WorldWideScience

Sample records for marine microalgal communities

  1. Toxicity of the pharmaceutical clotrimazole to marine microalgal communities

    International Nuclear Information System (INIS)

    Porsbring, Tobias; Blanck, Hans; Tjellstroem, Henrik; Backhaus, Thomas

    2009-01-01

    Clotrimazole belongs to the group of 14α-demethylase inhibiting fungicides. It is widely used in human and veterinary medicine and has been identified as a priority pollutant for the marine environment. However, the toxicity of clotrimazole to marine primary producers is largely unknown. We therefore sampled natural microalgal communities (periphyton) and exposed them to concentration series of clotrimazole over 4 days. 50 pmol/L clotrimazole caused a concentration-dependent accumulation of C14α-methylated sterol precursors, which coincided with a decrease in algal-specific C14-desmethyl sterols. This indicates an inhibition of algal 14α-demethylases already at environmental concentrations. A clotrimazole concentration of 500 pmol/L reduced total sterol content to 64% of control level. Community chlorophyll a content was affected by clotrimazole in a bi-phasic manner with first reductions becoming visible at 500 pmol/L, along with indications of an altered cycling of photoprotective xanthophyll pigments. Concentrations of 10-100 nmol/L and higher caused large reductions in community growth, and changed community pigment profiles in a concentration-dependent monotonous manner. The study further indicated that diatoms use obtusifoliol as a natural substrate for 14α-demethylase, just as higher plants do but also utilize norlanosterol

  2. Regulations for marine microalgal toxins: Towards harmonization of ...

    African Journals Online (AJOL)

    The World Trade Organization and the General Agreements on Tariffs and Trade encourage the harmonization of regulations on food safety requirements. The current policy on trade liberalization of seafood is presented, together with a review of the regulations for marine microalgal toxins. Activities on harmonization of ...

  3. Studies on the effects on growth and antioxidant responses of two marine microalgal species to uniconazole

    Science.gov (United States)

    Mei, Xueqiao; Zheng, Kang; Wang, Lingdong; Li, Yantuan

    2014-10-01

    Uniconazole, as a plant growth retardant, can enhance stress tolerance in plants, possibly because of improved antioxidation defense mechanisms with higher activities of superoxide dismutase (SOD) and peroxidase (POD) enzymes that retard lipid peroxidation and membrane deterioration. These years much attention has been focused on the responses of antioxidant system in plants to uniconazole stress, but such studies on aquatic organism are very few. Moreover, no information is available on growth and antioxidant response in marine microalgae to uniconazole. In this paper, the growth and antioxidant responses of two marine microalgal species, Platymonas helgolandica and Pavlova viridis, at six uniconazole concentrations (0-15 mg L-1) were investigated. The results demonstrated that 3 mg L-1 uniconazole could increase significantly chlorophyll a and carbohydrate contents of P. helgolandica ( P enzymes, superoxide dismutase (SOD) and catalase (CAT) were enhanced remarkably at low concentrations of uniconazole. However, significant reduction of SOD and CAT activities was observed at higher concentrations of uniconazole.

  4. A trait based dynamic energy budget approach to explore emergent microalgal community structure

    Science.gov (United States)

    Cheng, Y.; Bouskill, N.; Karaoz, U.; Geng, H.; Lane, T.; Pett-Ridge, J.; Mayali, X.; Brodie, E.

    2015-12-01

    Microalgae play important roles in the global carbon budget. Phytoplankton, including microalgae, are responsible for around 50% of global primary production, and also hold promise as a viable renewable biofuel source. Research has been underway for decades to realize the full potential of algal biofuels at the commercial scale, however, uni-algal ponds are typically threatened by collapse due to microalgal grazing and parasite invasions. Recently, it has been proposed that functionally diverse microalgal-bacterial communities can achieve high biomass and/or lipid yields, and are more stable (less susceptible to invasion) than a monoculture. Similar positive diversity-productivity relationships have been observed in a wide range of ecosystem studies, but the purposeful maintenance of a diverse microbiome is less common in managed systems. In our work, a trait based dynamic energy budget model was developed to explore emergent microalgal community structure under various environmental (e.g. light, temperature, nutrient availability) conditions. The complex algal community can be reduced into functional groups (guilds). Each guild (algae or bacteria) is characterized by distinct physiological traits (e.g. nutrient requirement, growth rate, substrate affinity, lipid production) constrained by biochemical trade-offs. These trait values are derived from literature and information encoded in genomic data. Metabolism of the algae and the bacterial species (symbiotic or non-symbiotic) are described within a dynamic energy budget framework. The model offers a mechanistic framework to predict the optimal microalgal community assemblage towards high productivity and resistance to invasion under prevailing environmental conditions.

  5. Controls on microalgal community structures in cryoconite holes upon high-Arctic glaciers, Svalbard

    Czech Academy of Sciences Publication Activity Database

    Vonnahme, T.R.; Devetter, Miloslav; Žárský, J.D.; Šabacká, M.; Elster, Josef

    2016-01-01

    Roč. 13, č. 3 (2016), s. 659-674 ISSN 1726-4170 Institutional support: RVO:60077344 ; RVO:67985939 Keywords : microalgal communities * cryoconite holes * high-Arctic glaciers * Svalbard Subject RIV: EH - Ecology, Behaviour Impact factor: 3.851, year: 2016

  6. On microalgal settlements and the sluggish development of marine biofouling in Port Blair waters, Andamans.

    Science.gov (United States)

    Eashwar, M; Nallathambi, T; Kuberaraj, K

    2008-01-01

    Settlement of microalgae was investigated on Perspex, aluminium and zinc coupons immersed in Port Blair Bay waters for over 3 months. Commencement of fouling was exceptionally slow, and few microalgae were found until 14 days. Settlement occurred thereafter, and 47 microalgal species contributed to the fouling. The dominant forms belonged to the genera Navicula and Nitzschia, whereas Coscinodiscus eccentricus, Gyrosigma balticum and Trichodesmium erythraeum also accounted for high proportions of the settlements. The dominance of Nitzschia sigma was particularly marked on zinc coupons, suggesting an ability by the organism to resist toxicity. Settlement of both centric and pennate diatoms was observed in the early and mid periods, and absolute dominance of the pennate diatoms subsequently. The fouling mass was low even after 103 days, and it is speculated that strong ultraviolet radiation might be the prime reason for the sluggish development of marine biofouling in these oceanic island waters.

  7. Microalgal cultivation and utilization in sustainable energy production

    Energy Technology Data Exchange (ETDEWEB)

    Lakaniemi, A.-M.

    2012-07-01

    Microalgae are a promising feedstock for biofuel and bioenergy production due to their high photosynthetic efficiencies, high growth rates and no need for external organic carbon supply. However, microalgal biomass cultivation for energy production purposes is still rare in commercial scale. Further research and development is needed to make microalgal derived energy sustainable and economically competitive. This work investigated cultivation of fresh water microalga Chlorella vulgaris and marine microalga Dunaliella tertiolecta and their utilization in production of hydrogen, methane, electricity, butanol and bio-oil after bulk harvesting the biomass. Growth of the two microalgae was studied in five different photobioreactor (PBR) configurations especially concentrating on the quantification and characterization of heterotrophic bacteria in non-axenic microalgal cultivations and microalgal utilization of different nitrogen sources. Anaerobic cultures used for the energy conversion processes were enriched from a mesophilic municipal sewage digester separately for production of H{sub 2}, CH{sub 4} and electricity from the two microalgal species. After culture enrichment, energy conversion yields of microalgal biomass to the different energy carriers were compared. In summary, this study demonstrated that both C. vulgaris and D. tertiolecta can be used for production of Hv(2), CHv(4), electricity, butanol and lipids. Based on this study C. vulgaris is more suitable for bioenergy production than D. tertiolecta. Depending on cellular lipid content, lipid utilization for bio-oil production and anaerobic digestion were the most potent means of converting C. vulgaris biomass to energy. The study also revealed diverse microbial communities in non-axenic microalgal photobioreactor cultures and in anaerobic consortia converting microalgal biomass to energy carriers

  8. Use of Cellulolytic Marine Bacteria for Enzymatic Pretreatment in Microalgal Biogas Production

    Science.gov (United States)

    Muñoz, Camilo; Hidalgo, Catalina; Zapata, Manuel; Jeison, David; Riquelme, Carlos

    2014-01-01

    In this study, we designed and evaluated a microalgal pretreatment method using cellulolytic bacteria that naturally degrades microalgae in their native habitat. Bacterial strains were isolated from each of two mollusk species in a medium containing 1% carboxymethyl cellulose agar. We selected nine bacterial strains that had endoglucanase activity: five strains from Mytilus chilensis, a Chilean mussel, and four strains from Mesodesma donacium, a clam found in the Southern Pacific. These strains were identified phylogenetically as belonging to the genera Aeromonas, Pseudomonas, Chryseobacterium, and Raoultella. The cellulase-producing capacities of these strains were characterized, and the degradation of cell walls in Botryococcus braunii and Nannochloropsis gaditana was tested with “whole-cell” cellulolytic experiments. Aeromonas bivalvium MA2, Raoultella ornithinolytica MA5, and Aeromonas salmonicida MC25 degraded B. braunii, and R. ornithinolytica MC3 and MA5 degraded N. gaditana. In addition, N. gaditana was pretreated with R. ornithinolytica strains MC3 and MA5 and was then subjected to an anaerobic digestion process, which increased the yield of methane by 140.32% and 158.68%, respectively, over that from nonpretreated microalgae. Therefore, a “whole-cell” cellulolytic pretreatment can increase the performance and efficiency of biogas production. PMID:24795376

  9. Microalgal Photosynthesis and Spectral Scalar Irradiance in Coastal Marine-Sediments of Limfjorden, Denmark

    DEFF Research Database (Denmark)

    LASSEN, C.; PLOUG, H.; JØRGENSEN, BB

    1992-01-01

    (bacteriochlorophyll a). Infrared scalar irradiance reached 200% of incident light intensity at 0.0-0.3-mm depth and IR penetration was independent of the development of a cyanobacterial surface film. At high incident light intensity, 740 muEinst m-2 s-1, the photosynthetic efficiency at 1.0-mm depth was 10-fold...... higher than in the uppermost 0.0-0.6 mm of the sediment. The lower boundary of the euphotic zone (detectable gross photosynthesis) was at a mean light level of greater-than-or-equal-to 7.5 muEinst m-2 s-1.......Scalar irradiance and oxygenic photosynthesis were measured simultaneously at 100-mum spatial resolution by a fiber-optic scalar irradiance microsensor and an oxygen microelectrode spaced 120 mum apart. Marine microbial mats on sandy sediments along the coast of Limfjorden, Denmark, were dominated...

  10. A New, Sensitive Marine Microalgal Recombinant Biosensor Using Luminescence Monitoring for Toxicity Testing of Antifouling Biocides

    Science.gov (United States)

    Sanchez-Ferandin, Sophie; Leroy, Fanny; Bouget, François-Yves

    2013-01-01

    In this study, we propose the use of the marine green alga Ostreococcus tauri, the smallest free-living eukaryotic cell known to date, as a new luminescent biosensor for toxicity testing in the environment. Diuron and Irgarol 1051, two antifouling biocides commonly encountered in coastal waters, were chosen to test this new biosensor along with two degradation products of diuron. The effects of various concentrations of the antifoulants on four genetic constructs of O. tauri (based on genes involved in photosynthesis, cell cycle, and circadian clock) were compared using 96-well culture microplates and a luminometer to automatically measure luminescence over 3 days. This was compared to growth inhibition of O. tauri wild type under the same conditions. Luminescence appeared to be more sensitive than growth inhibition as an indicator of toxicity. Cyclin-dependent kinase (CDKA), a protein involved in the cell cycle, fused to luciferase (CDKA-Luc) was found to be the most sensitive of the biosensors, allowing an accurate determination of the 50% effective concentration (EC50) after only 2 days (diuron, 5.65 ± 0.44 μg/liter; Irgarol 1015, 0.76 ± 0.10 μg/liter). The effects of the antifoulants on the CDKA-Luc biosensor were then compared to growth inhibition in natural marine phytoplankton. The effective concentrations of diuron and Irgarol 1051 were found to be similar, indicating that this biosensor would be suitable as a reliable ecotoxicological test. The advantage of this biosensor over cell growth inhibition testing is that the process can be easily automated and could provide a high-throughput laboratory approach to perform short-term toxicity tests. The ability to genetically transform and culture recombinant O. tauri gives it huge potential for screening many other toxic compounds. PMID:23144143

  11. Dynamics of microalgal communities in the water-column/sediment interface of the inner shelf off Parana State, Southern Brazil

    Directory of Open Access Journals (Sweden)

    Ricardo Luiz Queiroz

    2004-12-01

    Full Text Available The composition and biomass of the microalgal community at the water-column/sediment interface on the continental shelf off Parana State (Brazil were studied every 2 months during 1999. Samples for cell identification and determination of chlorophyll a were taken from the interface layer and at discrete depths up to 4 m above the sediment. Results showed a community mainly formed by benthic and planktonic diatoms >30 µm, benthic diatoms 30 µm, which accounted for most of the pigment biomass, were resuspended from the interface after turbulent periods, and may take advantage of calm periods to stay and grow at the interface. Small benthic diatoms were more susceptible to wind-induced turbulence occurring in higher densities in the water column just above the water-sediment interface. A cyanobacterial bloom (Trichodesmiun was observed at these bottom layers in the spring-summer periods.A composição geral e a biomassa da comunidade microalgal da interface sedimento/água da plataforma do Estado do Paraná (Brasil foram estudadas em 1999 em relação ao regime de ventos. A cada dois meses foram coletadas amostras para a identificação de organismos e determinação de clorofila a, na interface água-sedimento e em profundidades discretas, ao longo da coluna d'água, até 4m acima do sedimento. Os resultados obtidos revelaram uma comunidade constituída principalmente por diatomáceas planctônicas e bentônicas maiores que 30 µm, diatomáceas bentônicas menores que 30 µm, e cianobactérias coloniais. As densidades celulares foram geralmente mais altas na interface. Eventos de mistura e sedimentação parecem ser determinantes na regulação da composição e biomassa de tais comunidades. Formas menores, mais susceptíveis à turbulência, dominaram a comunidade de água de fundo na maioria das ocasiões, e foram as mais abundantes na interface apenas em períodos de extrema estabilidade. Células maiores, aparentemente contendo a maior parte

  12. Community-level microalgal toxicity assessment by multiwavelength-excitation PAM fluorometry

    International Nuclear Information System (INIS)

    Schmitt-Jansen, Mechthild; Altenburger, Rolf

    2008-01-01

    In ecotoxicological studies involving community-level investigations, rapid and multiparametric fluorescence-based methods may provide substantial advantages over traditional methods used for structural and functional community analysis. Therefore, multiwavelength-excitation pulse-amplitude modulated (PAM) fluorometry was applied in this study to assess long-term changes in periphyton community structure, short-term effects on periphyton functioning (photosynthesis) and pollution induced community tolerance (PICT). For inter-calibration, periphyton structure was evaluated by chemotaxonomic analysis of accessory pigments and a four-wavelength-excitation PAM fluorometer. Short-term effects of herbicides were evaluated by fluorescence quenching analysis and 14 C-incorporation as a proxy of primary production. Subsequently, the method was applied to assess structural and functional changes in periphyton communities after isoproturon exposure for 14 and 26 days, respectively. Results showed good correlation of the PAM fluorescence-based measurements with traditional methods for biofilms in the initial colonisation phase for structural and functional parameters. However, for biofilms older than 9 weeks PAM fluorescence may underestimate biomass. Multiwavelength-excitation PAM fluorometry showed good correlation with marker pigment concentrations indicating that this method provides a reliable estimate of the community structure. PAM fluorometry was able to quantify changes of biomass and follow relative shifts in class composition of biofilms under exposure of isoproturon. Short-term tests based on the quantification of the inhibition of the effective quantum yield revealed a concentration-dependent increase of PICT. The observation of two succession phases of the biofilms after 14 and 26 days of growth, respectively, revealed that sensitivity of biofilms decreased with increasing age and biomass, respectively, but PICT remained a characteristic parameter of exposed

  13. Community-level microalgal toxicity assessment by multiwavelength-excitation PAM fluorometry

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt-Jansen, Mechthild [UFZ-Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318 Leipzig (Germany)], E-mail: Mechthild.Schmitt@ufz.de; Altenburger, Rolf [UFZ-Helmholtz Centre for Environmental Research, Department of Bioanalytical Ecotoxicology, Permoserstr. 15, 04318 Leipzig (Germany)

    2008-01-20

    In ecotoxicological studies involving community-level investigations, rapid and multiparametric fluorescence-based methods may provide substantial advantages over traditional methods used for structural and functional community analysis. Therefore, multiwavelength-excitation pulse-amplitude modulated (PAM) fluorometry was applied in this study to assess long-term changes in periphyton community structure, short-term effects on periphyton functioning (photosynthesis) and pollution induced community tolerance (PICT). For inter-calibration, periphyton structure was evaluated by chemotaxonomic analysis of accessory pigments and a four-wavelength-excitation PAM fluorometer. Short-term effects of herbicides were evaluated by fluorescence quenching analysis and {sup 14}C-incorporation as a proxy of primary production. Subsequently, the method was applied to assess structural and functional changes in periphyton communities after isoproturon exposure for 14 and 26 days, respectively. Results showed good correlation of the PAM fluorescence-based measurements with traditional methods for biofilms in the initial colonisation phase for structural and functional parameters. However, for biofilms older than 9 weeks PAM fluorescence may underestimate biomass. Multiwavelength-excitation PAM fluorometry showed good correlation with marker pigment concentrations indicating that this method provides a reliable estimate of the community structure. PAM fluorometry was able to quantify changes of biomass and follow relative shifts in class composition of biofilms under exposure of isoproturon. Short-term tests based on the quantification of the inhibition of the effective quantum yield revealed a concentration-dependent increase of PICT. The observation of two succession phases of the biofilms after 14 and 26 days of growth, respectively, revealed that sensitivity of biofilms decreased with increasing age and biomass, respectively, but PICT remained a characteristic parameter of exposed

  14. Community Involvement in Marine Protected Areas.

    Science.gov (United States)

    Kaza, Stephanie

    1988-01-01

    Lists several key concepts in developing successful interpretive programs for marine protected areas with community involvement. Identifies educational tools that help foster community involvement in conservation and management. Cites three model programs. Sets standards and goals for international success including leadership, education,…

  15. Marine Invertebrates: Communities at Risk

    Directory of Open Access Journals (Sweden)

    Jennifer Mather

    2013-06-01

    Full Text Available Our definition of the word ‘animal’ centers on vertebrates, yet 99% of the animals on the planet are invertebrates, about which we know little. In addition, although the Census of Marine Life (COML.org has recently conducted an extensive audit of marine ecosystems, we still do not understand much about the animals of the seas. Surveys of the best-known ecosystems, in which invertebrate populations often play a key role, show that the invertebrate populations are affected by human impact. Coral animals are the foundation of coral reef systems, which are estimated to contain 30% of the species in the ocean. Physical impact and chemical changes on the water severely damage these reefs, and may lead to the removal of these important habitats. Tiny pteropod molluscs live in huge numbers in the polar seas, and their fragile shells are particularly vulnerable to ocean acidification. Their removal would mean that fishes on which we depend would have a hugely diminished food supply. In the North Sea, warming is leading to replacement of colder water copepods by warmer water species which contain less fat. This is having an effect on the birds which eat them, who enrich the otherwise poor land on which they nest. Conversely, the warming of the water and the loss of top predators such as whales and sharks has led to an explosion of the jumbo squid of the Pacific coast of North America. This is positive in the development of a squid fishery, yet negative because the squid eat fish that have been the mainstay of the fishery along that coast. These examples show how invertebrates are key in the oceans, and what might happen when global changes impact them.

  16. Marine invertebrates: communities at risk.

    Science.gov (United States)

    Mather, Jennifer

    2013-06-10

    Our definition of the word 'animal' centers on vertebrates, yet 99% of the animals on the planet are invertebrates, about which we know little. In addition, although the Census of Marine Life (COML.org) has recently conducted an extensive audit of marine ecosystems, we still do not understand much about the animals of the seas. Surveys of the best-known ecosystems, in which invertebrate populations often play a key role, show that the invertebrate populations are affected by human impact. Coral animals are the foundation of coral reef systems, which are estimated to contain 30% of the species in the ocean. Physical impact and chemical changes on the water severely damage these reefs, and may lead to the removal of these important habitats. Tiny pteropod molluscs live in huge numbers in the polar seas, and their fragile shells are particularly vulnerable to ocean acidification. Their removal would mean that fishes on which we depend would have a hugely diminished food supply. In the North Sea, warming is leading to replacement of colder water copepods by warmer water species which contain less fat. This is having an effect on the birds which eat them, who enrich the otherwise poor land on which they nest. Conversely, the warming of the water and the loss of top predators such as whales and sharks has led to an explosion of the jumbo squid of the Pacific coast of North America. This is positive in the development of a squid fishery, yet negative because the squid eat fish that have been the mainstay of the fishery along that coast. These examples show how invertebrates are key in the oceans, and what might happen when global changes impact them.

  17. Microalgal Culture Collection Transfers

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Milford Microalgal culture Collection holds over 200 live cultures representing 13 classes of of algae. The cultures are maintained in three different growing...

  18. Harvesting Environmental Microalgal Blooms for Remediation and Resource Recovery: A Laboratory Scale Investigation with Economic and Microbial Community Impact Assessment

    Directory of Open Access Journals (Sweden)

    Jagroop Pandhal

    2017-12-01

    Full Text Available A laboratory based microflotation rig termed efficient FLOtation of Algae Technology (eFLOAT was used to optimise parameters for harvesting microalgal biomass from eutrophic water systems. This was performed for the dual objectives of remediation (nutrient removal and resource recovery. Preliminary experiments demonstrated that chitosan was more efficient than alum for flocculation of biomass and the presence of bacteria could play a positive role and reduce flocculant application rates under the natural conditions tested. Maximum biomass removal from a hyper-eutrophic water retention pond sample was achieved with 5 mg·L−1 chitosan (90% Chlorophyll a removal. Harvesting at maximum rates showed that after 10 days, the bacterial diversity is significantly increased with reduced cyanobacteria, indicating improved ecosystem functioning. The resource potential within the biomass was characterized by 9.02 μg phosphate, 0.36 mg protein, and 103.7 μg lipid per mg of biomass. Fatty acid methyl ester composition was comparable to pure cultures of microalgae, dominated by C16 and C18 chain lengths with saturated, monounsaturated, and polyunsaturated fatty acids. Finally, the laboratory data was translated into a full-size and modular eFLOAT system, with estimated costs as a novel eco-technology for efficient algal bloom harvesting.

  19. European Community's program in marine resources development

    International Nuclear Information System (INIS)

    Lenoble, J.P.; Jarmache, E.

    1995-01-01

    The European Community launched already several research program in the different fields of social and industrial activities. The Fourth Framework Programme is divided into 4 main activities comporting a total of 18 programs. These programs are dealing with general topics as information and communication, industrial technologies, environment, life sciences and technologies, energy, transport and socioeconomic research. One line is devoted to marine sciences and technology, but offshore activities could also be included in the other topics as offshore oil and gas in energy, ship building and harbor in transport, aquaculture and fisheries in life sciences and technology, etc. In order to maintain a coherent approach toward offshore activities, the European maritime industries met intensively front 1991 to 1994 and recommended a series of proposal for Research and Development of marine resources. The methodology and content of these proposals is exposed

  20. Modeling of microalgal metabolism

    NARCIS (Netherlands)

    Kliphuis, A.M.J.

    2010-01-01

    Microalgae are a potential source for a wide range of products, such as carotenoids, lipids, hydrogen, protein and starch, which are of interest for food, feed and biofuel applications. Maximization of microalgal product and biomass productivity in (large-scale) outdoor photobioreactors is important

  1. Effects of temperature and irradiance on a benthic microalgal community: A combined two-dimensional oxygen and fluorescence imaging approach

    DEFF Research Database (Denmark)

    Hancke, Kasper; Sorrell, Brian Keith; Lund-Hansen, Lars Chresten

    2014-01-01

    The effects of temperature and light on both oxygen (O2) production and gross photosynthesis were resolved in a benthic microalgae community by combining two-dimensional (2D) imaging of O2 and variable chlorophyll a (Chl a) fluorescence. Images revealed a photosynthetically active community...... microbial community, at different temperatures. The present imaging approach demonstrates a great potential to study consequences of environmental effects on photosynthetic activity and O2 turnover in complex phototrophic benthic communities....

  2. Microalgal biofilms for wastewater treatment

    NARCIS (Netherlands)

    Boelee, N.C.

    2013-01-01

    The objective of this thesis was to explore the possibilities of using microalgal biofilms for the treatment of municipal wastewater, with a focus on the post-treatment of municipal wastewater effluent. The potential of microalgal biofilms for wastewater treatment was first investigated using a

  3. Chemical composition - Sustainable aquafeeds for marine finfish: Effects of vegetable oil replacement feeds containing novel microalgal and fungal oils on growth performance of juvenile sablefish

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The concomitant replacement of fish meal and fish oil in carnivorous marine fish feeds by more sustainable terrestrial alternatives is problematic due to the limited...

  4. Lipid composition - Sustainable aquafeeds for marine finfish: Effects of vegetable oil replacement feeds containing novel microalgal and fungal oils on growth performance of juvenile sablefish

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The concomitant replacement of fish meal and fish oil in carnivorous marine fish feeds by more sustainable terrestrial alternatives is problematic due to the limited...

  5. Growth - Sustainable aquafeeds for marine finfish: Effects of vegetable oil replacement feeds containing novel microalgal and fungal oils on growth performance of juvenile sablefish

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The concomitant replacement of fish meal and fish oil in carnivorous marine fish feeds by more sustainable terrestrial alternatives is problematic due to the limited...

  6. Marine protected areas increase resilience among coral reef communities.

    Science.gov (United States)

    Mellin, Camille; Aaron MacNeil, M; Cheal, Alistair J; Emslie, Michael J; Julian Caley, M

    2016-06-01

    With marine biodiversity declining globally at accelerating rates, maximising the effectiveness of conservation has become a key goal for local, national and international regulators. Marine protected areas (MPAs) have been widely advocated for conserving and managing marine biodiversity yet, despite extensive research, their benefits for conserving non-target species and wider ecosystem functions remain unclear. Here, we demonstrate that MPAs can increase the resilience of coral reef communities to natural disturbances, including coral bleaching, coral diseases, Acanthaster planci outbreaks and storms. Using a 20-year time series from Australia's Great Barrier Reef, we show that within MPAs, (1) reef community composition was 21-38% more stable; (2) the magnitude of disturbance impacts was 30% lower and (3) subsequent recovery was 20% faster that in adjacent unprotected habitats. Our results demonstrate that MPAs can increase the resilience of marine communities to natural disturbance possibly through herbivory, trophic cascades and portfolio effects. © 2016 John Wiley & Sons Ltd/CNRS.

  7. Progress and Challenges in Microalgal Biodiesel Production

    Science.gov (United States)

    Mallick, Nirupama; Bagchi, Sourav K.; Koley, Shankha; Singh, Akhilesh K.

    2016-01-01

    The last decade has witnessed a tremendous impetus on biofuel research due to the irreversible diminution of fossil fuel reserves for enormous demands of transportation vis-a-vis escalating emissions of green house gasses (GHGs) into the atmosphere. With an imperative need of CO2 reduction and considering the declining status of crude oil, governments in various countries have not only diverted substantial funds for biofuel projects but also have introduced incentives to vendors that produce biofuels. Currently, biodiesel production from microalgal biomass has drawn an immense importance with the potential to exclude high-quality agricultural land use and food safe-keeping issues. Moreover, microalgae can grow in seawater or wastewater and microalgal oil can exceed 50–60% (dry cell weight) as compared with some best agricultural oil crops of only 5–10% oil content. Globally, microalgae are the highest biomass producers and neutral lipid accumulators contending any other terrestrial oil crops. However, there remain many hurdles in each and every step, starting from strain selection and lipid accumulation/yield, algae mass cultivation followed by the downstream processes such as harvesting, drying, oil extraction, and biodiesel conversion (transesterification), and overall, the cost of production. Isolation and screening of oleaginous microalgae is one pivotal important upstream factor which should be addressed according to the need of freshwater or marine algae with a consideration that wild-type indigenous isolate can be the best suited for the laboratory to large scale exploitation. Nowadays, a large number of literature on microalgal biodiesel production are available, but none of those illustrate a detailed step-wise description with the pros and cons of the upstream and downstream processes of biodiesel production from microalgae. Specifically, harvesting and drying constitute more than 50% of the total production costs; however, there are quite a less

  8. Microalgal distribution, diversity and photo-physiological ...

    African Journals Online (AJOL)

    Microalgal distribution, diversity and photo-physiological performance across five ... D'Esny (MAPD), the sandy beach of Blue Bay (SBBB) and the estuarine area of Le ... Microalgal density in the water column (micro-phytoplankton) was highest in ... Diatom was the most abundant microalgal group, followed by dinoflagellate ...

  9. Life in the "plastisphere": microbial communities on plastic marine debris.

    Science.gov (United States)

    Zettler, Erik R; Mincer, Tracy J; Amaral-Zettler, Linda A

    2013-07-02

    Plastics are the most abundant form of marine debris, with global production rising and documented impacts in some marine environments, but the influence of plastic on open ocean ecosystems is poorly understood, particularly for microbial communities. Plastic marine debris (PMD) collected at multiple locations in the North Atlantic was analyzed with scanning electron microscopy (SEM) and next-generation sequencing to characterize the attached microbial communities. We unveiled a diverse microbial community of heterotrophs, autotrophs, predators, and symbionts, a community we refer to as the "Plastisphere". Pits visualized in the PMD surface conformed to bacterial shapes suggesting active hydrolysis of the hydrocarbon polymer. Small-subunit rRNA gene surveys identified several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in degrading PMD. Some Plastisphere members may be opportunistic pathogens (the authors, unpublished data) such as specific members of the genus Vibrio that dominated one of our plastic samples. Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.

