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Sample records for algal species composition

  1. [Parametric control of the yield characteristics and species composition dynamics of algal poly-culture].

    PubMed

    Nefedova, E L; Levinskikh, M A; Sychev, V N

    2006-01-01

    There are several experimental models of biological life support systems (BLSS) designed to incorporate a chlorella pool. These BLSS can be optimized if populated by algal associations that could take up more functions within the closed cycling system than a single alga species. Introduction of a Spirulina and Chlamydomonas poly-culture with differing in gas exchange and biochemical composition resulted in a tighter closure of linkages within the system. The factors determining the size of a species population in intensive continuous poly-cultures are, first and foremost, pH and suspension flow rate. Experimental testing of this supposition brought us to the conclusion that parametric control of alga productivity and species composition dynamics makes it possible to create a steady intensive poly-culture as part of the LSS for humans. Flow rate and pH can be the parameters for control of the Spirulina and Chlamydomonas populations during continuous cultivation of this poly-culture. PMID:17357628

  2. Algal growth and species composition under experimental control of herbivory, phosphorus and coral abundance in Glovers Reef, Belize.

    PubMed

    McClanahan, T R; Cokos, B A; Sala, E

    2002-06-01

    The proliferation of algae on disturbed coral reefs has often been attributed to (1) a loss of large-bodied herbivorous fishes, (2) increases in sea water nutrient concentrations, particularly phosphorus, and (3) a loss of hard coral cover or a combination of these and other factors. We performed replicated small-scale caging experiments in the offshore lagoon of Glovers Reef atoll, Belize where three treatments had closed-top (no large-bodied herbivores) and one treatment had open-top cages (grazing by large-bodied herbivores). Closed-top treatments simulated a reduced-herbivory situation, excluding large fishes but including small herbivorous fishes such as damselfishes and small parrotfishes. Treatments in the closed-top cages included the addition of high phosphorus fertilizer, live branches of Acropora cervicornis and a third unmanipulated control treatment. Colonization, algal biomass and species composition on dead A. palmata "plates" were studied weekly for 50 days in each of the four treatments. Fertilization doubled the concentration of phosphorus from 0.35 to 0.77 microM. Closed-top cages, particularly the fertilizer and A. cervicornis additions, attracted more small-bodied parrotfish and damselfish than the open-top cages such that there was moderate levels of herbivory in closed-top cages. The open-top cages did, however, have a higher abundance of the chemically and morphologically defended erect algal species including Caulerpa cupressoides, Laurencia obtusa, Dictyota menstrualis and Lobophora variegata. The most herbivore-resistant calcareous green algae (i.e. Halimeda) were, however, uncommon in all treatments. Algal biomass increased and fluctuated simultaneously in all treatments over time, but algal biomass, as measured by wet, dry and decalcified weight, did not differ greatly between the treatments with only marginally higher biomass (p < 0.06) in the fertilized compared to open-top cages. Algal species composition was influenced by all

  3. Biochemical composition of three algal species proposed as food for captive freshwater mussels

    USGS Publications Warehouse

    Gatenby, C.M.; Orcutt, D.M.; Kreeger, D.A.; Parker, B.C.; Jones, V.A.; Neves, R.J.

    2003-01-01

    To identify potential diets for rearing captive freshwater mussels, the protein, carbohydrate (CHO), and lipid contents of two green algae, Neochloris oleoabundans, Bracteacoccus grandis, and one diatom, Phaeodactylum tricornutum, were compared at different growth stages. The fatty acid and sterol composition were also identified. Protein was greatest (55-70%) for all species at late log growth stage (LL), and declined in late stationary (LS) growth. CHO was greatest at LS stage for all species (33.9-56.4% dry wt). No significant change in lipid levels occurred with growth stage, but tended to increase in N. oleoabundans. Mean lipid content differed significantly in the order: N. oleoabundans > P. tricornutum > B. grandis. Total fatty acids (TFA) were higher at LS stage compared to other stages in the two green algae, and stationary stage in the diatom. Mean unsaturated fatty acids (UFA) as %TFA was significantly higher in N. oleoabundans than the other species. The green algae contained high percentages of C-18 polyunsaturated fatty acids (PUFAs), while the diatom was abundant in C-16 saturated and mono-unsaturated fatty acids and C-20 PUFA fatty acids. Growth stage had no effect on sterol concentration of any species. B. grandis showed significantly higher sterol levels than the other species except P. tricornutum at S stage. B. grandis was characterized by predominantly ??5, C-29 sterols, while N. oleoabundans synthesized ??5,7, ??5,7,22, and ??7, C-28 sterols. P. tricornutum produced primarily a ??5,22, C-28 sterol, and a small amount of a ??7,22, C-28 sterol.

  4. Identification of physical parameters controlling the dominance of algal species in a subtropical reservoir.

    PubMed

    Chien, Y C; Wu, S C; Wu, J T

    2009-01-01

    Eutrophication is a serious problem of water resource management in Taiwan. The occurrence of annoying algal species as well as abnormally abundant algal mass threatens the quality of water supply. The growth and decline of a specific phytoplankton species are affected by environmental factors, including light, nutrients, temperature, etc. There have been many investigations on the effects of individual factors on the abundance and composition of algal populations. However, many analyses on the effects of environmental factors, especially the concentration of nutrients, on phytoplankton failed to identify the controlling factors on the dynamic change of the phytoplankton species. This study used statistical methods to isolate the effect of seasons on the phytoplankton growth and searched for the relationships between the nutrient concentrations and the abundance of different algal species in Feitsui Reservoir based on the data obtained from 1995 to 2003. We found that the dynamic change of dominance of some species of phytoplankton was strongly related to the seasonal factors. The controlling factors of the survival of an algal species were the settling and mobility of the phytoplankton, the mixing depth and the vertical mixing strength of the water bodies. According to our preliminary findings, the influence of physical factors, varying seasonally, outweighs the influence of nutrients on the algal species composition in Feitsui Reservoir in Taiwan. PMID:19809140

  5. Resolving Mixed Algal Species in Hyperspectral Images

    PubMed Central

    Mehrubeoglu, Mehrube; Teng, Ming Y.; Zimba, Paul V.

    2014-01-01

    We investigated a lab-based hyperspectral imaging system's response from pure (single) and mixed (two) algal cultures containing known algae types and volumetric combinations to characterize the system's performance. The spectral response to volumetric changes in single and combinations of algal mixtures with known ratios were tested. Constrained linear spectral unmixing was applied to extract the algal content of the mixtures based on abundances that produced the lowest root mean square error. Percent prediction error was computed as the difference between actual percent volumetric content and abundances at minimum RMS error. Best prediction errors were computed as 0.4%, 0.4% and 6.3% for the mixed spectra from three independent experiments. The worst prediction errors were found as 5.6%, 5.4% and 13.4% for the same order of experiments. Additionally, Beer-Lambert's law was utilized to relate transmittance to different volumes of pure algal suspensions demonstrating linear logarithmic trends for optical property measurements. PMID:24451451

  6. Near- and mid-infrared spectroscopic determination of algal composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to investigate the feasibility of using near-infrared reflectance spectroscopy (NIRS) and mid-infrared reflectance spectroscopy (MIRS) to determine the composition of algal samples. We assayed a set of algal biomass samples (n=117), collected from algae turf scrubber...

  7. Depth distribution of algal species on the deep insular fore reef at Lee Stocking Island, Bahamas

    NASA Astrophysics Data System (ADS)

    Aponte, Nilda E.; Ballantine, David L.

    2001-10-01

    Deep-water benthic algal composition and cover were studied with a submersible on the deep fore reef of Lee Stocking Island, Bahamas, from 45 to 150 m. Algal cover decreased from 57% to 16% over this depth range. Although there was substantial overlap in depth distributions, different species or groups of species dominated benthic cover at different depths. Lobophora and Halimeda copiosa co-dominated the fore reef from 45 to 60 m. A Corallinales/ Peyssonnelia group was abundant from 60 to 120 m. The Corallinales/ Peyssonnelia group shared dominance with Ostreobium between 90 and 120 m. Ostreobium was the only alga observed below 150 m and remained abundant below 200 m. Movement of sand down the fore reef is recognized as having substantial influence on algal cover.

  8. Metabolism of mutagenic polycyclic aromatic hydrocarbons by photosynthetic algal species.

    PubMed

    Schoeny, R; Cody, T; Warshawsky, D; Radike, M

    1988-02-01

    Polycyclic aromatic hydrocarbons (PAH) known to produce carcinogenic and mutagenic effects have been shown to contaminate waters, sediments and soils. While it is accepted that metabolites of these compounds are responsible for most of their biological effects in mammals, their metabolism, and to a large extent their bioactivity, in aquatic plants have not been explored. Cultures of photosynthetic algal species were assayed for their ability to metabolize benzo[a]pyrene (BaP), a carcinogenic PAH under conditions which either permitted (white light) or disallowed (gold light) photooxidation of the compound. Growth of Selenastrum capricornutum, a fresh-water green alga, was completely inhibited when incubated in white light with 160 micrograms BaP/l medium. By contrast concentrations at the upper limit of BaP solubility in aqueous medium had no effect on algal growth when gold light was used. BaP quinones and phenol derivatives were found to inhibit growth of Selenastrum under white light incubation. BaP phototoxicity and metabolism were observed to be species-specific. All 3 tested species of the order Chlorococcales were growth-inhibited by BaP in white light whereas neither the green alga Chlamydomonas reinhardtii nor a blue-green, a yellow-green or an euglenoid alga responded in this fashion. Assays of radiolabeled BaP metabolism in Selenastrum showed that the majority of radioactivity associated with BaP was found in media as opposed to algal cell pellets, that the extent of metabolism was BaP concentration dependent, and that the proportion of various metabolites detected was a function of the light source. After gold light incubation, BaP diols predominated while after white light treatment at equal BaP concentrations, the 3,6-quinone was found in the highest concentration. Extracted material from algal cell pellets and from media was tested for mutagenicity in a forward mutation suspension assay in Salmonella typhimurium using resistance to 8-azaguanine for

  9. The distribution and impacts of harmful algal bloom species in eastern boundary upwelling systems

    NASA Astrophysics Data System (ADS)

    Trainer, V. L.; Pitcher, G. C.; Reguera, B.; Smayda, T. J.

    2010-04-01

    Comparison of harmful algal bloom (HAB) species in eastern boundary upwelling systems, specifically species composition, bloom densities, toxin concentrations and impacts are likely to contribute to understanding these phenomena. We identify and describe HABs in the California, Canary, Benguela and Humboldt Current systems, including those that can cause the poisoning syndromes in humans called paralytic shellfish poisoning (PSP), diarrhetic shellfish poisoning (DSP), and amnesic shellfish poisoning (ASP), as well as yessotoxins, ichthyotoxins, and high-biomass blooms resulting in hypoxia and anoxia. Such comparisons will allow identification of parameters, some unique to upwelling systems and others not, that contribute to the development of these harmful blooms.

  10. Seasonal patterns in stream periphyton fatty acids and community benthic algal composition in six high quality headwater streams

    USGS Publications Warehouse

    Honeyfield, Dale C.; Maloney, Kelly O.

    2015-01-01

    Fatty acids are integral components of periphyton and differ among algal taxa. We examined seasonal patterns in periphyton fatty acids in six minimally disturbed headwater streams in Pennsylvania’s Appalachian Mountains, USA. Environmental data and periphyton were collected across four seasons for fatty acid and algal taxa content. Non-metric multidimensional scaling ordination suggested significant seasonal differences in fatty acids; an ordination on algal composition revealed similar seasonal patterns, but with slightly weaker separation of summer and fall. Summer and fall fatty acid profiles were driven by temperature, overstory cover, and conductivity and winter profiles by measures of stream size. Ordination on algal composition suggested that summer and fall communities were driven by overstory and temperature, whereas winter communities were driven by velocity. The physiologically important fatty acid 18:3ω6 was highest in summer and fall. Winter samples had the highest 20:3ω3. Six saturated fatty acids differed among the seasons. Periphyton fatty acids profiles appeared to reflect benthic algal species composition. This suggests that periphyton fatty acid composition can be useful in characterizing basal food resources and stream water quality.

  11. Algal Species and Light Microenvironment in a Low-pH, Geothermal Microbial Mat Community

    PubMed Central

    Ferris, M. J.; Sheehan, K. B.; Kühl, M.; Cooksey, K.; Wigglesworth-Cooksey, B.; Harvey, R.; Henson, J. M.

    2005-01-01

    Unicellular algae are the predominant microbial mat-forming phototrophs in the extreme environments of acidic geothermal springs. The ecology of these algae is not well known because concepts of species composition are inferred from cultivated isolates and microscopic observations, methods known to provide incomplete and inaccurate assessments of species in situ. We used sequence analysis of 18S rRNA genes PCR amplified from mat samples from different seasons and different temperatures along a thermal gradient to identify algae in an often-studied acidic (pH 2.7) geothermal creek in Yellowstone National Park. Fiber-optic microprobes were used to show that light for algal photosynthesis is attenuated to <1% over the 1-mm surface interval of the mat. Three algal sequences were detected, and each was present year-round. A Cyanidioschyzon merolae sequence was predominant at temperatures of ≥49°C. A Chlorella protothecoides var. acidicola sequence and a Paradoxia multisita-like sequence were predominant at temperatures of ≤39°C. PMID:16269755

  12. Algal species and light microenvironment in a low-pH, geothermal microbial mat community.

    PubMed

    Ferris, M J; Sheehan, K B; Kühl, M; Cooksey, K; Wigglesworth-Cooksey, B; Harvey, R; Henson, J M

    2005-11-01

    Unicellular algae are the predominant microbial mat-forming phototrophs in the extreme environments of acidic geothermal springs. The ecology of these algae is not well known because concepts of species composition are inferred from cultivated isolates and microscopic observations, methods known to provide incomplete and inaccurate assessments of species in situ. We used sequence analysis of 18S rRNA genes PCR amplified from mat samples from different seasons and different temperatures along a thermal gradient to identify algae in an often-studied acidic (pH 2.7) geothermal creek in Yellowstone National Park. Fiber-optic microprobes were used to show that light for algal photosynthesis is attenuated to < 1% over the 1-mm surface interval of the mat. Three algal sequences were detected, and each was present year-round. A Cyanidioschyzon merolae sequence was predominant at temperatures of > or = 49 degrees C. A Chlorella protothecoides var. acidicola sequence and a Paradoxia multisita-like sequence were predominant at temperatures of < or = 39 degrees C. PMID:16269755

  13. Mass cultivation of various algal species and their evaluation as a potential candidate for lipid production.

    PubMed

    Sharif, Nadia; Munir, Neelma; Saleem, Faiza; Aslam, Farheen; Naz, Shagufta

    2015-01-01

    Microalgae have been proposed as a promising source for biodiesel production. Focusing on algal strains for biodiesel production, efforts should be made to search new strains. Experiments were carried out to investigate the effects of growth parameters (nutrients, pH, light, aeration and temperature) and the oil percentage of eight algal strains (Chlorella sp., Cladophora sp., Hydrodictylium sp., Oedogonium sp., Oscillatoria sp., Spirogyra sp., Stigeocolonium sp., Ulothrix sp.). Results show that 6.5-7.5 is the optimum pH for the growth of all algal species. Temperature showed a greater variation (25°40°C). Ulothrix sp. gave more biomass productivity and is the most suitable strain for biodiesel production due to higher oil percentage (62%). Least biomass production was observed for Stigeocolonium sp. and least oil content was obtained from Hydrodictylium sp. It was observed that among these eight algal strains for biodiesel production, Ulothrix and Chlorella are the most promising algae species. PMID:25675371

  14. Strain, biochemistry, and cultivation-dependent measurement variability of algal biomass composition.

    PubMed

    Laurens, Lieve M L; Van Wychen, Stefanie; McAllister, Jordan P; Arrowsmith, Sarah; Dempster, Thomas A; McGowen, John; Pienkos, Philip T

    2014-05-01

    Accurate compositional analysis in biofuel feedstocks is imperative; the yields of individual components can define the economics of an entire process. In the nascent industry of algal biofuels and bioproducts, analytical methods that have been deemed acceptable for decades are suddenly critical for commercialization. We tackled the question of how the strain and biochemical makeup of algal cells affect chemical measurements. We selected a set of six procedures (two each for lipids, protein, and carbohydrates): three rapid fingerprinting methods and three advanced chromatography-based methods. All methods were used to measure the composition of 100 samples from three strains: Scenedesmus sp., Chlorella sp., and Nannochloropsis sp. The data presented point not only to species-specific discrepancies but also to cell biochemistry-related discrepancies. There are cases where two respective methods agree but the differences are often significant with over- or underestimation of up to 90%, likely due to chemical interferences with the rapid spectrophotometric measurements. We provide background on the chemistry of interfering reactions for the fingerprinting methods and conclude that for accurate compositional analysis of algae and process and mass balance closure, emphasis should be placed on unambiguous characterization using methods where individual components are measured independently. PMID:24556245

  15. Selective algicidal action of peptides against harmful algal bloom species.

    PubMed

    Park, Seong-Cheol; Lee, Jong-Kook; Kim, Si Wouk; Park, Yoonkyung

    2011-01-01

    Recently, harmful algal bloom (HAB), also termed "red tide", has been recognized as a serious problem in marine environments according to climate changes worldwide. Many novel materials or methods to prevent HAB have not yet been employed except for clay dispersion, in which can the resulting sedimentation on the seafloor can also cause alteration in marine ecology or secondary environmental pollution. In the current study, we investigated that antimicrobial peptide have a potential in controlling HAB without cytotoxicity to harmless marine organisms. Here, antimicrobial peptides are proposed as new algicidal compounds in combating HAB cells. HPA3 and HPA3NT3 peptides which exert potent antimicrobial activity via pore forming action in plasma membrane showed that HPA3NT3 reduced the motility of algal cells, disrupted their plasma membrane, and induced the efflux of intracellular components. Against raphidoflagellate such as Heterosigma akashiwo, Chattonella sp., and C. marina, it displayed a rapid lysing action in cell membranes at 1~4 µM within 2 min. Comparatively, its lysing effects occurred at 8 µM within 1 h in dinoflagellate such as Cochlodium polykrikoides, Prorocentrum micans, and P. minimum. Moreover, its lysing action induced the lysis of chloroplasts and loss of chlorophyll a. In the contrary, this peptide was not effective against Skeletonema costatum, harmless algal cell, even at 256 µM, moreover, it killed only H. akashiwo or C. marina in co-cultivation with S. costatum, indicating to its selective algicidal activity between harmful and harmless algal cells. The peptide was non-hemolytic against red blood cells of Sebastes schlegeli, the black rockfish, at 120 µM. HAB cells were quickly and selectively lysed following treatment of antimicrobial peptides without cytotoxicity to harmless marine organisms. Thus, the antibiotic peptides examined in our study appear to have much potential in effectively controlling HAB with minimal impact on marine

  16. Evaluation of different algal species sensitivity to mercury and metolachlor by PAM-fluorometry.

    PubMed

    Juneau, P; Dewez, D; Matsui, S; Kim, S G; Popovic, R

    2001-11-01

    In this study, the pulse-amplitude-modulation (PAM)-fluorometric method was used to evaluate the difference in the sensitivity to mercury (Hg) and metolachlor of six algal species: Ankistrodesmus falcatus, Selenastrum capricornutum, Chlorella vulgaris, Nannoplankton (PLS), Microcystis aeruginosa and Pediastrum biwae. We found that the fluorescence parameters (phiM, the maximal photosystem II (PSII) quantum yield, phi'M, the operational PSII quantum yield at steady state of electron transport, Q(P), the photochemical quenching value, and Q(N), the non-photochemical quenching value) were appropriate indicators for inhibitory effects of mercury but only phi'M and Q(N) were useful for metolachlor. The examined algal species showed very different levels of sensitivity to the effect of Hg and of metolachlor. The most sensitive species to Hg and metolachlor were respectively M. aeruginosa and A. falcatus, while the least sensitive were C. vulgaris and P. biwae. We interpreted these differences by the action mode of pollutants and by the different metabolism properties and morphological characteristics between algal species. These results related to fluorescence parameters may offer useful tool to be used in bioassay for different pollutants. Heterogeneous algal sensitivity to the same pollutant suggests the need to use a battery of species to evaluate the effects of mixtures of pollutants in aquatic systems. PMID:11680755

  17. Chemical composition influence of cement based mortars on algal biofouling

    NASA Astrophysics Data System (ADS)

    Estelle, Dalod; Alexandre, Govin; Philippe, Grosseau; Christine, Lors; René, Guyonnet; Denis, Damidot

    2013-04-01

    The main cause of building-facade biodegradation is the growth of microorganisms. This phenomenon depends on several parameters such as the geographical situation, the environmental conditions and the surface state of the substrate. Several researches have been devoted to the study of the effect of porosity and roughness on the biofouling of stones and mortars. However, none of them have addressed the influence of the mortar chemistry on the microorganism growth kinetic. The main objective of this study is to highlight the influence of the mortar chemistry in relationship with its physical properties on biological weathering. Earlier work showed a good resistance of Calcium Aluminate Cements to biodeterioration by acidogenic bacteria (Thiobacillus) and fungi (Alternaria alternata, Aspergillus Niger and Coniosporium uncinatum). In order to characterize the influence of the mortar chemistry on biofouling, two Portland cements and two alumina cements are used. Among micro-organisms able to grow, green algae are most involved in the aesthetic deterioration of facades. Indeed, they can colonize any type of media and can be a source of nutrients for other micro-organisms such as fungi. The green algae Klebsormidium flaccidum is chosen because of its representativeness. It is indeed the species the most frequently identified and isolated from samples taken on sites. The biofouling kinetic is followed on samples exposed outdoor and on samples tested in a laboratory bench which consists in spraying an algae culture on mortar specimens. The results obtained by in situ trials are compared with the results obtained on the laboratory bench. The microorganism growth kinetic is measured by image analysis. To improve the detection of algae on the surface of the cementitious samples, the raw image is converted in the YIQ color space. Y, I and Q correspond respectively to luminance, in-phase, and quadrature. On the Q channel, the areas covered by algae and the areas of clean mortar

  18. Comparing new and conventional methods to estimate benthic algal biomass and composition in freshwaters.

    PubMed

    Kahlert, Maria; McKie, Brendan G

    2014-11-01

    We compared conventional microscope-based methods for quantifying biomass and community composition of stream benthic algae with output obtained for these parameters from a new instrument (the BenthoTorch), which measures fluorescence of algal pigments in situ. Benthic algae were studied in 24 subarctic oligotrophic (1.7-26.9, median 7.2 μg total phosphorus L(-1)) streams in Northern Sweden. Readings for biomass of the total algal mat, quantified as chlorophyll a, did not differ significantly between the BenthoTorch (median 0.52 μg chlorophyll a cm(-2)) and the conventional method (median 0.53 μg chlorophyll a cm(-2)). However, quantification of community composition of the benthic algal mat obtained using the BenthoTorch did not match those obtained from conventional methods. The BenthoTorch indicated a dominance of diatoms, whereas microscope observations showed a fairly even distribution between diatoms, blue-green algae (mostly nitrogen-fixing) and green algae (mostly large filamentous), and also detected substantial biovolumes of red algae in some streams. These results most likely reflect differences in the exact parameters quantified by the two methods, as the BenthoTorch does not account for variability in cell size and the presence of non-chlorophyll bearing biomass in estimating the proportion of different algal groups, and does not distinguish red algal chlorophyll from that of other algal groups. Our findings suggest that the BenthoTorch has utility in quantifying biomass expressed as μg chlorophyll a cm(-2), but its output for the relative contribution of different algal groups to benthic algal biomass should be used with caution. PMID:25277172

  19. HPLC pigment profiles of 31 harmful algal bloom species isolated from the coastal sea areas of China

    NASA Astrophysics Data System (ADS)

    Liu, Shuxia; Yao, Peng; Yu, Zhigang; Li, Dong; Deng, Chunmei; Zhen, Yu

    2014-12-01

    Chemotaxonomy based on diagnostic pigments is now a routine tool for macroscopic determination of the composition and abundance of phytoplankton in various aquatic environments. Since the taxonomic capability of this method depends on the relationships between diagnostic pigments and chlorophyll a of classified groups, it is critical to calibrate it by using pigment relationships obtained from representative and/or dominant species local to targeted investigation area. In this study, pigment profiles of 31 harmful algal bloom (HAB) species isolated from the coastal sea areas of China were analyzed with high performance liquid chromatography (HPLC). Pigment compositions, cellular pigment densities and ratios of pigments to chlorophyll a were determined and calculated. Among all these species, 25 kinds of pigments were detected, of which fucoxanthin, peridinin, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, violaxanthin, and antheraxanthin were diagnostic pigments. Cellular pigment density was basically independent of species and environmental conditions, and therefore was recommended as a bridge to compare the results of HPLC-CHEMTAX technique with the traditional microscopy method. Pigment ratios of algal species isolated from the coast of China, especially the diagnostic pigment ratios, were higher than those from other locations. According to these results, pigment ratio ranges of four classes of phytoplankton common off the coast of China were summarized for using in the current chemotaxonomic method. Moreover, the differences of pigments ratios among different species under the same culturing conditions were consistent with their biological differences. Such differences have the potential to be used to classify the phytoplankton below class, which is meaningful for monitoring HABs by HPLC-CHEMTAX.

  20. Bacilysin from Bacillus amyloliquefaciens FZB42 Has Specific Bactericidal Activity against Harmful Algal Bloom Species

    PubMed Central

    Wu, Liming; Wu, Huijun; Chen, Lina; Xie, Shanshan; Zang, Haoyu; Borriss, Rainer

    2014-01-01

    Harmful algal blooms, caused by massive and exceptional overgrowth of microalgae and cyanobacteria, are a serious environmental problem worldwide. In the present study, we looked for Bacillus strains with sufficiently strong anticyanobacterial activity to be used as biocontrol agents. Among 24 strains, Bacillus amyloliquefaciens FZB42 showed the strongest bactericidal activity against Microcystis aeruginosa, with a kill rate of 98.78%. The synthesis of the anticyanobacterial substance did not depend on Sfp, an enzyme that catalyzes a necessary processing step in the nonribosomal synthesis of lipopeptides and polyketides, but was associated with the aro gene cluster that is involved in the synthesis of the sfp-independent antibiotic bacilysin. Disruption of bacB, the gene in the cluster responsible for synthesizing bacilysin, or supplementation with the antagonist N-acetylglucosamine abolished the inhibitory effect, but this was restored when bacilysin synthesis was complemented. Bacilysin caused apparent changes in the algal cell wall and cell organelle membranes, and this resulted in cell lysis. Meanwhile, there was downregulated expression of glmS, psbA1, mcyB, and ftsZ—genes involved in peptidoglycan synthesis, photosynthesis, microcystin synthesis, and cell division, respectively. In addition, bacilysin suppressed the growth of other harmful algal species. In summary, bacilysin produced by B. amyloliquefaciens FZB42 has anticyanobacterial activity and thus could be developed as a biocontrol agent to mitigate the effects of harmful algal blooms. PMID:25261512

  1. Investigation of severe UF membrane fouling induced by three marine algal species.

    PubMed

    Merle, Tony; Dramas, Laure; Gutierrez, Leonardo; Garcia-Molina, Veronica; Croué, Jean-Philippe

    2016-04-15

    Reducing membrane fouling caused by seawater algal bloom is a challenge for regions of the world where most of their freshwater is produced by seawater desalination. This study aims to compare ultrafiltration (UF) fouling potential of three ubiquitous marine algal species cultures (i.e., Skeletonema costatum-SKC, Tetraselmis sp.-TET, and Hymenomonas sp.-HYM) sampled at different phases of growth. Results showed that flux reduction and irreversible fouling were more severe during the decline phase as compared to the exponential phase, for all species. SKC and TET were responsible for substantial irreversible fouling but their impact was significantly lower than HYM. The development of a transparent gel layer surrounding the cell during the HYM growth and accumulating in water is certainly responsible for the more severe observed fouling. Chemical backwash with a standard chlorine solution did not recover any membrane permeability. For TET and HYM, the Hydraulically Irreversible Fouling Index (HIFI) was correlated to their biopolymer content but this correlation is specific for each species. Solution pre-filtration through a 1.2 μm membrane proved that cells and particulate algal organic matter (p-AOM) considerably contribute to fouling, especially for HYM for which the HIFI was reduced by a factor of 82.3. PMID:26874470

  2. Differential response to green algal species to solvents

    SciTech Connect

    Tadros, M.G.; Philips, J.; Patel, H.; Pandiripally, V. )

    1994-03-01

    Unicellular algae in aquatic ecosystems are subjected to a variety of pollutants from sources such as runoff from agricultural lands and industrial outfalls. Organic solvents are natural components of oil deposits and commonly find their way into surface waters as a result discharges from refineries, waste oil, disposal, and accidental spills. Organic solvents can make their way into the environment as industrial wastes. Because of their carcinogenic potential, contamination of soil and water by solvents is cause for serious concern. Relatively few reports have been published on the comparative toxicity of solvents toward test organisms, and these dealt primarily with fish and aquatic invertebrates. However, limited data of toxicity effects of solvents on algae have been published. Algae have been considered to be good indicators of bioactivity of industrial wastes. Unicellular algae vary in their response to a variety of toxicants. Little is known, however, about toxicity of solvents to freshwater unicellular green algae. The work reported here was done to examine the effect of selected solvents on unicellular green algae species to determine whether they differed in their responses to these chemicals. 14 refs., 1 fig.

  3. Differential effects of copper on three species of scleractinian corals and their algal symbionts (Symbiodinium spp.).

    PubMed

    Bielmyer, G K; Grosell, M; Bhagooli, R; Baker, A C; Langdon, C; Gillette, P; Capo, T R

    2010-04-15

    Land-based sources of pollution have been identified as significant stressors linked to the widespread declines of coral cover in coastal reef ecosystems over the last 30 years. Metal contaminants, although noted as a concern, have not been closely monitored in these sensitive ecosystems, nor have their potential impacts on coral-algal symbioses been characterized. In this study, three species of laboratory-reared scleractinian corals, Acropora cervicornis, Pocillopora damicornis, and Montastraea faveolata each containing different algal symbionts (Symbiodinium A3, C1 and D1a, respectively) were exposed to copper (ranging from 2 to 20microg/L) for 5 weeks. At the end of the exposure period, copper had accumulated in the endosymbiotic dinoflagellate ("zooxanthellae") and animal tissue of A. cervicornis and the animal tissue of M. faveolata; however, no copper accumulation was detected in the zooxanthellae or animal tissue of P. damicornis. The three coral species exhibited significantly different sensitivities to copper, with effects occurring in A. cervicornis and P. damicornis at copper concentrations as low as 4microg/L. Copper exposure affected zooxanthellae photosynthesis in A. cervicornis and P. damicornis, and carbonic anhydrase was significantly decreased in A. cervicornis and M. faveolata. Likewise, significant decreases in skeletal growth were observed in A. cervicornis and P. damicornis after copper exposure. Based on preliminary results, no changes in Symbiodinium communities were apparent in response to increasing copper concentration. These results indicate that the relationships between physiological/toxicological endpoints and copper accumulation between coral species differ, suggesting different mechanisms of toxicity and/or susceptibility. This may be driven, in part, by differences in the algal symbiont communities of the coral species in question. PMID:20089320

  4. Impacts of zooplankton composition and algal enrichment on the accumulation of mercury in an experimental freshwater food web.

    PubMed

    Pickhardt, Paul C; Folt, Carol L; Chen, Celia Y; Klaue, Bjoern; Blum, Joel D

    2005-03-01

    There is a well documented accumulation of mercury in fish to concentrations of concern for human consumption. Variation in fish Hg burden between lakes is often high and may result from differences in Hg transfer through lower levels of the food web where mercury is bioconcentrated to phytoplankton and transferred to herbivorous zooplankton. Prior research derived patterns of mercury accumulation in freshwater invertebrates from field collected animals. This study provides results from controlled mesocosm experiments comparing the effects of zooplankton composition, algal abundance, and the chemical speciation of mercury on the ability of zooplankton to accumulate mercury from phytoplankton and transfer that mercury to planktivores. Experiments were conducted in 550-L mesocosms across a gradient of algal densities manipulated by inorganic nutrient additions. Enriched, stable isotopes of organic (CH3(200HgCl)) and inorganic (201HgCl2) mercury were added to mesocosms and their concentrations measured in water, seston, and three common zooplankton species. After 2 weeks, monomethylmercury (MMHg) concentrations were two to three times lower in the two copepod species, Leptodiaptomus minutus and Mesocyclops edax than in the cladoceran, Daphnia mendotae. All three zooplankton species had higher MMHg concentrations in mesocosms with low versus high initial algal abundance. However, despite higher concentrations of inorganic mercury (HgI) in seston from low nutrient mesocosms, there were no significant differences in the HgI accumulated by zooplankton across nutrient treatments. Bioaccumulation factors for MMHg in the plankton were similar to those calculated for plankton in natural lakes and a four-compartment (aqueous, seston, macrozooplankton, and periphyton/sediments) mass balance model after 21 days accounted for approximately 18% of the CH3(200Hg) and approximately 33% of the 201Hg added. Results from our experiments corroborate results from field studies and

  5. c-AMP dependent protein kinase A inhibitory activity of six algal extracts from southeastern Australia and their fatty acid composition.

    PubMed

    Zivanovic, Ana; Skropeta, Danielle

    2012-07-01

    c-AMP dependent protein kinase (protein kinase A, PKA) is an important enzyme involved in the regulation of an increasing number of physiological processes including immune function, cardiovascular disease, memory disorders and cancer. The objective of this study was to evaluate the PKA inhibitory activity of a range of algal extracts, along with their fatty acid composition. Six algal species were investigated including two Chlorophyta (Codium dimorphum and Ulva lactuca), two Phaeophyta (Phyllospora comosa and Sargassum sp.) and two Rhodophyta (Prionitis linearis and Corallina vancouveriensis), with the order of PKA inhibitory activity of their extracts identified as follows: brown seaweeds > red seaweeds > green seaweeds with the brown alga Sargassum sp. exhibiting the highest PKA inhibitory activity (84% at 100 microg/mL). GC/MS analysis identified a total of 18 fatty acids in the six algal extracts accounting for 72-87% of each extract, with hexadecanoic acid and 9,12-octadecadienoic acid as the dominant components. The most active extract (Sargassum sp.) also contained the highest percentage of the saturated C14:0 fatty acid (12.8% of the total extract), which is a known to inhibit PKA. These results provide the first description of the PKA inhibitory activity of marine algae along with the first description of the fatty acid composition of these six algal species from South Eastern Australian waters. Importantly, this study reveals that abundant and readily available marine algae are a new and relatively unexplored source of PKA inhibitory compounds. PMID:22908583

  6. Identification of a new marine algal species Pyropia nitida sp. nov. (Bangiales: Rhodophyta) from Monterey, California.

    PubMed

    Harden, Leeanne K; Morales, Karina M; Hughey, Jeffery R

    2016-07-01

    An unidentified marine red algal species classified in Pyropia J. Agardh was discovered from Monterey, CA. Morphological, barcode, and complete mitochondrial genome analysis of the alga support its recognition as a new species, Pyropia nitida sp. nov. The species is a high-intertidal, winter annual that is lanceolate in shape, monostromatic, and dioecious. Based on CO1 sequences, P. nitida is closely allied with the P. nereocystis clade. The mitogenome of P. nitida is 35 313 bp in length and contains 53 genes, including two ribosomal RNAs, 24 transfer RNAs, four ribosomal proteins, two ymfs, four ORFs, and 17 genes involved in electron transport and oxidative phosphorylation. The results support the recognition of P. nitida as distinct from the morphologically similar P. lanceolata. PMID:26153737

  7. Preliminary evaluation of an in vivo fluorometer to quantify algal periphyton biomass and community composition

    USGS Publications Warehouse

    Harris, Theodore D.; Graham, Jennifer

    2015-01-01

    The bbe-Moldaenke BenthoTorch (BT) is an in vivo fluorometer designed to quantify algal biomass and community composition in benthic environments. The BT quantifies total algal biomass via chlorophyll a (Chl-a) concentration and may differentiate among cyanobacteria, green algae, and diatoms based on pigment fluorescence. To evaluate how BT measurements of periphytic algal biomass (as Chl-a) compared with an ethanol extraction laboratory analysis, we collected BT- and laboratory-measured Chl-a data from 6 stream sites in the Indian Creek basin, Johnson County, Kansas, during August and September 2012. BT-measured Chl-a concentrations were positively related to laboratory-measured concentrations (R2 = 0.47); sites with abundant filamentous algae had weaker relations (R2 = 0.27). Additionally, on a single sample date, we used the BT to determine periphyton biomass and community composition upstream and downstream from 2 wastewater treatment facilities (WWTF) that discharge into Indian Creek. We found that algal biomass increased immediately downstream from the WWTF discharge then slowly decreased as distance from the WWTF increased. Changes in periphyton community structure also occurred; however, there were discrepancies between BT- and laboratory-measured community composition data. Most notably, cyanobacteria were present at all sites based on BT measurements but were present at only one site based on laboratory-analyzed samples. Overall, we found that the BT compared reasonably well with laboratory methods for relative patterns in Chl-a but not as well with absolute Chl-aconcentrations. Future studies need to test the BT over a wider range of Chl-aconcentrations, in colored waters, and across various periphyton assemblages.

  8. Bioaccumulation of heavy metals by freshwater algal species of Bhavnagar, Gujarat, India.

    PubMed

    Jaiswar, Santial; Kazi, Mudassar Anisoddin; Mehta, Shailesh

    2015-11-01

    The present study investigated copper, cadmium, lead and zinc accumulation in algal species Oedogonium, Cladophora, Oscillatoria and Spirogyra from freshwater habitats of Bhavnagar, India. Eight different locations were periodically sampled during August 2009 to March 2011. The general trend of heavy metal concentrations in all the algal species in present study (except at few stations), were found to be in the following order: Zn > Cu > Pb > Cd. Highest accumulation of Cu was recorded in Oedogonium, while Cladophora showed highest accumulation of Pb signifying a good bioaccumulator. Oscillatoria and Oedogonium were highest Zn accumulating algae which showed significant difference between the means at P < 0.05. ANOVA was performed for comparing significance mean between the groups and within the group for heavy metals in water. The concentration of heavy metals in water was in the following order: Zn > Cu > Pb > Cd. The present study showed that Oedogonium, Cladophora, Oscillatoria and Spirogyra were excellent bioaccumulator and could be utilized as biomonitoring agents in water bodies receiving waste contaminated by metals. PMID:26688974

  9. Oxygen Metabolic Responses of Three Species of Large Benthic Foraminifers with Algal Symbionts to Temperature Stress

    PubMed Central

    Fujita, Kazuhiko; Okai, Takaaki; Hosono, Takashi

    2014-01-01

    Water temperature affects the physiology of large benthic foraminifers (LBFs) with algal symbionts dwelling in coral reef environments. However, the detailed physiological responses of LBF holobionts to temperature ranges occurring in their habitats are not known. We report net oxygen (O2) production and respiration rates of three LBF holobionts (Baculogypsina sphaerulata and Calcarina gaudichaudii hosting diatom symbionts, and Amphisorus kudakajimensis hosting dinoflagellate symbionts) measured in the laboratory at water temperatures ranging from 5°C to 45°C in 2.5°C or 5°C intervals and with light saturation levels of ∼500 µmol m−2 s−1. In addition, the recovery of net O2 production and respiration rates after exposure to temperature stress was assessed. The net O2 production and respiration rates of the three LBF holobionts peaked at ∼30°C, indicating their optimal temperature for a short exposure period. At extreme high temperatures (≥40°C), the net O2 production rates of all three LBF holobionts declined to less than zero and the respiration rates slightly decreased, indicating that photosynthesis of algal symbionts was inactivated. At extreme low temperatures (≤10°C for two calcarinid species and ≤5°C for A. kudakajimensis), the net O2 production and respiration rates were near zero, indicating a weakening of holobiont activity. After exposure to extreme high or low temperature, the net O2 production rates did not recover until the following day, whereas the respiration rates recovered rapidly, suggesting that a longer time (days) is required for recovery from damage to the photosystem by temperature stress compared to the respiration system. These results indicate that the oxygen metabolism of LBF holobionts can generally cope well with conditions that fluctuate diurnally and seasonally in their habitats. However, temporal heat and cold stresses with high light levels may induce severe damage to algal symbionts and also damage to host

  10. Algivore or Phototroph? Plakobranchus ocellatus (Gastropoda) Continuously Acquires Kleptoplasts and Nutrition from Multiple Algal Species in Nature

    PubMed Central

    Maeda, Taro; Hirose, Euichi; Chikaraishi, Yoshito; Kawato, Masaru; Takishita, Kiyotaka; Yoshida, Takao; Verbruggen, Heroen; Tanaka, Jiro; Shimamura, Shigeru; Takaki, Yoshihiro; Tsuchiya, Masashi; Iwai, Kenji; Maruyama, Tadashi

    2012-01-01

    The sea slug Plakobranchus ocellatus (Sacoglossa, Gastropoda) retains photosynthetically active chloroplasts from ingested algae (functional kleptoplasts) in the epithelial cells of its digestive gland for up to 10 months. While its feeding behavior has not been observed in natural habitats, two hypotheses have been proposed: 1) adult P. ocellatus uses kleptoplasts to obtain photosynthates and nutritionally behaves as a photoautotroph without replenishing the kleptoplasts; or 2) it behaves as a mixotroph (photoautotroph and herbivorous consumer) and replenishes kleptoplasts continually or periodically. To address the question of which hypothesis is more likely, we examined the source algae for kleptoplasts and temporal changes in kleptoplast composition and nutritional contribution. By characterizing the temporal diversity of P. ocellatus kleptoplasts using rbcL sequences, we found that P. ocellatus harvests kleptoplasts from at least 8 different siphonous green algal species, that kleptoplasts from more than one species are present in each individual sea slug, and that the kleptoplast composition differs temporally. These results suggest that wild P. ocellatus often feed on multiple species of siphonous algae from which they continually obtain fresh chloroplasts. By estimating the trophic position of wild and starved P. ocellatus using the stable nitrogen isotopic composition of amino acids, we showed that despite the abundance of kleptoplasts, their photosynthates do not contribute greatly to the nutrition of wild P. ocellatus, but that kleptoplast photosynthates form a significant source of nutrition for starved sea slugs. The herbivorous nature of wild P. ocellatus is consistent with insights from molecular analyses indicating that kleptoplasts are frequently replenished from ingested algae, leading to the conclusion that natural populations of P. ocellatus do not rely on photosynthesis but mainly on the digestion of ingested algae. PMID:22848693

  11. Delineation of six species of the primitive algal genus Glaucocystis based on in situ ultrastructural characteristics.

    PubMed

    Takahashi, Toshiyuki; Nishida, Tomoki; Tuji, Akihiro; Saito, Chieko; Matsuzaki, Ryo; Sato, Mayuko; Toyooka, Kiminori; Yasuda, Hidehiro; Nozaki, Hisayoshi

    2016-01-01

    The field of microbiology was established in the 17(th) century upon the discovery of microorganisms by Antonie van Leeuwenhoek using a single-lens microscope. Now, the detailed ultrastructures of microorganisms can be elucidated in situ using three-dimensional electron microscopy. Since the availability of electron microscopy, the taxonomy of microscopic organisms has entered a new era. Here, we established a new taxonomic system of the primitive algal genus Glaucocystis (Glaucophyta) using a new-generation electron microscopic methodology: ultra-high-voltage electron microscopy (UHVEM) and field-emission scanning electron microscopy (FE-SEM). Various globally distributed Glaucocystis strains were delineated into six species, based on differences in in situ ultrastructural features of the protoplast periphery under UHVEM tomography and in the mother cell wall by FE-SEM, as well as differences in the light microscopic characteristics and molecular phylogenetic results. The present work on Glaucocystis provides a model case of new-generation taxonomy. PMID:27383831

  12. Delineation of six species of the primitive algal genus Glaucocystis based on in situ ultrastructural characteristics

    PubMed Central

    Takahashi, Toshiyuki; Nishida, Tomoki; Tuji, Akihiro; Saito, Chieko; Matsuzaki, Ryo; Sato, Mayuko; Toyooka, Kiminori; Yasuda, Hidehiro; Nozaki, Hisayoshi

    2016-01-01

    The field of microbiology was established in the 17th century upon the discovery of microorganisms by Antonie van Leeuwenhoek using a single-lens microscope. Now, the detailed ultrastructures of microorganisms can be elucidated in situ using three-dimensional electron microscopy. Since the availability of electron microscopy, the taxonomy of microscopic organisms has entered a new era. Here, we established a new taxonomic system of the primitive algal genus Glaucocystis (Glaucophyta) using a new-generation electron microscopic methodology: ultra-high-voltage electron microscopy (UHVEM) and field-emission scanning electron microscopy (FE-SEM). Various globally distributed Glaucocystis strains were delineated into six species, based on differences in in situ ultrastructural features of the protoplast periphery under UHVEM tomography and in the mother cell wall by FE-SEM, as well as differences in the light microscopic characteristics and molecular phylogenetic results. The present work on Glaucocystis provides a model case of new-generation taxonomy. PMID:27383831

  13. Preparation and Characterization of Algal Polysaccharides/Magnetite Microparticles Composite Films

    NASA Astrophysics Data System (ADS)

    Diaz-Bleis, D.; Freile-Pelegrín, Y.; Vales-Pinzón, C.; Martínez-Torres, P.; Alvarado-Gil, J. J.

    2012-11-01

    Composites of magnetic particles in a polymeric matrix have received increasing interest due to their capacity to respond to external magnetic or electromagnetic fields. Algal polysaccharides such as agar are used extensively as gel-forming agents, thickeners, and stabilizers due to their low cost and high degree of biocompatibility and biodegradability. This study is focused on the preparation and characterization of algal polysaccharides-carbonyl iron composite films. The samples were analyzed using the photothermal radiometry (PTR) technique in the back-propagation emission configuration performing a modulation frequency scan. The amplitude and phase of the PTR experimental data were fitted simultaneously using a one-layer thermal-wave model considering homogeneous optical and thermal properties. The results indicate a systematic increase of the thermal diffusivity and optical absorption coefficient when the magnetic particle content increases. Scanning electron microscopy surface morphology of the agar/carbonyl iron composite indicates that a homogeneous distribution of particles can be obtained with the reported procedure and also provides evidence of agglomeration at high concentrations.

  14. Isolation and identification of bacteria associated with the surfaces of several algal species

    NASA Astrophysics Data System (ADS)

    Wang, Zifeng; Xiao, Tian; Pang, Shaojun; Liu, Min; Yue, Haidong

    2009-09-01

    We conducted this study to assess the diversity of bacteria associated with the surfaces of algae based on 16S rDNA sequence analyses. Twelve strains of bacteria were obtained from the surfaces of the following four species of algae: Gracilaria textorii, Ulva pertusa, Laminaria japonica, and Polysiphonia urceolata. The isolated strains of bacteria can be divided into two groups: Halomonas and Vibrio, in physiology, biochemical characteristics and 16S rDNA sequence analyses. The phylogenetic tree constructed based on 16S rDNA sequences of the isolates shows four obvious clusters, Halomonas venusta, Vibrio tasmaniensis, Vibrio lentus, and Vibrio splendidus. Isolates from the surface of P. urceolata are more abundant and diverse, of which strains P9 and P28 have a 16S rDNA sequence very similar (97.5%-99.8%) to that of V. splendidus. On the contrary, the isolates from the surfaces of G. textorii, U. pertusa and L. japonica are quite simple and distribute on different branches of the phylogenetic tree. In overall, the results of this study indicate that the genetic relationships among the isolates are quite close and display a certain level of host species specificity, and alga-associated bacteria species are algal species specific.

  15. Species identification of mixed algal bloom in the Northern Arabian Sea using remote sensing techniques.

    PubMed

    Dwivedi, R; Rafeeq, M; Smitha, B R; Padmakumar, K B; Thomas, Lathika Cicily; Sanjeevan, V N; Prakash, Prince; Raman, Mini

    2015-02-01

    Oceanic waters of the Northern Arabian Sea experience massive algal blooms during winter-spring (mid Feb-end Mar), which prevail for at least for 3 months covering the entire northern half of the basin from east to west. Ship cruises were conducted during winter-spring of 2001-2012 covering different stages of the bloom to study the biogeochemistry of the region. Phytoplankton analysis indicated the presence of green tides of dinoflagellate, Noctiluca scintillans (=N. miliaris), in the oceanic waters. Our observations indicated that diatoms are coupled and often co-exist with N. scintillans, making it a mixed-species ecosystem. In this paper, we describe an approach for detection of bloom-forming algae N. scintillans and its discrimination from diatoms using Moderate Resolution Imaging Spectroradiometer (MODIS)-Aqua data in a mixed-species environment. In situ remote sensing reflectance spectra were generated using Satlantic™ hyperspectral radiometer for the bloom and non-bloom waters. Spectral shapes of the reflectance spectra for different water types were distinct, and the same were used for species identification. Scatter of points representing different phytoplankton classes on a derivative plot revealed four diverse clusters, viz. N. scintillans, diatoms, non-bloom oceanic, and non-bloom coastal waters. The criteria developed for species discrimination were implemented on MODIS data and validated using inputs from a recent ship cruise conducted in March 2013. PMID:25638059

  16. The impact of atmospheric deposition of cadmium on dominant algal species in the East China Sea

    NASA Astrophysics Data System (ADS)

    Quan, Qiwei; Chen, Ying; Ma, Qingwei; Wang, Fujiang; Meng, Xi; Wang, Bo

    2016-04-01

    Cadmium (Cd) mainly derived from anthropogenic emissions can be transported through atmospheric pathway to marine ecosystem, affecting the phytoplankton community and primary productivity. In this study, we identified the toxicity threshold of Cd for phytoplankton under seawater conditions of the coastal East China Sea (ECS) through both laboratory and in situ mesocosm incubation experiments. The mesocosm experiment showed that Cd in low concentration (0.003 μg per μg chl a) was conducive to the growth of natural community and increased chl a productivity. In high concentration (0.03 μg per μg chl a) Cd acted as an inhibiting factor which decreased the total chl a productivity. The diatom community was found to be more sensitive to Cd toxicity than dinoflagellate, as the low concentration Cd showed toxicity to diatom but enhanced dinoflagellate growth. We noticed that the soluble Cd estimated from atmosphere deposition to the coastal ECS was below the toxicity threshold and the Cd deposition might promote phytoplankton growth in this region. In our laboratory experiments, adding Cd, similar to aerosol deposition, stimulated the growth of both dominant algal species Prorocentrum donghaiense Lu (dinoflagellate) and Skeletonema costatum (diatom). Adding Cd on a higher level inhibited the growth of both the species, but Skeletonema costatum seemed obviously more sensitive to toxicity. This indicates the potential impact of atmospheric deposition Cd on phytoplankton community succession in the ECS.

  17. Molecular detection and species identification of Alexandrium (Dinophyceae) causing harmful algal blooms along the Chilean coastline

    PubMed Central

    Jedlicki, Ana; Fernández, Gonzalo; Astorga, Marcela; Oyarzún, Pablo; Toro, Jorge E.; Navarro, Jorge M.; Martínez, Víctor

    2012-01-01

    Background and aims On the basis of morphological evidence, the species involved in South American Pacific coast harmful algal blooms (HABs) has been traditionally recognized as Alexandrium catenella (Dinophyceae). However, these observations have not been confirmed using evidence based on genomic sequence variability. Our principal objective was to accurately determine the species of Alexandrium involved in local HABs in order to implement a real-time polymerase chain reaction (PCR) assay for its rapid and easy detection on filter-feeding shellfish, such as mussels. Methodology For species-specific determination, the intergenic spacer 1 (ITS1), 5.8S subunit, ITS2 and the hypervariable genomic regions D1–D5 of the large ribosomal subunit of local strains were sequenced and compared with two data sets of other Alexandrium sequences. Species-specific primers were used to amplify signature sequences within the genomic DNA of the studied species by conventional and real-time PCR. Principal results Phylogenetic analysis determined that the Chilean strain falls into Group I of the tamarensis complex. Our results support the allocation of the Chilean Alexandrium species as a toxic Alexandrium tamarense rather than A. catenella, as currently defined. Once local species were determined to belong to Group I of the tamarensis complex, a highly sensitive and accurate real-time PCR procedure was developed to detect dinoflagellate presence in Mytilus spp. (Bivalvia) samples after being fed (challenged) in vitro with the Chilean Alexandrium strain. The results show that real-time PCR is useful to detect Alexandrium intake in filter-feeding molluscs. Conclusions It has been shown that the classification of local Alexandrium using morphological evidence is not very accurate. Molecular methods enabled the HAB dinoflagellate species of the Chilean coast to be assigned as A. tamarense rather than A. catenella. Real-time PCR analysis based on A. tamarense primers allowed the

  18. Algal and fungal diversity in Antarctic lichens.

    PubMed

    Park, Chae Haeng; Kim, Kyung Mo; Elvebakk, Arve; Kim, Ok-Sun; Jeong, Gajin; Hong, Soon Gyu

    2015-01-01

    The composition of lichen ecosystems except mycobiont and photobiont has not been evaluated intensively. In addition, recent studies to identify algal genotypes have raised questions about the specific relationship between mycobiont and photobiont. In the current study, we analyzed algal and fungal community structures in lichen species from King George Island, Antarctica, by pyrosequencing of eukaryotic large subunit (LSU) and algal internal transcribed spacer (ITS) domains of the nuclear rRNA gene. The sequencing results of LSU and ITS regions indicated that each lichen thallus contained diverse algal species. The major algal operational taxonomic unit (OTU) defined at a 99% similarity cutoff of LSU sequences accounted for 78.7-100% of the total algal community in each sample. In several cases, the major OTUs defined by LSU sequences were represented by two closely related OTUs defined by 98% sequence similarity of ITS domain. The results of LSU sequences indicated that lichen-associated fungi belonged to the Arthoniomycetes, Eurotiomycetes, Lecanoromycetes, Leotiomycetes, and Sordariomycetes of the Ascomycota, and Tremellomycetes and Cystobasidiomycetes of the Basidiomycota. The composition of major photobiont species and lichen-associated fungal community were mostly related to the mycobiont species. The contribution of growth forms or substrates on composition of photobiont and lichen-associated fungi was not evident. PMID:25105247

  19. Laboratory evaluation of six algal species for larval nutritional suitability of the pestiferous midge Glyptotendipes paripes (Diptera: Chironomidae).

    PubMed

    Frouz, Jan; Ali, Arshad; Lobinske, Richard J

    2004-12-01

    Glyptotendipes paripes Edwards midge larval growth, development, survival, emerging adult size, and food digestibility when provided with six species of algae as food were studied in the laboratory. For the study, eggs from G. paripes adults maintained in the laboratory were reared to the adult stage at 30 degrees C for 60 d on pure culture of each algal species at densities of 0.4, 0.1, and 0.02 mg of algae (fresh weight) per milliliter, as a sole food source. All larvae reared on Microcystis sp., Botryoccocus braunii, and Scenedesmus quadricauda died before completing development. The only larvae to complete development to adult were those reared on 0.4 mg/ml Lyngbia cf. aeruginosa (44.0 d), Anabaena flos-aquae (29.7 d), and Chlorella keslerii (44.8 d). No significant differences in body size of the adults achieving complete development on the three algal species were found. Algal digestion, measured by comparing amounts of live and dead algal cells in remains of cultures used for feeding and in larval excrement, revealed that >95% of all L. cf. aeruginosa, A. flos-aquae, and Microcystis sp. cells were digested; for C. keslerii, 13% of cells were digested, whereas little or no digestion of B. braunii and S. quadricauda was observed. To evaluate the effects of algal species on larval growth, laboratory-reared (on artificial food) late third/early fourth instars of G. paripes were fed individual algal species, and 10 d later, body mass changes were recorded and compared with nonfed larvae. Body mass of larvae reared on L. cf. aeruginosa and A. flos-aquae significantly increased, whereas those provided Microcystis sp. and the nonfed larvae showed significant body mass reductions. Overall, B. braunii and S. quadricauda were not suitable as larval food, probably due to their low digestibility, and Microcystis sp. because of its toxicity. This study identifies some algae that do and others that do not support G. paripes larval growth. The information is useful in

  20. Measurement and feature analysis of absorption spectra of four algal species

    NASA Astrophysics Data System (ADS)

    Zhu, Jianhua; Zhou, Hongli; Han, Bing; Li, Tongji

    2016-04-01

    Two methods for particulate pigments (i.e., quantitative filter technique, QFT, and in vivo measurement, InVivo, respectively) and two methods for dissolved pigments (i.e., Acetone Extracts, AceEx, and high-performance liquid chromatography, HPLC, respectively) were used to obtain the optical absorption coefficient spectra for cultures of four typical algal species. Through normalization and analysis of the spectra, it is shown that (1) the four methods are able to measure optical absorption spectra of particulate and/or dissolved pigments; (2) that the optical absorption spectra of particulate and dissolved pigments were consistent in terms of the peak position in the blue wavelength, and the difference of the peak position in the near infrared wavelength was ~10 nm between each other; and (3) that the leveling effect of the absorption spectra of particulate pigments was significant. These four methods can all effectively measure the absorption coefficients of phytoplankton pigments, while each one has its unique advantages in different applications. Therefore, appropriate method should be carefully selected for various application due to their intrinsic difference.

  1. Exploration of the antioxidant system and photosynthetic system of a marine algicidal Bacillus and its effect on four harmful algal bloom species.

    PubMed

    Hou, Shaoling; Shu, Wanjiao; Tan, Shuo; Zhao, Ling; Yin, Pinghe

    2016-01-01

    A novel marine bacterium, strain B1, initially showed 96.4% algicidal activity against Phaeocystis globosa. Under this situation, 3 other harmful algal species (Skeletonema costatum, Heterosigma akashiwo, and Prorocentrum donghaiense) were chosen to study the algicidal effects of strain B1, and the algicidal activities were 91.4%, 90.7%, and 90.6%, respectively. To explore the algicidal mechanism of strain B1 on these 4 harmful algal species, the characteristics of the antioxidant system and photosynthetic system were studied. Sensitivity to strain B1 supernatant, enzyme activity, and gene expression varied with algal species, while the algicidal patterns were similar. Strain B1 supernatant increased malondialdehyde contents; decreased chlorophyll a contents; changed total antioxidant and superoxide dismutase activity; and restrained psbA, psbD, and rbcL genes expression, which eventually resulted in the algal cells death. The algicidal procedure was observed using field emission scanning electron microscopy, which indicated that algal cells were lysed and cellular substances were released. These findings suggested that the antioxidant and photosynthetic system of these 4 algal species was destroyed under strain B1 supernatant stress. This is the first report to explore and compare the mechanism of a marine Bacillus against harmful algal bloom species of covered 4 phyla. PMID:26634608

  2. Crustose coralline algal species host distinct bacterial assemblages on their surfaces.

    PubMed

    Sneed, Jennifer M; Ritson-Williams, Raphael; Paul, Valerie J

    2015-11-01

    Crustose coralline algae (CCA) are important components of many marine ecosystems. They aid in reef accretion and stabilization, create habitat for other organisms, contribute to carbon sequestration and are important settlement substrata for a number of marine invertebrates. Despite their ecological importance, little is known about the bacterial communities associated with CCA or whether differences in bacterial assemblages may have ecological implications. This study examined the bacterial communities on four different species of CCA collected in Belize using bacterial tag-encoded FLX amplicon pyrosequencing of the V1-V3 region of the 16S rDNA. CCA were dominated by Alphaproteobacteria, Gammaproteobacteria and Actinomycetes. At the operational taxonomic unit (OTU) level, each CCA species had a unique bacterial community that was significantly different from all other CCA species. Hydrolithon boergesenii and Titanoderma prototypum, CCA species that facilitate larval settlement in multiple corals, had higher abundances of OTUs related to bacteria that inhibit the growth and/or biofilm formation of coral pathogens. Fewer coral larvae settle on the surfaces of Paragoniolithon solubile and Porolithon pachydermum. These CCA species had higher abundances of OTUs related to known coral pathogens and cyanobacteria. Coral larvae may be able to use the observed differences in bacterial community composition on CCA species to assess the suitability of these substrata for settlement and selectively settle on CCA species that contain beneficial bacteria. PMID:25918832

  3. Application of LDH-release assay to cellular-level evaluation of the toxic potential of harmful algal species.

    PubMed

    Zou, Yanan; Kim, Daekyung; Yagi, Motoaki; Yamasaki, Yasuhiro; Kurita, Jun; Iida, Takaji; Matsuyama, Yukihiko; Yamaguchi, Kenichi; Oda, Tatsuya

    2013-01-01

    Lactate dehydrogenase (LDH)-release assay was applied to estimate the toxic potential of harmful algal species at the cellular level. African green monkey kidney (Vero), yellowtail fin epithelia (MJF), and rainbow trout gill (RTgill-W1) cells were used as target cells. A live cell suspension of Karenia mikimotoi (SUO-1) induced the release of LDH from these cell lines, while the activity of another strain, FUK, was much lower. The cell-free culture supernatants and ruptured cell suspensions of both strains of K. mikimotoi were less effective on LDH-release assay. Exposure experiments against abalone and shrimp revealed that SUO-1 showed much stronger lethal effects on these organisms than FUK. Among six phytoplankton species, three species known to be harmful algal species induced the release of LDH to different extents depending on the cell line, whereas the other three species, known to be non-toxic, showed no effects on any cell lines. These results suggest that LDH-release assay is a useful micro-plate assay for estimation of the toxic potential of harmful phytoplankton. PMID:23391929

  4. The death mechanism of the harmful algal bloom species Alexandrium tamarense induced by algicidal bacterium Deinococcus sp. Y35

    PubMed Central

    Li, Yi; Zhu, Hong; Lei, Xueqian; Zhang, Huajun; Cai, Guanjing; Chen, Zhangran; Fu, Lijun; Xu, Hong; Zheng, Tianling

    2015-01-01

    Harmful algal blooms (HABs) cause a variety of deleterious effects on aquatic ecosystems, especially the toxic dinoflagellate Alexandrium tamarense, which poses a serious threat to marine economic and human health based on releasing paralytic shellfish poison into the environment. The algicidal bacterium Deinococcus sp. Y35 which can induce growth inhibition on A. tamarense was used to investigate the functional mechanism. The growth status, reactive oxygen species (ROS) content, photosynthetic system and the nuclear system of algal cells were determined under algicidal activity. A culture of strain Y35 not only induced overproduction of ROS in algal cells within only 0.5 h of treatment, also decrease the total protein content as well as the response of the antioxidant enzyme. Meanwhile, lipid peroxidation was induced and cell membrane integrity was lost. Photosynthetic pigments including chlorophyll a and carotenoid decreased along with the photosynthetic efficiency being significantly inhibited. At the same time, photosynthesis-related gene expression showed down-regulation. More than, the destruction of cell nuclear structure and inhibition of proliferating cell nuclear antigen (PCNA) related gene expression were confirmed. The potential functional mechanism of the algicidal bacterium on A. tamarense was investigated and provided a novel viewpoint which could be used in HABs control. PMID:26441921

  5. The quantitative real-time PCR applications in the monitoring of marine harmful algal bloom (HAB) species.

    PubMed

    Penna, Antonella; Antonella, Penna; Galluzzi, Luca; Luca, Galluzzi

    2013-10-01

    In the last decade, various molecular methods (e.g., fluorescent hybridization assay, sandwich hybridization assay, automatized biosensor detection, real-time PCR assay) have been developed and implemented for accurate and specific identification and estimation of marine toxic microalgal species. This review focuses on the recent quantitative real-time PCR (qrt-PCR) technology developed for the control and monitoring of the most important taxonomic phytoplankton groups producing biotoxins with relevant negative impact on human health, the marine environment, and related economic activities. The high specificity and sensitivity of the qrt-PCR methods determined by the adequate choice of the genomic target gene, nucleic acid purification protocol, quantification through the standard curve, and type of chemical detection method make them highly efficient and therefore applicable to harmful algal bloom phenomena. Recent development of qrt-PCR-based assays using the target gene of toxins, such as saxitoxin compounds, has allowed more precise quantification of toxigenic species (i.e., Alexandrium catenella) abundance. These studies focus only on toxin-producing species in the marine environment. Therefore, qrt-PCR technology seems to offer the advantages of understanding the ecology of harmful algal bloom species and facilitating the management of their outbreaks. PMID:23247526

  6. Grazing preferences of marine isopods and amphipods on three prominent algal species of the Baltic Sea [rapid communication

    NASA Astrophysics Data System (ADS)

    Goecker, Margene E.; Kåll, Sara E.

    2003-12-01

    Preference tests were performed over a two-week period in September 2001 in which isopods ( Idotea baltica) and amphipods ( Gammarus oceanicus) were offered choices of three common species of algae from the Baltic Sea: Enteromorpha intestinalis, Cladophora spp., and Fucus vesiculosus. After a 48-hour starvation period, 20 individuals of each grazer species were placed in aquaria containing approximately 1.0 g of each algal species. Fifteen trials for each grazer species were run for 20 hours. We found that G. oceanicus ate significantly more Cladophora spp. and E. intestinalis than F. vesiculosus (p<0.001), with a preference order of: Cladophora spp.> E. intestinalis> F. vesiculosus. Similarly, I. baltica ate significantly more of both the filamentous green algae than F. vesiculosus (p<0.001), with a preference order of: E. intestinalis> Cladophora spp.> F. vesiculosus. Given the preference of isopods and amphipods for filamentous green algae, we might expect these algae to be maintained at low biomass levels. However, this is clearly not the case in the Baltic Sea. Nutrient enrichment (bottom-up effects) is the accepted dominant reason for the non-controlling impact of algal grazers, but other reasons may include cascading trophic effects resulting from the removal of large piscivorous fish (top-down effects).

  7. Algal and Invertebrate Community Composition along Agricultural Gradients: A Comparative Study from Two Regions of the Eastern United States

    USGS Publications Warehouse

    Calhoun, Daniel L.; Gregory, M. Brian; Weyers, Holly S.

    2008-01-01

    Benthic algal and invertebrate communities in two Coastal Plain regions of the Eastern United States?the Delmarva Peninsula (27 sites) and Georgia Upper Coastal Plain (29 sites)?were assessed to determine if aspects of agricultural land use and nutrient conditions (dissolved and whole-water nitrogen and phosphorus) could be linked to biological community compositions. Extensive effort was made to compile land-use data describing the basin and riparian conditions at multiple scales to determine if scale played a role in these relations. Large differences in nutrient condition were found between the two study areas, wherein on average, the Delmarva sites had three times the total phosphorus and total nitrogen as did the sites in the Georgia Upper Coastal Plain. A statistical approach was undertaken that included multivariate correlations between Bray-Curtis similarity matrices of the biological communities and Euclidean similarity matrices of instream nutrients and land-use categories. Invertebrate assemblage composition was most associated with land use near the sampled reach, and algal diatom assemblage composition was most associated with land use farther from the streams and into the watersheds. Link tree analyses were conducted to isolate portions of nonmetric multidimensional scaling ordinations of community compositions that could be explained by break points in abiotic datasets. Invertebrate communities were better defined by factors such as agricultural land use near streams and geographic position. Algal communities were better defined by agricultural land use at the basin scale and instream nutrient chemistry. Algal autecological indices were more correlated with gradients of nutrient condition than were typically employed invertebrate metrics and may hold more promise in indicating nutrient impairment in these regions. Nutrient conditions in the respective study areas are compared to draft nutrient criteria established by the U.S. Environmental Protection

  8. Spatial variability, structure and composition of crustose algal communities in Diadema africanum barrens

    NASA Astrophysics Data System (ADS)

    Sangil, Carlos; Sansón, Marta; Díaz-Villa, Tania; Hernández, José Carlos; Clemente, Sabrina; Afonso-Carrillo, Julio

    2014-12-01

    Crustose algal communities were studied in Diadema africanum urchin barrens around Tenerife (Canary Islands, NE Atlantic). A hierarchical nested sampling design was used to study patterns of community variability at different spatial scales (sectors, three sides of the island; sites within each sector, 5-10 km apart; stations within each site, 50-100 m apart). Although noncrustose species contributed the most to community richness, cover was dominated by crustose forms, like the coralline algae Hydrolithon farinosum, H. samoënse, H. onkodes, Neogoniolithon orotavicum and N. hirtum, and the phaeophycean Pseudolithoderma adriaticum. The structure of these communities showed high spatial variability, and we found differences in the structure of urchin barrens when compared across different spatial scales. Multivariate analysis showed that variability in community structure was related to the five environmental variables studied (wave exposure, urchin density, substrate roughness, productivity and depth). Wave exposure was the variable that contributed most to community variability, followed by urchin density and substrate roughness. Productivity and depth had limited influence. The effects of these variables differed depending on the spatial scale; wave exposure and productivity were the main variables influencing community changes at the largest scale (between different sectors of the island), while D. africanum density, roughness and depth were the most influential at medium and small scales.

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

    USGS Publications Warehouse

    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

  10. Molecular and Ecological Evidence for Species Specificity and Coevolution in a Group of Marine Algal-Bacterial Symbioses

    PubMed Central

    Ashen, Jon B.; Goff, Lynda J.

    2000-01-01

    The phylogenetic relationships of bacterial symbionts from three gall-bearing species in the marine red algal genus Prionitis (Rhodophyta) were inferred from 16S rDNA sequence analysis and compared to host phylogeny also inferred from sequence comparisons (nuclear ribosomal internal-transcribed-spacer region). Gall formation has been described previously on two species of Prionitis, P. lanceolata (from central California) and P. decipiens (from Peru). This investigation reports gall formation on a third related host, Prionitis filiformis. Phylogenetic analyses based on sequence comparisons place the bacteria as a single lineage within the Roseobacter grouping of the α subclass of the division Proteobacteria (99.4 to 98.25% sequence identity among phylotypes). Comparison of symbiont and host molecular phylogenies confirms the presence of three gall-bearing algal lineages and is consistent with the hypothesis that these red seaweeds and their bacterial symbionts are coevolving. The species specificity of these associations was investigated in nature by whole-cell hybridization of gall bacteria and in the laboratory by using cross-inoculation trials. Whole-cell in situ hybridization confirmed that a single bacterial symbiont phylotype is present in galls on each host. In laboratory trials, bacterial symbionts were incapable of inducing galls on alternate hosts (including two non-gall-bearing species). Symbiont-host specificity in Prionitis gall formation indicates an effective ecological separation between these closely related symbiont phylotypes and provides an example of a biological context in which to consider the organismic significance of 16S rDNA sequence variation. PMID:10877801

  11. A marine algicidal Thalassospira and its active substance against the harmful algal bloom species Karenia mikimotoi.

    PubMed

    Lu, Xiuhua; Zhou, Bin; Xu, Lili; Liu, Lin; Wang, Gangyuan; Liu, Xiaodong; Tang, Xuexi

    2016-06-01

    The aim of the present study was to obtain a marine bacterium active against Karenia mikimotoi from the East China Sea and to characterize its extracellular algicidal substances. Using preparative high-performance liquid chromatography (prep-HPLC) and electrospray ionization/quadrupole-time of flight mass spectrometer coupled with a high-performance liquid chromatography (LC/MS-Q-TOF) system, we purified the alga-lysing substance produced by strain ZR-2 and determined its molecular structure. Based on morphology and l6S ribosomal DNA (rDNA) sequence analysis, the ZR-2 strain was highly homologous to Thalassospira species. Algicidal activity against K. mikimotoi was detected in the cell-free filtrate but not in bacterial cells. The alga-lysing substance produced by ZR-2 was ethanol-soluble and thermostable, with a retention time of 6.3 min and a measured elemental composition of C7H5O2 ([M-H](-) ion at m/z 121.0295). The alga-lysing substance produced by ZR-2 was determined to be benzoic acid. Compared with the negative control, both purified ZR-2 bacteria-free filtrate and standard benzoic acid promoted K. mikimotoi cell disruption and induced K. mikimotoi cell content leakage. Our study is the first to report benzoic acid activity against K. mikimotoi as well as production of benzoic acid by a Thalassospira species. PMID:26846742

  12. A marine algicidal actinomycete and its active substance against the harmful algal bloom species Phaeocystis globosa.

    PubMed

    Zheng, Xiaowei; Zhang, Bangzhou; Zhang, Jinlong; Huang, Liping; Lin, Jing; Li, Xinyi; Zhou, Yanyan; Wang, Hui; Yang, Xiaoru; Su, Jianqiang; Tian, Yun; Zheng, Tianling

    2013-10-01

    A strain O4-6, which had pronounced algicidal effects to the harmful algal bloom causing alga Phaeocystis globosa, was isolated from mangrove sediments in the Yunxiao Mangrove National Nature Reserve, Fujian, China. Based on the 16S rRNA gene sequence and morphological characteristics, the isolate was found to be phylogenetically related to the genus Streptomyces and identified as Streptomyces malaysiensis O4-6. Heat stability, pH tolerance, molecular weight range and aqueous solubility were tested to characterize the algicidal compound secreted from O4-6. Results showed that the algicidal activity of this compound was not heat stable and not affected by pH changes. Residue extracted from the supernatant of O4-6 fermentation broth by ethyl acetate, was purified by Sephadex LH-20 column and silica gel column chromatography before further structure determination. Chemical structure of the responsible compound, named NIG355, was illustrated based on quadrupole time-of-flight mass spectrometry (Q-TOF-MS) and nuclear magnetic resonance (NMR) spectra. And this compound showed a stronger algicidal activity compared with other reported algicides. Furthermore, this article represents the first report of an algicide against P. globosa, and the compound may be potentially used as a bio-agent for controlling harmful algal blooms. PMID:23224407

  13. Algal Bioremediation of Waste Waters from Land-Based Aquaculture Using Ulva: Selecting Target Species and Strains

    PubMed Central

    Lawton, Rebecca J.; Mata, Leonardo; de Nys, Rocky; Paul, Nicholas A.

    2013-01-01

    The optimised reduction of dissolved nutrient loads in aquaculture effluents through bioremediation requires selection of appropriate algal species and strains. The objective of the current study was to identify target species and strains from the macroalgal genus Ulva for bioremediation of land-based aquaculture facilities in Eastern Australia. We surveyed land-based aquaculture facilities and natural coastal environments across three geographic locations in Eastern Australia to determine which species of Ulva occur naturally in this region and conducted growth trials at three temperature treatments on a subset of samples from each location to determine whether local strains had superior performance under local environmental conditions. DNA barcoding using the markers ITS and tufA identified six species of Ulva, with U. ohnoi being the most common blade species and U. sp. 3 the most common filamentous species. Both species occurred at multiple land-based aquaculture facilities in Townsville and Brisbane and multiple strains of each species grew well in culture. Specific growth rates of U. ohnoi and U. sp. 3 were high (over 9% and 15% day−1 respectively) across temperature treatments. Within species, strains of U. ohnoi had higher growth in temperatures corresponding to local conditions, suggesting that strains may be locally adapted. However, across all temperature treatments Townsville strains had the highest growth rates (11.2–20.4% day−1) and Sydney strains had the lowest growth rates (2.5–8.3% day−1). We also found significant differences in growth between strains of U. ohnoi collected from the same geographic location, highlighting the potential to isolate and cultivate fast growing strains. In contrast, there was no clearly identifiable competitive strain of filamentous Ulva, with multiple species and strains having variable performance. The fast growth rates and broad geographical distribution of U. ohnoi make this an ideal species to target for

  14. Producing docosahexaenoic acid (DHA)-rich algae from biodiesel-derived crude glycerol: effects of impurities on DHA production and algal biomass composition.

