceros calcitrans One step lipid extraction-transesterification reached the same fatty acid methyl ester yield as the Bligh and Dyer and soxhlet extraction with n-hexane methods with the corresponding time, cost and solvent saving. PMID:23434816

  17. Photosynthetic characteristics of five high light and low light exposed microalgaea as measured with 14C-uptake and oxygen electrode techniques

    OpenAIRE

    Grobbelaar, J.U.; Schanz, F.; Dubinsky, Z.; M. M. Tilzer; Burger-Wiersma, T; Rijkeboer, M.; Lemoalle, Jacques; Falkowski, P. G.

    1992-01-01

    #Tetraselmis suecica$, #Thalassiosira pseudonana$, #Chaetoceros calcitrans$, #Isochrysis galbana$ et #Microcystis sp.$ ont été utilisées pour déterminer leurs capacités d'adaptation et pour tester les différences entre les deux méthodes de mesure. Les cultures avaient été exposées à un éclairement fort (HL) ou à un éclairement faible (LL) pendant deux jours avant l'expérience. L'efficacité de la conversion de la lumière (...) et l'activité photosynthétique spécifique maximale par unité de chl...

  18. Workshop on The Functional Analysis of Quantum Information Theory : a Collection of Notes Based on Lectures by Gilles Pisier, K. R. Parthasarathy, Vern Paulsen and Andreas Winter

    CERN Document Server

    Gupta, Ved Prakash; Sunder, V S

    2015-01-01

    This book provides readers with a concise introduction to current studies on operator-algebras and their generalizations, operator spaces and operator systems, with a special focus on their application in quantum information science. This basic framework for the mathematical formulation of quantum information can be traced back to the mathematical work of John von Neumann, one of the pioneers of operator algebras, which forms the underpinning of most current mathematical treatments of the quantum theory, besides being one of the most dynamic areas of twentieth century functional analysis. Today, von Neumann’s foresight finds expression in the rapidly growing field of quantum information theory. These notes gather the content of lectures given by a very distinguished group of mathematicians and quantum information theorists, held at the IMSc in Chennai some years ago, and great care has been taken to present the material as a primer on the subject matter. Starting from the basic definitions of operator space...

  19. Phytochemical screening of twelve species of phytoplankton isolated from Arabian Sea coast

    Institute of Scientific and Technical Information of China (English)

    Sushanth Vishwanath Rai; Madaiah Rajashekhar

    2015-01-01

    Objective:To analyze the phytochemicals in twelve species of marine phytoplankton. Methods: Total phenolic content of methanol extract was estimated by the Folin-Ciocalteu method. Total flavonoid content of the methanol extarct was determined by aluminium chloride method. Chlorophylls,β-carotene and astaxanthin were estimated by acetone extraction method. Vitamin C was determined by dinitrophenyl-hydrazine method. Phycobiliproteins such as allophycocyanin, phycocyanin and phycoerythrin in the aqueous extracts were determined. Results: Total phenolics varied from 5.41 mg gallic acid equivalents/g dry weight (DW) in Phormidium corium (P. corium) to 17.37 mg gallic acid equivalents/g DW inOscillatoria fremyii(O. fremyii). Total flavonoids ranged between 0.74 mg quercetin equivalent/g DW inP. corium and 9.87 mg quercetin equivalent/g DW inNannochloropsis oceanica. Chlorophyll-a pigment was high inChaetoceros calcitrans(C. calcitrans)(15.51 mg/g DW) and low inP. corium (1.08 mg/g DW). Chlorophyll-c ranged between 0.07 mg/g DW inNannochloropsis oceanica and 4.62 mg/g DW inC. calcitrans. High contents ofβ-carotene and astaxanthin were found inC. calcitrans and low inP. corium which ranged from 0.33 to 10.03 mg/g DW and 0.18 to 3.85 mg/g DW, respectively. Vitamin C content varied from 0.50 mg/g DW inC. calcitrans to 1.51 mg/g DW inPhormidium tenue.O. fremyii showed highest total phycobiliproteins of 317.05 mg/g DW. High contents of allophycocyanin and phycocyanin were found inO. fremyii, whereas high contents of phycoerythrin were found inOscillatoria sancta. All the three phycobiliproteins were low inChroococcus turgidus. Conclusions: Marine phytoplankton are one of the natural sources providing novel biologically active compounds with potential for pharmaceutical applications.

  20. The regrowth of phytoplankton cultures after UV disinfection

    International Nuclear Information System (INIS)

    Highlights: ► Phytoplankton cultures were placed in a rich medium after UV-C irradiation. ► Flow cytometry and PAM were used for determining cell viability. ► The behavior differs from that of cultures kept in their original environment. ► Chlorella autotrophica recovers between 5 and 10 days after the treatment. ► Phaeocystis globosa shows only a slight recovery for low-dose UV-radiation exposure. - Abstract: This study addresses how cultures of three phytoplankton species –Chaetoceros calcitrans, Chlorella autotrophica and Phaeocystis globosa – can recover from the effects of UV-C exposure if the cells are placed in a rich medium. Flow cytometry and pulse amplitude modulation (PAM) were used to determine cell recovery after UV treatment. The recovery of C. calcitrans was complete 9 days after treatment. For C. autotrophica, the recovery was noticeable 5 days after treatment. P. globosa only recovered if the UV dose did not exceed 7.3 × 105 μWs/cm2. The recovery of the UV-treated cultures introduced to a regrowth medium, compared with the recovery of the irradiated cultures kept in their original environment, had two main characteristics: cell recovery was slower but was more efficient. This pattern of recovery has very important implications for real ballast water management systems because such systems discharge treated water into the environment

  1. Efficiency of traps for Stomoxys calcitrans and Stomoxys niger niger on Reunion Island.

    Science.gov (United States)

    Gilles, J; David, J-F; Duvallet, G; De La Rocque, S; Tillard, E

    2007-03-01

    The main objective of this study was to compare the trapping efficiency of two Alsynite sticky traps (modified Williams and modified Broce) and two phtalogen blue cloth traps (Vavoua and Nzi) to be used in an integrated control programme of Stomoxys spp. (Diptera: Muscidae) on Reunion Island. Mean daily catches of these flies on two dairy farms differed significantly between the four types of trap. The Broce trap was the least efficient and had the lowest specificity for Stomoxys spp. The Vavoua, Nzi and Williams traps performed significantly better but could not be ranked on the basis of the numbers of Stomoxys caught because their respective performances differed between farms. Given the various practical criteria, it is concluded that, as control tools, blue cloth traps (Vavoua and Nzi) have practical advantages over the Williams trap. The Vavoua trap, which is less expensive and easier to use for farmers, seems adequate to complement other methods of fly control on Reunion Island. PMID:17373948

  2. Pollen recovered from the exoskeleton of stable flies, Stomoxys calcitrans (L.) in Gainesville, Florida

    Science.gov (United States)

    Stable flies are pestiferous blood feeding flies that attack animals and humans. Besides consuming blood, these flies will also visit flowers to take nectar meals. When feeding on nectar, flies become coated with pollen which can be used to identify flowers used by the flies. Recently, flies cove...

  3. Effects of iron availability on pigment signature and biogenic silica production in the coastal diatom Chaetoceros gracilis

    Digital Repository Service at National Institute of Oceanography (India)

    Biswas, H.; Bandyopadhyay, D.

    activated a strong photoprotection mechanism by maximising the conversion of diadinoxanthin to diatoxanthin and by increasing overall amount of photoprotective pigments relative to light harvesting pigments. The xanthophyll cycle comprising of diadinoxanthin...

  4. Contact and spatial repellency from catnip essential oil, Nepeta cataria, against stable fly, Stomoxys calcitrans, and other filth flies

    Science.gov (United States)

    Presenting brief summaries of our significant findings on: 1). Development of an in vitro bioassay for screening/discovering biting fly repellents, 2). Strong repellency found from catnip oil and its ingredient compounds, nepetalactones against four filth fly species; 3). Feeding deterrency, oviposi...

  5. Biogenic amines in the stable fly Stomoxys calcitrans L. (Diptera: Muscidae): tissue localization and roles in feeding and reproduction

    Science.gov (United States)

    Biogenic amines, such as serotonin (5-hdroxytryptamine [5-HT]) and octopamine (OA), play critical roles as neurotransmitters and neuromodulators that control or modulate many behaviors in insects, such as feeding and reproduction. Neurons immunoreactive (IR) to 5-HT and OA were detected in the centr...

  6. Filtration and respiration rates of the short-necked clam Paphia undulata (Born, 1778 (Mollusca, Pelecypoda: Veneridae under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Laureen Morillo Manalo

    2010-12-01

    Full Text Available The filtration and respiration rates of various size classes (35-39.99, 40-44.99,45-49.99, 50-54.99 and 55-59.99 mm of the short-necked clam Paphia undulata were measured in the laboratory. The effects of three light regimes (0 lux, 172.22 lux and 645.83 lux, three microalgal species (Isochrysis galbana, Tetraselmis tetrahele and Chaetoceros calcitrans and four microalgal concentrations (10, 25, 50 and 100 x 104 cells ml-1 on filtration rates were investigated. Mean filtration rate was highest (0.57 ± 0.04 Lh-1ind.-1 under total darkness. This can be attributed to the natural environment of this species which is characterized by silty substrate and low visibility. Filtration was also highest in the microalga Isochrysis galbana (0.67 ± 0.05. Rates initially increased from low to moderate microalgal concentrations (25 x 104 cells ml-1 and decreased at higher concentrations. Filtration generally decreased with increase in clam size. Light intensity, microalgal species and microalgal concentration showed significant effects on filtration. Respiration of fed clams was higher (0.138 ± 0.026 ml O2h-1ind.-1 than unfed clams (0.053± 0.025 ml O2h-1 nd.-1 and increased with clam size.

  7. Comparison of nitroethane, 2-nitro-1-propanol, lauric acid, Lauricidin and the Hawaiian marine algae, Chaetoceros, for potential broad-spectrum control of anaerobically grown lactic acid bacteria

    Science.gov (United States)

    The gastrointestinal tract of bovines often contains bacteria that contribute to disorders of the rumen and may also contain foodborne or opportunistic human pathogens as well as bacteria capable of causing mastitis in cows. Thus, there is a need to develop broad-spectrum therapies that are effecti...

  8. Evaluation of genotoxic responses of Chaetoceros tenuissimus and Skeletonema costatum to water accommodated fraction of petroleum hydrocarbons as biomarker of exposure

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, S.R.; Verlecar, X.N.; Ansari, Z.A.; Jagtap, T.G.; Sarkar, A.; Vashistha, D.; Dalal, S.G.

    their toxicity. Photo-oxidation is an important mechanism in this respect. Greatly increased toxicity has been reported to algae by photo- oxidised hydrocarbons (Lacaze and Viledonde, 1976; Skjoldal et al., 1982). Aromatic compounds get 13 readily photo... time. Because of the polar and the non-polar nature, they are concentrated more by organisms and have a deleterious effect on the cell membrane, which could lead to death of the cell (Larson et al., 1979). Thus, photo-oxidation products might have...

  9. In vitro comparison of nitroethane, 2-nitro-1-propanol, lauric acid, Lauricidin(R), and the Hawaiian marine algae, Chaetoceros, activity against anaerobically grown Staphylococcus aureus

    Science.gov (United States)

    Mastitis is a common illness of dairy cattle and is very costly, economically, to the dairy farmer. Thus, there is a need to develop broad-spectrum therapies that are effective while not leading to unacceptably long antibiotic withdrawal times. The effects of the CH4-inhibitors nitroethane (2 mg/m...

  10. Effects of the methane-inhibitors nitrate, nitroethane, lauric acid, Lauricidin**R and the Hawaiian marine algae, Chaetoceros, on ruminal fermentation in vitro

    Science.gov (United States)

    The effects of several methane-inhibitors on rumen fermentation were compared during three 24 h consecutive batch cultures of ruminal microbes in the presence of nonlimiting amounts of hydrogen. After the initial incubation series, methane production was reduced greater than 92% from that of nontre...

  11. Copper addition helps alleviate iron stress in a coastal diatom: Response of Chaetoceros gracilis from the Bay of Bengal to experimental Cu and Fe addition

    Digital Repository Service at National Institute of Oceanography (India)

    Biswas, H.; Bandyopadhyay, D.; Waite, A.

    sedimentation of biomass within the bottles. Based on earlier growth rate measurements, sampling were executed during the maximum growth phase on day 3 of the incubation. All bottles were returned to the clean laboratory for further sampling and analysis. 2....3 Sample Analysis: For total Chl-a determination, 100 mL of the experimental sample from each treatment was filtered onto GF/F filters and kept in -20ºC until analysis. Later, filters were soaked overnight in 5 mL N,N- 6    Dimethyl formamide following...

  12. In vitro comparison of nitroethane, 2-nitro-1-propanol, lauric acid, Lauricidin(R), and the Hawaiian marine algae, Chaetoceros, activity against anaerobically grown Staphylococcus aureus

    Science.gov (United States)

    The gastrointestinal tract of bovines often contains bacteria that contribute to disorders of the rumen and may also contain foodborne or opportunistic human pathogens as well as causative agents of mastitis in cows. Thus, there is a need to develop broad-spectrum therapies that are effective while...

  13. Spatial distribution, seasonality and trap preference of stable fly, Stomoxys calcitrans L. (Diptera: Muscidae), adults on a 12-hectare zoological park

    OpenAIRE

    Ose, Gregory A; Hogsette, Jerome A

    2014-01-01

    Although this study was originally designed to compare the efficacy of two different stable fly traps within 10 sites at a 12-ha zoological park, seasonal and spatial population distribution data were simultaneously collected. The two traps included an Alsynite fiberglass cylindrical trap (AFT) and a blue-black cloth target modified into a cylindrical trap (BCT). Both traps were covered with sticky sleeves to retain the attracted flies. Paired trap types were placed at sites that were 20–100 ...

  14. Effect of mutual interference on the ability of Spalangia cameroni (Hymenoptera: Pteromalidae) to attack and parasitize pupae of Stomoxys calcitrans (Diptera: Muscidae)

    DEFF Research Database (Denmark)

    Skovgård, Henrik; Nachman, Gösta

    2015-01-01

    h. The number of pupae that were attacked and the number successfully parasitized increased with the parasitoid density and reached a maximum of similar to 70 and 50, respectively. Parasitoid-induced mortality (PIM) was about 20 pupae, irrespective of parasitoid density. The per capita rates of...... attack, successful parasitism and parasitoid-induced mortality declined monotonously with parasitoid density. Progeny sex ratio was female biased for all parasitoid densities, but declined significantly with increasing parasitoid density from similar to 70% females at the lowest density to similar to 60......% at the highest. Mutual interference was incorporated into a functional response model to predict the attack rate and the rate of successful parasitism at different temperatures, host densities and parasitoid densities. The model explained 93.5% of the variation in the observed number of attacked...

  15. Gut fluorescence analysis of barnacle larvae: An approach to quantify the ingested food

    Science.gov (United States)

    Gaonkar, Chetan A.; Anil, Arga Chandrashekar

    2012-10-01

    Gut fluorescence analysis can provide a snapshot of ingested food and has been employed in feeding studies of various organisms. In this study we standardised the gut fluorescence method using laboratory-reared barnacle larvae (Balanus amphitrite) fed with mono-algal diet Chaetoceros calcitrans, a unicellular diatom at a cell concentration of 2 × 105 cells ml-1. The gut fluorescence of IV-VI instar nauplii was found to be 370(±12) ng chlorophyll a larva-1 and in faecal pellets it was 224(±63) ng chlorophyll a larva-1. A phaeopigment concentration in larval gut was found to be 311(±13) ng larva-1 and in faecal pellets it was 172(±61) ng larva-1. The study also analysed larval samples collected from the field during different seasons from a tropical environment influenced by monsoons (Dona Paula bay, Goa, west coast of India), with characteristic temporal variations in phytoplankton abundance and diversity. Gut fluorescence of larvae obtained during the post-monsoon season was consistently higher when compared to the pre-monsoon season, suggesting the predominance of autotrophic forms in the larval gut during the post-monsoon season. Whereas, the low gut fluorescence obtained during the pre-monsoon season indicated the ingestion of food sources other than autotrophs. Such differences observed in the feeding behaviour of larvae could be due to differential availability of food for the larvae during different seasons and indicate the capability of larvae to feed on wide range of food sources. This study shows the value of the fluorescence method in feeding studies of planktotrophic organisms and in the evaluation of ecosystem dynamics.

  16. Molecular characterization and immunolocalization of the olfactory co-recepter Orco from two blood-feeding muscid flies, the stable fly (Stomoxys calcitrans, L.) and the horn fly (Haematobia irritans irritans, L.)

    OpenAIRE

    Olafson, Pia Untalan

    2013-01-01

    Biting flies are economically important, blood-feeding pests of medical and veterinary significance. Chemosensory-based biting fly behaviors, such as host/nutrient source localization and ovipositional site selection, are intriguing targets for the development of supplemental control strategies. In an effort to expand our understanding of biting fly chemosensory pathways, transcripts encoding the highly conserved insect odorant co-receptor (Orco) were isolated from two representative biting f...

  17. Population Dynamics of Stable Flies Stomoxys calcitrans (Diptera: Muscidae) at an Organic Dairy Farm in Denmark based on a Mark-recapture with Destructive Sub-Sampling

    DEFF Research Database (Denmark)

    Skovgård, H.; Nachman, G.

    2012-01-01

    of a modified version of Bailey's triple catch method. In both years, the abundance of flies peaked in July. Using a statistical model, we were able to explain 86.6% of the variation in the per capita growth rate r as a function of current temperature, precipitation, and population size. Omitting precipitation...... from the model, it still explained 69.3%. The model predicts that stable flies have a temperature optimum at 21.8°C, and that no development will take place when temperatures inside the stable are below 10.2°C or above 33.5°C. At the optimal temperature the intrinsic rate of natural increase is 0.070 d......-1. The per capita dilution rate increased with temperature and decreased with population size, whereas no effect of these factors on the per capita loss rate could be shown. Mean adult survival time was estimated to 6.3 d with 95% CL ranging from 4.3 to 11.1 d. The study points at the possibility...

  18. Screening of High-quality Feed Microalgae in Cultivation of Juvenile Intertidal Shellfish, Sinonovacula constricta%缢蛏稚贝优质微藻饵料的筛选

    Institute of Scientific and Technical Information of China (English)

    马斌; 周海波; 徐继林; 周成旭; 严小军

    2011-01-01

    为了筛选缢蛏稚贝的合适饵料及其最优组合投饵方式,比较了8种常见饵料微藻单种投喂和混合投喂对缢蛏稚贝生长的影响.结果显示:单种投喂时,角毛藻和金藻饵料效果最佳,云微藻和XSWG仅次于角毛藻和金藻,对于规格较大的缢蛏稚贝扁藻饵料效果较佳,而对于规格较小的缢蛏稚贝其饵料效果并不太好,这5种微藻都可以作为缢蛏稚贝培育过程中的优良饵料选择:微绿球藻、巴夫藻饵料效果较差,不是缢蛏的良好饵料;而A5不仅对缢蛏稚贝没有饵料效果还具有一定的毒害作用.选择优良饵料微藻进行混合投喂,其效果要优于单种投喂;混合投喂时,一些单种投喂饵料效果不佳的微藻品种可以作为优质饵料不足时的补充;对缢蛏稚贝有毒害作用的微藻品种绝对不能作为混合投喂时的饵料选择.%In order to select the appropriate feed and optimum combinational feeding methods of juvenile shellfish, Sinonovacula constricta, the feeding effects of eight common microalgae are compared in this study. The best feeding effects are found in Chaetoceros calcitrans and Isochrysis galbana, followed by YW0980 and XSWG., through feeding with single microalgae. The feeding result of Platymonas helgolandica on juvenile Sinonovacula with larger size is more effective than those with smaller size. All of the five feed microalgae above can be used as good choices during the cultivation of juvenile Sinonovacula. Poor results are identified in Pavlova viridis and Nannochloropsis oculata, which are found to be the inappropriate feed for juvenile Sinonovacula. However, not only little feed effect but also some toxic effect is noted in the microalgae named A5. Relative to those feeding with single microalgae the better effects are achieved in mixed feeding with high-quality microalgae. The experimental results of feeding with the mixed microalgae show that the poor

  19. The Expert Ceiling in Epistemological Beliefs

    Science.gov (United States)

    Barnard, Lucy

    2007-01-01

    Paulsen and Wells (1998) stated that, "it seems unlikely that substantial differences in epistemological beliefs across domains would persist in studies of faculty or other more advanced experts," (p. 380). This statement implies the existence of an upper limit or ceiling effect in the epistemological beliefs among experts. Faculty members are…

  20. EMAP: MYTHS, HOBGOBLINS AND CRUSAES

    Science.gov (United States)

    Paulsen, Steve and Kevin Summers. In press. EMAP: Myths, Hobgoblins and Crusades (Abstract). To be presented at EMAP Symposium 2004: Integrated Monitoring and Assessment for Effective Water Quality Management, 3-7 May 2004, Newport, RI. 1 p. (ERL,GB R980). The Environment...

  1. Making Cooperative Learning Work in the College Classroom: An Application of the "Five Pillars" of Cooperative Learning to Post-Secondary Instruction

    Science.gov (United States)

    Jones, Karrie A.; Jones, Jennifer L.

    2008-01-01

    Cooperative learning is viable yet generally underutilized method of instruction at the college level (Paulsen and Faust, 2008). This paper highlights the work of teacher educator Dr. Paul J. Vermette in his implementation of cooperative learning based practices in a graduate level Multicultural education course. In analyzing the "Five…

  2. Planktonic diatoms of the Zuari estuary, Goa (west coast of India)

    Digital Repository Service at National Institute of Oceanography (India)

    Redekar, P.D.; Wagh, A.B.

    and 30 (13 genera) Centrales. The common diatoms observed were Chaetoceros borealis, C. decipiens, Biddulphia regia, B. sinensis, Coscinodiscus conscinnus, C. subtilis, C. grani, Navicula inflexa, N. oblonga, Amphora turgida, A. ovalis, Nitzschia sigma...

  3. Abundance of bacterial and diatom fouling on various surfaces

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi

    , Coscinodiscus sp, Fragilaria sp, Liemophora sp, Chaetoceros sp and Rhizoselenia sp. Pennate forms were more dominant as compared to the centrales. The mucilaginous fibrillar material entrapping bacteria and diatoms formed a two-tiered layer on study surfaces...

  4. Seasonality and composition of phytoplankton in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sawant, S.S.; Madhupratap, M.

    population when three seasons were combined, followed by cyanobacteria (7%) and dinoflagellate (6%). The common diatoms were Nitzschia sp., N. seriata, N. longissima, Thalassiothrix spp., Rhizosolenia spp. and Chaetoceros spp. Some diatoms like Fragilaria sp...

  5. Vigour Health: the ASC-Series launch in Canada

    OpenAIRE

    Danielsen, David M.; Fredriksen, Joakim; Nordli, Espen; Nøstberg, Bjørn R.

    2008-01-01

    This report is part of the authors’ bachelor degree in International Marketing and analyzes the Canadian vitamins and dietary supplements (VDS) industry. Based on this analysis, the authors will be proposing how Vigour can enter the market. Vigour Health was founded in 2006 by Omar Paulsen Bekheet and John Ivar Andre and the goal was to introduce a new lifestyle concept that should be inventive in its approach. Vigour utilizes raw materials from the northern parts of Norway, an...

  6. Organizational Communication and Media

    OpenAIRE

    Tække, Jesper

    2008-01-01

     The paper reflects an interest in the relation between organizational communication and media. It tries to answer the question, how we can observe the relationship between organizational communication and media. It is a work-in-progress which tries to combine organizational studies inspired of Niklas Luhmann (Tække & Paulsen 2008, Tække 2008a) with analysis of how organizations communicate in and about media. Using systems theory and form theory, it puts forward a theoretical framework a...

  7. Efficacy and Safety of Catnip (Nepeta cataria) as a Novel Filth Fly Repellent

    Science.gov (United States)

    The essential oil of catnip (Nepeta cataria) has recently been reported as an alternative mosquito repellent on mosquitoes both topically and spatially. The present study reports that catnip oil resulted in an average repellency of 96% in feeding against stable fly (Stomoxys calcitrans) and 79% to t...

  8. Development and oviposition preference of house flies and stable flies (Diptera: Muscidae) in six substrates from Florida equine facilities

    Science.gov (United States)

    House flies, Musca domestica L., and stable flies, Stomoxys calcitrans (L.), (Diptera: Muscidae), common pests on equine facilities, were studied in the laboratory to determine their oviposition preferences and larval development on six substrates commonly found on equine facilities. The substrates...

  9. Effect of biogenic amines on the mating and egg-laying behaviors in the stable fly

    Science.gov (United States)

    The stable fly Stomoxys calcitrans (L.) (Diptera: Muscidae), is one of the most significant biting fly pests affecting livestock.The annual economic damage to the U.S. cattle industry is estimated at over one billion US dollars. Biogenic amines are known to play critical roles in feeding and reprodu...

  10. External morphology of stable fly (Diptera: Muscidae) larvae

    Science.gov (United States)

    Scanning electron microscopy was used to examine the external morphology of first-, second-, and third-instar stable flies (Stomoxys calcitrans (L.)). In the cephalic region, the antennae, labial lobe, and maxillary palpi are morphologically similar among instars. Antennae comprise a prominent ante...

  11. Comparison of the Olfactory Preferences of Four Species of Filth Fly Pupal Parasitoid Species (Hymenoptera: Pteromalidae) for Hosts in Equine and Bovine Manure

    Science.gov (United States)

    House flies (Musca domestica L.) and stable flies (Stomoxys calcitrans (L.)) (Diptera: Muscidae) are common pests in equine and cattle facilities. Pupal parasitoids primarily in the genera Spalangia and Muscidifurax (Hymenoptera: Pteromalidae) can be purchased for biological control of these flies. ...

  12. Freeze dried blood and development of an artificial diet for blood feeding arthropods

    International Nuclear Information System (INIS)

    The goals of the research were to determine the biochemical differences between freeze dried bovine and porcine blood relative to their nutritional value to Glossina palpalis palpalis and Stomoxys calcitrans and to develop an artificial diet for mass rearing these flies. Freeze dried bovine and porcine blood were found to differ in their amino acid content; total dietary lipids did not significantly differ, but some notable exceptions were found in fatty acid content. Both sonication and addition of foetal bovine serum to freeze dried bovine blood improved its nutritional value for G. p. palpalis. A two component, semi-defined artificial diet was developed for G. p. palpalis and S. calcitrans. The College Station diet consisted of lipid contaminated bovine haemoglobin (BHb) and bovine serum albumin (BSA). To conduct dietary deletion tests, a process was developed for preparing large quantities of ultrapure lipid free bovine haemoglobin. S. calcitrans fed on lipid free BHb plus BSA had zero fecundity. Lipids were re-added to the protein diet in three forms: (1) lipid contaminated BHb, (2) pure erythrocyte ghosts, and (3) pure lipids. It was found that membrane lipid from the erythrocyte is required by S. calcitrans. A defined artificial diet consisting of lipid free BHb, BSA, sphingomyelin, phosphatidyl ethanolamine, phosphatidyl serine and cholesterol gave normal adult survival, as well as near normal fecundity and percentage egg hatch for S. calcitrans. Knowing the identity of the lipids, it is now possible to prepare dietary formulations to alleviate dependency on the blood proteins BHb and BSA. (author). 34 refs, 1 fig., 15 tabs

  13. Produção e qualidade de uvas de mesa 'Sugraone' sobre diferentes porta-enxertos no Submédio do Vale do São Francisco Production and quality of table grapes 'Sugraone' on different rootstocks in the São Francisco River Valley

    Directory of Open Access Journals (Sweden)

    Patrícia Coelho de Souza Leão

    2011-09-01

    Full Text Available O presente trabalho teve como objetivos avaliar o comportamento agronômico da cultivar de uva de mesa sem sementes Sugraone sobre quatro porta-enxertos nas condições do Submédio do Vale do São Francisco. O experimento foi conduzido em um vinhedo comercial no município de Sento Sé-BA durante quatro ciclos de produção (2002 à 2004, em sistema de condução do tipo latada e irrigação por gotejamento. Os tratamentos consistiram de quatro cultivares de porta-enxerto ('Paulsen 1103', 'SO4', 'Harmony' e '420A', utilizando-se delineamento experimental em blocos ao acaso. Foram obtidas maiores produções por planta e vigor vegetativo sobre o porta-enxerto 'Paulsen 1103'. Também observou-se uma tendência de maior massa de cachos, massa e tamanho de bagas sobre este porta-enxerto, embora tenham ocorrido variações entre os ciclos de produção. O porta-enxerto exerceu influência sobre o teor de sólidos solúveis totais, mas não afetou a acidez total e a relação SST/ATT dos frutos.The present work aimed to evaluate the agronomic performance of the seedless grape cultivar Sugraone on four rootstocks in the São Francisco Valley. The trial was carried out in a commercial vineyard in Sento Sé, State of Bahia for four seasons (2002 to 2004. The treatments were four cultivars of rootstock ('Paulsen 1103', 'SO4', 'Harmony' and '420A', using a randomized block design. The highest yield per plant and vegetative vigor were obtained on the rootstock Paulsen 1103. Also there was a tendency for higher mass of bunches, mass and size of berries on the same rootstock, although there were variations between seasons. The rootstock showed positive influence on the content of soluble solids, but did not affect the total acidity and TSS/TA. Young plants of grapevine cv. Sugraone showed good agronomic performance on Paulsen 1103, but it is important to continue the studies for a larger number of years to recommend their use in the São Francisco Valley.

  14. [Ingestion and digestion of seven species of microalgae by larvae of Strombus gigas (Mesogastropoda: Strombidae)].

    Science.gov (United States)

    Patiño Súarez, V; Aldana Aranda, D

    2000-12-01

    The potential nutritional value of seven microalgal diets as measured by their ingestibility and digestibility to queen conch Strombus gigas larvae was tested with 30 day old larvae reared at 28 degrees C and fed at 1000 cells x ml(-1). The algae were Tetraselmis suecica, Tetraselmis chuii Isochrysis aff. galbana, Dunaliella tertiolecta, Chlamydomonas coccoides, Chaetoceros sp. and Thalassiosira fluviatilis. Ingestion and digestion were measured by the four nutritional stages studied with epifluorescence microscopy with live larvae. Temporal and absolute indices showed that larvae fed Chaetoceros sp. and T. fluviatilis had lower ingestion and digestion levels. The other algae are recommend to feed S. gigas larvae. PMID:15266796

  15. Feeding behaviour of salp Thalia democratica (Thaliacea)

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Achuthankutty, C.T.; Bhattathiri, P.M.A.; Madhupratap, M.

    The salp Thalia democratica was found to feed on Chaetoceros sp. continuously during the entire experimental period of 24 hours. The rate of consumption (0.09-0.16% animal sup(-1) h sup(-1)), however, did not differ significantly. Faecal output also...

  16. Quantitative grain density autoradiography and the intraspecific distribution of primary productivity in phytoplankton

    International Nuclear Information System (INIS)

    Analysis of a method of grain density autoradiography demonstrates that reliable measurements of the primary productivity of individual phytoplankton species can be obtained with this technique. Grain density autoradiography is particularly useful for providing an estimate of the intraspecific distribution of primary productivity. As an example, the productivity distribution of the marine diatom Chaetoceros curvisetus became positively skewed during a period of population decline

  17. Cultivation of shear stress sensitive and tolerant microalgal species in a tubular photobioreactor equipped with a centrifugal pump

    NARCIS (Netherlands)

    Michels, M.H.A.; Goot, van der A.J.; Vermuë, M.H.; Wijffels, R.H.

    2016-01-01

    The tolerance to shear stress of Tetraselmis suecica, Isochrysis galbana, Skeletonema costatum, and Chaetoceros muelleri was determined in shear cylinders. The shear tolerance of the microalgae species strongly depends on the strain. I. galbana, S. costatum, and C. muelleri exposed to shear stress b

  18. Observations on feeding behaviour and survival rates in the estuarine calanoid copepods Acartia spinicauda and Heliodiaptomus cinctus (Crustacea: Copepoda: Calanoida)

    Digital Repository Service at National Institute of Oceanography (India)

    Srivastava, Y.; Fernandes, Brenda; Goswami, S.C.; Goswami, U.; Achuthankutty, C.T.

    to feed on T. gracilis (90.08%) as compared to S. costatum (55.87%). A combined feed of Isochrysis galbana (50%) and Chaetoceros sp. (50%) was found to be most satisfactory in case of H. cinctus as there was no mortality till the 8th day and only 57...

  19. Trocas gasosas de mudas de videira, obtidas por dois porta-enxertos, submetidas à deficiência hídrica Gas exchange of vine cuttings obtained from two graftings submitted to water deficiency

    Directory of Open Access Journals (Sweden)

    Claudia Rita de Souza

    2001-10-01

    Full Text Available Este trabalho teve como objetivo avaliar o efeito da deficiência hídrica e de dois porta-enxertos nas trocas gasosas de mudas de videira cultivadas em vasos, nas condições de casa de vegetação. Utilizou-se como copa a 'Niágara Rosada' (Vitis labrusca, e como porta-enxertos, o 101-14 (V. riparia e o 1103 Paulsen (V. rupestris x V. berlandieri. Doze dias após a suspensão da rega, o potencial hídrico foliar da combinação 'Niágara Rosada'/101-14 apresentou os menores valores (-2,80 MPa em relação à 'Niágara Rosada'/1103 Paulsen (-2,10 MPa nas plantas não-irrigadas, enquanto o teor relativo de água variou apenas entre os tratamentos hídricos. Com a evolução do estresse hídrico, houve uma sensível redução nas trocas gasosas da cultivar 'Niágara Rosada', que apresentaram valores próximos de zero, devido ao fechamento dos estômatos, sem diferenças entre os porta-enxertos. Somente após 12 dias sem rega, os porta-enxertos influenciaram a eficiência no uso da água e eficiência fotoquímica do fotossistema II, onde a 'Niágara Rosada' enxertada sobre o 101-14 apresentou valores inferiores ao 1103 Paulsen. Entretanto, durante o período de suspensão da rega, os porta-enxertos não influenciaram as trocas gasosas da cultivar 'Niágara Rosada', e apresentaram comportamento semelhante em condições de baixa disponibilidade hídrica.The present work aimed to evaluate the water deficiency effect and two graftings on the gas exchange of vine cuttings under greenhouse conditions. 'Niágara Rosada' (Vitis labrusca was used as scion, and 101-14 (V. riparia x V. rupestris and 1103 Paulsen (V. rupestris x V. berlandieri were used as rootstocks. Twelve days after watering suspension, the leaf water potential of the combination 'Niágara Rosada'/101-14 showed lower (-2.80 MPa in relation to 'Niágara Rosada'/1103 Paulsen (-2.10 MPa in the non-irrigated plants, while relative water content altered only among watering levels. With the

  20. Disponibilidade hídrica, radiação solar e fotossíntese em videiras 'Cabernet Sauvignon' sob cultivo protegido Water supply, solar radiation and photosynthesis in 'Cabernet Sauvignon' grapevines under plastic covering

    OpenAIRE

    Clenilso Sehnen Mota; Cassandro Vidal Talamini do Amarante; Henrique Pessoa dos Santos; Jackson Adriano Albuquerque

    2009-01-01

    O objetivo deste trabalho foi avaliar os efeitos da cobertura de videira 'Cabernet Sauvignon' com lona plástica translúcida sobre a disponibilidade de luz e água, a concentração foliar de clorofila e a fotossíntese. As plantas com cinco anos de idade foram conduzidas em sistema 'Y' sobre porta-enxerto Paulsen 1103. O experimento seguiu o delineamento em blocos ao acaso, com dois tratamentos (plantas sem e com cobertura plástica) e quatro repetições de 15 plantas (unidade experimental). A cobe...

  1. On non-trivial barrier solutions of the dividend problem for a diffusion under constant and proportional transaction costs

    CERN Document Server

    Bai, Lihua

    2012-01-01

    In Bai and Paulsen (SIAM J. Control optim. 48, 2010) the optimal dividend problem under transaction costs was analyzed for a rather general class of diffusion processes. It was divided into several subclasses, and for the majority of subclasses the optimal policy is a simple barrier policy; whenever the process hits an upper barrier $\\bar{u}^*$, reduce it to $\\bar{u}^*-\\xi$ through a dividend payment. After transaction costs, the shareholder receives $k\\xi-K$. It was proved that a simple barrier strategy is not always optimal, and here these more difficult cases are solved. The optimal solutions are rather complicated, but interesting.

  2. Raleio de cachos em vinhedos de altitude e qualidade do vinho da cultivar Syrah Cluster thinning in high altitude vineyards and wine quality from the cultivar Syrah

    OpenAIRE

    Leonardo Cury da Silva; Leo Rufato; Aike Anneliese Kretzschmar; José Luiz Marcon Filho

    2009-01-01

    O objetivo deste trabalho foi avaliar o efeito de diferentes intensidades de raleio de cachos de uvas (Vitis vinifera L.), em vinhedos de altitude, sobre a evolução dos compostos fenólicos durante a maturação da uva. O experimento foi conduzido em São Joaquim, SC, a uma altitude média de 1.230 m, em videiras da cv.Syrah, enxertadas sobre 'Paulsen 1103', conduzidas em espaldeira, em duplo cordão esporonado, espaçadas em 3x1,2 m, com cobertura antigranizo. Os tratamentos de raleio foram definid...

  3. Bildung in the Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael Eric

    We are living in a period where new social structures arise in the communicative space and wake of digital media. This means that we must try to adapt to a changing social world within all social arenas like economy, work-life, love relations and last but not least education. The question...... in education today and tomorrow. The paper draws on empirical findings from the Socio Media Education experiment, a Danish action research project in an upper secondary school from 2011-214 (Tække & Paulsen 2013a, 2015a, 2016a, 2016b)....

  4. 80 aastat tagasi : Jaanuar 1928 / Mati Märtin

    Index Scriptorium Estoniae

    Märtin, Mati

    2008-01-01

    Muusikasündmustest 80 aastat tagasi: Noorte Meeste Kristliku Ühing andis loengkontserte, Tallinna Kaarli kirikus tuli ettekandele A.Dvoraki "Stabat Mater" (juhatas Johannes Paulsen, esinesid Jekeli lauluselts, Estonia sümfooniaorkester ja solistid Olga Torokoff-Tiedeberg, J. Badendiesk-Inger, Arnold Vissmann ja Karl Viitol), trükist ilmus Johannes Jürgensoni (Juhan Jürme) "12 vaimulikku laulu" (kirjastajaks Tallinna Kaarli Lauluselts), 50. surma-aastapäeva puhul meenutati kirikumuusikut Johann August Hagenit, meenutati Keila muusikameest Jakob Maabergi

  5. Avaliação de substratos para inoculação micorrízica e aclimatização de dois porta-enxertos de videira micropropagados Evaluation of substrates for mycorrhization and weaning of two micropropagated grapevine rootstocks

    Directory of Open Access Journals (Sweden)

    Josy Moraes Zemke

    2003-11-01

    Full Text Available O objetivo deste trabalho foi selecionar substratos favoráveis à associação micorrízica na produção de mudas micropropagadas de porta-enxertos de videira. Os porta-enxertos SO4 e Paulsen 1103 foram aclimatizados por três semanas em bandejas alveoladas, contendo seis substratos (à base de solo, composto termofílico, casca de arroz carbonizada, vermiculita, areia e um substrato comercial, com e sem inoculação micorrízica. No final da aclimatização e dez semanas depois, avaliaram-se a colonização micorrízica, a matéria seca de parte aérea e o comprimento radicular das plantas. A intensidade de colonização micorrízica variou em razão dos porta-enxertos e dos substratos utilizados na aclimatização, havendo interação significativa entre os dois fatores. O substrato comercial proporcionou a maior produção de biomassa, mas promoveu a menor colonização micorrízica em todos os porta-enxertos. As combinações mais favoráveis de produção de biomassa vegetal e de taxa de colonização micorrízica ocorreram no porta-enxerto Paulsen 1103, no substrato à base de solo, composto termofílico e areia e, no porta-enxerto SO4, no substrato à base de solo, composto termofílico e vermiculita.The aim of this work was to select substrates conductive to the establishment of arbuscular mycorrhizas in the production of micropropagated grapevine rootstocks. Micropropagated SO4 and Paulsen 1103 rootstock plantlets were weaned for three weeks in trays with mycorrhizal fungal- inoculated or uninoculated substrates (prepared with soil, compost, calcined rice hulls, vermiculite and sand, besides a commercial substrate. At the end of the weaning period and ten weeks after, shoot and root growth and mycorrhizal root colonization were evaluated. Mycorrhizal root colonization varied according to the rootstock and substrates, with a significant interaction between these factors. The commercial substrate was associated with the highest increase

  6. Determination of callusing performance and vine sapling characteristics on different rootstocks of ‘Merzifon Karası’ grape variety (Vitis vinifera L.)

    OpenAIRE

    Bülent KÖSE; ÇELIK, Hüseyin; Karabulut, Besim

    2015-01-01

    Grafted vines are the only option while establishing vineyards over the sites contaminated with phylloxera. Furthermore, grafted vines used to establish new vineyards should be well-developed, healthy and compatible with the scions. In this research, we aimed to find out the most suitable rootstock for ‘Merzifon Karası’ using ten rootstocks (140 Ruggeri, 110 R, 99 R, 41B, 5C, 5BB, SO4, 1103 Paulsen 140 Ruggeri and Rupestris du Lot) in 2010 and 2011. The effects on the callusing performance, g...

  7. Thermal requirement and phenology of different cultivars of Vitis labrusca on different rootstocks

    Directory of Open Access Journals (Sweden)

    Luciane Bertoletti Barros

    2015-08-01

    Full Text Available The knowledge of phenological stages and thermal requirement are important in vineyard management because provides information for production and quality of the grapes. This study had the objective to evaluate phenology and thermal demand of the grape cultivars Bordô, Concord, and BRS Carmem on rootstocks Paulsen 1103, IAC 766, and VR 043-43. The experiment was conducted in a family owned vineyard in Campo Largo, Paraná State, Brazil. The vineyard was carried out on ridges with semi-trellis in ‘T’ systems conducting (Geneva Double Curtain trellis. The evaluations were assessed during the production cycles of 2011/2012 and 2012/2013. The phenology was evaluated with a scale of 13 phenological stages. The thermal demand was defined by calculating the degree-days accumulation (DD from bud swelling until harvest stage. The cultivar BRS Carmem had the longest cycle, being influenced by the rootstock, IAC 766 e Paulsen 1103 showed opposite results for cycle time. The cultivar Concord was more stable; there was no influence of rootstock on the cycle or of the thermal demand on the two harvests. The duration of the phenological cycle in 2012/2013 was lower than on the first harvest. Thermal requirement of ‘BRS Carmem’ was influenced by tree different rootstocks, ‘Concord’ was not influenced, and the results to ‘Bordô’ were not consistent.

  8. Insights into aerosol formation chemistry from comprehensive gas-phase precursor measurement in the TRAPOZ chamber experiments; an overview

    Science.gov (United States)

    Carr, Timo; Wyche, Kevin; Monks, Paul S.; Camredon, Marie; Alam, Mohammed S.; Bloss, William J.; Rickard, Andrew R.

    2010-05-01

    Aerosols have a profound affect on the environment on local, regional and even global levels, with impacts including adverse health effects, (Alfarra, Paulsen et al. 2006) visibility reduction, cloud formation, direct radiative forcing (Charlson, Schwartz et al. 1992) and an important role in influencing the climate due to their contribution to important atmospheric processes (Baltensperger, Kalberer et al. 2005; Alfarra, Paulsen et al. 2006). The Total Radical Production from the OZonolysis of alkenes (TRAPOZ) project was used to study the gas phase and radical chemistry along with secondary organic aerosol (SOA) formation for a number of different alkenes and terpenes. In order to better the scientific knowledge regarding the oxidation mechanisms of terpene and alkene species along with radical and SOA formation, the experiments were conducted under varying conditions controlled and monitored by the EUropean PHOto REactor (EUPHORE) simulation chamber in Valencia, Spain. A vast number of instruments enabled a detailed examination of the chemistry within oxidation of each precursor. However the work here will focus on the results obtained from the University of Leicester Chemical Ionisation Reaction Time-of-Flight Mass Spectrometer (CIR-TOF-MS). With regard to the gas phase chemistry an analysis of the degradation of the precursor Volatile Organic Compounds (VOCs) and evolution of certain gas phase species in each experiment has been presented and discussed.

  9. Dimethylsulfoniopropionate (DMSP) cell quota of key Southern North Sea spring diatoms and Phaeocystis globosa.

    Science.gov (United States)

    Speeckaert, Gaëlle; Gypens, Nathalie; Lancelot, Christiane; Borges, Alberto V.

    2015-04-01

    Dimethylsulfide (DMS) in the ocean results of complex transformations of dimethylsulfoniopropionate (DMSP) produced by phytoplankton under different controls, including microbial transformation pathways. The phytoplankton composition is an important factor of variability due to the species dependence of the DMSP production and conversion to DMS. To better appraise the link between phytoplankton diversity and the DMS(P) cycling in the Southern North Sea we present measurements of the DMSP cell quota of key spring phytoplankton species (Skeletonema costatum, Thalassiosira rotula, Rhizosolenia delicatula, Asterionella glacialis, Nitzschia closterium, Chaetoceros debilis, Chaetoceros socialis and Phaeocystis globosa) isolated from the North Sea and maintained in non-limiting and axenic laboratory culture conditions. Results are discussed with regards to literature data and hypothesis currently used in DMS(P) biogeochemical models.

  10. Continuous harvesting of microalgae by new microfluidic technology for particle separation.

    Science.gov (United States)

    Hønsvall, Birgitte K; Altin, Dag; Robertson, Lucy J

    2016-01-01

    A new microfluidic chip based on a trilobite structure, designed for continuously concentrating particles in moving fluids, was investigated as a pre-concentration method for microalgal harvesting. The chip has a 5-μm gap limit and was tested for concentrating the microalgae Rhodomonas baltica, Chaetoceros sp. and Thalassiosira weissflogii. The chip was able to concentrate rigid cells and to sort them according to size. However, optimization with respect to cell properties, such as size and flexibility, needs further work. Although no clogging of the chip was seen for R. baltica and Chaetoceros sp., production of exopolymers by T. weissflogii made harvesting challenging for this species. The Trilobite™ microfluidic chip appears to be a promising tool for pre-concentrating microalgae that are difficult to harvest due to their repelling properties or small size. PMID:26512859

  11. Toxic effects of oil and dispersant on marine microalgae.

    Science.gov (United States)

    Garr, Amber L; Laramore, Susan; Krebs, William

    2014-12-01

    To better understand the potential impacts of the deepwater horizon oil spill on lower trophic level food sources, a series of toxicological laboratory experiments were conducted with two microalgae species. The acute toxicity of oil (tar mat and MC252 crude oil), dispersant (Corexit 9500A), and dispersed oil on growth inhibition (IC50) and motility of Isochrysis galbana and Chaetoceros sp. were determined. There was no impact on cell division (growth) for microalgae exposed to both oil types and mean motility of I. galbana never dropped below 79 %. However, the addition of dispersant inhibited cell division and motility within 24 h, with Chaetoceros sp. being more susceptible to sublethal effects than I. galbana. These results highlight microalgae sensitivity to the use of dispersants in bioremediation processes, which may be a concern for long-term impacts on fisheries recruitment. PMID:25283369

  12. Diatom associations in shelf waters off Paraná State, Southern Brazil: annual variation in relation to environmental factors

    OpenAIRE

    Luciano Felício Fernandes; Frederico Pereira Brandini

    2004-01-01

    The seasonal variation of diatoms in the inshore waters off Paraná State, Southern Brazil was investigated to analyse their temporal dynamics and to detect the main environmental constraints of the planktonic community. Biomass peaks occurred from May to August and from December to March. Among the microplanktonic diatoms, Cerataulina pelagica, Chaetoceros spp., Dactyliosolen fragilissimus, Guinardia striata, Lauderia annulata, Leptocylindrus spp., Pseudo-nitzschia cf. delicatissima, P. austr...