  10. Biodiesel production by microalgal biotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Huang, GuanHua [School of Chemical Engineering and Technology, China University of Mining and Technology (China); Chen, Feng [School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong (China); College of Light Industry and Food Sciences, South China University of Technology, Guangzhou (China); Wei, Dong; Zhang, XueWu; Chen, Gu [College of Light Industry and Food Sciences, South China University of Technology, Guangzhou (China)

    2010-01-15

    Biodiesel has received much attention in recent years. Although numerous reports are available on the production of biodiesel from vegetable oils of terraneous oil-plants, such as soybean, sunflower and palm oils, the production of biodiesel from microalgae is a newly emerging field. Microalgal biotechnology appears to possess high potential for biodiesel production because a significant increase in lipid content of microalgae is now possible through heterotrophic cultivation and genetic engineering approaches. This paper provides an overview of the technologies in the production of biodiesel from microalgae, including the various modes of cultivation for the production of oil-rich microalgal biomass, as well as the subsequent downstream processing for biodiesel production. The advances and prospects of using microalgal biotechnology for biodiesel production are discussed. (author)

  11. A glimpse into the future composition of marine phytoplankton communities

    Directory of Open Access Journals (Sweden)

    Esteban eAcevedo-Trejos

    2014-07-01

    Full Text Available It is expected that climate change will have significant impacts on ecosystems. Most model projections agree that the ocean will experience stronger stratification and less nutrient supply from deep waters. These changes will likely affect marine phytoplankton communities and will thus impact on the higher trophic levels of the oceanic food web. The potential consequences of future climate change on marine microbial communities can be investigated and predicted only with the help of mathematical models. Here we present the application of a model that describes aggregate properties of marine phytoplankton communities and captures the effects of a changing environment on their composition and adaptive capacity. Specifically, the model describes the phytoplankton community in terms of total biomass, mean cell size, and functional diversity. The model is applied to two contrasting regions of the Atlantic Ocean (tropical and temperate and is tested under two emission scenarios: SRES A2 or ``business as usual'' and SRES B1 or ``local utopia''. We find that all three macroecological properties will decline during the next century in both regions, although this effect will be more pronounced in the temperate region. Being consistent with previous model predictions, our results show that a simple trait-based modelling framework represents a valuable tool for investigating how phytoplankton communities may reorganize under a changing climate.

  12. Strong seasonality and interannual recurrence in marine myovirus communities.

    Science.gov (United States)

    Pagarete, A; Chow, C-E T; Johannessen, T; Fuhrman, J A; Thingstad, T F; Sandaa, R A

    2013-10-01

    The temporal community dynamics and persistence of different viral types in the marine environment are still mostly obscure. Polymorphism of the major capsid protein gene, g23, was used to investigate the community composition dynamics of T4-like myoviruses in a North Atlantic fjord for a period of 2 years. A total of 160 unique operational taxonomic units (OTUs) were identified by terminal restriction fragment length polymorphism (TRFLP) of the gene g23. Three major community profiles were identified (winter-spring, summer, and autumn), which resulted in a clear seasonal succession pattern. These seasonal transitions were recurrent over the 2 years and significantly correlated with progression of seawater temperature, Synechococcus abundance, and turbidity. The appearance of the autumn viral communities was concomitant with the occurrence of prominent Synechococcus blooms. As a whole, we found a highly dynamic T4-like viral community with strong seasonality and recurrence patterns. These communities were unexpectedly dominated by a group of persistently abundant viruses.

  13. Differential response of marine flagellate communities to prokaryotic food quality

    Science.gov (United States)

    De Corte, D.; Paredes, G.; Sintes, E.; Herndl, G. J.

    2016-02-01

    Marine prokaryotes play a major role in the biogeochemical cycles. The main predators of prokaryotes are heterotrophic nanoflagellates (HNF). HNF are thus a major link connecting dissolved organic material through prokaryotic grazing to the higher trophic levels. However, little is known about the grazing specificity of HNF on specific prokaryotic taxa. Bacterial and archaeal microbes may have different nutritive values for the HNF communities, thus affecting growth rates and community composition of HNFs. In this study we investigated the influence of prey food quality on Cafeteria roenbergensis and on a natural HNF community isolated in the northern Adriatic Sea. Two Nitrosopumilus maritimus-related strains isolated from the northern Adriatic Sea (Nitrosopumilus adriaticus, Nitrosopumilus piranensis), two Nitrosococcus strains and two fast growing marine Bacteria (Pseudomonas marina and Marinobacter algicola) were fed to the HNFs. The two fast growing bacterial strains resulted in high growth rates of Cafeteria roenbergensis and the mixed HNF community, while the two Nitrosococcus strains did not. Cafeteria roenbergensis fed on N. adriaticus but it did not graze N. piranensis, suggesting that the subtle metabolic and physiological differences between these two closely related thaumarchaeal strains affect the grazing pressure to which they are exposed. Our study also indicates that prokaryotic community composition influences the composition of the HNF community.

  14. Co-cultivation of fungal and microalgal cells as an efficient system for harvesting microalgal cells, lipid production and wastewater treatment.

    Directory of Open Access Journals (Sweden)

    Digby Wrede

    Full Text Available The challenges which the large scale microalgal industry is facing are associated with the high cost of key operations such as harvesting, nutrient supply and oil extraction. The high-energy input for harvesting makes current commercial microalgal biodiesel production economically unfeasible and can account for up to 50% of the total cost of biofuel production. Co-cultivation of fungal and microalgal cells is getting increasing attention because of high efficiency of bio-flocculation of microalgal cells with no requirement for added chemicals and low energy inputs. Moreover, some fungal and microalgal strains are well known for their exceptional ability to purify wastewater, generating biomass that represents a renewable and sustainable feedstock for biofuel production. We have screened the flocculation efficiency of the filamentous fungus A. fumigatus against 11 microalgae representing freshwater, marine, small (5 µm, large (over 300 µm, heterotrophic, photoautotrophic, motile and non-motile strains. Some of the strains are commercially used for biofuel production. Lipid production and composition were analysed in fungal-algal pellets grown on media containing alternative carbon, nitrogen and phosphorus sources contained in wheat straw and swine wastewater, respectively. Co-cultivation of algae and A. fumigatus cells showed additive and synergistic effects on biomass production, lipid yield and wastewater bioremediation efficiency. Analysis of fungal-algal pellet's fatty acids composition suggested that it can be tailored and optimised through co-cultivating different algae and fungi without the need for genetic modification.

  15. Co-cultivation of fungal and microalgal cells as an efficient system for harvesting microalgal cells, lipid production and wastewater treatment.

    Science.gov (United States)

    Wrede, Digby; Taha, Mohamed; Miranda, Ana F; Kadali, Krishna; Stevenson, Trevor; Ball, Andrew S; Mouradov, Aidyn

    2014-01-01

    The challenges which the large scale microalgal industry is facing are associated with the high cost of key operations such as harvesting, nutrient supply and oil extraction. The high-energy input for harvesting makes current commercial microalgal biodiesel production economically unfeasible and can account for up to 50% of the total cost of biofuel production. Co-cultivation of fungal and microalgal cells is getting increasing attention because of high efficiency of bio-flocculation of microalgal cells with no requirement for added chemicals and low energy inputs. Moreover, some fungal and microalgal strains are well known for their exceptional ability to purify wastewater, generating biomass that represents a renewable and sustainable feedstock for biofuel production. We have screened the flocculation efficiency of the filamentous fungus A. fumigatus against 11 microalgae representing freshwater, marine, small (5 µm), large (over 300 µm), heterotrophic, photoautotrophic, motile and non-motile strains. Some of the strains are commercially used for biofuel production. Lipid production and composition were analysed in fungal-algal pellets grown on media containing alternative carbon, nitrogen and phosphorus sources contained in wheat straw and swine wastewater, respectively. Co-cultivation of algae and A. fumigatus cells showed additive and synergistic effects on biomass production, lipid yield and wastewater bioremediation efficiency. Analysis of fungal-algal pellet's fatty acids composition suggested that it can be tailored and optimised through co-cultivating different algae and fungi without the need for genetic modification.

  16. Marine and giant viruses as indicators of a marine microbial community in a riverine system.

    Science.gov (United States)

    Dann, Lisa M; Rosales, Stephanie; McKerral, Jody; Paterson, James S; Smith, Renee J; Jeffries, Thomas C; Oliver, Rod L; Mitchell, James G

    2016-12-01

    Viral communities are important for ecosystem function as they are involved in critical biogeochemical cycles and controlling host abundance. This study investigates riverine viral communities around a small rural town that influences local water inputs. Myoviridae, Siphoviridae, Phycodnaviridae, Mimiviridae, Herpesviridae, and Podoviridae were the most abundant families. Viral species upstream and downstream of the town were similar, with Synechoccocus phage, salinus, Prochlorococcus phage, Mimivirus A, and Human herpes 6A virus most abundant, contributing to 4.9-38.2% of average abundance within the metagenomic profiles, with Synechococcus and Prochlorococcus present in metagenomes as the expected hosts for the phage. Overall, the majority of abundant viral species were or were most similar to those of marine origin. At over 60 km to the river mouth, the presence of marine communities provides some support for the Baas-Becking hypothesis "everything is everywhere, but, the environment selects." We conclude marine microbial species may occur more frequently in freshwater systems than previously assumed, and hence may play important roles in some freshwater ecosystems within tens to a hundred kilometers from the sea. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  17. Bacterial communities in sediment of a Mediterranean marine protected area.

    Science.gov (United States)

    Catania, Valentina; Sarà, Gianluca; Settanni, Luca; Quatrini, Paola

    2017-04-01

    Biodiversity is crucial in preservation of ecosystems, and bacterial communities play an indispensable role for the functioning of marine ecosystems. The Mediterranean marine protected area (MPA) "Capo Gallo-Isola delle Femmine" was instituted to preserve marine biodiversity. The bacterial diversity associated with MPA sediment was compared with that from sediment of an adjacent harbour exposed to intense nautical traffic. The MPA sediment showed higher diversity with respect to the impacted site. A 16S rDNA clone library of the MPA sediment allowed the identification of 7 phyla: Proteobacteria (78%), Firmicutes (11%), Acidobacteria (3%), Actinobacteria (3%), Bacteroidetes (2%), Planctomycetes (2%), and Cyanobacteria (1%). Analysis of the hydrocarbon (HC)-degrading bacteria was performed using enrichment cultures. Most of the MPA sediment isolates were affiliated with Gram-positive G+C rich bacteria, whereas the majority of taxa in the harbour sediment clustered with Alpha- and Gammaproteobacteria; no Gram-positive HC degraders were isolated from the harbour sediment. Our results show that protection probably has an influence on bacterial diversity, and suggest the importance of monitoring the effects of protection at microbial level as well. This study creates a baseline of data that can be used to assess changes over time in bacterial communities associated with a Mediterranean MPA.

  18. Moving Toward Spatial Solutions in Marine Conservation with Indigenous Communities

    Directory of Open Access Journals (Sweden)

    Natalie C. Ban

    2008-06-01

    Full Text Available Community and resource user support has often been declared as essential to achieving globally agreed targets for marine protection. Given that indigenous people in Canada have resource use rights, we engaged two indigenous communities in British Columbia for their views on marine planning and protected areas. We developed a three-phased approach for executing our research: building research partnerships, carrying out individual interviews, and holding community discussion sessions. Participants expressed a common goal of recovering depleted species and ensuring the sustainability of indigenous fishing. We found strong support for spatial protection measures, and significant overlaps amongst participants in the areas suggested for protection. The most common type of protection recommended by participants was the exclusion of commercial and recreational fisheries while allowing for indigenous fishing; this stands in contrast to the emphasis on strict no-take MPAs advocated in the literature. Similarities in the goal, and level and areas of protection point to a gap in conservation approaches: the conservation of important areas and resources to indigenous people, allowing the continued practice and adaptation of their culture.

  19. COMPLEXITY OF ECOLOGICAL SYSTEMS (THE CASE OF MARINE CILIATE COMMUNITY

    Directory of Open Access Journals (Sweden)

    I.V. Burkovsky

    2016-03-01

    Full Text Available The paper analyzes the seasonal and long-term dynamics of marine interstitial ciliates communities as a result of the processes of system self-organization (of increasing complexity in constantly fluctuating environment. The traits of simple structure of ciliate community include substantial variability in the composition (even in case of stable environment and the lack of sustainable combinations of species. The mechanism of the current state maintenance is the lack of energy supply in certain periods or in specific loci of space, as well as large amplitude and unpredictable fluctuations of environmental factors. An indication of the community’s complexity is availability of stable combinations of species in time and space. The mechanisms of formation of stable species combinations are a constant flow of external energy, optimal values and stability of environmental factors (including repeatability of seasonal cycles and the use of space resources by species according the principle of complementarity of ecological niches.

  20. Microalgal Mass Culture Room Harvest Records

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The microalgal mass culture room, housed at the NOAA Fisheries' Milford CT laboratory, provides research grade microalgae (phytoplankton) to in-house and...

  1. Marine snow microbial communities: scaling of abundances with aggregate size

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    2003-01-01

    Marine aggregates are inhabited by diverse microbial communities, and the concentration of attached microbes typically exceeds concentrations in the ambient water by orders of magnitude. An extension of the classical Lotka-Volterra model, which includes 3 trophic levels (bacteria, flagellates...... are controlled by flagellate grazing, while flagellate and ciliate populations are governed by colonization and detachment. The model also suggests that microbial populations are turned over rapidly (1 to 20 times d-1) due to continued colonization and detachment. The model overpredicts somewhat the scaling...... of microbial abundances with aggregate size observed in field-collected aggregates. This may be because it disregards the aggregation/disaggregation dynamics of aggregates, as well as interspecific interactions between bacteria....

  2. Informing and involving: the community`s right to know [marine oil spills

    Energy Technology Data Exchange (ETDEWEB)

    Watson, G. [Marine and Coastal Community Network, Perth, WA (Australia)

    1996-12-31

    The Marine and Coastal Community Network was established in 1993 to facilitate communication between all user groups of Australia`s coasts and seas, to promote ecological sustainability, to encourage greater community involvement, and to provide information. It is proving successful in providing a line of communication between a broad range of sectorial interests and developing a cooperative approach to ecological sustainability. This paper addresses the question of how the oil industry is shaping up in relation to providing relevant, accessible, understandable and up-to-date information to the community, in involving the community, and in developing and delivering industry best practice. It also outlines what the community wants to know and what industry can do better. The community, it is concluded, is always going to react very strongly over oil spills. Maintenance of water quality and the conservation of Australia`s coastline are extremely important issues for the community. A greater willingness to involve the community and a greater commitment to better research and practices is considered necessary. (author). 1 tab., 1 fig., 20 refs.

  3. Ecology of selected marine communities in Glacier Bay: Zooplankton, forage fish, seabirds and marine mammals

    Science.gov (United States)

    Robards, Martin D.; Drew, Gary S.; Piatt, John F.; Anson, Jennifer Marie; Abookire, Alisa A.; Bodkin, James L.; Hooge, Philip N.; Speckman, Suzann G.

    2003-01-01

    We studied oceanography (including primary production), secondary production, small schooling fish (SSF), and marine bird and mammal predators in Glacier Bay during 1999 and 2000. Results from these field efforts were combined with a review of current literature relating to the Glacier Bay environment. Since the conceptual model developed by Hale and Wright (1979) ‘changes and cycles’ continue to be the underlying theme of the Glacier Bay ecosystem. We found marked seasonality in many of the parameters that we investigated over the two years of research, and here we provide a comprehensive description of the distribution and relative abundance of a wide array of marine biota. Glacier Bay is a tidally mixed estuary that leads into basins, which stratify in summer, with the upper arms behaving as traditional estuaries. The Bay is characterized by renewal and mixing events throughout the year, and markedly higher primary production than in many neighboring southeast Alaska fjords (Hooge and Hooge, 2002). Zooplankton diversity and abundance within the upper 50 meters of the water column in Glacier Bay is similar to communities seen throughout the Gulf of Alaska. Zooplankton in the lower regions of Glacier Bay peak in abundance in late May or early June, as observed at Auke Bay and in the Gulf of Alaska. The key distinction between the lower Bay and other estuaries in the Gulf of Alaska is that a second smaller peak in densities occurs in August. The upper Bay behaved uniformly in temporal trends, peaking in July. Densities had begun to decline in August, but were still more than twice those observed in that region in May. The highest density of zooplankton observed was 17,870 organisms/m3 in Tarr Inlet during July. Trends in zooplankton community abundance and diversity within the lower Bay were distinct from upper-Glacier Bay trends. Whereas the lower Bay is strongly influenced by Gulf of Alaska processes, local processes are the strongest influence in the upper

  4. Microalgal production - A close look at the economics

    NARCIS (Netherlands)

    Norsker, N.H.; Barbosa, M.J.; Vermuë, M.H.; Wijffels, R.H.

    2011-01-01

    Worldwide, microalgal biofuel production is being investigated. It is strongly debated which type of production technology is the most adequate. Microalgal biomass production costs were calculated for 3 different micro algal production systems operating at commercial scale today: open ponds,

  5. A comparative study: the impact of different lipid extraction methods on current microalgal lipid research

    Science.gov (United States)

    2014-01-01

    Microalgae cells have the potential to rapidly accumulate lipids, such as triacylglycerides that contain fatty acids important for high value fatty acids (e.g., EPA and DHA) and/or biodiesel production. However, lipid extraction methods for microalgae cells are not well established, and there is currently no standard extraction method for the determination of the fatty acid content of microalgae. This has caused a few problems in microlagal biofuel research due to the bias derived from different extraction methods. Therefore, this study used several extraction methods for fatty acid analysis on marine microalga Tetraselmis sp. M8, aiming to assess the potential impact of different extractions on current microalgal lipid research. These methods included classical Bligh & Dyer lipid extraction, two other chemical extractions using different solvents and sonication, direct saponification and supercritical CO2 extraction. Soxhlet-based extraction was used to weigh out the importance of solvent polarity in the algal oil extraction. Coupled with GC/MS, a Thermogravimetric Analyser was used to improve the quantification of microalgal lipid extractions. Among these extractions, significant differences were observed in both, extract yield and fatty acid composition. The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids. The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research. PMID:24456581

  6. Biomass and Neutral Lipid Production in Geothermal Microalgal Consortia

    Science.gov (United States)

    Bywaters, Kathryn F.; Fritsen, Christian H.

    2015-01-01

    Recently, technologies have been developed that offer the possibility of using algal biomass as feedstocks to energy producing systems – in addition to oil-derived fuels (Bird et al., 2011, 2012). Growing native mixed microalgal consortia for biomass in association with geothermal resources has the potential to mitigate negative impacts of seasonally low temperatures on biomass production systems as well as mitigate some of the challenges associated with growing unialgal strains. We assessed community composition, growth rates, biomass, and neutral lipid production of microalgal consortia obtained from geothermal hot springs in the Great Basin/Nevada area that were cultured under different thermal and light conditions. Biomass production rates ranged from 39.0 to 344.1 mg C L−1 day−1. The neutral lipid production in these consortia with and without shifts to lower temperatures and additions of bicarbonate (both environmental parameters that have been shown to enhance neutral lipid production) ranged from 0 to 38.74 mg free fatty acids (FFA) and triacylglycerols (TAG) L−1 day−1; the upper value was approximately 6% of the biomass produced. The higher lipid values were most likely due to the presence of Achnanthidium sp. Palmitic and stearic acids were the dominant free fatty acids. The S/U ratio (the saturated to unsaturated FA ratio) decreased for cultures shifted from their original temperature to 15°C. Biomass production was within the upper limits of those reported for individual strains, and production of neutral lipids was increased with secondary treatment. All results demonstrate a potential of culturing and manipulating resultant microalgal consortia for biomass-based energy production and perhaps even for biofuels. PMID:25763368

  7. Biomass and Neutral Lipid Production in Geothermal Microalgal Consortia

    Directory of Open Access Journals (Sweden)

    Kathryn Faye Bywaters

    2015-02-01

    Full Text Available Recently, technologies have been developed that offer the possibility of using algal biomass as feedstocks to energy producing systems- in addition to oil-derived fuels (Bird et al., 2011;Bird et al., 2012. Growing native mixed microalgal consortia for biomass in association with geothermal resources has the potential to mitigate negative impacts of seasonally low temperatures on biomass production systems as well as mitigate some of the challenges associated with growing unialgal strains. We assessed community composition, growth rates, biomass and neutral lipid production of microalgal consortia obtained from geothermal hot springs in the Great Basin/Nevada area that were cultured under different thermal and light conditions. Biomass production rates ranged from 368 to 3246 mg C L-1 d-1. The neutral lipid production in these consortia with and without shifts to lower temperatures and additions of bicarbonate (both environmental parameters that have been shown to enhance neutral lipid production ranged from zero to 38.74 mg free fatty acids and triacylglycerols L-1 d-1, the upper value was approximately 6% of the biomass produced. The higher lipid values were most likely due to the presence of Achnanthidium sp. Palmitic and stearic acids were the dominant free fatty acids. The S/U ratio (the saturated to unsaturated FA ratio decreased for cultures shifted from their original temperature to 15°C. Biomass production was within the upper limits of those reported for individual strains, and production of neutral lipids was increased with secondary treatment – all results demonstrate a potential of culturing and manipulating resultant microalgal consortia for biomass-based energy production and perhaps even for biofuels.

  8. Women in the United States Marine Corps CI/HUMINT Community

    National Research Council Canada - National Science Library

    Reese, Jackson L

    2008-01-01

    The purpose of the researchers Masters of Military Arts and Science thesis is to explore the possibility of including women in the Marine Corps CI/HUMINT community without diminishing the overall unit...

  9. Learning from disaster: Community-based marine protected areas in Fiji

    OpenAIRE

    Yoshito Takasaki

    2013-01-01

    This paper empirically examines whether and how experiencing climate-related disasters can improve the rural poor fs adaptation to climate change through community-based resource management. Original household survey data in Fiji capture the unique sequence of a tropical cyclone and the establishment of community-based marine protected areas as a natural experiment. The analysis reveals that household disaster victimization increases its support for establishing marine protected areas for fut...

  10. Microalgal toxin(s): characteristics and importance

    African Journals Online (AJOL)

    Prokaryotic and eukaryotic microalgae produce a wide array of compounds with biological activities. These include antibiotics, algicides, toxins, pharmaceutically active compounds and plant growth regulators. Toxic microalgae, in this sense, are common only among the cyanobacteria and dinoflagellates. The microalgal ...

  11. Towards microalgal triglycerides in the commodity markets

    NARCIS (Netherlands)

    Benvenuti, Giulia; Ruiz, Jesús; Lamers, Packo P.; Bosma, Rouke; Wijffels, René H.; Barbosa, Maria J.

    2017-01-01

    Background: Microalgal triglycerides (TAGs) hold great promise as sustainable feedstock for commodity industries. However, to determine research priorities and support business decisions, solid techno-economic studies are essential. Here, we present a techno-economic analysis of two-step TAG

  12. Status of Coral Reef Fish Communities within the Mombasa Marine ...

    African Journals Online (AJOL)

    investigated in the Mombasa Marine Protected Area (MPA) on the Kenya coast ... in 1991 in an urban and tourism development ... Coast Province of Kenya in ..... environmental factors such as salinity and ... SEM when sampling is difficult.

  13. Preliminary study on the dye removal efficacy of immobilized marine ...

    African Journals Online (AJOL)

    Preliminary study on the dye removal efficacy of immobilized marine and freshwater microalgal beads from textile wastewater. SD Kumar, P Santhanam, R Nandakumar, S Anath, B Balaji Prasath, A Shenbaga Devi, S Jeyanthi, T Jayalakshima, P Ananthi ...

  14. Microalgal cultivation with biogas slurry for biofuel production.

    Science.gov (United States)

    Zhu, Liandong; Yan, Cheng; Li, Zhaohua

    2016-11-01

    Microalgal growth requires a substantial amount of chemical fertilizers. An alternative to the utilization of fertilizer is to apply biogas slurry produced through anaerobic digestion to cultivate microalgae for the production of biofuels. Plenty of studies have suggested that anaerobic digestate containing high nutrient contents is a potentially feasible nutrient source to culture microalgae. However, current literature indicates a lack of review available regarding microalgal cultivation with biogas slurry for the production of biofuels. To help fill this gap, this review highlights the integration of digestate nutrient management with microalgal production. It first unveils the current status of microalgal production, providing basic background to the topic. Subsequently, microalgal cultivation technologies using biogas slurry are discussed in detail. A scale-up scheme for simultaneous biogas upgrade and digestate application through microalgal cultivation is then proposed. Afterwards, several uncertainties that might affect this practice are explored. Finally, concluding remarks are put forward. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Patterns of distribution, abundance, and change over time in a subarctic marine bird community

    Science.gov (United States)

    Cushing, Daniel A.; Roby, Daniel D.; Irons, David B.

    2018-01-01

    Over recent decades, marine ecosystems of Prince William Sound (PWS), Alaska, have experienced concurrent effects of natural and anthropogenic perturbations, including variability in the climate system of the northeastern Pacific Ocean. We documented spatial and temporal patterns of variability in the summer marine bird community in relation to habitat and climate variability using boat-based surveys of marine birds conducted during the period 1989-2012. We hypothesized that a major factor structuring marine bird communities in PWS would be proximity to the shoreline, which is theorized to relate to aspects of food web structure. We also hypothesized that shifts in physical ecosystem drivers differentially affected nearshore-benthic and pelagic components of PWS food webs. We evaluated support for our hypotheses using an approach centered on community-level patterns of spatial and temporal variability. We found that an environmental gradient related to water depth and distance from shore was the dominant factor spatially structuring the marine bird community. Responses of marine birds to this onshore-offshore environmental gradient were related to dietary specialization, and separated marine bird taxa by prey type. The primary form of temporal variability over the study period was monotonic increases or decreases in abundance for 11 of 18 evaluated genera of marine birds; 8 genera had declined, whereas 3 had increased. The greatest declines occurred in genera associated with habitats that were deeper and farther from shore. Furthermore, most of the genera that declined primarily fed on pelagic prey resources, such as forage fish and mesozooplankton, and few were directly affected by the 1989 Exxon Valdez oil spill. Our observations of synchronous declines are indicative of a shift in pelagic components of PWS food webs. This pattern was correlated with climate variability at time-scales of several years to a decade.

  16. Patterns of distribution, abundance, and change over time in a subarctic marine bird community

    Science.gov (United States)

    Cushing, Daniel; Roby, Daniel D.; Irons, David B.

    2017-01-01

    Over recent decades, marine ecosystems of Prince William Sound (PWS), Alaska, have experienced concurrent effects of natural and anthropogenic perturbations, including variability in the climate system of the northeastern Pacific Ocean. We documented spatial and temporal patterns of variability in the summer marine bird community in relation to habitat and climate variability using boat-based surveys of marine birds conducted during the period 1989–2012. We hypothesized that a major factor structuring marine bird communities in PWS would be proximity to the shoreline, which is theorized to relate to aspects of food web structure. We also hypothesized that shifts in physical ecosystem drivers differentially affected nearshore-benthic and pelagic components of PWS food webs. We evaluated support for our hypotheses using an approach centered on community-level patterns of spatial and temporal variability. We found that an environmental gradient related to water depth and distance from shore was the dominant factor spatially structuring the marine bird community. Responses of marine birds to this onshore-offshore environmental gradient were related to dietary specialization, and separated marine bird taxa by prey type. The primary form of temporal variability over the study period was monotonic increases or decreases in abundance for 11 of 18 evaluated genera of marine birds; 8 genera had declined, whereas 3 had increased. The greatest declines occurred in genera associated with habitats that were deeper and farther from shore. Furthermore, most of the genera that declined primarily fed on pelagic prey resources, such as forage fish and mesozooplankton, and few were directly affected by the 1989 Exxon Valdez oil spill. Our observations of synchronous declines are indicative of a shift in pelagic components of PWS food webs. This pattern was correlated with climate variability at time-scales of several years to a decade.

  17. Viruses in the marine environment: community dynamics, phage-host interactions and genomic structure

    OpenAIRE

    Lara de la Casa, Elena

    2014-01-01

    There are an estimated 1030 viruses in the world oceans, the majority of which are phages (viruses that infect bacteria). Extensive research has demonstrated the significant influence of marine phages on microbial abundance, community structure, genetic exchange and global biogeochemical cycles. In this thesis, we contribute to increase the knowledge about the ecological role of viruses in marine systems, but also we aimed to provide a better understanding about the interactions between phage...

  18. Status of Coral Reef Fish Communities within the Mombasa Marine ...

    African Journals Online (AJOL)

    The abundance, trophic composition and diversity of fish were investigated in the Mombasa Marine Protected Area (MPA) on the Kenya coast over a period of four years (2004-2007) sixteen years after its establishment to determine its effectiveness. Fish monitoring data collected using belt transects revealed significant ...

  19. Local Stakeholder Perception on Community Participation in Marine Protected Area Management: A Q-Method Approach

    Science.gov (United States)

    Megat Jamual Fawaeed, P. S.; Daim, M. S.

    2018-02-01

    Local stakeholder involvement in Marine Protected Area (MPA) management can bring to a successful MPA. Generally, participatory research in marine protected area management is exploring the relationship between marine protected area management approach adopted by the management agencies and the level of participation of local stakeholder whom reside within the marine protected areas. However, the scenario of local community participation in MPA management in Malaysia seems discouraging and does not align with the International Aichi Biodiversity Target 2020. In order to achieve the International Aichi Biodiversity Target 2020, this paper attempts to explore the methodology on participatory research towards the local stakeholder of Pulau Perhentian Marine Park (PPMP), Terengganu, Malaysia. A Q-methodology is used to investigate the perspective of local stakeholder who represents different stances on the issues, by having participants rank and sort a series of statements by comply quantitative and qualitative method in collecting the data. A structured questionnaire will be employed across this study by means of face-to-face interview. In total, 210 respondents from Kampung Pasir Hantu are randomly selected. Meanwhile, a workshop with the agency (Department of Marine Park) had been held to discuss about the issues faces on behalf of management that manage the PPMP. Using the Q-method, researcher acknowledged wise viewpoints, reflecting how different stakeholders’ perception and opinion about community participation with highlights the current level of community participation in MPA. Thus, this paper describes the phases involved in this study, methodology and analysis used in making a conclusion .

  20. Contaminants reduce the richness and evenness of marine communities: A review and meta-analysis

    International Nuclear Information System (INIS)

    Johnston, Emma L.; Roberts, David A.