    PubMed

    Pyle, Denver J; Garcia, Rafael A; Wen, Zhiyou

    2008-06-11

    Crude glycerol is the primary byproduct of the biodiesel industry. Producing docosahexaenoic acid (DHA, 22:6 n-3) through fermentation of the alga Schizochytrium limacinum on crude glycerol provides a unique opportunity to utilize a large quantity of this byproduct. The objective of this work is to investigate the effects of impurities contained in the crude glycerol on DHA production and algal biomass composition. Crude glycerol streams were obtained from different biodiesel refineries. All of the glycerol samples contained methanol, soaps, and various elements including calcium, phosphorus, potassium, silicon, sodium, and zinc. Both methanol and soap were found to negatively influence algal DHA production; these two impurities can be removed from culture medium by evaporation through autoclaving (for methanol) and by precipitation through pH adjustment (for soap). The glycerol-derived algal biomass contained 45-50% lipid, 14-20% protein, and 25% carbohydrate, with 8-13% ash content. Palmitic acid (C16:0) and DHA were the two major fatty acids in the algal lipid. The algal biomass was rich in lysine and cysteine, relative to many common feedstuffs. Elemental analysis by inductively coupled plasma showed that boron, calcium, copper, iron, magnesium, phosphorus, potassium, silicon, sodium, and sulfur were present in the biomass, whereas no heavy metals (such as mercury) were detected in the algal biomass. Overall, the results show that crude glycerol was a suitable carbon source for algal fermentation. The crude glycerol-derived algal biomass had a high level of DHA and a nutritional profile similar to that of commercial algal biomass, suggesting a great potential for using crude glycerol-derived algae in omega-3-fortified food or feed. PMID:18465872

  15. Impact of several harmful algal bloom (HAB) causing species, on life history characteristics of rotifer Brachionus plicatilis Müller

    NASA Astrophysics Data System (ADS)

    Lin, Jianing; Yan, Tian; Zhang, Qingchun; Zhou, Mingjiang

    2016-07-01

    In recent years, harmful algal blooms (HABs) have occurred frequently along the coast of China, and have been exhibiting succession from diatom- to dinoflagellate-dominated blooms. To examine the effects of different diatom and dinoflagellate HABs, the life history parameters of rotifers ( Brachionus plicatilis Müller) were measured after exposure to different concentrations of HAB species. The HAB species examined included a diatom ( Skeletonema costatum) and four dinoflagellates ( Prorocentrum donghaiense, Alexandrium catenella, Prorocentrum lima and Karlodinium veneficum). Compared with the control treatment (CT), the diatom S. costatum showed no adverse impacts on rotifers. Exposure to dinoflagellates at densities equivalent to those measured in the field resulted in a reduction in all the life history parameters measured. This included a reduction in: lifetime egg production (CT: 20.34 eggs/ind.) reduced to 10.11, 3.22, 4.17, 7.16 eggs/ind., life span (CT: 394.53 h) reduced to 261.11, 162.90, 203.67, 196 h, net reproductive rate (CT: 19.51/ind.) reduced to 3.01, 1.26, 3.53, 5.96/ind., finite rate of increase (CT: 1.47/d) reduced to 1.16, 1.03, 1.33, 1.38/d, and intrinsic rate of population increase (CT: 0.39/d) reduced to 0.15, 0.03, 0.28, 0.32/d, for the dinoflagellates P. donghaiense, A. catenella, P. lima and K. veneficum, respectively. The results showed that the diatom S. costatum had no detrimental consequences on the reproduction and growth of B. plicatilis, however, the four dinoflagellates tested did show adverse effects. This suggests that dinoflagellate HABs may suppress microzooplankton, resulting in an increase in algal numbers.

  16. Impact of several harmful algal bloom (HAB) causing species, on life history characteristics of rotifer Brachionus plicatilis Müller

    NASA Astrophysics Data System (ADS)

    Lin, Jianing; Yan, Tian; Zhang, Qingchun; Zhou, Mingjiang

    2015-12-01

    In recent years, harmful algal blooms (HABs) have occurred frequently along the coast of China, and have been exhibiting succession from diatom- to dinoflagellate-dominated blooms. To examine the effects of different diatom and dinoflagellate HABs, the life history parameters of rotifers (Brachionus plicatilis Müller) were measured after exposure to different concentrations of HAB species. The HAB species examined included a diatom (Skeletonema costatum) and four dinoflagellates (Prorocentrum donghaiense, Alexandrium catenella, Prorocentrum lima and Karlodinium veneficum). Compared with the control treatment (CT), the diatom S. costatum showed no adverse impacts on rotifers. Exposure to dinoflagellates at densities equivalent to those measured in the field resulted in a reduction in all the life history parameters measured. This included a reduction in: lifetime egg production (CT: 20.34 eggs/ind.) reduced to 10.11, 3.22, 4.17, 7.16 eggs/ind., life span (CT: 394.53 h) reduced to 261.11, 162.90, 203.67, 196 h, net reproductive rate (CT: 19.51/ind.) reduced to 3.01, 1.26, 3.53, 5.96/ind., finite rate of increase (CT: 1.47/d) reduced to 1.16, 1.03, 1.33, 1.38/d, and intrinsic rate of population increase (CT: 0.39/d) reduced to 0.15, 0.03, 0.28, 0.32/d, for the dinoflagellates P. donghaiense, A. catenella, P. lima and K. veneficum, respectively. The results showed that the diatom S. costatum had no detrimental consequences on the reproduction and growth of B. plicatilis, however, the four dinoflagellates tested did show adverse effects. This suggests that dinoflagellate HABs may suppress microzooplankton, resulting in an increase in algal numbers.

  17. Accelerating Commercialization of Algal Biofuels Through Partnerships (Brochure)

    SciTech Connect

    Not Available

    2011-10-01

    This brochure describes National Renewable Energy Laboratory's (NREL's) algal biofuels research capabilities and partnership opportunities. NREL is accelerating algal biofuels commercialization through: (1) Advances in applied biology; (2) Algal strain development; (3) Development of fuel conversion pathways; (4) Techno-economic analysis; and (5) Development of high-throughput lipid analysis methodologies. NREL scientists and engineers are addressing challenges across the algal biofuels value chain, including algal biology, cultivation, harvesting and extraction, and fuel conversion. Through partnerships, NREL can share knowledge and capabilities in the following areas: (1) Algal Biology - A fundamental understanding of algal biology is key to developing cost-effective algal biofuels processes. NREL scientists are experts in the isolation and characterization of microalgal species. They are identifying genes and pathways involved in biofuel production. In addition, they have developed a high-throughput, non-destructive technique for assessing lipid production in microalgae. (2) Cultivation - NREL researchers study algal growth capabilities and perform compositional analysis of algal biomass. Laboratory-scale photobioreactors and 1-m2 open raceway ponds in an on-site greenhouse allow for year-round cultivation of algae under a variety of conditions. A bioenergy-focused algal strain collection is being established at NREL, and our laboratory houses a cryopreservation system for long-term maintenance of algal cultures and preservation of intellectual property. (3) Harvesting and Extraction - NREL is investigating cost-effective harvesting and extraction methods suitable for a variety of species and conditions. Areas of expertise include cell wall analysis and deconstruction and identification and utilization of co-products. (4) Fuel Conversion - NREL's excellent capabilities and facilities for biochemical and thermochemical conversion of biomass to biofuels are being

  18. Measuring the Composition and Stable-Isotope Labeling of Algal Biomass Carbohydrates via Gas Chromatography/Mass Spectrometry.

    PubMed

    McConnell, Brian O; Antoniewicz, Maciek R

    2016-05-01

    We have developed a method to measure carbohydrate composition and stable-isotope labeling in algal biomass using gas chromatography/mass spectrometry (GC/MS). The method consists of two-stage hydrochloric acid hydrolysis, followed by chemical derivatization of the released monomer sugars and quantification by GC/MS. Fully (13)C-labeled sugars are used as internal standards for composition analysis. This convenient, reliable, and accurate single-platform workflow offers advantages over existing methods and opens new opportunities to study carbohydrate metabolism of algae under autotrophic, mixotrophic, and heterotrophic conditions using metabolic flux analysis and isotopic tracers such as (2)H2O and (13)C-glucose. PMID:27042946

  19. Composition, buoyancy regulation and fate of ice algal aggregates in the Central Arctic Ocean.

    PubMed

    Fernández-Méndez, Mar; Wenzhöfer, Frank; Peeken, Ilka; Sørensen, Heidi L; Glud, Ronnie N; Boetius, Antje

    2014-01-01

    Sea-ice diatoms are known to accumulate in large aggregates in and under sea ice and in melt ponds. There is recent evidence from the Arctic that such aggregates can contribute substantially to particle export when sinking from the ice. The role and regulation of microbial aggregation in the highly seasonal, nutrient- and light-limited Arctic sea-ice ecosystem is not well understood. To elucidate the mechanisms controlling the formation and export of algal aggregates from sea ice, we investigated samples taken in late summer 2011 and 2012, during two cruises to the Eurasian Basin of the Central Arctic Ocean. Spherical aggregates densely packed with pennate diatoms, as well as filamentous aggregates formed by Melosira arctica showed sign of different stages of degradation and physiological stoichiometries, with carbon to chlorophyll a ratios ranging from 110 to 66700, and carbon to nitrogen molar ratios of 8-35 and 9-40, respectively. Sub-ice algal aggregate densities ranged between 1 and 17 aggregates m(-2), maintaining an estimated net primary production of 0.4-40 mg C m(-2) d(-1), and accounted for 3-80% of total phototrophic biomass and up to 94% of local net primary production. A potential factor controlling the buoyancy of the aggregates was light intensity, regulating photosynthetic oxygen production and the amount of gas bubbles trapped within the mucous matrix, even at low ambient nutrient concentrations. Our data-set was used to evaluate the distribution and importance of Arctic algal aggregates as carbon source for pelagic and benthic communities. PMID:25208058

  20. Composition, Buoyancy Regulation and Fate of Ice Algal Aggregates in the Central Arctic Ocean

    PubMed Central

    Fernández-Méndez, Mar; Wenzhöfer, Frank; Peeken, Ilka; Sørensen, Heidi L.; Glud, Ronnie N.; Boetius, Antje

    2014-01-01

    Sea-ice diatoms are known to accumulate in large aggregates in and under sea ice and in melt ponds. There is recent evidence from the Arctic that such aggregates can contribute substantially to particle export when sinking from the ice. The role and regulation of microbial aggregation in the highly seasonal, nutrient- and light-limited Arctic sea-ice ecosystem is not well understood. To elucidate the mechanisms controlling the formation and export of algal aggregates from sea ice, we investigated samples taken in late summer 2011 and 2012, during two cruises to the Eurasian Basin of the Central Arctic Ocean. Spherical aggregates densely packed with pennate diatoms, as well as filamentous aggregates formed by Melosira arctica showed sign of different stages of degradation and physiological stoichiometries, with carbon to chlorophyll a ratios ranging from 110 to 66700, and carbon to nitrogen molar ratios of 8–35 and 9–40, respectively. Sub-ice algal aggregate densities ranged between 1 and 17 aggregates m−2, maintaining an estimated net primary production of 0.4–40 mg C m−2 d−1, and accounted for 3–80% of total phototrophic biomass and up to 94% of local net primary production. A potential factor controlling the buoyancy of the aggregates was light intensity, regulating photosynthetic oxygen production and the amount of gas bubbles trapped within the mucous matrix, even at low ambient nutrient concentrations. Our data-set was used to evaluate the distribution and importance of Arctic algal aggregates as carbon source for pelagic and benthic communities. PMID:25208058

  1. Capillary Electrophoresis Single-Strand Conformational Polymorphisms as a Method to Differentiate Algal Species.

    PubMed

    Jernigan, Alice; Hestekin, Christa

    2015-01-01

    Capillary electrophoresis single-strand conformational polymorphism (CE-SSCP) was explored as a fast and inexpensive method to differentiate both prokaryotic (blue-green) and eukaryotic (green and brown) algae. A selection of two blue-green algae (Nostoc muscorum and Anabaena inaequalis), five green algae (Chlorella vulgaris, Oedogonium foveolatum, Mougeotia sp., Scenedesmus quadricauda, and Ulothrix fimbriata), and one brown algae (Ectocarpus sp.) were examined and CE-SSCP electropherogram "fingerprints" were compared to each other for two variable regions of either the 16S or 18S rDNA gene. The electropherogram patterns were remarkably stable and consistent for each particular species. The patterns were unique to each species, although some common features were observed between the different types of algae. CE-SSCP could be a useful method for monitoring changes in an algae species over time as potential shifts in species occurred. PMID:26101693

  2. Capillary Electrophoresis Single-Strand Conformational Polymorphisms as a Method to Differentiate Algal Species

    PubMed Central

    Jernigan, Alice; Hestekin, Christa

    2015-01-01

    Capillary electrophoresis single-strand conformational polymorphism (CE-SSCP) was explored as a fast and inexpensive method to differentiate both prokaryotic (blue-green) and eukaryotic (green and brown) algae. A selection of two blue-green algae (Nostoc muscorum and Anabaena inaequalis), five green algae (Chlorella vulgaris, Oedogonium foveolatum, Mougeotia sp., Scenedesmus quadricauda, and Ulothrix fimbriata), and one brown algae (Ectocarpus sp.) were examined and CE-SSCP electropherogram “fingerprints” were compared to each other for two variable regions of either the 16S or 18S rDNA gene. The electropherogram patterns were remarkably stable and consistent for each particular species. The patterns were unique to each species, although some common features were observed between the different types of algae. CE-SSCP could be a useful method for monitoring changes in an algae species over time as potential shifts in species occurred. PMID:26101693

  3. Toxicity of algal-derived aldehydes to two invertebrate species: do heavy metal pollutants have a synergistic effect?

    PubMed

    Taylor, Rebecca L; Caldwell, Gary S; Bentley, Matthew G

    2005-08-15

    The recent discovery of the production of anti-proliferative aldehydes in a variety of microalgal species has lead to considerable investigation into the effects of these toxins on aquatic invertebrates. Studies have, however, rarely considered the impact pollutants may have on grazer responses to algal toxins. In this study, the acute toxicities of five aldehydes to the rotifer Brachionus plicatilis and nauplii of the brine shrimp Artemia salina are examined using immersion assays. In addition, the effect of a representative of these aldehydes in the presence of sub-lethal levels of heavy metals was examined. B. plicatilis generally showed greater sensitivity to the aldehydes than A. salina. The polyunsaturated 2-trans,4-trans-decadienal was the most toxic to both species having 24h LD(50) values of 7 and 20 microM for B. plicatilis and A. salina, respectively. The remaining aldehydes had different orders of toxicity for the two species with a stronger relationship observed between mortality and aldehyde carbon-chain length for A. salina whereas B. plicatilis mortality showed a stronger dependence on the presence of carbon-carbon double bonds in the aldehydes. The presence of 1 microM of copper sulphate in solutions of decadienal resulted in the reduction of the 24h LD(50) of decadienal by approximately a third for both species. 1 microM of copper chloride in solutions of decadienal reduced the 24h LD(50) of decadienal to A. salina nauplii by approximately 11% and 1 microM zinc sulphate caused a reduction of only 3%. Pre-exposure of the organisms to 1 microM copper sulphate had no significant impact on their subsequent mortality in decadienal. The ecological implications and the possible mechanisms for the action of copper sulphate on the response of organisms to decadienal are discussed. PMID:15927283

  4. Treatment of Dairy and Swine Manure Effluents Using Freshwater Algae: Fatty Acid Content and Composition of Algal Biomass at Different Manure Loading Rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An alternative to land spreading of manure effluents is to grow crops of algae on the N and P present in the manure and convert manure N and P into algal biomass. The objective of this study was to determine how fatty acid (FA) content and composition of algae respond to changes in the type of manu...

  5. The Seeding and Cultivation of a Tropical Species of Filamentous Ulva for Algal Biomass Production

    PubMed Central

    Carl, Christina; de Nys, Rocky; Paul, Nicholas A.

    2014-01-01

    Filamentous species of Ulva are ideal for cultivation because they are robust with high growth rates and maintained across a broad range of environments. Temperate species of filamentous Ulva are commercially cultivated on nets which can be artificially ‘seeded’ under controlled conditions allowing for a high level of control over seeding density and consequently biomass production. This study quantified for the first time the seeding and culture cycle of a tropical species of filamentous Ulva (Ulva sp. 3) and identified seeding density and nursery period as key factors affecting growth and biomass yield. A seeding density of 621,000 swarmers m-1 rope in combination with a nursery period of five days resulted in the highest growth rate and correspondingly the highest biomass yield. A nursery period of five days was optimal with up to six times the biomass yield compared to ropes under either shorter or longer nursery periods. These combined parameters of seeding density and nursery period resulted in a specific growth rate of more than 65% day−1 between 7 and 10 days of outdoor cultivation post-nursery. This was followed by a decrease in growth through to 25 days. This study also demonstrated that the timing of harvest is critical as the maximum biomass yield of 23.0±8.8 g dry weight m−1 (228.7±115.4 g fresh weight m−1) was achieved after 13 days of outdoor cultivation whereas biomass degraded to 15.5±7.3 g dry weight m−1 (120.2±71.8 g fresh weight m−1) over a longer outdoor cultivation period of 25 days. Artificially seeded ropes of Ulva with high biomass yields over short culture cycles may therefore be an alternative to unattached cultivation in integrated pond-based aquaculture systems. PMID:24897115

  6. Effect of phosphorous concentrations on sedimentary distributions and isotopic composition of algal lipid biomarkers in lakes from central Switzerland

    NASA Astrophysics Data System (ADS)

    Ladd, N.; Dubois, N.; Schubert, C. J.

    2015-12-01

    Lakes in the Swiss central plateau experienced increasing anthropogenic phosphorous loading throughout much of the 20th century. Since the 1980s concerted remediation efforts on the part of the Swiss government have significantly reduced P concentrations in most lakes and reversed previous eutrophication. However, P concentrations remain elevated above their preindustrial levels in many sites. High quality monitoring of lake nutrient levels since the 1950s, along with several lakes of wide-ranging P concentrations in close proximity, make central Switzerland an ideal location for studying the ways in which nutrient loading affects the organic composition of lacustrine sediments. Results of such studies can be used to develop proxies of eutrophication in sites where fewer historical data exist, and to reconstruct historical P concentrations in local lakes from the time before record keeping began. We analyzed the distributions of algal lipid biomarkers from surface sediment and sediment traps collected in the spring of 2015 from ten lakes with variable P concentrations in central Switzerland. Sedimentary lipid distributions from these lakes confirm that biomarkers associated with algal and cyanobacterial sources are more abundant in the sediment of lakes with greater P loading. The dry sedimentary concentrations of biomarkers such as brassicasterol (primarily diatom source) and diplopterol (cyanobacteria source), as well as the less source specific short-chain n-alkanols, linearly increase from 0.3 - 1.9 μg/g as total phosphorous in the upper water column increases by 1 μg/L over a range of 7 - 50 μg/L. We also present preliminary hydrogen isotope data from these biomarkers. Hydrogen isotopes of algal lipids primarily reflect the source water in which the algae grew, and this relationship has been developed as a paleohydrologic proxy. However, laboratory cultures of marine algae demonstrate that they discriminate more against 2H under nutrient replete conditions

  7. The chemistry and immunochemistry of carrageenans from Eucheuma and related algal species.

    PubMed

    DiNinno, V; McCandless, E L

    1978-10-01

    Carrageenans from several species of Eucheuma have been fractionated into KC1-soluble and KC1-insoluble fractions and analyzed by the usual chemical procedures. An anti-kappa-carrageenan, the reactivity of which is directed to kappa-structures (i.e., 3-linked galactose 4-sulphate, and 4-linked 3,6-anhydrogalactose) was used to analyze these carrageenans immunochemically. The antibody preparation shows only a small amount of cross-reactivity with iota-type carrageenans and thus could be used to distinguish kappa- and iota-type carrageenans, the latter having an index of homology of less than 0.2. A comparison of chemical and immunochemical data yielded further information as to the nature of the carrageenan-anti-carrageenan interaction, as well as elucidating the finer structure of carrageenans. PMID:698982

  8. Induction of reactive oxygen species and algal growth inhibition by tritiated water with or without copper.

    PubMed

    Réty, C; Gilbin, R; Gomez, E

    2012-03-01

    Tritium ((3) H) is a radioactive element of ecological concern because of its release into aquatic ecosystems from nuclear power plants. However, the acute and chronic effects of tritiated water (HTO) on aquatic organisms are poorly documented, as are its effects on oxidative stress. In addition, the effects of HTO in combination with other contaminants remain largely unexamined. Herein, we document the effect of HTO on a primary aquatic producer (Chlamydomonas reinhardtii) by measuring growth and oxidative stress using fluorimetric (H(2) DCF-DA) determination of Reactive Oxygen Species (ROS) production. The maximum cell density of the alga (1.65 × 10(6) cells mL(-1) ) was reduced by 23% (1.27 × 10(6) cells mL(-1) ) at the highest exposure tested (59 MBq mL(-1) HTO), whereas cells exposed to 0.9 MBq mL(-1) showed a significantly enhanced maximum cell density of 1.90 × 10(6) cells mL(-1) , an increase of 15%. With regard to oxidative stress, exposure to HTO (0.04, 0.16, and 2.8 MBq mL(-1) ) induced an early dose-dependent peak in ROS production after 14-15 min of exposure, followed by a slow decrease in ROS which stabilized after 60 min. Moreover, this study showed that the presence of HTO may influence the impact of other conventional, nonradioactive contaminants, such as copper, a well known oxidizing trace metal for aquatic organisms. A significant synergic effect of copper and HTO on ROS production was observed. This synergic effect on oxidative stress was shown to be linked to an enhanced copper uptake rate measured in the presence of HTO (> 4 times). We conclude that HTO should be considered as a sensitizer when in a mixture with other contaminants, especially through interactions on the antioxidant system of algae. PMID:20607814

  9. Estimation of herbicide species sensitivity distribution using single-species algal toxicity data and information on the mode of action.

    PubMed

    Nagai, Takashi; Taya, Kiyoshi

    2015-03-01

    Although species sensitivity distribution (SSD) is a key concept for quantitative ecological risk assessment, its application is limited owing to a lack of sufficient data for the analysis, especially on the toxicity of herbicides for primary producers. The authors developed a method of herbicide SSD estimation using single-species toxicity data and information on the herbicide mode of action. The authors' method was based on 2 assumptions: the slopes of the SSD of the same MOA herbicides are the same and the relative sensitivities of standard algae in the SSD of the same MOA herbicides are the same. The 2 parameters of log-normal SSD, mean sensitivity, and variation in sensitivity, for 92 herbicides were determined to establish the estimation model. Mean sensitivities were linearly correlated with logarithmic 50% effect concentrations (EC50) for standard algae. The average of variations in sensitivity significantly differed among MOA, and variations in sensitivity were constant independently of EC50 values for standard algae for the same MOA herbicides. These results were all consistent with the assumptions of the SSD estimation method. The outcome was validated by comparing the estimated SSDs using the proposed method with the generated SSDs using toxicity data which were independent of method development. These SSDs were consistent, and considering MOA information improved the accuracy of estimating SSD markedly. PMID:25475367

  10. Algicidal Effects of a Novel Marine Pseudoalteromonas Isolate (Class Proteobacteria, Gamma Subdivision) on Harmful Algal Bloom Species of the Genera Chattonella, Gymnodinium, and Heterosigma

    PubMed Central

    Lovejoy, Connie; Bowman, John P.; Hallegraeff, Gustaaf M.

    1998-01-01

    During a bacterial survey of the Huon Estuary in southern Tasmania, Australia, we isolated a yellow-pigmented Pseudoalteromonas strain (class Proteobacteria, gamma subdivision), designated strain Y, that had potent algicidal effects on harmful algal bloom species. This organism was identified by 16S rRNA sequencing as a strain with close affinities to Pseudoalteromonas peptidysin. This bacterium caused rapid cell lysis and death (within 3 h) of gymnodinoids (including Gymnodinium catenatum) and raphidophytes (Chattonella marina and Heterosigma akashiwo). It caused ecdysis of armored dinoflagellates (e.g., Alexandrium catenella, Alexandrium minutum, and Prorocentrum mexicanum), but the algal cultures then recovered over the subsequent 24 h. Strain Y had no effect on a cryptomonad (Chroomonas sp.), a diatom (Skeletonema sp.), a cyanobacterium (Oscillatoria sp.), and two aplastidic protozoans. The algicidal principle of strain Y was excreted into the seawater medium and lost its efficacy after heating. Another common bacterial species, Pseudoalteromonas carrageenovora, was isolated at the same time and did not have these algicidal effects. The minimum concentrations of strain Y required to kill G. catenatum were higher than the mean concentrations found in nature under nonbloom conditions. However, the new bacterium showed a chemotactic, swarming behavior that resulted in localized high concentrations around target organisms. These observations imply that certain bacteria could play an important role in regulating the onset and development of harmful algal blooms. PMID:9687434

  11. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    SciTech Connect

    Samson, R.; LeDuy, A.

    1982-08-01

    The photosynthetic spectrum of solar energy could be exploited for the production of chemical energy of methane through the combined algal-bacterial process. In this process, the algae are mass produced from light and from carbon in the first step. The algal biomass is then used as a nutrient for feeding the anaerobic digester, in the second step, for the production of methane by anaerobic bacteria. The carbon source for the production of algal biomass could be either organic carbon from wastewaters (for eucaryotic algae), or carbon dioxide from the atmosphere or from the combustion exhaust gases (for both prokaryotic and eukaryotic algae). The technical feasibility data on the anaerobic digestion of algal biomass have been reported for many species of algae including macroscopic algae and microscopic algae. Research being conducted in the authors' laboratory consists of using the semimicroscopic blue-green alga Spirulina maxima as the sole substrate for this combined algal-bacterial process. This species of alga is very attractive for the process because of its capability of using the atmospheric carbon dioxide as carbon source and its simple harvesting methods. Furthermore, it appeared that the fermentability of S. maxima is significantly higher than other microscopic algae. This communication presents the results on the anaerobic inoculum development by the adaptation technique. This inoculum was then used for the semicontinuous anaerobic digestion of S. maxima algal biomass. The evolutions of biogas production and composition, biogas yield, total volatile fatty acids, alkalinity, ammonia nitrogen, pH, and electrode potential were followed.

  12. Kelp canopy facilitates understory algal assemblage via competitive release during early stages of secondary succession.

    PubMed

    Benes, Kylla M; Carpenter, Robert C

    2015-01-01

    Kelps are conspicuous foundation species in marine ecosystems that alter the composition of understory algal assemblages. While this may be due to changes in the competitive interactions between algal species, how kelp canopies mediate propagule supply and establishment success of understory algae is not well known. In Southern California, USA, Eisenia arborea forms dense kelp canopies in shallow subtidal environments and is associated with an understory dominated by red algal species. In canopy-free areas, however, the algal assemblage is comprised of mostly brown algal species. We used a combination of mensurative and manipulative experiments to test whether Eisenia facilitates the understory assemblage by reducing competition between these different types of algae by changes in biotic interactions and/or recruitment. Our results show Eisenia facilitates a red algal assemblage via inhibition of brown algal settlement into the canopy zone, allowing recruitment to occur by vegetative means rather than establishment of new individuals. In the canopy-free zone, however, high settlement and recruitment rates suggest competitive interactions shape the community there. These results demonstrate that foundation species alter the distribution and abundance of associated organisms by affecting not only interspecific interactions but also propagule supply and recruitment limitation. PMID:26236909

  13. DNA barcoding unmasks overlooked diversity improving knowledge on the composition and origins of the Churchill algal flora

    PubMed Central

    2013-01-01

    Background Sampling expeditions to Churchill in the Canadian subarctic were completed with the aim of compiling a molecular-assisted survey of the macroalgal flora (seaweeds) for comparison to published accounts for this area, which are based on morphological identifications. Further, because the Churchill region was covered by ice until recently (~10,000 before present), the current algal flora has had to migrate from adjacent waters into that region. We used our DNA barcode data to predict the relative contribution of the North Atlantic and North Pacific floras (Likely Source Region) in repopulating the Churchill region following the most recent glacial retreat. Results We processed 422 collections representing ~50 morpho-species, which is the approximate number reported for this region, and generated DNA barcode data for 346 of these. In contrast to the morpho-species count, we recovered 57 genetic groups indicating overlooked species (this despite failing to generate barcode data for six of the ~50 morpho-species). However, we additionally uncovered numerous inconsistencies between the species that are currently listed in the Churchill flora (again as a result of overlooked species diversity, but combined with taxonomic confusion) and those identified following our molecular analyses including eight new records and another 17 genetic complexes in need of further study. Based on a comparison of DNA barcode data from the Churchill flora to collections from the contiguous Atlantic and Pacific floras we estimate that minimally 21% (possibly as much as 44%) of the Churchill flora was established by migration from the Pacific region with the balance of species arriving from the Atlantic (predominantly North American populations) following the last glacial retreat. Conclusions Owing to difficulties associated with the morphological identification of macroalgae, our results indicate that current comprehension of the Canadian Arctic flora is weak. We consider that

  14. Essential Oil Composition of Three Globularia Species.

    PubMed

    Crkvenčić, Maja; Dudaš, Slavica; Jerković, Igor; Marijanović, Zvonimir; Poljuha, Danijela; Pilepić, Kroata Hazler

    2016-02-01

    The chemical composition of the essential oils obtained by hydrodistillation from the aerial parts of Globularia cordifolia L., G. meridionalis (Podp.) O.Schwarz, and G. punctata Lapeyr. was characterized by GC-FID and GC/MS analyses. Among the 33 identified compounds, the most abundant present in all investigated samples were oct-1-en-3-ol (2.9-47.0%), 6-(1,5-dimethylhex-4-enyl)-3-methylcyclohex-2-enone (8.2-40.9%), and fukinanolid (7.4-31.6%). Multivariate statistical analyses (PCA and HCA) of the hitherto studied Globularia volatile compounds confirmed to some extent the assumed phylogenetic relationships of the Globularia species studied, including the close relationship between the morphologically similar species G. cordifolia and G. meridionalis, but also evidenced several discrepancies in the current classification of Globularia species. PMID:26880434

  15. Algal biofuels from wastewater treatment high rate algal ponds.

    PubMed

    Craggs, R J; Heubeck, S; Lundquist, T J; Benemann, J R

    2011-01-01

    This paper examines the potential of algae biofuel production in conjunction with wastewater treatment. Current technology for algal wastewater treatment uses facultative ponds, however, these ponds have low productivity (∼10 tonnes/ha.y), are not amenable to cultivating single algal species, require chemical flocculation or other expensive processes for algal harvest, and do not provide consistent nutrient removal. Shallow, paddlewheel-mixed high rate algal ponds (HRAPs) have much higher productivities (∼30 tonnes/ha.y) and promote bioflocculation settling which may provide low-cost algal harvest. Moreover, HRAP algae are carbon-limited and daytime addition of CO(2) has, under suitable climatic conditions, the potential to double production (to ∼60 tonnes/ha.y), improve bioflocculation algal harvest, and enhance wastewater nutrient removal. Algae biofuels (e.g. biogas, ethanol, biodiesel and crude bio-oil), could be produced from the algae harvested from wastewater HRAPs, The wastewater treatment function would cover the capital and operation costs of algal production, with biofuel and recovered nutrient fertilizer being by-products. Greenhouse gas abatement results from both the production of the biofuels and the savings in energy consumption compared to electromechanical treatment processes. However, to achieve these benefits, further research is required, particularly the large-scale demonstration of wastewater treatment HRAP algal production and harvest. PMID:21330711

  16. Interactions between macro-algal mats and invertebrates in the Ythan estuary, Aberdeenshire, Scotland

    NASA Astrophysics Data System (ADS)

    Raffaelli, D.

    2000-07-01

    Blooms of opportunistic green macro-algae are a common feature of coastal areas and their effects on mudflat invertebrates can be dramatic. On the Ythan estuary, Aberdeenshire, Scotland, we have carried out a number of manipulative field experiments designed to evaluate the effects on invertebrates of different species of macro-algae with contrasting ecologies, and the effects of invertebrates on the development of the blooms. Macro-algal mats were found to have dramatic nega- tive effects on the density of the amphipod Corophium volutator, with higher algal biomasses having greater impact. The mechanism for this interaction seems to be interference by the algal filaments with the feeding behaviour of the amphipod. In contrast, the polychaete Capitella spp. increases in abundance under macro-algal mats due to enrichment of the sediment with organic material. These two interactions are seen at all scales, in areas of less than 1 m2 to the scale of the entire estuary, irrespective of the species composition of the macro- algal mats. Bioturbation by Corophium and grazing by the snail Hydrobia ulvae had little effect on macro-algal biomass, but there were less algae when the polychaete Nereis diversicolor was present. The most significant interaction in this system is the pronounced negative impact of algal mats on the abundance of Corophium, probably the most important invertebrate species in the diets of the estuary's shorebirds, fish and epibenthic crustaceans.

  17. Seasonal variations in biomass and species composition of seaweeds along the northern coasts of Persian Gulf (Bushehr Province)

    NASA Astrophysics Data System (ADS)

    Dadolahi-Sohrab, A.; Garavand-Karimi, M.; Riahi, H.; Pashazanoosi, H.

    2012-02-01

    This study was carried out to evaluate the seasonal variations of seaweed biomass and species composition at six different sites along the coastal areas in Bushehr Province. Sampling depths varied among sites, from 0.3 to 2.0 m below mean sea level. A total of 37 (i.e., 10 Chlorophyta, 12 Phaeophyta and 15 Rhodophyta) seaweed species were collected. Studies were conducted for quantifying the seaweeds during four seasons from October 2008 until July 2009. During present research, Ulva intestinalis and Cladophora nitellopsis of green, Polycladia myrica, Sirophysalia trinodis and Sargassum angustifolium of brown and Gracilaria canaliculata and Hypnea cervicornis of red seaweeds showed highest biomass in coastal areas of Bushehr Province. The Cheney`s ratio of 2.1 indicated a temperate algal flora to this area. All sites exhibited more than 50% similarity of algal species, indicating a relatively homogenous algal distribution. Total biomass showed the highest value of 3280.7 ± 537.8 g dry wt m - 2 during summer and lowest value of 856.9 ± 92.0 g dry wt m - 2 during winter. During this study, the highest and lowest seaweed biomass were recorded on the site 2 (2473.7 ± 311.0 g dry wt m - 2) and site 5 (856.7 ± 96.8 g dry wt m - 2), respectively.

  18. Formation of insoluble, nonhydrolyzable, sulfur-rich macromolecules via incorporation of inorganic sulfur species into algal carbohydrates

    NASA Astrophysics Data System (ADS)

    Kok, Marika D.; Schouten, Stefan; Sinninghe Damsté, Jaap S.

    2000-08-01

    The process of sulfur incorporation into organic matter was simulated in the laboratory by sulfurization of cell material of the prymnesiophyte alga Phaeocystis in sea water with inorganic polysulfides at 50°C. Flash pyrolysis of the residue, obtained after extraction and several hydrolysis steps, yielded mainly C 1-C 4 alkylbenzenes and C 1-C 4 alkylphenols and, in contrast to control and blank experiments, relatively high amounts of C 0-C 4 alkylthiophenes. The distribution of the thiophenes is very similar to that in pyrolysates of type II-S kerogens. The formation of high-molecular-weight sulfur-rich macromolecules co-occurs with a marked drop in the content of hydrolyzable carbohydrates. This indicates that sulfurization results in the preservation of algal carbohydrate carbon in a macromolecular structure composed of (poly)sulfidic cross-linked carbohydrate skeletons, which upon pyrolysis yields alkylthiophenes. Sulfurization of glucose under similar conditions resulted in the formation of a nonhydrolyzable, solid material, which yielded high amounts of organic sulfur compounds upon pyrolysis, mainly short-chain alkylthiophenes, although with a different distribution than that in the pyrolysate of the sulfurized algal material. The carbon numbers of these organic sulfur compounds extend beyond six, indicating that the length of the carbon skeleton of the pyrolysis products is not limited by the length of the carbon skeleton of the substrate. These results suggest that the sulfurization of carbohydrates may be an important pathway in the preservation of organic matter in euxinic depositional environments.

  19. Development and evaluation of a DNA microarray assay for the simultaneous detection of nine harmful algal species in ship ballast and seaport waters

    NASA Astrophysics Data System (ADS)

    Chen, Xianfeng; Zhou, Qianjin; Duan, Weijun; Zhou, Chengxu; Duan, Lijun; Zhang, Huili; Sun, Aili; Yan, Xiaojun; Chen, Jiong

    2016-01-01

    Rapid, high-throughput and reliable methods are urgently required to accurately detect and monitor harmful algae, which are responsible for algal blooms, such as red and green tides. In this study, we successfully developed a multiplex PCR-based DNA microarray method capable of detecting nine harmful algal species simultaneously, namely Alexandrium tamarense, Gyrodinium instriatum, Heterosigma akashiwo, Karenia mikimotoi, Prorocentrum donghaiense, Prorocentrum minimum, Ulva compressa, Ulva ohnoi and Ulva prolifera. This method achieved a limit of detection (LOD) of 0.5 ng of genomic DNA (orders of magnitude of the deci-nanogram range) in the tested algae cultures. Altogether, 230 field samples from ship ballast waters and seaport waters were used to evaluate the DNA microarray. The clinical sensitivity and specificity of the DNA microarray assay in detecting field samples were 96.4% and 90.9%, respectively, relative to conventional morphological methods. This indicated that this high-throughput, automatic, and specific method is well suited for the detection of algae in water samples.

  20. Structural Impacts on Thallus and Algal Cell Components of Two Lichen Species in Response to Low-Level Air Pollution in Pacific Northwest Forests

    NASA Astrophysics Data System (ADS)

    Ra, Hyung-Shim Y.; Rubin, Laura; Crang, Richard F. E.

    2004-04-01

    Lichens have long been regarded as bioindicators of air pollution, and structural studies typically have indicated negative impacts in highly polluted areas. In this research, Parmelia sulcata and Platismatia glauca were collected from one clean and two polluted sites in the Pacific Northwest forests of the United States to investigate the anatomical and ultrastructural responses of relatively resistant lichens to moderate air pollution. Light microscopy of polluted materials revealed only slight increases in the algal cell proportions of the thallus, and a decrease in the fungal cells of the medulla. Using transmission electron microscopy, increased lipid droplets in the cytoplasm and an increase in the cell wall thickness of the photobionts were found in the polluted lichens. These results were compared with physiological data in which the net carbon uptake did not show any significant differences; however, the total chlorophyll content was heightened in the polluted samples. The increased total chlorophyll content and the absence of any changes in the algal cell proportions of the polluted samples suggest that the photobionts possessed a higher chlorophyll content per unit volume of the photobiont at polluted sites. The results also indicate that lichens have altered their storage allocation in different cellular compartments. This may be a result of symbiotic readjustment(s) between the photobiont and the mycobiont. In comparison with the physiological results from these two species, these changes do not represent damaging effects by low-level air pollution.

  1. A comparison of the influences of urbanization in contrasting environmental settings on stream benthic algal assemblages

    USGS Publications Warehouse

    Potapova, M.; Coles, J.F.; Giddings, E.M.P.; Zappia, H.

    2005-01-01

    Patterns of stream benthic algal assemblages along urbanization gradients were investigated in three metropolitan areas-Boston (BOS), Massachusetts; Birmingham (BIR), Alabama; and Salt Lake City (SLC), Utah. An index of urban intensity derived from socioeconomic, infrastructure, and land-use characteristics was used as a measure of urbanization. Of the various attributes of the algal assemblages, species composition changed along gradients of urban intensity in a more consistent manner than biomass or diversity. In urban streams, the relative abundance of pollution-tolerant species was often higher than in less affected streams. Shifts in assemblage composition were associated primarily with increased levels of conductivity, nutrients, and alterations in physical habitat. Water mineralization and nutrients were the most important determinants of assemblage composition in the BOS and SLC study areas; flow regime and grazers were key factors in the BIR study area. Species composition of algal assemblages differed significantly among geographic regions, and no particular algal taxa were found to be universal indicators of urbanization. Patterns in algal biomass and diversity along urban gradients varied among study areas, depending on local environmental conditions and habitat alteration. Biomass and diversity increased with urbanization in the BOS area, apparently because of increased nutrients, light, and flow stability in urban streams, which often are regulated by dams. Biomass and diversity decreased with urbanization in the BIR study area because of intensive fish grazing and less stable flow regime. In the SLC study area, correlations between algal biomass, diversity, and urban intensity were positive but weak. Thus, algal responses to urbanization differed considerably among the three study areas. We concluded that the wide range of responses of benthic algae to urbanization implied that tools for stream bioassessment must be region specific. ?? 2005 by the

  2. Use of a mixed algal culture to characterize industrial waste waters

    SciTech Connect

    Claesson, A.

    1984-02-01

    A mixture of five freshwater algae was cultivated with additions of waste water samples from chemical, mining, polyvinylchloride, textile, paper mill, and oil refinery industries. Two water samples from chemical industries and one from an oil refinery stimulated the algal growth in a nutrient-poor medium, while growth in other samples, including a nutrient-rich medium, was inhibited in several different ways. For eight of the water samples a delayed growth of 2-4 days was noted. Decreased growth rate and lowered maximal biomass occurred in seven of the samples. The photosynthetic capacity of the algal cells was measured by using in vivo fluorescence of chlorophyll a. These quick measurements mostly agreed with those of the growth rates. When the species composition of the mixed algal culture was investigated, large differences in sensitivities between the different species were found. Stimulation or inhibition were observed in the same sample for different species but also for the same species at different concentrations.

  3. Short-term temporal dynamics of algal species in a subtidal kelp bed in relation to changes in environmental conditions and canopy biomass

    NASA Astrophysics Data System (ADS)

    Wernberg, Thomas; Goldberg, Nisse

    2008-01-01

    Understanding temporal variation at the scale of weeks to months is critical to understanding broad temporal patterns in diversity in the same way as understanding diversity across landscapes relies on understanding variation at the scale of meters. However, whereas small-scale spatial variation in temperate reef algal assemblages has been extensively studied, fine-scale temporal changes have not been well addressed. By sampling the macroalgae of a subtidal reef near Perth (Australia), dominated by the small kelp Ecklonia radiata, every ˜40 days over a 2-year period, we were able to test whether temporal changes in species richness, assemblage structure and species turn-over were related to seasonal changes in surface temperature, solar radiation and wave height. A total of 93 macroalgal taxa were identified, and species richness per sampling time ranged from 25 to 64 taxa 1.25 m -2. Biomass of E. radiata was positively correlated with changes in sea surface temperature and light, and negatively correlated with wave height. Species richness, assemblage structure and turn-over of other macroalgae were more associated with seasonal changes in kelp biomass than environmental variables per se. We conclude that seasonal changes in environmental conditions drive changes in the kelp canopy, which in turn drive changes in species richness and assemblage structure. This suggests that habitat-formers such as kelps can exert a strong temporal influence on associated communities, analogous to well-described spatial influences. Thus, as kelp canopy biomass expands and retracts over time-scales of weeks to months, so does available space for colonization and growth, resulting in a high species turn-over. Species richness is therefore increased and maintained through time, in the same way as canopy-gap mosaics increase and maintain species richness across spatial landscapes.

  4. Phytochip: development of a DNA-microarray for rapid and accurate identification of Pseudo-nitzschia spp and other harmful algal species.

    PubMed

    Noyer, Charlotte; Abot, Anne; Trouilh, Lidwine; Leberre, Véronique Anton; Dreanno, Catherine

    2015-05-01

    Detection of harmful algal blooms has become a challenging concern because of the direct impacts on public health and economy. The identification of toxic dinoflagellates and diatoms in monitoring programs requires an extensive taxonomic expertise and is time consuming. Advances in molecular biology have allowed the development of new approaches, more rapid, accurate and cost-effective for detecting these microorganisms. In this context, we developed a new DNA microarray (called, Phytochip) for the simultaneous detection of multiple HAB species with a particular emphasis on Pseudo-nitzschia species. Oligonucleotide probes were designed along the rRNA operon. After DNA extraction, the target rDNA genes were amplified and labeled using an asymmetric PCR; then, the amplicons were hybridized to the oligonucleotide probes present on the chips. The total assay from seawater sampling to data acquisition can be performed within a working day. Specificity and sensitivity were assessed by using monoclonal cultures, mixtures of species and field samples spiked with a known amount of cultured cells. The Phytochip with its 81 validated oligonucleotide probes was able to detect 12 species of Pseudo-nitzschia and 11 species of dinoflagellates among which were 3 species of Karenia and 3 species of Alexandrium. The Phytochip was applied to environmental samples already characterized by light microscopy and cloned into DNA libraries. The hybridizations on the Phytochip were in good agreement with the sequences retrieved from the clone libraries and the microscopic observations. The Phytochip enables a reliable multiplex detection of phytoplankton and can assist a water quality monitoring program as well as more general ecological research. PMID:25765159

  5. Streptomyces alboflavus RPS and Its Novel and High Algicidal Activity against Harmful Algal Bloom Species Phaeocystis globosa

    PubMed Central

    Wang, Haitao; Li, Dong; Yang, Xujun; An, Xinli; Zheng, Xiaowei; Tian, Yun; Zheng, Wei; Zheng, Tianling

    2014-01-01

    Phaeocystis globosa blooms have frequently occurred along coastal waters and exerted serious impacts on ecological environments by releasing toxic hemolytic substances, forming nuisance foam, and causing oxygen depletion. An actinomycete strain RPS with high algicidal activity against P. globosa was isolated and identified as Streptomyces alboflavus, based on morphology, physiological and biochemical characteristics, and 16S rDNA sequence analysis. RPS lysed 95% of P. globosa within 48 h by releasing an extracellular active substance into the growth medium. The activity of RPS supernatant was sensitive to temperature at and above 50°C and insensitive to pH from 3 to 11. The molecular weight of the active substance was between 100 Da and 1000 Da, and approximately 90% of it was extracted by ethyl acetate. It was presumed that the active component efficiently inhibited the movement of P. globosa, caused the flagella to fall off the algae, and finally lysed the algal cells. RPS showed a wide target range against harmful algae. S. alboflavus RPS with high algicidal activity and such novel features of temperature and pH sensitivity, low molecular weight, algicidal process, and target range possesses great potential in the biological control of P. globosa blooms. PMID:24675867

  6. Streptomyces alboflavus RPS and its novel and high algicidal activity against harmful algal bloom species Phaeocystis globosa.

    PubMed

    Zhang, Bangzhou; Cai, Guanjing; Wang, Haitao; Li, Dong; Yang, Xujun; An, Xinli; Zheng, Xiaowei; Tian, Yun; Zheng, Wei; Zheng, Tianling

    2014-01-01

    Phaeocystis globosa blooms have frequently occurred along coastal waters and exerted serious impacts on ecological environments by releasing toxic hemolytic substances, forming nuisance foam, and causing oxygen depletion. An actinomycete strain RPS with high algicidal activity against P. globosa was isolated and identified as Streptomyces alboflavus, based on morphology, physiological and biochemical characteristics, and 16S rDNA sequence analysis. RPS lysed 95% of P. globosa within 48 h by releasing an extracellular active substance into the growth medium. The activity of RPS supernatant was sensitive to temperature at and above 50 °C and insensitive to pH from 3 to 11. The molecular weight of the active substance was between 100 Da and 1000 Da, and approximately 90% of it was extracted by ethyl acetate. It was presumed that the active component efficiently inhibited the movement of P. globosa, caused the flagella to fall off the algae, and finally lysed the algal cells. RPS showed a wide target range against harmful algae. S. alboflavus RPS with high algicidal activity and such novel features of temperature and pH sensitivity, low molecular weight, algicidal process, and target range possesses great potential in the biological control of P. globosa blooms. PMID:24675867

  7. Preparation of a new-style composite containing a key bioflocculant produced by Pseudomonas aeruginosa ZJU1 and its flocculating effect on harmful algal blooms.

    PubMed

    Sun, Peng-Fei; Lin, Hui; Wang, Guan; Lu, Li-Ling; Zhao, Yu-Hua

    2015-03-01

    A novel composite consisting of clay, bioflocculant, and inorganic flocculant was designed, and its flocculating effect on harmful algal blooms (HABs) was studied in this study. The extracellular polymeric substances (EPS), produced with a yield of 3.58±0.11 g/L by a newly isolated Pseudomonas aeruginosa ZJU1, was indicated to be a key component in the composite. The components and functional groups of the EPS were analyzed, and it showed that polysaccharides, proteins, and nucleic acids are the main components; polar functional groups in the EPS are responsible for its flocculating activity. The novel composite was optimized by the response surface methodology and after optimization, the optical components and contents of the composite were Kaolin 2.38 g/L, CaCl2 0.28 g/L, KAl(SO4)2 0.09 g/L, and EPS 1.75 mg/L. The flocculating rates of the composite were tested, and it could rapidly reach 100±0.13% within 2 min when OD680 of Microcystis aeruginosa was 0.1; it could reach 100±0.08% within 5 min for OD680 of M. aeruginosa in HABs up to 1.0. These results suggest that the novel composite will be a highly efficient material for the treatment of HABs caused by M. aeruginosa. PMID:25463236

  8. Effects of simetryne on growth of various freshwater algal taxa.

    PubMed

    Kasai, F; Takamura, N; Hatakeyama, S

    1993-01-01

    The sensitivity of 56 algal strains, representing 7 taxonomic groups to the triazine herbicide, simetryne, was examined using EC50 values for growth. There was a wide range of values from 6.5 to 1500 microg litre(-1). The Volvocales (Chlorophyceae, Chlorophyta) and Cyanophyceae (Cyanophyta) as a whole were the most sensitive, whereas the Desmidiales (Charophyceae, Chlorophyta) and Bacillariophyceae (Chromophyta) were the most tolerant, although sensitivity differed among strains of a single species. Sensitive and tolerant species were both isolated from samples collected at the same site. The results suggest that changes in species composition and relative abundance will occur when herbicides are applied in natural habitats. PMID:15091916

  9. Seasonality in the distribution of dinoflagellates with special reference to harmful algal species in tropical coastal environment, Bay of Bengal.

    PubMed

    Sahu, Gouri; Mohanty, A K; Samantara, M K; Satpathy, K K

    2014-10-01

    A study was carried out in the coastal waters of Kalpakkam, southeast coast of India, to find out the seasonal variation in dinoflagellate community structure. Samples were collected for a period of 4 years during 2006-2010. During the study 69 species of dinoflagellates were encountered among which Ceratium furca and Prorocentrum micans were most common during all the seasons. Genus Ceratium was found to be the most diverse one with 23 species which was followed by genus Protoperidinium with 16 species. Of 69 species, 27 species were considered as dominant based on their abundance during pre-monsoon (PRM), monsoon (MON) and post-monsoon (POM) periods. Relatively high density and diversity of dinoflagellates were encountered during the PRM period as compared to the MON and POM periods. Abundance pattern of dinoflagellates for three seasons showed the following trend: PRM > POM > MON. Salinity showed a positive correlation with dinoflagellate community showing its importance in dinoflagellate growth and sustenance. Ammonia and phosphate developed negative correlation with dinoflagellate density indicating the utilization of these nutrients by the dinoflagellate community. The presence of three dinoflagellate associations, broadly representing the three seasons experienced at this location, was evident from the cluster analysis. The study revealed presence of 19 relatively abundant toxic/red tide forming dinoflagellate species in the coastal waters of Kalpakkam. PMID:25012144

  10. Stressor-Response Models Relating Nutrient Enrichment to Algal Communities in Pacific Northwest Streams and Rivers

    NASA Astrophysics Data System (ADS)

    Sobota, D. J.; Hubler, S.; Paul, M. J.; Labiosa, R.

    2015-12-01

    Excessive algal growth in streams and rivers from nutrient enrichment can cause costly human health and environmental problems. As part of the US Environmental Protection Agency's Nutrient Scientific Technical Exchange Partnership and Support (N-STEPS) program, we have been developing stressor-response (S-R) models relating nutrients to attached algal (periphyton) communities to help prioritize monitoring for water quality impairments in Oregon (Pacific Northwest, USA) streams and rivers. Existing data from the state and neighboring states were compiled and standardized from the Oregon Department of Environmental Quality, US Environmental Protection Agency, and the US Geological Survey. To develop S-R models, algal community and biomass metrics were compared with nitrogen (N) and phosphorus (P) concentration data, including total, dissolved, and inorganic forms of these nutrients. In total, 928 paired algal-nutrient samples were compiled from the 8 Level-III Ecoregions occurring in Oregon. Relationships between algal biomass metrics and nutrient concentrations were weak, with only ash-free dry mass and standing stock of chlorophyll a showing slight positive relationships across gradients of total N and soluble reactive P concentrations, respectively. In contrast, metrics describing algal community composition, including percent diatoms and abundance of nutrient-sensitive species, showed very strong nonlinear relationships with total N or P concentrations. This suggests that data describing algal community composition can help identify specific nutrient stressors across environmentally-diverse streams and rivers in the Pacific Northwest. Future analyses will examine if nutrient-algal S-R models vary across different hydrological, physiographical, and ecological settings in the region.

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

    PubMed

    Villacorte, L O; Ekowati, Y; Neu, T R; Kleijn, J M; Winters, H; Amy, G; Schippers, J C; Kennedy, M D

    2015-04-15

    Algal blooms can seriously affect the operation of water treatment processes including low pressure (micro- and ultra-filtration) and high pressure (nanofiltration and reverse osmosis) membranes mainly due to accumulation of algal-derived organic matter (AOM). In this study, the different components of AOM extracted from three common species of bloom-forming algae (Alexandrium tamarense, Chaetoceros affinis and Microcystis sp.) were characterised employing various analytical techniques, such as liquid chromatography - organic carbon detection, fluorescence spectroscopy, fourier transform infrared spectroscopy, alcian blue staining and lectin staining coupled with laser scanning microscopy to indentify its composition and force measurement using atomic force microscopy to measure its stickiness. Batch culture monitoring of the three algal species illustrated varying characteristics in terms of growth pattern, cell concentration and AOM release. The AOM produced by the three algal species comprised mainly biopolymers (e.g., polysaccharides and proteins) but some refractory compounds (e.g., humic-like substances) and other low molecular weight acid and neutral compounds were also found. Biopolymers containing fucose and sulphated functional groups were found in all AOM samples while the presence of other functional groups varied between different species. A large majority (>80%) of the acidic polysaccharide components (in terms of transparent exopolymer particles) were found in the colloidal size range (<0.4 μm). The relative stickiness of AOM substantially varied between algal species and that the cohesion between AOM-coated surfaces was much stronger than the adhesion of AOM on AOM-free surfaces. Overall, the composition as well as the physico-chemical characteristics (e.g., stickiness) of AOM will likely dictate the severity of fouling in membrane systems during algal blooms. PMID:25682049

  12. Isolation of an algicide from a marine bacterium and its effects against the toxic dinoflagellate Alexandrium catenella and other harmful algal bloom species.

    PubMed

    Kim, Yun Sook; Son, Hong-Joo; Jeong, Seong-Yun

    2015-08-01

    The aim of this study was to isolate and identify bacteria demonstrating an algicidal effect against Alexandrium catenella and to determine the activity and range of any algicide discovered. The morphological and biochemical attributes of an algicidal bacterium, isolate YS-3, and analysis of its 16S rRNA gene sequence revealed it to be a member of the genus Brachybacterium. This organism, designated Brachybacterium sp. YS-3, showed the greatest effect against A. catenella cells of all bacteria isolated, and is assumed to produce secondary metabolites. When 10% solutions of culture filtrates from this strain were applied to A. catenella cultures, over 90% of cells were killed within 9 h. Bioassay-guided isolation of the algicide involved led to the purification and identification of an active compound. Based on physicochemical and spectroscopic data, including nuclear magnetic resonance and mass analyses, this compound was identified as 1-acetyl-β-carboline. This algicide showed significant activity against A. catenella and a wide range of harmful algal bloom (HAB)-forming species. Taken together, our results suggest that Brachybacterium sp. YS-3 and its algicide represent promising candidates for use in HAB control. PMID:26224453

  13. Effects of solar ultraviolet radiation on tropical algal communities

    SciTech Connect

    Santas, R.

    1989-01-01

    This study assessed some of the effects of solar ultraviolet (UV) radiation ion coral reef algal assemblages. The first part of the investigation was carried out under controlled laboratory conditions in the coral reef microcosm at the National Museum of Natural History in Washington, D.C., while a field counterpart was completed at the Smithsonian Institution's marine station on Grand Turk, Turks and Caicos Islands, in the eastern Caribbean. The study attempted to separate the effects of UV-A from those of UV-B. In the laboratory, algal turf assemblages exposed to simulated solar UV radiation produced 55.1% less biomass than assemblages that were not exposed to UV. Assemblages not exposed to UV were dominated by Ectocarpus rhodochondroides, whereas in the assemblage developing under high UV radiation, Enteromorpha prolifera and eventually Schizothrix calcicola dominated. Lower UV-B irradiances caused a proportional reduction in biomass production and had less pronounced effects on species composition. UV-A did not have any significant effects on either algal turf productivity or community structure. In the field, assemblages exposed to naturally occurring solar UV supported a biomass 40% lower than that of assemblages protected from UV-B exposure. Once again, UV-A did not inhibit algal turf productivity.

  14. Two coexisting tank bromeliads host distinct algal communities on a tropical inselberg.

    PubMed

    Carrias, J-F; Céréghino, R; Brouard, O; Pélozuelo, L; Dejean, A; Couté, A; Corbara, B; Leroy, C

    2014-09-01

    The tank bromeliads Aechmea aquilega (Salisb.) and Catopsis berteroniana (Schultes f.) coexist on a sun-exposed Neotropical inselberg in French Guiana, where they permit conspicuous freshwater pools to form that differ in size, complexity and detritus content. We sampled the algal communities (both eukaryotic and cyanobacterial taxa, including colourless forms) inhabiting either A. aquilega (n = 31) or C. berteroniana (n = 30) and examined differences in community composition and biomass patterns in relation to several biotic and abiotic variables. Chlorella sp. and Bumilleriopsis sp. were the most common taxa and dominated the algal biomass in A. aquilega and C. berteroniana, respectively. Using a redundancy analysis, we found that water volume, habitat complexity and the density of phagotrophic protozoa and collector-gatherer invertebrates were the main factors explaining the distribution of the algal taxa among the samples. Hierarchical clustering procedures based on abundance and presence/absence data clearly segregated the samples according to bromeliad species, revealing that the algal communities in the smaller bromeliad species were not a subset of the communities found in the larger bromeliad species. We conclude that, even though two coexisting tank bromeliad populations create adjacent aquatic habitats, each population hosts a distinct algal community. Hence, bromeliad diversity is thought to promote the local diversity of freshwater algae in the Neotropics. PMID:24400863

  15. Efficacy of algal metrics for assessing nutrient and organic enrichment in flowing waters

    USGS Publications Warehouse

    Porter, S.D.; Mueller, D.K.; Spahr, N.E.; Munn, M.D.; Dubrovsky, N.M.

    2008-01-01

    4. Although algal species tolerance to nutrient and organic enrichment is well documented, additional taxonomic and autecological research on sensitive, endemic algal species would further enhance water-quality assessments.

  16. Chemical composition of various Ephedra species.

    PubMed

    Ibragic, Saida; Sofić, Emin

    2015-01-01

    The medicinal significance of Ephedra is based on the sympathomimetic properties of ephedrine (E) alkaloids. Pharmacological effects depend on the phytocomposition of individual Ephedra species. The aim of this study was to measure the total alkaloids content (TAC), total phenolics content (TPC), and total flavonoids content (TFC) and determine their relationship in dry herb of Ephedra major, Ephedra distachya subsp. helvetica, Ephedra monosperma, Ephedra fragilis, Ephedra foeminea, Ephedra alata, Ephedra altissima and Ephedra foliata. Nowadays, medicinal use of Ephedrae herba is limited, but the abuse of its psychostimulants is rising. In this study, TAC, TPC and TFC were determined using spectrophotometric methods. For the first time, ultra-performance liquid chromatography with ultraviolet detection (UPLC-UV) was used for separation and quantification of E-type alkaloids of various Ephedra species. The highest TPC and TFC were found in E. alata (53.3 ± 0.1 mg Gallic acid equivalents/g dry weight, 2.8 mg quercetin equivalents/g dry weight, respectively). The total content of E and pseudoephedrine determined by UPLC-UV varied between 20.8 mg/g dry weight (E. distachya subsp. helvetica) and 34.7 mg/g dry weight (E. monosperma). The variable content and ratio between secondary metabolites determined in different Ephedra species reflects their metabolic activities. Utilization of UPLC-UV unveiled that this technique is sensitive, selective, and useful for separation and quantification of different alkaloids in complex biological matrixes. The limit of detection was 5 ng. Application of UPLC-UV can be recommended in quick analyses of E-type alkaloids in forensic medicine and quality control of pharmaceutical preparations. PMID:26295290

  17. Chemical composition of various Ephedra species

    PubMed Central

    Ibragic, Saida; Sofić, Emin

    2015-01-01

    The medicinal significance of Ephedra is based on the sympathomimetic properties of ephedrine (E) alkaloids. Pharmacological effects depend on the phytocomposition of individual Ephedra species. The aim of this study was to measure the total alkaloids content (TAC), total phenolics content (TPC), and total flavonoids content (TFC) and determine their relationship in dry herb of Ephedra major, Ephedra distachya subsp. helvetica, Ephedra monosperma, Ephedra fragilis, Ephedra foeminea, Ephedra alata, Ephedra altissima and Ephedra foliata. Nowadays, medicinal use of Ephedrae herba is limited, but the abuse of its psychostimulants is rising. In this study, TAC, TPC and TFC were determined using spectrophotometric methods. For the first time, ultra-performance liquid chromatography with ultraviolet detection (UPLC-UV) was used for separation and quantification of E-type alkaloids of various Ephedra species. The highest TPC and TFC were found in E. alata (53.3 ± 0.1 mg Gallic acid equivalents/g dry weight, 2.8 mg quercetin equivalents/g dry weight, respectively). The total content of E and pseudoephedrine determined by UPLC-UV varied between 20.8 mg/g dry weight (E. distachya subsp. helvetica) and 34.7 mg/g dry weight (E. monosperma). The variable content and ratio between secondary metabolites determined in different Ephedra species reflects their metabolic activities. Utilization of UPLC-UV unveiled that this technique is sensitive, selective, and useful for separation and quantification of different alkaloids in complex biological matrixes. The limit of detection was 5 ng. Application of UPLC-UV can be recommended in quick analyses of E-type alkaloids in forensic medicine and quality control of pharmaceutical preparations. PMID:26295290

  18. Plant species composition and biofuel yields of conservation grasslands.

    PubMed

    Adler, Paul R; Sanderson, Matt A; Weimer, Paul J; Vogel, Kenneth P

    2009-12-01

    Marginal croplands, such as those in the Conservation Reserve Program (CRP), have been suggested as a source of biomass for biofuel production. However, little is known about the composition of plant species on these conservation grasslands or their potential for ethanol production. Our objective was to assess the potential of CRP and other conservation grasslands for biofuel production, describing the relationships of plant species richness and tall native C4 prairie grass abundance with plant chemical composition and the resulting potential ethanol yield. We determined plant species composition and diversity at multiple scales with the modified Whittaker plot technique, aboveground biomass, plant chemical composition, and potential ethanol yield at 34 sites across the major ecological regions of the northeastern USA. Conservation grasslands with higher numbers of plant species had lower biomass yields and a lower ethanol yield per unit biomass compared with sites with fewer species. Thus, biofuel yield per unit land area decreased by 77% as plant species richness increased from 3 to 12.8 species per m2. We found that, as tall native C4 prairie grass abundance increased from 1.7% to 81.6%, the number of plant species decreased and aboveground biomass per unit land area and ethanol yield per unit biomass increased resulting in a 500% increased biofuel yield per unit land area. Plant species richness and composition are key determinants of biomass and ethanol yields from conservation grasslands and have implications for low-input high-diversity systems. Designing systems to include a large proportion of species with undesirable fermentation characteristics could reduce ethanol yields. PMID:20014588

  19. Eukaryotic algal phytochromes span the visible spectrum.

    PubMed

    Rockwell, Nathan C; Duanmu, Deqiang; Martin, Shelley S; Bachy, Charles; Price, Dana C; Bhattacharya, Debashish; Worden, Alexandra Z; Lagarias, J Clark

    2014-03-11

    Plant phytochromes are photoswitchable red/far-red photoreceptors that allow competition with neighboring plants for photosynthetically active red light. In aquatic environments, red and far-red light are rapidly attenuated with depth; therefore, photosynthetic species must use shorter wavelengths of light. Nevertheless, phytochrome-related proteins are found in recently sequenced genomes of many eukaryotic algae from aquatic environments. We examined the photosensory properties of seven phytochromes from diverse algae: four prasinophyte (green algal) species, the heterokont (brown algal) Ectocarpus siliculosus, and two glaucophyte species. We demonstrate that algal phytochromes are not limited to red and far-red responses. Instead, different algal phytochromes can sense orange, green, and even blue light. Characterization of these previously undescribed photosensors using CD spectroscopy supports a structurally heterogeneous chromophore in the far-red-absorbing photostate. Our study thus demonstrates that extensive spectral tuning of phytochromes has evolved in phylogenetically distinct lineages of aquatic photosynthetic eukaryotes. PMID:24567382

  20. Estimating Forest Species Composition Using a Multi-Sensor Approach

    NASA Astrophysics Data System (ADS)

    Wolter, P. T.

    2009-12-01

    The magnitude, duration, and frequency of forest disturbance caused by the spruce budworm and forest tent caterpillar has increased over the last century due to a shift in forest species composition linked to historical fire suppression, forest management, and pesticide application that has fostered the increase in dominance of host tree species. Modeling approaches are currently being used to understand and forecast potential management effects in changing insect disturbance trends. However, detailed forest composition data needed for these efforts is often lacking. Here, we used partial least squares (PLS) regression to integrate satellite sensor data from Landsat, Radarsat-1, and PALSAR, as well as pixel-wise forest structure information derived from SPOT-5 sensor data (Wolter et al. 2009), to estimate species-level forest composition of 12 species required for modeling efforts. C-band Radarsat-1 data and L-band PALSAR data were frequently among the strongest predictors of forest composition. Pixel-level forest structure data were more important for estimating conifer rather than hardwood forest composition. The coefficients of determination for species relative basal area (RBA) ranged from 0.57 (white cedar) to 0.94 (maple) with RMSE of 8.88 to 6.44 % RBA, respectively. Receiver operating characteristic (ROC) curves were used to determine the effective lower limits of usefulness of species RBA estimates which ranged from 5.94 % (jack pine) to 39.41 % (black ash). These estimates were then used to produce a dominant forest species map for the study region with an overall accuracy of 78 %. Most notably, this approach facilitated discrimination of aspen from birch as well as spruce and fir from other conifer species which is crucial for the study of forest tent caterpillar and spruce budworm dynamics, respectively, in the Upper Midwest. Thus, use of PLS regression as a data fusion strategy has proven to be an effective tool for regional characterization of forest

  1. Algal Flocculation with Synthetic Organic Polyelectrolytes

    PubMed Central

    Tenney, Mark W.; Echelberger, Wayne F.; Schuessler, Ronald G.; Pavoni, Joseph L.

    1969-01-01

    The feasibility of removing algae from water and wastewater by chemical flocculation techniques was investigated. Mixed cultures of algae were obtained from both continuous- and batch-fed laboratory reactors. Representative cationic, anionic, and nonionic synthetic organic polyelectrolytes were used as flocculants. Under the experimental conditions, chemically induced algal flocculation occurred with the addition of cationic polyelectrolyte, but not with anionic or nonionic polymers, although attachment of all polyelectrolyte species to the algal surface is shown. The mechanism of chemically induced algal flocculation is interpreted in terms of bridging phenomena between the discrete algal cells and the linearly extended polymer chains, forming a three-dimensional matrix that is capable of subsiding under quiescent conditions. The degree of flocculation is shown to be a direct function of the extent of polymer coverage of the active sites on the algal surface, although to induce flocculation by this method requires that the algal surface charge must concurrently be reduced to a level at which the extended polymers can bridge the minimal distance of separation imposed by electrostatic repulsion. The influence of pH, algal concentration, and algal growth phase on the requisite cationic flocculant dose is also reported. PMID:5370666

  2. CHARACTERIZATION OF 17 NEW MICROSATELLITE MARKERS FOR THE DINOFLAGELLATE ALEXANDRIUM FUNDYENSE (DINOPHYCEAE), A HARMFUL ALGAL BLOOM SPECIES

    PubMed Central

    Sehein, Taylor; Richlen, Mindy L.; Nagai, Satoshi; Yasuike, Motoshige; Nakamura, Yoji; Anderson, Donald M.

    2016-01-01

    Alexandrium fundyense is the toxic marine dinoflagellate responsible for “red tide” events in temperate and sub-arctic waters worldwide. In the Gulf of Maine (GOM) and Bay of Fundy in the Northwest Atlantic, blooms of A. fundyense recur annually, and are associated with major health and ecosystem impacts. In this region, microsatellite markers have been used to investigate genetic structure and gene flow; however, the loci currently available for this species were isolated from populations from Japan and the North Sea, and only a subset are suitable for the analysis of A. fundyense populations in the Northwest Atlantic. To facilitate future studies of A. fundyense blooms, both in this region and globally, we isolated and characterized 17 polymorphic microsatellite loci from 31 isolates collected from the GOM and from the Nauset Marsh System, an estuary on Cape Cod, MA, USA. These loci yielded between two and 15 alleles per locus, with an average of 7.1. Gene diversities ranged from 0.297 to 0.952. We then analyzed these same 31 isolates using previously published markers for comparison. We determined the new markers are sufficiently variable and better suited for the investigation of genetic structure, bloom dynamics, and diversity in the Northwest Atlantic. PMID:27274617

  3. Aerial extent, composition, bio-optics and biogeochemistry of a massive under-ice algal bloom in the Arctic

    NASA Astrophysics Data System (ADS)

    Balch, W. M.; Bowler, B. C.; Lubelczyk, L. C.; Stevens, M. W.

    2014-07-01

    It has been long thought that coccolithophores are a minor component of the phytoplankton assemblage in Arctic waters, with diatoms typically being more dominant. Little is known about how the phytoplankton communities will change, however, as the Arctic warms. We participated in the 2011 Impacts of Climate on EcoSystems and Chemistry of the Arctic Pacific Environment (ICESCAPE) cruise to the western Arctic, performing a combination of discrete measurements (microscopy, calcification, particulate inorganic carbon (PIC), particulate organic carbon (POC), biogenic silica (BSi)) plus continuous surface bio-optical measurements (absorption, scattering, backscattering and acid-labile backscattering; the latter specific for coccolithophores). Here, we report bio-optical and coccolithophore observations from the massive under-ice algal bloom originally described in Arrigo et al. (2012). The most intense portions of the bloom were centered in cold Winter Water and there was evidence for nitrate drawdown in the top 10-20 m with strong penetration of silicate rich water into the surface waters. Surface chlorophyll a and particulate absorption at 440 nm approached 30 μg L-1 and 1.0 m-1, respectively. Particulate absorption of detritus (ap at 412 nm) was highly correlated to ap at 440 nm associated with chlorophyll a and slopes of the absorption spectrum showed that both dissolved and particulate absorption at 412 nm exceeded that at 440 nm, with slopes, Sg, of 0.01 nm-1. Colored dissolved organic matter fluorescence (FDOM) was high in the bloom but the relative fluorescence yields were low, characteristic of phytoplankton-produced FDOM (as opposed to terrestrially-produced FDOM). Coccolithophore backscattering was elevated in the under-ice bloom, but it only accounted for 10% of the total particle backscattering, relatively low compared to typical subpolar waters further to the south. Total particle scattering was significantly elevated in the under-ice bloom (values of

  4. The spatial arrangement of reefs alters the ecological patterns of fauna between interspersed algal habitats

    NASA Astrophysics Data System (ADS)

    Tuya, F.; Wernberg, T.; Thomsen, M. S.

    2008-07-01

    Reef landscapes dominated by canopy-forming species are often irregular mosaics of habitats, with important influences on associated fauna. This study tested if differences in the ecological patterns of mobile fauna inhabiting interspersed (morphologically distinct) algal habitats were altered by the spatial arrangement of reefs of varying proximity to the shoreline. Specifically, prosobranch gastropods were used as models to test that: (1) there were differences in the ecological patterns (species composition and abundances) between three algal habitats (the kelp Ecklonia radiata, fucalean macroalgae, and erect red algae); (2) the magnitude of these differences depended on the position of reef lines ('in-shore' vs. 'off-shore'); and (3) these effects were regionally consistent across a ˜4° latitudinal gradient (˜600 km of coastline) in Western Australia. The ecological patterns of algal-associated gastropods responded strongly to the presence of algal habitats with different physical structure at small spatial scales. Importantly, differences in assemblage structure (e.g. differences in total abundances) between habitats across the latitudinal gradient were especially accentuated on the in-shore reefs compared with the off-shore reefs, where a general amelioration of differences between habitats was observed, probably associated with a more widespread effect of stronger wave forces across habitats. Overall, red algae supported higher total abundances and species richness (per algal weight) compared to the other algal habitats, particularly on in-shore reefs. Patterns for individual species were considerably location-dependent, reflecting the natural variability of species across geographical gradients. In contrast, patterns at the assemblage-level were consistent, providing evidence for the existence of general rules underlying the assemblage-level organization of mobile invertebrates on subtidal reefs across this geographical gradient.

  5. Influence of light, nutrients, and temperature on the toxicity of atrazine to the algal species Raphidocelis subcapitata: Implications for the risk assessment of herbicides.