  13. Seasonal changes in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas: General trends based on field survey data 1959-2009

    Science.gov (United States)

    Yang, Shu; Han, Xiurong; Zhang, Chuansong; Sun, Baiye; Wang, Xiulin; Shi, Xiaoyong

    2014-12-01

    The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll- a concentration in surface seawater was between 0.4 and 8.5 μg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level (including the nutrient supply from the terrestrial runoffs) was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that diatoms were the main phytoplankton in this area, and Skeletonema costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends: 1) Skeletonema (mainly S. costatum) was dominant throughout the year; and 2) seasonal succession trends were Coscinodiscus (spring) → Chaetoceros (summer and autumn) → Coscinodiscus (winter). The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas: average annual phytoplankton biomass and dinoflagellate

  14. The effects of eight single microalgal diets on sex-ratio and gonad development throughout European flat oyster (Ostrea edulis L.) conditioning

    OpenAIRE

    Gonzales, Ricardo; Quillien, Virgile; Robert, Rene

    2013-01-01

    To determine the effects of food quality on Ostrea edulis reproduction, European flat oysters were conditioned during two sets of experiments, carried out in spring and autumn, during 40 days at 19 degrees C, in 50 l transparent flow-through tanks, in triplicate, and fed constantly at 900 mu m(3) mu l(-1), with eight different types of microalgae. Four species were fed per group of trials: Isochrysis affinis galbana, Chaetoceros gracilis, Skeletonema marinoi, and Tetraselmis suecica were fed ...

  15. Study On The Phytoplankton And Seasonal Variation Of Lake Simenit (Terme - Samsun, Turkey)

    OpenAIRE

    , Elif Ersanlı; Gönülol, Arif

    2003-01-01

    The composition and seasonal variations of phytoplankton in Lake Simenit were studied between june 2000 to may 2001. 175 taxa belonging to the Cyanoprokaryota, Bacillariophyta, Chlorophyta, Cryptophyta, Dinophyta, Euglenophyta and Xanthophyta divisions were identified. In the phytoplankton species belonging to the genera of Chaetoceros, Cyclotella, Cocconeis, Scenedesmus, Anabaena, Euglena, Trachelomonas caused water blooms in certain months. The Lake water was light alkaline and it was vari...

  16. Effect of Rhodomonas salina addition to a standard hatchery diet during the early ontogeny of the scallop Pecten maximus

    OpenAIRE

    Tremblay, Rejean; Cartier, Simon; Miner, Philippe; Pernet, Fabrice; Quere, Claudie; Moal, Jeanne; Muzellec, Marie-louise; Mazuret, Michel; Samain, Jean-francois

    2007-01-01

    The main objective of this study was to identify algal diets that maximize the survival and growth and alter the biochemical content of Pecten maximus larvae with the aim of improving metamorphosis. We also evaluated the potential of the cryptophyceae Rhodomonas salina as a food source for these larvae. Two flagellates, Isochrysis aff. galbana (T) and Pavlova lutheri (P), and two diatoms, Chaetoceros gracilis (C) or Skeletonema costatum (S), were tested as two ternary diets, namely PTC and PT...

  17. Influence of one selected Tisochrysis lutea strain rich in lipids on Crassostrea gigas larval development and biochemical composition

    OpenAIRE

    Da Costa, F.; Petton, Bruno; Mingant, Christian; Bougaran, Gael; Rouxel, Catherine; Quere, Claudie; Wikfors, Gary H.; Soudant, Philippe; Robert, Rene

    2016-01-01

    Effects of a remarkably high overall lipid Tisochrysis lutea strain (T+) upon gross biochemical composition, fatty acid (FA), sterol and lipid class composition of Crassostrea gigas larvae were evaluated and compared with a normal strain of Tisochrysis lutea (T) and the diatom Chaetoceros neogracile (Cg). In a first experiment, the influence of different single diets (T, T+ and Cg) and a bispecific diet (TCg) was studied, whereas, effects of monospecific diets (T and T+) and bispecific diets ...

  18. Not all calcite ballast is created equal: Differing effects of foraminiferan tests and coccoliths on the aggregation and sinking of diatoms

    Science.gov (United States)

    De La Rocha, C. L.; Schmidt, K.; Gallinari, M.; Cortese, G.

    2011-12-01

    There is a strong correlation between sinking fluxes of CaCO3 biominerals and particulate organic carbon (POC), leading to suggestions that sinking fluxes of CaCO3 might control the amount of POC reaching the deep sea. Research has shown that CaCO3 (which is considerably denser than both seawater and particulate organic matter), in the form of coccoliths produced by coccolithophores, can be incorporated into phytoplankton aggregates, reducing their size and POC content but significantly increasing their sinking velocity (W, in m d-1). Coccoliths are, however, not the only form of CaCO3 common in the water column. The tests of foraminiferans represent roughly half of the global flux of CaCO3 to the seafloor and it is unclear what role they play in "carrying" POC to depth. Tests of foraminiferans are commonly large and heavily calcified enough to sink with velocities of 1 km per day. Foraminiferan tests should not accumulate organic matter, as the resulting aggregate should fall apart when subject to the hydrodynamic shear associated with such rapid sinking. To investigate this, thick cultures of the marine diatom Chaetoceros gracilis were placed into 4.5 L cylindrical tanks. Added to the tanks was either no CaCO3, 4.5 mg L-1 of coccoliths, or 4.5 mg L-1 of foraminiferan tests > 250 μm. The tanks were then placed on roller tables to simulate sinking through the water column. Incubation was done in the dark at 16°C for 2 days. Aggregates formed in all treatments. Aggregates in the Chaetoceros-only tanks were the largest and contained the most POC per aggregate. Aggregates in the coccolith tanks were smaller but had higher sinking velocities for their equivalent spherical diameter (ESD, in mm) (W = 678(ESD) + 173; r2 = 0.52) Foraminiferan tests in the foraminiferan tanks absorbed visible but minor amounts of organic matter and sank extremely rapidly (400-700 m d-1). However, most of the POC in the foraminiferan tanks occurred in aggregates that did not contain

  19. Cell transformation mediated by the Epstein-Barr virus G protein-coupled receptor BILF1 is dependent on constitutive signaling

    DEFF Research Database (Denmark)

    Lyngaa, Rikke Birgitte; Nørregaard, K.; Kristensen, Martin; Kubale, V.; Rosenkilde, M.M.; Kledal, Thomas N

    2010-01-01

    Epstein-Barr virus (EBV) open reading frame BILF1 encodes a seven trans-membrane (TM) G protein-coupled receptor that signals with high constitutive activity through G alpha(i) (Beisser et al., 2005; Paulsen et al., 2005). In this paper, the transforming potential of BILF1 is investigated in vitro...... an intermediately active triple-mutated receptor possessed an intermediate transforming potential. Furthermore, BILF1 expression induced vascular endothelial growth factor secretion in a constitutively active manner. In nude mice, BILF1 promoted tumor formation in 90% of cases, ORF74 (from Kaposi......'s sarcoma-associated herpes virus) in 100% of cases, whereas the signaling-deficient receptor resulted in tumor establishment in 40% of cases. These data suggest that BILF1, when expressed during EBV infection, could indeed be involved in the pathogenesis of EBV-associated diseases and malignancies...

  20. From Analog to Digital Medias in Early Childhood Education

    DEFF Research Database (Denmark)

    Brandt, Erika Zimmer

    2015-01-01

    in a mixed-methods design based on field observation and interviews (Frederiksen, Gundelach and Skovgaard Nielsen 2014) Paradigm, methodology and methods Special sensitivity is directed towards how the dialog between children and educators develops, when they use tablets in educational practice. Ethical......Research aims: The aim of the study is to explore how the encounters between children and their educators alter when the media changes from analog to digital. Relationship to previous research works Tablets and other handheld, electronic devices has become part of everyday life in kindergartens....... Research shows that there are both potential pedagogical difficulties and possibilities connected to using digital media (ex. Thestrup 2015, Tække and Paulsen 2014) Theoretical and conceptual framework: The study is a single case study of an educational experiment (Flyvbjerg 2006). It is carried out...

  1. Synchronous correlation matrices and Connes' embedding conjecture

    Science.gov (United States)

    Dykema, Kenneth J.; Paulsen, Vern

    2016-01-01

    In the work of Paulsen et al. [J. Funct. Anal. (in press); preprint arXiv:1407.6918">arXiv:1407.6918], the concept of synchronous quantum correlation matrices was introduced and these were shown to correspond to traces on certain C*-algebras. In particular, synchronous correlation matrices arose in their study of various versions of quantum chromatic numbers of graphs and other quantum versions of graph theoretic parameters. In this paper, we develop these ideas further, focusing on the relations between synchronous correlation matrices and microstates. We prove that Connes' embedding conjecture is equivalent to the equality of two families of synchronous quantum correlation matrices. We prove that if Connes' embedding conjecture has a positive answer, then the tracial rank and projective rank are equal for every graph. We then apply these results to more general non-local games.

  2. Videira 'Syrah' sobre diferentes porta-enxertos em ciclo de inverno no sul de Minas Gerais

    OpenAIRE

    Frederico Alcântara Novelli Dias; Renata Vieira da Mota; Ana Carolina Fávero; Eduardo Purgatto; Tânia Misuzu Shiga; Claudia Rita de Souza; Rodrigo Meirelles de Azevedo Pimentel; Murillo de Albuquerque Regina

    2012-01-01

    O objetivo deste trabalho foi avaliar a influência de porta-enxertos sobre as características agronômicas, ecofisiológicas e qualitativas da videira 'Syrah' manejada por meio da técnica da dupla poda. As videiras foram enxertadas nos porta-enxertos 'SO4', '110 Richter' e '1103 Paulsen', e sustentadas em sistema espaldeira sem irrigação. Foram avaliadas as características ecofisiológicas, de produção e de composição físico-química das bagas maduras em três safras (2007, 2008 e 2010). Os porta-...

  3. How to Steer and Lead Educational Processes in a Digital Medium Environment?

    DEFF Research Database (Denmark)

    Tække, Jesper

    This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work any more since...... Education (SME), which has worked with possibilities and problems in regard to the digital medium revolution’s disruption of the Danish upper secondary school (Tække & Paulsen 2015a, b, 2014, 2013a, b, c, 2012)....... it was developed in the image of the industrial society and based on a closed classroom. Now with the digital media and wireless networks the classroom is opened and the old way of organizing teaching has become inadequate: The students are disturbed by the new media, instead of learning through them. Inspired...

  4. Synchronous correlation matrices and Connes’ embedding conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Dykema, Kenneth J., E-mail: kdykema@math.tamu.edu [Department of Mathematics, Texas A& M University, College Station, Texas 77843-3368 (United States); Paulsen, Vern, E-mail: vern@math.uh.edu [Department of Mathematics, University of Houston, Houston, Texas 77204 (United States)

    2016-01-15

    In the work of Paulsen et al. [J. Funct. Anal. (in press); preprint arXiv:1407.6918], the concept of synchronous quantum correlation matrices was introduced and these were shown to correspond to traces on certain C*-algebras. In particular, synchronous correlation matrices arose in their study of various versions of quantum chromatic numbers of graphs and other quantum versions of graph theoretic parameters. In this paper, we develop these ideas further, focusing on the relations between synchronous correlation matrices and microstates. We prove that Connes’ embedding conjecture is equivalent to the equality of two families of synchronous quantum correlation matrices. We prove that if Connes’ embedding conjecture has a positive answer, then the tracial rank and projective rank are equal for every graph. We then apply these results to more general non-local games.

  5. Organizational Communication and Media

    DEFF Research Database (Denmark)

    Tække, Jesper

      The paper reflects an interest in the relation between organizational communication and media. It tries to answer the question, how we can observe the relationship between organizational communication and media. It is a work-in-progress which tries to combine organizational studies inspired...... of Niklas Luhmann (Tække & Paulsen 2008, Tække 2008a) with analysis of how organizations communicate in and about media. Using systems theory and form theory, it puts forward a theoretical framework and a strategy for analysing organisational communication in and about media. The medium aspect is inspired...... is a possible framework to draw the two disciplines together in, because it is a theory about the relation between the social and the media it is based on. First the paper sum up the Luhmann inspired theory about organizations, fleshing out how organizations are thought to communicate in and about media and how...

  6. First survey of seasonal abundance and daily activity of Stomoxys spp. (Diptera: Muscidae) in Kamphaengsaen Campus, Nakornpathom province, Thailand.

    Science.gov (United States)

    Masmeatathip, R; Gilles, J; Ketavan, C; Duvallet, G

    2006-09-01

    The seasonal changes and the daily activity of Stomoxyine species (Diptera: Muscidae) were examined, using Vavoua traps, in a dairy and a beef cattle farm in Nakhonpathom province, Thailand during July 2004 to June 2005. Over this period, Stomoxys calcitrans was the most commonly trapped species, followed by S. sitiens and S. indica. For the later species, this is the first report of its presence in Thailand. A total of 80 % of flies were captured during the rainy season from May to October and 20 % during the dry season from November to April. No major difference of fly density was observed between the dairy and the beef cattle farm. The activity pattern of S. calcitrans was diurnal with a peak between 08:00 am to 10:00 am and another less marked one in the afternoon. The activity pattern of S. sitiens and S. indica was mainly crepuscular with 2 peaks, early in the morning (06:00 a.m.) and late in the afternoon (6:00 p.m.). Those species are important pests of livestock in Thailand, where they are known as a mechanical vector of trypanosomes. A better knowledge of their ecology is a prerequisite for more efficient control measures. PMID:17007217

  7. Efecto de diferentes dietas de microalgas sobre la supervivenci y crecimiento de Apocyclops aff. panamensis (Marsh, 1913 (Copépodo: Cyclopoida cultivado bajo condiciones controladas de laboratorio - Effect of different diets from microalga on supervivenci and growth of Apocyclops aff. panamensis (Marsh, 1913 (Copépodo: Cyclopoida cultivated under controlled conditions of laboratory

    Directory of Open Access Journals (Sweden)

    Elifonso Isiordia Perez,

    2006-07-01

    Full Text Available El presente trabajo fue realizado Julio 2001 con el propósito de evaluar el efecto de diferentes dietas de microalgas sobre la supervivencia y crecimiento (desarrollo de Apocyclops aff. Panamensis. El experimento duró 15 días y se realizó en las instalaciones del Instituto de Ciencias del Mar y Limnología (UNAM Unidad académica Mazatlán Sinaloa. El sistema consistió en un acuario de fibra de vidrio (50x30x40 al cual se agregó 4 litros de agua dulce filtrada 5µ se colocó un termostato para presentar condiciones controladas de temperatura (28ºC, así mismo se mantuvo constante el fotoperiodo (8 horas luz. En el interior del acuario se colocó 1 gradilla con 35 tubos de ensayo con 6 ml de agua salada a 32 ‰ filtrada con luz ultravioleta. Los copépodos fueron colectados en la boca del estero el Yugo Mazatlán, Sinaloa, transportados y aclimatados durante 15 minutos. La siembra consistió en colocar 20 nauplios en estadio II en cada tubo de ensayo. Los tratamientos que se aplicaron como alimento fueron: Chaetoceros sp. + Nannocloropsis sp. (50%:50% (T1, Isochrysis sp. + Nannocloropsis sp. (50%:50% (T2, Chaetoceros sp. + Isochrysis sp. (50%:50% (T3, Chaetoceros sp. (100% (T4, Isochrysis sp. (100% (T5, Nannocloropsis sp. (100% (T6, Chaetoceros sp. + Isochrysis sp. + Nannocloropsis sp. (1:1:1 (T7 cada uno con 5 repeticiones. La densidad de microalgas a suministrar para el presente experimento fue de 50,000 células / mililitro. Al finalizar el estudio solo los copépodos que lograron una supervivencia del 15% hasta copepodito 5 fueron los alimentados con Nanocloropsis sp. (100% y la mayor longitud (0.83 mm se presentó en copépodos alimentados con Chaetoceros sp. (100%, De acuerdo a los resultados se concluye que para lograr mayor crecimiento y supervivencia en el cultivo de copépodos Apocyclops aff. Panamensis se recomienda usar estos tratamientos como alimento. The present work was made July 2001 in order to evaluate the effect of

  8. Intensive aggregate formation with low vertical flux during an upwelling-induced diatom bloom

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Tiselius, P.; Mitchell-Innes, B.;

    1998-01-01

    The surfaces of most pelagic diatoms are sticky at times and may therefore form rapidly settling aggregates by physical coagulation. Stickiness and aggregate formation may be particularly adaptive in upwelling systems by allowing the retention of diatom populations in the vicinity of the upwelling...... center. We therefore hypothesized that upwelling diatom blooms are terminated by aggregate formation and rapid sedimentation. We monitored the development of a maturing diatom (mainly Chaetoceros spp.) bloom in the Benguela upwelling current during 7 d in February. Chlorophyll concentrations remained...

  9. Effects of BDE-47 on the antioxidase activities of four species of marine microalgae%BDE-47对4种海洋微藻抗氧化酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    孟范平; 李卓娜; 赵顺顺; 刘娇

    2009-01-01

    运用实验生态学和生物化学的方法,研究了不同质量浓度的2,2',4,4'-四溴联苯醚(BDE-47)对海水小球藻Chlorellaautotropica,牟氏角毛藻Chaetoceros muelleri,中肋骨条藻Skeletonema costatum和赤潮异弯藻Heterosigam akashiwo的抗氧化酶活性的影响.结果表明:在实验设定质量浓度范围内(0.1~2.5 μg·L~(-1)),4种微藻的超氧化物歧化酶(SOD)和过氧化氢酶(CAT)均能出现一定的应激活性,以减少BDE-47胁迫对藻细胞自身的危害,但是酶活增加的幅度却有很大不同.与赤潮异弯藻和中肋骨条藻相比,海水小球藻和牟氏角毛藻的SOD和CAT对BDE-47具有较高的敏感性.4种海洋微藻的SOD和CAT对BDE-47的敏感性顺序依次为:海水小球藻>牟氏角毛藻>中肋骨条藻>赤潮异弯藻.因此,海水小球藻的SOD和CAT可以作为指示海洋环境中BDE-47污染水平的生物标志物.%The toxic effects of 2,2',4,4'-tetrabrominated biphenyl ether (BDE-47) at various concentrations on the activities of anti-oxidases in four species of marine microalgae (Chlorella autotropica, Chaetoceros muelleri, Heterosigam akashiwo and Skeletonema costatum) were examined through experimental ecology and biochemica1 methods. The results indicated that both SOD and CAT activities in the four species were enhanced in various degree to alleviate the oxidative damage from BDE-47 in the concentration range of 0.1~2.5μg·L~(-1). Compared with Heterosigam akashiwo and Skeletonema costatum, Chlorella autotropica and Chaetoceros muelleri were more sensitive to BDE-47 concerning SOD and CAT activities. The sensitivity of the four marine microalgae species to BDE-47 was in the order of Chlorella autotropica > Chaetoceros muelleri > Skeletonema costatum > Heterosigam akashiwo. Therefore, SOD and CAT in Chlorella autotropica could be used as the biomarkers to indicate pollution level of BDE-47 in marine environment.

  10. Efficiency of copper and cupronickel substratum to resist development of diatom biofilms

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S; Anil, A.C.

    for initial days i.e. up to 2 days (Fig. 3a and b). Cluster analyses of the species for all days revealed thatin the case of Cu (6 species - day 1 and 2, 11 species - day 3 and 4) and Cu-Ni (7, 9, 5 and 8 species for days 1, 2, 3 and 4 respectively) species.... pu + + + 4 B. rhombus (Ehrenberg) Smith, W. Bd. rh + + + + + 5 Cerataulina pelagica (Cleve) Hendy Ce. pe + 6 Chaetoceros curvisetus Cleve Ch. cu + + + + + + 7 C. diversus Ehrenberg Ch. dv + 8 C. lorenzianus Grunow Ch. lr + 9 Climacodium...

  11. The community structure and the seasonal changes of phytoplankton in Dayao Bay in Dalian Coast from 2006 to 2007%2006-2007年大连大窑湾海区浮游植物的群落结构及其季节变化

    Institute of Scientific and Technical Information of China (English)

    赵文; 魏洪祥; 郭凯

    2011-01-01

    于2006年10月至2007年10月,逐月采样研究了大窑湾海区浮游植物的种类组成、密度以及物种多样性.调查结果表明:共发现浮游植物5门42属75种,其中硅藻31属59种,甲藻8属13种,金藻1属1种,蓝藻1属1种,黄藻门1属1种;大窑湾海区浮游植物的生态类型几乎都为温带近岸性物种,个别为暖海性物种或大洋性物种;硅藻在种数和密度上均占优势,主要优势种为旋链角毛藻Chaetoceros curvisetus、中心圆筛藻Coscinodiscus centralis、星脐圆筛藻Coscinodiscus asteromphalus、浮动弯角藻Eucampia zoodicacus、波氏直链藻Melosira borreri、具毒冈比甲藻Gambierdiscus toxicus、刚毛根管藻Rhizosolenia setigera、尖刺拟菱形藻Nitzschia pungens、柔弱角毛藻Chaetoceros debilis;浮游植物密度在2007年的3月和7月出现春、秋两个高峰期,多样性指数为0.36-3.17,平均值为1.65,表明该海区属于中度污染.%The abundance, species composition and biodiversity of phytoplankton were studied in Dayao Bay in Dalian coast from October 2006 to October 2007. A total of 75 species (excluding unidentified ones) , 42 genera and 5 phyla were found in the survey area, including59 species, and 31 genera belonging to Bacillariophyta,8 genera and 13 species belonging to Dinophyta, 1 species and 1 genera belong to Chrysophyta, 1 species belonging to Cyanophyta, and 1 species belonging to Xanthophyta. The dominant species were found in bacillariophyta including Chaetoceros curvisetus, Coscinodiscus centralis, Coscinodiscus asteromphalus, Eucampia zoodkacus, Melosira borreri, Gambierdiscus toxicus, Rhizosolenia, Nitzschia pungens, and Chaetoceros debilis. The cell abundance peaks were observed in March and July of 2007, and the species diversity index was changed from 0.36 to 3.17 with an average of 1.65, indicating that the water quality in this area is meso-pollution.

  12. Humus de lombriz Eisenia foetida para cultivar dos microalgas marinas como alimento de larvas de camarón

    OpenAIRE

    Guerra Aznay, M.

    2011-01-01

    Para evaluar el extracto líquido de humus de lombriz roja californiana Eisenia foetida como un nuevo medio alternativo de cultivo de las microalgas Tetraselmis tetrathele y Chaetoceros muelleri, se probaron cuatro diluciones (EH50, EH200, EH350 y EH500 mL) empleando como control al medio f/2 Guillard (MG). Las concentraciones celulares de T. tetrathele no mostraron diferencias (p>0.05) entre el tratamiento MG y el tratamiento EH200 mL. Los valores medios ± DS fueron de...

  13. Alternativa de biofertilizante como medio de cultivo para el crecimiento poblacional de dos microalgas marinas empleadas en la camaronicultura

    OpenAIRE

    Guerra Aznay, M.; Pérez Jar, L.; Leal Lorenzo, S.; Jaime Ceballos, B.; Jiménez Cabrera, R.; Pérez Díaz, S.; Bobadilla González, J.

    2012-01-01

    Con el propósito de evaluar el humus de lombriz roja californiana Eisenia foetida como biofertilizante para el crecimiento poblacional de dos microalgas marinas, fueron cultivadas Tetraselmis tetrathele y Chaetoceros muelleri en agua de mar enriquecida con cuatro diluciones (50; 200; 350 y 500 mL) de extracto líquido de humus. La especie T. tetrathele, cultivada en la dilución de 200 mL, no mostró diferencias con el patrón medio f/2 Guillard para los parámetros: concentración celu...

  14. Water relations of field-grown grapevines in the São Francisco Valley, Brazil, under different rootstocks and irrigation strategies Relações hídricas de videiras cultivadas no Vale do São Francisco sob diferente porta-enxertos e estratégias de irrigação

    Directory of Open Access Journals (Sweden)

    Claudia Rita de Souza

    2009-08-01

    Full Text Available There is an increased demand for high quality winegrapes in the São Francisco Valley, a new wine producing area in Brazil. As the grape quality is closely linked to the soil water status, understanding the effects of rootstock and irrigation management on grapevine water relations is essential to optimize yield and quality. This study was carried out to investigate the effects of irrigation strategies and rootstocks on water relations and scion vigour of field-grown grapevines in Petrolina, Pernambuco state, Brazil. The cultivars used as scions are Moscato Canelli and Syrah, both grafted onto IAC 572 and 1103 Paulsen rootstocks. The following water treatments were used: deficit irrigation, with holding water after veraison; and partial root-zone drying, supplying (100% of crop evapotranspiration of the water loss to only one side of the root system after fruit set, alternating the sides periodically (about 24 days. In general, all treatments had values of pre-dawn leaf water potential higher than -0.2 MPa, suggesting absence of water stress. The vine water status was more affected by rootstock type than irrigation strategies. Both cultivars grafted on IAC 572 had the highest values of midday leaf water potential and stem water potential, measured on non-transpiring leaves, which were bagged with both plastic sheet and aluminum foil at least 1 h before measurements. For both cultivars, the stomatal conductance (g s, transpiration (E and leaf area index (LAI were also more affected by roostsotck type than by irrigation strategies. The IAC 572 rootstock presented higher g s, E and LAI than the 1103 Paulsen. Differences in vegetative vigor of the scion grafted onto IAC 572 rootstocks were related to its higher leaf specific hydraulic conductance and deeper root system as compared to the 1103 Paulsen, which increased the water-extraction capability, resulting in a better vine water status.Existe aumento na demanda por vinhos de alta qualidade no

  15. Fungal parasites infect marine diatoms in the upwelling ecosystem of the Humboldt current system off central Chile.

    Science.gov (United States)

    Gutiérrez, Marcelo H; Jara, Ana M; Pantoja, Silvio

    2016-05-01

    This is the first report of fungal parasitism of diatoms in a highly productive coastal upwelling ecosystem, based on a year-round time series of diatom and parasitic Chytridiomycota abundance in the Humboldt Current System off Chile (36°30.80'S-73°07.70'W). Our results show co-variation in the presence of Skeletonema, Thalassiosira and Chaetoceros diatoms with attached and detached chytrid sporangia. High abundance of attached sporangia was observed during the austral spring, coinciding with a predominance of Thalassiosira and Skeletonema under active upwelling conditions. Towards the end of austral spring, a decreasing proportion of attached sporangia was accompanied by a decline in abundance of Skeletonema and Thalassiosira and the predominance of Chaetoceros, suggesting specificity and host density dependence of chytrid infection. The new findings on fungal parasitism of diatoms provide further support for the inclusion of Fungi in the current model of the role played by the marine microbial community in the coastal ocean. We propose a conceptual model where Fungi contribute to controlling the dynamics of phytoplankton populations, as well as the release of organic matter and the transfer of organic carbon through the pelagic trophic web in coastal upwelling ecosystems. PMID:26914416

  16. Quantification of diatom gene expression in the sea by selecting uniformly transcribed mRNA as the basis for normalization.

    Science.gov (United States)

    Kang, Lee-Kuo; Tsui, Feng-Hsiu; Chang, Jeng

    2012-09-01

    To quantify gene expressions by quantitative reverse transcription-PCR (Q-RT-PCR) in natural diatom assemblages, it is necessary to seek a biomass reference specific to the target species. Two housekeeping genes, TBP (encoding the TATA box-binding protein) and EFL (encoding the translation elongation factor-like protein), were evaluated as candidates for reference genes in Q-RT-PCR assays. Transcript levels of TBP and EFL were relatively stable under various test conditions including growth stages, light-dark cycle phases, and nutrient stresses in Skeletonema costatum and Chaetoceros affinis, and TBP expression was more stable than that of EFL. Next, the sequence diversity of diatom assemblages was evaluated by obtaining 32 EFL and 29 TBP homologous gene fragments from the East China Sea (ECS). Based on sequence alignments, EFL and TBP primer sets were designed for Chaetoceros and Skeletonema groups in the ECS. An evaluation of primer specificity and PCR efficiency indicated that the EFL primer sets performed better. To demonstrate the applicability of EFL primer sets in the ECS, they were employed to measure mRNA levels of the FcpB (fucoxanthin-chlorophyll protein) gene in diatoms. The results correctly revealed prominent diel variations in FcpB expression and confirmed EFL as a good reference gene. PMID:22706063

  17. 三沙湾渔业水域理化因子与赤潮生物的关系研究%Distribution features and relation of red tide organisms environment factors in Sansha Bay

    Institute of Scientific and Technical Information of China (English)

    郑钦华

    2013-01-01

    根据2009年和2010年4~10月份对三沙湾海域生态环境调查,共鉴定浮游植物118种,其中硅藻门有36属93种,甲藻门12属25种,主要的优势种为中肋骨条藻(Skeletonema costatum)、诺氏海链藻(Thalassiosira nordenskiotdi)、具槽直链藻(Melosira sulcata)、旋链角毛藻(Chaetoceros curvisetus)、冕孢角毛藻(Chaetoceros subsecumdus)、柔弱拟菱形藻(Pseudo-nitzschia delicatissma)及东海原甲藻(Prorocentrum donghaiense).回归相关性分析表明,湾内浮游植物的分布季节和丰度受到多种环境理化因子的影响,水体pH、DO、COD、Chl-a对赤潮发生期间环境状况及赤潮的发生和发展具有明显的指示作用;尤其在6~8月间与赤潮生物细胞数之间存在显著性相关关系.

  18. Assessment of endemic microalgae as potential food for Artemia franciscana culture

    Directory of Open Access Journals (Sweden)

    Juan M Pacheco-Vega

    2015-03-01

    Full Text Available In this study, five microalgal strains were isolated from Bahía de La Paz, Baja California Sur, Mexico and identified as Grammatophora sp., Navícula sp., Rhabdonema sp., Schizochytrium sp., and Nitzschia sp., and their evaluation as potential food for Artemia franciscana. The isolated strains were cultured outdoors and harvested after four days. Chaetoceros muelleri was cultured under laboratory conditions and used as control. The protein, lipid, and carbohydrate composition and the fatty acid profiles of the strains were determined by gas chromatography. To assess the effect of microalgal strains on A. franciscana, decapsulated cysts were cultured at outdoor conditions in 15 L containers. The experiment was conducted for twelve days. Samples from the five different feeding treatments were taken at the beginning and end of the experiment to assess number, size, and weight of Artemia larvae. Treatment with Rhabdonema sp. showed larvae with a lower percentage of polyunsaturated fatty acids (PUFAs while Grammatophora sp. showed those with the greatest PUFA proportion, even more than those fed Chaetoceros muelleri (control. Larvae consuming Schizochytrium sp. had no docosahexanoic (DHA nor eicosapentaenoic (EPA fatty acid content. Growth and survival of A. franciscana did not show significant differences among feed treatments, except when it was fed Nitzschia sp., showing lower survival and dry weight. Treatment based on Schizochytrium sp. and Rhabdonema sp. had a greater A. franciscana size but reduced dry weight; additional tests including two or more algal species for every treatment should be carried out to determine the best yield.

  19. Discrimination of phytoplankton classes using characteristic spectra of 3D fluorescence spectra

    Science.gov (United States)

    Zhang, Qian-Qian; Lei, Shu-He; Wang, Xiu-Lin; Wang, Lei; Zhu, Chen-Jian

    2006-02-01

    The discrimination of phytoplankton classes using the characteristic fluorescence spectra extracted from three-dimensional fluorescence spectra was investigated. Single species cultures of 11 phytoplankton species, representing 5 major phytoplankton divisions, were used. The 3D fluorescence spectra of the cultures grown at different temperatures (20 and 15 °C) and illumination intensities (140, 80 and 30 μM m -2 s -1) were measured and their feature extraction methods were explored. Ordering Rayleigh and Raman scattering data as zero, the obtained excitation-emission matrices were processed by both singular value decomposition (SVD) and trilinear decomposition methods. The resulting first principal component can be regarded as the characteristic spectrum of the original 3D fluorescence spectrum. The analysis shows that such characteristic spectra have a discriminatory capability. At different temperatures, the characteristic spectra of Isochrysis galbana, Platymonas helgolanidica and Skeletonema costatuma have high degrees of similarity to their own species samples, while the spectra similarities of Alexandrium tamarense, Prorocentrum dentatum, Pseudo-nitzschia pungens, Chaetoceros curvisetus, Ch. Debilis, Ch. Didymus and Synechococcus sp. are not as significant as the other three species. C. curvisetus, Ch. Debilis and Ch. Didymus, belonging to genus Chaetoceros, have identical spectra and cannot be discriminated at all. Regarding all six diatom species as one class, the average discriminant error rate is below 9%. It is worth mentioning that the diatom class can be distinguished from A. tamarense and P. dentatum, which belong to Dinophyta.

  20. Genetic sexing strains for four species of insects

    International Nuclear Information System (INIS)

    Genetic sexing strains were assembled by using classical genetic and cytogenetic techniques for four medically important species of insects. Male linked reciprocal translocations were used to impose pseudolinkage of sex and selectable genes (shown in parentheses) for Anopheles albimanus (propoxur resistance), Anopheles quadrimaculatus sp. A (malathion resistance), Stomoxys calcitrans (dieldrin resistance; malathion resistance, and black pupa), and Musca domestica (black pupa). These strains would be of great value in implementation of the sterile insect technique for control of these species because the females can either be killed in the egg stage (in the case of insecticide resistance as the selectable gene) or they can be separated from the males and thus excluded from releases. (author). 13 refs

  1. Exploratory trial to determine the efficacy of the PYthon and the PYthon Magnum slow-release insecticide ear tags for the control of midges (Culicoides spp.), attacking sheep and cattle and flies attacking cattle.

    Science.gov (United States)

    Goosen, H; de Vries, P J T; Fletcher, M G

    2012-08-01

    This study investigated the prophylactic action of the chemical combination zeta-cypermethrin and piperonyl butoxide, administered by means of slow-release insecticide-impregnated ear tags, against biting midges (Culicoides spp) attacking sheep and against midges, horn flies (Haematobia irritant), stable flies (Stomoxys calcitrans), and houseflies (Musca domestica) attacking cattle. Treated sheep and cattle were protected 100 percent against blood-feeding midges for two months and there was a clear reduction in the number of midges collected from treated animals. Three days after the ear tags were attached to cattle, the number of horn flies on the cattle was reduced to practically zero and remained at a low level until the end of the trial (day 85). There was also a strong reduction in the numbers of stable flies and houseflies counted. PMID:22930983

  2. Transferability of HIV by arthropods supports the hypothesis about transmission of the virus from apes to man

    Science.gov (United States)

    Eigen, Manfred; Kloft, Werner; Brandner, Gerhard

    2002-03-01

    The primate Pan troglodytes troglodytes, a chimpanzee subspecies, has recently been defined as a natural animal host of the human immunodeficiency virus (HIV). Apes are traditionally hunted in Africa and are offered for sale in open-air meat markets. The bloody carcasses are regularly covered with blood-feeding flies, amongst them possibly the stable fly (Stomoxys calcitrans L.), a cosmopolitically occurring biting fly. This fly is the effective vector for the retrovirus causing equine leukemia. According to laboratory experiments, the infectivity of ingested HIV is not reduced in the regurgitates of this fly. These findings are combined to explain the mechanism for a possible primary transmission of HIV from ape to man.

  3. Behavioural responses of stable flies to cattle manure slurry associated odourants.

    Science.gov (United States)

    Tangtrakulwanich, K; Albuquerque, T A; Brewer, G J; Baxendale, F P; Zurek, L; Miller, D N; Taylor, D B; Friesen, K A; Zhu, J J

    2015-03-01

    Stable flies (Stomoxys calcitrans [Diptera: Muscidae] L.) are blood-feeding synanthropic pests, which cause significant economic losses in livestock. Stable fly antennae contain olfactory sensilla responsive to host and host environment-associated odours. Field observation indicated that the abundance of stable flies increased significantly in grasslands or crop fields when cattle manure slurry was applied. Major volatile compounds emanating from manure slurry were collected and identified. Behavioural responses of stable flies to those compounds were investigated in laboratory bioassays and field-trapping studies. Results from olfactometer assays revealed that phenol, p-cresol and m-cresol were attractive to adult stable flies. When tested individually, attraction was higher with lower dosages. Stable flies were most attracted to blends of phenol and m-cresol or p-cresol. Traps with binary blend lures caught more stable flies in field trials as well. PMID:25557192

  4. Salivary gland hypertrophy virus of house flies in Denmark: Prevalence, host range, and comparison with a Florida isolate

    DEFF Research Database (Denmark)

    Geden, C. J.; Steenberg, T.; Lietze, V.-U.;

    2011-01-01

    House flies (Musca domestica) infected with Musca domestica salivary gland hypertrophy virus (MdSGHV) were found in fly populations collected from 12 out of 18 Danish livestock farms that were surveyed in 2007 and 2008. Infection rates ranged from 0.5% to 5% and averaged 1.2%. None of the stable...... flies (Stomoxys calcitrans), rat-tail maggot flies (Eristalis tenax) or yellow dung flies (Scathophaga stercoraria) collected from MdSGHV-positive farms displayed characteristic salivary gland hypertrophy (SGH). In laboratory transmission tests, SGH symptoms were not observed in stable flies, flesh...... flies (Sarcophaga bullata), black dump flies (Hydrotaea aenescens), or face flies (Musca autumnalis) that were injected with MdSGHV from Danish house flies. However, in two species (stable fly and black dump fly), virus injection resulted in suppression of ovarian development similar to that observed in...

  5. Dicty_cDB: Contig-U09065-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ection 1... 36 8.7 10 ( CU280045 ) S.lycopersicum DNA sequence from clone SL_MboI-98... 38 8.8 5 ( AY068783 ) Schmidtea mediterran...lone list U09065 List of clone(s) est1= SFH875F ,1,470 est2= SFH875Z ,471,1180 Translated Amino Acid sequence cwptgia...348( CR382131 |pid:none) Yarrowia lipolytica strain CLIB... 129 7e-31 CU633900_534( CU633900 |pid:none) Podospora ans...... 118 5e-28 CU928171_8( CU928171 |pid:none) Kluyveromyces thermotolerans strai....mRNA fo... 42 0.033 EZ048843_1( EZ048843 |pid:none) TSA: Stomoxys calcitrans SC-4-2-3 ... 42 0.033 AE014297_

  6. Dihydronepetalactones deter feeding activity by mosquitoes, stable flies, and deer ticks.

    Science.gov (United States)

    Feaster, John E; Scialdone, Mark A; Todd, Robin G; Gonzalez, Yamaira I; Foster, Joseph P; Hallahan, David L

    2009-07-01

    The essential oil of catmint, Nepeta cataria L., contains nepetalactones, that, on hydrogenation, yield the corresponding dihydronepetalactone (DHN) diastereomers. The DHN diastereomer (4R,4aR,7S,7aS)-4,7-dimethylhexahydrocyclopenta[c]pyran-1(3H)-one, DHN 1) was evaluated as mosquito repellent, as was the mixture of diastereomers {mostly (4S,4aR,7S,7aR)-4,7-dimethylhexahydrocyclopenta[c]pyran-1(3H)-one, DHN 2} present after hydrogenation of catmint oil itself. The repellency of these materials to Aedes aegypti L. and Anopheles albimanus Wiedemann mosquitoes was tested in vitro and found to be comparable to that obtained with the well-known insect repellent active ingredient N,N-diethyl-3-methylbenzamide (DEET). DHN 1 and DHN 2 also repelled the stable fly, Stomoxys calcitrans L., in this study. DHN 1, DHN 2, and p-menthane-3,8-diol (PMD), another natural monoterpenoid repellent, gave comparable levels of repellency against An. albimanus and S. calcitrans. Laboratory testing of DHN 1 and DHN 2 using human subjects with An. albimanus mosquitoes was carried out. Both DHN 1 and DHN 2 at 10% (wt:vol) conferred complete protection from bites for significant periods of time (3.5 and 5 h, respectively), with DHN2 conferring protection statistically equivalent to DEET. The DHN 1 and DHN 2 diastereomers were also efficaceous against black-legged tick (Ixodes scapularis Say) nymphs. PMID:19645285

  7. Controle químico da forma galícola da filoxera Daktulosphaira vitifoliae (Fitch, 1856 (Hemiptera: Phylloxeridae na cultura da videira Chemical control of grape phylloxera Daktulosphaira vitifoliae (Fitch, 1856 leaf form (Hemiptera: Phylloxeridae on vineyards

    Directory of Open Access Journals (Sweden)

    Marcos Botton

    2004-10-01

    Full Text Available A filoxera Daktulosphaira vitifoliae (Fitch, 1856 (Hemiptera: Phylloxeridae é considerada a principal praga da videira. O inseto se alimenta da parte aérea e raízes sendo que os maiores prejuízos são observados em raízes de Vitis vinifera cultivada como pé-franco. O dano nas folhas é importante em viveiros, quando o ataque ocorre nos ramos utilizados como porta-enxertos, resistentes à forma radícola. Este trabalho foi realizado com o objetivo de selecionar inseticidas que possam ser empregados como substitutos aos fosforados e piretróides no manejo da forma galícola da filoxera. Os inseticidas imidacloprid, thiamethoxam, acephate, abamectin, deltamethrin e fenitrothion, foram avaliados em condições de campo, sob infestação natural, em plantas matrizes do porta-enxerto Paulsen 1103. Imidacloprid (Provado 200 SC, 40mL 100L-1 e thiamethoxam (Actara 250 WG, 30g 100L-1 reduziram as injúrias causadas pela forma galícola da filoxera nos ponteiros em nível superior a 90%, proporcionando controle superior aos inseticidas deltamethrin (Decis 25 CE, 40mL 100L-1 e fenitrothion (Sumithion 500 CE, 150 mL/100L considerados referência no controle do inseto. Os inseticidas acephate (Orthene 750 BR, 100g 100L-1 e abamectin (Vertimec 18 CE, 80mL 100L-1 não foram eficientes.Grape phylloxera Daktulosphaira vitifoliae (Fitch, 1856 (Hemiptera: Phylloxeridae is the main grape pest. Adults and nymphs feeds on leaves and roots but major damage is observed on roots of own rooted Vitis vinifera. Damage on leaves is important in root stock nurseries where chemical control is necessary. This study was conducted to evaluate insecticides to control the leaf form in a Paulsen 1103 nursery in field condictions. Imidacloprid (Provado 200 SC, 40mL 100L-1 and thiamethoxam (Actara 250 WG, 30g 100L-1 reduced foliar damage in more than 90%, providing better control than deltamethrin (Decis 25 CE, 40mL 100L-1 and fenitrothion (Sumithion 500 CE, 150mL 100L-1 current

  8. Sparse Matrix Decompositions and Graph Characterizations

    CERN Document Server

    Khare, Kshitij

    2011-01-01

    The question of when zeros (i.e., sparsity) in a positive definite matrix $A$ are preserved in its Cholesky decomposition, and vice versa, was addressed by Paulsen et al. in the Journal of Functional Analysis (85, pp151-178). In particular, they prove that for the pattern of zeros in $A$ to be retained in the Cholesky decomposition of $A$, the pattern of zeros in $A$ has to necessarily correspond to a chordal (or decomposable) graph associated with a specific type of vertex ordering. This result therefore yields a characterization of chordal graphs in terms of sparse positive definite matrices. It has also proved to be extremely useful in probabilistic and statistical analysis of Markov random fields where zeros in positive definite correlation matrices are intimately related to the notion of stochastic independence. Now, consider a positive definite matrix $A$ and its Cholesky decomposition given by $A = LDL^T$, where $L$ is lower triangular with unit diagonal entries, and $D$ a diagonal matrix with positive...

  9. Note: A top-view optical approach for observing the coalescence of liquid drops

    Science.gov (United States)

    Wang, Luhai; Zhang, Guifu; Wu, Haiyi; Yang, Jiming; Zhu, Yujian

    2016-02-01

    We developed a new device that is capable of top-view optical examination of the coalescence of liquid drops. The device exhibits great potential for visualization, particularly for the early stage of liquid bridge expansion, owing to the use of a high-speed shadowgraph technique. The fluid densities of the two approaching drops and that of the ambient fluid are carefully selected to be negligibly different, which allows the size of the generated drops to be unlimitedly large in principle. The unique system design allows the point of coalescence between two drops to serve as an undisturbed optical pathway through which to image the coalescence process. The proposed technique extended the dimensionless initial finite radius of the liquid bridge to 0.001, in contrast to 0.01 obtained for conventional optical measurements. An examination of the growth of the bridge radius for a water and oil-tetrachloroethylene system provided results similar to Paulsen's power laws of the inertially limited viscous and inertial regimes. Furthermore, a miniscule shift in the center of the liquid bridge was detected at the point of crossover between the two regimes, which can be scarcely distinguished with conventional side-view techniques.

  10. Pruning management of Chardonnay grapevines at high altitude in Brazilian southeast

    Directory of Open Access Journals (Sweden)

    Tania dos Reis Mendonça

    2016-03-01

    Full Text Available ABSTRACT The agronomical responses of Chardonnay, a variety indicated for sparkling wine production, is influenced by the vineyard management and the edaphoclimatic conditions of the region. The objective of this study was to evaluate the effects of two pruning types (Royat and double Guyot on vegetative and reproductive development of Chardonnay vine growing at high altitude in the Brazilian southeastern region. The experiment was carried out in a commercial vineyard located at 1,280 m of altitude in Divinolândia, São Paulo State, Brazil. The Chardonnay vines (clone 96, grafted onto 1103 Paulsen rootstock and trained in a vertical shoot positioning trellis system, were assessed. Vegetative vigor, bud fruitfulness, production and physicochemical composition of grapes were evaluated during 2014 and 2015 growing seasons. The Royat pruning induced higher vegetative vigor and increased the bud fruitfulness, the cluster number and the productivity of Chardonnay vine when compared to Guyot pruning. Even though the increase on yield was observed, there was no effect of pruning type on grape final quality. Therefore, the choice of pruning method in function of variety genetic characteristics and their interaction with environment can optimize the vineyard profitability. In the Brazilian southeast, the Royat system is the most suitable one to grow Chardonnay for sparkling wines production.

  11. 厦门东侧海域浮游植物的种类组成与分布%Species composition and distribution of phytoplankton in eastern Xiamen waters

    Institute of Scientific and Technical Information of China (English)

    杨清良; 林更铭; 蔡秉及

    2000-01-01

    共鉴定厦门东侧海域浮游植物43属111种.其主体是广温性种类(56种),占浮游植物总种数的50%.主要优势种的季节性演替明显.四季浮游植物的平均细胞总量达36 500千个/m3,最重要的优势种是旋链角毛藻(Chaetoceros curvisetus)(占总量的53.3%)和中肋骨条藻(Skeletonema costatum)(占20.0%).浮游植物的繁盛时期在春、夏两季,但高峰期出现在春季,不同于相邻的厦门外港和厦门西港.

