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Sample records for pseudo-nitzschia multistriata bacillariophyceae

  1. Bloom dynamics of the genus Pseudo-nitzschia (Bacillariophyceae in two coastal bays (NW Mediterranean Sea

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    Sonia Quijano-Scheggia

    2008-09-01

    Full Text Available The spatial and temporal variations in the composition of Pseudo-nitzschia during bloom events from August 2005 to February 2006 were characterised in two bays of the NW Mediterranean Sea (Alfacs and Fangar Bay by means of scanning electron microscopy (SEM. The study provides detailed records of the Pseudo-nitzschia community at the species level and describes its relationship with both the surrounding environmental conditions and biotic factors such as the accompanying phytoplankton community. The size distributions of several species of Pseudo-nitzschia were monitored during the bloom events. These measurements may serve as indicators of the physiological status of the cells. The species observed in the two bays were Pseudo-nitzschia calliantha, P. delicatissima, P. fraudulenta, P. multistriata, and P. pungens. In Alfacs Bay, a mixed species bloom of P. calliantha and P. delicatissima began in late August 2005 and lasted 11 weeks. In Fangar Bay, the Pseudo-nitzschia bloom was limited to the period from early August to late September 2005 and comprised P. calliantha and P. delicatissima. Commonly, the proliferation of Pseudo-nitzschia was mono-specific or was accompanied by other diatoms. Two objectively defined groups were identified by the statistical analysis in Alfacs bay; the first was made up only of winter samples and the second of summer and autumn samples. The first group was defined by a high concentration of NO3¯ and low concentrations of NH4+, conditions associated with a high abundance of P. delicatissima and a low abundance of P. calliantha. The second group expressed the opposite characteristics. A succession of different blooming species of Pseudo-nitzschia lasting months in Alfacs Bay is described.

  2. Pseudo-nitzschia pungens (Bacillariophyceae): A cosmopolitan species?

    DEFF Research Database (Denmark)

    Casteleyn, G; Chepurnov, VA; Leliaert, F

    2007-01-01

    Abstract Genetic, reproductive and morphological variation were studied in 193 global strains of the marine diatom species Pseudo-nitzschia pungens (Grunow ex Cleve) Hasle to assess potential intraspecific variation and biogeographic distribution patterns. Genetic differentiation between allo- an...... Zealand) and the NE Pacific (Washington State). Clade I thus appears to be globally distributed in temperate coastal areas and provides the first strong evidence to date for the global distribution of a biologically, genetically and morphologically defined diatom species.......Abstract Genetic, reproductive and morphological variation were studied in 193 global strains of the marine diatom species Pseudo-nitzschia pungens (Grunow ex Cleve) Hasle to assess potential intraspecific variation and biogeographic distribution patterns. Genetic differentiation between allo...

  3. Identification and characterisation of the dominant Pseudo-nitzschia species (Bacillariophyceae along the NE Spanish coast (Catalonia, NW Mediterranean

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    Sonia Quijano-Scheggia

    2008-06-01

    Full Text Available Potentially toxic species of the genus Pseudo-nitzschia were studied along the Spanish NW Mediterranean coast from January 2005 to May 2006. Observation in electron microscopy revealed the presence of Pseudo-nitzschia brasiliana, P. calliantha, P. delicatissima, P. fraudulenta, P. multistriata and P. pungens. Several strains were isolated from coastal waters and their clonal cultures were compared by combined techniques, including light and electron microscopy and internal transcribed spacer (ITS-1, 5.8S and ITS-2 rDNA sequencing. Cultured isolates were submitted to HPLC analysis of pigments to evaluate the possibility of taxonomic discriminations by means of a simple chemotaxonomic approach. The genus Pseudo-nitzschia showed high cell concentrations during most of the year, but the population initiated a sharp decline at all stations in the period between April and May. P. delicatissima with P. calliantha were found at the northern stations between February and April, and at the southern stations between August and November. P. brasiliana and P. multistriata were only occasionally detected in the southern region. None of the environmental variables considered was significant to explain the observed spatial and temporal distributions of Pseudo-nitzschia species in the area studied. Differences in the growth rate and cell yield of the species indicate that biotic factors may play a role in the observed distributional patterns.

  4. Pseudo-nitzschia simulans sp. nov. (Bacillariophyceae), the first domoic acid producer from Chinese waters

    DEFF Research Database (Denmark)

    Li, Yang; Huang, Chun Xiu; Xu, Guo Shuang

    2017-01-01

    differentiating them from other Pseudo-nitzschia species, represent a new species, Pseudo-nitzschia simulans sp. nov. Morphologically, the taxon belongs to the P. pseudodelicatissima group, cells possessing a central nodule and each stria comprising one row of poroids. The new species is characterized...... by the poroid structure, which typically comprises two sectors, each sector located near opposite margins of the poroid. The production of DA was examined by liquid chromatography tandem mass spectrometry (LC–MS/MS) analyses of cells in stationary growth phase. Domoic acid was detected in one of the five...

  5. A non-toxigenic but morphologically and phylogenetically distinct new species of Pseudo-nitzschia, P. sabit sp. nov. (Bacillariophyceae).

    Science.gov (United States)

    Teng, Sing Tung; Lim, Po Teen; Lim, Hong Chang; Rivera-Vilarelle, María; Quijano-Scheggia, Sonia; Takata, Yoshinobu; Quilliam, Michael A; Wolf, Matthias; Bates, Stephen S; Leaw, Chui Pin

    2015-08-01

    A new species of Pseudo-nitzschia (Bacillariophyceae) is described from plankton samples collected from Port Dickson (Malacca Strait, Malaysia) and Manzanillo Bay (Colima, Mexico). The species possesses a distinctive falcate cell valve, from which they form sickle-like colonies in both environmental samples and cultured strains. Detailed observation of frustules under TEM revealed ultrastructure that closely resembles P. decipiens, yet the new species differs by the valve shape and greater ranges of striae and poroid densities. The species is readily distinguished from the curve-shaped P. subcurvata by the presence of a central interspace. The morphological distinction is further supported by phylogenetic discrimination. We sequenced and analyzed the nuclear ribosomal RNA genes in the LSU and the second internal transcribed spacer, including its secondary structure, to infer the phylogenetic relationship of the new species with its closest relatives. The results revealed a distinct lineage of the new species, forming a sister cluster with its related species, P. decipiens and P. galaxiae, but not with P. subcurvata. We examined the domoic acid (DA) production of five cultured strains from Malaysia by Liquid chromatography-mass spectrometry (LC-MS), but they showed no detectable DA. Here, we present the taxonomic description of the vegetative cells, document the sexual reproduction, and detail the molecular phylogenetics of Pseudo-nitzschia sabit sp. nov. © 2015 Phycological Society of America.

  6. Proliferaciones algales de la diatomea toxigénica Pseudo-Nitzschia (Bacillariophyceae en el Golfo de Nicoya, Costa Rica

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    Maribelle Vargas-Montero

    2004-09-01

    Full Text Available En el mes de noviembre de 2001, se aisló de una marea roja cerca de la Isla San Lucas, las diatomeas Pseudo-Nitzschia pungens f. pungens seguida por Skeletonema costatum, Chaetoceros lorenzianus y en menor concentración Thalassiosira spp. las cuales fueron caracterizadas por microscopía electrónica de rastreo y transmisión, siendo esta la primera vez que se describe la presencia de estas especies produciendo proliferaciones en Costa Rica. Actualmente existe un aumento en el reporte de mareas rojas donde predominan las diatomeas, y los conteos celulares indican el aumento en el número de las especies conocidas como Pseudo-nitzschia pungens f. multiseries. A estas se les atribuye la producción del ácido domóico, un aminoácido de bajo peso molecular. Las intoxicaciones amnésicas por mariscos (IAM que afectan a los humanos, se producen por la ingesta de mariscos contaminados con este ácido. En Costa Rica, hasta la fecha, solo se han reportado casos de intoxicación paralítica por mariscos contaminados por los dinoflagelados Pyrodinium bahamense var. compressum y Gymnodinium catenatum, sin embargo existe la posibilidad de producirse intoxicaciones humanas por la ingesta de mariscos y peces contaminados con toxinas amnésicas las cuales son hidrosolubles y termoestables. Debe entonces considerarse el peligro potencial de aparición de casos de intoxicaciones amnésicas y se sugiere la inclusión de estas especies en los programas de monitoreo permanente para tomar las medidas preventivas de salud públicaWater samples were collected during a red tide event in November 2001, near San Lucas Island (Gulf of Nicoya, Costa Rica. Superficial temperature was 27ºC and water was turbid, with no fetid smell. One sample was treated with negative staining and observed using a transmission electron microscope (TEM; another sample was observed using a scanning electron microscope (SEM. Samples had high concentrations of the diatom Pseudo-Nitzschia

  7. [Algal blooms of the toxigenic diatom Pseudo-Nitzschia (Bacillariophyceae) in the Golfo de Nicoya, Costa Rica].

    Science.gov (United States)

    Vargas-Montero, Maribelle; Freer, Enrique

    2004-09-01

    Water samples were collected during a red tide event in November 2001, near San Lucas Island (Gulf of Nicoya, Costa Rica). Superficial temperature was 27 degrees C and water was turbid, with no fetid smell. One sample was treated with negative staining and observed using a transmission electron microscope (TEM); another sample was observed using a scanning electron microscope (SEM). Samples had high concentrations of the diatom Pseudo-Nitzschia pungensf pungens (characterized by two rows of poroids in the external channel), and lower concentrations of Skeletonema costatum (chains joined by external microtubules) and Chaetoceros lorenzianus (oval apertures and long chains, having setae with distinctive transverse rows and spines). This is the first time that the first species was described producing red tides in Costa Rica. However, reports about red tides with high concentration of species like P. pungens (variety multiseries) are increasing. These species have been related to the production of domoic acid, a low molecular weight amino acid which in humans can cause amnesic intoxications with seafood. Previously, Costa Rican reports of toxic accidents only referred to seafood contaminated with Pyrodinium bahamense var. compressum and Gymnodinium catenatum dinoflagellates. The increase in the number of Pseudo-Nitzschia causing harmful algae blooms is of interest for scientists around the world and must be documented. Similarly, some Chaetoceros species have been reported to be harmful to fish. We strongly recommend the establishment of a permanent surveillance program monitoring the presence of these species new at Costa Rican Pacific coast. Since the amnesic toxin is soluble in water and heat-resistant, we want to stress the possibility of having human cases of amnesic intoxication.

  8. Análisis morfológico y toxicológico de cultivos de Pseudo-nitzschia pungens var. pungens (Bacillariophyceae Morphological and toxicological analysis of cultures of Pseudo-nitzschia pungens var. pungens (Bacillariophyceae

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    Eugenia A. Sar

    2006-12-01

    Full Text Available En el marco de un proyecto de monitoreo de especies de diatomeas nocivas llevado a cabo en el área norte del Golfo San Matías (Provincia de Río Negro, Argentina hemos encontrado a Pseudo-nitzschia pungens (Grunow ex. P.T. Cleve Hasle var. pungens y establecido cultivos monoclonales de esta variedad. Las cepas aisladas a partir de muestras tomadas con red, provenientes de Las Grutas y Piedras Coloradas (Golfo San Matías, fueron cultivadas en medio F/2 con adición de silicatos, y mantenidas a 20 ºC con luz continua, blanca, fría. Los cultivos fueron analizados mediante Cromatografía Líquida de Alta Resolución (HPLC para determinar si la variedad aislada era productora de ácido domoico (DA en el área bajo estudio. Material procedente de campo y de cultivo fue estudiado con microscopios óptico y electrónico de barrido. Una comparación con los taxa más allegados, P . pungens var. cingulata Villac y P . multiseries (Hasle Hasle, y datos sobre la morfología fina del material procedente de los cultivos, son presentados y discutidos. A pesar de que P . pungens var. pungens ha sido reportada como productora de ácido domoico, los resultados del análisis para detección de las toxinas fueron negativos para las cultivos chequeados.In the framework of a project of monitoring of harmful diatom species carried out in the Northern area of the Golfo San Matías (Provincia de Río Negro, Argentina we found and established cultures of Pseudo-nitzschia pungens (Grunow ex. P.T. Cleve Hasle var. pungens . The strains isolated from net phytoplankton samples obtained in Las Grutas and Piedras Coloradas, (Golfo San Matías were cultured in F/2 medium, with silica added, and maintained at 20 ºC, under continuous light supplied by cool-white fluorescent tubes. Cultures were essayed for domoic acid (DA by High Performance Liquid Chromatography (HPLC. Materials from field and cultures were studied with light and scanning electron microscopy. Comparison

  9. Identification of the meiotic toolkit in diatoms and exploration of meiosis-specific SPO11 and RAD51 homologs in the sexual species Pseudo-nitzschia multistriata and Seminavis robusta.

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    Patil, Shrikant; Moeys, Sara; von Dassow, Peter; Huysman, Marie J J; Mapleson, Daniel; De Veylder, Lieven; Sanges, Remo; Vyverman, Wim; Montresor, Marina; Ferrante, Maria Immacolata

    2015-11-14

    Sexual reproduction is an obligate phase in the life cycle of most eukaryotes. Meiosis varies among organisms, which is reflected by the variability of the gene set associated to the process. Diatoms are unicellular organisms that belong to the stramenopile clade and have unique life cycles that can include a sexual phase. The exploration of five diatom genomes and one diatom transcriptome led to the identification of 42 genes potentially involved in meiosis. While these include the majority of known meiosis-related genes, several meiosis-specific genes, including DMC1, could not be identified. Furthermore, phylogenetic analyses supported gene identification and revealed ancestral loss and recent expansion in the RAD51 family in diatoms. The two sexual species Pseudo-nitzschia multistriata and Seminavis robusta were used to explore the expression of meiosis-related genes: RAD21, SPO11-2, RAD51-A, RAD51-B and RAD51-C were upregulated during meiosis, whereas other paralogs in these families showed no differential expression patterns, suggesting that they may play a role during vegetative divisions. An almost identical toolkit is shared among Pseudo-nitzschia multiseries and Fragilariopsis cylindrus, as well as two species for which sex has not been observed, Phaeodactylum tricornutum and Thalassiosira pseudonana, suggesting that these two may retain a facultative sexual phase. Our results reveal the conserved meiotic toolkit in six diatom species and indicate that Stramenopiles share major modifications of canonical meiosis processes ancestral to eukaryotes, with important divergences in each Kingdom.

  10. Quantitative PCR Coupled with Melt Curve Analysis for Detection of Selected Pseudo-nitzschia spp. (Bacillariophyceae) from the Northwestern Mediterranean Sea▿

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    Andree, Karl B.; Fernández-Tejedor, Margarita; Elandaloussi, Laurence M.; Quijano-Scheggia, Sonia; Sampedro, Nagore; Garcés, Esther; Camp, Jordi; Diogène, Jorge

    2011-01-01

    The frequency and intensity of Pseudo-nitzschia spp. blooms along the coast of Catalonia have been increasing over the past 20 years. As species from this genus that are documented as toxigenic have been found in local waters, with both toxic and nontoxic species cooccurring in the same bloom, there is a need to develop management tools for discriminating the difference. Currently, differentiation of toxic and nontoxic species requires time-consuming electron microscopy to distinguish taxonomic features that would allow identification as to species, and cryptic species can still remain misidentified. In this study, cells of Pseudo-nitzschia from clonal cultures isolated from seawater were characterized to their species identity using scanning electron microscopy, and subsamples of each culture were used to create an internal transcribed spacer 1 (ITS-1), 5.8S, and ITS-2 ribosomal DNA database for development of species-specific quantitative PCR (qPCR) assays. Once developed, these qPCR assays were applied to field samples collected over a 2-year period in Alfaques Bay in the northwestern Mediterranean Sea to evaluate the possibility of a comprehensive surveillance for all Pseudo-nitzschia spp. using molecular methods to supplement optical microscopy, which can discern taxonomy only to the genus level within this taxon. Total Pseudo-nitzschia cell density was determined by optical microscopy from water samples collected weekly and compared to results obtained from the sum of eight Pseudo-nitzschia species-specific qPCR assays using duplicate samples. Species-specific qPCR followed by melt curve analysis allowed differentiation of amplicons and identification of false positives, and results correlated well with the total Pseudo-nitzschia cell counts from optical microscopy. PMID:21193668

  11. Identification of a domoic acid-producing pseudo-Nitzschia species (Bacillariophyceae) in the Dutch Wadden sea with electron microscopy and molecular probes

    NARCIS (Netherlands)

    Vrieling, Engel G.; Koeman, Reinoud P.T.; Scholin, Christopher A.; Scheerman, Paul; Peperzak, Louis; Veenhuis, Marten; Gieskes, Winfried W.C.

    1996-01-01

    Biological monitoring in the Dutch Wadden Sea between November 1993 and July 1994 revealed Pseudo-nitzschia-like pennate chain-forming diatom species with cell numbers ranging from 10^2 to 10^5 per litre. Cultured isolates and field samples were examined by electron microscopy, which revealed the

  12. Effects of Organic and Inorganic Nitrogen on the Growth and Production of Domoic Acid by Pseudo-nitzschia multiseries and P. australis (Bacillariophyceae in Culture

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    Véronique Martin-Jézéquel

    2015-11-01

    Full Text Available Over the last century, human activities have altered the global nitrogen cycle, and anthropogenic inputs of both inorganic and organic nitrogen species have increased around the world, causing significant changes to the functioning of aquatic ecosystems. The increasing frequency of Pseudo-nitzschia spp. in estuarine and coastal waters reinforces the need to understand better the environmental control of its growth and domoic acid (DA production. Here, we document Pseudo-nitzschia spp. growth and toxicity on a large set of inorganic and organic nitrogen (nitrate, ammonium, urea, glutamate, glutamine, arginine and taurine. Our study focused on two species isolated from European coastal waters: P. multiseries CCL70 and P. australis PNC1. The nitrogen sources induced broad differences between the two species with respect to growth rate, biomass and cellular DA, but no specific variation could be attributed to any of the inorganic or organic nitrogen substrates. Enrichment with ammonium resulted in an enhanced growth rate and cell yield, whereas glutamate did not support the growth of P. multiseries. Arginine, glutamine and taurine enabled good growth of P. australis, but without toxin production. The highest DA content was produced when P. multiseries grew with urea and P. australis grew with glutamate. For both species, growth rate was not correlated with DA content but more toxin was produced when the nitrogen source could not sustain a high biomass. A significant negative correlation was found between cell biomass and DA content in P. australis. This study shows that Pseudo-nitzschia can readily utilize organic nitrogen in the form of amino acids, and confirms that both inorganic and organic nitrogen affect growth and DA production. Our results contribute to our understanding of the ecophysiology of Pseudo-nitzschia spp. and may help to predict toxic events in the natural environment.

  13. Proliferaciones de Pseudo-nitzschia spp. (Bacillariophyceae y otras especies del microplancton en la Bahía de Mazatlán, México

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    Samuel Gómez-Aguirre

    2004-09-01

    Full Text Available Observaciones previas sobre el microplancton de la Bahía de Mazatlán, en el otoño de 1996, revelaron la existencia de altas densidades de Pseudo-nitzschia spp. Este mismo fenómeno se encontró en noviembre 1998 y un mes después se había desplazado al sur de la Bahía de Mazatlán, mientras que por esas mismas fechas, en California, EUA, se registraban accidentes de envenenamiento de mamíferos marinos, accidentes que en el noroeste de México se aprecian entre enero y marzo. Mensualmente se recolectaron muestras de agua superficial (Observations on microplankton in the autumn of 1996 revealed the existence of high densities of Pseudo-nitzschia spp. A similar phenomenon was found in November 1998 and November 1999 and a month later it shifted to the southern Mazatlán Bay while in California, USA, incidents of the poisoning of sea mammals were being recorded; this also happened on the Mexican Pacific coasts from January to March. Water samples collected at surface (<0.5 m deep and subsurface (10 m deep monthly, from November 1998 to January 1999 and every week from February 1999 to May 2000, were analyzed by the Utermöhl technique at 400 enlargements. Phytoplankton quantification showed winter and summer pulses; the 1998-1999 period was higher than the 1999-2000 period. Five species of Pseudo-nitzschia were identified by electron microscopy (TEM and SEM; a new study has revealed other species. High values of Pseudo-nitzschia were observed: 730 P-n/ml (Dec. 1999, 610 P-n/ml (Dec. 1998, 335 P-n/ml (Jul. 1999, 198 P-n/ml (Feb. 1999, 170 P-n/ml (Nov. 1998, 123 P-n/ml (Mar. 1999, 108 P-n/ml (Aug. 1999. The blooms of other species of diatoms (Thalassiosira spp., Asterionellopsis glacialis, Chaetoceros spp., Skeletonema costatum, dinoflagellates (Prorocentrum spp., Scripsiella trochoidea and ciliates (Myrionecta rubra were also observed

  14. Pseudo-nitzschia seriata f. obtusa (Bacillariophyceae) raised in rank based onmorphological, phylogenetic and distributional data

    DEFF Research Database (Denmark)

    Hasle, Grethe Rytter; Lundholm, N.

    2005-01-01

    hymenate poroids. Within that clade, P. obtusa is most closely related to P. seriata and P. australis, which make up the sister group to P. obtusa. Pseudo-nitzschia obtusa is recorded from the Arctic regions of the Atlantic and the Pacific Oceans, whereas P. seriata is recorded from the Arctic...... and Temperate regions but only from the Atlantic Ocean. The relationship between P. obtusa and other morphologically and phylogenetically similar species of the genus is discussed. In growth studies under replete nutrient conditions, P. obtusa had a growth rate of 0.55-0.66 day-1 and an upper pH limit...... for growth of 9.1. No P. obtusa clones have yet been shown to produce the toxin, domoic acid....

  15. Intraspecific diversity and distribution of the cosmopolitan species Pseudo-nitzschia pungens (Bacillariophyceae): morphology, genetics, and ecophysiology of the three clades.

    Science.gov (United States)

    Kim, Jin Ho; Park, Bum Soo; Kim, Joo-Hwan; Wang, Pengbin; Han, Myung-Soo

    2015-02-01

    Three clades of Pseudo-nitzschia pungens, determined by the internal transcribed space (ITS) region, are distributed throughout the world. We studied 15 P. pungens clones from various geographical locations and confirmed the existence of the three clades within P. pungens, based on ITS sequencing and described the three subgroups (IIIaa, IIIab, and IIIb) of clade III. Clade III (clade IIIaa) populations were reported for the first time in Korean coastal waters and the East China Sea. In morphometric analysis, we found the ultrastructural differences in the number of fibulae, striae, and poroids that separate the three clades. We carried out physiological tests on nine clones belonging to the three clades growing under various culture conditions. In temperature tests, only clade III clones could not grow at lower temperatures (10°C and 15°C), although clade I and II clones grew well. The estimated optimal growth range of clade I clones was wider than that of clades II and III. Clade II clones were considered to be adapted to lower temperatures and clade III to higher temperatures. In salinity tests, clade II and III clones did not grow well at a salinity of 40. Clade I clones were regarded as euryhaline and clade II and III clones were stenohaline. This supports the hypothesis that P. pungens clades have different ecophysiological characteristics based on their habitats. Our data show that physiological and morphological features are correlated with genetic intraspecific differentiation in P. pungens. © 2014 Phycological Society of America.

  16. POPULATION DYNAMICS OF PSEUDO-NITZSCHIA SPECIES ...

    African Journals Online (AJOL)

    nb

    ABSTRACT. The genus Pseudo-nitzschia is a chain-forming diatom comprising about 30 species some of which are known to produce domoic acid (DA) that causes amnesic shellfish poisoning (ASP). The current study aimed at assessing the population dynamics of Pseudo-nitzschia in the near shore waters of Dar es ...

  17. Population dynamics of Pseudo-nitzschia species ...

    African Journals Online (AJOL)

    The genus Pseudo-nitzschia is a chain-forming diatom comprising about 30 species some of which are known to produce domoic acid (DA) that causes amnesic shellfish poisoning (ASP). The current study aimed at assessing the population dynamics of Pseudo-nitzschia in the near shore waters of Dar es Salaam. Samples ...

  18. POPULATION DYNAMICS OF PSEUDO-NITZSCHIA SPECIES ...

    African Journals Online (AJOL)

    nb

    coastal waters of the Western Indian Ocean has been reported before (Bryceson ... Ocean. There is however no study, which has analyzed the seasonal distribution of. Pseudo-nitzschia species along the. Tanzanian coastal waters as well as factors regulating such ... cleaned plastic vials and immediately kept cool on ice for ...

  19. Pseudo-nitzschia species on the Catalan coast: characterization and contribution to the current knowledge of the distribution of this genus in the Mediterranean Sea

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    Sonia Quijano-Scheggia

    2010-04-01

    Full Text Available Proliferations of the genus Pseudo-nitzschia recur along the Catalan coast (NW Mediterranean throughout the year. The establishment of 58 clonal cultures facilitated morphological studies with scanning electron microscopy (SEM and ITS 5.8S rDNA sequence characterization. Moreover, strains of each species were examined with respect to sexual compatibility and toxicity. The results of the morphological and phylogenetic studies confirmed nine species of the genus Pseudo-nitzschia: P. brasiliana, P. calliantha, P. delicatissima clade A/del 2, P. arenysensis, P. fraudulenta, P. galaxiae, P. linea, P. multistriata and P. pungens clade I. Moreover, two Pseudo-nitzschia species, P. caciantha and P. cf mannii, could only be identified following SEM analysis of their morphology. None of the cultured strains of Pseudo-nitzschia analyzed produced domoic acid in amounts above the limit of detection. The current distributions of the Pseudo-nitzschia species in the Mediterranean Sea were plotted on maps, which led to the following observations: i diversity within this genus is much greater than previously considered, ii some species have a broad distribution (e.g. P. calliantha, iii whereas the distribution of others is narrowly restricted (e.g. P. pungens clade I. Moreover, this study reports the first detection of P. linea in the Mediterranean Sea and is the first description of P. galaxiae and P. cf mannii along the Catalan coast. Morphological studies coupled with molecular biological characterization, mating tests and biogeographic distribution analyses provide a critical theoretical basis for testing and/or implementing the current phylogenetic framework in the genus Pseudo-nitzschia.

  20. Pseudo-nitzschia blooms and physical oceanography off ...

    African Journals Online (AJOL)

    During three surveys conducted in early summer 1996, 1997 and 1998, high concentrations of. Pseudo-nitzschia spp. (values of up to 106 cells.l-1, but generally <105 cells.l-1) were present. P. pungens was dominant in 1996, whereas P. pseudodelicatissima was most abundant in 1997 and 1998. A. catenella was rare and ...

  1. West Coast DA Event data - West Coast Toxic Pseudo-nitzschia bloom

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Beginning in the spring of 2015 the US West Coast began to experience the most wide-spread toxic Pseudo-nitzschia bloom to date, after approximately eight years...

  2. The application of species specific DNA-targeted probes and fluorescently tagged lectin to differentiate several species of Pseudo-nitzschia (Bacillophyceae in Chinhae Bay, Korea

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    Eun Seob Cho

    2001-09-01

    Full Text Available We applied molecular methods using a DNA probe and fluorescently tagged lectins to discriminate toxic Pseudo-nitzschia multiseries from the Chinhae Bay for a Korean harmfulalgae monitoring program. From the binding activity of lectins, P. multistriata, P. subfraudulenta, P. pungens, P. multiseries and P. cuspidata bound ConA, whereas P. subpacifica and P. delicatissima did not. Ribosomal RNA-targeted oligonucleotide probes (muD1, puD1 and deD1 specifically reacted to P. multiseries, P. pungens and P. delicatissima, respectively, whereas auD1, frD1 and amD1 probes did not bind to P. multiseries, P. pungens, P. cuspidata, P. multistriata, P. subpacifica, P. subfraudulenta and P. delicatissima. In particular, fluorescent FITC-conjugated WGA specifically bound to P. multiseries but not to P. pungens, indicating that this is a desirable method for their rapid and easy discrimination. In addition, we tested a species-specific oligonucleotide DNA probe (muD1 using the whole cell hybridization filter tube system, and the WGA lectin probe to discriminate P. multiseries in the field. The oligonucleotide probe and fluorescent WGA bound specifically to P. multiseries and these labelled cells were correlated to label cell abundance. These results imply that DNA and lectin probes are apporopriate tools for counting P. multiseries and distinguishing morphologically similar Pseudo-nitzschia species in natural samples, therefore, these methods are especially pertinent since rapid separation and quantitative estimation of cell abundance of P. multiseries are now important for a routine harmful algae monitoring program in Korean waters.

  3. Variation in the abundance of Pseudo-nitzschia and domoic acid with surf zone type.

    Science.gov (United States)

    Shanks, Alan L; Morgan, Steven G; MacMahan, Jamie; Reniers, Ad J H M; Kudela, Raphael; Jarvis, Marley; Brown, Jenna; Fujimura, Atsushi; Ziccarelli, Lisa; Griesemer, Chris

    2016-05-01

    Most harmful algal blooms (HAB) originate away from the shore and, for them to endanger human health, they must be first transported to shore after which they must enter the surf zone where they can be feed upon by filter feeders. The last step in this sequence, entrance into the surf zone, depends on surf zone hydrodynamics. During two 30-day periods, we sampled Pseudo-nitzschia and particulate domoic acid (pDA) in and offshore of a more dissipative surf zone at Sand City, California (2010) and sampled Pseudo-nitzschia in and out of reflective surf zones at a beach and rocky shores at Carmel River State Beach, California (2011). At Sand City, we measured domoic acid in sand crabs, Emerita analoga. In the more dissipative surf zone, concentrations of Pseudo-nitzschia and pDA were an order of magnitude higher in samples from a rip current than in samples collected just seaward of the surf zone and were 1000 times more abundant than in samples from the shoals separating rip currents. Domoic acid was present in all the Emerita samples and varied directly with the concentration of pDA and Pseudo-nitzschia in the rip current. In the more reflective surf zones, Pseudo-nitzschia concentrations were 1-2 orders of magnitude lower than in samples from 125 and 20m from shore. Surf zone hydrodynamics affects the ingress of Pseudo-nitzschia into surf zones and the exposure of intertidal organisms to HABs on the inner shelf. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Diversity of Pseudo-nitzschia H. Peragallo from the western North Pacific

    DEFF Research Database (Denmark)

    Stonik, Inna V.; Orlova, Tatiana Yu; Lundholm, Nina

    2011-01-01

    Asurvey focusing on species belonging to the diatom genus Pseudo-nitzschia was conducted in the western North Pacific (the northwestern Sea of Japan and the Sea of Okhotsk). Light and electron microscopic examination of 314 phytoplankton field samples collected from 1995 to 2006 revealed the pres......Asurvey focusing on species belonging to the diatom genus Pseudo-nitzschia was conducted in the western North Pacific (the northwestern Sea of Japan and the Sea of Okhotsk). Light and electron microscopic examination of 314 phytoplankton field samples collected from 1995 to 2006 revealed...

  5. Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impact on ecosystem health

    DEFF Research Database (Denmark)

    Trainer, Vera L.; Bates, Steve S.; Lundholm, Nina

    2012-01-01

    is complex and likely influenced by a suite of environmental factors that may be unique to a particular region. Advances in our knowledge of Pseudo-nitzschia sexual reproduction, also in field populations, illustrate its importance in bloom dynamics and toxicity. The combination of careful taxonomy...

  6. Specificity of lipoxygenase pathways supports species delineation in the marine diatom genus Pseudo-nitzschia.

    Directory of Open Access Journals (Sweden)

    Nadia Lamari

    Full Text Available Oxylipins are low-molecular weight secondary metabolites derived from the incorporation of oxygen into the carbon chains of polyunsaturated fatty acids (PUFAs. Oxylipins are produced in many prokaryotic and eukaryotic lineages where they are involved in a broad spectrum of actions spanning from stress and defense responses, regulation of growth and development, signaling, and innate immunity. We explored the diversity in oxylipin patterns in the marine planktonic diatom Pseudo-nitzschia. This genus includes several species only distinguishable with the aid of molecular markers. Oxylipin profiles of cultured strains were obtained by reverse phase column on a liquid chromatograph equipped with UV photodiode detector and q-ToF mass spectrometer. Lipoxygenase compounds were mapped on phylogenies of the genus Pseudo-nitzschia inferred from the nuclear encoded hyper-variable region of the LSU rDNA and the plastid encoded rbcL. Results showed that the genus Pseudo-nitzschia exhibits a rich and varied lipoxygenase metabolism of eicosapentaenoic acid (EPA, with a high level of specificity for oxylipin markers that generally corroborated the genotypic delineation, even among genetically closely related cryptic species. These results suggest that oxylipin profiles constitute additional identification tools for Pseudo-nitzschia species providing a functional support to species delineation obtained with molecular markers and morphological traits. The exploration of the diversity, patterns and plasticity of oxylipin production across diatom species and genera will also provide insights on the ecological functions of these secondary metabolites and on the selective pressures driving their diversification.

  7. Pseudo-nitzschia challenged with co-occurring viral communities display diverse infection phenotypes

    Directory of Open Access Journals (Sweden)

    Michael Curtis Grier Carlson

    2016-04-01

    Full Text Available Viruses are catalysts of biogeochemical cycling, architects of microbial community structure, and terminators of phytoplankton blooms. Viral lysis of diatoms, a key group of eukaryotic phytoplankton, has the potential to impact carbon export and marine food webs. However, the impact of viruses on diatom abundance and community composition is unknown. Diatom-virus dynamics were explored by sampling every month at 2 coastal and estuarine locations in Washington state, USA resulting in 41 new isolates of the pennate diatom Pseudo-nitzschia and 20 environmental virus samples. We conducted a total of 820 pair-wise crosses of the Pseudo-nitzschia isolates and viral communities. Viral communities infected Pseudo-nitzschia isolates in 8% of the crosses overall and 16% of crosses when the host and viral communities were isolated from the same sample. Isolates ranged in their permissivity to infection with some isolates not infected by any viral samples and others infected by up to 10 viral communities. Isolates that were infected by the most viral communities also had the highest maximum observed viral titers (as high as 16000 infectious units ml-1. Titers of the viral communities were host dependent, as titers for one viral sample on 8 different hosts spanned 4 orders of magnitude. Sequencing of the Pseudo-nitzschia Internal Transcribed Spacer 1 (ITS1 of the revealed multiple subgroups of hosts with 100% ITS1 identity that were infected by different viral communities. Indeed, we repeatedly isolated groups of isolates with identical ITS1 sequences from the same water sample that displayed different viral infection phenotypes. The interactions between Pseudo-nitzschia and the viral communities highlight the diversity of diatoms and emphasize the complexity and variability of diatom-virus dynamics in the ocean.

  8. An ecological study of a massive bloom of toxigenic Pseudo-nitzschia cuspidata off the Washington State coast

    DEFF Research Database (Denmark)

    Trainer, Vera; Wells, Mark L; Cochlan, William P

    2009-01-01

    concentrations of 43 nmol L-11, 4 nmol L-1, and 63 pg cell-1, respectively. This bloom co-dominated the phytoplankton assemblage with the euglenoid Eutreptiella sp. in the Juan de Fuca eddy region, a known initiation site for toxigenic Pseudo-nitzschia blooms. Two isolates of P. cuspidata collected during......, when considering only those stations where Pseudo-nitzschia was present, pDA was positively correlated with chlorophyll a and negatively correlated with temperature (p

  9. Domoic Acid Improves the Competitive Ability of Pseudo-nitzschia delicatissima against the Diatom Skeletonema marinoi

    Directory of Open Access Journals (Sweden)

    Emily K. Prince

    2013-07-01

    Full Text Available Because domoic acid, a neurotoxic secondary metabolite produced by marine diatoms in the genus Pseudo-nitzschia, is hypothesized to be part of a high affinity iron uptake system, we investigated whether domoic acid could improve the competitive ability of Pseudo-nitzschia delicatissima, and whether the availability of iron changed the outcome of competition experiments. We found that domoic acid had a slight negative effect on growth of the diatom Skeletonema marinoi when it was grown in monocultures. However, when S. marinoi was cultured with P. delicatissima the presence of domoic acid resulted in a reduction of S. marinoi cells by up to 38% and an increase in P. delicatissima cell numbers by up to 17% under iron replete conditions. Similar effects were not observed in low iron treatments. Domoic acid was not taken up by P. delicatissima cells. Overall, our results indicate that domoic acid can improve the competitive ability of Pseudo-nitzschia spp. and that iron is likely to be involved. This study provides an unusual example of indirect inhibition of competitor growth mediated by a secondary metabolite.

  10. Using ATTO dyes to probe bacterial interactions with the marine diatom Pseudo-nitzschia.

    Science.gov (United States)

    Mehic, S.; Sison-Mangus, M.

    2016-02-01

    Pseudo-nitzschia blooms are known to be highly toxic and detrimental to wildlife. The neurotoxin produced by the algae can ripple through the entire food web creating a direct impact on oceanic life and human-related industries. With coastal blooms increasing in both size and duration in recent years, it is crucial that we uncover more microbial interactions that may affect the toxicity of these blooms. Current harmful algal bloom studies have shown that different bacterial consortia can have a great impact Pseudo-nitzschia physiology. More specifically, research suggests that bacteria affect both growth rates and domoic acid concentrations of laboratory grown cultures. However, these studies do not explore the attachment patterns of these bacteria with the diatom. Bacterial attachment may dictate the different types of interactions between bacteria and the diatoms, a trait that is largely unexplored in the symbiotic interactions between the two organisms. In this study, we seek to identify direct and indirect interactions between four bacteria taxa from different phyla and three different species of Pseudo-nitzschia. Our preliminary scanning electron microscopy and DAPI staining experiments hint at distinct differences in attachment among bacterial taxa. To explore this work further, we aim to employ ATTO dyes and epifluorescent microscopy on both binary and multiple cultures to visualize patterns in attachment. By utilizing ATTO dyes with distinct wavelength emissions, we can perform a series experiment that highlights the interaction between bacteria and diatoms, without inserting a fluorescent reporter gene in the bacteria. Multiple cultures will be used to identify possible cooperative or negative interactive traits between bacteria that can affect diatom host physiology. Implications on both phytoplankton physiology and nutrient cycling will be subsequently discussed.

  11. Growth, Toxin Production and Allelopathic Effects of Pseudo-nitzschia multiseries under Iron-Enriched Conditions.

    Science.gov (United States)

    Sobrinho, Bruna Fernanda; de Camargo, Luana Mocelin; Sandrini-Neto, Leonardo; Kleemann, Cristian Rafael; Machado, Eunice da Costa; Mafra, Luiz Laureno

    2017-10-24

    In order to assess the effects of Fe-enrichment on the growth and domoic acid (DA) production of the toxigenic diatom Pseudo-nitzschia multiseries, static cultures that received the addition of different iron (Fe) concentrations were maintained for 30 days. Intra- and extracellular DA concentrations were evaluated over time, and growth and chain-formation were compared to those of non-toxic diatoms, Bacillaria sp. Growth rates of P. multiseries (μ = 0.45-0.73 d-1) were similar among cultures containing different Fe concentrations. Likewise, the similar incidence and length of P. multiseries stepped cell chains (usually 2-4; up to 8-cell long) among the treatments reinforces that the cultures were not growth-inhibited under any condition tested, suggesting an efficient Fe acquisition mechanism. Moreover, DA concentrations were significantly higher under the highest Fe concentration, indicating that Fe is required for toxin synthesis. Bacillaria sp. reached comparable growth rates under the same Fe concentrations, except when the dissolved cell contents from a P. multiseries culture was added. The 50-70% reduction in cell density and 70-90% decrease in total chlorophyll-a content of Bacillaria sp. at early stationary growth phase indicates, for the first time, an allelopathic effect of undetermined compounds released by Pseudo-nitzschia to another diatom species.

  12. Growth, Toxin Production and Allelopathic Effects of Pseudo-nitzschia multiseries under Iron-Enriched Conditions

    Directory of Open Access Journals (Sweden)

    Bruna Fernanda Sobrinho

    2017-10-01

    Full Text Available In order to assess the effects of Fe-enrichment on the growth and domoic acid (DA production of the toxigenic diatom Pseudo-nitzschia multiseries, static cultures that received the addition of different iron (Fe concentrations were maintained for 30 days. Intra- and extracellular DA concentrations were evaluated over time, and growth and chain-formation were compared to those of non-toxic diatoms, Bacillaria sp. Growth rates of P. multiseries (μ = 0.45–0.73 d−1 were similar among cultures containing different Fe concentrations. Likewise, the similar incidence and length of P. multiseries stepped cell chains (usually 2–4; up to 8-cell long among the treatments reinforces that the cultures were not growth-inhibited under any condition tested, suggesting an efficient Fe acquisition mechanism. Moreover, DA concentrations were significantly higher under the highest Fe concentration, indicating that Fe is required for toxin synthesis. Bacillaria sp. reached comparable growth rates under the same Fe concentrations, except when the dissolved cell contents from a P. multiseries culture was added. The 50–70% reduction in cell density and 70–90% decrease in total chlorophyll-a content of Bacillaria sp. at early stationary growth phase indicates, for the first time, an allelopathic effect of undetermined compounds released by Pseudo-nitzschia to another diatom species.

  13. Diversity and toxicity of the diatom Pseudo-nitzschia Peragallo in the Gulf of Maine, Northwestern Atlantic Ocean.

    Science.gov (United States)

    Fernandes, Luciano F; Hubbard, Katherine A; Richlen, Mindy L; Smith, Juliette; Bates, Stephen S; Ehrman, James; Léger, Claude; Mafra, Luiz L; Kulis, David; Quilliam, Michael; Libera, Katie; McCauley, Linda; Anderson, Donald M

    2014-05-01

    Multiple species in the toxic marine diatom genus Pseudo-nitzschia have been identified in the Northwestern Atlantic region encompassing the Gulf of Maine (GOM), including the Bay of Fundy (BOF). To gain further knowledge of the taxonomic composition and toxicity of species in this region, Pseudo-nitzschia isolates (n=146) were isolated from samples collected during research cruises that provided broad spatial coverage across the GOM and the southern New England shelf, herein referred to as the GOM region, during 2007-2008. Isolates, and cells in field material collected at 38 stations, were identified using electron microscopy (EM). Eight species (P. americana, P. fraudulenta, P. subpacifica, P. heimii, P. pungens, P. seriata, P. delicatissima and P. turgidula), and a novel form, Pseudo-nitzschia sp. GOM, were identified. Species identity was confirmed by sequencing the large subunit of the ribosomal rDNA (28S) and the internal transcribed spacer 2 (ITS2) for six species (36 isolates). Phylogenetic analyses (including neighbor joining, maximum parsimony, and maximum likelihood estimates and ITS2 secondary structure analysis) and morphometric data supported the placement of P. sp. GOM in a novel clade that includes morphologically and genetically similar isolates from Australia and Spain and is genetically most similar to P. pseudodelicatissima and P. cuspidata. Seven species (46 isolates) were grown in nutrient-replete batch culture and aliquots consisting of cells and growth medium were screened by Biosense ASP ELISA to measure total domoic acid (DA) produced (intracellular + extracellular); P. americana and P. heimii were excluded from all toxin analyses as they did not persist in culture long enough for testing. All 46 isolates screened produced DA in culture and total DA varied among species (e.g., 0.04 to 320 ng ml(-1) for P. pungens and P. sp. GOM isolates, respectively) and among isolates of the same species (e.g., 0.24 - 320 ng ml(-1) for P. sp. GOM). The

  14. The effect of Pseudo-nitzschia seriata on grazing and fecundity of Calanus finmarchicus and Calanus glacialis

    DEFF Research Database (Denmark)

    Miesner, Anna Katharina; Lundholm, Nina; Krock, Bernd

    2016-01-01

    This study investigates whether feeding on the domoic acid (DA)-producing diatom Pseudo-nitzschia seriata affects the faecal pellet (FP) production (proxy for grazing) and fecundity of Calanus finmarchicus and Calanus glacialis. Female copepods were fed a saturating concentration of food (400 mg C...... in both species. Compared with C. finmarchicus, C. glacialis accumulated substantially more DA in its body tissue. For both species, egg production and hatching success were unaffected by grazing on the toxic diatom. This suggests that feeding on DA-containing P. seriata does not affect copepod fecundity...

  15. Support Vector Machine-based method for predicting Pseudo-nitzschia spp. blooms in coastal waters (Galician rias, NW Spain)

    Science.gov (United States)

    González Vilas, Luis; Spyrakos, Evangelos; Torres Palenzuela, Jesus M.; Pazos, Yolanda

    2014-05-01

    Phytoplanktonic blooms in the coastal embayments (rias) at the NW part of Spain were mentioned for the first time in 1918 and since then they have been associated numerous times with negatives impacts to a very important economic activity in the area, mussel production. In this study, eight years of Pseudo-nitzschia spp. abundance and associated meteorological and oceanographic data were used to develop and validate support vector machine (SVM) models for the prediction of these diatoms. SVM were used to identify presence/below low detection limit, bloom/no bloom conditions of Pseudo-nitzschia spp. and finally to predict blooms due to these diatoms in the coastal systems of the Galician rias. The best SVM models were selected on the basis of C and γ parameters and their performance was evaluated in terms of accuracy and kappa statistics (κ). Regarding the presence/below low detection limit, bloom/no bloom models the best results in the validation dataset were achieved using all the variables: ria code, day of the year, temperature, salinity, upwelling indices and bloom occurrence in previous weeks. The best performing models were also tested in an independent dataset from the study area, where they showed high overall accuracy (78.53-82.18%), κ values (0.77-0.81) and true positive rates (62.60-78.18). In these models the bloom occurrence in previous weeks was identified as a key parameter to the prediction performance. In this paper, toxic Pseudo-nitzschia blooms could not be predicted due to limited information on toxin concentration and species composition. Nevertheless, this study demonstrates that the approach followed here is capable for high predictive performance which could be of great aid in the monitoring of algal blooms and offer valuable information to the local shellfish industry. The reliable prediction of categorical Pseudo-nitzschia abundances using variables that are operationally determined or short-term predicted could provide early warning of

  16. Coastal upwelling linked to toxic Pseudo-nitzschia australis blooms in Los Angeles coastal waters, 2005-2007

    KAUST Repository

    Schnetzer, Astrid

    2013-06-10

    Harmful algal blooms dominated by the diatom Pseudo-nitzschia spp. have become a perennial but variable event within surface waters near the greater Los Angeles area. Toxic blooms during spring seasons from 2005 to 2007 varied strongly in their overall toxicity and duration. Differences in bloom dynamics were linked to differences in storm-induced river discharge following episodic rain events and coastal upwelling, both major coastal processes that led to the injection of nutrients into coastal surface waters. Heavy river runoff during early 2005, a record-rainfall year, favored a phytoplankton community mainly comprised of algal taxa other than Pseudo-nitzschia. The spring bloom during 2005 was associated with low domoic acid surface concentrations and minor contributions of (mainly) P. delicatissima to the diatom assemblage. In contrast, highly toxic P. australis-dominated blooms during spring seasons of 2006 and 2007 were linked to strong upwelling events. River discharge quotas in 2006 and 2007, in contrast to 2005, fell well below annual averages for the region. Surface toxin levels were linked to colder, more saline (i.e. upwelled) water over the 3-year study, but no such consistent relationship between domoic acid levels and other physiochemical parameters, such as macronutrient concentrations or nutrient ratios, was observed. © The Author 2013. Published by Oxford University Press. All rights reserved.

  17. SEASONAL AND SPATIAL PATTERNS OF TOXIGENIC SPECIES OF Dinophysis AND Pseudo-nitzschia IN A SUBTROPICAL BRAZILIAN ESTUARY

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Junqueira de Azevedo Tibiriçá

    2015-03-01

    Full Text Available This study investigated the spatial and temporal distributions of toxigenic phytoplankton species between October 2010 and April 2012 in Guaratuba Bay, Paraná state, Brazil, where aquaculture has been intensified in recent years. The highest abundances of Pseudo-nitzschia calliantha and P. pungens (up to 7.3 x 104 cells L-1, diatoms which cause amnesic shellfish poisoning (ASP, were correlated with higher values of temperature (from December to April, salinity (>20 and silicate concentrations (ranging from 6.0 to 90.0 µm. The occurrence of these harmful diatoms in the bay also appeared to depend upon the development of seeding mechanisms in the adjacent coastal water and its subsequent advection by tidal currents to the interior of the estuary. During the study period, Pseudo-nitzschia cell abundance remained low to moderate probably as a result of growth limitation by phosphate shortage, especially in the outer area of the estuary. In addition, harmful species of Dinophysis, dinoflagellates responsible for diarrhetic shellfish poisoning (DSP events, were recorded in every sampling campaign. The highest abundances of D. acuminata, D. caudata and D. tripos were associated with the upper halocline layer in regions of the bay where water column stratification was more frequent. On some occasions, cell abundances of D. acuminata (up to 3.2 x 103 cells L-1 exceeded levels considered harmful in areas used to cultivate bivalve mollusks for human consumption. These novel results strongly indicate the necessity of implementing a monitoring program for harmful microalgae in Guaratuba Bay.

  18. Individual and interactive effects of warming and CO2 on Pseudo-nitzschia subcurvata and Phaeocystis antarctica, two dominant phytoplankton from the Ross Sea, Antarctica

    OpenAIRE

    Zhu, Zhi; Qu, Pingping; Gale, Jasmine; Fu, Feixue; Hutchins, David A.

    2017-01-01

    We investigated the effects of temperature and CO2 variation on the growth and elemental composition of cultures of the diatom Pseudo-nitzschia subcurvata and the prymnesiophyte Phaeocystis antarctica, two ecologically dominant phytoplankton species isolated from the Ross Sea, Antarctica. To obtain thermal functional response curves, cultures were grown across a range of temperatures from 0 °C to 14 °C. In addition, a competition experiment examined the relative abundanc...

  19. Species occurrence of the potentially toxigenic diatom genus Pseudo-nitzschia and the associated neurotoxin domoic acid in the Argentine Sea.

    Science.gov (United States)

    Almandoz, Gastón O; Fabro, Elena; Ferrario, Martha; Tillmann, Urban; Cembella, Allan; Krock, Bernd

    2017-03-01

    The marine diatom genus Pseudo-nitzschia, the major known producer of the neurotoxin domoic acid (DA) responsible for the amnesic shellfish poisoning (ASP) syndrome in humans and marine mammals, is globally distributed. The genus presents high species richness in the Argentine Sea and DA has been frequently detected in the last few years in plankton and shellfish samples, but the species identity of the producers remains unclear. In the present work, the distribution and abundance of Pseudo-nitzschia species and DA were determined from samples collected on two oceanographic cruises carried out through the Argentine Sea (∼39-47°S) during summer and spring 2013. Phytoplankton composition was analysed by light and electron microscopy while DA was determined by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The genus Pseudo-nitzschia was recorded in 71 and 86% of samples collected in summer and spring, respectively, whereas DA was detected in only 42 and 21% of samples, respectively. Microscopic analyses revealed at least five potentially toxic species (P. australis, P. brasiliana, P. fraudulenta, P. pungens, P. turgidula), plus putatively non-toxigenic P. dolorosa, P. lineola, P. turgiduloides and unidentified specimens of the P. pseudodelicatissima complex. The species P. australis showed the highest correlation with DA occurrence (r=0.55; p<0.05), suggesting its importance as a major DA producer in the Argentine Sea. In the northern area and during summer, DA was associated with the presence of P. brasiliana, a species recorded for the first time in the Argentine Sea. By contrast, high concentrations of P. fraudulenta, P. pungens and P. turgidula did not correspond with DA occurrence. This study represents the first successful attempt to link toxigenicity with Pseudo-nitzschia diversity and cell abundance in field plankton populations in the south-western Atlantic. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Understanding the blob bloom: Warming increases toxicity and abundance of the harmful bloom diatom Pseudo-nitzschia in California coastal waters.

    Science.gov (United States)

    Zhu, Zhi; Qu, Pingping; Fu, Feixue; Tennenbaum, Nancy; Tatters, Avery O; Hutchins, David A

    2017-07-01

    The toxic diatom genus Pseudo-nitzschia produces environmentally damaging harmful algal blooms (HABs) along the U.S. west coast and elsewhere, and a recent ocean warming event coincided with toxic blooms of record extent. This study examined the effects of temperature on growth, domoic acid toxin production, and competitive dominance of two Pseudo-nitzschia species from Southern California. Growth rates of cultured P. australis were maximal at 23°C (∼0.8d-1), similar to the maximum temperature recorded during the 2014-2015 warming anomaly, and decreased to ∼0.1 d-1 by 30°C. In contrast, cellular domoic acid concentrations only became detectable at 23°C, and increased to maximum levels at 30°C. In two incubation experiments using natural Southern California phytoplankton communities, warming also increased the relative abundance of another potentially toxic local species, P. delicatissima. These results suggest that both the toxicity and the competitive success of particular Pseudo-nitzschia spp. can be positively correlated with temperature, and therefore there is a need to determine whether harmful blooms of this diatom genus may be increasingly prevalent in a warmer future coastal ocean. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Gene expression studies for the analysis of domoic acid production in the marine diatom Pseudo-nitzschia multiseries.

    Science.gov (United States)

    Boissonneault, Katie Rose; Henningsen, Brooks M; Bates, Stephen S; Robertson, Deborah L; Milton, Sean; Pelletier, Jerry; Hogan, Deborah A; Housman, David E

    2013-11-01

    Pseudo-nitzschia multiseries Hasle (Hasle) (Ps-n) is distinctive among the ecologically important marine diatoms because it produces the neurotoxin domoic acid. Although the biology of Ps-n has been investigated intensely, the characterization of the genes and biochemical pathways leading to domoic acid biosynthesis has been limited. To identify transcripts whose levels correlate with domoic acid production, we analyzed Ps-n under conditions of high and low domoic acid production by cDNA microarray technology and reverse-transcription quantitative PCR (RT-qPCR) methods. Our goals included identifying and validating robust reference genes for Ps-n RNA expression analysis under these conditions. Through microarray analysis of exponential- and stationary-phase cultures with low and high domoic acid production, respectively, we identified candidate reference genes whose transcripts did not vary across conditions. We tested eleven potential reference genes for stability using RT-qPCR and GeNorm analyses. Our results indicated that transcripts encoding JmjC, dynein, and histone H3 proteins were the most suitable for normalization of expression data under conditions of silicon-limitation, in late-exponential through stationary phase. The microarray studies identified a number of genes that were up- and down-regulated under toxin-producing conditions. RT-qPCR analysis, using the validated controls, confirmed the up-regulation of transcripts predicted to encode a cycloisomerase, an SLC6 transporter, phosphoenolpyruvate carboxykinase, glutamate dehydrogenase, a small heat shock protein, and an aldo-keto reductase, as well as the down-regulation of a transcript encoding a fucoxanthin-chlorophyll a-c binding protein, under these conditions. Our results provide a strong basis for further studies of RNA expression levels in Ps-n, which will contribute to our understanding of genes involved in the production and release of domoic acid, an important neurotoxin that affects human

  2. Transcriptional response after exposure to domoic acid-producing Pseudo-nitzschia in the digestive gland of the mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Pazos, Antonio J; Ventoso, Pablo; Martínez-Escauriaza, Roi; Pérez-Parallé, M Luz; Blanco, Juan; Triviño, Juan C; Sánchez, José L

    2017-12-15

    Bivalve molluscs are filter feeding species that can accumulate biotoxins in their body tissues during harmful algal blooms. Amnesic Shellfish Poisoning (ASP) is caused by species of the diatom genus Pseudo-nitzschia, which produces the toxin domoic acid. The Mytilus galloprovincialis digestive gland transcriptome was de novo assembled based on the sequencing of 12 cDNA libraries, six obtained from control mussels and six from mussels naturally exposed to domoic acid-producing diatom Pseudo-nitzschia australis. After de novo assembly 94,727 transcripts were obtained, with an average length of 1015 bp and a N50 length of 761 bp. The assembled transcripts were clustered (homology > 90%) into 69,294 unigenes. Differential gene expression analysis was performed (DESeq2 algorithm) in the digestive gland following exposure to the toxic algae. A total of 1158 differentially expressed unigenes (absolute fold change > 1.5 and p-value families were found to be significantly (FDR adjusted p-value families (sulfotransferases, aldo/keto reductases, carboxylesterases, C1q domain and fibrinogen C-terminal globular domain) could be putatively involved in detoxification processes, in the response against of the oxidative stress and in immunological processes. Protein network analysis with STRING algorithm found alteration of the Notch signaling pathway under the action of domoic acid-producing Pseudo-nitzschia. In conclusion, this study provides a high quality reference transcriptome of M. galloprovincialis digestive gland and identifies potential genes involved in the response to domoic acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Blooms of Pseudo-nitzschia and Domoic Acid in the San Pedro Channel and Los Angeles Harbor Areas of the Southern California Bight, 2003–2004

    OpenAIRE

    Schnetzer, Astrid; Miller, Peter E.; Schaffner, Rebecca; Stauffer, Beth; Jones, Burton H.; Weisberg, Stephen B.; DiGiacomo, Paul M.; Berelson, William M.; David A. Caron

    2007-01-01

    Abundances of Pseudo-nitzschia spp. and concentrations of particulate domoic acid (DA) were determined in the Southern California Bight (SCB) along the coasts of Los Angeles and Orange Counties during spring and summer of 2003 and 2004. At least 1500 km2 were affected by a toxic event in May/June of 2003 when some of the highest particulate DA concentrations reported for US coastal waters were measured inside the Los Angeles harbor (12.7 μg DA L−1). Particulate DA levels were an order of magn...

  4. Morphology, physiology, molecular phylogeny and sexual compatibility of the cryptic Pseudo-nitzschia delicatissima complex (Bacillariophyta), including the description of P. arenysensis sp. nov

    DEFF Research Database (Denmark)

    Quijano-Scheggia, Sonia; Garces, Esther; Lundholm, Nina

    2009-01-01

    Several strains of Pseudo-nitzschia delicatissima were isolated from the northwestern Mediterranean Sea and compared using light and electron microscopy, phylogenetic analyses of internal transcribed spacer rDNA, together with studies of their mating system, estimations of growth rates and reduct...

  5. Individual and interactive effects of warming and CO2 on Pseudo-nitzschia subcurvata and Phaeocystis antarctica, two dominant phytoplankton from the Ross Sea, Antarctica

    Science.gov (United States)

    Zhu, Zhi; Qu, Pingping; Gale, Jasmine; Fu, Feixue; Hutchins, David A.

    2017-11-01

    We investigated the effects of temperature and CO2 variation on the growth and elemental composition of cultures of the diatom Pseudo-nitzschia subcurvata and the prymnesiophyte Phaeocystis antarctica, two ecologically dominant phytoplankton species isolated from the Ross Sea, Antarctica. To obtain thermal functional response curves, cultures were grown across a range of temperatures from 0 to 14 °C. In addition, a co-culturing experiment examined the relative abundance of both species at 0 and 6 °C. CO2 functional response curves were conducted from 100 to 1730 ppm at 2 and 8 °C to test for interactive effects between the two variables. The growth of both phytoplankton was significantly affected by temperature increase, but with different trends. Growth rates of P. subcurvata increased with temperature from 0 °C to maximum levels at 8 °C, while the growth rates of P. antarctica only increased from 0 to 2 °C. The maximum thermal limits of P. subcurvata and P. antarctica where growth stopped completely were 14 and 10 °C, respectively. Although P. subcurvata outgrew P. antarctica at both temperatures in the co-incubation experiment, this happened much faster at 6 than at 0 °C. For P. subcurvata, there was a significant interactive effect in which the warmer temperature decreased the CO2 half-saturation constant for growth, but this was not the case for P. antarctica. The growth rates of both species increased with CO2 increases up to 425 ppm, and in contrast to significant effects of temperature, the effects of CO2 increase on their elemental composition were minimal. Our results suggest that future warming may be more favorable to the diatom than to the prymnesiophyte, while CO2 increases may not be a major factor in future competitive interactions between Pseudo-nitzschia subcurvata and Phaeocystis antarctica in the Ross Sea.