    PubMed

    Baxter, Leilan; Brain, Richard A; Lissemore, Linda; Solomon, Keith R; Hanson, Mark L; Prosser, Ryan S

    2016-10-01

    The acute toxicity of herbicides to algae is commonly assessed under conditions (e.g., light intensity, water temperature, concentration of nutrients, pH) prescribed by standard test protocols. However, the observed toxicity may vary with changes in one or more of these parameters. This study examined variation in toxicity of the herbicide atrazine to a representative green algal species Raphidocelis subcapitata (formerly Pseudokirchneriella subcapitata) with changes in light intensity, water temperature, concentrations of nutrients or combinations of these three parameters. Conditions were chosen that could be representative of the intensive corn growing Midwestern region of the United States of America where atrazine is used extensively. Varying light intensity (4-58µmol/m(2)s) resulted in no observable trend in 96-h EC50 values for growth rate. EC50 values for PSII yield generally increased with decreasing light intensity but not significantly in all cases. The 96-h EC50 values for growth rate decreased with decreases in temperature (20-5°C) from standard conditions (25°C), but EC50 values for PSII yield at lower temperatures were not significantly different from standard conditions. Finally, there was no clear trend in 96-h EC50 values for both endpoints with increases in nitrogen (4.1-20mg/L) and phosphorus (0.24-1.2mg/L). The 96-h EC50 values for both endpoints under combinations of conditions mimicking aquatic systems in the Midwestern U.S. were not significantly different from EC50 values generated under standard test conditions. This combination of decreased light intensity and temperature and increased nutrients relative to standard conditions does not appear to significantly affect the observed toxicity of atrazine to R. subcapitata. For atrazine specifically, and for perhaps other herbicides, this means current laboratory protocols are useful for extrapolating to effects on algae under realistic environmental conditions. PMID:27340884

  6. Conservation tillage affects species composition but not species diversity: a comparative study in Northern Italy.

    PubMed

    Boscutti, Francesco; Sigura, Maurizia; Gambon, Nadia; Lagazio, Corrado; Krüsi, Bertil O; Bonfanti, Pierluigi

    2015-02-01

    Conservation tillage (CT) is widely considered to be a practice aimed at preserving several ecosystem functions. In the literature, however, there seems to be no clear pattern with regard to its benefits on species diversity and species composition. In Northern Italy, we compared species composition and diversity of both vascular plants and Carabids under two contrasting tillage systems, i.e., CT and conventional tillage, respectively. We hypothesized a significant positive impact of CT on both species diversity and composition. We also considered the potential influence of crop type. The tillage systems were studied under open field conditions with three types of annual crops (i.e., maize, soybean, and winter cereals), using a split-plot design on pairs of adjacent fields. Linear mixed models were applied to test tillage system, crop, and interaction effects on diversity indices. Plant and Carabids communities were analyzed by multivariate methods (CCA). On the whole, 136 plant and 51 carabid taxa were recorded. The two tillage systems studied did not differ in floristic or carabid diversity. Species composition, by contrast, proved to be characteristic for each combination of tillage system and crop type. In particular, CT fields were characterized by nutrient demanding weeds and the associated Carabids. The differences were especially pronounced in fields with winter cereals. The same was true for the flora and Carabids along the field boundaries. For studying the effects of CT practices on the sustainability of agro-ecosystems, therefore, the focus should be on species composition rather than on diversity measures. PMID:25392019

  7. Conservation Tillage Affects Species Composition But Not Species Diversity: A Comparative Study in Northern Italy

    NASA Astrophysics Data System (ADS)

    Boscutti, Francesco; Sigura, Maurizia; Gambon, Nadia; Lagazio, Corrado; Krüsi, Bertil O.; Bonfanti, Pierluigi

    2015-02-01

    Conservation tillage (CT) is widely considered to be a practice aimed at preserving several ecosystem functions. In the literature, however, there seems to be no clear pattern with regard to its benefits on species diversity and species composition. In Northern Italy, we compared species composition and diversity of both vascular plants and Carabids under two contrasting tillage systems, i.e., CT and conventional tillage, respectively. We hypothesized a significant positive impact of CT on both species diversity and composition. We also considered the potential influence of crop type. The tillage systems were studied under open field conditions with three types of annual crops (i.e., maize, soybean, and winter cereals), using a split-plot design on pairs of adjacent fields. Linear mixed models were applied to test tillage system, crop, and interaction effects on diversity indices. Plant and Carabids communities were analyzed by multivariate methods (CCA). On the whole, 136 plant and 51 carabid taxa were recorded. The two tillage systems studied did not differ in floristic or carabid diversity. Species composition, by contrast, proved to be characteristic for each combination of tillage system and crop type. In particular, CT fields were characterized by nutrient demanding weeds and the associated Carabids. The differences were especially pronounced in fields with winter cereals. The same was true for the flora and Carabids along the field boundaries. For studying the effects of CT practices on the sustainability of agro-ecosystems, therefore, the focus should be on species composition rather than on diversity measures.

  8. Algal exudates and stream organic matter influence the structure and function of denitrifying bacterial communities.

    PubMed

    Kalscheur, Kathryn N; Rojas, Miguel; Peterson, Christopher G; Kelly, John J; Gray, Kimberly A

    2012-11-01

    Within aquatic ecosystems, periphytic biofilms can be hot spots of denitrification, and previous work has suggested that algal taxa within periphyton can influence the species composition and activity of resident denitrifying bacteria. This study tested the hypothesis that algal species composition within biofilms influences the structure and function of associated denitrifying bacterial communities through the composition of organic exudates. A mixed population of bacteria was incubated with organic carbon isolated from one of seven algal species or from one of two streams that differed in anthropogenic inputs. Pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) revealed differences in the organic composition of algal exudates and stream waters, which, in turn, selected for distinct bacterial communities. Organic carbon source had a significant effect on potential denitrification rates (DNP) of the communities, with organics isolated from a stream with high anthropogenic inputs resulting in a bacterial community with the highest DNP. There was no correlation between DNP and numbers of denitrifiers (based on nirS copy numbers), but there was a strong relationship between the species composition of denitrifier communities (as indicated by tag pyrosequencing of nosZ genes) and DNP. Specifically, the relative abundance of Pseudomonas stutzeri-like nosZ sequences across treatments correlated significantly with DNP, and bacterial communities incubated with organic carbon from the stream with high anthropogenic inputs had the highest relative abundance of P. stutzeri-like nosZ sequences. These results demonstrate a significant relationship between bacterial community composition and function and provide evidence of the potential impacts of anthropogenic inputs on the structure and function of stream microbial communities. PMID:22828897

  9. Linking limitation to species composition: importance of inter- and intra-specific variation in grazing resistance.

    PubMed

    Darcy-Hall, Tara L; Hall, Spencer R

    2008-04-01

    Short-term responses of producers highlight that key nutrients (e.g., N, P)-or combinations of these nutrients-limit primary production in aquatic and terrestrial ecosystems. These discoveries continue to provide highly valuable insights, but it remains important to ask whether nutrients always predominantly limit producers despite wide variation in nutrient supply and herbivory among systems. After all, predictions from simple food chain models (derived here) readily predict that limitation by grazers can exceed that by nutrients, given sufficient enrichment. However, shifts in composition of producers and/or increasing dominance of invulnerable stages of a producer can, in theory, reduce grazer limitation and retain primacy of nutrient limitation along nutrient supply gradients. We observed both mechanisms (inter- and intra-species variation in vulnerability to herbivory) working in a two-part mesocosm experiment. We incubated diverse benthic algal assemblages for several months either in the presence or absence of benthic macro-grazers in mesocosms that spread a broad range of nutrient supply. We then conducted short-term assays of nutrient and grazer limitation on these communities. In the "historically grazed" assemblages, we found shifts from more edible, better competitors to more resistant producers over enrichment gradients (as anticipated by the food web model built with a tradeoff in resistance vs. competitive abilities). However, contrary to our expectations, "historically ungrazed" assemblages became dominated by producers with vulnerable juvenile forms but inedible adult forms (long filaments). Consequently, we observed higher resource limitation rather than grazer limitation over this nutrient supply gradient in both "historically grazed" (expected) and "historically ungrazed" (not initially expected). Thus, via multiple, general mechanisms involving resistance to grazing (changes in species composition or variation in stage-structured vulnerability

  10. Effects of temperature, salinity, and irradiance on the growth of harmful algal bloom species Phaeocystis globosa Scherffel (Prymnesiophyceae) isolated from the South China Sea

    NASA Astrophysics Data System (ADS)

    Xu, Ning; Huang, Bozhu; Hu, Zhangxi; Tang, Yingzhong; Duan, Shunshan; Zhang, Chengwu

    2016-06-01

    Blooms of Phaeocystis globosa have been frequently reported in Chinese coastal waters, causing serious damage to marine ecosystems. To better understand the ecological characteristics of P. globosa in Chinese coastal waters that facilitate its rapid expansion, the effects of temperature, salinity and irradiance on the growth of P. globosa from the South China Sea were examined in the laboratory. The saturating irradiance for the growth of P. globosa (I s) was 60 μmol/(m2•s), which was lower than those of other harmful algal species (70-114 μmol/(m2•s)). A moderate growth rate of 0.22/d was observed at 2 μmol/(m2•s) (the minimum irradiance in the experiment), and photo-inhibition did not occur at 230 μmol/(m2•s) (the maximum irradiance in the experiment). Exposed to 42 different combinations of temperatures (10-31°C) and salinities (10-40) under saturating irradiance, P. globosa exhibited its maximum specific growth rate of 0.80/d at the combinations of 24°C and 35, and 27°C and 40. The optimum growth rates (>0.80/d) were observed at temperatures ranging from 24 to 27°C and salinities from 35 to 40. While P. globosa was able to grow well at temperatures from 20°C to 31°C and salinities from 20 to 40, it could not grow at temperatures lower than 15°C or salinities lower than 15. Factorial analysis revealed that temperature and salinity has similar influences on the growth of this species. This strain of P. globosa not only prefers higher temperatures and higher salinity, but also possesses a flexible nutrient competing strategy, adapted to lower irradiance. Therefore, the P. globosa population from South China Sea should belong to a new ecotype. There is also a potentially high risk of blooms developing in this area throughout the year.

  11. Effects of Hypoxia on the Phylogenetic Composition and Species Distribution of Protists in a Subtropical Harbor.

    PubMed

    Rocke, Emma; Jing, Hongmei; Xia, Xiaomin; Liu, Hongbin

    2016-07-01

    Tolo Harbor, a subtropical semi-enclosed coastal water body, is surrounded by an expanding urban community, which contributes to large concentrations of nutrient runoff, leading to algal blooms and localized hypoxic episodes. Present knowledge of protist distributions in subtropical waters during hypoxic conditions is very limited. In this study, therefore, we combined parallel 454 pyrosequencing technology and denaturing gradient gel electrophoresis (DGGE) fingerprint analyses to reveal the protist community shifts before, during, and after a 2-week hypoxic episode during the summer of 2011. Hierarchical clustering for DGGE demonstrated similar grouping of hypoxic samples separately from oxic samples. Dissolved oxygen (DO) concentration and dissolved inorganic nitrogen:phosphate (DIN:PO4) concentrations significantly affected OTU distribution in 454 sequenced samples, and a shift toward a ciliate and marine alveolate clade II (MALV II) species composition occurred as waters shifted from oxic to hypoxic. These results suggest that protist community shifts toward heterotrophic and parasitic tendencies as well as decreased diversity and richness in response to hypoxic outbreaks. PMID:26979838

  12. Polyphenol composition and antioxidant capacity of Epilobium species.

    PubMed

    Hevesi Tóth, Barbara; Blazics, Balázs; Kéry, Agnes

    2009-01-15

    Epilobium species (Onagraceae) are commonly used herbal remedies in traditional, adjuvant therapy of benignus prostate hyperplasia (BPH), however the pharmacological and clinical standardization of commercially available Epilobii herba (willow-herb) remains difficult. Willow-herb products usually consist of mixtures from various species, with different phenoloid content, often only partially identified. The present study reports comprehensive LC-MS/MS investigation on the polyphenol composition of the most common Epilobium species, emphasizing the pharmaceutical importance of a uniform standardization protocol in case of their products. The antioxidant capacity of species was evaluated by a simple spectrophotometric method, using ABTS(+) (2,2'azinobis-(3-ethylbenzthiazoline-6-sulfonic acid)). High ratio of macrocyclic tannins, mainly oenothein B was identified in all Epilobium species examined. Flavonoid composition of Epilobium extracts showed several differences, especially comparing E. angustifolium to other species. Myricetin, quercetin, kaempferol and their various glycosides were dominant in samples, but their combination and ratio were distinctive in all cases. Epilobium extracts showed high radical-scavenger activity, comparable to that of well-known antioxidants, Trolox and ascorbic acid. Among species examined, extract of Epilobium parviflorum possessed the highest antioxidant capacity (EC(50)=1.71+/-0.05 microg/ml). PMID:19013046

  13. Effectiveness of mosquito traps in measuring species abundance and composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquito species abundance and composition estimates provided by trapping devices are commonly used to guide control efforts, but knowledge of trap biases is necessary for accurately interpreting results. We compared the Mosquito Magnet – Pro, the Mosquito Magnet – X and the CDC Miniature Light Trap...

  14. Plant species composition and biofuel yields of conservation grasslands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marginal croplands, such as those in the Conservation Reserve Program (CRP), have been suggested as a source of biomass for biofuel production. However, little is known about the composition of plant species on these conservation grasslands or their potential for ethanol production. Our objective w...

  15. Hydrogen Isotopic Ratios of Lacustrine Algal and Terrestrial Organic Matter as a Quantitative Proxy for the Reconstruction of Relative Humidity and Source Water Composition in Continental Settings

    NASA Astrophysics Data System (ADS)

    Cross, E.; Hollander, D.; Huang, Y.; Vanvleet, E.

    2004-12-01

    Sedimentary studies have indicated that hydrologic conditions in low latitude continental environments have varied significantly during the late Quaternary and throughout the mid to late Holocene in association with sea level variations and major climatic phenomena such as the migration and mean position of the ITCZ. However, a quantitative approach to understanding hydrologic variability (i.e. variations in source water composition and relative humidity) is needed to accurately reconstruct changes in moisture balance and paleoclimatic conditions. Lake Tulane, located in Central Florida, is a subtropical, groundwater-fed acidic lake with a high sedimentation rate and well-preserved organic matter. This study utilizes the hydrogen isotopic composition (dD) of organic molecules (fatty acids) associated with algal (C16) and terrestrial (C28) materials in a lacustrine system to provide a modern calibration that quantifies the isotopic behavior associated with 1) changes in the chemistry of source waters and 2) variability in relative humidity. Over an annual cycle, the dDC16 of modern algal material shows little variability reflecting a constant dD of lake water coincident with the groundwater-fed nature of the lake and relatively constant dD of precipitation. Terrestrial biomass shows a seasonal variability of ~15% with more enriched values occurring in winter when higher rates of evapotranspiration lead to isotopic enrichment. Seasonal variations in the magnitude of isotopic offset between the algae and terrestrial markers, (DdD(C16-C28) ), removes the variations in the source waters and, is quantitatively related to seasonal changes (~6%) in the relative humidity. Together, dDC16 and dDCc16-c28) from lacustrine archives can serve as proxies for the quantitative reconstruction of source water composition and relative humidity from sedimentary records preserved in continental settings. These newly developed dD molecular-hydrologic proxies are applied to the

  16. ALGAL RESPONSE TO NUTRIENT ENRICHMENT IN FORESTED OLIGOTROPHIC STREAM(1).

    PubMed

    Veraart, Annelies J; Romaní, Anna M; Tornés, Elisabet; Sabater, Sergi

    2008-06-01

    Nutrient input in streams alters the density and species composition of attached algal communities in open systems. However, in forested streams, the light reaching the streambed (rather than the local nutrient levels) may limit the growth of these communities. A nutrient-enrichment experiment in a forested oligotrophic stream was performed to test the hypothesis that nutrient addition has only minor effects on the community composition of attached algae and cyanobacteria under light limitation. Moderate nutrient addition consisted of increasing basal phosphorus (P) concentrations 3-fold and basal nitrogen (N) concentrations 2-fold. Two upstream control reaches were compared to a downstream reach before and after nutrient addition. Nutrients were added continuously to the downstream reach for 1 year. Algal biofilms growing on ceramic tiles were sampled and identified for more than a year before nutrient addition to 12 months after. Diatoms were the most abundant taxonomic group in the three stream reaches. Nutrient enrichment caused significant variations in the composition of the diatom community. While some taxa showed significant decreases (e.g., Achnanthes minutissima, Gomphonema angustum), increases for other taxa (such as Rhoicosphenia abbreviata and Amphora ovalis) were detected in the enriched reach (for taxonomic authors, see Table 2). Epiphytic and adnate taxa of large size were enhanced, particularly during periods of favorable growth conditions (spring). Nutrients also caused a change in the algal chl a, which increased from 0.5-5.8 to 2.1-10.7 μg chl · cm(-2) . Our results indicate that in oligotrophic forested streams, long-term nutrient addition has significant effects on the algal biomass and community composition, which are detectable despite the low light availability caused by the tree canopy. Low light availability moderates but does not detain the long-term tendency toward a nutrient-tolerant community. Furthermore, the effects

  17. Algal blooms and public health

    SciTech Connect

    Epstein, P.R. . Harvard Medical School)

    1993-06-01

    Alterations in coastal ecology are expanding the geographic extent, frequency, magnitude, and species complexity'' of algal blooms throughout the world, increasing the threat of fish and shellfish poisonings, anoxia in marine nurseries, and of cholera. The World Health Organization and members of the medical profession have described the potential health effects of global climate change. They warn of the consequences of increased ultraviolet-B (UV-B) rays and of warming: the possible damage to agriculture and nutrition, and the impact on habitats which may alter the distribution of vector-borne and water-based infectious diseases. Algal growth due to increased nitrogen (N) and phosphorus (P) and warming are already affecting marine microflora and aquatic plants; and there is now clear evidence that marine organisms are a reservoir for enteric pathogens. The pattern of cholera in the Western Hemisphere suggests that environmental changes have already begun to influence the epidemiology of this infectious disease. 106 refs.

  18. Spatial variability in plant species composition and peatland carbon exchange

    NASA Astrophysics Data System (ADS)

    Goud, E.; Moore, T. R.; Roulet, N. T.

    2015-12-01

    Plant species shifts in response to global change will have significant impacts on ecosystem carbon (C) exchange and storage arising from changes in hydrology. Spatial variation in peatland C fluxes have largely been attributed to the spatial distribution of microhabitats that arise from variation in surface topography and water table depth, but little is known about how plant species composition impacts peatland C cycling or how these impacts will be influenced by changing environmental conditions. We quantified the effect of species composition and environmental variables on carbon dioxide (CO2) and methane (CH4) fluxes over 2 years in a temperate peatland for four plant communities situated along a water table gradient from ombrotrophic bog to beaver pond. We hypothesized that (i) spatial heterogeneity in species composition would drive predictable spatial heterogeneity in C fluxes due to variation in plant traits and ecological tolerances, and (ii) increases in peat temperature would increase C fluxes. Species had different effects on C fluxes primarily due to differences in leaf traits. Differences in ecological tolerances among communities resulted in different rates of CO2 exchange in response to changes in water table depth. There was an overall reduction in ecosystem respiration (ER), gross primary productivity (GPP) and CH4 flux in response to colder peat temperatures in the second year, and the additive effects of a deeper water table in the bog margin and pond sites further reduced flux rates in these areas. These results demonstrate that different plant species can increase or decrease the flux of C into and out of peatlands based on differences in leaf traits and ecological tolerances, and that CO2 and CH4 fluxes are sensitive to changes in soil temperature, especially when coupled with changes in moisture availability.

  19. Algal Attributes: An Autecological Classification of Algal Taxa Collected by the National Water-Quality Assessment Program

    USGS Publications Warehouse

    Porter, Stephen D.

    2008-01-01

    Algae are excellent indicators of water-quality conditions, notably nutrient and organic enrichment, and also are indicators of major ion, dissolved oxygen, and pH concentrations and stream microhabitat conditions. The autecology, or physiological optima and tolerance, of algal species for various water-quality contaminants and conditions is relatively well understood for certain groups of freshwater algae, notably diatoms. However, applications of autecological information for water-quality assessments have been limited because of challenges associated with compiling autecological literature from disparate sources, tracking name changes for a large number of algal species, and creating an autecological data base from which algal-indicator metrics can be calculated. A comprehensive summary of algal autecological attributes for North American streams and rivers does not exist. This report describes a large, digital data file containing 28,182 records for 5,939 algal taxa, generally species or variety, collected by the U.S. Geological Survey?s National Water-Quality Assessment (NAWQA) Program. The data file includes 37 algal attributes classified by over 100 algal-indicator codes or metrics that can be calculated easily with readily available software. Algal attributes include qualitative classifications based on European and North American autecological literature, and semi-quantitative, weighted-average regression approaches for estimating optima using regional and national NAWQA data. Applications of algal metrics in water-quality assessments are discussed and national quartile distributions of metric scores are shown for selected indicator metrics.

  20. Nutritional compositions and bioactivities of Dacryodes species: a review.

    PubMed

    Tee, Lee Hong; Yang, Bao; Nagendra, Krishnamurthy Prasad; Ramanan, Ramakrishnan Nagasundara; Sun, Jian; Chan, Eng-Seng; Tey, Beng Ti; Azlan, Azrina; Ismail, Amin; Lau, Cheng Yuon; Jiang, Yueming

    2014-12-15

    Dacryodes species are evergreen, perennial trees with fleshy fruits and belong to the family Buseraseae. Many Dacryodes species are underutilized but are widely applied in traditional folk medicine to treat malaria, fever and skin diseases. The nutritional compositions, phytochemicals and biological activities of Dacryodes edulis, Dacryodes rostrata, Dacryodes buettneri, Dacryodes klaineana and Dacryodes hexandra are presented. The edible fruits of D. edulis are rich in lipids, proteins, vitamins, fatty acids and amino acids. Its extracts (leaf, fruit and resin) exhibit antioxidant, anti-microbial, anti-carcinogenic and other bioactivities. D. rostrata fruit has significant nutrient content, and is rich in proteins, lipids and minerals. These fruits are also highly rich in polyphenols, anthocyanins and antioxidant activities. This comprehensive review will assist the reader in understanding the nutritional benefits of Dacryodes species and in identifying current research needs. PMID:25038673

  1. Optimizing algal cultivation & productivity : an innovative, multidiscipline, and multiscale approach.

    SciTech Connect

    Murton, Jaclyn K.; Hanson, David T.; Turner, Tom; Powell, Amy Jo; James, Scott Carlton; Timlin, Jerilyn Ann; Scholle, Steven; August, Andrew; Dwyer, Brian P.; Ruffing, Anne; Jones, Howland D. T.; Ricken, James Bryce; Reichardt, Thomas A.

    2010-04-01

    Progress in algal biofuels has been limited by significant knowledge gaps in algal biology, particularly as they relate to scale-up. To address this we are investigating how culture composition dynamics (light as well as biotic and abiotic stressors) describe key biochemical indicators of algal health: growth rate, photosynthetic electron transport, and lipid production. Our approach combines traditional algal physiology with genomics, bioanalytical spectroscopy, chemical imaging, remote sensing, and computational modeling to provide an improved fundamental understanding of algal cell biology across multiple cultures scales. This work spans investigations from the single-cell level to ensemble measurements of algal cell cultures at the laboratory benchtop to large greenhouse scale (175 gal). We will discuss the advantages of this novel, multidisciplinary strategy and emphasize the importance of developing an integrated toolkit to provide sensitive, selective methods for detecting early fluctuations in algal health, productivity, and population diversity. Progress in several areas will be summarized including identification of spectroscopic signatures for algal culture composition, stress level, and lipid production enabled by non-invasive spectroscopic monitoring of the photosynthetic and photoprotective pigments at the single-cell and bulk-culture scales. Early experiments compare and contrast the well-studied green algae chlamydomonas with two potential production strains of microalgae, nannochloropsis and dunnaliella, under optimal and stressed conditions. This integrated approach has the potential for broad impact on algal biofuels and bioenergy and several of these opportunities will be discussed.

  2. Biotransformation of benzo[a]pyrene and other polycyclic aromatic hydrocarbons and heterocyclic analogs by several green algae and other algal species under gold and white light.

    PubMed

    Warshawsky, D; Cody, T; Radike, M; Reilman, R; Schumann, B; LaDow, K; Schneider, J

    1995-07-14

    This laboratory has shown that the metabolism of benzo[a]pyrene (BaP), a carcinogenic polycyclic aromatic hydrocarbon (PAH), by a freshwater green alga, Selenastrum capricornutum, under gold light proceeds through a dioxygenase pathway with subsequent conjugation and excretion. This study was undertaken to determine: (1) the effects of different light sources on the enzymatic or photochemical processes involved in the biotransformation of BaP over a dose range of 5-1200 mg/l; (2) the phototoxicity of carcinogenic PAHs and mutagenic quinones to a green alga; (3) the ability of other algal systems to metabolize BaP. Cultures were exposed to different doses of BaP for 2 days at 23 degrees C under gold, white or UV-A fluorescent light on a diurnal cycle of 16 h light, 8 h dark. Under gold light, metabolites of BaP produced by Selenastrum capricornutum were the dihydrodiols of which the 11,12-dihydrodiol was the major metabolite. Under white light, at low doses, the major metabolite was the 9,10-dihydrodiol. With increasing dose, the ratio of dihydrodiols to quinones decreased to less than two. With increasing light energy output, from gold to white to UV-A in the PAH absorbing region, BaP quinone production increased. Of other carcinogenic PAHs studied, only 7H-dibenz[c,g]carbazole was as phototoxic as BaP while 7,12-dimethylbenz[a]anthracene, dibenz[a,j]acridine and non-carcinogenic PAHs, anthracene and pyrene, were not phototoxic. The 3,6-quinone of BaP was found to be highly phototoxic while quinones that included menadione, danthron, phenanthrene-quinone and hydroquinone were not. The data suggest that the phototoxicity of BaP is due to photochemical production of quinones; the 3,6-quinone of BaP is phototoxic and is probably the result of the production of short lived cyclic reactive intermediates by the interaction of light with the quinone. Lastly, only the green algae, Selenastrum capricornutum, Scenedesmus acutus and Ankistrodesmus braunii almost completely

  3. Coccolithophore Dynamics In Alfonso Basin: Seasonal Variation And Species Composition

    NASA Astrophysics Data System (ADS)

    Cortés, M. Y.; Urcádiz-Cázares, F. J.; Silverberg, N.; Aguirre-Bahena, F.; Bollmann, J.

    2007-05-01

    The production of organic and inorganic carbon by coccolithophores is considered to play a significant role in the global carbon cycle. Therefore, detailed knowledge of their vertical flux is needed. Here we present a time-series record of coccolithophore standing stock and vertical coccolith flux from Alfonso Basin, southwest coast of the Gulf of California. This location is of particular interest as it is very sensitive to changes in environmental conditions and these may be preserved in laminated underlying sediments. Coccolithophore standing stock and assemblage composition were obtained from plankton samples taken at 3- month intervals during 2002-2003. Furthermore, coccolith flux and species composition were determined in samples from a time-series sediment trap (sampling intervals 7-14 days) deployed at 350 m depth from January 2002 to October 2003. The coccolithophore standing stock and coccolith flux varied considerably between sampling periods but, in general, a seasonal pattern was apparent, with low fluxes in spring-summer and maximal values in autumn- winter. During 2002, fluxes ranged from 0.02x108 coccoliths m-2 d-1 in summer to 64.7x108 coccoliths m-2 d-1 in autumn. Values increased considerably during 2003: registering 52.4 x108 coccoliths m-2 d-1 in spring to the highest (128.8x108 coccoliths m-2 d-1) in late summer/autumn. The latter are related to hurricanes that occurred during the sampling period. In total 47 taxa were identified but only three species, Gephyrocapsa oceanica (43.6%), Emiliania huxleyi (28%) and Florisphera profunda (15.7%), constituted 88 percent of the total coccolith flux. This corresponds to the species composition observed in the water column. G. oceanica was always present and its flux pattern followed that of the total flux. The flux of E. huxleyi remained almost constant during the observed time period whereas F. profunda showed peak fluxes in autumn. Although the cosmopolitan species E. huxleyi has been considered the

  4. Harmful Algal Blooms (HABs)

    MedlinePlus

    ... Topics Eighth Annual National Conference on Health Communication, Marketing & Media August 19-21, 2014 Atlanta, GA Harmful Algal Blooms Recommend on Facebook Tweet Share Compartir On this Page What's the ...

  5. Chemical composition of some wild peanut species (Arachis L.) seeds.

    PubMed

    Grosso, N R; Nepote, V; Guzmán, C A

    2000-03-01

    Oil, protein, ash, and carbohydrate contents, iodine value, and fatty acid and sterol compositions were studied in seeds of Arachis trinitensis, A. chiquitana, A. kempff-mercadoi, A. diogoi, A. benensis, A. appressipila, A. valida, A. kretschmeri, A. helodes, A. kuhlmannii, A. williamsii, A. sylvestris, A. matiensis, A. pintoi, A. hoehnei, A. villosa, and A. stenosperma. Oil content was greatest in A.stenosperma (mean value = 51.8%). The protein level was higher in A. sylvestris (30.1%) and A. villosa (29.5%). Mean value of oleic acid varied between 30.6% (A. matiensis) and 46.8% (Arachis villosa), and linoleic acid oscillated between 34.1% (A. villosa) and 47.4% (A. appressipila). The better oleic-to-linoleic (O/L) ratio was exhibited by A. villosa (1.38). Some species showed higher concentration of behenic acid. The greatest level of this fatty acid was found in A. matiensis (6.2%). Iodine value was lower in A. valida (99.2). The sterol composition in the different peanut species showed higher concentration of beta-sitosterol (mean values oscillated between 55.7 and 60.2%) followed by campesterol (12.4-16. 5%), stigmasterol (9.7-13.3%), and Delta(5)-avenasterol (9.7-13.4%). The chemical quality and stability of oils (iodine value and O/L ratio) from wild peanut studied in this work are not better than those of cultivated peanut. PMID:10725154

  6. Differences in the volatile compositions of ginseng species (Panax sp.).

    PubMed

    Cho, In Hee; Lee, Hyun Jeong; Kim, Young-Suk

    2012-08-01

    The volatile compositions in dried white ginseng according to species (Panax ginseng, Panax notoginseng, and Panax quinquefolius) were analyzed and compared by applying multivariate statistical techniques to gas chromatography-mass spectrometry data sets. Main volatile compounds of ginseng species in the present study were sesquiterpenes, such as bicyclogermacrene, (E)-β-farnesene, β-panasinsene, calarene, α-humulene, β-elemene, etc. In particular, α-selinene, α-terpinolene, β-bisabolene, β-phellandrene, β-sesquiphellandrene, zingiberene, germacrene D, limonene, α-gurjunene, (E)-caryophyllene, δ-cadinene, (E)-β-farnesene, α-humulene, bicyclogermacrene, longiborn-8-ene, β-neoclovene, and (+)-spathulenol were mainly associated with the difference between P. ginseng and P. notoginseng versus P. quinquefolius species. On the other hand, the discrimination between P. ginseng and P. notoginseng could be constructed by hexanal, 2-pyrrolidinone, (E)-2-heptenal, (E)-2-octenal, heptanal, isospathulenol, (E,E)-2,4-decadienal, 3-octen-2-one, benzaldehyde, 2-pentylfuran, and (E)-2-nonenal. PMID:22804575

  7. Phylogeography above the species level for perennial species in a composite genus

    PubMed Central

    Tremetsberger, Karin; Ortiz, María Ángeles; Terrab, Anass; Balao, Francisco; Casimiro-Soriguer, Ramón; Talavera, María; Talavera, Salvador

    2016-01-01

    In phylogeography, DNA sequence and fingerprint data at the population level are used to infer evolutionary histories of species. Phylogeography above the species level is concerned with the genealogical aspects of divergent lineages. Here, we present a phylogeographic study to examine the evolutionary history of a western Mediterranean composite, focusing on the perennial species of Helminthotheca (Asteraceae, Cichorieae). We used molecular markers (amplified fragment length polymorphism (AFLP), internal transcribed spacer and plastid DNA sequences) to infer relationships among populations throughout the distributional range of the group. Interpretation is aided by biogeographic and molecular clock analyses. Four coherent entities are revealed by Bayesian mixture clustering of AFLP data, which correspond to taxa previously recognized at the rank of subspecies. The origin of the group was in western North Africa, from where it expanded across the Strait of Gibraltar to the Iberian Peninsula and across the Strait of Sicily to Sicily. Pleistocene lineage divergence is inferred within western North Africa as well as within the western Iberian region. The existence of the four entities as discrete evolutionary lineages suggests that they should be elevated to the rank of species, yielding H. aculeata, H. comosa, H. maroccana and H. spinosa, whereby the latter two necessitate new combinations. PMID:26644340

  8. Phylogeography above the species level for perennial species in a composite genus.

    PubMed

    Tremetsberger, Karin; Ortiz, María Ángeles; Terrab, Anass; Balao, Francisco; Casimiro-Soriguer, Ramón; Talavera, María; Talavera, Salvador

    2015-01-01

    In phylogeography, DNA sequence and fingerprint data at the population level are used to infer evolutionary histories of species. Phylogeography above the species level is concerned with the genealogical aspects of divergent lineages. Here, we present a phylogeographic study to examine the evolutionary history of a western Mediterranean composite, focusing on the perennial species of Helminthotheca (Asteraceae, Cichorieae). We used molecular markers (amplified fragment length polymorphism (AFLP), internal transcribed spacer and plastid DNA sequences) to infer relationships among populations throughout the distributional range of the group. Interpretation is aided by biogeographic and molecular clock analyses. Four coherent entities are revealed by Bayesian mixture clustering of AFLP data, which correspond to taxa previously recognized at the rank of subspecies. The origin of the group was in western North Africa, from where it expanded across the Strait of Gibraltar to the Iberian Peninsula and across the Strait of Sicily to Sicily. Pleistocene lineage divergence is inferred within western North Africa as well as within the western Iberian region. The existence of the four entities as discrete evolutionary lineages suggests that they should be elevated to the rank of species, yielding H. aculeata, H. comosa, H. maroccana and H. spinosa, whereby the latter two necessitate new combinations. PMID:26644340

  9. Industrial-strength ecology: trade-offs and opportunities in algal biofuel production.

    PubMed

    Shurin, Jonathan B; Abbott, Rachel L; Deal, Michael S; Kwan, Garfield T; Litchman, Elena; McBride, Robert C; Mandal, Shovon; Smith, Val H

    2013-11-01

    Microalgae represent one of the most promising groups of candidate organisms for replacing fossil fuels with contemporary primary production as a renewable source of energy. Algae can produce many times more biomass per unit area than terrestrial crop plants, easing the competing demands for land with food crops and native ecosystems. However, several aspects of algal biology present unique challenges to the industrial-scale aquaculture of photosynthetic microorganisms. These include high susceptibility to invading aquatic consumers and weeds, as well as prodigious requirements for nutrients that may compete with the fertiliser demands of other crops. Most research on algal biofuel technologies approaches these problems from a cellular or genetic perspective, attempting either to engineer or select algal strains with particular traits. However, inherent functional trade-offs may limit the capacity of genetic selection or synthetic biology to simultaneously optimise multiple functional traits for biofuel productivity and resilience. We argue that a community engineering approach that manages microalgal diversity, species composition and environmental conditions may lead to more robust and productive biofuel ecosystems. We review evidence for trade-offs, challenges and opportunities in algal biofuel cultivation with a goal of guiding research towards intensifying bioenergy production using established principles of community and ecosystem ecology. PMID:24015819

  10. Viable Compositional Analysis of an Eleven Species Oral Polymicrobial Biofilm

    PubMed Central

    Sherry, Leighann; Lappin, Gillian; O'Donnell, Lindsay E.; Millhouse, Emma; Millington, Owain R.; Bradshaw, David J.; Axe, Alyson S.; Williams, Craig; Nile, Christopher J.; Ramage, Gordon

    2016-01-01

    Purpose: Polymicrobial biofilms are abundant in clinical disease, particularly within the oral cavity. Creating complex biofilm models that recapitulate the polymicrobiality of oral disease are important in the development of new chemotherapeutic agents. In order to do this accurately we require the ability to undertake compositional analysis, in addition to determine individual cell viability, which is difficult using conventional microbiology. The aim of this study was to develop a defined multispecies denture biofilm model in vitro, and to assess viable compositional analysis following defined oral hygiene regimens. Methods: An in vitro multispecies denture biofilm containing various oral commensal and pathogenic bacteria and yeast was created on poly (methyl methacrylate) (PMMA). Denture hygiene regimens tested against the biofilm model included brushing only, denture cleansing only and combinational brushing and denture cleansing. Biofilm composition and viability were assessed by culture (CFU) and molecular (qPCR) methodologies. Scanning electron microscopy and confocal laser scanning microscopy were also employed to visualize changes in denture biofilms following treatment. Results: Combinational treatment of brushing and denture cleansing had the greatest impact on multispecies denture biofilms, reducing the number of live cells by more than 2 logs, and altering the overall composition in favor of streptococci. This was even more evident during the sequential testing, whereby daily sequential treatment reduced the total and live number of bacteria and yeast more than those treated intermittently. Bacteria and yeast remaining following treatment tended to aggregate in the pores of the PMMA, proving more difficult to fully eradicate the biofilm. Conclusions: Overall, we are the first to develop a method to enable viable compositional analysis of an 11 species denture biofilm following chemotherapeutic challenge. We were able to demonstrate viable cell

  11. Discovery of an algicidal compound from Brevibacterium sp. BS01 and its effect on a harmful algal bloom-causing species, Alexandrium tamarense

    PubMed Central

    An, Xinli; Zhang, Bangzhou; Zhang, Huajun; Li, Yi; Zheng, Wei; Yu, Zhiming; Fu, Lijun; Zheng, Tianling

    2015-01-01

    Blooms of the dinoflagellate Alexandrium tamarense have become worldwide phenomena and have detrimental impacts on aquatic ecosystems and human health. In this study, a culture supernatant of the marine actinomycete BS01 exerted a strong algicidal effect on A. tamarense (ATGD98-006). The target algicide from BS01 was separated by adsorption chromatography and identified by MALDI-TOF-MS and NMR analysis. The results suggested that the purified algicidal component corresponded to a hydrophobic compound (2-isobutoxyphenyl)amine (C10H15NO) with a molecular weight of 165 Da, which exhibited a significant algicidal effect (64.5%) on A. tamarense. After incubation in 5 μg/mL of (2-isobutoxyphenyl)amine for 24 h, the algae lost mobility and sank to the bottom of the flasks, and 56.5% of the algae cells lost vitality at a concentration of 20 μg/mL (p < 0.01) despite having intact cell profiles. Morphological analysis revealed that the cell structure of A. tamarense was altered by (2-isobutoxyphenyl)amine resulting in cytoplasm degradation and the loss of organelle integrity. The images following propidium iodide staining suggested that the algal nucleus was also severely damaged and eventually degraded due to exposure to the algicidal compound. All of the results indicate that (2-isobutoxyphenyl)amine from the actinomycete might be a candidate for the control of bloom-forming A. tamarense. PMID:26594205

  12. Discovery of an algicidal compound from Brevibacterium sp. BS01 and its effect on a harmful algal bloom-causing species, Alexandrium tamarense.

    PubMed

    An, Xinli; Zhang, Bangzhou; Zhang, Huajun; Li, Yi; Zheng, Wei; Yu, Zhiming; Fu, Lijun; Zheng, Tianling

    2015-01-01

    Blooms of the dinoflagellate Alexandrium tamarense have become worldwide phenomena and have detrimental impacts on aquatic ecosystems and human health. In this study, a culture supernatant of the marine actinomycete BS01 exerted a strong algicidal effect on A. tamarense (ATGD98-006). The target algicide from BS01 was separated by adsorption chromatography and identified by MALDI-TOF-MS and NMR analysis. The results suggested that the purified algicidal component corresponded to a hydrophobic compound (2-isobutoxyphenyl)amine (C10H15NO) with a molecular weight of 165 Da, which exhibited a significant algicidal effect (64.5%) on A. tamarense. After incubation in 5 μg/mL of (2-isobutoxyphenyl)amine for 24 h, the algae lost mobility and sank to the bottom of the flasks, and 56.5% of the algae cells lost vitality at a concentration of 20 μg/mL (p < 0.01) despite having intact cell profiles. Morphological analysis revealed that the cell structure of A. tamarense was altered by (2-isobutoxyphenyl)amine resulting in cytoplasm degradation and the loss of organelle integrity. The images following propidium iodide staining suggested that the algal nucleus was also severely damaged and eventually degraded due to exposure to the algicidal compound. All of the results indicate that (2-isobutoxyphenyl)amine from the actinomycete might be a candidate for the control of bloom-forming A. tamarense. PMID:26594205

  13. Algal Bloom Detection from HICO

    NASA Astrophysics Data System (ADS)

    Amin, Ruhul; Gould, Richard

    2014-05-01

    Ocean color satellites provide daily, global views of marine bio-optical properties in the upper ocean at various spatial scales. The most productive area of the global ocean is the coastal zone which is heavily impacted by urban and agricultural runoff, transportation, recreation, and oil and gas production. In recent years, harmful algal blooms (HABs) have become one of the serious environmental problems in the coastal areas on a global scale. The global nature of the problem has expanded in its frequency, severity, and extent over the last several decades. Human activities and population increases have contributed to an increase in various toxic and noxious algal species in the coastal regions worldwide. Eutrophication in estuaries and coastal waters is believed to be the major factor causing HABs. In this study, we assess the applicability of the Red Band Difference (RBD) HAB detection algorithm on data from the Hyperspectral Imager for the Coastal Ocean (HICO). Our preliminary results show that due to various uncertainties such as atmospheric correction, calibration and possibly also the relatively low signal-to-noise ratio of HICO for fluorescence detection, it is difficult to extract the fluorescence portion of the reflectance spectrum that RBD uses for bloom detection. We propose an improved bloom detection technique for HICO using red and NIR bands. Our results are validated using other space-borne and ground based measurements.

  14. Algal Biofuels Fact Sheet

    SciTech Connect

    2009-10-27

    This fact sheet provides information on algal biofuels, which are generating considerable interest around the world. They may represent a sustainable pathway for helping to meet the U.S. biofuel production targets set by the Energy Independence and Security Act of 2007.

  15. Algal toxins alter copepod feeding behavior.

    PubMed

    Hong, Jiarong; Talapatra, Siddharth; Katz, Joseph; Tester, Patricia A; Waggett, Rebecca J; Place, Allen R

    2012-01-01

    Using digital holographic cinematography, we quantify and compare the feeding behavior of free-swimming copepods, Acartia tonsa, on nutritional prey (Storeatula major) to that occurring during exposure to toxic and non-toxic strains of Karenia brevis and Karlodinium veneficum. These two harmful algal species produce polyketide toxins with different modes of action and potency. We distinguish between two different beating modes of the copepod's feeding appendages-a "sampling beating" that has short durations (<100 ms) and involves little fluid entrainment and a longer duration "grazing beating" that persists up to 1200 ms and generates feeding currents. The durations of both beating modes have log-normal distributions. Without prey, A. tonsa only samples the environment at low frequency. Upon introduction of non-toxic food, it increases its sampling time moderately and the grazing period substantially. On mono algal diets for either of the toxic dinoflagellates, sampling time fraction is high but the grazing is very limited. A. tonsa demonstrates aversion to both toxic algal species. In mixtures of S. major and the neurotoxin producing K. brevis, sampling and grazing diminish rapidly, presumably due to neurological effects of consuming brevetoxins while trying to feed on S. major. In contrast, on mixtures of cytotoxin producing K. veneficum, both behavioral modes persist, indicating that intake of karlotoxins does not immediately inhibit the copepod's grazing behavior. These findings add critical insight into how these algal toxins may influence the copepod's feeding behavior, and suggest how some harmful algal species may alter top-down control exerted by grazers like copepods. PMID:22629336

  16. The Influences of Canopy Species and Topographic Variables on Understory Species Diversity and Composition in Coniferous Forests

    PubMed Central

    Huo, Hong; Feng, Qi; Su, Yong-hong

    2014-01-01

    Understanding the factors that influence the distribution of understory vegetation is important for biological conservation and forest management. We compared understory species composition by multi-response permutation procedure and indicator species analysis between plots dominated by Qinghai spruce (Picea crassifolia Kom.) and Qilian juniper (Sabina przewalskii Kom.) in coniferous forests of the Qilian Mountains, northwestern China. Understory species composition differed markedly between the forest types. Many heliophilous species were significantly associated with juniper forest, while only one species was indicative of spruce forest. Using constrained ordination and the variation partitioning model, we quantitatively assessed the relative effects of two sets of explanatory variables on understory species composition. The results showed that topographic variables had higher explanatory power than did site conditions for understory plant distributions. However, a large amount of the variation in understory species composition remained unexplained. Forward selection revealed that understory species distributions were primarily affected by elevation and aspect. Juniper forest had higher species richness and α-diversity and lower β-diversity in the herb layer of the understory plant community than spruce forest, suggesting that the former may be more important in maintaining understory biodiversity and community stability in alpine coniferous forest ecosystems. PMID:25097871

  17. Comparison of the volatile oil composition of three Atalantia species.

    PubMed

    Das, Arun K; Swamy, P S

    2013-05-01

    The members of the genus Atalantia belonging to the family Rutaceae have many uses in traditional medicine. The aim of the present study was to investigate and compare the chemical composition of essential oils of three species of Atalantia namely Atalantia monophylla (Roxb.) DC., Atalantia racemosa Wight. and Atalantia wightii Tanaka. The extract percentage of the obtained essential oil was found to be 0.2, 0.17 and 0.31% in A. monophylla, A. racemosa and A. wightii respectively. The major compounds identified were alpha-Asarone (28.82%), Sabinene (13.19%), Eugenol methyl ether (12.71%), 1,2-Dimethoxy-4-(2-methoxyethenyl)benzene (11.63%) and beta-Pinene (5.3%) in the essential oil of A. monophylla. In A. racemosa, T-Cadinol (11.08%), Caryophyllene oxide (9.78%), beta-Caryophyllene (9.20%), Spathulenol (7.21%), beta-Phellandrene (5.67%) and Decanal (4.01%) and in A. wightii beta-Caryophyllene (16.37%), D-Limnonene (12.15%), Decanal (10.49%), beta-Myrcene (7.67%), Tetradecanal (6.99%), Caryophyllene oxide (6.29%) and Hexadecylene oxide (5.87%) were the main constituents. Sesquiterpenes were the major class of compounds in A. racemosa and A. wightii, while in A. monophylla the essential oil was predominated by ether compounds. The results showed that GC/MS analysis of essential oils is a significant step in the bio-chemical profiling and bio-prospecting of Atalantia species. PMID:24617143

  18. Effects of “Reduced” and “Business-As-Usual” CO2 Emission Scenarios on the Algal Territories of the Damselfish Pomacentrus wardi (Pomacentridae)

    PubMed Central

    Bender, Dorothea; Champ, Connor Michael; Kline, David; Diaz-Pulido, Guillermo; Dove, Sophie

    2015-01-01

    Turf algae are a very important component of coral reefs, featuring high growth and turnover rates, whilst covering large areas of substrate. As food for many organisms, turf algae have an important role in the ecosystem. Farming damselfish can modify the species composition and productivity of such algal assemblages, while defending them against intruders. Like all organisms however, turf algae and damselfishes have the potential to be affected by future changes in seawater (SW) temperature and pCO2. In this study, algal assemblages, in the presence and absence of farming Pomacentrus wardi were exposed to two combinations of SW temperature and pCO2 levels projected for the austral spring of 2100 (the B1 “reduced” and the A1FI “business-as-usual” CO2 emission scenarios) at Heron Island (GBR, Australia). These assemblages were dominated by the presence of red algae and non-epiphytic cyanobacteria, i.e. cyanobacteria that grow attached to the substrate rather than on filamentous algae. The endpoint algal composition was mostly controlled by the presence/absence of farming damselfish, despite a large variability found between the algal assemblages of individual fish. Different scenarios appeared to be responsible for a mild, species specific change in community composition, observable in some brown and green algae, but only in the absence of farming fish. Farming fish appeared unaffected by the conditions to which they were exposed. Algal biomass reductions were found under “reduced” CO2 emission, but not “business-as-usual” scenarios. This suggests that action taken to limit CO2 emissions may, if the majority of algae behave similarly across all seasons, reduce the potential for phase shifts that lead to algal dominated communities. At the same time the availability of food resources to damselfish and other herbivores would be smaller under “reduced” emission scenarios. PMID:26121163

  19. Effects of "Reduced" and "Business-As-Usual" CO2 Emission Scenarios on the Algal Territories of the Damselfish Pomacentrus wardi (Pomacentridae).

    PubMed

    Bender, Dorothea; Champ, Connor Michael; Kline, David; Diaz-Pulido, Guillermo; Dove, Sophie

    2015-01-01

    Turf algae are a very important component of coral reefs, featuring high growth and turnover rates, whilst covering large areas of substrate. As food for many organisms, turf algae have an important role in the ecosystem. Farming damselfish can modify the species composition and productivity of such algal assemblages, while defending them against intruders. Like all organisms however, turf algae and damselfishes have the potential to be affected by future changes in seawater (SW) temperature and pCO2. In this study, algal assemblages, in the presence and absence of farming Pomacentrus wardi were exposed to two combinations of SW temperature and pCO2 levels projected for the austral spring of 2100 (the B1 "reduced" and the A1FI "business-as-usual" CO2 emission scenarios) at Heron Island (GBR, Australia). These assemblages were dominated by the presence of red algae and non-epiphytic cyanobacteria, i.e. cyanobacteria that grow attached to the substrate rather than on filamentous algae. The endpoint algal composition was mostly controlled by the presence/absence of farming damselfish, despite a large variability found between the algal assemblages of individual fish. Different scenarios appeared to be responsible for a mild, species specific change in community composition, observable in some brown and green algae, but only in the absence of farming fish. Farming fish appeared unaffected by the conditions to which they were exposed. Algal biomass reductions were found under "reduced" CO2 emission, but not "business-as-usual" scenarios. This suggests that action taken to limit CO2 emissions may, if the majority of algae behave similarly across all seasons, reduce the potential for phase shifts that lead to algal dominated communities. At the same time the availability of food resources to damselfish and other herbivores would be smaller under "reduced" emission scenarios. PMID:26121163

  20. Factors affecting Archaeal Lipid Compositions of the Sulfolobus Species

    NASA Astrophysics Data System (ADS)

    He, L.; Han, J.; Wei, Y.; Lin, L.; Wei, Y.; Zhang, C.

    2010-12-01

    Temperature is the best known variable affecting the distribution of the archaeal glycerol dibiphytanyl glycerol tetraethers (GDGTs) in marine and freshwater systems. Other variables such as pH, ionic strength, or bicarbonate concentration may also affect archaeal GDGTs in terrestrial systems. Studies of pure cultures can help us pinpoint the specific effects these variables may have on archaeal lipid distribution in natural environments. In this study, three Sulfolobus species (HG4, HB5-2, HB9-6) isolated from Tengchong hot springs (pH 2-3, temperature 73-90°C) in China were used to investigate the effects of temperature, pH, substrate, and type of strain on the composition of GDGTs. Results showed that increase in temperature had negative effects on the relative contents of GDGT-0 (no cyclopentyl rings), GDGT-1 (one cyclopentyl ring), GDGT-2 and GDGT-3 but positive effects on GDGT-4, GDGT-4', GDGT-5 and GDGT-5'. Increase in pH, on the other hand, had negative effects on GDGT-0, GDGT-1, GDGT-4', GDGT-5 and GDGT-5', and positive effects on GDGT-3 and GDGT-4. GDGT-2 remained relatively constant with changing pH. When the HG4 was grown on different substrates, GDGT-5 was five time more abundant in sucrose-grown cultures than in yeast extract- or sulfur- grown cultures, suggesting that carbohydrates may stimulate the production of GDGT-5. For all three species, the ring index (average number of rings) of GDGTs correlated positively with incubation temperature. In HG4, ring index was much lower at optimal pH (3.5) than at other pH values. Ring index of HB5-2 or HB9-6 is higher than that of HG4, suggesting that speciation may affect the degree of cyclization of GDGT of the Sulfolobus. These results indicate that individual archaeal lipids respond differently to changes in environmental variables, which may be also species specific.

  1. DNA nucleoside composition and methylation in several species of microalgae

    SciTech Connect

    Jarvis, E.E.; Dunahay, T.G.; Brown, L.M. )

    1992-06-01

    Total DNA was isolated from 10 species of microalgae, including representatives of the Chlorophyceae (Chlorella ellipsoidea, Chlamydomonas reinhardtii, and Monoraphidium minutum), Bacillariophyceae (Cyclotella cryptica, Navicula saprophila, Nitzschia pusilla, and Phaeodactylum tricornutum), Charophyceae (Stichococcus sp.), Dinophyceae (Crypthecodinium cohnii), and Prasinophyceae (Tetraselmis suecica). Control samples of Escherichia coli and calf thymus DNA were also analyzed. The nucleoside base composition of each DNA sample was determined by reversed-phase high performance liquid chromatography. All samples contained 5-methyldeoxycytidine, although at widely varying levels. In M. minutum, about one-third of the cytidine residues were methylated. Restriction analysis supported this high degree of methylation in M. minutum and suggested that methylation is biased toward 5[prime]-CG dinucleotides. The guanosine + cytosine (GC) contents of the green algae were, with the exception of Stichococcus sp., consistently higher than those of the diatoms. Monoraphidium minutum exhibited an extremely high GC content of 71%. Such a value is rare among eukaryotic organisms and might indicate an unusual codon usage. This work is important for developing strategies for transformation and gene cloning in these algae. 46 refs., 1 fig., 2 tabs.

  2. Algal functional annotation tool

    2012-07-12

    Abstract BACKGROUND: Progress in genome sequencing is proceeding at an exponential pace, and several new algal genomes are becoming available every year. One of the challenges facing the community is the association of protein sequences encoded in the genomes with biological function. While most genome assembly projects generate annotations for predicted protein sequences, they are usually limited and integrate functional terms from a limited number of databases. Another challenge is the use of annotations tomore » interpret large lists of 'interesting' genes generated by genome-scale datasets. Previously, these gene lists had to be analyzed across several independent biological databases, often on a gene-by-gene basis. In contrast, several annotation databases, such as DAVID, integrate data from multiple functional databases and reveal underlying biological themes of large gene lists. While several such databases have been constructed for animals, none is currently available for the study of algae. Due to renewed interest in algae as potential sources of biofuels and the emergence of multiple algal genome sequences, a significant need has arisen for such a database to process the growing compendiums of algal genomic data. DESCRIPTION: The Algal Functional Annotation Tool is a web-based comprehensive analysis suite integrating annotation data from several pathway, ontology, and protein family databases. The current version provides annotation for the model alga Chlamydomonas reinhardtii, and in the future will include additional genomes. The site allows users to interpret large gene lists by identifying associated functional terms, and their enrichment. Additionally, expression data for several experimental conditions were compiled and analyzed to provide an expression-based enrichment search. A tool to search for functionally-related genes based on gene expression across these conditions is also provided. Other features include dynamic visualization of genes on

  3. Algal functional annotation tool

    SciTech Connect

    2012-07-12

    Abstract BACKGROUND: Progress in genome sequencing is proceeding at an exponential pace, and several new algal genomes are becoming available every year. One of the challenges facing the community is the association of protein sequences encoded in the genomes with biological function. While most genome assembly projects generate annotations for predicted protein sequences, they are usually limited and integrate functional terms from a limited number of databases. Another challenge is the use of annotations to interpret large lists of 'interesting' genes generated by genome-scale datasets. Previously, these gene lists had to be analyzed across several independent biological databases, often on a gene-by-gene basis. In contrast, several annotation databases, such as DAVID, integrate data from multiple functional databases and reveal underlying biological themes of large gene lists. While several such databases have been constructed for animals, none is currently available for the study of algae. Due to renewed interest in algae as potential sources of biofuels and the emergence of multiple algal genome sequences, a significant need has arisen for such a database to process the growing compendiums of algal genomic data. DESCRIPTION: The Algal Functional Annotation Tool is a web-based comprehensive analysis suite integrating annotation data from several pathway, ontology, and protein family databases. The current version provides annotation for the model alga Chlamydomonas reinhardtii, and in the future will include additional genomes. The site allows users to interpret large gene lists by identifying associated functional terms, and their enrichment. Additionally, expression data for several experimental conditions were compiled and analyzed to provide an expression-based enrichment search. A tool to search for functionally-related genes based on gene expression across these conditions is also provided. Other features include dynamic visualization of genes on KEGG

  4. Temporal and Spatial Dynamics of Tree Species Composition in Temperate Mountains of South Korea

    NASA Astrophysics Data System (ADS)

    Lee, Boknam; Park, Juhan; Cho, Sungsik; Ryu, Daun; Zaw Wynn, Khine; Park, Minji; Cho, Sunhee; Yoon, Jongguk; Park, Jongyoung; Kim, Hyun Seok

    2015-04-01

    Long term studies on vegetation dynamics are important to identify changes of ecosystem-level responses to climate change. To learn how tree species composition and stand structure change across temperate mountains, the temporal and spatial variations in tree species diversity and structure were investigated using the species composition and DBH size collected over the fourteen-year period across 134 sites in Jiri and Baekoon Mountains, South Korea. The overall temporal changes over fourteen years showed significant increase in stand density, species diversity and evenness according to the indices of Shannon-Weiner diversity, Bray-Curtis dissimilarity, and Pielou's evenness, contributing to the increase of basal area and biomass growth. The change of tree species composition could be categorized into five species communities, representing gradual increase or decrease, establishment, extinction, fluctuation of species population. However, in general, the change in species composition appeared to have consistent and directional patterns of increase in the annual rate of change in the mean species traits including species richness, pole growth rate, adult growth rate, and adult stature with five common dominant species (Quercus mongolica, Quercus variabilis, Quercus serrata, Carpinus laxiflora, and Styrax japonicus). The spatial patterns of species composition appeared to have a higher stand density and species diversity along with the low latitude and high slope ecosystem. The climate change was another main driver to vary the distribution of species abundance. Overall, both temporal and spatial changes of composition in tree species community was clear and further analysis to clarify the reasons for such fast and species-specific changes is underway especially to separate the effect of successional change and climate change. Keywords species composition; climate change; temporal and spatial variation ; forest structure; temperate forest

  5. DNA-Based Taxonomy in Ecologically Versatile Microalgae: A Re-Evaluation of the Species Concept within the Coccoid Green Algal Genus Coccomyxa (Trebouxiophyceae, Chlorophyta)

    PubMed Central

    Rindi, Fabio; Tempesta, Sabrina; Paoletti, Michela; Pasqualetti, Marcella

    2016-01-01

    Coccomyxa is a genus of unicellular green algae of the class Trebouxiophyceae, well known for its cosmopolitan distribution and great ecological amplitude. The taxonomy of this genus has long been problematic, due to reliance on badly-defined and environmentally variable morphological characters. In this study, based on the discovery of a new species from an extreme habitat, we reassess species circumscription in Coccomyxa, a unicellular genus of the class Trebouxiophyceae, using a combination of ecological and DNA sequence data (analyzed with three different methods of algorithmic species delineation). Our results are compared with those of a recent integrative study of Darienko and colleagues that reassessed the taxonomy of Coccomyxa, recognizing 7 species in the genus. Expanding the dataset from 43 to 61 sequences (SSU + ITS rDNA) resulted in a different delimitation, supporting the recognition of a higher number of species (24 to 27 depending on the analysis used, with the 27-species scenario receiving the strongest support). Among these, C. melkonianii sp. nov. is described from material isolated from a river highly polluted by heavy metals (Rio Irvi, Sardinia, Italy). Analyses performed on ecological characters detected a significant phylogenetic signal in six different characters. We conclude that the 27-species scenario is presently the most realistic for Coccomyxa and we suggest that well-supported lineages distinguishable by ecological preferences should be recognized as different species in this genus. We also recommend that for microbial lineages in which the overall diversity is unknown and taxon sampling is sparse, as is often the case for green microalgae, the results of analyses for algorithmic DNA-based species delimitation should be interpreted with extreme caution. PMID:27028195

  6. DNA-Based Taxonomy in Ecologically Versatile Microalgae: A Re-Evaluation of the Species Concept within the Coccoid Green Algal Genus Coccomyxa (Trebouxiophyceae, Chlorophyta).

    PubMed

    Malavasi, Veronica; Škaloud, Pavel; Rindi, Fabio; Tempesta, Sabrina; Paoletti, Michela; Pasqualetti, Marcella

    2016-01-01

    Coccomyxa is a genus of unicellular green algae of the class Trebouxiophyceae, well known for its cosmopolitan distribution and great ecological amplitude. The taxonomy of this genus has long been problematic, due to reliance on badly-defined and environmentally variable morphological characters. In this study, based on the discovery of a new species from an extreme habitat, we reassess species circumscription in Coccomyxa, a unicellular genus of the class Trebouxiophyceae, using a combination of ecological and DNA sequence data (analyzed with three different methods of algorithmic species delineation). Our results are compared with those of a recent integrative study of Darienko and colleagues that reassessed the taxonomy of Coccomyxa, recognizing 7 species in the genus. Expanding the dataset from 43 to 61 sequences (SSU + ITS rDNA) resulted in a different delimitation, supporting the recognition of a higher number of species (24 to 27 depending on the analysis used, with the 27-species scenario receiving the strongest support). Among these, C. melkonianii sp. nov. is described from material isolated from a river highly polluted by heavy metals (Rio Irvi, Sardinia, Italy). Analyses performed on ecological characters detected a significant phylogenetic signal in six different characters. We conclude that the 27-species scenario is presently the most realistic for Coccomyxa and we suggest that well-supported lineages distinguishable by ecological preferences should be recognized as different species in this genus. We also recommend that for microbial lineages in which the overall diversity is unknown and taxon sampling is sparse, as is often the case for green microalgae, the results of analyses for algorithmic DNA-based species delimitation should be interpreted with extreme caution. PMID:27028195

  7. Algal taxonomy: a road to nowhere?

    PubMed

    De Clerck, Olivier; Guiry, Michael D; Leliaert, Frederik; Samyn, Yves; Verbruggen, Heroen

    2013-04-01

    The widespread view of taxonomy as an essentially retrogressive and outmoded science unable to cope with the current biodiversity crisis stimulated us to analyze the current status of cataloguing global algal diversity. Contrary to this largely pessimistic belief, species description rates of algae through time and trends in the number of active taxonomists, as revealed by the web resource AlgaeBase, show a much more positive picture. More species than ever before are being described by a large community of algal taxonomists. The lack of any decline in the rate at which new species and genera are described, however, is indicative of the large proportion of undiscovered diversity and bears heavily on any prediction of global algal species diversity and the time needed to catalogue it. The saturation of accumulation curves of higher taxa (family, order, and classes) on the other hand suggest that at these taxonomic levels most diversity has been discovered. This reasonably positive picture does not imply that algal taxonomy does not face serious challenges in the near future. The observed levels of cryptic diversity in algae, combined with the shift in methods used to characterize them, have resulted in a rampant uncertainty about the status of many older species. As a consequence, there is a tendency in phycology to move gradually away from traditional names to a more informal system whereby clade-, specimen- or strain-based identifiers are used to communicate biological information. Whether these informal names for species-level clades represent a temporary situation stimulated by the lag between species discovery and formal description, or an incipient alternative or parallel taxonomy, will be largely determined by how well we manage to integrate historical collections into modern taxonomic research. Additionally, there is a pressing need for a consensus about the organizational framework to manage the information about algal species names. An eventual strategy

  8. Altered Lipid Composition and Enhanced Nutritional Value of Arabidopsis Leaves following Introduction of an Algal Diacylglycerol Acyltransferase 2[C][W

    PubMed Central

    Sanjaya; Miller, Rachel; Durrett, Timothy P.; Kosma, Dylan K.; Lydic, Todd A.; Muthan, Bagyalakshmi; Koo, Abraham J.K.; Bukhman, Yury V.; Reid, Gavin E.; Howe, Gregg A.; Ohlrogge, John; Benning, Christoph

    2013-01-01

    Enhancement of acyl-CoA–dependent triacylglycerol (TAG) synthesis in vegetative tissues is widely discussed as a potential avenue to increase the energy density of crops. Here, we report the identification and characterization of Chlamydomonas reinhardtii diacylglycerol acyltransferase type two (DGTT) enzymes and use DGTT2 to alter acyl carbon partitioning in plant vegetative tissues. This enzyme can accept a broad range of acyl-CoA substrates, allowing us to interrogate different acyl pools in transgenic plants. Expression of DGTT2 in Arabidopsis thaliana increased leaf TAG content, with some molecular species containing very-long-chain fatty acids. The acyl compositions of sphingolipids and surface waxes were altered, and cutin was decreased. The increased carbon partitioning into TAGs in the leaves of DGTT2-expressing lines had little effect on transcripts of the sphingolipid/wax/cutin pathway, suggesting that the supply of acyl groups for the assembly of these lipids is not transcriptionally adjusted. Caterpillars of the generalist herbivore Spodoptera exigua reared on transgenic plants gained more weight. Thus, the nutritional value and/or energy density of the transgenic lines was increased by ectopic expression of DGTT2 and acyl groups were diverted from different pools into TAGs, demonstrating the interconnectivity of acyl metabolism in leaves. PMID:23417035

  9. Fatty acid composition of twelve algae from the coastal zones of Qatar.

    PubMed

    Heiba, H I; Al-Easa, H S; Rizk, A F

    1997-01-01

    Fatty acid compositions of twelve algal species from two different classes were determined. Three Chlorophyta species (Acetabularia calyculus, Cladophora sericoides and Dictyosphaeria cavernosa) and nine Phaeophyta species (Colpomenia sinuosa, Cystoseria trinodis, Dictyota cervicornis, Hormophysa triquetra, Padina gymnospora, Sargassum binderi, S. boveanum, S. denticulatum and S. heteromorpha) were investigated. Thirty-four fatty acids were identified. Myristic, palmitic, oleic, linoleic, eicosodienic and lignoceric acids were predominant in all examined algal species. Branched saturated fatty acids were also found in all investigated species except Cladophora sericoides. PMID:9498691

  10. National Algal Biofuels Technology Roadmap

    SciTech Connect

    Ferrell, John; Sarisky-Reed, Valerie

    2010-05-01

    The framework for National Algal Biofuels Technology Roadmap was constructed at the Algal Biofuels Technology Roadmap Workshop, held December 9-10, 2008, at the University of Maryland-College Park. The Workshop was organized by the Biomass Program to discuss and identify the critical challenges currently hindering the development of a domestic, commercial-scale algal biofuels industry. This Roadmap presents information from a scientific, economic, and policy perspectives that can support and guide RD&D investment in algal biofuels. While addressing the potential economic and environmental benefits of using algal biomass for the production of liquid transportation fuels, the Roadmap describes the current status of algae RD&D. In doing so, it lays the groundwork for identifying challenges that likely need to be overcome for algal biomass to be used in the production of economically viable biofuels.

  11. Specificity is rarely absolute in coral–algal symbiosis: implications for coral response to climate change

    PubMed Central

    Silverstein, Rachel N.; Correa, Adrienne M. S.; Baker, Andrew C.

    2012-01-01

    Some reef-building corals have been shown to respond to environmental change by shifting the composition of their algal symbiont (genus Symbiodinium) communities. These shifts have been proposed as a potential mechanism by which corals might survive climate stressors, such as increased temperatures. Conventional molecular methods suggest this adaptive capacity may not be widespread because few (∼25%) coral species have been found to associate with multiple Symbiodinium clades. However, these methods can fail to detect low abundance symbionts (typically less than 10–20% of the total algal symbiont community). To determine whether additional Symbiodinium clades are present, but are not detected using conventional techniques, we applied a high-resolution, real-time PCR assay to survey Symbiodinium (in clades A–D) from 39 species of phylogenetically and geographically diverse scleractinian corals. This survey included 26 coral species thought to be restricted to hosting a single Symbiodinium clade (‘symbiotic specialists’). We detected at least two Symbiodinium clades (C and D) in at least one sample of all 39 coral species tested; all four Symbiodinium clades were detected in over half (54%) of the 26 symbiotic specialist coral species. Furthermore, on average, 68 per cent of all sampled colonies within a given coral species hosted two or more symbiont clades. We conclude that the ability to associate with multiple symbiont clades is common in scleractinian (stony) corals, and that, in coral–algal symbiosis, ‘specificity’ and ‘flexibility’ are relative terms: specificity is rarely absolute. The potential for reef corals to adapt or acclimatize to environmental change via symbiont community shifts may therefore be more phylogenetically widespread than has previously been assumed. PMID:22367985

  12. Measuring Cellular-scale Nutrient Distribution in Algal Biofilms with Synchrotron Confocal Infrared Microspectroscopy

    SciTech Connect

    J Murdock; W Dodds; J Reffner; D Wetzel

    2011-12-31

    The microscope and infrared spectrometer are two of the most useful tools for the study of biological materials, and their combined analytical power far exceeds the sum of the two. Performing molecular spectroscopy through a microscope superimposes chemical information onto the physical microstructure obtained from the optical microscope when visible and infrared information are collected under the same conditions. The instrument developments that enable current infrared microspectroscopic studies began with the introduction of the first research-grade infrared microscope, patented in 1989 (1). By 1993, published reports using this method to determine macroalgae (seaweed) cell-wall composition appeared (2-4). Since these initial reports, the use of infrared microspectroscopy (IMS) in microalgal (single cells or groups of cells) research has grown. Primarily, cultured algae have been used to hone IMS methodology and evaluate its capabilities in algal research (5-8). Studies involving natural, mixed species assemblages, which can utilize the spatial resolution potential of this technique fully are rare (9-11). For instance, in a recent review of IMS microalgal ecological research (12), only 3 of the 29 peer-reviewed publications investigated natural algal assemblages. Both thermal and synchrotron infrared sources provide a resolution capable of measuring individual algae in mixed species assemblages, and each has its advantages. For example, thermal source IMS is more accessible, allowing more samples to be analyzed than synchrotron IMS. However, synchrotron IMS with confocal masking provides superior resolution, which can be critical in isolating small or contiguous cells. Algal ecology is the study of the interaction between algae and their environment. Infrared microspectroscopy addresses a major logistical problem in this field, obtaining species-specific cellular biochemical information from natural, mixed-species assemblages (11,12). Benthic (bottom

  13. Urban wastewater treatment by seven species of microalgae and an algal bloom: Biomass production, N and P removal kinetics and harvestability.

    PubMed

    Mennaa, Fatima Zahra; Arbib, Zouhayr; Perales, José Antonio

    2015-10-15

    This study evaluates the capacity of seven species and a Bloom of microalgae to grow in urban wastewater. Nutrient removal kinetics and biomass harvesting by means of centrifugation and coagulation-flocculation-sedimentation have been also tested. Results show that the best biomass productivities ranged from between 118 and 108 mgSS L(-1) d(-1) for the Bloom (Bl) and Scenedesmus obliquus (Sco). Regarding nutrient removal, microalgae were able to remove the total dissolved phosphorus and nitrogen concentrations by more than 80% and 87% respectively, depending on the species tested. The final total dissolved concentration of nitrogen and phosphorus in the culture media complies with the European Commission Directive 98/15/CE on urban wastewater treatment. Regarding harvesting, the results of coagulation-flocculation sedimentation using a 60 mg L(-1) dose of Ferric chloride were similar between species, exceeding the biomass removal efficiency by more than 90%. The results of centrifugation (time required to remove 90% of solids at 1000 rpm) were not similar between species, with the shortest time being 2.9 min for Sco, followed by the bloom (7.25 min). An overall analysis suggested that the natural bloom and Scenedesmus obliquus seem to be the best candidates to grow in pre-treated wastewater, according to their biomass production, nutrient removal capability and harvestability. PMID:26117372

  14. Distribution, behavior, and condition of herbivorous fishes on coral reefs track algal resources.

    PubMed

    Tootell, Jesse S; Steele, Mark A

    2016-05-01

    Herbivore distribution can impact community structure and ecosystem function. On coral reefs, herbivores are thought to play an important role in promoting coral dominance, but how they are distributed relative to algae is not well known. Here, we evaluated whether the distribution, behavior, and condition of herbivorous fishes correlated with algal resource availability at six sites in the back reef environment of Moorea, French Polynesia. Specifically, we tested the hypotheses that increased algal turf availability would coincide with (1) increased biomass, (2) altered foraging behavior, and (3) increased energy reserves of herbivorous fishes. Fish biomass and algal cover were visually estimated along underwater transects; behavior of herbivorous fishes was quantified by observations of focal individuals; fish were collected to assess their condition; and algal turf production rates were measured on standardized tiles. The best predictor of herbivorous fish biomass was algal turf production, with fish biomass increasing with algal production. Biomass of herbivorous fishes was also negatively related to sea urchin density, suggesting competition for limited resources. Regression models including both algal turf production and urchin density explained 94 % of the variation in herbivorous fish biomass among sites spread over ~20 km. Behavioral observations of the parrotfish Chlorurus sordidus revealed that foraging area increased as algal turf cover decreased. Additionally, energy reserves increased with algal turf production, but declined with herbivorous fish density, implying that algal turf is a limited resource for this species. Our findings support the hypothesis that herbivorous fishes can spatially track algal resources on coral reefs. PMID:26271287

  15. Species composition of Black Sea marine planktonic copepods

    NASA Astrophysics Data System (ADS)

    Gubanova, A.; Altukhov, D.; Stefanova, K.; Arashkevich, E.; Kamburska, L.; Prusova, I.; Svetlichny, L.; Timofte, F.; Uysal, Z.

    2014-07-01

    This paper reviews the changes in the marine planktonic copepods of the Black Sea species' list from the beginning of taxonomic research to the present day. The study was based on the SESAME biological database, unpublished data, literature and data obtained during the course of the SESAME project. Comparisons were made with the Guidebook for Marine Fauna of the Black Sea and the Sea of Azov, which revealed changes both in the taxonomic status of some species and in the structure of the copepod community. The taxonomic status of two species (Acartia clausi small form and Centropages kroyeri pontica) and the nomenclature of two species (Oihona minuta and Calanus helgolandicus) have been changed. Three native species (Acartia margalefi, Oithona nana, and Paracartia latisetosa) have disappeared. Two non-indigenous copepods (Acartia tonsa and Oithona davisae) became established in the Black Sea ecosystem in the 1970s and 2000s, respectively. The success of their establishment was determined by biological features of the species and vulnerability of the native copepod community to invasions. It is highly probable that both species were introduced to the Black Sea by vessel ballast water. The hypothesis of "mediterranization" of the Black Sea fauna does not appear to hold true for zooplankton. Numerous claims of alien copepod species in the Black Sea remain largely unverified due to insufficient information. Data on newly discovered species of the Acartia genus are not authenticated. An updated list of marine planktonic copepods of the Black Sea is hereby presented.

  16. TEMPERATURE AND MANGANESE AS DETERMINING FACTORS IN THE PRESENCE OF DIATOM OR BLUE-GREEN ALGAL FLORAS IN STREAMS*

    PubMed Central

    Patrick, Ruth; Crum, Bowman; Coles, John

    1969-01-01

    Diatoms are usually the major component of the algal flora in many streams, although green and blue-green algae may be present. These experiments were designed to determine if high temperature or a shift in the chemical composition of the water might bring about a dominance of blue-green algae and/or green algae rather than a dominance of diatoms in the algal flora. The results of these experiments indicate that an average temperature of 34° to 38°C results in a shift of dominance in the algal flora from diatoms to blue-green algae. Furthermore, a blue-green and green algal flora of species typically found in organically polluted water in favored if the manganese content is a few parts per billion. If the manganese content averaged 0.02-0.043 mg/liter in the natural stream to 0.04-0.28 mg/liter in the recycled water experiment, a diatom flora remained dominant. PMID:16591790

  17. Living in biological soil crust communities of African deserts-Physiological traits of green algal Klebsormidium species (Streptophyta) to cope with desiccation, light and temperature gradients.