  12. Ecological composition and distribution of the diatoms from the Laguna Superior, Oaxaca, Mexico.

    Science.gov (United States)

    Moreno-Ruiz, José Luis; Tapia-Garcia, Margarito; Licea, Sergio; Figueroa-Torres, María Guadalupe; Esquivel, Alfonso; Herrera-Galindo, Jorge Eduardo; González-Fernández, José Manuel; González-Macias, Maria Del Carmen

    2011-07-01

    A taxonomic study of diatoms was carried out in a tropical coastal lagoon. Material for this study consists of water samples obtained from February-March 1992 to November-December 2000. Qualitative and quantitative analyses showed the presence of 373 taxa of which the families Bacillariaceae (67 species) and Chaetocerotaceae (37 species) were the most abundant groups. The species Skeletonema costatum, Chaetoceros curvisetus, Coscinodiscus radiatus var. radiatus, Ditylum brightwellii, Thalassiosira eccentrica and Entomoneis alata were found associated with moderate water quality and forming blooms. In addition, a regional comparison between Mexico and South America of the identified species is given. For practical handling, indicative values obtained from their ecological composition are incorporated as well as a code of the floristic list. Achecklist of the species and their occurrence are given. PMID:22315822

  13. Seasonal distribution and correlates of transparent exopolymer particles (TEP) in the waters surrounding mangroves in the Sundarbans

    Science.gov (United States)

    Chowdhury, Chumki; Majumder, Natasha; Jana, Tapan Kumar

    2016-06-01

    In situ concentration of transparent exopolymer particles (TEP) are usually associated with phytoplankton dominated by diatoms and their release of precursor polysaccharide material in the aquatic system. Here, we present temporal data on TEP variation and related habitat parameters for waters surrounding mangroves in the Sundarbans located at the coastal boundary of the Ganges River delta. Over three study years (2009-2011), TEP concentration was highest during the post-monsoon period and was mainly a function of phytoplankton production. The most common diatom species (by percentage of relative abundance) were Skeletonema cf. costatum (Cleve 1873), Ditylum brightwellii (Gosse 1850), and Chaetoceros sp. During the post-monsoon, when phytoplankton was abundant TEP/Chl-a ratio was relatively low and as nutrients depleted from water, phytoplankton biomass declined subsequently, increasing mean TEP/Chl-a ratio in the pre-monsoon.

  14. Diatom associations in shelf waters off Paraná State, Southern Brazil: annual variation in relation to environmental factors

    Directory of Open Access Journals (Sweden)

    Luciano Felício Fernandes

    2004-03-01

    Full Text Available The seasonal variation of diatoms in the inshore waters off Paraná State, Southern Brazil was investigated to analyse their temporal dynamics and to detect the main environmental constraints of the planktonic community. Biomass peaks occurred from May to August and from December to March. Among the microplanktonic diatoms, Cerataulina pelagica, Chaetoceros spp., Dactyliosolen fragilissimus, Guinardia striata, Lauderia annulata, Leptocylindrus spp., Pseudo-nitzschia cf. delicatissima, P. australis, Rhizosolenia spp., Skeletonema costatum and Thalassionema nitzschioides were dominant species. Nanoplanktonic diatoms were dominated by Naviculaceae, Nitzschia spp., Thalassiosira spp. and Chaetoceros cf. tenuissimus. Concentrations of most of the species decreased during and just after the blooms of Phaeocystis pouchetii in September and of Coscinodiscus wailesii in April. Based on cluster analysis and interpretations of the environmental parameters monitored, six diatom associations were discerned. Four main environmental factors were attributed as the determinants for the grouping: (a the stronger influence of the tropical oligotrophic waters of the Brazil Current in spring/summer, (b the alternation between dry and rainy (nutrient-richer seasons, (c the influence of subantarctic waters mixed with coastal ones in fall/winter, bringing cold species and promoting the growth of autochthonous species, and (d the blooms of nanoplanktonic (Phaeocystis and microplanktonic (C. wailesii species.A variação sazonal das diatomáceas em águas neríticas do estado do Paraná, Sul do Brasil, foi investigada para analisar sua dinâmica temporal e detectar as principais forçantes ambientais da comunidade planctônica. Picos de biomassa ocorreram de Maio a Agosto e de Dezembro a Março. As espécies dominantes foram Cerataulina pelagica, Chaetoceros spp., Dactyliosolen fragilissimus, Guinardia striata, Lauderia annulata, Leptocylindrus spp., Pseudo-nitzschia cf

  15. GROWING DOMINANT SPECIES OF MICROALGAE IN NORTH EASTERN BLACK SEA

    Directory of Open Access Journals (Sweden)

    Lifanchuk A. V.

    2013-11-01

    Full Text Available In this article we present data on the effect of addition of mineral nutrition elements in the structure of the phytoplankton community in the north-eastern part of the Black Sea in the different seasons. Experimental studies have shown that the increase in biomass of microalgae occurs at the simultaneous addition of nitrogen and phosphorus in the accumulative cultures. In the spring can get biomass Emiliania huxleyi, P.pseudodelicatissima, Chaetoceros curvisetus and Skeletonema costatum, in the summer – E. huxleyi, C. curvisetus, P.pseudodelicatissima, S.costatum, Thalassionema nitzschioides, Leptocylindrus danicus, Dactyliosolen fragilissimus, Proboscia alata, Pseudosolenia calcar-avis, in the autumn - C. curvisetus, S.costatum, Th. nitzschioides, L. danicus, D. fragilissimus

  16. The evaluation of fish farming impact by nutrient content and chlorophyll A in Mala Lamljana bay

    Directory of Open Access Journals (Sweden)

    Jelic-Mrcelic Gorana

    2013-01-01

    Full Text Available This paper offers a brief review of the impacts of fish farming on the nutrient content and chlorophyll a in Mala Lamljana Bay, Croatia. Local loading of nitrogen and phosphorous compounds in fish farms can be very significant and can represent the largest source of N and P in a given area. Low N and P concentrations, low chlorophyll a concentration and a great variety of phytoplankton species were found in the bay, despite the high nutrient loading during the long history of farming in the bay. The phytoplankton community consisted mostly of diatoms and partly of dinoflagellates. Skeletonema costatum and Chaetoceros compressus were the dominant species (90% in summer chlorophyll, which is typical for Middle Adriatic oligotrophic coastal waters. Nevertheless, further studies are required to determine changes in water column factors and planktonic communities in this area.

  17. Microzooplankton Grazing Impact on Phytoplankton Blooms in the Coastal Seawater of the Southern Crimea (Black Sea

    Directory of Open Access Journals (Sweden)

    L.V. Stelmakh

    2013-04-01

    Full Text Available The investigation of seasonal dynamics of microzooplankton specific grazing rate was carried out in the near-shore sea off the southern Crimea (Black Sea during 2006~2007 and 2010. It is shown that microzooplankton grazing depended on the abundance and quality of prey. The favorite prey items were diatoms Skeletonema costatum and Chaetoceros spp. When microzooplankton grazed less than 80% of the primary production, the peaks of phytoplankton biomass were recorded in this study. The average annual removal of primary production by microzooplankton was estimated as weighty as 65%. Such estimated values indicate the key role of the microzooplankton in exporting matter and energy from phytoplankton to higher trophic levels.

  18. The influence of extracellular compounds produced by selected Baltic cyanobacteria, diatoms and dinoflagellates on growth of green algae Chlorella vulgaris

    Science.gov (United States)

    Żak, Adam; Kosakowska, Alicja

    2015-12-01

    Secondary metabolites produced by bacteria, fungi, algae and plants could affect the growth and development of biological and agricultural systems. This natural process that occurs worldwide is known as allelopathy. The main goal of this work was to investigate the influence of metabolites obtained from phytoplankton monocultures on the growth of green algae Chlorella vulgaris. We selected 6 species occurring in the Baltic Sea from 3 different taxonomic groups: cyanobacteria (Aphanizomenon flos-aquae; Planktothrix agardhii), diatoms (Thalassiosira pseudonana; Chaetoceros wighamii) and dinoflagellates (Alexandrium ostenfeldii; Prorocentrum minimum). In this study we have demonstrated that some of selected organisms caused allelopathic effects against microalgae. Both the negative and positive effects of collected cell-free filtrates on C. vulgaris growth, chlorophyll a concentration and fluorescence parameters (OJIP, QY, NPQ) have been observed. No evidence has been found for the impact on morphology and viability of C. vulgaris cells.

  19. Simulated terrestrial runoff triggered a phytoplankton succession and changed seston stoichiometry in coastal lagoon mesocosms.

    Science.gov (United States)

    Deininger, A; Faithfull, C L; Lange, K; Bayer, T; Vidussi, F; Liess, A

    2016-08-01

    Climate change scenarios predict intensified terrestrial storm runoff, providing coastal ecosystems with large nutrient pulses and increased turbidity, with unknown consequences for the phytoplankton community. We conducted a 12-day mesocosm experiment in the Mediterranean Thau Lagoon (France), adding soil (simulated runoff) and fish (different food webs) in a 2 × 2 full factorial design and monitored phytoplankton composition, shade adaptation and stoichiometry. Diatoms (Chaetoceros) increased four-fold immediately after soil addition, prymnesiophytes and dinoflagellates peaked after six- and 12 days, respectively. Soil induced no phytoplankton shade adaptation. Fish reduced the positive soil effect on dinoflagellates (Scripsiella, Glenodinium), and diatom abundance in general. Phytoplankton community composition drove seston stoichiometry. In conclusion, pulsed terrestrial runoff can cause rapid, low quality (high carbon: nutrient) diatom blooms. However, bloom duration may be short and reduced in magnitude by fish. Thus, climate change may shift shallow coastal ecosystems towards famine or feast dynamics. PMID:27209121

  20. Pyrolytic characteristics of biodiesel prepared from lipids accumulated in diatom cells with growth regulation.

    Science.gov (United States)

    Cheng, Jun; Feng, Jia; Ge, Tingting; Yang, Weijuan; Zhou, Junhu; Cen, Kefa

    2015-08-01

    Dynamic compositions of lipids accumulated in two diatoms Chaetoceros gracilis and Nitzschia closterium cultured with nitrogen and silicon deprivation were studied. It was found that short-chain fatty acids (C14-C16) content was much higher than long-chain fatty acids (C18-C20) content in lipids of two diatoms. The pyrolytic characteristics of biodiesel made from two diatoms and two plant seeds were compared by thermogravimetric analysis. The highest activation energy of 46.68 kJ mol(-1) and the minimum solid residue of 25.18% were obtained in the pyrolysis of biodiesel made from C. gracilis cells, which were cultured with 0.5 mmol L(-1) of nitrogen (no silicon) and accumulated the minimum polyunsaturated fatty acid (C20:5). The pyrolysis residue percentage of C. gracilis biodiesel was lower than that of N. closterium biodiesel and higher than those of plant (Cormus wilsoniana and Pistacia chinensis) biodiesels. PMID:25782618

  1. Persistent blooms of surf diatoms along the pacific coast U. S. A. I. physical characteristics of the coastal region in relation to the distribution and abundance of the species

    Energy Technology Data Exchange (ETDEWEB)

    Garver, J.L.; Lewin, J.

    1981-01-01

    The surf diatom populations at thirteen beaches along the Oregon and Washington coast were studied from June 1977 through August 1978. Chaetoceros armatum T. West and Asterionella socialis Lewin and Norris, the two species responsible for the blooms, were present in the surf along beaches between Point Grenville, Washington, and Cape Blanco, Oregon. On the basis of the cell densities of these two species, the beaches were arranged into four distinct groups. Discriminant analysis showed that the four groups could also be completely separated by three discriminant functions composed of four physical variables: offshore bottomslope, per cent chlorite, per cent montmorillonite and beach length. The absence of surf diatoms at two beaches south of Cape Blanco can probably be explained by the unsuitable physical conditions along the coast south of the Cape.

  2. Phenotypic plasticity of southern ocean diatoms: key to success in the sea ice habitat?

    Directory of Open Access Journals (Sweden)

    Olivia Sackett

    Full Text Available Diatoms are the primary source of nutrition and energy for the Southern Ocean ecosystem. Microalgae, including diatoms, synthesise biological macromolecules such as lipids, proteins and carbohydrates for growth, reproduction and acclimation to prevailing environmental conditions. Here we show that three key species of Southern Ocean diatom (Fragilariopsis cylindrus, Chaetoceros simplex and Pseudo-nitzschia subcurvata exhibited phenotypic plasticity in response to salinity and temperature regimes experienced during the seasonal formation and decay of sea ice. The degree of phenotypic plasticity, in terms of changes in macromolecular composition, was highly species-specific and consistent with each species' known distribution and abundance throughout sea ice, meltwater and pelagic habitats, suggesting that phenotypic plasticity may have been selected for by the extreme variability of the polar marine environment. We argue that changes in diatom macromolecular composition and shifts in species dominance in response to a changing climate have the potential to alter nutrient and energy fluxes throughout the Southern Ocean ecosystem.

  3. A triphase red tide in Tong'an Bay of Xiamen Seas and its causes analysis%厦门同安湾海域一次三相型赤潮及其成因分析

    Institute of Scientific and Technical Information of China (English)

    俞秀霞

    2012-01-01

    通过监视监测2011年7月26日-8月7日发生在厦门同安湾的赤潮,对赤潮发生时的水文气象、化学、生物因子等进行分析。结果表明,本次赤潮为三相混合型赤潮,赤潮生物为中肋骨条藻(Skeletonema costatum)、血红哈卡藻(Akashiwo sanguinea)和角毛藻(Chaetoceros sp.),赤潮最大面积为105km2。水体的富营养化、持续的高温天气和小潮期水体的相对稳定是本次赤潮发生的基本条件,"洛坦"台风的气压影响以及降雨导致的盐度急剧下降是此次赤潮的诱因。%A red tide in Tong'an Bay of Xiamen Seas during July 26th to August 7th in 2011 was reported in this paper. Hydrological meteorological, chemistry and biological factors were analyzed in the occurrence of red tide. The results showed that this red tide with the area of 105 km2 was a hybrid triphase red tide, and the red tide species included Skeletonema costatum, Akashiwo sanguinea, Chaetoceros sp. The basic conditions of this tide were eutrophication, continuous high air temperature and the stable water body of neap tide, the air pressure due to "Luotan" typhoon and sharp decline of salinity due to rainfall also contributed to this red tide.

  4. [Analysis on characteristics of red tide in Fujian coastal waters during the last 10 years].

    Science.gov (United States)

    Li, Xue-Ding

    2012-07-01

    There were 161 red tide events collected during the last 10 years from 2001 to 2010 in Fujian coastal waters. Comprehensive analysis was performed using statistical methods and the results indicated the following characteristics of the temporal and spatial distribution of red tide in Fujian coastal waters: (1) Outbreaks of red tide often occurred between April and September, and the peak period was in May and June. Most red tide events lasted for 2 to 4 days, and the affected area was below 50 square kilometers. The first outbreak of red tide tended to occur earlier in recent years, and the lasting time became longer. (2) There were 20 species of organisms causing the red tides in Fujian coastal waters, among which 10 species were Bacillariophyta, 9 species were Dinophyta and 1 species was Protozoa. Prorocentrum donghaiense was the most frequent cause of red tides, followed by Noctiluca scintillans, Skeletonema costatum and Chaetoceros sp.. The species caused red tides obeyed the succession law and there were always new species involved. (2) In terms of spatial distribution, outbreaks of red tides mainly occurred in the coastal waters of Ningde, Fuzhou and Xiamen. The species causing red tides were Prorocentrum donghaiense and Noctiluca in the coastal waters in the north of Pingtan, Fujian Province, Skeletonema costatum and Chaetoceros in the coastal waters in the south of Pingtan, Fujian Province. The comprehensive analysis of the characteristics of red tides during the last 10 years is expected to provide scientific and reasonable basis for the prevention, reduction and forecast of red tides in Fujian coastal waters. PMID:23002593

  5. Temporal variation of diatom benthic propagules in a monsoon-influenced tropical estuary

    Science.gov (United States)

    Patil, Jagadish S.; Anil, Arga Chandrashekar

    2008-10-01

    Temporal variations in the diatom benthic propagule (DBP) community and their role in the phytoplankton community in a monsoon-affected tropical estuary, Zuari estuary, Goa (India) are presented. The DBP from the sediments was enumerated using an extinction dilution method (most probable number method), which allows estimation of resting stages through examination of germinated vegetative cells in culture. The DBP community was dominated by planktonic species belonging to the genera Skeletonema, Fragilariopsis, Thalassiosira, and Chaetoceros. Benthic propagules (BPs) of Skeletonema costatum and Fragilariopsis sp. were dominant throughout the year. Between these two species, only S. costatum showed a linear relationship between the BP and planktonic cells, indicating that this species is particularly important in coupling of pelagic and benthic ecosystems. During the onset and restart of monsoon after an intermittent break, water column was stratified, with a low-salinity layer arising from riverine discharge and precipitation at the surface and relatively cold, saline, low-oxygen waters at the bottom. Stratification favored blooming of S. costatum and Fragilariopsis sp. in nutrient-rich surface and bottom waters, respectively. The decline in these blooms ensuing nitrate depletion and salinity change resulted in an increased abundance of BP. Chaetoceros bloom was observed during the monsoon break as well as during non-monsoon period and on both the occasions the decline in bloom was coupled with freshwater discharge. During the non-monsoon season, Thalassiosira blooms were encountered subsequent to high nitrate inputs. These findings suggest that in such shallow tropical regions, physical processes during monsoon (freshwater discharge) and non-monsoon seasons (currents, waves and tides) cause resuspension of diatom BP. Since light is not a limiting factor for germination in such regions, the blooming of resuspended BP depends on nutrient availability.

  6. The effects of spring-neap tide on the phytoplankton community development in the Jiaozhou Bay,China

    Institute of Scientific and Technical Information of China (English)

    LIU Dongyan; SUN Jun; LIU Zhe; CHEN Hongtao; WEI Hao; ZHANG Jing

    2004-01-01

    The development of the phytoplankton community was studied in the Jiaozhou Bay during the spring to neap tide in August 2001, through three cruises and a 15 d continuous observation. This investigation indicates that diatom cell abundance increased sharply following the end of a spring tide, from 9 cells/cm3 to a peak of 94 cells/cm3. The dominant species composition and abundance show a quick species sequence from spring to neap tide, and the dominant species at the start phase is Skeletomena costatum, then changes to Chaetoceros curvisetus, finally it changes to Eucampia zodiacus. Silicate concentration increases during spring tide, as a result of nutrient replenishment from the water-sediment interface, its initial average concentration in neap tide is 1.39 μmol/dm3 and reached the peak average concentration of 8.40 μmol/dm3 in spring tide. But the nitrogen concentration dropped due to dilution by the low nitrogen seawater from the Huanghai Sea, its initial average concentration in neap tide is 67 μmol/dm3 and decreased to the average concentration of 54 μmol/dm3 in spring tide. The degree of silicon limitation was decreased and phytoplankton, especially diatoms, responds immediately after nutrient replenishment in the water column. Skeletonmea costatum, as one of the dominant species in the Jiaozhou Bay, shows a quicker response to nutrient availability than Eucampia zodiacus and Chaetoceros curvisetus. It is proposed that dominant species composition and water column stability synchronously determine the development of phytoplankton summer blooms in the Jiaozhou bay.

  7. The research of relationships between phytoplankton and environmental factors in artificial reef area of Haizhou Bay%海州湾人工鱼礁区浮游植物与环境因子关系的研究

    Institute of Scientific and Technical Information of China (English)

    杨柳; 张硕; 孙满昌; 张虎

    2011-01-01

    By using canonical correspondence analysis (CCA), this paper studied the relationship between phytoplankton species and its environmental factors.The species-environment biplots were drawn based on the result of CCA.The result showed that total inorganic nitrogen, water temperature and transparency were the most important factors influencing the distribution of phytoplankton species.The distribution of main dominant phytoplankton species Chaetoceros muelleri and Eucompia zoodiacus correlated strongly with phosphate.CCA can be a useful tool to understand the spatial distribution of phytoplankton species in marine ecosystems.%于2008年对海州湾人工鱼礁区进行了3个航次的理化因子和生物资源调查,应用CANOCO4.5软件对获得的浮游植物数据和环境因子数据进行典范对应分析(canonical correspondence analysis),作出物种与环境因子关系的二维排序图.根据环境因子与排序轴的相关系数,认为影响这一海区浮游植物分布的主要环境因子依次为总无机氮、水温和透明度.主要浮游植物优势种牟勒氏角毛藻(Chaetoceros muelleri)和浮动弯角藻(Eucampia zoodiacus)的分布与磷酸盐密切相关,这些优势种在鱼礁区和对照区数量上的差异导致了鱼礁区浮游植物数量要高于对照区.

  8. Some thermal effects of a simulated entrainment regime on marine plankton

    International Nuclear Information System (INIS)

    Six species of diatoms, various life stages of seven species of zooplankters, and the demersal eggs of a fish were subjected to laboratory simulations of the maximum thermal regime predicted for the Maine Yankee Atomic Power Plant. Each organism was tested from the ambient temperature(s) (AT) at which they occurred normally. These ranged from 3 to 200C. The simulated thermal regime (STR) consisted of a nearly instantaneous temperature rise (usually 140C) above AT followed by a controlled return to AT over a 3-hr period. Chaetoceros laciniosus, which suffered a complete mortality, was the only diatom species sensitive to the STR from a 3 or 150C AT. Chaetoceros lorenzianus and Skeletonema costatum, not sensitive to the STR from an AT of 150C, were sensitive from an AT of 200C; although mortalities were not complete, the lag phase preceding exponential growth in treated cultures was usually prolonged. The zooplankters and fish eggs tested from AT's of 3, 5, or 100C were not sensitive to the STR. However, zoea of the decapod crab Cancer irroratus, not sensitive to the STR from a 100C AT, were sensitive from a 150C AT. The data suggested that other factors, including crowding, salinity, and duration of exposure, may have complicated the zoea results at the 150C AT. Nauplii of the calanoid copepod, Eurytemora herdmani were all killed when tested from a 200C AT, but not from a 100C AT. Females of the archiannelid, Dinophilus conklini were tested from an AT of 200C with inconclusive results, which suggested these organisms may be sensitive to the STR from this AT. Polychaete nectochaetes and juveniles, the most tolerant group tested, showed no sensitivity to the STR from AT's ranging from 3 to 200C. (U.S.)

  9. Automatic cell object extraction of red tide algae in microscopic images

    Science.gov (United States)

    Yu, Kun; Ji, Guangrong; Zheng, Haiyong

    2016-05-01

    Extracting the cell objects of red tide algae is the most important step in the construction of an automatic microscopic image recognition system for harmful algal blooms. This paper describes a set of composite methods for the automatic segmentation of cells of red tide algae from microscopic images. Depending on the existence of setae, we classify the common marine red tide algae into non-setae algae species and Chaetoceros, and design segmentation strategies for these two categories according to their morphological characteristics. In view of the varied forms and fuzzy edges of non-setae algae, we propose a new multi-scale detection algorithm for algal cell regions based on border- correlation, and further combine this with morphological operations and an improved GrabCut algorithm to segment single-cell and multicell objects. In this process, similarity detection is introduced to eliminate the pseudo cellular regions. For Chaetoceros, owing to the weak grayscale information of their setae and the low contrast between the setae and background, we propose a cell extraction method based on a gray surface orientation angle model. This method constructs a gray surface vector model, and executes the gray mapping of the orientation angles. The obtained gray values are then reconstructed and linearly stretched. Finally, appropriate morphological processing is conducted to preserve the orientation information and tiny features of the setae. Experimental results demonstrate that the proposed methods can eff ectively remove noise and accurately extract both categories of algae cell objects possessing a complete shape, regular contour, and clear edge. Compared with other advanced segmentation techniques, our methods are more robust when considering images with different appearances and achieve more satisfactory segmentation eff ects.

  10. Écologie des stomoxes (Diptera : Muscidae au Gabon. I – Premier inventaire dans différentes zones écologiques

    Directory of Open Access Journals (Sweden)

    Mavoungou J.F.

    2008-03-01

    Full Text Available Les stomoxes (Stomoxys spp. sont des diptères hématophages, vecteurs potentiels de divers agents pathogènes. Comme ceux de la région afrotropicale en général, les stomoxes du Gabon demeurent mal connus. Pour ces raisons, une enquête entomologique a été conduite de façon transversale dans huit localités représentatives des diverses zones écologiques du Gabon. L’enquête est basée sur l’utilisation de pièges Vavoua. Divers facteurs environnementaux pouvant influer sur les captures ont été relevés et inclus dans une analyse canonique des correspondances. Au total, 15 966 stomoxes, appartenant à sept espèces ou sous-espèces, ont été capturés. Les densités apparentes (DAP, exprimées en nombre de stomoxes par piège et par jour, sont importantes dans les localités de Franceville (41, Bakoumba (40, Makokou (25 et Mouila (21. Les espèces les plus abondantes sont Stomoxys n. niger (33,4 % de l’ensemble des captures, S. transvittatus (33 % puis S. calcitrans (17 %. Les principaux facteurs qui expliquent la variabilité des captures sont le degré d’anthropisation du milieu, le faciès botanique (savane ou forêt, la présence de la faune sauvage et domestique et la nature de la couverture végétale du sol. S. calcitrans et S. n. niger sont abondants dans les zones où la présence humaine est manifeste. S. xanthomelas est inféodé aux zones forestières. S. transvittatus, S. omega, et S. inornatus sont des espèces ubiquistes. S. niger bilineatus se retrouve dans les zones de savane.

  11. Condições meteorológicas e tipo de solo na composição da uva 'Cabernet Sauvignon' Weather and soil effects on the composition of 'Cabernet Sauvignon' grape

    Directory of Open Access Journals (Sweden)

    Rodrigo Vieira Luciano

    2013-01-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos das condições meteorológicas e do tipo de solo sobre características físico-químicas e compostos fenólicos da uva 'Cabernet Sauvignon' (Vitis vinifera. O experimento foi realizado em vinhedo implantado em 2003, enxertado sobre o porta-enxerto 'Paulsen 1103' e conduzido no sistema espaldeira. No vinhedo, foram selecionados dois solos: Cambissolo Háplico e Cambissolo Húmico. O efeito das condições meteorológicas (precipitação e temperatura mínima e máxima do ar foi avaliado nas safras 2008/2009, 2009/2010 e 2010/2011. Foram determinados os atributos físicos e químicos dos solos, os teores de sólidos solúveis, a acidez titulável e o pH do mosto, bem como o índice de polifenóis totais e dos teores de antocianinas e de taninos da uva. Os fatores solo e as condições meteorológicas (safras foram arranjados em esquema fatorial 2x3. Com exceção do teor de polifenóis totais, as condições meteorológicas e o tipo de solo afetam as características físico-químicas da uva 'Cabernet Sauvignon', com efeito mais pronunciado das condições meteorológicas do que do tipo de solo. Menores precipitações e maiores amplitudes térmicas favorecem o acúmulo de sólidos solúveis na uva 'Cabernet Sauvignon'. Maiores precipitações favorecem o aumento da acidez do mosto.The objective of this work was to evaluate the effects of weather and soil type on the physicochemical characteristics and phenolic compounds of the 'Cabernet Sauvignon' grape (Vitis vinifera. The experiment was carried out in a vineyard established in 2003, grafted onto 'Paulsen 1103', and conducted in the cordon system. Two soils were selected in the vineyard: Typic Dystrudepts and Pachic Humudepts. The effect of weather (rainfall, and minimum and maximum temperature was evaluated in the seasons 2008/2009, 2009/2010, and 2010/2011. Soil physical and chemical properties, soluble solids, titratable acidity and pH of the

  12. Produtividade e composição físico-química de bagas de cultivares de uva em distintos porta-enxertos Productivity and physicochemical composition of berries of grapevine cultivars grafted onto different rootstocks

    Directory of Open Access Journals (Sweden)

    Renata Vieira da Mota

    2009-06-01

    Full Text Available O objetivo deste trabalho foi avaliar a influência de nove porta-enxertos na produção e composição química das bagas de uvas de mesa e de processamento durante o período de 2006 a 2008 em Caldas, MG. As cultivares Niágara Rosada e Folha de Figo foram enxertadas sobre 'IAC 572', 'IAC 313', 'IAC 766', '420 A', '1103 Paulsen', 'Traviú', '196-17', 'Gravesac' e 'RR 101-14' e submetidas ao delineamento em blocos ao acaso com dez tratamentos (nove porta-enxertos e o pé-franco e quatro repetições. Ambas cultivares apresentaram maior produção sobre 'IAC 572', porém com prejuízo para a qualidade das bagas que apresentaram menor relação sólidos solúveis/acidez, menor teor de antocianinas e de compostos fenólicos e maior acidez. A absorção de potássio foi mais dependente do porta-enxerto em 'Niágara Rosada'; a maior absorção foi com os porta-enxertos 'IAC 766' e 'Traviú'. Videiras enxertadas sobre '196-17' apresentaram o menor teor de potássio nas bagas. 'Niágara Rosada' apresentou produção de 9 kg por planta e elevada relação sólidos solúveis/acidez sobre 'RR 101-14', '420 A' e 'Gravesac'. Entretanto, 'Gravesac' proporcionou maior concentração de antocianinas. 'Folha de Figo' enxertada em '196-17' apresentou elevado teor de sólidos solúveis, antocianinas e fenólicos nas cascas e menor teor de acidez e fenólicos nas sementes, além de produção de 5 kg por planta, estatisticamente semelhante aos porta-enxertos mais produtivos.This work aimed at evaluating the influence of nine rootstocks on the productivity and chemical composition of table and processing grapes from 2006 to 2008 in Caldas, MG. The cultivars Niagara Rosada and Folha de Figo were grafted onto 'IAC 572', 'IAC 313', 'IAC 766', '420 A', '1103 Paulsen', 'Traviú', '196-17', 'Gravesac' and 'RR 101-14' and submitted to a randomized block design with ten treatments (nine rootstocks and ungrafted plant with four replicates. Both cultivars had higher yields

  13. Efeito do porta-enxerto no teor de nutrientes em tecidos da videira "cabernet sauvignon" Effect of rootstock on nutrient content of 'cabernet sauvignon' grapevine tissues

    Directory of Open Access Journals (Sweden)

    Alberto Miele

    2009-12-01

    Full Text Available A nutrição mineral da videira constitui-se em importante fator para a qualidade dos vinhos. Devido a isso, avaliou-se o efeito de porta-enxertos no teor de nutrientes em diferentes tecidos da videira 'Cabernet Sauvignon' (Vitis vinifera L. na Serra Gaúcha. o experimento foi conduzido durante o ciclo vegetativo de 2004/2005, com os porta-enxertos Rupestris du lot, 101-14, 3309, 420A, Kober 5BB, 161-49, So4 e Paulsen 1103, enxertados em 1993 com a cv. 'Cabernet Sauvignon'. o delineamento experimental foi em blocos ao acaso, com oito tratamentos e três repetições, sendo quatro plantas/parcela. Coletaram-se folhas - separando-se os pecíolos dos limbos -, cachos - separando-se as bagas das ráquis - e ramos, os quais foram posteriormente secados em estufa e pesados. Analisaram-se os nutrientes n, P, K, Ca e Mg. os resultados mostram que houve efeito significativo do porta-enxerto nos teores de N, P, K, Ca e Mg no limbo, pecíolo, ráquis e baga da videira 'Cabernet Sauvignon' e que este efeito variou em função do nutriente e do tecido considerado. Entretanto, não houve efeito significativo do porta-enxerto no teor desses nutrientes no ramo da videira. Além disso, a ordem de grandeza do teor dos nutrientes variou em função do tecido avaliado. Assim, os teores de n e de Ca foram maiores no limbo; os de P e K, na ráquis; e o de Mg, no pecíolo.Grapevine mineral nutrition is an important factor influencing wine quality. For this, the effect of rootstocks on the nutrient content in different tissues of 'Cabernet Sauvignon' grapevines (Vitis vinifera L. grown in the Serra Gaúcha region was evaluated. The experiment was carried out during the 2004/2005 vegetative cycle with the rootstocks Rupestris du Lot, 101-14, 3309, 420A, Kober 5BB, 161-49, SO4, and Paulsen 1103. The experimental design was in randomized blocks, with eight treatments, three replicates, four plants/plot. leaves - petioles were separated from the limbs -, clusters - berries

  14. Influência da altitude na qualidade das uvas 'Chardonnay' e 'Pinot Noir' em Minas Gerais Altitude influence on the quality of 'Chardonnay' and 'Pinot Noir' grapes in the state of Minas Gerais

    Directory of Open Access Journals (Sweden)

    Murillo de Albuquerque Regina

    2010-03-01

    Full Text Available No Sul e Sudeste brasileiros, o excesso de chuvas durante o período de maturação afeta negativamente a qualidade dos vinhos tintos. Por outro lado, estas regiões possuem potencial para a elaboração de espumantes, uma vez que, para a elaboração desta bebida, a uva é colhida antes de completar o amadurecimento. No Estado de Minas Gerais, as condições de verão chuvoso estão presentes em todas as regiões de potencial vitícola, e a variação de altitude entre elas pode exercer influência na composição das uvas. Desta forma, este estudo buscou avaliar o potencial de maturação de uvas 'Chardonnay' e 'Pinot Noir' destinadas à elaboração de espumantes em dois locais de Minas Gerais: Cordislândia (873m e Caldas (1.150m. As plantas foram enxertadas sobre 1.103 Paulsen e conduzidas em espaldeira. Foram avaliados os teores de sólidos solúveis totais, acidez total, ácidos málico e tartárico, e pH do mosto, tamanho e massa das bagas, compostos fenólicos nas cascas e sementes, antocianinas na casca e açúcares solúveis nas bagas, em duas safras consecutivas. As bagas apresentaram maior tamanho e massa quando cultivadas em Caldas. As uvas colhidas em Cordislândia apresentaram maior grau de maturação, sendo observados maior pH, maiores teores de glicose e frutose, e quantidade inferior de acidez e fenólicos totais nas sementes. Os maiores teores de ácido málico presentes nas uvas provenientes de Caldas sugerem que esta região pode ser mais indicada à produção de uvas para elaboração de vinhos espumantes.In the southern and southeastern of Brazil, the excessive rainfall during the maturation period negatively affects the quality of red wines. On the other hand, these regions have great potential for the development of sparklings since that for the elaboration of this drink, the grape is harvested before complete its maturation. In the state of Minas Gerais, the conditions of rainy summer season are present in all

  15. Raleio de cachos em vinhedos de altitude e qualidade do vinho da cultivar Syrah Cluster thinning in high altitude vineyards and wine quality from the cultivar Syrah

    Directory of Open Access Journals (Sweden)

    Leonardo Cury da Silva

    2009-02-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito de diferentes intensidades de raleio de cachos de uvas (Vitis vinifera L., em vinhedos de altitude, sobre a evolução dos compostos fenólicos durante a maturação da uva. O experimento foi conduzido em São Joaquim, SC, a uma altitude média de 1.230 m, em videiras da cv.Syrah, enxertadas sobre 'Paulsen 1103', conduzidas em espaldeira, em duplo cordão esporonado, espaçadas em 3x1,2 m, com cobertura antigranizo. Os tratamentos de raleio foram definidos de modo a se ter redução da produtividade em 13,3, 26,6 e 40% em relação à produtividade do tratamento controle sem raleio, estimada em 15 Mg ha-1. Os tratamentos foram ajustados quando 50% das bagas encontravam-se em "véraison". Odelineamento foi o de blocos ao acaso, com quatro repetições e 40 plantas por tratamento. As avaliações foram feitas nas safras 2005/2006 e 2006/2007. Avaliou-se a evolução dos compostos fenólicos durante as oito semanas antecedentes à colheita. O raleio de cachos aumentou o conteúdo de antocianinas quando a produtividade estimada foi de 12 Mg ha-1, e melhorou a composição fenólica das bagas, atributos esses favoráveis à produção de vinhos tintos finos de qualidade.The objective of this work was to evaluate the effect of different intensities of cluster thinning in mountain vineyards cv.Syrah on the evolution of phenolic compounds, during grape maturation. The experiment was carried out in the 2005/2006 and 2006/2007 crop seasons, at São Joaquim, SC, Brazil, at an average altitude of 1,230 m, on 'Syrah' grapevines that had been grafted on 'Paulsen 1103' root stock and trained out in vertical trellis system, spaced in 3x1.2 m and protected against hail. The cluster thinning was adjusted in the "veraison" corresponded to 15 Mg ha-1 (control, 13 Mg ha-1, 11 Mg ha-1 and 9 Mg ha-1, in a complete randomized blocks. The evolution of phenolic compounds was evaluated during the eight antecedent weeks to the

  16. An innovative pot system for monitoring the effects of water stress on grapevines and grape quality

    Science.gov (United States)

    Puccioni, Sergio; Leprini, Marco; Mocali, Stefano; Perria, Rita; Priori, Simone; Storchi, Paolo; Zombardo, Alessandra; Costantini, Edoardo

    2016-04-01

    The advantage of a pot system is the possibility to control many variables and factors with a large number of replicates, obtaining statistically significant results in only one year of experimentation. An innovative pot system for the monitoring of grapevine water stress was set up. The system consists of 99 pots of 70 liters, filled by 3 different soils collected from premium vineyards of the Chianti Classico district (Tuscany). The soils showed different texture (clay-loam, loam and sandy-loam), different gravel and carbonate content, and different available water capacity (AWC). The same soils had been field monitored for grapevine water stress; therefore it was possible to compare the grapevine behaviour both in pot and in field conditions. The grapevine cultivar was Pinot noir clone ENTAV 115, which can be used to investigate the genetic expression in response to environmental factors, since its genome has been sequenced. Different rootstocks theses were compared: not grafted, 1103 Paulsen and M101-14. Each combination rootstock-soil was repeated 9 times. Every pot was equipped for drip irrigation and with electrodes for soil moisture determination by TDR. A non-stop automated control unit recorded meteorological data (temperature and rainfalls), soil temperature and water potential on 9 selected pots. These 9 selected pots were also used to calibrate a model for soil water volume/tension curve. Soil, leaves and grapes samples from each pot were collected for microbial community determination, through NGS analysis. A preliminary study was based on testing the ability of the system to simulate the natural growing conditions of the grapevines. Therefore the grape performances of the potted plants were compared to those of plants cultivated in the vineyards where the soils were taken. In July 2015 three levels of water supply were tested during 5 weeks (up to veraison) in order to study the effects of water stress on the plants and the grape. Later, all the pots

  17. Condições meteorológicas e tipo de solo na composição da uva 'Cabernet Sauvignon'

    Directory of Open Access Journals (Sweden)

    Rodrigo Vieira Luciano

    2013-01-01

    Full Text Available O objetivo deste trabalho foi avaliar os efeitos das condições meteorológicas e do tipo de solo sobre características físico-químicas e compostos fenólicos da uva 'Cabernet Sauvignon' (Vitis vinifera. O experimento foi realizado em vinhedo implantado em 2003, enxertado sobre o porta-enxerto 'Paulsen 1103' e conduzido no sistema espaldeira. No vinhedo, foram selecionados dois solos: Cambissolo Háplico e Cambissolo Húmico. O efeito das condições meteorológicas (precipitação e temperatura mínima e máxima do ar foi avaliado nas safras 2008/2009, 2009/2010 e 2010/2011. Foram determinados os atributos físicos e químicos dos solos, os teores de sólidos solúveis, a acidez titulável e o pH do mosto, bem como o índice de polifenóis totais e dos teores de antocianinas e de taninos da uva. Os fatores solo e as condições meteorológicas (safras foram arranjados em esquema fatorial 2x3. Com exceção do teor de polifenóis totais, as condições meteorológicas e o tipo de solo afetam as características físico-químicas da uva 'Cabernet Sauvignon', com efeito mais pronunciado das condições meteorológicas do que do tipo de solo. Menores precipitações e maiores amplitudes térmicas favorecem o acúmulo de sólidos solúveis na uva 'Cabernet Sauvignon'. Maiores precipitações favorecem o aumento da acidez do mosto.

  18. Den norske EPOC-satellitten: støtte til kunnskapsbaserte beslutninger

    Directory of Open Access Journals (Sweden)

    Susan Munabi-Babigumira

    2013-11-01

    Full Text Available Systematiske oversikter fra det internasjonale Cochrane-samarbeidet er en viktig kilde til oppsummert kunnskap for beslutningstakere i helsevesenet. Den norske satellitten av Cochrane Effective Practice and Organisation of Care (EPOC Review Group har base i Seksjon for global helse, Nasjonalt kunnskapssenter for helsetjenesten, og fokuserer på tiltak som retter seg mot helsesystemer og helsetjenesten i lav- og mellominntektsland. Den norske EPOC-satellitten gir redaksjonell støtte til forfattere som skriver Cochraneoversikter om effekter av slike tiltak, og bidrar dermed til at systematiske oversikter blir utarbeidet og brukt. Behovet for oppsummert kunnskap, skreddersydd for ulike sammenhenger og ulike sluttbrukere, er stort. Ikke minst gjelder det i lav- og mellominntektsland der ressursene er begrenset, og der gode prioriteringer er spesielt viktig.Munabi-Babigumira S, Johansen M, Paulsen E. The Norwegian EPOC-satellite: Support for evidenceinformed decisions. Nor J Epidemiol 2013; 23 (2: 211-214.ENGLISH SUMMARYSystematic reviews from the Cochrane Collaboration are an important source of summarised evidence for decision makers in health care. The Norwegian satellite of the Cochrane Effective Practice and Organisation of Care (EPOC Review Group has its base at the Global Health Unit in the Norwegian Knowledge Centre for the Health Services, and focuses on interventions targeting health systems and services in lowand middle-income countries. The Norwegian EPOC-satellite provides editorial support to authors who write systematic reviews on the effects of such interventions, and contributes to building the capacity for producing and using systematic reviews. The need for summarised evidence, tailored for various settings and various end users, is large. This is particularly important for low- and middle income countries, where resources are limited and it is important to identify the right priorities.

  19. Could be the future climate change an opportunity for the winegrowers? The case study of Aglianico wine in southern Italy.

    Science.gov (United States)

    Bonfante, Antonello; Basile, Angelo; Dragonetti, Giovanna; De Lorenzi, Francesca; De Mascellis, Roberto; Gambuti, Angelita; Giorio, Pasquale; Guida, Giampiero; Manna, Piero; Minieri, Luciana; Oliva, Marco; Orefice, Nadia; Terribile, Fabio

    2015-04-01

    Water deficit is a limiting factor to yield production and crop adaptation to future climate conditions. This is true for crops addressed mainly for biomass production (e.g. maize, wheat, etc.) but not for those where the quality is relevant. Specifically, in grapevine water stress (mid or limited) - occurring during specific phenological phases - is a factor to produce good quality wines. It induces for example the production of anthocyanins and aroma precursors. Therefore, the water stress, due to the future increase of temperature and the rainfall decrease, could represent an opportunity to increase winegrowers' incomes. The study was carried out in Campania region (Southern Italy), in an area vocated to high quality wines production (ZOVISA project: Viticultural zoning at farm scale) The study was realized in two different soils (calcisol and cambisol), under the same climate, on Aglianico cultivar, standard clone population on 1103 Paulsen rootstocks placed along a slope of 90 m length with 11% of gradient. The agro-hydrological model SWAP was calibrated and applied to estimate soil-plant water status at the various crop phenological phases for three vintages (2011-2013). Crop water stress index (CWSI) - estimated by the model - was related to physiological measurements (e.g leaf water potential), grape bunches measurements (e.g. sugar content) and wine quality (e.g. tannins). For both soils, the correlation between measurements and CWSI were high (e.g. -0.97** with sugar; 0.895* with anthocyanins in the skins). Then, the model was applied to future climate condition (2021-2051) obtained from statistical downscaling of GCM in order to estimate the effect of the climate on CWSI and hence on vine quality. The results show that the effects of the climate change on the vine quality is dependent by the soil, being relevant to the cambisol and less pronounced to the calcisol, with an expected improvement of wine quality in the cambisol.

  20. Desempenho vitivinícola da Cabernet Sauvignon sobre diferentes porta-enxertos em região de altitude de Santa Catarina Viticultural performance of cabernet sauvignon grafted on different rootstocks in high altitude regions of Santa Catarina state

    Directory of Open Access Journals (Sweden)

    Alberto Fontanella Brighenti

    2011-03-01

    Full Text Available Apesar de os porta-enxertos serem usados primariamente como uma forma de resistência a pragas, eles são uma ligação entre o solo e a copa, e desempenham um papel importante na adaptação da videira a fatores ambientais. O objetivo deste trabalho foi avaliar três porta-enxertos e dois sistemas de condução na produtividade do vinhedo, no crescimento da copa e nas características físicas dos frutos. O experimento foi conduzido em um vinhedo experimental da Epagri - Estação Experimental de São Joaquim, localizada no município de Painel (28°01'02"S e 50°08'57"O, altitude 1.200 m. O trabalho foi executado com a cultivar Cabernet Sauvignon, enxertada sobre Paulsen 1.103 (Vitis berlandieri x Vitis rupestris, Couderc 3309 (Vitis riparia x Vitis rupestris e 1.014-14 Mgt (Vitis riparia x Vitis rupestris, em dois sistemas de condução, espaldeira e manjedoura, com cinco anos de idade, no espaçamento de 3,0 x 1,5 m. O experimento foi avaliado nas safras de 2007/08 e 2008/09. Os tratamentos porta-enxerto e sistema de condução foram arranjados em um fatorial (3 x 2. O delineamento utilizado foi o de blocos ao acaso, com quatro blocos e 20 plantas por parcela. Foram avaliados a área foliar, a produtividade médias das plantas, o índice de Ravaz, o peso de material podado, o peso de cachos, peso de 50 bagas, o número de bagas por cacho, o diâmetro das bagas, os teores de sólidos solúveis, a acidez total, o pH, os teores de antocianinas, o índice de polifenóis totais e os taninos. Plantas enxertadas em Paulsen 1103 apresentaram as menores produtividades e as maiores áreas foliares. 3.309C é o porta-enxerto menos vigoroso e interfere de maneira positiva na frutificação efetiva, pois produz maior número de bagas por cacho e bagas mais pesadas. Os porta-enxertos 1.103P e 101-14 Mgt, apresentam os melhores resultados para antocianinas.Rootstocks are a link between the soil and the scion, they play an important role in vine adaptation

  1. Performance of painted plywood and cloth Nzi traps relative to Manitoba and greenhead traps for tabanids and stable flies.