    2009-01-01

    Biodiversity of marine ecosystems is integral to their stability and function and is threatened by anthropogenic processes. We conducted a literature review and meta-analysis of 216 studies to understand the effects of common contaminants upon diversity in various marine communities. The most common diversity measures were species richness, the Shannon-Wiener index (H') and Pielou evenness (J). Largest effect sizes were observed for species richness, which tended to be the most sensitive index. Pollution was associated with marine communities containing fewer species or taxa than their pristine counterparts. Marine habitats did not vary in their susceptibility to contamination, rather a ∼40% reduction in richness occurred across all habitats. No class of contaminant was associated with significantly greater impacts on diversity than any other. Survey studies identified larger effects than laboratory or field experiments. Anthropogenic contamination is strongly associated with reductions in the species richness and evenness of marine habitats. - Contamination substantially reduces the biodiversity of marine communities in all major habitat types and across all major contaminant classes.

  1. Marine wildlife entanglement: Assessing knowledge, attitudes, and relevant behaviour in the Australian community

    International Nuclear Information System (INIS)

    Pearson, Elissa; Mellish, Sarah; Sanders, Ben; Litchfield, Carla

    2014-01-01

    Highlights: • Marine debris and marine wildlife entanglement remains a significant global issue. • We examined awareness of this issue in an Australian community sample. • Findings reveal gaps exist in terms of what entanglement is and the risks posed. • Enhancing community understanding may facilitate greater conservation action. • The ‘Seal the Loop’ initiative provides one potential mechanism for such education. - Abstract: Marine debris remains a global challenge, with significant impacts on wildlife. Despite this, there is a paucity of research examining public understanding about marine wildlife entanglement [MWE], particularly within an Australian context. The present study surveyed two hundred and thirteen participants across three coastal sites to assess familiarity with MWE and the effectiveness of a new community education initiative ‘Seal the Loop’ [STL]. Results revealed attitudes toward marine wildlife were very positive (M 40.5, SD 4.12); however 32% of participants were unable to correctly explain what MWE is and risks to wildlife were under-estimated. STL may be one method to enhance public understanding and engagement-if community familiarity with the program can be increased. For those aware of STL (<13% of the sample at the time of the study), findings revealed this was having a positive impact (e.g. learning something new, changed waste disposal behaviours)

  2. Microalgal bioremediation : Current practices and perspectives

    OpenAIRE

    BISWAJIT RATH

    2011-01-01

    During last two decades, extensive attention has been paid on the management of environmental pollution caused by hazardous materials. A number of methods has been developed for removal of such substances like precipitation, evaporation, ion-exchange etc. However these methods have several disadvantages. This review highlights the alternative biological agent abundantly present in nature i.e Microalgae as a potential sink for removal of such toxic substances from the surrounding. Microalgal b...

  3. Marine macrofossil communities in the uppermost Maastrichtian chalk of Stevns Klint, Denmark

    DEFF Research Database (Denmark)

    Hansen, Thomas; Surlyk, Finn

    2014-01-01

    Three successive marine habitats and their benthic macrofossil communities have been recognised and assessed in the uppermost Maastrichtian chalk of Stevns Klint, Denmark. The mound-bedded lower Sigerslev Member was deposited below the photic zone under the influence of persistent, non-erosive bo......Three successive marine habitats and their benthic macrofossil communities have been recognised and assessed in the uppermost Maastrichtian chalk of Stevns Klint, Denmark. The mound-bedded lower Sigerslev Member was deposited below the photic zone under the influence of persistent, non...

  4. Spectroscopic analyses of chemical adaptation processes within microalgal biomass in response to changing environments

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, Frank, E-mail: fvogt@utk.edu; White, Lauren

    2015-03-31

    Highlights: • Microalgae transform large quantities of inorganics into biomass. • Microalgae interact with their growing environment and adapt their chemical composition. • Sequestration capabilities are dependent on cells’ chemical environments. • We develop a chemometric hard-modeling to describe these chemical adaptation dynamics. • This methodology will enable studies of microalgal compound sequestration. - Abstract: Via photosynthesis, marine phytoplankton transforms large quantities of inorganic compounds into biomass. This has considerable environmental impacts as microalgae contribute for instance to counter-balancing anthropogenic releases of the greenhouse gas CO{sub 2}. On the other hand, high concentrations of nitrogen compounds in an ecosystem can lead to harmful algae blooms. In previous investigations it was found that the chemical composition of microalgal biomass is strongly dependent on the nutrient availability. Therefore, it is expected that algae’s sequestration capabilities and productivity are also determined by the cells’ chemical environments. For investigating this hypothesis, novel analytical methodologies are required which are capable of monitoring live cells exposed to chemically shifting environments followed by chemometric modeling of their chemical adaptation dynamics. FTIR-ATR experiments have been developed for acquiring spectroscopic time series of live Dunaliella parva cultures adapting to different nutrient situations. Comparing experimental data from acclimated cultures to those exposed to a chemically shifted nutrient situation reveals insights in which analyte groups participate in modifications of microalgal biomass and on what time scales. For a chemometric description of these processes, a data model has been deduced which explains the chemical adaptation dynamics explicitly rather than empirically. First results show that this approach is feasible and derives information about the chemical biomass

  5. Spectroscopic analyses of chemical adaptation processes within microalgal biomass in response to changing environments

    International Nuclear Information System (INIS)

    Vogt, Frank; White, Lauren

    2015-01-01

    Highlights: • Microalgae transform large quantities of inorganics into biomass. • Microalgae interact with their growing environment and adapt their chemical composition. • Sequestration capabilities are dependent on cells’ chemical environments. • We develop a chemometric hard-modeling to describe these chemical adaptation dynamics. • This methodology will enable studies of microalgal compound sequestration. - Abstract: Via photosynthesis, marine phytoplankton transforms large quantities of inorganic compounds into biomass. This has considerable environmental impacts as microalgae contribute for instance to counter-balancing anthropogenic releases of the greenhouse gas CO 2 . On the other hand, high concentrations of nitrogen compounds in an ecosystem can lead to harmful algae blooms. In previous investigations it was found that the chemical composition of microalgal biomass is strongly dependent on the nutrient availability. Therefore, it is expected that algae’s sequestration capabilities and productivity are also determined by the cells’ chemical environments. For investigating this hypothesis, novel analytical methodologies are required which are capable of monitoring live cells exposed to chemically shifting environments followed by chemometric modeling of their chemical adaptation dynamics. FTIR-ATR experiments have been developed for acquiring spectroscopic time series of live Dunaliella parva cultures adapting to different nutrient situations. Comparing experimental data from acclimated cultures to those exposed to a chemically shifted nutrient situation reveals insights in which analyte groups participate in modifications of microalgal biomass and on what time scales. For a chemometric description of these processes, a data model has been deduced which explains the chemical adaptation dynamics explicitly rather than empirically. First results show that this approach is feasible and derives information about the chemical biomass adaptations

  6. Microalgal lipids biochemistry and biotechnological perspectives.

    Science.gov (United States)

    Bellou, Stamatia; Baeshen, Mohammed N; Elazzazy, Ahmed M; Aggeli, Dimitra; Sayegh, Fotoon; Aggelis, George

    2014-12-01

    In the last few years, there has been an intense interest in using microalgal lipids in food, chemical and pharmaceutical industries and cosmetology, while a noteworthy research has been performed focusing on all aspects of microalgal lipid production. This includes basic research on the pathways of solar energy conversion and on lipid biosynthesis and catabolism, and applied research dealing with the various biological and technical bottlenecks of the lipid production process. In here, we review the current knowledge in microalgal lipids with respect to their metabolism and various biotechnological applications, and we discuss potential future perspectives. The committing step in fatty acid biosynthesis is the carboxylation of acetyl-CoA to form malonyl-CoA that is then introduced in the fatty acid synthesis cycle leading to the formation of palmitic and stearic acids. Oleic acid may also be synthesized after stearic acid desaturation while further conversions of the fatty acids (i.e. desaturations, elongations) occur after their esterification with structural lipids of both plastids and the endoplasmic reticulum. The aliphatic chains are also used as building blocks for structuring storage acylglycerols via the Kennedy pathway. Current research, aiming to enhance lipogenesis in the microalgal cell, is focusing on over-expressing key-enzymes involved in the earlier steps of the pathway of fatty acid synthesis. A complementary plan would be the repression of lipid catabolism by down-regulating acylglycerol hydrolysis and/or β-oxidation. The tendency of oleaginous microalgae to synthesize, apart from lipids, significant amounts of other energy-rich compounds such as sugars, in processes competitive to lipogenesis, deserves attention since the lipid yield may be considerably increased by blocking competitive metabolic pathways. The majority of microalgal production occurs in outdoor cultivation and for this reason biotechnological applications face some difficulties

  7. Marine and giant viruses as indicators of a marine microbial community in a riverine system

    OpenAIRE

    Dann, Lisa M.; Rosales, Stephanie; McKerral, Jody; Paterson, James S.; Smith, Renee J.; Jeffries, Thomas C.; Oliver, Rod L.; Mitchell, James G.

    2016-01-01

    Abstract Viral communities are important for ecosystem function as they are involved in critical biogeochemical cycles and controlling host abundance. This study investigates riverine viral communities around a small rural town that influences local water inputs. Myoviridae, Siphoviridae, Phycodnaviridae, Mimiviridae, Herpesviridae, and Podoviridae were the most abundant families. Viral species upstream and downstream of the town were similar, with Synechoccocus phage, salinus, Prochlorococcu...

  8. The Role of Perceptions for Community-Based Marine Resource Management

    Directory of Open Access Journals (Sweden)

    Katharina Beyerl

    2016-11-01

    Full Text Available Every community-based marine resource management (CBMRM inherently takes place in a highly complex social-ecological environment, and stakeholder perceptions related to various aspects of the natural and social environment guide behavior in every stage of the management process. This paper provides an introduction to the psychology of perception with regard to marine resource management. In particular, it offers a typology of CBMRM relevant perceptions along with an analysis of psychological, societal, and physical factors that modulate them. Based on this analysis, we propose the introduction of specially trained local Perception Experts (PE’s, whose role will be to recognize and reflect individual perceptions of involved stakeholders, and to communicate them at community meetings where decisions are made. This empirically testable addition to current CBMRM schemes could help to increase participation, develop management measures that fit the capacities of the involved stakeholders more accurately, and hence, contribute to a faster rehabilitation of marine resources.

  9. Structure of macroalgal communities on tropical rocky shores inside and outside a marine protected area.

    Science.gov (United States)

    Portugal, Adriana Brizon; Carvalho, Fabrício Lopes; Soares, Marcelo de Oliveira; Horta, Paulo Antunes; de Castro Nunes, José Marcos

    2017-09-01

    The structure of marine macroalgal communities and morpho-functional groups were investigated in a poorly characterized region on the Tropical Southwestern Atlantic coast, Brazil. The survey was conducted at six rocky shores located on the mainland and on coastal islands distributed inside a marine protected area (MPA) and outside the MPA (near a densely populated area). We hypothesized that tropical rocky shores inside the MPA and islands have higher species richness, diversity, and evenness of marine macroalgae. Results confirmed that species richness, diversity and evenness were significantly higher inside the MPA than in rocky shores outside the MPA. Only species richness was higher on islands than on the mainland. The results suggest that human impacts could lead to a competitive advantage and dominance in the articulated calcareous morphotype, resulting in community differences and lower benthic biodiversity in tropical ecosystems near urbanized sites. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. A Mosaic of Geothermal and Marine Features Shapes Microbial Community Structure on Deception Island Volcano, Antarctica

    OpenAIRE

    Amanda G. Bendia; Camila N. Signori; Diego C. Franco; Rubens T. D. Duarte; Brendan J. M. Bohannan; Vivian H. Pellizari

    2018-01-01

    Active volcanoes in Antarctica contrast with their predominantly cold surroundings, resulting in environmental conditions capable of selecting for versatile and extremely diverse microbial communities. This is especially true on Deception Island, where geothermal, marine, and polar environments combine to create an extraordinary range of environmental conditions. Our main goal in this study was to understand how microbial community structure is shaped by gradients of temperature, salinity, an...

  11. Challenges facing local communities in Tanzania in realising locally-managed marine areas

    NARCIS (Netherlands)

    Katikiro, R.E.; Macusi, E.D.; Ashoka Deepananda, K.H.M.

    2015-01-01

    This study explores how the history and process of establishing a marine protected area (MPA) under the control of the state has led to limited interest in community-based management amongst local stakeholders. The study contributes to the understanding of historical events that have discouraged

  12. The Power of Computer-aided Tomography to Investigate Marine Benthic Communities

    Science.gov (United States)

    Utilization of Computer-aided-Tomography (CT) technology is a powerful tool to investigate benthic communities in aquatic systems. In this presentation, we will attempt to summarize our 15 years of experience in developing specific CT methods and applications to marine benthic co...

  13. Competition and facilitation between the marine nitrogen-fixing cyanobacterium Cyanothece and its associated bacterial community

    NARCIS (Netherlands)

    Brauer, Verena S; Stomp, Maayke; Bouvier, Thierry; Fouilland, Eric; Leboulanger, Christophe; Confurius-Guns, Veronique; Weissing, Franz J; Stal, Lucas J; Huisman, Jef

    2015-01-01

    N2-fixing cyanobacteria represent a major source of new nitrogen and carbon for marine microbial communities, but little is known about their ecological interactions with associated microbiota. In this study we investigated the interactions between the unicellular N2-fixing cyanobacterium Cyanothece

  14. Ecological succession reveals potential signatures of marine-terrestrial transition in salt marsh fungal communities

    NARCIS (Netherlands)

    Dini-Andreote, Francisco; Pylro, Victor Satler; Baldrian, Petr; van Elsas, Jan Dirk; Salles, Joana Falcão

    Marine-to-terrestrial transition represents one of the most fundamental shifts in microbial life. Understanding the distribution and drivers of soil microbial communities across coastal ecosystems is critical given the roles of microbes in soil biogeochemistry and their multifaceted influence on

  15. Comparisons of the fungal and protistan communities among different marine sponge holobionts by pyrosequencing.

    Science.gov (United States)

    He, Liming; Liu, Fang; Karuppiah, Valliappan; Ren, Yi; Li, Zhiyong

    2014-05-01

    To date, the knowledge of eukaryotic communities associated with sponges remains limited compared with prokaryotic communities. In a manner similar to prokaryotes, it could be hypothesized that sponge holobionts have phylogenetically diverse eukaryotic symbionts, and the eukaryotic community structures in different sponge holobionts were probably different. In order to test this hypothesis, the communities of eukaryota associated with 11 species of South China Sea sponges were compared with the V4 region of 18S ribosomal ribonucleic acid gene using 454 pyrosequencing. Consequently, 135 and 721 unique operational taxonomic units (OTUs) of fungi and protists were obtained at 97 % sequence similarity, respectively. These sequences were assigned to 2 phyla of fungi (Ascomycota and Basidiomycota) and 9 phyla of protists including 5 algal phyla (Chlorophyta, Haptophyta, Streptophyta, Rhodophyta, and Stramenopiles) and 4 protozoal phyla (Alveolata, Cercozoa, Haplosporidia, and Radiolaria) including 47 orders (12 fungi, 35 protists). Entorrhizales of fungi and 18 orders of protists were detected in marine sponges for the first time. Particularly, Tilletiales of fungi and Chlorocystidales of protists were detected for the first time in marine habitats. Though Ascomycota, Alveolata, and Radiolaria were detected in all the 11 sponge species, sponge holobionts have different fungi and protistan communities according to OTU comparison and principal component analysis at the order level. This study provided the first insights into the fungal and protistan communities associated with different marine sponge holobionts using pyrosequencing, thus further extending the knowledge on sponge-associated eukaryotic diversity.

  16. Effects of organic pollution on biological communities of marine biofilm on hard substrata

    International Nuclear Information System (INIS)

    Sanz-Lázaro, C.; Fodelianakis, S.; Guerrero-Meseguer, L.; Marín, A.; Karakassis, I.

    2015-01-01

    We examined the effect of organic enrichment on diatom and bacterial assemblages of marine epilithic biofilms on two locations in the Mediterranean, one situated in Spain and the other in Greece. Total organic carbon, total organic nitrogen, stable isotopes (δ 13 C and δ 15 N) and chlorophyll a indicated significant incorporation of organic wastes, increased primary production and trophic niche modifications on the biofilms close to the organic enrichment source. In Spain, where the organic load was higher than in Greece, diatom and, to some extent, bacterial assemblages varied following the organic enrichment gradient. The taxonomic richness of diatom and bacterial communities was not influenced by organic enrichment. Classical community parameters showed consistent patterns to organic pollution in both locations, whereas community assemblages were only influenced when organic pollution was greatest. The successional patterns of these communities were similar to other epilithic communities. The modification of community assemblages induced by organic pollution may affect ecological functions. - Highlights: • We examined the effect of organic enrichment on assemblages of marine biofilms. • Classical community parameters showed consistent patterns to organic pollution. • Diatom and bacterial assemblages were affected under high level of organic enrichment. • Successional patterns were similar to other communities inhabiting hard substrata. • Assemblage modifications induced by organic pollution may affect ecological functions. - Organic pollution modifies the assemblages of biofilm communities which may affect important ecological functions

  17. Global change and marine communities: Alien species and climate change

    International Nuclear Information System (INIS)

    Occhipinti-Ambrogi, Anna

    2007-01-01

    Anthropogenic influences on the biosphere since the advent of the industrial age are increasingly causing global changes. Climatic change and the rising concentration of greenhouse gases in the atmosphere are ranking high in scientific and public agendas, and other components of global change are also frequently addressed, among which are the introductions of non indigenous species (NIS) in biogeographic regions well separated from the donor region, often followed by spectacular invasions. In the marine environment, both climatic change and spread of alien species have been studied extensively; this review is aimed at examining the main responses of ecosystems to climatic change, taking into account the increasing importance of biological invasions. Some general principles on NIS introductions in the marine environment are recalled, such as the importance of propagule pressure and of development stages during the time course of an invasion. Climatic change is known to affect many ecological properties; it interacts also with NIS in many possible ways. Direct (proximate) effects on individuals and populations of altered physical-chemical conditions are distinguished from indirect effects on emergent properties (species distribution, diversity, and production). Climatically driven changes may affect both local dispersal mechanisms, due to the alteration of current patterns, and competitive interactions between NIS and native species, due to the onset of new thermal optima and/or different carbonate chemistry. As well as latitudinal range expansions of species correlated with changing temperature conditions, and effects on species richness and the correlated extinction of native species, some invasions may provoke multiple effects which involve overall ecosystem functioning (material flow between trophic groups, primary production, relative extent of organic material decomposition, extent of benthic-pelagic coupling). Some examples are given, including a special

  18. Cascading effects of mass mortality events in Arctic marine communities.

    Science.gov (United States)

    Langangen, Øystein; Ohlberger, Jan; Stige, Leif C; Durant, Joël M; Ravagnan, Elisa; Stenseth, Nils C; Hjermann, Dag Ø

    2017-01-01

    Mass mortality events caused by pulse anthropogenic or environmental perturbations (e.g., extreme weather, toxic spills or epizootics) severely reduce the abundance of a population in a short time. The frequency and impact of these events are likely to increase across the globe. Studies on how such events may affect ecological communities of interacting species are scarce. By combining a multispecies Gompertz model with a Bayesian state-space framework, we quantify community-level effects of a mass mortality event in a single species. We present a case study on a community of fish and zooplankton in the Barents Sea to illustrate how a mass mortality event of different intensities affecting the lower trophic level (krill) may propagate to higher trophic levels (capelin and cod). This approach is especially valuable for assessing community-level effects of potential anthropogenic-driven mass mortality events, owing to the ability to account for uncertainty in the assessed impact due to uncertainty about the ecological dynamics. We hence quantify how the assessed impact of a mass mortality event depends on the degree of precaution considered. We suggest that this approach can be useful for assessing the possible detrimental outcomes of toxic spills, for example oil spills, in relatively simple communities such as often found in the Arctic, a region under increasing influence of human activities due to increased land and sea use. © 2016 John Wiley & Sons Ltd.

  19. Unexpected associated microalgal diversity in the lichen Ramalina farinacea is uncovered by pyrosequencing analyses.

    Directory of Open Access Journals (Sweden)

    Patricia Moya

    Full Text Available The current literature reveals that the intrathalline coexistence of multiple microalgal taxa in lichens is more common than previously thought, and additional complexity is supported by the coexistence of bacteria and basidiomycete yeasts in lichen thalli. This replaces the old paradigm that lichen symbiosis occurs between a fungus and a single photobiont. The lichen Ramalina farinacea has proven to be a suitable model to study the multiplicity of microalgae in lichen thalli due to the constant coexistence of Trebouxia sp. TR9 and T. jamesii in long-distance populations. To date, studies involving phycobiont diversity within entire thalli are based on Sanger sequencing, but this method seems to underestimate the diversity. Here, we aim to analyze both the microalgal diversity and its community structure in a single thallus of the lichen R. farinacea by applying a 454 pyrosequencing approach coupled with a careful ad hoc-performed protocol for lichen sample processing prior to DNA extraction. To ascertain the reliability of the pyrosequencing results and the applied bioinformatics pipeline results, the thalli were divided into three sections (apical, middle and basal zones, and a mock community sample was used. The developed methodology allowed 40448 filtered algal reads to be obtained from a single lichen thallus, which encompassed 31 OTUs representative of different microalgae genera. In addition to corroborating the coexistence of the two Trebouxia sp. TR9 and T. jamesii taxa in the same thallus, this study showed a much higher microalgal diversity associated with the lichen. Along the thallus ramifications, we also detected variations in phycobiont distribution that might correlate with different microenvironmental conditions. These results highlight R. farinacea as a suitable material for studying microalgal diversity and further strengthen the concept of lichens as multispecies microecosystems. Future analyses will be relevant to

  20. Partitioning of organic production in marine plankton communities

    DEFF Research Database (Denmark)

    Conan, P.; Søndergaard, Morten; Kragh, T.

    2007-01-01

    We investigated the partitioning of carbon, nitrogen, and phosphorus between particulate and dissolved production using 11-m(3) marine mesocosms (bags) in a Norwegian fjord with a salinity of 28.3, a chlorophyll concentration of 0.6 mu g L-1, an even biomass among five algal groups, and nitrogen...... between 17 and 58 in the P-replete bags. The C: P ratio of new DOM in the +Si bags was about 300 at all dosing regimes. Consequently, the range in N: P ratios was also large, with values from below 1 to about 30. Carbon-rich DOM in oceans and coastal waters is not necessarily a function of a slow...

  1. Marine protected areas increase temporal stability of community structure, but not density or diversity, of tropical seagrass fish communities.

    Directory of Open Access Journals (Sweden)

    Elisa Alonso Aller

    Full Text Available Marine protected areas (MPAs have been shown to increase long-term temporal stability of fish communities and enhance ecosystem resilience to anthropogenic disturbance. Yet, the potential ability of MPAs to buffer effects of environmental variability at shorter time scales remains widely unknown. In the tropics, the yearly monsoon cycle is a major natural force affecting marine organisms in tropical regions, and its timing and severity are predicted to change over the coming century, with potentially severe effects on marine organisms, ecosystems and ecosystem services. Here, we assessed the ability of MPAs to buffer effects of monsoon seasonality on seagrass-associated fish communities, using a field survey in two MPAs (no-take zones and two unprotected (open-access sites around Zanzibar (Tanzania. We assessed the temporal stability of fish density and community structure within and outside MPAs during three monsoon seasons in 2014-2015, and investigated several possible mechanisms that could regulate temporal stability. Our results show that MPAs did not affect fish density and diversity, but that juvenile fish densities were temporally more stable within MPAs. Second, fish community structure was more stable within MPAs for juvenile and adult fish, but not for subadult fish or the total fish community. Third, the observed effects may be due to a combination of direct and indirect (seagrass-mediated effects of seasonality and, potentially, fluctuating fishing pressure outside MPAs. In summary, these MPAs may not have the ability to enhance fish density and diversity and to buffer effects of monsoon seasonality on the whole fish community. However, they may increase the temporal stability of certain groups, such as juvenile fish. Consequently, our results question whether MPAs play a general role in the maintenance of biodiversity and ecosystem functioning under changing environmental conditions in tropical seagrass fish communities.

  2. Abiotic characteristics and microalgal dynamics in South Africa's largest estuarine lake during a wet to dry transitional phase

    Science.gov (United States)

    Nunes, Monique; Adams, Janine B.; Bate, Guy C.; Bornman, Thomas G.

    2017-11-01

    The summer of 2012/2013 signified the end of the dry phase in the St Lucia estuarine system that lasted for over a decade. The increased rainfall coupled with the partial re-connection of the Mfolozi River to the estuarine system shifted St Lucia to a new limnetic state. With the increased availability of habitat due to the higher water level, it was expected that microalgal biomass and abundance would rapidly increase through recruitment from refuge areas i.e. South Lake and new introductions. Microalgal and physico-chemical data were collected at three sites within the Mfolozi/Msunduzi River and at 23 sites within the St Lucia estuarine system between June 2014 and February 2015. Results from this study indicated low biomass for both phytoplankton (<5 μg l-1) and microphytobenthos (<60 mg m-2) because of local and external drivers. These included limited nutrient and light availability, variable water residence times, biomass dilution and heterogeneity of the sediment. The high spatio-temporal variability limits the effectiveness of using the microalgal communities to detect change in the estuarine lake. In addition, significant intrasystem differences were observed between the three main lake basins and Narrows, due to the influence of the freshwater input from the Mfolozi River. This study provides insight into the spatio-temporal variability of physico-chemical conditions and microalgal communities during the 2014-2015 limnetic state.

  3. Liquefied natural gas production at Hammerfest: A transforming marine community

    NARCIS (Netherlands)

    Bets, van L.K.J.; Tatenhove, van J.P.M.; Mol, A.P.J.

    2016-01-01

    Global energy demand and scarce petroleum resources require communities to adapt to a rapidly changing Arctic environment, but as well to a transforming socio-economic environment instigated by oil and gas development. This is illustrated by liquefied natural gas production by Statoil at Hammerfest,

  4. Predicting the effects of climate change on marine communities and the consequences for fisheries

    DEFF Research Database (Denmark)

    Jennings, Simon; Brander, Keith

    2010-01-01

    for the community under the same climate scenario. The main weakness of the community approach is that the methods predict abundance and production by size-class rather than taxonomic group, and society would be particularly concerned if climate driven changes had a strong effect on the relative production...... of fishable and non-fishable species in the community. The main strength of the community approach is that it provides widely applicable ‘null’ models for assessing the biological effects of climate change and a baseline for model comparisons.......Climate effects on the structure and function of marine communities have received scant attention. The few existing approaches for predicting climate effects suggest that community responses might be predicted from the responses of component populations. These approaches require a very complex...

  5. Patterns and drivers of fish community assembly in a large marine ecosystem

    DEFF Research Database (Denmark)

    Pécuchet, Lauréne; Törnroos, Anna; Lindegren, Martin

    2016-01-01

    . To determine assembly rules, ecological similarities of co-occurring species are often investigated. This can be evaluated using trait-based indices summarizing the species’ niches in a given community. In order to investigate the underlying processes shaping community assembly in marine ecosystems, we...... investigated the patterns and drivers of fish community composition in the Baltic Sea, a semi-enclosed sea characterized by a pronounced environmental gradient. Our results showed a marked decline in species- and functional richness, largely explained by decreasing salinities. In addition, habitat complexity...

  6. Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton▿

    Science.gov (United States)

    Eriksson, K. M.; Clarke, A. K.; Franzen, L.-G.; Kuylenstierna, M.; Martinez, K.; Blanck, H.

    2009-01-01

    This study analyzes psbA gene sequences, predicted D1 protein sequences, species relative abundance, and pollution-induced community tolerance in marine periphyton communities exposed to the antifouling compound Irgarol 1051. The mechanism of action of Irgarol is the inhibition of photosynthetic electron transport at photosystem II by binding to the D1 protein. The metagenome of the communities was used to produce clone libraries containing fragments of the psbA gene encoding the D1 protein. Community tolerance was quantified with a short-term test for the inhibition of photosynthesis. The communities were established in a continuous flow of natural seawater through microcosms with or without added Irgarol. The selection pressure from Irgarol resulted in an altered species composition and an inducted community tolerance to Irgarol. Moreover, there was a very high diversity in the psbA gene sequences in the periphyton, and the composition of psbA and D1 fragments within the communities was dramatically altered by increased Irgarol exposure. Even though tolerance to this type of compound in land plants often depends on a single amino acid substitution (Ser264→Gly) in the D1 protein, this was not the case for marine periphyton species. Instead, the tolerance mechanism likely involves increased degradation of D1. When we compared sequences from low and high Irgarol exposure, differences in nonconserved amino acids were found only in the so-called PEST region of D1, which is involved in regulating its degradation. Our results suggest that environmental contamination with Irgarol has led to selection for high-turnover D1 proteins in marine periphyton communities at the west coast of Sweden. PMID:19088321

  7. Bioavailability of autochthonous dissolved organic nitrogen in marine plankton communities

    DEFF Research Database (Denmark)

    Knudsen, Helle; Markager, Svend Stiig; Søndergaard, Morten

    The purpose of this study was to investigate the bioavailability of dissolved organic nitrogen (DON) produced during a phytoplankton bloom. The experiments were conducted with natural plankton communities as batch growth experiments over approximately 30 days with nitrogen limitation. Five to six...... times during the exponential and stationary phases of each experimental bloom the bioavailability of DON was measured over 60 days together with DOC and oxygen consumption. The overall aim was to quantify remineralization of the added nitrate. The results showed that maximum 33 % of the added nitrate...

  8. Microalgal cell disruption via ultrasonic nozzle spraying.

    Science.gov (United States)

    Wang, M; Yuan, W

    2015-01-01

    The objective of this study was to understand the effect of operating parameters, including ultrasound amplitude, spraying pressure, nozzle orifice diameter, and initial cell concentration on microalgal cell disruption and lipid extraction in an ultrasonic nozzle spraying system (UNSS). Two algal species including Scenedesmus dimorphus and Nannochloropsis oculata were evaluated. Experimental results demonstrated that the UNSS was effective in the disruption of microalgal cells indicated by significant changes in cell concentration and Nile red-stained lipid fluorescence density between all treatments and the control. It was found that increasing ultrasound amplitude generally enhanced cell disruption and lipid recovery although excessive input energy was not necessary for best results. The effect of spraying pressure and nozzle orifice diameter on cell disruption and lipid recovery was believed to be dependent on the competition between ultrasound-induced cavitation and spraying-generated shear forces. Optimal cell disruption was not always achieved at the highest spraying pressure or biggest nozzle orifice diameter; instead, they appeared at moderate levels depending on the algal strain and specific settings. Increasing initial algal cell concentration significantly reduced cell disruption efficiency. In all UNSS treatments, the effectiveness of cell disruption and lipid recovery was found to be dependent on the algal species treated.