    PubMed

    Karsten, Ulf; Herburger, Klaus; Holzinger, Andreas

    2016-05-01

    Green algae of the genus Klebsormidium (Klebsormidiales, Streptophyta) are typical members of biological soil crusts (BSCs) worldwide. The phylogeny and ecophysiology of Klebsormidium has been intensively studied in recent years, and a new lineage called superclade G, which was isolated from BSCs in arid southern Africa and comprising undescribed species, was reported. Three different African strains, that have previously been isolated from hot-desert BSCs and molecular-taxonomically characterized, were comparatively investigated. In addition, Klebsormidium subtilissimum from a cold-desert habitat (Alaska, USA, superclade E) was included in the study as well. Photosynthetic performance was measured under different controlled abiotic conditions, including dehydration and rehydration, as well as under a light and temperature gradient. All Klebsormidium strains exhibited optimum photosynthetic oxygen production at low photon fluence rates, but with no indication of photoinhibition under high light conditions pointing to flexible acclimation mechanisms of the photosynthetic apparatus. Respiration under lower temperatures was generally much less effective than photosynthesis, while the opposite was true for higher temperatures. The Klebsormidium strains tested showed a decrease and inhibition of the effective quantum yield during desiccation, however with different kinetics. While the single celled and small filamentous strains exhibited relatively fast inhibition, the uniserate filament forming isolates desiccated slower. Except one, all other strains fully recovered effective quantum yield after rehydration. The presented data provide an explanation for the regular occurrence of Klebsormidium strains or species in hot and cold deserts, which are characterized by low water availability and other stressful conditions. PMID:26422081

  18. Living in biological soil crust communities of African deserts—Physiological traits of green algal Klebsormidium species (Streptophyta) to cope with desiccation, light and temperature gradients

    PubMed Central

    Karsten, Ulf; Herburger, Klaus; Holzinger, Andreas

    2015-01-01

    Green algae of the genus Klebsormidium (Klebsormidiales, Streptophyta) are typical members of biological soil crusts (BSCs) worldwide. The phylogeny and ecophysiology of Klebsormidium has been intensively studied in recent years, and a new lineage called superclade G, which was isolated from BSCs in arid southern Africa and comprising undescribed species, was reported. Three different African strains, that have previously been isolated from hot-desert BSCs and molecular-taxonomically characterized, were comparatively investigated. In addition, Klebsormidium subtilissimum from a cold-desert habitat (Alaska, USA, superclade E) was included in the study as well. Photosynthetic performance was measured under different controlled abiotic conditions, including dehydration and rehydration, as well as under a light and temperature gradient. All Klebsormidium strains exhibited optimum photosynthetic oxygen production at low photon fluence rates, but with no indication of photoinhibition under high light conditions pointing to flexible acclimation mechanisms of the photosynthetic apparatus. Respiration under lower temperatures was generally much less effective than photosynthesis, while the opposite was true for higher temperatures. The Klebsormidium strains tested showed a decrease and inhibition of the effective quantum yield during desiccation, however with different kinetics. While the single celled and small filamentous strains exhibited relatively fast inhibition, the uniserate filament forming isolates desiccated slower. Except one, all other strains fully recovered effective quantum yield after rehydration. The presented data provide an explanation for the regular occurrence of Klebsormidium strains or species in hot and cold deserts, which are characterized by low water availability and other stressful conditions. PMID:26422081

  19. Towards developing algal synthetic biology.

    PubMed

    Scaife, Mark Aden; Smith, Alison Gail

    2016-06-15

    The genetic, physiological and metabolic diversity of microalgae has driven fundamental research into photosynthesis, flagella structure and function, and eukaryotic evolution. Within the last 10 years these organisms have also been investigated as potential biotechnology platforms, for example to produce high value compounds such as long chain polyunsaturated fatty acids, pigments and antioxidants, and for biodiesel precursors, in particular triacylglycerols (TAGs). Transformation protocols, molecular tools and genome sequences are available for a number of model species including the green alga Chlamydomonas reinhardtii and the diatom Phaeodactylum tricornutum, although for both species there are bottlenecks to be overcome to allow rapid and predictable genetic manipulation. One approach to do this would be to apply the principles of synthetic biology to microalgae, namely the cycle of Design-Build-Test, which requires more robust, predictable and high throughput methods. In this mini-review we highlight recent progress in the areas of improving transgene expression, genome editing, identification and design of standard genetic elements (parts), and the use of microfluidics to increase throughput. We suggest that combining these approaches will provide the means to establish algal synthetic biology, and that application of standard parts and workflows will avoid parallel development and capitalize on lessons learned from other systems. PMID:27284033

  20. Disturbance frequency influences patch dynamics in stream benthic algal communities.

    PubMed

    Ledger, Mark E; Harris, Rebecca M L; Armitage, Patrick D; Milner, Alexander M

    2008-04-01

    Disturbance is integral to the organisation of riverine ecosystems. Fluctuating low flows caused by supra-seasonal drought and water management periodically dewater habitat patches, potentially creating heterogeneity in the taxonomic composition and successional dynamics of benthic communities. The frequency of disturbance induced by low flows is contingent upon the topography of the river bed and thus varies among patches. We investigated whether the frequency of patch dewatering influenced the structure and temporal dynamics of benthic algal communities attached to the upper surfaces of stones in stream mesocosms (4 m2). In a 693-day disturbance experiment, we applied short dewatering disturbances (6 days) at high (33-day cycles) and low frequencies (99-day cycles) and compared algal assemblages with undisturbed controls at 21 endpoints. In the absence of disturbance, epilithic space was dominated by the green encrusting alga Gongrosira incrustans. However, drying disturbances consistently reduced the dominance of the green alga, and crust abundance decreased with increasing disturbance frequency, thereby opening space for a diversity of mat-forming diatoms. The response of mat diatoms to disturbance varied markedly during the experiment, from strong reductions in the abundance of loosely attached mats in mid-late 2000 to the exploitation of open space by closely adhering mats in 2001. Contrary responses were attributed to changes in the species composition of mat diatoms, which influenced the physiognomy and hence stress-resistance and resilience of the assemblage. Our results indicate that patchy dewatering of habitat patches during periods of low flow influences the successional dynamics of algae, thereby creating distinctive mosaics on the stream bed. PMID:18193289

  1. Sugar composition of the pectic polysaccharides of charophytes, the closest algal relatives of land-plants: presence of 3-O-methyl-d-galactose residues

    PubMed Central

    O’Rourke, Christina; Gregson, Timothy; Murray, Lorna; Sadler, Ian H.; Fry, Stephen C.

    2015-01-01

    Background and Aims During evolution, plants have acquired and/or lost diverse sugar residues as cell-wall constituents. Of particular interest are primordial cell-wall features that existed, and in some cases abruptly changed, during the momentous step whereby land-plants arose from charophytic algal ancestors. Methods Polysaccharides were extracted from four charophyte orders [Chlorokybales (Chlorokybus atmophyticus), Klebsormidiales (Klebsormidium fluitans, K. subtile), Charales (Chara vulgaris, Nitella flexilis), Coleochaetales (Coleochaete scutata)] and an early-diverging land-plant (Anthoceros agrestis). ‘Pectins’ and ‘hemicelluloses’, operationally defined as extractable in oxalate (100 °C) and 6 m NaOH (37 °C), respectively, were acid- or Driselase-hydrolysed, and the monosaccharides analysed chromatographically. One unusual monosaccharide, ‘U’, was characterized by 1H/13C-nuclear magnetic resonance spectroscopy and also enzymically. Key Results ‘U’ was identified as 3-O-methyl-d-galactose (3-MeGal). All pectins, except in Klebsormidium, contained acid- and Driselase-releasable galacturonate, suggesting homogalacturonan. All pectins, without exception, released rhamnose and galactose on acid hydrolysis; however, only in ‘higher’ charophytes (Charales, Coleochaetales) and Anthoceros were these sugars also efficiently released by Driselase, suggesting rhamnogalacturonan-I. Pectins of ‘higher’ charophytes, especially Chara, contained little arabinose, instead possessing 3-MeGal. Anthoceros hemicelluloses were rich in glucose, xylose, galactose and arabinose (suggesting xyloglucan and arabinoxylan), none of which was consistently present in charophyte hemicelluloses. Conclusions Homogalacturonan is an ancient streptophyte feature, albeit secondarily lost in Klebsormidium. When conquering the land, the first embryophytes already possessed rhamnogalacturonan-I. In contrast, charophyte and land-plant hemicelluloses differ

  2. Lipids of recently-deposited algal mats at Laguna Mormona, Baja California

    NASA Technical Reports Server (NTRS)

    Cardoso, J.; Brooks, P. W.; Eglinton, G.; Goodfellow, R.; Maxwell, J. R.; Philp, R. P.

    1976-01-01

    A preliminary survey of the lipid composition of the core of a recently deposited algal mat of a subtropical, hypersaline coastal pond is described. Two layers of the core were examined: the upper, 2-cm-thick layer, comprising the fresh algal mat of predominantly the blue-green species Microcoleus chthonoplastes, and the black anaerobic algal ooze at a depth of 10 cm. About 75% of the n-alkanes in the mat were accounted for by n-C17, with smaller amounts of higher homologues maximizing at n-C27. The ooze was characterized by a bimodal distribution with maxima at n-C17 and n-C27. The n-alkanoic acids distributions were similar to the corresponding n-alkane distributions. A marked decrease in the ratio of monounsaturated to saturated acids in the ooze relative to the mat was observed, which indicates a preferential removal of unsaturated components. Certain triterpenes of the hopane skeletal type were present in the mat and ooze. The presence of stanols and sterenes in the ooze with similar carbon number distributions suggests a relationship between them.

  3. Presence of the CO2-concentrating mechanism in some species of the pyrenoid-less free-living algal genus Chloromonas (Volvocales, Chlorophyta).

    PubMed

    Morita, E; Abe, T; Tsuzuki, M; Fujiwara, S; Sato, N; Hirata, A; Sonoike, K; Nozaki, H

    1998-03-01

    Physiological and morphological characteristics related to the CO2-concentrating mechanism (CCM) were examined in several species of the free-living, unicellular volvocalean genus Chloromonas (Chlorophyta), which differs morphologically from the genus Chlamydomonas only by lacking pyrenoids. The absence of pyrenoids in the chloroplasts of Chloromonas (Cr.) rosae UTEX 1337, Cr. serbinowii UTEX 492, Cr. clatharata UTEX 1970, Cr. rosae SAG 26.90, and Cr. palmelloides SAG 32.86 was confirmed by light and electron microscopy. In addition, immunogold electron microscopy demonstrated that ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) molecules were distributed almost evently throughout the chloroplasts in all five Chloromonas strains. However, Chloromonas exhibited two types of physiological characteristics related to the CCM depending on the species or strains examined. Chloromonas rosae UTEX 1337 and Cr. serbinowii had high photosynthetic affinities for CO2 in cells grown in culture medium bubbled with air (low-CO2 cells), compared with those grown in medium bubbled with 5% CO2 (high-CO2 cells), indicating the presence of the low-CO2-inducible CCM. In addition, these two Chloromonas strains exhibited low-CO2-inducible carbonic anhydrase (CA; EC 4.2.1.1) activity and seemed to have small intracellular inorganic carbon pools. Therefore, it appears that Cr. rosae UTEX 1337 and Cr. serbinowii possess the CCM as in pyrenoid-containing microalgae such as Chlamydomonas reinhardtii. By contrast, Cr. clatharata, Cr. rosae SAG 26.90 and Cr. palmelloides showed low photosynthetic affinities for CO2 when grown under both CO2 conditions. Moreover, these three strains exhibited an apparent absence of intracellular inorganic carbon pools and lacked low-CO2-inducible CA activity. Thus, Cr. clatharata, Cr. rosae SAG 26.90 and Cr. palmelloides, like other pyrenoid-less algae (lichen photobionts) reported previously, seem to lack the CCM. The present study is the

  4. Addressing the challenges for sustainable production of algal biofuels: I. Algal strains and nutrient supply.

    PubMed

    Abdelaziz, Ahmed E M; Leite, Gustavo B; Hallenbeck, Patrick C

    2013-01-01

    Microalgae hold promise for the production of sustainable replacement of fossil fuels due to their high growth rates, ability to grow on non-arable land and their high content, under the proper conditions, of high energy compounds that can be relatively easily chemically converted to fuels using existing technology. However, projected large-scale algal production raises a number of sustainability concerns concerning land use, net energy return, water use and nutrient supply. The state-of-the-art of algal production of biofuels is presented with emphasis on some possible avenues to provide answers to the sustainability questions that have been raised. Here, issues concerning algal strains and supply of nutrients for large-scale production are discussed. Since sustainability concerns necessitate the use of wastewaters for supply of bulk nutrients, emphasis is placed on the composition and suitability of different wastewater streams. At the same time, algal cultivation has proven useful in waste treatment processes, and thus this aspect is also treated in some detail. PMID:24350435

  5. Does mechanical disturbance affect the performance and species composition of submerged macrophyte communities?

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Xu, Ying-Shou; Huang, Lin; Xue, Wei; Sun, Gong-Qi; Zhang, Ming-Xiang; Yu, Fei-Hai

    2014-05-01

    Submerged macrophyte communities are frequently subjected to disturbance of various frequency and strength. However, there is still little experimental evidence on how mechanical disturbance affects the performance and species composition of such plant communities. In a greenhouse experiment, we constructed wetland communities consisting of five co-occurring clonal submerged macrophyte species (Hydrilla verticillata, Elodea canadensis, Ceratophyllum demersum, Chara fragilis, and Myriophyllum spicatum) and subjected these communities to three mechanical disturbance regimes (no, moderate and strong disturbance). Strong mechanical disturbance greatly decreased overall biomass, number of shoot nodes and total shoot length, and increased species diversity (evenness) of the total community. It also substantially decreased the growth of the most abundant species (H. verticillata), but did not affect growth of the other four species. Our data reveal that strong disturbance can have different effects on different submerged macrophyte species and thus alters the performance and species composition of submerged macrophyte communities.

  6. Does mechanical disturbance affect the performance and species composition of submerged macrophyte communities?

    PubMed

    Zhang, Qian; Xu, Ying-Shou; Huang, Lin; Xue, Wei; Sun, Gong-Qi; Zhang, Ming-Xiang; Yu, Fei-Hai

    2014-01-01

    Submerged macrophyte communities are frequently subjected to disturbance of various frequency and strength. However, there is still little experimental evidence on how mechanical disturbance affects the performance and species composition of such plant communities. In a greenhouse experiment, we constructed wetland communities consisting of five co-occurring clonal submerged macrophyte species (Hydrilla verticillata, Elodea canadensis, Ceratophyllum demersum, Chara fragilis, and Myriophyllum spicatum) and subjected these communities to three mechanical disturbance regimes (no, moderate and strong disturbance). Strong mechanical disturbance greatly decreased overall biomass, number of shoot nodes and total shoot length, and increased species diversity (evenness) of the total community. It also substantially decreased the growth of the most abundant species (H. verticillata), but did not affect growth of the other four species. Our data reveal that strong disturbance can have different effects on different submerged macrophyte species and thus alters the performance and species composition of submerged macrophyte communities. PMID:24811826

  7. Composition of Residue from Sugarcane and Related Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Louisiana, a facility near Jennings will produce cellulosic ethanol from sugarcane (Saccharum spp. hybrids) bagasse and “energy canes”. This study was done to obtain basic information on the composition of the cell wall residue left after expressing the juice in different Saccharum genotypes. Fou...

  8. The ins and outs of algal metal transport

    PubMed Central

    Blaby-Haas, Crysten E.; Merchant, Sabeeha S.

    2012-01-01

    Metal transporters are a central component in the interaction of algae with their environment. They represent the first line of defense to cellular perturbations in metal concentration, and by analyzing algal metal transporter repertoires, we gain insight into a fundamental aspect of algal biology. The ability of individual algae to thrive in environments with unique geochemistry, compared to non-algal species commonly used as reference organisms for metal homeostasis, provides an opportunity to broaden our understanding of biological metal requirements, preferences and trafficking. Chlamydomonas reinhardtii is the best developed reference organism for the study of algal biology, especially with respect to metal metabolism; however, the diversity of algal niches necessitates a comparative genomic analysis of all sequenced algal genomes. A comparison between known and putative proteins in animals, plants, fungi and algae using protein similarity networks has revealed the presence of novel metal metabolism components in Chlamydomonas including new iron and copper transporters. This analysis also supports the concept that, in terms of metal metabolism, algae from similar niches are more related to one another than to algae from the same phylogenetic clade. PMID:22569643

  9. NECTAR COMPOSITION OF WILD PERENNIAL GLYCINE (SOYBEAN) SPECIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Glycine contains the cultivated annual soybean G. max, the wild annual, G. soja, and about 21 wild perennial Glycine species. The perennials are largely indigenous to Australia, but are found in Papua New Guinea, Timor, Philippines, Japan and Taiwan. Outcrossing rates in the cultivated s...

  10. Algal functional annotation tool

    SciTech Connect

    Lopez, D.; Casero, D.; Cokus, S. J.; Merchant, S. S.; Pellegrini, M.

    2012-07-01

    The Algal Functional Annotation Tool is a web-based comprehensive analysis suite integrating annotation data from several pathway, ontology, and protein family databases. The current version provides annotation for the model alga Chlamydomonas reinhardtii, and in the future will include additional genomes. The site allows users to interpret large gene lists by identifying associated functional terms, and their enrichment. Additionally, expression data for several experimental conditions were compiled and analyzed to provide an expression-based enrichment search. A tool to search for functionally-related genes based on gene expression across these conditions is also provided. Other features include dynamic visualization of genes on KEGG pathway maps and batch gene identifier conversion.

  11. Algal Culture Material

    ERIC Educational Resources Information Center

    Baldock, R.

    1971-01-01

    Suggests suitable species of microscopic green algae for demonstrating diversity of form, increasing complexity in related species, the animal" and plant" characteristics of protists, and protist behavior. (AL)

  12. Seasonal variations of epipelic algal community in relation to environmental factors in the Istanbul Strait (the Bosphorus), Turkey.

    PubMed

    Aktan, Y; Balkıs, N; Balkıs, N

    2014-04-15

    This study was implemented to investigate the species composition, abundance, seasonal variations and diversity of epipelic algae, to determine environmental variables affecting them and to reveal the accumulation of total organic carbon in the sediment in the coastal zone of the Istanbul Strait, Turkey. Epipelic algal community consisted of 44 taxa with a low diversity. The sediment structure which is highly unstable due to the high hydrodynamism of the zone played a dominant role as the main factor in the epipelic algal flora along the coasts of Istanbul Strait. Low TOC and high carbonate values also support this result. The dominance of cyanobacteria in some periods and, as a result of this, the record of the lowest diversity index values indicated the effect of nutrient enrichment and the risk of coastal eutrophication. High dominance of cyanobacteria may also be explicated by climate changes considering its effect in the other areas. PMID:24467854

  13. Species composition and abundance of Brevipalpus spp. on different citrus species in Mexican orchards.

    PubMed

    Salinas-Vargas, D; Santillán-Galicia, M T; Valdez-Carrasco, J; Mora-Aguilera, G; Atanacio-Serrano, Y; Romero-Pescador, P

    2013-08-01

    We studied the abundance of Brevipalpus spp. in citrus orchards in the Mexican states of Yucatan, Quintana Roo and Campeche. Mites were collected from 100 trees containing a mixture of citrus species where sweet orange was always the main species. Eight collections were made at each location from February 2010 to February 2011. Mites from the genus Brevipalpus were separated from other mites surveyed and their abundance and relationships with the different citrus species were quantified throughout the collection period. A subsample of 25% of the total Brevipalpus mites collected were identified to species level and the interaction of mite species and citrus species were described. Brevipalpus spp. were present on all collection dates and their relative abundance was similar on all citrus species studies. The smallest number of mites collected was during the rainy season. Brevipalpus phoenicis (Geijskes) and Brevipalpus californicus (Banks) were the only two species present and they were found in all locations except Campeche, where only B. phoenicis was present. Yucatan and Campeche are at greater risk of leprosis virus transmission than Quintana Roo because the main vector, B. phoenicis, was more abundant than B. californicus. The implications of our results for the design of more accurate sampling and control methods for Brevipalpus spp. are discussed. PMID:23949863

  14. Species composition, toxigenic potential and pathogenicity of Fusarium graminearum species complex isolates from southern Brazilian rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study aimed to assess the extent and distribution of Fusarium graminearum species complex (FGSC) diversity in Brazilian rice. Four species and two trichothecene genotypes were found among 89 FGSC isolates obtained from infected seeds: F. asiaticum with the nivalenol (NIV) genotype (69%), F. gra...

  15. Enantiomeric composition studies in Lavandula species using supercritical fluids.

    PubMed

    Flores, Gema; Blanch, Gracia Patricia; Ruiz del Castillo, Maria Luisa; Herraiz, Marta

    2005-11-01

    Characteristic aroma compounds in plants and essential oils of Lavandula from different varieties were examined. The study of the qualitative and quantitative composition of the major volatile components was faced by developing a method based on the use of supercritical fluid extraction-GC-MS (SFE-GC-MS). The optimization of a variety of parameters affecting SFE extraction enabled RSDs from three replicates lower than 2% to be achieved. Equally, recoveries of up to 59% were obtained by applying the proposed method. The use of multidimensional GC was necessary to enantiomerically resolve the target compounds. The obtained results showed enantiomeric purities >90% for all studied compounds in all varieties considered, proving the natural invariability of the enantiomeric composition of the compounds of interest. This information can be useful in authenticity studies as well as in selecting natural sources of enantiomerically pure compounds. PMID:16342799

  16. Nectar Concentration and Composition of 26 Species from the Temperate Forest of South America

    PubMed Central

    CHALCOFF, VANINA R.; AIZEN, MARCELO A.; GALETTO, LEONARDO

    2006-01-01

    • Background and Aims Floral nectar concentration and chemical composition of 26 plant species native to the temperate forest of southern South America are reported and the relationships with the flower type are evaluated. • Methods Nectar concentration was measured with a hand refractometer and sugar composition was analysed by gas–liquid chromatography. Plant species were classified into flower type categories based not only on floral features but also on data from the literature and field observations on their pollinators. • Key Results Most data on nectar are new reports at the generic and/or specific level. Plant species in which more than one population was studied showed significant among-population variation in nectar sugar concentration and composition. Results showed a weak relationship between nectar traits and flower type. Many species had nectar containing 50 % or more sucrose (17 of 26 species), independent of the main pollinator. • Conclusions Considering that (a) nectar characteristics did not show a clear association with different flower types or with plant taxonomic membership, and (b) different populations of the same species showed large variability in sugar composition, the results suggest that other factors (e.g. historical and environmental) could be involved in determining the sugar composition of the highly endemic plant species from this region. PMID:16373370

  17. Food resource use by two territorial damselfish (Pomacentridae: Stegastes) on South-Western Atlantic algal-dominated reefs

    NASA Astrophysics Data System (ADS)

    Feitosa, João Lucas L.; Concentino, Adilma M.; Teixeira, Simone F.; Ferreira, Beatrice P.

    2012-05-01

    Damselfishes are a highly abundant group of reef fishes that are considered keystone species for structuring benthic communities on coral-dominated reefs. To assess how food is utilized by the damselfish species Stegastes fuscus and Stegastes variabilis living on algae-dominated coastal reefs, we evaluated the compositions of algal communities inside their territories and investigated their diets by analyzing their stomach contents. Jointed-calcareous algae were the most abundant morphological group inside the territories of both damselfish species (> 80%), and the biomass of these algae showed a positive linear relationship to all the other non-calcareous algae when grouped together (R² = 0.674; p < 0.001), suggesting that the former exerts a positive influence on the biomasses of species of non-calcareous algae by creating surfaces on which they can grow. Most of the diet of Stegastes spp. consisted of algal material (> 70%), but they also fed on invertebrates and detritus as accessory items (~ 15%). Algal material composed a consistent proportion of the items ingested by adults and juveniles of both damselfish species with diatoms being the most frequent item, followed by filamentous algae. A positive food selection for all macroalgae morphological groups was observed, except for jointed-calcareous algae (Ivlev's index). The most preferred macroalgae types were filamentous, with values close to + 1 for both damselfish species. Pianka's food overlap index was extremely high regardless of the damselfish species or their life phase and ANOSIM analyses also confirmed that there were essentially no differences between their diets. The present work is the first indication that damselfish may maintain territories dominated by highly unpalatable calcareous macroalgae that have herbivore-deterrent life strategies, although the complex branching structures of these macroalgae create suitable microhabitats for the growth of epiphytic species consumed by the damselfish.

  18. Algal Biofuels; Algal Biofuels R&D at NREL (Brochure)

    SciTech Connect

    Not Available

    2010-09-01

    An overview of NREL's algal biofuels projects, including U.S. Department of Energy-funded work, projects with U.S. and international partners, and Laboratory Directed Research and Development projects.

  19. Species composition of Malassezia yeasts in dogs in Slovakia.

    PubMed

    Sihelská, Zuzana; Váczi, Peter; Conková, Eva

    2016-01-01

    Malassezia (M.) pachydermatis is the lipophilic yeast, which is normally present on the skin and in the ear canal of dogs but under certain conditions it may cause dermatitis and otitis. There is less known about the occurrence of lipid-dependent Malassezia species in dogs. The aim of this study was to detect whether lipid-dependent yeasts are part of the normal microflora in dogs. Two groups of animals were selected for comparison. The group of healthy dogs contained samples of 118 individuals and the group of dogs with cutaneous lesions or otitis externa comprised 328 dogs. The isolates of Malassezia were identified by using genotypic methods that allow the precise identification. M. pachydermatis was the most frequently isolated species in this study (121 isolates). Only four isolates were identified as M. furfur and one isolate was identified as M. nana. PMID:27529998

  20. Polyphenolic composition and content in the ripe berries of wild Vitis species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To explore wild genetic resources for improving fruit and processing quality of cultivated grape cultivars, we characterized the polyphenolic composition and content in the ripe berries of 147 grape accessions from 16 Vitis species for two consecutive years. These species, except for Vitis Yenshansi...

  1. The megaepifauna of the Dogger Bank (North Sea): species composition and faunal characteristics 1991-2008

    NASA Astrophysics Data System (ADS)

    Sonnewald, Moritz; Türkay, Michael

    2012-03-01

    During a long-term study in the summer months of the years 1991-2008, 176 megaepifaunal species were recorded through a series of beam trawl surveys on a grid of fixed stations on the Dogger Bank (central North Sea). This paper gives a qualitative overview on species composition throughout the research period, determined from samples collected during 15 cruises. In recent years, a number of species with more oceanic distribution patterns (e.g. species from SW British coasts) has been collected. In spite of these newcomers, there was a slight decrease in total species numbers during the research period.

  2. Host species composition influences infection severity among amphibians in the absence of spillover transmission.

    PubMed

    Han, Barbara A; Kerby, Jacob L; Searle, Catherine L; Storfer, Andrew; Blaustein, Andrew R

    2015-04-01

    Wildlife epidemiological outcomes can depend strongly on the composition of an ecological community, particularly when multiple host species are affected by the same pathogen. However, the relationship between host species richness and disease risk can vary with community context and with the degree of spillover transmission that occurs among co-occurring host species. We examined the degree to which host species composition influences infection by Batrachochytrium dendrobatidis (Bd), a widespread fungal pathogen associated with amphibian population declines around the world, and whether transmission occurs from one highly susceptible host species to other co-occurring host species. By manipulating larval assemblages of three sympatric amphibian species in the laboratory, we characterized the relationship between host species richness and infection severity, whether infection mediates growth and survivorship differently across various combinations of host species, and whether Bd is transmitted from experimentally inoculated tadpoles to uninfected tadpoles. We found evidence of a dilution effect where Bd infection severity was dramatically reduced in the most susceptible of the three host species (Anaxyrus boreas). Infection also mediated survival and growth of all three host species such that the presence of multiple host species had both positive (e.g., infection reduction) and negative (e.g., mortality) effects on focal species. However, we found no evidence that Bd infection is transmitted by this species. While these results demonstrate that host species richness as well as species identity underpin infection dynamics in this system, dilution is not the product of reduced transmission via fewer infectious individuals of a susceptible host species. We discuss various mechanisms, including encounter reduction and antagonistic interactions such as competition and opportunistic cannibalism that may act in concert to mediate patterns of infection severity, growth

  3. Host species composition influences infection severity among amphibians in the absence of spillover transmission

    PubMed Central

    Han, Barbara A; Kerby, Jacob L; Searle, Catherine L; Storfer, Andrew; Blaustein, Andrew R

    2015-01-01

    Wildlife epidemiological outcomes can depend strongly on the composition of an ecological community, particularly when multiple host species are affected by the same pathogen. However, the relationship between host species richness and disease risk can vary with community context and with the degree of spillover transmission that occurs among co-occurring host species. We examined the degree to which host species composition influences infection by Batrachochytrium dendrobatidis (Bd), a widespread fungal pathogen associated with amphibian population declines around the world, and whether transmission occurs from one highly susceptible host species to other co-occurring host species. By manipulating larval assemblages of three sympatric amphibian species in the laboratory, we characterized the relationship between host species richness and infection severity, whether infection mediates growth and survivorship differently across various combinations of host species, and whether Bd is transmitted from experimentally inoculated tadpoles to uninfected tadpoles. We found evidence of a dilution effect where Bd infection severity was dramatically reduced in the most susceptible of the three host species (Anaxyrus boreas). Infection also mediated survival and growth of all three host species such that the presence of multiple host species had both positive (e.g., infection reduction) and negative (e.g., mortality) effects on focal species. However, we found no evidence that Bd infection is transmitted by this species. While these results demonstrate that host species richness as well as species identity underpin infection dynamics in this system, dilution is not the product of reduced transmission via fewer infectious individuals of a susceptible host species. We discuss various mechanisms, including encounter reduction and antagonistic interactions such as competition and opportunistic cannibalism that may act in concert to mediate patterns of infection severity, growth

  4. DNA Barcoding of Shark Meats Identify Species Composition and CITES-Listed Species from the Markets in Taiwan

    PubMed Central

    Liu, Shang-Yin Vanson; Chan, Chia-Ling Carynn; Lin, Oceana; Hu, Chieh-Shen; Chen, Chaolun Allen

    2013-01-01

    Background An increasing awareness of the vulnerability of sharks to exploitation by shark finning has contributed to a growing concern about an unsustainable shark fishery. Taiwan’s fleet has the 4th largest shark catch in the world, accounting for almost 6% of the global figures. Revealing the diversity of sharks consumed by Taiwanese is important in designing conservation plans. However, fins make up less than 5% of the total body weight of a shark, and their bodies are sold as filets in the market, making it difficult or impossible to identify species using morphological traits. Methods In the present study, we adopted a DNA barcoding technique using a 391-bp fragment of the mitochondrial cytochrome oxidase I (COI) gene to examine the diversity of shark filets and fins collected from markets and restaurants island-wide in Taiwan. Results Amongst the 548 tissue samples collected and sequenced, 20 major clusters were apparent by phylogenetic analyses, each of them containing individuals belonging to the same species (most with more than 95% bootstrap values), corresponding to 20 species of sharks. Additionally, Alopias pelagicus, Carcharhinus falciformis, Isurus oxyrinchus, and Prionace glauca consisted of 80% of the samples we collected, indicating that these species might be heavily consumed in Taiwan. Approximately 5% of the tissue samples used in this study were identified as species listed in CITES Appendix II, including two species of Sphyrna, C. longimanus and Carcharodon carcharias. Conclusion DNA barcoding provides an alternative method for understanding shark species composition when species-specific data is unavailable. Considering the global population decline, stock assessments of Appendix II species and highly consumed species are needed to accomplish the ultimate goal of shark conservation. PMID:24260209

  5. Biochemical composition of three species of unionid mussels after emersion

    USGS Publications Warehouse

    Greseth, Shari L.; Cope, W.G.; Rada, R.G.; Waller, D.L.; Bartsch, M.R.

    2003-01-01

    Freshwater mussels are emersed (exposed to air) during conservation activities such as surveys and relocations. Success of these activities depends upon the ability of mussels to survive emersion and to re-burrow in the substratum. We evaluated the acute sublethal effects of emersion on three species of unionid mussels [pocketbook, Lampsilis cardium (Rafinesque, 1820); pimpleback, Quadrula pustulosa pustulosa (I. Lea, 1831); spike, Elliptio dilatata (Rafinesque, 1820)] by measuring three biochemicals (carbohydrate, lipid, protein) indicative of biochemical function and energy storage. Mussels were acclimated in water at 25??C and exposed to five air temperatures (15, 20, 25, 35 and 45??C) for 15, 30 and 60 min. After emersion, mussels were returned to water at 25??C and observed for 14 days. Samples of mantle tissue were taken after the 14-day postexposure period and analysed for carbohydrate, lipid and protein. Three-way analysis of variance (ANOVA) did not reveal consistent trends in carbohydrate, lipid or protein concentrations due to sex of mussels, duration of emersion, air temperature or their interaction terms that indicated biological compensation to stress. Overall mean carbohydrate concentrations were greatest (range 447-615 mg/g dry wt) among the species, followed by protein (179-289 mg/g dry wt) and lipids (26.7-38.1 mg/g dry wt). These results have positive implications for conducting conservation activities, because emersion over the range of temperatures (15-35??C) and durations (15-60 min) examined did not appear acutely harmful to mussels.

  6. Explaining the effects of floral density on flower visitor species composition.

    PubMed

    Essenberg, Carla J

    2013-03-01

    Floral density often influences the species composition of flower visitors. This variation in visitor species composition could have significant effects on pollination success and plant fitness but is poorly understood, especially in the many pollination guilds dominated by nonterritorial species. This article presents a foraging model that explores how flower visitors with diverse traits should distribute themselves across resource patches differing in floral density. The model predicts that species with low flower search speeds and low flower handling costs compared to those of competitors will usually dominate dense flower patches. In addition, among flower visitors that have lower energy expenditure rates while handling flowers than while traveling, species maximizing energetic efficiency are typically associated with dense flower patches, whereas those maximizing net rate of energy intake are associated with sparse patches. The model is able to predict some key aspects of a previously observed effect of floral density on species composition of flower visitors to the yellowflower tarweed (Holocarpha virgata). By providing insights into how flower visitors' traits shape the effects of floral density on the species composition of flower visitors, this study makes an important step towards understanding how pollinator diversity influences relationships between plant density and plant fitness. PMID:23448884

  7. Wood Chemical Composition in Species of Cactaceae: The Relationship between Lignification and Stem Morphology

    PubMed Central

    Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos

    2015-01-01

    In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level. PMID:25880223

  8. Species richness effects on ecosystem multifunctionality depend on evenness, composition and spatial pattern

    USGS Publications Warehouse

    Maestre, F.T.; Castillo-Monroy, A. P.; Bowker, M.A.; Ochoa-Hueso, R.

    2012-01-01

    1. Recent studies have suggested that the simultaneous maintenance of multiple ecosystem functions (multifunctionality) is positively supported by species richness. However, little is known regarding the relative importance of other community attributes (e.g. spatial pattern, species evenness) as drivers of multifunctionality. 2. We conducted two microcosm experiments using model biological soil crust communities dominated by lichens to: (i) evaluate the joint effects and relative importance of changes in species composition, spatial pattern (clumped and random distribution of lichens), evenness (maximal and low evenness) and richness (from two to eight species) on soil functions related to nutrient cycling (β-glucosidase, urease and acid phosphatase enzymes, in situ N availability, total N, organic C, and N fixation), and (ii) assess how these community attributes affect multifunctionality. 3. Species richness, composition and spatial pattern affected multiple ecosystem functions (e.g. organic C, total N, N availability, β-glucosidase activity), albeit the magnitude and direction of their effects varied with the particular function, experiment and soil depth considered. Changes in species composition had effects on organic C, total N and the activity of β-glucosidase. Significant species richness × evenness and spatial pattern × evenness interactions were found when analysing functions such as organic C, total N and the activity of phosphatase. 4. The probability of sustaining multiple ecosystem functions increased with species richness, but this effect was largely modulated by attributes such as species evenness, composition and spatial pattern. Overall, we found that model communities with high species richness, random spatial pattern and low evenness increased multifunctionality. 5. Synthesis. Our results illustrate how different community attributes have a diverse impact on ecosystem functions related to nutrient cycling, and provide new

  9. Fueling Future with Algal Genomics

    SciTech Connect

    Grigoriev, Igor

    2012-07-05

    Algae constitute a major component of fundamental eukaryotic diversity, play profound roles in the carbon cycle, and are prominent candidates for biofuel production. The US Department of Energy Joint Genome Institute (JGI) is leading the world in algal genome sequencing (http://jgi.doe.gov/Algae) and contributes of the algal genome projects worldwide (GOLD database, 2012). The sequenced algal genomes offer catalogs of genes, networks, and pathways. The sequenced first of its kind genomes of a haptophyte E.huxleyii, chlorarachniophyte B.natans, and cryptophyte G.theta fill the gaps in the eukaryotic tree of life and carry unique genes and pathways as well as molecular fossils of secondary endosymbiosis. Natural adaptation to conditions critical for industrial production is encoded in algal genomes, for example, growth of A.anophagefferens at very high cell densities during the harmful algae blooms or a global distribution across diverse environments of E.huxleyii, able to live on sparse nutrients due to its expanded pan-genome. Communications and signaling pathways can be derived from simple symbiotic systems like lichens or complex marine algae metagenomes. Collectively these datasets derived from algal genomics contribute to building a comprehensive parts list essential for algal biofuel development.

  10. Interactions of multiwalled carbon nanotubes with algal cells: quantification of association, visualization of uptake, and measurement of alterations in the composition of cells.

    PubMed

    Rhiem, Stefan; Riding, Matthew J; Baumgartner, Werner; Martin, Francis L; Semple, Kirk T; Jones, Kevin C; Schäffer, Andreas; Maes, Hanna M

    2015-01-01

    Carbon nanotubes (CNTs) are considered promising materials in nanotechnology. We quantified CNT accumulation by the alga Desmodesmus subspicatus. Cells were exposed to radiolabeled CNTs ((14)C-CNTs;1 mg/L) to determine uptake and association, as well as elimination and dissociation in clear media.Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) was used to detect effects of CNTs on algae. CNT-cell interactions were visualized by electron microscopy and related to alterations in their cell composition. A concentration factor of 5000 L/kg dry weight was calculated. Most of the material agglomerated around the cells, but single tubes were detected in the cytoplasm. Computational analyses of the ATR-FTIR data showed that CNT treated algae differed from controls at all sampling times.CNT exposure changed the biochemical composition of cells. The fact that CNTs are bioavailable for algae and that they influence the cell composition is important with regard to environmental risk assessment of this nanomaterial. PMID:25467692

  11. Fatty acid and sterol composition of three phytomonas species.

    PubMed

    Nakamura, C V; Waldow, L; Pelegrinello, S R; Ueda-Nakamura, T; Filho, B A; Filho, B P

    1999-01-01

    Fatty acid and sterol analysis were performed on Phytomonas serpens and Phytomonas sp. grown in chemically defined and complex medium, and P. françai cultivated in complex medium. The three species of the genus Phytomonas had qualitatively identical fatty acid patterns. Oleic, linoleic, and linolenic were the major unsaturated fatty acids. Miristic and stearic were the major saturated fatty acids. Ergosterol was the only sterol isolated from Phytmonas sp. and P. serpens grown in a sterol-free medium, indicating that it was synthesized de novo. When P. françai that does not grow in defined medium was cultivated in a complex medium, cholesterol was the only sterol detected. The fatty acids and sterol isolated from Phytomonas sp. and P. serpens grown in a chemically defined lipid-free medium indicated that they were able to biosynthesize fatty acids and ergosterol from acetate or from acetate precursors such as glucose or threonine. PMID:10446013

  12. Biochemical composition of three species of unionid mussels after emersion

    USGS Publications Warehouse

    Greseth, Shari L.; Cope, W.G.; Rada, R.G.; Waller, D.L.; Bartsch, M.R.

    2003-01-01

    Freshwater mussels are emersed (exposed to air) during conservation activities such as surveys and relocations. Success of these activities depends upon the ability of mussels to survive emersion and to re-burrow in the substratum. We evaluated the acute sublethal effects of emersion on three species of unionid mussels [pocketbook, Lampsilis cardium (Rafinesque, 1820); pimpleback, Quadrula pustulosa pustulosa (I. Lea, 1831); spike, Elliptio dilatata (Rafinesque, 1820)] by measuring three biochemicals (carbohydrate, lipid, protein) indicative of biochemical function and energy storage. Mussels were acclimated in water at 25A?C and exposed to five air temperatures (15, 20, 25, 35 and 45A?C) for 15, 30 and 60 min. After emersion, mussels were returned to water at 25A?C and observed for 14 days. Samples of mantle tissue were taken after the 14-day postexposure period and analysed for carbohydrate, lipid and protein. Three-way analysis of variance (ANOVA) did not reveal consistent trends in carbohydrate, lipid or protein concentrations due to sex of mussels, duration of emersion, air temperature or their interaction terms that indicated biological compensation to stress. Overall mean carbohydrate concentrations were greatest (range 447a??615 mg/g dry wt) among the species, followed by protein (179a??289 mg/g dry wt) and lipids (26.7a??38.1 mg/g dry wt). These results have positive implications for conducting conservation activities, because emersion over the range of temperatures (15a??35A?C) and durations (15a??60 min) examined did not appear acutely harmful to mussels.

  13. Remnant Trees Affect Species Composition but Not Structure of Tropical Second-Growth Forest

    PubMed Central

    Sandor, Manette E.; Chazdon, Robin L.

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2–3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests (“control plots”). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields. PMID:24454700

  14. Effects of Previous Land-Use on Plant Species Composition and Diversity in Mediterranean Forests.

    PubMed

    Kouba, Yacine; Martínez-García, Felipe; de Frutos, Ángel; Alados, Concepción L

    2015-01-01

    At some point in their history, most forests in the Mediterranean Basin have been subjected to intensive management or converted to agriculture land. Knowing how forest plant communities recovered after the abandonment of forest-management or agricultural practices (including livestock grazing) provides a basis for investigating how previous land management have affected plant species diversity and composition in forest ecosystems. Our study investigated the consequences of historical "land management" practices on present-day Mediterranean forests by comparing species assemblages and the diversity of (i) all plant species and (ii) each ecological group defined by species' habitat preferences and successional status (i.e., early-, mid-, and late-successional species). We compared forest stands that differed both in land-use history and in successional stage. In addition, we evaluated the value of those stands for biodiversity conservation. The study revealed significant compositional differentiation among stands that was due to among-stand variations in the diversity (namely, species richness and evenness) of early-, intermediate-, and late-successional species. Historical land management has led to an increase in compositional divergences among forest stands and the loss of late-successional forest species. PMID:26397707

  15. Detection of surface algal blooms using the newly developed algorithm surface algal bloom index (SABI)

    NASA Astrophysics Data System (ADS)

    Alawadi, Fahad

    2010-10-01

    Quantifying ocean colour properties has evolved over the past two decades from being able to merely detect their biological activity to the ability to estimate chlorophyll concentration using optical satellite sensors like MODIS and MERIS. The production of chlorophyll spatial distribution maps is a good indicator of plankton biomass (primary production) and is useful for the tracing of oceanographic currents, jets and blooms, including harmful algal blooms (HABs). Depending on the type of HABs involved and the environmental conditions, if their concentration rises above a critical threshold, it can impact the flora and fauna of the aquatic habitat through the introduction of the so called "red tide" phenomenon. The estimation of chlorophyll concentration is derived from quantifying the spectral relationship between the blue and the green bands reflected from the water column. This spectral relationship is employed in the standard ocean colour chlorophyll-a (Chlor-a) product, but is incapable of detecting certain macro-algal species that float near to or at the water surface in the form of dense filaments or mats. The ability to accurately identify algal formations that sometimes appear as oil spill look-alikes in satellite imagery, contributes towards the reduction of false-positive incidents arising from oil spill monitoring operations. Such algal formations that occur in relatively high concentrations may experience, as in land vegetation, what is known as the "red-edge" effect. This phenomena occurs at the highest reflectance slope between the maximum absorption in the red due to the surrounding ocean water and the maximum reflectance in the infra-red due to the photosynthetic pigments present in the surface algae. A new algorithm termed the surface algal bloom index (SABI), has been proposed to delineate the spatial distributions of floating micro-algal species like for example cyanobacteria or exposed inter-tidal vegetation like seagrass. This algorithm was

  16. Genetic and acute toxicological evaluation of an algal oil containing eicosapentaenoic acid (EPA) and palmitoleic acid.

    PubMed

    Collins, M L; Lynch, B; Barfield, W; Bull, A; Ryan, A S; Astwood, J D

    2014-10-01

    Algal strains of Nannochloropsis sp. were developed, optimized, cultivated and harvested to produce a unique composition of algal oil ethyl esters (Algal-EE) that are naturally high in eicosapentaenoic acid (EPA, 23-30%) and palmitoleic acid (20-25%), and contain no docosahexaenoic acid (DHA). Algal-EE was evaluated for mutagenic activity (Ames bacterial reverse mutation, in vitro mammalian chromosome aberration, in vivo micronucleus test) and for acute oral toxicity in Sprague-Dawley rats. In the acute toxicity study, rats received a single oral gavaged dose of Algal-EE (2000 mg/kg body weight). Clinical observations were made for 14 days before sacrifice on Day 15. Macroscopic evaluation involved the examination of all organs in the cranial, thoracic, and abdominal cavities. Algal-EE showed no evidence of mutagenicity, did not produce an increase in the frequency of structural chromosome aberrations, and did not cause an increase in the induction of micronucleated polychromatic erythrocytes. There were no macroscopic abnormalities. Algal-EE up to 2000 mg/kg body weight did not affect body weight, organ appearance or produce any toxic-related signs of morbidity. The acute median lethal dose (LD50) of Algal-EE was >2000 mg/kg body weight. Based on these assays, Algal-EE does not appear to have any genetic or acute oral toxicity. PMID:25057807

  17. The effect of AMF suppression on plant species composition in a nutrient-poor dry grassland.

    PubMed

    Dostálek, Tomáš; Pánková, Hana; Münzbergová, Zuzana; Rydlová, Jana

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) are expected to be one of the key drivers determining the diversity of natural plant communities, especially in nutrient-poor and dry habitats. Several previous studies have explored the importance of AMF for the composition of plant communities in various types of habitats. Surprisingly, studies of the role of AMF in nutrient-poor dry grassland communities dominated by less mycotrophic plant species are still relatively rare. We present the results of a 3-year study in which a plant community in a species-rich dry grassland was subjected to the fungicide carbendazim to suppress AMF colonization. We tested the effect of the fungicide on the following parameters: the plant species composition; the number of plant species; the cover of the rare, highly mycorrhiza-dependent species Aster amellus; the cover of the dominant, less mycorrhiza-dependent species Brachypodium pinnatum; and the cover of graminoids and perennial forbs. In addition, we examined the mycorrhizal inoculation potential of the soil. We found that the suppression of AMF with fungicide resulted in substantial changes in plant species composition and significant decrease in species richness, the cover of A. amellus and the cover of perennial forbs. In contrast the species increasing their cover after fungicide application were graminoids--the C3 grasses B. pinnatum and Bromus erectus and the sedge Carex flacca. These species appear to be less mycorrhiza dependent. Moreover, due to their clonal growth and efficient nutrient usage, they are, most likely, better competitors than perennial forbs under fungicide application. Our results thus suggest that AMF are an essential part of the soil communities supporting a high diversity of plant species in species-rich dry grasslands in nutrient-poor habitats. The AMF are especially important for the maintenance of the populations of perennial forbs, many of which are rare and endangered in the area. PMID:24265829

  18. The Effect of AMF Suppression on Plant Species Composition in a Nutrient-Poor Dry Grassland

    PubMed Central

    Dostálek, Tomáš; Pánková, Hana; Münzbergová, Zuzana; Rydlová, Jana

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF) are expected to be one of the key drivers determining the diversity of natural plant communities, especially in nutrient-poor and dry habitats. Several previous studies have explored the importance of AMF for the composition of plant communities in various types of habitats. Surprisingly, studies of the role of AMF in nutrient-poor dry grassland communities dominated by less mycotrophic plant species are still relatively rare. We present the results of a 3-year study in which a plant community in a species-rich dry grassland was subjected to the fungicide carbendazim to suppress AMF colonization. We tested the effect of the fungicide on the following parameters: the plant species composition; the number of plant species; the cover of the rare, highly mycorrhiza-dependent species Aster amellus; the cover of the dominant, less mycorrhiza-dependent species Brachypodium pinnatum; and the cover of graminoids and perennial forbs. In addition, we examined the mycorrhizal inoculation potential of the soil. We found that the suppression of AMF with fungicide resulted in substantial changes in plant species composition and significant decrease in species richness, the cover of A. amellus and the cover of perennial forbs. In contrast the species increasing their cover after fungicide application were graminoids—the C3 grasses B. pinnatum and Bromus erectus and the sedge Carex flacca. These species appear to be less mycorrhiza dependent. Moreover, due to their clonal growth and efficient nutrient usage, they are, most likely, better competitors than perennial forbs under fungicide application. Our results thus suggest that AMF are an essential part of the soil communities supporting a high diversity of plant species in species-rich dry grasslands in nutrient-poor habitats. The AMF are especially important for the maintenance of the populations of perennial forbs, many of which are rare and endangered in the area. PMID:24265829

  19. Nutrient and antinutrient composition of three varieties of Piper species.

    PubMed

    Isong, E U; Essien, I B

    1996-02-01

    The proximate composition of three varieties of Piper guineense (Odusa-Ibibio/Efik) viz. 'Uyat Odusa' (cultivated and peppery), 'Eting-keni Ikot' (wild forest variety) and 'Eting-keni mben inyang' (wild, riverine variety), were determined using available standard methods. Also determined were mineral, antinutrient and ascorbate levels. The cultivated pepperic variety had the highest content of crude protein and moisture (18.9% and 97% respectively) while the wild, riverine variety had the highest content of ether extract, carbohydrate and calories (7.79%, 63.38% and 398 cals respectively). The cultivated variety had appreciable amounts of phosphorus (1.12 mg/100 g), potassium (1.2 mg/100 g), sodium (0.24 mg/100 g), zinc (0.18 mg/100 g), and copper (0.18 mg/100 g) while the forest variety contained more of calcium (12.38 mg/100 g), magnesium (1.21 mg/100 g) and iron (0.85 mg/100 g). The wild riverine variety appeared to have the least mineral content but had the highest ascorbate level of 173.4 mg/100 g. Of four antinutrients assayed, the cultivated pepperic one had the least quantities while the forest variety was highest in hydrocyanic acid (85.8 mg/100 g) and glucosinolates (0.20 mg/100 g). The wild riverine variety had the highest level of total oxalate (165.0 mg/100 g). These quantities are however far below documented toxic levels. PMID:8811726

  20. --Essential-oil composition of the fruits of six Heracleum L. species from Iran: chemotaxonomic significance.

    PubMed

    Radjabian, Tayebeh; Salimi, Azam; Rahmani, Nosrat

    2014-12-01

    The fruit essential oils of Heracleum persicum, H. rechingeri, H. gorganicum, H. rawianum, H. pastinacifolium, and H. anisactis from Iran were obtained by hydrodistillation and characterized by GC-FID and GC/MS analyses. The oils of the six species were compared to determine the similarities and differences among their compositions. Overall, 36 compounds were identified in the fruit oils, accounting for 92.40-96.74% of the total oil compositions. Aliphatic esters constituted the main fraction of the oils (86.61-94.31%), with octyl acetate and hexyl butyrate as the major components. The oil compositions of species belonging to section Pubescentia (H. persicum, H. gorganicum, and H. rechingeri) were discriminated by equally high contents of both octyl acetate (13.84-20.48%) and hexyl butyrate (17.73-38.36%). On the other hand, the oils of H. rawianum, H. pastinacifolium and H. anisactis, belonging to section Wendia, showed lower hexyl butyrate contents (3.62-6.6%) and higher octyl acetate contents (48.71-75.36%) than the former. Moreover, isoelemicin was identified at low amounts (0.10-2.51%) only in the oils of the latter species. The differences in the oil composition among the six species were investigated by hierarchical cluster and principal component analyses, which indicated that the oil composition confirmed well the taxonomical classification based on the morphological and botanical data, and, thus, may provide a reliable marker to discriminate Heracleum species at the intersectional level. PMID:25491338

  1. Nectar production dynamics and sugar composition in two Mucuna species (Leguminosae, Faboideae) with different specialized pollinators

    NASA Astrophysics Data System (ADS)

    Agostini, Kayna; Sazima, Marlies; Galetto, Leonardo

    2011-11-01

    Nectar is secreted in particular rhythms throughout the lifespan of a flower, which allows determining the nectar production dynamics. This paper compares nectar features in Mucuna japira and Mucuna urens describing: dynamics of nectar production, floral response to nectar removal, resorption, nectar sugar composition, and variation in nectar sugar composition. M. japira inflorescence bears 12-21 yellow flowers, which are in anthesis for 7 days, whereas M. urens inflorescence bears 36-54 greenish flowers, but only 1-3 flowers are in anthesis simultaneously that last one night. Nectar volume and sugar concentration were measured, and the amount of sugar was estimated. Qualitative and quantitative nectar sugar composition was determined. Both species had a constant nectar sugar concentration (ca. 10% for M. japira and ca. 16% for M. urens) and secreted high volumes of nectar (ca. 340 μl per flower for M. japira and 310 μl per flower for M. urens), during 5 days for M. japira and 6 h for M. urens, but after the first removal, i.e., when flower opening mechanism is triggered, nectar production stops immediately. Nectar resorption occurred in both species. Nectar sugar composition showed some similarities between the species. Variation in nectar sugar composition occurred in both species. The Mucuna species are dependent on their pollinators to produce fruits and seeds, and they have different strategies to promote the necessary interaction with birds or bats, especially related to nectar and flower characteristics.

  2. Species Composition at the Sub-Meter Level in Discontinuous Permafrost in Subarctic Sweden

    NASA Astrophysics Data System (ADS)

    Anderson, S. M.; Palace, M. W.; Layne, M.; Varner, R. K.; Crill, P. M.

    2013-12-01

    Northern latitudes are experiencing rapid warming. Wetlands underlain by permafrost are particularly vulnerable to warming which results in changes in vegetative cover. Specific species have been associated with greenhouse gas emissions therefore knowledge of species compositional shift allows for the systematic change and quantification of emissions and changes in such emissions. Species composition varies on the sub-meter scale based on topography and other microsite environmental parameters. This complexity and the need to scale vegetation to the landscape level proves vital in our estimation of carbon dioxide (CO2) and methane (CH4) emissions and dynamics. Stordalen Mire (68°21'N, 18°49'E) in Abisko and is located at the edge of discontinuous permafrost zone. This provides a unique opportunity to analyze multiple vegetation communities in a close proximity. To do this, we randomly selected 25 1x1 meter plots that were representative of five major cover types: Semi-wet, wet, hummock, tall graminoid, and tall shrub. We used a quadrat with 64 sub plots and measured areal percent cover for 24 species. We collected ground based remote sensing (RS) at each plot to determine species composition using an ADC-lite (near infrared, red, green) and GoPro (red, blue, green). We normalized each image based on a Teflon white chip placed in each image. Textural analysis was conducted on each image for entropy, angular second momentum, and lacunarity. A logistic regression was developed to examine vegetation cover types and remote sensing parameters. We used a multiple linear regression using forwards stepwise variable selection. We found statistical difference in species composition and diversity indices between vegetation cover types. In addition, we were able to build regression model to significantly estimate vegetation cover type as well as percent cover for specific key vegetative species. This ground-based remote sensing allows for quick quantification of vegetation

  3. Insights into Nitrogen Isotopic Fractionation During Algal Assimilation of Nitrate and Ammonium

    NASA Astrophysics Data System (ADS)

    Evans, S. L.; Swart, P. K.; Capo, T. R.

    2008-12-01

    . Gracilaria may have a competitive advantage as a generalist in terms of nutrient acquisition. As a consequence of the large assimilation factors and species-specific nutrient preferences, significant variations in the stable nitrogen isotopic composition can be produced by simply varying concentrations of available nitrogen. These results cast doubt on conclusions in previous studies attributing isotopic enrichment in algal tissue to anthropogenic nutrient inputs (sewage) to coastal waters.

  4. Nestedness of desert bat assemblages: species composition patterns in insular and terrestrial landscapes.

    PubMed

    Frick, Winifred F; Hayes, John P; Heady, Paul A

    2009-01-01

    Nested patterns of community composition exist when species at depauperate sites are subsets of those occurring at sites with more species. Nested subset analysis provides a framework for analyzing species occurrences to determine non-random patterns in community composition and potentially identify mechanisms that may shape faunal assemblages. We examined nested subset structure of desert bat assemblages on 20 islands in the southern Gulf of California and at 27 sites along the Baja California peninsula coast, the presumable source pool for the insular faunas. Nested structure was analyzed using a conservative null model that accounts for expected variation in species richness and species incidence across sites (fixed row and column totals). Associations of nestedness and island traits, such as size and isolation, as well as species traits related to mobility, were assessed to determine the potential role of differential extinction and immigration abilities as mechanisms of nestedness. Bat faunas were significantly nested in both the insular and terrestrial landscape and island size was significantly correlated with nested structure, such that species on smaller islands tended to be subsets of species on larger islands, suggesting that differential extinction vulnerabilities may be important in shaping insular bat faunas. The role of species mobility and immigration abilities is less clearly associated with nestedness in this system. Nestedness in the terrestrial landscape is likely due to stochastic processes related to random placement of individuals and this may also influence nested patterns on islands, but additional data on abundances will be necessary to distinguish among these potential mechanisms. PMID:18941795

  5. Effects of Previous Land-Use on Plant Species Composition and Diversity in Mediterranean Forests

    PubMed Central

    Kouba, Yacine; Martínez-García, Felipe; de Frutos, Ángel; Alados, Concepción L.

    2015-01-01

    At some point in their history, most forests in the Mediterranean Basin have been subjected to intensive management or converted to agriculture land. Knowing how forest plant communities recovered after the abandonment of forest-management or agricultural practices (including livestock grazing) provides a basis for investigating how previous land management have affected plant species diversity and composition in forest ecosystems. Our study investigated the consequences of historical “land management” practices on present-day Mediterranean forests by comparing species assemblages and the diversity of (i) all plant species and (ii) each ecological group defined by species’ habitat preferences and successional status (i.e., early-, mid-, and late-successional species). We compared forest stands that differed both in land-use history and in successional stage. In addition, we evaluated the value of those stands for biodiversity conservation. The study revealed significant compositional differentiation among stands that was due to among-stand variations in the diversity (namely, species richness and evenness) of early-, intermediate-, and late-successional species. Historical land management has led to an increase in compositional divergences among forest stands and the loss of late-successional forest species. PMID:26397707

  6. Global pattern of phylogenetic species composition of shark and its conservation priority.

    PubMed

    Chen, Hungyen; Kishino, Hirohisa

    2015-10-01

    The diversity of marine communities is in striking contrast with the diversity of terrestrial communities. In all oceans, species richness is low in tropical areas and high at latitudes between 20 and 40°. While species richness is a primary metric used in conservation and management strategies, it is important to take into account the complex phylogenetic patterns of species compositions within communities. We measured the phylogenetic skew and diversity of shark communities throughout the world. We found that shark communities in tropical seas were highly phylogenetically skewed, whereas temperate sea communities had phylogenetically diversified species compositions. Interestingly, although geographically distant from one another, tropical sea communities were all highly skewed toward requiem sharks (Carcharhinidae), hammerhead sharks (Sphyrnidae), and whale sharks (Rhincodon typus). Worldwide, the greatest phylogenetic evenness in terms of clades was found in the North Sea and coastal regions of countries in temperate zones, such as the United Kingdom, Ireland, southern Australia, and Chile. This study is the first to examine patterns of phylogenetic diversity of shark communities on a global scale. Our findings suggest that when establishing conservation activities, it is important to take full account of phylogenetic patterns of species composition and not solely use species richness as a target. Protecting areas of high phylogenetic diversity in sharks, which were identified in this study, could form a broader strategy for protecting other threatened marine species. PMID:26819704

  7. Plant species composition in a temperate forest: Multi-scale patterns and determinants

    NASA Astrophysics Data System (ADS)

    Gazol, Antonio; Ibáñez, Ricardo

    2010-11-01

    We examine the spatial patterns of plant species composition at different scales in a hierarchical sampling design with two surveys of contrasting scale. Additionally, environmental and spatial variables are used to explain the observed patterns. Five datasets were analyzed in this study. The first was obtained as a result of a large-scale spatial survey, in which the study site (132 ha) was divided into 102 large plots of 20 × 20 m. The remaining four datasets were obtained from a small-scale spatial survey, in which four of the former plots were also divided into 100 small plots of 2 × 2 m. Spatial patterns of plant species composition in both spatial surveys were quantified and the factors that influenced them were assessed using multi-scale pattern analysis (MSPA). Over the large-scale survey the topographic structure of the study site created a spatially structured environment, influencing species composition, and the spatial variables indicated that the environment was structured at a broad scale (relative to grain size and extent of the survey). In the small-scale survey the microenvironmental variables that influenced species composition were also spatially structured at a broad scale (relative to grain size and extent of the survey). However, the analyses point to the existence of spatial autocorrelation that seems to be structured at finer scales than the environmental heterogeneity in both study surveys. This study indicates that species composition in this temperate forest is not only determined by the environmental variables studied at either of the two spatial scales considered (large- and small-scale surveys). In both scales, the pure spatial component present in the analyses may be indicating the influence of unmeasured environmental variables and/or biotic processes on species composition patterns. However, while environmental heterogeneity has a broad-scale domain, biotic processes seem to work at finer scales, as is indicated by the spatial

  8. Estimating size and composition of biological communities by modeling the occurrence of species

    USGS Publications Warehouse

    Dorazio, R.M.; Royle, J. Andrew

    2005-01-01

    We develop a model that uses repeated observations of a biological community to estimate the number and composition of species in the community. Estimators of community-level attributes are constructed from model-based estimators of occurrence of individual species that incorporate imperfect detection of individuals. Data from the North American Breeding Bird Survey are analyzed to illustrate the variety of ecologically important quantities that are easily constructed and estimated using our model-based estimators of species occurrence. In particular, we compute site-specific estimates of species richness that honor classical notions of species-area relationships. We suggest extensions of our model to estimate maps of occurrence of individual species and to compute inferences related to the temporal and spatial dynamics of biological communities.

  9. Energy evaluation of algal cell disruption by high pressure homogenisation.

    PubMed

    Yap, Benjamin H J; Dumsday, Geoff J; Scales, Peter J; Martin, Gregory J O

    2015-05-01

    The energy consumption of high pressure homogenisation (HPH) was analysed to determine the feasibility of rupturing algal cells for biodiesel production. Experimentally, the processing capacity (i.e. flow rate), power draw and cell disruption efficiency of HPH were independent of feed concentration (for Nannochloropsis sp. up to 25%w/w solids). Depending on the homogenisation pressure (60-150 MPa), the solids concentration (0.25-25%w/w), and triacylglyceride (TAG) content of the harvested algal biomass (10-30%), the energy consumed by HPH represented between 6% and 110-times the energy density of the resulting biodiesel. Provided the right species (weak cell wall and high TAG content) is selected and the biomass is processed at a sufficiently high solids concentration, HPH can consume a small fraction of the energy content of the biodiesel produced. This study demonstrates the feasibility of process-scale algal cell disruption by HPH based on its energy requirement. PMID:25435068

  10. Species composition of larvae cultured after anthelmintic treatment indicates reduced moxidectin susceptibility of immature Cylicocyclus species in horses.

    PubMed

    Kooyman, F N J; van Doorn, D C K; Geurden, T; Mughini-Gras, L; Ploeger, H W; Wagenaar, J A

    2016-08-30

    For the control of cyathostomins in horses, the macrocyclic lactones (MLs), moxidectin (MOX) and ivermectin (IVM) are the most commonly used anthelmintics. However, reduced activity, observed as shortening of the egg reappearance period (ERP) has been described. Shortening of the ERP may be caused by a decreased susceptibility of immature worms for MLs. Alternatively, immature worms may develop faster into egg producing adults as a result of repeated ML treatments. The species composition of the larval cultures obtained shortly after ML and pyrantel (PYR) treatment can confirm the hypothesis of decreased ML susceptibility, as this is often class-specific, whereas faster development would also occur after treatment with anthelmintics with a different mode of action. From 3 farms with a known history of shortened ERP, 8 horses per farm were selected and divided into 2 groups. The MOX-PYR-MOX group was treated twice with MOX (day 0 and 126) and once with PYR (day 84) and the IVM-PYR-IVM group was treated twice with IVM (day 0 and 98) and once with PYR (day 56). Cultured infective larvae (L3s) were counted and differentiated with the reverse line blot on pooled samples. Per cyathostomin species, the number of larvae per gram was calculated. The efficacy of all ML treatments was 100% and a shortened ERP was found on all 3 farms. The species composition of the larval cultures after ML treatment did not differ significantly from that after PYR treatment in the IVM-PYR-IVM group, but it did differ in the MOX-PYR-MOX group. The larval cultures obtained after MOX treatment consisted mostly of Cylicocyclus nassatus, while after PYR treatment Cylicostephanus longibursatus was the most abundant species. In the cultures from 42days after MOX treatment 6 cyathostomin species from 3 genera were found on the farm with the lowest activity (farm 1), while on the farm with the highest activity (farm 3) only 3 species from one genus were found in the same number of examined L3s. The

  11. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    PubMed

    Brunnschweiler, Juerg M; Abrantes, Kátya G; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion among shark

  12. Long-Term Changes in Species Composition and Relative Abundances of Sharks at a Provisioning Site

    PubMed Central

    Brunnschweiler, Juerg M.; Abrantes, Kátya G.; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today’s recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004–2006 and 2007–2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004–2006 and very rare in the period of 2007–2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion

  13. Species composition and morphology of protostrongylids (Nematoda: Protostrongylidae) in ruminants from Bulgaria.

    PubMed

    Panayotova-Pencheva, Mariana Stancheva

    2011-10-01

    Lungs of 52 ruminants from different regions of Bulgaria, 16 from goats (Capra aegagrus f. domestica L.), 15 from sheep (Ovis ammon f. domestica L.), 11 from mouflons (Ovis musimon L.), and 10 from chamois (Rupicapra rupicapra L.), were investigated. The aim of the study was to determine the species composition of small lungworms in these hosts. The obtained results are summarized with those of previous studies, and a picture of the present status of the species composition of protostrongylids in ruminants from Bulgaria is forwarded. Morphometric data about the species Muellerius capillaris, Cystocaulus ocreatus, Neostrongylus linearis, Protostrongylus brevispiculum, and Protostrongylus rufescens are presented. The data on the morphology of these five species are supplied for the first time both for Bulgaria and the south-east part of the European continent. PMID:21461727

  14. BOREAS TGB-3 Plant Species Composition Data over the NSA Fen

    NASA Technical Reports Server (NTRS)

    Bubier, Jill L.; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOReal Ecosystem-Atmosphere Study Trace Gas Biogeochemistry (BOREAS TGB-3) team collected several data sets that contributed to understanding the measured trace gas fluxes over sites in the Northern Study Area (NSA). This data set contains information about the composition of plant species that were within the collars used to measure Net Ecosystem Exchange of CO2 (NEE). The species composition was identified to understand the differences in NEE among the various plant communities in the NSA fen. The data were collected in July of 1994 and 1996. The data are contained in comma-delimited, ASCII files.

  15. Algal culture studies for CELSS

    NASA Technical Reports Server (NTRS)

    Radmer, R.; Behrens, P.; Arnett, K.; Gladue, R.; Cox, J.; Lieberman, D.

    1987-01-01

    Microalgae are well-suited as a component of a Closed Environmental Life Support System (CELSS), since they can couple the closely related functions of food production and atmospheric regeneration. The objective was to provide a basis for predicting the response of CELSS algal cultures, and thus the food supply and air regeneration system, to changes in the culture parameters. Scenedesmus growth was measured as a function of light intensity, and the spectral dependence of light absorption by the algae as well as algal respiration in the light were determined as a function of cell concentration. These results were used to test and confirm a mathematical model that describes the productivity of an algal culture in terms of the competing processes of photosynthesis and respiration. The relationship of algal productivity to cell concentration was determined at different carbon dioxide concentrations, temperatures, and light intensities. The maximum productivity achieved by an air-grown culture was found to be within 10% of the computed maximum productivity, indicating that CO2 was very efficiently removed from the gas stream by the algal culture. Measurements of biomass productivity as a function of cell concentration at different light intensities indicated that both the productivity and efficiency of light utilization were greater at higher light intensities.

  16. Use of multivariate dispersion to assess water quality based on species composition data.

    PubMed

    Jiang, Yong; Xu, Guangjian; Xu, Henglong

    2016-02-01

    Multivariate dispersion is a powerful approach to determine the variability in species composition of a fauna or a flora and has been considered as a broad β-diversity in global ecological research. To explore the availability of the dispersions based on species composition data for assessing water quality, a dataset of ciliated protozoa in a basin ecosystem, northern China, was studied. Samples were collected from five sampling stations, within a significant heterogeneity of environmental stress. The homogeneity of multivariate dispersions in species composition of the ciliate assemblages represented a clear spatial pattern in response to the environmental stress. Multivariate analysis demonstrated that the spatial variation in species composition of the ciliate was significantly correlated with the changes of environmental variables, especially the nutrients, in combination with the salinity and pH, or alone. Furthermore, the dispersion measure was found to be significantly related to the nutrient. Based on our data, we suggest that multivariate dispersion measures based on species presence/absence data might be used as a potential bioindicator of water quality in marine ecosystems. PMID:26490901

  17. Tree species composition affects the abundance of rowan (Sorbus aucuparia L.) in urban forests in Finland.

    PubMed

    Hamberg, Leena; Lehvävirta, Susanna; Kotze, D Johan; Heikkinen, Juha

    2015-03-15

    Recent studies have shown a considerable increase in the abundance of rowan (Sorbus aucuparia) saplings in urban forests in Finland, yet the reasons for this increase are not well understood. Here we investigated whether canopy cover or tree species composition, i.e., the basal areas of different tree species in Norway spruce dominated urban forests, affects the abundances of rowan seedlings, saplings and trees. Altogether 24 urban forest patches were investigated. We sampled the number of rowan and other saplings, and calculated the basal areas of trees. We showed that rowan abundance was affected by tree species composition. The basal area of rowan trees (≥ 5 cm in diameter at breast height, dbh) decreased with increasing basal area of Norway spruce, while the cover of rowan seedlings increased with an increase in Norway spruce basal area. However, a decrease in the abundance of birch (Betula pendula) and an increase in the broad-leaved tree group (Acer platanoides, Alnus glutinosa, Alnus incana, Amelanchier spicata, Prunus padus, Quercus robur, Rhamnus frangula and Salix caprea) coincided with a decreasing number of rowans. Furthermore, rowan saplings were scarce in the vicinity of mature rowan trees. Although it seems that tree species composition has an effect on rowan, the relationship between rowan saplings and mature trees is complex, and therefore we conclude that regulating tree species composition is not an easy way to keep rowan thickets under control in urban forests in Finland. PMID:25588119

  18. Plankton studies in San Francisco Bay; IV, Phytoplankton abundance and species composition, January 1980 - February 1981

    USGS Publications Warehouse

    Wong, R.L.; Cloern, J.E.

    1982-01-01

    Data are presented on the phytoplankton species composition and abundance in San Francisco Bay from January 1980 through February 1981. Phytoplankton were identified and enumerated in surface samples collected approximately every two weeks at selected stations in the main channel of the Bay, and at shoal stations in the central portion of South San Francisco Bay, San Pablo Bay, and Suisun Bay. Also reported are separate species lists for microphytoplankton (< 60 micrometers) and macrophytoplankton (> 60 micrometers). (Author 's abstract)

  19. Stable and sporadic symbiotic communities of coral and algal holobionts.

    PubMed

    Hester, Eric R; Barott, Katie L; Nulton, Jim; Vermeij, Mark Ja; Rohwer, Forest L

    2016-05-01

    Coral and algal holobionts are assemblages of macroorganisms and microorganisms, including viruses, Bacteria, Archaea, protists and fungi. Despite a decade of research, it remains unclear whether these associations are spatial-temporally stable or species-specific. We hypothesized that conflicting interpretations of the data arise from high noise associated with sporadic microbial symbionts overwhelming signatures of stable holobiont members. To test this hypothesis, the bacterial communities associated with three coral species (Acropora rosaria, Acropora hyacinthus and Porites lutea) and two algal guilds (crustose coralline algae and turf algae) from 131 samples were analyzed using a novel statistical approach termed the Abundance-Ubiquity (AU) test. The AU test determines whether a given bacterial species would be present given additional sampling effort (that is, stable) versus those species that are sporadically associated with a sample. Using the AU test, we show that coral and algal holobionts have a high-diversity group of stable symbionts. Stable symbionts are not exclusive to one species of coral or algae. No single bacterial species was ubiquitously associated with one host, showing that there is not strict heredity of the microbiome. In addition to the stable symbionts, there was a low-diversity community of sporadic symbionts whose abundance varied widely across individual holobionts of the same species. Identification of these two symbiont communities supports the holobiont model and calls into question the hologenome theory of evolution. PMID:26555246

  20. Forest Age and Plant Species Composition Determine the Soil Fungal Community Composition in a Chinese Subtropical Forest

    PubMed Central

    Trogisch, Stefan; Both, Sabine; Scholten, Thomas; Bruelheide, Helge; Buscot, François

    2013-01-01

    Fungal diversity and community composition are mainly related to soil and vegetation factors. However, the relative contribution of the different drivers remains largely unexplored, especially in subtropical forest ecosystems. We studied the fungal diversity and community composition of soils sampled from 12 comparative study plots representing three forest age classes (Young: 10–40 yrs; Medium: 40–80 yrs; Old: ≥80 yrs) in Gutianshan National Nature Reserve in South-eastern China. Soil fungal communities were assessed employing ITS rDNA pyrotag sequencing. Members of Basidiomycota and Ascomycota dominated the fungal community, with 22 putative ectomycorrhizal fungal families, where Russulaceae and Thelephoraceae were the most abundant taxa. Analysis of similarity showed that the fungal community composition significantly differed among the three forest age classes. Forest age class, elevation of the study plots, and soil organic carbon (SOC) were the most important factors shaping the fungal community composition. We found a significant correlation between plant and fungal communities at different taxonomic and functional group levels, including a strong relationship between ectomycorrhizal fungal and non-ectomycorrhizal plant communities. Our results suggest that in subtropical forests, plant species community composition is the main driver of the soil fungal diversity and community composition. PMID:23826151

  1. Vegetation in Bangalore's Slums: Composition, Species Distribution, Density, Diversity, and History.

    PubMed

    Gopal, Divya; Nagendra, Harini; Manthey, Michael

    2015-06-01

    There is widespread acknowledgement of the need for biodiversity and greening to be part of urban sustainability efforts. Yet we know little about greenery in the context of urban poverty, particularly in slums, which constitute a significant challenge for inclusive development in many rapidly growing cities. We assessed the composition, density, diversity, and species distribution of vegetation in 44 slums of Bangalore, India, comparing these to published studies on vegetation diversity in other land-use categories. Most trees were native to the region, as compared to other land-use categories such as parks and streets which are dominated by introduced species. Of the most frequently encountered tree species, Moringa oleifera and Cocos nucifera are important for food, while Ficus religiosa plays a critical cultural and religious role. Tree density and diversity were much lower in slums compared to richer residential neighborhoods. There are also differences in species preferences, with most plant (herb, shrub and vines) species in slums having economic, food, medicinal, or cultural use, while the species planted in richer residential areas are largely ornamental. Historic development has had an impact on species distribution, with older slums having larger sized tree species, while recent slums were dominated by smaller sized tree species with greater economic and food use. Extensive focus on planting trees and plant species with utility value is required in these congested neighborhoods, to provide livelihood support. PMID:25840697

  2. Vegetation in Bangalore's Slums: Composition, Species Distribution, Density, Diversity, and History

    NASA Astrophysics Data System (ADS)

    Gopal, Divya; Nagendra, Harini; Manthey, Michael

    2015-06-01

    There is widespread acknowledgement of the need for biodiversity and greening to be part of urban sustainability efforts. Yet we know little about greenery in the context of urban poverty, particularly in slums, which constitute a significant challenge for inclusive development in many rapidly growing cities. We assessed the composition, density, diversity, and species distribution of vegetation in 44 slums of Bangalore, India, comparing these to published studies on vegetation diversity in other land-use categories. Most trees were native to the region, as compared to other land-use categories such as parks and streets which are dominated by introduced species. Of the most frequently encountered tree species, Moringa oleifera and Cocos nucifera are important for food, while Ficus religiosa plays a critical cultural and religious role. Tree density and diversity were much lower in slums compared to richer residential neighborhoods. There are also differences in species preferences, with most plant (herb, shrub and vines) species in slums having economic, food, medicinal, or cultural use, while the species planted in richer residential areas are largely ornamental. Historic development has had an impact on species distribution, with older slums having larger sized tree species, while recent slums were dominated by smaller sized tree species with greater economic and food use. Extensive focus on planting trees and plant species with utility value is required in these congested neighborhoods, to provide livelihood support.