    Science.gov (United States)

    Mihok, Steve; Carlson, David A

    2007-04-01

    Experiments were conducted to adapt the cloth Nzi trap to a format suitable for fixed applications in biting fly sampling or control. Catches of tabanids [Tabanus L., Chrysops (Meigen), and Hybomitra Enderlein], and stable flies [Stomoxys calcitrans (L.)] in painted plywood traps were compared with those in standard phthalogen blue cloth traps, and in similarly painted cloth traps. The Manitoba horse fly trap and the Tabanus nigrovittatus Macquart "greenhead" box trap were used as additional standards during one tabanid season. Shiny features of traps reduced catches, e.g., paint on cloth instead of wood, or use of aluminum screening instead of netting. Nevertheless, appropriately painted plywood Nzi traps caught as many biting flies as did standard cloth Nzi traps, if paint finishes were matte, and with the use of phthalogen blue colorants. Nzi traps collected about the same tabanid fauna as the Manitoba and T. nigrovittatus traps, but with improved catches of Chrysops and Tabanus. Recommendations are provided on appropriate color matching, and selection of readily-available materials for trap construction. PMID:17461091

  2. The repellency of lemongrass oil against stable flies, tested using video tracking.

    Science.gov (United States)

    Baldacchino, Frédéric; Tramut, Coline; Salem, Ali; Liénard, Emmanuel; Delétré, Emilie; Franc, Michel; Martin, Thibaud; Duvallet, Gérard; Jay-Robert, Pierre

    2013-01-01

    Lemongrass oil (Cymbopogon citratus) is an effective repellent against mosquitoes (Diptera: Culicidae) and house flies (Diptera: Muscidae). In this study, its effectiveness was assessed on stable flies (Diptera: Muscidae) in laboratory conditions. First, we demonstrated that lemongrass oil is an active substance for antennal olfactory receptor cells of Stomoxys calcitrans as indicated by a significant increase in the electroantennogram responses to increasing doses of lemongrass oil. Feeding-choice tests in a flight cage with stable flies having access to two blood-soaked sanitary pads, one of which was treated with lemongrass oil, showed that stable flies (n = 24) spent significantly more time in the untreated zone (median value = 218.4 s) than in the treated zone (median value = 63.7 s). No stable flies fed on the treated pad, whereas nine fed on the untreated pad. These results suggest that lemongrass oil could be used as an effective repellent against stable flies. Additional studies to confirm its spatial repellent and feeding deterrent effects are warranted. PMID:23759542

  3. Descriptive epidemiology of insects infesting domestic sheep (ovis aries) of district toba tek singh, punjab, pakistan

    International Nuclear Information System (INIS)

    During a cross-sectional prospective epidemiological survey, a total of 2412 sheep were screened for the prevalence of insects. Out of which, 333 (13.80%) were harbored for insects including lice (36.57%), fleas (3.23%) and flies (1.62%). Among the identified species of lice, Haematopinus spp. (44.14%) was predominant followed in order by Damalinia ovis (26.42%) and Linognathus spp. (17.71%). The flea Ctenocepahlides (Ct). felis was more common (4.50%) than Ct. canis (3.30%). Stomoxys calcitrans (3.90%) was the only prevalent specie of fly in the study area. Infestation rate was higher in young sheep (72.68%) as compared to adults (27.32%) and level of infestation was significantly higher in females (75.37%) than males (24.62%). Amongst various breeds of sheep, Cholistani (19.81%) had the highest prevalence followed by Kajli (13.49%), Thalli (12.94%) and Lohi (11.80%). Prevalence of flies (37%) and lice (47%) was highest in December and January, respectively; whereas,that of fleas (39%) reached a peak in April. Among various associated determinants, stall feeding, closed housing, tethered animals and non-cemented floor were found positively associated (P<0.05) with insect infestation. The results showed that insect abundance and the variety of genera were wide in this part of Pakistan. This also causes concern over the emergence of insect-borne diseases in domestic animals. (author)

  4. Reproductive capacity and longevity of stable flies maintained on different kinds of blood.

    Science.gov (United States)

    DuToit, G D

    1975-12-01

    An investigation was made into some lesser known aspects of the biology of the stable fly, Stomoxys calcitrans, in order to find a basis for possible means of natural control of the pest on dairy farms. The reaction of adults to different kinds of blood was tested. Diets investigated were bovine blood alternated with ovine blood, bovine blood alternated with pig's blood, bovine blood alternated with manure filtrate, bovine blood alone, ovine blood alone, pig's blood alone and manure filtrate alone. Adults could not servive on manure filtrate alone. Flies in the other treatments exhibited no marked differences as regards duration of pre-mating-, pre-oviposition- and oviposition periods. There were, however, differences in the number of eggs laid. Females maintained on bovine blood alone produced most eggs i.e. 2,3 times as many as those laid by females fed on pig's blood alone. The latter were the poorest producers. Viability and incubation period of eggs did not appear to be affected by the kind of blood fed to the adults. Flies, however, lived longer when supplied with bovine blood and died sooner when maintained on pig's blood. PMID:1223286

  5. Suppressing immature house and stable flies in outdoor calf hutches with sand, gravel, and sawdust bedding.

    Science.gov (United States)

    Schmidtmann, E T

    1991-11-01

    Sand, gravel, sawdust, and pine shavings were used as bedding in outdoor calf hutches and compared with straw relative to the density of immature (maggot) house flies, Musca domestica, and stable flies, Stomoxys calcitrans. In 6-wk field trials, average densities of house and stable fly maggots in concrete mix sand ranged from only .3 to 1.6 and 0 to .1 maggots/L, respectively; pea size gravel bedding also strongly suppressed densities from less than .1 to .3 and less than .1 to .1 maggots/L, respectively. These densities represent reductions of 76 to greater than 99% relative to straw bedding, but both sand and gravel compacted and became soiled with calf feces, which resulted in unacceptable bedding sanitation and foul odors. Densities of house and stable fly maggots in pine shavings did not differ from those in straw bedding. Nevertheless, in sawdust bedding, maggot density was limited to averages of 1.4 to 8.3 house and 9.8 to 11.8 stable fly maggots/L; this represented reductions of 45 to 91% relative to straw. In a follow-up trial, house and stable fly maggot densities in sawdust averaged 11.3 and 43.9 maggots/L, respectively, reductions of 77 and 46%. These findings suggest that bedding calf hutches with sawdust during warm weather can be useful as an ecologically sound approach to controlling muscoid fly populations on dairy farms. PMID:1757634

  6. Use of radioisotopes to elucidate the role of regurgitation for direct transfer of parasites or disease agents between host organisms through arthropod vectors

    International Nuclear Information System (INIS)

    In the context of the transmission of parasites and disease agents by bloodfeeding arthropods, the hitherto neglected phenomenon of regurgitation is of the greatest importance. It makes possible the direct transfer of ingested blood, together with these disease agents, within the shortest period of time after intake without the interaction of any circulative or transformative processes in the vector. Owing to such direct transmission from host to host, the epidemiology of vector borne diseases (e.g. arbo-viruses or certain protozoan diseases such as trypanosomiasis, leishmaniosis or even malaria) is influenced by additional factors. Regurgitative transmission should be considered in programmes of eradication and procedures of quarantine or isolation. We have examined the occurrence of regurgitation in a systematic way with the use of tracer techniques, in combination with other methods. The main arthropods are ticks (especially Ornithodoros moubata Murray), bloodsucking Hemiptera (e.g. Triatoma phyllosoma Burmeister), bloodsucking Muscidae (mainly Stomoxys calcitrans L.) and also mosquitoes. As can be shown with aphid, in which THO was used as a tracer, immediate transmission occurs in stable flies and soft ticks after labelling with 32P and 14C, and it can even be quantified. Also, the output of saliva secreted into and collected from the crop must be regarded as regurgitation rather than salivation. Since it can mix with previously ingested food (blood plus disease agents), this type of regurgitation can also contribute to the transmission of diseases by arthropods. (author). 23 refs, 3 figs, 2 tabs

  7. Use of isotopes as model substances to elucidate the mode of transmission of pathogens to animals and plants by arthropod vectors

    International Nuclear Information System (INIS)

    Experimental work was begun with J.F. Butler and L.A. DuBose on the biting flies Stomoxys calcitrans (L.) and Haematobia irritans (L.), which are important ectoparasites of livestock. Several possible mechanisms for the transmission of pathogenic materials to animals were defined, using radioisotopes: (1) mechanical transmission from contaminated mouthparts; (2) transfer through regurgitation; (3) transfer via saliva; (4) transfer through the alimentary tract. A generalized scheme was developed for the paths of uptake and excretion of radioisotopes through the organism of insects. First, experiments applied this model to blood-feeding arthropods such as the stable fly and hornfly, tsetse flies, sheep keds (Melophagus ovinus L.), mosquitoes (Culex sp., Aedes sp.), Triatoma infestans Klug (Hemiptera, Triatomidae), and the tick Ornithodorus moubata Murray. Very similar principles and possibilities for the transfer of pathogens also appear to apply to plant-sucking aphids (vectors of virus diseases in plants) as to blood-feeding arthropods. Regurgitation found in biting flies, appears in ticks as well as in Triatomidae and tsetse flies (in the last two only under stress conditions) and could even be observed in aphids. Thus, aphids and certain biting arthropods can immediately transfer pathogens after feeding on an infected host plant or animal, on migrating to another host, findings mainly possible through using radioisotopes. The results on aphids include discussion of the ingestion-egestion hypothesis of noncirculative virus transmission, described by Harris in 1977

  8. House and Stable Fly Seasonal Abundance, Larval Development Substrates, and Natural Parasitism on Small Equine Farms in Florida.

    Science.gov (United States)

    Machtinger, E T; Leppla, N C; Hogsette, J A

    2016-08-01

    House flies, Musca domestica Linnaeus, and stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae), are common pests on horse farms. The successful use of pupal parasitoids for management of these pests requires knowledge of seasonal fluctuations and biology of the flies as well as natural parasitism levels. However, these dynamics have not been investigated on small equine farms. A 1-year field study began in July 2010, in north central Florida, to determine adult fly population levels and breeding areas on four small equine farms. Weekly surveillance showed that pest flies were present year-round, though there were differences in adult population levels among farms and seasons. Fly development was not confirmed on two of the four small farms, suggesting that subtle differences in husbandry may adversely affect the development of immature flies. In six substrates previously identified as the most common among the farms, stable fly puparia were found overwhelmingly in hay mixed with equine manure and house fly puparia were found in fresh pine shavings mixed with equine manure. Natural parasitism was minimal as expected, but greatest numbers of natural parasitoids collected were of the genus Spalangia. Differences in adult and immature fly numbers recovered emphasizes the need for farm owners to confirm on-site fly development prior to purchase and release of biological control agents. Additionally, due to the low natural parasitism levels and domination of parasitism by Spalangia cameroni, augmentative releases using this species may be the most effective. PMID:26902468

  9. Repellency of a wax-based catnip-oil formulation against stable flies.

    Science.gov (United States)

    Zhu, Junwei J; Dunlap, Christopher A; Behle, Robert W; Berkebile, Dennis R; Wienhold, Brian

    2010-12-01

    Stable flies, Stomoxys calcitrans (L.), are one of the most serious livestock pests, which cause significant economic loss in the cattle industry. Current practices for managing stable flies are limited to costly sanitation techniques and unsustainable insecticide applications. The present study reports the initial efforts using catnip essential oil as a spatial repellent and the results of field trials using a wax-based formulation to repel stable flies in the cattle feedlot. Electroantennograms showed that catnip oil and its ingredient compounds elicit significant antennal responses from both sexes of stable flies. Catnip oil and ZE- and EZ-nepetalactone showed repellent activity in a single cage olfactormeter study. No behavioral activity was observed from another ingredient compound, caryophyllene. A laboratory dispersal bioassay also showed that stable flies avoided areas treated with catnip oil. Using a solid phase microextraction (SPME) method, the atmospheric concentration of catnip active ingredient compounds (nepetalactones) absorbed by SPME fiber in treated areas was detected at 4 times higher than those in control areas. Application of wax-based catnip pellets in cattle feedlots resulted in >99% repellency of stable flies in treated areas, compared with that in nontreated areas. However, the repellent efficacy of the formulation only lasted 3 h. This is the first study demonstrating the potential application of a plant-based repellent formulation that may be used as an alternative method against stable flies. PMID:21058736

  10. Reassessment of the potential economic impact of cattle parasites in Brazil.

    Science.gov (United States)

    Grisi, Laerte; Leite, Romário Cerqueira; Martins, João Ricardo de Souza; Barros, Antonio Thadeu Medeiros de; Andreotti, Renato; Cançado, Paulo Henrique Duarte; León, Adalberto Angel Pérez de; Pereira, Jairo Barros; Villela, Humberto Silva

    2014-01-01

    The profitability of livestock activities can be diminished significantly by the effects of parasites. Economic losses caused by cattle parasites in Brazil were estimated on an annual basis, considering the total number of animals at risk and the potential detrimental effects of parasitism on cattle productivity. Estimates in U.S. dollars (USD) were based on reported yield losses among untreated animals and reflected some of the effects of parasitic diseases. Relevant parasites that affect cattle productivity in Brazil, and their economic impact in USD billions include: gastrointestinal nematodes - $7.11; cattle tick (Rhipicephalus (Boophilus) microplus) - $3.24; horn fly (Haematobia irritans) - $2.56; cattle grub (Dermatobia hominis) - $0.38; New World screwworm fly (Cochliomyia hominivorax) - $0.34; and stable fly (Stomoxys calcitrans) - $0.34. The combined annual economic loss due to internal and external parasites of cattle in Brazil considered here was estimated to be at least USD 13.96 billion. These findings are discussed in the context of methodologies and research that are required in order to improve the accuracy of these economic impact assessments. This information needs to be taken into consideration when developing sustainable policies for mitigating the impact of parasitism on the profitability of Brazilian cattle producers. PMID:25054492

  11. Detection of West Nile virus in stable flies (Diptera: Muscidae) parasitizing juvenile American white pelicans.

    Science.gov (United States)

    Johnson, Gregory; Panella, Nicholas; Hale, Kristina; Komar, Nicholas

    2010-11-01

    Stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae), an economically important pest of livestock and humans, were observed parasitizing prefledged American white pelicans, Pelecanus erythrorhynchos (Pelecaniformes: Pelecanidae), in a pelican breeding colony in northeastern Montana where die-offs attributed to West Nile virus (family Flaviviridae, genus Flavivirus, WNV) have occurred since 2002. Engorged and unengorged flies were collected off nine moribund chicks. Of 29 blood-engorged flies testing positive for vertebrate DNA, all 29 contained pelican DNA. Virus isolation was performed on 60 pools (1,176 flies) of unengorged flies using Vero cell plaque assay. Eighteen pools were positive for WNV for an estimated infection rate of 18.0 per 1,000 flies. Fifty-four percent (36/67) of abdomens from blood-engorged flies tested positive for WNV. Pelican viremia levels from the blood-engorged fly abdomens revealed that at least one of the ill pelicans circulated a viremia capable of infecting Culex mosquito vectors. Stable flies may be involved in WNV transmission within the pelican breeding colony by serving as either a mechanical vector or as a source for oral infection if ingested by predators. PMID:21175073

  12. Diatom thanatocoenosis in a middle Galician Ría: Spatial patterns and their relationship to the seasonal diatom cycle in the water column and hydrographic conditions

    Science.gov (United States)

    Bernárdez, Patricia; Prego, Ricardo; Varela, Manuel; Francés, Guillermo

    2008-10-01

    Modern diatom distribution patterns in the surface sediment of the Ferrol Ría and their relationship to the hydrography and diatom patterns in the water column were studied to determine the hydrographic influence on the record of these biogenic components. Diatom abundance in the water column was assessed for different oceanographic periods and compared with the biosiliceous sedimentary record. Very low abundances were found in the water column during the winter, whereas in spring and summer, diatoms proliferated. Chaetoceros spp. formed the bulk of the water column community during spring and summer, followed by Thalassionema nitzschioides and Rhizosolenia spp. Nitzschia longissima represented a significant portion of the winter assemblage, together with Paralia sulcata and benthic taxa . Leptocylindrus danicus, N. longissima and Skeletonema costatum characterized the autumn campaign, when stratification of the waters occurs, with L. danicus being especially abundant in the outer ría. Seasonal hydrographic and associated productivity patterns govern the abundance and assemblage of the diatoms preserved in surface sediments. Samples located in the inner ría area and its margins exhibited the highest abundances of diatoms, and were primarily dominated by benthic species. The freshwater group, crysophycean cysts and phytoliths were present in the landward stations influenced by river runoff. The middle ría was characterized by P. sulcata and Thalassiosira spp., with minor occurrences of the benthic and freshwater group. Chaetoceros R.S., L. danicus R.S. and T. nitzschioides typified the outer ría, an assemblage that corresponds to nutrient-rich coastal areas of high productivity influenced by oceanic waters, demonstrating the impact of oceanic waters flowing into the embayment due to enhanced tidal mixing through the narrow channel. Therefore, sediment diatom assemblages reflect diatom production patterns in the water column of the Ría. However, we must proceed

  13. O microfitoplâncton das águas costeiras do litoral Fluminense (estado do Rio de Janeiro: lista de especies e aspectos ecológicos Microphytoplankton from coastal waters of Rio de Janeiro: species composition and ecological aspects

    Directory of Open Access Journals (Sweden)

    Nadja M. Lins da Silva

    1988-01-01

    Full Text Available O microfitoplâncton das águas costeiras entre Cabo Frio e Rio de Janeiro foi coletado durante as operações PLATAFORMA IV, V e VI do AvPqOc SO OLIVEIRA (DGN nos meses de outubro de 1984 e janeiro e março de 1985, As variações qualitativas e quantitativas foram analisadas em função das condições hidrológicas por meio de um tratamento estatístico multivariado dos dados. O fenômeno de ressurgência, responsável seja pelo afloramento da Água Central do Atlântico Sul, seja pela formação de uma termo-clina na camada eufótica, é o fator de terminante do crescimento algal que começa com especies de pequeno porte (Skeletonema costatum, Nitzschia spp e evolui para uma maior diversidade com especies dos gêneros Guinardia, Rhizosolenia, Chaetoceros, Thalassiothrix. Em condição de estratificação da coluna d'agua notou-se a influência das aguas da Baía de Guanabara, com forte crescimento de Skeletonema costatum, e uma grande quantidade de detritos associados a algas cianofíceas e formas nanoplanctônicas.Phytoplankton of the coastal water between Cabo Frio and Rio de Janeiro were studied at the upwelling season (October, January and Maroh. Qualitative and quantitative variations are analized in function of the hydrological conditions by means of a multivariate statistical treatment of data. Cabo Frio upwelling is responsible for occurrence of a thermocline in the euphotic layer which induces phytoplankton growth, beginning by small-sized species (Nitzschia spp, Skeletonema costatum and evoluting to highest diversity and quantity of different microphytoplanktonic forms (Guinardia, Rhizosolenia, Chaetoceros, Thalassiothrix. When water column is sharply stratified, we observe Guanabara Bay influence, with high growth of Skeletonema costatum and high quantity of detritus together with blue-green algae and nanoplanktonic forms.

  14. Effects of simulated benthic fluxes on phytoplankton dynamic and photosynthetic parameters in a mesocosm experiment (Bay of Brest, France)

    Science.gov (United States)

    Claquin, Pascal; NÍ Longphuirt, Sorcha; Fouillaron, Pierre; Huonnic, Pierre; Ragueneau, Olivier; Klein, Cécile; Leynaert, Aude

    2010-01-01

    Benthic faunal activity and density play an important role in determining the rates of benthic nutrient fluxes, which enrich the water column and contribute to phytoplankton growth. The intensity of nutrient fluxes in the Bay of Brest depends on the density of the invasive gastropod, Crepidula fornicata. In order to study the impact of benthic fluxes on phytoplankton dynamics, realistic daily nutrient inputs simulating various densities of C. fornicata were added to six enclosures during three weeks. The increase in fertilization intensity influenced the phytoplankton biomass. A succession from Chaetoceros spp. to Pseudo-nitzschia spp. and Leptocylindrus danicus was observed in all enclosures, but the dynamics of successions were different. Pseudo-nitzschia spp. was favored in the three more fertilized enclosures, while Chaetoceros spp. persisted longer in less enriched enclosures. Despite an apparent nitrogen limitation, the quantum efficiency of PSII (F v/F m) was high (>0.5) and stable in all enclosures. The maximal photosynthetic capacity (P Bmax) was also invariable and oscillated around an average value of 2.23 mg C (mg Chl a) -1 h -1. The stability of F v/F m and P Bmax observed at different nutrient input intensities demonstrates that the daily inputs maintained the physiological balance of the microalgae. The maximal light utilization efficiency (α) and the light saturation parameter (E k) were also quite stable after day 8, which reveals that photosynthetic parameters were driven by growth constraints due to nutrient availability and not by incident light or species successions. We suggest that our results correspond to an "E k independent variation" regulation. We propose that such regulation of photosynthetic parameters appears when there are frequent nutrient additions which do not allow replete nutrient conditions to be reached but lead to physiological equilibrium. Thanks to our results we can understand how even low benthic fluxes, by supporting

  15. A preliminary study on phytoplankton community of Yantai Taozi Bay in autumn%烟台套子湾海域秋季浮游植物群落的初步研究

    Institute of Scientific and Technical Information of China (English)

    宁璇璇; 纪灵; 王刚; 夏炳训; 丁琳

    2011-01-01

    根据2010年11月的调查数据,对套子湾海域浮游植物的群落结构进行了初步研究.共鉴定浮游植物3门24属43种,主要为温带近岸性和广布性种.其中,硅藻门20属35种,占总种数的81.40%,以圆筛藻属(Coscinodiscus)和角毛藻属(Chaetoceros)的种类为主;甲藻类3属7种,占总种数的16.28%,由角藻属(Ceratium)、多甲藻属(Peridinium)及夜光藻(Noctiluca scintillans)组成;金藻门只有小等刺硅鞭藻(Dictyocha fibula)1种.浮游植物细胞丰度的平面分布主要由浮游硅藻的分布决定,其高值区位于套子湾北部湾口和西北部区域.多样性分析表明,该海域浮游植物群落结构比较稳定.聚类分析发现浮游植物基本可归为4大类群,不同群落类型间的组成呈显著性差异.%Features of phytoplankton community were studied, based on the survey data of Taozi Bay in autumn, 2010. The results showed that 43 phytoplankton species were identified altogether, belonging to 3 phyla with 24 genera, in which 81.40% were Bacillariophyta and 16.28% were Dinophyta. In Bacillariophyta, Coscinodiscus and Chaetoceros were the dominant groups in terms of species number while Dinophyta was composed of Ceratium, Peridinium and Noctiluca scintillans. In Chrysophta, only Dictyocha fibula was identified. The horizontal distribution of phytoplankton was mainly determined by the diatom distribution pattern. It was high in the north and northwest of Taozi Bay. Analysis of Shannon-Wiener index, Margalef index and Pielou index showed the community structure was stable. The species at 14 stations were grouped into four ecotypes with cluster analysis, and One-Way ANOSIM test of four cruises revealed significant differences in both global and for pairwise test.

  16. Fitoplancton del Parque Nacional Las Tablas de Daimiel. III. Diatomeas y clorofitas

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    Rojo, Carmen

    2000-06-01

    Full Text Available Las Tablas de Daimiel National Park is an important semi-arid wetland, biodiversity reserve, that is experiencing an accelerated eutrophication process and dramatic hydrological changes in recent years. This paper reports the taxonomy, dynamics and ecology of 9 planktonic diatoms (2 centric, 7 pennate and 37 chlorophytes (24 coccoids. 8 flageflated and 5 species of other groups which were found from 1996 to 1998. Despite the higher diversity of Chlorococcales, diatoms made a major contribution to algal biomass. Most species are typical of eutrophic systems and some are salinity indicators (Chaetoceros muelleri. Scenedesmus quadricauda, Cyclotella meneghiniana and Nitzschia acicularis were the most common species. Pteromonas limnetica is a new record for Spain. There was a remarkable decrease in phytoplankton density and a 50 % species substitution in comparison to the drier period 1992-1993. Species distribution through the wetland was very heterogeneous spatially and temporally, without any pattern.El Parque Nacional Las Tablas de Daimiel es un humedal semiárido, importante como reserva de biodiversidad, que sufre un acelerado proceso de eutrofización y profundos cambios hidrológicos. En este trabajo se describen la taxonomía, la dinámica y la ecología de las 9 diatomeas (2 centrales, 7 pennadas y las 37 clorofitas (24 cocales, 8 flageladas y 5 especies de otros grupos recolectadas entre los años 1996-1998. La mayor parte de las especies son características de ambientes eutróñcos y algunas son indicadoras de salinidad (Chaetoceros muelleri. Las especies más abundantes fueron Scenedesmus quadricauda, Cyclotella meneghiniana y Nitzschia acicularis. Pteromonas limnetica es primera cita española. Con respecto al período de sequía de 1992-1993, se constata una considerable disminución en la densidad fitoplanctónica y una sustitución de especies del 50 %• Se observó una gran heterogeneidad espaciotemporal en la distribuci

  17. Pigment signatures of some diatoms isolated from China seas

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The photosynthetic pigments of 12 species (14 strains) of cultured diatoms from six genera under specific conditions were examined by the HPLC. The diatom genera were Skeletonema, Thalassiosira, Chaetoceros, Nitzschia, Phaeodactylum and Meuniera. All strains were isolated from China seas and most of them were from the Jiaozhou Bay, China. Fifteen pigments were identified and eight of them were various chlorophyll a derivatives. Chlorophyll a, c2 and c1 and the carotenoids fucoxanthin, diadinoxanthin, diatoxanthin and β,β-carotene existed in all species. The ratios of each pigment to chlorophyll a were compared with the results in literatures. The pigment ratios of this study generally fall within the ranges reported by the literatures although the maximum ratio of fucoxanthin to chlorophyll a was higher and the ratios of chlorophyll c and diatoxanthin to chlorophyll a were low. The pigment ratios are useful to understanding the pigment signatures of diatoms in the Jiaozhou Bay, China, and to setting up the chemotaxonomic method ofphytoplankton in these sea areas.

  18. Growth of microalgae in autotrophic stationary systems

    Directory of Open Access Journals (Sweden)

    Paulo Cunha

    2008-06-01

    Full Text Available In this paper we evaluate the growth of nine marine microalgae species (Nannochloropsis oculata, Thalassiosira pseudonana, Phaeodactylum tricornutum, Isochrysis galbana, Tetraselmis suecica, Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira fluviatilis and Isochrysis sp. and one freshwater species (Chlorella vulgaris under stationary autotrophy conditions, using erlenmeyers fl asks with 800mL of culture medium exposed to constant light intensities providing a photon flux density of about 150μmol.m-2.s-1 and 25±2oC temperature and constant air flow. The experiment was carried out in a controlled environment considering a block delineating randomized over time with three replicates. The Nannochloropsis oculata showed the highest value of maximum cellular density, but with a longer period of time and a lower growth rate. This was probably due to its tiny cell size, demanding a large number of cells per volume to attain its optimum conditions for light, nutrients, water and atmospheric carbon dioxide. In addition, in spite of showing one of the lowest values of maximum cellular density, Thalassiosira fluviatilis was the species that reached its maximum in a short period of time at the highest growth rate. Chlorella vulgaris was the only freshwater species tested and it showed the poorest performance for all the variables analyzed in the current study.

  19. Paradoxical effects of temperature and solar irradiance on the photodegradation state of killed phytoplankton.

    Science.gov (United States)

    Amiraux, Rémi; Jeanthon, Christian; Vaultier, Frédéric; Rontani, Jean-François

    2016-06-01

    The aim of this paper was to study the effects of temperature and irradiance on the photodegradation state of killed phytoplankton cells. For this purpose, killed cells of the diatom Chaetoceros neogracilis RCC2022 were irradiated (photosynthetically active radiation) at 36 and 446 J · s(-1)  · m(-2) (for the same cumulative dose of irradiation energy) and at two temperatures (7°C and 17°C). Analyses of specific lipid tracers (fatty acids and sterols) revealed that low temperatures and irradiances increased photooxidative damages of monounsaturated lipids (i.e., palmitoleic acid, cholesterol and campesterol). The high efficiency of type II photosensitized degradation processes was attributed to: (i) the relative preservation of the sensitizer (chlorophyll) at low irradiances allowing a longer production of singlet oxygen and (ii) the slow diffusion rate of singlet oxygen through membranes at low temperatures inducing more damages. Conversely, high temperatures and irradiances induced (i) a rapid degradation of the photosensitizer and a loss of singlet oxygen by diffusion outside the membranes (limiting type II photosensitized oxidation), and (ii) intense autoxidation processes degrading unsaturated cell lipids and oxidation products used as photodegradation tracers. Our results may explain the paradoxical relationship observed in situ between latitude and photodegradation state of phytoplankton cells. PMID:26992328

  20. A biological source of oceanic alkyl nitrates

    Science.gov (United States)

    Dahl, E. E.; Lewis, C. B.; Velasco, F. L.; Escobar, C.; Kellogg, D.; Velcamp, M.

    2013-12-01

    Alkyl nitrates are an important component of reactive nitrogen in the troposphere. The oceans are a source of alkyl nitrates to the atmosphere, however the source of alkyl nitrates in the oceans is unknown. It has been demonstrated that the reaction of alkyl peroxy radicals (ROO) with nitric oxide (NO) produces alkyl nitrates in the aqueous phase. We hypothesize that alkyl nitrates may be formed by organisms through the same reaction and therefore biological production could be a source of alkyl nitrates to the troposphere. This work focuses on the production of alkyl nitrates by the diatoms Chaetoceros muelleri and Thalassiosira weisfloggi. Using chemostats, we measure alkyl nitrates formed under nitrate limited conditions. We also use triggers and inhibitors of nitric oxide formation to determine if alkyl nitrate formation is affected by changes in NO production. To date, the rates of production of alkyl nitrates in our cultures, lead us to estimate a production rate on the order of femtomolar/day for C1-C3 alkyl nitrates by diatom species in the equatorial Pacific Ocean. This suggests that diatoms may contribute to the overall ocean source of alkyl nitrates; however, it is possible that other types of phytoplankton, such as cyanobacteria, that are more abundant in the open ocean, may contribute to a greater extent.

  1. Bioavailability of riverine dissolved organic matter to phytoplankton in the marine coastal waters

    Science.gov (United States)

    Jurgensone, Iveta; Aigars, Juris

    2012-07-01

    Nutrient inputs from catchments with intensive agriculture are mostly dominated by inorganic nutrients, whereas the contribution of organic nutrients from catchments with natural forests can be considerable but there is a pooere understanding of this nutrient source. Consequently this study investigated spring, summer and autumn phytoplankton community responses to enrichment by riverine dissolved organic matter (DOM). Dissolved organic substances were extracted from the Daugava River, fractionated into three molecular size classes: 1) 5-100 kDa, 2) 100-1000 kDa, and 3) >1000 kDa, and added to a microcosm with natural assemblages from the Gulf of Riga. During the spring the phytoplankton community was dominated (97%) by diatoms and the species composition did not change over the course of the experiment. Specific species and functional groups of the summer and autumn phytoplankton communities responded positively to these treatments. Small-celled cyanobacteria and Monoraphidium contortum responded to almost all size fractions of DOM for the summer and autumn experiments. Oocystis spp. characteristic for the summer and Chaetoceros wighamii, Cyclotella spp., Thalassiosira baltica for the autumn responded to treatment by two and three size classes of organic substances, respectively, while Merismopedia spp. shifted from one food source to another during the summer experiment.

  2. MF/UF rejection and fouling potential of algal organic matter from bloom-forming marine and freshwater algae

    KAUST Repository

    Villacorte, Loreen O.

    2015-07-01

    Pretreatment with microfiltration (MF) or ultrafiltration (UF) membranes has been proposed for seawater reverse osmosis (SWRO) plants to address operational issues associated with algal blooms. Here, we investigated the MF/UF rejection and fouling potential of algal organic matter (AOM) released by common species of bloom-forming marine (Alexandrium tamarense and Chaetoceros affinis) and freshwater (Microcystis sp.) algae. Batch culture monitoring of the three algal species illustrated varying growth pattern, cell concentration, AOM released and membrane fouling potential. The high membrane fouling potential of the cultures can be directly associated (R2>0.85) with AOM such as transparent exopolymer particle (TEP) while no apparent relationship with algal cell concentration was observed. The AOM comprised mainly biopolymers (e.g., polysaccharides and proteins) and low molecular weight organic compounds (e.g., humic-like substances). The former were largely rejected by MF/UF membranes while the latter were poorly rejected. MF (0.4μm and 0.1μm pore size) rejected 14%-56% of biopolymers while conventional UF (100kDa) and tight UF (10kDa) rejected up to 83% and 97%, respectively. The retention of AOM resulted in a rapid increase in trans-membrane pressure (δP) over time, characterised by pore blocking followed by cake filtration with enhanced compression as illustrated by an exponential progression of δP. © 2015 Elsevier B.V.

  3. Impacta of CO2 enrichment on growth and photosynthesis in freshwater and marine diatoms

    Institute of Scientific and Technical Information of China (English)

    HU Hanhua; GAO Kunshan

    2008-01-01

    The physiological responses of Nitzschia palea Kiitzing, a freshwater diatom, to elevated CO2 were investigated and compared with those of a marine diatom, Chaetoceros muelleri Lemmermann previously reported. Elevated CO2 concentration to 700 μl/L increased the dissolved inorganic carbon (DIC) and lowered the pH in the cultures of N. palea, thus enhancing the growth by 4%-20% during the whole growth period. High CO2-grown N. palea cells showed lower levels of dark respiration rates and higher Ik values. Light-saturated photosynthetic rates and photosynthetic efficiencies decreased in N. palea with the doubling CO2 concentration in airflow to the bottom of cultures, although the doubling CO2 concentration in airflow to the surface cultures had few effects on these two photosynthetic parameters. N. palea cells were found to be capable of using HCO3- in addition to gaseous CO2, and the CO2 enrichment decreased their affinity for HCO3- and CO2. Although doubled CO2 level would enhance the biomass of N. palea and C. muelleri to different extents, compared with the marine diatom, it had a significant effect on the specific growth rates of N. palea. In addition, the responses of photosynthetic parameters of N. palea to doubled CO2 concentration were almost opposite to those of C. muelleri.

  4. Headspace solid-phase microextraction with on-fiber derivatization for the determination of aldehydes in algae by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Ma, Jiping; Xiao, Ronghui; Li, Jinhua; Li, Jie; Shi, Benzhang; Liang, Yanjuan; Lu, Wenhui; Chen, Lingxin

    2011-06-01

    A simple, fast, sensitive and cost-effective method based on headspace solid-phase microextraction (HS-SPME) with on-fiber derivatization coupled with gas chromatography-mass spectrometry was developed for the determination of six typical aldehydes, 2E-hexenal, heptanal, 2E-heptenal, 2E,4E-heptadienal, 2E-decenal and 2E,4E-decadienal in laboratory algae cultures. As derivatization reagent, O-2,3,4,5,6-(pentafluorobenzyl) hydroxylamine hydrochloride, was loaded onto the poly(dimethylsiloxane)/divinylbenzene fiber for aldehydes on-fiber derivatization prior to HS-SPME. Various influence factors of extraction efficiency were systematically investigated. Under optimized extraction conditions, excellent method performances for all the six aldehydes were attained, such as satisfactory extraction recoveries ranging from 67.1 to 117%, with the precision (relative standard deviation) within 5.3-11.1%, and low detection limits in the range of 0.026-0.044 μg/L. The validated method was successfully applied for the analysis of the aldehydes in two diatoms (Skeletonema costatum and Chaetoceros muelleri), two pyrrophytas (Prorocentrum micans and Scrippsiella trochoidea) and Calanus sinicus eggs (feeding on the two diatoms above). PMID:21567947

  5. 2007年春夏季锦州湾浮游植物群落结构特征%Community structure of phytoplankton in Jinzhou Bay in spring and summer 2007

    Institute of Scientific and Technical Information of China (English)

    杨世民; 李岿然; 白洁

    2010-01-01

    研究了2007年春季和夏季辽宁省锦州湾16个大面站网采浮游植物的群落结构特征.共检出浮游植物4门38属59种,在两个季节的调查中硅藻在物种数量和细胞丰度上占绝对优势.春季平均细胞丰度为5.44×104/m3,主要优势种为中肋骨条藻Skeletonema costatum和具槽帕拉藻Paralia sulcata;夏季平均细胞丰度为9.73×104/m3,主要优势种为扭链角毛藻Chaetoceros tortissimus和劳氏角毛藻C.lorenzianus.锦州湾春季细胞丰度高值区位于湾西部和东南部;夏季细胞丰度则呈现西高东低的分布趋势.两季节浮游植物的Shannon-Wiener指数值均较高,表明锦州湾春夏季浮游植物群落结构较稳定.

  6. Interactions of the algicidal bacterium Kordia algicida with diatoms: regulated protease excretion for specific algal lysis.

    Directory of Open Access Journals (Sweden)

    Carsten Paul

    Full Text Available Interactions of planktonic bacteria with primary producers such as diatoms have great impact on plankton population dynamics. Several studies described the detrimental effect of certain bacteria on diatoms but the biochemical nature and the regulation mechanism involved in the production of the active compounds remained often elusive. Here, we investigated the interactions of the algicidal bacterium Kordia algicida with the marine diatoms Skeletonema costatum, Thalassiosira weissflogii, Phaeodactylum tricornutum, and Chaetoceros didymus. Algicidal activity was only observed towards the first three of the tested diatom species while C. didymus proved to be not susceptible. The cell free filtrate and the >30 kDa fraction of stationary K. algicida cultures is fully active, suggesting a secreted algicidal principle. The active supernatant from bacterial cultures exhibited high protease activity and inhibition experiments proved that these enzymes are involved in the observed algicidal action of the bacteria. Protease mediated interactions are not controlled by the presence of the alga but dependent on the cell density of the K. algicida culture. We show that protease release is triggered by cell free bacterial filtrates suggesting a quorum sensing dependent excretion mechanism of the algicidal protein. The K. algicida / algae interactions in the plankton are thus host specific and under the control of previously unidentified factors.

  7. 20th century fluctuations in the abundance of siliceous microorganisms preserved in the sediments of the Puyuhuapi Channel (44° S, Chile Fluctuaciones en la abundancia de microorganismos silíceos preservados en los sedimentos del canal Puyuhuapi (44° S, Chile, durante el siglo XX

    Directory of Open Access Journals (Sweden)

    LORENA REBOLLEDO

    2005-09-01

    Full Text Available We present a 100-year reconstruction of siliceous export production from sediments of the Puyuhuapi Channel (44° S, 70° W in the Chilean fjords. We use accumulation rates and concentrations of diatoms and silicoflagellates, organic carbon (Corg and biogenic opal (SiOPAL as proxies of export production, and fluctuations in the contribution of freshwater diatoms as proxies of rainfall in the hinterland and river runoff. Box core sediments collected at two sites within the Puyuhuapi Channel were analyzed: Station 35 (at the head of the fjord; 56 m water depth and Station 40 (in the middle of the Channel; 270 m water depth. Surface sedimentation rates were 0.75 cm yr-1 at Station 35 and 0.25 cm yr-1 at Station 40. SiOPAL content averaged ~ 4 % at both sites. Diatom accumulation rates as well as the contribution of freshwater diatoms were higher at the head of the fjord (1.59 10(10 valves m-2 yr-1 and 22 %, respectively than in its middle (1.08 10(10 valves m_2 yr_1 and 14 %, respectively. Diatom abundances were two orders of magnitude higher than silicoflagellate contribution at both sites. In general, diatoms typical of high nutrient environments characterize the Puyuhuapi Channel sediments: at both sites, spores of the genus Chaetoceros dominated the diatom assemblage (> 40 % of total diatoms; spores of Chaetoceros radicans/cinctus, Ch. constrictus/vanheurcki, Ch. debilis and Ch. diadema. Downcore analysis reveals an overall increase in the production of siliceous microorganisms from the late 19th century to the early 1980s, and then a decrease until the late-1990s. We associate a decrease in freshwater diatom contribution since the mid-1970s which we associate with a concomitant decline in rainfall in the Chilean fjords. We suggest that this decline is related to the global atmospheric and oceanic warming of the past ~ 25 yearsSe presenta una reconstrucción de 100 años de la productividad silícea exportada en sedimentos del canal Puyuhuapi

  8. Structure of late summer phytoplankton community in the Firth of Lorn (Scotland) using microscopy and HPLC-CHEMTAX

    Science.gov (United States)

    Brito, Ana C.; Sá, Carolina; Mendes, Carlos R.; Brand, Tim; Dias, Ana M.; Brotas, Vanda; Davidson, Keith

    2015-12-01

    The Firth of Lorn is at the mouth of one of Scotland's largest fjordic sea lochs, Loch Linnhe. This sea loch, which is fed by a number of other inner lochs, supplies a significant flow of freshwater, which frequently causes the stratification of the water column. To investigate how environmental conditions influence the spatial distribution of phytoplankton in this region water samples were collected for phytoplankton (pigments and microscopy), and other environmental variables including nutrients. Chemotaxonomy was used to estimate the contribution of different taxonomic groups to total chlorophyll a (phytoplankton biomass index). Good agreement was obtained between chemotaxonomy and microscopy data. The highest levels of chlorophyll a (˜2.6 mg m-3) were found in the vicinity of Oban Bay, where cryptophytes, the most abundant group, dinoflagellates and other flagellates thrived in the stratified water column. Centric diatoms, mainly Chaetoceros sp. and Skeletonema costatum, were associated with NH4 and SiO2 concentrations and stratification, while pennate diatoms, mainly Cylindrotheca sp. and Nitzchia sp., were found to be associated with NO3 + NO2 and high surface mixed layer depths. Four diatom groups were identified in accordance to their surface to volume ratios, as well as their affinity to environmental parameters (nutrients) and turbulence. This study used a combination of physico-chemical data, classical microscopy methods (appropriate for large cells > 20 μm) and HPLC-CHEMTAX approaches (for large and small cells) to evaluate the distribution of phytoplankton functional groups in a fjordic coastal area.

  9. A suggested local regions in the Southern Gulf of Mexico using a diatom database (1979-2002) and oceanic hidrographic features.

    Science.gov (United States)

    Licea, Sergio; Zamudio, Ma E; Moreno-Ruiz, J L; Luna, R

    2011-07-01

    A diatom data-base of 255 species obtained from 14 oceanographic cruises (14801 entries of 647 sampling sites) together with the analysis of oceanic features were used to establish four local regions in the southern Gulf of Mexico. In addition, common species for each region were designated. This study is based on the application of cluster analysis and the species frequency data. Material for this undertaking consisted of water and net samples obtained between June 1979 and December 2002. Results show that the most frequent species (> 40%) were: Asterionellopsis glacialis, Bacteriastrum delicatulum, B. hyalinum, Chaetoceros affinis, C. coarctatus, C. compresus, C. curvisetus, C. danicus, C. decipiens, C. diversus, C. lorenzianus, C. pelagicus, C. peruvianus, Coscinodiscus radiatus, Cylindrotheca closterium, Guinardia flaccida, Hemiaulus hauckii, H. membranaceus, H. sinensis, Leptocylindrus danicus, Neocalyptrella robusta, Nitzschia bicapitata, Pleurosigma diverse-striatum, Proboscia alata, Pseudo-nitzschia pungens, Pseudosolenia calcar-avis, Rhizosolenia imbricata, R. setigera, Skeletonema costatum, Thalassionema bacillare, T frauenfeldii, T nitzschioides and Thalassiosira eccentrica. The species composition for each region and season are discussed. Itis concluded that sampling site assemblages are related to oceanographic conditions. A total list of species composition is given, forty-seven species taxa being new records for this area. PMID:22315823

  10. Interactions of the algicidal bacterium Kordia algicida with diatoms: regulated protease excretion for specific algal lysis.

    Science.gov (United States)

    Paul, Carsten; Pohnert, Georg

    2011-01-01

    Interactions of planktonic bacteria with primary producers such as diatoms have great impact on plankton population dynamics. Several studies described the detrimental effect of certain bacteria on diatoms but the biochemical nature and the regulation mechanism involved in the production of the active compounds remained often elusive. Here, we investigated the interactions of the algicidal bacterium Kordia algicida with the marine diatoms Skeletonema costatum, Thalassiosira weissflogii, Phaeodactylum tricornutum, and Chaetoceros didymus. Algicidal activity was only observed towards the first three of the tested diatom species while C. didymus proved to be not susceptible. The cell free filtrate and the >30 kDa fraction of stationary K. algicida cultures is fully active, suggesting a secreted algicidal principle. The active supernatant from bacterial cultures exhibited high protease activity and inhibition experiments proved that these enzymes are involved in the observed algicidal action of the bacteria. Protease mediated interactions are not controlled by the presence of the alga but dependent on the cell density of the K. algicida culture. We show that protease release is triggered by cell free bacterial filtrates suggesting a quorum sensing dependent excretion mechanism of the algicidal protein. The K. algicida / algae interactions in the plankton are thus host specific and under the control of previously unidentified factors. PMID:21695044

  11. 南麂列岛海洋自然保护区浮游植物生态研究%Ecological study on netzphytoplankton in Nanji marine nature reserve area

    Institute of Scientific and Technical Information of China (English)

    张晓辉; 周燕; 张成; 余俊; 卢毅军

    2009-01-01

    研究了南麂列岛海洋自然保护区浮游植物物种组成、数量分布、多样性指数及其与营养盐、浮游动物的关系.经鉴定,共发现浮游植物86种,隶属于33属.网样浮游植物平均密度为194.00×104个/m3,水样浮游植物平均密度为4.98×104个/m3,优势类群有角毛藻(Chaetoceros sp.)、角藻(Ceratuym sp.)、中肋骨条藻(Skeletonema costatum)、红色裸甲藻(Akashiwo sanyuineum)等.网样浮游植物多样性平均指数为2.28,水样浮游植物多样性平均指数为2.17.根据浮游植物组成特点,将其分为两个生态类群:近岸性和广布性类群,外海性类群.

  12. SEASONAL ASSESSMENT OF HYDROGRAPHIC VARIABLES AND PHYTOPLANKTON COMMUNITY IN THE ARABIAN SEA WATERS OF KERALA, SOUTHWEST COAST OF INDIA

    Directory of Open Access Journals (Sweden)

    Sushanth Vishwanath Rai

    2014-12-01

    Full Text Available The seasonal variation of the hydrographic variables and phytoplankton species in the Arabian Sea waters of the Kerala coast, Southern India was investigated during different seasons. The variables such as pH, temperature, salinity, turbidity and chlorophyll-a contents of water were found to be high during pre-monsoon season and the dissolved oxygen content was minimal. The concentration of nutrients viz., nitrate, phosphate, silicate varied independently. In the study a total of 53 species of phytoplankton were recorded. Their density was higher during the post-monsoon season than during other seasons and the diatoms were found to be the dominant species. The major phytoplankton in terms of frequency and abundance were the species namely, Biddulphia mobiliensis, Chaetoceros curvisetus, Licmophora abbreviata, Skeletonema costatum, Prorocentrum micans and Oscillatoria sp. They showed significant positive correlation with pH, temperature, salinity, nitrate, phosphate and chlorophyll-a contents, whereas turbidity, dissolved oxygen and silicate exhibited significant negative correlation. The Principal Component Analysis (PCA developed two principal components with 84.74% of total variability in the water quality which separated pre- and post-monsoon periods from the monsoon season on axis I, and pre-monsoon and monsoon periods from post-monsoon on axis II.

  13. 胶州湾赤潮生物种类及其生态分布特征%Harmful algae bloom species in Jiaozhou Bay and the features of distribution

    Institute of Scientific and Technical Information of China (English)

    韩笑天; 邹景忠; 张永山

    2004-01-01

    近年来,胶州湾赤潮发生频繁,对海水养殖业、海洋环境乃至人类健康与安全都构成威胁,作者根据 1997年 6~ 9月和 1998年 4~ 9月采于胶州湾东北部富营养化海域的样品及有关历史资料,报道了赤潮生物 69种, 其中已发生过的赤潮种类有 7种,分析了中肋骨条藻 Skeletonema costatum、圆筛藻 Coscinodiscus sp.、冰河拟星杆藻(日本星杆藻) Asterionellopsis glacialis、劳氏角毛藻 Chaetoceros lorenzianus、红色中缢虫 Mesodinium rubrum等主要赤潮生物的生态分布特征.

  14. [Yearly Changes of Phytoplankton Community in the Ecology-monitoring Area of Changli, Hebei in Summer].