  6. Individual and interactive effects of warming and CO2 on Pseudo-nitzschia subcurvata and Phaeocystis antarctica, two dominant phytoplankton from the Ross Sea, Antarctica

    Directory of Open Access Journals (Sweden)

    Z. Zhu

    2017-11-01

    Full Text Available We investigated the effects of temperature and CO2 variation on the growth and elemental composition of cultures of the diatom Pseudo-nitzschia subcurvata and the prymnesiophyte Phaeocystis antarctica, two ecologically dominant phytoplankton species isolated from the Ross Sea, Antarctica. To obtain thermal functional response curves, cultures were grown across a range of temperatures from 0 to 14 °C. In addition, a co-culturing experiment examined the relative abundance of both species at 0 and 6 °C. CO2 functional response curves were conducted from 100 to 1730 ppm at 2 and 8 °C to test for interactive effects between the two variables. The growth of both phytoplankton was significantly affected by temperature increase, but with different trends. Growth rates of P. subcurvata increased with temperature from 0 °C to maximum levels at 8 °C, while the growth rates of P. antarctica only increased from 0 to 2 °C. The maximum thermal limits of P. subcurvata and P. antarctica where growth stopped completely were 14 and 10 °C, respectively. Although P. subcurvata outgrew P. antarctica at both temperatures in the co-incubation experiment, this happened much faster at 6 than at 0 °C. For P. subcurvata, there was a significant interactive effect in which the warmer temperature decreased the CO2 half-saturation constant for growth, but this was not the case for P. antarctica. The growth rates of both species increased with CO2 increases up to 425 ppm, and in contrast to significant effects of temperature, the effects of CO2 increase on their elemental composition were minimal. Our results suggest that future warming may be more favorable to the diatom than to the prymnesiophyte, while CO2 increases may not be a major factor in future competitive interactions between Pseudo-nitzschia subcurvata and Phaeocystis antarctica in the Ross Sea.

  7. Individual and interactive effects of warming and CO2 on Pseudo-nitzschia subcurvata and Phaeocystis antarctica, two dominant phytoplankton from the Ross Sea, Antarctica

    OpenAIRE

    Z. Zhu; P. Qu; J. Gale; F. Fu; D. A. Hutchins

    2017-01-01

    We investigated the effects of temperature and CO2 variation on the growth and elemental composition of cultures of the diatom Pseudo-nitzschia subcurvata and the prymnesiophyte Phaeocystis antarctica, two ecologically dominant phytoplankton species isolated from the Ross Sea, Antarctica. To obtain thermal functional response curves, cultures were grown across a range of temperatures from 0 to 14 °C. In addition, a co-culturing experiment examined the relative abundance of b...

  8. Examining the interactive effects of ocenaographic and anthropogenic influences with the SST anomaly, or Warm Blob on the bloom response of the toxigenic HAB genus Pseudo-nitzschia in the Santa Barbara Channel.

    Science.gov (United States)

    Amiri, S.

    2016-12-01

    Harmful algal blooms (HAB's) include a large subset of toxigenic phytoplankton and microbial species responsible for shutting down major fisheries, impairing water quality and threatening public health. Oceanographic and anthropogenic effects on HAB's in concert with climactic stressors may have interactive effects influencing HAB blooms to persist longer than historically documented. This 3 year time-series explores the interactive effects of the SST anomaly known as the Warm Blob across the coastal Pacific on the bloom progression and persistence of the toxigenic Pseudo-nitzschia bloom across the West Coast, ranging from the gulf of Alaska to the Santa Barbara Channel (SBC). This study also explores direct links of the Warm Blob event on nutrient and oxygen concentrations spatially across the Santa Barbara Channel with the highest levels of domoic acid concentrations recorded from the coast wide mega bloom. MODIS and SeaWIFS Satellite imagery of chlorophyll and SST monthly averaged values of the SBC were identified to better understand the regional distribution of the Warm Blob on phytoplankton community structure. These images were ground truthed with monthly samples from 7 transects across the SBC with the Plumes and Blooms time-series, LTER sites and local pier sites across the Santa Barbara County. Preliminary data suggest an interesting correlation with Pseudo-nitzschia species outcompeting other phytoplankton species within the SBC during the 3 degree averaged increase of SST conditions with the Warm Blob event. *Data is still being processed and results should be analyzed before October 2016.

  9. A Checklist of Navicula (Class Bacillariophyceae of the Philippines

    Directory of Open Access Journals (Sweden)

    Milagrosa Martinez-Goss

    2001-06-01

    Full Text Available A unified acocunt of all known diatoms in the genus Navicula, class Bacillariophyceae, of the Philippines from 1886 to 1987 is presented. A total of 226 taxa are listed. Included herewith are the references that originally described or cited the taxon and the ecological/habitat records for each taxon. As much as possible, a list of exsciccata materials is given together with their repository places.

  10. Morphology and taxonomy of an almost forgotten fossil diatom Gaillonella sculpta EHRENBERG (Bacillariophyceae)

    Czech Academy of Sciences Publication Activity Database

    Usoltseva, M.; Houk, Václav

    2016-01-01

    Roč. 31, č. 1 (2016), s. 39-49 ISSN 0269-249X Institutional support: RVO:67985939 Keywords : Miocene * Gaillonella * Pseudoaulacosira * taxonomy * valve ultrastructure. * Bacillariophyceae Subject RIV: EF - Botanics Impact factor: 1.677, year: 2016

  11. Distribution of diatom Pseudo-nitzschia and dinoflagellates of Dinophysis spp along coast off Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Alkawri, A.A.S.; Ramaiah, N.

    , 32 (1) 65-70 (2011) © Triveni Enterprises, Lucknow (India) For personal use only Free paper downloaded from: www. jeb. co. in commercial distribution of this copy is illegal Journal of Environmental Biology circleshadowdwnJanuary 2011circleshadowdwn... attain high cell numbers. It is reasonable for us to therefore caution that the toxic species do prevail in these waters. Key words Toxic phytoplankton, Diatom, Dinoflagellates, West coast of India Publication Data Paper received: 07 December 2009...

  12. Species of Mastogloia (Bacillariophyceae new for the Aegean coast of Turkey

    Directory of Open Access Journals (Sweden)

    F. COLAK SABANCI

    2013-03-01

    Full Text Available This paper describes the comprehensive morphological characteristics of ten Mastogloia Thwaites ex W. Smith (Bacillariophyceae species, including, M. aquilegiae, M. baldjikiana, M. binotata, M. grunowii, M. ignorata, M. paradoxa, M. pumila, M. cf. regula, M. similis and M. vasta. Specimens were examined under the light microscope; eight of them are reported for the first time from Turkish coastal waters. Apart from the photo documentation, some information on the species geographical distribution patterns and the type of the substratum are also provided.

  13. Xanthophyll cycle activity and photosynthesis of Dunaliella tertiolecta (Chlorophyceae) and Thalassiosira weissflogii (Bacillariophyceae) during fluctuating solar radiation

    NARCIS (Netherlands)

    van de Poll, Willem H.; Buma, Anita G. J.; Visser, Ronald J. W.; Janknegt, Paul J.; Villafane, Virginia E.; Helbling, E. Walter

    Short-term ultraviolet (UV) radiation (280-400 nm) effects on xanthophyll cycle activity and photosynthesis were assessed during fluctuating irradiance (60- and 10-min cycles - saturating irradiance to near-zero irradiance) for the marine algae Thalassiosira (Bacillariophyceae) and Dunaliella

  14. Dangerous relations in the Arctic marine food web: Interactions between toxin producing Pseudo-nitzschia diatoms and Calanus copepodites

    DEFF Research Database (Denmark)

    Hardardottir, Sara; Pancic, Marina; Tammilehto, Anna

    2015-01-01

    %) suggesting the response to be chemically mediated. The induced response was also triggered when copepodites grazed on another diatom, supporting the hypothesis that the cues originate from the copepodite. Neither pH nor nutrient concentrations explained the induced DA production. Unexpectedly, P. obtusa also...

  15. Higher ribosomal RNA substitution rates in Bacillariophyceae and Dasycladales than in Mollusca, Echinodermata, and Actinistia-Tetrapoda.

    Science.gov (United States)

    Sorhannus, U

    1996-09-01

    Molecular evolutionary rates within two protistan and three metazoan taxa were estimated using divergence times derived from fossil records. The results indicate that the small-subunit rRNA sequences within Dasycladales (Chlorophyta) and Bacillariophyceae evolved at a rate approximately two to three times faster than that estimated within Echinodermata, Mollusca, and Actinistia-Tetrapoda. It was concluded that this twofold discrepancy demonstrates actual taxonomic differences in the fixation rate of mutations in the small-subunit rRNA.

  16. Diatoms (Bacillariophyceae of Iguaçu National Park, Foz do Iguaçu, Brazil

    Directory of Open Access Journals (Sweden)

    Elaine Cristina Rodrigues Bartozek

    2013-03-01

    Full Text Available This study represents a taxonomic survey of class Bacillariophyceae diatoms found in samples collected in the Iguaçu River (Iguaçu National Park, municipality of Foz do Iguaçu, in the state of Paraná, Brazil between August 2007 and July 2008. Two sampling stations were utilized, the first located upstream of Iguaçu Falls (Cais Bananeiras Station and second downstream of the falls (Cais Macuco Safari Station. The study resulted in the identification of 86 taxa, including 74 at the specific level and seven taxonomic varieties. Two of these had never before been documented in the state of Paraná: Gomphonema gibberum Hustedt and Pinnularia meridiana Metzeltin & Krammer. Nine are first-time records for Brazil: Cymbella charrua Metzeltin, Lange-Bertalot & García-Rodríguez, Placoneis ovillus Metzeltin, Lange-Bertalot & García-Rodríguez, Gomphonema affinopsis Metzeltin, Lange-Bertalot & García-Rodríguez, , Gomphosphenia lingulatiformis (Lange-Bertalot & Reichardt Lange-Bertalot, Luticola aequatorialis (Heiden Lange-Bertalot & Ohtsuka, Sellaphora garciarodriguezii Metzeltin & Lange-Bertalot, Eolimna submuralis (Hustedt Lange-Bertalot Kulikovskiy, Geissleria neosubtropica Metzeltin, Lange-Bertalot & García-Rodríguez and Stauroneis cf. sylviabonillae Metzeltin, Lange-Bertalot & García-Rodríguez.

  17. Epilithic diatoms (Bacillariophyceae from running watersin NW Iberian Peninsula (Galicia, Spain

    Directory of Open Access Journals (Sweden)

    Manel Leira

    2017-12-01

    Full Text Available A catalog of Bacillariophyceae for the rivers of NW of Spain is made for the first time. It includes a re-examination of the taxa reported in previous publications, taxa cited during the last years of the rivers of the Galicia-Costa Hydrographic Demarcation, and a revision of the taxonomy, in line with the systematic and nomenclature changes, which have occurred mainly in recent years. The epilethic diatoms of the river basins of Galicia-Costa were sampled during the years 2005, 2006, and 2007, in May-June and September. The study was carried out in 41 localities distributed along 31 rivers, samples were taken in upstream and downstream sections. Diatom communities were compared in all upstream sections of these rivers draining from siliceous substrates. We identified 141 taxa of diatoms from the coast of Galicia. In this paper we present 15 new citations for Galicia, two for Spain and three for the Iberian Peninsula, in addition to a new species recently described. The dominant taxa are: Achnanthidium minutissimum, Achnanthes subhudsonis, Karayevia oblongella, Cocconeis placentula var. euglypta, Gomphonema rhombicum, and Navicula minima. Achnanthes subhudsonis was the most abundant species during the spring and summer months. The remaining species showed no relevant changes regardless of the time of year. The results indicate that the river diatoms of Galicia are an important component of the diversity of the ecosystem.

  18. Atıksu Arıtma Tesisinin Diyatom (Bacillariophyceae Tür Komposizyonuna Etkileri.

    Directory of Open Access Journals (Sweden)

    Fatma Çolak Sabancı

    2015-12-01

    Full Text Available Ege denizi’nin ötrofik körfezi olan İzmir Körfezi’nin fitoplankton tür komposizyonu 1998-2000-2001 ve 2002 yıllarında iç, orta, dış körfezde yer alan 14 istasyonda mevsimsel ve kalitatif olarak incelendi. Bu araştırmanın sonuçlarına göre, İzmir Körfezi’nde Cyanophyceae, Dinophyceae, Dictyochophyceae, Bacillariophyceae olmak üzere 4 alg sınıfı ve Ciliata olmak üzere bir protozooplankton sınıfına ait türler saptanmıştır. Bu sınıflar içersinde tür sayısı bakımından Dinophyceae sınıfının diğer sınıflara oranla daha baskın olduğu bulunmuştur. Çiğli Atık Su Arıtma Tesisi ünitesinin 2000 yılının sonlarında devreye girmesini takiben tür çeşitliliğinde önemli düzeyde değişimler olduğu saptandı. Saptanan türlerin kalitatif tür matrisi üzerinde gerçekleştirilen hiyerarşik kümelendirme ve çok boyutlu ölçeklendirme analizlerinin sonuçlarına göre, tür assosiyasyonlarının belirlenmesi ve istasyonlar arasındaki benzerliklerin çıkartılması amaçlandı

  19. Diatoms from the Colombian and Peruvian Amazon: the Genera Encyonema, Encyonopsis and Gomphonema (Cymbellales: Bacillariophyceae

    Directory of Open Access Journals (Sweden)

    Amelia A Vouilloud

    2010-03-01

    Full Text Available Diatoms from the Colombian and Peruvian Amazon: the Genera Encyonema, Encyonopsis and Gomphonema (Cymbellales, Bacillariophyceae. The diatom flora of the Colombian and Peruvian Amazon is far less studied than the flora of the Brazilian sector of the basin. Here we present results related to the genera Encyonema, Encyonopsis and Gomphonema. Plankton and periphyton samples were collected in lotic and lentic waterbodies from the Amazonian-Andean region, the Amazon River, Japurá River and Porvenir River basins during 1993, 1994, 2001 and 2003. At each sampling station pH, temperature, water transparency and conductivity were registered. Samples were analyzed with phase contrast microscope (LM and scanning electron microscope (SEM. Ten taxa are new records for the area; Encyonema for the Peruvian and Colombian Amazon and Encyonopsis for the Colombian Sector. Encyonema neogracile var. tenuipunctatum, E. vulgare, Encyonopsis frequentis, Gomphonema augur var. sphaerophorum and G. contraturris are recorded for the first time in Colombia; Encyonema venezolanum and G. neoapiculatum in Colombia and Peru and the latter also for Amazonia. E. angustecapitatum was mentioned in Colombia before at a pond located at 3000m asl. We describe a new species from Porvenir River, Amazonas, Colombia: Encyonema amazonianum. Rev. Biol. Trop. 58 (1: 45-62. Epub 2010 March 01.La flora diatomológica de la Amazonia Colombiana y Peruana está mucho menos estudiada que la flora del sector brasilero. Se presentan los resultados de los géneros Encyonema, Encyonopsis y Gomphonema. Muestras de plancton y perifiton fueron colectadas en ambientes lóticos y lénticos de la región amazónica-andina, en los ríos Amazonas, Japurá y Porvenir durante 1993, 1994, 2001 y 2003. En cada estación de muestreo se realizaron mediciones de pH, temperatura, transparencia del agua y conductividad. Las muestras fueron analizadas con microscopio óptico con contraste de fases y microscopio electr

  20. New Design Strategy for Development of Specific Primer Sets for PCR-Based Detection of Chlorophyceae and Bacillariophyceae in Environmental Samples▿ †

    OpenAIRE

    Valiente Moro, Claire; Crouzet, Olivier; Rasconi, Séréna; Thouvenot, Antoine; Coffe, Gérard; Batisson, Isabelle; Bohatier, Jacques

    2009-01-01

    Studying aquatic microalgae is essential for monitoring biodiversity and water quality. We designed new sets of 18S rRNA PCR primers for Chlorophyceae and Bacillariophyceae by using the ARB software and implementing a virtual PCR program. The results of specificity analysis showed that most of the targeted algal families were identified and nontargeted organisms, such as fungi or ciliates, were excluded. These newly developed PCR primer sets were also able to amplify microalgal rRNA genes fro...

  1. DIATOMS (BACILLARIOPHYCEAE IN RIVERS AND STREAMS AND ON CULTIVATED SOILS OF THE PODKARPACIE REGION IN THE YEARS 2007–2011

    Directory of Open Access Journals (Sweden)

    Teresa Noga

    2014-01-01

    Full Text Available Diatoms Bacillariophyceae are a specialized, systematic group of algae, living in different types of ecosystems, and they are very good indicators of water quality. Recently, detailed studies have been carried out in the territory of the Podkarpacie Province on the diversity of diatoms in running waters. The area of study covers mostly the catchment of the biggest rivers of the province (mainly the River Wisłok and cultivated soils. Running waters in the Podkarpacie Province are characterized by a huge species richness of diatoms, 738 different taxa have been found so far. The highest number of taxa was noted in the Wisłok River (400, while the Żołynianka and Różanka streams and the Mleczka were also characterized by huge diversity (from 200 to over 350 taxa. In the majority of studied sites diatoms of alkaline (pH>7 and nutrient rich (eutrophic waters dominated: Navicula lanceolata, N. gregaria, N. capitatoradiata, Nitzschia palea, N. dissipata ssp. dissipata, Achnanthidium minutissimum var. minutissimum, A. pyrenaicum, Amphora pediculus, Diatoma vulgaris, Rhoicosphenia abbreviata, Planothidium lanceolatum, Cocconeis pediculus and C. placentula var. lineata. About 150 taxa were indentified on cultivated soils, among which the largest populations were formed by Hantzschia amphioxys, Mayamaea atomus, Nitzschia palea, N. pusilla, Pinnularia obscura and Stauroneis thermicola.

  2. New design strategy for development of specific primer sets for PCR-based detection of Chlorophyceae and Bacillariophyceae in environmental samples.

    Science.gov (United States)

    Moro, Claire Valiente; Crouzet, Olivier; Rasconi, Séréna; Thouvenot, Antoine; Coffe, Gérard; Batisson, Isabelle; Bohatier, Jacques

    2009-09-01

    Studying aquatic microalgae is essential for monitoring biodiversity and water quality. We designed new sets of 18S rRNA PCR primers for Chlorophyceae and Bacillariophyceae by using the ARB software and implementing a virtual PCR program. The results of specificity analysis showed that most of the targeted algal families were identified and nontargeted organisms, such as fungi or ciliates, were excluded. These newly developed PCR primer sets were also able to amplify microalgal rRNA genes from environmental samples with accurate specificity. These tools could be of great interest for studying freshwater microalgal ecology and for developing bioindicators of the health status of aquatic environments.

  3. New Design Strategy for Development of Specific Primer Sets for PCR-Based Detection of Chlorophyceae and Bacillariophyceae in Environmental Samples▿ †

    Science.gov (United States)

    Valiente Moro, Claire; Crouzet, Olivier; Rasconi, Séréna; Thouvenot, Antoine; Coffe, Gérard; Batisson, Isabelle; Bohatier, Jacques

    2009-01-01

    Studying aquatic microalgae is essential for monitoring biodiversity and water quality. We designed new sets of 18S rRNA PCR primers for Chlorophyceae and Bacillariophyceae by using the ARB software and implementing a virtual PCR program. The results of specificity analysis showed that most of the targeted algal families were identified and nontargeted organisms, such as fungi or ciliates, were excluded. These newly developed PCR primer sets were also able to amplify microalgal rRNA genes from environmental samples with accurate specificity. These tools could be of great interest for studying freshwater microalgal ecology and for developing bioindicators of the health status of aquatic environments. PMID:19592531

  4. Finding a partner in the ocean: molecular and evolutionary bases of the response to sexual cues in a planktonic diatom.

    Science.gov (United States)

    Basu, Swaraj; Patil, Shrikant; Mapleson, Daniel; Russo, Monia Teresa; Vitale, Laura; Fevola, Cristina; Maumus, Florian; Casotti, Raffaella; Mock, Thomas; Caccamo, Mario; Montresor, Marina; Sanges, Remo; Ferrante, Maria Immacolata

    2017-07-01

    Microalgae play a major role as primary producers in aquatic ecosystems. Cell signalling regulates their interactions with the environment and other organisms, yet this process in phytoplankton is poorly defined. Using the marine planktonic diatom Pseudo-nitzschia multistriata, we investigated the cell response to cues released during sexual reproduction, an event that demands strong regulatory mechanisms and impacts on population dynamics. We sequenced the genome of P. multistriata and performed phylogenomic and transcriptomic analyses, which allowed the definition of gene gains and losses, horizontal gene transfers, conservation and evolutionary rate of sex-related genes. We also identified a small number of conserved noncoding elements. Sexual reproduction impacted on cell cycle progression and induced an asymmetric response of the opposite mating types. G protein-coupled receptors and cyclic guanosine monophosphate (cGMP) are implicated in the response to sexual cues, which overall entails a modulation of cell cycle, meiosis-related and nutrient transporter genes, suggesting a fine control of nutrient uptake even under nutrient-replete conditions. The controllable life cycle and the genome sequence of P. multistriata allow the reconstruction of changes occurring in diatoms in a key phase of their life cycle, providing hints on the evolution and putative function of their genes and empowering studies on sexual reproduction. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  5. Coscinodiscophyceae, Fragilariophyceae e Bacillariophyceae (Achnanthales dos rios Ivaí, São João e dos Patos, bacia hidrográfica do rio Ivaí, município de Prudentópolis, PR, Brasil Coscinodiscophyceae, Fragilariophyceae and Bacillariophyceae (Achnanthales of the Ivaí, São João and Patos rivers in the Ivaí basin, Prudentópolis, Paraná State, Brazil

    Directory of Open Access Journals (Sweden)

    Fernanda Ferrari

    2007-06-01

    Full Text Available Realizou-se o levantamento florístico das Coscinodiscophyceae, Fragilariophyceae e Bacillariophyceae (Achnanthales dos rios Ivaí, São João e dos Patos, pertencentes à bacia hidrográfica do rio Ivaí, município de Prudentópolis, Paraná. Quarenta e uma amostras foram coletadas em março, junho e julho/2002 e janeiro/2003, e analisadas. As coletas fitoplanctônicas foram feitas através de arrasto superficial com rede de plâncton (25 µm e as perifíticas através da coleta de porções submersas de macrófitas aquáticas, rochas, cascalho, sedimento ou substrato arenoso. Foram identificados, nove táxons pertencentes à classe Coscinodiscophyceae, oito à classe Fragilariophyceae e quinze à ordem Achnanthales (Bacillariophyceae. Thalassiosira weissflogii (Grunow Fryxell & Hasle, Achnanthidium sp., Planothidium biporomum (Hohn & Hellerman Lange-Bertalot e Cocconeis placentula var. pseudolineata Geitler consistiram em novas citações para o estado do Paraná.A floristic study of Coscinodiscophyceae, Fragilariophyceae and Bacillariophyceae (Achnanthales in the Ivaí, São João and Patos rivers from the upper Ivaí river basin, located at Prudentópolis, Paraná State, Brazil is presented. Forty-one samples were collected in March, June and July/2002 and January/2003, and analysed. Phytoplankton samples were collected with a plankton net (25 µm mesh; periphyton was collected by removing the attached material from submerged portions of aquatic macrophytes, rocks, sediment or the sandy substratum. Nine species of the class Coscinodiscophyceae, eight of the class Fragilariophyceae and fourteen of the order Achnanthales were identified. Thalassiosira weissflogii (Grunow Fryxell & Hasle, Achnanthidium sp., Planothidium biporomum (Hohn & Hellerman Lange-Bertalot and Cocconeis placentula var. pseudolineata Geitler were new diatom records for Paraná State.

  6. Phytoplankton dynamics with a special emphasis on harmful algal blooms in the Mar Piccolo of Taranto (Ionian Sea, Italy).

    Science.gov (United States)

    Caroppo, Carmela; Cerino, Federica; Auriemma, Rocco; Cibic, Tamara

    2016-07-01

    The response of phytoplankton assemblages to the closure of urban sewage outfalls (USOs) was examined for the Mar Piccolo of Taranto (Mediterranean Sea), a productive semi-enclosed coastal marine ecosystem devoted to shellfish farming. Phytoplankton dynamics were investigated in relation to environmental variables, with a particular emphasis on harmful algal blooms (HABs). Recent analyses evidenced a general reduction of the inorganic nutrient loads, except for nitrates and silicates. Also phytoplankton biomass (chlorophyll a) and abundances were characterized by a decrease of the values, except for the inner area of the basin (second inlet). The phytoplankton composition changed, with nano-sized species, indicators of oligotrophic conditions, becoming dominant over micro-sized species. If the closure of the USOs affected phytoplankton dynamics, however, it did not preserve the Mar Piccolo from HABs and anoxia crises. About 25 harmful species have been detected throughout the years, such as the potentially domoic acid producers Pseudo-nitzschia cf. galaxiae and P seudo-nitzschia cf. multistriata, identified for the first time in these waters. The presence of HABs represents a threat for human health and aquaculture. Urgent initiatives are needed to improve the communication with authorities responsible for environmental protection, economic development, and public health for a sustainable mussel culture in the Mar Piccolo.

  7. Skeletonema (Bacillariophyceae) in Indian waters: A reappraisal

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, R.K.; Sarno, D.; Kooistra, W.H.C.F.; DeCosta, P.M.; Anil, A.C.

    observed the species as live material. Results of the molecular identification procedure showed that the partial LSU rDNA sequence of the culture strain was identical to those of S. costatum strains B and C (Lagoa dos Patos, Brazil, Genbank numbers...

  8. Distribution patterns and biomass estimates of diatoms and autotrophic dinoflagellates in the NE Atlantic during June and July 1996

    Science.gov (United States)

    Yallop, M. L.

    Qualitative and quantitative analyses of microphytoplankton communities were determined from samples collected in the northeast Atlantic Ocean in the early summer of 1996 during the PRIME Cruise of the RRS Discovery. A combination of light microscopy and scanning electron microscopy techniques was used to determine the species composition of two of the main groups of phytoplankton: Bacillariophyceae and Dinophyta. Two series of samples were collected; the first set of samples was collected between 18 and 29 June 1996 during a Lagrangian time-series study in the vicinity of 59°N 20°W tracking a mesoscale cold-core eddy; the second set of samples was collected between 4 and 10 July 1996 during a transect along the 20°W meridian from 59 to 37°N. A total of 155 samples were analysed over various depths down to 150 m, and 78 phytoplankton species were identified. Samples taken during the Lagrangian time-series study were dominated by diatom species, including Ephemera planamembranacea and Pseudo-nitzschia species, whilst the main representative of the microphytoplankton dinoflagellates was Ceratium fusus. On the transect, several Ceratium species were common, including C. furca C. fusus, and C. lineatum, and three other autotrophic dinoflagellates were frequent including Prorocentrum minimum, Oxytoxum scolopax and Gonyaulax polygramma. A number of diatoms dominated the profiles along the transect including Leptocylindrus mediterraneus, Thalassiosira oestrupii, and representatives of the genera Haslea and Pseudo-nitzschia. Standing stocks of both groups were low and typical of post-bloom carbon levels. Diatom biomass exceeded that of dinoflagellate biomass in the eddy although the reverse situation was seen in the more southerly stations along the transect. Maximum abundances of the dinoflagellate communities were situated in the surface waters within the mixed layer, while depth maxima of certain diatoms were noted at around 40 m below the depth of the mixed layer

  9. Bacillariophyceae del complejo lagunar Vilama (Jujuy, Argentina Bacillariophyceae of Vilama lacustrine system (Jujuy Argentina

    Directory of Open Access Journals (Sweden)

    Nora I. Maidana

    2009-12-01

    Full Text Available Con el objetivo general de continuar con el relevamiento de la flora diatomológica en cuerpos de agua de alta montaña, en enero de 2005 se obtuvieron muestras de agua de 12 humedales del Complejo Lagunar Vilama (4500 m snm en la provincia de Jujuy. Con esta contribución se incrementa el conocimiento de la flora de diatomeas para este tipo de ambientes. Se identificaron un total de 43 géneros y 137 taxones infragenéricos, de los cuales 6 son mencionados por primera vez para el país y se describe una especie nueva Staurophora vilamae. Se discute también la relación entre la riqueza de especies con algunas características ambientales.The aim of this paper is to continue the diatom flora survey in high mountain water bodies. There have been obtained, in January 2005, water samples from 12 wetlands (4500 m asl in the Vilama lacustrine system, Jujuy province. With this contribution, the knowledge of the diatom flora in this type of environments is increased. There have been identified 43 genera and 137 infrageneric taxa of wich six are mentioned by the first time for the country and one new species, Staurophora vilamae was described. The relation between species richness and some environmental parameters is also discussed.

  10. Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific

    National Research Council Canada - National Science Library

    Mary W. Silver; Sibel Bargu; Susan L. Coale; Claudia R. Benitez-Nelson; Ana C. Garcia; Kathryn J. Roberts; Emily Sekula-Wood; Kenneth W. Bruland; Kenneth H. Coale; M. M. Morel

    2010-01-01

    ...°S) contain the neurotoxin domoic acid (DA), associated with the diatom Pseudo-nitzschia. Of the 35 stations sampled, including ones from historic iron fertilization experiments (SOFeX, IronEx II...

  11. The seasonal changes of diatom species composition and species diversity in Izmir Bay between 2008-

    Directory of Open Access Journals (Sweden)

    Fatma Çolak Sabancı

    2015-12-01

    Full Text Available Bu araştırmada diyatom tür komposizyonu ve tür çeşitliliği (Shannon-Wiener değişimleri, iç, orta, dış körfezde yer alan 9 istasyonda (0.5 m, 5.0 m, 10.0 m ve 15.0 m kalitatif ve kantitatif olarak 2008-2010 yılları arasında mevsimsel olarak (Kasım 2008, Şubat 2009, Nisan 2009, Temmuz 2009, Kasım 2009, Şubat 2010, Mart 2010 ve Temmuz 2010 incelendi. Yapılan çalışmalar sonucunda Bacillariophyceae sınıfına ait toplam 29 cins, 48 tür, 1 varyete ve 3 forma saptanmış, istasyonlara ve örnekleme periyoduna bağlı olarak diyatom yoğunluğunda farklar belirlenmiştir. Aşırı üremeler özellikle iç körfezde bulunan istasyonlarda Şubat 2009 ve 2010 dönemlerinde gözlenmiş ve en yüksek hücre yoğunluğu İstasyon 26’da saptanmıştır, istasyon 22 ve istasyon 24, istasyon 26’yı izlemektedir. Bacillariophyceae türleri hücre yoğunluklarındaki katkılar incelendiğinde Pseudo-nitzschia pungens, Rhizosolenia setigera ve Skeletonema costatum baskınlığı nedeniyle sorumlu türlerdir. Bununla birlikte, Pleurosigma elongatum nisbi bolluğu ve bulunma sıklığı en fazla olan türdür. En yüksek diversite indeks değeri 35 tür ile Şubat 2009 döneminde 4.778 bits hücre-1, en düşük diversite indeks değeri ise 31 tür ile Temmuz 2009 döneminde 0.963 bits hücre-1 olarak saptanmıştır

  12. Life cycle size dynamics in Didymosphenia geminata (Bacillariophyceae).

    Science.gov (United States)

    Bishop, Ian W; Spaulding, Sarah A

    2017-06-01

    Didymosphenia geminata has received a great deal of attention in the last 25 years, and considerable effort has gone into determining the origin, ecological impact, and economic consequences of its invasive behavior. While environmental conditions are a controlling influence in distribution, the extreme success of the species may be tied to its basic biology and life history. Little is known, however, about population dynamics, size restoration and reproduction of D. geminata. The objective of this study was to determine the temporal patterns in cell size frequency, size restoration strategy, and synchronization of life cycles between populations in close proximity. We implemented FlowCam technology to measure the length of more than 100,000 D. geminata cells from two sites in South Boulder Creek, Colorado over 1 year. We applied finite mixture modeling to uncover temporal patterns in size distribution. Our results show that collections of D. geminata exhibited a complex, multimodal size distribution, almost always containing four overlapping age cohorts. We failed to observe direct visual evidence of the sexual phase. Multiple abrupt and directional shifts in size distribution, however, were documented providing conclusive evidence of cell size restoration. Lastly, nodules in close proximity were asynchronous with respect to size frequency profiles and size diminution, highlighting the relevance of spatial heterogeneity in in situ diatom size dynamics. This study is the first to document the complexity of diatom cell size distribution in a lotic system, size restoration in D. geminata, and the variability in rates of size reduction at microhabitat spatial scales. © 2017 Phycological Society of America.

  13. Four new freshwater diatom species (Bacillariophyceae) from Antarctica

    Czech Academy of Sciences Publication Activity Database

    Zidarova, R.; Van de Vijver, B.; Mataloni, G.; Kopalová, K.; Nedbalová, Linda

    2009-01-01

    Roč. 30, č. 4 (2009), s. 295-310 ISSN 0181-1568 Institutional research plan: CEZ:AV0Z60050516 Keywords : Antarctica * diatoms * James Ross Island Subject RIV: EF - Botanics Impact factor: 0.574, year: 2009

  14. Nuevos registros de Diatomeas (Bacillariophyceae de la Amazonia Colombiana

    Directory of Open Access Journals (Sweden)

    Sala Silvia Estela

    1999-06-01

    Full Text Available Ten diatom taxa are recorded for the first time from the Colombian Amazon basin, in the genera Cyclotella (1, Aulacoseira (2, Achnanthes (1, Lemnicola (1, Amphipleura (1, Gyrosigma (1, Stauroneis (1, Hantzschia (1 and Nitzschia (1. Four of these, Aulacoseira granulata var. angustissima, Achnanthes intlete, Gyrosigma spencerii, and Stauroneis phoenicenteron, are recorded for the first time in Colombia. Details of the valve morphology for five taxa are discussed.Se citan diez taxones de diatomeas por primera vez para la Amazonia colombiana. Los taxones pertenecen a los géneros Cyclotella (1, Aulacoseira (2, Achnanthes (1, Lemnicola (1, Amphipleura (1, Gyrosigma (1, Stauroneis (1, Hantzschia (1 Y Nitzschia (1. Cuatro de ellos, Aulacosiera granulata var. anqustissima, Achnanthes inflata, Gyrosigma spencerii y Stauroneis phoenicenteron se registran por primera vez en Colombia. Se discute la morfología valvar de cinco de las especies tratadas.

  15. La familia Hemiaulaceae (Bacillariophyceae de las aguas marinas chilenas The family Hemiaulaceae (Bacillariophyceae from marine Chilean waters

    Directory of Open Access Journals (Sweden)

    PATRICIO RIVERA

    2003-12-01

    Full Text Available La familia Hemiaulaceae comprende cuatro géneros, señalados previamente para las aguas chilenas con las siguientes especies: Cerataulina pelagica (Cleve Hendey, Hemiaulus sinensis Greville, H. membranaceus Cleve, Climacodium biconcavum Cleve, Eucampia antarctica (Castracane Mangin, E. cornuta (Cleve Grunow y E. zodiacus Ehrenberg. Sin embargo, el análisis con microscopía fotónica y electrónica de muestras recolectadas en aguas marinas chilenas que contenían representantes de esta familia (incluyendo la mayoría de aquellas estudiadas anteriormente por otros investigadores nacionales reveló que (1 el género Cerataulina está representado por C. pelagica, distribuida a lo largo de la costa chilena entre Arica por el norte y el Estrecho de Magallanes por el sur, (2 el género Eucampia está representado por cuatro taxa: E. zodiacus f. cylindrocornis Syvertsen (señalada en trabajos anteriores como E. zodiacus f. zodiacus, E. zodiacus f. recta Rivera. Avaria & Cruces f. nov. (descrita aquí, E. cornuta y E. antarctica. Los primeros tres taxa se distribuyen en la zona central y norte de Chile, mientras que E. antarctica es propia de las aguas antárticas desde el Estrecho de Magallanes al sur, (3 las citas anteriores de Hemiaulus sinensis, H. membranaceus y Climacodium biconcavum para las aguas chilenas corresponden a determinaciones erróneas de Eucampia zodiacus f. recta, f. nov. Se entregan descripciones de los taxa encontrados y fotografías obtenidas con los microscopios fotónico y electrónicos que ilustran sus principales características morfológicasThe Family Hemiaulaceae comprises four genera, all of which have been previously reported for coastal waters off Chile, and represented by the following taxa: Cerataulina pelagica (Cleve Hendey, Hemiaulus sinensis Greville, H. membranaceus Cleve, Climacodium biconcavum Cleve, Eucampia antarctica (Castracane Mangin, E. cornuta (Cleve Grunow and E. zodiacus Ehrenberg. However, examination with light and electron microscopy of marine samples from along the Chilean coast and the Antarctic Peninsula (including those used in earlier publications revealed that (1 the genus Cerataulina is represented by C. pelagica, and is distributed along the Chilean coast between Arica in the north and the Magellan Strait in the south, (2 the genus Eucampia comprises four taxa: E. zodiacus f. cylindrocornis Syvertsen (previously reported for Chile as E. zodiacus f. zodiacus, E. zodiacus f. recta Rivera, Avaria & Cruces (described here, E. cornuta and E. antarctica. The former three taxa occur in the central and northern coast of Chile, while E. antarctica lives in Antarctic waters south of the Magellan Strait, (3 earlier records of Hemialus membranaceus, H. sinensis and Climacodium biconcavum in Chilean waters are misidentifications of Eucampia zodiacus f. recta Rivera & Avaria f. nov. A short description is included for each taxon, and photographs provide information about the main morphological characteristics

  16. Calanus spp.-Vectors for the biotoxin, domoic acid, in the Arctic marine ecosystem?

    DEFF Research Database (Denmark)

    Tammilehto, A.; Nielsen, Torkel Gissel; Krock, B.

    2012-01-01

    Three Calanus species, Calanus glacialis, Calanus finmarchicus and Calanus hyperboreus, which are the most important zooplankton herbivores in Western Greenland, were fed with unialgal cultures of toxic Pseudo-nitzschia seriata and non-toxic Pseudo-nitzschia delicatissima. All three copepod species...... grazed on toxic P. seriata and also accumulated domoic acid during the grazing. There were no differences in ingestion rates between toxic and non-toxic Pseudo-nitzschia species in any of the copepods. C. finmarchicus and C. hyperboreus grazed on toxic P. seriata during the first 6 h of the experiment...... but seemed to stop grazing during the last 6 h of the experiment suggesting that the copepods may have suffered some kind of physiological incapacitation due to ingestion of domoic acid. C. glacialis grazed on toxic P. seriata continuously during the whole experiment, probably due to the lower domoic acid...

  17. 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.

  18. El género Navicula sensu stricto (Bacillariophyceae en humedales de altura de Jujuy, Argentina The genus Navicula sensu stricto (Bacillariophyceae in highland wetlands of Jujuy, Argentina

    Directory of Open Access Journals (Sweden)

    Nora I. Maidana

    2011-06-01

    Full Text Available Aquí presentamos los resultados del estudio de la diversidad del género Navicula Bory en 22 humedales de altura de la provincia de Jujuy, Argentina (22° 30' - 22° 44' S; y 66° 39' - 66° 59' W; entre 3500 y 4683 m snm, incluyendo el Complejo Lagunar Vilama. Los ambientes con mayor riqueza de especies fueron las lagunas Vilama, Catal, Rincón de Cajas y Del Arenal, mientras que en la laguna Colorada el género estuvo ausente. Las especies con mayor frecuencia de ocurrencia fueron Navicula lauca Rumrich & Lange-Bertalot, N. paranicota Rumrich & Lange-Bertalot, N. salinicola Hustedt var. salinicola y N. veneta Kützing. En este trabajo discutimos algunos aspectos ecológicos, biogeográficos y taxonómicos y asignamos a una de las dos Secciones del género a las especies exclusivamente americanas. Con esta contribución ampliamos el conocimiento disponible sobre las diatomeas de ambientes de altura de Sudamérica.In this paper we present the main outcomes of the study of the diversity of genus Navicula Bory in 22 highland wetlands located in the Jujuy Province, Argentina (22° 30' - 22° 44' S; and 66° 39' - 66° 59' W; between 3500 and 4683 masl, including the Vilama Lake Complex. The environments with broader species richness were Vilama, Catal, Rincón de Cajas and Del Arenal, meanwhile in Laguna Colorada the genus was absent. The more frequent species were Navicula lauca Rumrich & Lange-Bertalot, N. paranicota Rumrich & Lange-Bertalot, N. salinicola Hustedt var. salinicola and N. veneta Kützing. We also discuss some ecological, bio-geographical and taxonomical issues and we assigned the exclusively American species to one of the two Sections of the genus. With the following contribution we improve the knowledge about the diatoms of highlands environments of Southamerica.

  19. Diatomeas (Bacillariophyceae de humedales de altura de la Provincia de Jujuy-Argentina Diatoms (Bacillariophyceae from high altitude wetlands of Jujuy province-Argentina

    Directory of Open Access Journals (Sweden)

    Claudia Seeligmann

    2008-07-01

    Full Text Available Se estudió la flora diatomológica perteneciente a 13 humedales de altura ubicados entre los 3500-4683 m s. n. m. de la Provincia de Jujuy (Argentina. Se identificaron, excluyendo las especies de Navicula sensu stricto, 51 géneros y 157 taxones infragenéricos, de los cuales tres son nuevas citas para Argentina y 43 se registran por primera vez para Jujuy. Se propone una nueva combinación: Craticula cuspidata var. gracilis. Muy interesante resultó el hallazgo de Cylindrotheca gracilis (Bréb. Grunow, nunca antes mencionado para este tipo de ambientes. Sólo Amphora veneta Kützing estuvo presente en más del 90 % de los cuerpos de agua estudiados mientras que Nitzschia hungarica Grunow, Craticula cuspidata (Kützing D. G. Mann var. cuspidata y Luticola cohnii (Hilse Lange-Bertalot fueron halladas en más del 60% de las muestras.A diatomological analysis of thirteen high altitude wetlands, between 3500-4683 m a. s. l. of Jujuy Province (Argentina was performed. Fifty one genera and one hundred and fifty seven infrageneric taxa, excluding Navicula sensu stricto species, were identified; three of them are new records for Argentina and 43 are new for Jujuy Province. A new combination is proposed: Craticula cuspidata var. gracilis. The finding of Cylindrotheca gracilis (Bréb. Grunow is important, since it has not been previously mentioned for this kind of environments. Amphora veneta Kützing var. veneta was recorded in more than 90 % of the studied waterbodies while Nitzschia hungarica Grunow, Craticula cuspidata (Kützing D. G. Mann var cuspidata and Luticola cohnii (Hilse Lange-Bertalot were found in more than 60% of the samples.

  20. Algal blooms in Nigerian waters: an overview | Akin-Oriola | African ...

    African Journals Online (AJOL)

    water bodies include cyanobacteria (Microcystis spp., Oscillatoria spp., Anabaena spp. and Trichodesmium thiebautii), diatoms (Pseudo-nitzschia spp., Nitzschia spp. and ... This paper reviews information on toxic microalgae in Nigerian waters and emphasises the need for monitoring and research efforts in the region.

  1. Modelling the influence of silicon and phosphorus limitation on the ...

    African Journals Online (AJOL)

    Pseudo-nitzschia seriata (Cleve) H. Peragallo isolated from Scottish west coast waters was studied in laboratory batch culture. The neurotoxin domoic acid was produced in both P- and Si-limited stationary phase, but in greater quantities when Si was the limiting nutrient. A mathematical model based on cell quota kinetics ...

  2. River and Submarine Groundwater Discharge Effects on Diatom Phytoplankton Abundance in the Gulf of Alaska

    Directory of Open Access Journals (Sweden)

    Alanna L. Lecher

    2017-12-01

    Full Text Available The Gulf of Alaska is a highly productive ecosystem that supports fisheries and subsistence harvesting of marine resources. The highly productive summer season begins with a bloom that is dominated by diatoms. Both river and submarine groundwater discharge have been recognized as substantial terrestrial nutrient (nitrate and silicate sources to the Gulf’s coastal waters. Here, the response of in-situ phytoplankton to groundwater and river water additions was evaluated via a bioassay incubation experiment. Special attention was given to diatom genera, as previous studies have shown that submarine groundwater discharge preferentially induces growth of diatoms. The abundance of Pseudo-nitzschia spp., Chaetoceros spp., and Leptocylindrus spp. increased significantly in groundwater and river water containing treatments. Although groundwater and river water are both rich in nitrate and silicate, groundwater treatments with a higher salinity favored a higher relative abundance of Pseudo-nitzschia spp. Conversely, in the highest river water concentration treatments with lower salinity, relative abundances of Pseudo-nitzschia spp. decreased, while Chaetoceros spp. and Leptocylindrus spp. increased. Total abundances of all three genera increased in the lower salinity treatments. These findings could portend changes in the phytoplankton community composition in the Gulf of Alaska as the climate warms and river discharge increases in the coming decades. Furthermore, the findings support previous assertions that submarine groundwater discharge, with higher salinity than river water, is a preferable source of nutrients to the genus Pseudo-nitzschia.

  3. The Pacific coastal waters off Washington are in- fluenced by an ...

    African Journals Online (AJOL)

    spamer

    In Harmful Algae. Reguera, B., Blanco, J., Fernández, M. L. and T. Wyatt. (Eds). Paris; Xunta de Galicia and Intergovernmental. Oceanographic Commission of UNESCO: 274–277. SAYCE, K. and R. A. HORNER 1996 — Pseudo-nitzschia spp. in. Willapa Bay, Washington, 1992 and 1993. In Harmful and. Toxic Algal Blooms.

  4. Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific.

    Science.gov (United States)

    Silver, Mary W; Bargu, Sibel; Coale, Susan L; Benitez-Nelson, Claudia R; Garcia, Ana C; Roberts, Kathryn J; Sekula-Wood, Emily; Bruland, Kenneth W; Coale, Kenneth H

    2010-11-30

    Near-surface waters ranging from the Pacific subarctic (58°N) to the Southern Ocean (66°S) contain the neurotoxin domoic acid (DA), associated with the diatom Pseudo-nitzschia. Of the 35 stations sampled, including ones from historic iron fertilization experiments (SOFeX, IronEx II), we found Pseudo-nitzschia at 34 stations and DA measurable at 14 of the 26 stations analyzed for DA. Toxin ranged from 0.3 fg·cell(-1) to 2 pg·cell(-1), comparable with levels found in similar-sized cells from coastal waters. In the western subarctic, descent of intact Pseudo-nitzschia likely delivered significant amounts of toxin (up to 4 μg of DA·m(-2)·d(-1)) to underlying mesopelagic waters (150-500 m). By reexamining phytoplankton samples from SOFeX and IronEx II, we found substantial amounts of DA associated with Pseudo-nitzschia. Indeed, at SOFeX in the Antarctic Pacific, DA reached 220 ng·L(-1), levels at which animal mortalities have occurred on continental shelves. Iron ocean fertilization also occurs naturally and may have promoted blooms of these ubiquitous algae over previous glacial cycles during deposition of iron-rich aerosols. Thus, the neurotoxin DA occurs both in coastal and oceanic waters, and its concentration, associated with changes in Pseudo-nitzschia abundance, likely varies naturally with climate cycles, as well as with artificial iron fertilization. Given that iron fertilization in iron-depleted regions of the sea has been proposed to enhance phytoplankton growth and, thereby, both reduce atmospheric CO(2) and moderate ocean acidification in surface waters, consideration of the potentially serious ecosystem impacts associated with DA is prudent.

  5. Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific

    Science.gov (United States)

    Silver, Mary W.; Bargu, Sibel; Coale, Susan L.; Benitez-Nelson, Claudia R.; Garcia, Ana C.; Roberts, Kathryn J.; Sekula-Wood, Emily; Bruland, Kenneth W.; Coale, Kenneth H.

    2010-01-01

    Near-surface waters ranging from the Pacific subarctic (58°N) to the Southern Ocean (66°S) contain the neurotoxin domoic acid (DA), associated with the diatom Pseudo-nitzschia. Of the 35 stations sampled, including ones from historic iron fertilization experiments (SOFeX, IronEx II), we found Pseudo-nitzschia at 34 stations and DA measurable at 14 of the 26 stations analyzed for DA. Toxin ranged from 0.3 fg·cell−1 to 2 pg·cell−1, comparable with levels found in similar-sized cells from coastal waters. In the western subarctic, descent of intact Pseudo-nitzschia likely delivered significant amounts of toxin (up to 4 μg of DA·m−2·d−1) to underlying mesopelagic waters (150–500 m). By reexamining phytoplankton samples from SOFeX and IronEx II, we found substantial amounts of DA associated with Pseudo-nitzschia. Indeed, at SOFeX in the Antarctic Pacific, DA reached 220 ng·L−1, levels at which animal mortalities have occurred on continental shelves. Iron ocean fertilization also occurs naturally and may have promoted blooms of these ubiquitous algae over previous glacial cycles during deposition of iron-rich aerosols. Thus, the neurotoxin DA occurs both in coastal and oceanic waters, and its concentration, associated with changes in Pseudo-nitzschia abundance, likely varies naturally with climate cycles, as well as with artificial iron fertilization. Given that iron fertilization in iron-depleted regions of the sea has been proposed to enhance phytoplankton growth and, thereby, both reduce atmospheric CO2 and moderate ocean acidification in surface waters, consideration of the potentially serious ecosystem impacts associated with DA is prudent. PMID:21068374

  6. Re-examination of a Sphaerotermia and a Gaillonella (Bacillariophyceae) from the Ehrenberg Collection, Berlin (Germany)

    Czech Academy of Sciences Publication Activity Database

    Houk, Václav

    2010-01-01

    Roč. 25, č. 2 (2010), s. 293-306 ISSN 0269-249X Institutional research plan: CEZ:AV0Z60050516 Keywords : centric diatom s * valve morphology * taxonomy Subject RIV: EF - Botanics Impact factor: 1.030, year: 2010

  7. Monitoring rapid valve formation in the pennate diatom Navicula salinarum (Bacillariophyceae)

    NARCIS (Netherlands)

    Hazelaar, S; van der Strate, HJ; Gieskes, WWC; Vrieling, EG

    After each division of a diatom cell, a new siliceous hypovalve is formed inside the silica deposition vesicle (SDV). We present the sequence of this early formation of the new valve in the pennate marine diatom Navicula salinarum (Grunow) Hustedt, visualized by using the fluorescent probe

  8. Asterionellopsis tropicalis (Bacillariophyceae): a new tropical species found in diatom accumulations.

    Science.gov (United States)

    Franco, Andréa de Oliveira da Rocha; They, Ng Haig; Canani, Luis Gustavo de Castro; Maggioni, Rodrigo; Odebrecht, Clarisse

    2016-10-01

    The diatom Asterionellopsis glacialis sensu lato forms high-density patches in the surf zone of some sandy beaches worldwide and was until recently considered a cosmopolitan species. With the recent description of four cryptic species, the identity of specimens found in these accumulations remains uncertain. In this study, diatom patches were sampled from two sandy beaches of the Brazilian coast: one tropical (Futuro Beach, 3° S; 38° W) and one subtropical (Cassino Beach, 32° S; 52° W). Fine structure of frustules and the sequencing of three phylogenetic markers revealed the subtropical strains to be A. guyunusae and the tropical strains to be a new species, here described as Asterionellopsis tropicalis sp. nov. A. tropicalis was differentiated morphologically by the number of striae in 10 μm at the foot pole and head (39-44; 38-45, respectively), from A. lenisilicea (46-55; 46-64), A. maritima (46-51; 46-60), and A. thurstonii (42-58; 55-70). The number of striae at the head region of the valvocopula (10 μm) helped to distinguish A. tropicalis (56-62) from A. guyunusae (61-64), but A. tropicalis was morphologically undistinguishable from A. glacialis. The sequence divergence from other identified Asterionellopsis species was 13%-16% (Cox1), 11%-12% (5.8S + ITS2) and 2%-6% (RbcL), and A. tropicalis formed a distinct monophyletic clade with high support in all analyzed phylogenetic trees (single or multi-locus). This work will aid in the understanding of the ecological and physiological diversity of diatom patches that are key to the trophic webs of sandy beaches. © 2016 Phycological Society of America.

  9. Ocorrência de Auricula complexa (Bacillariophyceae na plataforma continental de Pernambuco

    Directory of Open Access Journals (Sweden)

    Núbia Abrantes Gomes

    1989-01-01

    Full Text Available Aurícula complexa (Gregory Cleve (Auriculaceae, Bacülariophyceae é assinalada pela primeira vez para as águas costeiras de Pernambuco, NE do Brasil. A espécie foi encontrada em amostras de plancton, coletadas durante o período de março/87 a fevereiro/88, em quatro estações, localizadas em um perfil perpendicular à costa. O trabalho fornece descrição, distribuição na área estudada e dados ecológicos da espécie, que esteve presente em nove das 48 amostras coletadas. Quantitativamente foi pouco representativa, com percentuais que não atingiram mais que 0,5% da população fitoplanctônica total.Auricula complexa (Gregory Cleve (Auriculaceae, Bacülariophyceae is mentioned for the first time to coastal waters of Pernambuco, Northeastern Brazil. The species was found in plankton samples collected from March/1987 to February/1988 in four stations located in a line perpendicular to the coast. Description, distribution in the area studied, and ecological data are givem. Auricula complexa (Gregory Cleve was observed in 9 out of the 48 samples examined, with percentages not higher than 0,5% of the total phytoplancton population.

  10. New records of amphoroid diatoms (Bacillariophyceae from Cachoeira River, Northeast Brazil

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    KP Cavalcante

    Full Text Available Amphoroid taxa have been revised in recent decades. Many species formerly assigned to Amphora have been transferred to other recently proposed genera, as Seminavis (Naviculaceae and Halamphora (Catenulaceae. In Brazil, there are few studies focused on amphoroid taxonomy. This study presents a taxonomic investigation of five uncommon amphoroid taxa from Brazilian diatom flora: Seminavis pusilla, S. strigosa, Amphora ectorii, Halamphora ghanensis and Halamphora sp. Seminavis strigosa is identical in valve morphology and morphometrical data to Amphora twenteana, and its synonymy is proposed. Seminavis pusilla, poorly found in Brazilian waters, has expanded its distribution. Halamphora ghanensis is a new record to American continent while Amphora ectorii are new to Brazilian aquatic systems. Halamphora sp. has distinct ultrastructural features in relation to similar species and is probably new for science.

  11. Oxidative stress responses in the marine antarctic diatom Chaetoceros brevis (Bacillariophyceae) during photoacclimation

    NARCIS (Netherlands)

    Janknegt, P.J.; van de Poll, W.H.; Visser, R.J.W.; Rijstenbil, J.W.; Buma, A.G.J.

    2008-01-01

    The enzyme superoxide dismutase (SOD) holds a key position in the microalgal antioxidant network. The present research focused on oxidative stress responses in the Antarctic diatom Chaetoceros brevis F. Schütt during transition to excess (including ultraviolet radiation [UVR]) and limiting

  12. Daily fluctuations of exopolymers in cultures of the benthic diatoms Cylindrotheca closterium and Nitzschia sp (Bacillariophyceae)

    NARCIS (Netherlands)

    de Brouwer, J.F.C.; Stal, L.J.

    2002-01-01

    Dynamics in the production of extracellular polymeric substances (EPS) were investigated for the benthic diatoms Cylindrotheca closterium (Ehrenberg) and Nitzschia sp. The effect of growth phase and light:dark conditions were examined using axenic cultures. Two EPS fractions were distinguished.

  13. RESPUESTA DE Navicula rhynchocephala (BACILLARIOPHYCEAE AL INCREMENTO DE NUTRIENTES EN UN ARROYO ANDINO (COLOMBIA.

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    SILVIA JULIANA MORALES-DUARTE

    2010-01-01

    Full Text Available Para evaluar el efecto de la adición de amonio (NH4+ y fosfatos (PO43- sobre la estructura de la comunidad de diatomeas en el sector medio del río Tota (Boyacá, Colombia, se cuantificó la densidad de 98 especies de diatomeas mediante la utilización de sustratos artificiales en dos tramos con condiciones ambientales similares (control e impacto del sector medio del río Tota. Se incrementaron las concentraciones de amonio y fosfato en el tramo experimental a dos veces las del tramo control mediante la fertilización controlada. Navicula rhynchocephala disminuyó significativamente sus densidades en el tramo experimental, por lo que puede ser considerada como una especie que responde al incremento de nutrientes.

  14. Genotype-by-temperature interactions may help to maintain clonal diversity in Asterionella formosa (Bacillariophyceae)

    NARCIS (Netherlands)

    Gsell, A.S.; De Senerpont Domis, L.N.; Przytulska-Bartosiewicz, A.; Mooij, W.M.; Van Donk, E.; Ibelings, B.W.

    2012-01-01

    Marine and freshwater phytoplankton populations often show large clonal diversity, which is in disagreement with clonal selection of the most vigorous genotype(s). Temporal fluctuation in selection pressures in variable environments is a leading explanation for maintenance of such genetic diversity.

  15. Genotype-by-temperature interactions may help to maintain clonal diversity in asterionella formosa (Bacillariophyceae)

    NARCIS (Netherlands)

    Gsell, A.S.; Domis, L.N.D.; Przytulska-Bartosiewicz, A.; Mooij, W.M.; Donk, van E.; Ibelings, B.W.

    2012-01-01

    Marine and freshwater phytoplankton populations often show large clonal diversity, which is in disagreement with clonal selection of the most vigorous genotype(s). Temporal fluctuation in selection pressures in variable environments is a leading explanation for maintenance of such genetic diversity.

  16. Diatoms (Bacillariophyceae from the Valley of the Great Lakes in Western Mongolia

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    Mark B. Edlund

    2010-06-01

    Full Text Available T he Valley of the Great Lakes (VOGL in western Mongolia is dominated by two main (Uvs, Khyargas and many minor closed basin lake systems. In 2004 and 2005, we sampled diatom communities from the surfi cial sediment of 64 lakes in the western Mongolian provinces of Uvs, Khovd, Zavkhan, and Bayan-Ulgii. Lakes ranged in water chemistry from fresh to hypersaline, oligotrophic to hypertrophic, and from low elevation VOGL lakes to high elevation lakes in the Altai Mountains. Over 300 diatom species were identifi ed in the sediment samples including a diverse fl ora limited to saline lakes, many widespread taxa, many new reports for the Mongolian diatom fl ora, and several new and possibly endemic species. We also review recent diatom literature from Mongolia including fl oristic surveys, paleo-ecology, and water quality studies.

  17. Ecological differentiation between sympatric pseudocryptic species in the estuarine benthic diatom Navicula phyllepta (Bacillariophyceae)

    NARCIS (Netherlands)

    Vanelslander, B.; Creach, V.; Vanormelingen, P.; Ernst, A.; Chepurnov, V.A.; Sahan, E.; Muyzer, G.; Stal, L.J.; Vyverman, W.; Sabbe, K.

    2009-01-01

    The occurrence of cryptic and pseudocryptic species, often living in sympatry, is widespread among microalgae. This phenomenon raises important questions about niche partitioning between these closely related species. To date, however, few studies have addressed the ecological mechanisms underlying

  18. ECOLOGICAL DIFFERENTIATION BETWEEN SYMPATRIC PSEUDOCRYPTIC SPECIES IN THE ESTUARINE BENTHIC DIATOM NAVICULA PHYLLEPTA (BACILLARIOPHYCEAE)(1).