  3. Changes in Seagrass Species Composition in Northwestern Gulf of Mexico Estuaries: Effects on Associated Seagrass Fauna

    PubMed Central

    Ray, Brandon R.; Johnson, Matthew W.; Cammarata, Kirk; Smee, Delbert L.

    2014-01-01

    The objective of this study was to measure the communities associated with different seagrass species to predict how shifts in seagrass species composition may affect associated fauna. In the northwestern Gulf of Mexico, coverage of the historically dominant shoal grass (Halodule wrightii) is decreasing, while coverage of manatee grass (Syringodium filiforme) and turtle grass (Thalassia testudinum) is increasing. We conducted a survey of fishes, crabs, and shrimp in monospecific beds of shoal, manatee, and turtle grass habitats of South Texas, USA to assess how changes in sea grass species composition would affect associated fauna. We measured seagrass parameters including shoot density, above ground biomass, epiphyte type, and epiphyte abundance to investigate relationships between faunal abundance and these seagrass parameters. We observed significant differences in communities among three seagrass species, even though these organisms are highly motile and could easily travel among the different seagrasses. Results showed species specific relationships among several different characteristics of the seagrass community and individual species abundance. More work is needed to discern the drivers of the complex relationships between individual seagrass species and their associated fauna. PMID:25229897

  4. A decade of predatory control of zooplankton species composition of Lake Michigan

    USGS Publications Warehouse

    Makarewicz, Joseph C.; Bertram, Paul; Lewis, Theodore; Brown, Edward H., Jr.

    1995-01-01

    From 1983 to 1992, 71 species representing 38 genera from the Calanoida, Cladocera, Cyclopoida, Mysidacea, Rotifera, Mollusca and Harpacticoida comprised the offshore zooplankton community of Lake Michigan. Our data demonstrate that the composition and abundance of the calanoid community after 1983 is not unlike that of 1960s and that species diversity of the calanoid community is more diverse than the cladoceran community in the 1990s as compared to the early 1980s. Even though the relative biomass of the cladocerans has remained similar over the 1983-1993 period, the species diversity and evenness of the Cladocera community in the early 1990s is unlike anything that has been previously reported for Lake Michigan. Cladocera dominance is centered in one species, Daphnia galeata mendotae, and only three species of Cladocera were observed in the pelagic region of the lake in 1991 and 1992. Nutrient levels, phytoplankton biomass, and the abundance of planktivorous alewife and bloater chub and Bythotrephes are examined as possible causes of these changes in zooplankton species composition. The increase in Rotifera biomass, but not Crustacea, was correlated with an increase in relative biomass of unicellular algae. Food web models suggest Bythotrephes will cause Lake Michigan's plankton to return to a community similar to that of the 1970s; that is Diaptomus dominated. Such a change has occurred. However, correlational analysis suggest that alewife and bloater chubs (especially juveniles) are affecting size and biomass of larger species of zooplankton as well as Bythotrephes.

  5. EFFECTS OF FORAGE SPECIES ON RIB COMPOSITION, COLOR, AND PALATABILITY IN FORAGE-FINISHED BEEF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forty-seven Angus-crossbred steers were used to evaluate the effects of forage species grazed in the last 41 d of the finishing period on rib composition, color, and palatability in forage-finished beef and compared to traditional high concentrate finished. Steers grazed naturalized pastures (bluegr...

  6. Influence of Tree Species Composition and Community Structure on Carbon Density in a Subtropical Forest

    PubMed Central

    Hu, Yanqiu; Su, Zhiyao; Li, Wenbin; Li, Jingpeng; Ke, Xiandong

    2015-01-01

    We assessed the impact of species composition and stand structure on the spatial variation of forest carbon density using data collected from a 4-ha plot in a subtropical forest in southern China. We found that 1) forest biomass carbon density significantly differed among communities, reflecting a significant effect of community structure and species composition on carbon accumulation; 2) soil organic carbon density increased whereas stand biomass carbon density decreased across communities, indicating that different mechanisms might account for the accumulation of stand biomass carbon and soil organic carbon in the subtropical forest; and 3) a small number of tree individuals of the medium- and large-diameter class contributed predominantly to biomass carbon accumulation in the community, whereas a large number of seedlings and saplings were responsible for a small proportion of the total forest carbon stock. These findings demonstrate that both biomass carbon and soil carbon density in the subtropical forest are sensitive to species composition and community structure, and that heterogeneity in species composition and stand structure should be taken into account to ensure accurate forest carbon accounting. PMID:26317523

  7. Bumble bees (Hymenoptera: Apidae: Bombus spp.) of interior Alaska: Species composition, distribution, seasonal biology, and parasites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite the ecological and agricultural significance of bumble bees in Alaska, very little is known and published about this important group at the regional level. The objectives of this study were to provide baseline data on species composition, distribution, seasonal biology, and parasites of the ...

  8. Proximate composition and mineral content of two edible species of Cnidoscolus (tree spinach).

    PubMed

    Kuti, J O; Kuti, H O

    1999-01-01

    Proximate composition and mineral content of raw and cooked leaves of two edible tree spinach species (Cnidoscolus chayamansa and C. aconitifolius), known locally as 'chaya', were determined and compared with that of a traditional green vegetable, spinach (Spinicia oleraceae). Results of the study indicated that the edible leafy parts of the two chaya species contained significantly (p<0.05) greater amounts of crude protein, crude fiber, Ca, K, Fe, ascorbic acid and beta-carotene than the spinach leaf. However, no significant (p>0.05) differences were found in nutritional composition and mineral content between the chaya species, except minor differences in the relative composition of fatty acids, protein and amino acids. Cooking of chaya leaves slightly reduced nutritional composition of both chaya species. Cooking is essential prior to consumption to inactivate the toxic hydrocyanic glycosides present in chaya leaves. Based on the results of this study, the edible chaya leaves may be good dietary sources of minerals (Ca, K and Fe) and vitamins (ascorbic acid and beta-carotene). PMID:10540979

  9. Comparison of the chemical compositions and nutritive values of various pumpkin (Cucurbitaceae) species and parts.

    PubMed

    Kim, Mi Young; Kim, Eun Jin; Kim, Young-Nam; Choi, Changsun; Lee, Bog-Hieu

    2012-02-01

    Pumpkins have considerable variation in nutrient contents depending on the cultivation environment, species, or part. In this study, the general chemical compositions and some bioactive components, such as tocopherols, carotenoids, and β-sitosterol, were analyzed in three major species of pumpkin (Cucurbitaceae pepo, C. moschata, and C. maxima) grown in Korea and also in three parts (peel, flesh, and seed) of each pumpkin species. C. maxima had significantly more carbohydrate, protein, fat, and fiber than C. pepo or C. moschata (P < 0.05). The moisture content as well as the amino acid and arginine contents in all parts of the pumpkin was highest in C. pepo. The major fatty acids in the seeds were palmitic, stearic, oleic, and linoleic acids. C. pepo and C. moschata seeds had significantly more γ-tocopherol than C. maxima, whose seeds had the highest β-carotene content. C. pepo seeds had significantly more β-sitosterol than the others. Nutrient compositions differed considerably among the pumpkin species and parts. These results will be useful in updating the nutrient compositions of pumpkin in the Korean food composition database. Additional analyses of various pumpkins grown in different years and in different areas of Korea are needed. PMID:22413037

  10. Species Composition and Abundance of Stink Bugs (Hemiptera: Heteroptera: Pentatomidae) in Minnesota Field Corn.

    PubMed

    Koch, Robert L; Pahs, Tiffany

    2015-04-01

    In response to concerns of increasing significance of stink bugs (Hemiptera: Heteroptera: Pentatomidae) in northern states, a survey was conducted over 2 yr in Minnesota to characterize the Pentatomidae associated with field corn, Zea mays L. Halyomorpha halys (Stål), an exotic species, was not detected in this survey, despite continued detection of this species as an invader of human-made structures in Minnesota. Five species of Pentatomidae (four herbivorous; one predatory) were collected from corn. Across years, Euschistus variolarius (Palisot de Beauvois) and Euschistus servus euschistoides (Vollenhoven) had the greatest relative abundances and frequencies of detection. In 2012, the abundance of herbivorous species exceeded 25 nymphs and adults per 100 plants (i.e., an economic threshold) in 0.48% of fields. However, the abundance of herbivorous species did not reach economic levels in any fields sampled in 2013. The frequency of detection of herbivorous species and ratio of nymphs to adults was highest during reproductive growth stages of corn. The predator species, Podisus maculiventris (Say), was detected in 0 to 0.32% of fields. These results provide baseline information on the species composition and abundance of Pentatomidae in Minnesota field corn, which will be necessary for documentation of changes to this fauna as a result of the invasion of H. halys and to determine if some native species continue to increase in abundance in field crops. PMID:26313176

  11. The species composition of thrips (insecta: thysanoptera) inhabiting mango orchards in pulau pinang, malaysia.

    PubMed

    Aliakbarpour, Hamaseh; Rawi, Che Salmah Md

    2012-05-01

    A field study was conducted at two localities on Pulau Pinang, Malaysia, during two consecutive mango flowering seasons in 2009 to identify variations in the species composition of thrips infesting treated and untreated mango (Mangifera indica L.) orchards. The CO2 immobilisation technique and the cutting method were used to recover different thrips species from mango panicles and weed host plants, respectively. The mango panicles and various weed species within the treated orchard were found to harbour four thrips species from the family Thripidae. These species were identified as Thrips hawaiiensis (Morgan), Scirtothrips dorsalis (Hood), Frankliniella schultzei (Trybom) and Megalurothrips usitatus (Bagnall). The weed species Mimosa pudica, Cleome rutidosperma, Echinochloa colonum, Borreria laevicaulis, Veronia cinerea and Asystasia coromandeliana served as additional hosts to these thrips. Six thrips species were found in the untreated orchard. These species included Thrips palmi (Karny), Haplothrips sp. (Amyot and Serville) and the four thrips species found in the treated orchard. A brief description of the larvae for each genus is provided. PMID:24575225

  12. Plasticity in plant functional traits is shaped by variability in neighbourhood species composition.

    PubMed

    Abakumova, Maria; Zobel, Kristjan; Lepik, Anu; Semchenko, Marina

    2016-07-01

    Plant functional traits can vary widely as a result of phenotypic plasticity to abiotic conditions. Trait variation may also reflect responses to the identity of neighbours, although not all species are equally responsive to their biotic surroundings. We hypothesized that responses to neighbours are shaped by spatial community patterns and resulting variability in neighbour composition. More precisely, we tested the theoretical prediction that plasticity is most likely to evolve if alternative environments (in this case, different neighbour species) are common and encountered at similar frequencies. We estimated the frequencies of encountering different neighbour species in the field for 27 grassland species and measured the aboveground morphological responses of each species to conspecific vs heterospecific neighbours in a common garden. Responses to neighbour identity were dependent on how frequently the experimental neighbours were encountered by the focal species in their home community, with the greatest plasticity observed in species that encountered both neighbours (conspecific and heterospecific) with high and even frequency. Biotic interactions with neighbouring species can impose selection on plasticity in functional traits, which may feed back through trait divergence and niche differentiation to influence species coexistence and community structure. PMID:26996338

  13. Comparison of the Essential Oil Composition of Selected Impatiens Species and Its Antioxidant Activities.

    PubMed

    Szewczyk, Katarzyna; Kalemba, Danuta; Komsta, Łukasz; Nowak, Renata

    2016-01-01

    The present paper describes the chemical composition of the essential oils obtained by hydrodistillation from four Impatiens species, Impatiens glandulifera Royle, I. parviflora DC., I. balsamina L. and I. noli-tangere L. The GC and GC-MS methods resulted in identification of 226 volatile compounds comprising from 61.7%-88.2% of the total amount. The essential oils differed significantly in their composition. Fifteen compounds were shared among the essential oils of all investigated Impatiens species. The majority of these constituents was linalool (0.7%-15.1%), hexanal (0.2%-5.3%) and benzaldehyde (0.1%-10.2%). Moreover, the antioxidant activity of the essential oils was investigated using different methods. The chemical composition of the essential oils and its antioxidant evaluation are reported for the first time from the investigated taxon. PMID:27598111

  14. A simple model for forecast of coastal algal blooms

    NASA Astrophysics Data System (ADS)

    Wong, Ken T. M.; Lee, Joseph H. W.; Hodgkiss, I. J.

    2007-08-01

    In eutrophic sub-tropical coastal waters around Hong Kong and South China, algal blooms (more often called red tides) due to the rapid growth of microscopic phytoplankton are often observed. Under favourable environmental conditions, these blooms can occur and subside over rather short time scales—in the order of days to a few weeks. Very often, these blooms are observed in weakly flushed coastal waters under calm wind conditions—with or without stratification. Based on high-frequency field observations of harmful algal blooms at two coastal mariculture zones in Hong Kong, a mathematical model has been developed to forecast algal blooms. The model accounts for algal growth, decay, settling and vertical turbulent mixing, and adopts the same assumptions as the classical Riley, Stommel and Bumpus model (Riley, G.A., Stommel, H., Bumpus, D.F., 1949. Quantitative ecology of the plankton of the western North Atlantic. Bulletin of the Bingham Oceanographic Collection Yale University 12, 1-169). It is shown that for algal blooms to occur, a vertical stability criterion, E < 4 μl2/ π2, must be satisfied, where E, μ, l are the vertical turbulent diffusivity, algal growth rate, and euphotic layer depth respectively. In addition, a minimum nutrient threshold concentration must be reached. Moreover, with a nutrient competition consideration, the type of bloom (caused by motile or non-motile species) can be classified. The model requires as input simple and readily available field measurements of water column transparency and nutrient concentration, and representative maximum algal growth rate of the motile and non-motile species. In addition, with the use of three-dimensional hydrodynamic circulation models, simple relations are derived to estimate the vertical mixing coefficient as a function of tidal range, wind speed, and density stratification. The model gives a quick assessment of the likelihood of algal bloom occurrence, and has been validated against field

  15. Fuel options from microalgae with representative chemical compositions

    SciTech Connect

    Feinberg, D. A.

    1984-07-01

    Representative species of microalgae are examined with respect to their reported chemical compositions. Each species is analyzed under a variety of culture conditions, with the objective being to characterize an optimum mixture of fuel products (e.g., methane, ethanol, methylester) which should be produced by the particular species. Historically the emphasis has been on the entire algal cell mass. Using the reported chemical composition for the representative species under specific sets of growth conditions, some conclusions can be drawn about the preferred fuel product conversion routes that could be employed. 10 references, 7 figures, 12 tables.

  16. Species composition and seasonal abundance of Chaetognatha in the subtropical coastal waters of Hong Kong

    NASA Astrophysics Data System (ADS)

    Tse, P.; Hui, S. Y.; Wong, C. K.

    2007-06-01

    Species composition, species diversity and seasonal abundance of chaetognaths were studied in Tolo Harbour and the coastal waters of eastern Hong Kong. Tolo Harbour is a semi-enclosed and poorly flushed bay with a long history of eutrophication. It opens into the eastern coast of Hong Kong which is fully exposed to water currents from the South China Sea. Zooplankton samples were collected monthly from July 2003 to July 2005 at six stations. Twenty species of chaetognaths were identified. They included six species of the genus Aidanosagitta ( Aidanosagitta neglecta, Aidanosagitta delicata, Aidanosagitta johorensis, Aidanosagitta regularis, Aidanosagitta bedfordii and Aidanosagitta crassa), four species of the genus Zonosagitta ( Zonosagitta nagae, Zonosagitta bedoti, Zonosagitta bruuni and Zonosagitta pulchra), three species of the genus Ferosagitta ( Ferosagitta ferox, Ferosagitta tokiokai and Ferosagitta robusta) and one species each from the genera Serratosagitta ( Serratosagitta pacifica), Decipisagitta ( Decipisagitta decipiens), Flaccisagitta ( Flaccisagitta enflata), Krohnitta ( Krohnitta pacifica), Mesosagitta ( Mesosagitta minima), Pterosagitta ( Pterosagitta draco) and Sagitta ( Sagitta bipunctata). The most abundant species were Flaccisagitta enflata, A. neglecta and A. delicata. Averaged over the entire study period, the densities of Flaccisagitta enflata, A. neglecta and A. delicata were 9.3, 6.6 and 5.2 ind. m -3, respectively. Overall, these species constituted 39.7%, 28.2% and 22.0% of all chaetognaths collected in the study. Averaged over the entire study, the density of most of the low abundance species was <0.6 ind. m -3. Flaccisagitta enflata occurred throughout the year at all sampling stations. Aidanosagitta neglecta occurred at all sampling stations, but was most common in summer. Aidanosagitta delicata was most common in Tolo Harbour during summer. Tolo Harbour supported larger populations, but fewer species of chaetognaths than the

  17. Measuring size and composition of species pools: a comparison of dark diversity estimates.

    PubMed

    de Bello, Francesco; Fibich, Pavel; Zelený, David; Kopecký, Martin; Mudrák, Ondřej; Chytrý, Milan; Pyšek, Petr; Wild, Jan; Michalcová, Dana; Sádlo, Jiří; Šmilauer, Petr; Lepš, Jan; Pärtel, Meelis

    2016-06-01

    Ecological theory and biodiversity conservation have traditionally relied on the number of species recorded at a site, but it is agreed that site richness represents only a portion of the species that can inhabit particular ecological conditions, that is, the habitat-specific species pool. Knowledge of the species pool at different sites enables meaningful comparisons of biodiversity and provides insights into processes of biodiversity formation. Empirical studies, however, are limited due to conceptual and methodological difficulties in determining both the size and composition of the absent part of species pools, the so-called dark diversity. We used >50,000 vegetation plots from 18 types of habitats throughout the Czech Republic, most of which served as a training dataset and 1083 as a subset of test sites. These data were used to compare predicted results from three quantitative methods with those of previously published expert estimates based on species habitat preferences: (1) species co-occurrence based on Beals' smoothing approach; (2) species ecological requirements, with envelopes around community mean Ellenberg values; and (3) species distribution models, using species environmental niches modeled by Biomod software. Dark diversity estimates were compared at both plot and habitat levels, and each method was applied in different configurations. While there were some differences in the results obtained by different methods, particularly at the plot level, there was a clear convergence, especially at the habitat level. The better convergence at the habitat level reflects less variation in local environmental conditions, whereas variation at the plot level is an effect of each particular method. The co-occurrence agreed closest the expert estimate, followed by the method based on species ecological requirements. We conclude that several analytical methods can estimate species pools of given habitats. However, the strengths and weaknesses of different methods

  18. Molecular species composition of plant cardiolipin determined by liquid chromatography mass spectrometry.

    PubMed

    Zhou, Yonghong; Peisker, Helga; Dörmann, Peter

    2016-07-01

    Cardiolipin (CL), an anionic phospholipid of the inner mitochondrial membrane, provides essential functions for stabilizing respiratory complexes and is involved in mitochondrial morphogenesis and programmed cell death in animals. The role of CL and its metabolism in plants are less well understood. The measurement of CL in plants, including its molecular species composition, is hampered by the fact that CL is of extremely low abundance, and that plants contain large amounts of interfering compounds including galactolipids, neutral lipids, and pigments. We used solid phase extraction by anion exchange chromatography to purify CL from crude plant lipid extracts. LC/MS was used to determine the content and molecular species composition of CL. Thus, up to 23 different molecular species of CL were detected in different plant species, including Arabidopsis, mung bean, spinach, barley, and tobacco. Similar to animals, plant CL is dominated by highly unsaturated species, mostly containing linoleic and linolenic acid. During phosphate deprivation or exposure to an extended dark period, the amount of CL decreased in Arabidopsis, accompanied with an increased degree in unsaturation. The mechanism of CL remodeling during stress, and the function of highly unsaturated CL molecular species, remains to be defined. PMID:27179363

  19. Small herbivores suppress algal accumulation on Agatti atoll, Indian Ocean

    NASA Astrophysics Data System (ADS)

    Cernohorsky, Nicole H.; McClanahan, Timothy R.; Babu, Idrees; Horsák, Michal

    2015-12-01

    Despite large herbivorous fish being generally accepted as the main group responsible for preventing algal accumulation on coral reefs, few studies have experimentally examined the relative importance of herbivore size on algal communities. This study used exclusion cages with two different mesh sizes (1 × 1 cm and 6 × 6 cm) to investigate the impact of different-sized herbivores on algal accumulation rates on the shallow (<2 m) back-reef of Agatti atoll, Lakshadweep. The fine-mesh cages excluded all visible herbivores, which had rapid and lasting effects on the benthic communities, and, after 127 d of deployment, there was a visible and significant increase in algae (mainly macroalgae) with algal volume being 13 times greater than in adjacent open areas. The coarse-mesh cages excluded larger fishes (>8 cm body depth) while allowing smaller fishes to access the plots. In contrast to the conclusions of most previous studies, the exclusion of large herbivores had no significant effect on the accumulation of benthic algae and the amount of algae present within the coarse-mesh cages was relatively consistent throughout the experimental period (around 50 % coverage and 1-2 mm height). The difference in algal accumulation between the fine-mesh and coarse-mesh cages appears to be related to the actions of small individuals from 12 herbivorous fish species (0.17 ind. m-2 and 7.7 g m-2) that were able to enter through the coarse mesh. Although restricted to a single habitat, these results suggest that when present in sufficient densities and diversity, small herbivorous fishes can prevent the accumulation of algal biomass on coral reefs.

  20. Environmental Gradients Explain Species Richness and Community Composition of Coastal Breeding Birds in the Baltic Sea

    PubMed Central

    Nord, Maria; Forslund, Pär

    2015-01-01

    Scientifically-based systematic conservation planning for reserve design requires knowledge of species richness patterns and how these are related to environmental gradients. In this study, we explore a large inventory of coastal breeding birds, in total 48 species, sampled in 4646 1 km2 squares which covered a large archipelago in the Baltic Sea on the east coast of Sweden. We analysed how species richness (α diversity) and community composition (β diversity) of two groups of coastal breeding birds (specialists, i.e. obligate coastal breeders; generalists, i.e. facultative coastal breeders) were affected by distance to open sea, land area, shoreline length and archipelago width. The total number of species per square increased with increasing shoreline length, but increasing land area counteracted this effect in specialists. The number of specialist bird species per square increased with decreasing distance to open sea, while the opposite was true for the generalists. Differences in community composition between squares were associated with differences in land area and distance to open sea, both when considering all species pooled and each group separately. Fourteen species were nationally red-listed, and showed similar relationships to the environmental gradients as did all species, specialists and generalists. We suggest that availability of suitable breeding habitats, and probably also proximity to feeding areas, explain much of the observed spatial distributions of coastal birds in this study. Our findings have important implications for systematic conservation planning of coastal breeding birds. In particular, we provide information on where coastal breeding birds occur and which environments they seem to prefer. Small land areas with long shorelines are highly valuable both in general and for red-listed species. Thus, such areas should be prioritized for protection against human disturbance and used by management in reserve selection. PMID:25714432

  1. Landscape-scale variation in plant community composition of an African savanna from airborne species mapping.

    PubMed

    Baldeck, C A; Colgan, M S; Féret, J B; Levick, S R; Martin, R E; Asner, G P

    2014-01-01

    Information on landscape-scale patterns in species distributions and community types is vital for ecological science and effective conservation assessment and planning. However, detailed maps of plant community structure at landscape scales seldom exist due to the inability of field-based inventories to map a sufficient number of individuals over large areas. The Carnegie Airborne Observatory (CAO) collected hyperspectral and lidar data over Kruger National Park, South Africa, and these data were used to remotely identify > 500 000 tree and shrub crowns over a 144-km2 landscape using stacked support vector machines. Maps of community compositional variation were produced by ordination and clustering, and the importance of hillslope-scale topo-edaphic variation in shaping community structure was evaluated with redundancy analysis. This remote species identification approach revealed spatially complex patterns in woody plant communities throughout the landscape that could not be directly observed using field-based methods alone. We estimated that topo-edaphic variables representing catenal sequences explained 21% of species compositional variation, while we also uncovered important community patterns that were unrelated to catenas, indicating a large role for other soil-related factors in shaping the savanna community. Our results demonstrate the ability of airborne species identification techniques to map biodiversity for the evaluation of ecological controls on community composition over large landscapes. PMID:24640536

  2. Evolutionary Divergences in Root Exudate Composition among Ecologically-Contrasting Helianthus Species

    PubMed Central

    Bowsher, Alan W.; Ali, Rifhat; Harding, Scott A.; Tsai, Chung-Jui; Donovan, Lisa A.

    2016-01-01

    Plant roots exude numerous metabolites into the soil that influence nutrient availability. Although root exudate composition is hypothesized to be under selection in low fertility soils, few studies have tested this hypothesis in a phylogenetic framework. In this study, we examined root exudates of three pairs of Helianthus species chosen as phylogenetically-independent contrasts with respect to native soil nutrient availability. Under controlled environmental conditions, seedlings were grown to the three-leaf-pair stage, then transferred to either high or low nutrient treatments. After five days of nutrient treatments, we used gas chromatography-mass spectrometry for analysis of root exudates, and detected 37 metabolites across species. When compared in the high nutrient treatment, species native to low nutrient soils exhibited overall higher exudation than their sister species native to high nutrient soils in all three species pairs, providing support for repeated evolutionary shifts in response to native soil fertility. Species native to low nutrient soils and those native to high nutrient soils responded similarly to low nutrient treatments with increased exudation of organic acids (fumaric, citric, malic acids) and glucose, potentially as a mechanism to enhance nutrition acquisition. However, species native to low nutrient soils also responded to low nutrient treatments with a larger decrease in exudation of amino acids than species native to high nutrient soils in all three species pairs. This indicates that species native to low nutrient soils have evolved a unique sensitivity to changes in nutrient availability for some, but not all, root exudates. Overall, these repeated evolutionary divergences between species native to low nutrient soils and those native to high nutrient soils provide evidence for the adaptive value of root exudation, and its plasticity, in contrasting soil environments. PMID:26824236

  3. Evolutionary Divergences in Root Exudate Composition among Ecologically-Contrasting Helianthus Species.

    PubMed

    Bowsher, Alan W; Ali, Rifhat; Harding, Scott A; Tsai, Chung-Jui; Donovan, Lisa A

    2016-01-01

    Plant roots exude numerous metabolites into the soil that influence nutrient availability. Although root exudate composition is hypothesized to be under selection in low fertility soils, few studies have tested this hypothesis in a phylogenetic framework. In this study, we examined root exudates of three pairs of Helianthus species chosen as phylogenetically-independent contrasts with respect to native soil nutrient availability. Under controlled environmental conditions, seedlings were grown to the three-leaf-pair stage, then transferred to either high or low nutrient treatments. After five days of nutrient treatments, we used gas chromatography-mass spectrometry for analysis of root exudates, and detected 37 metabolites across species. When compared in the high nutrient treatment, species native to low nutrient soils exhibited overall higher exudation than their sister species native to high nutrient soils in all three species pairs, providing support for repeated evolutionary shifts in response to native soil fertility. Species native to low nutrient soils and those native to high nutrient soils responded similarly to low nutrient treatments with increased exudation of organic acids (fumaric, citric, malic acids) and glucose, potentially as a mechanism to enhance nutrition acquisition. However, species native to low nutrient soils also responded to low nutrient treatments with a larger decrease in exudation of amino acids than species native to high nutrient soils in all three species pairs. This indicates that species native to low nutrient soils have evolved a unique sensitivity to changes in nutrient availability for some, but not all, root exudates. Overall, these repeated evolutionary divergences between species native to low nutrient soils and those native to high nutrient soils provide evidence for the adaptive value of root exudation, and its plasticity, in contrasting soil environments. PMID:26824236

  4. Comparison of Phylogeny, Venom Composition and Neutralization by Antivenom in Diverse Species of Bothrops Complex

    PubMed Central

    Peixoto, Pedro S.; Bernardoni, Juliana L.; Oliveira, Sâmella S.; Portes-Junior, José Antonio; Mourão, Rosa Helena V.; Lima-dos-Santos, Isa; Sano-Martins, Ida S.; Chalkidis, Hipócrates M.; Valente, Richard H.; Moura-da-Silva, Ana M.

    2013-01-01

    In Latin America, Bothrops snakes account for most snake bites in humans, and the recommended treatment is administration of multispecific Bothrops antivenom (SAB – soro antibotrópico). However, Bothrops snakes are very diverse with regard to their venom composition, which raises the issue of which venoms should be used as immunizing antigens for the production of pan-specific Bothrops antivenoms. In this study, we simultaneously compared the composition and reactivity with SAB of venoms collected from six species of snakes, distributed in pairs from three distinct phylogenetic clades: Bothrops, Bothropoides and Rhinocerophis. We also evaluated the neutralization of Bothrops atrox venom, which is the species responsible for most snake bites in the Amazon region, but not included in the immunization antigen mixture used to produce SAB. Using mass spectrometric and chromatographic approaches, we observed a lack of similarity in protein composition between the venoms from closely related snakes and a high similarity between the venoms of phylogenetically more distant snakes, suggesting little connection between taxonomic position and venom composition. P-III snake venom metalloproteinases (SVMPs) are the most antigenic toxins in the venoms of snakes from the Bothrops complex, whereas class P-I SVMPs, snake venom serine proteinases and phospholipases A2 reacted with antibodies in lower levels. Low molecular size toxins, such as disintegrins and bradykinin-potentiating peptides, were poorly antigenic. Toxins from the same protein family showed antigenic cross-reactivity among venoms from different species; SAB was efficient in neutralizing the B. atrox venom major toxins. Thus, we suggest that it is possible to obtain pan-specific effective antivenoms for Bothrops envenomations through immunization with venoms from only a few species of snakes, if these venoms contain protein classes that are representative of all species to which the antivenom is targeted. PMID

  5. Degradation in the dentin-composite interface subjected to multi-species biofilm challenges.

    PubMed

    Li, Y; Carrera, C; Chen, R; Li, J; Lenton, P; Rudney, J D; Jones, R S; Aparicio, C; Fok, A

    2014-01-01

    Oral biofilms can degrade the components in dental resin-based composite restorations, thus compromising marginal integrity and leading to secondary caries. This study investigates the mechanical integrity of the dentin-composite interface challenged with multi-species oral biofilms. While most studies used single-species biofilms, the present study used a more realistic, diverse biofilm model produced directly from plaques collected from donors with a history of early childhood caries. Dentin-composite disks were made using bovine incisor roots filled with Z100(TM) or Filtek(TM) LS (3M ESPE). The disks were incubated for 72 h in paired CDC biofilm reactors, using a previously published protocol. One reactor was pulsed with sucrose, and the other was not. A sterile saliva-only control group was run with sucrose pulsing. The disks were fractured under diametral compression to evaluate their interfacial bond strength. The surface deformation of the disks was mapped using digital image correlation to ascertain the fracture origin. Fracture surfaces were examined using scanning electron microscopy/energy-dispersive X-ray spectroscopy to assess demineralization and interfacial degradation. Dentin demineralization was greater under sucrose-pulsed biofilms, as the pH dropped <5.5 during pulsing, with LS and Z100 specimens suffering similar degrees of surface mineral loss. Biofilm growth with sucrose pulsing also caused preferential degradation of the composite-dentin interface, depending on the composite/adhesive system used. Specifically, Z100 specimens showed greater bond strength reduction and more frequent cohesive failure in the adhesive layer. This was attributed to the inferior dentin coverage by Z100 adhesive, which possibly led to a higher level of chemical and enzymatic degradation. The results suggested that factors other than dentin demineralization were also responsible for interfacial degradation. A clinically relevant in vitro biofilm model was therefore

  6. Ecological Significance of a Geomorphic Stream Classification: Species and Functional Group Composition of Riparian Plant Communities

    NASA Astrophysics Data System (ADS)

    Shaw, J. R.; Cooper, D. J.

    2014-12-01

    We tested the ecological significance of a geomorphic classification of Sonoran Desert ephemeral stream channels based on channel plan-form, degree of lateral confinement, and boundary material composition. This typology has been shown to discriminate among channel geometry and hydraulic characteristics for bedrock, bedrock with alluvium, incised alluvium, braided, and piedmont headwater channels. We examined stream reach-scale relationships of geomorphic stream types to the relative cover and density of perennial plant species and functional groups, and identified the dominant fluvial drivers, within riparian communities at 101 ephemeral stream reaches on the U.S. Army Yuma Proving Ground and Barry M. Goldwater Air Force Range in southwestern Arizona, USA. Nonparametric multivariate analysis of variance showed that species and functional group composition differed significantly among geomorphic stream types, both in terms of relative cover and density. Partitioning of among-site multivariate dissimilarity revealed that species compositional differences between stream types were caused largely by variation in the cover and density of the most common members of the regional flora. Distinctive functional group composition among reach types resulted from differences in the cover and density of drought-deciduous shrubs and subshrubs, evergreen trees and shrubs, and photosynthetic-stemmed trees. Comparison of environmental and biotic dissimilarity matrices highlighted the role of channel gradient as the dominant abiotic driver of riparian plant community composition, with stream channel elevation and width:depth providing additional explanatory power. Distinctive riparian plant community composition among the geomorphic stream types demonstrates the ecological significance of this a priori channel classification, and indicates its potential utility in understanding spatial patterns of ecological dynamics, sample stratification for process-based studies, and reference

  7. Degradation in the Dentin-Composite Interface Subjected to Multi-Species Biofilm Challenges

    PubMed Central

    Li, Yuping; Carrera, Carola; Chen, Ruoqiong; Li, Jianying; Patricia, Lenton; Rudney, Joel. D.; Jones, Robert S.; Aparicio, Conrado; Fok, Alex

    2013-01-01

    Oral biofilms can degrade the components in dental resin-based composite restorations, thus compromising marginal integrity and leading to secondary caries. In this study, we investigated the mechanical integrity of the dentin-composite interface challenged with multi-species oral biofilms. While most studies used single-species biofilms, we used a more realistic, diverse biofilm model produced directly from plaques collected from donors with a history of early childhood caries. Dentin–composite disks were made using bovine incisor roots filled with Z100™ or Filtek™ LS (3M ESPE). The disks were incubated for 72hr in paired CDC biofilm reactors, using a previously published protocol. One reactor was pulsed with sucrose, and the other was not. A sterile saliva-only control group was run with sucrose pulsing. The disks were fractured under diametral compression to evaluate their interfacial bond strength. Surface deformation of the disks was mapped using digital image correlation (DIC) to ascertain fracture origin. Fracture surfaces were examined using SEM/EDS to assess demineralization and interfacial degradation. Dentin demineralization was greater under sucrose-pulsed biofilms, as the pH dropped below 5.5 during pulsing, with LS and Z100 specimens suffering similar degrees of surface mineral loss. Biofilm growth with sucrose pulsing also caused preferential degradation of the composite-dentin interface, depending on the composite/adhesive system used. Specifically, Z100 specimens showed greater bond strength reduction and more frequent cohesive failure in the adhesive layer. This was attributed to the inferior dentin coverage by Z100 adhesive which possibly led to a higher level of chemical and enzymatic degradation. The results suggested that factors other than dentin demineralization were also responsible for interfacial degradation. We have thus developed a clinically relevant in vitro biofilm model which would allow us to effectively assess the

  8. Changes in plant species composition of coastal dune habitats over a 20-year period.

    PubMed

    Del Vecchio, Silvia; Prisco, Irene; Acosta, Alicia T R; Stanisci, Angela

    2015-01-01

    Coastal sandy ecosystems are increasingly being threatened by human pressure, causing loss of biodiversity, habitat degradation and landscape modifications. However, there are still very few detailed studies focussing on compositional changes in coastal dune plant communities over time. In this work, we investigated how coastal dune European Union (EU) habitats (from pioneer annual beach communities to Mediterranean scrubs on the landward fixed dunes) have changed during the last 20 years. Using phytosociological relevés conducted in 1989-90 and in 2010-12, we investigated changes in floristic composition over time. We then compared plant cover and the proportion of ruderal, alien and habitat diagnostic species ('focal species') in the two periods. Finally, we used Ellenberg indicator values to define the 'preferences' of the plant species for temperature and moisture. We found that only fore dune habitats showed significant differences in species cover between the two time periods, with higher plant cover in the more recent relevés and a significant increase in thermophilic species. Although previous studies have demonstrated consistent habitat loss in this area, we observed that all coastal dune plant communities remain well represented, after a 20-year period. However, fore dunes have been experiencing significant compositional changes. Although we cannot confirm whether the observed changes are strictly related to climatic changes, to human pressure or to both, we hypothesize that a moderate increment in average yearly temperature may have promoted the increase in plant cover and the spread of thermophilic species. Thus, even though human activities are major driving forces of change in coastal dune vegetation, at the community scale climatic factors may also play important roles. Our study draws on re-visitation studies which appear to constitute a powerful tool for the assessment of the conservation status of EU habitats. PMID:25750408

  9. Fatty acid composition of six Centaurea species growing in Konya, Turkey.

    PubMed

    Tekeli, Yener; Sezgin, Mehmet; Aktumsek, Abdurrahman; Ozmen Guler, Gokalp; Aydin Sanda, Murad

    2010-12-01

    In this study, fatty acid compositions of six Centaurea species growing in the Konya region were determined. The fatty acid composition of Centaurea balsamita, Centaurea calolepis, Centaurea carduiformis subsp. carduiformis, Centaurea cariensis subsp. maculiceps, C. cariensis subsp. microlepis and Centaurea iberica were analysed. Four species of these six Centaurea are endemic to Turkey. The endemic Centaurea species are C. calolepis, C. carduiformis subsp. carduiformis, C. cariensis subsp. maculiceps and C. cariensis subsp. microlepis. Generally, C 18:2 ω6 linoleic acid, C 16:0 palmitic acid, C 18:3 ω3 linolenic acid and C 18:1 oleic acid were found to be the major fatty acids in all species. Polyunsaturated fatty acids (PUFAs) were found in higher amounts than saturated fatty acids and monounsaturated fatty acids in all species. PUFAs were determined at 55.10%, 50.25%, 51.41%, 41.02%, 46.18% and 58.80% in C. balsamita, C. calolepis, C. carduiformis subsp. carduiformis, C. cariensis subsp. maculiceps, C. cariensis subsp. microlepis and C. iberica, respectively. PMID:21108113

  10. Mass algal culture system

    DOEpatents

    Raymond, Lawrence P.

    1982-01-01

    An apparatus and process for the culture of algae in a liquid medium is disclosed. The medium circulates through an open trough and is exposed to an atmosphere which is temperature regulated. The nutrient content of the liquid medium is regulated to control the chemical composition growth and reproduction characteristics of the cultured algae. Before it is allowed to strike the medium, sunlight is passed through a filter to remove wavelengths which are not photosynthetically active. Heat energy can be recovered from the filter.

  11. Mass algal culture system

    DOEpatents

    Raymond, Lawrence P.

    1981-01-01

    An apparatus and process for the culture of algae in a liquid medium is disclosed. The medium circulates through an open trough and is exposed to an atmosphere which is temperature regulated. The nutrient content of the liquid medium is regulated to control the chemical composition growth and reproduction characteristics of the cultured algae. Before it is allowed to strike the medium, sunlight is passed through a filter to remove wavelengths which are not photosynthetically active. Heat energy can be recovered from the filter.

  12. Plankton studies in San Francisco Bay; II, Phytoplankton abundance and species composition, July 1977-December 1979

    USGS Publications Warehouse

    Wong, Raymond L. J.; Cloern, James E.

    1981-01-01

    Data are presented on the phytoplankton species composition and abundance in San Francisco Bay from July 1977 through December 1979. Phytoplankton identification and enumerations were made at selected stations. Sample collections were made at selected stations in the main channel of the Bay from Rio Vista on the Sacramento River to Calaveras Point in South San Francisco Bay, and at shoal stations in the central portion of South San Francisco Bay, San Pablo Bay, and Suisun Bay. Also reported, from October 1978 through December 1979, are the calculated phytoplankton carbon and percent nondiatom carbon, and the species list. This study is one component of an ongoing interdisciplinary study of San Francisco Bay. (USGS)

  13. Understanding how seasonality and shifts in species composition impact emission estimates in semi-arid ecosystems

    NASA Astrophysics Data System (ADS)

    Sparks, A. M.; Yokelson, R. J.; Smith, A. M.; Marshall, J. D.; Tinkham, W.

    2013-12-01

    The importance of wildland fire as a source of trace gas emissions to the atmosphere has been demonstrated in the scientific literature and through numerous NASA funded campaigns to further understand the drivers and impacts of these emissions (e.g., SAFARI 1992, SAFARI 2000, TRACE A, etc). Most studies quantify emissions using remotely sensed data through multiplying the area burned, the quantity of fuel combusted, and the emission factors of a given gas species (EFX, grams of gas, X, emitted per kilogram of fuel consumed). The latter is known to exhibit considerable uncertainty and indeed a prior study as part of NASA's SAFARI 2000 campaign highlighted a seasonal dependence of carbonaceous gas species emissions. In this study, rangeland grass and shrub species were collected periodically from northern Great Basin shrub-steppe ecosystems during the typical burn season and burned in a small-scale laboratory setup where major carbonaceous and nitrogenous emission species were monitored and measured. Preliminary results indicate that emission factors of several major gas species, including carbon monoxide and nitrogen oxides, vary considerably over the course of a season. Large differences in emission apportionment between the rangeland species also suggests that shifting vegetation composition (via replacement of native with invasive species) can have a significant influence on emissions from semi-arid ecosystems. Further development of this data could lead to an enhanced understanding of how emission factors vary seasonally and how total emissions change with major vegetation shifts in other ecosystems.

  14. Fatty-Acid Composition of Seeds and Chemotaxonomic Evaluation of Sixteen Sapindaceae Species.

    PubMed

    Coutinho, Diogenes J Gusmão; Barbosa, Mariana O; Silva, Rejane M; da Silva, Suzene I; de Oliveira, Antonio Fernando M

    2015-08-01

    Circumscriptions for the Sapindaceae family and its infrafamilial relationships have been widely discussed. Certain groups are highly morphologically similar; thus, it is difficult to identify certain taxa. DNA Analyses have also indicated complex phylogenetic relationships, and it is difficult to relate such analyses to morphological data. Given the above concerns, this study aimed to investigate the fatty-acid profiles of the seed oils of 16 Sapindaceae species belonging to five tribes and to evaluate their potential chemotaxonomic significance. In total, eleven fatty acids were identified, and eicosenoic acid predominated in nine species. Multivariate analyses (principal component and cluster analyses) of the fatty-acid profiles of the seed oils allowed to separate them in two major clusters. The first cluster, characterized by oils with high eicosenoic acid levels, included all species belonging to the Paullinieae tribe (Cardiospermum, Paullinia, and Serjania species). In the second main cluster, the chemical similarity of the oils was lower, and the species belonged to different tribes. Nevertheless, the tree investigated Allophylus species (Thouinieae tribe) constituted a separate subcluster. Thus, the results showed that the fatty-acid composition of the seed oils of Sapindaceae species provide chemotaxonomic support for the separation of the Paullinieae tribe from the other tribes studied. PMID:26265579

  15. Rapid plant evolution in the presence of an introduced species alters community composition.

    PubMed

    Smith, David Solance; Lau, Matthew K; Jacobs, Ryan; Monroy, Jenna A; Shuster, Stephen M; Whitham, Thomas G

    2015-10-01

    Because introduced species may strongly interact with native species and thus affect their fitness, it is important to examine how these interactions can cascade to have ecological and evolutionary consequences for whole communities. Here, we examine the interactions among introduced Rocky Mountain elk, Cervus canadensis nelsoni, a common native plant, Solidago velutina, and the diverse plant-associated community of arthropods. While introduced species are recognized as one of the biggest threats to native ecosystems, relatively few studies have investigated an evolutionary mechanism by which introduced species alter native communities. Here, we use a common garden design that addresses and supports two hypotheses. First, native S. velutina has rapidly evolved in the presence of introduced elk. We found that plants originating from sites with introduced elk flowered nearly 3 weeks before plants originating from sites without elk. Second, evolution of S. velutina results in a change to the plant-associated arthropod community. We found that plants originating from sites with introduced elk supported an arthropod community that had ~35 % fewer total individuals and a different species composition. Our results show that the impacts of introduced species can have both ecological and evolutionary consequences for strongly interacting species that subsequently cascade to affect a much larger community. Such evolutionary consequences are likely to be long-term and difficult to remediate. PMID:26062439

  16. Enhanced Production of Green Tide Algal Biomass through Additional Carbon Supply

    PubMed Central

    de Paula Silva, Pedro H.; Paul, Nicholas A.; de Nys, Rocky; Mata, Leonardo

    2013-01-01

    Intensive algal cultivation usually requires a high flux of dissolved inorganic carbon (Ci) to support productivity, particularly for high density algal cultures. Carbon dioxide (CO2) enrichment can be used to overcome Ci limitation and enhance productivity of algae in intensive culture, however, it is unclear whether algal species with the ability to utilise bicarbonate (HCO3−) as a carbon source for photosynthesis will benefit from CO2 enrichment. This study quantified the HCO3− affinity of three green tide algal species, Cladophora coelothrix, Cladophora patentiramea and Chaetomorpha linum, targeted for biomass and bioenergy production. Subsequently, we quantified productivity and carbon, nitrogen and ash content in response to CO2 enrichment. All three species had similar high pH compensation points (9.7–9.9), and grew at similar rates up to pH 9, demonstrating HCO3− utilization. Algal cultures enriched with CO2 as a carbon source had 30% more total Ci available, supplying twenty five times more CO2 than the control. This higher Ci significantly enhanced the productivity of Cladophora coelothrix (26%), Chaetomorpha linum (24%) and to a lesser extent for Cladophora patentiramea (11%), compared to controls. We demonstrated that supplying carbon as CO2 can enhance the productivity of targeted green tide algal species under intensive culture, despite their clear ability to utilise HCO3−. PMID:24324672

  17. Algal taxonomy forum: Algal Taxonomist, Let Serendipity Reign!

    PubMed

    Druehl, Louis

    2013-04-01

    The publication of a mini-review by Olivier De Clerck et al. in this issue of the Journal of Phycology presented an opportunity to open a dialogue on challenges faced by contemporary algal taxonomists. The Editorial Office solicited the following two additional contributions in response to De Clerck et al.'s paper; the responses were edited solely for clarity, space and format. PMID:27008510

  18. Algal turf scrubber (ATS) floways on the Great Wicomico River, Chesapeake Bay: productivity, algal community structure, substrate and chemistry(1).

    PubMed

    Adey, Walter H; Laughinghouse, H Dail; Miller, John B; Hayek, Lee-Ann C; Thompson, Jesse G; Bertman, Steven; Hampel, Kristin; Puvanendran, Shanmugam

    2013-06-01

    Two Algal Turf Scrubber (ATS) units were deployed on the Great Wicomico River (GWR) for 22 months to examine the role of substrate in increasing algal productivity and nutrient removal. The yearly mean productivity of flat ATS screens was 15.4 g · m(-2)  · d(-1) . This was elevated to 39.6 g · m(-2)  · d(-1) with a three-dimensional (3-D) screen, and to 47.7 g · m(-2)  · d(-1) by avoiding high summer harvest temperatures. These methods enhanced nutrient removal (N, P) in algal biomass by 3.5 times. Eighty-six algal taxa (Ochrophyta [diatoms], Chlorophyta [green algae], and Cyan-obacteria [blue-green algae]) self-seeded from the GWR and demonstrated yearly cycling. Silica (SiO2 ) content of the algal biomass ranged from 30% to 50% of total biomass; phosphorus, nitrogen, and carbon content of the total algal biomass ranged from 0.15% to 0.21%, 2.13% to 2.89%, and 20.0% to 25.7%, respectively. Carbohydrate content (at 10%-25% of AFDM) was dominated by glucose. Lipids (fatty acid methyl ester; FAMEs) ranged widely from 0.5% to 9% AFDM, with Omega-3 fatty acids a consistent component. Mathematical modeling of algal produ-ctivity as a function of temperature, light, and substrate showed a proportionality of 4:3:3, resp-ectively. Under landscape ATS operation, substrate manipulation provides a considerable opportunity to increase ATS productivity, water quality amelioration, and biomass coproduction for fertilizers, fermentation energy, and omega-3 products. Based on the 3-D prod-uctivity and algal chemical composition demonstrated, ATS systems used for nonpoint source water treat-ment can produce ethanol (butanol) at 5.8× per unit area of corn, and biodiesel at 12.0× per unit area of soy beans (agricultural production US). PMID:27007038

  19. Promotion of harmful algal blooms by zooplankton predatory activity

    PubMed Central

    Mitra, Aditee; Flynn, Kevin J

    2006-01-01

    The relationship between algae and their zooplanktonic predators typically involves consumption of nutrients by algae, grazing of the algae by zooplankton which in turn enhances predator biomass, controls algal growth and regenerates nutrients. Eutrophication raises nutrient levels, but does not simply increase normal predator–prey activity; rather, harmful algal bloom (HAB) events develop often with serious ecological and aesthetic implications. Generally, HAB species are outwardly poor competitors for nutrients, while their development of grazing deterrents during nutrient stress ostensibly occurs too late, after the nutrients have largely been consumed already by fast-growing non-HAB species. A new mechanism is presented to explain HAB dynamics under these circumstances. Using a multi-nutrient predator–prey model, it is demonstrated that these blooms can develop through the self-propagating failure of normal predator–prey activity, resulting in the transfer of nutrients into HAB growth at the expense of competing algal species. Rate limitation of this transfer provides a continual level of nutrient stress that results in HAB species exhibiting grazing deterrents protecting them from top-down control. This process is self-stabilizing as long as nutrient demand exceeds supply, maintaining the unpalatable status of HABs; such events are most likely under eutrophic conditions with skewed nutrient ratios. PMID:17148360

  20. Effect of Tetracycline Antibiotics on Performance and Microbial Community of Algal Photo-Bioreactor.

    PubMed

    Taşkan, Ergin

    2016-07-01

    Tetracycline antibiotics have been increasingly used in medical applications and have been found in wastewater treatment plants as a result of human and industrial activities. This study investigates the combined effects of tetracycline antibiotics on the performance of an algal photo-bioreactor operated under different antibiotic concentrations in the ranges of 0.25 to 30 mg/L and considers the inhibition of algal growth, carbon and nutrient removal rates, and eukaryotic and cyanobacterial algal community changes. The results indicated that increases in the concentration of tetracycline mixtures have adverse effects on the algal community and the performance of a photo-bioreactor, and the eukaryotic algae species were more sensitive to tetracycline antibiotics than were the cyanobacterial species. Cultivation tests showed that approximately 94 % growth inhibition of mixed algae occurred at 30 mg/L. PMID:26961083

  1. Walker Branch Throughfall Displacement Experiment Data Report: Site Characterization, System Performance, Weather, Species Composition, and Growth

    SciTech Connect

    Hanson, P.J.

    2001-09-04

    This numeric data package provides data sets, and accompanying documentation, on site characterization, system performance, weather, species composition, and growth for the Throughfall Displacement Experiment, which was established in the Walker Branch Watershed of East Tennessee to provide data on the responses of forests to altered precipitation regimes. The specific data sets include soil water content and potential, coarse fraction of the soil profile, litter layer temperature, soil temperature, monthly weather, daily weather, hourly weather, species composition of trees and saplings, mature tree and sapling annual growth, and relative leaf area index. Fortran and SAS{trademark} access codes are provided to read the ASCII data files. The data files and this documentation are available without charge on a variety of media and via the Internet from the Carbon Dioxide Information Analysis Center (CDIAC).

  2. Army ants in four forests: geographic variation in raid rates and species composition.

    PubMed

    O'Donnell, Sean; Lattke, John; Powell, Scott; Kaspari, Michael

    2007-05-01

    1. The New World army ants are top predators in the litter of tropical forest, but no comprehensive studies exist on variation in assemblage-wide activity and species composition. We used standardized protocols to estimate foraging raid rates and species composition of army ant communities in four Neotropical forests. The study sites spanned approximately 10 degrees latitude, with two sites each in Central and South America. 2. We recorded a total of 22 species of army ants. The four sites varied in observed and estimated species richness. Species overlap was highest between the Central American sites, and lowest between the South American sites. 3. Raid activity varied significantly among sites. Raid activity per kilometre of trail walks was over four times higher at the most active site (Sta. Maria, Venezuela) than at the least active site (Barro Colorado Island, Panama). Furthermore, each site showed a different diel pattern of activity. For example, raid activity was higher during daylight hours in Costa Rica, and higher at night in Venezuela. Raid activity relationships with ambient temperature also varied significantly among sites. 4. The overall rate of army ant raids passing through 1 m(2) plots was 0.73 raids per day, but varied among sites, from 0 raids per day (Panama) to 1.2 raids per day (Venezuela). 5. Primarily subterranean species were significantly more abundant in Venezuela, and above-ground foragers that form large swarm fronts were least abundant in Panama. The site heterogeneity in species abundance and diel activity patterns has implications for army ant symbionts, including ant-following birds, and for the animals hunted by these top predators. PMID:17439474

  3. Development and optimization of biofilm based algal cultivation

    NASA Astrophysics Data System (ADS)

    Gross, Martin Anthony

    This dissertation describes research done on biofilm based algal cultivation systems. The system that was developed in this work is the revolving algal biofilm cultivation system (RAB). A raceway-retrofit, and a trough-based pilot-scale RAB system were developed and investigated. Each of the systems significantly outperformed a control raceway pond in side-by-side tests. Furthermore the RAB system was found to require significantly less water than the raceway pond based cultivation system. Lastly a TEA/LCA analysis was conducted to evaluate the economic and life cycle of the RAB cultivation system in comparison to raceway pond. It was found that the RAB system was able to grow algae at a lower cost and was shown to be profitable at a smaller scale than the raceway pond style of algal cultivation. Additionally the RAB system was projected to have lower GHG emissions, and better energy and water use efficiencies in comparison to a raceway pond system. Furthermore, fundamental research was conducted to identify the optimal material for algae to attach on. A total of 28 materials with a smooth surface were tested for initial cell colonization and it was found that the tetradecane contact angle of the materials had a good correlation with cell attachment. The effects of surface texture were evaluated using mesh materials (nylon, polypropylene, high density polyethylene, polyester, aluminum, and stainless steel) with openings ranging from 0.05--6.40 mm. It was found that both surface texture and material composition influence algal attachment.

  4. Copepod abundance and species composition in the Eastern subtropical/tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Schnack-Schiel, Sigrid B.; Mizdalski, Elke; Cornils, Astrid

    2010-12-01

    Abundance and species composition of copepods were studied during the expedition ANT XXI/1 on a latitudinal transect in the eastern Atlantic from 34°49.5'N to 27°28.1'S between 2-20 November 2002. Stratified zooplankton tows were carried out at 19 stations with a multiple opening-closing net between 300 m water depth and the surface. Cyclopoid and calanoid copepods showed similar patterns of distribution and abundance. Oithona was the most abundant cyclopoid genus, followed by Oncaea. A total of 149 calanoid copepod species were identified. Clausocalanus was by far the most abundant genus, comprising on average about 45% of all calanoids, followed by Calocalanus (13%), Delibus (9%), Paracalanus (6%), and Pleuromamma (5%). All other genera comprised on average less than 5% each, with 40 genera less than 1%. The calanoid copepod communities were distinguished broadly in accordance with sea surface temperature, separating the subtropical from the tropical stations, and were largely determined by variation in species composition and species abundance. Nine Clausocalanus species were identified. The most numerous Clausocalanus species was C. furcatus, which on average comprised half of all adult of this genus. C. pergens, C. paululus, and C. jobei, contributed an average of 19%, 9%, and 9%, respectively. The Clausocalanus species differed markedly in their horizontal and vertical distributions: C. furcatus, C. jobei, and C. mastigophorus had widespread distributions and inhabited the upper water layers. Major differences between the species were found in abundance. C. paululus and C. arcuicornis were biantitropical and were absent or occurred in very low numbers in the equatorial zone. C. parapergens was found at all stations and showed a bimodal distribution pattern with maxima in the subtropics. C. pergens occurred in higher numbers only at the southern stations, where it replaced C. furcatus in dominance. In contrast to the widespread species, the bulk of the C

  5. Assessing variation in bacterial composition between the rhizospheres of two mangrove tree species

    NASA Astrophysics Data System (ADS)

    Gomes, Newton C. M.; Cleary, Daniel F. R.; Pires, Ana C. C.; Almeida, Adelaide; Cunha, Angela; Mendonça-Hagler, Leda C. S.; Smalla, Kornelia

    2014-02-01

    This study aimed to determine to what extent roots from the common mangrove tree species Avicennia schaueriana and Laguncularia racemosa are able to impose a selective force on the composition of sediment bacterial communities in mangrove intertidal sediments using barcoded pyrosequencing analysis of 16S rRNA gene fragments (V4 hyper-variable region). The novel results showed that root systems of A. schaueriana and L. racemosa are associated with increased bacterial dominance, lower richness and compositional shifts of sediment bacterial communities. The proportion of OTUs (operational taxonomc units) belonging to the orders Rhizobiales and Vibrionales were enriched in rhizosphere samples from both plant species and sulphur-reducing bacteria (SRB) belonging to the order Desulfobacterales and Desulfuromonadales were enriched in the rhizosphere of A. schaueriana. In addition, Clostridium and Vibrio populations were more abundant in different mangrove rhizospheres. A. schaueriana and L. racemosa roots appear to be able to impose a selective force on the composition of mangrove sediment bacterial communities and this phenomenon appears to be plant species specific. Our findings provide new insights into the potential ecological roles of bacterial guilds in plant-microbe interactions and may aid rhizoengineering approaches for replanting impacted mangrove areas.

  6. Diet composition and resource partitioning in two small flatfish species in the German Bight

    NASA Astrophysics Data System (ADS)

    Schückel, S.; Sell, A.; Kröncke, I.; Reiss, H.

    2011-10-01

    Since the late 1980s, the small-sized non-commercial flatfish species solenette ( Buglossidium luteum) and scaldfish ( Arnoglossus laterna) have increased in abundance in the southern North Sea. Because these species are considered as possible competitors for prey of commercial flatfish, this study aimed at advancing knowledge of their feeding ecology. Between January 2009 and January 2010 stomach contents of solenette and scaldfish and benthic infauna were sampled seasonally in a study area in the German Bight. The objectives were to investigate the seasonal variability of feeding activity and diet composition of both flatfish species related to benthic prey availability. For both flatfish, the highest feeding activity was found in summer, at the same time that the highest prey densities occurred in the study area. A reduced feeding activity was observed during the winter of 2010, but not in the winter of 2009, probably related to higher 2009 water temperatures. In all seasons, diet composition of solenette was dominated by meiofauna, mainly harpacticoid copepods. Macrofauna prey species, namely juveniles of bivalves and echinoderms became important in spring. An increase in amphipods and cumaceans was found in the stomach contents during summer and autumn, simultaneously with their increased abundance in the benthic infauna. In contrast, polychaetes were rarely found in the diet, but dominated the infauna during all seasons. Diet composition of scaldfish was dominated by larger and mobile prey, and, during all seasons, was mainly comprised of crustaceans. Amphipods characterised the diet in both winters, while decapods such as Crangon spp. and Liocarcinus spp. were the dominant prey from spring to autumn. Additionally, juveniles of flatfish (Pleuronectids) and bivalves were found in the scaldfish diet in spring, replaced by cumaceans in summer. No dietary overlap between both flatfish species was found across seasons, indicating partitioning of prey resources

  7. Changes in plant species composition of coastal dune habitats over a 20-year period

    PubMed Central

    Del Vecchio, Silvia; Prisco, Irene; Acosta, Alicia T. R.; Stanisci, Angela

    2015-01-01

    Coastal sandy ecosystems are increasingly being threatened by human pressure, causing loss of biodiversity, habitat degradation and landscape modifications. However, there are still very few detailed studies focussing on compositional changes in coastal dune plant communities over time. In this work, we investigated how coastal dune European Union (EU) habitats (from pioneer annual beach communities to Mediterranean scrubs on the landward fixed dunes) have changed during the last 20 years. Using phytosociological relevés conducted in 1989–90 and in 2010–12, we investigated changes in floristic composition over time. We then compared plant cover and the proportion of ruderal, alien and habitat diagnostic species (‘focal species’) in the two periods. Finally, we used Ellenberg indicator values to define the ‘preferences’ of the plant species for temperature and moisture. We found that only fore dune habitats showed significant differences in species cover between the two time periods, with higher plant cover in the more recent relevés and a significant increase in thermophilic species. Although previous studies have demonstrated consistent habitat loss in this area, we observed that all coastal dune plant communities remain well represented, after a 20-year period. However, fore dunes have been experiencing significant compositional changes. Although we cannot confirm whether the observed changes are strictly related to climatic changes, to human pressure or to both, we hypothesize that a moderate increment in average yearly temperature may have promoted the increase in plant cover and the spread of thermophilic species. Thus, even though human activities are major driving forces of change in coastal dune vegetation, at the community scale climatic factors may also play important roles. Our study draws on re-visitation studies which appear to constitute a powerful tool for the assessment of the conservation status of EU habitats. PMID:25750408

  8. The costs of evaluating species densities and composition of snakes to assess development impacts in amazonia.

    PubMed

    Fraga, Rafael de; Stow, Adam J; Magnusson, William E; Lima, Albertina P

    2014-01-01

    Studies leading to decision-making for environmental licensing often fail to provide accurate estimates of diversity. Measures of snake diversity are regularly obtained to assess development impacts in the rainforests of the Amazon Basin, but this taxonomic group may be subject to poor detection probabilities. Recently, the Brazilian government tried to standardize sampling designs by the implementation of a system (RAPELD) to quantify biological diversity using spatially-standardized sampling units. Consistency in sampling design allows the detection probabilities to be compared among taxa, and sampling effort and associated cost to be evaluated. The cost effectiveness of detecting snakes has received no attention in Amazonia. Here we tested the effects of reducing sampling effort on estimates of species densities and assemblage composition. We identified snakes in seven plot systems, each standardised with 14 plots. The 250 m long centre line of each plot followed an altitudinal contour. Surveys were repeated four times in each plot and detection probabilities were estimated for the 41 species encountered. Reducing the number of observations, or the size of the sampling modules, caused significant loss of information on species densities and local patterns of variation in assemblage composition. We estimated the cost to find a snake as $ 120 U.S., but general linear models indicated the possibility of identifying differences in assemblage composition for half the overall survey costs. Decisions to reduce sampling effort depend on the importance of lost information to target-issues, and may not be the preferred option if there is the potential for identifying individual snake species requiring specific conservation actions. However, in most studies of human disturbance on species assemblages, it is likely to be more cost-effective to focus on other groups of organisms with higher detection probabilities. PMID:25147930

  9. Grazing effects on species composition in different vegetation types (La Palma, Canary Islands)

    NASA Astrophysics Data System (ADS)

    Arévalo, J. R.; de Nascimento, L.; Fernández-Lugo, S.; Mata, J.; Bermejo, L.

    2011-05-01

    Grazing management is probably one of the most extensive land uses, but its effects on plant communities have in many cases been revealed to be contradictory. Some authors have related these contradictions to the stochastic character of grazing systems. Because of that, it is necessary to implement specific analyses of grazing effects on each community, especially in natural protected areas, in order to provide the best information to managers. We studied the effects of grazing on the species composition of the main vegetation types where it takes place (grasslands, shrublands and pine forests) on the island of La Palma, Canary Islands. We used the point-quadrat intersect method to study the species composition of grazed and ungrazed areas, which also were characterized by their altitude, distance to farms, distance to settlements, year of sampling, herbaceous aboveground biomass and soil organic matter. The variables organic matter, productivity and species richness were not significantly affected by grazing. The species composition of the analyzed plant communities was affected more by variables such as altitude or distance to farms than by extensive grazing that has been traditionally carried out on the island of La Palma involving certain practices such as continuous monitoring of animals by goat keepers, medium stocking rates adjusted to the availability of natural pastures, supplementation during the dry season using local forage shrubs or mown pastures and rotating animals within grazing areas Although some studies have shown a negative effect of grazing on endangered plant species, these results cannot be freely extrapolated to the traditional grazing systems that exert a low pressure on plant communities (as has been found in this study). We consider extensive grazing as a viable way of ensuring sustainable management of the studied ecosystems.

  10. The Costs of Evaluating Species Densities and Composition of Snakes to Assess Development Impacts in Amazonia

    PubMed Central

    de Fraga, Rafael; Stow, Adam J.; Magnusson, William E.; Lima, Albertina P.

    2014-01-01

    Studies leading to decision-making for environmental licensing often fail to provide accurate estimates of diversity. Measures of snake diversity are regularly obtained to assess development impacts in the rainforests of the Amazon Basin, but this taxonomic group may be subject to poor detection probabilities. Recently, the Brazilian government tried to standardize sampling designs by the implementation of a system (RAPELD) to quantify biological diversity using spatially-standardized sampling units. Consistency in sampling design allows the detection probabilities to be compared among taxa, and sampling effort and associated cost to be evaluated. The cost effectiveness of detecting snakes has received no attention in Amazonia. Here we tested the effects of reducing sampling effort on estimates of species densities and assemblage composition. We identified snakes in seven plot systems, each standardised with 14 plots. The 250 m long centre line of each plot followed an altitudinal contour. Surveys were repeated four times in each plot and detection probabilities were estimated for the 41 species encountered. Reducing the number of observations, or the size of the sampling modules, caused significant loss of information on species densities and local patterns of variation in assemblage composition. We estimated the cost to find a snake as $ 120 U.S., but general linear models indicated the possibility of identifying differences in assemblage composition for half the overall survey costs. Decisions to reduce sampling effort depend on the importance of lost information to target-issues, and may not be the preferred option if there is the potential for identifying individual snake species requiring specific conservation actions. However, in most studies of human disturbance on species assemblages, it is likely to be more cost-effective to focus on other groups of organisms with higher detection probabilities. PMID:25147930

  11. Algal biofuels: challenges and opportunities.

    PubMed

    Leite, Gustavo B; Abdelaziz, Ahmed E M; Hallenbeck, Patrick C

    2013-10-01

    Biodiesel production using microalgae is attractive in a number of respects. Here a number of pros and cons to using microalgae for biofuels production are reviewed. Algal cultivation can be carried out using non-arable land and non-potable water with simple nutrient supply. In addition, algal biomass productivities are much higher than those of vascular plants and the extractable content of lipids that can be usefully converted to biodiesel, triacylglycerols (TAGs) can be much higher than that of the oil seeds now used for first generation biodiesel. On the other hand, practical, cost-effective production of biofuels from microalgae requires that a number of obstacles be overcome. These include the development of low-cost, effective growth systems, efficient and energy saving harvesting techniques, and methods for oil extraction and conversion that are environmentally benign and cost-effective. Promising recent advances in these areas are highlighted. PMID:23499181

  12. Chemical composition of the essential oil from Croton kimosorum, an endemic species to Madagascar.

    PubMed

    Rabehaja, Delphin J R; Ihandriharison, Harilala; Ramanoelina, Panja A R; Benja, Rakotonirina; Ratsimamanga-Urverg, Suzanne; Bighelli, Ange; Casanova, Joseph; Tomi, Félix

    2014-01-01

    Croton kimosorum Leandri is an endemic species to Madagascar. The chemical composition of aerial parts, leaf and stem oils is reported for the first time. Analysis was carried out by combination of chromatographic (CC, GC), spectroscopic and spectrometric (MS, 13C NMR) techniques. In total, 76 compounds have been identified. Essential oil isolated from aerial parts contained mainly linalool (21.6%), sabinene (10.4%), 1,8-cineole (6.3%), beta-pinene (6.2%), (E)-beta-caryophyllene (5.9%), terpinen-4-ol (4.8%), geraniol (4,5%) and germacrene D (2.3%). In comparison with the first sample, the composition of leaf and stem oils varied slightly, while essential oil isolated by vapor distillation from a semi-industrial still exhibited similar composition. PMID:24660481

  13. Dynamics of Tree Species Composition in Temperate Mountains of South Korea over Fourteen Years using 880 Permanent Plots

    NASA Astrophysics Data System (ADS)

    Lee, B.; Kim, H. S.; Park, J.; Moon, M.; Cho, S.; Ryu, D.; Wynn, K. Z.; Park, J.

    2014-12-01

    The structure of forest and diversity of tree species in temperate mountains have been influenced by changing climate conditions as well as successional changes. To understand how tree species composition and stand structure change across temperate mountains, the species composition, size, and environmental information were collected over the past fourteen years in 880 quadrats of 20 m x 50 m of woodland communities distributed across Jiri and Baekoon Mountains, South Korea. The preliminary investigation on variations of tree species revealed that overall composition of tree species increased in terms of both diversity and biomass growth of tree species, reflecting fast and wide changes in temperate forests of Korea. Among dominant trees, the Quercus mongolica, Styrax japonicu, and Acer pseudosieboldianum recorded the highest increase in stand density, implying the most prosperous species under current conditions, while the species of Quercus variabilis and Fraxinus mandshurica appeared as fast declining species in the number. In terms of biomass growth of dominant species, the Stewartia pseudocamellia showed the largest increase of biomass, followed by Quercus serrata and Quercus mongolica., while the Fraxinus mandshurica appeared to have a rapid decline, followed by Alnus japonica and Quercus dentata. Overall, the fast change of composition in tree species is clear and further analysis to clarify the reasons for such fast and species-specific changes is underway especially to separate the effect of successional change and climate change.

  14. Amatoxin and phallotoxin composition in species of the genus Amanita in Colombia: a taxonomic perspective.

    PubMed

    Vargas, N; Bernal, A; Sarria, V; Franco-Molano, A; Restrepo, S

    2011-11-01

    Some species in the genus Amanita have a great variety of toxic secondary metabolites. They are characterized macroscopically by having a white spore print and free gills, and microscopically by the presence of a divergent hymenophoral trama. Some species of Amanita present in Colombia were chemically characterized by analyzing their toxin composition using HPLC. Samples were collected in oak (Quercus humboldtii) and pine (Pinus radiata) forests. Twelve species were recovered, Amanita fuligineodisca, Amanita xylinivolva, Amanita flavoconia, Amanita rubescens, Amanita bisporigera, Amanita muscaria, Amanita humboldtii, Amanita sororcula, Amanita brunneolocularis, Amanita colombiana, Amanita citrina, Amanita porphyria as well as two unreported species. Results showed that most of the analyzed species have α -amanitin in concentrations ranging from 50 ppm to 6000 ppm. Concentrations of α-amanitin in the pileus were significantly greater than in the stipe. Phalloidin and phallacidin were only present in A. bisporigera. Chromatographic profiles are proposed as an additional taxonomic tool since specific peaks with similar retention times were conserved at the species level. PMID:21945592

  15. STUDIES ON THE SPECIES COMPOSITION AND RELATIVE ABUNDANCE OF MOSQUITOES OF MPIGI DISTRICT, CENTRAL UGANDA

    PubMed Central

    Mayanja, Martin; Mutebi, John-Paul; Crabtree, Mary B.; Ssenfuka, Fred; Muwawu, Teddy; Lutwama, Julius J.