    Science.gov (United States)

    Liang, Xiao-lin; Yang, Yang; Wang, Yu-liang; Zhang, Yue-ming; Zhao, Zhi-nan; Han, Xiao-qing; Zhang, Jian-da; Gao, Wei-ming

    2015-04-01

    Based on the investigation of phytoplankton and water body nutrient concentration in the ecology-monitoring area of Changli in summer from 2005 to 2013, the phytoplankton community structure was analyzed. The result showed that in recent 9 years, 3 phyla including 23 families, 39 genera and 105 species of phytoplankton were identified, in which 85.7% were diatoms and 13.3% were dinoflagellate. Only one species was found belonging to golden algae. There was great difference in dominant species among different years. According to the value of dominance, there were Coscinodiscus radiatus, Coscinodiscus debilis, Rhizosolenia styliformis, Cerataulina bergoni, Coscinodiscus wailesii, Thalassiosira sp., Ceratium tripos, Chaetoceros lorenzianus, Skeletonema costatum. The cell abundance was decreased yearly. The Shannon-Wiener index of phytoplankton community ranged from 0.015 to 3.889, and the evenness index ranged from 0.009 to 1, which showed little yearly change. And phytoplankton species were unevenly distributed among the 19 sites, there were relatively low amount of dominant species, but the dominance was relatively high. Canonical Correspondence Analysis (CCA) results of the phytoplankton community and its environmental factors showed that the environmental factors influencing the change of phytoplankton community structure in summer included water temperature, nutrients (TP, TN and NO3(-) -N, NH4(+)-N) and salinity, and the structural change was the result of the interactions of different environmental factors. PMID:26164906

  15. Phytoplankton taxonomy based on CHEMTAX and microscopy in the northwestern Black Sea

    Science.gov (United States)

    Eker-Develi, Elif; Berthon, Jean-François; Canuti, Elisabetta; Slabakova, Natalya; Moncheva, Snejana; Shtereva, Galina; Dzhurova, Boryana

    2012-06-01

    Abundance and carbon biomass of different phytoplankton groups obtained by microscopy were compared with taxonomy derived from pigment measurements and CHEMTAX analysis of samples collected in June 2006 in the NW Black Sea. The diatom Chaetoceros curvisetus was dominant in terms of carbon biomass based on cell volume at inshore stations, while the coccolithophore Emiliania huxleyi was prevalent at offshore. Emiliania huxleyi reached bloom abundance of 3.3 × 106 cells L- 1. The chlorophyll a (chl a) concentration within phytoplankton groups as allocated by CHEMTAX was in agreement with microscopy derived carbon biomasses of the taxonomic groups diatoms, dinoflagellates and cryptophytes only. Carbon biomass of less abundant phytoplankton taxa (cyanophytes, euglenophytes and chlorophytes) did not correlate with group-specific chl a. It was not possible to detect E. huxleyi bloom by CHEMTAX analysis probably due to much higher biomass of other species containing 19'-hexanoyloxyfucoxanthin. Nutrient concentrations were generally high in the waters where diatom and dinoflagellates dominated the community but low in the area of E. huxleyi bloom. A good correlation between total carbon biomass of phytoplankton and chl a was found and the estimated C:chl a ratio of phytoplankton varied between 36 and 256 (in average 124 ± 50).

  16. High interglacial diatom paleoproductivity in the westernmost Indo-Pacific Warm Pool during the past 130,000 years

    Science.gov (United States)

    Romero, Oscar E.; Mohtadi, Mahyar; Helmke, Peer; Hebbeln, Dierk

    2012-09-01

    A wealth of sedimentary records aimed at reconstructing late Quaternary changes in productivity and temperature have been devoted to understanding linkages between the Indo-Pacific Warm Pool (IPWP) and other distant oceanic areas. Most of these reconstructions are based, however, on biogeochemical and sedimentological proxies, with comparatively less attention devoted to microfossils. A high-resolution (cycle. The diatom record provides evidence that diatom paleoproductivity was highest during interglacials, primarily due to the input of lithogenics and nutrients following the rise in sea level after full glacials. In addition, the co-variation of total diatom concentration and Northern Hemisphere forcing for Marine Isotope Stage 5 suggests a direct response of diatom productivity and upwelling intensity to boreal summer insolation. Temporal shifts of the diverse diatom community at site GeoB10038-4 correspond well with the present-day seasonal monsoon pattern and the strengthening and weakening phases of upwelling along the southern coast of Sumatra. Resting spores ofChaetoceros, typical of nutrient-rich waters, were dominant during periods of highest diatom paleoproductivity and responded to the strengthening of the SE monsoon, while diatoms of oligotrophic to mesotrophic waters characterized intermonsoon periods. The close correspondence between the dominance of upwelling diatoms and the boreal summer insolation resembles the present-day dynamics of diatom production. The observed interglacial highs and glacial lows of diatom productivity at site GeoB10038-4 is a unique pattern in the late Quaternary tropics.

  17. Deglacial diatom productivity and surface ocean properties over the Bermuda Rise, northeast Sargasso Sea

    Science.gov (United States)

    Gil, Isabelle M.; Keigwin, Lloyd D.; Abrantes, Fatima G.

    2009-12-01

    Diatom assemblages document surface hydrographic changes over the Bermuda Rise. Between 19.2 and 14.5 ka, subtropical diatom species and Chaetoceros resting spores dominate the flora, as in North Atlantic productive regions today. From 16.9 to 14.6 ka, brackish and fresh water diatoms are common and their contribution is generally coupled with total diatom abundance. This same interval also contains rare grains of ice-rafted debris. Coupling between those proxies suggests that successive discharge of icebergs might have stimulated productivity during Heinrich event 1 (H1). Iceberg migration to the subtropics likely created an isolated environment involving turbulent mixing, upwelled water, and nutrient-rich meltwater, supporting diatom productivity in an otherwise oligotrophic setting. In addition, the occurrence of mode water eddies likely brought silica-rich waters of Southern Ocean origin to the euphotic zone. The persistence of lower-salinity surface water beyond the last ice rafting suggests continued injection of fresh water by cold-core rings and advection around the subtropical gyre. These results indicate that opal productivity may have biased estimates of meridional overturning based on 231Pa/230Th ratios in Bermuda Rise sediments during H1.

  18. Evaluación del crecimiento y supervivencia en larvas de camarón blanco Litopenaeus vannamei usando como fuente de alimento microalgas vivas y congeladas

    Directory of Open Access Journals (Sweden)

    Elifonso Isiordia Pérez:

    2007-05-01

    Full Text Available Resumen matraces de 1.5 litros de capacidad con 5 El objetivo del presente rabajo fue evaluar el eplicas cada tratamiento. La densidad de efecto de una dieta monoalgal a base de dos microalgas a suministrar fue de 50,000 células presentaciones Tetraselmis sp. (vivas y / mililitro. Conforme mudaban de estadio se congeladas:producto comercial: INLAND hacía conteo de organismos vivos y se media Seafarm® en la supervivencia y crecimiento longitud El mayor porcentaje de supervivencia en larvas de camarón blanco Litopenaeus y crecimiento se registró en las larvas vannamei en estadios larvales desde limentadas con Tetraselmis sp. vivas (97.3 Protozoea 1 (PZ1 a Protozoea 3 (PZ3. El ±4.6 en PZI, 94.1 ± 2.13 en PZ2 y 30.7±12.6 experimento se realizó en las instalaciones del en PZ3. Sin embargo este resultado no es Centro de Investigación en Alimentación y comparable a los obtenidos con otras especies Desarrollo (CIAD, Unidad Mazatlán Sinaloa. El de microalgas como Chaetoceros muelleri e estudio se realizó bajo condiciones controladas Isochrysis galbana. de temperatura (28°C, salinidad (35‰ y fotoperiodo (12 h luz / oscuridad. Se sembraron 150 organismos en nauplio V en

  19. Compositional Similarities and Differences between Transparent Exopolymer Particles (TEP) from two Marine Bacteria and two Marine Algae: Significance to Surface Biofouling

    KAUST Repository

    Li, Sheng

    2015-06-12

    Transparent-exopolymer-particles (TEP) have been recently identified as a significant contributor to surface biofouling, such as on reverse osmosis (RO) membranes. TEP research has mainly focused on algal TEP/TEP precursors while limited investigations have been conducted on those released by bacteria. In this study, TEP/TEP precursors derived from both algae and bacteria were isolated and then characterized to investigate their similarities and/or differences using various advanced analytical techniques, thus providing a better understanding of their potential effect on biofouling. Bacterial TEP/TEP precursors were isolated from two species of marine bacteria (Pseudidiomarina homiensis and Pseudoalteromonas atlantica) while algal TEP/TEP precursors were isolated from two marine algae species (Alexandrium tamarense and Chaetoceros affinis). Results indicated that both isolated bacterial and algal TEP/TEP precursors were associated with protein-like materials, and most TEP precursors were high-molecular-weight biopolymers. Furthermore all investigated algal and bacterial TEP/TEP precursors showed a lectin-like property, which can enable them to act as a chemical conditioning layer and to agglutinate bacteria. This property may enhance surface biofouling. However, both proton nuclear magnetic resonance (NMR) spectra and the nitrogen/carbon (N/C) ratios suggested that the algal TEP/TEP precursors contained much less protein content than the bacterial TEP/TEP precursors. This difference may influence their initial deposition and further development of surface biofouling.

  20. Effect of diet quality on mussel biomarker responses to pollutants.

    Science.gov (United States)

    González-Fernández, Carmen; Lacroix, Camille; Paul-Pont, Ika; Le Grand, Fabienne; Albentosa, Marina; Bellas, Juan; Viñas, Lucía; Campillo, Juan A; Hegaret, Helene; Soudant, Philippe

    2016-08-01

    The effect of the quality of two microalgal species on select biological and biochemical responses used as indicators of pollution were assessed. Mussels were conditioned for 6 weeks with the diatom Chaetoceros neogracile and the dinoflagellate Heterocapsa triquetra, chosen for being two clearly different types of primary production quality that differ in both biometric and biochemical characteristics. After dietary conditioning, the mussels were exposed to a polycyclic aromatic hydrocarbon, fluoranthene (FLU), for 1 week followed by 1 week of depuration. Results showed higher FLU accumulation in mussels fed on C. neogracile compared to those fed on H. triquetra. Concomitantly, a greater impact of this toxicant was observed in the biomarker responses of mussels fed on C. neogracile. These mussels showed an increase in the percentage of dead hemocytes, an activation of phagocytosis and ROS production of hemocytes after exposure. Some enzymatic activities also increased upon FLU exposure (superoxide dismutase -SOD-, catalase -CAT-, and glutathione reductases -GR-) and after depuration (glutathione-s-transferase -GST-). Results suggest that FLU exposure as well as food quality influence biomarker responses, with higher values of SOD, CAT and GR in non-exposed mussels fed on C. neogracile. In addition, upon exposure to the same FLU concentration, GR response varied according to dietary conditioning, suggesting that diet could act as a confounding factor in biomarker responses to pollution. Consequently, trophic conditions should be considered in marine pollution monitoring programs for a better interpretation of biomarker responses. PMID:27300503

  1. Accumulation of tritium in aquatic organisms through a food chain with three trophic levels

    International Nuclear Information System (INIS)

    Accumulation of tritium in aquatic organisms was estimated through a model food chain such as; tritiated water (THO) → diatoms → brine shrimps → Japanese killifish. Tritium accumulations in each organism as organic bound form are expressed as the R value which is defined as the ratio of tritium specific activity in lyophilized organisms (μCi/gH) to that in water (μCi/gH). The maximum R values were 0.5 in diatoms, Chaetoceros gracilis, 0.5 in brine shrimps, Artamia salina, and 0.32 in Japanese killifish, Oryzias latipes under the growing condition where tritium accumulation took place from tritiated water without tritiated diets. Brine shrimps and Japanese killifish, which grew from larvae to adult in tritiated sea water with feeding on tritiated diets (model food chain), had the R value at 0.70 and 0.67 respectively, indicating that more tritium accumulation in consumer populations with tritiated diets than those without tritiated diets. In addition, the R values of each organ of Japanese killifish, of DNA and the nucleotides purified from brine shrimps growing under the condition with or without our model food chain were measured to estimate the tritium distribution in the body or various components of the organism. These results did not indicate the seeking characteristic of tritium to some specific organs of compounds. (author)

  2. Application of a laser fluorometer for discriminating phytoplankton species

    Science.gov (United States)

    Chen, Peng; Pan, Delu; Mao, Zhihua

    2015-04-01

    A portable laser-induced fluorescence system for discriminating phytoplankton species has been developed. It consists of a high pulsed repetition frequency (10-kHz) microchip laser at 405 nm, a reflective fluorescent probe and a broadband micro spectrometer. The measured fluorescent spectra were overlapped by various fluorescent components, and were then decomposed by a bi-Gaussian mixture model. A spectral shape description index was designed to characterize fluorescent spectral shapes for descriminating the phytoplankton species cultured in our laboratory. Using clustering analysis, the samples of eight phytoplankton species belonging to two divisions of Bacillariophyta and Dinophyta were divided into six categories: 1) Chaetoceros debilis, Thalassiosira rotula; 2) Prorocentrum donghaiense, Prorocentrum dentatum; 3) Gymnodinium simplex; 4) Alexandrium tamarense; 5) Karenia mikimotoi; and 6) Akashiwo sanguinea. The phytoplankton species belonging to Bacillariophyta were well separated from those belonging to Dinophyta. In addition, the phytoplankton species belonging to Dinophyta were successfully distinguished from each other at genus level. The portable system is expected to be used both in vivo and in the field.

  3. PHYTOPLANKTON ASSEMBLAGES AT FISH FARM IN MASLINOVA BAY (THE ISLAND OF BRAČ

    Directory of Open Access Journals (Sweden)

    Sanda Skejić

    2012-07-01

    Full Text Available The aim of this study was to establish phytoplankton composition at the sea bream (Sparus aurata and sea bass (Dicentrarchus labrax fish farm in the middle Adriatic Sea. The investigation was performed from September 2005 to September 2006 at a station located in Maslinova Bay at the island of Brač. Considering the whole research period, diatoms generally prevailed in terms of abundance while dinoflagellates were particularly abundant in June. Number of species of diatoms in comparison to dinoflagellates through the investigated period was similar. From 111 species of phytoplankton found, there were 55 species of Bacillariophyceae (diatoms, 47 species of Dinophyta (dinoflagellates, 5 species of Prymnesiophyceae, 3 Chrysophyceae and 1 Euglenophyta. Among the diatoms, the majority of species belonged to genus Chaetoceros. The most represented dinoflagellate genera were Oxytoxum and Gymnodinium. There were no considerable differences in phytoplankton composition with respect to different depths, but seasonal influence was significant. Biodiversity and abundance ranges of phytoplankton species indicated good water conditions and there were no evident alterations induced by the increased release of nutrients.

  4. Cadmium and zinc capture capacity by bacteria, microalgae and yeast

    Directory of Open Access Journals (Sweden)

    María Elena Carballo

    2012-09-01

    Full Text Available The elimination of toxic heavy metals present in wa-tery solutions has been performed with the employ-ment of biosorbent materials coming from microbial sources, considering the capacities they have for the metallic ions uptake. Microbial sivings to deter-mine metal uptake level is the base in order to find appropriate biosorbents for its application in this process, aspect that has been the principal objective in the present work. The cadmium and zinc uptake capacity was evaluated in different microorganisms such as Gram positive and Gram negative bacterias, phototrophic bacteria, microalgae and yeasts. The capture levels of both metals were variable among the strains, which indicate different uptake capaci-ties of cadmium and zinc. The best biosorbents from 64 analyzed microorganisms were: isolated bacteria CB-M4 y A-6, Pseudomonas mendocina, Anabaena sp. PCC 7120, Anabaena variabilisATCC 29413, Chloroglocopsis fritschii, Chaetoceros ceratospho-rus, Tetraselmis suesica,isolated microalgae CM3, CM5, CM6 y CMV and the strains 10 and 12 of the yeast Saccharomyces cerevisiae.

  5. A metabolic profile in Ruditapes philippinarum associated with growth-promoting effects of alginate hydrolysates

    Science.gov (United States)

    Yamasaki, Yasuhiro; Taga, Shigeru; Kishioka, Masanobu; Kawano, Shuichi

    2016-07-01

    The aim of this study is to demonstrate the growth-promoting effect of alginate hydrolysates (AHs) on the Manila clam Ruditapes philippinarum, and to verify the physiological change occurring within a living R. philippinarum stimulated by AHs. We show that growth of clams was dramatically promoted by supplementing a diet of the diatom Chaetoceros neogracile with AHs at 4 mg/mL. Furthermore, metabolomics indicates that each state of starvation, food satiation, and sexual maturation have a characteristic pattern. In the groups given AHs in addition to C. neogracile in particular, excess carbohydrate was actively utilized for the development of reproductive tissue. In contrast, it appeared that clams in the groups given C. neogracile only were actively growing, utilizing their adequate carbohydrate resources. Meanwhile, the unfed groups have slowed growth because of the lack of an energy source. Hence, supplementation of AHs in addition to the algal diet may be an inexpensive way to shorten the rearing period of R. philippinarum. Moreover, metabolomics can evaluate the growth condition of R. philippinarum in a comprehensive way, and this approach is crucially important for not only the development of a mass culture method but also for the conservation of the clam resource in the field.

  6. Distribution of diatoms in the water and surface sediments of southern South China Sea

    Institute of Scientific and Technical Information of China (English)

    LU Jun; CHEN Muhong; CHEN Zhong

    2006-01-01

    The relationship of species and abundance between the diatoms in the water and sediments from the southern South China Sea (SCS) were discussed, and the key environmental controlling factors were also investigated. Studies show that the diatom abundance is high in both water and sediments in the southeast part of the southern SCS and the varying trend is similar, while in the northwest part, the abundance is low, and the varying trend is different. The dominant diatom species are Thalassionema nitzschioides and Nitzschia bicapitata in water, and T. nitzschioides and Chaetoceros messanensis in sediments. The diatom species of small size and thin shell in water are more than in the sediments, while the diatom species of large size and thick shell in water are less. The percentage of species T. nitzschioides is higher in water of southeast part than in that of northwest part, but it is similar in sediments of both areas. It is shown that the southwest monsoon is the important factor influencing diatom abundance and T. nitzschioides percentage,and when the southwest monsoon is well developed,the distribution of diatom abundance and T. nitzschioides percentage are consistent in both water and sediments of the study area.

  7. Microbenthic community structure and trophic status of sediments in the Mar Piccolo of Taranto (Mediterranean, Ionian Sea).

    Science.gov (United States)

    Rubino, F; Cibic, T; Belmonte, M; Rogelja, M

    2016-07-01

    This study aimed to assess the benthic ecosystem trophic status in a heavily polluted marine area and the response of the microbenthic community to multiple and diffuse anthropogenic impacts, integrating information coming from the active and resting (plankton's cysts) components of microbenthos. Two sampling campaigns were carried out in the period 2013-2014 and four sampling sites at different levels of industrial contamination were chosen within the first and second inlet of the Mar Piccolo of Taranto. The chemical contamination affected to a higher extent the active microbenthos than the resting one. In the central part of the first inlet, characterised by more marine features, thrives a very rich and biodiverse microbenthic community. In contrast, at the polluted site near the military navy arsenal, extremely low densities (9576 ± 1732 cells cm(-3)) were observed for active microbenthos, but not for the resting community. Here, the high level of contamination selected for tychopelagic diatom species, i.e., thriving just above the surface sediments, while the other life forms died or moved away. Following the adoption of a 10 μm mesh, for the first time, resting spores produced by small diatoms of the genus Chaetoceros were found. Our results further indicate that although the Mar Piccolo is very shallow, the benthic system is scarcely productive, likely as a consequence of the accumulated contaminants in the surface sediments that probably interfere with the proper functioning of the benthic ecosystem. PMID:26511257

  8. Bacterial and protist community changes during a phytoplankton bloom

    KAUST Repository

    Pearman, John K.

    2015-10-01

    The present study aims to characterize the change in the composition and structure of the bacterial and microzooplankton planktonic communities in relation to the phytoplankton community composition during a bloom. High-throughput amplicon sequencing of regions of the 16S and 18S rRNA gene was undertaken on samples collected during a 20 day (d) mesocosm experiment incorporating two different nutrient addition treatments [Nitrate and Phosphate (NPc) and Nitrate, Phosphate and Silicate (NPSc)] as well as a control. This approach allowed us to discriminate the changes in species composition across a broad range of phylogenetic groups using a common taxonomic level. Diatoms dominated the bloom in the NPSc treatment while dinoflagellates were the dominant phytoplankton in the control and NPc treatment. Network correlations highlighted significant interactions between OTUs within each treatment including changes in the composition of Paraphysomonas OTUs when the dominant Chaetoceros OTU switched. The microzooplankton community composition responded to changes in the phytoplankton composition while the prokaryotic community responded more to changes in ammonia concentration.

  9. Characterisation of transparent exopolymer particles (TEP) produced during algal bloom: A membrane treatment perspective

    KAUST Repository

    Villacorte, Loreen O.

    2013-01-01

    Algal blooms are currently a major concern of the membrane industry as it generates massive concentrations of organic matter (e.g. transparent exopolymer particles [TEP]), which can adversely affect the operation of membrane filtration systems. The goal of this study is to understand the production, composition and membrane rejection of these organic materials using different characterisation techniques. Two common species of bloom-forming freshwater and marine algae were cultivated in batch cultures for 30days and the productions of TEP and other organic matter were monitored at different growth phases. TEP production of the marine diatom, Chaetoceros affinis, produced 6-9 times more TEP than the freshwater blue-green algae, Microcystis. The organic substances produced by both algal species were dominated by biopolymeric substances such as polysaccharides (45-64%) and proteins (2-17%) while the remaining fraction comprises of low molecular weight refractory (humic-like) and/ or biogenic organic substances. MF/UF membranes mainly rejected the biopolymers but not the low molecular weight organic materials. MF membranes (0.1-0.4 lm) rejected 42-56% of biopolymers, while UF membranes (10-100 kDa) rejected 65-95% of these materials. Further analysis of rejected organic materials on the surface of the membranes revealed that polysac-charides and proteins are likely responsible for the fouling of MF/UF systems during an algal bloom situation. © 2013 Desalination Publications.

  10. Phylogenetic analysis of microalgae based on highly abundant proteins using mass spectrometry.

    Science.gov (United States)

    Lee, Hae-Won; Roh, Seong Woon; Cho, Kichul; Kim, Kil-Nam; Cha, In-Tae; Yim, Kyung June; Song, Hye Seon; Nam, Young-Do; Oda, Tatsuya; Chung, Young-Ho; Kim, Soo Jung; Choi, Jong-Soon; Kim, Daekyung

    2015-01-01

    The blooms of toxic phototrophic microorganisms, such as microalgae and cyanobacteria, which are typically found in freshwater and marine environments, are becoming more frequent and problematic in aquatic systems. Due to accumulation of toxic algae, harmful algal blooms (HABs) exert negative effects on aquatic systems. Therefore, rapid detection of harmful microalgae is important for monitoring the occurrence of HABs. Mass spectrometry-based methods have become sensitive, specific techniques for the identification and characterization of microorganisms. Matrix-assisted laser desorption/ionization (MALDI) with time-of-flight (TOF) mass spectrometry (MS) allows us to measure a unique molecular fingerprint of highly abundant proteins in a microorganism and has been used for the rapid, accurate identification of bacteria and fungi in clinical microbiology. Here, we tested the specificity of MALDI-TOF MS using microalgal strains (Heterocapsa, Alexandrium, Nannochloropsis, Chaetoceros, Chlorella, and Dunaliella spp.). Our research suggested that this method was comparable in terms of the rapid identification of microalgea to conventional methods based on genetic information and morphology. Thus, this efficient mass spectrometry-based technique may have applications in the rapid identification of harmful microorganisms from aquatic environmental samples. PMID:25476355

  11. Discovery of nitric oxide in marine ecological system and the chemical characteristics of nitric oxide

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhengbin; XING Lei; WU Zhenzhen; LIU Chunying; LIN Cai; LIU Liansheng

    2006-01-01

    Nitric oxide was discovered in both the lab and the alga culture pond of Daya Bay (1-300 m3) before the growth of alga reached the maximum. The results included: (1) NO was detectd before the growth of alga reached the maximum in the case of red tide alga and food alga, and the concentration of NO decreased rapidly after the growth maximum; (2) the curve between NO concentration and time indicated that the concentration of NO in the daytime was more than that at night,and the maximal concentration of NO appeared in the midday (1-3 pm); (3) the growth of alga reached the maximum in the alga culture pond of Daya Bay in about 8- 10 d, and NO was discovered in 5-7 d; (4) the measured NO concentration was 10-9 mol/L, 10-9-10-8 mol/L, and 10-8 mol/L for Haeterosigma akashiwo, mixed alga in Daya Bay and Chaetoceros Curvisetus individually; (5) the relation of illumination with NO production was discussed.

  12. Effects of environmental stresses on the species composition of phytoplankton populations. Progress report, May 1, 1978--February 28, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Ryther, J. H.; Sanders, J. G.

    1979-02-01

    Unfiltered Vineyard Sound seawater circulated through 1000-liter fiberglass tanks at 10% volume exchange per day maintains a reasonably constant phytoplankton community that is also representative of the natural assemblage. Sixteen such tanks have been stresed with addition of free chlorine and copper, and temperature increase, in all possible combinations and at increments of 0.05 ppM Cl/sup -/, 5.0 ..mu..g/l Cu/sup + +/, and 2/sup 0/C temperature increase in experiments of 4 to 6 weeks duration. At the lowest stress level, the tank culture exposed to chlorine after 19 days had a decreased total population size, lower diversity, a similarity index significantly different from the control, and a community dominated by Skeletonema costatum, which was absent from the control culture. The copper-exposed culture showed similar but smaller effects. Chlorine and copper together cancelled each others effects. No effect was seen from a temperature increase of 2/sup 0/C alone or together with other stresses. The experiment at the next highest stress level was complicated by sub-zero temperatures and freezing input lines. The greatest effect was caused by temperature increase (+4/sup 0/C) which caused a shift from diatoms to a variety of flagellates. Diatoms, particularly S. costatum and Chaetoceros spp., remained dominant in the C/sup -/ and Cu/sup + +/ stressed culture not exposed to thermal increase.

  13. Effect of UV- B radiation on the feeding behavior of the rotifer Brachionus plicatilis

    Institute of Scientific and Technical Information of China (English)

    FENG Lei; LI Xin; WANG Jinhe; HAN Honglei; TANG Xuexi; CHEN Xiguang

    2007-01-01

    Effect of UV - B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV - B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV - B radiation on five species of microalgae, i. e. , Chlorella sp. ,Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV - B radiation when fed with five species of microalgae respectively (P < 0.05 ) which indicates UV - B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp. , then C. muelleri, I.galbana, N. clostertum and T. chuii in turn if without UV - B radiation. Under the highest dose of UV - B radiation treatment (2.70 kJ/m2) , the rotifer preferred to feed C. muelleri, then Chlorella sp. , N. clostertum, I. galbana and T. chuii in turn.Chlorella sp. , I. galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV - B radiation will lead to the change in the structure of phytoplankton community.

  14. The effects of cadmium of the growth and metallothionein expression of the bivalve larvae, crassostrea virginica

    Energy Technology Data Exchange (ETDEWEB)

    Craig, K.D. [Univ. of Charleston, WV (United States); Burnett, K.; Ringwood, A.; MacDougal, K.; Kendall, L.

    1994-12-31

    Oyster larvae, Crassostrea virginica, were exposed to 20 ppb of cadmium (Cd) and fed (mixture of Isochrysis galbana & Chaetoceros gracilis, 40mL) in the laboratory for 10 days. On the 0, 4, 7 and 10 day the larvae samples were taken and frozen. Then they were homogenized, centrifuged, ultrafiltered through a membrane separation technique used to segregate substances according to the molecular weight and size. The cytosolic protein was first partially purified by gel permeation, then by PAGE (Polyacrylamide Gel Electrophoresis). The controls and metal exposed larvae were evaluated on total wet weight and the metallothioneins (MT) were identified from the preparations using silver staining techniques. No significant changes could be detected in the controls. However, there was a great number dead at the beginning of the experiment. Cd accumulation began at the time of exposure. This suggests that surface area may play a role in determining short-term accumulation rates. Cd effects on growth (wet weight) was slightly different, the exposed weighed less than or equal to the controls. In addition, the Cd uptake via food played an insignificant role compared to direct uptake from sea water. Between day 0 and 7 there was a number of mortalities for the controls and exposed. In addition, there was a major weight change with the exposed, they appeared to weigh less than the controls on day 7, whereas on day 4 they weighed more. So weight is a very sensitive indicator of toxic stress.

  15. Spatial variability in phytoplankton community structure along the eastern Arabian Sea during the onset of south-west monsoon

    Science.gov (United States)

    Ahmed, Ayaz; Kurian, Siby; Gauns, Mangesh; Chndrasekhararao, A. V.; Mulla, Amara; Naik, Bhagyashri; Naik, Hema; Naqvi, S. W. A.

    2016-05-01

    The Arabian Sea experiences moderate to weak upwelling along the south-west coast of India, which subsequently propagates towards the north. This causes variation in plankton community composition, which is addressed in the present study. Here we report the spatial variations in distribution of phytoplankton groups along the north-south transect in the eastern Arabian Sea based on marker pigments supported with flow-cytometric and microscopic analyses. 15 phytoplankton pigments were identified using High-performance liquid chromatography (HPLC) and the chemotaxonomic software (CHEMTAX) analysis associated these to seven major group of phytoplankton. The phytoplankton biomass, chlorophyll a (Chl a) was higher in southern stations with dominance of fucoxanthin whereas, divinyl chlorophyll a (divinyl Chl a), marker pigment of Prochlorococcus was present only in the northern region. Microscopic observation revealed the dominance of larger forms; diatoms (Chaetoceros coarctatum and Nitzschia sp.) and dinoflagellates (Scrippsiella sp., Oxytoxum nanum and Oxytoxum sp.) in the southern region. Furthermore, a study of plankton size distribution showed dominance of picoplankton (fpico) followed by nanoplankton (fnano) along the northern stations with comparatively higher microplankton (fmicro) in the south. This study clearly showed the influence of different environmental conditions on the phytoplankton community as reflected in dominance of diatoms in the southern (south of 12 °N) and that of picoplankton in the northern (north of 12 °N) region.

  16. Development of virtual photobioreactor for microalgae culture considering turbulent flow and flashing light effect

    International Nuclear Information System (INIS)

    A virtual photobioreactor for mass-culturing microalgae was developed. This is a computer model system combining a numerical simulation code for two-phase turbulent flow of bubbles and continuous medium and a photosynthesis model that can express the flashing light effect. The flashing light effect should be considered because turbulent flow in the reactor gives microalgae a chance to come close to the irradiated surface in the opaque medium at irregular frequency and this intermittent illumination enhances photosynthesis of the algae. The two-phase flow model output the time history of light pass along light ray between the irradiated wall surface of the reactor and the individual algal cell, which was passively moved by turbulent flow. When the history of light intensity, which was calculated from that of the light pass and the Beer-Lambert law, experienced by the cell was given, the photosynthesis model output the amount of O2 emitted from the cell in every small time interval. Finally, the harvest of the alga was estimated from the amount of the O2. As a result, the present model system successfully predicted the algal concentration optimal for the largest O2 emission at the given light intensity and simulated the growth curve of Chaetoceros gracili.

  17. Competition within the marine microalgae over the polar dark period in the Greenland Sea of high Arctic

    Institute of Scientific and Technical Information of China (English)

    Zhang Qing; Rolf Gradinger; Zhou Qingsong

    2003-01-01

    With the onset of winter, polar marine microalgae would have faced total darkness for a period of up to 6 months. A natural autumn community of Arctic sea ice microalgae was collected for dark survival experiments from the Greenland Sea during the ARKTIS-XI/2 Expedition of RV Polarstern in October 1995. After a dark period of 161 days, species dominance in the algal assemblage have changed from initially pennate diatoms to small phytoflagellates ( < 20 μm). Over the entire dark period, the mean algal growth rate was - 0.01 d-1. Nearly all diatom species had negative growth rates, while phytoflagellate abundance increased. Resting spore formation during the dark period was observed in less than 4.5% of all cells and only for dinoflagellates and the diatom Chaetoceros spp. We assume that facultative heterotrophy and energy storage are the main processes enabling survival during the dark Arctic winter. After an increase in light intensity, microalgal cells reacted with fast growth within days. Phytoflagellates had the highest growth rate, followed by Nitzschia frigida. Further investigations and experiments should focus on the mechanisms of dark survival (mixotrophy and energy storage) of polar marine microalgae.

  18. Impact of multispecies diatom bloom on plankton community structure in Sundarban mangrove wetland, India

    International Nuclear Information System (INIS)

    Highlights: • A multispecies algal bloom was studied in coastal regions of Sundarban wetland. • Sharp changes in plankton community structure and hydrological parameters observed. • Chlorophyll a showed highest cell density (11.4 × 105 cells l−1) during bloom phase. • MODIS Aqua derived chlorophyll maps have been interpreted. - Abstract: A multispecies bloom caused by the centric diatoms, viz. Coscinodiscus radiatus, Chaetoceros lorenzianus and the pennate diatom Thalassiothrix frauenfeldii was investigated in the context of its impact on phytoplankton and microzooplankton (the loricate ciliate tintinnids) in the coastal regions of Sagar Island, the western part of Sundarban mangrove wetland, India. Both number (15–18 species) and cell densities (12.3 × 103 cells l−1 to 11.4 × 105 cells l−1) of phytoplankton species increased during peak bloom phase, exhibiting moderately high species diversity (H′ = 2.86), richness (R′ = 6.38) and evenness (E′ = 0.80). The diatom bloom, which existed for a week, had a negative impact on the tintinnid community in terms of drastic changes in species diversity index (1.09–0.004) and population density (582.5 × 103 to 50 × 103 ind m−3). The bloom is suggested to have been driven by the aquaculture activities and river effluents resulting high nutrient concentrations in this region. An attempt has been made to correlate the satellite remote sensing-derived information to the bloom conditions. MODIS-Aqua derived chlorophyll maps have been interpreted

  19. Abundance, Composition and Distribution of Phytoplankton in Calamianes, Palawan

    Directory of Open Access Journals (Sweden)

    Jules Jason C Asis

    2006-12-01

    Full Text Available Phytoplankton in Coron Bay of the Calamianes Islands, Palawan were investigated from 27-29 May2004. Samples were collected from 33 stations by filtering five 10 L buckets of surface water througha net with a 20mm mesh bag. The phytoplankton consisted of four major groups. Diatoms, showed thehighest mean density of 1432.9indivL-1. Silicoflagellates comprised the next most abundant group witha mean density of 132.3 indivL-1. Dinoflagellates followed with a mean density of 94.8 indivL-1, while thecyanobacteria (blue-green algae had a mean density of 19.4 indivL-1. The top three diatoms wereChaetoceros, Bacteriastrum and Coscinodiscus. The genus Peridinium was the most abundantdinoflagellate, while Tintinnopsis dominated the silicoflagellates. Among the cyanophytes, Trichodesmiumshowed the highest density. High phytoplankton concentrations were observed in the vicinity of a pearlfarm and in areas adjacent to mangrove forests. Overall abundance and diversity in the study area arehigher than in other similarly reef-dominated areas in the country. This may be attributed to factors onboth large and local scales.

  20. First report of Trypanosoma vivax outbreak in dairy cattle in São Paulo state, Brazil Primeiro relato de surto por Trypanosoma vivax em vacas leiteiras no estado de São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    Fabiano Antonio Cadioli

    2012-06-01

    Full Text Available This is the first description of a Trypanosoma vivax outbreak in the state of São Paulo (municipality of Lins. Fever, jaundice, decreased milk production, weight loss, profuse diarrhea, abortion, anemia, leukocytosis and hyperfibrinogenemia were observed in the affected animals. Thirty-one cows and calves died out of a total of 1080 in the herd. Three cows showed neurological symptoms like dysmetria, ataxia, muscle weakness, ptyalism, lymph node enlargement and submandibular edema. Flagellated hemoparasites were observed in blood smears. The species was diagnosed as T. vivax by means of PCR. This T.vivax strain showed resistance to diaminazene aceturate and the infection spread quickly at the herd. From the ELISA test, 599 serum samples (98.36% were positive for anti-T.vivax IgG antibodies. This outbreak occurred during a very dry period, which indicates that other factors were involved in the outbreak, such as absence of tabanids and large populations of Haematobia irritans and Stomoxys calcitrans. The increases in these populations may have been due to the use of biosolid waste from sugar and ethanol plants in the sugarcane plantations surrounding the dairy farm.Esta é a primeira descrição de um surto de Trypanosomavivax ocorrido no Estado de São Paulo, no município de Lins. Animais acometidos apresentaram febre, icterícia, diminuição da produção de leite, perda de peso, diarreia profusa, abortos, anemia, leucocitose e hiperfibrigenemia. Foram registrados 31 óbitos de vacas e bezerros em 1.080 bovinos no total. Três vacas apresentaram sintomatologia nervosa, como dismetria, ataxia e fraqueza muscular, além de ptialismo, aumento de linfonodos e edema submandibular. Hemoparasitas flagelados foram observados em esfregaços sanguíneos, e a espécie de tripanossomo foi diagnosticada como T.vivax por PCR. A cepa de T. vivax mostrou ser resistente ao tratamento com aceturato de diaminozeno e a infecção disseminou rapidamente no

  1. Measuring insect characteristics by near-infrared spectroscopy and applications to the SIT

    International Nuclear Information System (INIS)

    Full text: Nar-infrared spectroscopy (NIRS) is commonly used to measure characteristics of biological materials such as grain protein, milk fat content, and pharmaceutical quality. This presentation will report the application of NIRS to measuring characteristics of insects such as sex, species, and age. Sexing: We have used NIRS to determine the sex of tsetse (Glossina spp) pupae where significant differences have been found between the spectra of male and female pupae. The differences appear to be maximized four to five days before emergence of the adults. Tsetse fly pupae up to five days before emergence can be sexed and automatically sorted with accuracies that ranged from 80 to 100%. This near-infrared technique was also used in sexing pupae of the house fly, Musca domestica Linnaeus (Diptera: Muscidae), face fly, M. autumnalis deg.eer (Diptera: Muscidae), secondary screwworm, Cochliomyia macellaria (Fabricius) (Diptera: Calliphoridae), primary screwworm fly, C. hominivorax (Coquerel) (Diptera: Calliphoridae), and stable flies, Stomoxys calcitrans (Linnaeus) (Diptera: Muscidae) but had lower classification accuracies of 50-74%. The reason for this lower classification accuracy when compared to G. pallidipes flies might be based on the difference on reproductive physiology between these different fly groups. These results could possibly be improved if a spectrometer with an extended wavelength range was used. We have also conducted preliminary studies to sex mosquito pupae and adults, and preliminary investigations look promising. About 40 male and female Anophelese gambiae G3 mosquitoes were sexed with 100% accuracy. The size difference between the males and females may have influenced classifications. About 200 An. arabiensis pupae were scanned and differences in the male and female average spectra were observable. Subsequent tests of about 200 An. gambiae pupae showed possible differences in male and female spectra. While using NIRS to sex mosquito adults

  2. The sterile insect technique in integrated pest management programmes for the control of stable flies and horn flies

    International Nuclear Information System (INIS)

    Two large integrated pest management programmes involving the control of horn flies, Haematobia irritans L., and stable flies, Stomoxys calcitrans L., have been carried out by U.S. Department of Agriculture scientists. The horn fly project was conducted on the island of Molokai, Hawaii. Its aims were to control the fly population by the insect growth regulator (IGR) methoprene (isopropyl (E,E)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate), which was metered into the drinking water of the cattle, and the release of sterile insects. The flies were released daily after exposing the young adults to 2.5 kR. There was excellent survival of the released flies. The release of sterile flies was discontinued after week 21 and no flies were observed on the cattle after week 23. No horn fly larvae could be found in any manure pats in the field after week 16. Horn-fly-infested cattle were moved into the area on week 30 and the fly population increased so the methoprene treatment was terminated on week 39. By week 44 the fly population had returned to normal. The stable fly population was suppressed on the island of St. Croix using sterile insect releases plus conventional control techniques. These included toxic traps, larviciding breeding sites and the release of parasites. The sterile insects, about 1X105/day, were released at 2km intervals over the 218km2 island for an 18-month period. For the last six months of the study more than 99.9% of the wild flies were eliminated from the island. However, a few fertile flies were found throughout the study. These fertile flies either came from small isolated breeding sites in the urban areas were no sterile flies were released, or were carried in by boats or planes with domestic livestock from the other islands in the area. (author)

  3. Development of a novel walk-through fly trap for the control of horn flies and other pests on pastured dairy cows.

    Science.gov (United States)

    Denning, S S; Washburn, S P; Watson, D W

    2014-07-01

    A prototype walk-through fly vacuum system, designed to remove horn flies Haematobia irritans (L.) (Diptera: Muscidae) from cattle, was developed and tested for efficacy. The study was conducted during 4 fly seasons over 17 consecutive weeks each year within the months of May through September at 1 dairy research herd in the coastal plain of North Carolina. Additional data on horn flies, as well as face flies (Musca autumnalis) and stable flies (Stomoxys calcitrans), were collected during 1 yr from 7 commercial pasture-based and organic dairy farms in the piedmont region of North Carolina. The number of flies observed on animals in the pasture was compared with the number of flies collected in the trap. Studies were initiated after horn fly densities had met or exceeded a threshold of 200 flies per animal. The vacuum trap removed between 1.3 and 2.5 million flies annually from the research station cattle. Most fly removal occurred during the first few weeks of operation and maintained densities below threshold thereafter. Cattle using the fly trap at the research farm had only about 28% the number of horn flies as untreated cattle, and reductions ranged from 67.5 to 74.5% across the 4-yr study. In addition to large numbers of horn flies, traps placed on commercial dairies during 1 yr collected stable flies, face flies, and house flies, all species with differing behavior and larger in size than horn flies. The estimated cost of running the trap is $72 per season at commercial rates of $0.12 per hour and an expected 4h of daily operation during the time of milking. Use of a vacuum system as described herein has potential as a cost-effective method in reducing populations of parasitic flies in pasture-based dairy production systems without the use of insecticides. PMID:24792800

  4. Hyaluronidase of bloodsucking insects and its enhancing effect on leishmania infection in mice.

    Directory of Open Access Journals (Sweden)

    Vera Volfova

    Full Text Available BACKGROUND: Salivary hyaluronidases have been described in a few bloodsucking arthropods. However, very little is known about the presence of this enzyme in various bloodsucking insects and no data are available on its effect on transmitted microorganisms. Here, we studied hyaluronidase activity in thirteen bloodsucking insects belonging to four different orders. In addition, we assessed the effect of hyaluronidase coinoculation on the outcome of Leishmania major infection in BALB/c mice. PRINCIPAL FINDINGS: High hyaluronidase activity was detected in several Diptera tested, namely deer fly Chrysops viduatus, blackflies Odagmia ornata and Eusimilium latipes, mosquito Culex quinquefasciatus, biting midge Culicoides kibunensis and sand fly Phlebotomus papatasi. Lower activity was detected in cat flea Ctenocephalides felis. No activity was found in kissing bug Rhodnius prolixus, mosquitoes Anopheles stephensi and Aedes aegypti, tse-tse fly Glossina fuscipes, stable fly Stomoxys calcitrans and human louse Pediculus humanus. Hyaluronidases of different insects vary substantially in their molecular weight, the structure of the molecule and the sensitivity to reducing conditions or sodium dodecyl sulphate. Hyaluronidase exacerbates skin lesions caused by Leishmania major; more severe lesions developed in mice where L. major promastigotes were coinjected with hyaluronidase. CONCLUSIONS: High hyaluronidase activities seem to be essential for insects with pool-feeding mode, where they facilitate the enlargement of the feeding lesion and serve as a spreading factor for other pharmacologically active compounds present in saliva. As this enzyme is present in all Phlebotomus and Lutzomyia species studied to date, it seems to be one of the factors responsible for enhancing activity present in sand fly saliva. We propose that salivary hyaluronidase may facilitate the spread of other vector-borne microorganisms, especially those transmitted by insects with high

  5. Efficacy and safety of catnip (Nepeta cataria) as a novel filth fly repellent.

    Science.gov (United States)

    Zhu, J J; Zeng, X-P; Berkebile, D; DU, H-J; Tong, Y; Qian, K

    2009-09-01

    Catnip (Nepeta cataria) is known for its pseudo-narcotic effects on cats. Recently, it has been reported as an effective mosquito repellent against several Aedes and Culex species, both topically and spatially. Our laboratory bioassays showed that catnip essential oil (at a dosage of 20 mg) resulted in average repellency rates of 96% against stable flies, Stomoxys calcitrans (L.) and 79% against houseflies, Musca domestica (L.), respectively. This finding suggested that the application of repellent could be used as part of filth fly management. Further evaluations of catnip oil toxicity were conducted to provide a broad-spectrum safety profile of catnip oil use as a potential biting and nuisance insect repellent in urban settings. Acute oral, dermal, inhalation, primary dermal and eye irritation toxicity tests were performed. The acute oral LD(50) of catnip oil was found to be 3160 mg/kg body weight (BW) and 2710 mg/kg BW in female and male rats, respectively. The acute dermal LD50 was > 5000 mg/kg BW. The acute inhalation LD50 was observed to be > 10,000 mg/m3. Primary skin irritation tested on New Zealand white rabbits showed that catnip oil is a moderate irritant. Catnip oil was classified as practically non-irritating to the eye. In comparison with other U.S. Environmental Protection Agency-approved mosquito repellents (DEET, picaridin and p-menthane-3,8-diol), catnip oil can be considered as a relatively safe repellent, which may cause minor skin irritation. PMID:19712151

  6. ASSOCIATION OF ESCHERICHIA COLI WITH THE PREVALENCE OF FLIES POPULATION

    Directory of Open Access Journals (Sweden)

    Hassan Flayiah Hassan

    2013-01-01

    Full Text Available Mass releases of house fly Musca domestica (L and stable fly Stomoxys calcitrans (L. Produced by manure piles accumulated nearby horse stables and dairy farm village in Abu-Graib provide continuous threat to inhabitants west of Baghdad. Timing of fly’s mass release in association with the presence of Escherichia coli in manure piles was examined at these locations. Experimental result indicated that flies survived during cold period of December and January in form of larvae deep in manure piles where temperature was around 15-17°C. Once the population of fly’s larvae started to increase by the second week of February, the concentration of E. coli was up to 80×106 CFU mL-1 in manure suspension. Later when larval population reached to a maximum number by the last week of April, the concentration of E. coli in manure sample dropped down to 38×102 CFU mL-1. Similar trend was observed with the proportion of E. coli to general bacteria present in manure samples where the percent decreased from 89% in early season to 1.5% when maximum number of larvae was recorded. The correlation coefficient (R between the number of larvae and coli form bacteria was = -0.73657. These results suggest the association of larval development with the consumption of E. coli. Thus manipulation of bacterial community in manure piles may lead to possible eradication of fly’s seasonal release.