    Science.gov (United States)

    Vanelslander, Bart; Créach, Véronique; Vanormelingen, Pieter; Ernst, Anneliese; Chepurnov, Victor A; Sahan, Emel; Muyzer, Gerard; Stal, Lucas J; Vyverman, Wim; Sabbe, Koen

    2009-12-01

    The occurrence of cryptic and pseudocryptic species, often living in sympatry, is widespread among microalgae. This phenomenon raises important questions about niche partitioning between these closely related species. To date, however, few studies have addressed the ecological mechanisms underlying sympatry in cryptic and pseudocryptic species. As a result, we have only a limited understanding of the factors that govern their distribution along environmental gradients. Here, we used the ribosomal internal transcribed spacer (ITS), 18S rRNA gene, and the RUBISCO LSU (rbcL) chloroplast gene sequence data together with cell wall morphology to show that estuarine populations of the widespread and common benthic diatom Navicula phyllepta Kütz. consist of pseudocryptic species. Growth rate measurements in function of salinity showed that N. phyllepta strains assigned to the different species differed in their tolerance to low salinities (<5 practical salinity units, psu), which was reflected by their different (but widely overlapping) distribution in the Westerschelde estuary (the Netherlands). Multiple regression analyses of the factors determining the abundance of the different species in field samples revealed that, in addition to salinity, sediment type and ammonium concentrations were probably equally important. Our results show that N. phyllepta sensu lato comprises different species with specialized ecophysiological characteristics rather than generalists with a broad adaptability to different environmental conditions. © 2009 Phycological Society of America.

  19. Diatomeas (Bacillariophyceae del marjal Oliva-Pego (Comunidad Valenciana, España

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    Aboal Sanjurjo, Marina

    2008-06-01

    Full Text Available As the result of a study of algal communities of Marjal Oliva- Pego, we present the diatoms collected at 4 different locations: the Bullent river, Ullal, close to the Bullent river, Bassa Sineu and Font Salat. Fifty one species of diatoms were identified, belonging to 28 genera, with 5 varieties and 1 form. Thirty five species (66 % are reported as cosmopolite and 5 (9 % with tropical inclination. Twenty five species came from brackish water and 7 from fresh water. Descriptions for each species and both taxonomic and ecological notes are presented. Two new species are reported for Spanish flora: Kolbesia amoena (Hustedt Kingstom and Navicula subadnata Hustedt.Como resultado de un estudio de las comunidades algales del marjal Oliva-Pego se ofrece el resultado de cuatro recolecciones realizadas en cuatro puntos diferentes: río Bullent, Ullal cercano al río Bullent, Bassa Sineu y la Font Salat. Se identificaron 51 táxones de diatomeas, que corresponden a 28 géneros, con cinco variedades y una forma, de los cuales 25 son especies propias de aguas salobres o ligeramente salobres y siete de aguas dulces. Treinta y cinco especies (66 % son cosmopolitas y cinco (9 % tienen afinidades tropicales. Se ofrecen descripciones para cada una de ellas con notas taxonómicas y ecológicas, y se citan dos nuevas especies para España: Kolbesia amoena (Hustedt Kingstom y Navicula subadnata Hustedt.

  20. Using quantitative PCR to determine the distribution of a semicryptic benthic diatom, Navicula phyllepta (Bacillariophyceae)

    NARCIS (Netherlands)

    Creach, V.; Ernst, A.; Sabbe, K.; Stal, L.J.; Vanelslander, B.; Vyverman, W.

    2006-01-01

    Evidence has accumulated during the last decade showing that many established diatom morpho-species actually consist of several semicryptic or truly cryptic species. As these species are difficult or even impossible to differentiate by microscopic analysis, there is virtually no information on how

  1. Rachael Carson Lecture - Algal Toxins in the Deep Blue Sea: an Environmental Concern?

    Science.gov (United States)

    Silver, M. W.; Bargu, S.

    2008-05-01

    Many land plants are known to possess toxins, presumably for grazer deterrence, whereas toxins in marine phytoplankton are a much rarer phenomenon, particularly in open ocean (blue water) environments. Several dozen phytoplankton species, frequently dinoflagellates but also some diatoms, form "harmful algal blooms" nearshore: here their toxins can contaminate filter-feeding shellfish resulting in poisoning "syndromes" when humans consume the tainted shellfish. The present rise in such coastal events is a likely consequence of human activities. In blue water, open ocean environments, the filamentous cyanobacterium Trichodesmium (a blue green alga) is one of the few bloom-forming toxin producers and hosts a consortium of microorganisms that may be partially immune to its toxins. Pseudo-nitzschia, a ubiquitous genus of diatoms recently has been shown to include coastal species that produce domoic acid (DA), a neurotoxin that passes through the food web, sometimes with resulting deaths of marine birds and mammals. Oceanic species of Pseudo-nitzschia also exist but are less well known, and DA has not yet been found in them. Here we review some general features of toxic marine phytoplankton, recent studies on DA in coastal ecosystems and describe some of our findings on blue water Pseudo-nitzschia. We will summarize laboratory experiments that show complex patterns of DA retention and release into the water when Fe is added to coastal Pseudo-nitzschia cultures. In oceanic species, equivalent experiments on cell physiology are limited and the natural species and abundance patterns poorly known. Here we present our recent discovery that DA occurs in oceanic Pseudo-nitzschia and review evidence from the literature that this genus may be preferentially enhanced when iron is added to HNLC (high nutrient, low chlorophyll) waters: areas where nitrogen and phosphorus are not yet depleted, but iron concentrations and phytoplankton biomass are low. The rapid growth of these DA

  2. Subsurface seeding of surface harmful algal blooms observed through the integration of autonomous gliders, moored environmental sample processors, and satellite remote sensing in southern California

    KAUST Repository

    Seegers, Bridget N.

    2015-04-01

    An observational study was performed in the central Southern California Bight in Spring 2010 to understand the relationship between seasonal spring phytoplankton blooms and coastal processes that included nutrient input from upwelling, wastewater effluent plumes, and other processes. Multi-month Webb Slocum glider deployments combined with MBARI environmental sample processors (ESPs), weekly pier sampling, and ocean color data provided a multidimensional characterization of the development and evolution of harmful algal blooms (HABs). Results from the glider and ESP observations demonstrated that blooms of toxic Pseudo-nitzschia sp. can develop offshore and subsurface prior to their manifestation in the surface layer and/or near the coast. A significant outbreak and surface manifestation of the blooms coincided with periods of upwelling, or other processes that caused shallowing of the pycnocline and subsurface chlorophyll maximum. Our results indicate that subsurface populations can be an important source for “seeding” surface Pseudo-nitzschia HAB events in southern California.

  3. An unprecedented coastwide toxic algal bloom linked to anomalous ocean conditions.

    Science.gov (United States)

    McCabe, Ryan M; Hickey, Barbara M; Kudela, Raphael M; Lefebvre, Kathi A; Adams, Nicolaus G; Bill, Brian D; Gulland, Frances M D; Thomson, Richard E; Cochlan, William P; Trainer, Vera L

    2016-10-16

    A coastwide bloom of the toxigenic diatom Pseudo-nitzschia in spring 2015 resulted in the largest recorded outbreak of the neurotoxin, domoic acid, along the North American west coast. Elevated toxins were measured in numerous stranded marine mammals and resulted in geographically extensive and prolonged closures of razor clam, rock crab, and Dungeness crab fisheries. We demonstrate that this outbreak was initiated by anomalously warm ocean conditions. Pseudo-nitzschia australis thrived north of its typical range in the warm, nutrient-poor water that spanned the northeast Pacific in early 2015. The seasonal transition to upwelling provided the nutrients necessary for a large-scale bloom; a series of spring storms delivered the bloom to the coast. Laboratory and field experiments confirming maximum growth rates with elevated temperatures and enhanced toxin production with nutrient enrichment, together with a retrospective analysis of toxic events, demonstrate the potential for similarly devastating ecological and economic disruptions in the future.

  4. Seasonal and annual dynamics of harmful algae and algal toxins revealed through weekly monitoring at two coastal ocean sites off southern California, USA

    KAUST Repository

    Seubert, Erica L.

    2013-01-04

    Reports of toxic harmful algal blooms (HABs) attributed to the diatom Pseudo-nitzschia spp. have been increasing in California during the last several decades. Whether this increase can be attributed to enhanced awareness and monitoring or to a dramatic upswing in the development of HAB events remains unresolved. Given these uncertainties, the ability to accurately and rapidly identify an emerging HAB event is of high importance. Monitoring of HAB species and other pertinent chemical/physical parameters at two piers in southern California, Newport and Redondo Beach, was used to investigate the development of a site-specific bloom definition for identifying emerging domoic acid (DA) events. Emphasis was given to abundances of the Pseudo-nitzschia seriata size category of Pseudo-nitzschia due to the prevalence of this size class in the region. P. seriata bloom thresholds were established for each location based on deviations from their respective long-term mean abundances, allowing the identification of major and minor blooms. Sixty-five percent of blooms identified at Newport Beach coincided with measurable DA concentrations, while 36 % of blooms at Redondo Beach coincided with measurable DA. Bloom definitions allowed for increased specificity in multiple regression analysis of environmental forcing factors significant to the presence of DA and P. seriata. The strongest relationship identified was between P. seriata abundances 2 weeks following upwelling events at Newport Beach. © 2012 Springer-Verlag Berlin Heidelberg.

  5. Seasonal and annual dynamics of harmful algae and algal toxins revealed through weekly monitoring at two coastal ocean sites off southern California, USA.

    Science.gov (United States)

    Seubert, Erica L; Gellene, Alyssa G; Howard, Meredith D A; Connell, Paige; Ragan, Matthew; Jones, Burton H; Runyan, Jennifer; Caron, David A

    2013-10-01

    Reports of toxic harmful algal blooms (HABs) attributed to the diatom Pseudo-nitzschia spp. have been increasing in California during the last several decades. Whether this increase can be attributed to enhanced awareness and monitoring or to a dramatic upswing in the development of HAB events remains unresolved. Given these uncertainties, the ability to accurately and rapidly identify an emerging HAB event is of high importance. Monitoring of HAB species and other pertinent chemical/physical parameters at two piers in southern California, Newport and Redondo Beach, was used to investigate the development of a site-specific bloom definition for identifying emerging domoic acid (DA) events. Emphasis was given to abundances of the Pseudo-nitzschia seriata size category of Pseudo-nitzschia due to the prevalence of this size class in the region. P. seriata bloom thresholds were established for each location based on deviations from their respective long-term mean abundances, allowing the identification of major and minor blooms. Sixty-five percent of blooms identified at Newport Beach coincided with measurable DA concentrations, while 36 % of blooms at Redondo Beach coincided with measurable DA. Bloom definitions allowed for increased specificity in multiple regression analysis of environmental forcing factors significant to the presence of DA and P. seriata. The strongest relationship identified was between P. seriata abundances 2 weeks following upwelling events at Newport Beach.

  6. Eunotiaceae (Bacillariophyceae em igarapés da Amazônia Central, Manaus e Presidente Figueiredo, Brasil Eunotiaceae (Bacillariophyceae from central Amazon rivers, Manaus and Presidente Figueiredo districts, Brasil

    Directory of Open Access Journals (Sweden)

    Fernanda Ferrari

    2007-01-01

    Full Text Available Estudos florísticos e taxonômicos envolvendo diatomáceas são escassos para a região amazônica. As publicações existentes incluem registros de diatomáceas da Amazônia brasileira, do Equador, da Colômbia e do Peru e comumente mostram que Eunotia e Actinella (Eunotiaceae são gêneros bem representados nessa região. A maioria dos igarapés amazônicos costuma apresentar potencial hidrogeniônico (pH ácido, característica aquática que promove o desenvolvimento de uma comunidade típica de diatomáceas, dominada por espécimes de Eunotiaceae. O objetivo deste trabalho foi providenciar um levantamento florístico das espécies de Eunotiaceae presentes em igarapés da Amazônia Central brasileira e registrar os morfotipos de algumas espécies. Amostras fitoplanctônicas e perifíticas foram coletadas em cinco igarapés na rodovia BR-174, em Manaus e Presidente Figueiredo, em setembro e outubro de 1996 e fevereiro e março de 1997. Lâminas permanentes foram preparadas de acordo com a técnica de oxidação lenta para o estudo qualitativo. Vinte e três espécies pertencentes ao gênero Eunotia e seis ao gênero Actinella foram determinadas. Chaves dicotômicas de identificação, descrição detalhada, comentários relevantes e ilustrações foram providenciadas para cada táxon determinado. Morfotipos foram documentados para Eunotia zygodon. Espécies raramente citadas na literatura foram registradas, tais como, Eunotia falcifera e Eunotia rostellata.Floristic and taxonomical studies about diatoms to Amazonian region are commonly well represented by Eunotia and Actinella (Eunotiaceae. The available works include diatom assemblage from Brazilian, Ecuadorian, Colombian and Peruvian Amazonia. The local streams often present acid pH which provides environmental conditions to develop a very particular diatom community dominated by specimens of Eunotiaceae. Thus, the aim of this paper is to give a floristic survey of Eunotiaceae from central Amazonian rivers and to register the typical morphologic frustule variations of some species. Planktonic and periphytic samples were collected from five rivers located at the BR-174 highway, near Manaus and Presidente Figueiredo districts, during 1996 and 1997. Slides were prepared in accordance with the technique of slow oxidation for the qualitative determination. Twenty-three species of Eunotia and six of Actinella were identified. Dicotomic keys, taxonomic comments and photographic illustrations were added. Morphotypes of Eunotia zygodon were registered. Species scarcelly mentioned on diatom literature were registered, such as, Eunotia falcifera and Eunotia rostellata.

  7. Evaluación de la calidad del agua fluvial con diatomeas (Bacillariophyceae, una experiencia en Tacna, Perú Evaluation of the quality of river water with diatoms (Bacillariophyceae: an experience in Tacna, Peru

    Directory of Open Access Journals (Sweden)

    José Calizaya-Anco

    2013-03-01

    Full Text Available Con el objetivo de evaluar la calidad del agua de la cuenca del río Locumba, Tacna (Perú, se tomaron muestras de agua de diez estaciones ubicadas a lo largo de la cuenca del río Locumba, durante seis periodos en un ciclo anual. Asimismo, se evaluó la diversidad y número de diatomeas y once parámetros fisicoquímicos para determinar el grado de contaminación del agua. Encontramos que conforme se desciende en la cuenca, la diversidad de diatomeas disminuyó de 2,37 bits cel-1 a 0,71 bits cel-1 y el gradiente de contaminantes se incrementó. Además, con este incremento, se observó un aumento en el número de especies tolerantes a altos niveles de perturbación ambiental. Se observó un incremento en todos los parámetros fisicoquímicos empleados para evaluar el grado de contaminación. Se sugiere que las diatomeas pueden ser adecuados bioindicadores al momento de evaluar la calidad de agua en esta cuencaIn order to evaluate the quality of the water of the Locumba river, Tacna (Peru, water samples were taken from ten stations located along the Locumba river basin, during six periods in an annual cycle. The diversity and number of diatoms was also evaluated, together with eleven physiochemical parameters in order to determine the degree of water contamination. We found that as the basin advanced down the mountain, the diversity of diatoms decreased from 2.37 bits cell-1 to 0.71 bits cell-1 and the gradient of contaminants increased. In addition to this increase, the number of species tolerant to high levels of environmental disturbance rose. An increase in all physiochemical parameters used to evaluate the degree of contamination was observed. These results suggest that diatoms can be adequate bioindicators when evaluating the quality of water in this basin

  8. Diatomeas (Bacillariophyceae de Ambientes Acuáticos de Altura de la Provincia de Catamarca, Argentina II Diatoms (Bacillariophyceae from high altitude aquatic environments of Catamarca Province in Argentina. II

    Directory of Open Access Journals (Sweden)

    Nora I. Maidana

    2006-07-01

    Full Text Available En esta contribución al conocimiento de las diatomeas de humedales de altura, se analizaron 14 muestras pertenecientes a distintos cuerpos de agua de la Provincia de Catamarca (Argentina, entre los 2420 y 4240 m s. n. m. Se identificaron 208 taxones infragenéricos de los cuales 90 son nuevas citas para la Provincia de Catamarca. Se mencionan por primera vez para Argentina los géneros: Frankophila y Microcostatus y las especies: Achnanthes thermalis var. rumrichorum Lange-Bertalot; Amphora mira Krasske; Brachysira atacamae Hustedt; Frankophila similioides Lange-Bertalot & Rumrich; Gomphonema punae Lange-Bertalot & Rumrich; Haloroundia speciosa Diaz & Maidana; Luticola mollis Lange-Bertalot& Rumrich; Mastogloia atacamae Hustedt; Microcostatus andinus Lange-Bertalot & Rumrich; Navicula atacamana Patrick; Navicula parinacota Rumrich & Lange-Bertalot; Planothidium chilense (Hustedt Lange-Bertalot; Staurosira pseudoconstruens (Marciniak Lange-Bertalot; Surirella chilensis var constricta Hustedt y Surirella wetzellii Hustedt. Además se propone una nueva combinación: Ulnaria ulna var. constricta.In this research focusing the diatoms of high topographic wetlands, 14 samples of different freshwater bodies (between 2,420 and 4,240 m a. s. l. were studied. Two hundred and eight infrageneric taxa were identified, 90 of them are new records for the Catamarca province. The genera: Frankophila and Microcostatus and the species Achnanthes thermalis var. rumrichorum Lange-Bertalot; Amphora mira Krasske; Brachysira atacamae Hustedt; Frankophila similioides Lange-Bertalot & Rumrich; Gomphonema punae Lange-Bertalot & Rumrich; Haloroundia speciosa Diaz & Maidana; Luticola mollis Lange-Bertalot & Rumrich; Mastogloia atacamae Hustedt; Microcostatus andinus Lange-Bertalot& Rumrich; Navicula atacamana Patrick; Navicula parinacota Rumrich & Lange-Bertalot; Planothidium chilense (Hustedt Lange-Bertalot; Staurosira pseudoconstruens (Marciniak Lange-Bertalot; Surirella chilensis var constricta Hustedt y Surirella wetzellii Hustedt are new records for Argentina. A new combination is proposed: Ulnaria ulna var. constricta.

  9. Late quaternary Nupela taxa of Retezat Mts (S. Carpathians, with description of Nupela pocsii sp. nov. (Bacillariophyceae

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    Buczkó Krisztina

    2013-12-01

    Full Text Available Nupela pocsii Buczkó & Wojtal, sp. nov., a new species from the Retezat Mountains (S. Carpathians, is described. High asymmetry (along apical and transapical axes and in raphe pattern and small dimensions are the most characteristic features of this taxon. Nupela pocsii was found during paleolimnological research in early Holocene sediment of Lake Brazi. Seven other representatives of the genus Nupela were detected in high-resolution diatom analyses of three lake sediment sequences of the Retezat Mts: Nupela fennica (Hustedt Lange-Bertalot, N. imperfecta (Schimanski Lange-Bertalot, N. impexiformis (Lange-Bertalot Lange-Bertalot, N. lapidosa (Krasske Lange-Bertalot, N. paludigena (R. P. Scherer Lange-Bertalot, N. vitiosa (Schimanski Siver & Hamilton and an unidentified Nupela Vyverman & Compere species. Our results suggest high diversity of oligotraphenic species in these mountain lakes during their ontogeny, which began 17,000-15,000 years ago. In addition to the newly described species this is also the first record of N. paludigena in European lakes, although its occurrence was previously documented by SEM and LM from Lake Saint Anna without correct identification.

  10. Genetic variation in Asterionella formosa (Bacillariophyceae) is it linked to frequent epidemics of host-specific parasitic fungi?

    NARCIS (Netherlands)

    De Bruin, A.; Ibelings, B.W.; Rijkeboer, M.; Brehm, Michaela; Van Donk, E.

    2004-01-01

    Understanding of the genetic basis for susceptibility and resistance is still lacking for most aquatic host-parasite systems, for instance, for phytoplankton and their fungal parasites. Fungal parasites can have significant effects on phytoplankton populations, mainly through their ability to

  11. ENVIRONMENTAL CONTROL OF STALK LENGTH IN THE BLOOM-FORMING, FRESHWATER BENTHIC DIATOM DIDYMOSPHENIA GEMINATA (BACILLARIOPHYCEAE)(1).

    Science.gov (United States)

    Kilroy, Cathy; Bothwell, Max

    2011-10-01

    Blooms of the freshwater stalked diatom Didymosphenia geminata (Lyngb.) M. Schmidt in A. Schmidt typically occur in oligotrophic, unshaded streams and rivers. Observations that proliferations comprise primarily stalk material composed of extracellular polymeric substances (EPS) led us to ask whether or not the production of excessive EPS is favored under nutrient-limited, high-light conditions. We conducted experiments in outdoor flumes colonized by D. geminata using water from the oligotrophic, D. geminata-affected Waitaki River, South Island, New Zealand, to determine the relationship between D. geminata stalk length, cell division rates, and light intensity under ambient and nutrient-enriched conditions. Stalk lengths were measured in situ, and cell division rates were estimated as the frequency of dividing cells (FDC). FDC responded positively to increasing light intensity and to nutrient additions (N+P and P). Under ambient conditions, stalk length increased as light level increased except at low ambient light levels and temperature. Nutrient enrichment resulted in decreased stalk length and negative correlations with FDC, with this effect most evident under high light. Our results are consistent with the hypothesis that extensive stalk production in D. geminata occurs when cell division rates are nutrient limited and light levels are high. Thus, photosynthetically driven EPS production in the form of stalks, under nutrient-limited conditions, may explain the development of very high biomass in this species in oligotrophic rivers. The responses of FDC and stalk length under nutrient-replete conditions are also consistent with occurrences of D. geminata as a nondominant component of mixed periphyton communities in high-nutrient streams. © 2011 Phycological Society of America.

  12. Taxonomy, morphology and distribution of Cymatosiraceae (Bacillariophyceae) in the littorals of Santa Catarina and Rio Grande do Sul

    OpenAIRE

    Garcia, Marinês

    2016-01-01

    Species of Cymatosiraceae (diatoms) studied from Santa Catarina and Rio Grande do Sul littorals: Campylosira cymbelliformis, Cymatosira belgica, Cymatosirella minutissima, Plagiogrammopsis minima and Plagiogrammopsis vanheurckii) are presented with a morphological description, dimension data, distribution in the studied area and are illustrated in light microscope, and scanning and transmission electron microscopes. Superficial sand samples from the swash zone and plankton were collected from...

  13. Trigonium curvatus sp nov and Trigonium arcticum (Bacillariophyceae) from the surface sediments of Prydz Bay, east Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Abhilash, N.; Mohan, R.; Shetye, S.; Gazi, S.; Jafar, S.A

    Here we propose a new species of genus Trigonium namely Trigonium curvatus from the surface sediments of coastal Antarctica A comparative study was done between Trigonium curvatus and Trigonium arcticum to find out the differential morphological...

  14. Cryopreservation of economically valuable marine micro-algae in the classes Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dinophyceae, Haptophyceae, Prasinophyceae, and Rhodophyceae.

    Science.gov (United States)

    Rhodes, Lesley; Smith, John; Tervit, Robin; Roberts, Rodney; Adamson, Janet; Adams, Serean; Decker, Marie

    2006-02-01

    The ability to routinely cryopreserve micro-algal species reduces costs associated with maintaining large culture collections and reduces the risks of losing particular strains or species through contamination and genetic drift. Cryopreservation is also a useful adjunct in aquaculture hatcheries for strains of micro-algae where the nutritional status may change as a result of continuous sub-culture. In this study, cryopreservation of isolates from seven micro-algal classes was investigated. Successful candidates included the marine dinoflagellates Amphidinium carterae, Amphidinium trulla, and Gymnodinium simplex, and the haptophytes Chrysochromulina simplex, Prymnesium parvum, Prymnesium parvum f. patelliferum, Isochrysis galbana, and Pavlova lutheri. Also successfully cryopreserved were the planktonic diatoms Chaetoceros calcitrans, Chaetoceros muelleri, Chaetoceros sp., and the benthic Nitzschia ovalis, the chlorophyte Chlamydomonas coccoides, the rhodophyte Porphyridium purpureum, the prasinophytes Tetraselmis chuii, and Tetraselmis suecica, and the cyanophytes Raphidiopsis sp., and Aphanizomenon flos-aquae. All species were successfully cryopreserved using 15% Me2SO.

  15. Valve morphology and systematic position of Navicula walkeri (Bacillariophyceae), a diatom endemic to Oregon and California (USA)

    Science.gov (United States)

    Kociolek, J.P.; Spaulding, S.A.; Kingston, J.C.

    1998-01-01

    Variation in valve size and ultrastructure is documented for Navicula walkeri, a freshwater diatom species endemic to Oregon and central California (USA). In LM, this large diatom has longitudinal lines on either side of the axial area, as well as lineolate striae. External proximal raphe ends recurve toward the same side as the deflected distal ends. A large central nodule and bulbous areas at the terminus of each raphe branch are visible internally. The edges of an axial plate form the image of longitudinal lines. The suite of features present in N. walkeri suggests it is part of Navicula sensu stricto but occupies an isolated position within the group. Navicula sensu stricto is not an entirely homogeneous assemblage, and further refinements of the systematic affinities of its members may be warranted.

  16. CALCIUM RELEASE FROM INTRACELLULAR STORES IS NECESSARY FOR THE PHOTOPHOBIC RESPONSE IN THE BENTHIC DIATOM NAVICULA PERMINUTA (BACILLARIOPHYCEAE)(1).

    Science.gov (United States)

    McLachlan, Deirdre H; Underwood, Graham J C; Taylor, Alison R; Brownlee, Colin

    2012-06-01

    Complex photoreceptor pathways exist in algae to exploit light as a sensory stimulus. Previous studies have implicated calcium in blue-light signaling in plants and algae. A photophobic response to high-intensity blue light was characterized in the marine benthic diatom Navicula perminuta (Grunow) in van Heurck. Calcium modulators were used to determine the involvement of calcium in the signaling of this response, and the fluorescent calcium indicator Calcium Crimson was used to image changes in intracellular [Ca(2+) ] during a response. A localized, transient elevation of Calcium Crimson fluorescence was seen at the cell tip at the time of cell reversal. Intracellular calcium release inhibitors produced a significant decrease in the population photophobic response. Treatments known to decrease influx of extracellular calcium had no effect on the population photophobic response but did cause a significant decrease in average cell speed. As the increase in intracellular [Ca(2+) ] at the cell tip corresponded to the time of direction change rather than the onset of the light stimulus, it would appear that Ca(2+) constitutes a component of the switching mechanism that leads to reversal of the locomotion machinery. Our current evidence suggests that the source of this Ca(2+) is intracellular. © 2012 Phycological Society of America.

  17. Pseudocryptic diversity versus cosmopolitanism in diatoms: a case study on Navicula cryptocephala Kütz. (Bacillariophyceae) and morphologically similar taxa.

    Science.gov (United States)

    Poulícková, Aloisie; Veselá, Jana; Neustupa, Jirí; Skaloud, Pavel

    2010-07-01

    Despite the significance of diatoms in biomonitoring, many aspects of their biodiversity and geographical distribution are poorly understood. Recent evidence from molecular data has shown that traditional cosmopolitan and euryvalent morphospecies are often heterogeneous, containing cryptic or pseudo-cryptic species. It is important to establish whether these more finely differentiated species are also cosmopolitan or show restricted distributions. According to the standard freshwater diatom floras, Navicula cryptocephala and morphologically similar species (N. veneta, N. trivialis, N. gregaria and N. cryptotenella) are common, cosmopolitan freshwater pennate diatoms. Although allopatric and even sympatric populations of N. cryptocephala are extremely similar morphologically, they have previously been found to be highly polymorphic with respect to reproductive and nuclear characteristics; however, molecular data supporting the existence of cryptic diversity were lacking. Phylogenetic analyses (LSU rDNA, ITS of the rRNA operon) of 52 strains of N. cryptocephala-like diatoms confirmed the existence of genetically distinct lineages within N. cryptocephala, and revealed a close relationship between N. trivialis and N. cryptocephala. Cytological, reproductive and morphological variation, investigated by means of landmark-based geometric morphometrics, were in congruence with molecular data. Two pseudo-cryptic species within N. cryptocephala coexist sympatrically and are widely distributed, occurring in both European and Australian lakes. 2009 Elsevier GmbH. All rights reserved.

  18. LIGHT-INDUCED MOTILE RESPONSES OF THE ESTUARINE BENTHIC DIATOMS NAVICULA PERMINUTA AND CYLINDROTHECA CLOSTERIUM (BACILLARIOPHYCEAE)(1).

    Science.gov (United States)

    McLachlan, Deirdre H; Brownlee, Colin; Taylor, Alison R; Geider, Richard J; Underwood, Graham J C

    2009-06-01

    Motility of estuarine epipelic (mud-inhabiting) diatoms is an important adaptation to living in biofilms present within fine sediments. Motility allows cells to migrate within the photic zone in response to a wide range of environmental stimuli. The motile responses of two species of benthic diatoms to photon fluence rates and spectral quality were investigated. Cultures of Navicula perminuta (Grunow) in van Heurck and Cylindrotheca closterium (Ehrenb.) J. C. Lewin et Reimann both exhibited photoaccumulation at ∼200 μmol · m(-2)  · s(-1) and photodispersal from photon flux densities (PFDs) of ∼15 μmol · m(-2)  · s(-1) . Photokinesis (changing cell speed) contributed toward photodispersal for both species, and red light (λ = 681-691 nm) was most effective at inducing this process. N. perminuta showed a phototactic (directional) response, with active movement in response to a light gradient. Although this response was exhibited in white light, these directional responses were only elicited by wavelengths from 430 to 510 nm. In contrast, C. closterium did not exhibit phototaxis under any light conditions used in this study. Motile benthic diatoms thus exhibit complex and sophisticated responses to light quantity and quality, involving combinations of photokinesis and phototaxis, which can contribute toward explaining the patterns of large-scale cell movements observed in natural estuarine biofilms. © 2009 Phycological Society of America.

  19. Location and expression of frustulins in the pennate diatoms Cylindrotheca fusiformis, Navicula pelliculosa, and Navicula salinarum (Bacillariophyceae)

    NARCIS (Netherlands)

    van de Poll, WH; Vrieling, EG; Gieskes, WWC

    1999-01-01

    A detailed immunocytochemical and biochemical study of the location and expression of frustulins, a family of proteins associated with the frustules of diatoms, has been performed for Cylindrotheca fusiformis Reimann et Lewin, Navicula pelliculosa (Brebisson et Kutzing) Hilse, and Navicula salinarum

  20. Phosphate-limited growth of the marine diatom Thalassiosira weissflogii (Bacillariophyceae): evidence of non-monod growth kinetics(1).

    Science.gov (United States)

    Laws, Edward A; Pei, Shaofeng; Bienfang, Paul

    2013-04-01

    The marine diatom Thalassiosira weissflogii (Grunow) G. A. Fryxell & Hasle was grown in a chemostat over a series of phosphate-limited growth rates. Ambient substrate concentrations were determined from bioassays involving picomolar spikes of (33) P-labeled phosphate, and maximum uptake rates were determined from analogous bioassays that included the addition of micromolar concentrations of unlabeled phosphate and tracer concentrations of (33) P. The relationship between cell phosphorus quotas and growth rates was well described by the Droop equation. Maximum uptake rates of phosphate spikes were several orders of magnitude higher than steady state uptake rates. Despite the large size of the T. weissflogii cells, diffusion of phosphate through the boundary layer around the cells had little effect on growth kinetics, in part because the cellular N:P ratios exceeded the Redfield ratio at all growth rates. Fitting the Monod equation to the experimental data produced an estimate of the nutrient-saturated growth rate that was ~50% greater than the maximum growth rate observed in batch culture. A modified hyperbolic equation with a curvature that is a maximum in magnitude at positive growth rates gave a better fit to the data and an estimate of the maximum growth rate that was consistent with observations. The failure of the Monod equation to describe the data may reflect a transition from substrate to co-substrate limitation and/or the presence of an inducible uptake system. © 2013 Phycological Society of America.

  1. Microbial response to different phytoplankton-derived dissolved organic matter sources in the Ross Sea, Antarctica

    Science.gov (United States)

    Sipler, R. E.; Spackeen, J.; McQuaid, J.; Bertrand, E. M.; Roberts, Q. N.; Baer, S. E.; Hutchins, D. A.; Allen, A. E.; Bronk, D. A.

    2016-02-01

    Western Antarctic shelves are highly productive regions that play an important role in global carbon and nitrogen cycles, specifically serving as a critical sink for carbon dioxide. Fixed carbon is stored within the phytoplankton cell as particulate organic matter or released into the surrounding water as dissolved organic matter (DOM). These phytoplankton-derived sources of organic matter support higher trophic levels as well as heterotrophic bacterial growth and respiration. The composition of the phytoplankton-derived organic matter is a function of the taxa as well as the environmental conditions under which it is produced. Phytoplankton community composition within western Antarctic Seas changes throughout Austral spring and summer with early production dominated by ice algae, switching to pelagic diatoms and flagellates later in the season. The goal of this study was to compare the response of Ross Sea microbial communities to DOM produced by ice algae or late season diatoms, specifically recent isolates of Pseudo nitzschia obtained from the Ross Sea. During 5-day bioassay studies, exudates from a natural ice algal community and from Pseudo nitzschia sp. isolates were added to natural microbial communities collected from two different Ross Sea locations, an ice-edge and an ice-covered site. The bacterial response to the DOM additions was greatest in the ice-covered community with a 5 and 3-fold higher bacterial abundance in the ice algae DOM and Pseudo nitzschia DOM treatments, respectively, relative to the control. The ice edge bacterial community responded similarly to both sources with a 2-fold increase in bacterial abundance compared to the control. Unlike the bacterial response, there was little difference in chlorophyll a concentrations between treatments, indicating that phytoplankton growth was not stimulated or inhibited by our additions.

  2. Diatoms and bacteria diversity: study of their relationships in the Southern Adriatic Sea

    Directory of Open Access Journals (Sweden)

    C. CAROPPO

    2003-12-01

    Full Text Available In the Southern Adriatic Sea (Italian coasts bacterial and diatom diversity was studied over an annual cycle and the relationships between these two microbial components were analyzed. As regards the culturable heterotrophic bacteria, Aeromonas was the predominant genus among the Gram-negative bacteria. The presence of Enterobacteriaceae, Cytophaga, Pseudomonas, Acinetobacterand Photobacteriumwas also remarkable. Flexibacter, Moraxella, Chromobacterium, Flavobacteriumand Vibriowere present at less than 5%. Of the 92 diatom species determined, 16 were the most abundant representing the 96% of this phytoplankton group. The results obtained demonstrated that several bacterial genera were significantly related to the most abundant and representative diatoms ( Chaetocerosspp., Pseudo-nitzschia pseudodelicatissimaand Rhizosoleniaspp..

  3. Veneno amnésico en especies de Pseudo-Nitzchia en la costa central del Perú y su riesgo para la acuicultura de pectínidos

    OpenAIRE

    Tenorio García Blásquez, Liz Cecil

    2014-01-01

    Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Acuicultura Se evaluó la presencia del veneno amnésico (intoxicación por ácido domoico) en la costa central del Perú, causante de problemas gastrointestinales, amnesia parcial y en algunos casos la muerte del ser humano, por la ingestión de moluscos contaminados por algunas microalgas del género Pseudo-nitzschia productora de esta toxina. En nuestro país se tiene registro de estas especies al igual que en otros países...

  4. Inorganic carbon acquisition in potentially toxic and non-toxic diatoms: the effect of pH-induced changes in the seawater carbonate chemistry

    DEFF Research Database (Denmark)

    Trimborn, S; Lundholm, Nina; Thoms, S

    2008-01-01

    The effects of pH-induced changes in seawater carbonate chemistry on inorganic carbon (C-i) acquisition and domoic acid (DA) production were studied in two potentially toxic diatom species, Pseudo-nitzschia multiseries and Nitzschia navis-varingica, and the non-toxic Stellarima stellaris. In vivo......H. In terms of carbon source, all species took up both CO2 and HCO3-. K-1/2 values for inorganic carbon uptake decreased with increasing pH in two species, while in N. navis-varingica apparent affinities did not change. While the contribution of HCO3- to net fixation was more than 85% in S. stellaris...

  5. Morphological and physiological effects in proboscia alata (bacillariophyceae) grown under different light and CO2 conditions of the modern Southern ocean

    NARCIS (Netherlands)

    Hoogstraten, Astrid; Timmermans, Klaas R.; de Baar, Hein J. W.

    The combined effects of different light and aqueous CO2 conditions were assessed for the Southern Ocean diatom Proboscia alata (Brightwell) Sundstrom in laboratory experiments. Selected culture conditions (light and CO2(aq)) were representative for the natural ranges in the modern Southern Ocean.

  6. EXPANSION OF DIDYMOSPHENIA GEMINATA (LYNGBE M. SCHMIDT (BACILLARIOPHYCEAE IN RUNNING WATERS IN S-E POLAND: NEW RECORDS IN THE PODKARPACIE REGION

    Directory of Open Access Journals (Sweden)

    Teresa Noga

    2014-04-01

    Full Text Available Nowadays Didymosphenia geminata is one of the most frequently studied diatoms in the world, due to its massive development in most continents. In Poland, up to the 1990’s only a small number of specimens were recorded, from streams in the Tatra Mountains and the Dunajec River. D. geminata was found in 2007–2008 in the middle and upper sections of the Wisłok River, while in 2009 and 2011 it was also found in the Wisłoka, Ropa, Bielcza, and San. The cells belonged to one morphotype “geminata” and were characterized by high variability of size. It develops in mesotrophic, well-oxygenated, upper parts of flowing waters with rapid currents. It was most abundant below reservoirs on the San, Wisłok and Wisłoka.

  7. EXPANSION OF DIDYMOSPHENIA GEMINATA (LYNGBE) M. SCHMIDT (BACILLARIOPHYCEAE) IN RUNNING WATERS IN S-E POLAND: NEW RECORDS IN THE PODKARPACIE REGION

    OpenAIRE

    Teresa Noga; Jadwiga Stanek-Tarkowska; Anita Pajączek; Łukasz Peszek; Natalia Kochman

    2014-01-01

    Nowadays Didymosphenia geminata is one of the most frequently studied diatoms in the world, due to its massive development in most continents. In Poland, up to the 1990’s only a small number of specimens were recorded, from streams in the Tatra Mountains and the Dunajec River. D. geminata was found in 2007–2008 in the middle and upper sections of the Wisłok River, while in 2009 and 2011 it was also found in the Wisłoka, Ropa, Bielcza, and San. The cells belonged to one morphotype “geminata” a...

  8. CHANGES IN CHLOROPHYLL A FLUORENSCENCE AND PIGMENT RATIOS DURING DIFFERENT GROWTH PHASES OF A UNICELLULAR MARINE CHEATOSEROS (BACILLARIOPHYCEAE) IN BATCH CULTURE

    Science.gov (United States)

    Photosystem II reaction centers per cell decreased as the cultures began to decline. The degree of inactivation increased daily as the cell numbers continued to decrease. The concentration of chlorophyll a per cell and the ratio of the major accessory pigments to chlorophyll a (e...

  9. The species concept in a marine diatom: LSU rDNA–based phylogenetic differentiation in Skeletonema marinoi/dohrnii (Bacillariophyceae) is not reflected in morphology

    DEFF Research Database (Denmark)

    Ellegaard, Marianne; Godhe, Anna; Härnström, Karolina

    2008-01-01

    and Canada) included in the study showed differences in LSU rDNA sequence within the morphospecies, with differences seen even among clones established from a single plankton net sample. Morphologically, all clones were indistinguishable from each other and from the closely related species Skeletonema...... dohrnii. In the original description of these two species, they were differentiated by the structure of the girdle bands. However, the girdle band types of both species were found within single samples of almost all clones of S. marinoi in this study. The LSU-based phylogeny is consistent with the split...... and DNA sequence analysis, and such questions are addressed here....

  10. Differential effects of changes in spectral irradiance on photoacclimation, primary productivity and growth in Rhodomonas salina (Cryptophyceae) and Skeletonema costatum (Bacillariophyceae) in simulated blackwater environments.

    Science.gov (United States)

    Lawrenz, Evelyn; Richardson, Tammi L

    2017-12-01

    The underwater light field in blackwater environments is strongly skewed toward the red end of the electromagnetic spectrum due to blue light absorption by colored dissolved organic matter (CDOM). Exposure of phytoplankton to full spectrum irradiance occurs only when cells are mixed up to the surface. We studied the potential effects of mixing-induced changes in spectral irradiance on photoacclimation, primary productivity and growth in cultures of the cryptophyte Rhodomonas salina and the diatom Skeletonema costatum. We found that these taxa have very different photoacclimation strategies. While S. costatum showed classical complementary chromatic adaption, R. salina showed inverse chromatic adaptation, a strategy previously unknown in the cryptophytes. Transfer of R. salina to periodic full spectrum light (PFSL) significantly enhanced growth rate (μ) by 1.8 times and primary productivity from 0.88 to 1.35 mg C · (mg Chl-1 ) · h-1 . Overall, R. salina was less dependent on PFSL than was S. costatum, showing higher μ and net primary productivity rates. In the high-CDOM simulation, carbon metabolism of the diatom was impaired, leading to suppression of growth rate, short-term 14 C uptake and net primary production. Upon transfer to PFSL, μ of the diatom increased by up to 3-fold and carbon fixation from 2.4 to 6.0 mg C · (mg Chl-1 ) · h-1 . Thus, a lack of PFSL differentially impairs primarily CO2 -fixation and/or carbon metabolism, which, in turn, may determine which phytoplankton dominate the community in blackwater habitats and may therefore influence the structure and function of these ecosystems. © 2017 Phycological Society of America.

  11. Chattonella (Raphidophyceae) bloom spatio-temporal variations in Tachibana Bay and the southern area of Ariake Sea, Japan: Interregional displacement patterns with Skeletonema (Bacillariophyceae).

    Science.gov (United States)

    Aoki, Kazuhiro; Onitsuka, Goh; Shimizu, Manabu; Yamatogi, Toshifumi; Ishida, Naoya; Kitahara, Shigeru; Hirano, Keiji

    2015-10-15

    In 2010, a massive bloom of the raphidophycean flagellate Chattonella occurred in the Ariake Sea and Tachibana Bay. Bloom dynamics and hydrographical conditions were examined by field survey. The development and decline of the bloom occurred three times in Tachibana Bay. First and third bloom developments synchronized with precipitation, and the second bloom developed in synchronization with a salinity decrease which occurred in relation to an increase of river discharge from the Chikugo River which takes several days to flow from the Ariake Sea. These results imply that the bloom was transported with the low salinity water from the Ariake Sea to Tachibana Bay. During blooms along the northern coast of Shimabara Peninsula, the predominant phytoplankton species changed from Chattonella to Skeletonema. Low salinity water intrusion induced an interregional difference of the Chattonella and Skeletonema bloom spatially-differentiated by the salinity in the Ariake Sea and Tachibana Bay. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Nutrient limitation and high irradiance acclimation reduce PAR and UV-induced viability loss in the Antarctic diatom Chaetoceros brevis (Bacillariophyceae)

    NARCIS (Netherlands)

    van de Poll, WH; van Leeuwe, MA; Roggeveld, J; Buma, AGJ

    The effects of high PAR (400-700 nm), UVA (315-400 nm), and UVB (280-315 nm) radiation on viability and photosynthesis were investigated for Chaetoceros brevis Schutt. This Antarctic marine diatom was cultivated under low, medium, and high irradiance and nitrate, phosphate, silicate, and iron

  13. From sanddabs to blue whales: the pervasiveness of domoic acid.

    Science.gov (United States)

    Lefebvre, Kathi A; Bargu, Sibel; Kieckhefer, Tom; Silver, Mary W

    2002-07-01

    Domoic acid (DA) is a potent food web transferred algal toxin that has caused dramatic mortality events involving sea birds and sea lions. Although no confirmed DA toxicity events have been reported in whales, here we present data demonstrating that humpback and blue whales are exposed to the toxin and consume DA contaminated prey. Whale fecal samples were found to contain DA at levels ranging from 10 to 207microg DA g(-1) feces via HPLC-UV methods. SEM analysis of whale feces containing DA, collected from krill-feeding whales, revealed the presence of diatom frustules identified as Pseudo-nitzschia australis, a known DA producer. Humpback whales were observed feeding on anchovies and sardines that contained DA at levels ranging from 75 to 444microg DA g(-1) viscera. DA contamination of whale feces and fish occurred only during blooms of toxic Pseudo-nitzschia. Additionally, several novel fish species collected during a toxic diatom bloom were tested for DA. Fish as diverse as benthic sanddabs and pelagic albacore were found to contain the neurotoxin, suggesting that DA permeates benthic as well as pelagic communities.

  14. The risk of harmful algal blooms (HABs) in the oyster-growing estuaries of New South Wales, Australia.

    Science.gov (United States)

    Ajani, Penelope; Brett, Steve; Krogh, Martin; Scanes, Peter; Webster, Grant; Armand, Leanne

    2013-06-01

    The spatial and temporal variability of potentially harmful phytoplankton was examined in the oyster-growing estuaries of New South Wales. Forty-five taxa from 31 estuaries were identified from 2005 to 2009. Harmful species richness was latitudinally graded for rivers, with increasing number of taxa southward. There were significant differences (within an estuary) in harmful species abundance and richness for 11 of 21 estuaries tested. Where differences were observed, these were predominately due to species belonging to the Pseudo-nitzschia delicatissima group, Dinophysis acuminata, Dictyocha octonaria and Prorocentrum cordatum with a consistent upstream versus downstream pattern emerging. Temporal (seasonal or interannual) patterns in harmful phytoplankton within and among estuaries were highly variable. Examination of harmful phytoplankton in relation to recognised estuary disturbance measures revealed species abundance correlated to estuary modification levels and flushing time, with modified, slow flushing estuaries having higher abundance. Harmful species richness correlated with bioregion, estuary modification levels and estuary class, with southern, unmodified lakes demonstrating greater species density. Predicting how these risk taxa and risk zones may change with further estuary disturbance and projected climate warming will require more focused, smaller scale studies aimed at a deeper understanding of species-specific ecology and bloom mechanisms. Coupled with this consideration, there is an imperative for further taxonomic, ecological and toxicological investigations into poorly understood taxa (e.g. Pseudo-nitzschia).

  15. Influence of diatom exopolymers and biofilms on metamorphosis in the barnacle Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

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

    Natural biofilms constitute a complex network of microorganisms (bacteria, diatoms, protozoa, fungi) and their extracellular polymeric substances (EPS), which influence settlement inbenthic invertebrates. The influence of diatom (Bacillariophyceae...

  16. Monitoring Domoic Acid production by Solid Phase Adsorption Toxin Tracking off the Santa Cruz Municipal Warf, Santa Cruz, California

    Science.gov (United States)

    Nolan, M.; Ziccarelli, L.; Kudela, R. M.

    2013-12-01

    Certain species of the diatom genus Pseudo-nitzschia are producers of the neurotoxin, domoic acid (DA). DA is known to cause amnesic shellfish poisoning also known as domoic acid poisoning, which can lead to permanent brain damage in humans and marine mammals. DA accumulates at higher trophic levels, generally due to consumption of toxic cells or through trophic transfer, and can potentially cause death of both humans and marine wildlife. The Santa Cruz Municipal Warf experiences periodic rises in DA concentrations, which can reach toxic levels in shellfish, fish, and other marine organisms. While these increases in toxicity often occur during Pseudo-nitzschia blooms, several periods of elevated DA have occurred when diatom abundance is restricted and/or dominated by non-toxic species, and there is increasing evidence that DA dissolved in seawater may be prevalent. One theory suggests that senescent or dead Pseudo-nitzschia cells sink to the benthos while retaining their toxin and are buried in sediment following the death of a bloom. Therefore, DA may accumulate in the benthos, where it is eventually released during storms or wave and tide conditions that disturb the sediment. We sampled DA in situ using Solid Phase Adsorption Toxin Tracking (SPATT) bags SPATT uses a synthetic resin to capture dissolved DA, allowing for the determination of integrated DA concentrations at known time intervals. The alternative method is mussel biotoxin monitoring, but it is less accurate due to uncertainties in the time of DA accumulation within the mussel, and the lack of uptake of dissolved DA by the mussel. We deployed and collected SPATT off the Santa Cruz Municipal Wharf at multiple depths beginning in February 2013. We expect to see increasing DA following the death of a harmful algal bloom. Under pre-bloom conditions, little to no DA has been detected in mussels or surface SPATT, but DA from SPATT is frequently observed at depth, suggesting that the sediment is exposed to

  17. Phytoplankton-associated bacterial community composition and succession during toxic diatom bloom and non-bloom events

    Directory of Open Access Journals (Sweden)

    Marilou P. Sison-Mangus

    2016-09-01

    Full Text Available Pseudo-nitzschia blooms often occur in coastal and open ocean environments, sometimes leading to the production of the neurotoxin domoic acid that can cause severe negative impacts to higher trophic levels. Increasing evidence suggests a close relationship between phytoplankton bloom and bacterial assemblages, however, the microbial composition and succession during a bloom process is unknown. Here, we investigate the bacterial assemblages before, during and after toxic and non-toxic Pseudo-nitzschia blooms to determine the patterns of bacterial succession in a natural bloom setting. Opportunistic sampling of bacterial community profiles were determined weekly at Santa Cruz Municipal Wharf by 454 pyrosequencing and analyzed together with domoic acid levels, phytoplankton community and biomass, nutrients and temperature. We asked if the bacterial communities are similar between bloom and non-bloom events and if domoic acid or the presence of toxic algal species acts as a driving force that can significantly structure phytoplankton-associated bacterial communities. We found that bacterial diversity generally increases when Pseudo-nitzschia numbers decline. Furthermore, bacterial diversity is higher when the low-DA producing P. fraudulenta dominates the algal bloom while bacterial diversity is lower when high-DA producing P. australis dominates the algal bloom, suggesting that the presence of algal toxin can structure bacterial community. We also found bloom-related succession patterns among associated bacterial groups; Gamma-proteobacteria, were dominant during low toxic P. fraudulenta blooms comprising mostly of Vibrio spp., which increased in relative abundance (6%-65% as the bloom progresses. On the other hand, Firmicutes bacteria comprising mostly of Planococcus spp. (12%- 86% dominate during high toxic P. australis blooms, with the bacterial assemblage showing the same bloom-related successional patterns in 3 independent bloom events. Other

  18. Occurrence of four species of algae in the marine water of Hong Kong.

    Science.gov (United States)

    Chai, Yemao; Deng, Wen-Jing; Qin, Xing; Xu, Xiangrong

    2017-11-30

    Harmful algal blooms (HABs) have broken out frequently throughout the world in recent decades; they are caused by the rapid multiplication of algal cells in near-coastal waters polluted with nitrogen and phosphorus and greatly affect the quality of marine water and human health. Over the past several decades, climate change and increasing environmental degradation have provided favourable growth conditions for certain phytoplankton species. Therefore, it is essential to rapidly identify and enumerate harmful marine algae to control these species. In this study, quantitative PCR (qPCR) was used to detect four representative species of HABs that are widespread in the marine water of Hong Kong, namely, Alexandrium catenella, Pseudo-nitzschia spp., Karenia mikimotoi and Heterosigma akashiwo. We applied qPCR with the dye SYBR Green to detect Alexandrium spp. and Pseudo-nitzschia spp. and used TaqMan probe for the enumeration of Karenia mikimotoi and Heterosigma akashiwo. The total genomic DNA of these algae from Hong Kong marine water was extracted successfully using the CTAB method, and for each kind of alga, we constructed a ten-fold series of recombinant plasmid solutions containing certain gene fragments of 18S rDNA and ITS1-5.8S-ITS2 as standard samples. Ten-fold dilutions of the DNA of known numbers of the extracted algal cells were also used to create an additional standard curve. In this way, the relationship between the cell number and the related plasmid copy number was established. The qPCR assay displayed high sensitivity in monitoring marine water samples in which the low concentrations of harmful algae were not detected accurately by traditional methods. The results showed that the cell numbers of the four species were all in low abundance. For Alexandrium catenella, the cell abundances at 12 sites ranged from 3.8×102 to 4.3×103cellsL-1, while H. akashiwo, K. mikimotoi and Pseudo-nitzschia ranged from 1.1×102 to 1.3×103, from 23 to 6.5×102 and from 45

  19. 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.

  20. Domoic acid excretion in dungeness crabs, razor clams and mussels.

    Science.gov (United States)

    Schultz, Irvin R; Skillman, Ann; Woodruff, Dana

    2008-07-01

    Domoic acid (DA) is a neurotoxic amino acid produced by several marine algal species of the Pseudo-nitzschia (PN) genus. We studied the elimination of DA from hemolymph after intravascular (IV) injection in razor clams (Siliqua patula), mussels (Mytilus edulis) and Dungeness crabs (Cancer magister). Crabs were also injected with two other organic acids, dichloroacetic acid (DCAA) and kainic acid (KA). For IV dosing, hemolymph was repetitively sampled and DA concentrations measured by HPLC-UV. Toxicokinetic analysis of DA in crabs suggested most of the injected dose remained within hemolymph compartment with little extravascular distribution. This observation is in sharp contrast to results obtained from clams and mussels which exhibited similarly large apparent volumes of distribution despite large differences in overall clearance. These findings suggest fundamentally different storage and elimination processes are occurring for DA between bivalves and crabs.

  1. Arctic Diatoms - Diversity, Plankton Interactions and Poulation Dynamics

    DEFF Research Database (Denmark)

    Tammilehto, Anna

    Oceans produce nearly half of the global net primary production annually. Most productive marine areas are found along coasts and, contrary to the terrestrial ecosystems, at high latitudes. In these areas most primary production is done by phytoplankton. In the Arctic, phytoplankton communities...... are often dominated by diatoms. They are single-celled, eukaryotic algae, which play an essential role in ocean carbon and silica cycles. Many species of the diatom genus Pseudo-nitzschia Peragallo produce a neurotoxin, domoic acid (DA), which can be transferred to higher levels in food webs causing amnesic...... that blooming behavior may be beneficial for F. cylindrus. High genetic diversity found in F. cylindrus coupled with high ecophysiological variability (i.e. variation among the strains and phenotypic plasticity) with regard to projected increase in temperature and decrease in pH due to climate change suggests...

  2. A Diatom Ferritin Optimized for Iron Oxidation but Not Iron Storage*

    Science.gov (United States)

    Pfaffen, Stephanie; Bradley, Justin M.; Abdulqadir, Raz; Firme, Marlo R.; Moore, Geoffrey R.; Le Brun, Nick E.; Murphy, Michael E. P.

    2015-01-01

    Ferritin from the marine pennate diatom Pseudo-nitzschia multiseries (PmFTN) plays a key role in sustaining growth in iron-limited ocean environments. The di-iron catalytic ferroxidase center of PmFTN (sites A and B) has a nearby third iron site (site C) in an arrangement typically observed in prokaryotic ferritins. Here we demonstrate that Glu-44, a site C ligand, and Glu-130, a residue that bridges iron bound at sites B and C, limit the rate of post-oxidation reorganization of iron coordination and the rate at which Fe3+ exits the ferroxidase center for storage within the mineral core. The latter, in particular, severely limits the overall rate of iron mineralization. Thus, the diatom ferritin is optimized for initial Fe2+ oxidation but not for mineralization, pointing to a role for this protein in buffering iron availability and facilitating iron-sparing rather than only long-term iron storage. PMID:26396187

  3. Is Occurrence of Harmful Algal Blooms in the Exclusive Economic Zone of India on the Rise?

    Directory of Open Access Journals (Sweden)

    K. B. Padmakumar

    2012-01-01

    Full Text Available Occurrence, increase in frequency, intensity and spatial coverage of harmful algal blooms during the past decade in the EEZ of India are documented here. Eighty algal blooms were recorded during the period 1998–2010. Of the eighty algal blooms, 31 blooms were formed by dinoflagellates, 27 by cyanobacteria, and 18 by diatoms. Three raphidophyte and one haptophyte blooms were also observed. Potentially toxic microalgae recorded from the Indian waters were Alexandrium spp., Gymnodinium spp. Dinophysis spp., Coolia monotis, Prorocentrum lima, and Pseudo-nitzschia spp. Examination of available data from the literature during the last hundred years and in situ observations during 1998–2010 indicates clear-cut increase in the occurrence of HABs in the Indian EEZ.

  4. Applications of Satellite Ocean Color Imagery for Detecting and Monitoring Harmful Algal Blooms in the Olympic Peninsula Region

    Energy Technology Data Exchange (ETDEWEB)

    Holt, Ashley C.; Stumpf, Richard P.; Tomlinson, Michelle C.; Ransibrahmanakul, Varis; Trainer, Vera L.; Woodruff, Dana L.

    2003-08-01

    Harmful algal blooms (HABs) attributed to Pseudo-nitzschia species, a diatom that produces Domoic acid, are a common occurrence and serious threat along the coast of the US Northwest. Monitoring these events or providing advanced warning of their occurrence at the coast would provide an important aid to fisheries managers. Remote sensing, which is being used in the Gulf of Mexico for HAB detection and forecasting (of a different algae), could provide a tool for monitoring and warnings. Chlorophyll and SST imagery are being used to support a research and monitoring program for the region, and HAB monitoring techniques used in the Gulf of Mexico are being examined for their potential utility along the Washington coast. The focus of this study is to determine the efficacy of using satellite ocean color imagery for HAB monitoring off of Washingtons Olympic Peninsula region, and to provide support in the form of ocean color imagery products for management and mitigation efforts.

  5. Causality of an extreme harmful algal bloom in Monterey Bay, California, during the 2014-2016 northeast Pacific warm anomaly

    Science.gov (United States)

    Ryan, J. P.; Kudela, R. M.; Birch, J. M.; Blum, M.; Bowers, H. A.; Chavez, F. P.; Doucette, G. J.; Hayashi, K.; Marin, R.; Mikulski, C. M.; Pennington, J. T.; Scholin, C. A.; Smith, G. J.; Woods, A.; Zhang, Y.

    2017-06-01

    An ecologically and economically disruptive harmful algal bloom (HAB) affected much of the northeast Pacific margin in 2015, during a prolonged oceanic warm anomaly. Caused by diatoms of the genus Pseudo-nitzschia, this HAB produced the highest particulate concentrations of the biotoxin domoic acid (DA) ever recorded in Monterey Bay, California. Bloom inception followed strong upwelling during the spring transition, which introduced nutrients and eliminated the warm anomaly locally. Subsequently, moderate and intermittent upwelling created favorable conditions for growth and accumulation of HAB biomass, which was dominated by a highly toxigenic species, P. australis. High cellular DA concentrations were associated with available nitrogen for DA synthesis coincident with silicate exhaustion. This nutrient influence resulted from two factors: (1) disproportionate depletion of silicate in upwelling source waters during the warm anomaly, the most severe depletion observed in 24 years, and (2) silicate uptake by the dense diatom bloom.

  6. The role of domoic acid in abortion and premature parturition of California sea lions (Zalophus californianus) on San Miguel Island, California.

    Science.gov (United States)

    Goldstein, Tracey; Zabka, Tanja S; Delong, Robert L; Wheeler, Elizabeth A; Ylitalo, Gina; Bargu, Sibel; Silver, Mary; Leighfield, Tod; Van Dolah, Frances; Langlois, Gregg; Sidor, Inga; Dunn, J Lawrence; Gulland, Frances M D

    2009-01-01

    Domoic acid is a glutaminergic neurotoxin produced by marine algae such as Pseudo-nitzschia australis. California sea lions (Zalophus californianus) ingest the toxin when foraging on planktivorous fish. Adult females comprise 60% of stranded animals admitted for rehabilitation due to acute domoic acid toxicosis and commonly suffer from reproductive failure, including abortions and premature live births. Domoic acid has been shown to cross the placenta exposing the fetus to the toxin. To determine whether domoic acid was playing a role in reproductive failure in sea lion rookeries, 67 aborted and live-born premature pups were sampled on San Miguel Island in 2005 and 2006 to investigate the causes for reproductive failure. Analyses included domoic acid, contaminant and infectious disease testing, and histologic examination. Pseudo-nitzschia spp. were present both in the environment and in sea lion feces, and domoic acid was detected in the sea lion feces and in 17% of pup samples tested. Histopathologic findings included systemic and localized inflammation and bacterial infections of amniotic origin, placental abruption, and brain edema. The primary lesion in five animals with measurable domoic acid concentrations was brain edema, a common finding and, in some cases, the only lesion observed in aborted premature pups born to domoic acid-intoxicated females in rehabilitation. Blubber organochlorine concentrations were lower than those measured previously in premature sea lion pups collected in the 1970s. While the etiology of abortion and premature parturition was varied in this study, these results suggest that domoic acid contributes to reproductive failure on California sea lion rookeries.