  9. A Mosaic of Geothermal and Marine Features Shapes Microbial Community Structure on Deception Island Volcano, Antarctica

    Directory of Open Access Journals (Sweden)

    Amanda G. Bendia

    2018-05-01

    Full Text Available Active volcanoes in Antarctica contrast with their predominantly cold surroundings, resulting in environmental conditions capable of selecting for versatile and extremely diverse microbial communities. This is especially true on Deception Island, where geothermal, marine, and polar environments combine to create an extraordinary range of environmental conditions. Our main goal in this study was to understand how microbial community structure is shaped by gradients of temperature, salinity, and geochemistry in polar marine volcanoes. Thereby, we collected surface sediment samples associated with fumaroles and glaciers at two sites on Deception, with temperatures ranging from 0 to 98°C. Sequencing of the 16S rRNA gene was performed to assess the composition and diversity of Bacteria and Archaea. Our results revealed that Deception harbors a combination of taxonomic groups commonly found both in cold and geothermal environments of continental Antarctica, and also groups normally identified at deep and shallow-sea hydrothermal vents, such as hyperthermophilic archaea. We observed a clear separation in microbial community structure across environmental gradients, suggesting that microbial community structure is strongly niche driven on Deception. Bacterial community structure was significantly associated with temperature, pH, salinity, and chemical composition; in contrast, archaeal community structure was strongly associated only with temperature. Our work suggests that Deception represents a peculiar “open-air” laboratory to elucidate central questions regarding molecular adaptability, microbial evolution, and biogeography of extremophiles in polar regions.

  10. Assessing the effect of marine reserves on household food security in Kenyan coral reef fishing communities.

    Directory of Open Access Journals (Sweden)

    Emily S Darling

    Full Text Available Measuring the success or failure of natural resource management is a key challenge to evaluate the impact of conservation for ecological, economic and social outcomes. Marine reserves are a popular tool for managing coastal ecosystems and resources yet surprisingly few studies have quantified the social-economic impacts of marine reserves on food security despite the critical importance of this outcome for fisheries management in developing countries. Here, I conducted semi-structured household surveys with 113 women heads-of-households to investigate the influence of two old, well-enforced, no-take marine reserves on food security in four coastal fishing communities in Kenya, East Africa. Multi-model information-theoretic inference and matching methods found that marine reserves did not influence household food security, as measured by protein consumption, diet diversity and food coping strategies. Instead, food security was strongly influenced by fishing livelihoods and household wealth: fishing families and wealthier households were more food secure than non-fishing and poorer households. These findings highlight the importance of complex social and economic landscapes of livelihoods, urbanization, power and gender dynamics that can drive the outcomes of marine conservation and management.

  11. Diversity and community structure of marine microbes around the Benham Rise underwater plateau, northeastern Philippines.

    Science.gov (United States)

    Gajigan, Andrian P; Yñiguez, Aletta T; Villanoy, Cesar L; San Diego-McGlone, Maria Lourdes; Jacinto, Gil S; Conaco, Cecilia

    2018-01-01

    Microbes are central to the structuring and functioning of marine ecosystems. Given the remarkable diversity of the ocean microbiome, uncovering marine microbial taxa remains a fundamental challenge in microbial ecology. However, there has been little effort, thus far, to describe the diversity of marine microorganisms in the region of high marine biodiversity around the Philippines. Here, we present data on the taxonomic diversity of bacteria and archaea in Benham Rise, Philippines, Western Pacific Ocean, using 16S V4 rRNA gene sequencing. The major bacterial and archaeal phyla identified in the Benham Rise are Proteobacteria, Cyanobacteria, Actinobacteria, Bacteroidetes, Marinimicrobia, Thaumarchaeota and, Euryarchaeota. The upper mesopelagic layer exhibited greater microbial diversity and richness compared to surface waters. Vertical zonation of the microbial community is evident and may be attributed to physical stratification of the water column acting as a dispersal barrier. Canonical Correspondence Analysis (CCA) recapitulated previously known associations of taxa and physicochemical parameters in the environment, such as the association of oligotrophic clades with low nutrient surface water and deep water clades that have the capacity to oxidize ammonia or nitrite at the upper mesopelagic layer. These findings provide foundational information on the diversity of marine microbes in Philippine waters. Further studies are warranted to gain a more comprehensive picture of microbial diversity within the region.

  12.  Marine derived dinoflagellates in Antarctic saline lakes: Community composition and annual dynamics

    DEFF Research Database (Denmark)

    Rengefors, K.; Layborn-Parry, L.; Logares, R.

    2008-01-01

    polar dinoflagellate community, and not freshwater species. Polarella glacialis Montresor, Procaccini et Stoecker, a bipolar marine species, was for the first time described in a lake habitat and was an important phototrophic component in the higher salinity lakes. In the brackish lakes, we found a new...... sibling species to the brackish-water species Scrippsiella hangoei (J. Schiller) J. Larsen, previously observed only in the Baltic Sea....

  13. Global learning for local solutions: Reducing vulnerability of marine-dependent coastal communities

    Science.gov (United States)

    Salim, S. S.; Paytan, A.

    2016-12-01

    The project `Global learning for local solutions: Reducing vulnerability of marine-dependent coastal communities' (GULLS) falls within the Belmont Forum and G8 Research Councils Initiative on Multilateral Research Funding. Participants include teams from nine countries: Australia, Brazil, India, Madagascar, Mozambique, New Zealand, South Africa, the United Kingdom and the United States of America. The project focuses on five regional `hotspots' of climate and social change, defined as fast-warming marine areas and areas experiencing social tensions as a result of change: south-east Australia, Brazil, India, South Africa, and the Mozambique Channel and adjacent countries of Mozambique and Madagascar. These areas require most urgent attention and serve as valuable case studies for wider applications. The project aims to assist coastal communities and other stakeholders dependent on marine resources to adapt to climate change and variability through an integrated and trans-disciplinary approach. Combining best available global knowledge with local knowledge and conditions, it is exploring adaptation options and approaches to strengthen resilience at local and community levels, with a focus on options for reconciling the needs for food security with long-term sustainability and conservation. The project will also contribute to capacity development and empowering fishing communities and other fisheries-dependent stakeholders.A standardized vulnerability assessment framework is being developed that will be used to integrate results from natural, social and economic studies in order to identify needs and options for strengthening management and existing policies. Structured comparisons between the hot-spots will assist global efforts for adaptation and strengthening resilience in marine and coastal social-ecological systems.

  14. Spatial and body-size dependent response of marine pelagic communities to projected global climate change.

    Science.gov (United States)

    Lefort, Stelly; Aumont, Olivier; Bopp, Laurent; Arsouze, Thomas; Gehlen, Marion; Maury, Olivier

    2015-01-01

    Temperature, oxygen, and food availability directly affect marine life. Climate models project a global warming of the ocean's surface (~+3 °C), a de-oxygenation of the ocean's interior (~-3%) and a decrease in total marine net primary production (~-8%) under the 'business as usual' climate change scenario (RCP8.5). We estimated the effects of these changes on biological communities using a coupled biogeochemical (PISCES)--ecosystems (APECOSM) model forced by the physical outputs of the last generation of the IPSL-CM Earth System Model. The APECOSM model is a size-structured bio-energetic model that simulates the 3D dynamical distributions of three interactive pelagic communities (epipelagic, mesopelagic, and migratory) under the effects of multiple environmental factors. The PISCES-APECOSM model ran from 1850 to 2100 under historical forcing followed by RCP8.5. Our RCP8.5 simulation highlights significant changes in the spatial distribution, biomass, and maximum body-size of the simulated pelagic communities. Biomass and maximum body-size increase at high latitude over the course of the century, reflecting the capacity of marine organisms to respond to new suitable environment. At low- and midlatitude, biomass and maximum body-size strongly decrease. In those regions, large organisms cannot maintain their high metabolic needs because of limited and declining food availability. This resource reduction enhances the competition and modifies the biomass distribution among and within the three communities: the proportion of small organisms increases in the three communities and the migrant community that initially comprised a higher proportion of small organisms is favored. The greater resilience of small body-size organisms resides in their capacity to fulfill their metabolic needs under reduced energy supply and is further favored by the release of predation pressure due to the decline of large organisms. These results suggest that small body-size organisms might be

  15. Effects of exotic fish farms on bird communities in lake and marine ecosystems

    Science.gov (United States)

    Jiménez, Jaime E.; Arriagada, Aldo M.; Fontúrbel, Francisco E.; Camus, Patricio A.; Ávila-Thieme, M. Isidora

    2013-08-01

    Salmon farming is a widespread activity around the world, also known to promote diverse environmental effects on aquatic ecosystems. However, information regarding the impact of salmon farming on bird assemblages is notably scarce. We hypothesize that salmon farming, by providing food subsidies and physical structures to birds, will change their local community structure. To test this hypothesis, we conducted a seasonal monitoring of bird richness, abundance, and composition at paired salmon pen and control plots in two marine and two lake sites in southern Chile, from fall 2002 to summer 2004. Overall, salmon farming had no significant effects on species richness, but bird abundance was significantly and noticeably higher in salmon pens than in controls. Such aggregation was mainly accounted for by the trophic guilds of omnivores, diving piscivores, carrion eaters, and perching piscivores, but not by invertebrate feeders, herbivores, and surface feeders. Species composition was also significantly and persistently different between salmon pens and controls within each lake or marine locality. The patterns described above remained consistent across environment types and seasons indicating that salmon farming is changing the community structure of birds in both lake and marine habitats by promoting functional and aggregation responses, particularly by favoring species with broader niches. Such local patterns may thus anticipate potential threats from the ongoing expansion of the salmon industry to neighboring areas in Chile, resulting in regional changes of bird communities, toward a less diverse one and dominated by opportunistic, common, and generalist species such as gulls, vultures, and cormorants.

  16. Molecular Techniques Revealed Highly Diverse Microbial Communities in Natural Marine Biofilms on Polystyrene Dishes for Invertebrate Larval Settlement

    KAUST Repository

    Lee, On On; Chung, Hong Chun; Yang, Jiangke; Wang, Yong; Dash, Swagatika; Wang, Hao; Qian, Pei-Yuan

    2014-01-01

    Biofilm microbial communities play an important role in the larval settlement response of marine invertebrates. However, the underlying mechanism has yet to be resolved, mainly because of the uncertainties in characterizing members

  17. Biodiversity of marine communities in Pearl Harbor, Oahu, Hawaii with observations in 1996 on introduced exotic species (NODC Accession 0000330)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The marine and estuarine invertebrate and fish communities in Pearl Harbor, Oahu, Hawaii were surveyed between January and October, 1996. Samples were taken and...

  18. Dispersal similarly shapes both population genetics and community patterns in the marine realm

    KAUST Repository

    Chust, Guillem

    2016-06-27

    Dispersal plays a key role to connect populations and, if limited, is one of the main processes to maintain and generate regional biodiversity. According to neutral theories of molecular evolution and biodiversity, dispersal limitation of propagules and population stochasticity are integral to shaping both genetic and community structure. We conducted a parallel analysis of biological connectivity at genetic and community levels in marine groups with different dispersal traits. We compiled large data sets of population genetic structure (98 benthic macroinvertebrate and 35 planktonic species) and biogeographic data (2193 benthic macroinvertebrate and 734 planktonic species). We estimated dispersal distances from population genetic data (i.e., FST vs. geographic distance) and from β-diversity at the community level. Dispersal distances ranked the biological groups in the same order at both genetic and community levels, as predicted by organism dispersal ability and seascape connectivity: macrozoobenthic species without dispersing larvae, followed by macrozoobenthic species with dispersing larvae and plankton (phyto- and zooplankton). This ranking order is associated with constraints to the movement of macrozoobenthos within the seabed compared with the pelagic habitat. We showed that dispersal limitation similarly determines the connectivity degree of communities and populations, supporting the predictions of neutral theories in marine biodiversity patterns.

  19. Dispersal similarly shapes both population genetics and community patterns in the marine realm

    Science.gov (United States)

    Chust, Guillem; Villarino, Ernesto; Chenuil, Anne; Irigoien, Xabier; Bizsel, Nihayet; Bode, Antonio; Broms, Cecilie; Claus, Simon; Fernández de Puelles, María L.; Fonda-Umani, Serena; Hoarau, Galice; Mazzocchi, Maria G.; Mozetič, Patricija; Vandepitte, Leen; Veríssimo, Helena; Zervoudaki, Soultana; Borja, Angel

    2016-06-01

    Dispersal plays a key role to connect populations and, if limited, is one of the main processes to maintain and generate regional biodiversity. According to neutral theories of molecular evolution and biodiversity, dispersal limitation of propagules and population stochasticity are integral to shaping both genetic and community structure. We conducted a parallel analysis of biological connectivity at genetic and community levels in marine groups with different dispersal traits. We compiled large data sets of population genetic structure (98 benthic macroinvertebrate and 35 planktonic species) and biogeographic data (2193 benthic macroinvertebrate and 734 planktonic species). We estimated dispersal distances from population genetic data (i.e., FST vs. geographic distance) and from β-diversity at the community level. Dispersal distances ranked the biological groups in the same order at both genetic and community levels, as predicted by organism dispersal ability and seascape connectivity: macrozoobenthic species without dispersing larvae, followed by macrozoobenthic species with dispersing larvae and plankton (phyto- and zooplankton). This ranking order is associated with constraints to the movement of macrozoobenthos within the seabed compared with the pelagic habitat. We showed that dispersal limitation similarly determines the connectivity degree of communities and populations, supporting the predictions of neutral theories in marine biodiversity patterns.

  20. Marine bioinvasions: Differences in tropical copepod communities between inside and outside a port

    Science.gov (United States)

    Soares, Marcelo de Oliveira; Campos, Carolina Coelho; Santos, Nívia Maria Oliveira; Barroso, Hortência de Sousa; Mota, Erika Maria Targino; Menezes, Maria Ozilea Bezerra de; Rossi, Sergio; Garcia, Tatiane Martins

    2018-04-01

    The difficulty of detecting non-indigenous species (NIS) in marine environments is an "invisible problem" in areas where plankton monitoring does not occur. In this study, we investigated the dominance of the NIS Temora turbinata and copepod community structure in two tropical marine habitats: inside an offshore port, which had turbid and calm waters, and outside the port, which was more hydrodynamic. Our study area was on the northeast coast of Brazil. We found 17 taxa of Copepoda, which were dominated by T. turbinata and the congener, T. stylifera. The high average density of the NIS (21.03 ind./m3) was in stark contrast with that of the native copepods (0.01-3.27 ind./m3). The NIS density was negatively correlated with the species richness and evenness of the native community, was significantly higher inside the port than outside, and was positively correlated with phytoplankton density. A multivariate analysis revealed that there was a significant difference in copepod community structure between inside and outside the port; outside the port, the community was more diverse, and the native T. stylifera was more abundant. We found that tropical copepod communities inside an offshore port have low diversity, and probably have little biotic resistance against NIS invasions. Our results, combined with those previously obtained, highlight the need to study the spatial distributions of NIS and native species in pelagic environments.

  1. Dispersal similarly shapes both population genetics and community patterns in the marine realm

    KAUST Repository

    Chust, Guillem; Villarino, Ernesto; Chenuil, Anne; Irigoien, Xabier; Bizsel, Nihayet; Bode, Antonio; Broms, Cecilie; Claus, Simon; Ferná ndez de Puelles, Marí a L.; Fonda-Umani, Serena; Hoarau, Galice; Mazzocchi, Maria G.; Mozetič, Patricija; Vandepitte, Leen; Verí ssimo, Helena; Zervoudaki, Soultana; Borja, Angel

    2016-01-01

    Dispersal plays a key role to connect populations and, if limited, is one of the main processes to maintain and generate regional biodiversity. According to neutral theories of molecular evolution and biodiversity, dispersal limitation of propagules and population stochasticity are integral to shaping both genetic and community structure. We conducted a parallel analysis of biological connectivity at genetic and community levels in marine groups with different dispersal traits. We compiled large data sets of population genetic structure (98 benthic macroinvertebrate and 35 planktonic species) and biogeographic data (2193 benthic macroinvertebrate and 734 planktonic species). We estimated dispersal distances from population genetic data (i.e., FST vs. geographic distance) and from β-diversity at the community level. Dispersal distances ranked the biological groups in the same order at both genetic and community levels, as predicted by organism dispersal ability and seascape connectivity: macrozoobenthic species without dispersing larvae, followed by macrozoobenthic species with dispersing larvae and plankton (phyto- and zooplankton). This ranking order is associated with constraints to the movement of macrozoobenthos within the seabed compared with the pelagic habitat. We showed that dispersal limitation similarly determines the connectivity degree of communities and populations, supporting the predictions of neutral theories in marine biodiversity patterns.

  2. Ecological succession reveals potential signatures of marine-terrestrial transition in salt marsh fungal communities.

    Science.gov (United States)

    Dini-Andreote, Francisco; Pylro, Victor Satler; Baldrian, Petr; van Elsas, Jan Dirk; Salles, Joana Falcão

    2016-08-01

    Marine-to-terrestrial transition represents one of the most fundamental shifts in microbial life. Understanding the distribution and drivers of soil microbial communities across coastal ecosystems is critical given the roles of microbes in soil biogeochemistry and their multifaceted influence on landscape succession. Here, we studied the fungal community dynamics in a well-established salt marsh chronosequence that spans over a century of ecosystem development. We focussed on providing high-resolution assessments of community composition, diversity and ecophysiological shifts that yielded patterns of ecological succession through soil formation. Notably, despite containing 10- to 100-fold lower fungal internal transcribed spacer abundances, early-successional sites revealed fungal richnesses comparable to those of more mature soils. These newly formed sites also exhibited significant temporal variations in β-diversity that may be attributed to the highly dynamic nature of the system imposed by the tidal regime. The fungal community compositions and ecophysiological assignments changed substantially along the successional gradient, revealing a clear signature of ecological replacement and gradually transforming the environment from a marine into a terrestrial system. Moreover, distance-based linear modelling revealed soil physical structure and organic matter to be the best predictors of the shifts in fungal β-diversity along the chronosequence. Taken together, our study lays the basis for a better understanding of the spatiotemporally determined fungal community dynamics in salt marshes and highlights their ecophysiological traits and adaptation in an evolving ecosystem.

  3. Cell disruption and lipid extraction for microalgal biorefineries: A review.

    Science.gov (United States)

    Lee, Soo Youn; Cho, Jun Muk; Chang, Yong Keun; Oh, You-Kwan

    2017-11-01

    The microalgae-based biorefinement process has attracted much attention from academic and industrial researchers attracted to its biofuel, food and nutraceutical applications. In this paper, recent developments in cell-disruption and lipid-extraction methods, focusing on four biotechnologically important microalgal species (namely, Chlamydomonas, Haematococcus, Chlorella, and Nannochloropsis spp.), are reviewed. The structural diversity and rigidity of microalgal cell walls complicate the development of efficient downstream processing methods for cell-disruption and subsequent recovery of intracellular lipid and pigment components. Various mechanical, chemical and biological cell-disruption methods are discussed in detail and compared based on microalgal species and status (wet/dried), scale, energy consumption, efficiency, solvent extraction, and synergistic combinations. The challenges and prospects of the downstream processes for the future development of eco-friendly and economical microalgal biorefineries also are outlined herein. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Physico-chemical and biotic factors influencing microalgal seed ...

    African Journals Online (AJOL)

    Physico-chemical and biotic factors influencing microalgal seed culture propagation for inoculation of a ... African Journal of Biotechnology ... used to inoculate an open raceway pond for large scale biomass production for biodiesel production.

  5. Decoding size distribution patterns in marine and transitional water phytoplankton: from community to species level.

    Directory of Open Access Journals (Sweden)

    Leonilde Roselli

    Full Text Available Understanding the mechanisms of phytoplankton community assembly is a fundamental issue of aquatic ecology. Here, we use field data from transitional (e.g. coastal lagoons and coastal water environments to decode patterns of phytoplankton size distribution into organization and adaptive mechanisms. Transitional waters are characterized by higher resource availability and shallower well-mixed water column than coastal marine environments. Differences in physico-chemical regime between the two environments have been hypothesized to exert contrasting selective pressures on phytoplankton cell morphology (size and shape. We tested the hypothesis focusing on resource availability (nutrients and light and mixed layer depth as ecological axes that define ecological niches of phytoplankton. We report fundamental differences in size distributions of marine and freshwater diatoms, with transitional water phytoplankton significantly smaller and with higher surface to volume ratio than marine species. Here, we hypothesize that mixing condition affecting size-dependent sinking may drive phytoplankton size and shape distributions. The interplay between shallow mixed layer depth and frequent and complete mixing of transitional waters may likely increase the competitive advantage of small phytoplankton limiting large cell fitness. The nutrient regime appears to explain the size distribution within both marine and transitional water environments, while it seem does not explain the pattern observed across the two environments. In addition, difference in light availability across the two environments appear do not explain the occurrence of asymmetric size distribution at each hierarchical level. We hypothesize that such competitive equilibria and adaptive strategies in resource exploitation may drive by organism's behavior which exploring patch resources in transitional and marine phytoplankton communities.

  6. Marine fish community structure and habitat associations on the Canadian Beaufort shelf and slope

    Science.gov (United States)

    Majewski, Andrew R.; Atchison, Sheila; MacPhee, Shannon; Eert, Jane; Niemi, Andrea; Michel, Christine; Reist, James D.

    2017-03-01

    Marine fishes in the Canadian Beaufort Sea have complex interactions with habitats and prey, and occupy a pivotal position in the food web by transferring energy between lower- and upper-trophic levels, and also within and among habitats (e.g., benthic-pelagic coupling). The distributions, habitat associations, and community structure of most Beaufort Sea marine fishes, however, are unknown thus precluding effective regulatory management of emerging offshore industries in the region (e.g., hydrocarbon development, shipping, and fisheries). Between 2012 and 2014, Fisheries and Oceans Canada conducted the first baseline survey of offshore marine fishes, their habitats, and ecological relationships in the Canadian Beaufort Sea. Benthic trawling was conducted at 45 stations spanning 18-1001 m depths across shelf and slope habitats. Physical oceanographic variables (depth, salinity, temperature, oxygen), biological variables (benthic chlorophyll and integrated water-column chlorophyll) and sediment composition (grain size) were assessed as potential explanatory variables for fish community structure using a non-parametric statistical approach. Selected stations were re-sampled in 2013 and 2014 for a preliminary assessment of inter-annual variability in the fish community. Four distinct fish assemblages were delineated on the Canadian Beaufort Shelf and slope: 1) Nearshore-shelf: 50 and ≤200 m depths, 3) Upper-slope: ≥200 and ≤500 m depths, and 4) Lower-slope: ≥500 m depths. Depth was the environmental variable that best explained fish community structure, and each species assemblage was spatially associated with distinct aspects of the vertical water mass profile. Significant differences in the fish community from east to west were not detected, and the species composition of the assemblages on the Canadian Beaufort Shelf have not changed substantially over the past decade. This community analysis provides a framework for testing hypotheses regarding the trophic

  7. Energy aspects of microalgal biodiesel production

    Directory of Open Access Journals (Sweden)

    Edith Martinez-Guerra

    2016-03-01

    Full Text Available Algal biodiesel production will play a significant role in sustaining future transportation fuel supplies. A large number of researchers around the world are investigating into making this process sustainable by increasing the energy gains and by optimizing resource-utilization efficiencies. Although, research is being pursued aggressively in all aspects of algal biodiesel production from microalgal cell cultivation, cell harvesting, and extraction and transesterification steps to the final product separation and purification, there is a large disparity in the data presented in recent reports making it difficult to assess the real potential of microalgae as a future energy source. This article discusses some of the key issues in energy consumption in the process of algal biodiesel production and identifies the areas for improvement to make this process energy-positive and sustainable.

  8. Pole-to-pole biogeography of surface and deep marine bacterial communities

    Science.gov (United States)

    Ghiglione, Jean-François; Galand, Pierre E.; Pommier, Thomas; Pedrós-Alió, Carlos; Maas, Elizabeth W.; Bakker, Kevin; Bertilson, Stefan; Kirchman, David L.; Lovejoy, Connie; Yager, Patricia L.; Murray, Alison E.

    2012-01-01

    The Antarctic and Arctic regions offer a unique opportunity to test factors shaping biogeography of marine microbial communities because these regions are geographically far apart, yet share similar selection pressures. Here, we report a comprehensive comparison of bacterioplankton diversity between polar oceans, using standardized methods for pyrosequencing the V6 region of the small subunit ribosomal (SSU) rRNA gene. Bacterial communities from lower latitude oceans were included, providing a global perspective. A clear difference between Southern and Arctic Ocean surface communities was evident, with 78% of operational taxonomic units (OTUs) unique to the Southern Ocean and 70% unique to the Arctic Ocean. Although polar ocean bacterial communities were more similar to each other than to lower latitude pelagic communities, analyses of depths, seasons, and coastal vs. open waters, the Southern and Arctic Ocean bacterioplankton communities consistently clustered separately from each other. Coastal surface Southern and Arctic Ocean communities were more dissimilar from their respective open ocean communities. In contrast, deep ocean communities differed less between poles and lower latitude deep waters and displayed different diversity patterns compared with the surface. In addition, estimated diversity (Chao1) for surface and deep communities did not correlate significantly with latitude or temperature. Our results suggest differences in environmental conditions at the poles and different selection mechanisms controlling surface and deep ocean community structure and diversity. Surface bacterioplankton may be subjected to more short-term, variable conditions, whereas deep communities appear to be structured by longer water-mass residence time and connectivity through ocean circulation. PMID:23045668

  9. Towards microalgal triglycerides in the commodity markets.

    Science.gov (United States)

    Benvenuti, Giulia; Ruiz, Jesús; Lamers, Packo P; Bosma, Rouke; Wijffels, René H; Barbosa, Maria J

    2017-01-01

    Microalgal triglycerides (TAGs) hold great promise as sustainable feedstock for commodity industries. However, to determine research priorities and support business decisions, solid techno-economic studies are essential. Here, we present a techno-economic analysis of two-step TAG production (growth reactors are operated in continuous mode such that multiple batch-operated stress reactors are inoculated and harvested sequentially) for a 100-ha plant in southern Spain using vertically stacked tubular photobioreactors. The base case is established with outdoor pilot-scale data and based on current process technology. For the base case, production costs of 6.7 € per kg of biomass containing 24% TAG (w/w) were found. Several scenarios with reduced production costs were then presented based on the latest biological and technological advances. For instance, much effort should focus on increasing the photosynthetic efficiency during the stress and growth phases, as this is the most influential parameter on production costs (30 and 14% cost reduction from base case). Next, biological and technological solutions should be implemented for a reduction in cooling requirements (10 and 4.5% cost reduction from base case when active cooling is avoided and cooling setpoint is increased, respectively). When implementing all the suggested improvements, production costs can be decreased to 3.3 € per kg of biomass containing 60% TAG (w/w) within the next 8 years. With our techno-economic analysis, we indicated a roadmap for a substantial cost reduction. However, microalgal TAGs are not yet cost efficient when compared to their present market value. Cost-competiveness strictly relies on the valorization of the whole biomass components and on cheaper PBR designs (e.g. plastic film flat panels). In particular, further research should focus on the development and commercialization of PBRs where active cooling is avoided and stable operating temperatures are maintained by the water

  10. Divergent ecosystem responses within a benthic marine community to ocean acidification.

    Science.gov (United States)

    Kroeker, Kristy J; Micheli, Fiorenza; Gambi, Maria Cristina; Martz, Todd R

    2011-08-30

    Ocean acidification is predicted to impact all areas of the oceans and affect a diversity of marine organisms. However, the diversity of responses among species prevents clear predictions about the impact of acidification at the ecosystem level. Here, we used shallow water CO(2) vents in the Mediterranean Sea as a model system to examine emergent ecosystem responses to ocean acidification in rocky reef communities. We assessed in situ benthic invertebrate communities in three distinct pH zones (ambient, low, and extreme low), which differed in both the mean and variability of seawater pH along a continuous gradient. We found fewer taxa, reduced taxonomic evenness, and lower biomass in the extreme low pH zones. However, the number of individuals did not differ among pH zones, suggesting that there is density compensation through population blooms of small acidification-tolerant taxa. Furthermore, the trophic structure of the invertebrate community shifted to fewer trophic groups and dominance by generalists in extreme low pH, suggesting that there may be a simplification of food webs with ocean acidification. Despite high variation in individual species' responses, our findings indicate that ocean acidification decreases the diversity, biomass, and trophic complexity of benthic marine communities. These results suggest that a loss of biodiversity and ecosystem function is expected under extreme acidification scenarios.

  11. Distribution of the dominant microbial communities in marine sediments containing high concentrations of gas hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, B.; Colwell, F.; Carini, P.; Torres, M. [Oregon State Univ., Corvallis, OR (United States); Hangsterfer, A.; Kastner, M. [California Univ., San Diego, CA (United States). Scripps Inst. of Oceanography; Brodie, E. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Center for Environmental Biotechnology; Daly, R. [California Univ., Berkeley, CA (United States); Holland, M. [GeoTek, Daventry, Northants (United Kingdom); Long, P.; Schaef, H. [Pacific Northwest National Laboratory, Richland, WA (United States). Environmental Technology; Delwiche, M. [Idaho National Laboratory, Idaho Falls, ID (United States). Biotechnology; Winters, W. [United States Geological Survey, Woods Hole, MA (United States). Woods Hole Science Center; Riedel, M. [McGill Univ., Montreal, PQ (Canada). Dept. of Earth and Planetary Sciences

    2008-07-01

    Methane produced by microorganisms represents a large portion of the methane that occurs in marine sediments where gas hydrates are present. The diverse communities that populate these formations have been documented by cultures or through molecular traces. Previous studies have explored the biogeography of hydrate-bearing systems by comparing clone libraries developed from sediments where hydrates are abundant with those developed from sediments that lack hydrates. There is a distinct microbial community present in sediments that have methane hydrates. This paper presented an investigation into finer-scale biogeography, in order to determine how factors such as the presence or absence of hydrates, grain size, and the depositional environment in marine sediments may control the number, type and distribution of microbial communities in sediments. The purpose of the study was to understand the controls on the distribution and activity of all microbes that contribute to the conversion of organic matter to methane. To this aim, DNA was extracted from deep marine sediments cored from continental slope locations including offshore India and the Cascadia Margin. The data from the study was used to refine computational models that require biological rate terms that are consistent with sediment conditions in order to accurately describe the dynamics of this large methane reservoir. The paper discussed the materials and methods used for the study, including the sample site, sample collection and microbiological analysis. Results were presented in terms of DNA extractions; microbial diversity; and biofilm analyses. It was concluded that the findings from the study complemented previously reported studies which indicated the presence of diverse microbial communities in sediments containing methane hydrates. 9 refs., 5 figs.