    2015-01-01

    Prediction of arboviral disease outbreaks and planning for appropriate control interventions require knowledge of the mosquito vectors involved. Although mosquito surveys have been conducted in different regions of Uganda since the mid 30’s such studies have not been carried out in Mpigi District. In October 2011, we conducted mosquito collections in Mpigi district to determine species composition and relative abundance of the different species. The survey was conducted in four villages, Njeru, Ddela, Kiwumu and Nsumbain Kammengo sub-county, Mpigi district, Uganda. CDC light traps baited with dry ice (carbon dioxide) were used to capture adult mosquitoes. A total of 54,878 mosquitoes comprising 46 species from eight genera were collected. The dominant species at all sites was Coquilletidia (Coquilletidia) fuscopennata Theobald (n=38,059, 69%), followed by Coquillettidia (Coquillettidia) metallica Theobald (n=4,265, 7.8%). The number of species collected varied from 17 in the genus Culex to 1 in the genus Lutzia. Of the 46 species identified, arboviruses had previously been isolated from 28 (60.9%) suggesting a high potential for arboviral transmission and/or maintenance in Mpigi District. PMID:26346305

  16. Positional-Species Composition of Diacylglycerol Acetates from Mature Euonymus Seeds.

    PubMed

    Sidorov, Roman A; Pchelkin, Vasily P; Zhukov, Anatoly V; Tsydendambaev, Vladimir D

    2016-06-01

    The positional-species composition (PSC) of 3-acetyl-1,2-diacyl-sn-glycerols (AcDAGs) from the seeds of mature fruits of 14 species of the genus Euonymus L. was established. The residues of six major fatty acids (FAs), palmitic (P), stearic (St), hexadecenoic (H), octadecenoic (O), linoleic (L), and linolenic (Ln), were present in the AcDAGs. Here, we demonstrated that the profile of PSC of AcDAGs could serve as chemotaxonomic factor to divide euonymus species studied here into groups which completely correlate with the present day systematic of the genus. In particular, the Euonymus section greatly exceeded other sections of the Euonymus subgenus as well as the Kalonymus one in the total levels of AcDAGs positional species having one and two O residues and was characterized by significantly lesser concentrations of species with one and two L residues. Moreover, in seed, AcDAGs of almost all Euonymus species EFL values were slightly higher than EFO ones, but all EFL and EFO values were higher than 1.0, and therefore, it can be concluded that both FAs mainly esterified sn-2-position of the glycerol moiety and saturated FAs residues were always virtually absent in the sn-2 position of Euonymus seed AcDAGs, as it is also the case in nearly all TAGs molecules of plant origin. PMID:27151557

  17. The Prevalence and Species Composition of Malassezia yeasts in Patients with Clinically Suspected Onychomycosis

    PubMed Central

    Prohic, Asja; Kuskunovic-Vlahovljak, Suada; Sadikovic, Tamara Jovovic; Cavaljuga, Semra

    2015-01-01

    Introduction: There are limited numbers of studies which focused on the identification of Malassezia yeasts to a species level in onychomycosis. Therefore, the aim of our study was to determine the prevalence and species composition of Malassezia yeasts in patients with clinically suspected onychomycosis and to examine if the range of species varies with patient gender, age, site of involvement and clinical pattern of onychomycosis. Methods: Specimens were taken from 785 patients presenting signs of onychomycosis and then incubated on Sabouraud dextrose agar and modified Dixon agar. The yeasts isolated were identified according to their macroscopic and microscopic features and physiological characteristics. Results: Malassezia species were diagnosed both by microscopy and culture in fourteen (1.8%) patients. M. globosa was the predominant, if not only, species identified from nail samples. Mixed cultures were observed in five cases: in 4 cases Malassezia was co-isolated with Candida albicans and in one case with dermatophyte. Fingernails were affected more frequently than toenails (85.7%) and distolateral subungual onychomycosis was the most common clinical type (78.6%). Conclusion: No significant differences were found in the distribution of Malassezia species isolated according to demographic parameters. PMID:26005253

  18. Composition at different development stages of the essential oil of four Achillea species grown in Iran.

    PubMed

    Azizi, Majid; Chizzola, Remigius; Ghani, Askar; Oroojalian, Fatemeh

    2010-02-01

    Four Achillea species, A. millefolium, A. nobilis, A. eriophora and A. biebersteinii, were grown in small field plots in Iran and harvested at four developmental stages: vegetative, at the appearance of the first flower heads, at full flowering, and at late flowering. The composition of the main volatile compounds in dichloromethane extracts and the essential oil obtained by microdistillation was established by GC/MS and GC. 1,8-Cineole (27-41%) was the main compound in the oils from A. millefolium and A. biebersteinii. These two species reached the highest amount of volatile compounds at the full blooming stage. alpha-Thujone was the main compound in A. nobilis oil (25-64%). Fully blooming plants of this species also had a high proportion of artemisia ketone (up to 40%) in the oil. The main oil compounds of A. eriophora were camphor (about 35%) and 1,8-cineol (about 30%). This species produces only a small number of flower heads and the composition of the essential oil did not change during development. PMID:20334145

  19. Response of soil microbial community composition to afforestation with pure and mixed tree species

    NASA Astrophysics Data System (ADS)

    Gunina, Anna; Smith, Andrew; Godbold, Douglas; Kuzyakov, Yakov; Jones, Davey

    2016-04-01

    Afforestation of agricultural land affects soil ecosystem functions by inducing carbon (C) and nitrogen (N) sequestration and promoting shifts in microbial community structure. Soil C and N stocks undergo progressive changes over several decades after forest establishment, particularly in successional forests. In contrast, microbial community structure can be shifted already in the first decade and thus, direct effect of tree species can be revealed. Thus, the aim of this study was to determine how soil microbial community composition is altered by afforestation with either one, two or three species mixtures of trees, which possess strongly contrasting functional traits. The study was conducted at the BangorDIVERSE temperate forest experiment established in 2004 on a former arable soil. Soil samples were collected under single, two and three species mixtures of alder, birch, beech and oak, while contiguous field was chosen as a control. Soil samples were analysed for key quality indicators (total C and N, pH, nitrate and ammonium), and microbial community structure was determined by phospholipid fatty acids (PLFAs) analysis. Ten years after afforestation, total soil C, N and C/N ratios were not strongly affected, with the highest positive changes (up to 20%) for the birch, alder+oak and birch+beech plots. Decrease of C and N contents were observed for the pure beech plot. pH decreased by 1-1.2 units for all forest plots compare to the control soil. Total PLFAs content (370-630 nmol g‑1 soil) increased in comparison to the control (315 nmol g‑1 soil), resulting in the changes in total PLFAs content from 20 to 100%. Thus, changes of chemical properties (C, N) occur slower than changes of microbial biomarkers at the early stage of afforestation. Bacterial PLFA content was shifted by 20-120%, whereas fungal PLFAs were changed by 50-300%, reflecting stronger impact of afforestation on the recovery of fungal communities than on bacterial. Principal component analysis

  20. Bumble Bees (Hymenoptera: Apidae: Bombus spp.) of Interior Alaska: Species Composition, Distribution, Seasonal Biology, and Parasites

    PubMed Central

    Pampell, Rehanon; Pantoja, Alberto; Holloway, Patricia; Knight, Charles; Ranft, Richard

    2015-01-01

    Abstract Background Despite the ecological and agricultural significance of bumble bees in Alaska, very little is known and published about this important group at the regional level. The objectives of this study were to provide baseline data on species composition, distribution, seasonal biology, and parasites of the genus Bombus at three major agricultural locations within Alaska: Fairbanks, Delta Junction, and Palmer, to lay the groundwork for future research on bumble bee pollination in Alaska. New information A total of 8,250 bumble bees representing 18 species was collected from agricultural settings near Delta Junction, Fairbanks, and Palmer, Alaska in 2009 and 2010. Of the 8,250 specimens, 51% were queens, 32.7% were workers, and 16.2% were males. The species composition and relative abundances varied among sites and years. Delta Junction had the highest relative abundance of bumble bees, representing 51.6% of the specimens collected; the other two locations, Fairbanks and Palmer represented 26.5% and 21.8% of the overall catch respectively. The species collected were: Bombus bohemicus Seidl 1837 (= B. ashtoni (Cresson 1864)), B. balteatus Dahlbom 1832, B. bifarius Cresson 1878, B. centralis Cresson 1864, B. cryptarum (Fabricius 1775) (=B. moderatus Cresson 1863), B. distinguendus Morawitz 1869, B. flavidus Eversmann 1852 (=B. fernaldae Franklin 1911), B. flavifrons Cresson 1863, B. frigidus Smith 1854, B. insularis (Smith 1861), B. jonellus (Kirby 1802), B. melanopygus Nylander 1848, B. mixtus Cresson 1878, B. neoboreus Sladen 1919, B. occidentalis Greene 1858, B. perplexus Cresson 1863, B. rufocinctus Cresson 1863, and B. sylvicola Kirby 1837. Overall, the most common bumble bees near agricultural lands were B. centralis, B. frigidus, B. jonellus, B. melanopygus, B. mixtus, and B. occidentalis. Species' relative population densities and local diversity were highly variable from year to year. Bombus occidentalis, believed to be in decline in the Pacific

  1. USE OF DETRENDED CORRESPONDENCE ANALYSIS IN EVALUATING FACTORS CONTROLLING SPECIES COMPOSITION OF PERIPHYTON.

    USGS Publications Warehouse

    Leland, Harry V.; Carter, James L.

    1986-01-01

    Detrended correspondence analysis (DCA) was evaluated for its usefulness in elucidating relationships among samples and among species of periphyton in an oligotrophic stream, and for its effectiveness in displaying major gradients where an experimental gradient (copper) affecting species composition was imposed. It was highly sensitive to differences among samples and consistently provided ecologically meaningful species ordinations. Gradients related to seasonality of taxa and year-to-year differences in population densities were evident in DCA ordinations if data for all sampling dates were included, and these gradients complicated interpretation of the copper gradient. Stage of succession was a secondary gradient during exposure and complicated interpretation of the copper gradient after a major disturbance event (flooding).

  2. Species Composition of Bacterial Communities Influences Attraction of Mosquitoes to Experimental Plant Infusions

    PubMed Central

    Ponnusamy, Loganathan; Wesson, Dawn M.; Arellano, Consuelo; Schal, Coby

    2013-01-01

    In the container habitats of immature mosquitoes, catabolism of plant matter and other organic detritus by microbial organisms produces metabolites that mediate the oviposition behavior of Aedes aegypti and Aedes albopictus. Public health agencies commonly use oviposition traps containing plant infusions for monitoring populations of these mosquito species, which are global vectors of dengue viruses. In laboratory experiments, gravid females exhibited significantly diminished responses to experimental infusions made with sterilized white oak leaves, showing that attractive odorants were produced through microbial metabolic activity. We evaluated effects of infusion concentration and fermentation time on attraction of gravid females to infusions made from senescent bamboo or white oak leaves. We used plate counts of heterotrophic bacteria, total counts of 4′,6-diamidino-2-phenylindole-stained bacterial cells, and 16S ribosomal DNA (rDNA) polymerase chain reaction–denaturing gradient gel electrophoresis (DGGE) to show that changes in the relative abundance of bacteria and the species composition of bacterial communities influenced attraction of gravid A. aegypti and A. albopictus mosquitoes to infusions. DGGE profiles showed that bacterial species composition in infusions changed over time. Principal components analysis indicated that oviposition responses to plant infusions were in general most affected by bacterial diversity and abundance. Analysis of bacterial 16S rDNA sequences derived from DGGE bands revealed that Proteo-bacteria (Alpha-, Beta-, Delta-, and Gamma-) were the predominant bacteria detected in both types of plant infusions. Gravid A. aegypti were significantly attracted to a mix of 14 bacterial species cultured from bamboo leaf infusion. The oviposition response of gravid mosquitoes to plant infusions is strongly influenced by abundance and diversity of bacterial species, which in turn is affected by plant species, leaf biomass, and fermentation

  3. Combined effect of predatory zooplankton and allelopathic aquatic macrophytes on algal suppression.

    PubMed

    Zuo, Shengpeng; Wan, Kun; Ma, Sumin

    2015-01-01

    The present study evaluated the combined effects of four typical predatory zooplankton and allelopathic aquatic macrophytes on algal control in a microcosm system. It would determine the effects of diverse species and biological restoration on the growth of harmful water-bloom microalgae in great lakes polluted by excess nutrients. It was found that the mixtures of each zooplankton and the floating plant Nymphoides peltatum had stronger inhibitory effects on harmful water-bloom microalgae than the individual species in clean or eutrophic water bodies. In addition, a community of four zooplankton types had a synergistic effect on algal inhibition. Algal suppression by the zooplankton community was enhanced significantly when the macrophyte was co-cultured in the microcosm. Furthermore, Chlorella pyrenoidosa was more susceptible than Microcystis aeruginosa when exposed to grazing by zooplankton and the allelopathic potential of the macrophyte. Algal inhibition was also weaker in eutrophic conditions compared with the control. These findings indicate that diverse species may enhance algal inhibition. Therefore, it is necessary to restore biological diversity and rebuild an ecologically balanced food chain or web to facilitate the control of harmful algal blooms in eutrophic lakes. PMID:25409583

  4. Relationships between pigment composition variation and reflectance for plant species from a coastal savannah in California

    NASA Technical Reports Server (NTRS)

    Ustin, Susan L.; Sanderson, Eric W.; Grossman, Yaffa; Hart, Quinn J.

    1993-01-01

    Advances in imaging spectroscopy have indicated that remotely sensed reflectance measurements of the plant canopy may be used to identify and qualify some classes of canopy biochemicals; however, the manner in which differences in biochemical compositions translate into differences is not well understood. Most frequently, multiple linear regression routines have been used to correlate narrow band reflectance values with measured biochemical concentrations. Although some success has been achieved with such methods for given data sets, the bands selected by multiple regression are not consistent between data sets, nor is it always clear what physical or biological basis underlies the correlation. To examine the relationship between biochemical concentration and leaf reflectance signal we chose to focus on the visible spectrum where the primary biochemical absorbances are due to photosynthetic pigments. Pigments provide a range of absorbance features, occur over a range of concentrations in natural samples, and are ecophysiologically important. Concentrations of chlorophyll, for example, have been strongly correlated to foliar nitrogen levels within a species and to photosynthetic capacity across many species. In addition pigments effectively absorb most of the photosynthetically active radiation between 400-700 nm, a spectral region for which silicon detectors have good signal/noise characteristics. Our strategy has been to sample a variety of naturally occurring species to measure leaf reflectance and pigment compositions. We hope to extend our understanding of pigment reflectance effects to interpret small overlapping absorbances of other biochemicals in the infrared region. For this reason, selected samples were also tested to determine total nitrogen, crude protein, cellulose, and lignin levels. Leaf reflectance spectra measured with AVIRIS bandwidths and wavelengths were compared between species and within species and for differences between seasons, for changes

  5. Comparison of toxicity to terrestrial plants with algal growth inhibition by herbicides

    SciTech Connect

    Garten, C.T. Jr.; Frank, M.L.

    1984-10-01

    The toxicities of 21 different herbicides to algae (Selenastrum capricornutum and Chlorella vulgaris) and to terrestrial plants (radishes, barley, and bush beans or soybeans) were compared to order to determine the feasibility of using a short-term (96-h) algal growth inhibition test for identifying chemicals having potential toxicity in a 4-week terrestrial plant bioassay. The toxicity of each test chemical, usually in combination with a commercial formulation, was evaluated at six nominal concentrations, between 0 and 100 mg/L growth medium in the algal bioassay or between 0 and 100 mg/kg substate in the terrestrial plant bioassay, in terms of both (1) the no-observed-effect concentration (NOEC), i.e., the highest concentration tested at which no significant (P < 0.05, one-sided test) reduction in algal growth rate or in terrestrial plant yield, relative to controls, was observed; and (2) the concentration at which algal growth rate or terrestrial plant yield was reduced by 50% or more relative to controls. There was generally poor agreement between results from the two types of bioassays; results from algal growth inhibition tests were not significantly correlated with results from the terrestrial plant bioassays. Overall, there was an approximately 50% chance of an algal bioassay, using Selenastrum capricornutum, successfully screening (detecting) herbicide levels that reduced terrestrial plant yield. The results indicated that algal growth inhibition tests cannot be used generically to predict phytotoxicity of herbicides to terrestrial plant species. 7 references, 14 tables.

  6. Impact of Microalgae-Bacteria Interactions on the Production of Algal Biomass and Associated Compounds

    PubMed Central

    Fuentes, Juan Luis; Garbayo, Inés; Cuaresma, María; Montero, Zaida; González-del-Valle, Manuel; Vílchez, Carlos

    2016-01-01

    A greater insight on the control of the interactions between microalgae and other microorganisms, particularly bacteria, should be useful for enhancing the efficiency of microalgal biomass production and associated valuable compounds. Little attention has been paid to the controlled utilization of microalgae-bacteria consortia. However, the studies of microalgal-bacterial interactions have revealed a significant impact of the mutualistic or parasitic relationships on algal growth. The algal growth, for instance, has been shown to be enhanced by growth promoting factors produced by bacteria, such as indole-3-acetic acid. Vitamin B12 produced by bacteria in algal cultures and bacterial siderophores are also known to be involved in promoting faster microalgal growth. More interestingly, enhancement in the intracellular levels of carbohydrates, lipids and pigments of microalgae coupled with algal growth stimulation has also been reported. In this sense, massive algal production might occur in the presence of bacteria, and microalgae-bacteria interactions can be beneficial to the massive production of microalgae and algal products. This manuscript reviews the recent knowledge on the impact of the microalgae-bacteria interactions on the production of microalgae and accumulation of valuable compounds, with an emphasis on algal species having application in aquaculture. PMID:27213407

  7. Impact of Microalgae-Bacteria Interactions on the Production of Algal Biomass and Associated Compounds.

    PubMed

    Fuentes, Juan Luis; Garbayo, Inés; Cuaresma, María; Montero, Zaida; González-Del-Valle, Manuel; Vílchez, Carlos

    2016-05-01

    A greater insight on the control of the interactions between microalgae and other microorganisms, particularly bacteria, should be useful for enhancing the efficiency of microalgal biomass production and associated valuable compounds. Little attention has been paid to the controlled utilization of microalgae-bacteria consortia. However, the studies of microalgal-bacterial interactions have revealed a significant impact of the mutualistic or parasitic relationships on algal growth. The algal growth, for instance, has been shown to be enhanced by growth promoting factors produced by bacteria, such as indole-3-acetic acid. Vitamin B12 produced by bacteria in algal cultures and bacterial siderophores are also known to be involved in promoting faster microalgal growth. More interestingly, enhancement in the intracellular levels of carbohydrates, lipids and pigments of microalgae coupled with algal growth stimulation has also been reported. In this sense, massive algal production might occur in the presence of bacteria, and microalgae-bacteria interactions can be beneficial to the massive production of microalgae and algal products. This manuscript reviews the recent knowledge on the impact of the microalgae-bacteria interactions on the production of microalgae and accumulation of valuable compounds, with an emphasis on algal species having application in aquaculture. PMID:27213407

  8. Grazing effects by Nereis diversicolor on development and growth of green algal mats

    NASA Astrophysics Data System (ADS)

    Engelsen, Anna; Pihl, Leif

    2008-08-01

    Nereis diversicolor is generally considered to be a predator and deposit feeder, but have also been found to graze on benthic algae in shallow coastal areas. In this study we investigated the grazing effects on the development and growth of green algae, Ulva spp. Algal growth was studied in an experiment including two levels of sediment thickness; 100 mm sediment including macrofauna and 5 mm sediment without macrofauna, and three treatments of varying algal biomass; sediment with propagules, sediment with low algal biomass (120 g dry weight (dwt) m - 2 ) and sediment with high algal biomass (240 g dwt m - 2 ). In the 100 mm sediment, with a natural population of macrofauna, N. diversicolor was the dominating (60% of total biomass) species. After three weeks of experimentation the result showed that N. diversicolor was able to prevent initial algal growth, affect growth capacity and also partly reduce full-grown algal mats. The weight of N. diversicolor was significantly higher for polychaetes in treatments with algae added compared to non-algal treatments. There were also indications that a rich nutrient supply per algae biomass counteracted the grazing capacity of N. diversicolor.

  9. Temporal Decay in Timber Species Composition and Value in Amazonian Logging Concessions.

    PubMed

    Richardson, Vanessa A; Peres, Carlos A

    2016-01-01

    Throughout human history, slow-renewal biological resource populations have been predictably overexploited, often to the point of economic extinction. We assess whether and how this has occurred with timber resources in the Brazilian Amazon. The asynchronous advance of industrial-scale logging frontiers has left regional-scale forest landscapes with varying histories of logging. Initial harvests in unlogged forests can be highly selective, targeting slow-growing, high-grade, shade-tolerant hardwood species, while later harvests tend to focus on fast-growing, light-wooded, long-lived pioneer trees. Brazil accounts for 85% of all native neotropical forest roundlog production, and the State of Pará for almost half of all timber production in Brazilian Amazonia, the largest old-growth tropical timber reserve controlled by any country. Yet the degree to which timber harvests beyond the first-cut can be financially profitable or demographically sustainable remains poorly understood. Here, we use data on legally planned logging of ~17.3 million cubic meters of timber across 314 species extracted from 824 authorized harvest areas in private and community-owned forests, 446 of which reported volumetric composition data by timber species. We document patterns of timber extraction by volume, species composition, and monetary value along aging eastern Amazonian logging frontiers, which are then explained on the basis of historical and environmental variables. Generalized linear models indicate that relatively recent logging operations farthest from heavy-traffic roads are the most selective, concentrating gross revenues on few high-value species. We find no evidence that the post-logging timber species composition and total value of forest stands recovers beyond the first-cut, suggesting that the commercially most valuable timber species become predictably rare or economically extinct in old logging frontiers. In avoiding even more destructive land-use patterns, managing

  10. Temporal Decay in Timber Species Composition and Value in Amazonian Logging Concessions

    PubMed Central

    Peres, Carlos A.

    2016-01-01

    Throughout human history, slow-renewal biological resource populations have been predictably overexploited, often to the point of economic extinction. We assess whether and how this has occurred with timber resources in the Brazilian Amazon. The asynchronous advance of industrial-scale logging frontiers has left regional-scale forest landscapes with varying histories of logging. Initial harvests in unlogged forests can be highly selective, targeting slow-growing, high-grade, shade-tolerant hardwood species, while later harvests tend to focus on fast-growing, light-wooded, long-lived pioneer trees. Brazil accounts for 85% of all native neotropical forest roundlog production, and the State of Pará for almost half of all timber production in Brazilian Amazonia, the largest old-growth tropical timber reserve controlled by any country. Yet the degree to which timber harvests beyond the first-cut can be financially profitable or demographically sustainable remains poorly understood. Here, we use data on legally planned logging of ~17.3 million cubic meters of timber across 314 species extracted from 824 authorized harvest areas in private and community-owned forests, 446 of which reported volumetric composition data by timber species. We document patterns of timber extraction by volume, species composition, and monetary value along aging eastern Amazonian logging frontiers, which are then explained on the basis of historical and environmental variables. Generalized linear models indicate that relatively recent logging operations farthest from heavy-traffic roads are the most selective, concentrating gross revenues on few high-value species. We find no evidence that the post-logging timber species composition and total value of forest stands recovers beyond the first-cut, suggesting that the commercially most valuable timber species become predictably rare or economically extinct in old logging frontiers. In avoiding even more destructive land-use patterns, managing

  11. Air pollutant production by algal cell cultures

    NASA Technical Reports Server (NTRS)

    Fong, F.; Funkhouser, E. A.

    1982-01-01

    The production of phytotoxic air pollutants by cultures of Chlorella vulgaris and Euglena gracilis is considered. Algal and plant culture systems, a fumigation system, and ethylene, ethane, cyanide, and nitrogen oxides assays are discussed. Bean, tobacco, mustard green, cantaloupe and wheat plants all showed injury when fumigated with algal gases for 4 hours. Only coleus plants showed any resistance to the gases. It is found that a closed or recycled air effluent system does not produce plant injury from algal air pollutants.

  12. Species Composition and Distribution of Adult Anopheles (Diptera: Culicidae) in Panama

    PubMed Central

    LOAIZA, J. R.; BERMINGHAM, E.; SCOTT, M. E.; ROVIRA, J. R.; CONN, J. E.

    2010-01-01

    Anopheles (Diptera: Culicidae) species composition and distribution were studied using human landing catch data over a 35-yr period in Panama. Mosquitoes were collected from 77 sites during 228 field trips carried out by members of the National Malaria Eradication Service. Fourteen Anopheles species were identified. The highest average human biting rates were recorded from Anopheles (Nyssorhynchus) albimanus (Wiedemann) (9.8 bites/person/night) and Anopheles (Anopheles) punctimacula (Dyar and Knab) (6.2 bites/person/night). These two species were also the most common, present in 99.1 and 74.9%, respectively, of the sites. Anopheles (Nyssorhynchus) aquasalis (Curry) was encountered mostly in the indigenous Kuna Yala Comarca along the eastern Atlantic coast, where malaria case history and average human biting rate (9.3 bites/person/night) suggest a local role in malaria transmission. An. albimanus, An. punctimacula, and Anopheles (Anopheles) vestitipennis (Dyar and Knab) were more abundant during the rainy season (May–December), whereas An. aquasalis was more abundant in the dry season (January–April). Other vector species collected in this study were Anopheles (Kerteszia) neivai (Howard, Dyar, and Knab) and Anopheles (Anopheles) pseudopunctipennis s.l. (Theobald). High diversity of Anopheles species and six confirmed malaria vectors in endemic areas of Panama emphasize the need for more detailed studies to better understand malaria transmission dynamics. PMID:18826025

  13. Composition of globoid crystals from embryo protein bodies in five species of cucurbita.

    PubMed

    Lott, J N; Vollmer, C M

    1979-02-01

    Previous energy-dispersive x-ray analysis studies of globoid crystal composition in seed protein bodies gave an indication that there might be a correlation between seed size and the type of elements stored in globoid crystals. This possibility was tested by conducting energy-dispersive x-ray analysis studies of P, K, Mg, and Ca levels in globoid crystals of four embryo regions (radicle, stem, cotyledon center palisade mesophyll, cotyledon center spongy mesophyII) in each of five different Cucurbita species (C. mixta, C. moschata, C. foetidissima, C. pepo, and C. andreana). The species were chosen to provide a range of seed size and weight. Globoid crystals from all embryo regions in all five species contained P, K, and Mg. Some variations in the levels of these elements did occur but there was no consistent pattern with regard to area of the seed or with regard to seed size. Calcium distribution showed significant variations. In species with large seeds (C. mixta, C. moschata) Ca was mainly found in globoid crystals in the radicle. Globoid crystals in species with small seeds (C. foetidissima, C. pepo, C. andreana) contained Ca in all embryo regions tested. The results of this study support the concept that Ca distribution in globoid crystals can be correlated with seed weight. PMID:16660719

  14. Composition of Globoid Crystals from Embryo Protein Bodies in Five Species of Cucurbita1

    PubMed Central

    Lott, John N. A.; Vollmer, Catherine M.

    1979-01-01

    Previous energy-dispersive x-ray analysis studies of globoid crystal composition in seed protein bodies gave an indication that there might be a correlation between seed size and the type of elements stored in globoid crystals. This possibility was tested by conducting energy-dispersive x-ray analysis studies of P, K, Mg, and Ca levels in globoid crystals of four embryo regions (radicle, stem, cotyledon center palisade mesophyll, cotyledon center spongy mesophyII) in each of five different Cucurbita species (C. mixta, C. moschata, C. foetidissima, C. pepo, and C. andreana). The species were chosen to provide a range of seed size and weight. Globoid crystals from all embryo regions in all five species contained P, K, and Mg. Some variations in the levels of these elements did occur but there was no consistent pattern with regard to area of the seed or with regard to seed size. Calcium distribution showed significant variations. In species with large seeds (C. mixta, C. moschata) Ca was mainly found in globoid crystals in the radicle. Globoid crystals in species with small seeds (C. foetidissima, C. pepo, C. andreana) contained Ca in all embryo regions tested. The results of this study support the concept that Ca distribution in globoid crystals can be correlated with seed weight. PMID:16660719

  15. Species composition and gear characteristics of the Macrobrachium fishery of the Cross River Estuary, Nigeria

    NASA Astrophysics Data System (ADS)

    Nwosu, Francis M.

    2010-03-01

    The Cross River Estuary, Nigeria, is an important shrimping area for artisanal fishermen of the coastal communities. The multi-species Macrobrachium fishery is exploited with three main gears, namely beach seine, push net and trap. Studies on species composition of this fishery recorded thirteen shrimp species, one swimming crab ( Callinectes amnicola) and two fish species ( Eleotris sp. and Pellonula leonensis). The shrimp species identified included Macrobrachium macrobrachion (83.39% and 55.69% by number and weight, respectively), M. vollenhovenii (9.66% and 37.18%), M. equidens (3.8% and 2.87%), juveniles-sub-adults of Penaeus notialis (1.11% and 1.3%), M. dux, M. felicinum, Palaemonetes africanus, Palaemon maculatus, Palaemon elegans, Desmocaris sp., Leander sp., Nematopalaemon hastatus and Alpheus pontederiae. While the selectivity index for trap was 0.25, beach seine and push net had a lower index of 0.063. The results present the first comprehensive and representative report for the Estuary shrimp fishery and will assist in the management of the biodiversity of this ecosystem.

  16. Comparison of species composition and richness of fish assemblages in altered and unaltered littoral habitats

    USGS Publications Warehouse

    Poe, T.P.; Hatcher, C.O.; Brown, C.L.; Schloesser, D.W.

    1986-01-01

    Species composition and richness of fish assemblages in altered and unaltered littoral habitats in Lake St. Clair, Michigan, differed between areas. A percid-cyprinid-cyprinodontid assemblage dominated in the unaltered area, Muscamoot Bay, which has a natural shoreline (with almost no alteration due to dredging or bulkheading), high water quality, and high species richness of aquatic macrophytes. A centrarchid assemblage dominated in the altered area, Belvidere Bay, which has a bulkheaded shoreline, many dredged areas, reduced water quality due to inputs of nutrients from a nearby river, and relatively low species richness of aquatic macrophytes. Habitat factors, species richness and abundance of aquatic macrophytes, had the most influence on fish community structure in both areas. The percid-cyprinid-cyprinodontid assemblage was significantly correlated with six species of macrophytes whereas the centrarchid assemblage was significantly correlated with only four. These patterns suggest that preference for diverse habitats was higher, and tolerance to habitat alteration lower, in percid-cyprinid-cyprinodontid assemblages than in centrarchid assemblages.

  17. Carbohydrate composition of serum low and high density lipoproteins of nonhuman primate species.

    PubMed

    Pargaonkar, P S; Radhakrishnamurthy, B; Srinivasan, S R; Berenson, G S

    1977-01-01

    1. Carbohydrate composition of serum low and high density lipoproteins obtained from 5 nonhuman primate species (chimpanzee, patas, baboon, rhesus, and spider) and humans was studied. 2. Individual lipoproteins were isolated from pooled sera of each species by ultracentrifugal flotation between the densities 1.019-1.063 for LDL-2; 1.063-1.12 for HDL-2; and 1.12-1.21 for HDL-3. After delipidation, sialic acid, fucose, glucosamine, mannose, galactose, and glucose were determined on apo LDL-2, apo HDL-2, and apo HDL-3. 3. Glucosamine, galactose, and mannose constituted a major component of the sugars in apo LDL-2, with similar relative proportions in all species. Sialic acid, fucose, and glucose formed a minor component, the proportions of which varied greatly among the species. 4. Unlike apo LDL-2, sialic acid, fucose, and glucosamine constituted the bulk of the sugars in apo HDL-2 and apo HDL-3. Mannose, galactose, and glucose were minor components, with galactose predominating. 5. Qualitative differences were observed in electrophoretic mobilities of apo HDL-2 and apo HDL-3 on polyacrylamide gel. One faster moving band was unique to chimpanzee. 6. Intraspecies differences in the content of sialic acid and fucose of apolipoproteins may be related to lipoprotein metabolism and species susceptibility (or resistance) to either spontaneous or diet-induced atherosclerosis. PMID:233783

  18. Mapping Forest Species Composition Using Imaging Spectrometry and Airborne Laser Scanner Data

    NASA Astrophysics Data System (ADS)

    Torabzadeh, H.; Morsdorf, F.; Leiterer, R.; Schaepman, M. E.

    2013-09-01

    Accurate mapping of forest species composition is an important aspect of monitoring and management planning related to ecosystem functions and services associated with water refinement, carbon sequestration, biodiversity, and wildlife habitats. Although different vegetation species often have unique spectral signatures, mapping based on spectral reflectance properties alone is often an ill-posed problem, since the spectral signature is as well influenced by age, canopy gaps, shadows and background characteristics. Thus, reducing the unknown variation by knowing the structural parameters of different species should improve determination procedures. In this study we combine imaging spectrometry (IS) and airborne laser scanning (ALS) data of a mixed needle and broadleaf forest to differentiate tree species more accurately as single-instrument data could do. Since forest inventory data in dense forests involve uncertainties, we tried to refine them by using individual tree crowns (ITC) position and shape, which derived from ALS data. Comparison of the extracted spectra from original field data and the modified one shows how ALS-derived shape and position of ITCs can improve separablity of the different species. The spatially explicit information layers containing both the spectral and structural components from the IS and ALS datasets were then combined by using a non-parametric support vector machine (SVM) classifier.

  19. Use of DNA barcoding to reveal species composition of convenience seafood.

    PubMed

    Huxley-Jones, Elizabeth; Shaw, Jennifer L A; Fletcher, Carly; Parnell, Juliette; Watts, Phillip C

    2012-04-01

    Increased education of consumers can be an effective tool for conservation of commercially harvested marine species when product labeling is accurate and allows an informed choice. However, generic labeling (e.g., as white fish or surimi) and mislabeling of seafood prevents this and may erode consumer confidence in seafood product labels in general. We used DNA barcoding to identify the species composition of two types of convenience seafood (i.e., products processed for ease of consumption): fish fingers (long pieces of fish covered with bread crumbs or batter, n = 241) and seafood sticks (long pieces of cooked fish, n = 30). In products labeled as either white fish or surimi, four teleost species were present. Less than 1.5% of fish fingers with species-specific information were mislabeled. Results of other studies show substantially more mislabeling (e.g., >25%) of teleost products, which likely reflects the lower economic gains associated with mislabeling of convenience seafood compared with whole fillets. In addition to species identification, seafood product labels should be required to contain information about, for example, harvesting practices, and our data indicate that consumers can have reasonable confidence in the accuracy of the labels of convenience seafood and thus select brands on the basis of information about current fisheries practice. PMID:22268756

  20. Translocation of microbenthic algal assemblages used for In situ analysis of metal pollution in rivers

    PubMed

    Ivorra; Hettelaar; Tubbing; Kraak; Sabater; Admiraal

    1999-07-01

    Effects of metal pollution from a zinc factory on microbenthic algal communities were assessed in three neighboring streams on the Dutch-Belgian border. Diatom species composition was experimentally related to water quality by transferring racks with colonized glass discs from a polluted stream to a reference stream and vice versa. The succession of species and the changes in biomass and metal accumulation were measured during experiments in spring, autumn, and winter. Metal concentrations and dry weight in translocated biofilms tended to conform with those in local biofilms within an incubation time of 14 to 18 days. Bray-Curtis similarity values from the different communities indicated that diatom communities responded more completely to the metal-polluted conditions than to the reference water quality. Cymbella minuta, Diatoma vulgare var. ehrenbergii, Navicula sp., and Melosira varians had a lower percentage in assemblages placed in the metal-polluted streams. In contrast, Pinnularia sp. and Neidium ampliatum decreased in assemblages from the polluted streams that were transferred to the reference stream. Achnanthes minutissima and Navicula seminulum (N. atomus) proliferated on any translocation, possibly reflecting an opportunistic strategy and a high tolerance for Zn and Cd. The behavior of the species in relation to metal pollution generally accorded with observations in the literature. However, it seems that metal tolerance is not the only selective factor, and other ecological variables may also influence the composition of microphytobenthic communities.http://link.springer-ny. com/link/service/journals/00244/bibs/37n1p19.html PMID:10341038

  1. Plant biomass and species composition along an environmental gradient in montane riparian meadows.

    PubMed

    Dwire, Kathleen A; Kauffman, J Boone; Brookshire, E N Jack; Baham, John E

    2004-04-01

    In riparian meadows, narrow zonation of the dominant vegetation frequently occurs along the elevational gradient from the stream edge to the floodplain terrace. We measured plant species composition and above- and belowground biomass in three riparian plant communities-a priori defined as wet, moist, and dry meadow-along short streamside topographic gradients in two montane meadows in northeast Oregon. The objectives were to: (1). compare above- and belowground biomass in the three meadow communities; (2). examine relations among plant species richness, biomass distribution, water table depth, and soil redox potential along the streamside elevational gradients. We installed wells and platinum electrodes along transects (perpendicular to the stream; n=5 per site) through the three plant communities, and monitored water table depth and soil redox potential (10 and 25 cm depth) from July 1997 to August 1999. Mean water table depth and soil redox potential differed significantly along the transects, and characterized a strong environmental gradient. Community differences in plant species composition were reflected in biomass distribution. Highest total biomass (live+dead) occurred in the sedge-dominated wet meadows (4311+/-289 g/m(2)), intermediate biomass (2236+/-221 g/m(2)) was seen in the moist meadow communities, dominated by grasses and sedges, and lowest biomass (1403+/-113 g/m(2)) was observed in the more diverse dry meadows, dominated by grasses and forbs. In the wet and moist communities, belowground biomass (live+dead) comprised 68-81% of the totals. Rhizome-to-root ratios and distinctive vertical profiles of belowground biomass reflected characteristics of the dominant graminoid species within each community. Total biomass was positively correlated with mean water table depth, and negatively correlated with mean redox potential (10 cm and 25 cm depths; P <0.01) and species richness ( P <0.05), indicating that the distribution of biomass coincided with the

  2. Culicoides species composition and environmental factors influencing African horse sickness distribution at three sites in Namibia.

    PubMed

    Liebenberg, Danica; Piketh, Stuart; Labuschagne, Karien; Venter, Gert; Greyling, Telane; Mienie, Charlotte; de Waal, Tania; van Hamburg, Huib

    2016-11-01

    African horse sickness (AHS) is one of the most lethal infectious, non-contagious, vector-borne disease of equids. The causative agent, African horse sickness virus (AHSV) is transmitted via Culicoides midges (Diptera: Ceratopogonidae). AHS is endemic to Namibia but detailed studies of Culicoides communities and influencing environmental parameters are limited. This study aims to determine the Culicoides species composition at three different sites and to assess environmental parameters influencing the geographical distribution of AHS in Namibia. Weekly collections of Culicoides were made during the AHS peak season from January to May for 2013 and 2014 using the Onderstepoort 220V UV-light trap. Out of 397 collections made, 124 collections (3287 Culicoides) were analysed for AHSV presence with RT-qPCR. A total of 295 collections were analysed for total Culicoides (all collected Culicoides individuals) and in 75% of these collections the Culicoides were identified to species level. C. imicola was the dominant species with proportional representation of 29.9%. C. subschultzei, C. exspectator and C. ravus each contribute more than 10% to the species composition. The lowest number of Culicoides was collected at Aus 9980, a total of 21819 at Windhoek and the highest number at Okahandja 47343. AHSV was present at all three sites during 2013 but only in Windhoek and Okahandja during 2014. Multivariate analyses of data from the two year survey indicate the environmental parameters in order of importance for the distribution of AHS in Namibia as precipitation>temperature>clay>relative humidity>NDVI. The implication of these findings is that any precipitation event increases Culicoides numbers significantly. Together with these results the high number of species found of which little is known regarding their vector competence, add to the complexity of the distribution of AHS in Namibia. PMID:27491343

  3. Phytotoxic Activity and Chemical Composition of Aqueous Volatile Fractions from Eucalyptus Species

    PubMed Central

    Zhang, Jinbiao; An, Min; Wu, Hanwen; Liu, De Li; Stanton, Rex

    2014-01-01

    The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii) have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.). The aqueous volatile fractions (AVFs) were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions) during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph–mass spectrometry (GC-MS). Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species. PMID:24681490

  4. Phytotoxic activity and chemical composition of aqueous volatile fractions from Eucalyptus species.

    PubMed

    Zhang, Jinbiao; An, Min; Wu, Hanwen; Liu, De Li; Stanton, Rex

    2014-01-01

    The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii) have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.). The aqueous volatile fractions (AVFs) were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions) during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph-mass spectrometry (GC-MS). Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species. PMID:24681490

  5. [Species and size composition of fishes in Barra de Navidad lagoon, Mexican central Pacific].

    PubMed

    González-Sansón, Gaspar; Aguilar-Betancourt, Consuelo; Kosonoy-Aceves, Daniel; Lucano-Ramírez, Gabriela; Ruiz-Ramírez, Salvador; Flores-Ortega, Juan Ramón; Hinojosa-Larios, Angel; de Asís Silva-Bátiz, Francisco

    2014-03-01

    Coastal lagoons are considered important nursery areas for many coastal fishes. Barra de Navidad coastal lagoon (3.76km2) is important for local economy as it supports tourism development and artisanal fisheries. However, the role of this lagoon in the dynamics of coastal fish populations is scarcely known. Thus, the objectives of this research were: to characterize the water of the lagoon and related weather conditions, to develop a systematic list of the ichthyofauna, and to estimate the proportion of juveniles in the total number of individuals captured of most abundant species. Water and fish samples were collected between March 2011 and February 2012. Physical and chemical variables were measured in rainy and dry seasons. Several fishing gears were used including a cast net, beach purse seine and gillnets of four different mesh sizes. Our results showed that the lagoon is most of the time euhaline (salinity 30-40ups), although it can be mixopolyhaline (salinity 18-30ups) during short periods. Chlorophyll and nutrients concentrations suggested eutrophication in the lagoon. Mean water temperature changed seasonally from 24.9 degrees C (April, high tide) to 31.4 degrees C (October, low tide). Considering ichthyofauna species, a total of 36 448 individuals of 92 species were collected, 31 of them adding up to 95% of the total of individuals caught. Dominant species were Anchoa spp. (44.6%), Diapterus peruvianus (10.5%), Eucinostomus currani (8.1%), Cetengraulis mysticetus (7.8%), Mugil curema (5.2%) and Opisthonema libertate (4.5%). The lagoon is an important juvenile habitat for 22 of the 31 most abundant species. These included several species of commercial importance such as snappers (Lutjanus argentiventris, L. colorado and L. novemfasciatus), snook (Centropomus nigrescens) and white mullet (Mugil curema). Other four species seem to use the lagoon mainly as adults. This paper is the first contribution on the composition of estuarine ichthyofauna in Jalisco

  6. Seasonal Phenology and Species Composition of the Aphid Fauna in a Northern Crop Production Area

    PubMed Central

    Kirchner, Sascha M.; Hiltunen, Lea; Döring, Thomas F.; Virtanen, Elina; Palohuhta, Jukka P.; Valkonen, Jari P. T.

    2013-01-01

    Background The species diversity of aphids and seasonal timing of their flight activity can have significant impacts on crop production, as aphid species differ in their ability to transmit plant viruses and flight timing affects virus epidemiology. The aim of the study was to characterise the species composition and phenology of aphid fauna in Finland in one of the northernmost intensive crop production areas of the world (latitude 64°). Methodology/Principal Findings Flight activity was monitored in four growing seasons (2007–010) using yellow pan traps (YPTs) placed in 4–8 seed potato fields and a Rothamsted suction trap. A total of 58,528 winged aphids were obtained, identified to 83 taxa based on morphology, and 34 species were additionally characterised by DNA barcoding. Seasonal flight activity patterns analysed based on YPT catch fell into three main phenology clusters. Monoecious taxa showed early or middle-season flight activity and belonged to species living on shrubs/trees or herbaceous plants, respectively. Heteroecious taxa occurred over the entire potato growing season (ca. 90 days). Abundance of aphids followed a clear 3-year cycle based on suction trap data covering a decade. Rhopalosiphum padi occurring at the end of the potato growing season was the most abundant species. The flight activity of Aphis fabae, the main vector of Potato virus Y in the region, and Aphis gossypii peaked in the beginning of potato growing season. Conclusions/Significance Detailed information was obtained on phenology of a large number aphid species, of which many are agriculturally important pests acting as vectors of plant viruses. Aphis gossypii is known as a pest in greenhouses, but our study shows that it occurs also in the field, even far in the north. The novel information on aphid phenology and ecology has wide implications for prospective pest management, particularly in light of climate change. PMID:23967149

  7. Abundance, species composition of microzooplankton from the coastal waters of Port Blair, South Andaman Island

    PubMed Central

    2012-01-01

    Background Microzooplankton consisting of protists and metazoa <200 μm. It displays unique feeding mechanisms and behaviours that allow them to graze cells up to five times their own volume. They can grow at rates which equal or exceed prey growth and can serve as a viable food source for metazoans. Moreover, they are individually inconspicuous, their recognition as significant consumers of oceanic primary production. The microzooplankton can be the dominant consumers of phytoplankton production in both oligo- and eutrophic regions of the ocean and are capable of consuming >100% of primary production. Results The microzooplankton of the South Andaman Sea were investigated during September 2011 to January 2012. A total of 44 species belong to 19 genera were recorded in this study. Tintinnids made larger contribution to the total abundance (34%) followed in order by dinoflagellates (24%), ciliates (20%) and copepod nauplii (18%). Foraminifera were numerically less (4%). Tintinnids were represented by 20 species belong to 13 genera, Heterotrophic dinoflagellates were represented by 17 species belong to 3 genera and Ciliates comprised 5 species belong to 3 genera. Eutintinus tineus, Tintinnopsis cylindrical, T. incertum, Protoperidinium divergens, Lomaniella oviformes, Strombidium minimum were the most prevalent microzooplankton. Standing stock of tintinnids ranged from 30–80 cells.L-1 and showed a reverse distribution with the distribution of chlorophyll a relatively higher species diversity and equitability was found in polluted harbour areas. Conclusions The change of environmental variability affects the species composition and abundance of microzooplankton varied spatially and temporarily. The observations clearly demonstrated that the harbor area differed considerably from other area in terms of species present and phytoplankton biomass. Further, the phytoplankton abundance is showed to be strongly influenced by tintinnid with respect to the relationship of

  8. Plant compartment and biogeography affect microbiome composition in cultivated and native Agave species.

    PubMed

    Coleman-Derr, Devin; Desgarennes, Damaris; Fonseca-Garcia, Citlali; Gross, Stephen; Clingenpeel, Scott; Woyke, Tanja; North, Gretchen; Visel, Axel; Partida-Martinez, Laila P; Tringe, Susannah G

    2016-01-01

    Desert plants are hypothesized to survive the environmental stress inherent to these regions in part thanks to symbioses with microorganisms, and yet these microbial species, the communities they form, and the forces that influence them are poorly understood. Here we report the first comprehensive investigation of the microbial communities associated with species of Agave, which are native to semiarid and arid regions of Central and North America and are emerging as biofuel feedstocks. We examined prokaryotic and fungal communities in the rhizosphere, phyllosphere, leaf and root endosphere, as well as proximal and distal soil samples from cultivated and native agaves, through Illumina amplicon sequencing. Phylogenetic profiling revealed that the composition of prokaryotic communities was primarily determined by the plant compartment, whereas the composition of fungal communities was mainly influenced by the biogeography of the host species. Cultivated A. tequilana exhibited lower levels of prokaryotic diversity compared with native agaves, although no differences in microbial diversity were found in the endosphere. Agaves shared core prokaryotic and fungal taxa known to promote plant growth and confer tolerance to abiotic stress, which suggests common principles underpinning Agave-microbe interactions. PMID:26467257

  9. Annual cycle of zooplankton abundance and species composition in Izmit Bay (the northeastern Marmara Sea)

    NASA Astrophysics Data System (ADS)

    Isinibilir, Melek; Kideys, Ahmet E.; Tarkan, Ahmet N.; Yilmaz, I. Noyan

    2008-07-01

    The monthly abundance, biomass and taxonomic composition of zooplankton of Izmit Bay (the northeastern Marmara Sea) were studied from October 2001 to September 2002. Most species within the zooplankton community displayed a clear pattern of succession throughout the year. Generally copepods and cladocerans were the most abundant groups, while the contribution of meroplankton increased at inner-most stations and dominated the zooplankton. Both species number ( S) and diversity ( H') were positively influenced by the increase in salinity of upper layers ( r = 0.30 and r = 0.31, p < 0.001, respectively), while chlorophyll a was negatively affected ( r = -0.36, p < 0.001). Even though Noctiluca scintillans had a significant seasonality ( F11,120 = 8.45, p < 0.001, ANOVA), abundance was not related to fluctuations in temperature and only chlorophyll a was adversely correlated ( r = -0.35, p < 0.001). In general, there are some minor differences in zooplankton assemblages of upper and lower layers. A comparison of the species composition and abundance of Izmit Bay with other Black Sea bays reveals a high similarity between them.

  10. Effects of habitat composition and landscape structure on worker foraging distances of five bumble bee species.

    PubMed

    Redhead, John W; Dreier, Stephanie; Bourke, Andrew F G; Heard, Matthew S; Jordan, William C; Sumner, Seirian; Wang, Jinliang; Carvell, Claire

    2016-04-01

    Bumble bees (Bombus spp.) are important pollinators of both crops and wildflowers. Their contribution to this essential ecosystem service has been threatened over recent decades by changes in land use, which have led to declines in their populations. In order to design effective conservation measures, it is important to understand the effects of variation in landscape composition and structure on the foraging activities of worker bumble bees. This is because the viability of individual colonies is likely to be affected by the trade-off between the energetic costs of foraging over greater distances and the potential gains from access to additional resources. We used field surveys, molecular genetics, and fine resolution remote sensing to estimate the locations of wild bumble bee nests and to infer foraging distances across a 20-km² agricultural landscape in southern England, UK. We investigated five species, including the rare B. ruderatus and ecologically similar but widespread B. hortorum. We compared worker foraging distances between species and examined how variation in landscape composition and structure affected foraging distances at the colony level. Mean worker foraging distances differed significantly between species. Bombus terrestris, B. lapidarius, and B. ruderatus exhibited significantly greater mean foraging distances (551, 536, and 501 m, respectively) than B. hortorum and B. pascuorum (336 and 272 m, respectively). There was wide variation in worker foraging distances between colonies of the same species, which was in turn strongly influenced by the amount and spatial configuration of available foraging habitats. Shorter foraging distances were found for colonies where the local landscape had high coverage and low fragmentation of semi-natural vegetation, including managed agri-environmental field margins. The strength of relationships between different landscape variables and foraging distance varied between species, for example the strongest

  11. [Dietary composition and food competition of six main fish species in rocky reef habitat off Gouqi Island].

    PubMed

    Wang, Kai; Zhang, Shou-Yu; Wang, Zhen-Hua; Zhao, Jing; Xu, Min; Lin, Jun

    2012-02-01

    Based on the monthly investigation data of fish resources in the rocky reef habitat off Gouqi Island from March 2009 to February 2010, this paper studied the dietary composition of three native fish species (Sebasticus marmoratus, Hexagrammos otakii and Hexagrammos agrammus) and three non-native fish species (Lateolabrax japonica, Nibea albiflora and Larimichthys polyactis). The analysis of gut content indicated that the main prey items of these six dominant fish species were Caprellidae, Gammaridea, juvenile S. marmoratus, Engraulis japonicas and Acetes chinensis and the dietary composition of each of the 6 fish species had obvious seasonal variation. There was an intense food competition between native species H. otakii and H. agrammus in autumn, between non-native species N. albiflora and L. polyactis in summer, between non-native species N. albiflora and native species S. marmoratus in autumn, and between non-native species N. albiflora and native species H. otakii in winter. It was suggested the non-native species N. albiflora was the key species in the food competition among the six dominant fish species in this rocky reef habitat, and thus the feeding behaviors of these six fish species could have definite effects on the resource capacity of juvenile S. marmoratus. PMID:22586984

  12. Non-conventional approaches to food processing in CELSS, 1. Algal proteins: Characterization and process optimization

    NASA Technical Reports Server (NTRS)

    Nakhost, Z.; Karel, M.; Krukonis, V. J.

    1987-01-01

    Protein isolate obtained from green algae cultivated under controlled conditions was characterized. Molecular weight determination of fractionated algal proteins using SDS-polyacrylamide gel electrophoresis revealed a wide spectrum of molecular weights ranging from 15,000 to 220,000. Isoelectric points of dissociated proteins were in the range of 3.95 to 6.20. Amino acid composition of protein isolate compared favorably with FAO standards. High content of essential amino acids leucine, valine, phenylalanine and lysine make algal protein isolate a high quality component of closed ecological life support system diets. To optimize the removal of algal lipids and pigments supercritical carbon dioxide extraction (with and without ethanol as a co-solvent) was used. Addition of ethanol to supercritical carbon dioxide resulted in more efficient removal of algal lipids and produced protein isolate with a good yield and protein recovery. The protein isolate extracted by the above mixture had an improved water solubility.

  13. Non-conventional approaches to food processing in CELSS. I - Algal proteins: Characterization and process optimization

    NASA Technical Reports Server (NTRS)

    Nakhost, Z.; Karel, M.; Krukonis, V. J.

    1987-01-01

    Protein isolate obtained from green algae (Scenedesmus obliquus) cultivated under controlled conditions was characterized. Molecular weight determination of fractionated algal proteins using SDS-polyacrylamide gel electrophoresis revealed a wide spectrum of molecular weights ranging from 15,000 to 220,000. Isoelectric points of dissociated proteins were in the range of 3.95 to 6.20. Amino acid composition of protein isolate compared favorably with FAO standards. High content of essential amino acids leucine, valine, phenylalanine and lysine makes algal protein isolate a high quality component of CELSS diets. To optimize the removal of algal lipids and pigments supercritical carbon dioxide extraction (with and without ethanol as a co-solvent) was used. Addition of ethanol to supercritical CO2 resulted in more efficient removal of algal lipids and produced protein isolate with a good yield and protein recovery. The protein isolate extracted by the above mixture had an improved water solubility.

  14. From benchtop to raceway : spectroscopic signatures of dynamic biological processes in algal communities.

    SciTech Connect

    Trahan, Christine Alexandra; Garcia, Omar Fidel; Martino, Anthony A.; Raymer, Michelle; Collins, Aaron M.; Hanson, David T.; Turner, Tom; Powell, Amy Jo; James, Scott Carlton; Timlin, Jerilyn Ann; Scholle, Steven; Dwyer, Brian P.; Ruffing, Anne; Jones, Howland D. T.; Ricken, James Bryce; Reichardt, Thomas A.

    2010-08-01

    The search is on for new renewable energy and algal-derived biofuel is a critical piece in the multi-faceted renewable energy puzzle. It has 30x more oil than any terrestrial oilseed crop, ideal composition for biodiesel, no competition with food crops, can be grown in waste water, and is cleaner than petroleum based fuels. This project discusses these three goals: (1) Conduct fundamental research into the effects that dynamic biotic and abiotic stressors have on algal growth and lipid production - Genomics/Transcriptomics, Bioanalytical spectroscopy/Chemical imaging; (2) Discover spectral signatures for algal health at the benchtop and greenhouse scale - Remote sensing, Bioanalytical spectroscopy; and (3) Develop computational model for algal growth and productivity at the raceway scale - Computational modeling.

  15. Effects of ‘Target’ Plant Species Body Size on Neighbourhood Species Richness and Composition in Old-Field Vegetation

    PubMed Central

    Schamp, Brandon S.; Aarssen, Lonnie W.; Wight, Stephanie

    2013-01-01

    Competition is generally regarded as an important force in organizing the structure of vegetation, and evidence from several experimental studies of species mixtures suggests that larger mature plant size elicits a competitive advantage. However, these findings are at odds with the fact that large and small plant species generally coexist, and relatively smaller species are more common in virtually all plant communities. Here, we use replicates of ten relatively large old-field plant species to explore the competitive impact of target individual size on their surrounding neighbourhoods compared to nearby neighbourhoods of the same size that are not centred by a large target individual. While target individuals of the largest of our test species, Centaurea jacea L., had a strong impact on neighbouring species, in general, target species size was a weak predictor of the number of other resident species growing within its immediate neighbourhood, as well as the number of resident species that were reproductive. Thus, the presence of a large competitor did not restrict the ability of neighbouring species to reproduce. Lastly, target species size did not have any impact on the species size structure of neighbouring species; i.e. they did not restrict smaller, supposedly poorer competitors, from growing and reproducing close by. Taken together, these results provide no support for a size-advantage in competition restricting local species richness or the ability of small species to coexist and successfully reproduce in the immediate neighbourhood of a large species. PMID:24349177

  16. Cyanobacterial-algal cenoses in ordinary chernozems under the impact of different phytoameliorants

    NASA Astrophysics Data System (ADS)

    Dubovik, I. E.; Suyundukov, Ya. T.; Khasanova, R. F.; Shalygina, R. R.

    2016-04-01

    General ecological and taxonomic characteristics of cyanobacterial-algal cenoses in ordinary chernozems under different ameliorative plants (phytoameliorants) were studied in the Trans-Ural region of the Republic of Bashkortostan. A comparative analysis of the taxa of studied cenoses in the soils under leguminous herbs and grasses was performed. The phytoameliorative effect of different herbs and their relationships with cyanobacterial-algal cenoses were examined. Overall, 134 cyanoprokaryotic and algal species belonging to 70 genera, 36 families, 15 orders, and 9 classes were identified. Cyanobacterial-algal cenoses included the divisions of Chlorophyta, Cyanoprokaryota, Xanthophyta, Bacillariophyta, and Euglenophyta. Representatives of Ch-, X-, CF-, and P-forms were the leading ecobiomorphs in the studied cenoses.

  17. Effect of Algal Inoculation on COD and Nitrogen Removal, and Indigenous Bacterial Dynamics in Municipal Wastewater.

    PubMed

    Lee, Jangho; Lee, Jaejin; Shukla, Sudheer Kumar; Park, Joonhong; Lee, Tae Kwon

    2016-05-28

    The effects of algal inoculation on chemical oxygen demand (COD) and total nitrogen (TN) removal, and indigenous bacterial dynamics were investigated in municipal wastewater. Experiments were conducted with municipal wastewater inoculated with either Chlorella vulgaris AG10032, Selenastrum gracile UTEX 325, or Scenedesmus quadricauda AG 10308. C. vulgaris and S. gracile as fast growing algae in municipal wastewater, performed high COD and TN removal in contrast to Sc. quadricauda. The indigenous bacterial dynamics revealed by 16S rRNA gene amplification showed different bacterial shifts in response to different algal inoculations. The dominant bacterial genera of either algal case were characterized as heterotrophic nitrifying bacteria. Our results suggest that selection of indigenous bacteria that symbiotically interact with algal species is important for better performance of wastewater treatment. PMID:26930350

  18. Chemical composition and variability of the volatile components from inflorescences of Cirsium species.

    PubMed

    Kozyra, Małgorzata; Mardarowicz, Marek; Kochmańska, Joanna

    2015-01-01

    The present study aimed to investigate the chemical composition of the essential oils of inflorescences Cirsium spp. (Asteraceae) by GC/MS method. Essential oils were extracted from the inflorescences of Cirsium pannonicum (Link), Cirsium ligulare Boiss., Cirsium heterophyllum (L.) Hill., Cirsium acaule (L.) Scop., Cirsium oleraceum (L.) Scop., Cirsium dissectum (L.) Hill., Cirsium decussatum (Janka) and Cirsium eriophorum (L.) Scop., using the steam distillation method. A gas chromatography-mass spectrometry method was employed for the analysis of essential oils. Our study shows the differences in chemical composition of volatile oils in the inflorescences of Cirsium spp. The main components of the essential oil were ketones and aldehydes with a long carbon side-chain. Volatile oils also contained small amounts of terpenes: thymol, β-linalool, eugenol, carvacrol and fatty acids with odd number of carbon atoms-waxes. The compounds in the essential oils obtained from inflorescences Cirsium L. species have been identified for the first time. PMID:25674834

  19. ISOB: A Database of Indigenous Snake Species of Bangladesh with respective known venom composition

    PubMed Central

    Roly, Zahida Yesmin; Hakim, Md Abdul; Zahan, ASM Shahriar; Hossain, M Monzur; Reza, Md Abu

    2015-01-01

    At present there is no well structured database available for the venomous snakes and venom composition of snakes in the world although venom has immense importance in biomedical research. Searching for a specific venom component from NCBI, PDB or public databases is troublesome, because they contain huge amount of data entries. Therefore, we created a database named “ISOB” which is a web accessible unique secondary database that represents the first online available bioinformatics resource showing venom composition of snakes. This database provides a comprehensive overview of seventy-eight indigenous snake species covering description of snakes supplemented with structural information of the relevant individual available venom proteins. We strongly believe that this database will contribute significantly in the field of bioinformatics, environmental research, proteomics, drug development and rationale drug designing. Availability The database is freely available at http://www.snakebd.com/ PMID:25848172

  20. Process for derivatizing carbon nanotubes with diazonium species and compositions thereof

    NASA Technical Reports Server (NTRS)

    Tour, James M. (Inventor); Bahr, Jeffrey L. (Inventor); Yang, Jiping (Inventor)

    2011-01-01

    Methods for the chemical modification of carbon nanotubes involve the derivatization of multi- and single-wall carbon nanotubes, including small diameter (ca. 0.7 nm) single-wall carbon nanotubes, with diazonium species. The method allows the chemical attachment of a variety of organic compounds to the side and ends of carbon nanotubes. These chemically modified nanotubes have applications in polymer composite materials, molecular electronic applications, and sensor devices. The methods of derivatization include electrochemical induced reactions, thermally induced reactions, and photochemically induced reactions. Moreover, when modified with suitable chemical groups, the derivatized nanotubes are chemically compatible with a polymer matrix, allowing transfer of the properties of the nanotubes (such as, mechanical strength or electrical conductivity) to the properties of the composite material as a whole. Furthermore, when modified with suitable chemical groups, the groups can be polymerized to form a polymer that includes carbon nanotubes.

  1. Leptospirosis risk increases with changes in species composition of rat populations

    NASA Astrophysics Data System (ADS)

    Theuerkauf, Jörn; Perez, Julie; Taugamoa, Alefosio; Niutoua, Iasinito; Labrousse, Didier; Gula, Roman; Bogdanowicz, Wieslaw; Jourdan, Hervé; Goarant, Cyrille

    2013-04-01

    Rats are major reservoirs of leptospirosis and considered as a main threat to biodiversity. A recent introduction of Rattus rattus to the island of Futuna (Western Polynesia) provided the opportunity to test if a possible change in species composition of rat populations would increase the risk of leptospirosis to humans. We trapped rodents on Wallis and Futuna and assessed Leptospira carriage in 357 rodents ( Rattus norvegicus, R. rattus, Rattus exulans, and Mus domesticus) from 2008 to 2012. While Leptospira prevalence in rodents and the composition of rat populations on Futuna fluctuated with rainfall, the biomass of Leptospira-carrying rodents has been continuously rising from 2008 to 2012. Our results suggest that the introduction of R. rattus increases the risk to humans being infected with leptospirosis by rats.

  2. Spatial distribution and species composition of small pelagic fishes in the Gulf of California.

    PubMed

    Lanz, Edgar; Nevárez-Martínez, Manuel O; López-Martínez, Juana; Dworak, Juan A

    2008-06-01

    Traditional regionalization methods in fisheries based on provinces or major fishing areas, includes large and arbitrary grids in which basic statistics or inferences on distribution or abundance are made. We describe a method for regionalization and analysis of fishing activities for small pelagic fisheries in the Gulf of California based on spatial patterns of landing and catch data in a Geographic Information System (GIS) environment. A fisheries database from logbooks with spatial attributes from October 2002 to June 2007 was analyzed. Landings and catching data were transformed to a Weighted Region Index (WRI) by using fuzzy logic operators. The WRI revealed fishing action centers characterized by areas with the highest WRI values, and a hierarchy for the relative importance of the regions was established. Guaymas, Desemboque de Caborca, Isla Patos, and Bahia San Rafael they were the most prominent ones. An analysis of the relative frequency of species composition showed that the Pacific sardine had an over 80 % abundance in the midriff islands, and remained as the most important in the upper gulf regions, while in the central part of the gulf, relative abundances of Pacific sardine and Northern anchovy were more balanced. Relative abundance of mackerel was significantly larger around Isla Patos than in any other place. Guaymas had the largest relative composition of Northern anchovy and the lowest values for Pacific sardine. Desemboque de Caborca showed the largest homogeneity in species relative composition. It is important to highlight that this results come from in situ data, while the results previously reported come from landing statistics by port. Therefore, the present method acknowledges the spatial differences of species by regions, additional to the traditional time series analysis. PMID:19256429

  3. Semi-volatile inorganic species: importance for atmospheric chemical composition on diurnal and seasonal timescales

    NASA Astrophysics Data System (ADS)

    Pearce, Hana; Mann, Graham; Arnold, Stephen; O'Connor, Fiona; Benduhn, Francois; Rumbold, Steven; Pringle, Kirsty

    2016-04-01

    Nitrate aerosol has become an important driver of reduced European air quality and climate forcing, following reductions in sulphate precursor emissions since the 1980s, and is expected to be more influential in future decades. Measurements from the European Integrated Project on Aerosol and Cloud Climate Air Quality Interactions (EUCAARI) field campaign have shown that semi-volatile aerosol species such as ammonium nitrate can comprise a major component of the sub-micron particulate matter, particularly in high pollution episodes. This presentation will assess the contribution of semi-volatile inorganic aerosol to diurnal and seasonal cycles in atmospheric chemical composition over Europe. We use the UM-UKCA composition-climate model, including the GLOMAP interactive aerosol microphysics module and a recently developed 'hybrid' dissolution solver (HyDis) to accurately represent size-resolved partitioning of ammonia and nitric acid to the particle phase. In particular, we evaluate simulated size-resolved composition variations over Europe through the diurnal cycle, comparing hourly model output to Aerosol Mass Spectrometer observations at several sites during 2008. We will present the results of this composition analysis, in addition to model evaluation from comparisons with European Monitoring for Environmental Protection (EMEP) network and EUCAARI field campaign observations.

  4. Chemical compositions and larvicidal activities of leaf essential oils from two eucalyptus species.

    PubMed

    Cheng, Sen-Sung; Huang, Chin-Gi; Chen, Ying-Ju; Yu, Jane-Jane; Chen, Wei-June; Chang, Shang-Tzen

    2009-01-01

    In the current study, the mosquito larvicidal activity of leaf essential oils and their constituents from two eucalyptus species (Eucalyptus camaldulensis and Eucalyptus urophylla) against two mosquito species, Aedes aegypti and Aedes albopictus, was investigated. In addition, the chemical compositions of the leaf essential oils were analyzed using gas chromatography-mass spectrometry. Results from the larvicidal tests revealed that essential oil from the leaves of E. camaldulensis had an excellent inhibitory effect against both A. aegypti and A. albopictus larvae. The 12 pure constituents extracted from the two eucalyptus leaf essential oils were also tested individually against two mosquito larvae. Among the six effective constituents, alpha-terpinene exhibits the best larvicidal effect against both A. aegypti and A. albopictus larvae. Results of this study show that the leaf essential oil of E. camaldulensis and its effective constituents might be considered as a potent source for the production of fine natural larvicides. PMID:18396398

  5. The biological activities and chemical composition of Pereskia species (Cactaceae)--a review.

    PubMed

    Pinto, Nícolas de Castro Campos; Scio, Elita

    2014-09-01

    The exploration of nature as a source of sustainable, novel bioactive substances continues to grow as natural products play a significant role in the search for new therapeutic and agricultural agents. In this context, plants of the genus Pereskia (Cactaceae) have been studied for their biological activities, and are evolving as an interesting subject in the search for new, bioactive compounds. These species are commonly used as human foodstuffs and in traditional medicine to treat a variety of diseases. This review focuses on the bioactivity and chemical composition of the genus Pereskia, and aims to stimulate further studies on the chemistry and biological potential of the genus. PMID:24862084

  6. Different Assembly Processes Drive Shifts in Species and Functional Composition in Experimental Grasslands Varying in Sown Diversity and Community History

    PubMed Central

    Roscher, Christiane; Schumacher, Jens; Gerighausen, Uta; Schmid, Bernhard

    2014-01-01

    Background The prevalence of different biotic processes (limiting similarity, weaker competitor exclusion) and historical contingency due to priority effects are in the focus of ongoing discussions about community assembly and non-random functional trait distributions. Methodology/Principal Findings We experimentally manipulated assembly history in a grassland biodiversity experiment (Jena Experiment) by applying two factorially crossed split-plot treatments to all communities: (i) duration of weeding (never weeded since sowing or cessation of weeding after 3 or 6 years); (ii) seed addition (control vs. seed addition 4 years after sowing). Spontaneous colonization of new species in the control treatment without seed addition increased realized species richness and functional richness (FRic), indicating continuously denser packing of niches. Seed addition resulted in forced colonization and increased realized species richness, FRic, functional evenness (FEve) and functional divergence (FDiv), i.e. higher abundances of species with extreme trait values. Furthermore, the colonization of new species led to a decline in FEve through time, suggesting that weaker competitors were reduced in abundance or excluded. Communities with higher initial species richness or with longer time since cessation of weeding were more restricted in the entry of new species and showed smaller increases in FRic after seed addition than other communities. The two assembly-history treatments caused a divergence of species compositions within communities originally established with the same species. Communities originally established with different species converged in species richness and functional trait composition over time, but remained more distinct in species composition. Conclusions/Significance Contrasting biotic processes (limiting similarity, weaker competitor exclusion) increase functional convergence between communities initially established with different species. Historical

  7. Species composition and diversity of macrobenthos in the intertidal zone of Xiangshan bay, China

    NASA Astrophysics Data System (ADS)

    Jiao, Haifeng; Zheng, Dan; You, Zhongjie; Xu, Nianjun; Lou, Dan; Huang, Chengwei

    2015-04-01

    Xiangshan bay is a narrow semi-closed bay and situated on the northwestern coast of the East China Sea. Over past decades, it has become to a major bay with intensive human activities, dense urbanized area, and poor water quality. The aim of this paper was to reveal the ecological status through the elucidation of the species composition, abundance, biomass and diversity of macrobenthos in this bay. Six intertidal sections were surveyed from January 2007 to November 2008 quarterly. Sections TG, HD and XH are located in the three inner bays, sections QJ and WS are located near the thermal power plants, and section XX is located at the outer part of Xiangshan Bay. Great variations in macrobenthos community were indentified, and the species composition of the community in the present study showed the dominance in the order of molluscs (bivalves and gastropods), crustaceans and others, and only few Polychaeta were recorded. Only three dominant species, Littorina brevicula, Ilyplax tansuiensis, and Cerithidea cingulata were collected in all the sections, and a total of 19 dominant species were recorded only in one section. Two-way ANOVA analyses of abundance indicated that there were significant differences among sections or seasons. Shannon-Wiener diversity index ( H') had its maximum (2.45) in section QJ, and minimum (1.76) in section TG. Multiple irregular k-dominance plots clearly showed that the study area was polluted and the macrobenthos community was under stress. We conclude that the macrobenthos of Xiangshan Bay have been disturbed by human activities, especially at the interior bay.

  8. The Influence of Habitat Structure on Bird Species Composition in Lowland Malaysian Rain Forests

    PubMed Central

    Mansor, Mohammad Saiful; Sah, Shahrul Anuar Mohd

    2012-01-01

    Bird surveys were conducted in the Bukit Kepala Gajah limestone area in Lenggong, Perak from July 2010 to January 2011. The study area was divided into three zones: forest edge, forest intermediate and forest interior. A point-count distance sampling method was used in the bird surveys. The study recorded 7789 detections, representing 100 bird species belonging to 28 families. Pycnonotidae, Timaliidae and Nectariniidae were the dominant families overall and showed the highest number of observations recorded in the study area whereas Motacillidae showed the fewest observations. The bird species were grouped into three feeding guilds: insectivores, frugivores and others (omnivores, carnivores, nectarivores and granivores). The species richness of insectivorous birds differed significantly among the forest zones sampled (Kruskal-Wallis: α=0.05, H=10.979, d.f.=2, p=0.004), with more insectivorous birds occurring in the forest interior. No significant differences were found among the zones in the species richness of either the frugivore guild or the composite others guild. PMID:24575221

  9. Anthropophilic Anopheles species composition and malaria in Tierradentro, Córdoba, Colombia

    PubMed Central

    Schiemann, David Joachim; Pinzón, Martha Lucía Quiñones; Hankeln, Thomas

    2014-01-01

    Malaria is still a primary health problem in Colombia. The locality of Tierradentro is situated in the municipality of Montelíbano, Córdoba, in the northwest of Colombia, and has one of the highest annual parasite index of malaria nationwide. However, the vectors involved in malaria transmission in this locality have not yet been identified. In this study, the local anthropophilic Anopheles composition and natural infectivity with Plasmodium were investigated. In August 2009, 927 female Anopheles mosquitoes were collected in eight localities using the human landing catch method and identified based on their morphology. Cryptic species were determined by restriction fragment length polymorphism-internal transcribed spacer (ITS)2 molecular analysis. Eight species [Anopheles nuneztovari s.l. (92.8%), Anopheles darlingi (5.1%), Anopheles triannulatus s.l. (1.8%), Anopheles pseudopunctipennis s.l. (0.2%), Anopheles punctimacula s.l. (0.2%), Anopheles apicimacula (0.1%), Anopheles albimanus (0.1%) and Anopheles rangeli (0.1%)] were identified and species identity was confirmed by ITS2 sequencing. This is the first report of An. albimanus, An. rangeli and An. apicimacula in Tierradentro. Natural infectivity with Plasmodium was determined by ELISA. None of the mosquitoes was infectious for Plasmodium. An. nuneztovari s.l. was the predominant species and is considered the primary malaria vector; An. darlingi and An. triannulatus s.l. could serve as secondary vectors.

  10. Does host plant influence parasitism and parasitoid species composition in Lygus rugulipennis? A molecular approach.

    PubMed

    Gariepy, T D; Kuhlmann, U; Gillott, C; Erlandson, M

    2008-06-01

    Lygus Hahn plant bugs (Hemiptera: Miridae) are serious pests of a wide variety of economically important crops in North America. European Peristenus digoneutis Loan and P. relictus Ruthe (Hymenoptera: Braconidae) are being considered for release in Canada as part of a classical biological control program for Lygus. The attractiveness of different host plants to European Peristenus has not been addressed, but may be an important consideration prior to parasitoid release. Lygus rugulipennis Poppius nymphs were collected in the Northern Temperate Atlantic (NTA) ecoregion on red clover (Trifolium pratense L.; Fabaceae) and chamomile (Matricaria recutita L.; Asteraceae), and in the Western European Broadleaf Forest (WEBF) ecoregion on red clover and alfalfa (Medicago sativa L.; Fabaceae). Parasitism levels and parasitoid species were determined using a multiplex PCR assay for P. digoneutis, P. relictus, and P. pallipes Curtis. Mean parasitism levels in L. rugulipennis were 45-49% in the NTA ecoregion and 25-32% in the WEBF ecoregion. However, in neither ecoregion were parasitism levels and parasitoid species compositions significantly different in nymphs from different host plant species. Furthermore, multiparasitism was low despite the fact that P. digoneutis and P. relictus share the same host species. PMID:18439339

  11. [Distribution and species composition of hyporheic macroinvertebrates in a mountain stream].

    PubMed

    Zhang, Yue-wei; Yuan, Xing-zhong; Liu, Hong; Ren, Hai-qing; Deng, Wei; Wang, Xiao-feng

    2015-09-01

    Hyporheic macroinvertebrates are an important component of stream ecosystem. The composition and distribution of the hyporheic macroinvertebrates were investigated using artificial substrates in the upper reaches of Heishuitan River in August, December 2013 and April 2014. The results indicated that a total of 27 microinvertbrate species were identified in all three seasons. In summer, 22 species were identified, accounting for 81.8% of aquatic insects. 16 species were identified both in winter and spring, accounting for 75.0% and 62.5% of aquatic insects, respectively. The density of macroinvertebrate assemblage was significantly lower in summer than in winter and spring, and was the highest in spring. The biomass of macroinvertebrate assemblage was significantly higher in winter than in summer and spring, and was the lowest in summer. Species richness, Shannon index and Pielou index all had no significant difference among the three seasons. The density and richness of macroinvertebrates decreased with bed depth, and the maximum invertebrate density was found within the top 20 cm of the stream bed. Collector-filterer and collector-gatherer were the dominant functional feeding group in all three seasons. The community structure and temporal-spatial distribution of macroinvertebrates were determined by interactions and life history strategy of macroinvertebrates, and physical-chemical factors of hyporheic zone. PMID:26785569

  12. Anopheles species composition explains differences in Plasmodium transmission in La Guajira, northern Colombia

    PubMed Central

    Herrera-Varela, Manuela; Orjuela, Lorena I; Peñalver, Cilia; Conn, Jan E; Quiñones, Martha L

    2014-01-01

    Malaria in La Guajira, the most northern state of Colombia, shows two different epidemiological patterns. Malaria is endemic in the municipality of Dibulla whereas in Riohacha it is characterised by sporadic outbreaks. This study aimed to establish whether differences in transmission patterns could be attributed to different vector species. The most abundant adult female species were Anopheles aquasalis, exclusive to Riohacha, and Anopheles darlingi, restricted to Dibulla. Anopheles mosquitoes were identified using morphology and the molecular markers internal transcribed spacer 2 and cytochrome c oxidase I. All specimens (n = 1,393) were tested by ELISA to determine natural infection rates with Plasmodium falciparum and Plasmodium vivax. An. darlingi was positive for P. vivax 210, with an infection rate of 0.355% and an entomological inoculation rate of 15.87 infective bites/person/year. Anopheles albimanus larvae were the most common species in Riohacha, found in temporary swamps; in contrast, in Dibulla An. darlingi were detected mainly in permanent streams. Distinctive species composition and larval habitats in each municipality may explain the differences in Plasmodium transmission and suggest different local strategies should be used for vector control.