  7. Comparative Analysis of Three Brevetoxin-Associated Bottlenose Dolphin (Tursiops truncatus) Mortality Events in the Florida Panhandle Region (USA)

    Science.gov (United States)

    Twiner, Michael J.; Flewelling, Leanne J.; Fire, Spencer E.; Bowen-Stevens, Sabrina R.; Gaydos, Joseph K.; Johnson, Christine K.; Landsberg, Jan H.; Leighfield, Tod A.; Mase-Guthrie, Blair; Schwacke, Lori; Van Dolah, Frances M.; Wang, Zhihong; Rowles, Teresa K.

    2012-01-01

    In the Florida Panhandle region, bottlenose dolphins (Tursiops truncatus) have been highly susceptible to large-scale unusual mortality events (UMEs) that may have been the result of exposure to blooms of the dinoflagellate Karenia brevis and its neurotoxin, brevetoxin (PbTx). Between 1999 and 2006, three bottlenose dolphin UMEs occurred in the Florida Panhandle region. The primary objective of this study was to determine if these mortality events were due to brevetoxicosis. Analysis of over 850 samples from 105 bottlenose dolphins and associated prey items were analyzed for algal toxins and have provided details on tissue distribution, pathways of trophic transfer, and spatial-temporal trends for each mortality event. In 1999/2000, 152 dolphins died following extensive K. brevis blooms and brevetoxin was detected in 52% of animals tested at concentrations up to 500 ng/g. In 2004, 105 bottlenose dolphins died in the absence of an identifiable K. brevis bloom; however, 100% of the tested animals were positive for brevetoxin at concentrations up to 29,126 ng/mL. Dolphin stomach contents frequently consisted of brevetoxin-contaminated menhaden. In addition, another potentially toxigenic algal species, Pseudo-nitzschia, was present and low levels of the neurotoxin domoic acid (DA) were detected in nearly all tested animals (89%). In 2005/2006, 90 bottlenose dolphins died that were initially coincident with high densities of K. brevis. Most (93%) of the tested animals were positive for brevetoxin at concentrations up to 2,724 ng/mL. No DA was detected in these animals despite the presence of an intense DA-producing Pseudo-nitzschia bloom. In contrast to the absence or very low levels of brevetoxins measured in live dolphins, and those stranding in the absence of a K. brevis bloom, these data, taken together with the absence of any other obvious pathology, provide strong evidence that brevetoxin was the causative agent involved in these bottlenose dolphin mortality

  8. Comparative analysis of three brevetoxin-associated bottlenose dolphin (Tursiops truncatus mortality events in the Florida Panhandle region (USA.

    Directory of Open Access Journals (Sweden)

    Michael J Twiner

    Full Text Available In the Florida Panhandle region, bottlenose dolphins (Tursiops truncatus have been highly susceptible to large-scale unusual mortality events (UMEs that may have been the result of exposure to blooms of the dinoflagellate Karenia brevis and its neurotoxin, brevetoxin (PbTx. Between 1999 and 2006, three bottlenose dolphin UMEs occurred in the Florida Panhandle region. The primary objective of this study was to determine if these mortality events were due to brevetoxicosis. Analysis of over 850 samples from 105 bottlenose dolphins and associated prey items were analyzed for algal toxins and have provided details on tissue distribution, pathways of trophic transfer, and spatial-temporal trends for each mortality event. In 1999/2000, 152 dolphins died following extensive K. brevis blooms and brevetoxin was detected in 52% of animals tested at concentrations up to 500 ng/g. In 2004, 105 bottlenose dolphins died in the absence of an identifiable K. brevis bloom; however, 100% of the tested animals were positive for brevetoxin at concentrations up to 29,126 ng/mL. Dolphin stomach contents frequently consisted of brevetoxin-contaminated menhaden. In addition, another potentially toxigenic algal species, Pseudo-nitzschia, was present and low levels of the neurotoxin domoic acid (DA were detected in nearly all tested animals (89%. In 2005/2006, 90 bottlenose dolphins died that were initially coincident with high densities of K. brevis. Most (93% of the tested animals were positive for brevetoxin at concentrations up to 2,724 ng/mL. No DA was detected in these animals despite the presence of an intense DA-producing Pseudo-nitzschia bloom. In contrast to the absence or very low levels of brevetoxins measured in live dolphins, and those stranding in the absence of a K. brevis bloom, these data, taken together with the absence of any other obvious pathology, provide strong evidence that brevetoxin was the causative agent involved in these bottlenose dolphin

  9. Concurrent exposure of bottlenose dolphins (Tursiops truncatus) to multiple algal toxins in Sarasota Bay, Florida, USA.

    Science.gov (United States)

    Twiner, Michael J; Fire, Spencer; Schwacke, Lori; Davidson, Leigh; Wang, Zhihong; Morton, Steve; Roth, Stephen; Balmer, Brian; Rowles, Teresa K; Wells, Randall S

    2011-03-10

    Sentinel species such as bottlenose dolphins (Tursiops truncatus) can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA), the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs) of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX) produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA). Over a ten-year study period (2000-2009) we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009) with 36% of all animals testing positive for brevetoxin (n = 118) and 53% positive for DA (n = 83) with several individuals (14%) testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p = 0.001) and eosinophil (pdolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health.

  10. Comparative analysis of three brevetoxin-associated bottlenose dolphin (Tursiops truncatus) mortality events in the Florida Panhandle region (USA).

    Science.gov (United States)

    Twiner, Michael J; Flewelling, Leanne J; Fire, Spencer E; Bowen-Stevens, Sabrina R; Gaydos, Joseph K; Johnson, Christine K; Landsberg, Jan H; Leighfield, Tod A; Mase-Guthrie, Blair; Schwacke, Lori; Van Dolah, Frances M; Wang, Zhihong; Rowles, Teresa K

    2012-01-01

    In the Florida Panhandle region, bottlenose dolphins (Tursiops truncatus) have been highly susceptible to large-scale unusual mortality events (UMEs) that may have been the result of exposure to blooms of the dinoflagellate Karenia brevis and its neurotoxin, brevetoxin (PbTx). Between 1999 and 2006, three bottlenose dolphin UMEs occurred in the Florida Panhandle region. The primary objective of this study was to determine if these mortality events were due to brevetoxicosis. Analysis of over 850 samples from 105 bottlenose dolphins and associated prey items were analyzed for algal toxins and have provided details on tissue distribution, pathways of trophic transfer, and spatial-temporal trends for each mortality event. In 1999/2000, 152 dolphins died following extensive K. brevis blooms and brevetoxin was detected in 52% of animals tested at concentrations up to 500 ng/g. In 2004, 105 bottlenose dolphins died in the absence of an identifiable K. brevis bloom; however, 100% of the tested animals were positive for brevetoxin at concentrations up to 29,126 ng/mL. Dolphin stomach contents frequently consisted of brevetoxin-contaminated menhaden. In addition, another potentially toxigenic algal species, Pseudo-nitzschia, was present and low levels of the neurotoxin domoic acid (DA) were detected in nearly all tested animals (89%). In 2005/2006, 90 bottlenose dolphins died that were initially coincident with high densities of K. brevis. Most (93%) of the tested animals were positive for brevetoxin at concentrations up to 2,724 ng/mL. No DA was detected in these animals despite the presence of an intense DA-producing Pseudo-nitzschia bloom. In contrast to the absence or very low levels of brevetoxins measured in live dolphins, and those stranding in the absence of a K. brevis bloom, these data, taken together with the absence of any other obvious pathology, provide strong evidence that brevetoxin was the causative agent involved in these bottlenose dolphin mortality

  11. Iron limitation modulates ocean acidification effects on southern ocean phytoplankton communities.

    Science.gov (United States)

    Hoppe, Clara J M; Hassler, Christel S; Payne, Christopher D; Tortell, Philippe D; Rost, Björn; Trimborn, Scarlett

    2013-01-01

    The potential interactive effects of iron (Fe) limitation and Ocean Acidification in the Southern Ocean (SO) are largely unknown. Here we present results of a long-term incubation experiment investigating the combined effects of CO2 and Fe availability on natural phytoplankton assemblages from the Weddell Sea, Antarctica. Active Chl a fluorescence measurements revealed that we successfully cultured phytoplankton under both Fe-depleted and Fe-enriched conditions. Fe treatments had significant effects on photosynthetic efficiency (Fv/Fm; 0.3 for Fe-depleted and 0.5 for Fe-enriched conditions), non-photochemical quenching (NPQ), and relative electron transport rates (rETR). pCO2 treatments significantly affected NPQ and rETR, but had no effect on Fv/Fm. Under Fe limitation, increased pCO2 had no influence on C fixation whereas under Fe enrichment, primary production increased with increasing pCO2 levels. These CO2-dependent changes in productivity under Fe-enriched conditions were accompanied by a pronounced taxonomic shift from weakly to heavily silicified diatoms (i.e. from Pseudo-nitzschia sp. to Fragilariopsis sp.). Under Fe-depleted conditions, this functional shift was absent and thinly silicified species dominated all pCO2 treatments (Pseudo-nitzschia sp. and Synedropsis sp. for low and high pCO2, respectively). Our results suggest that Ocean Acidification could increase primary productivity and the abundance of heavily silicified, fast sinking diatoms in Fe-enriched areas, both potentially leading to a stimulation of the biological pump. Over much of the SO, however, Fe limitation could restrict this possible CO2 fertilization effect.

  12. Iron Limitation Modulates Ocean Acidification Effects on Southern Ocean Phytoplankton Communities

    Science.gov (United States)

    Hoppe, Clara J. M.; Hassler, Christel S.; Payne, Christopher D.; Tortell, Philippe D.; Rost, Björn; Trimborn, Scarlett

    2013-01-01

    The potential interactive effects of iron (Fe) limitation and Ocean Acidification in the Southern Ocean (SO) are largely unknown. Here we present results of a long-term incubation experiment investigating the combined effects of CO2 and Fe availability on natural phytoplankton assemblages from the Weddell Sea, Antarctica. Active Chl a fluorescence measurements revealed that we successfully cultured phytoplankton under both Fe-depleted and Fe-enriched conditions. Fe treatments had significant effects on photosynthetic efficiency (Fv/Fm; 0.3 for Fe-depleted and 0.5 for Fe-enriched conditions), non-photochemical quenching (NPQ), and relative electron transport rates (rETR). pCO2 treatments significantly affected NPQ and rETR, but had no effect on Fv/Fm. Under Fe limitation, increased pCO2 had no influence on C fixation whereas under Fe enrichment, primary production increased with increasing pCO2 levels. These CO2-dependent changes in productivity under Fe-enriched conditions were accompanied by a pronounced taxonomic shift from weakly to heavily silicified diatoms (i.e. from Pseudo-nitzschia sp. to Fragilariopsis sp.). Under Fe-depleted conditions, this functional shift was absent and thinly silicified species dominated all pCO2 treatments (Pseudo-nitzschia sp. and Synedropsis sp. for low and high pCO2, respectively). Our results suggest that Ocean Acidification could increase primary productivity and the abundance of heavily silicified, fast sinking diatoms in Fe-enriched areas, both potentially leading to a stimulation of the biological pump. Over much of the SO, however, Fe limitation could restrict this possible CO2 fertilization effect. PMID:24278207

  13. Concurrent exposure of bottlenose dolphins (Tursiops truncatus to multiple algal toxins in Sarasota Bay, Florida, USA.

    Directory of Open Access Journals (Sweden)

    Michael J Twiner

    Full Text Available Sentinel species such as bottlenose dolphins (Tursiops truncatus can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA, the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA. Over a ten-year study period (2000-2009 we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009 with 36% of all animals testing positive for brevetoxin (n = 118 and 53% positive for DA (n = 83 with several individuals (14% testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p = 0.001 and eosinophil (p<0.001 counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health.

  14. Concurrent Exposure of Bottlenose Dolphins (Tursiops truncatus) to Multiple Algal Toxins in Sarasota Bay, Florida, USA

    Science.gov (United States)

    Twiner, Michael J.; Fire, Spencer; Schwacke, Lori; Davidson, Leigh; Wang, Zhihong; Morton, Steve; Roth, Stephen; Balmer, Brian; Rowles, Teresa K.; Wells, Randall S.

    2011-01-01

    Sentinel species such as bottlenose dolphins (Tursiops truncatus) can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA), the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs) of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX) produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA). Over a ten-year study period (2000–2009) we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009) with 36% of all animals testing positive for brevetoxin (n = 118) and 53% positive for DA (n = 83) with several individuals (14%) testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p = 0.001) and eosinophil (p<0.001) counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health. PMID:21423740

  15. Eosinophilia and biotoxin exposure in bottlenose dolphins (Tursiops truncatus) from a coastal area impacted by repeated mortality events

    Energy Technology Data Exchange (ETDEWEB)

    Schwacke, Lori H., E-mail: Lori.Schwacke@noaa.gov [National Oceanic and Atmospheric Administration, National Ocean Service, Center for Human Health Risks, 331 Fort Johnson Road, Charleston, SC 29412 (United States); Twiner, Michael J. [National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Road, Charleston, SC 29412 (United States); De Guise, Sylvain [University of Connecticut, Department of Pathobiology and Veterinary Science, 61 North Eagleville Road, U-89, Storrs, CT 06269 (United States); Balmer, Brian C.; Wells, Randall S. [Chicago Zoological Society, c/o Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 (United States); Townsend, Forrest I. [Bayside Hospital for Animals, 251 N.E. Racetrack Road, Fort Walton Beach, FL 32547 (United States); Rotstein, David C. [National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, Marine Mammal Health and Stranding Response Program, 1315 East West Highway, Silver Spring, MD 20910 (United States); Varela, Rene A. [Ocean Embassy Inc, 6433 Pinecastle Blvd, Ste 2, Orlando, FL 32809 (United States); Hansen, Larry J. [National Oceanic and Atmospheric Administration, National Marine Fisheries Service Southeast Fisheries Science Center,101 Pivers Island Road, Beaufort, NC 28516 (United States); Zolman, Eric S. [National Oceanic and Atmospheric Administration, National Ocean Service, Center for Coastal Environmental Health and Biomolecular Research, 219 Fort Johnson Road, Charleston, SC 29412 (United States); Spradlin, Trevor R. [National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, Marine Mammal Health and Stranding Response Program, 1315 East West Highway, Silver Spring, MD 20910 (United States); and others

    2010-08-15

    Bottlenose dolphins (Tursiops truncatus) inhabiting coastal waters in the northern Gulf of Mexico have been impacted by recurrent unusual mortality events over the past few decades. Several of these mortality events along the Florida panhandle have been tentatively attributed to poisoning from brevetoxin produced by the dinoflagellate Karenia brevis. While dolphins in other regions of the Florida coast are often exposed to K. brevis blooms, large-scale dolphin mortality events are relatively rare and the frequency and magnitude of die-offs along the Panhandle raise concern for the apparent vulnerability of dolphins in this region. We report results from dolphin health assessments conducted near St. Joseph Bay, Florida, an area impacted by 3 unusual die-offs within a 7-year time span. An eosinophilia syndrome, manifested as an elevated blood eosinophil count without obvious cause, was observed in 23% of sampled dolphins. Elevated eosinophil counts were associated with decreased T-lymphocyte proliferation and increased neutrophil phagocytosis. In addition, indication of chronic low-level exposure to another algal toxin, domoic acid produced by the diatom Pseudo-nitzschia spp., was determined. Previous studies of other marine mammal populations exposed recurrently to Pseudo-nitzschia blooms have suggested a possible link between the eosinophilia and domoic acid exposure. While the chronic eosinophilia syndrome could over the long-term produce organ damage and alter immunological status and thereby increase vulnerability to other challenges, the significance of the high prevalence of the syndrome to the observed mortality events in the St. Joseph Bay area is unclear. Nonetheless, the unusual immunological findings and concurrent evidence of domoic acid exposure in this sentinel marine species suggest a need for further investigation to elucidate potential links between chronic, low-level exposure to algal toxins and immune health.

  16. A Description of Biremis panamae sp. nov., a New Diatom Species from the Marine Littoral, with an Account of the Phylogenetic Position of Biremis D.G. Mann et E.J. Cox (Bacillariophyceae.

    Directory of Open Access Journals (Sweden)

    Andrzej Witkowski

    Full Text Available Here we present a formal description of Biremis panamae Barka, Witkowski et Weisenborn sp. nov., which was isolated from the marine littoral environment of the Pacific Ocean coast of Panama. The description is based on morphology (light and electron microscopy and the rbcL, psbC and SSU sequences of one clone of this species. The new species is included in Biremis due to its morphological features; i.e. two marginal rows of foramina, chambered striae, and girdle composed of numerous punctate copulae. The new species also possesses a striated valve face which is not seen in most known representatives of marine littoral Biremis species. In this study we also present the relationship of Biremis to other taxa using morphology, DNA sequence data and observations of auxosporulation. Our results based on these three sources point to an evolutionary relationship between Biremis, Neidium and Scoliopleura. The unusual silicified incunabular caps present in them are known otherwise only in Muelleria, which is probably related to the Neidiaceae and Scoliotropidaceae. We also discuss the relationship between Biremis and the recently described Labellicula and Olifantiella.

  17. Análise da estrutura da comunidade de diatomáceas (Bacillariophyceae em duas estações do sistema Guaíba, Rio Grande do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Eduardo A Lobo

    1987-12-01

    Full Text Available Através da análise da composição específica e da diversidade da comunidade de diatomáceas, em duas estações do sistema Guaíba (RS, Brasil, nos meses de setembro e novembro de 1975, foi encontrada uma diferença significativa na estrutura dessa comunidade. Essa diferença deve-se, provavelmente, à presença exclusiva de Achnanthes inflata (Kütz. Grun. var. elata (Leud. - Fort.Hust., A. lanceolata (Bréb.Grun. var. lanceolata, Cocconeis placentula Ehr., Cyclotella meneghiniana Kütz., Cymbella minuta Hilse ex Rabh., Aulacosira distans (Ehr. Sim., Navicula mutica Kütz., Surirella robusta Ehr. var. splendida (Ehr. Van Heurck, Synedra ulna (Nitz.Ehr., espécies abundantes, que refletem características ambientais distintas, pelo fato de apresentarem uma diferenciação em suas tolerâncias ecológicas. Foram identificados um total de 114 táxons, 57 a níveis específicos e infra-específicos, dentre os quais 14 constituem-se em primeira referência para o Guaíba e quatro são citações novas para o Estado.Through the analysis of specific composition and diversity of diatom community, in two sampling areas of the Guaíba system (RS, Brasil in September and October 1975, a meaningful difference in the structure of that community was found. Such difference is probably due to exclusive presence of Achnanthes inflata (Kütz.Grun. var. elata (Leud. - Fort.Hust., A. lanceolata(Bréb.Grun. var. lanceolata, Cocconeis placentula Ehr., Cyclotella meneghiniana Kütz., Cymbella minuta Hilse ex Rabh., and of Aulacosira distans(Ehr. Sim., Navicula mutica Kütz., Surirella robusta Ehr. var. splendida (Ehr.Van Heurck, Synedra ulna(Nitz.Ehr., abundant species which reflect different environmental characteristics because of their different ecological tolerances. A total of 114 taxa have been identified; 57 of them to specific and infraespecific levels, 14 of which mentioned for the first time in the Guaíba system and 4 for the first time in the state.

  18. Phytochemical Characterization And Biochemical Studies Of Cissus ...

    African Journals Online (AJOL)

    The leaves of cissus multistriata were collected, air-dried for two weeks and pulverized into powder; this was folowed by extraction with either chloroform or water The phytochemical screening of the extracts revealed the presence of carbohydrates, proteins, vitamin C, saponins, steroids, cardiac glycosides, lipids and ...

  19. Antimicrobial activity of the aqueous, methanol and chloroform leaf ...

    African Journals Online (AJOL)

    Antimicrobial activity of aqueous, methanol and chloroform leaf extracts of Cissus multistriata were investigated against 8 bacterial and 2 fungal test organisms, using the tube dilution and agar ditch diffusion methods. Aqueous leaf extract had no activity against both the bacterial and fungal test organisms. Both the methanol ...

  20. Diatom silicon biomineralization as an inspirational source of new approaches to silica production

    NARCIS (Netherlands)

    Vrieling, EG; Beelen, TPM; van Santen, RA; Gieskes, WWC

    1999-01-01

    The demand for new materials and products is still growing and the interest in naturally formed biopolymers and biominerals, such as chitin, calcium precipitates and silica is increasing. Photosynthesizing microalgae of the family Bacillariophyceae (diatoms) produce silica exoskeletons with a

  1. A shift in the dominant toxin-producing algal species in central California alters phycotoxins in food webs

    Science.gov (United States)

    Jester, R.; Lefebvre, K.; Langlois, G.; Vigilant, V.; Baugh, K.; Silver, M.W.

    2009-01-01

    In California, the toxic algal species of primary concern are the dinoflagellate Alexandrium catenella and members of the pennate diatom genus Pseudo-nitzschia, both producers of potent neurotoxins that are capable of sickening and killing marine life and humans. During the summer of 2004 in Monterey Bay, we observed a change in the taxonomic structure of the phytoplankton community-the typically diatom-dominated community shifted to a red tide, dinoflagellate-dominated community. Here we use a 6-year time series (2000-2006) to show how the abundance of the dominant harmful algal bloom (HAB) species in the Bay up to that point, Pseudo-nitzschia, significantly declined during the dinoflagellate-dominated interval, while two genera of toxic dinoflagellates, Alexandrium and Dinophysis, became the predominant toxin producers. This change represents a shift from a genus of toxin producers that typically dominates the community during a toxic bloom, to HAB taxa that are generally only minor components of the community in a toxic event. This change in the local HAB species was also reflected in the toxins present in higher trophic levels. Despite the small contribution of A. catenella to the overall phytoplankton community, the increase in the presence of this species in Monterey Bay was associated with an increase in the presence of paralytic shellfish poisoning (PSP) toxins in sentinel shellfish and clupeoid fish. This report provides the first evidence that PSP toxins are present in California's pelagic food web, as PSP toxins were detected in both northern anchovies (Engraulis mordax) and Pacific sardines (Sardinops sagax). Another interesting observation from our data is the co-occurrence of DA and PSP toxins in both planktivorous fish and sentinel shellfish. We also provide evidence, based on the statewide biotoxin monitoring program, that this increase in the frequency and abundance of PSP events related to A. catenella occurred not just in Monterey Bay, but also

  2. Population dynamics of toxic phytoplankton and bacterial flora in the waters of the low Adriatic sea; Dinamica di popolazione di fitoplancton tossico e flora batterica nel basso Adriatico

    Energy Technology Data Exchange (ETDEWEB)

    Caroppo, C.; Stabili, L.; Cavallo, R.A.; Pastore, M. [CNR, Ist. Sperimentale Talassografico Attlio Cerruti, Taranto (Italy); Marchiori, E. [Rome Univ., Rome (Italy). Dipt. di Chimica Organica; Bruno, M. [Istituto Superiore di Sanita' , Laboratorio di Igiene Ambientale, Rome (Italy)

    2000-07-01

    The coastal areas of the Southern Adriatic Sea, in particular the Apulian ones, may be considered an example of intact ecosystem and represent an ideal term of comparison to other marine ecosystems having higher levels of pollution (Northern Adriatic Sea). In order to evaluate the sanitary levels of this environment, four transect were investigated during two years monitoring (April 1995-March 1997) along the Otranto Channel coasts, by joint research groups of the Environmental Hygiene Laboratory of the Istituto Superiore di Sanita' and the Istituto Sperimentale Talassografico A. Cerruti of CNR in Taranto. The study underlines the phytoplanktic and bacterial population dynamics, and the detection of the microbiological water quality along the coast tract Brindisi-Lecce-Otranto-S. Maria di Leuca. The results acquired pointed out population dynamics of some potantially toxic species of Dinophysis genus and Pseudo-nitzschia delicatissima. These depended on the winter nutrient loads due to the ASW (Adriatic Superficial Waters) and to the LIW (Levantine Intermediate Waters). The bacterial community was mainly constituted by genera Aeromonas, Photobacterium, Cytophaga and Pseudomonas. Also the presence of Enterobacteriaceae family was relevant. Among the pathogenic vibrios the most frequently isolated species were Vibrio alginolyticus and Vibrio vulnificus. [Italian] Considerando che le zone del basso Adriatico, in particolare quelle pugliesi, costituiscono un biotopo ancora relativamente inalterato, esse sono state oggetto di un'indagine sperimentale condotta in 24 mesi di attivita' (aprile 1995-marzo 1997) lungo le coste del Canale di Otranto, ad opera di un gruppo congiunto del Laboratorio di Igiene Ambientale dell'Istituto Superiore di Sanita' e dei laboratori dell'Istituto Sperimentale Talassografico A. Cerruti del CNR di Taranto, ai fini di valutare lo stato di salute di questo ambiente, che fornisce, con buona probabilita', un

  3. 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

  4. Effect of diatom morphology on the small-scale behavior of the copepod Temora stylifera (Dana, 1849)

    KAUST Repository

    Mahadik, Gauri A.

    2017-05-12

    We explored the small-scale behavior of the calanoid copepod Temora stylifera in relation to the diatoms Chaetoceros socialis, Leptocylindrus aporus, Leptocylindrus danicus and Pseudo-nitzschia calliantha offered as monospecific diets at similar carbon concentrations. These four diatoms are characterized by distinct size, shape and colony forming ability and are important components of the autumnal bloom co-occurring with the seasonal peak of T. stylifera abundance in Mediterranean coastal waters. High-speed video recordings showed that T. stylifera acquired cells in a suspension feeding mode while creating feeding currents. Copepod behavior was quantified in terms of feeding, motion, and grooming activities. T. stylifera spent more time in hovering than cruising in presence of all diets. The solitary L. aporus and P. calliantha elicited longer feeding bouts, lower appendage beat frequency and shorter grooming events compared to the colonial L. danicus and C. socialis. Overall the present results indicate that the behavioral responses of T. stylifera to different diatom diets were species-specific. The observed behavioral plasticity may help T. stylifera to adjust rapidly to changes in the food environment and this can be advantageous in exploiting short-lived phytoplankton blooms.

  5. Molecular Detection of a Potentially Toxic Diatom Species

    Directory of Open Access Journals (Sweden)

    Bidhan Chandra Dhar

    2015-05-01

    Full Text Available A few diatom species produce toxins that affect human and animal health. Among these, members of the Pseudo-nitzschia genus were the first diatoms unambiguously identified as producer of domoic acid, a neurotoxin affecting molluscan shell-fish, birds, marine mammals, and humans. Evidence exists indicating the involvement of another diatom genus, Amphora, as a potential producer of domoic acid. We present a strategy for the detection of the diatom species Amphora coffeaeformis based on the development of species-specific oligonucleotide probes and their application in microarray hybridization experiments. This approach is based on the use of two marker genes highly conserved in all diatoms, but endowed with sufficient genetic divergence to discriminate diatoms at the species level. A region of approximately 450 bp of these previously unexplored marker genes, coding for elongation factor 1-a (eEF1-a and silicic acid transporter (SIT, was used to design oligonucleotide probes that were tested for specificity in combination with the corresponding fluorescently labeled DNA targets. The results presented in this work suggest a possible use of this DNA chip technology for the selective detection of A. coffeaeformis in environmental settings where the presence of this potential toxin producer may represent a threat to human and animal health. In addition, the same basic approach can be adapted to a wider range of diatoms for the simultaneous detection of microorganisms used as biomarkers of different water quality levels.

  6. Actin, actin-related proteins and profilin in diatoms: a comparative genomic analysis.

    Science.gov (United States)

    Aumeier, Charlotte; Polinski, Ellen; Menzel, Diedrik

    2015-10-01

    Diatoms are heterokont unicellular algae with a widespread distribution throughout all aquatic habitats. Research on diatoms has advanced significantly over the last decade due to available genetic transformation methods and publicly available genome databases. Yet up to now, proteins involved in the regulation of the cytoskeleton in diatoms are largely unknown. Consequently, this work focuses on actin and actin-related proteins (ARPs) encoded in the diatom genomes of Thalassiosira pseudonana, Thalassiosira oceanica, Phaeodactylum tricornutum, Fragilariopsis cylindrus and Pseudo-nitzschia multiseries. Our comparative genomic study revealed that most diatoms possess only a single conventional actin and a small set of ARPs. Among these are the highly conserved cytoplasmic Arp1 protein and the nuclear Arp4 as well as Arp6. Diatom genomes contain genes coding for two structurally different homologues of Arp4 that might serve specific functions. All diatom species examined here lack ARP2 and ARP3 proteins, suggesting that diatoms are not capable of forming the Arp2/3 complex, which is essential in most eukaryotes for actin filament branching and plus-end dynamics. Interestingly, none of the sequenced representatives of the Bacillariophyta phylum code for profilin. Profilin is an essential actin-binding protein regulating the monomer actin pool and is involved in filament plus-end dynamics. This is the first report of organisms not containing profilin. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Identification of Phytoplankton Blooms under the Index of Inherent Optical Properties (IOP Index in Optically Complex Waters

    Directory of Open Access Journals (Sweden)

    Jesús A. Aguilar-Maldonado

    2018-01-01

    Full Text Available Phytoplankton blooms are sporadic events in time and are isolated in space. This complex phenomenon is produced by a variety of both natural and anthropogenic causes. Early detection of this phenomenon, as well as the classification of a water body under conditions of bloom or non-bloom, remains an unresolved problem. This research proposes the use of Inherent Optical Properties (IOPs in optically complex waters to detect the bloom or non-bloom state of the phytoplankton community. An IOP index is calculated from the absorption coefficients of the colored dissolved organic matter (CDOM, the phytoplankton (phy and the detritus (d, using the wavelength (λ 443 nm. The effectiveness of this index is tested in five bloom events in different places and with different characteristics from Mexican seas: 1. Dzilam (Caribbean Sea, Atlantic Ocean, a diatom bloom (Rhizosolenia hebetata; 2. Holbox (Caribbean Sea, Atlantic Ocean, a mixed bloom of dinoflagellates (Scrippsiella sp. and diatoms (Chaetoceros sp.; 3. Campeche Bay in the Gulf of Mexico (Atlantic Ocean, a bloom of dinoflagellates (Karenia brevis; 4. Upper Gulf of California (UGC (Pacific Ocean, a diatom bloom (Coscinodiscus and Pseudo-nitzschia and 5. Todos Santos Bay, Ensenada (Pacific Ocean, a dinoflagellate bloom (Lingulodinium polyedrum. The diversity of sites show that the IOP index is a suitable method to determine the phytoplankton bloom conditions.

  8. Autochthonous Optical Signals in CDOM from Phytoplankton Culture and Open Ocean Observations

    Science.gov (United States)

    Kinsey, J. D.; Schnetzer, A.; Bianchi, T. S.; Ziervogel, K.; Lampe, R. H.; Osburn, C. L.

    2016-02-01

    Chromophoric dissolved organic matter (CDOM) is ubiquitous in the marine environment, however information regarding the origin and optical and chemical signals of open ocean autochthonous CDOM is limited. A potential source of CDOM is from phytoplankton-derived particulate organic matter (POM) transformed through microbial degradation and disaggregation. Changes in planktonic base-extracted POM (BEPOM) absorbance and fluorescence signals were tracked through growth and aggregate formation for a cultured diatom (Pseudo-nitzschia spp.). Laboratory observations were combined with open-ocean CDOM and BEPOM optical measurements from two cruises in the Mid-Atlantic Bight, in addition to bacterial production, organic carbon concentrations, and stable carbon isotope values. A five-component parallel factor analysis (PARAFAC) model from coastal BEPOM samples was applied to our samples to identify components within our samples. Preliminary results of BEPOM excitation-emission matrices (EEMs) for both culture and field data exhibited a "three peak" pattern likely representing the aromatic amino acid, tryptophan, and quinone-like fluorescence, suggesting intramolecular charge transfer between electron donors and acceptors—perhaps mediated by aggregate formation. Mid-Atlantic Bight CDOM EEMs were dominated by an excitation peak at ca. 260 nm consistent with tyrosine fluorescence, indicating the ephemeral nature of the BEPOM signal. Further culture and field studies will provide additional insights into the cycling and sources of organic matter in open ocean environments.

  9. Nutrient and Phytoplankton Dynamics along the Ocean Road Sewage Discharge Channel, Dar es Salaam, Tanzania

    Directory of Open Access Journals (Sweden)

    Mariam I. Hamisi

    2014-01-01

    Full Text Available Ocean Road shoreline is situated close to Dar es Salaam largest fish market and is subjected to sewage discharge. In this study, temporal and spatial variations of physicochemical parameters and phytoplankton were studied in five stations along the Ocean Road Coast. Phytoplankton composition, temperature, dissolved oxygen (DO, salinity, water clarity, pH, and dissolved inorganic nutrients (DIN including nitrite, nitrate, and phosphate were measured. Results revealed that DIN were significantly higher in the station close to the discharge point than other stations (P<0.0001. There were no significant temporal variations in DIN except nitrate that was significantly higher during Northeast Monsoon than Southeast Monsoon (P<0.001. Other environmental parameters showed no significant differences except clarity, conductivity, and DO. Occurrence of potential harmful species such as Trichodesmium, Microcystis, and Pseudo-nitzschia was observed. The phytoplankton biomass (chlorophyll a ranged from 3.2 to 56.5 mg m−3 and 18 to 113 mg m−3 for Mjimwema (MJ and Ocean Road (OR stations, respectively. There was significant difference (P=0.0033 in chlorophyll a among the stations being higher in OR II. The phytoplankton biomass was positively correlated with nutrient concentration in all stations except OR I. This study suggests an alarming level of DIN at OR that may alter phytoplankton biomass, abundance, and composition.

  10. Atmospheric aerosol deposition influences marine microbial communities in oligotrophic surface waters of the western Pacific Ocean

    Science.gov (United States)

    Maki, Teruya; Ishikawa, Akira; Mastunaga, Tomoki; Pointing, Stephen B.; Saito, Yuuki; Kasai, Tomoaki; Watanabe, Koichi; Aoki, Kazuma; Horiuchi, Amane; Lee, Kevin C.; Hasegawa, Hiroshi; Iwasaka, Yasunobu

    2016-12-01

    Atmospheric aerosols contain particulates that are deposited to oceanic surface waters. These can represent a major source of nutrients, trace metals, and organic compounds for the marine environment. The Japan Sea and the western Pacific Ocean are particularly affected by aerosols due to the transport of desert dust and industrially derived particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) from continental Asia. We hypothesized that supplementing seawater with aerosol particulates would lead to measurable changes in surface water nutrient composition as well as shifts in the marine microbial community. Shipboard experiments in the Pacific Ocean involved the recovery of oligotrophic oceanic surface water and subsequent supplementation with aerosol particulates obtained from the nearby coastal mountains, to simulate marine particulate input in this region. Initial increases in nitrates due to the addition of aerosol particulates were followed by a decrease correlated with the increase in phytoplankton biomass, which was composed largely of Bacillariophyta (diatoms), including Pseudo-nitzschia and Chaetoceros species. This shift was accompanied by changes in the bacterial community, with apparent increases in the relative abundance of heterotrophic Rhodobacteraceae and Colwelliaceae in aerosol particulate treated seawater. Our findings provide empirical evidence revealing the impact of aerosol particulates on oceanic surface water microbiology by alleviating nitrogen limitation in the organisms.

  11. In vivo genotoxicity testing of the amnesic shellfish poison (domoic acid) in piscine erythrocytes using the micronucleus test and the comet assay

    Energy Technology Data Exchange (ETDEWEB)

    Cavas, Tolga [Mersin University, Faculty of Sciences and Letters, Department of Biology, 33343 Mersin (Turkey)], E-mail: tcavas@mersin.edu.tr; Koenen, Serpil [Mersin University, Faculty of Sciences and Letters, Department of Biology, 33343 Mersin (Turkey)

    2008-11-11

    Domoic acid (DA) is a neurotoxic amino acid naturally produced in the marine environment by some diatom species belonging to the genus Pseudo-nitzschia. Although the neurotoxic properties of DA have been demonstrated, very little is known about in vivo genotoxicity of DA on aquatic organisms. In the present paper, an in vivo study on the genotoxic effects of domoic acid was carried out on a fish, Oreochromis niloticus, using the micronucleus test and the comet assay. The fish were exposed to three doses of domoic acid (1, 5 and 10 {mu}g/g body weight) by intracoelomic injections. Ethyl methane sulphonate at a single dose of 5 mg/l was used as positive control. Analysis of micronuclei, nuclear abnormalities and DNA damage were carried out on peripheral erythrocytes sampled 24, 48 and 72 h post-treatment. Our results revealed significant increases in the frequencies of micronuclei, nuclear abnormalities as well as DNA strand breaks and thus demonstrated the genotoxic potential of DA on fish.

  12. Domoic Acid - A New Toxin in the Croatian Adriatic Shellfish Toxin Profile

    Directory of Open Access Journals (Sweden)

    Ivona Marasović

    2010-10-01

    Full Text Available This is the first study that presents concentrations of domoic acid detected in the whole shellfish tissue from breeding and harvesting areas along the Croatian coast of the Adriatic Sea during the period 2006 to 2008. Shellfish sample analyses after SAX cleaning procedures, using a UV-DAD-HPLC system, showed the presence of domoic acid in four species. The most prevalent of those species were the blue mussel (Mytilus galloprovincialis, followed by European flat oyster (Ostrea edulis, Mediterranean scallop (Pecten jacobaeus and proteus scallop (Flexopecten proteus. Domoic acid, a potentially lethal phycotoxin that causes amnesic shellfish poisoning (ASP, was detected for the first time in January 2006 with the highest value of 6.5486 μg g-1 in whole shellfish tissue. Pseudo-nitzschia spp. bloom events preceded these high domoic acid concentrations. According to this study, retention of domoic acid in the blue mussel M. galloprovincialis is more than 42 days. This investigation indicates the first presence of domoic acid in Croatian shellfish, but in concentrations under the regulatory limit (20 μg g-1, therefore shellfish consumption was not found to endanger human health.

  13. Mechanism of ferrous iron binding and oxidation by ferritin from a pennate diatom.

    Science.gov (United States)

    Pfaffen, Stephanie; Abdulqadir, Raz; Le Brun, Nick E; Murphy, Michael E P

    2013-05-24

    A novel ferritin was recently found in Pseudo-nitzschia multiseries (PmFTN), a marine pennate diatom that plays a major role in global primary production and carbon sequestration into the deep ocean. Crystals of recombinant PmFTN were soaked in iron and zinc solutions, and the structures were solved to 1.65-2.2-Å resolution. Three distinct iron binding sites were identified as determined from anomalous dispersion data from aerobically grown ferrous soaked crystals. Sites A and B comprise the conserved ferroxidase active site, and site C forms a pathway leading toward the central cavity where iron storage occurs. In contrast, crystal structures derived from anaerobically grown and ferrous soaked crystals revealed only one ferrous iron in the active site occupying site A. In the presence of dioxygen, zinc is observed bound to all three sites. Iron oxidation experiments using stopped-flow absorbance spectroscopy revealed an extremely rapid phase corresponding to Fe(II) oxidation at the ferroxidase site, which is saturated after adding 48 ferrous iron to apo-PmFTN (two ferrous iron per subunit), and a much slower phase due to iron core formation. These results suggest an ordered stepwise binding of ferrous iron and dioxygen to the ferroxidase site in preparation for catalysis and a partial mobilization of iron from the site following oxidation.

  14. Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom*

    Science.gov (United States)

    Pfaffen, Stephanie; Abdulqadir, Raz; Le Brun, Nick E.; Murphy, Michael E. P.

    2013-01-01

    A novel ferritin was recently found in Pseudo-nitzschia multiseries (PmFTN), a marine pennate diatom that plays a major role in global primary production and carbon sequestration into the deep ocean. Crystals of recombinant PmFTN were soaked in iron and zinc solutions, and the structures were solved to 1.65–2.2-Å resolution. Three distinct iron binding sites were identified as determined from anomalous dispersion data from aerobically grown ferrous soaked crystals. Sites A and B comprise the conserved ferroxidase active site, and site C forms a pathway leading toward the central cavity where iron storage occurs. In contrast, crystal structures derived from anaerobically grown and ferrous soaked crystals revealed only one ferrous iron in the active site occupying site A. In the presence of dioxygen, zinc is observed bound to all three sites. Iron oxidation experiments using stopped-flow absorbance spectroscopy revealed an extremely rapid phase corresponding to Fe(II) oxidation at the ferroxidase site, which is saturated after adding 48 ferrous iron to apo-PmFTN (two ferrous iron per subunit), and a much slower phase due to iron core formation. These results suggest an ordered stepwise binding of ferrous iron and dioxygen to the ferroxidase site in preparation for catalysis and a partial mobilization of iron from the site following oxidation. PMID:23548912

  15. A Diatom Ferritin Optimized for Iron Oxidation but Not Iron Storage.

    Science.gov (United States)

    Pfaffen, Stephanie; Bradley, Justin M; Abdulqadir, Raz; Firme, Marlo R; Moore, Geoffrey R; Le Brun, Nick E; Murphy, Michael E P

    2015-11-20

    Ferritin from the marine pennate diatom Pseudo-nitzschia multiseries (PmFTN) plays a key role in sustaining growth in iron-limited ocean environments. The di-iron catalytic ferroxidase center of PmFTN (sites A and B) has a nearby third iron site (site C) in an arrangement typically observed in prokaryotic ferritins. Here we demonstrate that Glu-44, a site C ligand, and Glu-130, a residue that bridges iron bound at sites B and C, limit the rate of post-oxidation reorganization of iron coordination and the rate at which Fe(3+) exits the ferroxidase center for storage within the mineral core. The latter, in particular, severely limits the overall rate of iron mineralization. Thus, the diatom ferritin is optimized for initial Fe(2+) oxidation but not for mineralization, pointing to a role for this protein in buffering iron availability and facilitating iron-sparing rather than only long-term iron storage. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Domoic Acid Toxicologic Pathology: A Review

    Directory of Open Access Journals (Sweden)

    Olga M. Pulido

    2008-05-01

    Full Text Available Domoic acid was identified as the toxin responsible for an outbreak of human poisoning that occurred in Canada in 1987 following consumption of contaminated blue mussels [Mytilus edulis]. The poisoning was characterized by a constellation of clinical symptoms and signs. Among the most prominent features described was memory impairment which led to the name Amnesic Shellfish Poisoning [ASP]. Domoic acid is produced by certain marine organisms, such as the red alga Chondria armata and planktonic diatom of the genus Pseudo-nitzschia. Since 1987, monitoring programs have been successful in preventing other human incidents of ASP. However, there are documented cases of domoic acid intoxication in wild animals and outbreaks of coastal water contamination in many regions world-wide. Hence domoic acid continues to pose a global risk to the health and safety of humans and wildlife. Several mechanisms have been implicated as mediators for the effects of domoic acid. Of particular importance is the role played by glutamate receptors as mediators of excitatory neurotransmission and the demonstration of a wide distribution of these receptors outside the central nervous system, prompting the attention to other tissues as potential target sites. The aim of this document is to provide a comprehensive review of ASP, DOM induced pathology including ultrastructural changes associated to subchronic oral exposure, and discussion of key proposed mechanisms of cell/tissue injury involved in DOM induced brain pathology and considerations relevant to food safety and human health.

  17. Seasonal phytoplankton dynamics in extreme southern South America (Beagle Channel, Argentina)

    Science.gov (United States)

    Almandoz, Gastón O.; Hernando, Marcelo P.; Ferreyra, Gustavo A.; Schloss, Irene R.; Ferrario, Martha E.

    2011-08-01

    The phytoplankton biomass and composition dynamics in relation with environmental factors were explored during an annual cycle (July 2006-2007) for the first time in the Beagle Channel. Samples were examined by light and scanning electron microscopy and carbon biomass was estimated using measured cell biovolumes. The annual cycle was characterized by a sharp contrast between low density and biomass during the autumn-winter period and a significant increase during spring and summer. The maximum biomass peak was observed during early spring (141 μg C l - 1 and 8.7 μg Chl a l - 1 ) and was associated with a bloom of the diatom genus Chaetoceros. In spite of a strong nutrient depletion that lead to the subsequent bloom decline, a second peak of biomass was observed after 2 weeks, mainly represented by the diatoms T. mendiolana and T. anguste-lineata. Towards the end of spring and during summer diatom density decreased and assemblages were enriched by unidentified tiny phytoflagellates and dinoflagellates. A total of 138 taxa were identified during the study period. From these, 10 are known as potentially toxic species: Alexandrium catenella, A. ostenfeldii, A. tamarense, Dinophysis acuminata, D. rotundata, Prorocentrum cordatum, Pseudo-nitzschia australis, P. calliantha, P. fraudulenta and P. cf. seriata. Their presence is noteworthy since the area sustains a growing aquiculture production.

  18. Modulatory effects of Terminalia arjuna against domoic acid induced toxicity in Caco-2 cell line.

    Science.gov (United States)

    Ramya, E M; Kumar, G Phani; Anand, T; Anilakumar, K R

    2017-08-01

    Domoic acid is a potent marine algal toxin produced by diatomic genus of Pseudo-nitzschia causing amnesic shell fish poisoning. Domoic acid toxicosis mainly involves excitotoxic effects coupled with oxidative stress. The present study was aimed to evaluate the protective effects of hydro-alcoholic extract of Terminalia arjuna (TA) against domoic acid induced toxic effects in Caco-2 cell line. It was observed that the toxicity induced by domoic acid in Caco-2 cells was mediated by oxidative insult leading to morphological changes, DNA damage and apoptosis. In our study pre-treatment of the cells with TA (10, 20 and 30 μg/ml) showed significant protection against domoic acid induced morphological, oxidative and apoptotic damages in a dose dependent manner. The effect of phytocompounds present in TA viz., kaempferol and arjungenin showed significant protection against domoic acid induced toxicity in Caco-2 cell line. Hence, it could be inferred that the protective effect of TA extract against domoic acid induced toxicity could be due to the individual or synergistic effects of kaempferol and argungenin. However, further clinical studies are warranted to consider TA as a natural remedy to prevent amnesic shell fish poisoning.

  19. What California sea lions exposed to domoic acid might teach us about autism: lessons for predictive and preventive medicine.

    Science.gov (United States)

    Lahvis, Garet Paul

    2017-09-01

    Autism spectrum disorder (ASD) shares many biological and behavioral similarities with the deleterious effects of domoic acid (DA) exposure. DA is produced by marine algae and most commonly by species of Pseudo-nitzschia. Humans and marine mammals can be exposed to DA when they consume whole fish or shellfish. The mammalian fetus is highly sensitive to the deleterious effects of DA exposure. Both ASD and exposures to toxic levels of DA feature repetitive behaviors, challenges with social interaction, and seizures. They can also share a commonality in brain anatomy and function, particularly the balance between excitatory and inhibitory mechanisms. The current article is relevant to predictive, preventive, and personalized medicine for three reasons. First, shellfish consumption may be a risk factor for ASD and the regulatory limit for DA should be adjusted to prevent this possibility. Human contributions to increased algal production of DA in coastal waters should be identified and reduced. Second, evaluations of sentinel species wild and free-roaming in the environment, though typically outside the purview of biomedical research, should be much more fully employed to gain insights to risk factors for human disease. To better identify and prevent disease, biomedical researchers should study wild populations. Third, studies of DA exposure highlight the possibility that glutamate additives to processed foods may also have deleterious impacts on human brain development and behavior.

  20. Occurrence of Harmful Algal Species and Shellfish Toxicity in Sardinia (Italy).

    Science.gov (United States)

    Bazzoni, Anna Maria; Mudadu, Alessandro Graziano; Lorenzoni, Giuseppa; Arras, Igor; Lugliè, Antonella; Vivaldi, Barbara; Cicotelli, Valentina; Sanna, Giovanna; Tedde, Giuseppe; Ledda, Salvatore; Alesso, Enrico; Marongiu, Edoardo; Virgilio, Sebastiano

    2016-09-20

    Sardinia (Italy, north-western Mediterranean) is a commercially important producer of edible bivalve molluscs. Since the early 2000s, it was subjected to recurring cases of mussel farm closures due to toxic algal poison. Here, we present the studies on toxin concentrations and the associated potentially toxic phytoplankton distribution and abundances carried out by a regular monitoring programme in Sardinian shellfish areas, from January to May 2015. Diarrheic shellfish poisoning (DSP) toxins were detected in several bivalve molluscs samples, while paralytic shellfish poisoning (PSP) and paralytic shellfish poisoning toxins were present just once, without exceeding the legal limits. Potentially toxic algal species have been constantly present. Pseudo-nitzschia species were present during the entire study often with high abundances, while Dinophysis species reached high densities sporadically. Among PSP phytoplankton, only Alexandrium minutum Halim was found. The data obtained in this study showed an increase in the DSP toxicity in mussels in Sardinia. No clear relation between the occurrence of toxins in shellfish and the presence of potentially toxic algal species was found, although a slight correlation between DSP toxins and Dinophysis species could be supported.

  1. Occurrence of harmful algal species and shellfish toxicity in Sardinia (Italy

    Directory of Open Access Journals (Sweden)

    Anna Maria Bazzoni

    2016-11-01

    Full Text Available Sardinia (Italy, north-western Mediterranean is a commercially important producer of edible bivalve molluscs. Since the early 2000s, it was subjected to recurring cases of mussel farm closures due to toxic algal poison. Here, we present the studies on toxin concentrations and the associated potentially toxic phytoplankton distribution and abundances carried out by a regular monitoring programme in Sardinian shellfish areas, from January to May 2015. Diarrheic shellfish poisoning (DSP toxins were detected in several bivalve molluscs samples, while paralytic shellfish poisoning (PSP and paralytic shellfish poisoning toxins were present just once, without exceeding the legal limits. Potentially toxic algal species have been constantly present. Pseudo-nitzschia species were present during the entire study often with high abundances, while Dinophysis species reached high densities sporadically. Among PSP phytoplankton, only Alexandrium minutum Halim was found. The data obtained in this study showed an increase in the DSP toxicity in mussels in Sardinia. No clear relation between the occurrence of toxins in shellfish and the presence of potentially toxic algal species was found, although a slight correlation between DSP toxins and Dinophysis species could be supported.

  2. Development of coastal upwelling edge detection algorithms associated with harmful algal blooms off the Washington coast using sea surface temperature imagery.

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Nathan R.; Woodruff, Dana L.; Trainer, Vera L.

    2005-01-01

    Satellite remote sensing imagery is being used to identify and characterize upwelling conditions on the coast of Washington State, with an emphasis on detecting ocean features associated with harmful algal bloom events. Blooms of phytoplankton, including the domoic acid-producing diatom Pseudo-nitzschia, appear to be associated with a semi-permanent eddy bordering Washington and British Columbia that is observed in satellite imagery during extended upwelling events. Strong upwelling conditions may act as a barrier to movement of these blooms onshore. Using NOAA AVHRR temperature imagery, edge detection algorithms are being developed to define the strength, location and extent of the surface temperature expression of upwelling along the coast of Washington. The edge detection technique uses a simple kernel-based gradient method that compares temperatures of pixels at a user-specified distance. This allows identification of larger features with subtle edges. The resulting maximum-gradient map is then converted to a binary format with a user-specified temperature threshold. Skeletonization and edge-linking algorithms are then employed to develop final map products. The upwelling edge detection maps are being examined in relation to harmful algal bloom events that have occurred along the coast.

  3. Food and feeding behaviour of Mozambique tilapia (Oreochromis mossambicus Peters from Borna Reservoir of Maharashtra, India

    Directory of Open Access Journals (Sweden)

    Vishwas balasaheb Sakhare

    2016-12-01

    Full Text Available The food analysis of 80 specimens of Oreochromis mossambicus collected from Borna Reservoir of Maharashtra, India revealed that the food of juveniles mainly consisted of rotifers (35%, followed by copepods (30%, Chlorophyceae (20%, Bacillariophyceae (10% and aquatic insects (5%. While the food items recorded in the gut of adults were Chlorophyceae (40%, followed by Bacillariophyceae (30%, rotifers (15%, copepods (10% and aquatic insects (5%. During present study it was found that the juveniles of O. mossamobicus mainly feed on zooplankton, and adults on phytoplankton. Intense feeding was noticed during summer season and juveniles were the active feeders.

  4. Harmful algae and toxis in paranaguá bay , Brazil: bases for monitoring

    Directory of Open Access Journals (Sweden)

    Luiz Laureno Mafra Junior

    2006-09-01

    Full Text Available The estuarine complex of Paranaguá - ECP (South Brazil, 25º30'S, 48º30'W is a large subtropical system, where pristine mangrove forests are still present, and fishery and aquaculture are important economic activities. This work investigated the occurrence of harmful algae in Paranaguá Bay, as well as the presence of toxins in the filter feeding mussel Mytella guyanensis, a local fishery resource. Samples along the Paranaguá sub-system were collected almost monthly from August 2002 to October 2003. Besides physical and chemical variables, cell densities of harmful species and presence of toxins in the mussel by mouse bioassay (DSP, PSP and HPLC (ASP were performed. HAB species included Pseudo-nitzschia spp., Dinophysis acuminata,Prorocentrum minimum,Gymnodinium catenatum,Phaeocystis spp., Chattonella spp. and Heterosigma akashiwo.Trichodesmium erythraeum and Coscinodiscus wailesii were also included in this study due to their potential for harmful bloom formation. Toxin results showed the occurrence of DSP (December 2002 in shellfish related to the presence of D. acuminata (max. 4,566 cells.l-1. Additionally, cultivated strains produced paralytic and amnesic toxins in laboratory. Spring (October to December, Southern Hemisphere and late summer (February to April were the periods of higher abundance of harmful algae, mainly in euhaline and inner polyhaline sectors of the ECP.O complexo estuarino de Paranaguá (CEP; 25º30'S, 48º30'W, localizado no litoral sul do Brasil, abriga extensas áreas preservadas de manguezais e tem a pesca e aqüicultura como importantes atividades econômicas. Este trabalho investigou a ocorrência de microalgas nocivas no CEP e a presença de ficotoxinas no molusco bivalve Mytella guyanensis. Para tanto, foram coletadas amostras com periodicidade aproximadamente mensal, entre agosto de 2002 e outubro de 2003. Foram avaliadas variáveis físico-químicas, densidade de espécies nocivas e a presença de toxinas nos

  5. Initial skill assessment of the California Harmful Algae Risk Mapping (C-HARM) system.

    Science.gov (United States)

    Anderson, Clarissa R; Kudela, Raphael M; Kahru, Mati; Chao, Yi; Rosenfeld, Leslie K; Bahr, Frederick L; Anderson, David M; Norris, Tenaya A

    2016-11-01

    Toxic algal events are an annual burden on aquaculture and coastal ecosystems of California. The threat of domoic acid (DA) toxicity to human and wildlife health is the dominant harmful algal bloom (HAB) concern for the region, leading to a strong focus on prediction and mitigation of these blooms and their toxic effects. This paper describes the initial development of the California Harmful Algae Risk Mapping (C-HARM) system that predicts the spatial likelihood of blooms and dangerous levels of DA using a unique blend of numerical models, ecological forecast models of the target group, Pseudo-nitzschia, and satellite ocean color imagery. Data interpolating empirical orthogonal functions (DINEOF) are applied to ocean color imagery to fill in missing data and then used in a multivariate mode with other modeled variables to forecast biogeochemical parameters. Daily predictions (nowcast and forecast maps) are run routinely at the Central and Northern California Ocean Observing System (CeNCOOS) and posted on its public website. Skill assessment of model output for the nowcast data is restricted to nearshore pixels that overlap with routine pier monitoring of HABs in California from 2014 to 2015. Model lead times are best correlated with DA measured with solid phase adsorption toxin tracking (SPATT) and marine mammal strandings from DA toxicosis, suggesting long-term benefits of the HAB predictions to decision-making. Over the next three years, the C-HARM application system will be incorporated into the NOAA operational HAB forecasting system and HAB Bulletin. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. The influence of environmental variability on the biogeography of coccolithophores and diatoms in the Great Calcite Belt

    Science.gov (United States)

    Smith, Helen E. K.; Poulton, Alex J.; Garley, Rebecca; Hopkins, Jason; Lubelczyk, Laura C.; Drapeau, Dave T.; Rauschenberg, Sara; Twining, Ben S.; Bates, Nicholas R.; Balch, William M.

    2017-11-01

    The Great Calcite Belt (GCB) of the Southern Ocean is a region of elevated summertime upper ocean calcite concentration derived from coccolithophores, despite the region being known for its diatom predominance. The overlap of two major phytoplankton groups, coccolithophores and diatoms, in the dynamic frontal systems characteristic of this region provides an ideal setting to study environmental influences on the distribution of different species within these taxonomic groups. Samples for phytoplankton enumeration were collected from the upper mixed layer (30 m) during two cruises, the first to the South Atlantic sector (January-February 2011; 60° W-15° E and 36-60° S) and the second in the South Indian sector (February-March 2012; 40-120° E and 36-60° S). The species composition of coccolithophores and diatoms was examined using scanning electron microscopy at 27 stations across the Subtropical, Polar, and Subantarctic fronts. The influence of environmental parameters, such as sea surface temperature (SST), salinity, carbonate chemistry (pH, partial pressure of CO2 (pCO2), alkalinity, dissolved inorganic carbon), macronutrients (nitrate + nitrite, phosphate, silicic acid, ammonia), and mixed layer average irradiance, on species composition across the GCB was assessed statistically. Nanophytoplankton (cells 2-20 µm) were the numerically abundant size group of biomineralizing phytoplankton across the GCB, with the coccolithophore Emiliania huxleyi and diatoms Fragilariopsis nana, F. pseudonana, and Pseudo-nitzschia spp. as the most numerically dominant and widely distributed. A combination of SST, macronutrient concentrations, and pCO2 provided the best statistical descriptors of the biogeographic variability in biomineralizing species composition between stations. Emiliania huxleyi occurred in silicic acid-depleted waters between the Subantarctic Front and the Polar Front, a favorable environment for this species after spring diatom blooms remove silicic acid

  7. [Competition of two marine diatom algae for urea and nitrate nitrogen under three levels of irradiance].

    Science.gov (United States)

    Il'iash, L V; Zapara, E V

    2006-01-01

    Biomass dynamics of the plankton diatoms Thalassiosira weissflogii and Pseudo-nitzschia delicatissima were analyzed in batch mono- and mixed cultures grown on media with urea or nitrate as the sources of nitrogen, under irradiance 13, 38, and 115 microE/(m(2) x s). At the initial enrichment, nitrogen concentration was 0.18 mmol, and the nitrogen : phosphorus ratio was 5 : 1. The mechanisms of competition for the limiting resource satisfactorily described the interactions between the algae grown on urea. Competitive ability of algae was characterised according to the value of competitive eddect (CE), which was calculated as the ratio of growth rate and accumulated biomass decrease in mixed culture to that in monoculture CE of algae grown on urea increased with the increasing of irradiance and was lower than that of algae grown on nitrate. CE of P. delicatissima was higher than that T. weissflogii, independently of the source of nigrogen and the level of irradiance. At 38 and 115 microE/(m(2) x s) the growth of T. weissflogii ceased earlier than that of P. delicatissima, independently of the source o nitrogen. At 13 microE/(m(2) x s) the growth of P. delicatissima ceased earlier than of T. weissflogii in on cultures grown urea, but the growth of T. weissflogii was the first to cease on nitrate. The competition revealed in experimental communities for the nitrogen of urea between plankton algae gives reasons to suggest that in natural communities plankton algae also compere under inorganic nitrogen deficiency and organic nitrogen abundance.

  8. The relationship between phytoplankton distribution and water column characteristics in North West European shelf sea waters.