  12. Establishment and Implementation of the Balingasay Marine Protected Area: A Community-Based Approach

    Directory of Open Access Journals (Sweden)

    Severino Salmo III

    2000-12-01

    Full Text Available A community-based approach in the establishment and implementation of a marine protected area (MPA in Balingasay, Bolinao, Pangasinan is presented. The factors necessary to facilitate the successful establishment and implementation of a community-managed MPA include heightening of environmental awareness, community mobilization, and legal/institutional and financial assistance. A heightened environmental awareness encouraged the community to undertake resource management action. The formation of a people’s organization, SAMMABAL (Samahan ng mga Mangingisda at Mamamayan ng Balingasay, was crucial in assessing environmental problems (e.g., overfishing and identifying the establishment of an MPA as a management tool to address the problem. SAMMABAL was also instrumental in eliciting community support for the issuance of a municipal ordinance in the establishment of the MPA. Subsequently, the organization initiated the patrolling of the MPA. Institutions involved in the community-based management of the MPA also included the multi-sectoral council (BRMC – Balingasay Resource Management Council and representatives from the barangay council and the municipal government. This institutional arrangement has proven to be very resilient, indicating a high probability of sustaining its successes despite some obstacles and shortcomings. Clear delineation of the role and functions of the institutions and the stakeholders was essential in advancing the initiative. This case study will draw on the lessons from the experience of a four-year community-managed MPA.

  13. [Hyperbolic growth of marine and continental biodiversity through the phanerozoic and community evolution].

    Science.gov (United States)

    Markov, A V; Korotaev, A V

    2008-01-01

    Among diverse models that are used to describe and interpret the changes in global biodiversity through the Phanerozoic, the exponential and logistic models (traditionally used in population biology) are the most popular. As we have recently demonstrated (Markov, Korotayev, 2007), the growth of the Phanerozoic marine biodiversity at genus level correlates better with the hyperbolic model (widely used in demography and macrosociology). Here we show that the hyperbolic model is also applicable to the Phanerozoic continental biota at genus and family levels, and to the marine biota at species, genus, and family levels. There are many common features in the evolutionary dynamics of the marine and continental biotas that imply similarity and common nature of the factors and mechanisms underlying the hyperbolic growth. Both marine and continental biotas are characterized by continuous growth of the mean longevity of taxa, by decreasing extinction and origination rates, by similar pattern of replacement of dominant groups, by stepwise accumulation of evolutionary stable, adaptable and "physiologically buffered" taxa with effective mechanisms of parental care, protection of early developmental stages, etc. At the beginning of the development of continental biota, the observed taxonomic diversity was substantially lower than that predicted by the hyperbolic model. We suggest that this is due, firstly, to the fact that, during the earliest stages of the continental biota evolution, the groups that are not preserved in the fossil record (such as soil bacteria, unicellular algae, lichens, etc.) played a fundamental role, and secondly, to the fact that the continental biota initially formed as a marginal portion of the marine biota, rather than a separate system. The hyperbolic dynamics is most prominent when both marine and continental biotas are considered together. This fact can be interpreted as a proof of the integrated nature of the biosphere. In the macrosociological

  14. Using community-level metrics to monitor the effects of marine protected areas on biodiversity.

    Science.gov (United States)

    Soykan, Candan U; Lewison, Rebecca L

    2015-06-01

    Marine protected areas (MPAs) are used to protect species, communities, and their associated habitats, among other goals. Measuring MPA efficacy can be challenging, however, particularly when considering responses at the community level. We gathered 36 abundance and 14 biomass data sets on fish assemblages and used meta-analysis to evaluate the ability of 22 distinct community diversity metrics to detect differences in community structure between MPAs and nearby control sites. We also considered the effects of 6 covariates-MPA size and age, MPA size and age interaction, latitude, total species richness, and level of protection-on each metric. Some common metrics, such as species richness and Shannon diversity, did not differ consistently between MPA and control sites, whereas other metrics, such as total abundance and biomass, were consistently different across studies. Metric responses derived from the biomass data sets were more consistent than those based on the abundance data sets, suggesting that community-level biomass differs more predictably than abundance between MPA and control sites. Covariate analyses indicated that level of protection, latitude, MPA size, and the interaction between MPA size and age affect metric performance. These results highlight a handful of metrics, several of which are little known, that could be used to meet the increasing demand for community-level indicators of MPA effectiveness. © 2015 Society for Conservation Biology.

  15. Effects of organic pollution on biological communities of marine biofilm on hard substrata.

    Science.gov (United States)

    Sanz-Lázaro, C; Fodelianakis, S; Guerrero-Meseguer, L; Marín, A; Karakassis, I

    2015-06-01

    We examined the effect of organic enrichment on diatom and bacterial assemblages of marine epilithic biofilms on two locations in the Mediterranean, one situated in Spain and the other in Greece. Total organic carbon, total organic nitrogen, stable isotopes (δ(13)C and δ(15)N) and chlorophyll a indicated significant incorporation of organic wastes, increased primary production and trophic niche modifications on the biofilms close to the organic enrichment source. In Spain, where the organic load was higher than in Greece, diatom and, to some extent, bacterial assemblages varied following the organic enrichment gradient. The taxonomic richness of diatom and bacterial communities was not influenced by organic enrichment. Classical community parameters showed consistent patterns to organic pollution in both locations, whereas community assemblages were only influenced when organic pollution was greatest. The successional patterns of these communities were similar to other epilithic communities. The modification of community assemblages induced by organic pollution may affect ecological functions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Biodiesel production from microalgal isolates of southern Pakistan and quantification of FAMEs by GC-MS/MS analysis

    Directory of Open Access Journals (Sweden)

    Musharraf Syed

    2012-12-01

    Full Text Available Abstract Background Microalgae have attracted major interest as a sustainable source for biodiesel production on commercial scale. This paper describes the screening of six microalgal species, Scenedesmus quadricauda, Scenedesmus acuminatus, Nannochloropsis sp., Anabaena sp., Chlorella sp. and Oscillatoria sp., isolated from fresh and marine water resources of southern Pakistan for biodiesel production and the GC-MS/MS analysis of their fatty acid methyl esters (FAMEs. Results Growth rate, biomass productivity and oil content of each algal species have been investigated under autotrophic condition. Biodiesel was produced from algal oil by acid catalyzed transesterification reaction and resulting fatty acid methyl esters (FAMEs content was analyzed by GC/MS. Fatty acid profiling of the biodiesel, obtained from various microalgal oils showed high content of C-16:0, C-18:0, cis-Δ9C-18:1, cis-Δ11C-18:1 (except Scenedesmus quadricauda and 10-hydroxyoctadecanoic (except Scenedesmus acuminatus. Absolute amount of C-14:0, C-16:0 and C-18:0 by a validated GC-MS/MS method were found to be 1.5-1.7, 15.0-42.5 and 4.2-18.4 mg/g, respectively, in biodiesel obtained from various microalgal oils. Biodiesel was also characterized in terms of cetane number, kinematic viscosity, density and higher heating value and compared with the standard values. Conclusion Six microalgae of local origin were screened for biodiesel production. A method for absolute quantification of three important saturated fatty acid methyl esters (C-14, C-16 and C-18 by gas chromatography-tandem mass spectrometry (GC-MS/MS, using multiple reactions monitoring (MRM mode, was employed for the identification and quantification of biodiesels obtained from various microalgal oils. The results suggested that locally found microalgae can be sustainably harvested for the production of biodiesel. This offers the tremendous economic opportunity for an energy-deficient nation.

  17. Community size and metabolic rates of psychrophilic sulfate-reducing bacteria in Arctic marine sediments

    DEFF Research Database (Denmark)

    Knoblauch, C.; Jørgensen, BB; Harder, J.

    1999-01-01

    The numbers of sulfate reducers in two Arctic sediments within situ temperatures of 2.6 and -1.7 degrees C were determined. Most-probable-number counts were higher at 10 degrees C than at 20 degrees C, indicating the predominance of a psychrophilic community. Mean specific sulfate reduction rates...... of 19 isolated psychrophiles were compared to corresponding rates of 9 marine, mesophilic sulfate-reducing bacteria. The results indicate that, as a physiological adaptation to the permanently cold Arctic environment, psychrophilic sulfate reducers have considerably higher specific metabolic rates than...... their mesophilic counterparts at similarly low temperatures....

  18. Ocean Filmmaking Camp @ Duke Marine Lab: Building Community with Ocean Science for a Better World

    Science.gov (United States)

    De Oca, M.; Noll, S.

    2016-02-01

    A democratic society requires that its citizens are informed of everyday's global issues. Out of all issues those related to ocean conservation can be hard to grasp for the general public and especially so for disadvantaged racial and ethnic groups. Opportunity-scarce communities generally have more limited access to the ocean and to science literacy programs. The Ocean Filmmaking Camp @ Duke Marine Lab (OFC@DUML) is an effort to address this gap at the level of high school students in a small coastal town. We designed a six-week summer program to nurture the talents of high school students from under-represented communities in North Carolina with training in filmmaking, marine science and conservation. Our science curriculum is especially designed to present the science in a locally and globally-relevant context. Class discussions, field trips and site visits develop the students' cognitive abilities while they learn the value of the natural environment they live in. Through filmmaking students develop their voice and their media literacy, while connecting with their local community, crossing class and racial barriers. By the end of the summer this program succeeds in encouraging students to engage in the democratic process on ocean conservation, climate change and other everyday affairs affecting their local communities. This presentation will cover the guiding principles followed in the design of the program, and how this high impact-low cost program is implemented. In its first year the program was co-directed by a graduate student and a local high school teacher, who managed more than 20 volunteers with a total budget of $1,500. The program's success was featured in the local newspaper and Duke University's Environment Magazine. This program is an example of how ocean science can play a part in building a better world, knitting diverse communities into the fabric of the larger society with engaged and science-literate citizens living rewarding lives.

  19. Temporal Stability of the Microbial Community in Sewage-Polluted Seawater Exposed to Natural Sunlight Cycles and Marine Microbiota

    Science.gov (United States)

    Sassoubre, Lauren M.; Yamahara, Kevan M.

    2015-01-01

    Billions of gallons of untreated wastewater enter the coastal ocean each year. Once sewage microorganisms are in the marine environment, they are exposed to environmental stressors, such as sunlight and predation. Previous research has investigated the fate of individual sewage microorganisms in seawater but not the entire sewage microbial community. The present study used next-generation sequencing (NGS) to examine how the microbial community in sewage-impacted seawater changes over 48 h when exposed to natural sunlight cycles and marine microbiota. We compared the results from microcosms composed of unfiltered seawater (containing naturally occurring marine microbiota) and filtered seawater (containing no marine microbiota) to investigate the effect of marine microbiota. We also compared the results from microcosms that were exposed to natural sunlight cycles with those from microcosms kept in the dark to investigate the effect of sunlight. The microbial community composition and the relative abundance of operational taxonomic units (OTUs) changed over 48 h in all microcosms. Exposure to sunlight had a significant effect on both community composition and OTU abundance. The effect of marine microbiota, however, was minimal. The proportion of sewage-derived microorganisms present in the microcosms decreased rapidly within 48 h, and the decrease was the most pronounced in the presence of both sunlight and marine microbiota, where the proportion decreased from 85% to 3% of the total microbial community. The results from this study demonstrate the strong effect that sunlight has on microbial community composition, as measured by NGS, and the importance of considering temporal effects in future applications of NGS to identify microbial pollution sources. PMID:25576619

  20. Protection enhances community and habitat stability: evidence from a mediterranean marine protected area.

    Science.gov (United States)

    Fraschetti, Simonetta; Guarnieri, Giuseppe; Bevilacqua, Stanislao; Terlizzi, Antonio; Boero, Ferdinando

    2013-01-01

    Rare evidences support that Marine Protected Areas (MPAs) enhance the stability of marine habitats and assemblages. Based on nine years of observation (2001-2009) inside and outside a well managed MPA, we assessed the potential of conservation and management actions to modify patterns of spatial and/or temporal variability of Posidonia oceanica meadows, the lower midlittoral and the shallow infralittoral rock assemblages. Significant differences in both temporal variations and spatial patterns were observed between protected and unprotected locations. A lower temporal variability in the protected vs. unprotected assemblages was found in the shallow infralittoral, demonstrating that, at least at local scale, protection can enhance community stability. Macrobenthos with long-lived and relatively slow-growing invertebrates and structurally complex algal forms were homogeneously distributed in space and went through little fluctuations in time. In contrast, a mosaic of disturbed patches featured unprotected locations, with small-scale shifts from macroalgal stands to barrens, and harsh temporal variations between the two states. Opposite patterns of spatial and temporal variability were found for the midlittoral assemblages. Despite an overall clear pattern of seagrass regression through time, protected meadows showed a significantly higher shoot density than unprotected ones, suggesting a higher resistance to local human activities. Our results support the assumption that the exclusion/management of human activities within MPAs enhance the stability of the structural components of protected marine systems, reverting or arresting threat-induced trajectories of change.

  1. The tropicalization of temperate marine ecosystems: climate-mediated changes in herbivory and community phase shifts

    Science.gov (United States)

    Vergés, Adriana; Steinberg, Peter D.; Hay, Mark E.; Poore, Alistair G. B.; Campbell, Alexandra H.; Ballesteros, Enric; Heck, Kenneth L.; Booth, David J.; Coleman, Melinda A.; Feary, David A.; Figueira, Will; Langlois, Tim; Marzinelli, Ezequiel M.; Mizerek, Toni; Mumby, Peter J.; Nakamura, Yohei; Roughan, Moninya; van Sebille, Erik; Gupta, Alex Sen; Smale, Dan A.; Tomas, Fiona; Wernberg, Thomas; Wilson, Shaun K.

    2014-01-01

    Climate-driven changes in biotic interactions can profoundly alter ecological communities, particularly when they impact foundation species. In marine systems, changes in herbivory and the consequent loss of dominant habitat forming species can result in dramatic community phase shifts, such as from coral to macroalgal dominance when tropical fish herbivory decreases, and from algal forests to ‘barrens’ when temperate urchin grazing increases. Here, we propose a novel phase-shift away from macroalgal dominance caused by tropical herbivores extending their range into temperate regions. We argue that this phase shift is facilitated by poleward-flowing boundary currents that are creating ocean warming hotspots around the globe, enabling the range expansion of tropical species and increasing their grazing rates in temperate areas. Overgrazing of temperate macroalgae by tropical herbivorous fishes has already occurred in Japan and the Mediterranean. Emerging evidence suggests similar phenomena are occurring in other temperate regions, with increasing occurrence of tropical fishes on temperate reefs. PMID:25009065

  2. Metagenomic Sequencing of Marine Periphyton: Taxonomic and Functional Insights into Biofilm Communities

    Directory of Open Access Journals (Sweden)

    Kemal eSanli

    2015-10-01

    Full Text Available Periphyton communities are complex phototrophic, multispecies biofilms that develop on surfaces in aquatic environments. These communities harbor a large diversity of organisms comprising viruses, bacteria, algae, fungi, protozoans and metazoans. However, thus far the total biodiversity of periphyton has not been described. In this study, we use metagenomics to characterize periphyton communities from the marine environment of the Swedish west coast. Although we found approximately ten times more eukaryotic rRNA marker gene sequences compared to prokaryotic, the whole metagenome-based similarity searches showed that bacteria constitute the most abundant phyla in these biofilms. We show that marine periphyton encompass a range of heterotrophic and phototrophic organisms. Heterotrophic bacteria, including the majority of proteobacterial clades and Bacteroidetes, and eukaryotic macro-invertebrates were found to dominate periphyton. The phototrophic groups comprise Cyanobacteria and the alpha-proteobacterial genus Roseobacter, followed by different micro- and macro-algae. We also assess the metabolic pathways that predispose these communities to an attached lifestyle. Functional indicators of the biofilm form of life in periphyton involve genes coding for enzymes that catalyze the production and degradation of extracellular polymeric substances, mainly in the form of complex sugars such as starch and glycogen-like meshes together with chitin. Genes for 278 different transporter proteins were detected in the metagenome, constituting the most abundant protein complexes. Finally, genes encoding enzymes that participate in anaerobic pathways, such as denitrification and methanogenesis, were detected suggesting the presence of anaerobic or low-oxygen micro-zones within the biofilms.

  3. Detection of large numbers of novel sequences in the metatranscriptomes of complex marine microbial communities.

    Science.gov (United States)

    Gilbert, Jack A; Field, Dawn; Huang, Ying; Edwards, Rob; Li, Weizhong; Gilna, Paul; Joint, Ian

    2008-08-22

    Sequencing the expressed genetic information of an ecosystem (metatranscriptome) can provide information about the response of organisms to varying environmental conditions. Until recently, metatranscriptomics has been limited to microarray technology and random cloning methodologies. The application of high-throughput sequencing technology is now enabling access to both known and previously unknown transcripts in natural communities. We present a study of a complex marine metatranscriptome obtained from random whole-community mRNA using the GS-FLX Pyrosequencing technology. Eight samples, four DNA and four mRNA, were processed from two time points in a controlled coastal ocean mesocosm study (Bergen, Norway) involving an induced phytoplankton bloom producing a total of 323,161,989 base pairs. Our study confirms the finding of the first published metatranscriptomic studies of marine and soil environments that metatranscriptomics targets highly expressed sequences which are frequently novel. Our alternative methodology increases the range of experimental options available for conducting such studies and is characterized by an exceptional enrichment of mRNA (99.92%) versus ribosomal RNA. Analysis of corresponding metagenomes confirms much higher levels of assembly in the metatranscriptomic samples and a far higher yield of large gene families with >100 members, approximately 91% of which were novel. This study provides further evidence that metatranscriptomic studies of natural microbial communities are not only feasible, but when paired with metagenomic data sets, offer an unprecedented opportunity to explore both structure and function of microbial communities--if we can overcome the challenges of elucidating the functions of so many never-seen-before gene families.

  4. Effects of marine reserves versus nursery habitat availability on structure of reef fish communities.

    Science.gov (United States)

    Nagelkerken, Ivan; Grol, Monique G G; Mumby, Peter J

    2012-01-01

    No-take marine fishery reserves sustain commercial stocks by acting as buffers against overexploitation and enhancing fishery catches in adjacent areas through spillover. Likewise, nursery habitats such as mangroves enhance populations of some species in adjacent habitats. However, there is lack of understanding of the magnitude of stock enhancement and the effects on community structure when both protection from fishing and access to nurseries concurrently act as drivers of fish population dynamics. In this study we test the separate as well as interactive effects of marine reserves and nursery habitat proximity on structure and abundance of coral reef fish communities. Reserves had no effect on fish community composition, while proximity to nursery habitat only had a significant effect on community structure of species that use mangroves or seagrass beds as nurseries. In terms of reef fish biomass, proximity to nursery habitat by far outweighed (biomass 249% higher than that in areas with no nursery access) the effects of protection from fishing in reserves (biomass 21% lower than non-reserve areas) for small nursery fish (≤ 25 cm total length). For large-bodied individuals of nursery species (>25 cm total length), an additive effect was present for these two factors, although fish benefited more from fishing protection (203% higher biomass) than from proximity to nurseries (139% higher). The magnitude of elevated biomass for small fish on coral reefs due to proximity to nurseries was such that nursery habitats seem able to overrule the usually positive effects on fish biomass by reef reserves. As a result, conservation of nursery habitats gains importance and more consideration should be given to the ecological processes that occur along nursery-reef boundaries that connect neighboring ecosystems.

  5. Effects of marine reserves versus nursery habitat availability on structure of reef fish communities.

    Directory of Open Access Journals (Sweden)

    Ivan Nagelkerken

    Full Text Available No-take marine fishery reserves sustain commercial stocks by acting as buffers against overexploitation and enhancing fishery catches in adjacent areas through spillover. Likewise, nursery habitats such as mangroves enhance populations of some species in adjacent habitats. However, there is lack of understanding of the magnitude of stock enhancement and the effects on community structure when both protection from fishing and access to nurseries concurrently act as drivers of fish population dynamics. In this study we test the separate as well as interactive effects of marine reserves and nursery habitat proximity on structure and abundance of coral reef fish communities. Reserves had no effect on fish community composition, while proximity to nursery habitat only had a significant effect on community structure of species that use mangroves or seagrass beds as nurseries. In terms of reef fish biomass, proximity to nursery habitat by far outweighed (biomass 249% higher than that in areas with no nursery access the effects of protection from fishing in reserves (biomass 21% lower than non-reserve areas for small nursery fish (≤ 25 cm total length. For large-bodied individuals of nursery species (>25 cm total length, an additive effect was present for these two factors, although fish benefited more from fishing protection (203% higher biomass than from proximity to nurseries (139% higher. The magnitude of elevated biomass for small fish on coral reefs due to proximity to nurseries was such that nursery habitats seem able to overrule the usually positive effects on fish biomass by reef reserves. As a result, conservation of nursery habitats gains importance and more consideration should be given to the ecological processes that occur along nursery-reef boundaries that connect neighboring ecosystems.

  6. Islands in a Sea of Mud: Insights From Terrestrial Island Theory for Community Assembly on Insular Marine Substrata.

    Science.gov (United States)

    Meyer, K S

    Most marine hard-bottom habitats are isolated, separated from other similar habitats by sand or mud flats, and can be considered analogous to terrestrial islands. The extensive scientific literature on terrestrial islands provides a theoretical framework for the analysis of isolated marine habitats. More individuals and higher species richness occur on larger marine substrata, a pattern that resembles terrestrial islands. However, while larger terrestrial islands have greater habitat diversity and productivity, the higher species richness on larger marine hard substrata can be explained by simple surface area and hydrodynamic phenomena: larger substrata extend further into the benthic boundary, exposing fauna to faster current and higher food supply. Marine island-like communities are also influenced by their distance to similar habitats, but investigations into the reproductive biology and dispersal ability of individual species are required for a more complete understanding of population connectivity. On terrestrial islands, nonrandom co-occurrence patterns have been attributed to interspecific competition, but while nonrandom co-occurrence patterns have been found for marine fauna, different mechanisms are responsible, including epibiontism. Major knowledge gaps for community assembly in isolated marine habitats include the degree of connectivity between isolated habitats, mechanisms of succession, and the extent of competition on hard substrata, particularly in the deep sea. Anthropogenic hard substrata of known age can be used opportunistically as "natural" laboratories to begin answering these questions. © 2017 Elsevier Ltd. All rights reserved.

  7. Biogeochemical interactions control a temporal succession in the elemental composition of marine communities

    KAUST Repository

    Martiny, Adam C.; Talarmin, Agathe Anne Gaelle; Mouginot, Cé line; Lee, Jeanette A.; Huang, Jeremy S.; Gellene, Alyssa G.; Caron, David A.

    2015-01-01

    Recent studies have revealed clear regional differences in the particulate organic matter composition and stoichiometry of plankton communities. In contrast, less is known about potential mechanisms and patterns of temporal changes in the elemental composition of marine systems. Here, we monitored weekly changes in environmental conditions, phytoplankton abundances, and particulate organic carbon, nitrogen, and phosphorus concentrations over a 3-yr period. We found that variation in the particulate organic matter (POM) concentrations and ratios were related to seasonal oscillations of environmental conditions and phytoplankton abundances. Periods with low temperature, high nutrient concentrations and a dominance of large phytoplankton corresponded to low C : N : P and vice-versa for warmer periods during the summer and fall. In addition to seasonal changes, we observed a multiyear increase in POM C : P and N : P that might be associated with the Pacific Decadal Oscillation. Finally, there was substantial short-term variability in all factors but similar linkages between environmental variability and elemental composition as observed on seasonal and interannual time-scales. Using a feed-forward neural network, we could explain a large part of the variation in POM concentrations and ratios based on changes in environmental conditions and phytoplankton abundances. The apparent links across all time-scales between changes in physics, chemistry, phytoplankton, and POM concentrations and ratios suggest we have identified key controls of the elemental composition of marine communities in this region.

  8. Biogeochemical interactions control a temporal succession in the elemental composition of marine communities

    KAUST Repository

    Martiny, Adam C.

    2015-11-23

    Recent studies have revealed clear regional differences in the particulate organic matter composition and stoichiometry of plankton communities. In contrast, less is known about potential mechanisms and patterns of temporal changes in the elemental composition of marine systems. Here, we monitored weekly changes in environmental conditions, phytoplankton abundances, and particulate organic carbon, nitrogen, and phosphorus concentrations over a 3-yr period. We found that variation in the particulate organic matter (POM) concentrations and ratios were related to seasonal oscillations of environmental conditions and phytoplankton abundances. Periods with low temperature, high nutrient concentrations and a dominance of large phytoplankton corresponded to low C : N : P and vice-versa for warmer periods during the summer and fall. In addition to seasonal changes, we observed a multiyear increase in POM C : P and N : P that might be associated with the Pacific Decadal Oscillation. Finally, there was substantial short-term variability in all factors but similar linkages between environmental variability and elemental composition as observed on seasonal and interannual time-scales. Using a feed-forward neural network, we could explain a large part of the variation in POM concentrations and ratios based on changes in environmental conditions and phytoplankton abundances. The apparent links across all time-scales between changes in physics, chemistry, phytoplankton, and POM concentrations and ratios suggest we have identified key controls of the elemental composition of marine communities in this region.

  9. Natural acidification changes the timing and rate of succession, alters community structure, and increases homogeneity in marine biofouling communities.

    Science.gov (United States)

    Brown, Norah E M; Milazzo, Marco; Rastrick, Samuel P S; Hall-Spencer, Jason M; Therriault, Thomas W; Harley, Christopher D G

    2018-01-01

    Ocean acidification may have far-reaching consequences for marine community and ecosystem dynamics, but its full impacts remain poorly understood due to the difficulty of manipulating pCO 2 at the ecosystem level to mimic realistic fluctuations that occur on a number of different timescales. It is especially unclear how quickly communities at various stages of development respond to intermediate-scale pCO 2 change and, if high pCO 2 is relieved mid-succession, whether past acidification effects persist, are reversed by alleviation of pCO 2 stress, or are worsened by departures from prior high pCO 2 conditions to which organisms had acclimatized. Here, we used reciprocal transplant experiments along a shallow water volcanic pCO 2 gradient to assess the importance of the timing and duration of high pCO 2 exposure (i.e., discrete events at different stages of successional development vs. continuous exposure) on patterns of colonization and succession in a benthic fouling community. We show that succession at the acidified site was initially delayed (less community change by 8 weeks) but then caught up over the next 4 weeks. These changes in succession led to homogenization of communities maintained in or transplanted to acidified conditions, and altered community structure in ways that reflected both short- and longer-term acidification history. These community shifts are likely a result of interspecific variability in response to increased pCO 2 and changes in species interactions. High pCO 2 altered biofilm development, allowing serpulids to do best at the acidified site by the end of the experiment, although early (pretransplant) negative effects of pCO 2 on recruitment of these worms were still detectable. The ascidians Diplosoma sp. and Botryllus sp. settled later and were more tolerant to acidification. Overall, transient and persistent acidification-driven changes in the biofouling community, via both past and more recent exposure, could have important

  10. Qualitative Analysis of Microbial Dynamics during Anaerobic Digestion of Microalgal Biomass in a UASB Reactor

    Directory of Open Access Journals (Sweden)

    Anna Doloman

    2017-01-01

    Full Text Available Anaerobic digestion (AD is a microbiologically coordinated process with dynamic relationships between bacterial players. Current understanding of dynamic changes in the bacterial composition during the AD process is incomplete. The objective of this research was to assess changes in bacterial community composition that coordinates with anaerobic codigestion of microalgal biomass cultivated on municipal wastewater. An upflow anaerobic sludge blanket reactor was used to achieve high rates of microalgae decomposition and biogas production. Samples of the sludge were collected throughout AD and extracted DNA was subjected to next-generation sequencing using methanogen mcrA gene specific and universal bacterial primers. Analysis of the data revealed that samples taken at different stages of AD had varying bacterial composition. A group consisting of Bacteroidales, Pseudomonadales, and Enterobacteriales was identified to be putatively responsible for the hydrolysis of microalgal biomass. The methanogenesis phase was dominated by Methanosarcina mazei. Results of observed changes in the composition of microbial communities during AD can be used as a road map to stimulate key bacterial species identified at each phase of AD to increase yield of biogas and rate of substrate decomposition. This research demonstrates a successful exploitation of methane production from microalgae without any biomass pretreatment.

  11. Qualitative Analysis of Microbial Dynamics during Anaerobic Digestion of Microalgal Biomass in a UASB Reactor

    Science.gov (United States)

    Doloman, Anna; Soboh, Yousef; Walters, Andrew J.; Sims, Ronald C.

    2017-01-01

    Anaerobic digestion (AD) is a microbiologically coordinated process with dynamic relationships between bacterial players. Current understanding of dynamic changes in the bacterial composition during the AD process is incomplete. The objective of this research was to assess changes in bacterial community composition that coordinates with anaerobic codigestion of microalgal biomass cultivated on municipal wastewater. An upflow anaerobic sludge blanket reactor was used to achieve high rates of microalgae decomposition and biogas production. Samples of the sludge were collected throughout AD and extracted DNA was subjected to next-generation sequencing using methanogen mcrA gene specific and universal bacterial primers. Analysis of the data revealed that samples taken at different stages of AD had varying bacterial composition. A group consisting of Bacteroidales, Pseudomonadales, and Enterobacteriales was identified to be putatively responsible for the hydrolysis of microalgal biomass. The methanogenesis phase was dominated by Methanosarcina mazei. Results of observed changes in the composition of microbial communities during AD can be used as a road map to stimulate key bacterial species identified at each phase of AD to increase yield of biogas and rate of substrate decomposition. This research demonstrates a successful exploitation of methane production from microalgae without any biomass pretreatment. PMID:29259629

  12. Microalgal production--a close look at the economics.

    Science.gov (United States)

    Norsker, Niels-Henrik; Barbosa, Maria J; Vermuë, Marian H; Wijffels, René H

    2011-01-01

    Worldwide, microalgal biofuel production is being investigated. It is strongly debated which type of production technology is the most adequate. Microalgal biomass production costs were calculated for 3 different micro algal production systems operating at commercial scale today: open ponds, horizontal tubular photobioreactors and flat panel photobioreactors. For the 3 systems, resulting biomass production costs including dewatering, were 4.95, 4.15 and 5.96 € per kg, respectively. The important cost factors are irradiation conditions, mixing, photosynthetic efficiency of systems, medium- and carbon dioxide costs. Optimizing production with respect to these factors, a price of € 0.68 per kg resulted. At this cost level microalgae become a promising feedstock for biodiesel and bulk chemicals. Photobioreactors may become attractive for microalgal biofuel production. Copyright © 2010 Elsevier Inc. All rights reserved.