  13. Unraveling algal lipid metabolism: Recent advances in gene identification.

    PubMed

    Khozin-Goldberg, Inna; Cohen, Zvi

    2011-01-01

    Microalgae are now the focus of intensive research due to their potential as a renewable feedstock for biodiesel. This research requires a thorough understanding of the biochemistry and genetics of these organisms' lipid-biosynthesis pathways. Genes encoding lipid-biosynthesis enzymes can now be identified in the genomes of various eukaryotic microalgae. However, an examination of the predicted proteins at the biochemical and molecular levels is mandatory to verify their function. The essential molecular and genetic tools are now available for a comprehensive characterization of genes coding for enzymes of the lipid-biosynthesis pathways in some algal species. This review mainly summarizes the novel information emerging from recently obtained algal gene identification. PMID:20709142

  14. Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

    NASA Astrophysics Data System (ADS)

    Sundareshwar, P. V.; Upadhayay, S.; Abessa, M.; Honomichl, S.; Berdanier, B.; Spaulding, S. A.; Sandvik, C.; Trennepohl, A.

    2011-05-01

    In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers.

  15. A Taste of Algal Genomes from the Joint Genome Institute

    SciTech Connect

    Kuo, Alan; Grigoriev, Igor

    2012-06-17

    Algae play profound roles in aquatic food chains and the carbon cycle, can impose health and economic costs through toxic blooms, provide models for the study of symbiosis, photosynthesis, and eukaryotic evolution, and are candidate sources for bio-fuels; all of these research areas are part of the mission of DOE's Joint Genome Institute (JGI). To date JGI has sequenced, assembled, annotated, and released to the public the genomes of 18 species and strains of algae, sampling almost all of the major clades of photosynthetic eukaryotes. With more algal genomes currently undergoing analysis, JGI continues its commitment to driving forward basic and applied algal science. Among these ongoing projects are the pan-genome of the dominant coccolithophore Emiliania huxleyi, the interrelationships between the 4 genomes in the nucleomorph-containing Bigelowiella natans and Guillardia theta, and the search for symbiosis genes of lichens.

  16. A MARINE ALGAL BIOASSAY METHOD: RESULTS WITH PESTICIDES AND INDUSTRIAL WASTES

    EPA Science Inventory

    A simple marine algal bioassay method is described for short- and long-term studies on pesticides and industrial wastes. It can be used for rapid screening of a variety of substances with single-species and multiple-species tests and gives relative toxicities of the pollutants te...

  17. Algal biosensor array on a single electrode.

    PubMed

    Tatsuma, Tetsu; Yoshida, Yutaka; Shitanda, Isao; Notsu, Hideo

    2009-02-01

    An algal array was prepared on a single transparent electrode, and photosynthetic activity of each algal channel and its inhibition by a toxin were monitored with a single-channel potentiostat by successive light irradiation with a LED array. PMID:19173040

  18. TEXAS HARMFUL ALGAL BLOOM COORDINATION MX964014

    EPA Science Inventory

    Harmful algal blooms (HAB) are an expanding problem in coastal Texas. Nearly � of the known harmful algal blooms along the Texas coast have occurred in the past ten years and have led to significant resource and tourism losses. For example, there are at least two types of toxic...

  19. Assessment of fish abundance and species composition at selected sites in South Dakota: an overview

    USGS Publications Warehouse

    Harwood, Alison

    2010-01-01

    The U.S. Geological Survey (USGS) conducted surveys of streams throughout the State of South Dakota during 2008-09 as part of the U.S. Environmental Protection Agency?s (USEPA) National Rivers and Streams Assessment (NRSA) Program. During 2008-09, as part of the stream assessment, the USGS completed surveys of fish populations and species composition at 64 sites. Fish were inventoried at 60 of the 64 sites, but not at four of the sites because water was too low to sustain fish or specific conductivity was too high to electroshock effectively. Four of the sites were surveyed in 2000-04 during the USEPA's Environmental Monitoring and Assessment Program-West (EMAP-West) project. Two wadeable sites and two boatable sites were revisited for quality-assurance/quality-control requirements. During the study, both wadeable and boatable streams were sampled using electrofishing equipment and methods. Of the 64 sites, 62 were wadeable and 2 were boatable. Procedures for sampling wadeable streams differed slightly from procedures for boatable streams. Backpack electrofishing equipment was used for wadeable streams, whereas boat electrofishing equipment was used for boatable streams. Wadeable streams also were fished in an opposite direction than boatable streams. Several species of fish were collected during the NRSA. Species diversity ranged from 0-11 species in wadeable streams and from 6-26 species in boatable streams. Many common species were sampled during the study. The most frequently sampled fish was the sand shiner (Notropis stramineus), with 609 individuals sampled. In contrast, only one heritage species, the skipjack herring (Alosa chrysochloris), was identified during 2008-09. Common anomalies found in fish caught were parasitic lesions, "black spot disease," and tumors. When comparing the fish sampling results for the four sites visited in both 2000-04 and in 2008-09, more individuals and species were collected during 2008-09 than in 2000-04 at two sites, whereas

  20. Predator-Induced Fleeing Behaviors in Phytoplankton: A New Mechanism for Harmful Algal Bloom Formation?

    PubMed Central

    Harvey, Elizabeth L.; Menden-Deuer, Susanne

    2012-01-01

    In the plankton, heterotrophic microbes encounter and ingest phytoplankton prey, which effectively removes >50% of daily phytoplankton production in the ocean and influences global primary production and biochemical cycling rates. Factors such as size, shape, nutritional value, and presence of chemical deterrents are known to affect predation pressure. Effects of movement behaviors of either predator or prey on predation pressure, and particularly fleeing behaviors in phytoplankton are thus far unknown. Here, we quantified individual 3D movements, population distributions, and survival rates of the toxic phytoplankton species, Heterosigma akashiwo in response to a ciliate predator and predator-derived cues. We observed predator-induced defense behaviors previously unknown for phytoplankton. Modulation of individual phytoplankton movements during and after predator exposure resulted in an effective separation of predator and prey species. The strongest avoidance behaviors were observed when H. akashiwo co-occurred with an actively grazing predator. Predator-induced changes in phytoplankton movements resulted in a reduction in encounter rate and a 3-fold increase in net algal population growth rate. A spatially explicit population model predicted rapid phytoplankton bloom formation only when fleeing behaviors were incorporated. These model predictions reflected field observations of rapid H. akashiwo harmful algal bloom (HAB) formation in the coastal ocean. Our results document a novel behavior in phytoplankton that can significantly reduce predation pressure and suggests a new mechanism for HAB formation. Phytoplankton behaviors that minimize predatory losses, maximize resource acquisition, and alter community composition and distribution patterns could have major implications for our understanding and predictive capacity of marine primary production and biochemical cycling rates. PMID:23029518

  1. Influence of global change-related impacts on the mercury toxicity of freshwater algal communities.

    PubMed

    Val, Jonatan; Muñiz, Selene; Gomà, Joan; Navarro, Enrique

    2016-01-01

    The climatic-change related increase of temperatures, are expected to alter the distribution and survival of freshwater species, ecosystem functions, and also the effects of toxicants to aquatic biota. This study has thus assessed, as a first time, the modulating effect of climate-change drivers on the mercury (Hg) toxicity of freshwater algal photosynthesis. Natural benthic algal communities (periphyton) have been exposed to Hg under present and future temperature scenarios (rise of 5 °C). The modulating effect of other factors (also altered by global change), as the quality and amount of suspended and dissolved materials in the rivers, has been also assessed, exposing algae to Hg in natural river water or a synthetic medium. The EC50 values ranged from the 0.15-0.74 ppm for the most sensitive communities, to the 24-40 ppm for the most tolerant. The higher tolerance shown by communities exposed to higher Hg concentrations, as Jabarrella was in agreement with the Pollution Induced Community Tolerance concept. In other cases, the dominance of the invasive diatom Didymosphenia geminata explained the tolerance or sensitivity of the community to the Hg toxicity. Results shown that while increases in the suspended solids reduced Hg bioavailability, changes in the dissolved materials - such as organic carbon - may increase it and thus its toxic effects on biota. The impacts of the increase of temperatures on the toxicological behaviour of periphyton (combining both changes at species composition and physiological acclimation) would be certainly modulated by other effects at the land level (i.e., alterations in the amount and quality of dissolved and particulate substances arriving to the rivers). PMID:26024757

  2. Role of species composition in malaria transmission by the Anopheles funestus group (Diptera: Culicidae) in Ghana.

    PubMed

    Dadzie, Samuel K; Brenyah, Ruth; Appawu, Maxwell A

    2013-06-01

    Malaria remains a public health problem in Ghana, with Anopheles gambiae and Anopheles funestus as the predominant vectors. While much information exists on the species composition of An. gambiae, very little exists for An. funestus. This study was carried out to determine the species composition of An. funestus Giles populations from three ecological areas in Ghana and investigate their role in malaria transmission. Mosquitoes were collected using human landing and pyrethrum spray methods. A total of 10,254 Anopheles individuals were collected, out of which An. funestus constituted 53.6% (5,496). An. funestus sensu stricto (s.s.) and Anopheles lessoni were identified as the only members of the An. funestus group in all three ecological areas. All 62 sporozoite positive specimens that were identified as An. funestus s.s. were highly anthropophilic with a human blood index in the range of 80-96%, whereas more than 83% of the An. leesoni had fed on either bovine, goat, or sheep. Malaria transmission was higher in the Sahel savannah area than the rest of the ecological zones, with An. funestus s.s. being implicated as a vector of malaria in all ecological zones. Anopheles leesoni occurred in all the ecological areas but played no role in malaria transmission. The study established the importance of An. funestus s.s. in malaria transmission in Ghana. PMID:23701614

  3. Measurement of key compositional parameters in two species of energy grass by Fourier transform infrared spectroscopy.

    PubMed

    Allison, Gordon G; Morris, Catherine; Hodgson, Edward; Jones, Jenny; Kubacki, Michal; Barraclough, Tim; Yates, Nicola; Shield, Ian; Bridgwater, Anthony V; Donnison, Iain S

    2009-12-01

    Two energy grass species, switch grass, a North American tuft grass, and reed canary grass, a European native, are likely to be important sources of biomass in Western Europe for the production of biorenewable energy. Matching chemical composition to conversion efficiency is a primary goal for improvement programmes and for determining the quality of biomass feed-stocks prior to use and there is a need for methods which allow cost effective characterisation of chemical composition at high rates of sample through-put. In this paper we demonstrate that nitrogen content and alkali index, parameters greatly influencing thermal conversion efficiency, can be accurately predicted in dried samples of these species grown under a range of agronomic conditions by partial least square regression of Fourier transform infrared spectra (R(2) values for plots of predicted vs. measured values of 0.938 and 0.937, respectively). We also discuss the prediction of carbon and ash content in these samples and the application of infrared based predictive methods for the breeding improvement of energy grasses. PMID:19660936

  4. Fruit composition diversity in land races and modern pepino (Solanum muricatum) varieties and wild related species.

    PubMed

    Herraiz, Franscisco J; Raigón, María D; Vilanova, Santiago; García-Martínez, María D; Gramazio, Pietro; Plazas, Mariola; Rodríguez-Burruezo, Adrián; Prohens, Jaime

    2016-07-15

    Pepino (Solanum muricatum) fruits from 15 accessions of cultivated pepino as well as six accessions from wild relatives were evaluated for contents in dry matter, protein, β-carotene, chlorophylls and seven minerals. Several-fold differences among accessions were found for most traits. Average values obtained were similar to those of melon and cucumber, but the phenolic contents were much higher. Wild species had significantly higher average contents for all traits vs. the cultivated pepino accessions. And, the comparisons among the cultivated pepino varieties showed that the modern varieties were more uniform in composition, and they possessed significantly lower concentrations of protein, P, K, and Zn than local land races. Most of the significant correlations among composition traits were positive. Our studies show that regular consumption of pepino fruits could make a significant contribution to the recommended daily intake of P, K, Fe and Cu as well as to the average daily intake of phenolics. Furthermore, the higher values for most nutrients measured in the wild species and in the local land races indicate that new pepino varieties with improved fruit contents in nutrient and bioactive compounds can be developed. PMID:26948588

  5. Seasonal synchronicity of algal assemblages in three Midwestern agricultural streams having varying concentrations of atrazine, nutrients, and sediment.

    PubMed

    Andrus, J Malia; Winter, Diane; Scanlan, Michael; Sullivan, Sean; Bollman, Wease; Waggoner, J B; Hosmer, Alan J; Brain, Richard A

    2013-08-01

    Numerous studies characterizing the potential effects of atrazine on algal assemblages have been conducted using micro- or mesocosms; however, few evaluations focused on in situ lotic algal communities, potentially confounding risk assessment conclusions. This exploratory study, conducted at several sites in the midwestern United States where atrazine is commonly used, presents in situ observations of native algal communities relative to atrazine exposure and other parameters. Planktonic and periphytic algae from three streams in three Midwestern states, having historically differing atrazine levels, were sampled over a 16-week period in 2011 encompassing atrazine applications and the summer algal growth period at each site. Changes in abundance, diversity, and composition of algal communities were placed in the context of hydrological, climatic, and water quality parameters (including components sometimes present in agricultural runoff) also collected during the study. Diatoms dominated communities at each of the three sites and periphyton was much more abundant than phytoplankton. As expected, significant variations in algal community and environmental parameters were observed between sites. However, correspondence analysis plots revealed that patterns of temporal variation in algal communities at each site and in periphyton or phytoplankton were dominated by seasonal environmental gradients. Significant concordance in these seasonal patterns was detected among sites and between phytoplankton and periphyton communities (via procrustes Protest analysis), suggesting synchronicity of algal communities across a regional scale. While atrazine concentrations generally exhibited seasonal trends at the study watersheds; no effects on algal abundance, diversity or assemblage structure were observed as a result of atrazine pulses. This lack of response may be due to exposure events of insufficient concentration or duration (consistent with previously reported results) or

  6. Retention of Anionic Species on Granite: Influence of Granite Composition - 12129

    SciTech Connect

    Videnska, Katerina; Havlova, Vaclava

    2012-07-01

    Technetium (Tc-99, T{sub 1/2} = 2.1.10{sup 5} yrs) and selenium (Se-79, T{sub 1/2} = 6.5.10{sup 4} yrs) belong among fission products, being produced by fission of nuclear fuel. Both elements can significantly contribute to risk due to their complicated chemistry, long life times, high mobility and prevailing anionic character. Therefore, knowledge of migration behaviour under different conditions can significantly improve input into performance and safety assessment models. Granite is considered as a potential host rock for deep geological disposal of radioactive waste in many countries. Granitic rocks consist usually of quartz, feldspar, plagioclase (main components), mica, chlorite, kaolinite (minor components). The main feature of the rock is advection governed transport in fractures, complemented with diffusion process from fracture towards undisturbed rock matrix. The presented work is focused on interaction of anionic species (TcO{sub 4}{sup -}, SeO{sub 4}{sup 2-}, SeO{sub 3}{sup 2-}) with granitic rock. Furthermore, the importance of mineral composition on sorption of anionic species was also studied. The batch sorption experiments were conducted on the crushed granite from Bohemian Massive. Five fractions with defined grain size were used for static batch method. Mineral composition of each granitic fraction was evaluated using X-ray diffraction. The results showed differences in composition of granitic fractions, even though originating from one homogenized material. Sorption experiments showed influence of granite composition on adsorption of both TcO4{sup -} and SeO3{sup 2-} on granitic rock. Generally, Se(IV) showed higher retention than Tc(VII). Se(VI) was not almost sorbed at all. Fe containing minerals are pronounced as a selective Se and Tc sorbent, being reduced on their surface. As micas in granite are usually enriched in Fe, increased sorption of anionic species onto mica enriched fractions can be explained by this reason. On the other hand

  7. Acceleration and novelty: community restoration speeds recovery and transforms species composition in Andean cloud forest.

    PubMed

    Wilson, Sarah Jane; Rhemtulla, Jeanine M

    2016-01-01

    Community-based tropical forest restoration projects, often promoted as a win-win solution for local communities and the environment, have increased dramatically in number in the past decade. Many such projects are underway in Andean cloud forests, which, given their extremely high biodiversity and history of extensive clearing, are understudied. This study investigates the efficacy of community-based tree-planting projects to accelerate cloud forest recovery, as compared to unassisted natural regeneration. This study takes place in northwest Andean Ecuador, where the majority of the original, highly diverse cloud forests have been cleared, in five communities that initiated tree-planting projects to restore forests in 2003. In 2011, we identified tree species along transects in planted forests (n = 5), naturally regenerating forests (n = 5), and primary forests (n = 5). We also surveyed 120 households about their restoration methods, tree preferences, and forest uses. We found that tree diversity was higher in planted than in unplanted secondary forest, but both were less diverse than primary forests. Ordination analysis showed that all three forests had distinct species compositions, although planted forests shared more species with primary forests than did unplanted forests. Planted forests also contained more animal-dispersed species in both the planted canopy and in the unplanted, regenerating understory than unplanted forests, and contained the highest proportion of species with use value for local people. While restoring forest increased biodiversity and accelerated forest recovery, restored forests may also represent novel ecosystems that are distinct from the region's previous ecosystems and, given their usefulness to people, are likely to be more common in the future. PMID:27039520

  8. Estimates of nuclear DNA content in red algal lineages

    PubMed Central

    Kapraun, Donald F.; Freshwater, D. Wilson

    2012-01-01

    Background and aims The red algae are an evolutionarily ancient group of predominantly marine organisms with an estimated 6000 species. Consensus higher-level molecular phylogenies support a basal split between the unicellular Cyanidiophytina and morphologically diverse Rhodophytina, the later subphylum containing most red algal species. The Rhodophytina is divided into six classes, of which five represent early diverging lineages of generally uninucleate species, whose evolutionary relationships are poorly resolved. The remaining species compose the large (27 currently recognized orders), morphologically diverse and typically multinucleate Florideophyceae. Nuclear DNA content estimates have been published for <1 % of the described red algae. The present investigation summarizes the state of our knowledge and expands our coverage of DNA content information from 196 isolates of red algae. Methodology The DNA-localizing fluorochrome DAPI (4′,6-diamidino-2-phenylindole) and RBC (chicken erythrocytes) standards were used to estimate 2C values with static microspectrophotometry. Principal results Nuclear DNA contents are reported for 196 isolates of red algae, almost doubling the number of estimates available for these organisms. Present results also confirm the reported DNA content range of 0.1–2.8 pg, with species of Ceramiales, Nemaliales and Palmariales containing apparently polyploid genomes with 2C = 2.8, 2.3 and 2.8 pg, respectively. Conclusions Early diverging red algal lineages are characterized by relatively small 2C DNA contents while a wide range of 2C values is found within the derived Florideophyceae. An overall correlation between phylogenetic placement and 2C DNA content is not apparent; however, genome size data are available for only a small portion of red algae. Current data do support polyploidy and aneuploidy as pervasive features of red algal genome evolution. PMID:22479676

  9. Constraints to commercialization of algal fuels.

    PubMed

    Chisti, Yusuf

    2013-09-10

    Production of algal crude oil has been achieved in various pilot scale facilities, but whether algal fuels can be produced in sufficient quantity to meaningfully displace petroleum fuels, has been largely overlooked. Limitations to commercialization of algal fuels need to be understood and addressed for any future commercialization. This review identifies the major constraints to commercialization of transport fuels from microalgae. Algae derived fuels are expensive compared to petroleum derived fuels, but this could change. Unfortunately, improved economics of production are not sufficient for an environmentally sustainable production, or its large scale feasibility. A low-cost point supply of concentrated carbon dioxide colocated with the other essential resources is necessary for producing algal fuels. An insufficiency of concentrated carbon dioxide is actually a major impediment to any substantial production of algal fuels. Sustainability of production requires the development of an ability to almost fully recycle the phosphorous and nitrogen nutrients that are necessary for algae culture. Development of a nitrogen biofixation ability to support production of algal fuels ought to be an important long term objective. At sufficiently large scale, a limited supply of freshwater will pose a significant limitation to production even if marine algae are used. Processes for recovering energy from the algal biomass left after the extraction of oil, are required for achieving a net positive energy balance in the algal fuel oil. The near term outlook for widespread use of algal fuels appears bleak, but fuels for niche applications such as in aviation may be likely in the medium term. Genetic and metabolic engineering of microalgae to boost production of fuel oil and ease its recovery, are essential for commercialization of algal fuels. Algae will need to be genetically modified for improved photosynthetic efficiency in the long term. PMID:23886651

  10. Substratum preference of two species of Xanthoparmelia.

    PubMed

    Deduke, Chris; Piercey-Normore, Michele D

    2015-09-01

    The distribution of established saxicolous lichens has been previously studied but substratum preference and elemental composition has been relatively unexplored. The objectives of this study were to compare ascospore germination and growth for two species of Xanthoparmelia using media supplemented with pulverized rock and to explore photobiont selectivity relative to ecological guilds. Mature apothecia from X. cumberlandia and X. viriduloumbrina were subjected to five treatments, which include water agar supplemented with crushed granodiorite, basalt, mica schist, dolostone, and malt yeast agar as the control. The algal actin gene was sequenced and the closest algal matches were retrieved from GenBank and analysed to produce a haplotype network. X. cumberlandia exhibited substratum preference for the mica schist treatment, while X. viriduloumbrina grew better on granodiorite and malt yeast agar relative to dolostone. Ascospore germination for both species failed to progress beyond the initial swelling and protrusion stage on the dolostone treatment. The actin gene sequences for the algae were most similar to those of Trebouxia jamesii. The rock substrates did not correspond with the photobiont haplotypes, which does not support the ecological guild hypothesis. This study provided insights into substratum preference and the suitability of the substratum for algal selection. PMID:26321730

  11. Effects of past burning frequency on plant species structure and composition in dry dipterocarp forest

    NASA Astrophysics Data System (ADS)

    Wanthongchai, Dr.; Bauhus, Prof.; Goldammer, Prof.

    2009-04-01

    Anthropogenic burning in dry dipterocarp forests (DDF) has become a common phenomenon throughout Thailand. It is feared that too frequent fires may affect vegetation structure and composition and thus impact on ecosystem productivity. The aim of this study was to quantify the effects of prescribed fires on sites with different past burning regimes on vegetation structure and composition in the Huay Kha Khaeng Wildlife Sanctuary (HKK), Thailand. Fire frequency was determined from satellite images and ranged from frequent, infrequent, rare and unburned with fire occurrences of 7, 2, 1 and 0 out of the past 10 years, respectively. The pre-burn fuel loads, the overstorey and understorey vegetation structure and composition were determined to investigate the effects of the contrasting past burning regimes. The burning experiment was carried out, applying a three-strip head-fire burning technique. The vegetation structure and composition were sampled again one year after the fire to assess the fire impacts. Aboveground fine fuel loads increased with the length of fire-free interval. The woody plant structures of the frequently burned stand differed from those of the other less frequently burned stands. The species composition of the overstorey on the frequently burned site, in particular that of small sized trees (4.5-10 cm dbh), also differed significantly from that of the other sites. Whilst the ground vegetation including shrubs and herbs did not differ between the past burning regimes, frequent burning obviously promoted the proliferation of graminoid vegetation. There was no clear evidence showing that the prescribed fires affected the mortality of trees (dbh> 4.5 cm) on the sites of the different past burning regimes. The effects of prescribed burning on the understorey vegetation structures varied between the past burning regimes and the understorey vegetation type. Therefore, it is recommended that the DDF at HKK should be subjected to a prescribed fire frequency

  12. Scale-dependent shifts in the species composition of flower visitors with changing floral density.

    PubMed

    Essenberg, Carla J

    2013-01-01

    Responses of flower-visiting animals to floral density can alter interactions between plants, influencing a variety of biological processes, including plant population dynamics and the evolution of flowering phenology. Many studies have found effects of floral or plant density on pollinator visitation rates at patch scales, but little is known about responses of flower visitors to floral densities at larger scales. Here, I present data from an observational field study in which I measured the effects of floral density on visitation to the annual composite Holocarpha virgata at both patch (4 m(2)) and site (12.6 ha) spatial scales. The species composition of flower visitors changed with floral density, and did so in different ways at the two scales. At the site scale, average floral density within patches of H. virgata or within patches of all summer-flowering species combined had a significant positive effect on per-flowerhead visitation by the long-horned bee Melissodes lupina and no significant effects on visitation by any other taxa. At the patch scale, per-flowerhead visitation by honeybees significantly increased whereas visitation by M. lupina often decreased with increasing floral density. For both species, responses to patch-scale floral density were strongest when site-scale floral density was high. The scale-dependence of flower visitor responses to floral density and the interactions between site- and patch-scale effects of floral density observed in this study underscore the importance of improving our understanding of pollinators' responses to floral density at population scales. PMID:22752187

  13. Assessing Historical Fish Community Composition Using Surveys, Historical Collection Data, and Species Distribution Models

    PubMed Central

    Labay, Ben; Cohen, Adam E.; Sissel, Blake; Hendrickson, Dean A.; Martin, F. Douglas; Sarkar, Sahotra

    2011-01-01

    Accurate establishment of baseline conditions is critical to successful management and habitat restoration. We demonstrate the ability to robustly estimate historical fish community composition and assess the current status of the urbanized Barton Creek watershed in central Texas, U.S.A. Fish species were surveyed in 2008 and the resulting data compared to three sources of fish occurrence information: (i) historical records from a museum specimen database and literature searches; (ii) a nearly identical survey conducted 15 years earlier; and (iii) a modeled historical community constructed with species distribution models (SDMs). This holistic approach, and especially the application of SDMs, allowed us to discover that the fish community in Barton Creek was more diverse than the historical data and survey methods alone indicated. Sixteen native species with high modeled probability of occurrence within the watershed were not found in the 2008 survey, seven of these were not found in either survey or in any of the historical collection records. Our approach allowed us to more rigorously establish the true baseline for the pre-development fish fauna and then to more accurately assess trends and develop hypotheses regarding factors driving current fish community composition to better inform management decisions and future restoration efforts. Smaller, urbanized freshwater systems, like Barton Creek, typically have a relatively poor historical biodiversity inventory coupled with long histories of alteration, and thus there is a propensity for land managers and researchers to apply inaccurate baseline standards. Our methods provide a way around that limitation by using SDMs derived from larger and richer biodiversity databases of a broader geographic scope. Broadly applied, we propose that this technique has potential to overcome limitations of popular bioassessment metrics (e.g., IBI) to become a versatile and robust management tool for determining status of

  14. Competition between macroalgae and corals: effects of herbivore exclusion and increased algal biomass on coral survivorship and growth

    NASA Astrophysics Data System (ADS)

    Lirman, D.

    2001-05-01

    Recent declines in coral abundance accompanied by increases in macroalgal cover on Florida reefs highlight the importance of competition for space between these groups. This paper documents the frequency of coral-algal interactions on the Northern Florida Reef Tract and evaluates the effects of grazer exclusions and experimental algal addition on growth and tissue mortality of three coral species, Siderastrea siderea, Porites astreoides, and Montastraea faveolata. The frequency of interactions between corals and macroalgae was high as more than 50% of the basal perimeter of colonies was in contact with macroalgae; turf forms, Halimeda spp., and Dictyota spp. were the most common groups in contact with corals. Decreased grazing pressure resulted in significant increases in algal biomass within cages, and caged corals showed species-specific susceptibility to increased algal biomass. While no effects were detected for S. siderea, significant decreases in growth rates were documented for caged P. astreoides which had growth rates three to four times lower than uncaged colonies. When an algal addition treatment was included to duplicate maximum algal biomass levels documented for reefs in the area, colonies of P. astreoides in the algal addition treatment had growth rates up to ten times lower than uncaged colonies. High susceptibility to algal overgrowth was also found for the reef-building coral M. faveolata, which experienced significant tissue mortality under both uncaged (5.2% decrease in live tissue area per month) and caged (10.2% per month) conditions. The documented effects of increased algal biomass on coral growth and tissue mortality suggest a potential threat for the long-term survivorship and growth of corals in the Florida Reef Tract if present rates of algal growth and space utilization are maintained.

  15. Slugs' last meals: molecular identification of sequestered chloroplasts from different algal origins in Sacoglossa (Opisthobranchia, Gastropoda).

    PubMed

    Händeler, Katharina; Wägele, Heike; Wahrmund, Ute; Rüdinger, Mareike; Knoop, Volker

    2010-11-01

    Some sacoglossan sea slugs have become famous for their unique capability to extract and incorporate functional chloroplasts from algal food organisms (mainly Ulvophyceae) into their gut cells. The functional incorporation of the so-called kleptoplasts allows the slugs to rely on photosynthetic products for weeks to months, enabling them to survive long periods of food shortage over most of their life-span. The algal food spectrum providing kleptoplasts as temporary, non-inherited endosymbionts appears to vary among sacoglossan slugs, but detailed knowledge is sketchy or unavailable. Accurate identification of algal donor species, which provide the chloroplasts for long-term retention is of primary importance to elucidate the biochemical mechanisms allowing long-term functionality of the captured chloroplast in the foreign animal cell environment. Whereas some sacoglossans forage on a variety of algal species, (e.g. Elysia crispata and E. viridis) others are more selective. Hence, characterizing the range of functional sacoglossan-chloroplast associations in nature is a prerequisite to understand the basis of this enigmatic endosymbiosis. Here, we present a suitable chloroplast gene (tufA) as a marker, which allows identification of the respective algal kleptoplast donor taxa by analysing DNA from whole animals. This novel approach allows identification of donor algae on genus or even species level, thus providing evidence for the taxonomic range of food organisms. We report molecular evidence that chloroplasts from different algal sources are simultaneously incorporated in some species of Elysia. NeigborNet analyses for species assignments are preferred over tree reconstruction methods because the former allow more reliable statements on species identification via barcoding, or rather visualize alternative allocations not to be seen in the latter. PMID:21565106

  16. Understanding how Seasonality and Shifts in Species Composition Impact Emission Estimates in Semi-Arid Ecosystems

    NASA Astrophysics Data System (ADS)

    Sparks, A.

    2012-12-01

    The importance of wildland fire as a source of trace gas emissions to the atmosphere has been demonstrated in the scientific literature and through numerous NASA funded campaigns to further understand the drivers and impacts of these emissions (e.g., SAFARI 1992, SAFARI 2000, TRACE A, etc). Most studies quantify the emissions using remotely sensed data through multiplying the area burned, the quantity of fuel combusted, and the emission factors of a given gas species (EFX, grams of gas, X, emitted per kilogram of fuel consumed). The latter is known to exhibit considerable uncertainty and indeed a prior study as part of NASA's SAFARI 2000 campaign highlighted a seasonal dependence of carbonaceous gas species emissions. Building off these past studies, the focus of the proposed research is to assess the influence of both seasonality and shifting vegetation composition (via replacement of native with invasive species), on the emissions of trace gases in semi-arid ecosystems. Emissions data will help lower emission factor uncertainties in sagebrush-steppe ecosystems as well as inform management decisions about the best burning times in a season (in terms of air quality and greenhouse gas production).

  17. Development of in-situ imaging tools to quantify vegetation stress, plant mortality, and species composition

    NASA Astrophysics Data System (ADS)

    Goulden, M.

    2014-12-01

    We have developed and deployed an imaging system at an eddy covariance site in a Southern California Pinyon-Juniper woodland; our goals are to quantify the species-level patterns of stress and mortality over time, and also to learn how to better interpret the Landsat record. Our imaging system combines a four channel spectrometer with cameras that are sensitive to Visible, Near Infrared (NIR), Shortwave Infrared (SWIR), and Thermal radiation; these cameras include filters that mimic the spectral sensitivity of several Landsat bands. The cameras and spectrometer foreoptic are positioned on a pan-tilt mount on the tower that scans a 300o x 90o area every hour and allows us to collect images of hundreds of distinct plants. The imaging system is being used to test several approaches that have been proposed to detect vegetation stress, mortality, and species composition. We are exploring the potential to detect stomatal closure and stress by: a) increased canopy temperature with decreased evaporative cooling, b) Photochemical Reflectance Index (PRI), c) Fraunhofer line fluorescence, and d) water band indices. Similarly, we are exploring the potential to detect plant mortality by: a) NIR reflectance, b) SWIR reflectance, and c) radiance temperature with soil exposure, and to identify plant species by: a) differential phenological and interannual patterns, b) spectral reflectance, and c) BRDF and the effect of solar angle.

  18. Composition of essential oils in subterranean organs of three species of Valeriana L.

    PubMed

    Samaneh, Ekhteraei Tousi; Tayebeh, Radjabian; Hassan, Ebrahimzadeh; Vahid, Niknam

    2010-11-01

    Essential oils from the subterranean organs of three species of Valeriana L. from Iran (Valeriana sisymbriifolia Vahl, Valeriana alliariifolia Adams and Valeriana officinalis L.) belonging to Valerianaceae family have been obtained by hydrodistillation and analysed by gas chromatography-mass spectrometry in order to discern the differences and similarities between the volatile chemical compositions of these species. More than 100 components were identified in essential oils of the studied plants (Supplementary Table S1--online only). The principal common constituents of the three species of Valeriana were spathulenol, limonene, γ-terpinene, vulgarone B and p-cymene. The main essential oil ingredients were α-selinene (7.83%) in V. sisymbriifolia, limonene (3.53%) in V. alliariifolia and spathulenol (13.33%), α-campholenal (11.48%), vulgarone B (8.38%) and valerenal (8.32%) in V. officinalis plants. Ageratochromene (precocene II), a chromene substance with antibacterial, antifungal, insecticidal and antijuvenile hormonal activities, was found at high levels (35.59% and 36.58%) in the essential oils of V. sisymbriifolia plants. PMID:21104529

  19. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    PubMed Central

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-01-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11 litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species. PMID:26515033

  20. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    NASA Astrophysics Data System (ADS)

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-10-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11 litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species.

  1. Modelling of compositional variation as a result of species transport during melt segregation

    NASA Astrophysics Data System (ADS)

    Solano, J.; Jackson, M.

    2011-12-01

    Models of magma formation and melt segregation in the deep crust often consider the coupled transport of heat and mass, but rarely consider species transport, i.e. the migration of major components and trace elements. As melt migrates relative to the matrix during melt segregation, compositional diversity, reflecting both the process and the thermal environment, can develop and plays an important role in determining the geochemical signature of any resultant magmas. Here, a model of heat, mass and both major component and trace element transport in a system undergoing buoyancy driven melt segregation (compaction) is presented. The model describes the phase behaviour of binary systems (both eutectic and solid solution) with the melt and solid compositions determined by temperature. Where melting relationships are required, they are determined from the phase diagram using the local temperature and bulk composition. Trace element concentrations can also be determined from the local bulk concentration and melt fraction. This model is applied to a number of different cases in which a one-dimensional column, with various different initial and boundary conditions, undergoes buoyancy driven melt segregation and this set up has been chosen as it most closely represents a case which could be repeated in a laboratory setting. In the simplest case, a perfectly insulated column with uniform initial temperature, melt fraction, composition and trace element concentration, is allowed to compact. As major components are transported, local melting and freezing take place. Variations in temperature the develop and the resulting bulk composition and trace element profiles differ from those predicted by models which do not consider binary systems, though this difference is small. Heterogeneous systems, in which the column initially has layers with different bulk compositions, have also been modelled. When melt migration takes place in these systems, mixing at the interface between the

  2. Factors determining parasite community richness and species composition in black snook Centropomus nigrescens (Centropomidae) from coastal lagoons in Guerrero, Mexico.

    PubMed

    Violante-González, Juan; Mendoza-Franco, Edgar F; Rojas-Herrera, Agustín; Gil Guerrero, Salvador

    2010-06-01

    Species richness and composition were determined for parasite communities in the black snook Centropomus nigrescens collected from five coastal lagoons in the Guerrero state, Mexico. A total of 354 fish were collected between December 2007 and November 2008. Twenty-four species of parasite were identified: 2 monogeneans, 12 digeneans, 4 acanthocephalans, 1 cestode, 4 nematodes, and 1 pentastomid. The communities consisted mainly of autogenic parasites, and all were dominated by the digenean Paracrytogonimus yamagutii. Community species composition was similar among lagoons, although the influence of local conditions prevented them from being identical. Host traits such as predator feeding habits, body size, and vagility contributed to parasite community structure and species composition. PMID:20336316

  3. Raman microspectroscopy based sensor of algal lipid unsaturation

    NASA Astrophysics Data System (ADS)

    Samek, Ota; Pilát, Zdeněk; Jonáš, Alexandr; Zemánek, Pavel; Šerý, Mojmír; Ježek, Jan; Bernatová, Silvie; Nedbal, Ladislav; Trtílek, Martin

    2011-05-01

    Raman spectroscopy is a powerful tool for chemical analysis. This technique can elucidate fundamental questions about the metabolic processes and intercellular variability on a single cell level. Therefore, Raman spectroscopy can significantly contribute to the study and use of microalgae in systems biology and biofuel technology. Raman spectroscopy can be combined with optical tweezers. We have employed microfluidic system to deliver the sampled microalgae to the Raman-tweezers. This instrument is able to measure chemical composition of cells and to track metabolic processes in vivo, in real-time and label-free making it possible to detect population variability in a wide array of traits. Moreover, employing an active sorting switch, cells can be separated depending on input parameters obtained from Raman spectra. We focus on algal lipids which are promising potential products for biofuel as well as for nutrition. Important parameter characterizing the algal lipids is the degree of unsaturation of the constituent fatty acids. We demonstrate the capacity of our Raman tweezers based sensor to sort cells according to the degree of unsaturation in lipid storage bodies of individual living algal cells.

  4. Biological Soil Crusts from Coastal Dunes at the Baltic Sea: Cyanobacterial and Algal Biodiversity and Related Soil Properties.

    PubMed

    Schulz, Karoline; Mikhailyuk, Tatiana; Dreßler, Mirko; Leinweber, Peter; Karsten, Ulf

    2016-01-01

    Biological soil crusts (BSCs) are known as "ecosystem-engineers" that have important, multifunctional ecological roles in primary production, in nutrient and hydrological cycles, and in stabilization of soils. These communities, however, are almost unstudied in coastal dunes of the temperate zone. Hence, for the first time, the biodiversity of cyanobacterial and algal dominated BSCs collected in five dunes from the southern Baltic Sea coast on the islands Rügen and Usedom (Germany) was investigated in connection with physicochemical soil parameters. The species composition of cyanobacteria and algae was identified with direct determination of crust subsamples, cultural methods, and diatom slides. To investigate the influence of soil properties on species composition, the texture, pH, electrical conductivity, carbonate content, total contents of carbon, nitrogen, phosphorus, and the bioavailable phosphorus-fraction (PO4 (3-)) were analyzed in adjacent BSC-free surface soils at each study site. The data indicate that BSCs in coastal dunes of the southern Baltic Sea represent an ecologically important vegetation form with a surprisingly high site-specific diversity of 19 cyanobacteria, 51 non-diatom algae, and 55 diatoms. All dominant species of the genera Coleofasciculus, Lyngbya, Microcoleus, Nostoc, Hydrocoryne, Leptolyngbya, Klebsormidium, and Lobochlamys are typical aero-terrestrial cyanobacteria and algae, respectively. This first study of coastal sand dunes in the Baltic region provides compelling evidence that here the BSCs were dominated by cyanobacteria, algae, or a mixture of both. Among the physicochemical soil properties, the total phosphorus content of the BSC-free sand was the only factor that significantly influenced the cyanobacterial and algal community structure of BSCs in coastal dunes. PMID:26507846

  5. CLIMATE CHANGE EFFECTS ON SPECIES COMPOSITION MEDIATES DECOMPOSITION IN AN OLD-FIELD ECOSYSTEM

    SciTech Connect

    Tyner, M.L.; Classen, A.T.

    2007-01-01

    Decomposition of leaf litter collected from an old-fi eld community grown under a combination of elevated atmospheric CO2 concentrations (+300ppm) and elevated surface temperature (+ 3.2°C) was examined in ambient conditions over 8 months in two separate experiments. In the fi rst experiment, we examined the main effects and interactions of CO2 and warming on litter quality and subsequent mass loss rates. Multi-species litter bags were constructed with litter collected from chambers with ambient CO2 and ambient temperatures (ACAT), elevated CO2 and elevated temperature (ECET), ambient CO2 and elevated temperature (ACET), and elevated CO2 and ambient temperature (ECAT). Litter collected from 6 species in each chamber was represented in decomposition bags in equal proportions. There were no differences in initial litter percent carbon (C) or nitrogen (N) among treatments. After 8 months, litter collected from ACET chambers lost over 20% more mass than litter collected from ECET or ACAT chambers, although biological differences were small. In the second experiment, we examined the indirect effect climate change may have on plant community composition, litter inputs, and subsequent mass loss rates. Litter bags were made from the same chambers mentioned above, but the amount of litter in the bag from each species was proportional to peak standing biomass of that species within the treatment. Initial litter in ECAT bags had up to 4% less C and 29% less N than ECET and ACET bags. Mass loss from ACET bags was 48% higher than mass loss from ECAT bags and 37% higher than mass loss from ACAT bags after 8 months of decomposition. These differences may have been driven by the higher proportion of litter from Lespedeza, a N-fi xer, in the natural ACET bags. Taken together, these data suggest that climate change will have a larger effect on decomposition by causing shifts in plant communities than it will by altering litter quality.

  6. Quantifying Phytogeographical Regions of Australia Using Geospatial Turnover in Species Composition

    PubMed Central

    González-Orozco, Carlos E.; Ebach, Malte C.; Laffan, Shawn; Thornhill, Andrew H.; Knerr, Nunzio J.; Schmidt-Lebuhn, Alexander N.; Cargill, Christine C.; Clements, Mark; Nagalingum, Nathalie S.; Mishler, Brent D.; Miller, Joseph T.

    2014-01-01

    The largest digitized dataset of land plant distributions in Australia assembled to date (750,741 georeferenced herbarium records; 6,043 species) was used to partition the Australian continent into phytogeographical regions. We used a set of six widely distributed vascular plant groups and three non-vascular plant groups which together occur in a variety of landscapes/habitats across Australia. Phytogeographical regions were identified using quantitative analyses of species turnover, the rate of change in species composition between sites, calculated as Simpson's beta. We propose six major phytogeographical regions for Australia: Northern, Northern Desert, Eremaean, Eastern Queensland, Euronotian and South-Western. Our new phytogeographical regions show a spatial agreement of 65% with respect to previously defined phytogeographical regions of Australia. We also confirm that these new regions are in general agreement with the biomes of Australia and other contemporary biogeographical classifications. To assess the meaningfulness of the proposed phytogeographical regions, we evaluated how they relate to broad scale environmental gradients. Physiographic factors such as geology do not have a strong correspondence with our proposed regions. Instead, we identified climate as the main environmental driver. The use of an unprecedentedly large dataset of multiple plant groups, coupled with an explicit quantitative analysis, makes this study novel and allows an improved historical bioregionalization scheme for Australian plants. Our analyses show that: (1) there is considerable overlap between our results and older biogeographic classifications; (2) phytogeographical regions based on species turnover can be a powerful tool to further partition the landscape into meaningful units; (3) further studies using phylogenetic turnover metrics are needed to test the taxonomic areas. PMID:24658356

  7. Quantifying phytogeographical regions of Australia using geospatial turnover in species composition.

    PubMed

    González-Orozco, Carlos E; Ebach, Malte C; Laffan, Shawn; Thornhill, Andrew H; Knerr, Nunzio J; Schmidt-Lebuhn, Alexander N; Cargill, Christine C; Clements, Mark; Nagalingum, Nathalie S; Mishler, Brent D; Miller, Joseph T

    2014-01-01

    The largest digitized dataset of land plant distributions in Australia assembled to date (750,741 georeferenced herbarium records; 6,043 species) was used to partition the Australian continent into phytogeographical regions. We used a set of six widely distributed vascular plant groups and three non-vascular plant groups which together occur in a variety of landscapes/habitats across Australia. Phytogeographical regions were identified using quantitative analyses of species turnover, the rate of change in species composition between sites, calculated as Simpson's beta. We propose six major phytogeographical regions for Australia: Northern, Northern Desert, Eremaean, Eastern Queensland, Euronotian and South-Western. Our new phytogeographical regions show a spatial agreement of 65% with respect to previously defined phytogeographical regions of Australia. We also confirm that these new regions are in general agreement with the biomes of Australia and other contemporary biogeographical classifications. To assess the meaningfulness of the proposed phytogeographical regions, we evaluated how they relate to broad scale environmental gradients. Physiographic factors such as geology do not have a strong correspondence with our proposed regions. Instead, we identified climate as the main environmental driver. The use of an unprecedentedly large dataset of multiple plant groups, coupled with an explicit quantitative analysis, makes this study novel and allows an improved historical bioregionalization scheme for Australian plants. Our analyses show that: (1) there is considerable overlap between our results and older biogeographic classifications; (2) phytogeographical regions based on species turnover can be a powerful tool to further partition the landscape into meaningful units; (3) further studies using phylogenetic turnover metrics are needed to test the taxonomic areas. PMID:24658356

  8. Direct and indirect effects of high pCO2 on algal grazing by coral reef herbivores from the Gulf of Aqaba (Red Sea)

    NASA Astrophysics Data System (ADS)

    Borell, E. M.; Steinke, M.; Fine, M.

    2013-12-01

    Grazing on marine macroalgae is a key structuring process for coral reef communities. However, ocean acidification from rising atmospheric CO2 concentrations is predicted to adversely affect many marine animals, while seaweed communities may benefit and prosper. We tested how exposure to different pCO2 (400, 1,800 and 4,000 μatm) may affect grazing on the green alga Ulva lactuca by herbivorous fish and sea urchins from the coral reefs in the northern Gulf of Aqaba (Red Sea), either directly, by changing herbivore behaviour, or indirectly via changes in algal palatability. We also determined the effects of pCO2 on algal tissue concentrations of protein and the grazing-deterrent secondary metabolite dimethylsulfoniopropionate (DMSP). Grazing preferences and overall consumption were tested in a series of multiple-choice feeding experiments in the laboratory and in situ following exposure for 14 d (algae) and 28 d (herbivores). 4,000 μatm had a significant effect on the biochemical composition and palatability of U. lactuca. No effects were observed at 1,800 relative to 400 μatm (control). Exposure of U. lactuca to 4,000 μatm resulted in a significant decrease in protein and increase in DMSP concentration. This coincided with a reduced preference for these algae by the sea urchin Tripneustes gratilla and different herbivorous fish species in situ (Acanthuridae, Siganidae and Pomacanthidae). No feeding preferences were observed for the rabbitfish Siganus rivulatus under laboratory conditions. Exposure to elevated pCO2 had no direct effect on the overall algal consumption by T. gratilla and S. rivulatus. Our results show that CO2 has the potential to alter algal palatability to different herbivores which could have important implications for algal abundance and coral community structure. The fact that pCO2 effects were observed only at a pCO2 of 4,000 μatm, however, indicates that algal-grazer interactions may be resistant to predicted pCO2 concentrations in the

  9. Soil Disturbance as a Grassland Restoration Measure—Effects on Plant Species Composition and Plant Functional Traits

    PubMed Central

    Schnoor, Tim; Bruun, Hans Henrik; Olsson, Pål Axel

    2015-01-01

    Soil disturbance is recognized as an important driver of biodiversity in dry grasslands, and can therefore be implemented as a restoration measure. However, because community re-assembly following disturbance includes stochastic processes, a focus only on species richness or establishment success of particular species will not inform on how plant communities respond ecologically to disturbance. We therefore evaluated vegetation development following disturbance by quantifying species richness, species composition and functional trait composition. Degraded calcareous sandy grassland was subjected to experimental disturbance treatments (ploughing or rotavation), and the vegetation was surveyed during four subsequent years of succession. Treated plots were compared with control plots representing untreated grassland, as well as nearby plots characterized by plant communities representing the restoration target. Species richness and functional diversity both increased in response to soil disturbance, and rotavation, but not ploughing, had a persistent positive effect on the occurrence of specialist species of calcareous sandy grassland. However, no type of soil disturbance caused the plant species composition to develop towards the target vegetation. The disturbance had an immediate and large impact on the vegetation, but the vegetation developed rapidly back towards the control sites. Plant functional composition analysis indicated that the treatments created habitats different both from control sites and target sites. Community-weighted mean Ellenberg indicator values suggested that the observed plant community response was at least partially due to an increase in nitrogen and water availability following disturbance. This study shows that a mild type of disturbance, such as rotavation, may be most successful in promoting specialist species in calcareous sandy grassland, but that further treatments are needed to reduce nutrient availability. We conclude that a

  10. Micro-structured surfaces for algal biofilm growth

    NASA Astrophysics Data System (ADS)

    Sathananthan, Suthamathy; Genin, Scott N.; Aitchison, J. Stewart; Allen, D. Grant

    2013-12-01

    It is well known that cells respond to structured surface cues that are on the micro/nanometer scale. Tissue engineering and bio-fouling fields have utilized the semiconductor device fabrication processes to make micro- and nanometer patterned surfaces to study animal cell tissue formation and to prevent algae attachment on marine surfaces respectively. In this paper we describe the use of micro-structured surfaces to study the attachment and growth of algal films. This paper gives an overview of how micro-structured surfaces are made for this purpose, how they are incorporated into a photo bioreactor and how this patterning influences the growth of an algal biofilm. Our results suggest that surface patterning with deeper V-groove patterns that are of the same size scale as the algal species has resulted in higher biomass productivity giving them a chance to embed and attach on the slope and flat surfaces whereas shallower size grooves and completely flat surfaces did not show this trend.

  11. Study of cnidarian-algal symbiosis in the "omics" age.

    PubMed

    Meyer, Eli; Weis, Virginia M

    2012-08-01

    The symbiotic associations between cnidarians and dinoflagellate algae (Symbiodinium) support productive and diverse ecosystems in coral reefs. Many aspects of this association, including the mechanistic basis of host-symbiont recognition and metabolic interaction, remain poorly understood. The first completed genome sequence for a symbiotic anthozoan is now available (the coral Acropora digitifera), and extensive expressed sequence tag resources are available for a variety of other symbiotic corals and anemones. These resources make it possible to profile gene expression, protein abundance, and protein localization associated with the symbiotic state. Here we review the history of "omics" studies of cnidarian-algal symbiosis and the current availability of sequence resources for corals and anemones, identifying genes putatively involved in symbiosis across 10 anthozoan species. The public availability of candidate symbiosis-associated genes leaves the field of cnidarian-algal symbiosis poised for in-depth comparative studies of sequence diversity and gene expression and for targeted functional studies of genes associated with symbiosis. Reviewing the progress to date suggests directions for future investigations of cnidarian-algal symbiosis that include (i) sequencing of Symbiodinium, (ii) proteomic analysis of the symbiosome membrane complex, (iii) glycomic analysis of Symbiodinium cell surfaces, and (iv) expression profiling of the gastrodermal cells hosting Symbiodinium. PMID:22983032

  12. Chemical composition and fuel wood characteristics of fast growing tree species in India

    NASA Astrophysics Data System (ADS)

    Chauhan, S. K.; Soni, R.

    2012-04-01

    India is one of the growing economy in the world and energy is a critical input to sustain the growth of development. Country aims at security and efficiency of energy. Though fossil fuel will continue to play a dominant role in energy scenario but country is committed to global environmental well being thus stressing on environment friendly technologies. Concerns of energy security in this changing climatic situation have led to increasing support for the development of new renewable source of energy. Government though is determined to facilitate bio-energy and many projects have been established but initial after-affects more specifically on the domestic fuelwood are evident. Even the biomass power generating units are facing biomass crisis and accordingly the prices are going up. The CDM projects are supporting the viability of these units resultantly the Indian basket has a large number of biomass projects (144 out of total 506 with 28 per cent CERs). The use for fuelwood as a primary source of energy for domestic purpose by the poor people (approx. 80 per cent) and establishment of bio-energy plants may lead to deforestation to a great extent and only solution to this dilemma is to shift the wood harvest from the natural forests to energy plantations. However, there is conspicuous lack of knowledge with regards to the fuelwood characteristics of fast growing tree species for their selection for energy plantations. The calorific value of the species is important criteria for selection for fuel but it is affected by the proportions of biochemical constituents present in them. The aim of the present work was to study the biomass production, calorific value and chemical composition of different short rotation tree species. The study was done from the perspective of using the fast growing tree species for energy production at short rotation and the study concluded that short rotation tree species like Gmelina arborea, Eucalyptus tereticornis, Pongamia pinnata

  13. Sterol composition of shellfish species commonly consumed in the United States

    PubMed Central

    Phillips, Katherine M.; Ruggio, David M.; Exler, Jacob; Patterson, Kristine Y.

    2012-01-01

    Background Shellfish can be a component of a healthy diet due to a low fat and high protein content, but the cholesterol content of some species is often cited as a reason to limit their consumption. Data on levels of non-cholesterol sterols in commonly consumed species are lacking. Objective Shellfish were sampled and analyzed to update sterol data in the United States Department of Agriculture (USDA) National Nutrient Database for Standard Reference. Design Using a nationwide sampling plan, raw shrimp and sea scallops, canned clams, and steamed oysters, blue crab, and lobster were sampled from 12 statistically selected supermarkets across the United States in 2007–08. For each species, four composites were analyzed, each comprised of samples from three locations; shrimp and scallops from six single locations were also analyzed separately. Using validated analytical methodology, 14 sterols were determined in total lipid extracts after saponification and derivatization to trimethylsilyethers, using gas chromatography for quantitation and mass spectrometry for confirmation of components. Results Crab, lobster, and shrimp contained significant cholesterol (96.2–27 mg/100 g); scallops and clams had the lowest concentrations (23.4–30.1 mg/100 g). Variability in cholesterol among single-location samples of shrimp was low. The major sterols in the mollusks were brassicasterol (12.6–45.6 mg/100 g) and 24-methylenecholesterol (16.7–41.9 mg/100 g), with the highest concentrations in oysters. Total non-cholesterol sterols were 46.5–75.6 mg/100 g in five single-location scallops samples, but 107 mg/100 g in the sixth, with cholesterol also higher in that sample. Other prominent non-cholesterol sterols in mollusks were 22-dehydrocholesterol, isofucosterol, clionasterol, campesterol, and 24-norcholesta-5,22-diene-3β-ol (4–21 mg/100 g). Conclusions The presence of a wide range of sterols, including isomeric forms, in shellfish makes the analysis and quantitation

  14. [Species composition of agents of the horsetail common (Equisetum arvense L.) bacteriosises].

    PubMed

    Iakovleva, L M; Patyka, V F; Shcherbina, T N; Savenko, E A

    2012-01-01

    Bacterial diseases of weeds horsetail common (Equisetum arvense L.) were revealed in the crops of wheat and soya in the fields of Kyiv and Vinnitsia Regions of Ukraine. The distinctive symptoms of bacterial affections on the root neck, on stalks of vegetative and spore shoots, on twigs were brown, dark brown or almost black necrotic spots of oblong form. The necroses increased in size, embraced the stalks. The stalks broke, the plants dried up. Patterns of affected plants, isolated and identified phytopathogenic bacteria Pseudomonas syringae, Pectobacterium carotovorum subsp. carotovorum, Pantoea agglomerans and Curtobacterium sp. were analyzed These bacteria caused pathological process on the horsetail common, wheat and soy under the conditions of artificial inoculation. The composition of bacteria species was different in different years depending on temperature conditions of vegetative period. PMID:22830194

  15. Chemical composition and antigerminative activity of the essential oils from five Salvia species.

    PubMed

    De Martino, Laura; Roscigno, Graziana; Mancini, Emilia; De Falco, Enrica; De Feo, Vincenzo

    2010-02-01

    The chemical composition of the essential oils of Salvia africana L., Salvia elegans Vahl, Salvia greggii A. Gray, Salvia mellifera Green and Salvia munzii Epling, cultivated in Eboli (Salerno, Southern Italy), was studied by means of GC and GC-MS analyses. In all, 88 compounds were identified, 54 for S. africana, accounting for 95.4% of the total oil, 55 for S. elegans (92.9%), 50 for S. greggii (96.9%), 54 for S. mellifera (90.4%) and 47 for S. munzii (97.5%), respectively. In S. africana,the amount of monoterpenoids and sesquiterpenoids is very similar. For other species, the monoterpenoid percentage is greater than the amount of sesquiterpenoids. The oils of S. elegans, S. greggii and S. munzii were active inhibitors of germination and radical elongation of Raphanus sativus L. and Lepidium sativum L. PMID:20335942

  16. Exploring the Utilization of Complex Algal Communities to Address Algal Pond Crash and Increase Annual Biomass Production for Algal Biofuels

    SciTech Connect

    Hamilton, Cyd E.

    2014-03-25

    This white paper briefly reviews the research literature exploring complex algal communities as a means of increasing algal biomass production via increased tolerance, resilience, and resistance to a variety of abiotic and biotic perturbations occurring within harvesting timescales. This paper identifies what data are available and whether more research utilizing complex communities is needed to explore the potential of complex algal community stability (CACS) approach as a plausible means to increase biomass yields regardless of ecological context and resulting in decreased algal-based fuel prices by reducing operations costs. By reviewing the literature for what we do and do not know, in terms of CACS methodologies, this report will provide guidance for future research addressing pond crash phenomena.

  17. Chemical Composition, Nitrogen Fractions and Amino Acids Profile of Milk from Different Animal Species.

    PubMed

    Rafiq, Saima; Huma, Nuzhat; Pasha, Imran; Sameen, Aysha; Mukhtar, Omer; Khan, Muhammad Issa

    2016-07-01

    Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat (6.82%±0.04%), solid-not-fat (11.24%±0.02%), total solids (18.05%±0.05%), protein (5.15%±0.06%) and casein (3.87%±0.04%) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk (0.80%±0.03%), buffalo (0.68%±0.02%) and sheep (0.66%±0.02%) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow (108±2.3 mg/g), camel (96±2.2 mg/g) and buffalo (90±2.4 mg/g) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products. PMID:26954163

  18. Chemical Composition, Nitrogen Fractions and Amino Acids Profile of Milk from Different Animal Species

    PubMed Central

    Rafiq, Saima; Huma, Nuzhat; Pasha, Imran; Sameen, Aysha; Mukhtar, Omer; Khan, Muhammad Issa

    2016-01-01

    Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat (6.82%±0.04%), solid-not-fat (11.24%±0.02%), total solids (18.05%±0.05%), protein (5.15%±0.06%) and casein (3.87%±0.04%) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk (0.80%±0.03%), buffalo (0.68%±0.02%) and sheep (0.66%±0.02%) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow (108±2.3 mg/g), camel (96±2.2 mg/g) and buffalo (90±2.4 mg/g) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products. PMID:26954163

  19. Essential oil composition from two species of Piperaceae family grown in Colombia.

    PubMed

    Pino Benitez, Nayive; Meléndez León, Erika M; Stashenko, Elena E

    2009-10-01

    Essential oil compositions of aerial parts from two species in the Piper (Piperaceae family) genera: Piper lanceaefolium Kunth and Piper hispidum Sw., frequently called deflated (for the anti-inflammatory activity) or cord. Piperaceae leaves were collected in different regions of the Chocó department in northwestern Colombia and identified by botanists from Colombian National Herbarium, where a voucher of each specimen were deposited (No- COL 519993 and No- COL 519969, respectively). The essential oils were obtained by microwave-assisted hydrodistillation (MWHD) and analyzed by gas chromatography-mass spectrometry (GC-MS). The P. lanceaefolium essential oil was sesquiterpenoid type (71.7%). This composition was represented by sesquiterpenes hydrocarbons (58.5%) and by their oxygenated derivates (13.2%); the main compounds were, trans-beta-caryophyllene (11.6%) and germacrene D (10.7%) followed by alpha-selinene (7.8%), beta-pinene (5.4%), beta-selinene (4.8%), and alpha-cubebene (4.3%). The Piper hispidum essential oil also was sesquiterpene type (74.4%) and oxygenated sesquiterpenes (46.4%) followed by sesquiterpenes hydrocarbons (28.0%). The main compounds were trans-nerolidol (23.6%) and caryophyllene oxide (5.4%) followed by beta-elemene (5.1%), trans-beta-caryophyllene (5.1%), curzerene (4.9%), and germacrene B (4.5%). Trans-beta-caryophyllene presents the higher percentage of the common compounds in the two species' essential oil (11.6% and 5.1% in P. lanceaefolium and P. hispidum, respectively). PMID:19835693

  20. Evaluating algal growth performance and water use efficiency of pilot-scale revolving algal biofilm (RAB) culture systems.

    PubMed

    Gross, Martin; Mascarenhas, Vernon; Wen, Zhiyou

    2015-10-01

    A Revolving Algal Biofilm (RAB) growth system in which algal cells are attached to a flexible material rotating between liquid and gas phases has been developed. In this work, different configurations of RAB systems were developed at pilot-scale by retrofitting the attachment materials to a raceway pond (2000-L with 8.5 m(2) footprint area) and a trough reservoir (150 L with 3.5 m(2) footprint area). The algal growth performance and chemical composition, as well as the water evaporative loss and specific water consumption were evaluated over a period of nine months in a greenhouse environment near Boone, Iowa USA. Additionally a raceway pond was run in parallel, which served as a control. On average the raceway-based RAB and the trough-based RAB outperformed the control pond by 309% and 697%, respectively. A maximum productivity of 46.8 g m(-2) day(-1) was achieved on the trough-based RAB system. The evaporative water loss of the RAB system was modeled based on an energy balance analysis and was experimentally validated. While the RAB system, particularly the trough-based RAB, had higher water evaporative loss, the specific water consumption per unit of biomass produced was only 26% (raceway-based RAB) and 7% (trough-based RAB) of that of the control pond. Collectively, this research shows that the RAB system is an efficient algal culture system and has great potential to commercially produce microalgae with high productivity and efficient water use. PMID:25899246

  1. Implications of nutrient removal and biomass production by native and augmented algal populations at a municipal wastewater treatment plant.

    PubMed

    Drexler, Ivy L C; Bekaan, Sascha; Eskandari, Yasmin; Yeh, Daniel H

    2014-01-01

    Algal monocultures (Chlorella sorokiniana and Botryococcus braunii) and algal communities native to clarifiers of a wastewater treatment plant were batch cultivated in (1) clarified effluent following a biochemical oxygen demand (BOD) removal reactor post-BOD removal clarified effluent (PBCE), (2) clarified effluent following a nitrification reactor post-nitrification clarified effluent (PNCE), and (3) a reference media (RM). After 12 days, all algal species achieved nitrogen removal between 68 and 82% in PBCE and 37 and 99% in PNCE, and phosphorus removal between 91 and 100% in PBCE and 60 and 100% in PNCE. The pH of the wastewater samples increased above 9.8 after cultivation of each species, which likely aided ammonia volatilization and phosphorus adsorption. Both monocultures grew readily with wastewater as a feedstock, but B. braunii experienced significant crowding from endemic fauna. In most cases, native algal species' nutrient removal efficiency was competitive with augmented algal monocultures, and in some cases achieved a higher biomass yield, demonstrating the potential to utilize native species for nutrient polishing and algal biomass production. PMID:25325538

  2. Study on bending behavior of ionic polymer metal composites with various organic solvents and cationic species

    NASA Astrophysics Data System (ADS)

    Nam, Byung K.; Yoo, Youngtai

    2005-05-01

    Ion exchange polymer metal composites (IPMC) are electro-active actuators that show large deformation in the presence of low applied voltage. Perfluorosulfonic acid membrane, Nafion, is one of the most widely studied materials for this purpose. Experimental studies were carried out on the bending behavior of Nafion-based IPMCs containing various solvents and cation species. Various counter cations of sulfonate groups in the membrane were obtained by soaking the composite membrane in aqueous salt solutions. The salts used in ion exchange process include LiOH, NaOH, Cu(NO3)2, Co(NO3)2. Ion-exchange capacity of the IPMC was measured by ICP. In the case of cationic effect the Li-form IPMC demonstrated an immediate and efficient deformation behavior at 1 DC V, while divalent cuprous cation containing IPMC exhibited the larger tip displacement at an elevated electric potential. A threshold electric driving force appears to be required for cations with large hydration and high volume. IPMCs were also prepared by soaking in various transport media. The solutions were prepared by adding 1 mole of NMP, DMF, DMSO, and PEG 200 in water. The feasibility of D2O was also investigated. Addition of organic polar solvents in water decreases the dielectric constant of medium, which subsequently reduces the dissociation of ion pairs. Among the various solutions the heavy water, D2O and DMSO/water (1 Mole/L) mixture demonstrated unusually stable tendency in terms of electrolysis.

  3. Chemical and biochemical composition of caviar from different sturgeon species and origins.

    PubMed

    Wirth, M; Kirschbaum, F; Gessner, J; Krüger, A; Patriche, N; Billard, R

    2000-08-01

    The chemical and biochemical composition of caviar in 22 specimens of wild caught and of 2 farmed animals were measured. The results include grain size, protein and fat content, fatty acid composition of triglycerides and phospholipids, as well as the concentrations of relevant heavy metals and chlorinated hydrocarbons. The average protein content varied between 26.2 and 31.1% (wet weight) and fat from 10.9 to 19.4% (wet weight) with lowest values for caviar from farmed sturgeon. The triglycerides and phospholipids contained more n-3 fatty acids, especially eicosapentaenoic and docosahexaenoic acid than n-6 fatty acids. The copper and zinc concentrations varied between 1.20 and 1.69 and 10.3 and 12.4 mg/kg (wet weight), respectively. These values reflect the elevated requirement of sturgeons for these components. Lead content varied between 0.06 and 0.15 mg/kg (wet weight). The cadmium concentrations were less than 5 micrograms/kg (wet weight) leading to the conclusion that no accumulation took place in the eggs. The concentrations of sigma DDT and sigma PCB were extremely high in caviar from Huso huso compared to the samples of the other species thus reflecting the different food habits leading to increased bio-accumulation. PMID:10996895

  4. Acidification of the humic Lake Skjervatjern; effects on the volume and species composition of phytoplankton

    SciTech Connect

    Brettum, P. )

    1994-01-01

    This paper presents the effects of the experimental acidification on the volume and composition of phytoplankton from the investigations carried out in Lake Skjervatjern in connection with the HUMEX project. The results of the phytoplankton analysis are presented from Basin A, the acidified basin, and Basin B, the control, two years before the acidification started and two years during the acidification. In Basin B, the control basin, the succession of the main groups of phytoplankton throughout the growth season remained almost identical from year to year in the investigation period. The development of the phytoplankton was almost the same in the two basins before the acidification started. The results from the acidified Basin A in 1991 and 1992 show marked changes and an almost immediate response in the phytoplankton composition and percentage of the main algae groups, compared to the reference basin. The percentage of the green algae decreased, especially the species Oocystis submarina v. variabilis, while the dinoflagellate Peridinium inconspicuum and the cryptomonads increased in number and percentage of the total volume in the acidified basin. The total volume and the primary production measurements show an increase in Basin A compared to the control in the first year of acidification treatment (1991), but a decrease in the next year. 30 refs., 6 figs., 1 tab.

  5. Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae) in coffee agroecosystems.

    PubMed

    Pérez, Jeanneth; Virgen, Armando; Rojas, Julio Cesar; Rebollar-Téllez, Eduardo Alfonso; Alfredo, Castillo; Infante, Francisco; Mikery, Oscar; Marina, Carlos Felix; Ibáñez-Bernal, Sergio

    2014-02-01

    The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.)], Finca Argovia (613 m a.s.l.) and Teotihuacán del Valle (429 m a.s.l.). Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp. PMID:24271002

  6. Species composition and seasonal abundance of sandflies (Diptera: Psychodidae: Phlebotominae) in coffee agroecosystems

    PubMed Central

    Pérez, Jeanneth; Virgen, Armando; Rojas, Julio Cesar; Rebollar-Téllez, Eduardo Alfonso; Alfredo, Castillo; Infante, Francisco; Mikery, Oscar; Marina, Carlos Felix; Ibáñez-Bernal, Sergio

    2013-01-01

    The composition and seasonal occurrence of sandflies were investigated in coffee agroecosystems in the Soconusco region of Chiapas, Mexico. Insect sampling was performed on three plantations located at different altitudes: Finca Guadalupe Zajú [1,000 m above sea level (a.s.l.)], Finca Argovia (613 m a.s.l.) and Teotihuacán del Valle (429 m a.s.l.). Sandflies were sampled monthly from August 2007-July 2008 using three sampling methods: Shannon traps, CDC miniature light traps and Disney traps. Sampling was conducted for 3 h during three consecutive nights, beginning at sunset. A total of 4,387 sandflies were collected during the course of the study: 2,718 individuals in Finca Guadalupe Zajú, 605 in Finca Argovia and 1,064 in Teotihuacán del Valle. The Shannon traps captured 94.3% of the total sandflies, while the CDC light traps and Disney traps captured 4.9% and 0.8%, respectively. More females than males were collected at all sites. While the number of sandflies captured was positively correlated with temperature and relative humidity, a negative correlation was observed between sandfly numbers and rainfall. Five species of sandflies were captured: Lutzomyia cruciata , Lutzomyia texana , Lutzomyia ovallesi , Lutzomyia cratifer / undulata and Brumptomyia sp. Lu. cruciata , constituting 98.8% of the total, was the most abundant species. None of the captured sandflies was infected with Leishmania spp. PMID:24271002

  7. Lipid content and fatty acid composition of 11 species of Queensland (Australia) fish.

    PubMed

    Belling, G B; Abbey, M; Campbell, J H; Campbell, G R

    1997-06-01

    The fatty acid composition of 11 species of fish caught of the northeast coast of Australia was determined. No fatty acid profiles have been previously published for fish from this area nor for nine of these species. Although the percentage of polyunsaturated fatty acid (PUFA) was the same as the calculated average for Australian fish (42.3%), the percentage of n-3 fatty acids was lower (24.4 +/- 5.4% vs. 30.7 +/- 10.1%) and the n-6 fatty acids higher (16.5 +/- 4.5% vs. 11.2 +/- 5.9%), P < 0.001 in each case. The major n-3 PUFA were docosahexaenoic (15.6 +/- 6.3%) and eicosapentaenoic acid (4.3 +/- 1.1%) while the major n-6 PUFA were arachidonic (8.3 +/- 3.2%) and n-6 docosatetraenoic acid (3.1 +/- 1.3%). The second-most abundant class of fatty acid was the saturates (31.6 +/- 3.5%) while the monounsaturates accounted for 17.4 +/- 4.3% of the total fatty acids. The monounsaturate with the highest concentration was octadecenoic acid (11.8 +/- 2.6%). There was a positive correlation between the total lipid content and saturated and monounsaturated fatty acids (r = 0.675 and 0.567, respectively) and a negative correlation between the total lipid content and PUFA (r = 0.774). PMID:9208391

  8. Fish composition and species richness in eastern South American coastal lagoons: additional support for the freshwater ecoregions of the world.

    PubMed

    Petry, A C; Guimarães, T F R; Vasconcellos, F M; Hartz, S M; Becker, F G; Rosa, R S; Goyenola, G; Caramaschi, E P; Díaz de Astarloa, J M; Sarmento-Soares, L M; Vieira, J P; Garcia, A M; Teixeira de Mello, F; de Melo, F A G; Meerhoff, M; Attayde, J L; Menezes, R F; Mazzeo, N; Di Dario, F

    2016-07-01

    The relationships between fish composition, connectivity and morphometry of 103 lagoons in nine freshwater ecoregions (FEOW) between 2·83° S and 37·64° S were evaluated in order to detect possible congruence between the gradient of species richness and similarities of assemblage composition. Most lagoons included in the study were <2 km(2) , with a maximum of 3975 km(2) in surface area. Combined surface area of all lagoons included in the study was 5411 km(2) . Number of species varied locally from one to 76. A multiple regression revealed that latitude, attributes of morphometry and connectivity, and sampling effort explained a large amount of variability in species richness. Lagoon area was a good predictor of species richness except in low latitude ecoregions, where lagoons are typically small-sized and not affected by marine immigrants, and where non-native fish species accounted for a significant portion of species richness. Relationships between species and area in small-sized lagoons (<2 km(2) ) is highly similar to the expected number in each ecoregion, with systems located between 18·27° S and 30·15° S attaining higher levels of species richness. Similarities in species composition within the primary, secondary and peripheral or marine divisions revealed strong continental biogeographic patterns only for species less tolerant or intolerant to salinity. Further support for the FEOW scheme in the eastern border of South America is therefore provided, and now includes ecotonal systems inhabited simultaneously by freshwater and marine species of fishes. PMID:27401481

  9. Remote Sensing Marine Ecology: Wind-driven algal blooms in the open oceans and their ecological impacts

    NASA Astrophysics Data System (ADS)

    Tang, DanLing

    2016-07-01

    Algal bloom not only can increase the primary production but also could result in negative ecological consequence, e.g., Harmful Algal Blooms (HABs). According to the classic theory for the formation of algal blooms "critical depth" and "eutrophication", oligotrophic sea area is usually difficult to form a large area of algal blooms, and actually the traditional observation is only sporadic capture to the existence of algal blooms. Taking full advantage of multiple data of satellite remote sensing, this study: 1), introduces "Wind-driven algal blooms in open oceans: observation and mechanisms" It explained except classic coastal Ekman transport, the wind through a variety of mechanisms affecting the formation of algal blooms. Proposed a conceptual model of "Strong wind -upwelling-nutrient-phytoplankton blooms" in Western South China Sea (SCS) to assess role of wind-induced advection transport in phytoplankton bloom formation. It illustrates the nutrient resources that support long-term offshore phytoplankton blooms in the western SCS; 2), Proposal of the theory that "typhoons cause vertical mixing, induce phytoplankton blooms", and quantify their important contribution to marine primary production; Proposal a new ecological index for typhoon. Proposed remote sensing inversion models. 3), Finding of the spatial and temporaldistributions pattern of harmful algal bloom (HAB)and species variations of HAB in the South Yellow Sea and East China Sea, and in the Pearl River estuary, and their oceanic dynamic mechanisms related with monsoon; The project developed new techniques and generated new knowledge, which significantly improved understanding of the formation mechanisms of algal blooms. 1), It proposed "wind-pump" mechanism integrates theoretical system combing "ocean dynamics, development of algal blooms, and impact on primary production", which will benefit fisheries management. 2), A new interdisciplinary subject "Remote Sensing Marine Ecology"(RSME) has been

  10. The Ecuadorian Artisanal Fishery for Large Pelagics: Species Composition and Spatio-Temporal Dynamics.

    PubMed

    Martínez-Ortiz, Jimmy; Aires-da-Silva, Alexandre M; Lennert-Cody, Cleridy E; Maunder, Mark N

    2015-01-01

    The artisanal fisheries of Ecuador operate within one of the most dynamic and productive marine ecosystems of the world. This study investigates the catch composition of the Ecuadorian artisanal fishery for large pelagic fishes, including aspects of its spatio-temporal dynamics. The analyses of this study are based on the most extensive dataset available to date for this fishery: a total of 106,963 trip-landing inspection records collected at its five principal ports during 2008 ‒ 2012. Ecuadorian artisanal fisheries remove a substantial amount of biomass from the upper trophic-level predatory fish community of the eastern tropical Pacific Ocean. It is estimated that at least 135 thousand metric tons (mt) (about 15.5 million fish) were landed in the five principal ports during the study period. The great novelty of Ecuadorian artisanal fisheries is the "oceanic-artisanal" fleet component, which consists of mother-ship (nodriza) boats with their towed fiber-glass skiffs (fibras) operating with pelagic longlines. This fleet has fully expanded into oceanic waters as far offshore as 100°W, west of the Galapagos Archipelago. It is estimated that nodriza operations produce as much as 80% of the total catches of the artisanal fishery. The remainder is produced by independent fibras operating in inshore waters with pelagic longlines and/or surface gillnets. A multivariate regression tree analysis was used to investigate spatio-environmental effects on the nodriza fleet (n = 6,821 trips). The catch species composition of the nodriza fleet is strongly influenced by the northwesterly circulation of the Humboldt Current along the coast of Peru and its associated cold waters masses. The target species and longline gear-type used by nodrizas change seasonally with the incursion of cool waters (< 25°C) from the south and offshore. During this season, dolphinfish (Coryphaena hippurus) dominates the catches. However, in warmer waters, the fishery changes to tuna

  11. The Ecuadorian Artisanal Fishery for Large Pelagics: Species Composition and Spatio-Temporal Dynamics

    PubMed Central

    Martínez-Ortiz, Jimmy; Aires-da-Silva, Alexandre M.; Lennert-Cody, Cleridy E.; Maunder, Mark N.