    Science.gov (United States)

    Fehling, Johanna; Davidson, Keith; Bolch, Christopher J S; Brand, Tim D; Narayanaswamy, Bhavani E

    2012-01-01

    Phytoplankton underpin the marine food web in shelf seas, with some species having properties that are harmful to human health and coastal aquaculture. Pressures such as climate change and anthropogenic nutrient input are hypothesized to influence phytoplankton community composition and distribution. Yet the primary environmental drivers in shelf seas are poorly understood. To begin to address this in North Western European waters, the phytoplankton community composition was assessed in light of measured physical and chemical drivers during the "Ellett Line" cruise of autumn 2001 across the Scottish Continental shelf and into adjacent open Atlantic waters. Spatial variability existed in both phytoplankton and environmental conditions, with clear differences not only between on and off shelf stations but also between different on shelf locations. Temperature/salinity plots demonstrated different water masses existed in the region. In turn, principal component analysis (PCA), of the measured environmental conditions (temperature, salinity, water density and inorganic nutrient concentrations) clearly discriminated between shelf and oceanic stations on the basis of DIN:DSi ratio that was correlated with both salinity and temperature. Discrimination between shelf stations was also related to this ratio, but also the concentration of DIN and DSi. The phytoplankton community was diatom dominated, with multidimensional scaling (MDS) demonstrating spatial variability in its composition. Redundancy analysis (RDA) was used to investigate the link between environment and the phytoplankton community. This demonstrated a significant relationship between community composition and water mass as indexed by salinity (whole community), and both salinity and DIN:DSi (diatoms alone). Diatoms of the Pseudo-nitzschia seriata group occurred at densities potentially harmful to shellfish aquaculture, with the potential for toxicity being elevated by the likelihood of DSi limitation of

  9. The relationship between phytoplankton distribution and water column characteristics in North West European shelf sea waters.

    Directory of Open Access Journals (Sweden)

    Johanna Fehling

    Full Text Available Phytoplankton underpin the marine food web in shelf seas, with some species having properties that are harmful to human health and coastal aquaculture. Pressures such as climate change and anthropogenic nutrient input are hypothesized to influence phytoplankton community composition and distribution. Yet the primary environmental drivers in shelf seas are poorly understood. To begin to address this in North Western European waters, the phytoplankton community composition was assessed in light of measured physical and chemical drivers during the "Ellett Line" cruise of autumn 2001 across the Scottish Continental shelf and into adjacent open Atlantic waters. Spatial variability existed in both phytoplankton and environmental conditions, with clear differences not only between on and off shelf stations but also between different on shelf locations. Temperature/salinity plots demonstrated different water masses existed in the region. In turn, principal component analysis (PCA, of the measured environmental conditions (temperature, salinity, water density and inorganic nutrient concentrations clearly discriminated between shelf and oceanic stations on the basis of DIN:DSi ratio that was correlated with both salinity and temperature. Discrimination between shelf stations was also related to this ratio, but also the concentration of DIN and DSi. The phytoplankton community was diatom dominated, with multidimensional scaling (MDS demonstrating spatial variability in its composition. Redundancy analysis (RDA was used to investigate the link between environment and the phytoplankton community. This demonstrated a significant relationship between community composition and water mass as indexed by salinity (whole community, and both salinity and DIN:DSi (diatoms alone. Diatoms of the Pseudo-nitzschia seriata group occurred at densities potentially harmful to shellfish aquaculture, with the potential for toxicity being elevated by the likelihood of DSi

  10. Microarray testing for the presence of toxic algae monitoring programme in Galicia (NW Spain).

    Science.gov (United States)

    Dittami, Simon M; Pazos, Yolanda; Laspra, Melchor; Medlin, Linda K

    2013-10-01

    Rapid and reliable detection of harmful algae in coastal areas and shellfish farms is an important requirement of monitoring programmes. Monitoring of toxic algae by means of traditional methods, i.e., light microscopy, can be time consuming when many samples have to be routinely analysed. Reliable species identification requires expensive equipment and trained personnel to carry out the analyses. However, all techniques for the monitoring of harmful algae usually require transportation of samples to specialised laboratories. In many monitoring laboratories, results are usually obtained within five working days after receiving the sample and therefore preventative measures are not always possible. Molecular technologies are rapidly improving the detection of phytoplankton and their toxins and the speed at which the results can be obtained. Assays are based on the discrimination of the genetic differences of the different species and species-specific probes can be designed. Such probes have been adapted to a microarray or phylochip format and assessed in several EU monitoring sites. Microarray results are presented for 1 year of field samples validated with cell counts from concentrated samples taken during toxic events from the weekly sampling of the Galician Monitoring Programme done by INTECMAR. The Galician monitoring laboratory does their own counting and their results are posted on their web site within 24 h. There was good correlation between cells present and microarray signals. In the few cases of false negatives, these can be attributed to poor RNA extraction of the target species, viz. Prorocentrum or Dinophysis. Where potential false positives were encountered, the smaller volume taken for cell counts as compared to the upto 300 times more volume taken for RNA extraction for the microarray is likely the cause for these differences, making the microarray more sensitive. The microarray was able to provide better species resolution in Alexandrium and Pseudo-nitzschia

  11. Simultaneous monitoring of faecal indicators and harmful algae using an in-situ autonomous sensor.

    Science.gov (United States)

    Yamahara, K M; Demir-Hilton, E; Preston, C M; Marin, R; Pargett, D; Roman, B; Jensen, S; Birch, J M; Boehm, A B; Scholin, C A

    2015-08-01

    Faecal indicator bacteria (FIB) and harmful algal blooms (HABs) threaten the health and the economy of coastal communities worldwide. Emerging automated sampling technologies combined with molecular analytical techniques could enable rapid detection of micro-organisms in-situ, thereby improving resource management and public health decision-making. We evaluated this concept using a robotic device, the Environmental Sample Processor (ESP). The ESP automates in-situ sample collection, nucleic acid extraction and molecular analyses. Here, the ESP measured and reported concentrations of FIB (Enterococcus spp.), a microbial source-tracking marker (human-specific Bacteriodales) and a HAB species (Psuedo-nitzschia spp.) over a 45-day deployment on the Santa Cruz Municipal Wharf (Santa Cruz, CA, USA). Both FIB and HABs were enumerated from single in-situ collected water samples. The in-situ qPCR efficiencies ranged from 86% to 105%, while the limit of quantifications during the deployment was 10 copies reaction(-1) . No differences were observed in the concentrations of enterococci, the human-specific marker in Bacteroidales spp., and P. australis between in-situ collected sample and traditional hand sampling methods (P > 0·05). Analytical results were Internet-accessible within hours of sample collection, demonstrating the feasibility of same-day public notification of current water quality conditions. This study presents the first report of in-situ qPCR enumeration of both faecal indicators and harmful algal species in coastal marine waters. We utilize a robotic device for in-situ quantification of enterococci, the human-specific marker in Bacteriodales and Pseudo-nitzschia spp. from the same water samples collected and processed in-situ. The results demonstrate that rapid, in-situ monitoring can be utilized to identify and quantify multiple health-relevant micro-organisms important in water quality monitoring and that this monitoring can be used to inform same

  12. Microplankton composition, production and upwelling dynamics in Sagres (SW Portugal during summer of 2001

    Directory of Open Access Journals (Sweden)

    Sofia Loureiro

    2005-09-01

    Full Text Available Microplankton community, production, and respiration were studied alongside physical and chemical conditions at Sagres (SW Portugal during the upwelling season, from May to September 2001. The sampling station was 5 km east of the upwelling centre off Cabo S. Vicente, and 2 km west of an offshore installation for bivalve aquaculture. Three major periods were distinguished according to sea surface temperature (SST: period 1 (P1; May and June, characterised by high temperature values (17.0±1.8°C; period 2 (P2; July, characterised by lower temperatures (14.6±0.3°C, identified as an upwelling-blooming stage; and period 3 (P3; August, characterised by a high temperature pattern (16.25±1.14°C. Chaetoceros spp., Thalassiosira spp., Lauderia spp., Detonula spp. and Pseudo-nitzschia spp. were the major taxa contributing to the dissimilarities between P2 (July and the other periods. In July (P2, the average gross production (GP; 52.5±12.3 µM O2 d-1 and net community production (NCP; 46.9±15.3 µM O2 d-1 peaked with the maximal concentrations of diatom-chl a. Dark community respiration (DCR remained low and more constant throughout (4.6±3.6 µM O2 d-1. The plankton assemblage was dominated by diatoms throughout the survey. Physical events were the primary factors determining the microplankton structure and distribution at this location.

  13. Phytoplankton Assemblage Patterns in the Southern Mid-Atlantic Bight

    Science.gov (United States)

    Makinen, Carla; Moisan, Tiffany A. (Editor)

    2012-01-01

    As part of the Wallops Coastal Oceans Observing Laboratory (Wa-COOL) Project, we sampled a time-series transect in the southern Mid-Atlantic Bight (MAB) biweekly. Our 2-year time-series data included physical parameters, nutrient concentrations, and chlorophyll a concentrations. A detailed phytoplankton assemblage structure was examined in the second year. During the 2-year study, chlorophyll a concentration (and ocean color satellite imagery) indicated that phytoplankton blooms occurred in January/February during mixing conditions and in early autumn under stratified conditions. The chlorophyll a concentrations ranged from 0.25 microgram 1(exp -1) to 15.49 microgram 1(exp -1) during the 2-year period. We were able to discriminate approximately 116 different species under phase contrast microscopy. Dominant phytoplankton included Skeletonema costatum, Rhizosolenia spp., and Pseudo-nitzschia pungens. In an attempt to determine phytoplankton species competition/succession within the assemblage, we calculated a Shannon Weaver diversity index for our diatom microscopy data. Diatom diversity was greatest during the winter and minimal during the spring. Diatom diversity was also greater at nearshore stations than at offshore stations. Individual genera appeared patchy, with surface and subsurface patches appearing abruptly and persisting for only 1-2 months at a time. The distribution of individual species differed significantly from bulk variables of the assemblage (chlorophyll a ) and total phytoplankton assemblage (cells), which indicates that phytoplankton species may be limited in growth in ways that differ from those of the total assemblage. Our study demonstrated a highly diverse phytoplankton assemblage throughout the year, with opportunistic species dominating during spring and fall in response to seasonal changes in temperature and nutrients in the southern MAB.

  14. Immunomodulatory effects upon in vitro exposure of California sea lion and southern sea otter peripheral blood leukocytes to domoic acid.

    Science.gov (United States)

    Levin, Milton; Joshi, Dhanashree; Draghi, Andrew; Gulland, Frances M; Jessup, David; De Guise, Sylvain

    2010-04-01

    During red tide bloom events, the marine diatom Pseudo-nitzschia produces the toxin domoic acid (DA), which has been associated with stranding and mortality events involving California sea lions (Zalophus californianus) and southern sea otters (Enhydra lutris). In addition to these well-documented DA-induced neurotoxic events, there is increasing concern that DA may exert chronic effects, such as immunomodulation, which may potentially increase an individual's susceptibility to a number of opportunistic infections following nonlethal exposure. We investigated the effects of DA on innate (phagocytosis and respiratory burst) and adaptive (mitogen-induced lymphocyte proliferation) immune functions with the use of peripheral blood leukocytes collected from healthy California sea lions and southern sea otters upon in vitro exposure to 0 (unexposed control), 0.0001, 0.001, 0.01, 0.1, 1.0, 10, and 100 microM DA. Domoic acid did not significantly modulate phagocytosis or respiratory burst in either species. For California sea lions, DA significantly increased ConA-induced T-lymphocyte proliferation upon exposure to DA concentrations ranging from 0.0001 to 10 microM, resulting in a nonlinear dose-response curve. There was no effect on lymphocyte proliferation at the highest concentration of DA tested. No effects on lymphocyte proliferation were observed in southern sea otters. Importantly, the in vitro DA concentrations affecting T-cell proliferation were within or below the range of DA in serum measured in free-ranging California sea lions following natural exposure, suggesting a risk for immunomodulation in free-ranging animals. Understanding the risk for immunomodulation upon DA exposure will contribute in the health assessment and management of California sea lions and southern sea otters, as well as guide veterinarians and wildlife rehabilitators in caring for and treating afflicted animals.

  15. The occurrence of domoic acid linked to a toxic diatom bloom in a new potential vector: the tunicate Pyura chilensis (piure).

    Science.gov (United States)

    López-Rivera, Américo; Pinto, Maricela; Insinilla, Andrea; Suárez Isla, Benjamín; Uribe, Eduardo; Alvarez, Gonzalo; Lehane, Mary; Furey, Ambrose; James, Kevin J

    2009-11-01

    The tunicate Pyura chilensis (Molina, 1782); Phylum Chordata; Subphylum Urochordata; Class Ascidiacea, common local name "piure" or sea squirt; a filter-feeder (plankton and suspended particles) sessile species; may play an important role in monitoring domoic acid (DA) the principal toxic component of Amnesic Shellfish Poisoning (ASP). Significant DA concentrations have been determined in tunicate samples, collected during a recent ASP outbreak in Bahía Inglesa, an important scallop (Argopecten purpuratus) farming area. Several infaunal species were tested for the presence of DA, in addition to the usual scallop monitoring programme. DA was found at sub-toxic levels in filtering bivalves such as mussels (Mytilus chilensis), large mussels (Aulacomya ater) and clams (Protothaca thaca) (6.4, 5.4 and 4.7 microg DA/g tissue respectively). Of particular interest was the observation of significant accumulations of toxic Pseudo-nitzschia sp. diatoms in the internal siphon and atrium spaces of the tunicate. Toxin distribution within major tunicate organs was heterogeneous with 8.7-15.5 microg DA/g in edible tissues, 14.9-17.9 microg DA/g in the fecal material and 13.6-32.7 microg DA/g in the gut content. DA was determined by HPLC-UV and confirmed by diode-array detection and LC-MS/MS analysis. This is the first report of the presence of DA in a tunicate that is regularly consumed by coastal populations. These results confirm the need to include these organisms in sanitation programs for marine toxins.

  16. Spatio-temporal variation of microphytoplankton in the upwelling system of the south-eastern Arabian Sea during the summer monsoon of 2009

    Directory of Open Access Journals (Sweden)

    Lathika Cicily Thomas

    2013-02-01

    Full Text Available The phytoplankton standing crop was assessed in detail along the South Eastern Arabian Sea (SEAS during the different phases of coastal upwelling in 2009. During phase 1 intense upwelling was observed along the southern transects(8°N and 8.5°N. The maximum chlorophyll a concentration (22.7 mg m-3 was observedin the coastal waters off Thiruvananthapuram (8.5°N. Further north there was no signature of upwelling, with extensive Trichodesmium erythraeum blooms. Diatoms dominated in these upwelling regions with thecentric diatom Chaetoceros curvisetus being the dominant species along the 8°N transect. Along the 8.5°N transect pennate diatoms like Nitzschia seriata and Pseudo-nitzschia sp. dominated. Duringphase 2, upwelling of varying intensity was observed throughout the study area with maximum chlorophyll a concentrations along the 9°N transect (25 mg m-3 with Chaetoceros curvisetus as the dominantphytoplankton. Along the 8.5°N transect pennate diatoms during phase 1 were replaced by centric diatoms like Chaetoceros sp. The presence of solitary pennate diatoms Amphora sp. and Navicula sp.were significant in the waters off Kochi. Upwelling was waning during phase 3 and was confined to the coastal waters of the southern transects with the highest chlorophyll a concentration of 11.2 mg m-3. Along withdiatoms, dinoflagellate cell densities increased in phases 2 and 3. In the northern transects (9°N and 10°N the proportion of dinoflagellates was comparatively higher and was represented mainly by Protoperidinium spp.

  17. Diatom Transcriptional and Physiological Responses to Changes in Iron Bioavailability across Ocean Provinces

    Directory of Open Access Journals (Sweden)

    Natalie R. Cohen

    2017-11-01

    Full Text Available Changes in iron (Fe bioavailability influence diatom physiology and community composition, and thus have a profound impact on primary productivity and ecosystem dynamics. Iron limitation of diatom growth rates has been demonstrated in both oceanic and coastal waters of the Northeast Pacific Ocean and is predicted to become more pervasive in future oceans. However, it is unclear how the strategies utilized by phytoplankton to cope with low Fe bioavailability and resupply differ across these ocean provinces. We investigated the response of diatom communities to variable Fe conditions through incubation experiments performed in the Fe mosaic of the California Upwelling Zone and along a natural Fe gradient in the Northeast Pacific Ocean. Through coupling gene expression of two dominant diatom taxa (Pseudo-nitzschia and Thalassiosira with biological rate process measurements, we provide an in-depth examination of the physiological and molecular responses associated with varying Fe status. Following Fe enrichment, oceanic diatoms showed distinct differential expression of gene products involved in nitrogen assimilation, photosynthetic carbon fixation, and vitamin production compared to diatoms from low-Fe coastal sites, possibly driven by the chronic nature of Fe stress at the oceanic site. Genes of interest involved in Fe and N metabolism additionally exhibited divergent expression patterns between the two diatom taxa investigated, demonstrating that diverse diatoms may invoke alternative strategies when dealing with identical changes in their environment. We report here several mechanisms used distinctly by coastal or oceanic diatom communities as well as numerous taxa-specific strategies for coping with Fe stress and rearranging nutrient metabolism following Fe enrichment.

  18. Harmful algal bloom forecast system for SW Ireland. Part II: Are operational oceanographic models useful in a HAB warning system.

    Science.gov (United States)

    Cusack, Caroline; Dabrowski, Tomasz; Lyons, Kieran; Berry, Alan; Westbrook, Guy; Salas, Rafael; Duffy, Conor; Nolan, Glenn; Silke, Joe

    2016-03-01

    This study investigated the application of a three-dimensional physical hydrodynamic model in a harmful algal bloom forecast system for Bantry Bay, southwest Ireland. Modelled oceanographic conditions were studied and used to help understand observed changes in the chemical and biological patterns from the national biotoxins and phytoplankton monitoring program. The study focused on two toxic events in 2013. An upwelling event was predicted by the model prior to the appearance and population increase of potentially toxic diatoms, Pseudo-nitzschia, and associated domoic acid in shellfish. A downwelling episode was provided as a forecast in the model prior to the arrival of a Dinophysis bloom and detection of its associated biotoxins in Bay shellfish. The modelled forecast products developed included expected surface, mid-depth and bottom current pathways at the mouth of the Bay and on the adjacent shelf. The rate and direction of water volume flow at the mouth and mid-bay sections were produced by the model to examine predicted upwelling and downwelling pulses. The model also calculated the evolution of water properties (temperature, salinity and density) with depth along the Bay axis and on the adjacent continental shelf. Direct measurements of water properties at a fixed point, mid-bay, were comparable to model calculations. The operational model for southwest Ireland produces a reliable 3-day physical hydrodynamic forecast of the dominant regional physical processes that result in water exchange events between Bantry Bay and its adjacent shelf. While simulated physical hydrodynamics were provided as a 3-day forecast, the upwelling and downwelling signals from the model, closely linked to toxic HAB episodes, were evident up to 10 days prior to the contamination of shellfish in the Bay. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Ojelade et al (20)

    African Journals Online (AJOL)

    DELL

    Research (Clarke and Gorley, 2006). Ecological biotic indices of ... Bacillariophyceae (diatoms) dominated the phytoplankton community ... individuals (i.e. holoplankton and meropankton) belonging to nine taxa including the larva forms of fish and invertebrates were identified during the research. The result of the analysis ...

  20. Planktonic algae and cyanoprokaryotes as indicators of ecosystem ...

    African Journals Online (AJOL)

    2013-10-07

    Oct 7, 2013 ... However, results also show a change from a Chrysophyceae-dominated community to one dominated by. Bacillariophyceae. Increased ... as well as the underground located groundwater aquifers and springs in the karst landscape ...... Murray-Darling. Basin Commission, Canberra City, Australia. 307 pp.

  1. A study of Algal species of Kano River, Tamburawa, Kano State ...

    African Journals Online (AJOL)

    A total of fifty six (56) algal species were identified out of which thirty seven (37) species belong to the Class Bacillariophyceae with Nitzchia spp having the highest cell counts, Seventeen (17) species belong to the Class Chlorophyceae with Spirogyra spp having the highest cell counts, two species belong to the Class ...

  2. Response of food organisms to inorganic nitrogen availability ...

    African Journals Online (AJOL)

    Influence of inorganic N2 forms on pond food organisms was investigated. Seven identified plankton taxa comprising four phytoplankton: Desmidiaceae (desmids), Bacillariophyceae (diatoms), Cyanophyceae (blue-green algae) and Chlorophyceae (green algae) and three zooplankton: Protozoa, Cladocera and Rotifera ...

  3. Effect of pollution on phytoplankton occurrence and distribution in ...

    African Journals Online (AJOL)

    The phytoplankton distribution of some parts of River Kaduna receiving Industrial effluents was surveyed for a period of one year. A total number of 2166 specimens of phytoplankton represented by four major taxa namely: Chlorophyceae, Bacillariophyceae, Cyanophyceae and Dinophyceae, were encountered.

  4. Spring phytoplankton variability along a south coast of Sfax at the water-sediment interface (Tunisia, Eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    Amira Rekik

    2016-02-01

    Full Text Available Objective: To compare the composition of the phytoplankton classes during the two spring studies, to study whether the spatial distribution of the phytoplankton is stable or not between spring 2010 and spring 2011 and to estimate the abiotic factor that mostly affects the structure and the richness of phytoplankton. Methods: Phytoplankton sub-samples were counted under an inverted microscope using the Utermöhl method. Phytoplankton identification was made from morphological criteria after consulting various keys. Results: Results showed a significant difference from spring 2010 to spring 2011 regarding nitrate/phosphate ratio, with high value in spring 2010 (30.19 ± 25.70. Relatively low nitrate/phosphate ratio (1.13 ± 0.53 during spring 2011 might result from phosphogypsum. Phytoplankton was characterised by the proliferation of Bacillariophyceae (46%–78% of the total microphytoplankton and by the large number of Euglenophyceae. Thirty two Bacillariophyceae species were identified at every station, represented essentially by Amphora sp., Navicula sp., Coscinodiscus sp. and Grammatophora sp. The results advise that Bacillariophyceae are usually adapted to particular ecological environment. Conclusions: This study shows that hydrological conditions in the south coast of Sfax present a high spatial and seasonal variability. The phytoplankton community distribution showed clear variations along the coastal stations during a spring cruises conducted in May 2010 and May 2011. The phytoplankton community found along the coast was dominated by opportunistic Bacillariophyceae species.

  5. Taxa Composition, Abundance, Distribution And Diversity Of The ...

    African Journals Online (AJOL)

    Forty-eight genera of plankton were recorded; nine of Cyanophyceae, thirteen each of Chlorophyceae and Bacillariophyceae, seven of Protozoa and three each of Rotifera and Crustacea. Members of Cyanophyceae dominated the assemblage accounting for 91.77% of the total plankton abundance. All the major plankton ...

  6. Preliminary Studies on the Occurrence of Freshwater Epipelic Algae ...

    African Journals Online (AJOL)

    A total of 38 algal genera were identified over the period, with the Bacillariophyceae dominating with 19 genera followed by the Chlorophyta and the Cyanophyta with 13 and 6 genera, respectively. Fragilaria, Melosira and Rhizosolenia were the most abundant Bacillariophyta genera encountered. The Chlorophyta had ...

  7. Contrasting roles of water chemistry, lake morphology, land-use, climate and spatial processes in driving phytoplankton richness in the Danish landscape

    DEFF Research Database (Denmark)

    Özkan, Korhan; Jeppesen, Erik; Søndergaard, Martin

    2013-01-01

    were performed on permuted data 1,000 times. The local environment was described by lake water chemistry, lake morphology, land-use in lake catchments, and climate. Analysis of the effects of four groups of environmental factors on the richness of the main groups of phytoplankton revealed contrasting...... patterns. Lake water chemistry was the strongest predictor of phytoplankton richness for all groups, while lake morphology also had a strong influence on Bacillariophyceae, Cyanobacteria, Dinophyceae, and Euglenophyceae richness. Climate and land-use in catchments contributed only little to the explained...... variation in phytoplankton richness, although both factors had a significant effect on Bacillariophyceae richness. Notably, total nitrogen played a more important role for phytoplankton richness than total phosphorus. Overall, models accounted for ca. 30% of the variation in genus richness for all...

  8. THE FRESHWATER ALGAL FLORA OF THE “GIARA DI GESTURI” (SARDINIA, ITALY

    Directory of Open Access Journals (Sweden)

    S. Alfinito

    2013-04-01

    Full Text Available The "Giara di Gesturi" is a basaltic plateau placed in the central-southern part of Sardinia Island. The present study involves the algal flora of seven ephemeral ponds named “Paulis” present in the Giara. A total of 213 algal taxa were identified, distributed as follows in the different classes: Cyanophyceae: 16; Xanthophyceae: 1; Bacillariophyceae: 110; Dinophyceae: 4; Euglenophyceae: 10; Chlorophyceae: 42; Klebsormidiophyceae: 2; Zygnematophyceae: 28. From a qualitative point of view the Bacillariophyceae clearly predominate. The high biodiversity of these environments shows the extreme importance of the ephemeral pools in the Mediterranean environment. This preliminary study proves to be extremely promising and further researches are to be hoped.

  9. Especies del Fitoplancton Presentes en el Lago Tonatiahua, Morelos, México Especies del Fitoplancton Presentes en el Lago Tonatiahua, Morelos, México

    Directory of Open Access Journals (Sweden)

    Roberto Trejo Albarrán

    2012-02-01

    Full Text Available Se llevó a cabo un reconocimiento de las especies del fitoplancton del Lago Tonatiahua, Morelos, México, registrándose un total de 24 especies, incluidas en las siguientes clases: Chlorophyceae con 4 especies, Chlamydophyceae con 3 especies, Cyanophyceae con 3 especies, Euglenophyceae con 2 especies, Dinophyceae con 1 especie y Bacillariophyceae con 11, se da una descripción de cada una de ellas y la distribución que presentaron en la columna de agua durante el estudio. An examination of the phytoplankton species from the Tonatiahua lake of Morelos, Mexico was carried out. 24species were examinated. They were included in the following classification: Chlorophyceae with 4species, Chlamydophyceae with 3species, Cyanophyceae with 3 species, Euglenophyceae with 2 species, Dinophyceae with 1 species, Bacillariophyceae with 11 species, a description of each are and its distribution in a water column during the test are presented in this paper.

  10. Spatio-temporal patterns and predictions of phytoplankton assemblages in a subtropical river delta system

    DEFF Research Database (Denmark)

    Wang, Chao; Li, Xinhui; Wang, Xiangxiu

    2016-01-01

    Spatial and seasonal sampling within a subtropical river delta system, the Pearl River Delta (China), provided data to determine seasonal phytoplankton patterns and develop prediction models. The high nutrient levels and frequent water exchanges resulted in a phytoplankton community with greatest...... diversity of Bacillariophyceae and Chlorophyceae, and greatest biomass of Bacillariophyceae. Spatial and temporal distributions of phytoplankton assemblages were revealed using non-metric multidimensional scaling (NMDS). Five groups were established using hierarchical clustering based on species biomass...... similarities. These groups were distinct with respect to species richness, biomass and indicators, especially for groups representing spatial dimension. The Linear Discriminant Analysis (LDA) model indicated that the spatial patterns of phytoplankton assemblages were mostly explained by water quality variables...

  11. The variation of water quality in the outdoor concrete tank and earthen pond

    OpenAIRE

    Moody, F.O.

    2001-01-01

    The paper reports on the study carried out at the Federal College of Freshwater Fisheries and Technology (Nigeria) and the Hatchery Complex in 1997. The physico-chemical parameters of an earthen fish pond and concrete tank were analysed. The abundance and distribution of phytoplankton and zooplankton were recorded. A total of eight species of phytoplankton were observed. These species can be classified as Chlorophyceae (green algae), Bacillariophyceae (diatom algae) and Cyanophyta (blue-green...

  12. Benthic diatoms (Bacillariophyta) from seepages and streams on James Ross Island (NW Weddell Sea, Antarctica)

    Czech Academy of Sciences Publication Activity Database

    Kopalová, K.; Veselá, J.; Elster, Josef; Nedbalová, Linda; Komárek, Jiří; Van de Vijver, B.

    2012-01-01

    Roč. 145, č. 2 (2012), s. 190-208 ISSN 2032-3913 R&D Projects: GA MŠk ME 934; GA MŠk ME 945; GA ČR GA206/05/0253 Institutional research plan: CEZ:AV0Z60050516 Keywords : James Ross Island * Antarctic Peninsula * Bacillariophyceae Subject RIV: EF - Botanics Impact factor: 1.192, year: 2012

  13. Fast Regulation of Photosynthesis in Diatoms: Mechanisms, Evolution and Ecophysiology

    OpenAIRE

    Lavaud, Johann

    2007-01-01

    International audience; Diatoms (Bacillariophyceae, Heterokontophytes) are essential aquatic eukaryotes. Their role in the structure and ecology of most of the aquatic ecosystems is crucial. Especially, their photosynthetic activity is responsible for about a quarter of the Earth's primary productivity as large as the most productive terrestrial ecosystems, even though they represent only few percents of the total plant biomass on the planet. Both planktonic and benthic diatoms tend to domina...

  14. The influence of environmental variability on the biogeography of coccolithophores and diatoms in the Great Calcite Belt

    Directory of Open Access Journals (Sweden)

    H. E. K. Smith

    2017-11-01

    Full Text Available The Great Calcite Belt (GCB of the Southern Ocean is a region of elevated summertime upper ocean calcite concentration derived from coccolithophores, despite the region being known for its diatom predominance. The overlap of two major phytoplankton groups, coccolithophores and diatoms, in the dynamic frontal systems characteristic of this region provides an ideal setting to study environmental influences on the distribution of different species within these taxonomic groups. Samples for phytoplankton enumeration were collected from the upper mixed layer (30 m during two cruises, the first to the South Atlantic sector (January–February 2011; 60° W–15° E and 36–60° S and the second in the South Indian sector (February–March 2012; 40–120° E and 36–60° S. The species composition of coccolithophores and diatoms was examined using scanning electron microscopy at 27 stations across the Subtropical, Polar, and Subantarctic fronts. The influence of environmental parameters, such as sea surface temperature (SST, salinity, carbonate chemistry (pH, partial pressure of CO2 (pCO2, alkalinity, dissolved inorganic carbon, macronutrients (nitrate + nitrite, phosphate, silicic acid, ammonia, and mixed layer average irradiance, on species composition across the GCB was assessed statistically. Nanophytoplankton (cells 2–20 µm were the numerically abundant size group of biomineralizing phytoplankton across the GCB, with the coccolithophore Emiliania huxleyi and diatoms Fragilariopsis nana, F. pseudonana, and Pseudo-nitzschia spp. as the most numerically dominant and widely distributed. A combination of SST, macronutrient concentrations, and pCO2 provided the best statistical descriptors of the biogeographic variability in biomineralizing species composition between stations. Emiliania huxleyi occurred in silicic acid-depleted waters between the Subantarctic Front and the Polar Front, a favorable environment for this species

  15. Phytoplankton across Tropical and Subtropical Regions of the Atlantic, Indian and Pacific Oceans.

    Directory of Open Access Journals (Sweden)

    Marta Estrada

    principal component assemblage, including several pennate taxa, Planktoniella sol, Hemiaulus hauckii and Pseudo-nitzschia spp., in the divergence regions. Our findings indicate that consistent assemblages of co-occurring phytoplankton taxa can be identified and that their distribution is best explained by a combination in different degrees of both environmental and historical influences.

  16. Centers for Oceans and Human Health: a unified approach to the challenge of harmful algal blooms.

    Science.gov (United States)

    Erdner, Deana L; Dyble, Julianne; Parsons, Michael L; Stevens, Richard C; Hubbard, Katherine A; Wrabel, Michele L; Moore, Stephanie K; Lefebvre, Kathi A; Anderson, Donald M; Bienfang, Paul; Bidigare, Robert R; Parker, Micaela S; Moeller, Peter; Brand, Larry E; Trainer, Vera L

    2008-11-07

    Harmful algal blooms (HABs) are one focus of the national research initiatives on Oceans and Human Health (OHH) at NIEHS, NOAA and NSF. All of the OHH Centers, from the east coast to Hawaii, include one or more research projects devoted to studying HAB problems and their relationship to human health. The research shares common goals for understanding, monitoring and predicting HAB events to protect and improve human health: understanding the basic biology of the organisms; identifying how chemistry, hydrography and genetic diversity influence blooms; developing analytical methods and sensors for cells and toxins; understanding health effects of toxin exposure; and developing conceptual, empirical and numerical models of bloom dynamics. In the past several years, there has been significant progress toward all of the common goals. Several studies have elucidated the effects of environmental conditions and genetic heterogeneity on bloom dynamics. New methods have been developed or implemented for the detection of HAB cells and toxins, including genetic assays for Pseudo-nitzschia and Microcystis, and a biosensor for domoic acid. There have been advances in predictive models of blooms, most notably for the toxic dinoflagellates Alexandrium and Karenia. Other work is focused on the future, studying the ways in which climate change may affect HAB incidence, and assessing the threat from emerging HABs and toxins, such as the cyanobacterial neurotoxin beta-N-methylamino-L-alanine. Along the way, many challenges have been encountered that are common to the OHH Centers and also echo those of the wider HAB community. Long-term field data and basic biological information are needed to develop accurate models. Sensor development is hindered by the lack of simple and rapid assays for algal cells and especially toxins. It is also critical to adequately understand the human health effects of HAB toxins. Currently, we understand best the effects of acute toxicity, but almost

  17. Depuration and anatomical distribution of domoic acid in the surf clam Mesodesma donacium.

    Science.gov (United States)

    Álvarez, Gonzalo; Uribe, Eduardo; Regueiro, Jorge; Martin, Helena; Gajardo, Teresa; Jara, Lorena; Blanco, Juan

    2015-08-01

    In northern Chile, domoic acid (DA) has been detected in several bivalve species. In Mesodesma donacium, one of the most important commercial species for local fishermen, no information is available on depuration, or on the anatomical distribution of this toxin and its potential use as a palliative measure to minimize the consequences of ASP outbreaks. Deputation of DA is very fast in M. donacium, and can be adequately described by means of a two-compartment model. The estimated rates for the first and second compartments were 1.27 d(-1) and 0.24 d(-1), respectively, with a transfer rate between compartments of 0.75. Having high depuration rates protects this species from being affected by Pseudo-nitzschia blooms for an extended period of time. Taking this into account, the time in which the bivalves are unsafe for consumers is very short, and therefore the economic losses that could result by the DA outbreaks in local fisheries should be moderate. In relation to anatomical distribution, at least during the uptake phase, the toxin was evenly distributed within the soft tissues, with a total toxin burden corresponding to 27%, 32% and 41% for Digestive Gland (DG), Foot (FT) and Other Body Fractions (OBF), respectively. Since the contribution of each organ to the toxin concentration is a function of both weight contribution and toxin burden, the pattern of toxin distribution showed the following trend: "all other body fractions" (OBF) > Foot (FT) > Digestive Gland (DG). Thus, the highest concentration of DA, with a contribution close to 72%, corresponds to the edible tissues (OBF + FT), while the DG (non-edible tissue) only contributes the remaining 28%. Consequently, in view of the anatomical distribution of domoic acid in M. donacium, the elimination of the digestive gland does not substantially reduce the toxicity of the final product and therefore selective evisceration would not improve their quality for human consumption. Copyright © 2015 Elsevier Ltd

  18. Phytoplankton across Tropical and Subtropical Regions of the Atlantic, Indian and Pacific Oceans.

    Science.gov (United States)

    Estrada, Marta; Delgado, Maximino; Blasco, Dolors; Latasa, Mikel; Cabello, Ana María; Benítez-Barrios, Verónica; Fraile-Nuez, Eugenio; Mozetič, Patricija; Vidal, Montserrat

    2016-01-01

    component assemblage), including several pennate taxa, Planktoniella sol, Hemiaulus hauckii and Pseudo-nitzschia spp., in the divergence regions. Our findings indicate that consistent assemblages of co-occurring phytoplankton taxa can be identified and that their distribution is best explained by a combination in different degrees of both environmental and historical influences.

  19. Benthos microalgae of the Lebyazhy'i Ostrova Reserve in the Black Sea

    Directory of Open Access Journals (Sweden)

    Darya S. Balycheva

    2017-08-01

    Full Text Available The paper presents for the first time a list of the benthic microalgae of the Lebyazhy'i Ostrova Reserve, including the Karkinitsky Gulf and Sary-Bulatsky liman. During 2015 and 2016, 78 taxa were found: Bacillariophyta – 69, Cyanoprokaryota – 6, Haptophyta – 3. In the Karkinitsky Gulf 45 taxa were found, in the Sary-Bulatsky liman – 56 taxa. The Czekanovski-Sorensen similarity coefficient between these locality is 46%. The basis of the flora is diatoms: Cocconeis scutellum, Entomoneis alata, Halamphora coffeiformis, Nitzschia scalpelliformis, Pleurosigma angulatum, Pl. elongatum, Psammodictyon panduriforme, including Coronia daemeliana, Surirella striatula, Tryblionella circumsuta, which are rare for the microphytobenthos of the Crimean coast of the Black Sea. According to different classifications, dominant algae are benthic (86%, marine (49% and cosmopolite (30% species. Two potentially toxic species of diatoms, H. coffeiformis and Pseudo-nitzschia calliantha, were found once, 20 species of saprobionts – indicators of water quality were found. A comparison of the floras in the protected regions of the Black Sea between the Lebyazhy'i Ostrova Reserve and the Kazachya Bay Sanctuary showed 38 common species of benthic diatoms, in the Karadag Nature Reserve – 43 and in the Kazantip Nature Reserve (Azov Sea – 21. The total microalgae abundance of the epilithon of the stones of the Sary-Bulatsky liman varied from 81,000 to 331,000 cellscm-2, biomass – 0.012–0.018 mgcm-2, number of species – 11–13. A significant contribution was made by cyanobacteria, their average abundance reached 256,000 cellscm-2 and biomass – 0.007 mgcm-2. The abundance of diatoms varied from 48,000 to 75,000 cellscm-2, the biomass reached 0.011 mgcm-2 with the dominance of Seminavis ventricosa. The obtained data have shown the necessity of regular monitoring of the microphytobenthos of the Lebyazhy'i Ostrova Reserve in order to identify the qualitative

  20. Phytoplankton across Tropical and Subtropical Regions of the Atlantic, Indian and Pacific Oceans

    Science.gov (United States)

    Estrada, Marta; Delgado, Maximino; Blasco, Dolors; Latasa, Mikel; Cabello, Ana María; Benítez-Barrios, Verónica; Fraile-Nuez, Eugenio; Mozetič, Patricija; Vidal, Montserrat

    2016-01-01

    component assemblage), including several pennate taxa, Planktoniella sol, Hemiaulus hauckii and Pseudo-nitzschia spp., in the divergence regions. Our findings indicate that consistent assemblages of co-occurring phytoplankton taxa can be identified and that their distribution is best explained by a combination in different degrees of both environmental and historical influences. PMID:26982180

  1. Survey of the efficacy of a short fragment of the rbcL gene as a supplemental DNA barcode for diatoms.

    Science.gov (United States)

    MacGillivary, Michael L; Kaczmarska, Irena

    2011-01-01

    DNA barcoding is a tool that uses a short, standard segment of DNA to identify organisms. In diatoms, a consensus on an appropriate DNA barcode has not been reached, but several markers show promise. These include the 5.8S gene plus a fragment of the internal transcribed spacer 2 (ITS-2) of nuclear-encoded ribosomal RNA, a 420-bp segment of the 18S rRNA gene, and a 748-bp fragment at the 3'-end of the ribulose bisophosphate carboxylase large subunit (rbcL) gene. Here, we tested a 540-bp fragment 417-bp downstream of the start codon of the rbcL gene for its efficacy in distinguishing diatom species in a wide range of taxa. Overall, 381 sequences representing 66 genera and 245 species from the classes Mediophyceae and Bacillariophyceae were examined. Intra/interspecific thresholds were set at p = 0.01 differences per site (diff./site) for Mediophyceae and p = 0.02 diff./site for Bacillariophyceae and correctly segregated 96% and 93% of morphological congeners, respectively. When testing reproductively isolated or biological species, which are only available from Bacillariophyceae, 80% of species were discriminated. Therefore, we concluded that, alone, the rbcL region tested herein as potential a DNA barcode was not a sufficient discriminator of all diatoms. We suggest that this fragment could be used in a dual-locus barcode with the more variable 5.8S+ITS-2 to discriminate species without sufficient interspecific divergences in the tested rbcL region and to provide insight into species identity from a separately evolved genome. © 2011 The Author(s) Journal of Eukaryotic Microbiology © 2011 International Society of Protistologists.

  2. Spatial and temporal patterns of phytoplankton composition in Burullus Lagoon, Southern Mediterranean Coast, Egypt

    Directory of Open Access Journals (Sweden)

    Mohamed Zein Alabedin Nassar

    2014-01-01

    Full Text Available Burullus Lagoon is a shallow, turbid, and nutrient replete system, suffering from high level of aquatic plants, expansion in fish farming and agricultural drainage discharges. Phytoplankton was evaluated based on four years monitoring seasonally from summer 2009 to spring 2013 at 12 stations representing the eastern, central and western basins of the lagoon. Over the 4-year study period, a total of 283 taxa from 96 genera and eight classes were recorded. The lagoon showed a pronounced algal periodicity. Phytoplankton community was generally dominated by Chlorophyceae, Bacillariophyceae and Cyanobacteria. The western basin had the lowest mean salinity values and highest phytoplankton abundance, in which, blooms of Chlorophyceae, Bacillariophyceae and Cyanobacteria were common. The eastern basin had lowest phytoplankton density and chlorophytes were dominant followed by Bacillariophyceae and/or Cyanobacteria. Euglenophyceae strongly appeared in the eastern basin especially at the second station, which is located in front of El Burullus Drain. The central basin is subjecting to high loading of phosphorus and nitrogen from agricultural drains and had a prevalence of chlorophyte blooms which constituted more than 50% of the total abundance. This study has provided substantial evidence that the phytoplankton abundance and community are governed by the environmental conditions which vary each year, so does the phytoplankton seasonal succession. Generally, about 25-50% reduction was recorded in the phytoplankton densities between 2009 and 2013 and a dramatic decrease in the abundance of many nuisance and eutrophic species was evident. No sign of eutrophication was observed, and recession of Cyanobacteria blooming suggests a major improvement in the water quality of Burullus Lagoon.

  3. IMPACT OF JUTE RETTING ON PHYTOPLANKTON DIVERSITY AND AQUATIC HEALTH: BIOMONITORING IN A TROPICAL OXBOW LAKE

    Directory of Open Access Journals (Sweden)

    Dipankar Ghosh

    2015-11-01

    Full Text Available Phytoplankton acts as a primary producer and biological filter of aquatic ecosystem. Jute retting during monsoon is a common anthropological activity in the rural Bengal. Quantitative seasonal bio-monitoring of phytoplankton community composition with relative abundance and its diversity indices was carried out in this study from April 2013 to March 2014 to assess water quality and the impact of jute retting on phytoplankton diversity of a tropical fresh water oxbow lake in Nadia district of India. We recorded a total of 34 genera of 5 distinct classes, Chlorophyceae (15, Bacillariophyceae (13, Cyanophyceae (4, Dinophyceae (1 and Euglenophyceae (1. Members of Chlorophyceae dominated throughout the year. Unlike Cyanophyceae, Bacillariophyceae was found to be significantly increased during monsoon when compared to the rest of the year. Average phytoplankton density was highest in post-monsoon (8760/L followed by monsoon (4680/L and pre-monsoon (3650/L. Owing to the dominance of class Chlorophyceae and Bacillariophyceae we found this lake to be oligotrophic to mesotrophic. Indices values of genera richness, Shannon-Wiener, evenness and Simpson’s diversity reached their lowest 14, 1.61, 0.61 and 0.68 in monsoon and highest 23, 2.42, 0.77 and 0.86 in post monsoon respectively. The lowest diversity values during monsoon clearly suggested that the selected lake has highest anthropogenic pollution due to jute retting which impacted significantly on phytoplankton diversity. Therefore, the lake is not conducive for fish growth especially during monsoon and we opine that there is a need to regulate jute retting process, intensity and its density in the lake during the monsoon to ensure enhanced biodiversity for sustainable management and conservation of aquatic environment of this Oxbow lake.

  4. Phytoplankton diversity of the Gharni Reservoir in Latur district, Maharashtra, India

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    Vishwas Balasaheb Sakhare

    2015-08-01

    Full Text Available The phytoplanktonic samples were collected from the Gharni Reservoir of Latur district of Maharashtra for a period of one year, from June 2013 to May 2014. Totally 18 species of phytoplankton belonging to different taxonomic groups were identified. Among these 7 species belong to Chlorophyceae, 5 species to Cyanophyceae, 3 species to Bacillariophyceae and 3 species to Euglenophyceae. The phytoplankton productivity fluctuated seasonally and the maximum number of 560 units/liter was recorded during month of February and March and minimum number of 95 units/liter during the month of September.

  5. Associative dependence among plankton and macrophytes as pollution markers at tropical lentic environ, Gujarat, India

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    Hiren B Soni

    2014-05-01

    Full Text Available The present research was undertaken at three sampling stations of Gomti catchment, Central Gujarat, India, to study dominance, interaction, and interdependence among biotic components (phytoplankton, zooplankton and aquatic macrophytes. The phytoplankton population was represented by 39 genera and 48 species belongs to family Bacillariophyceae (21 species, followed by Cyanophyceae (7, Cholorophyceae (18, and Euglenophyceae (2. In total, seven classes of zooplankton were represented by 36 genera and 39 species. Zooplankton dominance was reflected by class Ciliophora (16 species, followed by Zooflagellata, Rhizopoda and Rotifera (6 each, and Cladocera (3,and least by Copepoda and Ostracoda (1 species each. Of 16 species of aquatic macrophytes, 3 (18.75% were abundant, 4 (25% common, and 9 (56.25% were rare. The indices (Palmer, Nygaard’s, and Macrophyte index were determined to delineate the interdependent relationship among studied biotic components. Strong association was observed between Chlorophyceae and Bacillariophyceae, Ostracods and Ciliophorans, and Cladocerans and Bacillariophyceans. The detailed results of indices and interdependent associations among biotic components are discussed. The information provided herewith makes an insight for better understanding of the environmental aspects to be addressed effectively for the better protection, conservation, and management of Gomti reservoir, Gujarat, India. DOI: http://dx.doi.org/10.3126/ije.v3i2.10528 International Journal of the Environment Vol.3(2 2014: 175-191

  6. Phytoplankton distribution and community structure in estuary and fishpond at Subang, Blanakan, West Java

    Science.gov (United States)

    Amadea, E.; Takarina, N. D.; Wardhana, W.

    2017-07-01

    Phytoplankton plays an important role as primary producer and denotes the fertility of territorial waters. Samples were taken from a fishpond and estuary on August 27th, 2016 at Subang, West Java. The purpose of this research was to understand how the distribution and community structure of phytoplankton on fishpond and estuary differ. The result showed that phytoplankton found were composed by 6 classes: Cyanophyceae, Euglenophyceae, Chlorophyceae, Bacillariophyceae, Dinophyceae, and Xanthophyceae. Dinophyceae was found only in estuary, and Xanthophyceae was found only in the fishpond. Index of diversity (H') in the estuary was 2.41 and value of evenness (E) was 0.73. In fishpond, the value of H' was 1.63 and the value of E was 0.59, which shows no significance difference between the two locations. However, there was a difference between the number of Bacillariophyceae and Euglenophyceae found in both locations, and the difference between classes of phytoplankton found shows there might be some relations to the environmental parameters.

  7. Relation on phitoplankton community with Litopenaeus vannamei productivity in biocrete pond

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    T. Budiardi

    2007-07-01

    Full Text Available ABSTRACTManagement of phytoplankton is generally conducted by controlling the concentration of organic matter, fertilization and water exchange.  Organic materials are from uneaten feed and excretion of shrimp.  By using post facto method it was found four class of phytoplankton in biocrete pond at one cycle rearing of white shrimp (Litopenaeus vannamei.  Population at early rearing period was dominated by Bacillariophyceae (50.4%; 13 species and Cyanophyceae (42.41%; 1 species, followed by Dynophyceae (6.2%; 5 species and Chlorophyceae (1.3%; 1 species.  Increment in phytoplankton density was followed by increment in chlorophyll-a and oxygen from photosynthesis, and productivity was 2132 kg/pond.Keywords: phytoplankton, white shrimp, Litopenaeus vannamei, biocrete pond ABSTRAKPengelolaan fitoplankton umumnya dilakukan dengan mengoptimalkan bahan organik serta pemupukan dan pergantian air. Bahan organik berasal dari pakan buatan yang tidak terkonsumsi (sisa pakan dan ekskresi dari udang. Dengan menggunakan metode post facto selama satu siklus pemeliharaan udang vaname (Litopenaeus vannamei pada tambak biocrete diperoleh empat kelas fitoplankton. Dominasi Bacillariophyceae (50,4%; 13 jenis, Cyanophyceae (42,41%; 1 jenis terjadi pada awal pemeliharaan yang diiukuti oleh Dynophyceae (6,2%; 5 jenis dan Chlorophyceae (1,3%; 1 jenis. Peningkatan kelimpahan fitoplankton secara keseluruhan diikuti oleh peningkatan kandungan klorofil-a dan oksigen hasil fotosintesis total sehingga produktifitasnya mencapai 2132 kg/petakKata kunci: fitoplankton, udang vaname, Litopenaeus vannamei, tambak biocrete

  8. Phytoplankton community of Lake Baskandi anua, Cachar District, Assam, North East India – An ecological study

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    Devi M.B.

    2016-01-01

    Full Text Available Diversity, relative abundance and dominance of phytoplankton community of the Lake Baskandi anua, an oxbow lake of Assam, North east India were studied during December 2009 to November 2010. Chlorophyll content and biomass of phytoplankton along with physico-chemical properties of water of the lake were also estimated. The lake is covered with Hydrilla and other macrophytes like Eichhornia, Trapa, Altrnenthera, Polygonum, Ludwizia sp., etc. Seasonal fluctuations of 41 genera of phytoplankton, belonging to 5 groups (Chlorophyceae, Cyanobacteria, Bacillariophyceae, Euglenophyceae and Dinophyceae were encountered in the lake. Chlorophyceae was found to be highest in winter, Cyanobacteria and Euglena in monsoon and Bacillariophyceae in pre monsoon. According to Engelmann’s scale, Spirogyra indica was found eudominant followed by 10 dominant, 24 subdominant and 20 recedent species. Chlorophyll- a content of phytoplankton varied from 14.18 to 33.89 μg·L-1, during the study period. One way analysis of variance (ANOVA revealed significant seasonal variation in physico-chemical properties of water like Water temperature, pH, Conductivity, Dissolved oxygen, Free CO2, Total alkalinity, Calcium, Chloride, Nitrate and Ammonia. Relationship between phytoplankton group assemblage and environmental variables were explored by the ordination method CCA (Canonical Correspondence Analysis.

  9. Biodiversity patterns of plankton assemblages at the extremes of the Red Sea

    KAUST Repository

    Pearman, John K.

    2016-01-07

    The diversity of microbial plankton has received limited attention in the main basin of the Red Sea. This study investigates changes in the community composition and structure of prokaryotes and eukaryotes at the extremes of the Red Sea along cross-shelf gradients and between the surface and deep chlorophyll maximum. Using molecular methods to target both the 16S and 18S rRNA genes, it was observed that the dominant prokaryotic classes were Acidimicrobiia, Alphaproteobacteria and Cyanobacteria, regardless of the region and depth. The eukaryotes Syndiniophyceae and Dinophyceae between them dominated in the north, with Bacillariophyceae and Mamiellophyceae more prominent in the southern region. Significant differences were observed for prokaryotes and eukaryotes for region, depth and distance from shore. Similarly, it was noticed that communities became less similar with increasing distance from the shore. Canonical correspondence analysis at the class level showed that Mamiellophyceae and Bacillariophyceae correlated with increased nutrients and chlorophyll a found in the southern region, which is influenced by the input of Gulf of Aden Intermediate Water.

  10. Biodiversity patterns of plankton assemblages at the extremes of the Red Sea.

    Science.gov (United States)

    Pearman, J K; Kürten, S; Sarma, Y V B; Jones, B H; Carvalho, S

    2016-03-01

    The diversity of microbial plankton has received limited attention in the main basin of the Red Sea. This study investigates changes in the community composition and structure of prokaryotes and eukaryotes at the extremes of the Red Sea along cross-shelf gradients and between the surface and deep chlorophyll maximum. Using molecular methods to target both the 16S and 18S rRNA genes, it was observed that the dominant prokaryotic classes were Acidimicrobiia, Alphaproteobacteria and Cyanobacteria, regardless of the region and depth. The eukaryotes Syndiniophyceae and Dinophyceae between them dominated in the north, with Bacillariophyceae and Mamiellophyceae more prominent in the southern region. Significant differences were observed for prokaryotes and eukaryotes for region, depth and distance from shore. Similarly, it was noticed that communities became less similar with increasing distance from the shore. Canonical correspondence analysis at the class level showed that Mamiellophyceae and Bacillariophyceae correlated with increased nutrients and chlorophyll a found in the southern region, which is influenced by the input of Gulf of Aden Intermediate Water. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Seasonal variations in phytoplankton diversity in the Bui dam area of the Black Volta in Ghana during the pre- and post-impoundment periods

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    Elliot Haruna Alhassan

    2015-03-01

    Full Text Available Phytoplankton constitutes the primary producers of aquatic ecosystems and represents the food chain base that supports the commercial fisheries of most water bodies. Nowadays, there is lack of information on phytoplankton assemblages of most reservoirs in Africa. To contribute with this knowledge, this study was carried out to determine the density and diversity of seasonal variations of phytoplankton species in the Bui dam area of the Black Volta, during the pre- (2011 and post-impoundment (2012 periods. For this, a three-level stratified random sampling approach was adopted for 22 months. Phytoplankton samples were obtained by towing a 0.5m diameter phytoplankton net (35μm mesh size and 0.25m² mouth surface area from a non-motorized canoe through a distance of about 100m against the current from downstream to upstream of the river. In 2011, 35 species of phytoplankton belonging to four classes, Bacillariophyceae (7.6%, Chlorophyceae (43%, Cyanophyceae (48.6% and Euglenophyceae (0.8% were identified. In the 2012 sampling, 18 species belonging to three classes, Bacillariophyceae (2.2%, Chlorophyceae (26.1% and Cyanophyceae (71.7% were observed. A total of 17 species of phytoplankton, including Gyrosigma sp., Surirella sp., Carteria sp., Chlosterium sp., Chlorogonium sp., Coelastrum sp., Cosmarium sp., Volvox sp., Chroococcus sp., Coelosphaerium sp., Rivularia sp. and Spirulina sp., were absent during the late post-impoundment period. Mean monthly total phytoplankton abundance decreased from June (7 384 cells/m³ to August (106cells/m³ in 2011. In 2012 however, mean total phytoplankton decreased from February (1 237cells/m³ to August (4cells/m³. The results also showed that variations occurred between seasons among some phytoplankton groups. The dry and pre-wet seasons had significantly (p<0.05 higher mean phytoplankton abundance than the wet season during the 22 months of sampling period. The biotic indices of Shannon-Wiener (H¹ were

  12. Seasonal phytoplanktonic diversity of Kitham lake, Agra.

    Science.gov (United States)

    Tiwari, Ashesh; Chauhan, S V S

    2006-01-01

    Two years (Jan. 2000 - Dec. 2001) data on the seasonal studies of phytoplanktonic diversity of Kitham lake (Sur Sarovar) Agra revealed the presence of 73 algal species. A limited number of these were recorded throughout the year, while others were distributed in different seasons mainly in winter and summer seasons. During winters, Chlorophyceae was the most dominant group followed by Bacillariophyceae. On the other hand, Cyanophyceae and Euglenophyceae were the most dominant during summers. Certain species e.g. Pandorina morum, Pediastrum tetras, Gonium sp., Chlorella vulgaris, Scendesmus quadricauda, Oedogonium cardiocum, Synedra ulna, Oscillatoria agardhii and Euglena gracillis were recorded throughout the year. Chlorella, Stigeoclonium, Pandorina, Micratinium, Oscillatoria, Anacystis, Nitzschia and Cymbella were found to be good indicators of water pollution.

  13. Carotenoids, Phenolic Compounds and Tocopherols Contribute to the Antioxidative Properties of Some Microalgae Species Grown on Industrial Wastewater

    DEFF Research Database (Denmark)

    Safafar, Hamed; van Wagenen, Jonathan Myerson; Møller, Per

    2015-01-01

    sp., and Desmodesmus sp. (Chlorophyta), were screened for their antioxidant properties using different in vitro assays. Natural antioxidants, including pigments, phenolics, and tocopherols, were measured in methanolic extracts of microalgae biomass. Highest and lowest concentrations of pigments...... activity in all antioxidant tests while carotenoids were found to contribute to the 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity, ferrous reduction power (FRAP), and ABTS-radical scavenging capacity activity. Desmodesmus sp. biomass represented a potentially rich source of natural......This study aimed at investigating the potential of microalgae species grown on industrial waste water as a new source of natural antioxidants. Six microalgae from different classes, including Phaeodactylum sp. (Bacillariophyceae), Nannochloropsis sp. (Eustigmatophyceae), Chlorella sp., Dunaniella...