  7. Localization of subsurface fluorescent lesions using surface spectral measurements

    Science.gov (United States)

    Kolste, Kolbein

    Localization of Subsurface Fluorescent Lesions using Surface Spectral Measurements Sponsored by the National Institute of Health, Bethesda, Maryland Kolbein Kolste, Ph.D. Keith Paulsen In neurosurgical tumor resection, maximizing extent of resection plays a major role in the care of cancer patients. To date, ALA is being researched as a technique to guide tumor resection by inducing the accumulation of the endogenous fluorophore PpIX. Most research has focused on the use of blue light excitation of PpIX to visual the tumor. However, due to the high attenuation of blue light by in vivo chromophores, such as oxy- and deoxy-hemoglobin, the source of collected fluorescence emissions is confined to the top layer of cells, and the signal is subject to masking by blood on the surface of the surgical field of view. This issue is particularly a problem at the end of the resection, when the surgeon is evaluating the margin for remaining tumor, but the blue-signal is insensitive to residual tumor that may be located several millimeters beneath the surface. PpIX has an absorption band in the near infrared (NIR), where the absorption due to blood is orders of magnitude lower, enabling the excitation of a fluorophore at depth. In this work, we created a hyperspectral imaging system that attaches to a neurosurgical microscope and is capable of detecting PpIX fluorescence that has been excited at 635 nm. We utilize a dual-waveband technique from the hyperspectral to estimate depth of fluorescence origin and characterize the inherent limitations of the estimated depth. One of the major benefits of this technique is that the estimation is independent of the concentration and size of the fluorophore. This is first demonstrated in phantom studies, where the depths of multiple separate inclusions at various depths are accurately estimated. The technique is verified in animal tumor models and translated into the clinical theater, with pilot data showing the first estimation of depth of

  8. Effects of future climate change on grape and wine quality: a case study for the Aglianico grape, Campania. Italy.

    Science.gov (United States)

    Bonfante, Antonello; Gambuti, Angelita; Monaco, Eugenia; Langella, Giuliano; Manna, Piero; Orefice, Nadia; Albrizio, Rossella; Basile, Angelo; Terribile, Fabio

    2016-04-01

    Water deficits limit yields and this is one of the negative aspects of climate change. However, this applies particularly when emphasis is on biomass production (e.g. for crops like maize, wheat, etc.) but not for plants where quality, not quantity is most relevant. For example, water stress occurring during specific phenological phases of grapevine development is an important factor when producing good quality wines. It induces, for example, the production of anthocyanins and aroma precursors. Water stress due to future increases of temperature and decreases of rainfall due to climate change can, therefore, represent an opportunity to increase winegrowers' incomes. This study was carried out in Campania region (Southern Italy), an area well known for high quality wine production. Growth of the Aglianico grapevine cultivar, with a standard clone population on 1103 Paulsen rootstocks, was studied on two different types of soil: Calcisols and Cambisols occurring along a slope of 90 m length with 11% gradient. The agro-hydrological model SWAP was calibrated and applied to estimate soil-plant water status at the various crop phenological phases for three vintages (2011-2013). Then, the Crop water stress index (CWSI), as estimated by the model, was related to physiological measurements (e.g. leaf water potential), grape bunches measurements (e.g. sugar content) and wine quality (e.g. tannins). For both soils, the correlation between measurements and CWSI were high (e.g. -0.97** with sugar; 0.895* with anthocyanins in the skins). Next, the model was applied to future climate conditions (2021-2051) obtained from statistical downscaling of Global Circulation Models (AOGCM) in order to estimate the effect of the climate on CWSI and hence on vine quality. Results show that the effects of climate change on grape and wine quality are not expected to be significant for this particular grape variety when grown on these Calcisols and Cambisols. However, significant differences

  9. Command and Control of Space Assets Through Internet-Based Technologies Demonstrated

    Science.gov (United States)

    Foltz, David A.

    2002-01-01

    The NASA Glenn Research Center successfully demonstrated a transmission-control-protocol/ Internet-protocol- (TCP/IP) based approach to the command and control of onorbit assets over a secure network. This is a significant accomplishment because future NASA missions will benefit by using Internet-standards-based protocols. Benefits of this Internet-based space command and control system architecture include reduced mission costs and increased mission efficiency. The demonstration proved that this communications architecture is viable for future NASA missions. This demonstration was a significant feat involving multiple NASA organizations and industry. Phillip Paulsen, from Glenn's Project Development and Integration Office, served as the overall project lead, and David Foltz, from Glenn's Satellite Networks and Architectures Branch, provided the hybrid networking support for the required Internet connections. The goal was to build a network that would emulate a connection between a space experiment on the International Space Station and a researcher accessing the experiment from anywhere on the Internet, as shown. The experiment was interfaced to a wireless 802.11 network inside the demonstration area. The wireless link provided connectivity to the Tracking and Data Relay Satellite System (TDRSS) Internet Link Terminal (TILT) satellite uplink terminal located 300 ft away in a parking lot on top of a panel van. TILT provided a crucial link in this demonstration. Leslie Ambrose, NASA Goddard Space Flight Center, provided the TILT/TDRSS support. The TILT unit transmitted the signal to TDRS 6 and was received at the White Sands Second TDRSS Ground Station. This station provided the gateway to the Internet. Coordination also took place at the White Sands station to install a Veridian Firewall and automated security incident measurement (ASIM) system to the Second TDRSS Ground Station Internet gateway. The firewall provides a trusted network for the simulated space

  10. Modeling Potential Climatic Treeline of Great Basin Bristlecone Pine in the Snake Mountain Range, Nevada, USA

    Science.gov (United States)

    Bruening, J. M.; Tran, T. J.; Bunn, A. G.; Salzer, M. W.; Weiss, S. B.

    2015-12-01

    Great Basin bristlecone pine (Pinus longaeva) is a valuable paleoclimate resource due to the climatic sensitivity of its annually-resolved rings. Recent work has shown that low growing season temperatures limit tree growth at the upper treeline ecotone. The presence of precisely dated remnant wood above modern treeline shows that this ecotone shifts at centennial timescales; in some areas during the Holocene climatic optimum treeline was 100 m higher than at present. A recent model from Paulsen and Körner (2014, doi:10.1007/s00035-014-0124-0) predicts global potential treeline position as a function of climate. The model develops three parameters necessary to sustain a temperature-limited treeline; a growing season longer than 94 days, defined by all days with a mean temperature >0.9 °C, and a mean temperature of 6.4 °C across the entire growing season. While maintaining impressive global accuracy in treeline prediction, these parameters are not specific to the semi-arid Great Basin bristlecone pine treelines in Nevada. In this study, we used 49 temperature sensors arrayed across approximately one square kilometer of complex terrain at treeline on Mount Washington to model temperatures using topographic indices. Results show relatively accurate prediction throughout the growing season (e.g., July average daily temperatures were modeled with an R2 of 0.80 and an RMSE of 0.29 °C). The modeled temperatures enabled calibration of a regional treeline model, yielding different parameters needed to predict potential treeline than the global model. Preliminary results indicate that modern Bristlecone pine treeline on and around Mount Washington occurs in areas with a longer growing season length (~160 days defined by all days with a mean temperature >0.9 °C) and a warmer seasonal mean temperature (~9 °C) than the global average. This work will provide a baseline data set on treeline position in the Snake Range derived only from parameters physiologically relevant to

  11. Diet influence on egg production of the copepod Acartia tonsa (Dana, 1896

    Directory of Open Access Journals (Sweden)

    Priscila F. Teixeira

    2010-06-01

    Full Text Available Egg production in the copepod Acartia tonsa was evaluated using different densities of the microalgae Thalassiosira weissflogii, Chaetoceros muelleri and Isochrysis galbana. Male and female were kept under controlled conditions (salinity 30, 20°C, photoperiod 12L:12D, acclimated to the experimental conditions and left over a period of 24 h to allow copulation. Algal densities tested were equivalent in biovolume and corresponded to 0, 2.5, 5, 10, 20, 40 and 60.10³ cells.mL-1 of T weissflogii. Ten acclimated female were separated, transferred to glass bottles and exposed for further 24 h to the corresponding experimental medium. After this period, the eggs were fixed and counted. Copepod egg production reached a threshold value when T weissflogii, C. muelleri and I. galbana were supplied at 10.10³, 140.10³ and 640.10³ cells.mL-1, respectively. Mean egg production corresponded to 28.0 ± 0.5, 20.1 ± 1.0 and 22.0 ± 3.5 eggs.female-1 .day-1, respectively. Copepods fed T weissflogii showed the highest mean egg production while those fed I. galbana reached a maximum egg production when the algae were supplied at a density two- to fourfold higher, considering the biovolume of T weissflogii and C. muelleri. These differences are explained considering the different sizes of the microalgae used to feed the copepods.A produção de ovos do copépode Acartia tonsa foi avaliada utilizando diferentes densidades das microalgas Thalassiosira weissflogii, Chaetoceros muelleri e Isochrysis galbana. Machos e fêmeas foram colocados sob condições controladas (salinidade 30, 20°C, fotoperíodo 12L:12D, aclimatados às condições experimentais e mantidos juntos por 24 h para permitir a copula. As densidades de algas foram equivalentes em biovolume e corresponderam a 0, 2,5, 5, 10, 20, 40 e 60,10³ células.mL-1 de T. weissflogii. Dez fêmeas aclimatadas foram separadas, transferidas para frascos de vidro e expostas por mais 24 h ao meio experimental

  12. Assessing the factors controlling the seasonal variability of δ18Osilica in Saanich Inlet, British Columbia, Canada

    Science.gov (United States)

    De Baere, B. J.; Lücke, A.; Francois, R. H.; Cassis, D.; Moschen, R.; Leistner, F.; Wissel, H.

    2011-12-01

    . Spring was dominated by the fast-growing species Skeletonema costatum, Thalassiosira spp. and some examples of the genus Chaetoceros. The summer presented occasional blooms of diatoms such as Ditylum brightwelii, Odontella longicruris, while examples of Chaetoceros spp. were present throughout this season. The plankton during the fall was similar to that present in the spring. Initial results: over the course of the sampling period, a sea surface temperature range of more than 11°C has been recorded. In the plankton net samples, an annual δ18Osilica range of 7.3 per mille has been found. Seawater samples taken at 2 m revealed a 3.6 % annual δ18Oseawater range, whilst all 12 deeper samples feature a smaller than 1 % δ18Oseawater range. Reference cited Lücke, A., Moschen, R., Schleser, G.H. 2005. High-temperature carbon reduction of silica: A novel approach for oxygen isotope analysis of biogenic opal. Geochimica et Cosmochimica Acta 69 (6): 1423-1433.

  13. 浙闽沿岸流消退时期的浮游植物群落结构特征%Community structure of phytoplankton during the fading period of Zhemin coastal water in Taiwan Strait

    Institute of Scientific and Technical Information of China (English)

    王雨; 林茂; 林更铭; 项鹏

    2011-01-01

    浙闽沿岸流对台湾海峡的水文环境意义重大.依据国家海洋局"908"补充调查专项,通过对覆盖浙闽沿岸流海洋锋面过程的海洋生物调查研究,于2008年4月实施针对浙闽沿岸流消退时期(春季)台湾海峡锋面海域的浮游植物取样分析.结果共记录3门41属86种,其中硅藻35属76种.甲藻5属9种,蓝藻1属1种.种类组成以暖水性种类和广布性种类为主,分别占总种类的50.29%和34.17%.主要优势种为琼氏圆筛藻(Coscinodiscus jonesianus)、辐射圆筛藻(Coscinodiscus radiatus)、密联角毛藻(Chaetoceros densus)、三角角藻(Ceratium tripos).浮游植物丰度平均为137.89×104 cells/m3,与盐度存在极显著正相关关系,暖水高盐性种类有高丰度.丰度的平面分布呈现从近岸往外海、从北部向南部递增的态势.浮游植物物种多样性较为丰富,种间比例较为均匀.浮游植物群落结构反映了浙闽沿岸流与南海暖流的水文消长动态.%Zhemin Coastal Water plays an important role in marine dynamics of Taiwan Strait. According to a complemental investigation of "908" from State Oceanic Administrration, halobios were conducted in Taiwan Strait Front of Zhemin Coastal Water in April, 2009. The community structure, the abundance, the composition and distribution of phytoplankton were analysed based on investigation data. The results showed 86 species belonging to 41 genera were identified. including diatoms of 76 species in 35 genera, pyrrophyta of 9 species in 5 genera,cyanobacteria of 1 species in 1 genera. Warm water species were accounting for 50.29% while eurythermy species were accounting for 34.17%. The main dominant species included Coscinodiscus jonesianus, Coscinodiscus radiatus,Chaetoceros densus and Ceratium tripos. The average of phytoplankton abundance was 137.89×104 cells/m3. which had significantly positive correlation with salinity. Abundance distribution of phytoplankton was higher in the southern

  14. Ecologia do microfitoplâncton do estuário do rio Igarassu, PE, Brasil Microphytoplankton ecology of the Igarassu river estuary, Pernambuco State, Brazil

    Directory of Open Access Journals (Sweden)

    Bruno Machado Leão

    2008-09-01

    Full Text Available Foram realizadas coletas mensais de outubro/2002 a setembro/2003 em baixa-mar e preamar de um mesmo dia, para estudo da comunidade fitoplanctônica do estuário do rio Igarassu, relacionando-a aos parâmetros abióticos. Foram identificadas 210 espécies, distribuídas em cinco divisões. As Bacillariophyta tiveram maior representatividade, com 146 espécies, seguidas pelas Cyanophyta (26 espécies, Chlorophyta (15 espécies, Euglenophyta (12 espécies e Dinophyta (11 espécies. As espécies dominantes foram Chaetoceros curvisetus Cleve (97,8%, na preamar da estação 02, em abril/2003, Thalassionema nitzschioides Grunow (93,67%, na estação 03, na baixa-mar, em agosto/2003, Microcystis aeruginosa Kützing (88,37%, maio/2003, na baixa-mar da estação 02, Rhizosolenia hebetata (Bailey Gran (87,52%, na estação 03, na preamar de fevereiro/2003 e Thalassiosira rotula Meunier (84,18% na estação 02, durante a preamar do mês de junho/2003. A densidade microfitoplanctônica esteve associada à pluviosidade, tendo ocorrido um florescimento expressivo no fim da período chuvoso e inicio do período de estiagem. A diversidade específica e equitabilidade estiveram diretamente relacionadas à baixa-mar e período de estiagem. A partir da observação dos parâmetros ambientais e da estrutura da comunidade fitoplanctônica verificou-se que existe uma forte influência da água do mar no estuário do rio Igarassu, evidenciada pela presença de espécies neríticas e oceânicas, enquanto que, na época de maior pluviosidade ocorreu à presença dominante da Cyanophyta dulcícola Microcystis aeruginosa Kützing.Studies on the phytoplankton community and its relationship to abiotic parameters were carried out at the Igarassu River estuarine area. Plankton collections were made monthly from October/2002 to September/2003 during low and high tides on the same day. We identified 210 species, distributed in five divisions. Bacillariophyta was the most

  15. Inorganic Carbon Utilization in Some Marine Phytoplankton Species%海洋浮游藻类无机碳利用机理的研究

    Institute of Scientific and Technical Information of China (English)

    缪晓玲; 吴庆余

    2002-01-01

    In order to learn the ways and possible utilization mechanisms of dissolved inorganic carbon (DIC) in marine phytoplankton species under carbon-replete or -limited conditions, the activity of extracellular carbonic anhydrase (CA) was assayed in different pH, CO2 and DIC concentrations. Extracellular CA in Amphidinium carterae and Prorocentrum minimum was detected under carbon-replete conditions, while in Melosira sp., Phaeodactylum tricornutum, Skeletonema costatum, Thalassiosira rotula, Emiliania huxleyi and Pleurochrysis carterae, CA activity was assayed under conditions of carbon limitation. No CA activity was found even under carbon-limited conditions in Chaetoceros compressus, Glenodinium foliaceum, Coccolithus pelagicus, Gephrocapsa oceanica and Heterosigma akashiwo. In species without extracellular CA activity, the direct HCO-3 uptake was investigated using a pH drift technique and the anion exchange inhibitor 4′4′-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS) in a closed system. The result showed that direct HCO-3 transport might occur by an anion exchange mechanism in species Coc. pelagicus and G. oceanica. Of the 13 species investigated, only H. akashiwo did not have the potential for direct uptake or extracellular CA-catalyzed HCO-3 utilization.%为了认识海洋浮游藻类在碳充足和碳受限条件下对水体中溶解无机碳(DIC)的利用方式与可能机理,对13种海洋浮游藻类在不同pH和CO2浓度及不同DIC条件下细胞外碳酸酐酶(CA)的活性进行了分析测定.结果显示:13种藻中,只有Amphidinium carterae和Prorocentrum minimum在碳充足条件下具细胞外CA活性.Melosira sp.、Phaeodactylum tricornutum、Skeletonema costatum、Thalassiosira rotula、Emiliania huxleyi和Pleurochrysis carterae则在碳受限条件下才具细胞外CA活性.Chaetoceros compressus、Glenodinium foliaceum、Coccolithus pelagicus、 Gephrocapsa oceanica和Heterosigma akashiwo即使在碳受限条件下也未检测到细

  16. Alimentación de la anchoveta (Engraulis ringens en el norte de Chile (18°25'-25°40'S en diciembre de 2010

    Directory of Open Access Journals (Sweden)

    Marianela Medina

    2015-03-01

    Full Text Available Se analiza la dieta de Engraulis ringens para determinar posibles diferencias en su comportamiento alimentario por longitud y gradiente latitudinal. Las muestras se obtuvieron entre 18°25'S y 24°40'S durante el crucero de evaluación hidroacústica del reclutamiento de E. ringens, realizado entre el 1 y 20 de diciembre de 2010. El análisis comprendió la determinación de la dieta contenida en un total de 294 estómagos, provenientes de 18 estaciones de muestreo y distribuidos en tres clases de longitud (pre-reclutas, reclutas y adultos. La dieta se describió mediante los métodos numéricos de frecuencia de ocurrencia e índice de importancia relativa, además de la similitud dietaria por longitud y latitud, y especialización trófica. E. ringens registró un amplio espectro trófico, tanto de presas fitoplanctónicas como zooplanctónicas, con una alta predominancia de fitoplancton por sobre zooplancton en 2,5 órdenes de magnitud, por rango de longitud y latitud. Los componentes de mayor importancia relativa en la dieta fueron las diatomeas de los géneros Rhizosolenia y Chaetoceros, y Copepoda dentro del zooplancton. El análisis de la similitud trófica intraespecífica mostró una alta sobreposición entre los grupos de longitud, conformando una "unidad trófica". Mientras que el análisis latitudinal reveló una alta sobreposición trófica con tendencia a formar dos "unidades tróficas", pero sin seguir un patrón definido. Los resultados, confirman el carácter de depredador generalista y oportunista de E. ringens en la zona norte de Chile durante el periodo analizado.

  17. Characterisation of algal organic matter produced by bloom-forming marine and freshwater algae

    KAUST Repository

    Villacorte, Loreen O.

    2015-04-01

    Algal blooms can seriously affect the operation of water treatment processes including low pressure (micro- and ultra-filtration) and high pressure (nanofiltration and reverse osmosis) membranes mainly due to accumulation of algal-derived organic matter (AOM). In this study, the different components of AOM extracted from three common species of bloom-forming algae (Alexandrium tamarense, Chaetoceros affinis and Microcystis sp.) were characterised employing various analytical techniques, such as liquid chromatography - organic carbon detection, fluorescence spectroscopy, fourier transform infrared spectroscopy, alcian blue staining and lectin staining coupled with laser scanning microscopy to indentify its composition and force measurement using atomic force microscopy to measure its stickiness. Batch culture monitoring of the three algal species illustrated varying characteristics in terms of growth pattern, cell concentration and AOM release. The AOM produced by the three algal species comprised mainly biopolymers (e.g., polysaccharides and proteins) but some refractory compounds (e.g., humic-like substances) and other low molecular weight acid and neutral compounds were also found. Biopolymers containing fucose and sulphated functional groups were found in all AOM samples while the presence of other functional groups varied between different species. A large majority (>80%) of the acidic polysaccharide components (in terms of transparent exopolymer particles) were found in the colloidal size range (<0.4μm). The relative stickiness of AOM substantially varied between algal species and that the cohesion between AOM-coated surfaces was much stronger than the adhesion of AOM on AOM-free surfaces. Overall, the composition as well as the physico-chemical characteristics (e.g., stickiness) of AOM will likely dictate the severity of fouling in membrane systems during algal blooms.

  18. Direct Effect of Carbon Dioxide Concentration on Phytoplankton Community Structure in the Ross Sea, Antarctica

    Science.gov (United States)

    Riesselman, C. R.; Tortell, P. D.; Payne, C. D.; Dunbar, R. B.; Ditullio, G. R.

    2006-12-01

    As the largest high-nutrient low-chlorophyll (HNLC) region on the planet, the Southern Ocean plays a critical role in global biogeochemical cycling and climate modulation. Primary productivity and phytoplankton community structure in the waters surrounding Antarctica have demonstrated unique sensitivity to small changes in major and trace element availability and vertical mixing. However, the capacity of changing atmospheric CO2 to restructure Antarctic phytoplankton communities has only recently been proposed. During the austral summer of 2005-2006, the "Controls on Ross Sea Algal Community Structure" (CORSACS) project performed an integrated series of shipboard incubations coupled with polynya water column sampling designed to investigate the interplay of iron, light, and CO2 levels as determinants of primary production and phytoplankton community structure. Results from the CORSACS CO2 manipulation incubation experiment demonstrate substantial shifts in the taxonomic distribution of phytoplankton exposed to an experimental CO2 gradient. Triplicate semi-continuous culture bottles were bubbled with air mixtures containing 100, 370, and 800 ppm CO2, designed to approximate bloom conditions under glacial, modern, and projected future levels of carbon dioxide. At the conclusion of the 18-day incubation, the 100 ppm community was dominated by the small, finely silicified pennate diatom Pseudonitzschia subcurvata, while the abundance of larger, colonial Chaetoceros species increased significantly in the 800 ppm community. These results represent the first evidence that perturbations in atmospheric CO2 have the potential to reorganize phytoplankton community structure in the Southern Ocean, and have implications for both the glacial productivity paradox and the future of polar trophic structure.

  19. Net production and consumption of fluorescent colored dissolved organic matter by natural bacterial assemblages growing on marine phytoplankton exudates.

    Science.gov (United States)

    Romera-Castillo, Cristina; Sarmento, Hugo; Alvarez-Salgado, Xosé Antón; Gasol, Josep M; Marrasé, Celia

    2011-11-01

    An understanding of the distribution of colored dissolved organic matter (CDOM) in the oceans and its role in the global carbon cycle requires a better knowledge of the colored materials produced and consumed by marine phytoplankton and bacteria. In this work, we examined the net uptake and release of CDOM by a natural bacterial community growing on DOM derived from four phytoplankton species cultured under axenic conditions. Fluorescent humic-like substances exuded by phytoplankton (excitation/emission [Ex/Em] wavelength, 310 nm/392 nm; Coble's peak M) were utilized by bacteria in different proportions depending on the phytoplankton species of origin. Furthermore, bacteria produced humic-like substances that fluoresce at an Ex/Em wavelength of 340 nm/440 nm (Coble's peak C). Differences were also observed in the Ex/Em wavelengths of the protein-like materials (Coble's peak T) produced by phytoplankton and bacteria. The induced fluorescent emission of CDOM produced by prokaryotes was an order of magnitude higher than that of CDOM produced by eukaryotes. We have also examined the final compositions of the bacterial communities growing on the exudates, which differed markedly depending on the phytoplankton species of origin. Alteromonas and Roseobacter were dominant during all the incubations on Chaetoceros sp. and Prorocentrum minimum exudates, respectively. Alteromonas was the dominant group growing on Skeletonema costatum exudates during the exponential growth phase, but it was replaced by Roseobacter afterwards. On Micromonas pusilla exudates, Roseobacter was replaced by Bacteroidetes after the exponential growth phase. Our work shows that fluorescence excitation-emission matrices of CDOM can be a helpful tool for the identification of microbial sources of DOM in the marine environment, but further studies are necessary to explore the association of particular bacterial groups with specific fluorophores. PMID:21742918

  20. Parallel detection of harmful algae using reverse transcription polymerase chain reaction labeling coupled with membrane-based DNA array.

    Science.gov (United States)

    Zhang, Chunyun; Chen, Guofu; Ma, Chaoshuai; Wang, Yuanyuan; Zhang, Baoyu; Wang, Guangce

    2014-03-01

    Harmful algal blooms (HABs) are a global problem, which can cause economic loss to aquaculture industry's and pose a potential threat to human health. More attention must be made on the development of effective detection methods for the causative microalgae. The traditional microscopic examination has many disadvantages, such as low efficiency, inaccuracy, and requires specialized skill in identification and especially is incompetent for parallel analysis of several morphologically similar microalgae to species level at one time. This study aimed at exploring the feasibility of using membrane-based DNA array for parallel detection of several microalgae by selecting five microaglae, including Heterosigma akashiwo, Chaetoceros debilis, Skeletonema costatum, Prorocentrum donghaiense, and Nitzschia closterium as test species. Five species-specific (taxonomic) probes were designed from variable regions of the large subunit ribosomal DNA (LSU rDNA) by visualizing the alignment of LSU rDNA of related species. The specificity of the probes was confirmed by dot blot hybridization. The membrane-based DNA array was prepared by spotting the tailed taxonomic probes onto positively charged nylon membrane. Digoxigenin (Dig) labeling of target molecules was performed by multiple PCR/RT-PCR using RNA/DNA mixture of five microalgae as template. The Dig-labeled amplification products were hybridized with the membrane-based DNA array to produce visible hybridization signal indicating the presence of target algae. Detection sensitivity comparison showed that RT-PCR labeling (RPL) coupled with hybridization was tenfold more sensitive than DNA-PCR-labeling-coupled with hybridization. Finally, the effectiveness of RPL coupled with membrane-based DNA array was validated by testing with simulated and natural water samples, respectively. All of these results indicated that RPL coupled with membrane-based DNA array is specific, simple, and sensitive for parallel detection of microalgae which

  1. The dimethylsulphide propionate (DMSP) content in microalgae and its influence on DMS emission: Experimental and modelling study in the Southern North Sea

    Science.gov (United States)

    Gypens, Nathalie; Borges, Alberto V.; Paulet, Sébastien; Parent, Jean-Yves; Lancelot, Christiane

    2013-04-01

    Dimethylsulphide propionate (DMSP) is the precursor of dimethyl sulphide (DMS), a potentially key player in climate regulation. Current knowledge suggests that DMSP synthesis is restricted to some microalgae (mainly Haptophyceae and Dinophyceae) and varies with environmental conditions. Assessing the species-dependence and regulation mechanisms of DMSP microalgal quotas is the first step towards appraising the role of DMS in climate feedback mechanisms. Here we use a combination of laboratory studies and model simulations to determine to which extent the variations of the microalgal DMSP content might affect marine DMS emissions to the atmosphere. The Southern North Sea is chosen as case study, as it is characterized by diatoms/Phaeocystis successions, two phytoplankters known as contrasted DMSP producers. The DMSP:cell content of Phaeocystis globosa and two diatoms, Skeletonema costatum and Chaetoceros socialis, was measured on pure monospecific cultures. While P. globosa and C. socialis showed respectively expected high and low DMSP content, the cell quota measured for S. costatum was unexpectedly high. Based on these results, the sensitivity of the DMS emissions to the variability of the DMSP content of microalgae was estimated by using the MIRO-DMS model. This model couples a DMSP/DMS module to the ecological MIRO model describing carbon and nutrient cycle in the planktonic and benthic system and includes an explicit description of the diatoms/Phaeocystis successions. The model was implemented in a multi-box 0D frame covering the eutrophied Eastern English Channel and Southern North Sea and shows simulations of DMSP and DMS concentrations and DMS emissions in relationship with species succession along a seasonal cycle. Budget calculations allow to estimate the species contribution to DMS emission and highlight the need of further understanding of factors controlling the species-specific synthesis of DMSP.

  2. Seasonal Dynamics of Phytoplankton and Environmental Factors around the Chagwi-do off the West Coast of Jeju Island, Korea

    Science.gov (United States)

    Affan, Abu; Lee, Joon-Baek; Kim, Jun-Teck; Choi, Young-Chan; Kim, Jong-Man; Myoung, Jung-Goo

    2007-06-01

    The dynamics of phytoplankton abundance with seasonal variation in physicochemical conditions were investigated monthly at 10 stations around the Chagwi-do off the west coast of Jeju Island, Korea, including inshore, middle shore, and offshore in the marine ranching area from September 2004 to November 2005. Water temperature varied from 12.1 to 28.9°C (average 18.8°C), and salinity from 28.9 to 34.9 psu (average 33.7 psu). The chlorophyll a concentration was 0.02-2.05 µg L1 (average 0.70 µg L1), and the maximum concentration occurred in the bottom layer in April. A total of 294 phytoplankton species belonging to 10 families was identified: 182 Bacillariophyceae, 52 Dinophyceae, 9 Chlorophyceae, 12 Cryptophyceae, 6 Chrysophyceae, 4 Dictyophyceae, 13 Euglenophyceae, 6 Prymnesiophyceae, 5 Prasinophyceae, and 5 Raphidophyceae. The standing crop was 2.21-48.69x104 cells L1 (average 9.23x 104 cells L1), and the maximum occurred in the bottom layer in April. Diatoms were most abundant throughout the year, followed by dinoflagellates and phytoflagellates. A phytoplankton bloom occurred twice: once in spring, peaking in April, and once in autumn, peaking in November. The spring bloom was represented by four Chaetoceros species and Skeletonema costatum; each contributed 10-20% of the total phytoplankton abundance. The autumn bloom comprised dinoflagellates, diatoms, and phytoflagellates, of which dinoflagellates were predominant. Gymnodinium conicum, Prorocentrum micans, and P. triestinum each contributed over 10% of the total phytoplankton abundance.

  3. Species diversity of phytoplankton communities in the Western Arctic Ocean during summer 2010

    Directory of Open Access Journals (Sweden)

    Gengming Lin

    2013-09-01

    Full Text Available Phytoplankton assemblages in the Arctic Ocean, particularly in the Western Arctic Ocean, remain unclear due to limited long-term ecological investigation caused by the existing harsh environment. In the present study, we characterized summer phytoplankton assemblages in surface water in terms of species composition and spatial distribution in the Western Arctic Ocean in 2010. Phytoplankton samples were collected at 50 stations in the survey area (67.0o–86.1o N, 152.5 o–169.0 o W from 20 July to 30 August 2010 during the CHINARE 2010 cruise aboard the Chinese icebreaker R/V “Xuelong”. Results showed that high species diversity was present in the surface water phytoplankton community. A total of 154 phytoplankton taxa (>5 μm distributed among 67 genera of 10 phyla (or class were identified in the study, which could be divided into four ecological groups, namely Arctic species, Arctic-boreal species, Warm-temperate species and Cosmopolitan species. Phytoplankton diversity exhibited a significant spatial difference with regard to taxonomic composition and abundance during the investigation period. Two phytoplankton assemblages were present in the surface water comprising a shelf community and an open sea community. Average abundance and species richness of the shelf community were 892.6×102 cells/dm3 and 1.81, respectively, and the dominant species were Navicula pelagica, Thalassiosira nordenskioeldii, Chaetoceros diadema, Pseudo-nitzschia seriata, Leptocylindrus danicus, Nitzschia longissima and N. grunowii. A succession from pennate to centric diatoms was evident. The open sea community contained a far lower abundance and species richness (27.7×102 cells/dm3 and 1.28 than the community in the abysmal area and was mainly dominated by Thalassionema nitzschioides. The relationship between the distribution of surface water phytoplankton and several environmental factors were discussed.

  4. Acondicionamiento de reproductores y caracterización gonadal de Tawera gayi (Hupé, 1854 (Bivalva: Veneridae bajo condiciones controladas de cultivo.

    Directory of Open Access Journals (Sweden)

    P.Trigo

    2013-12-01

    Full Text Available El presente estudio describe el acondicionamiento de reproductores bajo sistema controlado del bivalvo Tawera gayi (Hupé, 1854, en el cual se caracterizó el estado de madurez gonadal en base a la presencia de células germinales masculinas y femeninas, estableciéndose su identificación mediante histología a través de microscopia óptica. Como metodología para el acondicionamiento se empleó una bandeja de 15,31 L de volumen útil donde fueron mantenidos 100 ejemplares de T. gayi. El sistema se mantuvo con agua de mar a 29-30 ppm con recambio de agua cada 3 días a temperatura promedio de 16 -18 °C. Con alimentación continua de una mezcla de microalgas de Isochrysis galbana y Chaetoceros muelleri. Los resultados obtenidos, ponen en manifiesto que T. gayi es una especie dioica, sin dimorfismo sexual. Presenta fecundación externa, con un ciclo reproductivo continuo, asincrónico y sin reposo gonadal. Durante las primeras semanas de aclimatación los machos presentaron 100 % de madurez máxima, mientras que las hembras demostraron un 71 % de madurez avanzada y 29% de madurez máxima. Una vez acondicionadas y con alimento continuo, se logró 100% de evacuación parcial en hembras y 50% de evacuación parcial y total en machos, obteniendo desove en cautiverio.

  5. Biogeographical patterns and environmental controls of phytoplankton communities from contrasting hydrographical zones of the Labrador Sea

    Science.gov (United States)

    Fragoso, Glaucia M.; Poulton, Alex J.; Yashayaev, Igor M.; Head, Erica J. H.; Stinchcombe, Mark C.; Purdie, Duncan A.

    2016-02-01

    The Labrador Sea is an important oceanic sink for atmospheric CO2 because of intensive convective mixing during winter and extensive phytoplankton blooms that occur during spring and summer. Therefore, a broad-scale investigation of the responses of phytoplankton community composition to environmental forcing is essential for understanding planktonic food-web organisation and biogeochemical functioning in the Labrador Sea. Here, we investigated the phytoplankton community structure (>4 μm) from near surface blooms (1.2 mg chla m-3) occurred on and near the shelves in May and in offshore waters of the central Labrador Sea in June due to haline- and thermal-stratification, respectively. Sea ice-related (Fragilariopsis cylindrus and F. oceanica) and Arctic diatoms (Fossula arctica, Bacterosira bathyomphala and Thalassiosira hyalina) dominated the relatively cold (<0 °C) and fresh (salinity < 33) waters over the Labrador shelf (e.g., on the southwestern side of the Labrador Sea), where sea-ice melt and Arctic outflow predominates. On the northeastern side of the Labrador Sea, intense blooms of the colonial prymnesiophyte Phaeocystis pouchetii and diatoms, such as Thalassiosira nordenskioeldii, Pseudo-nitzschia granii and Chaetoceros socialis, occurred in the lower nutrient waters (nitrate < 3.6 μM) of the West Greenland Current. The central Labrador Sea bloom occurred later in the season (June) and was dominated by Atlantic diatoms, such as Ephemera planamembranacea and Fragilariopsis atlantica. The data presented here demonstrate that the Labrador Sea spring and early summer blooms are composed of contrasting phytoplankton communities, for which taxonomic segregation appears to be controlled by the physical and biogeochemical characteristics of the dominant water masses.

  6. 秦皇岛西浴场浒苔暴发区浮游植物群落结构特征%Investigation on Phytoplankton Biocoenosis in Enteromorpha Prolifera Area of the West Bathing Beach of Qinhuangdao City

    Institute of Scientific and Technical Information of China (English)

    邹佳君; 朱凌宇; 刘明华

    2016-01-01

    2015年8月12日至28日于秦皇岛西浴场浒苔暴发区共鉴定浮游植物3门20属26种,主要由硅藻和甲藻组成,优势种为尖刺拟菱形藻、中肋骨条藻、旋链角毛藻和浮动弯角藻,与历史资料相比,浮游植物种类没有发生明显变化,调查海域浮游植物平均细胞丰度为40.38×104 cells/L,多样性指数为1.78,均匀度指数为0.38。浒苔等大型藻类对单细胞浮游植物的化感作用导致浮游植物群落多样性与稳定性都出现了显著下降。%A total of 26 taxa which belong to 20 genera of 3 phyla were identified in the west bathing beach of Qinhuangdao city from August 12th to 28th in 2015. The phytoplankton Biocoeno-sis was mainly composed of Bacillariophyta and Dinophyta. The preponderant species were Pseudo-nitzschia pungens, Skeletonema costatum, Chaetoceros curvisetus and Eucompia zoodiacus. No significant change was found in the phytoplankton species compared with the history data. The average cell abundance was 40.38×104 cells/L, and Shannon-wiener diversity index and Pielou's evenness index were 1.78 and 0.38 respectively. Due to the allelopathic effect of E. prolifera, the diversity and stability of phytoplankton Biocoenosis trend to decline.

  7. Toxic effect of a marine bacterium on aquatic organisms and its algicidal substances against Phaeocystis globosa.

    Directory of Open Access Journals (Sweden)

    Qiuchan Yang

    Full Text Available Harmful algal blooms have caused enormous damage to the marine ecosystem and the coastal economy in China. In this paper, a bacterial strain B1, which had strong algicidal activity against Phaeocystis globosa, was isolated from the coastal waters of Zhuhai in China. The strain B1 was identified as Bacillus sp. on the basis of 16S rDNA gene sequence and morphological characteristics. To evaluate the ecological safety of the algicidal substances produced by strain B1, their toxic effects on marine organisms were tested. Results showed that there were no adverse effects observed in the growth of Chlorella vulgaris, Chaetoceros muelleri, and Isochrystis galbana after exposure to the algicidal substances at a concentration of 1.0% (v/v for 96 h. The 48h LC50 values for Brachionus plicatilis, Moina mongolica Daday and Paralichthys olivaceus were 5.7, 9.0 and 12.1% (v/v, respectively. Subsequently, the algicidal substances from strain B1 culture were isolated and purified by silica gel column, Sephadex G-15 column and high-performance liquid chromatography. Based on quadrupole time-of-flight mass spectrometry and PeakView Software, the purified substances were identified as prolyl-methionine and hypoxanthine. Algicidal mechanism indicated that prolyl-methionine and hypoxanthine inhibited the growth of P. globosa by disrupting the antioxidant systems. In the acute toxicity assessment using M. mongolica, 24h LC50 values of prolyl-methionine and hypoxanthine were 7.0 and 13.8 g/L, respectively. The active substances produced by strain B1 can be considered as ecologically and environmentally biological agents for controlling harmful algal blooms.

  8. Feeding strategies of deep-sea sub-Arctic macrofauna of the Faroe-Shetland Channel: Combining natural stable isotopes and enrichment techniques

    Science.gov (United States)

    Gontikaki, E.; Mayor, D. J.; Narayanaswamy, B. E.; Witte, U.

    2011-02-01

    The response of a sub-arctic, deep-sea macrofaunal community to a simulated food sedimentation event was studied by means of a stable isotope "pulse-chase" experiment. A food pulse was simulated by adding 500 mg C m -2 of 13C-labelled diatoms, Chaetoceros radicans, to sediment cores retrieved from 1080 m in the Faroe-Shetland Channel. Carbon uptake by specific macrofaunal groups was quantified after 3 and 6 days of incubation. The carbon uptake of the dominant taxon (Polychaeta) was quantified at the genus-, and where possible, species-level, representing a data resolution that is rare in deep-sea tracer studies. The macrofaunal community reacted rapidly to the diatom addition, with 47% and 70% of the animals illustrating 13C-enrichment after 3 and 6 days, respectively. Approximately 95% of C uptake was located in the upper 2 cm due to the particularly shallow vertical distribution of the macrofaunal community and the nonexistent tracer subduction by burrowing species. Polychaetes of the families Ampharetidae and Cirratulidae were among the most heavily labelled with above background enrichment reaching 1300‰. Approximately 0.8 and 2.0 mg C m -2 were processed by the macrofauna after 3 and 6 days, representing 0.2% and 0.4% of the added carbon, respectively. It was not possible to differentiate sub-surface deposit-feeding polychaetes from predator/scavenger- and omnivorous polychaetes using their natural δ 15N signatures. However, the combination of natural abundance δ 15N data and 13C-labelling experiments proved to be useful for elucidating trophic relations in deep-sea food webs. This study confirms that macrofauna play an active role in the short-term carbon cycling at bathyal depths even at sub-zero temperatures and highlights the need for detailed knowledge of the community structure in understanding carbon processing patterns and early diagenesis of organic matter in marine sediments.

  9. Molecular evidence of the toxic effects of diatom diets on gene expression patterns in copepods.

    Directory of Open Access Journals (Sweden)

    Chiara Lauritano

    Full Text Available BACKGROUND: Diatoms are dominant photosynthetic organisms in the world's oceans and are considered essential in the transfer of energy through marine food chains. However, these unicellular plants at times produce secondary metabolites such as polyunsaturated aldehydes and other products deriving from the oxidation of fatty acids that are collectively termed oxylipins. These cytotoxic compounds are responsible for growth inhibition and teratogenic activity, potentially sabotaging future generations of grazers by inducing poor recruitment in marine organisms such as crustacean copepods. PRINCIPAL FINDINGS: Here we show that two days of feeding on a strong oxylipin-producing diatom (Skeletonema marinoi is sufficient to inhibit a series of genes involved in aldehyde detoxification, apoptosis, cytoskeleton structure and stress response in the copepod Calanus helgolandicus. Of the 18 transcripts analyzed by RT-qPCR at least 50% were strongly down-regulated (aldehyde dehydrogenase 9, 8 and 6, cellular apoptosis susceptibility and inhibitor of apoptosis IAP proteins, heat shock protein 40, alpha- and beta-tubulins compared to animals fed on a weak oxylipin-producing diet (Chaetoceros socialis which showed no changes in gene expression profiles. CONCLUSIONS: Our results provide molecular evidence of the toxic effects of strong oxylipin-producing diatoms on grazers, showing that primary defense systems that should be activated to protect copepods against toxic algae can be inhibited. On the other hand other classical detoxification genes (glutathione S-transferase, superoxide dismutase, catalase, cytochrome P450 were not affected possibly due to short exposure times. Given the importance of diatom blooms in nutrient-rich aquatic environments these results offer a plausible explanation for the inefficient use of a potentially valuable food resource, the spring diatom bloom, by some copepod species.

  10. Importance of bacterivory and preferential selection toward diatoms in larvae of Crepidula fornicata (L.) assessed by a dual stable isotope (13C, 15N) labeling approach

    Science.gov (United States)

    Leroy, Fanny; Riera, Pascal; Jeanthon, Christian; Edmond, Frédérique; Leroux, Cédric; Comtet, Thierry

    2012-05-01

    In Europe, the gastropod Crepidula fornicata is an invasive species characterized by a long reproductive period (from February to November). Thus, its larvae are exposed to variations in available food sources (in terms of quantity and quality). We aimed to investigate if bacteria could contribute to larval food both in presence or absence of phytoplankton, and to compare these results to seasonal variations of bacteria and phytoplankton abundances at a coastal site in the English Channel. First, ingestion of fluorescent beads of 0.5 to 2 μm diameter, showed that larvae were able to ingest particles of typical bacterial size. Then we used a dual stable isotope labeling approach which consisted in labeling a bacterial pelagic community with 15N and a diatom (Chaetoceros gracilis) culture with 13C, and supplying larvae with 15N-labeled bacteria, 13C-labeled diatoms, and both labeled sources. This technique has, to our knowledge, never been applied to invertebrate larvae. After 24 h of experiment, larvae were significantly enriched in all treatments: + 21.5‰ (∆δ13C) when supplied with diatoms, + 1364‰ (∆δ15N) when supplied with bacteria, and + 24‰ (∆δ13C) and + 135‰ (∆δ15N) when supplied with the two mixed sources. These results indicated that bacteria can contribute to the larval nutrition in C. fornicata, even in the presence of phytoplankton. Our results however suggested that larvae of C. fornicata preferentially used diatoms and showed that the supply of free bacteria did not alter the uptake of diatoms. Considering the seasonal variations of bacteria and phytoplankton abundances at the study site, these results suggested that bacteria may constitute a complementary resource for the larvae of C. fornicata when phytoplankton is abundant and may become a substitute resource when phytoplankton is less available. This approach offers promising perspectives to trace food sources and assess nitrogen and carbon fluxes between planktotrophic larvae

  11. The Response of Phytoplankton Size Spectra and Chlorophyll Biomass to Wind-driven Coastal Upwelling off Northern California During the CoOP-WEST Study.

    Science.gov (United States)

    Wilkerson, F. P.; Dugdale, R. C.; Marchi, A.; Hogue, V.; Lassiter, A.; Lew, K.; Lorenzi, A.

    2002-12-01

    During the WEST (Wind Events and Shelf Transport) summer studies of the coastal upwelling region off Bodega Bay, CA, chlorophyll concentrations consistently reached phytoplankton bloom levels following wind driven upwelling events that resulted in high concentrations of pCO2 and nutrients. In most coastal upwelling areas, upwelled nitrate and high rates of new production lie close to the coast in a distinct plume, and their consequences (a band of enhanced chlorophyll) are propagated seaward far beyond the point where upwelled nutrients have been exhausted. Most likely grazing on advected diatoms results in release of regenerated N (ammonium and urea) that is taken up by the small-sized phytoplankton that out-compete diatoms for ammonium and consequently carry coastal new production offshore in the upper layer current system. However in the WEST study area the growing phytoplankton (showing high rates of new production) and productivity are retained on the shelf, and apparently transported alongshore rather than offshore most of the time. The elevated chlorophyll (reaching over 30 μg/l in June 2000) is made up of mostly larger phytoplankton cells with the diatom Chaetoceros spp. dominating during the bloom events. These cells may be grazed or sink and be carried in sub surface currents and re-entrained in the undercurrent, unlike smaller cells that remain in the upper layer. Surface distributions of chlorophyll and phytoplankton size spectra and fluorescence obtained using a CytoSense flow cytometer will be compared between upwelling spring cruises and a non upwelling winter cruise to the CoOP-WEST study site off Bodega Bay, CA.

  12. Feeding strategy of Downs herring larvae (Clupea harengus L.) in the English Channel and North Sea

    Science.gov (United States)

    Denis, Jeremy; Vallet, Carole; Courcot, Lucie; Lefebvre, Valérie; Caboche, Josselin; Antajan, Elvire; Marchal, Paul; Loots, Christophe

    2016-09-01

    This study aims to characterize the larval feeding strategy of the Downs sub-population of North Sea herring (Clupea harengus L.). Diet composition, vacuity rate and prey selectivity of larvae from 8 to 15 mm collected during the International Bottom Trawl Survey (IBTS) - MIK sampling from 2008 to 2013 were assessed by direct observation of their gut contents using Scanning Electron Microscopy (SEM). The high contribution of protists and small zooplanktonic prey observed in the gut contents proved the relevance of SEM to study the diet of first feeding larvae. The relatively low vacuity rate of 45% suggests that food may not be a limiting factor for Downs herring larvae in winter. These larvae appeared to be omnivorous and there was a clear shift in term of prey composition at a size of 13 mm. Smaller larvae (8-12 mm) fed on a higher diversity of small prey, mainly small copepods (Oncaea spp. and Euterpina acutifrons), invertebrate eggs, diatoms (Psammodicthyon panduriforme and Coscinodiscus spp.) and dinoflagellates (Dinophysis acuminate and Prorocentrum micans) whereas bigger larvae (13-15 mm) fed on a lower diversity of larger prey, mainly copepods (Temora longicornis and Paracalanus parvus) and dinoflagellates (Gonyaulax spp.). Downs herring larvae had clear prey preferences as some dinoflagellates (Pyrophacus spp., Gonyaulax spp., P. micans and Porocentrum lima), invertebrate eggs, copepods (Oncaea spp. and nauplii) and diatoms (Thalassiosira curviseriata) were positively selected and other diatoms (Nitzschia spp., Thalassiosira tenera, Thalassiosira spp. and Chaetoceros spp.) and copepods (Pseudocalanus elongatus, T. longicornis and Unidentified calanoid) were negatively selected. We argue that this shift in term of prey preferences occurring at a size of 13 mm constitutes the critical period for Downs herring larvae.

  13. Phytoplankton calcification as an effective mechanism to alleviate cellular calcium poisoning

    Science.gov (United States)

    Müller, M. N.; Ramos, J. Barcelos e.; Schulz, K. G.; Riebesell, U.; Kaźmierczak, J.; Gallo, F.; Mackinder, L.; Li, Y.; Nesterenko, P. N.; Trull, T. W.; Hallegraeff, G. M.

    2015-11-01

    Marine phytoplankton have developed the remarkable ability to tightly regulate the concentration of free calcium ions in the intracellular cytosol at a level of ~ 0.1 μmol L-1 in the presence of seawater Ca2+ concentrations of 10 mmol L-1. The low cytosolic calcium ion concentration is of utmost importance for proper cell signalling function. While the regulatory mechanisms responsible for the tight control of intracellular Ca2+ concentration are not completely understood, phytoplankton taxonomic groups appear to have evolved different strategies, which may affect their ability to cope with changes in seawater Ca2+ concentrations in their environment on geological timescales. For example, the Cretaceous (145 to 66 Ma), an era known for the high abundance of coccolithophores and the production of enormous calcium carbonate deposits, exhibited seawater calcium concentrations up to 4 times present-day levels. We show that calcifying coccolithophore species (Emiliania huxleyi, Gephyrocapsa oceanica and Coccolithus braarudii) are able to maintain their relative fitness (in terms of growth rate and photosynthesis) at simulated Cretaceous seawater calcium concentrations, whereas these rates are severely reduced under these conditions in some non-calcareous phytoplankton species (Chaetoceros sp., Ceratoneis closterium and Heterosigma akashiwo). Most notably, this also applies to a non-calcifying strain of E. huxleyi which displays a calcium sensitivity similar to the non-calcareous species. We hypothesize that the process of calcification in coccolithophores provides an efficient mechanism to alleviate cellular calcium poisoning and thereby offered a potential key evolutionary advantage, responsible for the proliferation of coccolithophores during times of high seawater calcium concentrations. The exact function of calcification and the reason behind the highly ornate physical structures of coccoliths remain elusive.