  13. Ecology and biotechnological potential of bacterial community from three marine sponges of the coast of Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    FÁBIO V. DE ARAÚJO

    2017-12-01

    Full Text Available ABSTRACT Marine sponges has been a large reservoir of microbial diversity, with the presence of many species specific populations as well as producing biologically active compounds, which has attracted great biotechnological interest. In order to verify the influence of the environment in the composition of the bacterial community present in marine sponges and biotechnological potential of bacteria isolated from these organisms, three species of sponges and the waters surrounding them were collected in different beaches of Rio de Janeiro, Brazil. The profile of the bacterial community present in sponges and water was obtained by PCR-DGGE technique and the biotechnological potential of the strains isolated by producing amylase, cellulase, protease and biosurfactants. The results showed that despite the influence of the environment in the composition of the microbial community, studied marine sponges shown to have specific bacterial populations, with some, showing potential in the production of substances of biotechnological applications.

  14. Perspectives of microalgal biofuels as a renewable source of energy

    International Nuclear Information System (INIS)

    Kiran, Bala; Kumar, Ritunesh; Deshmukh, Devendra

    2014-01-01

    Highlights: • Microalgae offer solution of wastewater treatment, CO 2 sequestration, and energy crises. • Microalgal biofuel is renewable, nontoxic and environmentally friendly option. • Integration of wastewater treatment with biofuels production has made them more cost effective. • This article details out the potential production process and benefits of microalgal biofuels. - Abstract: Excessive use of fossil fuels to satisfy our rapidly increasing energy demand has created severe environmental problems, such as air pollution, acid rain and global warming. Biofuels are a potential alternative to fossil fuels. First- and second-generation biofuels face criticism due to food security and biodiversity issues. Third-generation biofuels, based on microalgae, seem to be a plausible solution to the current energy crisis, as their oil-producing capability is many times higher than that of various oil crops. Microalgae are the fastest-growing plants and can serve as a sustainable energy source for the production of biodiesel and several other biofuels by conversion of sunlight into chemical energy. Biofuels produced from microalgae are renewable, non-toxic, biodegradable and environment friendly. Microalgae can be grown in open pond systems or closed photobioreactors. Microalgal biofuels are a potential means to keep the development of human activities in synchronization with the environment. The integration of wastewater treatment with biofuel production using microalgae has made microalgal biofuels more attractive and cost effective. A biorefinery approach can also be used to improve the economics of biofuel production, in which all components of microalgal biomass (i.e., proteins, lipids and carbohydrates) are used to produce useful products. The integration of various processes for maximum economic and environmental benefits minimizes the amount of waste produced and the pollution level. This paper presents an overview of various aspects associated with

  15. Dependence of carbon dioxide concentration on microalgal carbon dioxide fixation

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Yeoung Sang; Park, Song Moon [Department of Chemical Engineering, School of Environmental Engineering, Pohang University of Science and Technology, Pohang (Korea); Bolesky, Bohumil [Department of Chemical Engineering, McGill University (Canada)

    1999-10-01

    Batch cultivation of chlorella vulgaris was carried out under various CO{sub 2} concentrations in order to understand and describe mathematically the CO{sub 2} inhibition of microalgal CO{sub 2} fixation. The volumetric CO{sub 2} transfer coefficient from mixture gas to culture medium was estimated from the volumetric O{sub 2} transfer coefficient obtained experimentally. Using this transfer coefficient and aquatic equilibrium relationship between dissolved inorganic carbons, the behavior of dissolved CO{sub 2} was calculated during microalgal culture. When air containing 0.035%(v/v) CO{sub 2} was supplied into microalgal culture, the fixation rate was limited by CO{sub 2} transfer rate. However, the limitation was disappeared by supplying mixture gas containing above 2%(v/v) CO{sub 2} and the dissolved CO{sub 2} concentration was maintained at the saturated value. In the range of CO{sub 2} partial pressure in the flue gases from thermal power sations and steel-making plants, the microalgal CO{sub 2} fixation rate was inhibited. The CO{sub 2} fixation rate was successfully formulated by a new empirical equation as a function of dissolved CO{sub 2} concentration, which could be useful for modeling and simulating the performance of photobioreaction with enriched CO{sub 2}. Also, it was found that the CO{sub 2} inhibition of microalgal CO{sub 2} fixation was reversible and that microalgal CO{sub 2} fixation process could be stable against a shock of unusually high CO{sub 2} concentration. 29 refs., 8 figs.

  16. Protist communities in a marine oxygen minimum zone off Costa Rica by 454 pyrosequencing

    Science.gov (United States)

    Jing, H.; Rocke, E.; Kong, L.; Xia, X.; Liu, H.; Landry, M. R.

    2015-08-01

    Marine planktonic protists, including microalgae and protistan grazers, are an important contributor to global primary production and carbon and mineral cycles, however, little is known about their population shifts along the oxic-anoxic gradient in the water column. We used 454 pyrosequencing of the 18S rRNA gene and gene transcripts to study the community composition of whole and active protists throughout a water column in the Costa Rica Dome, where a stable oxygen minimum zone (OMZ) exists at a depth of 400~700 m. A clear shift of protist composition from photosynthetic Dinoflagellates in the surface to potential parasitic Dinoflagellates and Ciliates in the deeper water was revealed along the vertical profile at both rRNA and rDNA levels. Those protist groups recovered only at the rDNA level represent either lysed aggregates sinking from the upper waters or potential hosts for parasitic groups. UPGMA clustering demonstrated that total and active protists in the anoxic core of OMZ (550 m) were distinct from those in other water depths. The reduced community diversity and presence of a parasitic/symbiotic trophic lifestyle in the OMZ, especially the anoxic core, suggests that OMZs can exert a selective pressure on protist communities. Such changes in community structure and a shift in trophic lifestyle could result in a modulation of the microbial loop and associated biogeochemical cycling.

  17. Follow-up trends of parasite community alteration in a marine fish after the Prestige oil-spill: shifting baselines?

    Science.gov (United States)

    Pérez-del-Olmo, A; Montero, F E; Raga, J A; Fernández, M; Kostadinova, A

    2009-01-01

    This study evaluates the follow-up trends in the composition and structure of the parasite communities in the marine sparid Boops boops after the Prestige oil-spill. A total of 400 fish comprising 11 seasonal samples was analyzed from three impacted localities on the Atlantic coast of Spain. A large number of parasite species was recovered only after the spill thus suggesting a substantial alteration of the marine food webs. Post-spill communities exhibited higher richness and abundance due to the significant changes in the abundance of the common species, the latter indicating accelerated parasite transmission rates. Multivariate analyses at two nested scales detected a directional trend in parasite community succession towards the pre-spill situation, however, with no full support for community recovery. The state of parasite communities in 2005-2006 may provide the new baseline data which can serve as a framework for quantifying the impact of potential future spills in the region.

  18. Superstructure optimization of biodiesel production from microalgal biomass

    DEFF Research Database (Denmark)

    Rizwan, Muhammad; Lee, Jay H.; Gani, Rafiqul

    2013-01-01

    In this study, we propose a mixed integer nonlinear programming (MINLP) model for superstructure based optimization of biodiesel production from microalgal biomass. The proposed superstructure includes a number of major processing steps for the production of biodiesel from microalgal biomass...... for the production of biodiesel from microalgae. The proposed methodology is tested by implementing on a specific case study. The MINLP model is implemented and solved in GAMS using a database built in Excel. The results from the optimization are analyzed and their significances are discussed....

  19. Effects of trophic skewing of species richness on ecosystem functioning in a diverse marine community.

    Directory of Open Access Journals (Sweden)

    Pamela L Reynolds

    Full Text Available Widespread overharvesting of top consumers of the world's ecosystems has "skewed" food webs, in terms of biomass and species richness, towards a generally greater domination at lower trophic levels. This skewing is exacerbated in locations where exotic species are predominantly low-trophic level consumers such as benthic macrophytes, detritivores, and filter feeders. However, in some systems where numerous exotic predators have been added, sometimes purposefully as in many freshwater systems, food webs are skewed in the opposite direction toward consumer dominance. Little is known about how such modifications to food web topology, e.g., changes in the ratio of predator to prey species richness, affect ecosystem functioning. We experimentally measured the effects of trophic skew on production in an estuarine food web by manipulating ratios of species richness across three trophic levels in experimental mesocosms. After 24 days, increasing macroalgal richness promoted both plant biomass and grazer abundance, although the positive effect on plant biomass disappeared in the presence of grazers. The strongest trophic cascade on the experimentally stocked macroalgae emerged in communities with a greater ratio of prey to predator richness (bottom-rich food webs, while stronger cascades on the accumulation of naturally colonizing algae (primarily microalgae with some early successional macroalgae that recruited and grew in the mesocosms generally emerged in communities with greater predator to prey richness (the more top-rich food webs. These results suggest that trophic skewing of species richness and overall changes in food web topology can influence marine community structure and food web dynamics in complex ways, emphasizing the need for multitrophic approaches to understand the consequences of marine extinctions and invasions.

  20. The lipid response of aerobic marine methanotroph communities under changing environmental conditions.

    Science.gov (United States)

    Rush, D.; Villanueva, L.; van der Meer, M.; S Sinninghe Damsté, J.

    2017-12-01

    Methane (CH4) originating from marine environments accounts for a significant amount of atmospheric greenhouse gas. Aerobic methanotrophs, which convert CH4 to CO­2, are responsible for quenching a part of this methane before its release. Modern-day climate projections show a rapid shift towards a warmer, more acidic ocean. How do these important methanotrophic communities respond to such changes to their environment? Here, we present the results of microcosm experiments from three marine regions influenced by CH4. Particulate organic matter and sediment were collected from the Black Sea, the Baltic Sea, and the North Sea, at depths ideal for aerobic methanotroph communities at the time of sampling (e.g. oxic, in area of active CH4 release). These were incubated under different temperatures, pHs, and labelled 13CH4 concentrations. We monitored methane concentration in these microcosms as an indication of 13CH4 consumption by methanotrophs. Once the methane concentration was lipids of the organisms oxidising methane in order to elucidate which organisms are performing methane oxidation and whether they synthesize specific biomarker lipids. Particular attention will be paid to the abundances and diversity of bacteriohopanepolyol lipids, known methanotroph biomarkers. The ultimate goal of our investigation is to determine the effect changes in these environmental parameters have on aerobic methanotroph community structures and their lipid fingerprints. By establishing reliable biomarker lipids for aerobic methanotrophy at certain conditions, we will then be able to investigate the contribution of aerobic methanotrophy throughout Earth's history, especially at times when CH4 concentrations were higher than they are at present.

  1. Climate-driven changes in functional biogeography of Arctic marine fish communities.

    Science.gov (United States)

    Frainer, André; Primicerio, Raul; Kortsch, Susanne; Aune, Magnus; Dolgov, Andrey V; Fossheim, Maria; Aschan, Michaela M

    2017-11-14

    Climate change triggers poleward shifts in species distribution leading to changes in biogeography. In the marine environment, fish respond quickly to warming, causing community-wide reorganizations, which result in profound changes in ecosystem functioning. Functional biogeography provides a framework to address how ecosystem functioning may be affected by climate change over large spatial scales. However, there are few studies on functional biogeography in the marine environment, and none in the Arctic, where climate-driven changes are most rapid and extensive. We investigated the impact of climate warming on the functional biogeography of the Barents Sea, which is characterized by a sharp zoogeographic divide separating boreal from Arctic species. Our unique dataset covered 52 fish species, 15 functional traits, and 3,660 stations sampled during the recent warming period. We found that the functional traits characterizing Arctic fish communities, mainly composed of small-sized bottom-dwelling benthivores, are being rapidly replaced by traits of incoming boreal species, particularly the larger, longer lived, and more piscivorous species. The changes in functional traits detected in the Arctic can be predicted based on the characteristics of species expected to undergo quick poleward shifts in response to warming. These are the large, generalist, motile species, such as cod and haddock. We show how functional biogeography can provide important insights into the relationship between species composition, diversity, ecosystem functioning, and environmental drivers. This represents invaluable knowledge in a period when communities and ecosystems experience rapid climate-driven changes across biogeographical regions. Copyright © 2017 the Author(s). Published by PNAS.

  2. Humpback whale populations share a core skin bacterial community: towards a health index for marine mammals?

    Directory of Open Access Journals (Sweden)

    Amy Apprill

    Full Text Available Microbes are now well regarded for their important role in mammalian health. The microbiology of skin--a unique interface between the host and environment--is a major research focus in human health and skin disorders, but is less explored in other mammals. Here, we report on a cross-population study of the skin-associated bacterial community of humpback whales (Megaptera novaeangliae, and examine the potential for a core bacterial community and its variability with host (endogenous or geographic/environmental (exogenous specific factors. Skin biopsies or freshly sloughed skin from 56 individuals were sampled from populations in the North Atlantic, North Pacific and South Pacific oceans and bacteria were characterized using 454 pyrosequencing of SSU rRNA genes. Phylogenetic and statistical analyses revealed the ubiquity and abundance of bacteria belonging to the Flavobacteria genus Tenacibaculum and the Gammaproteobacteria genus Psychrobacter across the whale populations. Scanning electron microscopy of skin indicated that microbial cells colonize the skin surface. Despite the ubiquity of Tenacibaculum and Psychrobater spp., the relative composition of the skin-bacterial community differed significantly by geographic area as well as metabolic state of the animals (feeding versus starving during migration and breeding, suggesting that both exogenous and endogenous factors may play a role in influencing the skin-bacteria. Further, characteristics of the skin bacterial community from these free-swimming individuals were assembled and compared to two entangled and three dead individuals, revealing a decrease in the central or core bacterial community members (Tenacibaculum and Psychrobater spp., as well as the emergence of potential pathogens in the latter cases. This is the first discovery of a cross-population, shared skin bacterial community. This research suggests that the skin bacteria may be connected to humpback health and immunity and could

  3. Microalgal Mass Culture Data from Greenhouse Tanks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data is collected during experiments growing marine microalgae, on a pilot scale, to improve culture methods and yield. Cultures are typically 450 liters in...

  4. Large-scale assessment of benthic communities across multiple marine protected areas using an autonomous underwater vehicle.

    Science.gov (United States)

    Ferrari, Renata; Marzinelli, Ezequiel M; Ayroza, Camila Rezende; Jordan, Alan; Figueira, Will F; Byrne, Maria; Malcolm, Hamish A; Williams, Stefan B; Steinberg, Peter D

    2018-01-01

    Marine protected areas (MPAs) are designed to reduce threats to biodiversity and ecosystem functioning from anthropogenic activities. Assessment of MPAs effectiveness requires synchronous sampling of protected and non-protected areas at multiple spatial and temporal scales. We used an autonomous underwater vehicle to map benthic communities in replicate 'no-take' and 'general-use' (fishing allowed) zones within three MPAs along 7o of latitude. We recorded 92 taxa and 38 morpho-groups across three large MPAs. We found that important habitat-forming biota (e.g. massive sponges) were more prevalent and abundant in no-take zones, while short ephemeral algae were more abundant in general-use zones, suggesting potential short-term effects of zoning (5-10 years). Yet, short-term effects of zoning were not detected at the community level (community structure or composition), while community structure varied significantly among MPAs. We conclude that by allowing rapid, simultaneous assessments at multiple spatial scales, autonomous underwater vehicles are useful to document changes in marine communities and identify adequate scales to manage them. This study advanced knowledge of marine benthic communities and their conservation in three ways. First, we quantified benthic biodiversity and abundance, generating the first baseline of these benthic communities against which the effectiveness of three large MPAs can be assessed. Second, we identified the taxonomic resolution necessary to assess both short and long-term effects of MPAs, concluding that coarse taxonomic resolution is sufficient given that analyses of community structure at different taxonomic levels were generally consistent. Yet, observed differences were taxa-specific and may have not been evident using our broader taxonomic classifications, a classification of mid to high taxonomic resolution may be necessary to determine zoning effects on key taxa. Third, we provide an example of statistical analyses and

  5. Habitat dynamics, marine reserve status, and the decline and recovery of coral reef fish communities

    Science.gov (United States)

    Williamson, David H; Ceccarelli, Daniela M; Evans, Richard D; Jones, Geoffrey P; Russ, Garry R

    2014-01-01

    Severe climatic disturbance events often have major impacts on coral reef communities, generating cycles of decline and recovery, and in some extreme cases, community-level phase shifts from coral-to algal-dominated states. Benthic habitat changes directly affect reef fish communities, with low coral cover usually associated with low fish diversity and abundance. No-take marine reserves (NTRs) are widely advocated for conserving biodiversity and enhancing the sustainability of exploited fish populations. Numerous studies have documented positive ecological and socio-economic benefits of NTRs; however, the ability of NTRs to ameliorate the effects of acute disturbances on coral reefs has seldom been investigated. Here, we test these factors by tracking the dynamics of benthic and fish communities, including the important fishery species, coral trout (Plectropomus spp.), over 8 years in both NTRs and fished areas in the Keppel Island group, Great Barrier Reef, Australia. Two major disturbances impacted the reefs during the monitoring period, a coral bleaching event in 2006 and a freshwater flood plume in 2011. Both disturbances generated significant declines in coral cover and habitat complexity, with subsequent declines in fish abundance and diversity, and pronounced shifts in fish assemblage structure. Coral trout density also declined in response to the loss of live coral, however, the approximately 2:1 density ratio between NTRs and fished zones was maintained over time. The only post-disturbance refuges for coral trout spawning stocks were within the NTRs that escaped the worst effects of the disturbances. Although NTRs had little discernible effect on the temporal dynamics of benthic or fish communities, it was evident that the post-disturbance refuges for coral trout spawning stocks within some NTRs may be critically important to regional-scale population persistence and recovery. PMID:24634720

  6. Community Change within a Caribbean Coral Reef Marine Protected Area following Two Decades of Local Management

    KAUST Repository

    Noble, Mae M.

    2013-01-14

    Structural change in both the habitat and reef-associated fish assemblages within spatially managed coral reefs can provide key insights into the benefits and limitations of Marine Protected Areas (MPAs). While MPA zoning effects on particular target species are well reported, we are yet to fully resolve the various affects of spatial management on the structure of coral reef communities over decadal time scales. Here, we document mixed affects of MPA zoning on fish density, biomass and species richness over the 21 years since establishment of the Saba Marine Park (SMP). Although we found significantly greater biomass and species richness of reef-associated fishes within shallow habitats (5 meters depth) closed to fishing, this did not hold for deeper (15 m) habitats, and there was a widespread decline (38% decrease) in live hard coral cover and a 68% loss of carnivorous reef fishes across all zones of the SMP from the 1990s to 2008. Given the importance of live coral for the maintenance and replenishment of reef fishes, and the likely role of chronic disturbance in driving coral decline across the region, we explore how local spatial management can help protect coral reef ecosystems within the context of large-scale environmental pressures and disturbances outside the purview of local MPA management. © 2013 Noble et al.

  7. Community change within a Caribbean coral reef Marine Protected Area following two decades of local management.

    Directory of Open Access Journals (Sweden)

    Mae M Noble

    Full Text Available Structural change in both the habitat and reef-associated fish assemblages within spatially managed coral reefs can provide key insights into the benefits and limitations of Marine Protected Areas (MPAs. While MPA zoning effects on particular target species are well reported, we are yet to fully resolve the various affects of spatial management on the structure of coral reef communities over decadal time scales. Here, we document mixed affects of MPA zoning on fish density, biomass and species richness over the 21 years since establishment of the Saba Marine Park (SMP. Although we found significantly greater biomass and species richness of reef-associated fishes within shallow habitats (5 meters depth closed to fishing, this did not hold for deeper (15 m habitats, and there was a widespread decline (38% decrease in live hard coral cover and a 68% loss of carnivorous reef fishes across all zones of the SMP from the 1990s to 2008. Given the importance of live coral for the maintenance and replenishment of reef fishes, and the likely role of chronic disturbance in driving coral decline across the region, we explore how local spatial management can help protect coral reef ecosystems within the context of large-scale environmental pressures and disturbances outside the purview of local MPA management.

  8. Modeling the transformation of atmospheric CO2 into microalgal biomass.

    Science.gov (United States)

    Hasan, Mohammed Fahad; Vogt, Frank

    2017-10-23

    Marine phytoplankton acts as a considerable sink of atmospheric CO 2 as it sequesters large quantities of this greenhouse gas for biomass production. To assess microalgae's counterbalancing of global warming, the quantities of CO 2 they fix need to be determined. For this task, it is mandatory to understand which environmental and physiological parameters govern this transformation from atmospheric CO 2 to microalgal biomass. However, experimental analyses are challenging as it has been found that the chemical environment has a major impact on the physiological properties of the microalgae cells (diameter typ. 5-20 μm). Moreover, the cells can only chemically interact with their immediate vicinity and thus compound sequestration needs to be studied on a microscopic spatial scale. Due to these reasons, computer simulations are a more promising approach than the experimental studies. Modeling software has been developed that describes the dissolution of atmospheric CO 2 into oceans followed by the formation of HCO 3 - which is then transported to individual microalgae cells. The second portion of this model describes the competition of different cell species for this HCO 3 - , a nutrient, as well as its uptake and utilization for cell production. Two microalgae species, i.e. Dunaliella salina and Nannochloropsis oculata, were cultured individually and in a competition situation under different atmospheric CO 2 conditions. It is shown that this novel model's predictions of biomass production are in very good agreement with the experimental flow cytometry results. After model validation, it has been applied to long-term prediction of phytoplankton generation. These investigations were motivated by the question whether or not cell production slows down as cultures grow. This is of relevance as a reduced cell production rate means that the increase in a culture's CO 2 -sinking capacity slows down as well. One implication resulting from this is that an increase in

  9. On the use of selective environments in microalgal cultivation

    NARCIS (Netherlands)

    Mooij, P.R.

    2016-01-01

    This thesis deals with selective environments in microalgal cultivation. As explained in Chapter 1 microalgae have changed the course of life on Earth dramatically by performing oxygenic photosynthesis. In oxygenic photosynthesis electrons from water are used to reduce carbon dioxide to

  10. Microalgal Cultivation in Secondary Effluent: Recent Developments and Future Work

    Directory of Open Access Journals (Sweden)

    Junping Lv

    2017-01-01

    Full Text Available Eutrophication of water catchments and the greenhouse effect are major challenges in developing the global economy in the near future. Secondary effluents, containing high amounts of nitrogen and phosphorus, need further treatment before being discharged into receiving water bodies. At the same time, new environmentally friendly energy sources need to be developed. Integrating microalgal cultivation for the production of biodiesel feedstock with the treatment of secondary effluent is one way of addressing both issues. This article provides a comprehensive review of the latest progress in microalgal cultivation in secondary effluent to remove pollutants and accumulate lipids. Researchers have discovered that microalgae remove nitrogen and phosphorus effectively from secondary effluent, accumulating biomass and lipids in the process. Immobilization of appropriate microalgae, and establishing a consortium of microalgae and/or bacteria, were both found to be feasible ways to enhance pollutant removal and lipid production. Demonstrations of pilot-scale microalgal cultures in secondary effluent have also taken place. However there is still much work to be done in improving pollutants removal, biomass production, and lipid accumulation in secondary effluent. This includes screening microalgae, constructing the consortium, making use of flue gas and nitrogen, developing technologies related to microalgal harvesting, and using lipid-extracted algal residues (LEA.

  11. Mycosporine-like amino acids are multifunctional molecules in sea hares and their marine community

    Science.gov (United States)

    Kicklighter, Cynthia E.; Kamio, Michiya; Nguyen, Linh; Germann, Markus W.; Derby, Charles D.

    2011-01-01

    Molecules of keystone significance are relatively rare, yet mediate a variety of interactions between organisms. They influence the distribution and abundance of species, the transfer of energy across multiple trophic levels, and thus they play significant roles in structuring ecosystems. Despite their potential importance in facilitating our understanding of ecological systems, only three molecules thus far have been proposed as molecules of keystone significance: saxitoxin and dimethyl sulfide in marine communities and tetrodotoxin in riparian communities. In the course of studying the neuroecology of chemical defenses, we identified three mycosporine-like amino acids (MAAs)—N-ethanol palythine (= asterina-330), N-isopropanol palythine (= aplysiapalythine A), and N-ethyl palythine (= aplysiapalythine B)—as intraspecific alarm cues for sea hares (Aplysia californica). These alarm cues are released in the ink secretion of sea hares and cause avoidance behaviors in neighboring conspecifics. Further, we show that these three bioactive MAAs, two [aplysiapalythine A (APA) and -B (APB)] being previously unknown molecules, are present in the algal diet of sea hares and are concentrated in their defensive secretion as well as in their skin. MAAs are known to be produced by algae, fungi, and cyanobacteria and are acquired by many aquatic animals through trophic interactions. MAAs are widely used as sunscreens, among other uses, but sea hares modify their function to serve a previously undocumented role, as intraspecific chemical cues. Our findings highlight the multifunctionality of MAAs and their role in ecological connectivity, suggesting that they may function as molecules of keystone significance in marine ecosystems. PMID:21709250

  12. Assessing the state of pelagic fish communities within an ecosystem approach and the European Marine Strategy Framework Directive

    DEFF Research Database (Denmark)

    Shephard, Samuel; Rindorf, Anna; Dickey-Collas, Mark

    2014-01-01

    Pelagic fish are key elements in marine foodwebs and thus comprise an important part of overall ecosystem health. We develop a suite of ecological indicators that track pelagic fish community state and evaluate state of specific objectives against Good Environmental Status (GES) criteria. Indicator...

  13. Community composition, structure, and interrelationships in the marine intertidal Endocladia muricata – Balanus glandula association in Monterey Bay, California

    NARCIS (Netherlands)

    Glynn, Peter W.

    1965-01-01

    Studies of the community composition, structure and species interrelationships of the Endocladia-Balanus association were carried out on the rocky shores at the Hopkins Marine Station, Pacific Grove, California, over the period 1959—1961. The organisms making up this biotic association form a

  14. The radiological exposure of the population of the European Community from radioactivity in North European marine waters Project 'Marina'

    International Nuclear Information System (INIS)

    1990-01-01

    Project Marina was set up by the Commission of the European Communities in 1985 to look at the radiological impact of radionuclides, both natural and anthropogenic, in northern European marine waters. This paper is a summary of project Marina's work and its conclusions

  15. Differences in composition of shallow-water marine benthic communities associated with two ophiolitic rock substrata

    Science.gov (United States)

    Bavestrello, Giorgio; Bo, Marzia; Betti, Federico; Canessa, Martina; Gaggero, Laura; Rindi, Fabio; Cattaneo-Vietti, Riccardo

    2018-01-01

    On marine rocky shores, several physical, chemical and biological processes operate to maintain the benthic assemblages' heterogeneity, but among the abiotic factors, the composition and texture of the rocky substrata have been only sporadically considered. However, biomineralogical studies have demonstrated an unsuspected ability of the benthic organisms to interact at different levels with rocky substrata. Therefore, the mineralogy of the substratum can affect the structure of benthic communities. To evaluate this hypothesis, the macrobenthic assemblages developed on two different ophiolitic rocks (serpentinites and metagabbros) in contact at a restricted stretch of the western Ligurian Riviera (western Mediterranean Sea), with identical environmental and climatic conditions, were analysed. Samplings were carried out at four bathymetric levels (+1m, 0m, -1m, and -3m respect to the mean sea level) and the analysis of the data evidenced differences in terms of species distribution and percent coverage. Algal communities growing on metagabbros were poorer in species richness and showed a much simpler structure when compared to the assemblages occurring on the serpentinites. The most widely distributed animal organism, the barnacle Chthamalus stellatus, was dominant on serpentinites, and virtually absent on metagabbros. Our results suggest a complex pattern of interactions between lithology and benthic organisms operating through processes of inhibition/facilitation related to the mineral properties of the substratum.

  16. Ammonia oxidation kinetics and temperature sensitivity of a natural marine community dominated by Archaea

    Science.gov (United States)

    Horak, Rachel E A; Qin, Wei; Schauer, Andy J; Armbrust, E Virginia; Ingalls, Anitra E; Moffett, James W; Stahl, David A; Devol, Allan H

    2013-01-01

    Archaeal ammonia oxidizers (AOAs) are increasingly recognized as prominent members of natural microbial assemblages. Evidence that links the presence of AOA with in situ ammonia oxidation activity is limited, and the abiotic factors that regulate the distribution of AOA natural assemblages are not well defined. We used quantitative PCR to enumerate amoA (encodes α-subunit of ammonia monooxygenase) abundances; AOA amoA gene copies greatly outnumbered ammonia-oxidizing bacteria and amoA transcripts were derived primarily from AOA throughout the water column of Hood Canal, Puget Sound, WA, USA. We generated a Michaelis–Menten kinetics curve for ammonia oxidation by the natural community and found that the measured Km of 98±14 nmol l−1 was close to that for cultivated AOA representative Nitrosopumilus maritimus SCM1. Temperature did not have a significant effect on ammonia oxidation rates for incubation temperatures ranging from 8 to 20 °C, which is within the temperature range for depths of measurable ammonia oxidation at the site. This study provides substantial evidence, through both amoA gene copies and transcript abundances and the kinetics response, that AOA are the dominant active ammonia oxidizers in this marine environment. We propose that future ammonia oxidation experiments use a Km for the natural community to better constrain ammonia oxidation rates determined with the commonly used 15NH4+ dilution technique. PMID:23657360

  17. Carbon Stored on Seagrass Community in Marine Nature Tourism Park of Kotania Bay, Western Seram, Indonesia

    Directory of Open Access Journals (Sweden)

    Mintje Wawo

    2014-04-01

    Full Text Available Currently, the function of seagrass community as carbon storage has been discussed in line with “blue carbon” function of that seagrass has. Seagrass bed are a very valuable coastal ecosystem, however, seagrass bed is threatened if compared to other coastal ecosystems, such as mangroves and coral reefs. The threatened seagrass experienced also contributes to its capacity in absorbing CO2 emission from greenhouse gasses such as CO2 emission Temporal estimation shows that CO2 emission will increase in the coming decade. On the other side, efforts to decrease climate change can be influenced by the existence of seagrass. Informations about existence of seagrass as carbon storage are still very rare or limited. This study was aimed to estimate carbon storage on seagrass community in Marine Nature Tourism Park of Kotania Bay Area, Western Seram, Maluku Province. The quadrat transect method of 0.25 m2 for each plot was used to collect seagrass existence. The content of carbon in the sample of dry biomass of seagrass was analyzed in the laboratory using Walkley & Black method. The results showed that total carbon stored was higher in both Osi and Burung Islands of Kotania Bay than other studied areas (Buntal and Tatumbu Islands, Marsegu Island, Barnusang Peninsula, Loupessy and Tamanjaya Village. The average carbon stored in Kotania Bay waters was 2.385 Mg C ha-1, whereas the total of carbon stored was 2054.4967 Mg C.