  14. Algas perifíticas em dois ambientes do baixo rio Doce (lagoa Juparanã e rio Pequeno – Linhares, Estado do Espírito Santo, Brasil: variação espacial e temporal - DOI: 10.4025/actascibiolsci.v30i4.535 Periphytic algae in two environments of the lower Doce river (Juparanã lagoon and Pequeno river – Linhares, Espírito Santo State, Brazil: spatial and temporal variation - DOI: 10.4025/actascibiolsci.v30i4.535

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    Bruna Cavati

    2008-11-01

    Full Text Available A pesquisa objetivou avaliar a variação espacial e temporal da comunidade de algas perifíticas em dois ambientes do baixo rio Doce: lagoa Juparanã e rio Pequeno. Foram realizadas coletas trimestrais (agosto/04 a maio/05 em duas estações amostrais, uma na lagoa e outra no rio. Foram coletados pecíolos de Eichhornia azurea (Sw. Kunth. Os atributos da comunidade analisados foram: riqueza de táxons, freqüência de ocorrência, densidade, abundância e dominância. Na lagoa Juparanã, foram registrados 86 táxons e a densidade variou de 20.592 ind cm-2 (mai/05 a 88.712 ind cm-2 (nov/04. No rio Pequeno, foram registrados 83 táxons e a densidade variou de 16.049 ind cm-2 (fev/05 a 71.663 ind cm-2 (ago/04. Em ambos os ambientes, as classes predominantes qualitativamente foram Cyanophyceae, Bacillariophyceae e Zygnemaphyceae, havendo domínio das formas filamentosas e unicelulares seguidas das coloniais. As classes Cyanophyceae e Bacillariophyceae foram mais representativas quantitativamente. Não houve variação espacial. Pluviosidade, temperatura da água, condutividade elétrica e transparência foram as variáveis que mais oscilaram conforme a estação (seca ou chuvosa e as que apresentaram maior número de correlações significativas com as variáveis biológicas, evidenciando heterogeneidade temporal.This research aimed to evaluate the spatial and temporal variation of the periphytic algae community within two environments of the lower Doce River: Juparanã Lagoon and Pequeno River. Samplings were carried out every three months from August 2004 to May 2005 at both sites. Natural substrata of Eichhornia azurea (Sw. Kunth petioles were collected from the sites. The community was analyzed according to species richness, frequency of occurrence, density of organisms, abundance and dominancy. Eighty-six taxa were recorded in the lagoon, and the density of organisms varied from 20,595 ind cm-2 (May/05 to 88,712 ind cm-2 (Nov/04. Eighty

  15. Algas perifíticas em dois ambientes do baixo rio Doce (lagoa Juparanã e rio Pequeno – Linhares, Estado do Espírito Santo, Brasil: variação espacial e temporal = Periphytic algae in two environments of the lower Doce river (Juparanã lagoon and Pequeno river – Linhares, Espírito Santo State, Brazil: spatial and temporal variation

    Directory of Open Access Journals (Sweden)

    Bruna Cavati

    2008-10-01

    Full Text Available A pesquisa objetivou avaliar a variação espacial e temporal da comunidade de algas perifíticas em dois ambientes do baixo rio Doce: lagoa Juparanã e rio Pequeno. Foram realizadas coletas trimestrais (agosto/04 a maio/05 em duas estações amostrais, uma na lagoae outra no rio. Foram coletados pecíolos de Eichhornia azurea (Sw. Kunth. Os atributos da comunidade analisados foram: riqueza de táxons, freqüência de ocorrência, densidade, abundância e dominância. Na lagoa Juparanã, foram registrados 86 táxons e a densidadevariou de 20.592 ind cm-2 (mai/05 a 88.712 ind. cm-2 (nov/04. No rio Pequeno, foram registrados 83 táxons e a densidade variou de 16.049 ind. cm-2 (fev/05 a 71.663 ind. cm-2 (ago/04. Em ambos os ambientes, as classes predominantes qualitativamente foramCyanophyceae, Bacillariophyceae e Zygnemaphyceae, havendo domínio das formas filamentosas e unicelulares seguidas das coloniais. As classes Cyanophyceae e Bacillariophyceae foram mais representativas quantitativamente. Não houve variação espacial. Pluviosidade, temperatura da água, condutividade elétrica e transparência foram asvariáveis que mais oscilaram conforme a estação (seca ou chuvosa e as que apresentaram maior número de correlações significativas com as variáveis biológicas, evidenciando heterogeneidade temporal.This research aimed to evaluate the spatial and temporal variation of the periphytic algae community within two environments of the lower Doce River: Juparanã Lagoon and Pequeno River. Samplings were carried out every three months from August 2004 to May 2005 at both sites. Natural substrata of Eichhornia azurea (Sw. Kunth petioles were collected from the sites. The community was analyzed according to species richness, frequency of occurrence, density of organisms, abundance and dominancy. Eighty-six taxa were recorded in the lagoon,and the density of organisms varied from 20,595 ind. cm-2 (May/05 to 88,712 ind. cm-2 (Nov/04. Eighty

  16. Preliminary Observations On Phytoplankton At Sacred Palustrine Habitat, Central Gujarat, India

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    Hiren B Soni

    2013-12-01

    Full Text Available The aim of the present study was to depict the phytoplankton composition of Sacred Palustrine Habitat (SPH, Anand District, Central Gujarat, India. Collections of phytoplankton were carried out at three permanent sampling stations on monthly basis for one year (June 2012 to May 2013. The phytoplankton population was represented by 39 genera and 48 species belongs to family Bacillariophyceae (21 species, followed by Cyanophyceae (7 species, Cholorophyceae (18 species, and Euglenophyceae (2 species. Species such as Ankistrodesmus convolutus Corda, Closteriopsis longissima Lemmermann, Oscillatoria perornata Skuja, Oscillatoria subbrevis Schmidle, Syndrea ulna (Nitzsch Ehrenberg, were found abundant at all the study sites, while some species were rare 56.25% (n=27. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 115-126 DOI: http://dx.doi.org/10.3126/ije.v2i1.9215

  17. Pemanfaatan Plankton sebagai Sumber Makanan Ikan Bandeng di Waduk Ir. H. Juanda, Jawa Barat

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    Deden Ibnu Aqil

    2016-03-01

    Full Text Available Introducing of Milkfish (Chanos chanos was aimed to utilize natural food from plankton that were abundant in Ir. H. Juanda Reservoir, West Java. This research aimed to know plankton utilization by Milkfish in Ir. H. Juanda Reservoir, West Java. The research was conducted from February to July 2010 at 4 stations of sampling which representing the reservoir condition. The fishes collected based on the catch of fishermen. The sample was analyzed in physiology laboratory of Center Research for Limnology. The result of this research showed that the main food were plankton 43%, detritus 46%, and complement food were vegetation 11%. The domination food from the phytoplankton were Bacillariophyceae and zooplankton were Copepoda.

  18. Abundance and seasonal variations of phytoplankton in the creek waters of western mangrove of Kachchh-Gujarat.

    Science.gov (United States)

    Saravanakumar, A; Rajkumar, M; Thivakaran, G A; Serebiah, J Sesh

    2008-03-01

    The phytoplankton was assessed quantitatively and qualitatively in regard to their abundance in creek waters at three sites along the western mangrove of Kachchh. In total one hundred and four species of phytoplankton were identified. Among them 82 species diatoms (Bacillariophyceae), 16 species dinoflagellates (Dinophyceae), 3 species blue greens (Cyanophyceae) and 2 species were green algae. The density in all the three sites varied from 94,166.67 to 2,44,500 cells l(-1). The salinity ranged from 36 to 44 per thousand, temperature 17 to 35 degrees C and pH ranged from 7 to 8.9 respectively. These semi arid zone mangrove creek area having high densities were recorded during monsoon and early winter season.

  19. [Trophic ecology in tadpoles of Rhinella arenarum (Anura: Bufonidae) in agroecosystems and their possible implications for conservation].

    Science.gov (United States)

    Bionda, Clarisa; Gari, Noemi; Luque, Elisa; Salas, Nancy; Lajmanovich, Rafael; Martino, Adolfo

    2012-06-01

    The progress of the agriculture border has led an important loss of natural habitats, with significant consequences for biodiversity. In this sense, the studies in anuran amphibian tadpoles inhabiting these environments are relevant, because the larval stage is a phase of population regulation. The aim of this study was to analyze the body condition and diet in Rhinella arenarum, tadpoles, an anuran species widely distributed in South America and that inhabit agroecosystems. Three sites were sampled, two agroecosystems with different alteration degrees (C1 and C2) and an uncultured (SM) third place. The captured tadpoles were anesthetized, fixed and preserved in formaldehyde (10%). Subsequently, body measurements were made and the complete intestine was removed and analyzed for food items under a binocular microscope. The diet in R. arenarum tadpoles has a dominance of algae Bacillariophyceae, followed by Cyanophyceae. In particular, the class Bacillariophyceae, due to the presence of the genus Navicula, Nitzschia, Gomphonema and Hantzschia, was important in the diet of the anurans in those agroecosystems. Class Cyanophyceae, mainly represented by genus Oscillatoria and Euglenophyceae represented by Euglena and Strombomonas, were predominant in the diet of the anurans in SM. Some differences in the total items consumed by tadpole were observed between the studied sites. Tadpoles that inhabit the modified sites (C1 and C2) recorded a significantly smaller amount of food. Moreover, the tadpoles that inhabit these sites showed a lower body condition. The presence of certain algae associated with eutrophic environments, could indicate some pollution in agroecosystems (C1 and C2). Food resources would be lesser in places with strong agricultural activity, possibly with a greater degree of eutrophication. A smaller food amount could have consequences at population level for the short and long time terms, because of its impact on individual growth. Larval diet is

  20. Phytoplankton abundance in relation to the quality of the coastal water – Arabian Gulf, Saudi Arabia

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    Mostafa Abdel Mohsen El Gammal

    2017-12-01

    Full Text Available Phytoplankton abundance in relation to some physicochemical characters of the costal water of Arabian Gulf (Saudi Arabia was studied for one year. The sampling program included 15 locations in Dammam, Saihat, Al-Qatif, Al-Awamia and Safwa. Water samples were analyzed monthly for these parameters; temperature, pH, salinity, dissolved oxygen, nitrite, nitrate, ammonia, carbon dioxide, total chloride, reactive orthophosphate and total phosphorus and alkalinity, also phytoplankton communities were identified and Chlorophyll a was estimated. The results showed that, the high phytoplankton density attaining the maximum (190.3 × 104/m3 during May and June, and the minimum (10.4 × 104/m3 during November and December. Forty Five species belonging to 5 phytoplankton groups were recorded. Bacillariophyceae was the first dominant group forming 48% of the total phytoplankton communities (23 species. The dominant species of Bacillariophyceae were Pleurosigma strigosum, Pleurosigma elongatum, Lyrella clavata, Rhizosolenia shrubsolei, Cylindrotheca closterium, Nitzschia panduriform, Nitzschia longissimia, Amphora sp and Stephanopyxis. Dinophyceae was the second dominant group and formed 31% of the total phytoplankton communities (10 species; the dominant species were Ceratium fusus, Heterosigma sp, Ceratium furca, Prorocentrum triestium, Protoperidinium sp, Gyrodinium spirale, Noctiluca scintillans and Scrippsiella trochoidea. Cyanophyceae formed 13% (5 species where Nostoc sp, Oscillatoria and Merismopedia sp were the dominant species. Chlorophyceae had 8% (6 species; Scendesmus sp., Chlorella sp., Chlamydomonas sp., Dunaliella salina and Nannochloropsis sp were the dominant species. The Euglinophyceae was rare only one species (Euglina sp. The relationship was positive between the phytoplankton, chlorophyll a and carbon dioxide while negative amongst dissolved oxygen and total nitrogen. This research indicated that the relation between water quality

  1. Ecological Study of Periphytic Algal Community of Doodh Ganga and Khansha-Mansha Streams of Yusmarg Forests: A Health Resort of Kashmir Valley, India

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    Rafia Rashid

    2013-06-01

    Full Text Available The present study on Doodh Ganga and Khansha-Mansha streams of Yusmarg forests deals with the general ecological studies on periphytic algal community in terms of species composition and density. During the present investigation the periphytic algal community of Doodh Ganga and Khansha-Mansha streams were represented by 30 taxa which belonged to 4 major classes namely Bacillariophyceae (14, Chlorophyceae (11, Cyanophyceae (4 and Euglenophyceae (1. The most common periphytic species encountered across all the sites included Closterium sp., Zygnema sp., Amphora sp., Cymbella sp., Epithemia sp., Fragilaria sp., Navicula sp., Synedra sp., Tabellaria sp., Lyngbya sp. and Phormidium sp. Among the two streams, Doodh Ganga showed large number of taxa (45 and Khansha-Mansha was having 37 taxa of periphyton. Bacillariophyceae was the dominant group both in diversity and density and included 14 taxa contributing 57% of total periphytic algal population. Cyanophyceae forming the second dominant class was represented by 4 genera comprising 22% of the total periphytic algae .Chlorophyceae ranked third in its dominance pattern with 11 genera forming 20% of all the periphytic algae. Euglenophyceae was represented by only one species of Euglena sp. forming 1% of all the periphytic algae and found only at site 2 (Doodh Ganga downstream.Amongst the study sites the highest (5.69 value of Shannon Weiner Index was found at Doodh Ganga upstream while as lowest (4.38 at Khansha-Mansha downstream. The primary conclusion is that the streams, having crystal clear water, and are free from pollution as Chlorophyceae are better represented in both the streams. Further, as a result of less anthropogenic pressures the quality of water is fairly good.

  2. MICROPHYTOBENTHOS IN THE VRANA LAKE (CRES ISLAND

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    Marija Tomec

    2003-06-01

    Full Text Available Lake Vrana represents one of the largest freshwater lakes on a relatively small and entirely karstified island. According to its physical and chemical factors, this lake is ologotrophic, monomictic, with winter circulation and thermal stratification in summer. Microphytobenthic investigations of the Lake were performed in November 1995, and in February, May, June, August and November of 1996 and 1997, respectively. During the investigations microphytobenthic samples have been collected at five locations (Figure 1: V1 (around 13 m depth, V2 (around 22 m depth, V3 (around 33 m depth, V4 (around 51 m depth and V5 (around 73 m depth. Qualitative microphytobenthic composition consisted of 138 microphytic species belonging to: Cyanobacteria, Bacillariophyceae and Chlorophyceae (Tables 1, 2. Bacillariophyceae were the most numerous (99 species or 71.7 %, with relative frequency from 1 to 6. Planktonic forms Campylodiscus noricus and Cyclotella radiosa were the most represented species in microphytobenthic structure. The groups Chlorophyceae and Cyanobacteria were represented with relatively small number of species, the former with 26 species or 18.8% and the latter with 13 species or 9.5%. Particular species of Chlorophyceae were represented individually in microphytobenthic structure with low relative frequency, mostly 1, except in the case of Mougeotia sp. which had relative frequency 3 at the locations V1 and V2. The filamentous algae of the genera Lyngbya and Phormidium were dominant among Cyanobacteria, with relative freguency from 1 to 5. From the total number of microphytobenthic species determined, 94 species or 68% belonged to saprobic indicators. Most of them were oligosaprobic to betamesosaprobic indicators. Based on indicator values for the determined microphytobenthic species, P–B saprobity index was ranging between 1.3 and 1.7 (Table 3, which suggests good quality of lake waters.

  3. MICROPHYTOBENTHOS IN THE SUTLA RIVER

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    Marija Tomec

    2009-10-01

    Full Text Available The Sutla river is a river along Croatian/Slovenian border. Its length is about 91 km, out of which 89 km in Croatia. Microphytobenthos investigations have been performed at six locations along the Sutla river on Croatian territory. Samples were collected from specific areas of characteristic habitats. Beside sample collection, basic physico–chemical parameters were measured: water temperature, pH values and quantity of water dissolved oxygen. Water temperature changed depending on air temperature and the depth of the river, ranging from 5.1ºC to 6.3ºC. pH values were between 7.77 and 8.14, and dissolved oxygen concentrations (mg/L O2 at the six locations ranged between 8.6 mg/L and 14.9 mg/L. Quantitative microphytobenthos composition comprised 87 microphythic species belonging to the systematic groups of Bacteriophyta, Cyanobacteria and Chrysophyta (Bacillariophyceae and Xanthophyceae. The most numerous group were the diatoms or Bacillariophyceae (76 species or 88.3%, with dominance of the species of the genera Achnanthes, Cocconeis, Cymbella, Gomphonema, Navicula, Nitzschia and Surirella. The group Cyanobacteria was represented with relatively small number of species (9 species or 10%, with the dominance of filamentous algae belonging to the genus Phormidium. From the total number of the determined microphytobenthic species, 73 species or 84% were indicators of saprobity. Most of them were beta–mezosaprobic indicators. Based on the indicator values of determined microphytobenthic species at six investigated locations, P–B saprobity index was in the range from 1.8 to 2.0. These values suggested that the water at the investigated part of the Sutla river belonged to the second class of Croatian Water Quality Directive.

  4. Fitoplancton del río Tehuantepec, Oaxaca, México y algunas relaciones biogeográficas

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    José L Moreno-Ruiz

    2008-03-01

    Full Text Available El fitoplancton recolectado en el río Tehuantepec con características limnéticas a eurihalinas se determinó, clasificó y comparó con información regional de México y Suramérica. Se incluyen valores indicadores y un código del listado florístico para facilitar el manejo de estas algas. Se determinó un total de 58 familias, 121 géneros, 273 especies, una subespecie, 75 variedades, 13 formas y un morfotipo, pertenecientes a las divisiones Bacillariophyta (42.0 %, Chlorophyta (29.0 %, Cyanoprocaryota (18.0 %, Euglenophyta (5.0 %, Dinophyta (3.0 %, Cryptophyta (2.0 % y Chrysophyta (1.0 %. Las familias mejor representadas fueron Scenedesmaceae (24 especies, Oocystaceae (22, Bacillariophyceae (21, Chaetocerotaceae (15 y Euglenaceae (14. Se establecen nuevos registros para México: cinco familias, ocho géneros, 72 especies, 45 variedades y ocho formas. En este río, que presenta una moderada calidad del agua, sobresalieron las especies Chroococcus turgidus, Microcystis flosaquae y Pseudanabaena limnetica (como productoras de mareas rojas.Phytoplankton from Tehuantepec River, Oaxaca, Mexico and some biogeographical relationships. Phytoplankton species collected from the limnetic to euryhaline sections of Tehuantepec River were identified, classified and compared with regional information from Mexico and South America. We collected 15 samples every three months from July 1997 through August 1998 with a 20 µm net and a van Dorn bottle. Indicator values and a code checklist are included. A total of 58 families, 121 genera, 273 species, one subspecies, 75 varieties, 13 forms and one morphotype were identified in the taxa Bacillariophyta (42.0 %, Chlorophyta (29.0 %, Cyanoprocaryota (18.0 %, Euglenophyta (5.0 %, Dinophyta (3.0 %, Cryptophyta (2.0 % and Chrysophyta (1.0 %. The predominant families were Scenedesmaceae (24 species, Oocystaceae (22, Bacillariophyceae (21, Chaetocerotaceae (15 and Euglenaceae (14. Five families, eight genera, 72

  5. Periphytic algal community in artificial and natural substratum in a tributary of the Rosana reservoir (Corvo Stream, Paraná State, Brazil - doi: 10.4025/actascibiolsci.v32i4.4627 Periphytic algal community in artificial and natural substratum in a tributary of the Rosana reservoir (Corvo Stream, Paraná State, Brazil - doi: 10.4025/actascibiolsci.v32i4.4627

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    Liliana Rodrigues

    2010-11-01

    Full Text Available Periphytic algal community in artificial and natural substratum in a tributary of the Rosana reservoir (Corvo Stream, Paraná State, Brazil. This study evaluated the heterogeneity in periphytic algal community, under the influence of time colonization on artificial substratum. We also examined which abiotic variables most influenced the community in natural and artificial substratum. Egeria najas Planchon was used as natural substratum, and a plastic plant, as artificial. This experiment was carried out in a lateral arm from Rosana Reservoir, formed by Corvo Stream (Paranapanema river basin, in the period from November 21st to December 12nd, 2003, characterized as a warm and rainy period. Changes in species composition were assessed using the similarity indices. 495 taxa were registered in the phycoperiphytic community, distributed in 133 genera and 11 classes. Zygnemaphyceae, Bacillariophyceae, Chlorophyceae and Cyanophyceae presented higher species number, in both substrata. Staurodesmus, Closterium, Staurastrum and Cosmarium (Desmidiales; Gomphonema and Eunotia (Pennales; Characium, Scenedesmus and Desmodesmus (Chlorococcales; Anabaena and Aphanocapsa (Nostocales and Chroococcales, respectively were the most species-rich genera. The epiphytic community reached the highest species richness in the 15th successional day. Regardless the substratum type, the number of species was probably related to the high concentrations of nutrients (phosphorus and nitrogen.Periphytic algal community in artificial and natural substratum in a tributary of the Rosana reservoir (Corvo Stream, Paraná State, Brazil. This study evaluated the heterogeneity in periphytic algal community, under the influence of time colonization on artificial substratum. We also examined which abiotic variables most influenced the community in natural and artificial substratum. Egeria najas Planchon was used as natural substratum, and a plastic plant, as artificial. This experiment was

  6. Coleção de microalgas de ambientes dulciaquícolas naturais da Bahia, Brasil, como potencial fonte para a produção de biocombustíveis: uma abordagem taxonômica Collection of microalgae from natural freshwater environments of Bahia, Brazil, as a potential source for biofuel production: a taxonomic approach

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    Maria Cristina de Queiroz Mendes

    2012-09-01

    Full Text Available O presente trabalho envolveu a identificação taxonômica de espécies nativas de microalgas (isoladas de ecossistemas dulciaquícolas localizados nos arredores de Salvador, Bahia integrantes da Coleção de Microalgas dulciaquícolas do LABIOMAR/IB/UFBA, visando estudos taxonômicos mais aprofundados (ultraestruturais e moleculares e experimentos que possam avaliar sua capacidade para suprir cadeias produtivas de biocombustíveis. As coletas foram realizadas nos arredores de Salvador, Bahia, Brasil. A identificação das espécies foi efetuada com base em caracteres morfológicos. Foram identificados 19 táxons, 12 em nível de espécie e nove em nível de gênero, sendo 14 Chlorophyceae (Chlamydomonas sp1, Chlamydomonas sp2, Chlamydomonas sp3, Chlamydocapsa bacillus (Teiling Fott, Chlorococcum sp1, Chlorococcum sp2, Coelastrum indicum Turn.. Coelastrum microporum Nägeli, Desmodesmus brasiliensis (Bohl. Hegew, Scenedesmum obliquus (Turpin Kütz, Ankistrodesmus falcatus (Corda Ralfs, Ankistrodesmus fusiformis Corda, Kirchneriella lunaris (Kirchner. Möbius, Pseudokirchneriella subcapitata (Korshikov F. Hindák, três Trebouxiophyceae (Botryococcus braunii Kütz., Botryococcus terribilis Komárek et Marvan e Chlorella vulgaris Beijerinck, uma Bacillariophyceae (Nitzschia sp. e uma Cyanobacteria (Synechocystis sp..This study identified native species of microalgae (maintained at LABIOMAR/IB/UFBA Collection of Freshwater Microalgae to indicate their potential to supply the biofuel production chain. Samples were collected in freshwater ecosystems around Salvador, Bahia, Brazil. Species identification was based in morphological characteristics. Nineteen species were isolated and identified, 12 at the level of species and nine at the level of genus: 14 Chlorophyceae (Chlamydomonas sp1, Chlamydomonas sp2, Chlamydomonas sp3, Chlamydocapsa bacillus (Teiling Fott, Chlorococcum sp1, Chlorococcum sp2, Coelastrum indicum Turn. Coelastrum microporum N

  7. Keragaman Plankton dan Kondisi Perairan Tambak Intensif dan Tradisional di Probolinggo Jawa Timur

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    Utojo Utojo

    2015-05-01

    Full Text Available This study aims to estimate the wealth and stability of traditional and intensive brackishwater pond waters through biological index calculation (diversity, uniformity and dominance of plankton in traditional and intensive brackishwater pond waters of Probolinggo Regency, East Java Province. Sampling plankton and water from the site, considered to represent the diversity of plankton and water stability of traditional and intensive brackishwater pond. Plankton was collected using a plankton net no. 25, then preserved using 1% lugol solution. Measurement of water quality variables include temperature, salinity, dissolved oxygen and pH, whereas the laboratory analyzes that Total Organic Matter (TOM, NO2, NO3, NH3, PO4, Total Suspended Solids (TSS, and Fe. Plankton identification using microscope and calculation with cell counting method. The results of analysis of plankton in intensive brackishwater pond waters are obtained as much as 23 genera consisting of 16 genera of phytoplankton were included into three classes, namely Bacillariophyceae as much as 5 genera, Cyanophyceae 3 genera, Dinophyceae and Chlorophyceae, each of the four genera, whereas zooplankton consisting of 7 genera are included into two classes, namely Crustaceae 6 genera and Rotatoria 1 genus. In traditional brackishwater pond earned as much as 13 genera consisting of 8 genera of phytoplankton were included into Bacillariophyceae 5 genera, Cyanophyceae 2 genera, and Dinophyceae 3 genera, whereas zooplankton consisting of three genera are included into class Crustaceae 2 genera and Rotatoria 1 genus. Plankton abundance in intensive brackishwater pond ranges 702 - 4269 ind./L, diversity index of 0.26 -2.38, uniformity index of 0.10 - 1.5, and dominance index of 0.02 - 0.68. In traditional brackishwater pond have an abundance of plankton range 134 - 776 ind./L, diversity index of 0.10 - 1.97, uniformity index of 0.08 - 1.0, and dominance index of 0.01 - 0.75. Traditional and

  8. Phytoplankton assemblage of a small, shallow, tropical African reservoir

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    Moshood K Mustapha

    2009-12-01

    Full Text Available I measured physico-chemical properties and phytoplankton in the small, shallow tropical reservoir of Oyun (Offa, Nigeria between January 2002 and December 2003. I identified 25 phytoplankton genera in three sampling stations. Bacillariophyceae dominated (75.3%, followed by Chlorophyceae (12.2%, Cyanobacteria (11.1% and Desmidiaceae (0.73%. The high amount of nutrients (e.g. nitrate, phosphate, sulphate and silica explain phytoplankton heterogeneity (pInvestigué las propiedades físico-químicas y el fitoplancton del pequeño embalse tropical Oyun (Offa, Nigeria entre enero de 2002 y diciembre de 2003, para determinar el efecto de las propiedades físico-químicas en el fitoplancton y la producción de peces. En las tres estaciones estudiadas identifiqué 25 géneros de fitoplancton pertenecientes a cuatro clases. Bacillariophyceae dominó (75.3%, seguida de Chlorophyceae (12.2%, Desmidiaceae (11.1% y Cianobacteria (0.73%. La gran cantidad de nutrientes (e.g. nitrato, fosfato, sulfato y sílice explica la heterogeneidad del fitoplancton (p<0.05, el cual fue abundante durante la época de lluvias. La zona de transición de la reserva tuvo el conjunto más rico y abundante. Las fluctuaciones en la densidad del fitoplancton fueron resultado de la concentración estacional de los nutrientes, la presión del forrajeo y la hidrología. El embalse es eutrófico con agua excelente y fitoplancton diverso, y por tanto su producción pesquera sería alta. Estas condiciones son consecuencia de estrategias como mejores prácticas de gestión de cuencas (BPM para controlar la eutroficación y la sedimentación, y el establecimiento de prioridades legales para un buen uso del agua. Recomiendo medidas adicionales contra la oligotrofía, la hipereutrofia, el exceso de fitoplancton, las cianobacterias tóxicas, las escorrentías de residuos orgánicos y el exceso de sales disueltas.

  9. The potency of plankton as natural food for hard-lipped barb larvae (Osteochilus hasselti C.V.

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    Niken Tunjung Murti Pratiwi

    2011-01-01

    Full Text Available Plankton is aquatic organism that can be utilized as natural food. Hard-lipped barb is one of herbivorous fish that most of its life using plankton as its food source. Growing phytoplankton in pond can be conducted by providing nutrient source, such as fertilizing.  In this study, we examined the growth of hard-lipped barb larvae related to the existence of natural food in different fertilized ponds.  Four types of fertilizer were applied i.e. 100% organic fertilizer (PO, mixing of 85% organic and 15% inorganic fertilizer (PCa, mixing of 60% organic and 40% inorganic fertilizer, and 100% inorganic fertilizer (PA. Hard-lipped barb larvae were put into ponds after fertilizing process. Plankton was observed in ponds and larval intestines (Index of Preponderance and Ivlev Index. The growth of hard-lipped barb larvae was also observed. The result showed that larvae tend to utilize phytoplankton from the class of Bacillariophyceae and zooplankton in the early of its life. Utilizing plankton with those compositions as natural food in the early period generates a good growth performance.  The best performance of growth was shown by larvae in PA treatment which utilized most on zooplankton in the early period. Key words: fertilizer, natural food, hard-lipped barb, plankton   ABSTRAK Plankton merupakan organisme akuatik yang dapat digunakan sebagai sumber pakan alami. Ikan nilem merupakan salah satu jenis ikan herbivora yang hampir sepanjang hidupnya memanfaatkan plankton sebagai sumber makanannya. Cara untuk menumbuhkan fitoplankton di kolam adalah dengan menyediakan sumber nutrien, di antaranya melalui pemupukan. Oleh karena itu, penelitian ini dilakukan untuk mempelajari tingkat pertumbuhan larva ikan nilem berkaitan dengan keberadaan pakan alami yang ditumbuhkan pada media dengan jenis pupuk berbeda. Dalam penelitian ini diterapkan empat jenis pupuk berbeda, yaitu 100% pupuk organik (PO, campuran 85% pupuk organik dan 15% pupuk anorganik (PCa

  10. Observações hidrobiológicas sobre a poluição do rio Capibaribe-Mirim, Pernambuco, Brasil Hydrobiological observations on pollution in the Capibaribe-Mirim River, Pernambuco, Brazil

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    Luiz Tavares de Lyra

    1976-01-01

    Full Text Available Foi estudada, do ponto de vista ecológico, a poluição da água do rio Capibaribe-Mirim. Foram feitas cerca de 40 coletas de material de janeiro a dezembro de 1974, compreendendo os períodos seco e chuvoso, em 6 estações distribuídas desde o alto curso do rio (perto de Macaparana até o médio curso (imediações de Goiana. Observaram-se 96 taxa entre espécies e variedades, sendo as mais frequëntes e dominantes as seguintes: Biddulphia laevis (Ehr. Hustedt, Synedra ulna (Nitzsch Ehr., Eunotia pectinalis (Kutz Rabenhost, Nitzschia sigma (Kutz W. Smith, Navicula cuspidata var. ambigua (Ehr. Cleve, Eunotia didyma Grunow, Amphora ovalis Kutz., Amphora coffeaeformis Agard, Hantzschia amphioxys (Ehr. Grunow, Nitzschia triblionella var. victoriae (H. Grunow, Pinnularia acrospheria Breb., Pinnularia mesolepta (Ehr. W. Smith, Rhopalodia gibberula (Ehr. O. Müller, Surirella ovata kutz. É dada especial atenção ás algas Bacillariophyceae e Chlorophyceae. São apresentados, em forma tabular, o inventário ecológico, os índices halóbicos e sapróbicos das espécies, e a freqüência e distribuição das diatomáceas nas diversas estações de coleta.Ecological studies on water pollution in the Capibaribe-Mirim river were carried out during a period of 12 months (January to December 1974 covering the dry and wet seasons. Six collecting stations were established, from the upper course of the river, near Macaparana town, to the middle course, near Goiana town. In about 40 collected samples, 96 taxons, including species and varieties, were found. Reports and comments were made on the microflora and microfauna observed, more attention having been given to the Bacillariophyceae and Chlorophyceae present in the samples. The most frequent and dominant species of diatoms were the following: Biddulphia laevis (Ehr. Hustedt, Synedra ulna (Nitzsch Ehr., Eunotia pectinalis (Kutz. Rabenhost, Nitzschia sigma (Kutz. W. Smith, Navicula cuspidata var. ambigua

  11. Diatomáceas epífitas em Galaxaura rugosa (J. Ellis & Solander J.V. Lamouroux (Rhodophyta no Arquipélago de Fernando de Noronha, PE, Nordeste do Brasil Epiphytic diatoms on Galaxaura rugosa (J. Ellis & Solander J.V. Lamouroux (Rhodophyta in Fernando de Noronha Archipelago, Pernambuco State, Northeast Brazil

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    Manoel Messias da Silva Costa

    2009-09-01

    Full Text Available Exemplares de Galaxaura rugosa (J. Ellis & Solander J.V. Lamouroux foram coletados nos meses de junho/2006 e junho/2007, em três localidades do Arquipélago de Fernando de Noronha (Atalaia, Porto e Cagarras, com o objetivo de identificar a flora das diatomáceas epífitas que habita o talo da alga. Foram identificados 52 táxons distribuídos nas classes: Coscinodiscophyceae (19%, Fragilariophyceae (21% e Bacillariophyceae (60% denotando uma dominância de indivíduos com simetria bilateral, os quais corresponderam a 81% da flora identificada. As seguintes espécies caracterizaram a estrutura florística das diatomáceas, pois foram encontradas em mais de 70% das amostras analisadas: Amphora sp., Biddulphia biddulphiana (J.E. Smith Boyer, Cocconeis scutellum Ehrenberg, Diploneis bombus Ehrenberg, Grammatophora marina (Lyngbye Kützing, Mastogloia binotata (Grunow Cleve, Navicula longa Grunow, Nitzschia sp., Psammodiscus nitidus (Gregory Round in Mann, Rhabdonema adriaticum Kützing, Trachyneis aspera (Ehrenberg Cleve e Tryblionella coarctata (Grunow Mann. A diversidade específica variou entre média à alta, com os menores valores correspondendo aos florescimentos de Amphora sp. (49,3%, Mastogloia binotata (42,1% e Nitzschia sp. (62,5%.Specimens of Galaxaura rugosa (J. Ellis & Solander J.V. Lamouroux were collected in June 2006 and June 2007 at three localities in Fernando de Noronha Archipelago (Atalaia, Porto and Cagarras, aiming to identify the epiphytic diatom flora that inhabits the algae thallus. A total of 52 taxa were identified, distributed in the classes Coscinodiscophyceae (19%, Fragilariophyceae (21% and Bacillariophyceae (60% with 81% dominance of individuals with pinnate symmetry. The following species characterized the floristic diatom structure being considered very frequent: Amphora sp., Biddulphia biddulphiana (J.E. Smith Boyer, Cocconeis scutellum Ehrenberg, Diploneis bombus Ehrenberg, Grammatophora marina (Lyngbye K

  12. Water age – a major factor controlling phytoplankton community structure in a reconnected dynamic floodplain (Danube, Regelsbrunn, Austria

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    Stefan PREINER

    2009-08-01

    Full Text Available The study was carried out during four years that span a gradient in hydrological connectivity between the Danube and its sidearm system at Regelsbrunn (Austria. We evaluated the influences of distinct periods of hydrological connectivity on the phytoplankton community structure itself, but also interferences with biotic processes (including community succession, competition and zooplankton grazing that may take place within the constraints set by the hydrological disturbance regime. Algal biomass was highly related to the hydrological regime: lowest amounts were detected either during flood events or at long-lasting periods of isolation; on the other hand intermediate connection led to maximum concentrations. During floods and throughout the cold season, Bacillariophyceae were dominating the algal community. Summer and elongated periods of isolation favoured Chlorophyta. Cryptophyta occurred in early autumn after two months disconnection from the main channel, Dinophyta and Cyanoprokaryota were only of minor importance. Multivariate statistical analyses showed that water age was the primary determinant of phytoplankton community structure in the side-arm system. Cluster analyses revealed 7 groups that were characterized by 169 indicator taxa. Groups were dominated by Bacillariophyceae (Nitzschia, Navicula, Cymbella, Fragilaria and Diatoma, while species belonging to the Chloro-, Eugleno- and Dinophyta were less abundant. Non-metric Multidimensional Scaling was used for a comparison of community similarity between the main channel and the side-arm system. During high connectivity temporal trends of phytoplankton similarity in the side-arm tracked closely the community patterns of the Danube which indicated a major influence of the main channel on phytoplankton community structure. During low connectivity the temporal trends of the communities from both sampling stations were less coupled. A Canonical Correspondence Analysis explained 89.7% of the

  13. Periphytic algae dynamics in lentic ecosystems in the Brazilian semiarid.

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    Cordeiro, R S; Barbosa, J E L; Lima, G Q; Barbosa, L G

    2017-01-01

    The hydrological periods drive the structure and organization of aquatic communities in semiarid regions. We hypothesize that a decrease of the precipitation during the dry period will favor the development of the periphytic algal community, leading to higher richness and density in this period. To test this hypothesis, we investigated the changes in the periphytic algal community structure in three shallow and eutrophic ecosystems of the Brazilian semiarid. The sampling was performed between 2007 and 2010 at two-mensal intervals. The sampling of periphytic algal was performed in aquatic macrophytes and rocks. The abiotic variables were analyzed simultaneously. Dominance in diatoms, cyanobacteria and chlorophytes, respectively, was observed in two periods. In the dry period, waters were alkaline and had high concentrations of nitrate and total phosphorus associated with the highest densities of Bacillariophyceae. In the rainy period the water was warmer, oxygenated and high concentrations of ammonia and soluble reactive phosphorus with diatoms remained dominant but with reduced density, while cyanobacteria and chlorophytes increased. Overall, periphytic algal community composition no responded to changes in the hydrological periods. However, the hydrological periods altered the dynamics of periphytic algal community, supported by the alternation of the most representative classes (diatoms and cyanobacteria) between the hydrologic periods. Our data suggest that the morphometric and chemical and physical characteristics of lentic aquatic ecosystems studied were more important in the dynamics of periphytic algal community than the hydrological periods and types of substrates.

  14. Microalgae population dynamics in photobioreactors with secondary sewage effluent as culture medium

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    Adriano E. Marchello

    2015-03-01

    Full Text Available Nitrogen and phosphorus present in sewage can be used for microalgae growth, possibiliting cost reduction in the production of microalgae at the same time that it decreases the eutrophication potential of the effluent. This research aimed at monitoring the native community of microalgae and coliform bacteria in a secondary effluent from anaerobic municipal sewage treatment. Two treatments (aerated and non-aerated were performed to grow microalgae under semi-controlled conditions in semi-closed photobioreactors in a greenhouse. The results showed no significant pH and coliforms (total and Escherichia coli variation between treatments. Nutrient concentrations were reduced supporting microalgae growth up to 107 cells.mL−1independent of aeration. Exponential growth was obtained from the first day for the non-aerated, but a 5 day lag phase of growth was obtained for the aerated. Chlorella vulgaris was the dominant microalgae (99.9% in both treatments. In the aerated, 5 algae classes were detected (Chlorophyceae, Cyanophyceae, Chrysophyceae, Bacillariophyceae and Euglenophyceae, with 12 taxa, whereas in the non-aerated, 2 classes were identified (Chlorophyceae and Cyanophyceae, with 5 taxa. We concluded that effluent is viable for microalgae growth, especially Chlorella vulgaris, at the same time that the eutrophication potential and coliforms are decreased, contributing for better quality of the final effluent.

  15. Epilithic diatoms in headwater areas of the hydrographical sub-basin of the Andreas Stream, RS, Brazil, and their relation with eutrophication processes

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    Carla Giselda Heinrich

    2014-12-01

    Full Text Available AIM: This research aimed to study the composition of epilithic diatom flora in headwater areas of the sub-basin of the Andreas stream, RS, Brazil, and their relation with eutrophication processes. METHODS: Quarterly excursions (March, June, September, December 2012 and Mach 2013 were performed in ten sampling points selected in the sub-basin, to collect samples for the identification and counting the organisms in the group of diatoms (Class Bacillariophyceae. RESULTS: The results indicated the occurrence of 243 taxa, distributed in 53 genera. Of these, 59 were considered abundant, being distributed in 29 genera. Seven species showed elevated tolerance levels to organic pollution and eutrophication: Adlafia drouetiana (R. M. Patrick Metzeltin & Lange-Bertalot, Amphipleura lindheimeri Grunow; Fallacia monoculata (Hustedt D. G. Mann, Navicula cryptotenella Lange-Bertalot, Navicula symmetrica R. M. Patrick, Nitzschia palea (Kützing W. Smith and Sellaphora auldreekie D. G. Mann & S. M. McDonald in Mann et al. CONCLUSION: Although this research has been conducted in headwater areas, the occurrence of these seven species could be explained by considering the use of these areas for agricultural and livestock purposes, compromising the stability of these aquatic ecosystems, due to the significant contribution of fertilizer and organic matter, a condition that characterizes a process of eutrophication.

  16. Spatial distribution of plankton in Riau islands province, Indonesia

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    Ayu, I. P.; Pratiwi, N. T. M.; Iswantari, A.; Hariyadi, S.; Mulyawati, D.; Subhan, B.; Arafat, D.; Santoso, P.; Sastria, M.

    2017-01-01

    Riau Islands which is located at 4ºLU - 1ºLS and 104ºBT - 107ºBT, consist of around 3200 islands. It has high marine biodiversity, especially micro-plankton. Biodiversity of marine phytoplankton is usually dominated by diatom and zooplankton by micro-crustacean and early stage of marine biota. Nowadays, biodiversity of micro-plankton is an important study to identify their origin and potential as alien and invasive species. The aim of this research was to determine the biodiversity of marine micro-plankton in Riau Islands. This research was conducted in 14 small islands (Karanggerih, Pemping, Panjang, Melur, Palantuah, Dendun, Mantang, Bunut, Kelong, Mercusuar, Tokong Hiu Kecil, Tokong Hiu Besar, Karimun, Penyengat) in Riau Islands Province. Samples of micro-plankton were collected from surface water using plankton net. Samples were observed under light microscope and identified morphologically. Biodiversity index was calculated. There were found 20-34 taxa of phytoplankton and 10-17 taxa of zooplankton in all sites. Phytoplankton was dominated by Bacillariophyceae group and zooplankton by Crustacean and Protozoa groups. This result is expected for biodiversity bank information and further research.

  17. STRUKTUR KOMUNITAS PLANKTON DAN KONDISI LINGKUNGAN PERAIRAN DI TELUK JAKARTA

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    Adriani Sri Nastiti

    2016-03-01

    Full Text Available Fitoplankton dan zooplankton merupakan pakan alami bagi biota laut termasuk ikan. Tujuan penelitian adalah mengetahui struktur komunitas fitoplankton dan zooplankton serta kondisi lingkungan perairan di Teluk Jakarta. Penelitian dilakukan pada bulan April, Juni, Agustus dan Oktober 2009, pengamatan di 5 stasiun TJ1, TJ2, TJ3, TJ4 dan TJ5. Parameter yang di ukur adalah: kelimpahan fitoplankton dan zooplankton, suhu air, kecerahan, oksigen terlarut, pH, salinitas,. Hasil penelitian menunjukkan bahwa fitoplankton yang ditemukan 5 kelas meliputi: Cyanophyceae (6 spesies, Chlorophyceae (4 spesies, Bacillariophyceae (37 spesies, Dinophyceae (14 spesies dan Euglenophyceae (1 species. Zooplankton yang ditemukan 10 kelas meliputi : Crustacea (16 spesies, Holothuroidea (3 spesies, Ciliata (5 spesies, Sagittoidea (2 spesies, Sarcodina (3 spesies, Rotatoria (4 spesies, Echinodermata (1 spesies, Polychaeta (1 spesies, Urochordata (1 spesies dan Hydrozoa (1 spesies. Kelimpahan fitoplankton berkisar antara 1.587.086 - 3.799.799 sel/l. Kelimpahan zooplankton berkisar antara 922.010 - 3.834.261ind/l. Indeks keanekaragaman (=H  fitoplankton berkisar antara 1,74 – 3,64;indeks dominansi (=D berkisar antara 0,04-0,40 dan indeks keseragaman (=E berkisar antara 0,08-0,34. Indeks  biologi zooplankton menunjukkan nilai (=H berkisar antara 0,22-3,70; nilai  (=D berkisar antara 0,18-0,79; dan nilai (=E berkisar antara 0,01-0,37.  Suhu air berkisar  antara 29,5-31,6oC, pH berkisar antara 4,96-7,38 dan salinitas berkisar antara 12,0-31,5 o/oo. Teluk Jakarta diindikasikan mengalami tekanan lingkungan sehingga hanya beberapa spesies plankton mampu beradaptasi, yaitu dari kelas Bacillariophyceae (Chaetoceros sp dan Crustaceae (Calanus sp dan Acartia sp.  Phytoplankton and zooplankton is a natural food for other marine life including fish. Growth and development are supported by condition of aquatic environment. The research objective was to determine the community

  18. Seasonal Distribution of Phytoplankton in Riwada Reservoir, Visakhapatnam, Andhra Pradesh, India

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    Jyothi KAPARAPU

    2013-08-01

    Full Text Available The present study deals with seasonal variations, correlation coefficient and biodiversity indices of phytoplankton during April 2011 to March 2012 in the Riwada reservoir, Visakhapatnam, Andhra Pradesh, India. Sampling was performed at five stations during pre-monsoon, monsoon and post monsoon. There were a total of 57 genera belonging to four major groups i.e., Chlorophyceae (27 genera, Bacillariophyceae (14 genera, Cyanophyceae (13 genera and Euglenophyceae (three genera. Maximum and minimum total phytoplankton population and percentages were recorded at station three in pre monsoon and at station two during monsoon. The maximum and minimum species richness (Menhinick index R2 were found to be 1.29 at station one and 1.10 at station three respectively. Maximum and minimum species diversity (H1 were found at station four (3.98 and station two (3.71. Maximum species evenness was recorded at stations one, being four and five; minimum species evenness was recorded at station two. Correlation coefficient matrix indicated significant positive relationship with water temperature, pH, transparency, biological oxygen demand and chlorides, negative relationship with electric conductivity, total solids, total dissolved solids, total hardness, dissolved oxygen, nitrates, sulphates and phosphates of water. The diversity indices showed that the reservoir have a well balanced phytoplankton community.

  19. Effect of Chemical and Physical Properties of River Water in Shatt Al-Hilla on Phytoplankton Communities

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    Fikrat M. Hassan

    2008-01-01

    Full Text Available This paper aims to study the chemical and physical properties in the ecological system of Shatt Al-Hilla in Babylon Governorate in Iraq and its effect on phytoplankton population. In this context, several limnological parameters were evaluated during the period from December 2003 through November 2004 from four sampling stations sited along Shatt Al-Hilla. The physical parameters included: temperature, turbidity and electrical conductivity. The chemical parameters included: pH, alkalinity dissolved oxygen, total hardness and the concentrations of nitrite, nitrate, phosphate and sulphate. A total of 154 species were recorded. Ninety-seven species of the total belong to Bacillariophyceae, 37 species belong to Chlorophyceae, 13 species to Cyanophyceae, 5 species to Chrysophyceae, and 2 species to Euglenophyceae. Bimodal variation of phytoplankton was observed. Five genus of phytoplankton were the highest number of species ( Nitzschia, Navicula, Gomphonema, Cymbella and Scendesmus. Some species was occurred continuously during study period such as, Cyclotella ocellata, Cyclotella meneghiniana, Aulacoseria distans, and Gomphonema abbreviatum. The phytoplankton communities at all sampling sites showed a clear seasonal variation in phytoplankton cell number. However, no significant correlation between total cell number of phytoplankton and nutrient concentration was observed. The study was revealed the city sewage discharge, agriculture and urban run-off were affecting the water quality of Shatt Al-Hilla.

  20. Phytoplankton succession in a tropical freshwater lake, Bhoj Wetland (Bhopal, India): spatial and temporal perspective.

    Science.gov (United States)

    Ahmed, Ayaz; Wanganeo, Ashwani

    2015-04-01

    Bhoj Wetland is tropical freshwater system in central India "Bhopal" serving the citizens as one of the major source of water since its inception. Understanding the process of phytoplankton variation can be particularly useful in water quality improvement and management decision. In this study, phytoplankton taxonomic composition, temporal and spatial distribution, and diversity along with limnological abiotic characteristics were studied based on monthly sampling from four sampling stations (between May 2005 and April 2006). A total of 4 classes, 68 genera, and 98 species which belong to Chlorophyceae (52 species), Cyanobacteria (24 species), Bacillariophyceae (19 species), and Euglenophyceae (3 species), respectively, were identified. Phytoplankton assemblages were dominated by Cyanobacteria during summer months and were the most abundant. On an annual average scale, the phytoplankton density varied between 0.24×10(4) units/l at station 4 to 0.46×10(4) units/l at station 2, and station 2 represented highest population density. The predominant indices of the most predominant species varied between 0.03 and 0.26. Among physicochemical variables, temperature and total dissolved solids played a key role in phytoplankton growth as represented by statistical linear regression drawn between temperature, total dissolved solids, nitrate, and phytoplankton with R2 values of 0.6, 0.46, and 0.5, respectively.

  1. Phytoplankton community dynamics in an intermittently open hypereutrophic coastal lagoon in southern Portugal

    Science.gov (United States)

    Coelho, Susana; Pérez-Ruzafa, Angel; Gamito, Sofia

    2015-12-01

    Phytoplankton community' dynamics were studied in Salgados coastal lagoon in order to evaluate the effects of excessive organic loads and also physical stress caused by the irregular opening of the lagoon. Salgados is a hypereutrophic intermittently open coastal lagoon, which received freshwater inputs from small rivers and from a wastewater treatment plant. Cyanophyceae dominated the phytoplankton communities most of the time; Bacillariophyceae became the main taxonomic group in winter when the lagoon was closed; Chlorophyceae was the major class in early summer; pico-nano flagellate algae accounted for a high percentage of total phytoplankton during spring. Potentially harmful taxa were observed during most of the sampling periods, forming blooms and accounting for a considerable percentage of total phytoplankton abundance. A strong differentiation among dry and wet seasons could be noticed. The dry season was dominated by Microsystis aeruginosa, Rhodomonas sp., pico-nano flagellate algae, Cyclotella spp. and Planktothrix sp., while the wet season, although still with the presence of Microsystis aeruginosa, was dominated by Dolichospermum spiroides. The best environmental variables explaining stations patterns and based on phytoplankton taxa were days of isolation, pH, and salinity. Temperature, cumulative rain and total phosphorus were also related with species and stations patterns. The high nutrient load in Salgados lagoon promoted the development and persistence of harmful algae blooms. Proper management of coastal lagoons involves not only the control of direct discharges of nutrients, but also of other factors, including water level and communication with the sea.

  2. Richness of Phytoplankton and Zooplankton in Water Streams at Jobolarangan Forest

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    WIRYANTO

    2001-07-01

    Full Text Available Plankton is components of aquatic ecosystem. Phytoplankton play as primary producers, zooplankton play an important role in the higher order in the transfer of energy primary producers, the alga, to the higher order consumers such as aquatic insects, larval fish, and some adult fish. Streams of Jobolarangan forest may show phytoplankton and zooplankton that unique. The objectives of this research were to know diversity of phytoplankton and zooplankton and to determined their density. Plankton were sampled using 25-30 m mesh net, in three location of streams, i.e.: Parkiran (1773 m asl., Mrutu (1875 m asl., and Air Terjun (1600 m asl.. Samples were examined under light microscope for identification, and determined their density/L. Richness of phytoplankton in streams at Jobolarangan forest composed by family of Chlorophyceae, Euglenophyceae (Algae, and Bacillariophyceae. Zooplanktons that were found order of rotifer, cladoceras, and copepods. Allochtonous productivity, low nutrient level, low light level, and flowing water condition caused density of plankton/L in stream at Jobolarangan was low, i.e. 0,064 to 0,232.

  3. Factors affecting diatom dynamics in the alpine lakes of Colbricon (Northern Italy: a 10-year survey

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    Andrea SQUARTINI

    2010-08-01

    Full Text Available Planktonic diatom fluctuations, their diversity and relationships with environmental variables were analyzed for ten consecutive years in Colbricon Superiore and Inferiore, two small high-mountain lakes located in the Paneveggio-Pale di S. Martino Natural Park (Trento, Italy offering the rare opportunity to study two lakes differing only by area and volume and being in this respect in a ratio of 2:1 and 3:1 respectively. The lakes were monitored and sampled monthly, during ten ice-free periods, from 1998 to 2007, to correlate water chemical and physical characteristics with the recorded diversity and abundance of planktonic diatoms. 55 taxa of Bacillariophyceae were found, among which Cyclotella spp., Tabellaria flocculosa and Fragilaria spp. were dominant. Both chemical data and diatom community composition are consistent with well buffered mesotrophic lakes. We found statistical evidence that the development of diatoms was strongly related to the variation of water temperature. Furthermore, several different signatures of the diatom-enviroment relationships arose between the two lakes as e.g., a negative correlation between diatom development and water transparency was occurring in the larger lake only. As a result, the average diatom density recorded over the 10 years period were 1.17 fold higher than in the lower lake which corresponds to a 1.65 fold higher biomass. A size-dependent tighter response of the phytoplankton to chemical parameters appears to operate in the smaller waterbody compared to the larger one.

  4. A seasonal assessment of the impact of coal fly ash disposal on the River Yamuha, Delhi. II. Biology

    Energy Technology Data Exchange (ETDEWEB)

    Walia, A.; Mehra, N.K. [University of Delhi, Delhi (India). Dept. of Zoology

    1998-04-01

    The impact of fly ash on the biology of the Yamuna River, Delhi, was studied. Effluent come from a 200 MW capacity I.P. thermal power station. Seasonal variations in biological features in the non-impacted (Y-1) and the impacted (Y-2) segments of the river receiving fly ash effluents were studied. 60 genera of phytoplankton including 29 Chlorophyceae, 19 Bacillariophyceae, 8 Cyanobacteria, and 4 Egulenophyceae were recorded. Phytoplankton diversity was reduced at the impacted site in comparison to the non-impacted site of the river and substantial changes in the composition of various groups inhabiting these areas were observed. Zooplankton were also reduced at Y-2 compared to Y-1, especially rotifers and protozoans, while copepods and nauplii larvae were not affected to the same degree. Species diversity was not significantly different at Y-2 and Y-1 but similarity index varied from low to high between the two stations. Thus, not only was the density, number of genera and diversity reduced, even the generic composition of the plankton was markedly affected in the impacted waters. The observed perturbations could be due to sedimentation of ash particles, pH or elevated metal or salt concentration. A change in the concentration of one or more constituents disturbs the relationship between biota and could be the possible cause of reduced densities in the impacted waters. 56 refs., 10 figs., 4 tabs.

  5. Phytoplankton community dynamic detection from the chlorophyll-specific absorption coefficient in productive inland waters

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    Fernanda Sayuri Yoshino Watanabe

    2017-10-01

    Full Text Available Abstract Aim: In this research, we investigated the spectral variability of the specific phytoplankton absorption coefficient, a*φ, measured in a tropical meso-to-hypertrophic reservoir, aiming to find spectral features associated with the chlorophyll-a (chla and other accessory pigments present in different phytoplankton species. Methods To accomplish this research, two fieldworks were carried out in different seasons in order to report a high bio-optical variation. Phytoplankton absorption coefficient, aφ, and chla concentration were measured in laboratory to estimate a*φ. Results The outcomes have indicated that there is a remarkable phytoplankton community dynamic as spatially as seasonally. Chla absorption features were well-defined at 440 nm and 675 nm. Conclusions All the a*φ spectra exhibited the absorption peak around 630 nm associated with phycocyanin pigment present in cyanobacteria. Some spectra have shown a peak at about 460 nm, which is related to chlorophyll b and chlorophyll c (chlb and chlc, respectively found in different phytoplankton species. In turn, absorption features of carotenoids around 490 nm also were identified, however, well defined just in curves measured in austral autumn. Such spectral features are found in phytoplankton groups already identified in the study area such as Chlorophyceae, Bacillariophyceae, Cyanophyceae, Conjugatophyceae, Chrysophyceae, among others. We expect that the results are useful in researches about remote sensing of phytoplankton and eutrophication in reservoirs.

  6. Evaluation of a recirculating pond system for rearing juvenile freshwater mussels at White Sulphur Springs National Fish Hatchery, West Virginia, U.S.A.

    Science.gov (United States)

    Mummert, A.; Newcomb, T.J.; Neves, R.J.; Parker, B.

    2006-01-01

    A recirculating double-pond system at White Sulphur Springs National Fish Hatchery in West Virginia, U.S.A., was evaluated for suitability for culturing juvenile freshwater mussels. Newly metamorphosed juveniles of Villosa iris and Lampsilis fasciola were placed in the system, and their growth and survival were evaluated for 94 days. Throughout the study, parameters of water quality remained within ranges suitable for mussel survival. Planktonic algal densities in the pond system ranged from 2850 to 6892 cells/ml. Thirty-seven algal taxa were identified, primarily green algae (Chlorophyta), diatoms (Bacillariophyceae), and blue-green algae (Cyanoprokaryota). Over the culture period, juveniles of L. fasciola experienced significantly lower (p rate of L. fasciola may indicate a failure of the flow-through pond environment to meet its habitat requirements or that variable microhabitat conditions within culture containers existed. Growth did not differ significantly between the species (p = 0.13). Survival of V. iris and growth of both species were similar to previous trials to culture juvenile mussels. Survival rates as high as 66.4% at 93 days for V. iris suggest that juveniles of some riverine species can be successfully cultured in a recirculating pond environment.

  7. Regulation and function of xanthophyll cycle-dependent photoprotection in algae.

    Science.gov (United States)

    Goss, Reimund; Jakob, Torsten

    2010-11-01

    The xanthophyll cycle represents one of the important photoprotection mechanisms in plant cells. In the present review, we summarize current knowledge about the violaxanthin cycle of vascular plants, green and brown algae, and the diadinoxanthin cycle of the algal classes Bacillariophyceae, Xanthophyceae, Haptophyceae, and Dinophyceae. We address the biochemistry of the xanthophyll cycle enzymes with a special focus on protein structure, co-substrate requirements and regulation of enzyme activity. We present recent ideas regarding the structural basis of xanthophyll cycle-dependent photoprotection, including different models for the mechanism of non-photochemical quenching of chlorophyll a fluorescence. In a dedicated chapter, we also describe the unique violaxanthin antheraxanthin cycle of the Prasinophyceae, together with its implication for the mechanism of xanthophyll cycle-dependent heat dissipation. The interaction between the diadinoxanthin cycle and alternative electron flow pathways in the chloroplasts of diatoms is an additional topic of this review, and in the last chapter we cover aspects of the importance of xanthophyll cycle-dependent photoprotection for different algal species in their natural environments.

  8. Ecological studies on Al-Khadoud Spring, Al-Hassa, Saudi Arabia.

    Science.gov (United States)

    Al-Kahtani, Mohammed A; Youssef, Ashraf M; Fathi, Adel A

    2007-11-15

    Al-Khadoud spring is one of the most important water resources in Al-Hassa Governorate, Saudi Arabia. However, much of its biotic information is still unknown. This study presented preliminary ecological information of this aquatic body. Regarding to macrophytes, a total of eight species were observed along the study sites. These species include two submerged aquatic plants (Potamogeton pectinatus L. and Ceratophyllum demersum L.). The common distributed species are Phragmites australis (Cav.) Trimex Steud and Cyperus rotundus (L.). On the other hand, a total of 20 algal genera were recorded with 7 genera of Chlorophyceae, 8 of Bacillariophyceae, 4 of Cyanophyceae and one of Euglenophyceae. The common phytoplankton occurred in all three investigated sites were Chlorella vulgaris, Mougeotia sp., Oscillatoria sp. and Actinastrum sp. Regarding to the biotic fauna, different forms of unicellular zooplankton such as Paramecium and Amoeba were recorded. Invertebrates such as freshwater insects and some freshwater snails were documented in the study sites including Melanodies tuberculata, Melanopsis praemorsa and Lymnaea auricularia. As regard to vertebrates, one species of fish, Aphanius dispar, dominate the spring basin and its extended channels.

  9. Biofilm scrubbing for restoration—algae community composition and succession in artificial streams

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    Magdalena Mayr

    2016-09-01

    Full Text Available Photoautotrophic biofilms play a pivotal role in self-purification of rivers. We took advantage of the biofilm’s cleaning capacity by applying artificial stream mesocosms, called algae turf scrubberTM (ATS, to reduce the nutrient load of a highly eutrophicated backwater in Vienna (Austria. Since purification strongly depends on benthic algae on the ATS, we focused on the algae community composition and succession. Estimation of coverage, photographic documentation for micromapping, species identification and pigment analyses were carried out. Already one week after exposition, 20–30 different taxa were recorded, suggesting a rapid colonization of the substrate. In total around 200 taxa were identified, mainly belonging to Chlorophyta, Bacillariophyceae and Cyanoprokaryota. Nonmetric multidimensional scaling implied that season and succession strongly influenced species composition on the ATS and a minimum turnover of 0.28 indicates a development towards a more stable community at the end of experiments. We measured maximum biomass production of ~250 g m−2 in June and August and during a period of 5 months nearly 19 kg ha−1 phosphorus could be removed. ATS systems proved to retain nutrients and produce algae biomass in an environmentally friendly and cost effective way and thus support restoration of highly eutrophicated water bodies.

  10. Harmful Algal in Banyuasin Coastal Waters, South Sumatera

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    Riris Aryawati

    2016-09-01

    Full Text Available Phytoplankton have important as food-chain major component and primary production of marine environment. However, high abundance of phytoplankton could give harmful effects toward water ecosystem. Moreover, they could produce toxic substances that will be accumulated within their consumer. This accumulation could be dangerous for human or animals.This research were aimed to determine and calculatespecies of harmful algae in Banyuasin coastal waters. The study was conducted on April, June, August, October and December of 2013, and in February 2014, at ten stations. Phytoplankton samples were taken vertically using plankton nets. In the form of cone-shaped with a diameter of 30 cm, length 100 cm and mesh size 30 μm.The result showed that there are 35 genera of phytoplankton. That have been found and consisted of four groups; Bacillariophyceae, Dinophyceae, Cyanophyceae and Chlorophyceae. 13 species were identified as Harmful Algal (Chaetoceros, Coscinodiscus, Nitzschia, Skeletonema, Thalassiosira, Alexandrium, Ceratium, Dinophysis, Noctiluca, Protoperidinium, Prorocentrum, Anabaena dan Oscillatoria, with seven of them were known for having toxin (Nitzschia, Alexandrium, Dinophysis, Protoperidinium Prorocentrum, Anabaena and Oscillatoria. Monitoring result showed that the highest number of species of potential harmful algal blooms (HABs occured in June and the highest abundance occured in August, especially Chaetoceros and Skeletonema.How to CiteAryawati, R., Bengen, D. G., Prartono, T., & Zulkifli, H. (2016. Harmful Algal in Banyuasin Coastal Waters, South Sumatera. Biosaintifika: Journal of Biology & Biology Education, 8(2, 231-239.