  14. Biogeochemical and microbial variation across 5500 km of Antarctic surface sediment implicates organic matter as a driver of benthic community structure

    Directory of Open Access Journals (Sweden)

    Deric R Learman

    2016-03-01

    Full Text Available Western Antarctica, one of the fastest warming locations on Earth, is a unique environment that is underexplored with regards to biodiversity. Although pelagic microbial communities in the Southern Ocean and coastal Antarctic waters have been well studied, there are fewer investigations of benthic communities and most have a focused geographic range. We sampled surface sediment from 24 sites across a 5,500 km region of Western Antarctica (covering the Ross Sea to the Weddell Sea to examine relationships between microbial communities and sediment geochemistry. Sequencing of the 16S and 18S rRNA genes showed microbial communities in sediments from the Antarctic Peninsula (AP and Western Antarctica (WA, including the Ross, Amundsen, and Bellingshausen Seas, could be distinguished by correlations with organic matter concentrations and stable isotope fractionation (total organic carbon; TOC, nitrogen, and δ13C. Overall, samples from the AP were higher in nutrient content (TOC, nitrogen, and NH4+ and communities in these samples had higher relative abundances of operational taxonomic units (OTUs classified as the diatom, Chaetoceros, a marine cercozoan and four OTUs classified as Cytophaga or Flavobacteria. As these OTUs were strongly correlated with TOC, the data suggests the diatoms could be a source of organic matter and the Bacteroidetes and cercozoan are grazers that consume the organic matter. Additionally, samples from WA have lower nutrients and were dominated by Thaumarchaeota, which could be related to their known ability to thrive as lithotrophs. This study documents the largest analysis of benthic microbial communities to date in the Southern Ocean, representing almost half the continental shoreline of Antarctica, and documents trophic interactions and coupling of pelagic and benthic communities. Our results indicate potential modifications in carbon sequestration processes related to change in community composition, identifying a

  15. Note on the Occurrence of Phytoplankton and Its Relation with Mass Mortality in the Jakarta Bay, May and November 2004

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    Q. Adnan

    2007-11-01

    Full Text Available There were noted two times (May and November 2004, fish mass mortality occurred in the coast of the Jakarta Bay, killing several species of small and big fishes, crustaceans, eels and molluscs. Phytoplankton blooms in the Jakarta Bay is accelerated by the high input of nutrients, which caused eutropication of the Bay water. Analysis of water sample showed in st 1 (Marina coast showed that phytoplankton abundance was of 2.9 x 106 cells/l-1 , the common diatom species recorded at that time were: Skeletonema costatum, Thalassiosira mala, Bacteriastrum varians, Chaetoceros pseudocurvisetus, Nitzschia sigma, Coscinodiscus radiatus. Of the which: Skeletonema costatum 1.8 x106 cells/l-1 ; in st. 3 Binaria lake was the most a common diatoms species found in the Jakarta Bay. This species frequently bloom, especially after rainfall, causing no harm to marine life, the second diatoms Thalassiosira mala 2.8 x 106 cells/l-1 (st 4 Carnaval coast, during this decade in more often frequencies. The second largest group was represented by four dinoflagellates species: Prorocentrum micans, Protoperidinium sp., Ceratium furca and Gonyaulax sp., and one species dominated of dinoflagellate Prorocentrum micans 2.3 x 106 cells/l-1 (in the Dadap coast. P. micans is also common species of the Jakarta Bay. Hydrological conditions in May and November 2004 are, temperature 32-33 oC, pH 7.76 to 7. 92, Salinity 32‰, Dissolved oxygen 3.88 to 4.26 mg/l, Phosphate 0.10-0.40 ?g-at-P l-1 , Nitrate 0.01 to 0.03 ?g-at-N l-1 . The result suggests that phytoplankton distributes in wider areas than expected and monitoring of its occurrence in Indonesian waters is necessary to prevent harmful effects of such bloom.

  16. Artificial breeding of Chinese sanguin(Hiatula chinensis)%中国紫蛤的人工育苗

    Institute of Scientific and Technical Information of China (English)

    吴进锋; 陈素文; 陈利雄; 朱长波; 奚祝生; 庄娘惜

    2009-01-01

    在繁殖季节对中国紫蛤Hiatuala chinensis亲贝进行营养强化培育可促使性腺在1周内成熟并自然排放精卵.在水温26.0~28.0℃条件下,卵子受精约30 min出现第一极体,1 h后进行第一次分裂发育至2细胞,5 h后发育至囊胚期,12 h后发育至担轮幼虫期,19 h发育至D形幼虫.D形幼虫培育密度控制在1 ind · mL-1,采用不同饵料种类进行培育效果的比较,结果表明,一直投喂小球藻Chlorella vulgaris的效果最差,幼虫发育至第7天陆续死亡;D形幼虫初期投喂金藻Dicrateria zhanjiangensis饵料,从壳顶幼虫期开始混合投喂牟氏角毛藻Chaetoceros muelleri和亚心形扁藻Platymonas subcordiformis,幼虫发育正常,壳长平均增长10 μm · d-1,幼虫培育17 d后开始进入附着变态阶段,从附着变态的稚贝开始,培育50 d,幼贝平均壳长可达4 625 μm,壳长平均增长87.5 μm · d-1.

  17. Biogenic silica dissolution in diatom aggregates: insights from reactive transport modelling

    KAUST Repository

    Moriceau, B

    2014-12-15

    © Inter-Research 2014. Diatom aggregates contribute significantly to the vertical sinking flux of particulate matter in the ocean. These fragile structures form a specific microhabitat for the aggregated cells, but their internal chemical and physical characteristics remain largely unknown. Studies on the impact of aggregation on the Si cycle led to apparent inconsistency. Despite a lower biogenic silica (bSiO2) dissolution rate and diffusion of the silicic acid (dSi) being similar in aggregates and in sea-water, dSi surprisingly accumulates in aggregates. A reaction-diffusion model helps to clarify this incoherence by reconstructing dSi accumulation measured during batch experiments with aggregated and non-aggregated Skeletonema marinoi and Chaetoceros decipiens. The model calculates the effective bSiO2 dissolution rate as opposed to the experimental apparent bSiO2 dissolution rate, which is the results of the effective dissolution of bSiO2 and transport of dSi out of the aggregate. In the model, dSi transport out of the aggregate is modulated by alternatively considering retention (decrease of the dSi diffusion constant) and adsorption (reversible chemical bonds between dSi and the aggregate matrix) processes. Modelled bSiO2 dissolution is modulated by the impact of dSi concentration inside aggregates and diatom viability, as enhanced persistence of metabolically active diatoms has been observed in aggregates. Adsorption better explains dSi accumulation within and outside aggregates, raising the possible importance of dSi travelling within aggregates to the deep sea (potentially representing 20% of the total silica flux). The model indicates that bSiO2 dissolution is effectively decreased in aggregates mainly due to higher diatom viability but also to other parameters discussed herein.

  18. Tritium behavior in an aquatic ecosystem

    International Nuclear Information System (INIS)

    Tritium behavior in aquatic organisms through a model food chain was investigated. In this model food chain, tritium in water reaches bacteria or Japanese killifish via diatoms and brine shrimps. Tritium accumulation in these organisms as organic bound form was expressed as the R value which is defined as the ratio of tritium specific activity in lyophilized organisms (μCi/gH) to that in water (μCi/gH). The maximum R values were 0.5 in diatoms: Chaetoceros gracilis, 0.2 in bacteria: Escherichia coli, 0.5 in brine shrimps: Artemia salina, and 0.32 in Japanese killifish: Oryzias latipes under the growing condition in which tritium accumulation was due to tritium in tritiated water and not tritiated foods. Brine shrimps and Japanese killifish were grown from larve to adult in tritiated sea water and were fed on tritiated foods (model food chain). Their R values were 0.70 and 0.67, respectively. Bacteria, which grew in tritiated water by adding the hydrolysate of tritiated brine shrimps, showed a maximum R value at 0.32. The R values of each organ of Japanese killifish and of DNA and the nucleotides purified from brine shrimps growing in tritiated water with or without tritiated food were measured to estimate the tritium distribution in the body or various molecules of the organisms. These results did not indicate concentration of tritium in specific organs or compounds. The changes of specific activity of tritium in these organisms were measured when they were transferred to non-tritiated water. These retention of tritium was not only different among the tissues but also depended on whether or not the organisms were reared with tritiated foods. (author)

  19. Taxonomic and Environmental Variability in the Elemental Composition and Stoichiometry of Individual Dinoflagellate and Diatom Cells from the NW Mediterranean Sea.

    Directory of Open Access Journals (Sweden)

    Mariona Segura-Noguera

    Full Text Available Here we present, for the first time, the elemental concentration, including C, N and O, of single phytoplankton cells collected from the sea. Plankton elemental concentration and stoichiometry are key variables in phytoplankton ecophysiology and ocean biogeochemistry, and are used to link cells and ecosystems. However, most field studies rely on bulk techniques that overestimate carbon and nitrogen because the samples include organic matter other than plankton organisms. Here we used X-ray microanalysis (XRMA, a technique that, unlike bulk analyses, gives simultaneous quotas of C, N, O, Mg, Si, P, and S, in single-cell organisms that can be collected directly from the sea. We analysed the elemental composition of dinoflagellates and diatoms (largely Chaetoceros spp. collected from different sites of the Catalan coast (NW Mediterranean Sea. As expected, a lower C content is found in our cells compared to historical values of cultured cells. Our results indicate that, except for Si and O in diatoms, the mass of all elements is not a constant fraction of cell volume but rather decreases with increasing cell volume. Also, diatoms are significantly less dense in all the measured elements, except Si, compared to dinoflagellates. The N:P ratio of both groups is higher than the Redfield ratio, as it is the N:P nutrient ratio in deep NW Mediterranean Sea waters (N:P = 20-23. The results suggest that the P requirement is highest for bacterioplankton, followed by dinoflagellates, and lowest for diatoms, giving them a clear ecological advantage in P-limited environments like the Mediterranean Sea. Finally, the P concentration of cells of the same genera but growing under different nutrient conditions was the same, suggesting that the P quota of these cells is at a critical level. Our results indicate that XRMA is an accurate technique to determine single cell elemental quotas and derived conversion factors used to understand and model ocean biogeochemical

  20. Micro-phytoplankton distribution and biomass in and around a channel-based fish farm:implications for sustainable aquaculture

    Institute of Scientific and Technical Information of China (English)

    SADALLY S B; NAZURALLY N; TALEB-HOSSENKHAN N; BHAGOOLI R

    2014-01-01

    Micro-phytoplankton density, genera composition, chlorophyllaconcentration, and physico-chemical pa-rameters were investigated at five stations (S1—near the coast; S2 and S4—at the edges of the aquaculture set-up; S3—in the center of the set-up; and S5—nearby patch of corals) in and around a coastal channel-based fish farm. The highest total micro-phytoplankton density (TPD), including diatoms, dinoflagellates and cyanobacteria, was recorded at S3 ((6.28±2.00)×106 cells/L) followed by S4 ((5.87±2.81)×105 cells/L), S1 ((4.92×105±8.70×104) cells/L), S5 ((3.54×105±5.33×104) cells/L) and S2 ((2.60±1.14)×105cells/L). Chlorophyll a and nutrient concentrations were highest at S3 and were positively correlated with TPD. Among the 35 genera documented in this study,Chaetoceros spp. was the dominant diatom whilePeridinium spp. was the most dominant dinoflagellate. Very low densities of toxic bloom-forming dinoflagellates were encountered during this study. These results suggest that occurrence of non-bloom densities of micro-phytoplankton, possibly due to the natural flushing of the existing lagoonal channel at the aquaculture site, yielded in little environmental impact and can represent an appropriate sustainable approach for future aquaculture de-velopment.

  1. Strong contribution of diatom resting spores to deep-sea carbon transfer in naturally iron-fertilized waters downstream of South Georgia

    Science.gov (United States)

    Rembauville, M.; Manno, C.; Tarling, G. A.; Blain, S.; Salter, I.

    2016-09-01

    Biogeochemical and diatom export fluxes are presented from two bathypelagic sediment trap deployments in the Antarctic Zone of the Southern Ocean. One of the sediment traps was deployed in very productive, naturally iron-fertilized waters downstream of South Georgia (P3, 2000 m) and compared to a deployment in moderately productive waters upstream of the island system (P2, 1500 m). At both sites significant diatom export events occurred in spring (November) and contained mostly empty cells that were associated with low particulate organic carbon (POC) fluxes. A summer export pulse occurred one month later at P2 (end February/March) compared to P3 (end January). Diatom fluxes at P3 were one order of magnitude higher than at P2, a difference mainly attributed to the short and intense export of resting spores from Chaetoceros Hyalochaete and Thalassiosira antarctica species. Aside from these resting spores, diatom export assemblages at both sites were dominated by empty Fragilariopsis kerguelensis frustules. The fraction of diatoms exported as empty frustules was considerably lower at P3 (52%) than P2 (91%). This difference was related to the flux of intact diatom resting spores at P3 and may partially explain the lower Si:C export stoichiometry observed at P3 (1.1) compared to P2 (1.5). Through the enumeration of full diatom frustules and subsequent biomass calculations we estimate that diatom resting spores account for 42% of annual POC flux in the productive waters downstream of South Georgia. At both sites the contribution of diatom vegetative stages to POC fluxes was considerably lower (vector out of the mixed layer. Furthermore, the contribution or resting spores to POC flux in the bathypelagic ocean and sediments suggests they play a particularly important role in sequestering biologically fixed CO2 over climatically relevant timescales.

  2. A Multiple Watershed Approach to Assessing the Effects of Habitat Restoration Actions on Anadromous and Resident Fish Populations, Technical Report 2003-2004.

    Energy Technology Data Exchange (ETDEWEB)

    Marmorek, David

    2004-03-01

    for future habitat restoration actions. Such designs are being developed concurrently with this project by several other groups in the Columbia Basin (RME Workgroup 2003, NMFS 2003, Hillman and Paulsen 2002, Hillman 2003). By addressing questions about habitat restoration and monitoring (in coordination with other related efforts), we hope that this project will catalyze a shift in the Basin's paradigm of habitat restoration, moving from implementation of individual watershed projects towards rigorously designed and monitored, multiwatershed, adaptive management experiments. The project involved three phases of work, which were closely integrated with various related and ongoing efforts in the region: (1) Scoping - We met with a Core Group of habitat experts and managers to scope out a set of testable habitat restoration hypotheses, identify candidate watersheds and recommend participants for a data evaluation workshop. (2) Data Assembly - We contacted over 80 scientists and managers to help evaluate the suitability of each candidate watershed's historical data for assessing the effectiveness of past restoration actions. We eventually settled on the Yakima, Wenatchee, Clearwater, and Salmon subbasins, and began gathering relevant data for these watersheds at a workshop with habitat experts and managers. Data assembly continued for several months after the workshop. (3) Data Analysis and Synthesis - We explored statistical approaches towards retrospectively analyzing the effects of restoration 'treatments' at nested spatial scales across multiple watersheds (Chapters 2-5 of this report). These analyses provided a foundation for identifying existing constraints to testing restoration hypotheses, and opportunities to overcome these constraints through improved experimental designs, monitoring protocols and project selection strategies (Chapters 6 and 7 of this report). Finally, we developed a set of recommendations to improve the design

  3. Phytoplankton dynamics in contrasting early stage North Atlantic spring blooms: composition, succession, and potential drivers

    Directory of Open Access Journals (Sweden)

    C. J. Daniels

    2015-01-01

    Full Text Available The spring bloom is a key annual event in the phenology of pelagic ecosystems, making a major contribution to the oceanic biological carbon pump through the production and export of organic carbon. However, there is little consensus as to the main drivers of spring bloom formation, exacerbated by a lack of in situ observations of the phytoplankton community composition and its evolution during this critical period. We investigated the dynamics of the phytoplankton community structure at two contrasting sites in the Iceland and Norwegian Basins during the early stage (25 March–25 April of the 2012 North Atlantic spring bloom. The plankton composition and characteristics of the initial stages of the bloom were markedly different between the two basins. The Iceland Basin (ICB appeared well mixed to > 400 m, yet surface chlorophyll a (0.27–2.2 mg m–3 and primary production (0.06–0.66 mmol C m–3 d–1 were elevated in the upper 100 m. Although the Norwegian Basin (NWB had a persistently shallower mixed layer (< 100 m, chlorophyll a (0.58–0.93 mg m–3 and primary production (0.08–0.15 mmol C m–3 d–1 remained lower than in the ICB, with picoplankton (> 2 μm dominating chlorophyll a biomass. The ICB phytoplankton composition appeared primarily driven by the physicochemical environment, with periodic events of increased mixing restricting further increases in biomass. In contrast, the NWB phytoplankton community was potentially limited by physicochemical and/or biological factors such as grazing. Diatoms dominated the ICB, with the genus Chaetoceros (1–166 cells mL–1 being succeeded by Pseudo-nitzschia (0.2–210 cells mL–1. However, large diatoms (> 10 μm were virtually absent (< 0.5 cells mL–1 from the NWB, with only small nanno-sized (< 5 μm diatoms present (101–600 cells mL–1. We suggest micro-zooplankton grazing, potentially coupled with the lack of a seed population of bloom forming diatoms, was restricting diatom

  4. Strong contribution of diatom resting spores to deep-sea carbon transfer in naturally iron-fertilized waters downstream of South Georgia

    Science.gov (United States)

    Rembauville, M.; Manno, C.; Tarling, G. A.; Blain, S.; Salter, I.

    2016-09-01

    Biogeochemical and diatom export fluxes are presented from two bathypelagic sediment trap deployments in the Antarctic Zone of the Southern Ocean. One of the sediment traps was deployed in very productive, naturally iron-fertilized waters downstream of South Georgia (P3, 2000 m) and compared to a deployment in moderately productive waters upstream of the island system (P2, 1500 m). At both sites significant diatom export events occurred in spring (November) and contained mostly empty cells that were associated with low particulate organic carbon (POC) fluxes. A summer export pulse occurred one month later at P2 (end February/March) compared to P3 (end January). Diatom fluxes at P3 were one order of magnitude higher than at P2, a difference mainly attributed to the short and intense export of resting spores from Chaetoceros Hyalochaete and Thalassiosira antarctica species. Aside from these resting spores, diatom export assemblages at both sites were dominated by empty Fragilariopsis kerguelensis frustules. The fraction of diatoms exported as empty frustules was considerably lower at P3 (52%) than P2 (91%). This difference was related to the flux of intact diatom resting spores at P3 and may partially explain the lower Si:C export stoichiometry observed at P3 (1.1) compared to P2 (1.5). Through the enumeration of full diatom frustules and subsequent biomass calculations we estimate that diatom resting spores account for 42% of annual POC flux in the productive waters downstream of South Georgia. At both sites the contribution of diatom vegetative stages to POC fluxes was considerably lower (<5%). From these analyses we conclude that resting spore export contributes towards the slightly higher bathypelagic (POC) flux at P3 (40.6 mmol m-2 y-1) compared to P2 (26.4 mmol m-2 y-1). We compared our sediment trap records with previously published diatom assemblage data from the mixed layer and surface sediments (3760 m) around South Georgia. The relative proportion of

  5. An unusual early Holocene diatom event north of the Getz Ice Shelf (Amundsen Sea): Implications for West Antarctic Ice Sheet development

    Science.gov (United States)

    Esper, O.; Gersonde, R.; Hillenbrand, C.; Kuhn, G.; Smith, J.

    2011-12-01

    Modern global change affects not only the polar north but also, and to increasing extent, the southern high latitudes, especially the Antarctic regions covered by the West Antarctic Ice Sheet (WAIS). Consequently, knowledge of the mechanisms controlling past WAIS dynamics and WAIS behaviour at the last deglaciation is critical to predict its development in a future warming world. Geological and palaeobiological information from major drainage areas of the WAIS, like the Amundsen Sea Embayment, shed light on the history of the WAIS glaciers. Sediment records obtained from a deep inner shelf basin north of Getz Ice Shelf document a deglacial warming in three phases. Above a glacial diamicton and a sediment package barren of microfossils that document sediment deposition by grounded ice and below an ice shelf or perennial sea ice cover (possibly fast ice), respectively, a sediment section with diatom assemblages dominated by sea ice taxa indicates ice shelf retreat and seasonal ice-free conditions. This conclusion is supported by diatom-based summer temperature reconstructions. The early retreat was followed by a phase, when exceptional diatom ooze was deposited around 12,500 cal. years B.P. [1]. Microscopical inspection of this ooze revealed excellent preservation of diatom frustules of the species Corethron pennatum together with vegetative Chaetoceros, thus an assemblage usually not preserved in the sedimentary record. Sediments succeeding this section contain diatom assemblages indicating rather constant Holocene cold water conditions with seasonal sea ice. The deposition of the diatom ooze can be related to changes in hydrographic conditions including strong advection of nutrients. However, sediment focussing in the partly steep inner shelf basins cannot be excluded as a factor enhancing the thickness of the ooze deposits. It is not only the presence of the diatom ooze but also the exceptional preservation and the species composition of the diatom assemblage

  6. Does zero-water discharged technology enhance culture performance of pacific white shrimp (Litopenaeus vannamei Boone.)?

    Science.gov (United States)

    Suantika, Gede; Anggraeni, Jayanty; Hasby, Fahri Azhari; Yanuwiarti, Ni Putu Indah

    2014-03-01

    Litopenaeus vannamei or white leg shrimp is an introduced shrimp which has successfully cultured in Indonesia. In Indonesia, L. vannamei is commonly cultured on outdoor/earthen pond that requires renewal of water, less control in term of water quality and disease and attributed to unpredictable yield production. Based on the existing culture condition, a system that enable to minimize water consumption, improve the hygiene of the culture and at the same time maintain a more stable yield production is urgent to be developed by using a zero water discharge system. The system consists of: (a) culture tank - to retain and culture the shrimp; (b) CaCO3 grained - buffering agent and substrate of nitrifying bacteria; (c) aeration line - to provide O2 and homogenize the culture; (d) ancho (feeding) - to control an appropriate feed; (e) nitrifying bacteria adding - to consume ammonium and nitrite then convert it to nitrate, and also control pathogen Vibrio sp.; (f) diatom microalgae (Chaetoceros gracilis) - to uptake nitrate, bacteriostatic agent, feed source, provide O2 and shading. In this study, there were 2 treatments: the static culture (batch) system was set as control (K) (in 70 PL/m2), and culture system with zero-water discharge system which was inoculated by 0.02% v/v 106 CFU/ml of mixed culture nitrifying bacteria and diatom microalgae in 70 PL/m2 (P1). The white leg shrimp used in this experiment was at post larvae (PL) 10 and cultured in a batch system (1 × 1 × 0.5 m3 pond) during 2 months. Several parameters including survival rate, mean body weight, and water quality (salinity, temperature, pH, DO, ammonium, nitrite, and nitrate) were measured. Based on the results, biomass of P1 (237.12 ± 31.11) gram is significantly higher than control (K) (180.80 ± 12.26) gram (Pculture period in all treatments were still in tolerance range of white leg shrimp post larvae, except ammonium concentration in control (K) (2.612 ± 0.56) mg/L which is significantly

  7. Seasonal variations in phytoplankton growth and microzooplankton grazing in a temperate coastal embayment, Korea

    Science.gov (United States)

    Kim, Sunju; Park, Myung Gil; Moon, Changho; Shin, Kyoungsoon; Chang, Man

    2007-01-01

    Microzooplankton grazing on coastal phytoplankton was determined by the dilution method from May 2002 to April 2003 at a fixed site located in the Jinhae Bay, Korea. During the dilution experiments, our study site exhibited a wide range of chlorophyll a concentrations (0.29-127.42 μg l -1), and the species composition of the phytoplankton community changed dramatically over a year, shifting from the predominance of chain-forming diatoms, particularly Chaetoceros spp., Leptocylindrus danicus, Pseudonitzschia pungens, and Skeletonema costatum, between May and September 2002, to a massive bloom of the dinoflagellates, Alexandrium spp. in October 2002, to a dominance of cryptophytes ( Chroomonas sp.) between November 2002 and March 2003, and then again to a prevalence of diatoms toward the end of the experiment. Both nutrients enriched ( μ n) and in situ phytoplankton growth rates ( μ0) showed pronounced seasonal variations, ranging from 0.11 to 2.87 d -1 and from -0.63 to 2.08 d -1, respectively. With regard to both variables, the lowest values were obtained during the fall and winter seasons. The average ratio of μ0/ μ n was 0.96 (SE = 0.08), thereby indicating that phytoplankton growth in the study site was not nutrient-limited. Microzooplankton grazing rates showed the large fluctuations (0-3.86 d -1) over an annual cycle, with non-significant and/or negative grazing frequently (62% of 29 measurements) detected. Relatively high grazing rates did occur frequently at the times during which a large phytoplankton biomass and/or large-sized phytoplankton dominance were observed. Our results contribute to the growing body of evidence suggesting that microzooplankton are important phytoplankton consumers in communities dominated by large phytoplankton, and also bolster the notion that size-based models of food web relationships may be of limited predictive value. The observed large fluctuations in grazing rates over a year, coupled with frequent non-significant and

  8. Consequences of winter upwelling events on biogeochemical and phytoplankton patterns in a western Galician ria (NW Iberian peninsula)

    Science.gov (United States)

    Prego, Ricardo; Guzmán-Zuñiga, Dafne; Varela, Manuel; deCastro, Maite; Gómez-Gesteira, Moncho

    2007-07-01

    during a summer upwelling event (9.9 mol DIN s -1). The taxonomic composition of the phytoplankton community did not change noticeably during LW-up and the summer upwelling, with the same species present and changing only in relative proportions. Diatoms were always the dominant microphytoplankton community, with Pseudonitzschia pungens, Thalassionema nitzschioides and several species of Chaetoceros as characteristic taxons.

  9. Seasonal Variation of Phytoplankton Assemblages Related to Surface Water Mass in the Eastern Part of the South Sea in Korea

    Directory of Open Access Journals (Sweden)

    Pung-Guk Jang

    2013-06-01

    Full Text Available We investigated the seasonal succession of phytoplankton assemblages in the eastern part of the South Sea of Korea in relation to surface water masses. The study areas are under the direct influence of the Tsushima Warm Current (TCW throughout the whole year, with its strength known to be seasonally variable. The region is also influenced by coastal waters (CW driven from the South Sea of Korea and East China Sea, particularly in summer, as indicated by low salinity in the surface water. Nutrient property of the TCW can reveals whether the origin of the TCW is the nutrient-rich Kuroshio Current or the oligotropic Taiwan Warm Current. Surface chlorophyll-a (Chl-a concentrations displayed a large seasonal variation for all stations, with high values found in spring and autumn and low values in summer and winter. At station M (offshore and P (intermediate location between M and R, Chl-a concentrations in October were higher than those in March, when spring bloom normally occurs. This may be related to deeper mixed layer depths in October. Diatoms dominated under conditions of high nutrient supply in which Chaetoceros spp. and Skeletonema costatum-like spp. were abundant. S. costatum-like spp. dominated at stations R (onshore station and P in December when there was greater nutrient supply, especially of phosphate. Flagellates and dinoflagellates dominated at all three stations after diatoms blooms. Dominant species were Scrippsiella trochoid in April and Ceratium furca in October at station R, and Gyrodinium spp. and Gymnodinium spp. at station M during summer, when the effect of the oligotropic Taiwan Warm Current and the oligotropic coastal water from East China Sea were strong. Redundancy analysis showed clear seasonal successions in the phytoplankton community and environmental conditions, in which both principal components 1 and 2 accounted for 69.6% of total variance. Our results suggested that environmental conditions seemed to be determined

  10. Suitable culture conditions and cellular biochemical composition of three diatoms from brackish water%3种半咸水硅藻的适宜培养条件及其细胞生化成分

    Institute of Scientific and Technical Information of China (English)

    曾蓓蓓; 黄旭雄; 危立坤; 刘林林

    2014-01-01

    从上海奉贤一处半咸水池塘分离得到角毛藻(Chaetoceros sp.) SHOU-B98、小环藻(Cyclotella sp.)SHOU-B108和直链藻(Melosira sp.)SHOU-B110.采用单因子实验方法,研究了不同温度、光照强度和盐度对3株硅藻生长的影响,并分析了适宜温度、光照强度和盐度条件下3株硅藻的细胞组成.结果表明:角毛藻SHOU-B98、小环藻SHOU-B108和直链藻SHOU-B110的最适生长温度分别为22.3、20.6和24.7℃;最适光照强度分别为28.0、40.2和69.8 μmol· m-2 ·s-1;最适盐度分别为12.6、6.1和6.7.在适宜培养条件下,角毛藻SHOU-B98、小环藻SHOU-B108和直链藻SHOU-B110的蛋白质含量(占干重)分别为25.88%、21.01%和18.81%;总脂含量分别为10.36%、8.35%和11.34%.小环藻SHOU-B108含有丰富的20∶5n-3(EPA,19.13%)和20∶4n-6(ARA,13.47%).角毛藻SHOU-B98和直链藻SHOU-B110分别含有3.43%和5.90%的22∶ 6n-3(DHA).此3种硅藻富含多不饱和脂肪酸,并且对低盐度有一定的适应性,可作为河口地区特种经济水产动物幼体的饵料微藻.

  11. Diatom and Geochemical Constraints on Pliocene Sea Surface Conditions on the Wilkes Land Margin, East Antarctica

    Science.gov (United States)

    Riesselman, C. R.; Taylor-Silva, B.

    2015-12-01

    The mid-Pliocene is the most recent interval in Earth's history to sustain global temperatures within the range of warming predicted for the 21st century, providing an appealing analog with which to examine the changes we might encounter in the coming century. Diatom-based Southern Ocean sea surface and sea ice reconstructions by the USGS Pliocene Research Interpretations and Synoptic Mapping (PRISM) Group suggest an average +2° summer SST anomaly during the 3.3-3.0 Ma interval relative to modern. Here, we present a reconstruction of Pliocene sea surface conditions from a marine sediment core collected at IODP Site U1361, on the continental rise of the Wilkes Land margin. U1361 biogenic silica concentrations document the alternation of diatom-rich and diatom-poor lithologies; we interpret 8 diatom-rich mudstones within this sequence to record interglacial conditions between 3.8 and 2.8 Ma, across the transition from obliquity control to precession control on East Antarctic ice volumes. This progression also preserves 3 packages of interglacial sediments within the 3.3-3.0 PRISM interval, providing an opportunity for direct comparison to proximal PRISM site Eltanin 50-28. Diatom assemblages in both cores are characterized by Fragilariopsis barronii and Rouxia antarctica, extinct species with an inferred ecological preference for waters south of the polar front. However F. weaveri, an extinct diatom with inferred preference for more northerly waters and moderate abundance in E50-28, has not been identified at U1361. This may indicate that the polar frontal zone migrated across E50-28 (62° 54'S) but remained north of U1361 (64° 25'S) during the mid-Pliocene. This interpretation is bolstered by the low abundance of extant polar front species (e.g., Thalassiosira oliverana, T. lentiginosa) at U1361; these diatoms dominate the E50-28 assemblage. In contrast, the U1361 assemblage includes a number of extant sea ice indicators (F. sublinearis, F. curta, Chaetoceros

  12. The Subpolar North Atlantic Spring Bloom - What Did We Learn from the NAB 2008 Autonomous Experiment?

    Science.gov (United States)

    Perry, M. J.

    2015-12-01

    The subpolar North Atlantic bloom is one of the most remarkable features on the planet, with almost explosive 'greening' of the oceans. Over decades, investigators from countries bordering the North Atlantic have caught snippets of the bloom from research vessels or merchant ships transiting between continents. On 4 April 2008, Eric D'Asaro, Craig Lee, and I began a comprehensive study of the initiation and demise of the spring bloom using 2 types of autonomous platforms - a patch-following Lagrangian mixed-layer float and 4 float-following gliders. The 3 mo autonomous experiment integrated measurements from the float, gliders and ships, observations from satellites, and analyses from models. The diatom-dominated bloom began in mid April when the water column stabilized, not by solar warming, but rather by eddy-driven slumping of horizontal density gradients. The resulting bloom was patchy in both biomass and phytoplankton diversity, despite high, non-limiting concentrations of macronutrients. Magnitudes and relative proportions of net community productivity (NCP; determined from autonomous budgets of O2 and NO3) and net phytoplankton productivity (NPP; computed from ship-based photosynthetic parameters and float-based biomass and light) diverged as the bloom evolved, with higher fractions of particulate organic carbon (POC) consumed within the mixed layer as the bloom aged. Export productivity (EP; derived as the difference between NCP and accumulation rate of POC) was of similar magnitude during the May diatom bloom and the June picophytoplankton bloom. When silicic acid dropped to 1 μM, diatoms aggregated and sank; the deep flux event was dominated by resting spores of Chaetoceros. Although a short-lived event, it was ubiquitously observed by the 4 gliders and ship. An eddy-driven subduction event was likewise observed, indicating transport of otherwise non-sinking POC along isopycnals to depths of > 200 m. These striking export events reinforce the value of a

  13. Community structure and spatial-temporal variation of netz-phytoplankton in the Bering Sea in summer

    Institute of Scientific and Technical Information of China (English)

    WANG Yu; XIANG Peng; YE Youyin; LIN Gengming; YANG Qingliang; LIN Heshan; LIN Mao

    2016-01-01

    Marine biodiversity is changing in response to altered physical environment, subsequent ecological changes as well as anthropogenic disturbances. In this study, phytoplankton samplesin situ collected in the Bering Sea in July of 1999 and 2010 were analyzed to obtain phytoplankton community structure and spatial-temporal variation between the beginning and end of this decade, and the correlation of phytoplankton community dynamics and environmental factors was investigated. A total of 5 divisions, 58 genera and 153 species of phytoplankton belonging to 3 ecological groups were identified. The vast majority of phytoplankton consisted of diatoms accounting for 66.7% of the total species and 95.2% of the total abundance. Considering differentiation in spatial extent and phytoplankton sample types, there were subtle changes in species composition, large altering in abundance and significant variation in spatial distribution between two surveys. The abundance peak area was located at the Bering Strait while sub peak was found at the Bering Sea Basin. The boreal-temperate diatom was the dominant flora, which was subsequently replaced by eurythermal and frigid-water diatom. Phytoplankton community in the Bering Sea was not a simplex uniform community but composed of deep-ocean assemblage and neritic assemblage. The deep-ocean assemblage was located in the northwestern Pacific Ocean and Bering Sea Basin, dominated by boreal-temperate species (Neodenticula seminae,Thalassiothrix longissima,Amphiprora hyperborean,Chaetoceros atlanticus,Thalassiosira trifulta, etc.) and eurychoric species (Thalassionema nitzschioides,Ch. compressus,Rhizosolenia styliformis, etc.), and characterized by low abundance, even inter-species abundance allocations, diverse dominant species and high species diversity. The neritic assemblage was distributed on the continental shelf and slope of Bering Sea and was mainly composed of frigid-water species (Th. nordenskiöldii,Ch. furcellatus,Ch. socialis

  14. Distribution of phytoplankton community in relation to environmental parameters in cage culture area of Sepanggar Bay, Sabah, Malaysia

    Science.gov (United States)

    Sidik, Madihah Jaffar; Rashed-Un-Nabi, Md.; Azharul Hoque, Md.

    2008-11-01

    This paper covers spatial and temporal variation in phytoplankton communities and physico-chemical water properties in the cage culture area of Sepanggar Bay, Sabah, Malaysia based on field measurement conducted during July 2005 to January 2006 to study the spatial and temporal variation in phytoplankton communities and physico-chemical water properties of the bay. Phytoplankton samples and water parameters data were collected from five different stations located inside the bay during Southwest, Interseasonal and Northeast monsoons. Forty phytoplankton genera, representatives of 23 families, were found in the study area with a mean abundance of 1.55 ± 1.19 × 10 6 cells L -1. Most of these genera belong to diatoms (82.17%), Dinoflagellates (17.55%) and cyanobacteria (0.29%). Three genera were found to be dominant (>10%) in phytoplankton abundance and these were Coscinodiscus spp. (36.38%), Chaetoceros spp (17.65%) and Bacteriastrum spp. (10.98%). The most dominant genus was Coscinodiscus spp. which showed high abundance during all monsoons and stations (except Station 3). Among the seven environmental parameters tested in this study, water temperature, pH and suspended sediment concentration were found to be significantly different between monsoons. On the other hand, no significant differences were found between stations for the studied physico-chemical parameters. A clear differences in phytoplankton densities were observed between monsoons and stations with higher mean abundances during interseasonal monsoon (2.40 ± 1.37 × 10 6 cells L -1) and at station five (2.05 ± 0.74 × 10 6 cells L -1), respectively. Conversely, the diversity indices, both Shannon-Wiener (H) and Pielou (J), showed no significant difference throughout stations and monsoons (except (H) for monsoons). Analysis of similarity (ANOSIM) results demonstrated temporal differences in phytoplankton community structure with highly diverse phytoplankton assemblage. Through cluster analysis five

  15. 2009年莱州湾近岸海域浮游植物群落的结构特征%PHYTOPLANKTON COMMUNITY IN THE NEARSHORE WATERS OF LAIZHOU BAY IN 2009

    Institute of Scientific and Technical Information of China (English)

    宁璇璇; 纪灵; 王刚; 夏炳训

    2011-01-01

    根据2009年5、8、10月莱州湾近岸海域的调查数据,对浮游植物的群落结构进行了初步研究.共鉴定浮游植物3门30属58种,主要为温带近岸性和广布性种.其中,硅藻门占总种教的87.9%,以角毛藻属(Chaetoceros)和圆筛藻属(Coscinodiscus)的种类最多;甲藻门占总种数的10.3%,以角藻属(Ceratium)为主.全藻门只有小等刺硅鞭藻(Dictyocha fibula)一种.群落优势种组成存在季节性演替的现象.细胞数量上,硅藻占浮游植物总量的99.8%.经Shannon-Winner 指教、Margalef指教、均匀度指数分析,该海城浮游植物多样性和种丰富度总体较好,群落结构较为稳定.本年度调查共发现赤潮生物38种,建议在夏季加强海域赤潮防范.%Based on the survey of Laizhou Bay in 2009, a preliminary study on the phyto plankton community was carried out. The results showed that 58 phytoplankton species were identified altogether, belonging to 3 phyla with 30 genera, in which 87. 9% were Bacillario phyta and 10. 3% were Dinophyta. In Bacillariophyta, Chaetoceros, and Coscinodiscus were the dominant groups in terms of species number while Ceratium was in Dinophyta. In Chry sophta, only Dictyocha fibula was identified. It was also found that the dominant species changed with different seasons. The average abundance of phytoplankton was 6623. 22×104 cells/m3. In which Bacillariophyta accounted for 99. 8%. Three indices were used to analyze the characteristics of community structure of phytoplankton in the surveyed area. The re sults showed that the diversity and abundance indices were well and the community structure was stable. During the survey, 38 red tide species were identified, and therefore routine mo .nitoring in summer should be strengthened.

  16. Investigation of Net-Phytoplankton Community Structure in Liaodong Bay in Spring of 2009%2009年春季辽东湾网采浮游植物群落结构

    Institute of Scientific and Technical Information of China (English)

    栾莎; 宫相忠; 双秀芝; 高伟; 尹宝树; 邢永泽

    2012-01-01

    The species composition, distribution of cell abundance, community diversity and similarity of net-phytoplankon in Liaodong Bay in spring (May) of 2009 were analyzed. A total of 32 taxa which belong to 23 genera of 3 phyla were identified in the survey area. The majority of species were neritic and cosmopolitan in tem- perate coastal seas, while the minority were oceanic warm water or oceanic species. The phytoplankton community was mainly composed of Bacillariophyta and Dinophyta. The dominant species include Noctiluca scientillans, Proboscia alata, Chaetoceros curvisetus, Coscinodiscus gigas and Pseudo-nitzschia pungens etc. The cell abun- dance of net-phytoplankton was nonuniform and the horizontal distribution showed a decline trend from the coastal areas to the center of the bay. The Shannon-Wiener index and Pielou evenness index were low and the community structure was unsteady. The result of cluster analysis indicated that the phytoplankton community similarity was relatively high.%分析了2009年春季(5月)渤海辽东湾网采浮游植物物种组成,丰度分布,生物多样性指数及群落相似性。春季共鉴定出浮游植物3门23属32种,主要隶属硅藻门和甲藻门,生态类型多为温带近岸型和广布型种类,少部分为暖海性物种或大洋性物种。优势种有夜光藻(Noctilucascientillans)、翼鼻状藻(Probosciaalata)、旋链角毛藻(Chaetoceroscurvisetus)、巨圆筛藻(Coscinodiscusgigas)和尖刺伪菱形藻(Pseudo—nitzsehiapungens)等。浮游植物在各站位的细胞丰度分布不均匀,其平面分布呈现由沿岸海域向海湾中部海域递减的趋势。Shannon—Wiener指数、Pielou指数较低,群落结构简单,稳定性较差。聚类分析结果表明群落之间的相似性较高。

  17. 2013年夏季千里岩岛水产种质资源保护区浮游生物的生态特征%Ecological characteristics of plankton in Qianliyan Island Aquatic Germplasm Reserve in the summer of 2013

    Institute of Scientific and Technical Information of China (English)

    宁璇璇; 夏炳训; 陈权文; 丁琳

    2014-01-01

    Ecological characteristics of plankton such as composition, abundance, dominant species, ecotypes and diversity of Qianliyan Island Aquatic Germplasm Reserve in July of 2013 were analyzed . The results showed that 21 phytoplankton species were identified, belonging to bacillariophyta and dinophyta. The average abundance of phytoplankton was 2.29í104 cells/m3. Chaetoceros was the main dominant species. Most of the ecotypes of phytoplankton were neritic and cosmopolitan in temperate coastal waters. 19 zooplankton species were identified, including copepod, cladocera, amphipoda, sergestidae, chaetognatha and planktonic larvae. The average abundance was 146.90 ind/m3 and biomass was 6.44 mg/m3. Copepod and chaetonatha were main dominant species. The ecotype of these zooplankters was the temperate and neritic species. Comparison with data in 2012 showed that the quantity and abundance of plankton increased while the community tended to stable.%分析了2013年7月千里岩岛水产种质资源保护区海域浮游生物的种类组成、数量分布、优势种类、生态类型与物种多样性等生态特征参数。共发现浮游植物21种,由硅藻和甲藻组成,平均丰度为2.29伊104个/m3,角毛藻为主要优势种类,生态类型以温带近岸性和广温、广布性沿岸种为主。浮游动物19种,包括桡足类、枝角类、端足类、樱虾类、毛颚类和各种浮游幼虫。丰度均值为146.90个/m3,平均生物量为6.44 mg/m3,桡足类和毛颚类为优势类群,生态类型以温带近岸种为主。与2012年同期调查数据相比,浮游生物的种类数量与丰度均有增大,群落结构趋于稳定。

  18. Population dynamics of phytoplankton, heterotrophic bacteria, and viruses during the spring bloom in the western subarctic Pacific

    Science.gov (United States)

    Suzuki, Koji; Kuwata, Akira; Yoshie, Naoki; Shibata, Akira; Kawanobe, Kyoko; Saito, Hiroaki

    2011-05-01

    We characterized the community composition of phytoplankton in the western subarctic Pacific from the pre-bloom to the decline phase of the spring bloom with special reference to decreases in the silicic acid concentration in surface waters as an index for diatom bloom development. Furthermore, responses of heterotrophic bacteria and viruses to the spring bloom were also concomitantly investigated. Under pre-bloom conditions when nutrients were abundant but the surface mixed layer depth was relatively deep, chlorophyll (Chl) a concentrations were consistently low and green algae (chlorophytes and prasinophytes), cryptophytes, and diatoms were predominant in the phytoplankton assemblages as estimated by algal pigment signatures. Together with the shallowing of the mixed layer depth and the decrease in silicic acid concentration, diatoms bloomed remarkably in the Oyashio region, though the magnitude of the bloom in the Kuroshio-Oyashio transition (hereafter Transition) region was relatively small. A total of 77 diatom species were identified, with the bloom-forming diatoms mainly consisting of Thalassiosira, Chaetoceros, and Fragilariopsis species. It has become evident that the carotenoid fucoxanthin can serve as a strong indicator of the diatom carbon biomass during the spring diatom bloom. Differences in the species richness of diatoms among stations generally enabled us to separate the Oyashio bloom stations from the Transition and the Oyashio pre-bloom stations. Relatively high values of the Shannon-Wiener index for the diatom species were also maintained during the Oyashio bloom, indicating that a wide variety of species then shared dominance. In the decline phase of the Oyashio bloom when surface nutrient concentrations decreased, senescent diatom cells increased, as inferred from the levels of chlorophyllide a. Although the cell density of heterotrophic bacteria changed little with the development of the diatom bloom, viral abundance increased toward the end

  19. The marine diatom and diazotroph under future climate: Role of Iron

    Science.gov (United States)

    Li, Xuefeng; Fonseca-batista, Debany; Brouwers, Julie; Roevros, Nathalie; Dehairs, Frank; Chou, Lei

    2016-04-01

    Diatoms constitute a major group of phytoplankton, accounting for one quarter of the world's net primary productivity. Diazotrophs provide the largest input of new nitrogen (N) to the ocean and control the marine N budgets. It has been shown that iron (Fe) can be the limiting factor for diatom growth, in particular, in the HNLC (High Nutrient Low Chlorophyll) regions. This trace element can also govern the development of marine diazotrophs due to the high Fe demand necessary for biological N2 fixation. Iron plays thus an essential role in governing the marine primary productivity and the efficiency of biological carbon pump. Ocean systems are undergoing continuous modifications at varying rates and magnitudes as a result of changing climate. The objectives of our research is to evaluate 1) how climate change (dust deposition, ocean warming and acidification) can affect Fe biogeochemistry and the growth of diatoms and diazotrophs, and 2) the role of Fe in the control of biological N2 fixation under future climate scenarios. Laboratory culture experiments using Chaetoceros socialis were examined at two temperatures (13°C and 18°C) and two CO2 conditions (400 μatm and 800 μatm). The present study demonstrates clearly the influence of ocean acidification on the release of Fe upon dust deposition. It also shows that dust particles could provide a readily utilizable source of Fe and other macronutrients (dissolved phosphate and silicate) for phytoplankton growth. Elevated pCO2 concentrations may have adverse impact on the diatom growth; seawater warming may cause poleward shifts in the biogeographic distribution of diatoms. The impact of Fe on the natural N2 fixation was tested via field incubation experiments using natureal phytoplankton assemblage in the Bay of Biscay and along the Iberian Margin. N2 fixation rates in oligotrophic waters were greatly stimulated through the addition of dissolved Fe compared to the control, demonstrating the limitation of N2 fixation

  20. Impactos da construção do Porto de Suape sobre a comunidade fitoplanctônica no estuário do rio Ipojuca (Pernambuco-Brasil

    Directory of Open Access Journals (Sweden)

    Koening Maria Luise

    2002-01-01

    Full Text Available A construção do Complexo Industrial Portuário de Suape, entre os anos de 1979/84, modificou as características ecológicas da área, sendo os maiores impactos observados no estuário do rio Ipojuca. Visando avaliar a ação desses impactos sobre a comunidade fitoplanctônica através da comparação com estudos realizados antes na área, foram analisadas amostras de plâncton coletadas em uma estação, durante um ciclo de 24 horas, nos períodos chuvoso (agosto/90 e seco (janeiro/91. As amostras foram coletadas pela técnica do fracionamento e com rede de plâncton de 65mm de abertura de malha. Coletas de parâmetros hidrológicos foram realizadas concomitantemente. Foram identificados 97 táxons, destacando-se como espécies muito freqüentes nos períodos chuvoso e seco: Gyrosigma balticum, Oscillatoria princeps, Chaetoceros lorenzianus, Climacosphenia moniligera e Licmophora abbreviata. A densidade fitoplanctônica variou entre 142.000 cels.l-1 a 1.789.000 cels.l-1 predominando a fração do nanofitoplâncton. O maior florescimento ocorreu no período seco, nos horários de maior insolação e maré enchente. A diversidade específica foi alta (> 3 bits.cel.l-1 explicada pela heterogeneidade ambiental. A comunidade fitoplanctônica apresentou mudanças quali-quantitativas após a implantação do Porto. Agora, predominam espécies marinhas litorais, devido à pequena profundidade e elevado hidrodinamismo na área e um decréscimo de 70% na densidade celular, ao contrário do que ocorria antes da construção do Porto, quando foi detectado a maior ocorrência de espécies marinhas planctônicas e maior número de células/litro.