  18. Impact of Anthracene Exposure on Bacterial Community Composition and Function in an Egyptian Marine Environment

    International Nuclear Information System (INIS)

    Zakaria, A.E.M.; Lappin-Scott, H.

    2013-01-01

    The application of bioremediation technology for pollution treatment requires more knowledge about how do microbial communities respond to pollutant exposure. The main goals of this study are to investigate the behavior of natural bacterial microflora of Suez Gulf (SGM) in response to exposure to different concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) for different periods. In this study, anthracene, as a model of (PAHs) was added in different concentrations, (30,150 and 500 ppm) to fertilized Suez Gulf water in shaking microcosms to examine the possible shifts in bacterial community composition and function. Changes in bacterial community composition was followed up after different periods of exposure (0, 6, 12, and 18) days to the above mentioned concentrations of anthracene by profiling the amplified product of 16S rDNA via denaturing gradient gel electrophoresis (DGGE) of SGM in treated microcosm separately. DGGE profiles revealed remarkable changes in diversity due to exposure concentration and duration to anthracene. A diverse relationship between anthracene concentration and bacterial diversity was detected. On the other hand, changes in community function were determined by testing the biodegradation capabilities of the consortia after different exposures separately in microcosms containing 50 ppm of anthracene for 14 days. The remaining anthracene was extracted and monitored by high performance liquid chromatography (HPLC) and DGGE profiles of amplified 16S rDNA extracted from parallel biodegradation microcosms were examined to indicate the effects of pre-exposure to different concentrations for different periods to PAHs on the bacterial community compositions. The results confirm that the long term effects of pre exposure to high concentrations of PAH on the bacterial community composition, suggesting that that some organisms can be used as a bio marker indicating the exposures of the marine environment to high concentrations of PAHs. HPLC

  19. Shared Physiological and Molecular Responses in Marine Fish and Invertebrates to Environmental Hypoxia: Potential Biomarkers of Adverse Impacts on Marine Communities

    Science.gov (United States)

    Thomas, P.; Rahman, S.

    2016-02-01

    Knowledge of the effects of environmental exposure to hypoxia (dissolved oxygen: reproduction, growth and metabolism in both fish and invertebrates is essential for accurate predictions of its chronic impacts on marine communities. Marked disruption of reproduction and its endocrine control was observed in Atlantic croaker collected from the hypoxic region in the northern Gulf of Mexico. Recent research has shown that growth and its physiological upregulation is also impaired in hypoxia-exposed marine fish. Expression of insulin-like growth factor (IGF) binding protein (IGFBP), which inhibits growth, was increased in croaker livers, whereas plasma levels of IGF, the primary regulator of growth, were decreased in snapper after hypoxia exposure. In addition, hypoxia inducible factor-1 (HIF-1), which regulates changes in metabolism during adaptation to hypoxia, was upregulated in croaker collected from hypoxic environments. Interestingly, similar changes in the expression of IGFBP and HIF-1 have been found in marine crustaceans after hypoxia exposure, suggesting these responses to hypoxia are common to marine fish and invertebrates. Preliminary field studies indicate that hypoxia exposure also causes epigenetic modifications, including increases in global DNA methylation, and that these epigenetic changes can influence reproduction and growth in croaker. Epigenetic modifications can be passed to offspring and persist in future generations no longer exposed to an environmental stressor further aggravating its long-term adverse impacts on population abundance and delaying recovery. The growing availability of complete invertebrate genomes and high-throughput DNA sequencing indicates similar epigenetic studies can now be conducted with marine invertebrates. Collectively, the results indicate that environmental hypoxia exposure disrupts major physiological functions in fish and invertebrates critical for maintenance of their populations.

  20. Molecular Techniques Revealed Highly Diverse Microbial Communities in Natural Marine Biofilms on Polystyrene Dishes for Invertebrate Larval Settlement

    KAUST Repository

    Lee, On On

    2014-01-09

    Biofilm microbial communities play an important role in the larval settlement response of marine invertebrates. However, the underlying mechanism has yet to be resolved, mainly because of the uncertainties in characterizing members in the communities using traditional 16S rRNA gene-based molecular methods and in identifying the chemical signals involved. In this study, pyrosequencing was used to characterize the bacterial communities in intertidal and subtidal marine biofilms developed during two seasons. We revealed highly diverse biofilm bacterial communities that varied with season and tidal level. Over 3,000 operational taxonomic units with estimates of up to 8,000 species were recovered in a biofilm sample, which is by far the highest number recorded in subtropical marine biofilms. Nineteen phyla were found, of which Cyanobacteria and Proteobacteria were the most dominant one in the intertidal and subtidal biofilms, respectively. Apart from these, Actinobacteria, Bacteroidetes, and Planctomycetes were the major groups recovered in both intertidal and subtidal biofilms, although their relative abundance varied among samples. Full-length 16S rRNA gene clone libraries were constructed for the four biofilm samples and showed similar bacterial compositions at the phylum level to those revealed by pyrosequencing. Laboratory assays confirmed that cyrids of the barnacle Balanus amphitrite preferred to settle on the intertidal rather than subtidal biofilms. This preference was independent of the biofilm bacterial density or biomass but was probably related to the biofilm community structure, particularly, the Proteobacterial and Cyanobacterial groups. © 2014 Springer Science+Business Media New York.

  1. Biofouling community composition across a range of environmental conditions and geographical locations suitable for floating marine renewable energy generation.

    Science.gov (United States)

    Macleod, Adrian K; Stanley, Michele S; Day, John G; Cook, Elizabeth J

    2016-01-01

    Knowledge of biofouling typical of marine structures is essential for engineers to define appropriate loading criteria in addition to informing other stakeholders about the ecological implications of creating novel artificial environments. There is a lack of information regarding biofouling community composition (including weight and density characteristics) on floating structures associated with future marine renewable energy generation technologies. A network of navigation buoys were identified across a range of geographical areas, environmental conditions (tidal flow speed, temperature and salinity), and deployment durations suitable for future developments. Despite the perceived importance of environmental and temporal factors, geographical location explained the greatest proportion of the observed variation in community composition, emphasising the importance of considering geography when assessing the impact of biofouling on device functioning and associated ecology. The principal taxa associated with variation in biofouling community composition were mussels (Mytilus edulis), which were also important when determining loading criteria.

  2. Experimental Warming Decreases the Average Size and Nucleic Acid Content of Marine Bacterial Communities

    KAUST Repository

    Huete-Stauffer, Tamara M.; Arandia-Gorostidi, Nestor; Alonso-Sá ez, Laura; Moran, Xose Anxelu G.

    2016-01-01

    Organism size reduction with increasing temperature has been suggested as a universal response to global warming. Since genome size is usually correlated to cell size, reduction of genome size in unicells could be a parallel outcome of warming at ecological and evolutionary time scales. In this study, the short-term response of cell size and nucleic acid content of coastal marine prokaryotic communities to temperature was studied over a full annual cycle at a NE Atlantic temperate site. We used flow cytometry and experimental warming incubations, spanning a 6°C range, to analyze the hypothesized reduction with temperature in the size of the widespread flow cytometric bacterial groups of high and low nucleic acid content (HNA and LNA bacteria, respectively). Our results showed decreases in size in response to experimental warming, which were more marked in 0.8 μm pre-filtered treatment rather than in the whole community treatment, thus excluding the role of protistan grazers in our findings. Interestingly, a significant effect of temperature on reducing the average nucleic acid content (NAC) of prokaryotic cells in the communities was also observed. Cell size and nucleic acid decrease with temperature were correlated, showing a common mean decrease of 0.4% per °C. The usually larger HNA bacteria consistently showed a greater reduction in cell and NAC compared with their LNA counterparts, especially during the spring phytoplankton bloom period associated to maximum bacterial growth rates in response to nutrient availability. Our results show that the already smallest planktonic microbes, yet with key roles in global biogeochemical cycling, are likely undergoing important structural shrinkage in response to rising temperatures.

  3. Experimental Warming Decreases the Average Size and Nucleic Acid Content of Marine Bacterial Communities

    KAUST Repository

    Huete-Stauffer, Tamara M.

    2016-05-23

    Organism size reduction with increasing temperature has been suggested as a universal response to global warming. Since genome size is usually correlated to cell size, reduction of genome size in unicells could be a parallel outcome of warming at ecological and evolutionary time scales. In this study, the short-term response of cell size and nucleic acid content of coastal marine prokaryotic communities to temperature was studied over a full annual cycle at a NE Atlantic temperate site. We used flow cytometry and experimental warming incubations, spanning a 6°C range, to analyze the hypothesized reduction with temperature in the size of the widespread flow cytometric bacterial groups of high and low nucleic acid content (HNA and LNA bacteria, respectively). Our results showed decreases in size in response to experimental warming, which were more marked in 0.8 μm pre-filtered treatment rather than in the whole community treatment, thus excluding the role of protistan grazers in our findings. Interestingly, a significant effect of temperature on reducing the average nucleic acid content (NAC) of prokaryotic cells in the communities was also observed. Cell size and nucleic acid decrease with temperature were correlated, showing a common mean decrease of 0.4% per °C. The usually larger HNA bacteria consistently showed a greater reduction in cell and NAC compared with their LNA counterparts, especially during the spring phytoplankton bloom period associated to maximum bacterial growth rates in response to nutrient availability. Our results show that the already smallest planktonic microbes, yet with key roles in global biogeochemical cycling, are likely undergoing important structural shrinkage in response to rising temperatures.

  4. Basin-scale seasonal changes in marine free-living bacterioplankton community in the Ofunato Bay

    KAUST Repository

    Reza, Md. Shaheed

    2018-04-26

    The Ofunato Bay in the northeastern Pacific Ocean area of Japan possesses the highest biodiversity of marine organisms in the world and has attracted much attention due to its economic and environmental importance. We report here a shotgun metagenomic analysis of the year-round variation in free-living bacterioplankton collected across the entire length of the bay. Phylogenetic differences among spring, summer, autumn and winter bacterioplankton suggested that members of Proteobacteria tended to decrease at high water temperatures and increase at low temperatures. It was revealed that Candidatus Pelagibacter varied seasonally, reaching as much as 60% of all sequences at the genus level in the surface waters during winter. This increase was more evident in the deeper waters, where they reached up to 75%. The relative abundance of Planktomarina also rose during winter and fell during summer. A significant component of the winter bacterioplankton community was Archaea (mainly represented by Nitrosopumilus), as their relative abundance was very low during spring and summer but high during winter. In contrast, Actinobacteria and Cyanobacteria appeared to be higher in abundance during high-temperature periods. It was also revealed that Bacteroidetes constituted a significant component of the summer bacterioplankton community, being the second largest bacterial phylum detected in the Ofunato Bay. Its members, notably Polaribacter and Flavobacterium, were found to be high in abundance during spring and summer, particularly in the surface waters. Principal component analysis and hierarchal clustering analyses showed that the bacterial communities in the Ofunato Bay changed seasonally, likely caused by the levels of organic matter, which would be deeply mixed with surface runoff in the winter.

  5. Deep-Subsurface Marine Methane Hydrate Microbial Communities: Who's There and What Are They Doing?

    Science.gov (United States)

    Colwell, F.; Reed, D.; Fujita, Y.; Delwiche, M.; Blackwelder, D.; Uchida, T.; Fujii, T.; Lu, H.

    2001-12-01

    Natural gas hydrates are crystalline deposits of freshwater and primarily methane. They are estimated to represent a potentially vast reservoir of energy. Relatively little is known regarding microbial communities surrounding deep [>100 meters below sea floor (mbsf)] hydrate-bearing sediments. Deep sediment cores were collected in zones above, within, and below the hydrate bearing strata in an accretionary prism off the coast of Japan. Microorganisms were characterized using cultivation- and non-cultivation-based microbiological techniques to better understand the role that they play in the production and distribution of methane in gas hydrates. Direct counts show cell density at 105 cells/g throughout the hydrate strata. Lipid and 16S rDNA analyses indicate that diverse bacterial and archaeal microorganisms are represented throughout the strata. Acetate and hydrogen were utilized as an energy source for methane-producing microorganisms from each sediment depth. Although the methanogenic biomarker coenzyme M was not present above the detection limit in any of the samples, cloning and characterization of amplified 16S ribosomal RNA genes indicated the presence of methanogenic microorganisms related to the Methanobacteriales and Methanococcales. In addition, archaeal clones closely related to the hyperthermophilic Pyrodictiales were detected. Analysis of eubacterial clones indicated a more diverse eubacterial community compared to the archaea, including members from the groups of cyanobacteria, proteobacteria, gram positive bacteria, and flexibacter-cytophaga-bacteriodes. This study suggests that the diversity of microbial communities associated with the presence of methane in gas hydrate-rich deep marine sediments is greater than previously estimated.

  6. Modelling of green microalgal growth and algal storage processes using wastewater resources

    DEFF Research Database (Denmark)

    Wágner, Dorottya Sarolta; Plósz, Benedek G.; Valverde Pérez, Borja

    2017-01-01

    Recent research focuses on the recovery of nutrients, water and energy from wastewater. Microalgal cultivation on wastewater resources is considered as a more sustainable means to produce fertilizers or biofuels. Innovative systems that incorporate microalgal cultivation into conventional wastewa...... have been developed according to the activated sludge modelling (ASM) framework to facilitate the integration with existing modelling frameworks in water treatment. This chapter presents in detail the recently developed ASM-A biokinetic green microalgal process model. The model includes...

  7. Biodiversity characterisation and hydrodynamic consequences of marine fouling communities on marine renewable energy infrastructure in the Orkney Islands Archipelago, Scotland, UK.

    Science.gov (United States)

    Want, Andrew; Crawford, Rebecca; Kakkonen, Jenni; Kiddie, Greg; Miller, Susan; Harris, Robert E; Porter, Joanne S

    2017-08-01

    As part of ongoing commitments to produce electricity from renewable energy sources in Scotland, Orkney waters have been targeted for potential large-scale deployment of wave and tidal energy converting devices. Orkney has a well-developed infrastructure supporting the marine energy industry; recently enhanced by the construction of additional piers. A major concern to marine industries is biofouling on submerged structures, including energy converters and measurement instrumentation. In this study, the marine energy infrastructure and instrumentation were surveyed to characterise the biofouling. Fouling communities varied between deployment habitats; key species were identified allowing recommendations for scheduling device maintenance and preventing spread of invasive organisms. A method to measure the impact of biofouling on hydrodynamic response is described and applied to data from a wave-monitoring buoy deployed at a test site in Orkney. The results are discussed in relation to the accuracy of the measurement resources for power generation. Further applications are suggested for future testing in other scenarios, including tidal energy.

  8. Microalgal Cultivation in Treating Liquid Digestate from Biogas Systems.

    Science.gov (United States)

    Xia, Ao; Murphy, Jerry D

    2016-04-01

    Biogas production via anaerobic digestion (AD) has rapidly developed in recent years. In addition to biogas, digestate is an important byproduct. Liquid digestate is the major fraction of digestate and may contain high levels of ammonia nitrogen. Traditional processing technologies (such as land application) require significant energy inputs and raise environmental risks (such as eutrophication). Alternatively, microalgae can efficiently remove the nutrients from digestate while producing high-value biomass that can be used for the production of biochemicals and biofuels. Both inorganic and organic carbon sources derived from biogas production can significantly improve microalgal production. Land requirement for microalgal cultivation is estimated as 3% of traditional direct land application of digestate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Follow-up trends of parasite community alteration in a marine fish after the Prestige oil-spill: Shifting baselines?

    International Nuclear Information System (INIS)

    Perez-del-Olmo, A.; Montero, F.E.; Raga, J.A.; Fernandez, M.; Kostadinova, A.

    2009-01-01

    This study evaluates the follow-up trends in the composition and structure of the parasite communities in the marine sparid Boops boops after the Prestige oil-spill. A total of 400 fish comprising 11 seasonal samples was analyzed from three impacted localities on the Atlantic coast of Spain. A large number of parasite species was recovered only after the spill thus suggesting a substantial alteration of the marine food webs. Post-spill communities exhibited higher richness and abundance due to the significant changes in the abundance of the common species, the latter indicating accelerated parasite transmission rates. Multivariate analyses at two nested scales detected a directional trend in parasite community succession towards the pre-spill situation, however, with no full support for community recovery. The state of parasite communities in 2005-2006 may provide the new baseline data which can serve as a framework for quantifying the impact of potential future spills in the region. - Prestige oil-spill impact on parasite communities in the sparid fish B. boops

  10. A novel microalgal system for energy production with nitrogen cycling

    Energy Technology Data Exchange (ETDEWEB)

    Minowa, T.; Sawayama, S. [National Institute for Resources and Environment, Tsukuba (Japan)

    1999-08-01

    A microalga, Chlorella vulgaris, could grow in the recovered solution from the low temperature catalytic gasification of itself, by which methane rich fuel gas was obtained. All nitrogen in the microalga was converted to ammonia during the gasification, and the recovered solution, in which ammonia was dissolved, could be used as nitrogen nutrient. The result of the energy evaluation indicated that the novel microalgal system for energy production with nitrogen cycling could be created. 9 refs., 3 tabs.

  11. Microbial communities and bioactive compounds in marine sponges of the family irciniidae-a review.

    Science.gov (United States)

    Hardoim, Cristiane C P; Costa, Rodrigo

    2014-09-30

    Marine sponges harbour complex microbial communities of ecological and biotechnological importance. Here, we propose the application of the widespread sponge family Irciniidae as an appropriate model in microbiology and biochemistry research. Half a gram of one Irciniidae specimen hosts hundreds of bacterial species-the vast majority of which are difficult to cultivate-and dozens of fungal and archaeal species. The structure of these symbiont assemblages is shaped by the sponge host and is highly stable over space and time. Two types of quorum-sensing molecules have been detected in these animals, hinting at microbe-microbe and host-microbe signalling being important processes governing the dynamics of the Irciniidae holobiont. Irciniids are vulnerable to disease outbreaks, and concerns have emerged about their conservation in a changing climate. They are nevertheless amenable to mariculture and laboratory maintenance, being attractive targets for metabolite harvesting and experimental biology endeavours. Several bioactive terpenoids and polyketides have been retrieved from Irciniidae sponges, but the actual producer (host or symbiont) of these compounds has rarely been clarified. To tackle this, and further pertinent questions concerning the functioning, resilience and physiology of these organisms, truly multi-layered approaches integrating cutting-edge microbiology, biochemistry, genetics and zoology research are needed.

  12. Microbial Communities and Bioactive Compounds in Marine Sponges of the Family Irciniidae—A Review

    Directory of Open Access Journals (Sweden)

    Cristiane C. P. Hardoim

    2014-09-01

    Full Text Available Marine sponges harbour complex microbial communities of ecological and biotechnological importance. Here, we propose the application of the widespread sponge family Irciniidae as an appropriate model in microbiology and biochemistry research. Half a gram of one Irciniidae specimen hosts hundreds of bacterial species—the vast majority of which are difficult to cultivate—and dozens of fungal and archaeal species. The structure of these symbiont assemblages is shaped by the sponge host and is highly stable over space and time. Two types of quorum-sensing molecules have been detected in these animals, hinting at microbe-microbe and host-microbe signalling being important processes governing the dynamics of the Irciniidae holobiont. Irciniids are vulnerable to disease outbreaks, and concerns have emerged about their conservation in a changing climate. They are nevertheless amenable to mariculture and laboratory maintenance, being attractive targets for metabolite harvesting and experimental biology endeavours. Several bioactive terpenoids and polyketides have been retrieved from Irciniidae sponges, but the actual producer (host or symbiont of these compounds has rarely been clarified. To tackle this, and further pertinent questions concerning the functioning, resilience and physiology of these organisms, truly multi-layered approaches integrating cutting-edge microbiology, biochemistry, genetics and zoology research are needed.

  13. Antimicrobial activity of heterotrophic bacterial communities from the marine sponge Erylus discophorus (Astrophorida, Geodiidae.

    Directory of Open Access Journals (Sweden)

    Ana Patrícia Graça

    Full Text Available Heterotrophic bacteria associated with two specimens of the marine sponge Erylus discophorus were screened for their capacity to produce bioactive compounds against a panel of human pathogens (Staphylococcus aureus wild type and methicillin-resistant S. aureus (MRSA, Bacillus subtilis, Pseudomonas aeruginosa, Acinetobacter baumanii, Candida albicans and Aspergillus fumigatus, fish pathogen (Aliivibrio fischeri and environmentally relevant bacteria (Vibrio harveyi. The sponges were collected in Berlengas Islands, Portugal. Of the 212 isolated heterotrophic bacteria belonging to Alpha- and Gammaproteobacteria, Actinobacteria and Firmicutes, 31% produced antimicrobial metabolites. Bioactivity was found against both Gram positive and Gram negative and clinically and environmentally relevant target microorganisms. Bioactivity was found mainly against B. subtilis and some bioactivity against S. aureus MRSA, V. harveyi and A. fisheri. No antifungal activity was detected. The three most bioactive genera were Pseudovibrio (47.0%, Vibrio (22.7% and Bacillus (7.6%. Other less bioactive genera were Labrenzia, Acinetobacter, Microbulbifer, Pseudomonas, Gordonia, Microbacterium, Micrococcus and Mycobacterium, Paenibacillus and Staphylococcus. The search of polyketide I synthases (PKS-I and nonribosomal peptide synthetases (NRPSs genes in 59 of the bioactive bacteria suggested the presence of PKS-I in 12 strains, NRPS in 3 strains and both genes in 3 strains. Our results show the potential of the bacterial community associated with Erylus discophorus sponges as producers of bioactive compounds.

  14. Complex communities of small protists and unexpected occurrence of typical marine lineages in shallow freshwater systems.

    Science.gov (United States)

    Simon, Marianne; Jardillier, Ludwig; Deschamps, Philippe; Moreira, David; Restoux, Gwendal; Bertolino, Paola; López-García, Purificación

    2015-10-01

    Although inland water bodies are more heterogeneous and sensitive to environmental variation than oceans, the diversity of small protists in these ecosystems is much less well known. Some molecular surveys of lakes exist, but little information is available from smaller, shallower and often ephemeral freshwater systems, despite their global distribution and ecological importance. We carried out a comparative study based on massive pyrosequencing of amplified 18S rRNA gene fragments of protists in the 0.2-5 μm size range in one brook and four shallow ponds located in the Natural Regional Park of the Chevreuse Valley, France. Our study revealed a wide diversity of small protists, with 812 stringently defined operational taxonomic units (OTUs) belonging to the recognized eukaryotic supergroups (SAR--Stramenopiles, Alveolata, Rhizaria--Archaeplastida, Excavata, Amoebozoa, Opisthokonta) and to groups of unresolved phylogenetic position (Cryptophyta, Haptophyta, Centrohelida, Katablepharida, Telonemida, Apusozoa). Some OTUs represented deep-branching lineages (Cryptomycota, Aphelida, Colpodellida, Tremulida, clade-10 Cercozoa, HAP-1 Haptophyta). We identified several lineages previously thought to be marine including, in addition to MAST-2 and MAST-12, already detected in freshwater, MAST-3 and possibly MAST-6. Protist community structures were different in the five ecosystems. These differences did not correlate with geographical distances, but seemed to be influenced by environmental parameters. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. FY1995 microalgal biotechnology for recycling of pollutants; 1995 nendo tayona sorui kino wo kiban to suru seibutsuken busshitsu junkangta sogo saishigenka gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The objectives are 1) development of biological processes needed for the treatment of pollutants and the conversion of resulting biomass to value added products such as energy and fine chemicals, and 2) development of techniques for monitoring of both biological and chemical hazards associated with process operation. We developed a microalgal system for simultaneous removal of CO{sub 2}/NO{sub x} from flue gas, as well as an electro-osmotic method for recovery of microalgal cells. A strategy for effective culturing of photoautotrophic cells in photobioreactors was also proposed. We utilized waste algal biomass to produce biosurfactants, and studied about structure-function relationship of lipopeptide biosurfactants. As an energy product, H{sub 2} was produced via lactic acid fermentation of algal biomass. Physiology of marine phytoplankton was also studied in relation to the future mass production of microalgal biomass. A rapid monitoring of microbial populations was possible by using fluorescent probes. An enzyme immunosorbent assay system specific to fish metallothionein was established for the assessment of aquatic environmental pollution. Human herpesvirus latent infection was effectively applied to biological assay of environmental hygiene. (NEDO)

  16. Kinetics of Chlorella protothecoides microalgal oil using base catalyst

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar

    2016-09-01

    Full Text Available Due to continuous diminishing of fossil fuel resources and emission of greenhouse gases, the search for alternative fuels such as biodiesel and bioethanol has become inevitable. Biodiesel, also known as fatty acid methyl or ethyl ester, has emerged as a substitute for diesel because of similar fuel properties. Presently, biodiesel is produced from edible, non-edible and microalgal oil. Chlorella protothecoides (lipid content 14.6–57.8% is being investigated as the potential microalgae species owing to high oil content, less land area required for cultivation and faster growth rate. The present investigation shows the results of the kinetics of transesterification of C. protothecoides microalgal oil carried out at optimum conditions of catalyst concentration, reaction temperature, molar ratio and reaction time. The percentage of methyl ester yield is the only parameter chosen to carry out the optimum parameter and the kinetics of transesterification. The reaction rate constant was to be 0.0618 min−1. Furthermore, microalgal biodiesel is characterized for physico-chemical properties that are found to meet American (ASTM D6751 and Indian (IS 15607 standards, especially in cold flow properties and stability of conventional biodiesel.

  17. Do plastic particles affect microalgal photosynthesis and growth?

    Science.gov (United States)

    Sjollema, Sascha B; Redondo-Hasselerharm, Paula; Leslie, Heather A; Kraak, Michiel H S; Vethaak, A Dick

    2016-01-01

    The unbridled increase in plastic pollution of the world's oceans raises concerns about potential effects these materials may have on microalgae, which are primary producers at the basis of the food chain and a major global source of oxygen. Our current understanding about the potential modes and mechanisms of toxic action that plastic particles exert on microalgae is extremely limited. How effects might vary with particle size and the physico-chemical properties of the specific plastic material in question are equally unelucidated, but may hold clues to how toxicity, if observed, is exerted. In this study we selected polystyrene particles, both negatively charged and uncharged, and three different sizes (0.05, 0.5 and 6μm) for testing the effects of size and material properties. Microalgae were exposed to different polystyrene particle sizes and surface charges for 72h. Effects on microalgal photosynthesis and growth were determined by pulse amplitude modulation fluorometry and flow cytometry, respectively. None of the treatments tested in these experiments had an effect on microalgal photosynthesis. Microalgal growth was negatively affected (up to 45%) by uncharged polystyrene particles, but only at high concentrations (250mg/L). Additionally, these adverse effects were demonstrated to increase with decreasing particle size. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Physiology limits commercially viable photoautotrophic production of microalgal biofuels.

    Science.gov (United States)

    Kenny, Philip; Flynn, Kevin J

    2017-01-01

    Algal biofuels have been offered as an alternative to fossil fuels, based on claims that microalgae can provide a highly productive source of compounds as feedstocks for sustainable transport fuels. Life cycle analyses identify algal productivity as a critical factor affecting commercial and environmental viability. Here, we use mechanistic modelling of the biological processes driving microalgal growth to explore optimal production scenarios in an industrial setting, enabling us to quantify limits to algal biofuels potential. We demonstrate how physiological and operational trade-offs combine to restrict the potential for solar-powered algal-biodiesel production in open ponds to a ceiling of ca. 8000 L ha -1 year -1 . For industrial-scale operations, practical considerations limit production to ca. 6000 L ha -1 year -1 . According to published economic models and life cycle analyses, such production rates cannot support long-term viable commercialisation of solar-powered cultivation of natural microalgae strains exclusively as feedstock for biofuels. The commercial viability of microalgal biofuels depends critically upon limitations in microalgal physiology (primarily in rates of C-fixation); we discuss the scope for addressing this bottleneck concluding that even deployment of genetically modified microalgae with radically enhanced characteristics would leave a very significant logistical if not financial burden.

  19. The response of microalgal biomass and community composition to ...

    African Journals Online (AJOL)

    2011-06-06

    Jun 6, 2011 ... Estuary (33º 43' S; 25º 51' E), and is permanently open to the sea (Fig. 1). .... visualised using the Imaplan V 2.06 image analysis programme. (IMATEC ... using the Zeiss IM 35 inverted microscope at 630x magnifica- tion.

  20. Energy Gradients Structure Microbial Communities Across Sediment Horizons in Deep Marine Sediments of the South China Sea

    Directory of Open Access Journals (Sweden)

    Michael F. Graw

    2018-04-01

    Full Text Available The deep marine subsurface is a heterogeneous environment in which the assembly of microbial communities is thought to be controlled by a combination of organic matter deposition, electron acceptor availability, and sedimentology. However, the relative importance of these factors in structuring microbial communities in marine sediments remains unclear. The South China Sea (SCS experiences significant variability in sedimentation across the basin and features discrete changes in sedimentology as a result of episodic deposition of turbidites and volcanic ashes within lithogenic clays and siliceous or calcareous ooze deposits throughout the basin's history. Deep subsurface microbial communities were recently sampled by the International Ocean Discovery Program (IODP at three locations in the SCS with sedimentation rates of 5, 12, and 20 cm per thousand years. Here, we used Illumina sequencing of the 16S ribosomal RNA gene to characterize deep subsurface microbial communities from distinct sediment types at these sites. Communities across all sites were dominated by several poorly characterized taxa implicated in organic matter degradation, including Atribacteria, Dehalococcoidia, and Aerophobetes. Sulfate-reducing bacteria comprised only 4% of the community across sulfate-bearing sediments from multiple cores and did not change in abundance in sediments from the methanogenic zone at the site with the lowest sedimentation rate. Microbial communities were significantly structured by sediment age and the availability of sulfate as an electron acceptor in pore waters. However, microbial communities demonstrated no partitioning based on the sediment type they inhabited. These results indicate that microbial communities in the SCS are structured by the availability of electron donors and acceptors rather than sedimentological characteristics.