  11. An ecological and floristic study of the diatoms in Babolrud river

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    Naser Jafari

    2014-03-01

    Full Text Available Epilithic diatoms are a division of Bacillariophyceae which live on stone and hard surfaces. This study was aimed to investigate the population dynamics of diatoms in Babolrud river. Samples were collected from 5 stations from May 2012 through September 2012 in a monthly interval. Temperature, pH, NO3-, PO4- and (EC were measured for each sampling. Samples were prepared using Patrick and Reimer procedure. 72 taxa were identified, among which 33 taxa (46% were cosmopolitan or widely distributed. The genera with the highest species were Navicula (12, Nitzschia (9, Achnanthes (9, Cymbella (8 and Gomphonema (6. The decrease in diatoms diversity from upstream toward downstream can be regarded as an indicator of increasing water pollution. Trends in distribution of diatom species in the sampling sites were explained by variations in environmental parameters such as conductivity, pH, temperature, nitrate and phosphate. In highly contaminated sites of the Babolrud River, species such as Gomphonema olivaceum, Navicula pupula, Nitzschia flexa and Pinnularia major were observed, while individuals of Achnanthes clevei, Achnanthes deflexa, Cymbella affinis and Fragilaria virescens were found in sampling sites with relatively less environmental perturbation. We concluded that diatoms can be used as quantitative indicators of environmental conditions in lotic systems.

  12. Contrasting Strategies of Photosynthetic Energy Utilization Drive Lifestyle Strategies in Ecologically Important Picoeukaryotes

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    Kimberly H. Halsey

    2014-04-01

    Full Text Available The efficiency with which absorbed light is converted to net growth is a key property for estimating global carbon production. We previously showed that, despite considerable evolutionary distance, Dunaliella tertiolecta (Chlorophyceae and Thalassiosira weissflogii (Bacillariophyceae share a common strategy of photosynthetic energy utilization and nearly identical light energy conversion efficiencies. These findings suggested that a single model might be appropriate for describing relationships between measures of phytoplankton production. This conclusion was further evaluated for Ostreococcus tauri RCC1558 and Micromonas pusilla RCC299 (Chlorophyta, Prasinophyceae, two picoeukaryotes with contrasting geographic distributions and swimming abilities. Nutrient-dependent photosynthetic efficiencies in O. tauri were similar to the previously studied larger algae. Specifically, absorption-normalized gross oxygen and carbon production and net carbon production were independent of nutrient limited growth rate. In contrast, all measures of photosynthetic efficiency were strongly dependent on nutrient availability in M. pusilla. This marked difference was accompanied by a diminished relationship between Chla:C and nutrient limited growth rate and a remarkably greater efficiency of gross-to-net energy conversion than the other organisms studied. These results suggest that the cost-benefit of decoupling pigment concentration from nutrient availability enables motile organisms to rapidly exploit more frequent encounters with micro-scale nutrient patches in open ocean environments.

  13. Effects of Silicon-Limitation on Growth and Morphology of Triparma laevis NIES-2565 (Parmales, Heterokontophyta)

    Science.gov (United States)

    Yamada, Kazumasa; Yoshikawa, Shinya; Ichinomiya, Mutsuo; Kuwata, Akira; Kamiya, Mitsunobu; Ohki, Kaori

    2014-01-01

    The order Parmales (Heterokontophyta) is a group of small-sized unicellular marine phytoplankton, which is distributed widely from tropical to polar waters. The cells of Parmales are surrounded by a distinctive cell wall, which consists of several siliceous plates fitting edge to edge. Phylogenetic and morphological analyses suggest that Parmales is one of the key organisms for elucidating the evolutionary origin of Bacillariophyceae (diatoms), the most successful heterokontophyta. The effects of silicon-limitation on growth and morphogenesis of plates were studied using a strain of Triparma laevis NIES-2565, which was cultured for the first time in artificial sea water. The cells of T. laevis were surrounded by eight plates when grown with sufficient silicon. However, plate formation became incomplete when cells were cultured in a medium containing low silicate (ca. silicon-limitation did not affect growth rate; cells continued to divide without changing their growth rate, even after all plates were lost. Loss of plates was reversible; when cells without plates were transferred to a medium containing sufficient silicate, regeneration of shield and ventral plates was followed by the formation of girdle and triradiate plates. The results indicate that the response to silicon-limitation of T. laevis is different from that of diatoms, where cell division becomes inhibited under such conditions. PMID:25054645

  14. Microbial planktonic communities in the Red Sea: high levels of spatial and temporal variability shaped by nutrient availability and turbulence

    KAUST Repository

    Pearman, John K.

    2017-07-20

    The semi-enclosed nature of the Red Sea (20.2°N-38.5°N) makes it a natural laboratory to study the influence of environmental gradients on microbial communities. This study investigates the composition and structure of microbial prokaryotes and eukaryotes using molecular methods, targeting ribosomal RNA genes across different regions and seasons. The interaction between spatial and temporal scales results in different scenarios of turbulence and nutrient conditions allowing for testing of ecological theory that categorizes the response of the plankton community to these variations. The prokaryotic reads are mainly comprised of Cyanobacteria and Proteobacteria (Alpha and Gamma), with eukaryotic reads dominated by Dinophyceae and Syndiniophyceae. Periodic increases in the proportion of Mamiellophyceae and Bacillariophyceae reads were associated with alterations in the physical oceanography leading to nutrient increases either through the influx of Gulf of Aden Intermediate Water (south in the fall) or through water column mixing processes (north in the spring). We observed that in general dissimilarity amongst microbial communities increased when nutrient concentrations were higher, whereas richness (observed OTUs) was higher in scenarios of higher turbulence. Maximum abundance models showed the differential responses of dominant taxa to temperature giving an indication how taxa will respond as waters become warmer and more oligotrophic.

  15. Environmental gradients regulate the spatio-temporal variability of phytoplankton assemblages in the Can Gio Mangrove Biosphere Reserve, Vietnam

    Science.gov (United States)

    Pham, Thanh-Luu

    2017-07-01

    This paper covers spatial and temporal variation in phytoplankton communities and physico-chemical variables in the Can Gio Mangrove Biosphere Reserve (CGMBR), Vietnam, based on field measurement conducted monthly at nine stations during February 2009 to January 2010. Species diversity, richness and phytoplankton abundance were calculated. Canonical Correspondence Analysis (CCA) was used to investigate the relationship between environmental factors and phytoplankton community. A total of 126 species were recorded with a clear dominance of Bacillariophyceae, which formed about 76.4% of the total phytoplankton counts with an annual average of 44.900 cells/L. Other algal classes like Dinophyceae, Cyanophyceae and Chrysophyceae sustained low counts, forming collectively about 14% of the total abundance of phytoplankton. Although Chaetoceros and Coscinodiscus were the most dominant genera, Schroederella and Skeletonema showed high abundance during the studied period. Among the nine environmental parameters tested in this study, salinity, nitrate and ammonium were found to be significantly different between two seasons. On the other hand, no significant difference was found between stations for the studied variables. Results of CCA indicated that phytoplankton assemblage in the CGMBR was influenced by salinity, nitrate and phosphate concentration. This is the first study simultaneously investigating the phytoplankton communities and their environment in this area and it is essential in order to set up the baseline of future studies.

  16. Carotenoids, Phenolic Compounds and Tocopherols Contribute to the Antioxidative Properties of Some Microalgae Species Grown on Industrial Wastewater

    Science.gov (United States)

    Safafar, Hamed; van Wagenen, Jonathan; Møller, Per; Jacobsen, Charlotte

    2015-01-01

    This study aimed at investigating the potential of microalgae species grown on industrial waste water as a new source of natural antioxidants. Six microalgae from different classes, including Phaeodactylum sp. (Bacillariophyceae), Nannochloropsis sp. (Eustigmatophyceae), Chlorella sp., Dunaniella sp., and Desmodesmus sp. (Chlorophyta), were screened for their antioxidant properties using different in vitro assays. Natural antioxidants, including pigments, phenolics, and tocopherols, were measured in methanolic extracts of microalgae biomass. Highest and lowest concentrations of pigments, phenolic compounds, and tocopherols were found in Desmodesmus sp. and Phaeodactylum tricornuotom microalgae species, respectively. The results of each assay were correlated to the content of natural antioxidants in microalgae biomass. Phenolic compounds were found as major contributors to the antioxidant activity in all antioxidant tests while carotenoids were found to contribute to the 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity, ferrous reduction power (FRAP), and ABTS-radical scavenging capacity activity. Desmodesmus sp. biomass represented a potentially rich source of natural antioxidants, such as carotenoids (lutein), tocopherols, and phenolic compounds when cultivated on industrial waste water as the main nutrient source. PMID:26690454

  17. Proximate Content of “Klekap” (Microphytobenthos and Their Associated Meiofauna) from Milk-Fish Pond

    Science.gov (United States)

    Widianingsih; Zainuri, Muhammad; Anggoro, Sutrisno; Pancasakti Kusumaningrum, Hermin

    2017-02-01

    Microphytobentos and their associated mieofauna (‘klekap”) have important role in milkfish pond ecosystem expecially traditional fish pond. Microphytobenthos and their associated meiofauna not only consists of unicellular microalgae from class Bacillariophyceae, Cyanophyceae, Chlorophyceae but also a lot of meiofauna such as Nematoda, Annelida, Mollusc, Arthropoda, etc. Microphytobenthos and their associated meiofauna inhabit in the upper most surface sediment layer. They also have important role in the primary and secondary productivity. This research has purpose to investigate the composition of proximate in the microphytobenthos and their associated meiofauna. Microphytobenthos and their associated meiofauna were taken from three milkfish ponds in Pati area, Central of Jawa, Indonesia. Samples were taken directly by hand core from 3 stations with 3 replications. The research result showed that the value of protein content had range 6.9±0.33 - 7.73±0.37 %-dw, the value of carbohydrate content had range 10.44±1.2 - 12.59±0.15 %-dw, the value of lipid content had range 0.86±0.07 - 0.96±0.07 %-dw. It concluded that the third station has higher value of protein, lipid and carbohydrate compared than the first and the second station.

  18. Nutrients and Phytoplankton in a Shallow, Hypereutrophic Urban Lake: Prospects for Restoration

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    Brianne Norris

    2017-06-01

    Full Text Available University Lake, a shallow, artificial, urban lake adjacent to the campus of Louisiana State University, has a long history of water quality problems, including algal blooms, fish kills, and high concentrations of fecal indicator bacteria. Periodic dredging of the lake is necessary to prevent its return to swampland. This study was undertaken to elucidate the roles of allochthonous versus autochthonous nutrients as causes of water quality problems in the lake, with the expectation that this information would help identify strategies for lake restoration. Photosynthetic rates and concentrations of inorganic nutrients and phytoplankton pigments were measured over a period of one year. More than 90% of the chlorophyll a (chl a in the lake was accounted for by Chlorophyceae, Cyanophyceae, and Bacillariophyceae. Concentrations of chl a, which averaged 75 μg L−1, fluctuated weekly during dry weather by as much as a factor of four. Phytoplankton growth rates were about 30% higher 1–2 days after rain events than after periods of dry weather, the implication being that allochthonous nutrient loading has a significant effect on the dynamics of the phytoplankton community in the lake. Therefore, dredging of sediments will likely produce no long-term improvement in water quality. More than 100 storm drains currently discharge into the lake, and diversion of those drains may be the most cost-effective strategy for effecting a long-term improvement in water quality.

  19. Microalgae population dynamics in photobioreactors with secondary sewage effluent as culture medium

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    Marchello, Adriano E.; Lombardi, Ana T.; Dellamano-Oliveira, Maria José; de Souza, Clovis W.O.

    2015-01-01

    Nitrogen and phosphorus present in sewage can be used for microalgae growth, possibiliting cost reduction in the production of microalgae at the same time that it decreases the eutrophication potential of the effluent. This research aimed at monitoring the native community of microalgae and coliform bacteria in a secondary effluent from anaerobic municipal sewage treatment. Two treatments (aerated and non-aerated) were performed to grow microalgae under semi-controlled conditions in semi-closed photobioreactors in a greenhouse. The results showed no significant pH and coliforms (total and Escherichia coli ) variation between treatments. Nutrient concentrations were reduced supporting microalgae growth up to 10 7 cells.mL −1 independent of aeration. Exponential growth was obtained from the first day for the non-aerated, but a 5 day lag phase of growth was obtained for the aerated. Chlorella vulgaris was the dominant microalgae (99.9%) in both treatments. In the aerated, 5 algae classes were detected (Chlorophyceae, Cyanophyceae, Chrysophyceae, Bacillariophyceae and Euglenophyceae), with 12 taxa, whereas in the non-aerated, 2 classes were identified (Chlorophyceae and Cyanophyceae), with 5 taxa. We concluded that effluent is viable for microalgae growth, especially Chlorella vulgaris, at the same time that the eutrophication potential and coliforms are decreased, contributing for better quality of the final effluent. PMID:26221091

  20. Carotenoids, Phenolic Compounds and Tocopherols Contribute to the Antioxidative Properties of Some Microalgae Species Grown on Industrial Wastewater.

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    Safafar, Hamed; van Wagenen, Jonathan; Møller, Per; Jacobsen, Charlotte

    2015-12-11

    This study aimed at investigating the potential of microalgae species grown on industrial waste water as a new source of natural antioxidants. Six microalgae from different classes, including Phaeodactylum sp. (Bacillariophyceae), Nannochloropsis sp. (Eustigmatophyceae), Chlorella sp., Dunaniella sp., and Desmodesmus sp. (Chlorophyta), were screened for their antioxidant properties using different in vitro assays. Natural antioxidants, including pigments, phenolics, and tocopherols, were measured in methanolic extracts of microalgae biomass. Highest and lowest concentrations of pigments, phenolic compounds, and tocopherols were found in Desmodesmus sp. and Phaeodactylum tricornuotom microalgae species, respectively. The results of each assay were correlated to the content of natural antioxidants in microalgae biomass. Phenolic compounds were found as major contributors to the antioxidant activity in all antioxidant tests while carotenoids were found to contribute to the 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity, ferrous reduction power (FRAP), and ABTS-radical scavenging capacity activity. Desmodesmus sp. biomass represented a potentially rich source of natural antioxidants, such as carotenoids (lutein), tocopherols, and phenolic compounds when cultivated on industrial waste water as the main nutrient source.

  1. Microalgae population dynamics in photobioreactors with secondary sewage effluent as culture medium.

    Science.gov (United States)

    Marchello, Adriano E; Lombardi, Ana T; Dellamano-Oliveira, Maria José; de Souza, Clovis W O

    2015-03-01

    Nitrogen and phosphorus present in sewage can be used for microalgae growth, possibiliting cost reduction in the production of microalgae at the same time that it decreases the eutrophication potential of the effluent. This research aimed at monitoring the native community of microalgae and coliform bacteria in a secondary effluent from anaerobic municipal sewage treatment. Two treatments (aerated and non-aerated) were performed to grow microalgae under semi-controlled conditions in semi-closed photobioreactors in a greenhouse. The results showed no significant pH and coliforms (total and Escherichia coli ) variation between treatments. Nutrient concentrations were reduced supporting microalgae growth up to 10 (7) cells.mL (-1) independent of aeration. Exponential growth was obtained from the first day for the non-aerated, but a 5 day lag phase of growth was obtained for the aerated. Chlorella vulgaris was the dominant microalgae (99.9%) in both treatments. In the aerated, 5 algae classes were detected (Chlorophyceae, Cyanophyceae, Chrysophyceae, Bacillariophyceae and Euglenophyceae), with 12 taxa, whereas in the non-aerated, 2 classes were identified (Chlorophyceae and Cyanophyceae), with 5 taxa. We concluded that effluent is viable for microalgae growth, especially Chlorella vulgaris, at the same time that the eutrophication potential and coliforms are decreased, contributing for better quality of the final effluent.

  2. Carotenoids, Phenolic Compounds and Tocopherols Contribute to the Antioxidative Properties of Some Microalgae Species Grown on Industrial Wastewater

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    Hamed Safafar

    2015-12-01

    Full Text Available This study aimed at investigating the potential of microalgae species grown on industrial waste water as a new source of natural antioxidants. Six microalgae from different classes, including Phaeodactylum sp. (Bacillariophyceae, Nannochloropsis sp. (Eustigmatophyceae, Chlorella sp., Dunaniella sp., and Desmodesmus sp. (Chlorophyta, were screened for their antioxidant properties using different in vitro assays. Natural antioxidants, including pigments, phenolics, and tocopherols, were measured in methanolic extracts of microalgae biomass. Highest and lowest concentrations of pigments, phenolic compounds, and tocopherols were found in Desmodesmus sp. and Phaeodactylum tricornuotom microalgae species, respectively. The results of each assay were correlated to the content of natural antioxidants in microalgae biomass. Phenolic compounds were found as major contributors to the antioxidant activity in all antioxidant tests while carotenoids were found to contribute to the 1,1-diphenyl-2-picryl-hydrazil (DPPH radical scavenging activity, ferrous reduction power (FRAP, and ABTS-radical scavenging capacity activity. Desmodesmus sp. biomass represented a potentially rich source of natural antioxidants, such as carotenoids (lutein, tocopherols, and phenolic compounds when cultivated on industrial waste water as the main nutrient source.

  3. A method of batch-purifying microalgae with multiple antibiotics at extremely high concentrations

    Science.gov (United States)

    Han, Jichang; Wang, Song; Zhang, Lin; Yang, Guanpin; Zhao, Lu; Pan, Kehou

    2016-01-01

    Axenic microalgal strains are highly valued in diverse microalgal studies and applications. Antibiotics, alone or in combination, are often used to avoid bacterial contamination during microalgal isolation and culture. In our preliminary trials, we found that many microalgae ceased growing in antibiotics at extremely high concentrations but could resume growth quickly when returned to an antibiotics-free liquid medium and formed colonies when spread on a solid medium. We developed a simple and highly efficient method of obtaining axenic microalgal cultures based on this observation. First, microalgal strains of different species or strains were treated with a mixture of ampicillin, gentamycin sulfate, kanamycin, neomycin and streptomycin (each at a concentration of 600 mg/L) for 3 days; they were then transferred to antibiotics-free medium for 5 days; and finally they were spread on solid f/2 media to allow algal colonies to form. With this method, five strains of Nannochloropsis sp. (Eustigmatophyceae), two strains of Cylindrotheca sp. (Bacillariophyceae), two strains of Tetraselmis sp. (Chlorodendrophyceae) and one strain of Amphikrikos sp. (Trebouxiophyceae) were purified successfully. The method shows promise for batch-purifying microalgal cultures.

  4. Influence of ecological filters on phytoplankton communities in semi-arid solar saltern environments

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    Raiane Santos Costa

    2015-03-01

    Full Text Available ObjectiveThis study analyzed the influence of ecological filters (abiotic variables on the phytoplankton community in hypersaline ecosystems.MethodsThe abiotic variables measured herein were: pH, water temperature, salinity, ammonium ion, total nitrogen, nitrite, nitrate, total phosphorus, and soluble reactive phosphorus. The phytoplankton community was studied for density, richness and Shannon-Wiener diversity index. Data were analyzed using analysis of variance, linear regression and Canonical correspondence analysis (CCA.ResultsIn total, 110 taxa were identified in 3 solar salterns, distributed into 9 taxonomic classes, with the predominance of Cyanobacteria (41.8% and Bacillariophyceae (22.7%. The species Pseudanabaena galeata was the only species sampled in all saline environments. Salinity significantly influenced the richness in the three salterns, Augusto Severo (F(1,22 = 23.2, p <0.001, Francisco Menescal (F(1,22 = 50.02, p <0.001 and Santa Clara (F(1,22 = 66.33, p <0.001. The first two CCA axes explained 41.6% of total data variability, with a negative relationship with soluble reactive phosphorus for axis 2.ConclusionThe study showed the influence of the dynamics of salterns ecosystems on the phytoplankton community structure. This is associated with filters developed by the environment, where the increasing salinity, temperature and precipitation of salts influence the composition of these organisms in the ecosystem.

  5. Species Diversity of Plankton in Suan Sunandha Rajabhat University, Samut Songkhram Campus

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    Noppadon Chamchoi

    2015-01-01

    Full Text Available The study of phytoplankton and zooplankton in Suan Sunandha Rajabhat University, Samut Songkram Campus by collecting the samples following the seasons: the cool season (December, 2012, the hot season (March, 2013 and the rainy season (June, 2013. The plankton samples were collected from 5 stations by using 70 micrometers mesh size of plankton net and examined the water quality. The results showed that, in total, there are plankton in 48 genera, 77 species which consist of 36 genera, 58 species of the phytoplankton, and 12 genera, 19 species of the zooplankton. The phytoplankton: Class Bacillariophyceae was the dominant group and the most diverse was the genus Chaetoceros (8 species. The zooplankton: Phylum Sarcomastigophora had the most species diversity and most diverse zooplankton was the genus Ceratium (5 species. The cool season was the season when the greatest species diversity of the plankton could be found and the water temperature average was 27.79 ° C. The pH average was 7.82. The dissolved oxygen average was 6.21 mg/l. The salinity average was 24 ppt. These conditions are the appropriate environment for these living aquatic organisms.

  6. Use of in vivo phycocyanin fluorescence to monitor potential microcystin-producing cyanobacterial biovolume in a drinking water source.

    Science.gov (United States)

    McQuaid, N; Zamyadi, A; Prévost, M; Bird, D F; Dorner, S

    2011-02-01

    The source water of a drinking water treatment plant prone to blooms, dominated by potential microcystin-producing cyanobacteria, was monitored for two seasons in 2007-2008. In the 2008 season, the median value for potential microcystin-producing cyanobacterial biovolume was 87% of the total phytoplankton biovolume in the untreated water of the plant. Depth profiles taken above the plant's intake identified three sampling days at high risk for the contamination of the plant's raw water with potentially toxic cyanobacteria. Chlorophyceae and Bacillariophyceae caused false positive values to be generated by the phycocyanin probe when cyanobacteria represented a small fraction of the total phytoplanktonic biovolume present. However, there was little interference with the phycocyanin probe readings by other algal species when potential microcystin-producing cyanobacteria dominated the phytoplankton of the plant's untreated water. A two-tiered method for source water monitoring, using in vivo phycocyanin fluorescence, is proposed based on (1) a significant relationship between in vivo phycocyanin fluorescence and cyanobacterial biovolume and (2) the calculated maximum potential microcystin concentration produced by dominant Microcystis sp. biovolume. This method monitors locally-generated threshold values for cyanobacterial biovolume and microcystin concentrations using in vivo phycocyanin fluorescence.

  7. Environmental gradients regulate the spatio-temporal variability of phytoplankton assemblages in the Can Gio Mangrove Biosphere Reserve, Vietnam

    Science.gov (United States)

    Pham, Thanh-Luu

    2017-12-01

    This paper covers spatial and temporal variation in phytoplankton communities and physico-chemical variables in the Can Gio Mangrove Biosphere Reserve (CGMBR), Vietnam, based on field measurement conducted monthly at nine stations during February 2009 to January 2010. Species diversity, richness and phytoplankton abundance were calculated. Canonical Correspondence Analysis (CCA) was used to investigate the relationship between environmental factors and phytoplankton community. A total of 126 species were recorded with a clear dominance of Bacillariophyceae, which formed about 76.4% of the total phytoplankton counts with an annual average of 44.900 cells/L. Other algal classes like Dinophyceae, Cyanophyceae and Chrysophyceae sustained low counts, forming collectively about 14% of the total abundance of phytoplankton. Although Chaetoceros and Coscinodiscus were the most dominant genera, Schroederella and Skeletonema showed high abundance during the studied period. Among the nine environmental parameters tested in this study, salinity, nitrate and ammonium were found to be significantly different between two seasons. On the other hand, no significant difference was found between stations for the studied variables. Results of CCA indicated that phytoplankton assemblage in the CGMBR was influenced by salinity, nitrate and phosphate concentration. This is the first study simultaneously investigating the phytoplankton communities and their environment in this area and it is essential in order to set up the baseline of future studies.

  8. Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

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    F. Siddika

    2012-06-01

    Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

  9. Response of phytoplankton to an experimental fish culture in net cages in a subtropical reservoir.

    Science.gov (United States)

    Bartozek, E C R; Bueno, N C; Feiden, A; Rodrigues, L C

    2016-01-01

    This study aimed to evaluate nutrients concentration and spatial-temporal changes in phytoplankton biovolume during an experimental fish culture in net cages in a lateral arm of Salto Caxias reservoir, Brazil. Two sampling stations were placed in the affected lateral arm and other two in a cageless lateral arm. Neither abiotic variables nor phytoplankton biovolume presented significant differences between the treatments. Only temporal changes were confirmed by the analysis performed. Both lateral arms were classified as oligotrophic, reflecting low influence of the net cages. Phytoplankton growth seems to be limited by nitrogen. Biovolume values were, in general, low and five major functional groups were recognized (E, F, G, K and P). In summer higher biovolume values were observed and representatives of Chlorophyceae and Cyanobacteria belonging to the functional groups F and K, respectively, were the most important. In winter phytoplankton was mainly composed by Bacillariophyceae taxa from P group. G group was also restricted to winter and E group occurred in winter and summer. The variations recorded in phytoplankton structure appear to have been mainly influenced by seasonal changes in temperature, precipitation and nutrients availability. The effects of net cages on the abiotic variables and phytoplankton biovolume appear to have been small, probably due to the small number of net cages employed and the system dilution capacity. However, a permanent monitoring of phytoplankton is recommended, since this environment has a carrying capacity, from which the trophic state may increase.

  10. Freshwater diatoms as a source of lipids for biofuels.

    Science.gov (United States)

    Graham, James M; Graham, Linda E; Zulkifly, Shahrizim B; Pfleger, Brian F; Hoover, Spencer W; Yoshitani, Jun

    2012-03-01

    Until recently, biodiesel production has been derived from terrestrial plants such as soybean and canola, leading to competition between biodiesel production and agricultural production for source materials. Microalgae have the potential to synthesize 30 times more oil per hectare than terrestrial plants without competing for agricultural land. We examined four genera (Cyclotella, Aulacoseira, Fragilaria, Synedra) of common freshwater diatoms (Bacillariophyceae) for growth and lipid content in defined medium (sD11) that replicates hypereutrophic conditions in lakes and wastewater treatment plant effluents and optimized the medium for silicon content. Cyclotella and Aulacoseira produced the highest levels of total lipids, 60 and 43 μg total lipids/ml, respectively. Both diatoms are rich in fatty acids C14, C16, C16:1, C16:2,7,10, and C22:5n3. Of the diatoms examined, Cyclotella reached the highest population density (>2.5 × 10(6) cells/ml) in stationary phase when many of the cells appeared to be filled entirely with oil. Silicon enrichment studies indicated that for optimal utilization of phosphorus and nitrogen by diatoms growing in wastewater effluent, the amount of silicon present or added to the effluent should be 17.5 times the mass of phosphorus in the effluent. With high growth rates, high lipid contents, and rapid settling rates, Cyclotella and Aulacoseira are candidates for biodiesel production.

  11. Potensi Fitoplankton sebagai Sumber Daya Pakan pada Pemeliharaan Larva Ikan Mas (Cyprinus carpio di BBPBAT Sukabumi

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    Ana Widiana

    2016-03-01

    Full Text Available The main problem encountered in producing larvae  is the larvae  that got low due to high mortality. One attempt to overcome this problem is the use of phytoplankton as natural feed. The purpose of this study is to determine phytoplankton community structure and potential as a resource phytoplankton feed on larval rearing carp. The research was conducted in April 2012. The results showed that the phytoplankton found in the larval rearing pond goldfish are Class Bacillariophyceae (1 genera, Chlorophyceae (13 genera, and Cyanophyceae (7 genera. Phytoplankton Chlorophyceae group is a group that has the highest abundance of larval rearing carp pond. Diversity index of phytoplankton in pond carp larvae ranged from 0.65 to 1.64 (Low Diversity. Based on the preponderance index carp larvae utilize phytoplankton as natural feed by selecting the class Chlorophyceae and Cyanophyceaea in early growth until the time nursery a preponderance index value respectively 87.76% and 12.23%.

  12. Phytoplankton community and limnology of Chatla floodplain wetland of Barak valley, Assam, North-East India

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    Sultana Laskar H.

    2013-09-01

    Full Text Available Phytoplankton diversity was investigated over a period of two years (2006 to 2008 in Chatla floodplain wetland in Barak valley, Assam, North-East India. Site 1 and site 2 are two inlets and site 3 is a lentic system associated with vegetation cover of Calamus tenuis and Baringtonia acutangula. The floodplain has a unique hydrology because of the presence of different types of habitats (inlets, fisheries, beels and outlets which maintains a network among the floodplains, rivers and streams. Phytoplankton community composition, density and diversity were studied in relation to environmental variables. All the variables were estimated by following standard methods. Phytoplankton was collected by plankton net and quantitative estimation was made by using Sedgwick Rafter counting cell. Phytoplankton community comprised 53 taxa represented by Chlorophyceae (31, Cyanophyceae (11, Bacillariophyceae (7, Euglenophyceae (1 and Dinophyceae (3. Phytoplankton taxa was dominated by Volvox sp., Nostoc sp., Eunotia sp., Navicula sp., Euglena spp. and density was found highest in site 3 and lowest in site 1. Shannon diversity index (H′ for phytoplankton community varied between 2.4 to 2.65 indicating fairly high species diversity. The varying magnitude of correlationship among environmental variables and phytoplankton species density as shown by Canonical correspondence analysis (CCA indicated that some of the environmental variables (water temperature, transparency, rainfall, nitrate and ammonia are the driving factors for governing the phytoplankton species assemblages in Chatla floodplain wetland. Fluctuation of phytoplankton density and community composition in different habitats indicated various niche apportionment as well as anthropogenic influences.

  13. Seasonal succession of phytoplankton community and its relationship with environmental factors of North Temperate Zone water of the Zhalong Wetland, in China.

    Science.gov (United States)

    Ma, Yun; Li, Guibai; Li, Jing; Zhou, Hao; Jiang, Bing

    2014-05-01

    A data set of phytoplankton community and environmental parameters in a hydrological integrity period, i.e. a poor water term, a medium term and a rich water term of North Temperate Zone climate, was analyzed in order to describe seasonal variation of phytoplankton community and its relationship with environmental variables in the Zhalong Wetland of China. The algal population of the Zhalong Wetland was not abundant, with a mean density of 5.08 × 10(7) cell/L (ranged from 4.54 × 10(7) cell/L in a poor term to 5.56 × 10(7) cell/L a medium term). However, its diversity was essentially limited to Cryptophyta, Bacillariophyta, Chlorophyta, Euglenophyta being the group with highest densities. There were considerable seasonal variations in phytoplankton composition. In general, the dominance of Bacillariophyceae was found in a medium term, which was higher than the other period (p NO2-N), suspend solid, nitrate (NO3-N), silicon dioxide (SiO2) and all the 10 physical-chemical parameters had a higher marginal effect and λA in the series of constrained CCAs though they were not significant.

  14. Diet of tadpoles of Physalaemus biligonigerus (Leiuperidae from agricultural ponds in the central region of Argentina

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    Clarisa de Lourdes Bionda

    2013-12-01

    Full Text Available The intensification of agriculture has led an important loss of natural habitats, with significant consequences for biodiversity. In this sense, the studies on anuran amphibian tadpoles inhabiting these environments are relevant, because the larval stage is a phase of population regulation. The aim of this study was to analyze the diet in Physalaemus biligonigerus tadpoles, an anuran species widely distributed in South America and that inhabit agroecosystems. Three sites were sampled; two agroecosystems with different alteration degrees (AG1 and AG2 and an uncultured (SM third place. The captured tadpoles were anesthetized, fixed and preserved in formaldehyde (10%. Subsequently, the complete intestine was removed and analyzed for food items under a binocular microscope. The diet in P. biligonigerus tadpoles has a dominance of algae Bacillariophyceae, mainly in agroecosystems, due to the presence of the genera Navicula, Nitzschia and Gomphonema. There was a considerable abundance of the Gomphonema genus in the AG2 site. In addition, in the AG1 site several non-diatom algae were particularly abundant in the diet, such as the genera Euglena, Oedogonium and Chaetophora. In the SM site, the non-diatom genus Oscillatoria was well represented in the diet. Tadpoles inhabiting the site with abundant crop and livestock (AG1 ingested a significantly smaller amount of food. The presence of certain algae associated with eutrophic environments could indicate some pollution in agroecosystems (AG1 and AG2. Larval diet is suggested as a potential bioindicator of environmental health for these areas.

  15. Feed of Siamese fighting fish, Betta splendens, (Regan, 1910 in open pond: live and formulated diets

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    L. H. Sipaúba-Tavares

    Full Text Available Abstract The growth rate and percent survival of Betta splendens when submitted to formulated diet and live food treatments are evaluated. The three different diets were used and designated as: formulated diet (basal diet; live food diet (plankton and mixed diet (formulated diet with plankton. The live food diet contained plankton belonging to an open pond. High mortality was reported with live food (plankton treatment whereas higher percent survival occurred with formulated diet. Highest specific growth rate, weight gain and final weight were reported in the mixed diet treatment and were significantly different (p<0.01 from those in formulated diet and live food treatments. The gut contents of B. splendens in mixed diet and live food treatments comprised, Rotifera and Bacillariophyceae species in high percentages or rather, over 78% of total organisms. Lecane sp. was the most ingested zooplankton species by B. splendens in both treatments (mixed diet and live food, with the phytoplankton species Asterionella sp. and Melosira sp. respectively in mixed diet and in live food, respectively. Results indicated that the formulated diet influenced the water parameters dissolved oxygen, total suspended solids, total dissolved solids and pH. The live food in the open pond was not enough to improve the growth rate and percent survival of B. splendens. The growth performance of B. splendens; had the best results with mixed diet which was capable of maintaining species’s survival (82% and development in artificial conditions, benefiting the culture management of ornamental fish.

  16. Kelimpahan dan Keanekaragaman Plankton di Perairan Selat Bali (Plankton Abundance and Diversity in the Bali Strait

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    Ruly Isfatul Khasanah

    2013-12-01

    Full Text Available Fitoplankton mempunyai peran sangat penting dalam suatu perairan, selain berada pada dasar rantai makanan sedangkan zooplankton merupakan herbivor pemangsanya. Penelitian mengenai kelimpahan dan keanekaragaman plankton di perairan Selat Bali dilakukan pada musim peralihan II (Nopember 2012 dan musim barat (Pebruari 2013. Penelitian bertujuan untuk mengamati perbedaan kelimpahan dan keanekaragaman plankton pada dua musim angin muson. Sampel air diambil dengan menggunakan water sampler sedangkan sampel plankton diambil secara horisontal dan vertikal  pada kedalaman 1 m dan 20 m dengan jaring plankton Kitahara bermata jaring 20 µm. Hasil pengukuran nutrien pada musim peralihan II memiliki kadar fosfat, nitrat, bahan organik, silikat dan klorofil-a lebih tinggi dibandingkan pada musim barat. Informasi tersebut memperkuat indikasi adanya perpindahan massa air dari lapisan yang lebih dalam ke lapisan yang lebih dangkal. Nutrien fosfat dan nitrat diperlukan untuk mempertahankan fungsi membran sel dan silikia dibutuhkan untuk pembentukan dinding sel terutama pada diatom. Hasil penelitian juga menunjukkan bahwa kelas diatom (Bacillariophyceae mencapai 95,9 % dari total jenis dan kelimpahan fitoplankton seluruh stasiun penelitian, sisanya berasal dari genus Dinophyceae. Kelimpahan fitoplankton tertinggi terjadi pada musim peralihan II dengan Rhizosolenia stolterfothii sebesar 51.405 sel.L-1 (80,1%, sedangkan pada musim barat copepoda ditemukan melimpah sebesar 8.178 ind.L-1 (88,3 %. Hasil ini mengindikasikan bahwa dengan kelimpahan plankton yang ditemukan perairan Selat Bali dinilai cukup potensial untuk mendukung kehidupan biota laut pelagis. Kata kunci: plankton, selat Bali, rhizosolenia stolterfothii, muson   Abstract Phytoplankton has important role as primary producer in the sea and act as base of food chain while zooplankton act as herbivore prey on them. Research on abundance and diversity of plankton at Bali Strait was performed during

  17. Perifiton en el mesohábitat de corredera de un arroyo serrano: dinámica estacional en relación a variables físico-químicas Periphyton in a run mesohabitat of a mountain stream: seasonal dynamics related to physicochemical parameters

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    M. Andrea Amaidén

    2011-12-01

    Full Text Available Se analizó la composición y la distribución de algas perifíticas en un mesohábitat de corredera del arroyo Achiras, al suroeste de Río Cuarto, Córdoba, estacionalmente durante el período 2005-2006. Se seleccionaron tres sitios de muestreo en el gradiente longitudinal de una zona serrana y pedemontana, donde se realizará la construcción de una presa. Esta investigación aporta los primeros resultados sobre la comunidad algal perifítica y sienta las bases para una profundización futura. Se determinaron 267 taxones, la clase Bacillariophyceae aportó 174, Chlorophyceae 78 y Cyanophyceae 15. La máxima similitud entre las muestras fue de 100 %, correspondiendo a los sitios 1 y 2 durante la primavera. La mayor abundancia promedio fue de 320.486 org.cm-2 para el sitio 3 durante el verano. La clasificación de las muestras separó dos grupos principales y conformó subgrupos. El CCA efectuado a muestras y especies mostró una separación del sitio 3, ubicado en el pedemonte, con mayor porcentaje de sedimento de menor tamaño y una menor velocidad de corriente respecto a los otros. Los sitios 1 y 2 se caracterizaron, en general, por un gradiente de pH. Todos los grupos formados por la clasificación estuvieron integrados, en su mayoría, por organismos del orden Biraphidales.Composition and distribution of periphytic algae in a run mesohabitat of the stream Achiras, southwest of Rio Cuarto, Cordoba, were analyzed seasonally during 2005-2006. Three sites were selected for sampling in the longitudinal gradient of a mountainous and piedmont area, where the construction of a dam is considered. This research provides the first results on the algal periphytic community and lays the groundwork for a deepening future. A total of 267 taxa were identified, the class Bacillariophyceae contributed with 174 taxa, Chlorophyceae with 78 and Cyanophyceae with 15. The maximum similarity between samples was 100%, corresponding to sites 1 and 2 during the

  18. Effects of nutrients enrichment on algal communities: an experimental in mesocosms approach Efeitos do enriquecimento de nutrientes em comunidades de algas: uma abordagem experimental em mesocosmos

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    Sirlene Aparecida Felisberto

    2011-06-01

    Full Text Available AIM: The effect of different concentrations of nutrients on algal communities living at the bottom of mesocosms was examined; METHODS: The experiment was carried out in the tributary of Rosana reservoir (Corvo river from November 22nd to December 16th of 2003. Mesocosms were set up in triplicate, with four treatments: nitrogen (N; phosphorus (P; nitrogen plus phosphorus (NP; plus a control treatment (C, consisting in addition of water from the reservoir; RESULTS: Results of the Principal Components Analysis applied on the abiotic variables have shown that two axes explained 93.6% of the total variability (69.6 and 23.9%, respectively. It was possible to identify a group of P (positive and N (negative treatments of axis 1. The addition of nutrients in the experiment resulted in changes in algal composition. Mean values of density ranged from 8.383 to 34.510 ind.mL-1. Higher densities occurred in the phosphorus and nitrogen plus phosphorus treatments. The most representative classes were Zygnemaphyceae, Chlorophyceae, Bacillariophyceae and Cyanobacteria, both in density and species richness; CONCLUSIONS: Phosphorus seems to be beneficial to green algae in general, since a marked increase in Zygnemaphyceae and Chlorophyceae was found in the treatments containing phosphorus and nitrogen plus phosphorus. In the nitrogen treatment, however, green algae decreased dramatically, while Cyanobacteria remained constant, indicating their capacity to live in changed environments and confirms the limiting role played by phosphorus on the algal groups.OBJETIVO: Este trabalho teve como objetivo avaliar a resposta das comunidades algais presente no sedimento de mesocosmos em diferentes concentrações de nutrientes; MÉTODOS: O experimento foi realizado no afluente do reservatório de Rosana (rio do Corvo no período de 22 de novembro a 16 de dezembro de 2003. Os mesocosmos foram preparados em triplicatas e em quatro tratamentos: (N com adição de nitrog

  19. Estudio Ficológico de lagos urbanos artificiales del sur de la provincia de Córdoba Phycological study of artificial urban reservoirs of the South of the province of Córdoba

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    Martín David Novoa

    2006-12-01

    Full Text Available El presente trabajo fue realizado en dos lagos urbanos artificiales de Río Cuarto (Córdoba: Parque Sarmiento y Villa Dalcar, durante el año 2003. El objetivo fue: conocer y comparar la composición algal, su relación con parámetros ambientales y registros bacteriológicos en ambos lagos. Se determinaron 275 taxa: 178 Bacillariophyceae , 60 Chlorophyceae , 21 Cyanophyceae , 13 Euglenophyceae , 2 Dinophyceae y 1 Chrysophyceae . Las especies y/o variedades fueron registradas por primera vez para el área de estudio, 53 son nuevas citas para la provincia de Córdoba y 8 para la Argentina. El lago con mayor número de especies propias fue el Villa Dalcar. El Parque Sarmiento en otoño, registró un gran número de clorofíceas propias de este lago. Se evidenciaron dos floraciones en el lago Villa Dalcar: estival de Aphanizomenon flos-aquae y primaveral de Peridinium pusillum . El índice de Jaccard evidenció la mayor similitud entre los sitios Este y Centro en otoño, para el lago Parque Sarmiento y Salida y Malón, en verano, para el lago Villa Dalcar. Según el Índice de Sorensen-Dice aplicado a ambos lagos y estaciones del año, la máxima similitud fue entre los sitios Salida del Villa Dalcar y Este del Parque Sarmiento, en invierno. En primavera y verano se registró un número elevado de bacterias coliformes en el sitio Puente Oeste del lago Parque Sarmiento , y en el sitio el Malón del lago Villa Dalcar, en verano.The present work was carried out in two urban lakes in Río Cuarto (Córdoba, Argentina: Parque Sarmiento and Villa Dalcar, during the year 2003. The objective was to know and to compare the algal composition and its relation with environmental parameters and bacteriological registries in both lakes. 275 taxa were determined: 178 Bacillariophyceae , 60 Chlorophyceae , 21 Cyanophyceae , 13 Euglenophyceae , 2 Dinophyceae and 1 Chrysophyceae. The species and/or varieties are registred for the irst time in the study area, 53 are

  20. Fatty acids composition of 10 microalgal species

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    Thidarat Noiraksar

    2005-11-01

    Full Text Available Fatty acids composition of 10 species of microalgae was determined at the exponential phase and the stationary phase. The microalgae consist of two species of diatoms, Bacillariophyceae, (Nitzschia cf. ovalis, Thalassiosira sp. five species of green microalgae, Prasinophyceae (Tetraselmis sp. and Chlorophyceae, (Dictyosphaerium pulchellum, Stichococcus sp., Chlorella sp., Scenedesmus falcatus and three species of blue green microalgae, Cyanophyceae (Anacystis sp., Synechococcus sp., Synechocystis sp..Medium for culture diatoms and green microalgae was F/2, and BG-11 media was used for Cyanophyceae. The microalgae were cultured beneath light intensity 143 μEm-2s-1, light: dark illustration 12:12 hrs., temperature 28ºC, and salinities 8-30 psu. The microalgae were harvested for analyzing fatty acid by centrivugal machine at 3500 rpm. for 5 min. at temperature 20ºC and stored at -80ºC prior to analysis.Fatty acids composition of microalgae differed from species to species. The majority fatty acids composition of diatoms at the exponential phase and the stationary phase were C16:1n-7 (17.12-31.47% and 28.22-42.02%, C16:0 (13.25-19.61% and 18.83-20.67%, C20:5 n-3 (16.65-26.67% and 11.32-23.68% respectively. The principle fatty acids composition of green microalgae, Prasinophyceae, Tetraselmis sp. were C18:3n-3 (16.17-16.67%, C16:0 (15.33-17.45%, C18:1n-9 (12.25-15.43%, C18:2n-6 (9.66-19.97%. The fatty acids composition of green microalgae, Chlorophyceae, were C18:3 n-3 (20.02-26.49% and 15.35- 30.63%, C16:0 (5.76-17.61% and 11.41-20.03%, C18:2n-6 (4.67-17.54% and 7.48-20.61% respectively. The major amounts of fatty acids content of blue green microalgae were C16:1n-7 (9.28-34.91% and 34.48- 35.04%, C14:0 (13.34-25.96% and 26.69-28.24%, C16:0 (5.89-29.15% and 5.70-16.81% except for Anacystis sp.which had a high amount of C18:3 n-3 (23.18-27.98% but low amount of C14:0 (3.66-4.98%.Bacillariophyceae contained the highest amount of highly unsaturated

  1. Resposta das algas perifíticas às alterações de temperatura e ao enriquecimento artificial de nutrientes em curto período de tempo - DOI: 10.4025/actascibiolsci.v31i3.1627 Periphytic algae response to temperature changes and artificial nutrient enrichment - DOI: 10.4025/actascibiolsci.v31i3.1627

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    Liliana Rodrigues

    2009-07-01

    Full Text Available O estudo visou avaliar, em um experimento de mesocosmos, a influência da temperatura e de concentrações de nutrientes na abundância das algas perifíticas (exceto Bacillariophyceae na planície de inundação do alto rio Paraná. O delineamento experimental constituiu-se de cinco tratamentos: controle (C e adição de nutrientes (P+, N+ e NP+ a 25°C, e frio (F com diminuição da temperatura a 15°C e sem adição de nutrientes. Lâminas de vidro foram utilizadas para colonização das algas perifíticas, e as amostragens foram feitas entre o 15° e o 31° dia de sucessão. Pela Análise de Correspondência Canônica, pode-se observar uma clara separação entre os tratamentos devido à temperatura e adição de nutrientes. A diminuição de temperatura afetou a abundância das classes de algas perifíticas, principalmente pela redução da densidade relativa de Cyanophyceae e aumento de Zygnemaphyceae. O enriquecimento artificial de nutrientes, principalmente P, alterou a estrutura da comunidade de algas perifíticas, em termos de densidade das classes algais. As densidades relativas das classes, em geral, aumentaram com a adição de nutrientes. O fósforo pode ser considerado direcionador na densidade das algas perifíticas, como pode ser observado pela rápida resposta após os enriquecimentos artificiais.This study set out to evaluate, via a mesocosm experiment, the influence of the temperature and concentration of nutrients (N and P in the abundance of periphytic algae (except Bacillariophyceae of the upper Paraná river floodplain. The experiment was designed using 5 treatments: a control (C, added nutrients (P+, N+, NP+ at 25°C, and without added nutrients at 15°C. Glass slides were used for periphytic algae colonization, and the samples were taken on the 15th and 31st days following colonization. Canonical Correspondence Analysis revealed a clear separation among treatment groups due to temperature and added nutrients. A decrease

  2. The effect of the land use on phytoplankton assemblages of a Cerrado stream (Brazil Os efeitos do uso do solo sobre as assembleias fitoplanctônicas de um riacho de Cerrado (Brasil

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    Mateus Ferrareze

    2012-03-01

    Full Text Available AIM: Our aim was to investigate whether land use from the adjacent terrestrial environment influences phytoplankton assemblage structure (composition, richness, diversity, and abundance and biomass (chlorophyll-a in a Cerrado stream during different periods of the year. METHOD: The fieldwork was carried out at each 3 months during two years. RESULTS: The physical and chemical variables that better indicated differences in water condition were conductivity, dissolved oxygen, and transparency. There was also a noticeable increase in the concentration of nitrogen, phosphorus, and suspended matter in the water during summer due to the direct effects of rainfall. The phytoplankton assemblages were composed by 64 species. Cryptophyceae was the most abundant group, followed by Bacillariophyceae. For both years, richness and diversity were higher during spring and autumn, while phytoplankton abundance and chlorophyll-a concentration were greater during autumn and summer. The cluster and the canonic correspondence analyses evidenced that seasonality and land use are important factors in structuring phytoplankton communities along the year. Alterations in phytoplankton assemblages registered herein were probably a consequence of variations on intensity and frequency of water mixing, along with the input of nutrients from the adjacent terrestrial system. CONCLUSION: Overall phytoplankton assemblage structure showed to be highly influenced by land use, corroborating our initial hypothesis.OBJETIVO: Nosso objetivo foi investigar se o uso do solo do ambiente terrestre adjacente influencia a estrutura das assembleias fitoplanctônicas (composição, riqueza, diversidade e abundância e biomassa (clorofila-a em um riacho de Cerrado durante diferentes períodos do ano. MÉTODOS: Os trabalhos de campo foram realizados trimestralmente durante dois anos. RESULTADOS: As variáveis físico-químicas que melhor indicaram as diferenças nas condições da água foram

  3. Diet seasonality and food overlap in fishes of the upper Orituco stream, northern Venezuela

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    Mario Ortaz

    2001-03-01

    Full Text Available The diets of four diurnal fish species (Creagrutus bolivari, Knodus deuterodonoides, Knodus sp. and Poecilia reticulata were examined during a year in the Orituco stream at northern Venezuela. The fishes were sampled monthly from February 1991 to March 1992 (except October 1991 and February 1992 in the stream main channel with a beach seine and a cast net. Diet is reported as frequency of ocurrence and numeric proportion because variation in prey sizes was small. Non-parametric statistical tests were applied. A total of 18 distinct prey items were found in stomachs. The diet of these fishes consisted of aquatic insects (Coleoptera, Diptera, Hemiptera, Odonata, Plecoptera and Trichoptera, allochthonous plant matter (fragments of leaves and seeds, microalgae (Chlorophyta and Bacillariophyceae and terrestrial arthropods (Coleoptera, Diptera, Hymenoptera and Arachnida. The low percentage of empty guts and the high fullness percentage of guts suggest that food was always abundant. Aquatic insects were more important in the dry season (November - April while plant matter and terrestrial arthropods increased in the wet season (May - October. The Proportional Similarity Measure (PS was high between characid species and low between characids and P. reticulata in the dry season. PS decreased during the wet season because of a reduction in aquatic insect consumption. The seasonal diet shift indicated the greater importance of allochthonous food only in the wet season.Se analizó la dieta de cuatro especies de peces (Creagrutus bolivari, Knodus deuterodonoides, Knodus sp. y Poecilia reticulata que habitan el río Orituco al norte de Venezuela. Los muestreos se realizaron mensualmente entre febrero de 1991 y marzo de 1992 (excepto octubre/91 y febrero/92. Los peces se recolectaron con chinchorro y atarraya en el canal principal del río. La dieta se expresó como frecuencia numérica y de ocurrencia y se analizó con pruebas estadísticas no param

  4. Ecología trófica en larvas de Rhinella arenarum (Anura: Bufonidae en agroecosistemas y sus posibles implicaciones para la conservación Trophic ecology in tadpoles of Rhinella arenarum (Anura: Bufonidae in agroecosystems and their possible implications for conservation

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    Clarisa Bionda

    2012-06-01

    , tadpoles, an anuran species widely distributed in South America and that inhabit agroecosystems. Three sites were sampled, two agroecosystems with different alteration degrees (C1 and C2 and an uncultured (SM third place. The captured tadpoles were anesthetized, fixed and preserved in formaldehyde (10%. Subsequently, body measurements were made and the complete intestine was removed and analyzed for food items under a binocular microscope. The diet in R. arenarum tadpoles has a dominance of algae Bacillariophyceae, followed by Cyanophyceae. In particular, the class Bacillariophyceae, due to the presence of the genus Navicula, Nitzschia, Gomphonema and Hantzschia, was important in the diet of the anurans in those agroecosystems. Class Cyanophyceae, mainly represented by genus Oscillatoria and Euglenophyceae represented by Euglena and Strombomonas, were predominant in the diet of the anurans in SM. Some differences in the total items consumed by tadpole were observed between the studied sites. Tadpoles that inhabit the modified sites (C1 and C2 recorded a significantly smaller amount of food. Moreover, the tadpoles that inhabit these sites showed a lower body condition. The presence of certain algae associated with eutrophic environments, could indicate some pollution in agroecosystems (C1 and C2. Food resources would be lesser in places with strong agricultural activity, possibly with a greater degree of eutrophication. A smaller food amount could have consequences at population level for the short and long time terms, because of its impact on individual growth. Larval diet is suggested as a potential bioindicator of environmental health for these areas. Rev. Biol. Trop. 60 (2: 771-779. Epub 2012 June 01.

  5. Please mind the gap – Visual census and cryptic biodiversity assessment at central Red Sea coral reefs

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    Pearman, John K.

    2016-04-26

    Coral reefs harbor the most diverse assemblages in the ocean, however, a large proportion of the diversity is cryptic and, therefore, undetected by standard visual census techniques. Cryptic and exposed communities differ considerably in species composition and ecological function. This study compares three different coral reef assessment protocols: i) visual benthic reef surveys: ii) visual census of Autonomous Reef Monitoring Structures (ARMS) plates; and iii) metabarcoding techniques of the ARMS (including sessile, 106–500 μm and 500–2000 μm size fractions), that target the cryptic and exposed communities of three reefs in the central Red Sea. Visual census showed a dominance of Cnidaria (Anthozoa) and Rhodophyta on the reef substrate, while Porifera, Bryozoa and Rhodophyta were the most abundant groups on the ARMS plates. Metabarcoding, targeting the 18S rRNA gene, significantly increased estimates of the species diversity (p < 0.001); revealing that Annelida were generally the dominant phyla (in terms of reads) of all fractions and reefs. Furthermore, metabarcoding detected microbial eukaryotic groups such as Syndiniophyceae, Mamiellophyceae and Bacillariophyceae as relevant components of the sessile fraction. ANOSIM analysis showed that the three reef sites showed no differences based on the visual census data. Metabarcoding showed a higher sensitivity for identifying differences between reef communities at smaller geographic scales than standard visual census techniques as significant differences in the assemblages were observed amongst the reefs. Comparison of the techniques showed no similar patterns for the visual techniques while the metabarcoding of the ARMS showed similar patterns amongst fractions. Establishing ARMS as a standard tool in reef monitoring will not only advance our understanding of local processes and ecological community response to environmental changes, as different faunal components will provide complementary information but

  6. HUBUNGAN ANTARA KANDUNGAN SILIKA DENGAN KELIMPAHAN DIATOM BENTHIK DI SEPANJANG SUNGAI PELUS KABUPATEN BANYUMAS

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    Siti Umiatun

    2017-03-01

    Full Text Available Silica is an element that is useful to the organism especially Diatoms (Chrysophyta: Bacillariophyceae. The sources of Silica in waters derive from weathering rock-containing silica. Diatoms are a phytoplankton that able to live as a phytobenthos distributed globally in all types of waters. The purpose of this study was to determine; the silica content, the abundance of diatoms, and the relationship between the content of silica and the abundance of diatoms in the Pelus River Banyumas. This research was conducted as a survey and samples were collected using composite sampling technique at 5 stations. Samples were collected three times with 2 weeks intervals. Two main parameters (diatoms abundance and silica content and ten supporting parameters (temperature, current velocity, pH, DO, BOD, COD, TSS, TDS, nitrate, and ortofosfat of waters were measured. Data of analysis calculated in this study including regression correlation analysis to determine the relationship of the silica content and the abundance of diatoms. The silica concentration in the Pelus River waters varies between 112.48-175.00 mg.l-1 with an average of 146 mg.l-1. The total abundance of benthic diatoms was 44,442 ind.cm-2. The highest diatoms abundance was at station II (11,128 ind.cm-2, the lowest was at Station IV (6,828 ind.cm-2. The relationship between silica contained in the waters and abundance of diatoms indicated by the value of R2 (coefficient of determination by 0.38 or 38%. The abundance of Diatoms are affected 62% by the available silica in the environment, and the rest 38% e rest are determined by other factors.

  7. Production of silver nanoparticles by the diatom Phaeodactylum tricornutum

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    Wishkerman, Asher; Arad (Malis), Shoshana

    2017-05-01

    Diatoms (Bacillariophyceae) are the most species-rich group of algae, they are single-celled characterized by a silicified cell wall called a frustule. Diatoms are diverse in shape with many distinct features like raphe and fultoportulae. The diatom cell wall morphology and its hierarchy structure make it a unique unicellular organism for nanotechnology research and applications. Diatom cells are a promising system for green synthesis of nanomaterials like metallic nanoparticles (NPs), nanostructured polymers and other nanomaterials. The production of NPs is achieved today by using methods like attrition or pyrolysis. The cost and the toxic substances often used in these common methods of NPs synthesis limit their applications. Therefore, NPs biosynthesis by diatom cultures, which can be done at ambient CO2 concentrations, temperature and pressure, offers a sustainable alternative solution. In this work, we examined the formation of silver NPs (AgNPs) by the diatom Phaeodactylum tricornutum cultivated at 25°C for a period of 8 days. Using this approach, diatom cultures were either grown throughout the duration of the experiment in an artificial seawater (ASW)-f/2 medium enriched with 1 ppm Ag+ or grown in an ASW-f/2 medium where similar silver ion concentrations were added on experimental day 4. We found that 1 ppm Ag+ reduces the P. tricornutum growth by up to 50% as compared with the control. Moreover, scanning electron microscopy (SEM) in combination with Energy-Dispersive X-ray (EDX) showed the presence of AgNPs nanoparticles with different sizes and chemical composition associated with the diatom frustules and extracellular polymeric substances.

  8. Phytoplankton assemblages in a reservoir cascade of a large tropical - subtropical river (SE, Brazil

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    MG Nogueira

    Full Text Available The phytoplankton assemblages from eight reservoirs of the Paranapanema River were studied during two consecutive years. Chlorophyceae and Bacillaryophyceae dominated in richness. The observed high number of taxa, 234, reflects the extensive sampling programme and evidences the necessity of considering the whole hydrograph basin to assess the biodiversity status of inland water ecosystems. The dams had a negative effect on phytoplankton richness, with higher number of taxa associate to riverine (non-regulated stretches. The tributary rivers also exhibited high species richness, showing the importance of considering the lateral dimension, in addition to the longitudinal one, for aquatic biota inventories in large river basins/reservoirs. Richness and diversity were also positively influenced by the connectivity with lateral wetlands (macrophyte-dominated lakes due to the periphyton influence. The phytoplankton abundance/biomass was not influenced by higher water retention time. Higher values occurred in the middle basin stretches (river-passage reservoirs due to the increase in the trophic conditions. There was a positive correlation with phosphorus. Poorer light conditions in the cascade do not limit the phytoplankton biomass, with assemblages dominated by species tolerant to turbulent conditions and high mineral turbidity. Bacillariophyceae and Cryptophyceae dominated numerically. The first group (unicellular forms was prominent in the large and oligotrophic upstream reservoirs. The second was highly abundant in the river-passage (low retention time, and more eutrophic, reservoirs. Cyanophyceae growth is probably controlled by advection processes (wash-out effect. The zooplankton does not control the phytoplankton biomass and the diversity of both groups is positively associated in the cascade. The structure of the phytoplankton assemblages showed to be a good indicator of the operationally distinct reservoirs of the Paranapanema cascade and

  9. Nutrient ratios and the complex structure of phytoplankton communities in a highly turbid estuary of Southeast Asia.

    Science.gov (United States)

    Chu, Thuoc Van; Torréton, Jean-Pascal; Mari, Xavier; Nguyen, Huyen Minh Thi; Pham, Kha Thi; Pham, Thu The; Bouvier, Thierry; Bettarel, Yvan; Pringault, Olivier; Bouvier, Corinne; Rochelle-Newall, Emma

    2014-12-01

    Phytoplankton diversity and abundance in estuarine systems are controlled by many factors. Salinity, turbidity, and inorganic nutrient concentrations and their respective ratios have all been proposed as principal factors that structure phytoplankton diversity and influence the emergence of potentially toxic species. Although much work has been conducted on temperate estuaries, less is known about how phytoplankton diversity is controlled in tropical, monsoonal systems that are subject to large, seasonal shifts in hydrology and to rapidly changing land use. Here, we present the results of an investigation into the factors controlling phytoplankton species composition and distribution in a tropical, monsoonal estuary (Bach Dang estuary, North Vietnam). A total of 245 taxa, 89 genera from six algal divisions were observed. Bacillariophyceae were the most diverse group contributing to 51.4 % of the microalgal assemblage, followed by Dinophyceae (29.8 %), Chlorophyceae (10.2 %), Cyanophyceae (3.7 %), Euglenophyceae (3.7 %) and Dictyochophyceae (1.2 %). The phytoplankton community was structured by inorganic nutrient ratios (DSi:DIP and DIN:DIP) as well as by salinity and turbidity. Evidence of a decrease in phytoplankton diversity concomitant with an increase in abundance and dominance of certain species (e.g., Skeletonema costatum) and the appearance of some potentially toxic species over the last two decades was also found. These changes in phytoplankton diversity are probably due to a combination of land use change resulting in changes in nutrient ratios and concentrations and global change as both rainfall and temperature have increased over the last two decades. It is therefore probable in the future that phytoplankton diversity will continue to change, potentially favoring the emergence of toxic species in this system.