    2015-01-01

    The artisanal fisheries of Ecuador operate within one of the most dynamic and productive marine ecosystems of the world. This study investigates the catch composition of the Ecuadorian artisanal fishery for large pelagic fishes, including aspects of its spatio-temporal dynamics. The analyses of this study are based on the most extensive dataset available to date for this fishery: a total of 106,963 trip-landing inspection records collected at its five principal ports during 2008 ‒ 2012. Ecuadorian artisanal fisheries remove a substantial amount of biomass from the upper trophic-level predatory fish community of the eastern tropical Pacific Ocean. It is estimated that at least 135 thousand metric tons (mt) (about 15.5 million fish) were landed in the five principal ports during the study period. The great novelty of Ecuadorian artisanal fisheries is the “oceanic-artisanal” fleet component, which consists of mother-ship (nodriza) boats with their towed fiber-glass skiffs (fibras) operating with pelagic longlines. This fleet has fully expanded into oceanic waters as far offshore as 100°W, west of the Galapagos Archipelago. It is estimated that nodriza operations produce as much as 80% of the total catches of the artisanal fishery. The remainder is produced by independent fibras operating in inshore waters with pelagic longlines and/or surface gillnets. A multivariate regression tree analysis was used to investigate spatio-environmental effects on the nodriza fleet (n = 6,821 trips). The catch species composition of the nodriza fleet is strongly influenced by the northwesterly circulation of the Humboldt Current along the coast of Peru and its associated cold waters masses. The target species and longline gear-type used by nodrizas change seasonally with the incursion of cool waters (< 25°C) from the south and offshore. During this season, dolphinfish (Coryphaena hippurus) dominates the catches. However, in warmer waters, the fishery changes to tuna

  12. Monitoring of Water Quality and Microalgae Species Composition of Penaeus monodon Ponds in Pulau Pinang, Malaysia

    PubMed Central

    Shaari, Asma Liyana; Surif, Misni; Latiff, Faazaz Abd.; Omar, Wan Maznah Wan; Ahmad, Mohd Noor

    2011-01-01

    Many reports have revealed that the abundance of microalgae in shrimp ponds vary with changes in environmental factors such as light, temperature, pH, salinity and nutrient level throughout a shrimp culture period. In this study, shrimp cultivation period was divided into three stages (initial = week 0–5, mid = week 6–10 and final = week 11–15). Physical and chemical parameters throughout the cultivation period were studied and species composition of microalgae was monitored. Physical parameters were found to fluctuate widely with light intensity ranging between 182.23–1278 μmol photon m−2s−1, temperature between 29.56°C −31.59°C, dissolved oxygen (DO) between 4.56–8.21 mg/l, pH between 7.65–8.49 and salinity between 20‰–30‰. Ammonium (NH4+-N), nitrite (NO2−-N), nitrate (NO3−-N), and orthophosphate (PO43−-P) concentrations in the pond at all cultivation stages ranged from 0.017 to 0.38 mg/l, 0.24 to 2.12 mg/l, 0.06 to 0.98 mg/l and 0.16 to 1.93 mg/l respectively. Statistical test (ANOVA) showed that there were no significant difference (p<0.05) in nutrients concentrations among the cultivation stages. All nutrients concentrations however were still in the tolerable level and safe for shrimp culture. The chlorophyll a contents were found to range from 5.03±2.17 to 32.61±0.35 μg/l throughout the cultivation period. A total of 19 microalgae species were found in the shrimp pond, with diatoms contributing up to 72% of the species followed by Chlorophyta (11%) and Cyanophyta (11%). However, weekly species abundance varied through the study period. At the initial stage, when there were no shrimps in the pond, Anabaena spp. and Oscillatoria spp. (Cyanophyta) were the dominant species, followed by Chlorella sp. and Dunaliella sp. (Chlorophyta). When shrimps were introduced into the pond, Amphora sp., Navicula sp. Gyrosigma sp. and Nitzschia sp. (diatoms) started to exist. At the middle and towards the final stage of the shrimp culture

  13. High Frequency Monitoring for Harmful Algal Blooms

    EPA Science Inventory

    Harmful algal blooms (HABs) are increasingly becoming a significant ecologic, economic, and social driver in the use of water resources. Cyanobacteria and their toxins play an important role in management decisions for drinking water utilities and public health officials. Online ...

  14. Algal bioassessment metrics for wadeable streams and rivers of Maine, USA

    USGS Publications Warehouse

    Danielson, T.J.; Loftin, C.S.; Tsomides, L.; Difranco, J.L.; Connors, B.

    2011-01-01

    Many state water-quality agencies use biological assessment methods based on lotic fish and macroinvertebrate communities, but relatively few states have incorporated algal multimetric indices into monitoring programs. Algae are good indicators for monitoring water quality because they are sensitive to many environmental stressors. We evaluated benthic algal community attributes along a landuse gradient affecting wadeable streams and rivers in Maine, USA, to identify potential bioassessment metrics. We collected epilithic algal samples from 193 locations across the state. We computed weighted-average optima for common taxa for total P, total N, specific conductance, % impervious cover, and % developed watershed, which included all land use that is no longer forest or wetland. We assigned Maine stream tolerance values and categories (sensitive, intermediate, tolerant) to taxa based on their optima and responses to watershed disturbance. We evaluated performance of algal community metrics used in multimetric indices from other regions and novel metrics based on Maine data. Metrics specific to Maine data, such as the relative richness of species characterized as being sensitive in Maine, were more correlated with % developed watershed than most metrics used in other regions. Few community-structure attributes (e.g., species richness) were useful metrics in Maine. Performance of algal bioassessment models would be improved if metrics were evaluated with attributes of local data before inclusion in multimetric indices or statistical models. ?? 2011 by The North American Benthological Society.

  15. Direct conversion of algal biomass to biofuel

    DOEpatents

    Deng, Shuguang; Patil, Prafulla D; Gude, Veera Gnaneswar

    2014-10-14

    A method and system for providing direct conversion of algal biomass. Optionally, the method and system can be used to directly convert dry algal biomass to biodiesels under microwave irradiation by combining the reaction and combining steps. Alternatively, wet algae can be directly processed and converted to fatty acid methyl esters, which have the major components of biodiesels, by reacting with methanol at predetermined pressure and temperature ranges.

  16. Alkenone distribution in Lake Van sediment over the last 270 ka: influence of temperature and haptophyte species composition

    NASA Astrophysics Data System (ADS)

    Randlett, Marie-Ève; Coolen, Marco J. L.; Stockhecke, Mona; Pickarski, Nadine; Litt, Thomas; Balkema, Cherel; Kwiecien, Ola; Tomonaga, Yama; Wehrli, Bernhard; Schubert, Carsten J.

    2014-11-01

    Fossil long-chain alkenones have been used for several decades to reconstruct past ocean surface water temperatures and gained recent interest as a paleotemperature proxy for continental lake settings. However, factors besides temperature can affect alkenone distributions in haptophyte algae, and alkenone compositions can differ between haptophyte species. Alkenone-biosynthesizing haptophyte algae are genetically much more diverse in lakes than in the marine realm, and species-level variations in alkenone compositions could have implications for alkenone paleothermometry. Here, we performed a paired analysis of alkenone distributions and haptophyte species compositions using ancient DNA in up to 270 ka-old sediments of Lake Van in Turkey to reveal a possible species-effect on fossil alkenone distributions and paleotemperature estimates. The same predominant haptophyte in Lake Van today prevailed also since the last ˜100 ka. However, a calibration of alkenone paleotemperature especially in the oldest analyzed intervals is complicated due to a more complex haptophyte species composition predominated by a haptophyte (LVHap_6), which is phylogenetically different from sequences recovered from currently existing lakes including Lake Van and from haptophyte species existing in culture. The predominance of LVHap_6 coincided with the presence of alkenone MeC38:3 and relatively high MeC37:3/4 (2.4) and MeC38:4/5 ratios (3.0). Uk37 index values in the sediment core over the last 270 ka reflect relative changes in past temperature and are additionally linked to haptophyte species composition. A sustained period of high salinity, as indicated by pore-water salinity measurements, could potentially have triggered the succession of haptophytes as sources of alkenones in Lake Van.

  17. Development of algal interspecies correlation estimation models for chemical hazard assessment.

    PubMed

    Brill, Jessica L; Belanger, Scott E; Chaney, Joel G; Dyer, Scott D; Raimondo, Sandy; Barron, Mace G; Pittinger, Charles A

    2016-09-01

    Web-based Interspecies Correlation Estimation (ICE) is an application developed to predict the acute toxicity of a chemical from 1 species to another taxon. Web-ICE models use the acute toxicity value for a surrogate species to predict effect values for other species, thus potentially filling in data gaps for a variety of environmental assessment purposes. Web-ICE has historically been dominated by aquatic and terrestrial animal prediction models. Web-ICE models for algal species were essentially absent and are addressed in the present study. A compilation of public and private sector-held algal toxicity data were compiled and reviewed for quality based on relevant aspects of individual studies. Interspecies correlations were constructed from the most commonly tested algal genera for a broad spectrum of chemicals. The ICE regressions were developed based on acute 72-h and 96-h endpoint values involving 1647 unique studies on 476 unique chemicals encompassing 40 genera and 70 species of green, blue-green, and diatom algae. Acceptance criteria for algal ICE models were established prior to evaluation of individual models and included a minimum sample size of 3, a statistically significant regression slope, and a slope estimation parameter ≥0.65. A total of 186 ICE models were possible at the genus level, with 21 meeting quality criteria; and 264 ICE models were developed at the species level, with 32 meeting quality criteria. Algal ICE models will have broad utility in screening environmental hazard assessments, data gap filling in certain regulatory scenarios, and as supplemental information to derive species sensitivity distributions. Environ Toxicol Chem 2016;35:2368-2378. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. PMID:26792236

  18. Low temporal variation in the intact polar lipid composition of North Sea coastal marine water reveals limited chemotaxonomic value

    NASA Astrophysics Data System (ADS)

    Brandsma, J.; Hopmans, E. C.; Philippart, C. J. M.; Veldhuis, M. J. W.; Schouten, S.; Sinninghe Damsté, J. S.

    2012-03-01

    Temporal variations in the abundance and composition of intact polar lipids (IPLs) in North Sea coastal marine water were assessed over a one-year seasonal cycle, and compared with environmental parameters and the microbial community composition. Sulfoquinovosyldiacylglycerol (SQDG) was the most abundant IPL class, followed by phosphatidylcholine (PC), phosphatidylglycerol (PG) and diacylglyceryl-(N,N,N)-trimethylhomoserine (DGTS) in roughly equal concentrations, and smaller amounts of phosphatidylethanolamine (PE). Although the total concentrations of these IPL classes varied substantially throughout the year, the composition of the IPL pool remained remarkably constant. Statistical analysis yielded negative correlations between IPL concentrations and dissolved inorganic nutrient concentrations, but no changes in the overall planktonic IPL composition due to nutrient limitation were observed. Significant correlations between SQDG, PC, PG and DGTS concentrations and chlorophyll a concentrations and algal abundances indicated that eukaryotic primary producers, in particular Phaeocystis globosa, were the predominant source of IPLs at this site. However, while IPL concentrations in the water were closely tied to total algal abundances, the rapid succession of different algal groups blooming throughout the year resulted in only minor shifts in the IPL composition. Principal component analysis showed that the IPLs were derived from multiple sources, and that no IPL species could be exclusively assigned to a particular algal taxa or (cyano)bacteria. Thus, the most commonly occurring IPLs appear to have limited chemotaxonomic potential, highlighting the need to use targeted assays of more specific biomarker IPLs.

  19. Soil-occupancy effects of invasive and native grassland plant species on composition and diversity of mycorrhizal associations

    USGS Publications Warehouse

    Jordan, Nicholas R.; Aldrich-Wolfe, Laura; Huerd, Sheri C.; Larson, Diane L.; Muehlbauer, Gary

    2012-01-01

    Diversified grasslands that contain native plant species can produce biofuels, support sustainable grazing systems, and produce other ecosystem services. However, ecosystem service production can be disrupted by invasion of exotic perennial plants, and these plants can have soil-microbial “legacies” that may interfere with establishment and maintenance of diversified grasslands even after effective management of the invasive species. The nature of such legacies is not well understood, but may involve suppression of mutualisms between native species and soil microbes. In this study, we tested the hypotheses that legacy effects of invasive species change colonization rates, diversity, and composition of arbuscular-mycorrhizal fungi (AMF) associated with seedlings of co-occurring invasive and native grassland species. In a glasshouse, experimental soils were conditioned by cultivating three invasive grassland perennials, three native grassland perennials, and a native perennial mixture. Each was grown separately through three cycles of growth, after which we used T-RFLP analysis to characterize AMF associations of seedlings of six native perennial and six invasive perennial species grown in these soils. Legacy effects of soil conditioning by invasive species did not affect AMF richness in seedling roots, but did affect AMF colonization rates and the taxonomic composition of mycorrhizal associations in seedling roots. Moreover, native species were more heavily colonized by AMF and roots of native species had greater AMF richness (number of AMF operational taxonomic units per seedling) than did invasive species. The invasive species used to condition soil in this experiment have been shown to have legacy effects on biomass of native seedlings, reducing their growth in this and a previous similar experiment. Therefore, our results suggest that successful plant invaders can have legacies that affect soil-microbial associations of native plants and that these effects

  20. Phytochemical Composition, Antioxidant Activity and HPLC Fingerprinting Profiles of Three Pyrola Species from Different Regions

    PubMed Central

    Wang, Dongmei; He, Fengyuan; Lv, Zhenjiang; Li, Dengwu

    2014-01-01

    The present study was performed to investigate the variation of phytochemical composition, antioxidant activity and High Performance Liquid Chromatography (HPLC) fingerprinting profiles of three Pyrola species. Thirteen samples (eight P. decorata, three P. calliantha and two P. renifolia) were collected from different regions in China. The tannin, hyperoside and quercetin contents of all samples were determined by reverse-phase HPLC and varied within the range 9.77–34.75, 0.34–2.16 and 0.062–0.147 mg/g dry weigh, respectively. Total flavonoid content was evaluated and varied within the range 16.22–37.82 mg/g dry weight. Antioxidant activity was determined by DPPH assay, with IC50 ranging from 7.96 to 50.33 µg/ml, ABTS•+ and FRAP assay, within the range 612.66–1021.05 and 219.64–398.12 µmol equiv. Trolox/g, respectively. These results revealed that there were significant variations in phytochemical profiles and antioxidant activity among all samples. Due to the higher phytochemical content and significant antioxidant activity, P. calliantha was selected as the most valuable species, and the P. calliantha sample from Left banner of Alxa even possessed the strongest antioxidant activity among all the thirteen samples. Futhermore, Emei Mountain was proved to be the most suitable region for producing P. decorata. Moreover, in order to further evaluate the diversities and quality of Pyrola, HPLC fingerprint analysis coupled with hierarchical cluster and discrimination analyses were introduced to establish a simple, rapid and effective method for accurate identification, classification and quality assessment of Pyrola. Thirteen samples were divided into three groups consistent with their morphological classification. Two types of discriminant functions were generated and the ratio of discrimination was 100%. This method can identify different species of Pyrola and the same species from different regions of origin. Also, it can be used to compare and

  1. Marine mimivirus relatives are probably large algal viruses

    PubMed Central

    Monier, Adam; Larsen, Jens Borggaard; Sandaa, Ruth-Anne; Bratbak, Gunnar; Claverie, Jean-Michel; Ogata, Hiroyuki

    2008-01-01

    Background Acanthamoeba polyphaga mimivirus is the largest known ds-DNA virus and its 1.2 Mb-genome sequence has revealed many unique features. Mimivirus occupies an independent lineage among eukaryotic viruses and its known hosts include only species from the Acanthamoeba genus. The existence of mimivirus relatives was first suggested by the analysis of the Sargasso Sea metagenomic data. Results We now further demonstrate the presence of numerous "mimivirus-like" sequences using a larger marine metagenomic data set. We also show that the DNA polymerase sequences from three algal viruses (CeV01, PpV01, PoV01) infecting different marine algal species (Chrysochromulina ericina, Phaeocystis pouchetii, Pyramimonas orientalis) are very closely related to their homolog in mimivirus. Conclusion Our results suggest that the numerous mimivirus-related sequences identified in marine environments are likely to originate from diverse large DNA viruses infecting phytoplankton. Micro-algae thus constitute a new category of potential hosts in which to look for new species of Mimiviridae. PMID:18215256

  2. Rapid inventory of the ant assemblage in a temperate hardwood forest: species composition and assessment of sampling methods.

    PubMed

    Ellison, Aaron M; Record, Sydne; Arguello, Alexander; Gotelli, Nicholas J

    2007-08-01

    Ants are key indicators of ecological change, but few studies have investigated how ant assemblages respond to dramatic changes in vegetation structure in temperate forests. Pests and pathogens are causing widespread loss of dominant canopy tree species; ant species composition and abundance may be very sensitive to such losses. Before the experimental removal of red oak trees to simulate effects of sudden oak death and examine the long-term impact of oak loss at the Black Rock Forest (Cornwall, NY), we carried out a rapid assessment of the ant assemblage in a 10-ha experimental area. We also determined the efficacy in a northern temperate forest of five different collecting methods--pitfall traps, litter samples, tuna fish and cookie baits, and hand collection--routinely used to sample ants in tropical systems. A total of 33 species in 14 genera were collected and identified; the myrmecines, Aphaenogaster rudis and Myrmica punctiventris, and the formicine Formica neogagates were the most common and abundant species encountered. Ninety-four percent (31 of 33) of the species were collected by litter sampling and structured hand sampling together, and we conclude that, in combination, these two methods are sufficient to assess species richness and composition of ant assemblages in northern temperate forests. Using new, unbiased estimators, we project that 38-58 ant species are likely to occur at Black Rock Forest. Loss of oak from these forests may favor Camponotus species that nest in decomposing wood and open habitat specialists in the genus Lasius. PMID:17716467

  3. Microflotation performance for algal separation.

    PubMed

    Hanotu, James; Bandulasena, H C Hemaka; Zimmerman, William B

    2012-07-01

    The performance of microflotation, dispersed air flotation with microbubble clouds with bubble size about 50 µm, for algae separation using fluidic oscillation for microbubble generation is investigated. This fluidic oscillator converts continuous air supply into oscillatory flow with a regular frequency to generate bubbles of the scale of the exit pore. Bubble characterization results showed that average bubble size generated under oscillatory air flow state was 86 µm, approximately twice the size of the diffuser pore size of 38 µm. In contrast, continuous air flow at the same rate through the same diffusers yielded an average bubble size of 1,059 µm, 28 times larger than the pore size. Following microbubble generation, the separation of algal cells under fluidic oscillator generated microbubbles was investigated by varying metallic coagulant types, concentration and pH. Best performances were recorded at the highest coagulant dose (150 mg/L) applied under acidic conditions (pH 5). Amongst the three metallic coagulants studied, ferric chloride yielded the overall best result of 99.2% under the optimum conditions followed closely by ferric sulfate (98.1%) and aluminum sulfate with 95.2%. This compares well with conventional dissolved air flotation (DAF) benchmarks, but has a highly turbulent flow, whereas microflotation is laminar with several orders of magnitude lower energy density. PMID:22290221

  4. Sterol phylogenesis and algal evolution

    SciTech Connect

    Nes, W.D.; Norton, R.A.; Crumley, F.G. ); Madigan, S.J.; Katz, E.R. )

    1990-10-01

    The stereochemistry of several sterol precursors and end products synthesized by two fungal-like microorganisms Prototheca wickerhamii (I) and Dictyostelium discoideum (II) have been determined by chromatographic (TLC, GLC, and HPLC) and spectral (UV, MS, and {sup 1}H NMR) methods. From I and II the following sterols were isolated from the cells: cycloartenol, cyclolaudenol, 24(28)-methylenecy-cloartanol, ergosterol, protothecasterol, 4{alpha}-methylergostanol, 4{alpha}-methylclionastanol, clionastanol, 24{beta}-ethylcholesta-8,22-enol, and dictyosterol. In addition, the mechanism of C-24 methylation was investigated in both organisms by feeding to I (2-{sup 3}H)lanosterol, (2-{sup 3}H)cycloartenol, (24{sup 3}H)lanosterol, and (methyl-{sup 2}H{sub 3})methionine and by feeding to II (methyl-{sup 2}H{sub 3})methionine. The results demonstrate that the 24{beta} configuration is formed by different alkylation routes in I and II. The authors conclude that Prototheca is an apoplastic Chlorella (i.e., an alga) and that Dictyostelium as well as the other soil amoebae that synthesize cycloartenol evolved from algal rather than fungal ancestors.

  5. Responses of algal communities to gradients in herbivore biomass and water quality in Marovo Lagoon, Solomon Islands

    NASA Astrophysics Data System (ADS)

    Albert, S.; Udy, J.; Tibbetts, I. R.

    2008-03-01

    Settlement tiles were used to characterise and quantify coral reef associated algal communities along water quality and herbivory gradients from terrestrial influenced near shore sites to oceanic passage sites in Marovo Lagoon, the Solomon Islands. After 6 months, settlement tile communities from inshore reefs were dominated by high biomass algal turfs (filamentous algae and cyanobacteria) whereas tiles located on offshore reefs were characterised by a mixed low biomass community of calcareous crustose algae, fleshy crustose algae and bare tile. The exclusion of macrograzers, via caging of tiles, on the outer reef sites resulted in the development of an algal turf community similar to that observed on inshore reefs. Caging on the inshore reef tiles had a limited impact on community composition or biomass. Water quality and herbivorous fish biomass were quantified at each site to elucidate factors that might influence algal community structure across the lagoon. Herbivore biomass was the dominant driver of algal community structure. Algal biomass on the other hand was controlled by both herbivory and water quality (particularly dissolved nutrients). This study demonstrates that algal communities on settlement tiles are an indicator capable of integrating the impacts of water quality and herbivory over a small spatial scale (kilometres) and short temporal scale (months), where other environmental drivers (current, light, regional variability) are constant.

  6. The habitats exploited and the species trapped in a Caribbean island trap fishery

    USGS Publications Warehouse

    Garrison, V.H.; Rogers, C.S.; Beets, J.; Friedlander, A.M.

    2004-01-01

    We visually observed fish traps in situ to identify the habitats exploited by the U.S. Virgin Islands fishery and to document species composition and abundance in traps by habitat. Fishers set more traps in algal plains than in any other habitat around St. John. Coral reefs, traditionally targeted by fishers, accounted for only 16% of traps. Traps in algal plain contained the highest number of fishes per trap and the greatest numbers of preferred food species. Traps on coral reefs contained the most species, 41 of the 59 taxa observed in the study. Acanthurus coeruleus was the most abundant species and Acanthuridae the most abundant family observed in traps. Piscivore numbers were low and few serranids were observed. Traps in algal plain contained the most fishes as a result of: ecological changes such as shifts in habitat use, mobility of species and degradation of nearshore habitat (fishery independent); and, catchability of fishes and long-term heavy fishing pressure (fishery dependent). The low number of serranids per trap, dominance of the piscivore guild by a small benthic predator, Epinephelus guttatus, and dominance of trap contents overall by a small, fast-growing species of a lower trophic guild, Acanthurus coeruleus, all point to years of intense fishing pressure.

  7. Algal remediation of CO₂ and nutrient discharges: A review.

    PubMed

    Judd, Simon; van den Broeke, Leo J P; Shurair, Mohamed; Kuti, Yussuf; Znad, Hussein

    2015-12-15

    The recent literature pertaining to the application of algal photobioreactors (PBRs) to both carbon dioxide mitigation and nutrient abatement is reviewed and the reported data analysed. The review appraises the influence of key system parameters on performance with reference to (a) the absorption and biological fixation of CO2 from gaseous effluent streams, and (b) the removal of nutrients from wastewaters. Key parameters appraised individually with reference to CO2 removal comprise algal speciation, light intensity, mass transfer, gas and hydraulic residence time, pollutant (CO2 and nutrient) loading, biochemical and chemical stoichiometry (including pH), and temperature. Nutrient removal has been assessed with reference to hydraulic residence time and reactor configuration, along with C:nutrient ratios and other factors affecting carbon fixation, and outcomes compared with those reported for classical biological nutrient removal (BNR). Outcomes of the review indicate there has been a disproportionate increase in algal PBR research outputs over the past 5-8 years, with a significant number of studies based on small, bench-scale systems. The quantitative impacts of light intensity and loading on CO2 uptake are highly dependent on the algal species, and also affected by solution chemical conditions such as temperature and pH. Calculations based on available data for biomass growth rates indicate that a reactor CO2 residence time of around 4 h is required for significant CO2 removal. Nutrient removal data indicate residence times of 2-5 days are required for significant nutrient removal, compared with <12 h for a BNR plant. Moreover, the shallow depth of the simplest PBR configuration (the high rate algal pond, HRAP) means that its footprint is at least two orders of magnitude greater than a classical BNR plant. It is concluded that the combined carbon capture/nutrient removal process relies on optimisation of a number of process parameters acting synergistically

  8. Inhibition of Alkaline Flocculation by Algal Organic Matter for Chlorella vulgaris

    SciTech Connect

    Vandamme, Dries; Beuckels, Annelies; Vadelius, Eric; Depraetere, Orily; Noppe, Wim; Dutta, Abhishek; Foubert, Imogen; Laurens, Lieve; Muylaert, Koenraad

    2016-01-01

    Alkaline flocculation is a promising strategy for the concentration of microalgae for bulk biomass production. However, previous studies have shown that biological changes during the cultivation negatively affect flocculation efficiency. The influence of changes in cell properties and in the quality and composition of algal organic matter (AOM) were studied using Chlorella vulgaris as a model species. In batch cultivation, flocculation was increasingly inhibited over time and mainly influenced by changes in medium composition, rather than biological changes at the cell surface. Total carbohydrate content of the organic matter fraction sized bigger than 3 kDa increased over time and this fraction was shown to be mainly responsible for the inhibition of alkaline flocculation. The monosaccharide identification of this fraction mainly showed the presence of neutral and anionic monosaccharides. An addition of 30–50 mg L-1 alginic acid, as a model for anionic carbohydrate polymers containing uronic acids, resulted in a complete inhibition of flocculation. Furthermore, these results suggest that inhibition of alkaline flocculation was caused by interaction of anionic polysaccharides leading to an increased flocculant demand over time.

  9. Inhibition of alkaline flocculation by algal organic matter for Chlorella vulgaris.

    PubMed

    Vandamme, Dries; Beuckels, Annelies; Vadelius, Eric; Depraetere, Orily; Noppe, Wim; Dutta, Abhishek; Foubert, Imogen; Laurens, Lieve; Muylaert, Koenraad

    2016-01-01

    Alkaline flocculation is a promising strategy for the concentration of microalgae for bulk biomass production. However, previous studies have shown that biological changes during the cultivation negatively affect flocculation efficiency. The influence of changes in cell properties and in the quality and composition of algal organic matter (AOM) were studied using Chlorella vulgaris as a model species. In batch cultivation, flocculation was increasingly inhibited over time and mainly influenced by changes in medium composition, rather than biological changes at the cell surface. Total carbohydrate content of the organic matter fraction sized bigger than 3 kDa increased over time and this fraction was shown to be mainly responsible for the inhibition of alkaline flocculation. The monosaccharide identification of this fraction mainly showed the presence of neutral and anionic monosaccharides. The addition of 30-50 mg L(-1) alginic acid, as a model for anionic carbohydrate polymers containing uronic acids, resulted in a complete inhibition of flocculation. These results suggest that inhibition of alkaline flocculation was caused by interaction of anionic polysaccharides leading to an increased flocculant demand over time. PMID:26512808

  10. Composition of headspace volatiles and essential oils of three Thymus species.

    PubMed

    Stojanović, Gordana; Jovanović, Olga; Petrović, Goran; Mitić, Violeta; Jovanović, Vesna Stankov; Jovanović, Snežana

    2014-11-01

    Analysis of head space volatiles (HSV) and hydrodistilled essential oils (EO) of the above-ground parts of Thymus glabrescens Willd., T. praecox Opiz subsp. jankae (Celak.) Jalas (from two localities) and T. pulegoides L. was made by GC-FID and GC-MS. This is the first report on the headspace volatiles composition of T. glabrescens and T. pulegoides. The most abundant compound of T. glabrescens HSV was p-cymene (27.8%) followed by γ-terpinene (18.4%), while thymol (55.4%) and geraniol (10.5%) were the most abundant in the corresponding EO. T. praecox subsp. jankae EO from Serbia was characterized by (E)-caryophyllene (14.6%) and thymol (10.7%), which is substantially different from that of Bulgarian T. praecox subsp. jankae, which contained a-terpinyl acetate (20.1%) and linalool (17.7%) as its main components. The dominating components of the Serbian and Bulgarian T. praecox subsp. jankae HSV were α-pinene (29.4% and 18.6%, respectively), myrcene (12.1% and 23.2%, respectively), limonene (7.5% and 17.8%, respectively) and β-pinene (11.7% and 7.6%, respectively). Linalyl acetate predominated in T. pulegoides EO and HSV, representing 40.0% and 42.4% (respectively) of the total peak area. The chemical composition of the essential oils of the examined Thymus species could not be attributed to any particular recorded chemotype of T. glabrescens, T. praecox and T. pulegoides. PMID:25532293

  11. Algal Accessory Pigment Detection Using AVIRIS Image-Derived Spectral Radiance Data

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Ambrosia, Vincent G.

    1996-01-01

    Visual and derivative analyses of AVIRIS spectral data can be used to detect algal accessory pigments in aquatic communities. This capability extends the use of remote sensing for the study of aquatic ecosystems by allowing detection of taxonomically significant pigment signatures which yield information about the type of algae present. Such information allows remote sensing-based assessment of aquatic ecosystem health, as in the detection of nuisance blooms of cyanobacteria or toxic blooms of dinoflagellates. Remote sensing of aquatic systems has traditionally focused on quantification of chlorophyll a, a photoreactive (and light-harvesting) pigment which is common to all algae as well as cyanobacteria (bluegreen algae). Due to the ubiquitousness of this pigment within algae, chl a is routinely measured to estimate algal biomass both during ground-truthing and using various airborne or satellite based sensors, including AVIRIS. Within the remote sensing and aquatic sciences communities, ongoing research has been performed to detect algal accessory pigments for assessment of algal population composition. This research is based on the fact that many algal accessory pigments are taxonomically significant, and all are spectrally unique. Aquatic scientists have been refining pigment analysis techniques, primarily high performance liquid chromatography, or HPLC, to detect specific pigments as a time-saving alternative to individual algal cell identifications and counts. Remote sensing scientists are investigating the use of pigment signatures to construct pigment libraries analogous to mineral spectral libraries used in geological remote sensing applications. The accessory pigment approach has been used successfully in remote sensing using data from the Thematic Mapper, low-altitude, multiple channel scanners, field spectroradiometers and the AVIRIS hyperspectral scanner. Due to spectral and spatial resolution capabilities, AVIRIS is the sensor of choice for such

  12. Species composition and seasonal abundance of stink bugs (Hemiptera: Pentatomidae) in Louisiana soybean.

    PubMed

    Temple, J H; Davis, J A; Micinski, S; Hardke, J T; Price, P; Leonard, B R

    2013-08-01

    In Louisiana during the last decade, the redbanded stink bug, Piezodorus guildinii (Westwood), has become a significant and yield-limiting pest of soybean. The redbanded stink bug was previously reported in the United States in 1892, but was never considered an economically important pest until recently. Soybeans representing four maturity groups (MG) III, IV, V, and VI were sampled weekly from beginning bloom (R1) to physiological maturity (R8) during 2008-2010 at five locations across Louisiana to determine the Pentatomidae composition. In total, 13,146 stink bugs were captured and subsequently identified to species. The predominant species included the redbanded stink bug (54.2%); southern green stink bug (27.1%), Nezara viridula L.; brown stink bug (6.6%), Euschistus servus (Say); and green stink bug (5.5%), Acrosternum hilare (Say). Redbanded stink bug comprised the largest percentage of the complex collected at four of the five survey sites. Numbers exceeding action thresholds of this stink bug complex were only detected during R4 to R7 growth stages. Redbanded stink bug accounted for the largest percentage of the stink bug complex in early maturing soybean varieties (MG III [86%] and IV [60%]) and declined in later maturing soybeans (MG V [54%] and VI [50%]). The redbanded stink bug was initially identified in southern Louisiana during 2000 and had been reported in all soybean producing regions in Louisiana by 2006. This survey is the first to report the redbanded stink bug as a predominant pest of soybeans from locations within the United States. PMID:23905727

  13. Chemical Composition and Biological Activity of Essential Oils from Different Species of Piper from Panama.

    PubMed

    Santana, Ana I; Vila, Roser; Cañigueral, Salvador; Gupta, Mahabir P

    2016-07-01

    The chemical composition of leaf essential oils from 11 species of Piper from Panama was analyzed by a combination GC-FID and GC-MS procedures. Six of them had sesquiterpene hydrocarbons as major constituents, three were characterized by monoterpene hydrocarbons, one by a diterpene, and one by a phenylpropanoid, dillapiole. The main components identified in each species were: cembratrienol (25.4 %) in Piper augustum; β-pinene (26.6 %) in Piper corrugatum; α-pinene (19.4 %) in Piper curtispicum; trans-β-farnesene (63.7 %) in Piper darienense; p-cymene (43.9 %) in Piper grande; dillapiole (57.7 %) in Piper hispidum; linalool (14.5 %), α-phellandrene (13.8 %), and limonene (12.2 %) in Piper jacquemontianum; β-caryophyllene (45.2 %) in Piper longispicum; linalool (16.5 %), α-phellandrene (11.8 %), limonene (11.4 %), and p-cymene (9.0 %) in Piper multiplinervium; β-selinene (19.0 %), β-elemene (16.1 %), and α-selinene (15.5 %) in Piper reticulatum; and germacrene D (19.7 %) in Piper trigonum. The essential oils of P. hispidum and P. longispicum at a concentration of 250 µg/mL showed larvicidal activity against Aedes aegypti, while the oils from P. curtispicum, P. multiplinervium, P. reticulatum, and P. trigonum were inactive (LC100 ≥ 500 µg/mL). The essential oils of P. grande, P. jacquemontianum, and P. multiplinervium showed no significant antifungal activity (MIC > 250 µg/mL) against several yeasts and filamentous fungal strains. PMID:27286333

  14. REVIEW OF THE CURRENT STATUS OF MARINE ALGAL TOXICITY TESTING IN THE UNITED STATES

    EPA Science Inventory

    Algal toxicity testing is not new, but only within the past few years have data from such testing been used to help set standards for allowable contamination. arly toxicity testing with marine algae used a few planktonic species with inhibition of growth as the primary endpoint. ...

  15. Spectral modeling for the identification and quantification of algal blooms: A test of approach

    SciTech Connect

    Malthus, T.J.; Grieve, L.; Harwar, M.D.

    1997-06-01

    The aim of this paper is to develop and test a Monte Carlo modelling approach for the characterization of reflectance for different bloom-forming marine phytoplankton species. The model was tested on optical data for four species (Dunaliella salina, Pavlova pinguis, Emiliania huxleyi and Synechocystes spp.) and simulations performed over a range of chlorophyll concentrations. Discriminant analysis identified 10 key wavelengths which could be used to maximize the separation between the four species. The resulting wavelengths were combined in a neural network to show 100% accuracy in classifying species type. Further simulations were undertaken to investigate the effect of aquatic humus on reflectance characteristics and the change in wavelengths for algal discrimination. The implications for the development of algorithms for the identification of algal bloom species type by remote sensing are briefly discussed.

  16. Coral–algal phase shifts alter fish communities and reduce fisheries production

    PubMed Central

    Ainsworth, Cameron H; Mumby, Peter J

    2015-01-01

    Anthropogenic stress has been shown to reduce coral coverage in ecosystems all over the world. A phase shift towards an algae-dominated system may accompany coral loss. In this case, the composition of the reef-associated fish assemblage will change and human communities relying on reef fisheries for income and food security may be negatively impacted. We present a case study based on the Raja Ampat Archipelago in Eastern Indonesia. Using a dynamic food web model, we simulate the loss of coral reefs with accompanied transition towards an algae-dominated state and quantify the likely change in fish populations and fisheries productivity. One set of simulations represents extreme scenarios, including 100% loss of coral. In this experiment, ecosystem changes are driven by coral loss itself and a degree of habitat dependency by reef fish is assumed. An alternative simulation is presented without assumed habitat dependency, where changes to the ecosystem are driven by historical observations of reef fish communities when coral is lost. The coral–algal phase shift results in reduced biodiversity and ecosystem maturity. Relative increases in the biomass of small-bodied fish species mean higher productivity on reefs overall, but much reduced landings of traditionally targeted species. PMID:24953835

  17. Coral-algal phase shifts alter fish communities and reduce fisheries production.

    PubMed

    Ainsworth, Cameron H; Mumby, Peter J

    2015-01-01

    Anthropogenic stress has been shown to reduce coral coverage in ecosystems all over the world. A phase shift towards an algae-dominated system may accompany coral loss. In this case, the composition of the reef-associated fish assemblage will change and human communities relying on reef fisheries for income and food security may be negatively impacted. We present a case study based on the Raja Ampat Archipelago in Eastern Indonesia. Using a dynamic food web model, we simulate the loss of coral reefs with accompanied transition towards an algae-dominated state and quantify the likely change in fish populations and fisheries productivity. One set of simulations represents extreme scenarios, including 100% loss of coral. In this experiment, ecosystem changes are driven by coral loss itself and a degree of habitat dependency by reef fish is assumed. An alternative simulation is presented without assumed habitat dependency, where changes to the ecosystem are driven by historical observations of reef fish communities when coral is lost. The coral-algal phase shift results in reduced biodiversity and ecosystem maturity. Relative increases in the biomass of small-bodied fish species mean higher productivity on reefs overall, but much reduced landings of traditionally targeted species. PMID:24953835

  18. Harmful algal blooms: How strong is the evidence that nutrient ratios and forms influence their occurrence?

    NASA Astrophysics Data System (ADS)

    Davidson, Keith; Gowen, Richard J.; Tett, Paul; Bresnan, Eileen; Harrison, Paul J.; McKinney, April; Milligan, Stephen; Mills, David K.; Silke, Joe; Crooks, Anne-Marie

    2012-12-01

    There is a perception that anthropogenically-driven changes in nutrient supply to coastal waters influences the abundance, frequency and toxicity of harmful algal blooms (HABs) through a change in the form or ratio of nutrient that limits phytoplankton growth. If nutrient concentrations are not limiting for growth, then ratios do not influence floristic composition. At non-limiting concentrations, evidence that alteration of nitrogen: phosphorus (N:P) ratios has stimulated HABs is limited, and primarily based on hypothesised relationships in relatively few locations (in particular: Tolo Harbour Hong Kong and Dutch Coastal Waters). In all cases, an unequivocal causal link between an increase in HABs (frequency, magnitude or duration) and change in N or P as the limiting nutrient is difficult to establish. The silicon (Si) limitation hypothesis is generally supported by experimental evidence and field data on the nuisance flagellate Phaeocystis. We found little evidence that high N:Si ratios preferentially promote harmful dinoflagellates over benign species. Laboratory studies demonstrate that nutrient ratios can influence toxin production, but genus and species specific differences and environmental control make extrapolation of these data to the field difficult. Studies of the role of dissolved and particulate organic nutrients in the growth of HAB species, while limited, demonstrate the potential for organic nutrients (especially organic N) to support the growth of a range of HAB species. There is a clear need for better understanding of the role of mixotrophy in the formation of HABs and for studies of HAB and non-HAB species in competition for environmentally realistic concentrations of organic nutrients.

  19. Algal Supply System Design - Harmonized Version

    SciTech Connect

    Abodeely, Jared; Stevens, Daniel; Ray, Allison; Newby, Deborah; Schaller, Kastli

    2013-03-01

    The objective of this design report is to provide an assessment of current technologies used for production, dewatering, and converting microalgae cultivated in open-pond systems to biofuel. The original draft design was created in 2011 and has subsequently been brought into agreement with the DOE harmonized model. The design report extends beyond this harmonized model to discuss some of the challenges with assessing algal production systems, including the ability to (1) quickly assess alternative algal production system designs, (2) assess spatial and temporal variability, and (3) perform large-scale assessments considering multiple scenarios for thousands of potential sites. The Algae Logistics Model (ALM) was developed to address each of these limitations of current modeling efforts to enable assessment of the economic feasibility of algal production systems across the United States. The (ALM) enables (1) dynamic assessments using spatiotemporal conditions, (2) exploration of algal production system design configurations, (3) investigation of algal production system operating assumptions, and (4) trade-off assessments with technology decisions and operating assumptions. The report discusses results from the ALM, which is used to assess the baseline design determined by harmonization efforts between U.S. DOE national laboratories. Productivity and resource assessment data is provided by coupling the ALM with the Biomass Assessment Tool developed at PNNL. This high-fidelity data is dynamically passed to the ALM and used to help better understand the impacts of spatial and temporal constraints on algal production systems by providing a cost for producing extracted algal lipids annually for each potential site.

  20. Approaches for the detection of harmful algal blooms using oligonucleotide interactions.

    PubMed

    Bruce, Karen L; Leterme, Sophie C; Ellis, Amanda V; Lenehan, Claire E

    2015-01-01

    Blooms of microscopic algae in our waterways are becoming an increasingly important environmental concern. Many are sources of harmful biotoxins that can lead to death in humans, marine life and birds. Additionally, their biomass can cause damage to ecosystems such as oxygen depletion, displacement of species and habitat alteration. Globally, the number and frequency of harmful algal blooms has increased over the last few decades, and monitoring and detection strategies have become essential for managing these events. This review discusses developments in the use of oligonucleotide-based 'molecular probes' for the selective monitoring of algal cell numbers. Specifically, hybridisation techniques will be a focus. PMID:25381608

  1. EFFECTS OF FORAGE SPECIES ON FATTY ACID COMPOSITION OF BEEF LONGISSIMUS MUSCLE FROM FORAGE-FINISHED BEEF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forty-seven Angus-crossbred steers were used to evaluate the effects of forage species grazed in the last 41 d of the finishing period on rib composition, color, and palatability in forage-finished beef and compared to traditional high concentrate finished. Steers grazed naturalized pastures (bluegr...

  2. Nonlinear and threshold responses of grassland productivity and species composition to increased CO2 vary with soil type

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change is likely to cause non-linear responses in ecosystem function and threshold changes in species composition. Here we report aboveground net primary productivity (ANPP) responses to a continuous CO2 concentration gradient (250 to 500 µL L-1) in experimental grassland communities on...

  3. Nitrogen addition and harvest frequency rather than initial plant species composition determine vertical structure and light interception in grasslands.

    PubMed

    Petersen, Ute; Isselstein, Johannes

    2015-01-01

    In biodiversity experiments based on seeded experimental communities, species richness and species composition exert a strong influence on canopy structure and can lead to an improved use of aboveground resources. In this study, we want to explore whether these findings are applicable to agriculturally managed permanent grassland. Vertical layered profiles of biomass, leaf area (LA) and light intensity were measured in a removal-type biodiversity experiment (GrassMan) to compare the canopy structure in grassland vegetation of different plant species composition (called sward types). Additionally, the altered sward types were subjected to four different management regimes by a combination of the factors fertilization (unfertilized, NPK fertilized) and cutting frequency (one late cut or three cuts). In spite of large compositional differences (ratio grasses : non-leguminous forbs : leguminous forbs ranging from 93 : 7 : 0 to 39 : 52 : 9), the vegetation of the same management regime hardly differed in its canopy structure, whereas the different management regimes led to distinct vertical profiles in the vegetation. However, the allocation of biomass in response to cutting and fertilization differed among the sward types. Vegetation dominated by grasses was denser and had more LA when fertilized compared with vegetation rich in dicots which merely grew taller. In functionally more diverse vegetation, light interception was not increased compared with vegetation consisting of more than 90 % of grasses in terms of biomass. Management had a much stronger influence on structure and light interception than plant species composition in this grassland experiment. PMID:26199402

  4. Composition and toxigenic potential of the Fusarium graminearum species complex from maize ears, stalks and stubble in Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Detailed knowledge of the composition and toxigenic potential of the Fusarium graminearum species complex affecting maize crops in Brazil is lacking. A multilocus genotype approach was used to identify 539 isolates from three sub-collections: 1) maize kernels (n= 110) from five states spanning sout...

  5. Chemical composition of essential oils from four Vietnamese species of piper (piperaceae).

    PubMed

    Hieu, Le D; Thang, Tran D; Hoi, Tran M; Ogunwande, Isiaka A

    2014-01-01

    The chemical composition of essential oils from four Piper species, Piper retrofractum Vahl., P. boehmeriaefolium (Miq.) C. DC., P. sarmentosum Roxb., and P. maclurei Merr., were analysed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Nineteen to sixty-four compounds representing 92.0%-98.4% of the total contents were identified in the oil samples. The major constituents identified in P. retrofractum leaf oil were benzyl benzoate (14.4%), myrcene (14.4%), bicycloelemene (9.9%), bicyclogermacrene (7.0%) and β-caryophyllene (5.3%). On the other hand, the main constituents of P. boehmeriaefolium were α-copaene (28.3%), α-pinene (7.4%) and 1, 8-cineole (5.7%). P. sarmentosum showed a very different chemical profile characterized mainly by aromatic compounds and devoid of monoterpene hydrocarbons. The major constituents were benzyl benzoate (49.1%), benzyl alcohol (17.9%), 2-hydroxy-benzoic acid phenylmethyl ester (10.0%) and 2-butenyl-benzene (7.9%). The leaf of P. maclurei was characterized by higher amount of (E)-cinnamic acid (37.4%) and (E)-nerolidol (19.4%). Moreover, (Z)-9-octadecanoic acid methyl ester (28.0%), (E)-cinnamyl acetate (17.2%), phytol (12.2%) and (E)-cinnamaldehyde (8.8%) were the major compounds identified in the stem oil. PMID:24712088

  6. Comparative study of the chemical composition of essential oils of five Tagetes species collected in Venezuela.

    PubMed

    Armas, Kaylin; Rojas, Janne; Rojas, Luis; Morales, Antonio

    2012-09-01

    The leaves and inflorescences of five species of Tagetes, family Asteraceae, were collected from different locations in Mérida state, Venezuela, and their essential oils analyzed by GC and GC/MS. Several differences were observed in the composition of these oils, mainly regarding the major components, which for T. caracasana were trans-ocimenone (64.3%) and cis-tagetone (13.7%), and for T. erecta, piperitone (35.9%) and terpinolene (22.2%). High amounts of trans-anethole (87.5%) and estragole (10.7%) were observed in T. filifolia, while T. subulata essential oil contained terpinolene (26.0%), piperitenone (13.1%) and limonene (10.8%). For T. patula, two different oil samples were analyzed, leaves (TPL) and inflorescences (TPI). The TPL oil showed terpinolene (20.9%) and piperitenone (14.0%) as main components, while the TPI sample was composed mainly of beta-caryophyllene (23.7%), terpinolene (15.6%) and cis-beta-ocimene (15.5%). PMID:23074915

  7. Composition, antioxidant and antimicrobial activities of methanol extracts of some Acinos Miller species.

    PubMed

    Golubović, Tatjana; Palić, Radosav; Kitić, Dusanka; Stojanović, Gordana; Zlatković, Bojan; Ristić, Mihailo; Pavlović, Dragana

    2014-05-01

    GC and GC/MS analyses of the methanol extracts obtained from the aerial parts of six Acinos Miller species from Serbia and Montenegro were performed. Seventy-four constituents, accounting for 84.9-99.0% of the total composition of the extracts, were identified. The common feature of the A. suaveolens, A. majoranifolius and A. alpinus methanol extracts was the high content of monoterpenes, while the common feature of the A. graveolens, A. arvensis and A. hungaricus methanol extracts was the prevalence of sesquiterpenes. The total flavonoids, polyphenols and tannins content, as well as antioxidant activity (FRAP and DPPH assay) of the methanolic extracts were investigated. The highest antioxidant activity was observed in the extract of A. alpinus which had high levels of all polyphenol classes examined. A disk diffusion method was used for the evaluation of the antimicrobial activities of the extracts against a panel of microorganisms (bacteria: Bacillus subtilis, Clostridium pyogenes, Enterococcus sp., Micrococcus flavus, Sarcina lutea, Staphylococcus aureus, Klebsiella pneumoniae, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella enteritidis and Escherichia coli; fungi: Aspergillus niger, Candida albicans and Saccharomyces cerevisiae). The preliminary bioassay results indicated that the methanol extract of A. alpinus could be a possible source of antioxidant and antimicrobial compounds. PMID:25026735

  8. Thermal stability and microstructure of catalytic alumina composite support with lanthanum species

    NASA Astrophysics Data System (ADS)

    Ozawa, Masakuni; Nishio, Yoshitoyo

    2016-09-01

    Lanthanum (La) modified γ-alumina composite was examined for application toward thermostable catalytic support at elevated temperature. La added alumina was prepared through an aqueous process using lanthanum (III) nitrate and then characterized by surface area measurement, X-ray powder diffraction (XRD), differential thermal analysis (DTA), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoemission spectroscopy (XPS) and surface desorption of CO2. It was found that the properties depended on the La content and heat treatment temperatures. The characterization of the surface, structural and chemical properties of La-Al2O3 showed the existence of a strong interaction between the La species and alumina via formation of new phase and modified surface in Al2O3 samples. LaAlO3 nanoparticle formed among alumina particles by the solid phase reaction of Al2O3 and La2O3. The increase of the surface basicity of La modified alumina was demonstrated using CO2 temperature programmed desorption experiments. The controlled surface interaction between La oxide and alumina provide the unique surface and structural properties of the resulting mixed oxides as catalysts and catalytic supports.

  9. Patterns in Species Composition of Fish and Selected Invertebrate Assemblages in Estuarine Subregions near Ponce de Leon Inlet, Florida

    NASA Astrophysics Data System (ADS)

    Paperno, R.; Mille, K. J.; Kadison, E.

    2001-01-01

    The Florida Fish and Wildlife Conservation Commission's Fisheries-Independent Monitoring program monitored the species composition and relative abundance of fishes and selected invertebrates in the estuarine waters near Ponce de Leon Inlet, Florida, from January 1993 through to December 1996. Sampling sites were located in three distinct physiographic and biotic estuarine subregions: Mosquito Lagoon (ML; 11 stations), Ponce de Leon Inlet (PI; 8 stations), and Tomoka Basin/River (TR; 8 stations). This series of subregions associated with Ponce de Leon Inlet is a species-rich estuarine system that is numerically dominated by a few taxa. A total of 1 080 477 animals representing 160 species and 56 families were recorded. Anchoa spp. (29·9%) and Menidia spp. (12·6%) were the numerically dominant taxa. Sciaenidae and Gobiidae were the most speciose families, with 12 species each (14·0% and 1·7% of the total animals collected, respectively), followed by the bothids 10 species (0·6% of total animals). Detrended correspondence analysis showed that the subregions could be discriminated by their respective species composition and relative abundance. Spatial differences in species composition were principally attributed to differences in the magnitude of seasonal recruitment events and to habitat characteristics associated with the presence of seagrass, inlet dynamics, or the influence of freshwater discharge. The presence of freshwater taxa (centrarchids) and the seasonal recruitment of juvenile Penaeidae, Micropogonias undulatus , Stellifer lanceolatus and Leiostomus xanthurus, characterize the TR area, whereas the presence of species associated with higher salinities ( Opisthonema oglinum and Harengula jaguana) characterize PI and with seagrass ( Lucania parva and Lagodon rhomboides) characterize ML.

  10. Algal Energy Conversion and Capture

    NASA Astrophysics Data System (ADS)

    Hazendonk, P.

    2015-12-01

    We address the potential for energy conversions and capture for: energy generation; reduction in energy use; reduction in greenhouse gas emissions; remediation of water and air pollution; protection and enhancement of soil fertility. These processes have the potential to sequester carbon at scales that may have global impact. Energy conversion and capture strategies evaluate energy use and production from agriculture, urban areas and industries, and apply existing and emerging technologies to reduce and recapture energy embedded in waste products. The basis of biocrude production from Micro-algal feedstocks: 1) The nutrients from the liquid fraction of waste streams are concentrated and fed into photo bioreactors (essentially large vessels in which microalgae are grown) along with CO2 from flue gasses from down stream processes. 2) The algae are processed to remove high value products such as proteins and beta-carotenes. The advantage of algae feedstocks is the high biomass productivity is 30-50 times that of land based crops and the remaining biomass contains minimal components that are difficult to convert to biocrude. 3) The remaining biomass undergoes hydrothermal liquefaction to produces biocrude and biochar. The flue gasses of this process can be used to produce electricity (fuel cell) and subsequently fed back into the photobioreactor. The thermal energy required for this process is small, hence readily obtained from solar-thermal sources, and furthermore no drying or preprocessing is required keeping the energy overhead extremely small. 4) The biocrude can be upgraded and refined as conventional crude oil, creating a range of liquid fuels. In principle this process can be applied on the farm scale to the municipal scale. Overall, our primary food production is too dependent on fossil fuels. Energy conversion and capture can make food production sustainable.

  11. SPECIES COMPOSITION, DISTRIBUTION, LIFE FORMS AND FOLK NOMENCLATURE OF FOREST AND COMMON LAND PLANTS OF WESTERN CHITWAN, NEPAL

    PubMed Central

    Dangol, D. R.

    2012-01-01

    This paper enumerates 349 plant species belonging to 77 families of vascular plants collected in the winter seasons of 1996 and 2000 by the flora teams of the Population and Ecology Research Laboratory, Nepal. Of the total species, 249 species belong to dicotyledons, 87 species to monocotyledons and 13 species to pteridophytes. Among the families, dicotyledons contributed the highest number of families (55 in number) followed by monocotyledons and pteridophytes. In the study areas, species composition varies with the type of habitats in the study plots. Some species are unique in distribution. The highest unique species are contributed by common lands (87 spp.), followed by the Chitwan National Park forest (36 spp.) and Tikauli forest (32 spp.). Ageratum houstonianum Mill., Cynodon dactylon (L.) Pers., Imperata cylindrica (L.) Beauv., Rungia parviflora (Retz.) Nees, Saccharum spontaneum L. and Thelypteris auriculata (J. Sm.) K. Iwats are the most common species across all the research blocks. Of the listed plants, many plants have local names either in Nepalese or other tribal languages. Plants are named in different ways on the basis of habit, habitat, smell, taste, and morphological characters of the plants, which are also the basis of nomenclature in plant taxonomy. PMID:22962539

  12. SPECIES COMPOSITION, DISTRIBUTION, LIFE FORMS AND FOLK NOMENCLATURE OF FOREST AND COMMON LAND PLANTS OF WESTERN CHITWAN, NEPAL.

    PubMed

    Dangol, D R

    2005-01-01

    This paper enumerates 349 plant species belonging to 77 families of vascular plants collected in the winter seasons of 1996 and 2000 by the flora teams of the Population and Ecology Research Laboratory, Nepal. Of the total species, 249 species belong to dicotyledons, 87 species to monocotyledons and 13 species to pteridophytes. Among the families, dicotyledons contributed the highest number of families (55 in number) followed by monocotyledons and pteridophytes. In the study areas, species composition varies with the type of habitats in the study plots. Some species are unique in distribution. The highest unique species are contributed by common lands (87 spp.), followed by the Chitwan National Park forest (36 spp.) and Tikauli forest (32 spp.). Ageratum houstonianum Mill., Cynodon dactylon (L.) Pers., Imperata cylindrica (L.) Beauv., Rungia parviflora (Retz.) Nees, Saccharum spontaneum L. and Thelypteris auriculata (J. Sm.) K. Iwats are the most common species across all the research blocks. Of the listed plants, many plants have local names either in Nepalese or other tribal languages. Plants are named in different ways on the basis of habit, habitat, smell, taste, and morphological characters of the plants, which are also the basis of nomenclature in plant taxonomy. PMID:22962539

  13. Compositional changes in (iso)flavonoids and estrogenic activity of three edible Lupinus species by germination and Rhizopus-elicitation.

    PubMed

    Aisyah, Siti; Vincken, Jean-Paul; Andini, Silvia; Mardiah, Zahara; Gruppen, Harry

    2016-02-01

    The effects of germination and elicitation on (iso)flavonoid composition of extracts from three edible lupine species (Lupinus luteus, Lupinus albus, Lupinus angustifolius) were determined by RP-UHPLC-MS(n). The total (iso)flavonoid content of lupine increased over 10-fold upon germination, with the total content and composition of isoflavonoids more affected than those of flavonoids. Glycosylated isoflavones were the most predominant compounds found in lupine seedlings. Lesser amounts of isoflavone aglycones, including prenylated ones, were also accumulated. Elicitation with Rhizopus oryzae, in addition to germination, raised the content of isoflavonoids further: the total content of 2'-hydroxygenistein derivatives was increased considerably, without increasing that of genistein derivatives. Elicitation by fungus triggered prenylation of isoflavonoids, especially of the 2'-hydroxygenistein derivatives. The preferred positions of prenylation differed among the three lupine species. The change in isoflavone composition increased the agonistic activity of the extracts towards the human estrogen receptors, whereas no antagonistic activity was observed. PMID:26749476

  14. SPECIES COMPOSITION AND DIVERSITY AS REGULATORS OF TEMPORAL VARIABILITY IN BIOMASS PRODUCTION OF TALLGRASS PRAIRIE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species diversity is thought to stabilize functioning of plant communities, although diversity-stability studies have focused on species richness to the neglect of the second component of diversity, species evenness (equitability with which biomass or abundances are distributed among species). An a...

  15. Changes in relative species compositions of biting midges (Diptera: Ceratopogonidae) and an outbreak of Oropouche virus in Iquitos, Peru.

    PubMed

    Mercer, David R; Castillo-Pizango, Maikol J

    2005-07-01

    Species compositions of Culicoides paraensis (Goeldi) (Diptera: Ceratopogonidae), the major vector of Oropouche virus to humans in Central and South American urban cycles, and Culicoides insinuatus Ortiz & Leon differed along a northeast-to-southwest transect across Iquitos, Department of Loreto, Peru. The relative distributions of the species were consistent with patterns of human outbreaks along the Amazon River. We resumed collection of biting midges between May 2000 and January 2004 at three sites previously sampled (1996 -1997) to determine whether the known vector was expanding its range relative to the earlier survey. C. paraensis did not replace C. insinuatus across the region surveyed. Instead, C. insinuatus dominated the more southern sites and significantly increased its relative proportion at all three sites. Apparently, microhabitat differences and not range expansion by C. paraensis were responsible for differences in species compositions across the sample sites. PMID:16119543

  16. Effects of environmental stresses on the species composition of phytoplankton populations. Final report, 1 March 1979-15 July 1980

    SciTech Connect

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

    1980-07-01

    Studies concerned with the impact of anthropogenic stress associated with coastally located power plants on the species composition of marine phytoplankton assemblages have been underway under this Contract for 24 months. The impact of three pollutants associated with power plant cooling water systems has been studied: copper, chlorine, and thermal elevation. The primary goal has been to determine whether chronic addition of these pollutants at sublethal levels can affect the species composition and the succession of dominant species in natural phytoplankton assemblages. Stresses have been studied both singly and in combination. In conjunction with these primary objectives, a number of related problems imvolving phytoplankton response to pollutants and to zooplankton grazing have been studied. These experiments have been performed both in the large volume enclosures outdoors, and in laboratory cultures under constant conditions.

  17. Non-conventional approaches to food processing in CELSS. I-algal proteins; characterization and process optimization

    NASA Astrophysics Data System (ADS)

    Nakhost, Z.; Karel, M.; Krukonis, V. J.

    Protein isolate obtained from green algae (Scenedesmus obliquus) cultivated under controlled conditions was characterized. Molecular weight determination of fractionated algal proteins using SDS-polyacrylamide gel electrophoresis revealed a wide spectrum of molecular weights ranging from 15,000 to 220,000. Isoelectric points of dissociated proteins were in the range of 3.95 to 6.20. Amino acid composition of protein isolate compared favorably with FAO standards. High content of essential amino acids leucine, valine, phenylalanine and lysine makes algal protein isolate a high quality component of CELSS diets. To optimize the removal of algal lipids and pigments supercritical carbon dioxide extraction (with and without ethanol as a co-solvent) was used. Addition of ethanol to supercritical CO2 resulted in more efficient removal of algal lipids and produced protein isolate with a good yield and protein recovery. The protein isolate extracted by the above mixture had an improved water solubility.

  18. Algal layer ratios as indicators of air pollutant effects in Permelia sulcata

    USGS Publications Warehouse

    Bennett, J.P.

    2002-01-01

    Parmelia sulcata Taylor is generally believed to be fairly pollution tolerant, and consequently it is sometimes collected in urban and/or polluted localities. The condition of these specimens, however, is not always luxuriant and healthy. This study tested the hypothesis that total thallus and algal layer thickness, and the algal layer ratio would be thinner in polluted areas, thus allowing these characters to be used a indicators of air pollutant effects. Herbarium specimens were studied from 16 different localities varying in pollution level. The thallus and algal layers and ratio were not affected by year or locality of sampling, but decreased 11, 31 and 21% respectively between low and high pollution level localities. These results agreed with earlier studies using other species, but further work is needed to clarify the effects of geography and substrate on these phenomena.

  19. Simulated Macro-Algal Outbreak Triggers a Large-Scale Response on Coral Reefs.

    PubMed

    Welsh, Justin Q; Bellwood, David R

    2015-01-01

    Ecosystem degradation has become common throughout the world. On coral reefs, macroalgal outbreaks are one of the most widely documented signs of degradation. This study simulated local-scale degradation on a healthy coral reef to determine how resident taxa, with the potential to reverse algal outbreaks, respond. We utilized a combination of acoustic and video monitoring to quantify changes in the movements and densities, respectively, of coral reef herbivores following a simulated algal outbreak. We found an unprecedented accumulation of functionally important herbivorous taxa in response to algal increases. Herbivore densities increased by 267% where algae were present. The increase in herbivore densities was driven primarily by an accumulation of the browsing taxa Naso unicornis and Kyphosus vaigiensis, two species which are known to be important in removing macroalgae and which may be capable of reversing algal outbreaks. However, resident individuals at the site of algal increase exhibited no change in their movements. Instead, analysis of the size classes of the responding individuals indicates that large functionally-important non-resident individuals changed their movement patterns to move in and feed on the algae. This suggests that local-scale reef processes may not be sufficient to mitigate the effects of local degradation and highlights the importance of mobile links and cross-scale interactions. PMID:26171788

  20. Simulated Macro-Algal Outbreak Triggers a Large-Scale Response on Coral Reefs

    PubMed Central

    Welsh, Justin Q.; Bellwood, David R.

    2015-01-01

    Ecosystem degradation has become common throughout the world. On coral reefs, macroalgal outbreaks are one of the most widely documented signs of degradation. This study simulated local-scale degradation on a healthy coral reef to determine how resident taxa, with the potential to reverse algal outbreaks, respond. We utilized a combination of acoustic and video monitoring to quantify changes in the movements and densities, respectively, of coral reef herbivores following a simulated algal outbreak. We found an unprecedented accumulation of functionally important herbivorous taxa in response to algal increases. Herbivore densities increased by 267% where algae were present. The increase in herbivore densities was driven primarily by an accumulation of the browsing taxa Naso unicornis and Kyphosus vaigiensis, two species which are known to be important in removing macroalgae and which may be capable of reversing algal outbreaks. However, resident individuals at the site of algal increase exhibited no change in their movements. Instead, analysis of the size classes of the responding individuals indicates that large functionally-important non-resident individuals changed their movement patterns to move in and feed on the algae. This suggests that local-scale reef processes may not be sufficient to mitigate the effects of local degradation and highlights the importance of mobile links and cross-scale interactions. PMID:26171788

  1. Boreal Forest Ecosystems Along Canadian Transect in Central Canada:Multivariate Analysis of Species Composition, Detritus and Soil Carbon Data

    NASA Astrophysics Data System (ADS)

    Bhatti, J.; Yu, Z.; Apps, M. J.

    2001-05-01

    The species composition, detritus, and soil data from 97 boreal forest stands along a transect (BFTCS) in central Canada were analyzed using (detrended) (canonical) correspondence analysis to determine the dominant environmental/site variables that differentiate these forest stands. The forests include aspen, jack pine, black spruce and mixed wood stands. Black spruce stands are densely clustered together on understory DCA plot, suggesting that they have consistent understory species composition, such as feathermoss and ericades, whereas aspen stands have most diverse understory species composition (~30 species), mostly shrubs and herbs. Jack pine stands have several characteristic species of reindeer lichens (Cladina spp.), but have rare saplings and seedlings of jack pine. Although climatic variables show large variation along the transect, the CCA results indicate that site conditions are more important in determining species composition and differentiating the stand types. Characteristics of forest floor (duff layer, woody debris, and drainage) appear to be among the most important site variables. The black spruce stands have significantly higher average carbon (C) densities in duff layer (43,530 kg C/ha) than aspen (25,500 kg C/ha) and jack pine stands (19,400 kg C/ha). The thick duff layer in lowland black spruce stands plays an important role in regulating soil temperatures and moistures, and organic-matter decomposition, which in turn affect the ecosystem C dynamics. During forest succession after a stand-replacing disturbance (e.g., fires), tree biomass increases in all stand types as forests recover; however, detritus biomass first decreases and then increases after ~80 years. In all stand types, duff layer thickness increases with stand regrowth ages. Soil C densities show slight decrease with ages in aspen stands, but increase in other stand types. These results indicate the complex C transfer processes among different components (tree biomass, detritus

  2. Platy algal banks: Modern and ancient

    SciTech Connect

    Brinton, L. )

    1990-05-01

    Plaly algal banks and associated cycles in the lower Ismay zone of the Paradox Formation are exposed along the walls of the San Juan River canyon, southeastern Utah. These complexes closely resemble algal bank reservoirs in the lower Ismay zone of Ismay and Cache, and possibly other Paradox basin fields. Similarities include facies relationships, lateral and vertical textural variations, and early diagenesis. Extensive algal banks exposed along the San Juan canyon generally have flat bases and mound and swale topographic surfaces, and are separated by interbank channels. The surficial mounds have a regular amplitude and wavelength suggesting a hydrologic rather than biologic influence on topography. The banks themselves, however, are believed to be thick, predominantly in-situ accumulations of platy algae. Distribution of algal banks can be mapped on a field scale; mound and swale topographic features may be identified in core on the basis of depositional and early diagenetic characteristics. Halimeda bioherms (Holocene) cover large areas behind the Great Barrier Reef, developing adjacent to the deep passes that separate the individual reefs. These large in-situ accumulations (20-50 m deep) display similar bank geometries, interbank features, topographic features, vertical textural sequence (including porosity type and distribution), and facies relationships to algal banks observed in the outcropping and subsurface Paradox Formation. Although the hydrodynamic and paleobathymetric settings differ markedly between these two examples, analogies between the mounds themselves are very close. The resemblance lends relevance to exploration and development drilling.

  3. Pyrolysis Strategies for Effective Utilization of Lignocellulosic and Algal Biomass

    NASA Astrophysics Data System (ADS)

    Maddi, Balakrishna

    Pyrolysis is a processing technique involving thermal degradation of biomass in the absence of oxygen. The bio-oils obtained following the condensation of the pyrolysis vapors form a convenient starting point for valorizing the major components of lignocellulosic as well as algal biomass feed stocks for the production of fuels and value-added chemicals. Pyrolysis can be implemented on whole biomass or on residues left behind following standard fractionation methods. Microalgae and oil seeds predominantly consist of protein, carbohydrate and triglycerides, whereas lignocellulose is composed of carbohydrates (cellulose and hemicellulose) and lignin. The differences in the major components of these two types of biomass will necessitate different pyrolysis strategies to derive the optimal benefits from the resulting bio-oils. In this thesis, novel pyrolysis strategies were developed that enable efficient utilization of the bio-oils (and/or their vapors) from lignocellulose, algae, as well as oil seed feed stocks. With lignocellulosic feed stocks, pyrolysis of whole biomass as well as the lignin residue left behind following well-established pretreatment and saccharification (i.e., depolymerization of cellulose and hemicellulose to their monomeric-sugars) of the biomass was studied with and without catalysts. Following this, pyrolysis of (lipid-deficient) algae and lignocellulosic feed stocks, under similar reactor conditions, was performed for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from

  4. Composition and hydrothermal pretreatment and enzymatic saccharification performance of grasses and legumes from a mixed-species prairie

    PubMed Central

    2011-01-01

    Background Mixtures of prairie species (mixed prairie species; MPS) have been proposed to offer important advantages as a feedstock for sustainable production of fuels and chemicals. Therefore, understanding the performance in hydrothermal pretreatment and enzymatic hydrolysis of select species harvested from a mixed prairie is valuable in selecting these components for such applications. This study examined composition and sugar release from the most abundant components of a plot of MPS: a C3 grass (Poa pratensis), a C4 grass (Schizachyrium scoparium), and a legume (Lupinus perennis). Results from this study provide a platform to evaluate differences between grass and leguminous species, and the factors controlling their recalcitrance to pretreatment and enzymatic hydrolysis. Results Significant differences were found between the grass and leguminous species, and between the individual anatomical components that influence the recalcitrance of MPS. We found that both grasses contained higher levels of sugars than did the legume, and also exhibited higher sugar yields as a percentage of the maximum possible from combined pretreatment and enzymatic hydrolysis. Furthermore, particle size, acid-insoluble residue (AcIR), and xylose removal were not found to have a direct significant effect on glucan digestibility for any of the species tested, whereas anatomical composition was a key factor in both grass and legume recalcitrance, with the stems consistently exhibiting higher recalcitrance than the other anatomical fractions. Conclusions The prairie species tested in this study responded well to hydrothermal pretreatment and enzymatic saccharification. Information from this study supports recommendations as to which plant types and species are more desirable for biological conversion in a mixture of prairie species, in addition to identifying fractions of the plants that would most benefit from genetic modification or targeted growth. PMID:22085451

  5. The Hawaiian Freshwater Algal Database (HfwADB): a laboratory LIMS and online biodiversity resource

    PubMed Central

    2012-01-01

    Background Biodiversity databases serve the important role of highlighting species-level diversity from defined geographical regions. Databases that are specially designed to accommodate the types of data gathered during regional surveys are valuable in allowing full data access and display to researchers not directly involved with the project, while serving as a Laboratory Information Management System (LIMS). The Hawaiian Freshwater Algal Database, or HfwADB, was modified from the Hawaiian Algal Database to showcase non-marine algal specimens collected from the Hawaiian Archipelago by accommodating the additional level of organization required for samples including multiple species. Description The Hawaiian Freshwater Algal Database is a comprehensive and searchable database containing photographs and micrographs of samples and collection sites, geo-referenced collecting information, taxonomic data and standardized DNA sequence data. All data for individual samples are linked through unique 10-digit accession numbers (“Isolate Accession”), the first five of which correspond to the collection site (“Environmental Accession”). Users can search online for sample information by accession number, various levels of taxonomy, habitat or collection site. HfwADB is hosted at the University of Hawaii, and was made publicly accessible in October 2011. At the present time the database houses data for over 2,825 samples of non-marine algae from 1,786 collection sites from the Hawaiian Archipelago. These samples include cyanobacteria, red and green algae and diatoms, as well as lesser representation from some other algal lineages. Conclusions HfwADB is a digital repository that acts as a Laboratory Information Management System for Hawaiian non-marine algal data. Users can interact with the repository through the web to view relevant habitat data (including geo-referenced collection locations) and download images of collection sites, specimen photographs and

  6. Divergent composition but similar function of soil food webs of individual plants: plant species and community effects.

    PubMed

    Bezemer, T M; Fountain, M T; Barea, J M; Christensen, S; Dekker, S C; Duyts, H; van Hal, R; Harvey, J A; Hedlund, K; Maraun, M; Mikola, J; Mladenov, A G; Robin, C; de Ruiter, P C; Scheu, S; Setälä, H; Smilauer, P; van der Putten, W H

    2010-10-01

    Soils are extremely rich in biodiversity, and soil organisms play pivotal roles in supporting terrestrial life, but the role that individual plants and plant communities play in influencing the diversity and functioning of soil food webs remains highly debated. Plants, as primary producers and providers of resources to the soil food web, are of vital importance for the composition, structure, and functioning of soil communities. However, whether natural soil food webs that are completely open to immigration and emigration differ underneath individual plants remains unknown. In a biodiversity restoration experiment we first compared the soil nematode communities of 228 individual plants belonging to eight herbaceous species. We included grass, leguminous, and non-leguminous species. Each individual plant grew intermingled with other species, but all plant species had a different nematode community. Moreover, nematode communities were more similar when plant individuals were growing in the same as compared to different plant communities, and these effects were most apparent for the groups of bacterivorous, carnivorous, and omnivorous nematodes. Subsequently, we analyzed the composition, structure, and functioning of the complete soil food webs of 58 individual plants, belonging to two of the plant species, Lotus corniculatus (Fabaceae) and Plantago lanceolata (Plantaginaceae). We isolated and identified more than 150 taxa/groups of soil organisms. The soil community composition and structure of the entire food webs were influenced both by the species identity of the plant individual and the surrounding plant community. Unexpectedly, plant identity had the strongest effects on decomposing soil organisms, widely believed to be generalist feeders. In contrast, quantitative food web modeling showed that the composition of the plant community influenced nitrogen mineralization under individual plants, but that plant species identity did not affect nitrogen or carbon

  7. Critical evaluation and modeling of algal harvesting using dissolved air flotation. DAF Algal Harvesting Modeling

    DOE PAGESBeta

    Zhang, Xuezhi; Hewson, John C.; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2014-07-14

    In our study, Chlorella zofingiensis harvesting by dissolved air flotation (DAF) was critically evaluated with regard to algal concentration, culture conditions, type and dosage of coagulants, and recycle ratio. Harvesting efficiency increased with coagulant dosage and leveled off at 81%, 86%, 91%, and 87% when chitosan, Al3+, Fe3+, and cetyl trimethylammonium bromide (CTAB) were used at dosages of 70, 180, 250, and 500 mg g-1, respectively. The DAF efficiency-coagulant dosage relationship changed with algal culture conditions. In evaluating the influence of the initial algal concentration and recycle ratio revealed that, under conditions typical for algal harvesting, we found that itmore » is possible that the number of bubbles is insufficient. A DAF algal harvesting model was developed to explain this observation by introducing mass-based floc size distributions and a bubble limitation into the white water blanket model. Moreover, the model revealed the importance of coagulation to increase floc-bubble collision and attachment, and the preferential interaction of bubbles with larger flocs, which limited the availability of bubbles to the smaller sized flocs. The harvesting efficiencies predicted by the model agree reasonably with experimental data obtained at different Al3+ dosages,