  1. Screening of Fatty Acid Composition of the 13 Microalgae and Their Application in Artificial Breeding of Mitten Crab%13种饵料微藻的脂肪酸组成特点及在河蟹育苗中的应用

    Institute of Scientific and Technical Information of China (English)

    陆开宏; 林霞

    2001-01-01

    1996~1999年间对我国13种习见海、淡水微藻及部分单克隆藻株的高度不饱和脂肪酸(PUFA)组成进行分析.结果表明,在各自适宜培养条件下获得的13种藻类细胞中,硅藻门的三角褐指藻(Phaeodactylum tricornutum)、中肋骨条藻(Skeletonema costatum)、新月菱形藻(Nitzschia closterium)、牟氏角毛藻(Chaetoceros muelleri)和金藻门的绿色巴夫藻(Pavlova viridis)具有较高的EPA含量,占脂肪酸总量的比例分别为19.13%~28.00%、24.62%、27.80%、21.45%和26.65%;而13种藻类细胞中DHA的含量普遍较低,只有绿色巴夫藻、球等鞭金藻(Isochrysis galbana)和等鞭金藻(Isochrysis sp.)存在有意义的DHA含量.蓝藻门的钝顿螺旋藻(Spirulina platensis)、绿藻门的亚心形扁藻(Platymonassubcordiform is)、盐藻(Dunaliella salina)、海水小球藻(Chlorella sp)、淡水蛋白核小球藻(Chlorella pyrenoidosa)和淡水斜生栅藻(Scenedesmus obliquus)没有或仅有很小比例的EPA和DHA.利用高EPA藻种三角褐指藻和DHA含量较高的球等鞭金藻饲育河蟹第一期(ZI)和第二期蚤状幼体(Z2),Z1至Z2的变态率及大眼幼体(M)育成率均明显高于海水小球藻、螺旋藻和鸡蛋黄饲育的对照组.

  2. 4株经济海洋微藻细胞生长的实验室研究%Study on cell growth of 4 kinds of economic marine microalgae in laboratory

    Institute of Scientific and Technical Information of China (English)

    蔡卓平; 李燕璇; 段舜山; 朱红惠

    2013-01-01

    目的 研究角毛藻Chaetoceros sp.、绿色巴夫藻Pavlova viridis、叉鞭金藻Dirateria inornate和杜氏盐藻Dunaliella salina4株经济海洋微藻的细胞生长特性,为微藻在医药学相关行业的开发与应用提供参考依据.方法 采用室内实验方法,以添加f/2营养液的人工海水为培养介质,在植物培养箱中利用三角瓶进行微藻培养试验,测定微藻细胞密度,并计算细胞生长速率.结果 4株经济海洋微藻的细胞生长呈现明显的缓慢期、快速期和平稳期阶段.角毛藻、绿色巴夫藻、叉鞭金藻和杜氏盐藻的最大细胞密度有明显差别,分别为6.71×106、4.916×107、1.225×10 7和4.64×106个/mL.对4株微藻在1~5d、5~9d、9~13 d和13~ 17 d几个时间段的生长速率进行比较分析,结果表明角毛藻、绿色巴夫藻、叉鞭金藻的生长速率在1~5d阶段最大,分别为0.57、0.48、0.55/d;而杜氏盐藻的生长速率在5~9d阶段最大,为0.68/d.结论 实验选用的4株海洋微藻的细胞生长特征存在一定异同,在选育微藻株系开展微藻开发利用研究时应该考虑微藻细胞生长繁殖的差异性.

  3. Phytoplankton variability in relation to some environmental factors in the eastern coast of Suez Gulf, Egypt.

    Science.gov (United States)

    Nassar, Mohamed Z; El-Din, Nihal G Shams; Gharib, Samiha M

    2015-10-01

    Water samples were seasonally collected from 12 stations of the eastern coast of Suez Gulf during autumn of 2012 and winter, spring, and summer of 2013 in order to investigate phytoplankton community structure in relation to some physicochemical parameters. The study area harbored a diversified phytoplankton community (138 species), belonging to 67 genera. Four algal groups were represented and classified as Bacillariophyceae (90 species), Dinophyceae (28 species), Cyanophyceae (16 species), and Chlorophyceae (4 species). The results indicated a relative high occurrence of some species namely.; Pleurotaenium trabecula of green algae; Chaetoceros lorenzianus, Proboscia alata var. gracillima, Pseudosolenia calcar-avis, and Pseudo-nitzschia pungens of diatoms; Trichodesmium erythraeum and Pseudoanabaena limnetica of cyanophytes. Most of other algal species were fairly distributed at the selected stations of the study area. The total abundance of phytoplankton was relatively low (average of 2989 unit/L) in the eastern coast of Suez Gulf, as compared its western coast and the northern part of the Red Sea. The diversity of phytoplankton species was relatively high (2.35-3.82 nats) with an annual average of 3.22 nats in the present study. The results concluded that most of eastern coast of Suez Gulf is still healthy, relatively unpolluted, and oligotrophic area, which is clearly achieved by the low values of dissolved phosphate (0.025-0.3 μM), nitrate (0.18-1.26 μM), and dissolved ammonium (0.81-5.36 μM). Even if the occurrence of potentially harmful algae species was low, the study area should be monitored continuously. The dissolved oxygen ranged between 1.77 and 8.41 mg/L and pH values between 7.6 and 8.41. The multiple regression analysis showed that the dissolved nitrate and pH values were the most effective factors that controlled the seasonal fluctuations of phytoplankton along the eastern coast of Suez Gulf during 2012-2013. PMID:26407862

  4. Ecological characteristics of plankton in Qianliyan Island Aquatic Germplasm Reserve in the summer of 2013%2013年夏季千里岩岛水产种质资源保护区浮游生物的生态特征

    Institute of Scientific and Technical Information of China (English)

    宁璇璇; 夏炳训; 陈权文; 丁琳

    2014-01-01

    分析了2013年7月千里岩岛水产种质资源保护区海域浮游生物的种类组成、数量分布、优势种类、生态类型与物种多样性等生态特征参数。共发现浮游植物21种,由硅藻和甲藻组成,平均丰度为2.29伊104个/m3,角毛藻为主要优势种类,生态类型以温带近岸性和广温、广布性沿岸种为主。浮游动物19种,包括桡足类、枝角类、端足类、樱虾类、毛颚类和各种浮游幼虫。丰度均值为146.90个/m3,平均生物量为6.44 mg/m3,桡足类和毛颚类为优势类群,生态类型以温带近岸种为主。与2012年同期调查数据相比,浮游生物的种类数量与丰度均有增大,群落结构趋于稳定。%Ecological characteristics of plankton such as composition, abundance, dominant species, ecotypes and diversity of Qianliyan Island Aquatic Germplasm Reserve in July of 2013 were analyzed . The results showed that 21 phytoplankton species were identified, belonging to bacillariophyta and dinophyta. The average abundance of phytoplankton was 2.29í104 cells/m3. Chaetoceros was the main dominant species. Most of the ecotypes of phytoplankton were neritic and cosmopolitan in temperate coastal waters. 19 zooplankton species were identified, including copepod, cladocera, amphipoda, sergestidae, chaetognatha and planktonic larvae. The average abundance was 146.90 ind/m3 and biomass was 6.44 mg/m3. Copepod and chaetonatha were main dominant species. The ecotype of these zooplankters was the temperate and neritic species. Comparison with data in 2012 showed that the quantity and abundance of plankton increased while the community tended to stable.

  5. High-resolution observations of plankton spatial distributions correlated with hydrography in the Great South Channel, Georges Bank

    Science.gov (United States)

    Gallager, Scott M.; Davis, Cabell S.; Epstein, Ari W.; Solow, Andy; Beardsley, Robert C.

    During a cruise to Georges Bank in May 1992, the Video Plankton Recorder (VPR) was towyoed while non-invasively obtaining images of the plankton and environmental (CTD) data. Data from an 8 h transect across the Great South Channel (GSC) were analyzed on a continuum of spatial scales from coarse-scale (100 km) to micro-scale (mm). Abundance was determined for 12 taxonomic groups including: invertebrate larvae (ophiopluteus larvae, anthozoa larvae: Cerianthus sp.), hydroids, copepods ( Calanus sp., Pseudocalanus sp.), pteropods ( Limacina retroversa, Clione sp.), ctenophores ( Mnemiopsis sp., Pleurobrachia sp.), larvacea ( Oikopleura sp.), chaetognatha ( Sagitta sp.), and diatom colonies ( Chaetoceros socialis). Species-specific plots of the positions of individual plankton in the water column and plots of the temperature and salinity at which the plankton were observed (temperature-salinity-plankton plots) showed that major taxonomic groups were patchy at coarse scales because of their association with specific water masses of different origin and associated temperature/density discontinuities (pycnocline and fronts). Analysis of the T- S characteristics of water types indicated that diatom colonies and ophiopluteus larvae of echinoderms were transported to GSC in a band of cold water originating on the south flank of Georges Bank. Within this band, diatom colonies formed an intense patch at a front reaching a density of 5 ml -1. Within each water mass, fine-scale (10s of meters) plankton patchiness was associated with regions of vertical stability as indicated by the association of plankton with regions of high gradient Richardson number. Aggregation of plankton at the microscale (<1 m) occurred significantly only for plankton capable of active swimming, suggesting a dynamic interaction between biological and physical variables at this spatial scale. On occasion, veliger larvae of Limacina retroversa were found in spawning patches at concentrations exceeding 600

  6. Comparison of spring-time phytoplankton community composition in two cold years from the western Gulf of Alaska into the southeastern Bering Sea

    Science.gov (United States)

    Stauffer, Beth A.; Goes, Joaquim I.; McKee, Kali T.; do Rosario Gomes, Helga; Stabeno, Phyllis J.

    2014-11-01

    large diatoms of the genera Thalassiosira, Thalassiothrix, and Chaetoceros in 2012. The current study shows that within-regime differences in phytoplankton community composition between years can be almost as great as that between locations with vastly different oceanographic settings. High between- and multi-year variability may combine with a potential overall decline in sea ice in the Bering Sea to produce significant changes in the productive base of the food web with potential cascading effects on higher, economically and ecologically important trophic levels.

  7. Studies on growth rate and grazing mortality rate by microzooplankton of size-fractionated phytoplankton in spring and summer in the Jiaozhou Bay, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Liyong; SUN Jun; LIU Dongyan; YU Zishan

    2005-01-01

    Dilution experiments were performed to examine the growth rate and grazing mortality rate of size-fractionated phytoplankton at three typical stations, inside and outside the bay, in the spring and summer of 2003 in the Jiaozhou Bay, China. In spring, the phytoplankton community structure was similar among the three stations, and was mainly composed of nanophytoplankton, such as, Skeletonema costatum and Cylindrotheca closterium. The structure became significantly different for the three stations in summer, when the dominant species at Stas A, B and C were Chaetoceros curvisetus, Pseudo-nitzschia delicatissima, C. affinis, C. debilis, Coscinodiscus oculus-iridis and Paralia sulcata respectively. Tintinnopsis beroidea and T. tsingtaoensis were the dominant species in spring, whereas the microzooplankton was apparently dominated by Strombidium sp. in summer. Pico- and nanophytoplankton had a relatively greater growth rate than microzooplankton both in spring and summer. The growth rate and grazing mortality rate were 0.18~0.44 and 0.12~1.47 d-1 for the total phytoplankton and 0.20~0.55 and 0.21~0.37 d-1 for nanophytoplankton in spring respectively. In summer,the growth rate and grazing mortality rate were 0.38~0.71 and 0.27~0.60 d-1 for the total phytoplankton and 0.11~1.18 and 0.41~0.72d-1 for nano- and microphytoplankton respectively. The carbon flux consumed by microzooplankton per day was 7.68~39.81 mg/m3 in spring and 12.03~138.22 mg/m3 in summer respectively. Microzooplankton ingested 17.56%~92.19% of the phytoplankton standing stocks and 31.77%~467.88% of the potential primary productivity in spring; in contrast, they ingested 34.60%~83.04% of the phytoplankton standing stocks and 71.28%~98.80% of the potential primary productivity in summer. Pico- and nanophytoplankton appeared to have relatively greater rates of growth and grazing mortality than microphytoplankton during the experimental period. The grazing rate of

  8. Toxicity of benz(a)anthracene and fluoranthene to marine phytoplankton in culture: Does cell size really matter?

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Hiba Ben [UMR 5119 ECOSYM, CNRS-IRD-Universite Montpellier II-Ifremer-Universite Montpellier I, SMEL 2 rue des Chantiers, F-34200 Sete (France); Laboratoire de Cytologie Vegetale et Phytoplanctonologie, Faculte des Sciences de Bizerte, Universite de Carthage, Zarzouna 7021, Bizerte (Tunisia); Leboulanger, Christophe, E-mail: christophe.leboulanger@ird.fr [UMR 5119 ECOSYM, CNRS-IRD-Universite Montpellier II-Ifremer-Universite Montpellier I, SMEL 2 rue des Chantiers, F-34200 Sete (France); Le Floc' h, Emilie [UMS MEDIMEER, CNRS-Universite Montpellier II, SMEL 2 rue des Chantiers F-34200 Sete (France); Hadj Mabrouk, Hassine; Sakka Hlaili, Asma [Laboratoire de Cytologie Vegetale et Phytoplanctonologie, Faculte des Sciences de Bizerte, Universite de Carthage, Zarzouna 7021, Bizerte (Tunisia)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Polycyclic aromatic hydrocarbons (PAHs) in the marine environment are a hazardous chemical legacy. Black-Right-Pointing-Pointer Benz(a)anthracene and fluoranthene are toxic to phytoplankton photosynthesis and growth in culture. Black-Right-Pointing-Pointer Acute (photosynthesis) and chronic (population growth) effects have different thresholds. Black-Right-Pointing-Pointer Toxicity depends on both the species selected as a model and the compound considered. Black-Right-Pointing-Pointer Further study of the size/sensitivity relationship is required to draw more general conclusions. - Abstract: The toxicity of benz(a)anthracene and fluoranthene (polycyclic aromatic hydrocarbons, PAHs) was evaluated on seven species of marine algae in culture belonging to pico-, nano-, and microphytoplankton, exposed to increasing concentrations of up to 2 mg L{sup -1}. The short-term (24 h) toxicity was assessed using chlorophyll a fluorescence transients, linked to photosynthetic parameters. The maximum quantum yield Fv/Fm was lower at the highest concentrations tested and the toxicity thresholds were species-dependent. For acute effects, fluoranthene was more toxic than benz(a)anthracene, with LOECs of 50.6 and 186 {mu}g L{sup -1}, respectively. After 72 h exposure, there was a dose-dependent decrease in cell density, fluoranthene being more toxic than benz(a)anthracene. The population endpoint at 72 h was affected to a greater extent than the photosynthetic endpoint at 24 h. EC50 was evaluated using the Hill model, and species sensitivity was negatively correlated to cell biovolume. The largest species tested, the dinoflagellate Alexandrium catenella, was almost insensitive to either PAH. The population endpoint EC50s for fluoranthene varied from 54 {mu}g L{sup -1} for the picophytoplankton Picochlorum sp. to 418 {mu}g L{sup -1} for the larger diatom Chaetoceros muelleri. The size/sensitivity relationship is proposed as a useful model when

  9. Deep silicon maxima in the stratified oligotrophic Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Y. Crombet

    2011-02-01

    Full Text Available The silicon biogeochemical cycle has been studied in the Mediterranean Sea during late summer/early autumn 1999 and summer 2008. The distribution of nutrients, particulate carbon and silicon, fucoxanthin (Fuco, and total chlorophyll-a (TChl-a were investigated along an eastward gradient of oligotrophy during two cruises (PROSOPE and BOUM encompassing the entire Mediterranean Sea during the stratified period. At both seasons, surface waters were depleted in nutrients and the nutriclines gradually deepened towards the East, the phosphacline being the deepest in the easternmost Levantine basin. Following the nutriclines, parallel deep maxima of biogenic silica (DSM, fucoxanthin (DFM and TChl-a (DCM were evidenced during both seasons with maximal concentrations of 0.45 μmol L−1 for BSi, 0.26 μg L−1 for Fuco, and 1.70 μg L−1 for TChl-a, all measured during summer. Contrary to the DCM which was a persistent feature in the Mediterranean Sea, the DSM and DFMs were observed in discrete areas of the Alboran Sea, the Algero-Provencal basin, the Ionian sea and the Levantine basin, indicating that diatoms were able to grow at depth and dominate the DCM under specific conditions. Diatom assemblages were dominated by Chaetoceros spp., Leptocylindrus spp., Pseudonitzschia spp. and the association between large centric diatoms (Hemiaulus hauckii and Rhizosolenia styliformis and the cyanobacterium Richelia intracellularis was observed at nearly all sites. The diatom's ability to grow at depth is commonly observed in other oligotrophic regions and could play a major role in ecosystem productivity and carbon export to depth. Contrary to the common view that Si and siliceous phytoplankton are not major components of the Mediterranean biogeochemistry, we suggest here that diatoms, by persisting at depth during the stratified period, could contribute to a

  10. 海南西部近岸浮游植物的周年变化及主要关联因素%ANNUAL VARIATION ON PHYTOPLANKTON IN COASTAL WATERS OF WESTERN HAINAN ISLAND AND RELATED AFFECTING FACTORS

    Institute of Scientific and Technical Information of China (English)

    王雨; 林茂; 陈兴群; 林更铭

    2012-01-01

    Annual variation of phytoplankton community in coastal waters at western Hainan Island and its related affecting factors were analyzed based on four cruise surveys of four seasons carried out in 2008 and 2009. A total of 155 species (including 5 forms and 2 varieties) belonging to 74 genera of 4 classes were identified in 165 samples, in which diatoms were predominant in the species composition and the cell abundance. Dinoflagellates contributed the second major group. Cyanobacteria abundance increased in July. The dominant species were Thalassionema nitzschioides, Ba-cillaria paradoxa, Paralia sulcata, Chaetoceros curvisetus, Rhizosolenia styliformis, Trichodesmium spp., Prorocentrum micans, etc. Among them, Thalassionema nitzschioides, Bacillaria paradoxa and Paralia sulcata were dominant in four seasons. The species composition showed a significant seasonal change while phytoplankton cell abundance did not. Phytoplankton species were lower in October than in January, while richer in April and July. The annual average cell abundance of phytoplankton was (6.36±4.75)×l03cells/L (n=165), and the peak cell abundance appeared in October. The phytoplankton abundance of each season reduced from near-shore waters to offshore. Patch distribution of Trichodesmium spp. were obvious in April and July. The diversity index was almost coincident with that of the Pielou evenness index. The high values of both index suggested that the phytoplankton community was in stability and the water quality was healthy in western Hainan Island. Pearson Correlate Analysis of phytoplankton cell abundance with environmental factors indicated that the phytoplankton abundance non-correlated to water temperature, correlated positively to the abio-notrogen in October, and negatively correlated to the salinity in January and to the abio-phosphate in July. The feeding stress from zooplankton directly affected annual variation of the cell abundance of phytoplankton along with influences of

  11. Community structure and its seasonal variation of phytoplankton in adjacent waters of Yangjiang Nuclear Power Plant%阳江核电站邻近水域浮游植物群落结构及其季节变化

    Institute of Scientific and Technical Information of China (English)

    王雨; 林茂; 陈兴群; 林更铭

    2012-01-01

    Based on three cruise surveys in 2009 and 2010, an investigation was carried out on the community structure and its seasonal variation of phytoplankton in the adjacent waters of the nuclear plant being constructed at the second stage in Yangjiang City of Guangdong Province. The water range affected by the thermal effluent and the effects of the nuclear plant on the phytoplankton were predicted. In 78 samples, a total of 125 species (including 2 varieties) were identified , belonging 50 genera of 6 classes, among which, diatoms were predominant in the species composition. Dinoflagellates contributed the second major group. Chromophyta abundance increased sharply in November but not reached the algae bloom threshold of cell abundance. The dominant species were Leptocylindrus danicus, Guinaridia striata, Skeletonema costatum, Pseud-onitzchia pungens, Melosira moniliformis, Phaeocystis globosa, Ceratium furca, and Chaetoceros densus. The species composition and phytoplankton cell abundance showed significant seasonal changes, with different high abundance regions. The seasonal average cell abundance of phytoplankton was (111.8±120.6)×103 cells ? L-1. The overall horizontal distribution of phytoplankton cell abundance had a trend of decreased from nearshore in east to offshore in southwest. The Shannon diversity index was coincident with Pielou evenness index. The low values of the two indices in November suggested that in the survey areas, phytoplankton community was unstable,and water quality was unhealthy. The potential water range affected by the thermal effluent was within 10 km. The seasonal variation of phytoplankton species composition indicated its flexibility to temperature. The occurrence of high abundance of Phaeocystis globosa should be paid attention. The high velocity of flow and the widen water area around Yangjiang Nuclear Power Plant benefited water exchange, and thus, the second-stage project of the Yangjiang Nuclear Power Plant would not make a

  12. Relationship between phytoplankton community succession and environmental factors after Enteromorpha prolifra bloom%浒苔过量繁殖后海区环境因子与浮游植物群落演替规律研究

    Institute of Scientific and Technical Information of China (English)

    宋秀凯; 张秀珍; 刘爱英; 秦华伟; 靳洋; 王文杰; 王建勇

    2011-01-01

    The paper is to present the results from eight surveys about the phytoplankton and water quality conducted near the Haiyang and Rizhao after the bloom of Enteromorpha prolifra from July to September 2008. The results include the identification of 62 phytoplankton species, belonging to 4 phyla, 31 genera. 72.58% of the identified phytoplankton species belong to Bacillariophyceae (20 genera, 45 species), whereas 22.58% to Dinophyta (8 genera, 14 species),with 3.23% being Xanthophyta (2 genera, 2 species), and 1.61% Chrysophyta (1 genera, 1 species). The average density of phytoplankton was 3.52 × l06 ind·m-3, and the greatest percentage, that is, 92.02% is diatom (3.24 × 106 ind·m-3), with dinoflagellate and other species of phytoplankton accounting for 6.70% (2.36 × 105 ind·m-3) and 1.28% (4.5 × 104 ind·m-3), respectively. In addition, the average community abundance, diversity index and homogeneity were 1.266 (0.96- 1.89), 3.012 (2.06- 4.17) and 0.638 (0.43 -0.79), respectively. It was also found that the density of phytoplankton gradually decreased from the inshore area to the offshore area. The phytoplankton community successions of Haiyang and Rizhao were similar. The first dominant species were succeeded from Chaetoceros curvisetus, Ceratium tripos, Chaetoceros affinis,Skeletonema costatum to Thalassionema nitzschioides. The average eutrophication index were 0.115 (0.022 - 0.203 ) and 0.150 (0.059 -0.349) of Haiyang and Rizhao, respectively, and the seawater were poorly eutrophicated. The green tide of Enteromorpha prolifra had an impact on seawater quantity and phytoplankton community. When the nutrient was decreased, the dominant species changed from the diatom to the dinoflagellate. After Enteromorpha prolifra was dead and decomposed, the activated phosphate in the bottom seawater was higher than that in the surface seawater in Haiyang.%为了解浒苔绿潮对周边海域环境影响,在海阳和日照海域进行了8个航次的水

  13. Plankton community structure and diversity in coral reefs area of Sanya Bay, Hainan Province, China%三亚珊瑚礁分布海区浮游生物的群落结构

    Institute of Scientific and Technical Information of China (English)

    柯志新; 黄良民; 谭烨辉; 尹健强

    2011-01-01

    为了更好地了解珊瑚礁区生物群落应对环境变化的生态响应机制,以及浮游生物群落结构与珊瑚礁发展发育的关系,我们于2006年10月26日至11月10日对三亚珊瑚礁保护区9个有珊瑚礁分布的站点进行了浮游生物群落结构的调查.共鉴定出浮游植物种类61属130种(包括变种、变型),其中硅藻门48属101种,甲藻门10属25种,蓝藻门2属3种,金藻门1属1种.硅藻门的角毛藻属(Chaetoceros)种类最多,根管藻属(Rhizosolenia)的种类次之.调查海区浮游植物的细胞丰度范围为348-11,320个/L,平均为3,247个/L.在浮游植物群落中硅藻占绝对优势,平均丰度为3,230个/L,占总密度的99.5%.调查海区共鉴定出浮游动物76种,其中桡足类29种,水母类17种,浮游幼虫10种,毛颚类7种,被囊类6种,浮游腹足类4种,十足类、多毛类和介形类各1种.调查海区浮游动物的密度范围为43-190个/m3,平均为114个/m3.优势类群为桡足类、各类幼虫和毛颚类,平均分别占浮游动物总密度的28.5%,27.7%和13.6%.各站位浮游植物的多样性指数和均匀度平均分别为3.98和0.70,浮游动物的多样性指数和均匀度平均分别为4.37和0.87.鹿回头和大东海海域的浮游植物密度大,而生物多样性指数低.活的造礁石珊瑚种数和覆盖率高的站点的浮游生物多样性也较高.%To better understand mechanisms of plankton community response to environmental change, the plankton community structure and diversity were investigated at nine stations near Sanya city between October 26 and September 10, 2006. A total of 130 phytoplankton taxa belonging to 61 genera and 4 classes, 76 zooplankton species belonging to 9 groups, were identified in the present study. Among the phytoplankton, 101 species in 48 genera belonged to Bacillariophyta, 25 species in 10 genera belonged to Pyrrophyta, 3 species in 2 genera belonged to Cyanophyta, and 1 species belonged to Chrysophyta. The

  14. 高公岛近岸海域浮游植物群落特征%Community characteritics of phytoplankton near Gaogong Island Area

    Institute of Scientific and Technical Information of China (English)

    徐加涛; 吴建新; 阎斌伦; 冯志华; 陈松茂; 李玉

    2012-01-01

    Phytoplankton is the primary producer of the ocean.The variation of its variety and quantity will control the secondary productivity as well as the biomass of fish and other marine animal resources.It plays an important role in the food web of the sea.In August of 2009,the species composition,quantitative distribution,dominant species and community structural characteristics of the phytoplankton were studied at 14 stations near Gaogong Island area(34.62°~34.76°N,119.46°~119.66°E).81 species of 36 genera were identified in the studied water,which belong to 4 phylums including 63 species of 25 genera of Bacillariophyceae,16 species of 9 genera of Pyrroptata,1 species of 1 genera of Cyanophyta and 1 species of 1 genera belong to Chrysophyta.The abundance of phytoplanton varied from 0.458×105 to 3.134×105ind./L with an average value of 1.180×105 ind./L.In this investigation,it was found that diatoms had the most contribution to the main abundance,followed by Pyrroptata.They were the main groups of the phytoplankton.There were 4 species with dominance 0.02 in the zone.among which Cuinardia striata(Stolterfoth) Hasle,Eucampia zoodiacus Ehrenberg,Chaetoceros pseudo-curvisetus Mangin,Chaetoceros tortissimus Gran were the main dominant species,with dominance index of 0.688,0.207,0.142 and 0.103 respectively.The indexes amplitude varied greatly(the species from 19 to 43,the richness 1.064~2.364,the diversity index 2.069~3.428,the evenness index 0.485~0.677),which indicates the instability of community structure.The mean diversity index of phytoplankton was 2.926,the mean richness index was 1.753,the mean evenness index was 0.592.The analysis of correlations showed that water temperature and the evenness index were significantly correlated(P0.05) with correlation coefficient of 0.544,and no significant relation was observed between multivariate analysis of phytoplankton community and environmental factors in the study area.Phytoplankton diversity index

  15. 福建沿海近10a赤潮基本特征分析%Analysis on Characteristics of Red Tide in Fujian Coastal Waters During the Last 10 Years

    Institute of Scientific and Technical Information of China (English)

    李雪丁

    2012-01-01

    There were 161 red tide events collected during the last 10 years from 2001 to 2010 in Fujian coastal waters. Comprehensive analysis was performed using statistical methods and the results indicated the following characteristics of the temporal and spatial distribution of red tide in Fujian coastal waters: ①Outbreaks of red tide often occurred between April and September, and the peak period was in May and June. Most red tide events lasted for 2 to 4 days, and the affected area was below 50 square kilometers. The first outbreak of red tide tended to occur earlier in recent years, and the lasting time became longer.②There were 20 species of organisms causing the red tides in Fujian coastal waters, among which 10 species were Bacillariophyta, 9 species were Dinophyta and 1 species was Protozoa. Prorocentrum donghaiense was the most frequent cause of red tides, followed by Noctiluca scintillans, Skeletonema costatum and Chaetoceros sp.. The species caused red tides obeyed the succession law and there were always new species involved. ③ In terms of spatial distribution, outbreaks of red tides mainly occurred in the coastal waters of Ningde, Fuzhou and Xiamen. The species causing red tides were Prorocentrum donghaiense and Noctiluca in the coastal waters in the north of Pingtan, Fujian Province, Skeletonema costatum and Chaetoceros in the coastal waters in the south of Pingtan, Fujian Province. The comprehensive analysis of the characteristics of red tides during the last 10 years is expected to provide scientific and reasonable basis for the prevention, reduction and forecast of red tides in Fujian coastal waters.%收集整理了自2001-2010年近lOa的福建沿海161起赤潮事件,通过统计的方法综合分析.结果表明福建沿海赤潮在时间和空间上具有以下特征:①时间分布上,赤潮主要发生在4-9月,高发期为5-6月,大部分赤潮的持续时间为2-4d,且发生面积在50km2以下.近年来赤潮初发期的

  16. 5. Rostock bioenergy forum. Proceedings; 5. Rostocker Bioenergieforum. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Within the 5th Rostock bioenergy forum at 2nd and 3rd November, 2011, in Rostock (Federal Republic of Germany) the following lectures were held: (1) International developments in the range of bioenergy (Frank Scholwin); (2) Grassland power Havelland - An analysis of potentials (Sven Schicketanz); (3) MixBioPells: Improvement of the market relevance of alternative biomass mix pellets in Europe (Thomas Zang); (4) Energetic utilization of Paludi biomass (Matthias Ahlhaus); (5) Supply of wood-based bioenergy sources by means of agro-forestry systems (Christian Boehm); (6) Results from experiments with rapidly growing tree species after eighteen years of management in Guelzow (A. Gurgel); (7) Landscape conservation materials - Optimization of the supply of sustainable raw materials by means of implementation of biomass farms (R. Wirkner); (8) Biomass as an energy source - An efficiency comparison from the view of land use (W. Grosse); (9) State of the art of the advancement of stationary fluidized-bed systems with low performance from the view of the engineering design (C. Boehme); (10) Classification and implementation of wood ashes (R. Schraegle); (11) Estimation of the sustainable biomass potential from grasslands of Brandenburg (C. Schleier); (12) Optimization of a regional production of bioalcohol from biogenic residues (M. Buck); (13) Results of the project BioWtL for the use of biogenic residues and wastes in the rapid pyrolysis for the economy of forces (M. Kroeger); (14) Characterization of gaseous primary products of the rapid pyrolysis of biomass (T. Streibel); (15) Vegetable oils as a fuel - DIN 51605 and DIN SPEC 51623 (E. Remmele); (16) Use of rapeseed oils in diesel engines (V. Wichmann); (17) Operation of tractors with rapeseed oil - Experiences and potential of optimization (H.M. Paulsen); (18) Ignition behaviour of different vegetable oils (P. Emberger); (19) Unwanted interactions of biofuel components with engine lubricating oils - Important

  17. Emissions from animal husbandry. Greenhouse gases, environmental assessment, state of the art; Emissionen der Tierhaltung. Treibhausgase, Umweltbewertung, Stand der Technik

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    : Nitrogen and phosphorus flows in pig production (Dennis Otten); (36) Seasonal effect on emissions of ammonia and greenhouse gases in fattening pigs (Zuzana Palkovicova); (37) Greenhouse gas emissions and evaluation of sustainability aspects in dairy farming - data collection on farms, modelling, life cycle assessment (Hans Marten Paulsen); (38) Methodology of a systematic cost-benefit analysis of mitigation strategies for emissions from livestock farming (Regina Roessler); (39) Measuring concept for the quantification of emissions from naturally ventilated housings for dairy cattle (Sabine Schrade); (40) Reduction of ammonia concentration in growing-finishing pigs with FRESTA {sup registered} F Plus (Martin Veit); (41) Measurements in and around intensive livestock farms: Dust, ammonia, greenhouse gases and bioaerosols (Heinz Riedel).

  18. Genomes to Life Project Quarterly Report April 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Heffelfinger, Grant S.; Martino, Anthony; Rintoul, Mark Daniel; Geist, Al; Gorin, Andrey; Xu, Ying; Palenik, Brian

    2006-02-01

    acknowledge the contributions of: Grant Heffelfinger1*, Anthony Martino2, Brian Palenik6, Andrey Gorin3, Ying Xu10,3, Mark Daniel Rintoul1, Al Geist3, Matthew Ennis1, with Pratul Agrawal3, Hashim Al-Hashimi8, Andrea Belgrano12, Mike Brown1, Xin Chen9, Paul Crozier1, PguongAn Dam10, Jean-Loup Faulon2, Damian Gessler12, David Haaland1, Victor Havin4, C.F. Huang5, Tao Jiang9, Howland Jones1, David Jung3, Katherine Kang14, Michael Langston15, Shawn Martin1, Shawn Means1, Vijaya Natarajan4, Roy Nielson5, Frank Olken4, Victor Olman10, Ian Paulsen14, Steve Plimpton1, Andreas Reichsteiner5, Nagiza Samatova3, Arie Shoshani4, Michael Sinclair1, Alex Slepoy1, Shawn Stevens8, Charlie Strauss5, Zhengchang Su10, Ed Thomas1, Jerilyn Timlin1, WimVermaas13, Xiufeng Wan11, HongWei Wu10, Dong Xu11, Grover Yip8, Erik Zuiderweg8 *Author to whom correspondence should be addressed (gsheffe%40sandia.gov) 1. Sandia National Laboratories, Albuquerque, NM 2. Sandia National Laboratories, Livermore, CA 3. Oak Ridge National Laboratory, Oak Ridge, TN 4. Lawrence Berkeley National Laboratory, Berkeley, CA 5. Los Alamos National Laboratory, Los Alamos, NM 6. University of California, San Diego 7. University of Illinois, Urbana/Champaign 8. University of Michigan, Ann Arbor 9. University of California, Riverside 10. University of Georgia, Athens 11. University of Missouri, Columbia 12. National Center for Genome Resources, Santa Fe, NM 13. Arizona State University 14. The Institute for Genomic Research 15. University of Tennessee 5 Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL8500.

  19. Analysis of Inherent Optical Properties in the Occurrence and Declination of a Red Tide%赤潮生消过程中的水体固有光学性质分析

    Institute of Scientific and Technical Information of China (English)

    郝艳玲; 曹文熙; 马毅; 崔廷伟; 张杰

    2011-01-01

    在珠江口海域海洋光学浮标实验中获取一次聚生角毛藻赤潮生消过程的水体光学数据和相应的生化数据.利用该数据,分析了赤潮生消过程中水体光谱吸收和后向散射等光学性质的时间序列变化.研究发现,在赤潮生消过程中,浮游植物色素、非藻类颗粒物以及黄色物质等水体组分吸收变化显著,赤潮爆发期各组分光谱吸收增强并达到最大值,赤潮消亡期各组分光谱吸收降低并至最小值;赤潮爆发期与赤潮发展和消亡期相比,浮游植物的光谱吸收贡献增加约16%,黄色物质的吸收贡献减小约18%,而非藻类颗粒物的吸收贡献变化不大;赤潮爆发期后向散射系数明显增大,日变化幅度大,赤潮发展期和赤潮消亡期后向散射系数较小,赤潮消亡期后向散射系数降至最低;颗粒物后向散射系数与叶绿素a浓度的相关性优于悬浮物浓度.有机颗粒物浓度虽然在总颗粒物浓度中占主导地位,但是颗粒物后向散射与无机颗粒物的相关性更高.%During optical buoy experiments in the Pearl River (Zhujiang) mouth regions, time series of bio-optical data of Chaetoceros socialis red tide is obtained. By using the data, variation of ocean optical properties (absorption and backscattering properties) in the occurrence and declination of red tide is analyzed. Results show that the absorption of various components such as phytoplankton pigments, detritus and colored dissolved organic matter changes dramatically, the absorption of various components increases and reaches maximum values in red tide outbreak period, then the absorption of various components decreases and reaches minimum values in red tide declination period. Compared with red tide development and declination period, contribution of phytoplankton pigment increases by 16%, and that of colored dissolved organic matter decreases by 18% , but that of detritus has little changes for red tide out break

  20. Phytoplankton community and environmental correlates in a coastal upwelling zone along western Taiwan Strait

    Science.gov (United States)

    Wang, Yu; Kang, Jian-hua; Ye, You-yin; Lin, Geng-ming; Yang, Qing-liang; Lin, Mao

    2016-02-01

    Upwelling system in western Taiwan Strait is important for facilitating the fishery production. This study investigated hydro-chemical properties, phytoplankton biomass, phytoplankton species composition, three-dimensional (horizontal, vertical and transect) distribution of phytoplankton abundance, as well as phytoplankton annual variation and the correlation of phytoplankton community with the upwelling of underlying current and nutrients according to samples of Fujian-Guangdong coastal upwelling zone in western Taiwan Strait from August 27 to September 8, 2009. The results manifest that the nutrient-rich cold and high salinity current on the continental shelf of South China Sea upwells to the Fujian-Guangdong coastal waters through Taiwan Bank and the surging strength to surface is weak while strong at 30-m layer. The thermohaline center of coastal upwelling shifts to the east of Dongshan Island and expanded to offshore waters in comparison with previous records. A total of 137 phytoplankton species belonging to 59 genera in 4 phyla are identified excluding the unidentified species. Diatom is the first major group and followed by dinoflagellate. Cyanobacteria mainly composed by three Trichodesmium species account for a certain proportions, while Chrysophyta are only found in offshore waters. The dominant species include Thalassionema nitzschioides, Pseudo-nitzschia pungens, Thalassionema frauenfeldii, Pseudo-nitzschia delicatissima, Rhizosolenia styliformis, Chaetoceros curvisetus, Diplopsalis lenticula and Trichodesmium thiebautii. Phytoplankton community mainly consists of eurythermal and eurytopic species, followed by warm-water species, tropic high-salinity species and oceanic eurythermic species in order. Phytoplankton abundance ranges from 1.00 × 102 ind./L ~ 437.22 × 102 ind./L with an average of 47.36 × 102 ind./L. For vertical distribution, maximum abundance is found at 30 m-depth and the surface comes second. Besides, the abundance below 30 m

  1. Phytoplankton Community Structure in the Tianjin Nearshore Waters during the Summer and Autumn of 2013%2013年春夏季天津近岸海域浮游植物的群落结构

    Institute of Scientific and Technical Information of China (English)

    卞少伟; 孙韧; 梅鹏蔚; 张震; 刘宪斌

    2015-01-01

    -phyta.In June,the Bacillariophyta species Chaetoceros affinis,Coscinodiscus asteromphalus and Coscinodiscus spp. dominated.In August,the prevalent species were the Bacillariophyta species Leptocylindrus danicus,Pseudo-nitzschia pungens and Skeletonema costatum.Phytoplankton abundance ranged from 2.14 ×104 to 836.67 × 104 cells/L in June,with an average of 129.31 ×104 cells/L.In August,the abundance ranged from 6.83 ×104 to 16 042.50 ×104 cells/L with an average of2 461.63 ×104 cells/L.Bacillariophyta accounted for >99%of the to-tal phytoplankton in June and >95%in August at all sampling sites.The distribution of phytoplankton density and Bacillariophyta density were identical.In June,the mean values (range in parentheses)for Shannon-Wiener diver-sity index (H′),Pielou index (J)and Margalef index(d)were 2.87 (0.96-3.69),0.71 (0.28-0.95)and 0.88 (0.60-1.21),respectively.In August,the mean values for H′,J and d were 1.48 (0.01 -3.58),0.33 (0.002-0.86)and 0.91 (0.65 -1.37),respectively.CCA results indicate that water temperature,salinity, dissolved oxygen,nitrite nitrogen and silicates were the leading environmental variables influencing the phytoplank-ton community distribution.%于2013年春季(6月)和夏季(8月)对渤海湾天津近岸海域的浮游植物和环境因子进行了综合调查,共发现浮游植物4门、72种,其中6月39种,8月63种,主要由硅藻和甲藻组成,优势种以硅藻为主,仅有少量的蓝藻和裸藻;6月的优势种是硅藻门的窄隙角毛藻(Chaetoceros affinis)、星脐圆筛藻(Coscinodiscus asteromphalus)及圆筛藻(Coscinodiscus spp.);8月的优势种是硅藻门的丹麦细柱藻(Leptocylindrus danicus)、尖刺拟菱形藻(Pseudo-nitzschia pungens)、中肋骨条藻(Skeletonema costatum)。6月浮游植物细胞密度为2.14×104~836.67×104个/L,平均值为129.31×104个/L;8月浮游植物细胞密度为6.83×104~16042.50×104

  2. Comunidades microplanctônicas no Oceano Atlântico Sul Ocidental: biomassa e distribuição em novembro de 1992 Microplankton communities in the Southwestern Atlantic Ocean: biomass and distribution in November/1992

    Directory of Open Access Journals (Sweden)

    Luciano F. Fernandes

    1999-01-01

    .a/l. Adjacent waters showed low biomass indicating low productivity, with similar average values for Antarctic Water (0.18 J.1g/l and 8ubtropical Water (0.27 J.1g11, where a bloom of Trichodesmium erythraeum was detected. 8ubantarctic waters over the oceanic province around the Patagonian shelf represented a notable exception, with peaks in phytoplankton biomass (up to 2.46 J.1g Chl.a/l. Those areas of enhanced biomass were diatom-dominated; the Prymnesiophyceae Phaeocystis was abundant in some stations. Both fronts presented similar values of chlorophyll-a, indicating that environments with distinctive characteristics could support blooms of the same magnitude. Weakly silicified diatoms (Hemiaulus, Leptocylindrus, Thalassiosira dominated to the north of the BMCZ, while heavily silicified species (Asteromphalus, Chaetoceros aff.neglectus, Fragillariopsis kerguelensis, Proboscia, Pseudonitzschia sp., Rhizosolenia formed the buIk of phytoplankton at the PF, reflecting the different chemical characteristics of the water masses. The diatoms occurring in the PF appear to be recurrent and widely distributed along different longitudes over the Antarctic Circumpolar Current. Ciliates and heterotrophic dinoflagellates were dominant at 8ubtropical Water and to the north ofBMCZ, and seemed to respond quickly to the increasing phytoplankton biomass.

  3. Distribution Features and Relation of Phytoplankton with Environment Factors in the Coastal Water of Guangxi in Summer 2010%2010年夏季广西北部湾沿岸浮游植物分布特征及其与环境因子的相关性

    Institute of Scientific and Technical Information of China (English)

    姜发军; 陈波; 何碧娟; 许铭本; 张荣灿; 雷富

    2012-01-01

    , diatom and dinoflagellate,respectively. Phytoplankton abundance had a lower value in Maowei sea and the coastal zone of Qinzhou port,in addition to the two areas,the quantitative distributions of phytoplankton presented a trend of being higher in the inner bay than in the outer bay. The dominant species were Pseudo - nitzschia pungens ,Skeletonema costatum ,Chaetoceros pseudocurvisetus ,Thalassionema nitzschioides ,Leptocylindrus danicus. P. Pungens and C. Pseudocurvisetus gathered in Fangchenggang sea area, while S. Costatum gathered in the adjacent waters of Beihai. There were no significant rela tionships between phytplankton abundance and temperature,salinity,nitrate,nitrite,ammonia salt and silicate. A positive relationship was found between phytoplankton abundance and phosphate in Beihai sea area and Fangchenggang sea area. Phosphorus was the limiting factor of phytoplankton in the above two sea areas.

  4. 藻类内源产生有色溶解有机物的吸收和三维荧光特性研究%Absorption and Fluorescence Properties of Chromophoric Dissolved Organic Matter Produced by Algae

    Institute of Scientific and Technical Information of China (English)

    彭彤; 陆小兰; 苏荣国; 张栋梅

    2015-01-01

    利用吸收光谱和三维荧光光谱-平行因子分析(EEM-PARAFAC)方法,研究了海洋中常见的四种硅藻、两种甲藻藻液的 CDOM 的光吸收性质和三维荧光特性。吸收光谱测定结果表明在六种藻类生长过程中,旋链角毛藻、三角褐指藻、小新月菱形藻和盐生舟行藻四种硅藻以及东海原甲藻和裸甲藻两种甲藻的α(355)分别增加了64.8%,242.3%,535.1%,903.2%,836.0%和196.4%。表征 CDOM 分子量和类腐殖质组分比例的 Sg 呈下降趋势,分别降低了8.7%,34.6%,39.4%,53.1%,46.7%和35.7%。在三维荧光光谱测定中检测出小新月菱形藻和盐生舟行藻两种硅藻藻滤液的 CDOM 包括三种类腐殖质组分和一种类蛋白质组分:C1(Ex/Em=350(260)nm/450 nm),C2(Ex/Em=260(430)nm/525 nm),C3(Ex/Em=325 nm/400 nm)和 C4(Ex/Em=275 nm/325 nm)。随着藻类的生长,小新月菱形藻和盐生舟行藻藻滤液的 CDOM荧光强度分别增加了8.68,24.9,7.19,39.8倍和2.64,0.07,4.39,12.4倍,经过相关性分析表明各组分的荧光强度与α(355)和 Sg 之间均表现为良好的相关性。综上研究结果表明不论是甲藻还是硅藻,在生长过程中藻类内源所产生的 CDOM 的含量及分子量均表现为上升趋势,且硅藻类相比甲藻增长变化更为明显。在 CDOM 的组成中,类腐殖质成分随藻类生长所占比重同步增大,类蛋白质组分增长缓慢。另外通过该研究可以发现不同种类的藻所产生的 CDOM 的吸收光谱有明显差异,由三维荧光光谱得到的不同荧光组分强度也因藻种不同而不同,说明不同藻种在天然海水中对 CDOM 的贡献有很大区别。%Four kinds of diatom (Chaetoceros curvisetus ,Phaeodactylum tricornutum ,Nitzschia closterium f . minutissima and Navicula halophile )and two kinds of