  10. Ecological assessment of the macrophytes and phytoplankton in El-Rayah Al-Behery, River Nile, Egypt

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    Amany M. Haroon

    2017-09-01

    Full Text Available The present study aimed to assess the effect of ecological factors on distribution and species composition of macrophytes and phytoplankton communities at El-Rayah Al-Behery. Changes in the quantitative and qualitative composition of the macrophytes and phytoplankton communities were detected in relation to season and sampling site. A total of eleven macrophytes and 100 phytoplankton species were identified. Among the macrophytes, the emergent species Echinochloa stagnina was the most dominant and widely distributed. Phytoplankton community is fairly diverse, related to 7 classes, which contains 3 main classes: Bacillariophyceae (28 taxa, Chlorophyceae (33 taxa and Cyanophyceae (23 taxa. According to statistical analysis, occurrence of most macrophytes species were reversely affected by DO, COD, BOD and PO4; and closely correlated with NO2, NO3, Temp. and pH values. However, nitrogen and phosphorus are considered as limiting factors for bacillariohyceae growth (r = 0.7. Both temperature and pH have a positive effect on the growth of chlorophyceae (r = 0.9 and 0.8, respectively; while dissolved oxygen is an important parameter that affects on the growth of cyanphyceae (r = 0.8. In addition, existence of Myriophyllium spicatum was associated with increasing of bacillariohyceae and total phytoplankton density (r = 0.7. However, the presence of Polygonum tomentosum was intensely related with chlorophyceae (r = 0.9 and Potamogeton nodosus and Polygonum tomentosum were positively correlated with cyanphyceae. In conclusion, the investigated area was characterized by different taxonomic composition of macrophytes and phytoplankton communities, which varied as a result of changing in water physiochemical characteristics as well as the interaction between different species. Keywords: Ecological assessment, Phytoplankton, Macrophytes

  11. Chironomidae feeding habits in different habitats from a Neotropical floodplain: exploring patterns in aquatic food webs.

    Science.gov (United States)

    Butakka, C M M; Ragonha, F H; Train, S; Pinha, G D; Takeda, A M

    2016-02-01

    Ecological studies on food webs have considerably increased in recent decades, especially in aquatic communities. Because Chironomidae family are highly specious, occurring in almost all aquatic habitats is considered organisms-key to initiate studies on ecological relationships and trophic webs. We tested the hypothesis that the diversity of the morphospecies diet reflects differences on both the food items available among habitats and the preferences of larval feeding. We analyzed the gut content of the seven most abundant Chironomidae morphospecies of the different habitats from the Upper Paraná River. We categorized the food items found into algae, fungal spores, fragments of plants, algae and animal fragments and sponge spicules. We observed the algae predominance in the gut content of morphospecies from lakes. Considering the different regions from each lake, we registered the highest food abundance in the littoral regions in relation to the central regions. From the variety of feeding habits (number of item kinds), we classified Chironomus strenzkei, Tanytarsus sp.1, Procladius sp.1 as generalist morphospecies. We found a nested pattern between food items and Chironomidae morphospecies, where some items were common to all taxa (e.g., Bacillariophyceae algae, especially), while others were found in specific morphospecies (e.g., animals fragments found in Procladius sp.1). The algae represented the most percentage of gut contents of Chironomidae larvae. This was especially true for the individuals from littoral regions, which is probably due to the major densities of algae associated to macrophytes, which are abundant in these regions. Therefore, the feeding behavior of these morphospecies was generalist and not selective, depending only of the available resources.

  12. Seasonal dynamics of phytoplankton community in a tropical wetland.

    Science.gov (United States)

    Bhat, Najeeb Ahmad; Wanganeo, Ashwani; Raina, Rajni

    2015-01-01

    Phytoplankton species composition and seasonal changes were investigated in the Bhoj wetland Bhopal. Taxonomic composition, diversity, and abundance of phytoplankton were studied at nine stations from March 2008 to February 2010, in relation to various physico-chemical factors. Total phytoplankton species composition in the Bhoj wetland was represented by 360 species. Among phytoplankton, diversity belonged to seven groups. Chlorophyceae was the dominant group (48%) followed by Bacillariophyceae (26%), Cyanophyceae (15%), and Euglenophyceae (9%), while Pyrophyceae, Chrysophyceae, and Xanthophyceae contributed 2% of the population. Phytoplankton on the basis of seasonal studies recorded 1651 units l(-1) during summer season which was contributed mainly by Chlorophyceae (39.3%), with Spirogyra sp. (14.2%) and Closteriopsis sp. (9.1%) contributing maximum to the total group in the first year, while during the second year of summer period, a total of 2095 units l(-1) was recorded which was contributed mainly by group Pyrophyceae (51%) with the main dominant species represented by Ceratium hirundinella (98.46%). The highest Shannon-Wiener diversity index (H') value (4.27) was recorded. Simpson values are approaching 1, signifying that sites have high relative diversity due to its supporting surrounding components. The trend of variation in evenness values was more or less the same as Shannon diversity index. Thus, the highest diversity indices recoded at all the stations in the present study justify the diverse nature of species inhabiting the different ecological niches in the ecosystem. The very high phosphate and nitrate concentrations in the wetland are indicators of pollution which may be due to the discharge of agricultural and sewage wastes enriched with nutrients as well as the human activities there. Our recommendation is to avoid as far as possible the discharge of sewage and agriculture wastes into the Bhoj wetland. The effects of various physicochemical

  13. Tingkat Pencemaran Berdasarkan Saprobitas Plankton di Perairan Pelabuhan Benoa, Kota Denpasar, Provinsi Bali

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    Ni Putu Eva Damayanti

    2017-09-01

    Full Text Available Plankton is organism that susceptible to environmental changes that used as indicator of environmental pollution by saprobic index because plankton has important role in affecting the water primary productivity. The research about plankton saprobic in Benoa Harbour is never done before. The aim of this research is to explain the structure of community and the level of plankton saprobic at Benoa Harbour. This research using random sampling method for determine the station. The result explained that there was 17 species of plankton in the waters of Benoa Harbor from two classes such as Bacillariophyceae, Dinophyceae on phytoplankton and from five classes such as Magnoliopsida, Malacostraca, Maxillopoda, Globothalamea and Hexanauplia on zooplankton. The total abundance of plankton ranges from 1.117.172 Individual / Liter- 1.626.163 Individual / Liter. The zooplankton diversity index in the waters of Benoa Harbor ranges from 1.06 to 1.58 and phytoplankton ranges from 1.02 to 155. This indicates that the value of diversity in all observation stations is categorized into low biodiversity. Zooplankton evenness index value in the waters of Benoa Harbor ranged from 0.73-0.88 and phytoplankton ranged from 0.71-0.96. This indicates that the index of evenness is relatively high. The dominant value of zooplankton in the waters of Benoa Harbor ranges from 0.24-0.43 and phytoplankton ranged from 0.22-0.41. This indicates that the dominance is relatively low. Saprobik Index (SI value ranges from 1.0-1.6 and Tropic Saprobic Index (TSI ranges from 1.76-1.96. This indicates that the waters of Benoa Harbour is categorized mild contaminated conditions until not contaminated.

  14. Analysis of diversity of chromophytic phytoplankton in a mangrove ecosystem using rbcL gene sequencing.

    Science.gov (United States)

    Samanta, Brajogopal; Bhadury, Punyasloke

    2014-04-01

    Phytoplankton forms the basis of primary production in mangrove environments. The phylogeny and diversity based on the amplification and sequencing of rbcL, the large subunit encoding the key enzyme ribulose-1, 5-bisphosphate carboxylase/oxygenase was investigated for improved understanding of the community structure and temporal trends of chromophytic eukaryotic phytoplankton assemblages in Sundarbans, the world's largest continuous mangrove. Diatoms (Bacillariophyceae) were by far the most frequently detected group in clone libraries (485 out of 525 clones), consistent with their importance as a major bloom-forming group. Other major chromophytic algal groups including Cryptophyceae, Haptophyceae, Pelagophyceae, Eustigmatophyceae, and Raphidophyceae which are important component of the assemblages were detected for the first time from Sundarbans based on rbcL approach. Many of the sequences from Sundarbans rbcL clone libraries showed identity with key bloom forming diatom genera namely Thalassiosira, Skeletonema and Nitzschia. Similarly, several rbcL sequences which were diatom-like were also detected highlighting the need to explore diatom communities from the study area. Some of the rbcL sequences detected from Sundarbans were ubiquitous in distribution showing 100% identities with uncultured rbcL sequences targeted previously from the Gulf of Mexico and California upwelling system that are geographically separated from study area. Novel rbcL lineages were also detected highlighting the need to culture and sequence phytoplankton from the ecoregion. Principal component analysis revealed that nitrate is an important variable that is associated with observed variation in phytoplankton assemblages (operational taxonomic units). This study applied molecular tools to highlight the ecological significance of diatoms, in addition to other chromophytic algal groups in Sundarbans. © 2014 Phycological Society of America.

  15. Comparison of potential diatom 'barcode' genes (the 18S rRNA gene and ITS, COI, rbcL) and their effectiveness in discriminating and determining species taxonomy in the Bacillariophyta.

    Science.gov (United States)

    Guo, Liliang; Sui, Zhenghong; Zhang, Shu; Ren, Yuanyuan; Liu, Yuan

    2015-04-01

    Diatoms form an enormous group of photoautotrophic micro-eukaryotes and play a crucial role in marine ecology. In this study, we evaluated typical genes to determine whether they were effective at different levels of diatom clustering analysis to assess the potential of these regions for barcoding taxa. Our test genes included nuclear rRNA genes (the nuclear small-subunit rRNA gene and the 5.8S rRNA gene+ITS-2), a mitochondrial gene (cytochrome c-oxidase subunit 1, COI), a chloroplast gene [ribulose-1,5-biphosphate carboxylase/oxygenase large subunit (rbcL)] and the universal plastid amplicon (UPA). Calculated genetic divergence was highest for the internal transcribed spacer (ITS; 5.8S+ITS-2) (p-distance of 1.569, 85.84% parsimony-informative sites) and COI (6.084, 82.14%), followed by the 18S rRNA gene (0.139, 57.69%), rbcL (0.120, 42.01%) and UPA (0.050, 14.97%), which indicated that ITS and COI were highly divergent compared with the other tested genes, and that their nucleotide compositions were variable within the whole group of diatoms. Bayesian inference (BI) analysis showed that the phylogenetic trees generated from each gene clustered diatoms at different phylogenetic levels. The 18S rRNA gene was better than the other genes in clustering higher diatom taxa, and both the 18S rRNA gene and rbcL performed well in clustering some lower taxa. The COI region was able to barcode species of some genera within the Bacillariophyceae. ITS was a potential marker for DNA based-taxonomy and DNA barcoding of Thalassiosirales, while species of Cyclotella, Skeletonema and Stephanodiscus gathered in separate clades, and were paraphyletic with those of Thalassiosira. Finally, UPA was too conserved to serve as a diatom barcode. © 2015 IUMS.

  16. Aurelia aurita ephyrae reshape a coastal microbial community

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    Luca eZoccarato

    2016-05-01

    Full Text Available Over the last two decades, increasing attention has been paid to the impact of jellyfish blooms on marine communities. Aurelia aurita is one of the most studied of the Scyphozoans, and several studies have been carried out to describe its role as a top-down controller within the classical food web. However, little data are available to define the effects of these jellyfish on microbial communities. The aims of this study were to describe the predation impact of A. aurita ephyrae on a natural microplanktonic assemblage, and to determine any reshaping effects on the prokaryote community composition and functioning. Surface coastal water was used to set up a 24-h grazing experiment in microcosms. Samples were collected to determine the variations in prey biomass, heterotrophic carbon production, extracellular leucine aminopeptidase activity, and grazing pressure. A next-generation sequencing technique was used to investigate biodiversity shifts within the prokaryote and protist communities through the small subunit rRNA tag approach. This study shows that A. aurita ephyrae were responsible for large decreases in the abundances of the more motile microplankton groups, such as tintinnids, Dinophyceae, and aloricate ciliates. Bacillariophyceae and Mediophyceae showed smaller reductions. No evidence of selective predation emerged in the analysis of the community diversity down to the family level. The heterotrophic prokaryote biomass increased significantly (by up to 45%, in parallel with increases in heterotrophic carbon production and leucine aminopeptidase activity (40%. Significant modifications were detected in prokaryotic community composition. Some classes of Gammaproteobacteria and Flavobacteriia showed higher relative abundances when exposed to A. aurita ephyrae, while there was a net decrease for Alphaproteobacteria. Overall, this study provides new insight into the effects of A. aurita on microbial communities, underlining their selective

  17. Phytoplankton and bacterial community structures and their interaction during red-tide phenomena

    Science.gov (United States)

    Ismail, Mona Mohamed; Ibrahim, Hassan Abd Allah

    2017-09-01

    Phytoplankton and bacteria diversity were studied before, during and after red tide phenomena during spring season 2015 in the Eastern Harbour (E.H.) of Alexandria, Egypt. Fifty five species of phytoplankton were identified and represented different distinct classes "Bacillariophyceae; Dinophyceae, Chlorophyceae, Cyanophyceae and Eugelenophyceae". Also, Diatom formed the most dominant group. The average number of the phytoplankton density varied from 4.8 × 104 to 1.1 × 106 cell l-1 during the study period and Skeletonema costatum was the agent causing the red tide. The existence percentages of bacteria ranged from 2.6 to 17.9% on all media tested. The bacterial isolates on the nutrient agar medium represented the highest existence with a total percentage of 43.6%, followed by MSA medium (25.7%), while the lowest percentage was for the AA medium at 7.8%. However, twelve isolates were selected as representative for bacterial community during study interval. Based on the morphological, biochemical, physiological and enzymatic characteristics, the bacterial strains were described. Depending on the 16S rDNA gene sequence, three common antagonists were aligned as: Vibrio toranzoniae strain Vb 10.8, Ruegeria pelagia strain NBRC 102038 and Psychrobacter adeliensis strain DSM 15333. The interaction between these bacteria and S. costatum was studied. The growth of S. costatum was significantly lower whenever each bacterium was present as compared to axenic culture. More specifically, 30% (v/v) of the all tested bacteria showed the strongest algicidal activities, as all S. costatum cells were killed after two days. 10% of R. pelagia and P. adeliensis also showed significant algicidal activities within six days.

  18. Effects of copper on species composition of periphyton in a Sierra Nevada, California, stream

    Energy Technology Data Exchange (ETDEWEB)

    Leland, H.V.; Carter, J.L.

    1984-06-01

    Changes in species composition of the periphyton of an oliotrophic, Sierra Nevada stream continuously dosed for 1 year at three concentrations of copper (2.5, 5 and 10..mu..g 1/sup -1/ Cu/sub T/; approximately 12, 25 and 50 ng 1/sup -1/ Cu/sup 2 +/) were determined. The numerically most abundant taxa were Bacillariophyceae (Achnanthes minutissima, Cocconeis placentula, Cymbella microcephala, C. sinuata, Fragilaria construens, F. crotonensis, Navicula spp., Synedra acus and S. rumpens), and the Cyanophyta Lynbya spp., a co-dominant during spring and summer. Population densities of Lyngbya spp. were markedly reduced at all test concentrations of copper. Population densities of the principal Chlorophyta (Spirogyra spp. and Cladophora spp.) and the diatom Amphipleura pellucida were reduced at 5 ..mu..g 1/sup -1/ Cu/sub T/. Of the twenty-two most abundant taxa, sixteen were reduced in abundance by continuous exposure to 10 ..mu..g 1/sup -1/ Cu/sub T/. There was no commensurate reduction in standing crop (total number of individuals of all taxa). Achnanthes minutissima, a co-dominant in the control, was the primary replacement species. Other taxa that were more abundant at 5 ..mu..g 1/sup -1/ Cu/sub T/ than in the control were Ceratoneis arcus, Cocconeis placentula, Navicula spp. and Synedra rumpens. Only A. minutissima and Calothrix spp. were more abundant at l10 ..mu..g 1/sup -1/ than in the control. Three resemblance measures (Canberra metric, Bray-Curtis and Dice) and diversity (Brillouin's) were evaluated for detecting differences in species composition among experimental stream sections. The Canberra metric, an index sensitive to proportional rather than absolute differences, was the most informative of these indices.

  19. Phytoplankton relationship with bacterioplankton, dissolved carbohydrates and water characteristics in a subtropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    Pablo S. Guimarães

    2013-10-01

    Full Text Available Release of carbohydrates by phytoplankton enhances microbial diversity, promoting associations between algae and heterotrophic organisms. Thus, this work aimed to characterise the dissolved carbohydrates at a Brazilian subtropical coastal lagoon (Merin lagoon, in addition to determining their relationships with environmental parameters and phyto/bacterioplankton communities over one year. We analysed the relationships among physical, chemical and biological parameters by a principal component analysis (PCA after normalisation of data as z scores. Chlorophyceae showed the highest richness, although Bacillariophyceae and Cyanophyceae showed the highest densities. These classes are essentially represented by centric diatoms (Aulacoseira cf. muzzanensis and filamentous cyanobacteria (Planktolyngbya limnetica and Planktolyngbya cf. contorta. Merin lagoon showed a strong seasonal behaviour for most of parameters and phytoplanktonic density was mainly correlated with temperature, specific conductance, phosphate and total bright sunshine duration. Only combined dissolved carbohydrates (CDCHOs were found and their main components were glucose (31.6%, mannose/xylose (20.6%, ribose (13.9%, arabinose (8.9% and galacturonic acid (8.1%. The CDCHO amounts were higher in November, March-April and September and the December/January and July/August periods showed lower ones. Ribose was first detected only in the warm months and it gradually decreased with bacterial density. The carbohydrate concentration was coupled to phytoplanktonic density, except in December and January, when the bacterial density was increased. These results supported the significance of dissolved carbohydrates in associations with algae and bacteria in the freshwater planktonic environment. Our data reinforced the influence of phytoplankton community on the natural dissolved carbohydrate pool, besides the significance of such carbon source on the bacterial community dynamic.

  20. Environmental occurrence of the enterococcal surface protein (esp) gene is an unreliable indicator of human fecal contamination.

    Science.gov (United States)

    Byappanahalli, Muruleedhara N; Przybyla-Kelly, Katarzyna; Shively, Dawn A; Whitman, Richard L

    2008-11-01

    The enterococcal surface protein (esp) gene found in Enterococcus faecalis and E. faecium has recently been explored as a marker of sewage pollution in recreational waters but its occurrence and distribution in environmental enterococci has not been well-documented. If the esp gene is found in environmental samples, there are potential implications for microbial source tracking applications. In the current study, a total of 452 samples (lake water, 100; stream water, 129; nearshore sand, 96; and backshore sand, 71; Cladophora sp. (Chlorophyta), 41; and periphyton (mostly Bacillariophyceae), 15) collected from the coastal watersheds of southern Lake Michigan were selectively cultured for enterococci and then analyzed for the esp gene by PCR, targeting E. faecalis/ E. faecium (esp(fs/fm)) and E. faecium (esp(fm)). Overall relative frequencies for esp(fs/fm) and esp(fm) were 27.4 and 5.1%. Respective percent frequency for the esp(fs/fm) and esp(fm) was 36 and 14% in lake water, 38.8 and 2.3% in stream water, 24 and 6.3% in nearshore sand; 0% in backshore sand; 24.4 and 0% in Cladophora sp.; and 33.3 and 0% in periphyton. The overall occurrence of both esp(fs/fm) and esp(fm) was significantly related (chi2 = 49, P esp(fs/fm) increased in lake and stream water and nearshore sand. Further, E. coli and enterococci cell densities were significant predictors for esp(fs/fm) occurrence in post-rain lake water, but esp(fm) was not F+ coliphage densities were not significant predictors for esp(fm) or esp(fs/fm) gene incidence. In summary, the differential occurrence of the esp gene in the environment suggests that it is not limited to human fecal sources and thus may weaken its use as a reliable tool in discriminating contaminant sources (i.e., human vs. nonhuman).

  1. Future climate scenarios for a coastal productive planktonic food web resulting in microplankton phenology changes and decreased trophic transfer efficiency.

    Science.gov (United States)

    Calbet, Albert; Sazhin, Andrey F; Nejstgaard, Jens C; Berger, Stella A; Tait, Zachary S; Olmos, Lorena; Sousoni, Despoina; Isari, Stamatina; Martínez, Rodrigo A; Bouquet, Jean-Marie; Thompson, Eric M; Båmstedt, Ulf; Jakobsen, Hans H

    2014-01-01

    We studied the effects of future climate change scenarios on plankton communities of a Norwegian fjord using a mesocosm approach. After the spring bloom, natural plankton were enclosed and treated in duplicates with inorganic nutrients elevated to pre-bloom conditions (N, P, Si; eutrophication), lowering of 0.4 pH units (acidification), and rising 3°C temperature (warming). All nutrient-amended treatments resulted in phytoplankton blooms dominated by chain-forming diatoms, and reached 13-16 μg chlorophyll (chl) a l-1. In the control mesocosms, chl a remained below 1 μg l-1. Acidification and warming had contrasting effects on the phenology and bloom-dynamics of autotrophic and heterotrophic microplankton. Bacillariophyceae, prymnesiophyceae, cryptophyta, and Protoperidinium spp. peaked earlier at higher temperature and lower pH. Chlorophyta showed lower peak abundances with acidification, but higher peak abundances with increased temperature. The peak magnitude of autotrophic dinophyceae and ciliates was, on the other hand, lowered with combined warming and acidification. Over time, the plankton communities shifted from autotrophic phytoplankton blooms to a more heterotrophic system in all mesocosms, especially in the control unaltered mesocosms. The development of mass balance and proportion of heterotrophic/autotrophic biomass predict a shift towards a more autotrophic community and less-efficient food web transfer when temperature, nutrients and acidification are combined in a future climate-change scenario. We suggest that this result may be related to a lower food quality for microzooplankton under acidification and warming scenarios and to an increase of catabolic processes compared to anabolic ones at higher temperatures.

  2. PHYTOPLANKTON OF VRANSKO LAKE ON THE ISLAND CRES

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    Marija Tomec

    1996-06-01

    Full Text Available As a special nature phenomenon, Vransko Lake with its ackreage of 5.7 km2 and cubic capacity of 220 million m3 fresh-water of extraordinary quality has been unsufficiently biologically examined. Ichthyological, physical, chemical and bacteriological examination were conducted in 1989 (June, September and December and 1990 (April, Special attention was given to the examination of phytoplankton structure as an indicator of water quality. In addition to collecting phytoplankton specimen, the temperature and transparency of water were measured at 5 different places (Picture 1. The phytoplankton specimen Were taken at the depths of 0.5 m, 10 m, 20 m and 40 m. The results of medium values of measured water temperature and lake transparency are showed on the Picture 2. The water temperature s was mostly under the influence of surrounding air temperature. The thermic stratification in summer and the manifestation of isotherm in the colder period of year were observed. In the qualitative composition of phytoplankton there were stated sixty plankton algae which belonged to the following system groups: Cyanophyceae, Euglenophyceae, Dinophyceae, Chryslophyceae and Chlorophyceae (Table 1. While representatives of Bacillariophyceae outnumbered other groups, the species Cera- tium hirundinella which belongs to the Dinophyceae group and the indicator of olighosaprobnog degree dominated in all phytoplankton specimen of Vransko Lake. Besides that group, the significant role in the phytoplankton structure had the species Cyclotella comta, the indicator of olighosaprobnog degree and Dinobryon divergens, the indicator of bethamesosaprobnog degree. On the basis of qualitative analysis of phytoplankton, the representatives of olighosaprobnog degree dominated in Vransko Lake what implies good water quality and the quantitative analysis show the olighothrophic lake character. According to representation of particular phytoplankton species at the time of examination, the

  3. Phytoplankton community and limnochemistry of Piburger See (Tyrol, Austria 28 years after lake restoration

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    Hansjörg THIES

    2002-02-01

    Full Text Available Phytoplankton community and limnochemistry of Piburger See, a small soft-water, meromictic lake situated at 913 m a.s.l. in a crystalline area of the Central Eastern Alps of Tyrol (Austria, were investigated 28 years after the beginning of lake restoration. Although long-term data of the lake show a declining trend in total phosphorus concentrations and phytoplankton biovolume, the response of Piburger See to the restoration measures carried out in 1970 was delayed by about 20 years. At present the lake is approaching its former oligotrophic level. The most evident difference between the past and present phytoplankton species composition of Piburger See is the actual absence of the Cyanophycean Oscillatoria limosa C. A. Agardh, which markedly increased during the first two decades after the lake restoration (1970-1987. The phytoplankton biovolume recorded in 1998 was lower than in the 1970s and 1980s, while seasonal patterns were similar to those recorded before and later on in the lake restoration. The lowest annual phytoplankton biovolume in 1998 occurred in early winter, while the absolute maximum was observed in metalimnetic water layers in late spring. In 1998 the intra-annual patterns of phytoplankton biovolume and chlorophyll-a compare well. Phytoplankton succession started in early 1998 under ice with coccal green algae followed by flagellated Chrysophyceae during spring. The mid-summer phytoplankton community was dominated by centric Bacillariophyceae, which were later replaced by coccal Cyanophyceae. During autumn, Dinophyceae and Chrysophyceae prevailed. Epilimnetic dominance of centric diatoms during mid summer appears to be a new feature, which in 1998 was related to a strong depletion of dissolved silica and nitrate. Long-term water chemistry and phytoplankton data were checked against local weather data in order to explain the delay in the re-oligotrophication process of Piburger See. However, no clear relationship could be

  4. Environmental occurrence of the enterococcal surface protein (esp) gene is an unreliable indicator of human fecal contamination

    Science.gov (United States)

    Byappanahalli, M.N.; Przybyla-Kelly, K.; Shively, D.A.; Whitman, R.L.

    2008-01-01

    The enterococcal surface protein (esp) gene found in Enterococcus faecalis and E. faecium has recently been explored as a marker of sewage pollution in recreational waters but its occurrence and distribution in environmental enterococci has not been well-documented. If the esp gene is found in environmental samples, there are potential implications for microbial source tracking applications. In the current study, a total of 452 samples (lake water, 100; stream water, 129; nearshore sand, 96; and backshore sand, 71; Cladophora sp. (Chlorophyta), 41; and periphyton (mostly Bacillariophyceae), 15) collected from the coastal watersheds of southern Lake Michigan were selectively cultured for enterococci and then analyzed for the esp gene by PCR, targeting E. faecalis/ E. faecium (espfs/fm) and E. faecium (espfm). Overall relative frequencies for espfs/fm and espfm were 27.4 and 5.1%. Respective percent frequency for the espfs/fm and espfm was 36 and 14% in lake water; 38.8 and 2.3% in stream water; 24 and 6.3% in nearshore sand; 0% in backshore sand; 24.4 and 0% in Cladophora sp.; and 33.3 and 0% in periphyton. The overall occurrence of both espfs/fm and espfm was significantly related (χ2 = 49, P espfs/fm increased in lake and stream water and nearshore sand. Further, E. coli and enterococci cell densities were significant predictors for espfs/fm occurrence in post-rain lake water, but espfm was not. F+ coliphage densities were not significant predictors for espfm or espfs/fm gene incidence. In summary, the differential occurrence of the esp gene in the environment suggests that it is not limited to human fecal sources and thus may weaken its use as a reliable tool in discriminating contaminant sources (i.e., human vs nonhuman).

  5. Fitoperifiton composition and structure of the middle and lower basin of the river Cesar, Cesar Department-Colombia

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    Ana De la parra-Guerra

    2017-05-01

    Full Text Available Objective. The composition and structure of Fitoperifiton the middle and lower basin of the Cesar River and its relationship to the physical and chemical variables were characterized. Materials and methods. Sampling was conducted between February to September 2011. Samples available natural substrates (rocks, sediment and plant debris were collected, physical and chemical variables in situ and in vivo were measured. Results. 110 Morphospecies classes represented in 9 and 22 orders were found, the Bacillariophyceae had the highest density with 48% (45 species, Cyanophyceae with 35% (18 species, followed by Fragilariophyceae with 7% (9 species, Chlorophyceae 2 % (11 species, Euglenophyceae with 2% (5 species and Trebouxiophyceae Coscinodiscophyceae with 4% and 1% (respectively 4 and 3 species and finally with Ulvophyceae 0.00005% (1 species. The most representative Anabaena sp.1 Morphospecies (136.70 Cel/cm2, Oscillatoria Vaucher (129.80 Cel/cm2 and Oscillatoria sp.1 (90.20 Cel/cm2. an analysis of principal components (ACP where segmentation of some sections of the Cesar River and fitoperifiton was observed to characterize the stations for their peculiarities was made excessive growth of species in areas where they are wastewater discharges high were observed organic matter such as blue-green algae. Conclusions. The Cyanophyceae were negatively associated with oxygen according to the ACC. It was evident that the sector Puente Salguero is characterized by high concentration of organic phosphorus, plus the Fitoperifiton the Cesar River, identified this sector as the most critical point of organic contamination of the system and its influence stations downstream.

  6. Polar Lipids Analysis of Cultured Phytoplankton Reveals Significant Inter-taxa Changes, Low Influence of Growth Stage, and Usefulness in Chemotaxonomy.

    Science.gov (United States)

    Cañavate, José Pedro; Armada, Isabel; Hachero-Cruzado, Ismael

    2017-05-01

    The high lipid diversity of microalgae has been used to taxonomically differentiate phytoplankton taxa at the class level. However, important lipids such as phospholipids (PL) and betaine lipids (BL) with potential chemotaxonomy application in phytoplankton ecology have been scarcely studied. The chemotaxonomy value of PL and BL depends on their intraspecific extent of variation as microalgae respond to external changing factors. To determine such effects, lipid class changes occurring at different growth stages in 15 microalgae from ten different classes were analyzed. BL occurred in 14 species and were the less affected lipids by growth stage with diacylglyceryl-hydroxymethyl-N,N,N-trimethyl-b-alanine (DGTA) showing the highest stability. PL were more influenced by growth stage with phosphatidylcholine (PC), phosphatidylglycerol (PG), and phosphatidyletanolamine (PE) declining towards older culture stages in some species. Glycolipids were the more common lipids, and no evident age-related variability pattern could be associated to taxonomic diversity. Selecting BL and PL as descriptor variables optimally distinguished microalgae taxonomic variability at all growth stages. Principal coordinate analysis arranged species through a main tendency from diacylglyceryl-hydroxymethyl-N,N,N-trimethyl-b-alanine (DGCC) containing species (mainly dinoflagellates and haptophytes) to DGTA or PC containing species (mainly cryptophytes). Two diatom classes with similar fatty acid profiles could be distinguished from their respective content in DGTA (Bacillariophyceae) or DGCC (Mediophyceae). In green lineage classes (Trebouxiophyceae, Porphyridophyceae, and Chlorodendrophyceae), PC was a better descriptor than BL. BL and PL explained a higher proportion of microalgae taxonomic variation than did fatty acids and played a complementary role as lipid markers.

  7. Studies on the phytoplankton of the deep subalpine Lake Iseo

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    Rosario MOSELLO

    2003-08-01

    Full Text Available This paper reports the results of investigations carried out on the chemical characteristics and phytoplankton community of Lake Iseo. Samplings were performed on a monthly basis from 1998 to 2000. At least three main algal groups dominated the community throughout the study period. The large Bacillariophyceae were dominant mainly during late winter and early spring (Aulacoseira spp., Melosira varians, Asterionella formosa, with few species able to maintain occasional positive growth also during mid summer and/or autumn (Fragilaria crotonensis and Diatoma elongatum. The thermal stability of the water column and silica depletion were the main factors responsible for the decline of the large spring diatoms. The subsequent growth of Mougeotia sp. (Conjugatophyceae was favoured by its lower sinking rate and resistance to increasing grazing pressure by the dominant copepods (Copidodiaptomus steueri and cladocerans (Daphnia hyalina × galeata. Among the cyanobacteria, the greater development of Planktothrix rubescens in the autumn months, with conditions of vertical homogenisation and decreasing Zeu/Zmix ratios, was favoured by its ability to survive at low light irradiances. The temporal replacement of these three groups constitutes the main sequence of the annual phytoplankton succession in Lake Iseo. A large development of other algal groups was recorded only in one or two of the three study years (e.g. Dinophyceae and Chlorococcales. The changes observed in the annual phytoplankton development are discussed in the light of differences in the spring fertilisation of the waters, caused by differences in the depth of the layer involved in the late winter and spring vertical mixing.

  8. Paleocommunity turnover in an Early Pliocene seamount from southeastern Spain

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    García-Ramos, Diego Antonio; Zuschin, Martin

    2017-04-01

    remarkable bryoliths of Celleporaria palmata, Turbicellepora coronopus, and reteporiform colonies of Reteporella sp. in the less densely-packed beds. The cirripede Creusia phryxa is very common. Pectinid assemblages are dominated by Hinnites crispus, H. ercolanianus, Manupecten pesfelis, Mimachlamys varia and Crassadoma multistriata. Oysters are represented by Neopycnodonte and large Hyotissa. The upper part of the lower interval records clumps of Neopycnodonte sp. This is the Pliocene locality in Spain recording the highest diversity of brachiopods: Novocrania anomala, Joania cordata, Megathiris detruncata, Megerlia truncata, Terebratulina retusa, Lacazella mediterranea, Aphelesia bipartita and Terebratula calabra. The latter two species are more abundant in the middle part of the section, Terebratula forming pavements. Most common echinoids are Stylocidaris? sp., Echinocyamus, and Arbacina, while fragments of spatangoids like Ova and Spatangus are less common. Crinoid cirrals and ophiourid vertebrae are scarce. The upper interval commences with sparse rhodolith debris while at the very top complete rhodoliths are the dominant bioclasts together with pectinids. Common taxa in the lower interval decrease in abundance or disappear. Pectinids are replaced by Pecten spp. and rare Gigantopecten latissimus; Aequipecten scabrellus is most abundant in the middle part and A. opercularis dominates at the very top. Fragments of Clypeaster start to occur and Ostrea is increasingly common. Preliminary results indicate a decrease of diversity concomitant with a shallowing upward trend.

  9. Planktonic microbes in the Gulf of Maine area.

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    Li, William K W; Andersen, Robert A; Gifford, Dian J; Incze, Lewis S; Martin, Jennifer L; Pilskaln, Cynthia H; Rooney-Varga, Juliette N; Sieracki, Michael E; Wilson, William H; Wolff, Nicholas H

    2011-01-01

    In the Gulf of Maine area (GoMA), as elsewhere in the ocean, the organisms of greatest numerical abundance are microbes. Viruses in GoMA are largely cyanophages and bacteriophages, including podoviruses which lack tails. There is also evidence of Mimivirus and Chlorovirus in the metagenome. Bacteria in GoMA comprise the dominant SAR11 phylotype cluster, and other abundant phylotypes such as SAR86-like cluster, SAR116-like cluster, Roseobacter, Rhodospirillaceae, Acidomicrobidae, Flavobacteriales, Cytophaga, and unclassified Alphaproteobacteria and Gammaproteobacteria clusters. Bacterial epibionts of the dinoflagellate Alexandrium fundyense include Rhodobacteraceae, Flavobacteriaceae, Cytophaga spp., Sulfitobacter spp., Sphingomonas spp., and unclassified Bacteroidetes. Phototrophic prokaryotes in GoMA include cyanobacteria that contain chlorophyll (mainly Synechococcus), aerobic anoxygenic phototrophs that contain bacteriochlorophyll, and bacteria that contain proteorhodopsin. Eukaryotic microalgae in GoMA include Bacillariophyceae, Dinophyceae, Prymnesiophyceae, Prasinophyceae, Trebouxiophyceae, Cryptophyceae, Dictyochophyceae, Chrysophyceae, Eustigmatophyceae, Pelagophyceae, Synurophyceae, and Xanthophyceae. There are no records of Bolidophyceae, Aurearenophyceae, Raphidophyceae, and Synchromophyceae in GoMA. In total, there are records for 665 names and 229 genera of microalgae. Heterotrophic eukaryotic protists in GoMA include Dinophyceae, Alveolata, Apicomplexa, amoeboid organisms, Labrynthulida, and heterotrophic marine stramenopiles (MAST). Ciliates include Strombidium, Lohmaniella, Tontonia, Strobilidium, Strombidinopsis and the mixotrophs Laboea strobila and Myrionecta rubrum (ex Mesodinium rubra). An inventory of selected microbial groups in each of 14 physiographic regions in GoMA is made by combining information on the depth-dependent variation of cell density and the depth-dependent variation of water volume. Across the entire GoMA, an estimate for the

  10. Planktonic microbes in the Gulf of Maine area.

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    William K W Li

    Full Text Available In the Gulf of Maine area (GoMA, as elsewhere in the ocean, the organisms of greatest numerical abundance are microbes. Viruses in GoMA are largely cyanophages and bacteriophages, including podoviruses which lack tails. There is also evidence of Mimivirus and Chlorovirus in the metagenome. Bacteria in GoMA comprise the dominant SAR11 phylotype cluster, and other abundant phylotypes such as SAR86-like cluster, SAR116-like cluster, Roseobacter, Rhodospirillaceae, Acidomicrobidae, Flavobacteriales, Cytophaga, and unclassified Alphaproteobacteria and Gammaproteobacteria clusters. Bacterial epibionts of the dinoflagellate Alexandrium fundyense include Rhodobacteraceae, Flavobacteriaceae, Cytophaga spp., Sulfitobacter spp., Sphingomonas spp., and unclassified Bacteroidetes. Phototrophic prokaryotes in GoMA include cyanobacteria that contain chlorophyll (mainly Synechococcus, aerobic anoxygenic phototrophs that contain bacteriochlorophyll, and bacteria that contain proteorhodopsin. Eukaryotic microalgae in GoMA include Bacillariophyceae, Dinophyceae, Prymnesiophyceae, Prasinophyceae, Trebouxiophyceae, Cryptophyceae, Dictyochophyceae, Chrysophyceae, Eustigmatophyceae, Pelagophyceae, Synurophyceae, and Xanthophyceae. There are no records of Bolidophyceae, Aurearenophyceae, Raphidophyceae, and Synchromophyceae in GoMA. In total, there are records for 665 names and 229 genera of microalgae. Heterotrophic eukaryotic protists in GoMA include Dinophyceae, Alveolata, Apicomplexa, amoeboid organisms, Labrynthulida, and heterotrophic marine stramenopiles (MAST. Ciliates include Strombidium, Lohmaniella, Tontonia, Strobilidium, Strombidinopsis and the mixotrophs Laboea strobila and Myrionecta rubrum (ex Mesodinium rubra. An inventory of selected microbial groups in each of 14 physiographic regions in GoMA is made by combining information on the depth-dependent variation of cell density and the depth-dependent variation of water volume. Across the entire GoMA, an

  11. [Food and reproductive biology of Farlowella vittata (Siluriformes: Loricariidae) in Güejar River Basin, Orinoco, Colombia].

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    García-Alzate, Carlos A; Román-Valencia, César; Barrero, Ana M

    2012-12-01

    Neotropical fish live in streams with considerable spatial and temporal variability of their food items. Food availability depends on different factors such as discharge, channel morphology, physicochemical conditions and interactions with other species, as well as their food habits. On the other side, good food availability results in reproductive success. Because the study of those changes contributes to a better understanding of trophic interactions in fish populations, the present work describes and evaluates aspects of diet and reproduction of Farlowella vittata in Pringamosal Creek, Güejar River drainage, Orinoco River basin, Colombia. Five collecting expeditions were done during both high and low rain seasons of 2008 and 2009. Physical and chemical water parameters were measured, and fish were captured from several points along the total length of the 7km stream, to characterize their biometry and stomach contents. Our results showed that Pringamosal creek is a first order stream, about 3.5m wide and with an average depth of 1m in our study area. Dissolved oxygen values were 6.2mg/L during low water and 2.7mg/L during high water phase. The creek is classified as oligotrophic but with a tendency to eutrophication. A total of 130 fish samples were analyzed. Fishes were assigned to seven size range categories between 86.0 and 175.5mm standard length (SL). Stomach contents revealed that the diet of this species consisted mainly of algae (Bacillariophyceae) (84.6% Abundance Relative), but we observed a variation in the diet according to season; during low rainfall it feeds on phytoplankton (86.47% A.R.) and during high rainfall on zooplankton as well as plant material and organic material (0.685% A.R. and 18.83% A.R., respectively). A Kruskal-Wallis ANOVA showed statistically significant differences in food items between sexes. The condition factor (K) indicated that the species was well fed. Size at sexual maturity was 154mm SL for males and 124mm SL for

  12. Potential role of multiple carbon fixation pathways during lipid accumulation in Phaeodactylum tricornutum

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    Valenzuela Jacob

    2012-06-01

    Full Text Available Abstract Background Phaeodactylum tricornutum is a unicellular diatom in the class Bacillariophyceae. The full genome has been sequenced (P. tricornutum gene expression profiles during nutrient-deprivation and lipid-accumulation, cell cultures were grown with a nitrate to phosphate ratio of 20:1 (N:P and whole-genome transcripts were monitored over time via RNA-sequence determination. Results The specific Nile Red (NR fluorescence (NR fluorescence per cell increased over time; however, the increase in NR fluorescence was initiated before external nitrate was completely exhausted. Exogenous phosphate was depleted before nitrate, and these results indicated that the depletion of exogenous phosphate might be an early trigger for lipid accumulation that is magnified upon nitrate depletion. As expected, many of the genes associated with nitrate and phosphate utilization were up-expressed. The diatom-specific cyclins cyc7 and cyc10 were down-expressed during the nutrient-deplete state, and cyclin B1 was up-expressed during lipid-accumulation after growth cessation. While many of the genes associated with the C3 pathway for photosynthetic carbon reduction were not significantly altered, genes involved in a putative C4 pathway for photosynthetic carbon assimilation were up-expressed as the cells depleted nitrate, phosphate, and exogenous dissolved inorganic carbon (DIC levels. P. tricornutum has multiple, putative carbonic anhydrases, but only two were significantly up-expressed (2-fold and 4-fold at the last time point when exogenous DIC levels had increased after the cessation of growth. Alternative pathways that could utilize HCO3- were also suggested by the gene expression profiles (e.g., putative propionyl-CoA and methylmalonyl-CoA decarboxylases. Conclusions The results indicate that P. tricornutum continued carbon dioxide reduction when population growth was arrested and different carbon-concentrating mechanisms were used dependent upon exogenous

  13. Species-dependent silicon isotope fractionation in unialgal cultures of marine diatoms

    Science.gov (United States)

    Sutton, J. N.; Varela, D. E.; Brzezinski, M. A.; Beucher, C.

    2011-12-01

    , n=4). A distinguishing feature of the Chaetoceros genus is the production of long silica appendages called setae after mitotic cell division is complete (Rogerson et al. 1986). These results significantly contribute to our current understanding of the modern and ancient oceanic Si cycles, and will be useful in the interpretation of marine paleo-Si sedimentary records. De La Rocha, C. L., et al. (1997), Fractionation of silicon isotopes by marine diatoms during biogenic silica formation, Geochimica Et Cosmochimica Acta, 61(23), 5051-5056. Rogerson, A., et al. (1986), Growth rates and ultrastructure of siliceous setae of Chaetoceros gracilis (Bacillariophyceae), Journal Of Phycology, 22, 56-62.

  14. CARACTERIZACIÓN LIMNOLÓGICA DE HUMEDALES DE LA PLANICIE DE INUNDACIÓN DEL RÍO ORINOCO (ORINOQUÍA, COLOMBIA

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    Alvarez Juan Pablo

    2010-04-01

    Full Text Available En este estudio se desarrolló una caracterización física y química de los principales ríos, quebradas y humedales de la región aledaña a la ciudad de Puerto Carreño (Vichada, Colombia en la época de aguas altas y bajas del Río Orinoco; y una caracterización biológica durante la época de aguas bajas. La mayor parte de los sistemas presentaron pH ácido y una baja concentración de iones y nutrientes. El régimen hidrológico tuvo un impacto importante sobre los ecosistemas acuáticos: Durante el periodo de agua altas, aumentó la transparencia y la concentración de algunos nutrientes y se presentó una reducción en la conductividad y la clorofila-a. En aguas bajas, los grupos dominantes de algas fueron Bacillariophyceae y Zygnemaphyceae; la composición taxonómica del zooplancton fue común a la encontrada en otros sistemas del complejo Amazónico-Orinoqués. Las comunidades de macroinvertebrados fueron dominadas por Coleoptera, Odonata y Ephemeroptera y la mayor diversidad de grupos funcionales y de morfotipos se presentaron en sustratos de hojarasca. Los resultados sugieren que la vegetación de la ribera juega un papel muy importante en el mantenimiento de una fuente de energía y un refugio para las comunidades acuáticas durante el periodo de aguas bajas. Así mismo, la baja mineralización de estos ecosistemas los hace muy susceptibles a contaminaci

  15. Water quality and potamoplankton evaluation of the Nile River in Upper Egypt

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    Ahmed Mohamed El-Otify

    2015-06-01

    Full Text Available Aim: The composition, abundance, community structure of potamoplankton and major physical and chemical variables of the Nile water in Upper Egypt were investigated to assess its status in different seasons during 2007.MethodsWater samples were collected seasonally during 2007 from six investigated sites from variable depths at levels of 0, 2.5 and 5 m. The area of this investigation is defined as the southern 120 Km of the main stream of the Nile in Upper Egypt (24° 04’ – 25° 00’ latitudes and 32° 51’ – 32° 54’ longitudes, downstream of Aswan Old Dam.ResultsAltogether, 121 potamoplankton species, of which 85 related to phytoplankton and 36 appertaining to zooplankton were recorded. Most numerous phytoplankton were Chlorophyceae (42 species followed by Bacillariophyceae (30 species. Cyanobacteria and Dinophyceae were less numerous with only 11 and 2 species, respectively. Zooplankton species were mainly belonging to three systematic groups namely; Rotifera (24 species, Copepoda (3 species and Cladocera (9 species. Besides, other rare zooplankton including Platyhelminthes, Nemata and Ciliophora were sparsely encountered. The main hydrological conditions characterizing the investigated area include water level fluctuations (˂82 - ˃85 m above sea level, relatively high current velocity (0.8 - 1.3 m sec–1 and disposal of wastewater. Plankton populations were variably but rather weakly dependent on the major nutrients due to their excessive availability in accessible form for uptake by the producers. For phytoplankton, the community structure was categorized in relation to temperature, pH, SO42– and Mg2+. For zooplankton, the community structure was categorized in relation to conductivity as well as Mg2+. Sampling intervals were inadequate to demonstrate the existing successional pattern of the Nile potamoplankton community. Alterations in the phytoplankton community structure accompanied changes in water temperature represented

  16. Biología alimentaria y reproductiva de Farlowella vittata (Siluriformes: Loricariidae en la cuenca del río Güejar, Orinoquía, Colombia Food and reproductive biology of Farlowella vittata (Siluriformes: Loricariidae in Güejar River Basin, Orinoco, Colombia

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    Carlos A. García-Alzate

    2012-12-01

    Full Text Available Los peces de quebradas neotropicales conviven con una considerable variación espacial y temporal de sus alimentos. La disponibilidad de estos alimentos depende de diferentes factores tales como la morfología de los canales, la descarga, atributos físico-químicos y las interacciones con otras especies. Es así como estudios de los hábitos alimenticios contribuyen a la comprensión de las interacciones tróficas de las poblaciones de peces. En el presente trabajo se describen y evalúan los aspectos de la dieta y la reproducción de Farlowella vittata (Siluriformes: Loricariidae en el Arroyo Pringamosal, cuenca del río Güejar, cuenca del río Orinoco, Colombia. Se realizaron cinco expediciones de recolecta durante las temporadas de altas y bajas lluvias. Variables físicas y químicas del agua fueron medidas y los peces fueron capturados en varios puntos a lo largo de toda la cuenca. El arroyo Pringamosal es una corriente de primer orden con 3.5m de ancho y una profundidad media de 1m en el área de estudio. Valores de oxígeno disuelto son de 6.2mg/L durante bajas lluvias y 2.7mg/L durante altas lluvias, es oligotrófico con tendencia a la eutrofización. Ciento treinta ejemplares fueron analizados, 7 intervalos de tallas fueron recolectadas entre los 86.0 y 175.5mm de longitud estándar. La dieta de esta especie consiste principalmente de algas (Bacillariophyceae (84.6% AR, pero se observó una variación en la dieta de acuerdo a la temporada; en bajas lluvias se alimenta de fitoplancton (86.47% A.R. y en altas lluvias de zooplankton y material de origen vegetal y orgánico (0.685% A.R y 18.83% A.R. respectivamente, el ANDEVA de KruskalWallis mostró diferencias estadísticamente significativas de los ítems alimenticios entre sexos. El factor de condición (K indicó que la especie se encontró bien alimentada. El índice gonadosomático (RGS mostró que este pez se reproduce en aguas altas (abril-mayo. La fecundidad fue 1 819 ovocitos

  17. Estrutura e dinâmica da comunidade fitoplanctônica a jusante e montante do reservatório de Corumbá, Caldas Novas, Estado de Goiás, Brasil Structure and dynamics of the phytoplankton community downstream and upstream Corumbá reservoir, Caldas Novas, state of Goiás, Brazil

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    Sueli Train

    2001-05-01

    Full Text Available O fitoplâncton desempenha um importante papel na teia trófica de ambientes lóticos; no entanto, estudos sobre o potamoplâncton no Brasil são ainda escassos. O presente trabalho visa a caracterizar a comunidade fitoplanctônica, nas estações a montante e jusante do reservatório de Corumbá, Estado de Goiás, e identificar as principais variáveis ambientais que influenciam sua estrutura. Foram realizadas coletas mensais, a subsuperfície, em 3 estações, no período de novembro de 1996 a novembro de 1997, e, bimestrais de janeiro de 1998 a maio de 1999. Foram analisados os padrões de distribuição do fitoplâncton em relação a alguns fatores limnológicos: temperatura da água, vazão, turbidez, condutividade elétrica, fósforo solúvel reativo, íon amônio, nitrato e nitrogênio Kjeldahl total, utilizando-se análise de correspondência canônica. Foram identificados 162 táxons. As classes Cyanophyceae e Bacillariophyceae foram as mais abundantes, sendo responsáveis pelos picos de densidade registrados. Durante o período de estudo, a maior densidade fitoplanctônica (28.313 ind.ml-1 foi registrada no rio Corumbá a jusante do reservatório, com dominância da diatomácea Achnanthes minutissima. Cylindrospermopsis raciborskii, cianoprocariota heterocitada, apresentou elevadas abundâncias nas estações a montante do reservatório, no período de seca. As variações observadas mostraram uma clara sazonalidade relacionada ao ciclo hidrológico, sendo que as menores densidades fitoplanctônicas ocorreram no período de maior vazão, enquanto que os máximos de abundância foram registrados durante reduzida vazão. Assim, a dinâmica da comunidade fitoplanctônica foi fortemente determinada pela vazão do rio Corumbá, temperatura da água e concentração de nutrientesAlthough phytoplankton plays an important role in the trophic web of lotic environments, studies on potamoplankton in Brazil are still scarce. The present study

  18. Structural and successional variability of periphytic algal community in a Amazonian lake during the dry and rainy season (Rio Branco, Acre Variação estrutural e sucessional da comunidade de algas perifíticas em lago amazônico durante o período seco e chuvoso

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    Raquel C.S França

    2011-01-01

    Full Text Available The colonization process and successional patterns of a periphytic algal community were evaluated in a Amazonian Viveiro Lake (Rio Branco, Acre, Brazil. Sampling was performed over a period of 35 days; at four-day intervals for 20 days, and then at five-day intervals. Water sampling for physical, chemical and biological analyses was done during the dry and rainy season. Glass slides were used as artificial substrates for periphyton colonization. The structural community was evaluated through population density, algae class, diversity indices and descriptive species. Species richness, diversity and evenness increased as succession progressed. While density of Bacillariophyceae, Euglenophyceae and Zygnemaphyceae increased with succession, Cyanobacteria remained dominant. Synechocystis aquatilis, Synechocystis diplococcus and Navicula pseudolanceolata were the main descriptive species in both the dry and rainy season. Cymbela tumida, Frustulia rhomboides, Trachelomonas lacustris and Closterium acicularis was correlated with an increase in hydrologic level during the rainy season. Conversely, the density of Chlamydomonas sp., Chroomonas nordstedtii, Trachelomonas volvocinopsis, Trachelomonas volvocina and Synechococcus linearis was correlated with an increase in water transparency during the dry season. In general, the periphytic algal community showed high diversity and species richness independent of season. Season also had little influence on representation of algae class and main descriptive species. However, successional patterns varied by season, and changes in hydrologic levels acted directly on the succession path of periphytic algae. More research on periphyton dynamics is needed to improve our understanding of tropical lake ecosystems, especially in Amazonian.A colonização e o modelo sucessional da comunidade de algas perifíticas foram avaliados no amazônico Lago do Viveiro (Rio Branco, Acre, Brasil. Amostragens foram realizadas no per

  19. Biología alimentaria y reproductiva de Farlowella vittata (Siluriformes: Loricariidae en la cuenca del río Güejar, Orinoquía, Colombia

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    Carlos A. García-Alzate

    2012-12-01

    Full Text Available Los peces de quebradas neotropicales conviven con una considerable variación espacial y temporal de sus alimentos. La disponibilidad de estos alimentos depende de diferentes factores tales como la morfología de los canales, la descarga, atributos físico-químicos y las interacciones con otras especies. Es así como estudios de los hábitos alimenticios contribuyen a la comprensión de las interacciones tróficas de las poblaciones de peces. En el presente trabajo se describen y evalúan los aspectos de la dieta y la reproducción de Farlowella vittata (Siluriformes: Loricariidae en el Arroyo Pringamosal, cuenca del río Güejar, cuenca del río Orinoco, Colombia. Se realizaron cinco expediciones de recolecta durante las temporadas de altas y bajas lluvias. Variables físicas y químicas del agua fueron medidas y los peces fueron capturados en varios puntos a lo largo de toda la cuenca. El arroyo Pringamosal es una corriente de primer orden con 3.5m de ancho y una profundidad media de 1m en el área de estudio. Valores de oxígeno disuelto son de 6.2mg/L durante bajas lluvias y 2.7mg/L durante altas lluvias, es oligotrófico con tendencia a la eutrofización. Ciento treinta ejemplares fueron analizados, 7 intervalos de tallas fueron recolectadas entre los 86.0 y 175.5mm de longitud estándar. La dieta de esta especie consiste principalmente de algas (Bacillariophyceae (84.6% AR, pero se observó una variación en la dieta de acuerdo a la temporada; en bajas lluvias se alimenta de fitoplancton (86.47% A.R. y en altas lluvias de zooplankton y material de origen vegetal y orgánico (0.685% A.R y 18.83% A.R. respectivamente, el ANDEVA de KruskalWallis mostró diferencias estadísticamente significativas de los ítems alimenticios entre sexos. El factor de condición (K indicó que la especie se encontró bien alimentada. El índice gonadosomático (RGS mostró que este pez se reproduce en aguas altas (abril-mayo. La fecundidad fue 1 819 ovocitos

  20. Microalgal diversity in relation to the physicochemical parameters of some Industrial sites in Mangalore, South India.

    Science.gov (United States)

    Miranda, Jyothi; Krishnakumar, G

    2015-11-01

    This study is undertaken to understand the microalgal species composition, diversity, abundance and their association with the polluted sites of an industrial area. The microalgae and the wastewater samples collected from these sites were preserved and analysed using standard methods. One hundred and eight species of the microalgae, belonging to Cyanophyceae, Chlorophyceae, Euglenophyceae, Bacillariophyceace and Desmidaceae, were identified. Of these, the members of Cyanophyceae formed the dominant flora. It was observed that the family Oscillatoriaceae was the most diverse family. In this family, the most diverse genus was found to be the Oscillatoria, with 13 species. Further, the abundance of Oscillatoria princeps indicated that these species are tolerant to the pollution and therefore considered as the 'marker species' of the habitat. The abundance of the Cyanophyceae in these sites was found to be due to the favourable contents of the oxidizable organic matter and the presence of the nutrients, such as the nitrates and the phosphates, in abundance, with less dissolved oxygen. The lesser percentage of the Bacillariophyceae (14%), and the negligible number of the euglenoids (2%) indicated that the sites were rich in the inorganic pollutants and poor in the organic pollutants. The range of Shannon diversity indices was found between 2.10 and 3.50, while the dominance index was found between 0.03 and 0.14, the species evenness between 0.73 and 0.93 and the Margalef index between 1.8 and 6.3. The diversity indices indicated that there is light to moderate level of pollution in the studied sites, with moderate diversity level. The principal component analysis (PCA) of the physicochemical parameters identified the four possible groups, which were responsible for the data structure, explaining the 74% of the total variance of the data set. In the PCA performed using all the variables, the first principal component showed the positive correlation with the total

  1. Phytoplankton of the North Sea and its dynamics: A review

    Science.gov (United States)

    Reid, P. C.; Lancelot, C.; Gieskes, W. W. C.; Hagmeier, E.; Weichart, G.

    Phytoplankton is the major contributor to algal biomass and primary production of the North Sea, although crops of macroalgae can locally be up to 2000 g C.m -2 along the coast of the U.K. and Norway, and microphytobenthos dominates production in the shallow tidal flat areas bordering the coasts of England, the Netherlands, Germany and Denmark. Data collected since 1932 during the Continuous Plankton Recorder Survey show consistent patterns of geographical, seasonal and annual variation in the distribution of phytoplankton and its major taxonomic components. There is a trend of increased colouration in Recorder silks in the southern North Sea until approximately 1975 since when Colour levels (assumed to be indicative of algal biomass) have declined. In the eutrophic Dutch Wadden Sea the algal crop continued to increase; in Dutch coastal North Sea waters a trend of biomass increase reversed since 1984, apparently due to a reduction in Rhine river outflow. Long-term observations made at Helgoland since the 60's also show trends of increasing nutrients and phytoplankton biomass only to 1984. Adverse effects such as deoxygenation, foam formation and toxin production have been linked to mass concentrations of algae known as blooms. There is no evidence from existing reports for an increase in their frequency, although some years stand out with larger numbers. Occurrence of blooms can partly be explained by hydrographic conditions. More than 30 taxa are recognised as occurring in bloom proportions in the North Sea, approximately one third of which can be toxic. The crop of Bacillariophyceae (diatoms) is not likely to increase with eutrophication due to silicate limitation. An extensive subsurface maximum of armoured dinoflagellates, its abundance gouverned by hydrographic conditions, is the most characteristic feature of the central and northern North Sea in the summer months. Abundance, sometimes dominance, of picoplankton and of species that are not readily detected by