  1. Energy Gradients Structure Microbial Communities Across Sediment Horizons in Deep Marine Sediments of the South China Sea

    Science.gov (United States)

    Graw, Michael F.; D'Angelo, Grace; Borchers, Matthew; Thurber, Andrew R.; Johnson, Joel E.; Zhang, Chuanlun; Liu, Haodong; Colwell, Frederick S.

    2018-01-01

    The deep marine subsurface is a heterogeneous environment in which the assembly of microbial communities is thought to be controlled by a combination of organic matter deposition, electron acceptor availability, and sedimentology. However, the relative importance of these factors in structuring microbial communities in marine sediments remains unclear. The South China Sea (SCS) experiences significant variability in sedimentation across the basin and features discrete changes in sedimentology as a result of episodic deposition of turbidites and volcanic ashes within lithogenic clays and siliceous or calcareous ooze deposits throughout the basin's history. Deep subsurface microbial communities were recently sampled by the International Ocean Discovery Program (IODP) at three locations in the SCS with sedimentation rates of 5, 12, and 20 cm per thousand years. Here, we used Illumina sequencing of the 16S ribosomal RNA gene to characterize deep subsurface microbial communities from distinct sediment types at these sites. Communities across all sites were dominated by several poorly characterized taxa implicated in organic matter degradation, including Atribacteria, Dehalococcoidia, and Aerophobetes. Sulfate-reducing bacteria comprised only 4% of the community across sulfate-bearing sediments from multiple cores and did not change in abundance in sediments from the methanogenic zone at the site with the lowest sedimentation rate. Microbial communities were significantly structured by sediment age and the availability of sulfate as an electron acceptor in pore waters. However, microbial communities demonstrated no partitioning based on the sediment type they inhabited. These results indicate that microbial communities in the SCS are structured by the availability of electron donors and acceptors rather than sedimentological characteristics. PMID:29696012

  2. Investigation of the marine communities of Midway Harbor and adjacent lagoon, Midway Atoll, Northwest Hawaiian Islands in 1998 (NODC Accession 0001098)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A survey of the marine communities of Midway Atoll harbor and surrounding lagoon was conducted at 12 sites from September 5 to 9, 1998. The primary focus of these...

  3. Salinity shifts in marine sediment: Importance of number of fluctuation rather than their intensities on bacterial denitrifying community.

    Science.gov (United States)

    Zaghmouri, Imen; Michotey, Valerie D; Armougom, Fabrice; Guasco, Sophie; Bonin, Patricia C

    2018-05-01

    The sensitivity of denitrifying community to salinity fluctuations was studied in microcosms filled with marine coastal sediments subjected to different salinity disturbances over time (sediment under frequent salinity changes vs sediment with "stable" salinity pattern). Upon short-term salinity shift, denitrification rate and denitrifiers abundance showed high resistance whatever the sediment origin is. Denitrifying community adapted to frequent salinity changes showed high resistance when salinity increases, with a dynamic nosZ relative expression level. Marine sediment denitrifying community, characterized by more stable pattern, was less resistant when salinity decreases. However, after two successive variations of salinity, it shifted toward the characteristic community of fluctuating conditions, with larger proportion of Pseudomonas-nosZ, exhibiting an increase of nosZ relative expression level. The impact of long-term salinity variation upon bacterial community was confirmed at ribosomal level with a higher percentage of Pseudomonas and lower proportion of nosZII clade genera. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Marine Microbial Gene Abundance and Community Composition in Response to Ocean Acidification and Elevated Temperature in Two Contrasting Coastal Marine Sediments

    Directory of Open Access Journals (Sweden)

    Ashleigh R. Currie

    2017-08-01

    Full Text Available Marine ecosystems are exposed to a range of human-induced climate stressors, in particular changing carbonate chemistry and elevated sea surface temperatures as a consequence of climate change. More research effort is needed to reduce uncertainties about the effects of global-scale warming and acidification for benthic microbial communities, which drive sedimentary biogeochemical cycles. In this research, mesocosm experiments were set up using muddy and sandy coastal sediments to investigate the independent and interactive effects of elevated carbon dioxide concentrations (750 ppm CO2 and elevated temperature (ambient +4°C on the abundance of taxonomic and functional microbial genes. Specific quantitative PCR primers were used to target archaeal, bacterial, and cyanobacterial/chloroplast 16S rRNA in both sediment types. Nitrogen cycling genes archaeal and bacterial ammonia monooxygenase (amoA and bacterial nitrite reductase (nirS were specifically targeted to identify changes in microbial gene abundance and potential impacts on nitrogen cycling. In muddy sediment, microbial gene abundance, including amoA and nirS genes, increased under elevated temperature and reduced under elevated CO2 after 28 days, accompanied by shifts in community composition. In contrast, the combined stressor treatment showed a non-additive effect with lower microbial gene abundance throughout the experiment. The response of microbial communities in the sandy sediment was less pronounced, with the most noticeable response seen in the archaeal gene abundances in response to environmental stressors over time. 16S rRNA genes (amoA and nirS were lower in abundance in the combined stressor treatments in sandy sediments. Our results indicated that marine benthic microorganisms, especially in muddy sediments, are susceptible to changes in ocean carbonate chemistry and seawater temperature, which ultimately may have an impact upon key benthic biogeochemical cycles.

  5. Effects on the function of three trophic levels in marine plankton communities under stress from the antifouling compound zinc pyrithione

    International Nuclear Information System (INIS)

    Hjorth, M.; Dahlloef, I.; Forbes, V.E.

    2006-01-01

    This study aimed to investigate functional responses of natural marine planktonic communities to stress from the antifouling compound zinc pyrithione (ZPT). Isotope labelling techniques ( 14 C) were applied to study bacterial incorporation of leucine, photosynthetic activity of phytoplankton and grazing of labelled prey by zooplankton communities for 6 days after exposures to nominal concentrations of 0, 5, 25, 50 nM ZPT in a mesocosm experiment in Isefjord, Denmark. Significant direct effects were visible on chlorophyll a concentrations, which decreased in all exposed communities, to between 48 and 36% of control concentrations on Day 3, 1 day after the last exposure. Phytoplankton activities were also significantly affected on Day 3 with activities between 9 and 26% of control levels, as was zooplankton activities in the 25 and 50 nM exposures. In the 50 nM exposure the total community zooplankton activity was reduced to 25 ± 4%, and per individual to 46 ± 11% of control levels. Bacterial communities showed positive indirect effects with high activities (up to 183 ± 40%) due to higher amounts of available substrate from algal death. Pollution induced community tolerance analyses performed on phytoplankton and bacterial communities at the end of the experiment indicated a development of increased tolerance for phytoplankton in the 50 nM exposed communities, whereas there were no changes in tolerance in the bacterial communities. Multivariate analysis of the integrated functional response by the plankton communities revealed a significant difference (p < 0.05) between exposed communities compared to controls in the first 3 days after last exposure and in the end of the experiment. The study provides evidence of diverse effects on the functions of marine plankton communities under stress from a pollutant. Direct effects lead to cascading indirect effects throughout the community, eventually causing different developments. Continuous exposure to ZPT could lead to

  6. Identification of an industrial microalgal strain for starch production in biorefinery context

    NARCIS (Netherlands)

    Gifuni, Imma; Olivieri, Giuseppe; Pollio, Antonino; Marzocchella, Antonio

    2018-01-01

    The recent trends in microalgal cultures are focused on the biorefinery of the biomass components. Some of them are not completely valorised, for example starch. Since there is a wide market for starch products in food and non-food industries, the exploitation of microalgal starch fractions could

  7. Quantification of microbial communities in subsurface marine sediments of the Black Sea and off Namibia

    Directory of Open Access Journals (Sweden)

    Axel eSchippers

    2012-01-01

    Full Text Available Organic-rich subsurface marine sediments were taken by gravity coring up to a depth of 10 meters below seafloor at six stations from the anoxic Black Sea and the Benguela upwelling system off Namibia during the research cruises R/V Meteor 72/5 and 76/1, respectively. The quantitative microbial community composition at various sediment depths was analyzed using total cell counting, CARD-FISH and quantitative real-time PCR (Q-PCR. Total cell counts decreased with depths from 109 – 1010 cells /mL at the sediment surface to 107 – 109 cells /mL below one meter depth. Based on CARD-FISH and Q-PCR analysis overall similar proportions of Bacteria and Archaea were determined. The down core quantitative distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes as well as functional genes involved in different biogeochemical processes was successfully revealed by Q-PCR. Crenarchaeota and the bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi were as highly abundant as Archaea and Bacteria, respectively. Less abundant but detectable in most of the samples in high gene copy numbers were Eukarya and the Fe(III- and Mn(IV-reducing bacterial group Geobacteriaceae (off Namibia as well as the functional genes cbbL encoding for the large subunit of Rubisco, the functional genes dsrA and aprA of sulfate-reducers and the gene mcrA of methanogens. Overall the high organic carbon content of the sediments goes along with high cell counts and high gene copy numbers, as well as an equal abundance of Bacteria and Archaea.

  8. Quantification of Microbial Communities in Subsurface Marine Sediments of the Black Sea and off Namibia.

    Science.gov (United States)

    Schippers, Axel; Kock, Dagmar; Höft, Carmen; Köweker, Gerrit; Siegert, Michael

    2012-01-01

    Organic-rich subsurface marine sediments were taken by gravity coring up to a depth of 10 m below seafloor at six stations from the anoxic Black Sea and the Benguela upwelling system off Namibia during the research cruises Meteor 72-5 and 76-1, respectively. The quantitative microbial community composition at various sediment depths was analyzed using total cell counting, catalyzed reporter deposition - fluorescence in situ hybridization (CARD-FISH) and quantitative real-time PCR (Q-PCR). Total cell counts decreased with depths from 10(9) to 10(10) cells/mL at the sediment surface to 10(7)-10(9) cells/mL below one meter depth. Based on CARD-FISH and Q-PCR analyses overall similar proportions of Bacteria and Archaea were found. The down-core distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes (16S and 18S rRNA) as well as functional genes involved in different biogeochemical processes was quantified using Q-PCR. Crenarchaeota and the bacterial candidate division JS-1 as well as the classes Anaerolineae and Caldilineae of the phylum Chloroflexi were highly abundant. Less abundant but detectable in most of the samples were Eukarya as well as the metal and sulfate-reducing Geobacteraceae (only in the Benguela upwelling influenced sediments). The functional genes cbbL, encoding for the large subunit of RuBisCO, the genes dsrA and aprA, indicative of sulfate-reducers as well as the mcrA gene of methanogens were detected in the Benguela upwelling and Black Sea sediments. Overall, the high organic carbon content of the sediments goes along with high cell counts and high gene copy numbers, as well as an equal abundance of Bacteria and Archaea.

  9. Marine Subsurface Microbial Communities Across a Hydrothermal Gradient in Okinawa Trough Sediments

    Science.gov (United States)

    Brandt, L. D.; Hser Wah Saw, J.; Ettema, T.; House, C. H.

    2015-12-01

    IODP Expedition 331 to the Okinawa backarc basin provided an opportunity to study the microbial stratigraphy within the sediments surrounding a hydrothermal vent. The Okinawa backarc basin is a sedimented region of the seafloor located on a continental margin, and also hosts a hydrothermal network within the subsurface. Site C0014 within the Iheya North hydrothermal field is located 450 m east of the active vent and has a surface temperature of 5°C with no evidence of hydrothermal alteration within the top 10 meters below sea floor (mbsf). Temperature increases with depth at an estimated rate of 3°C/m and transitions from non-hydrothermal margin sediments to a hydrothermally altered regime below 10 mbsf. In this study, we utilized deep 16S rRNA sequencing of DNA from IODP Expedition 331 Site C0014 sediment horizons in order to assess diversity throughout the sediment column as well as determine the potential limits of the biosphere. Analysis of the amplicon data shows a shift over 15 mbsf from a heterogeneous community of cosmopolitan marine subsurface taxa toward an archaeal-dominated community in the deepest horizons of the predicted biosphere. Notably, the phylum Chloroflexi represents a substantial taxon through most horizons, where it appears to be replaced below 10 mbsf by punctuations of thermophilic and methanotrophic Archaea and Miscellaneous Crenarchaeotic Group abundances. DNA from the aforementioned transition horizons was further analyzed using metagenomic sequencing. Preliminary taxonomic analysis of the metagenomic data agrees well with amplicon data in capturing the shift in relative abundance of Archaea increasing with depth. Additionally, reverse gyrase, a gene found exclusively in hyperthermophilic microorganisms, was recovered only in the metagenome of the deepest horizon. A BLAST search of this protein sequence against the GenBank non-redudnant protein database produced top hits with reverse gyrase from Thermococcus and Pyrococcus, which are

  10. Capturing Early Changes in the Marine Bacterial Community as a Result of Crude Oil Pollution in a Mesocosm Experiment.

    Science.gov (United States)

    Krolicka, Adriana; Boccadoro, Catherine; Nilsen, Mari Mæland; Baussant, Thierry

    2017-12-27

    The results of marine bacterial community succession from a short-term study of seawater incubations at 4°C to North Sea crude oil are presented herein. Oil was used alone (O) or in combination with a dispersant (OD). Marine bacterial communities resulting from these incubations were characterized by a fingerprinting analysis and pyrosequencing of the 16S rRNA gene with the aim of 1) revealing differences in bacterial communities between the control, O treatment, and OD treatment and 2) identifying the operational taxonomic units (OTUs) of early responders in order to define the bacterial gene markers of oil pollution for in situ monitoring.After an incubation for 1 d, the distribution of the individual ribotypes of bacterial communities in control and oil-treated (O and OD) tanks differed. Differences related to the structures of bacterial communities were observed at later stages of the incubation. Among the early responders identified (Pseudoalteromonas, Sulfitobacter, Vibrio, Pseudomonas, Glaciecola, Neptunomonas, Methylophaga, and Pseudofulvibacter), genera that utilize a disintegrated biomass or hydrocarbons as well as biosurfactant producers were detected. None of these genera included obligate hydrocarbonoclastic bacteria (OHCB). After an incubation for 1 d, the abundances of Glaciecola and Pseudofulvibacter were approximately 30-fold higher in the OD and O tanks than in the control tank. OTUs assigned to the Glaciecola genus were represented more in the OD tank, while those of Pseudofulvibacter were represented more in the O tank. We also found that 2 to 3% of the structural community shift originated from the bacterial community in the oil itself, with Polaribacter being a dominant bacterium.

  11. Genetic diversity and temporal variation of the marine Synechococcus community in the subtropical coastal waters of Hong Kong.

    Science.gov (United States)

    Jing, Hongmei; Zhang, Rui; Pointing, Stephen B; Liu, Hongbin; Qian, Peiyuan

    2009-03-01

    The phylogenetic diversity of the marine Synechococcus community in the subtropical coastal waters of Hong Kong, China, was examined through intergenic transcribed spacer clone libraries. All the sequences obtained fell within both marine cluster A (MC-A) and B (MC-B), with MC-A phylotypes dominating throughout the year. Distinct phylogenetic lineages specific to Hong Kong waters were detected from both MC-A and MC-B. The highest Synechococcus community diversity occurred in December, but the highest Synechococcus abundance occurred in August. On the other hand, both the abundance and diversity of Synechococcus showed a minimum in February. The remarkable seasonal variations of Synechococcus diversity observed were likely the result of the changes of hydrographic condition modulated by monsoons. Principal component analysis revealed that the in situ abiotic water characteristics, especially salinity and water turbidity, explained much of the variability of the marine Synechococcus population diversity in Hong Kong coastal waters. In addition, the temporal changes of Synechococcus abundance were largely driven by water temperature.

  12. Youth Science Ambassadors: Connecting Indigenous communities with Ocean Networks Canada tools to inspire future ocean scientists and marine resource managers

    Science.gov (United States)

    Pelz, M.; Hoeberechts, M.; Hale, C.; McLean, M. A.

    2017-12-01

    This presentation describes Ocean Networks Canada's (ONC) Youth Science Ambassador Program. The Youth Science Ambassadors are a growing network of youth in Canadian coastal communities whose role is to connect ocean science, ONC data, and Indigenous knowledge. By directly employing Indigenous youth in communities in which ONC operates monitoring equipment, ONC aims to encourage wider participation and interest in ocean science and exploration. Further, the Youth Science Ambassadors act as role models and mentors to other local youth by highlighting connections between Indigenous and local knowledge and current marine science efforts. Ocean Networks Canada, an initiative of the University of Victoria, develops, operates, and maintains cabled ocean observatory systems. These include technologies developed on the world-leading NEPTUNE and VENUS observatories as well as community observatories in the Arctic and coastal British Columbia. These observatories, large and small, enable communities, users, scientists, teachers, and students to monitor real-time and historical data from the local marine environment from anywhere on the globe. Youth Science Ambassadors are part of the Learning and Engagement team whose role includes engaging Indigenous communities and schools in ocean science through ONC's K-12 Ocean Sense education program. All of the data collected by ONC are freely available over the Internet for non-profit use, including disaster planning, community-based decision making, and education. The Youth Science Ambassadors support collaboration with Indigenous communities and schools by facilitating educational programming, encouraging participation in ocean data collection and analysis, and fostering interest in ocean science. In addition, the Youth Science Ambassadors support community collaboration in decision-making for instrument deployment locations and identify ways in which ONC can help to address any areas of concern raised by the community. This

  13. Biogeographic Characterization of Fish Communities within the Flower Garden Banks National Marine Sanctuary (2006 - 2007)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The overarching goal of this collaboration was to provide the Flower Garden Banks National Marine Sanctuary (FGBNMS) staff with information on biogeographic patterns...

  14. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris.

    Science.gov (United States)

    Oberbeckmann, Sonja; Osborn, A Mark; Duhaime, Melissa B

    2016-01-01

    Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5-6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae-all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the PET

  15. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris

    Science.gov (United States)

    Osborn, A. Mark

    2016-01-01

    Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate) (PET) drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5–6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae—all known to degrade complex carbon substrates) and diatoms (e.g. Coscinodiscophytina, Bacillariophytina). The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm) communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact with the

  16. Microbes on a Bottle: Substrate, Season and Geography Influence Community Composition of Microbes Colonizing Marine Plastic Debris.

    Directory of Open Access Journals (Sweden)

    Sonja Oberbeckmann

    Full Text Available Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial communities. This work aimed to characterize microbial biofilm communities colonizing single-use poly(ethylene terephthalate (PET drinking bottles, determine their plastic-specificity in contrast with seawater and glass-colonizing communities, and identify seasonal and geographical influences on the communities. A substrate recruitment experiment was established in which PET bottles were deployed for 5-6 weeks at three stations in the North Sea in three different seasons. The structure and composition of the PET-colonizing bacterial/archaeal and eukaryotic communities varied with season and station. Abundant PET-colonizing taxa belonged to the phylum Bacteroidetes (e.g. Flavobacteriaceae, Cryomorphaceae, Saprospiraceae-all known to degrade complex carbon substrates and diatoms (e.g. Coscinodiscophytina, Bacillariophytina. The PET-colonizing microbial communities differed significantly from free-living communities, but from particle-associated (>3 μm communities or those inhabiting glass substrates. These data suggest that microbial community assembly on plastics is driven by conventional marine biofilm processes, with the plastic surface serving as raft for attachment, rather than selecting for recruitment of plastic-specific microbial colonizers. A small proportion of taxa, notably, members of the Cryomorphaceae and Alcanivoraceae, were significantly discriminant of PET but not glass surfaces, conjuring the possibility that these groups may directly interact

  17. [Trends of microalgal biotechnology: a view from bibliometrics].

    Science.gov (United States)

    Yang, Xiaoqiu; Wu, Yinsong; Yan, Jinding; Song, Haigang; Fan, Jianhua; Li, Yuanguang

    2015-10-01

    Microalgae is a single-cell organism with the characteristics of high light energy utilization rate, fast growth rate, high-value bioactive components and high energy material content. Therefore, microalgae has broad application prospects in food, feed, bioenergy, carbon sequestration, wastewater treatment and other fields. In this article, the microalgae biotechnology development in recent years were fully consulted, through analysis from the literature and patent. The progress of microalgal biotechnology at home and abroad is compared and discussed. Furthermore, the project layout, important achievements and development bottlenecks of microalgae biotechnology in our country were also summarized. At last, future development directions of microalgae biotechnology were discussed.

  18. Multiple Drivers of Local (Non- Compliance in Community-Based Marine Resource Management: Case Studies from the South Pacific

    Directory of Open Access Journals (Sweden)

    Janne R. Rohe

    2017-05-01

    Full Text Available The outcomes of marine conservation and related management interventions depend to a large extent on people's compliance with these rule systems. In the South Pacific, community-based marine resource management (CBMRM has gained wide recognition as a strategy for the sustainable management of marine resources. In current practice, CBMRM initiatives often build upon customary forms of marine governance, integrating scientific advice and management principles in collaboration with external partners. However, diverse socio-economic developments as well as limited legal mandates can challenge these approaches. Compliance with and effective (legally-backed enforcement of local management strategies constitute a growing challenge for communities—often resulting in considerable impact on the success or failure of CBMRM. Marine management arrangements are highly dynamic over time, and similarly compliance with rule systems tends to change depending on context. Understanding the factors contributing to (non- compliance in a given setting is key to the design and function of adaptive management approaches. Yet, few empirical studies have looked in depth into the dynamics around local (non- compliance with local marine tenure rules under the transforming management arrangements. Using two case studies from Solomon Islands and Fiji, we investigate what drives local (non- compliance with CBMRM and what hinders or supports its effective enforcement. The case studies reveal that non-compliance is mainly driven by: (1 diminishing perceived legitimacy of local rules and rule-makers; (2 increased incentives to break rules due to market access and/ or lack of alternative income; and (3 relatively weak enforcement of local rules (i.e., low perceptions of risk from sanctions for rule-breaking. These drivers do not stand alone but can act together and add up to impair effective management. We further analyze how enforcement of CBMRM is challenged through a range of

  19. Microalgal biofactories: a promising approach towards sustainable omega-3 fatty acid production

    Directory of Open Access Journals (Sweden)

    Adarme-Vega T

    2012-07-01

    Full Text Available Abstract Omega-3 fatty acids eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA provide significant health benefits and this has led to an increased consumption as dietary supplements. Omega-3 fatty acids EPA and DHA are found in animals, transgenic plants, fungi and many microorganisms but are typically extracted from fatty fish, putting additional pressures on global fish stocks. As primary producers, many marine microalgae are rich in EPA (C20:5 and DHA (C22:6 and present a promising source of omega-3 fatty acids. Several heterotrophic microalgae have been used as biofactories for omega-3 fatty acids commercially, but a strong interest in autotrophic microalgae has emerged in recent years as microalgae are being developed as biofuel crops. This paper provides an overview of microalgal biotechnology and production platforms for the development of omega-3 fatty acids EPA and DHA. It refers to implications in current biotechnological uses of microalgae as aquaculture feed and future biofuel crops and explores potential applications of metabolic engineering and selective breeding to accumulate large amounts of omega-3 fatty acids in autotrophic microalgae.

  20. Modeling bubble dynamics and radical kinetics in ultrasound induced microalgal cell disruption.

    Science.gov (United States)

    Wang, Meng; Yuan, Wenqiao

    2016-01-01

    Microalgal cell disruption induced by acoustic cavitation was simulated through solving the bubble dynamics in an acoustical field and their radial kinetics (chemical kinetics of radical species) occurring in the bubble during its oscillation, as well as calculating the bubble wall pressure at the collapse point. Modeling results indicated that increasing ultrasonic intensity led to a substantial increase in the number of bubbles formed during acoustic cavitation, however, the pressure generated when the bubbles collapsed decreased. Therefore, cumulative collapse pressure (CCP) of bubbles was used to quantify acoustic disruption of a freshwater alga, Scenedesmus dimorphus, and a marine alga, Nannochloropsis oculata and compare with experimental results. The strong correlations between CCP and the intracellular lipid fluorescence density, chlorophyll-a fluorescence density, and cell particle/debris concentration were found, which suggests that the developed models could accurately predict acoustic cell disruption, and can be utilized in the scale up and optimization of the process. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Redox conditions and marine microbial community changes during the end-Ordovician mass extinction event

    Science.gov (United States)

    Smolarek, Justyna; Marynowski, Leszek; Trela, Wiesław; Kujawski, Piotr; Simoneit, Bernd R. T.

    2017-02-01

    The end-Ordovician (Hirnantian) crisis is the first globally distinct extinction during the Phanerozoic, but its causes are still not fully known. Here, we present an integrated geochemical and petrographic analysis to understand the sedimentary conditions taking place before, during and after the Late Ordovician ice age. New data from the Zbrza (Holy Cross Mountains) and Gołdap (Baltic Depression) boreholes shows that, like in other worldwide sections, the total organic carbon (TOC) content is elevated in the upper Katian and uppermost Hirnantian to Rhudannian black shales, but depleted (below 1%) during most of the Hirnantian. Euxinic conditions occurred in the photic zone in both TOC-rich intervals. This is based on the maleimide distribution, occurrence of aryl isoprenoids and isorenieratane, as well as a dominance of tiny pyrite framboids. Euxinic conditions were interrupted by the Hirnantian regression caused by glaciation. Sedimentation on the deep shelf changed to aerobic probably due to intense thermohaline circulation. Euxinia in the water column occurred directly during the time associated with the second pulse of the mass extinction with a termination of the end-Ordovician glaciation and sea level rise just at the Ordovician/Silurian (O/S) boundary. In contrast, we suggest based on inorganic proxies that bottom water conditions were generally oxic to dysoxic due to upwelling in the Rheic Ocean. The only episode of seafloor anoxia in the Zbrza basin was found at the O/S boundary, where all inorganic indicators showed elevated values typical for anoxia (U/Th > 1.25; V/Cr > 4.25; V/(V + Ni): 0.54-0.82 and Mo > 10-25 ppm). Significant differences in hopanes to steranes ratio and in C27-C29 sterane distribution between the Katian, Rhudannian and Hirnantian deposits indicate changes in marine microbial communities triggered by sharp climate change and Gondwana glaciation. The increase from biomarkers of cyanobacteria (2α-methylhopanes) after the O

  2. Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands.

    Directory of Open Access Journals (Sweden)

    Carmen Rojo

    Full Text Available The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abundance and composition of planktonic and benthic microalgae was determined. Variation partitioning analysis (as explained by spatial distance or environmental factors was applied to each seasonal dataset by means of partial redundancy analysis. Our results show that microalgal assemblages were structured by spatial and environmental factors depending on the hydrological period of the year. At the onset of hydroperiod and during flooding, neutral effects dominated community dynamics, but niche-based local effects resulted in more structured algal communities at the final periods of desiccating water bodies. Results suggest that climate-mediated effects on hydrology can influence the relative role of spatial and environmental factors on metacommunities of microalgae. Such variability needs to be accounted in order to describe accurately community dynamics in tropical coastal wetlands.

  3. Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands.

    Science.gov (United States)

    Rojo, Carmen; Mesquita-Joanes, Francesc; Monrós, Juan S; Armengol, Javier; Sasa, Mahmood; Bonilla, Fabián; Rueda, Ricardo; Benavent-Corai, José; Piculo, Rubén; Segura, M Matilde

    2016-01-01

    The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abundance and composition of planktonic and benthic microalgae was determined. Variation partitioning analysis (as explained by spatial distance or environmental factors) was applied to each seasonal dataset by means of partial redundancy analysis. Our results show that microalgal assemblages were structured by spatial and environmental factors depending on the hydrological period of the year. At the onset of hydroperiod and during flooding, neutral effects dominated community dynamics, but niche-based local effects resulted in more structured algal communities at the final periods of desiccating water bodies. Results suggest that climate-mediated effects on hydrology can influence the relative role of spatial and environmental factors on metacommunities of microalgae. Such variability needs to be accounted in order to describe accurately community dynamics in tropical coastal wetlands.

  4. Light requirements in microalgal photobioreactors. An overview of biophotonic aspects

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Ana P. [Universidade Catolica Portuguesa, Porto (Portugal). CBQF/Escola Superior de Biotecnologia; Silva, Susana O. [Universidade Catolica Portuguesa, Porto (Portugal). CBQF/Escola Superior de Biotecnologia; INESC Porto, Porto (Portugal); Baptista, Jose M. [INESC Porto, Porto (Portugal); Universidade da Madeira, Funchal (Portugal). Centro de Competencia de Ciencias Exactas e de Engenharia; Malcata, F. Xavier [ISMAI - Instituto Superior da Maia, Avioso S. Pedro (Portugal); Universidade Nova de Lisboa, Oeiras (Portugal). Inst. de Tecnologia Quimica e Biologica

    2011-03-15

    In order to enhance microalgal growth in photobioreactors (PBRs), light requirement is one of the most important parameters to be addressed; light should indeed be provided at the appropriate intensity, duration, and wavelength. Excessive intensity may lead to photo-oxidation and -inhibition, whereas low light levels will become growth-limiting. The constraint of light saturation may be overcome via either of two approaches: increasing photosynthetic efficiency by genetic engineering, aimed at changing the chlorophyll antenna size; or increasing flux tolerance, via tailoring the photonic spectrum, coupled with its intensity and temporal characteristics. These approaches will allow an increased control over the illumination features, leading to maximization of microalgal biomass and metabolite productivity. This minireview briefly introduces the nature of light, and describes its harvesting and transformation by microalgae, as well as its metabolic effects under excessively low or high supply. Optimization of the photosynthetic efficiency is discussed under the two approaches referred to above; the selection of light sources, coupled with recent improvements in light handling by PBRs, are chronologically reviewed and critically compared. (orig.)

  5. Thermochemical conversion of microalgal biomass into biofuels: a review.

    Science.gov (United States)

    Chen, Wei-Hsin; Lin, Bo-Jhih; Huang, Ming-Yueh; Chang, Jo-Shu

    2015-05-01

    Following first-generation and second-generation biofuels produced from food and non-food crops, respectively, algal biomass has become an important feedstock for the production of third-generation biofuels. Microalgal biomass is characterized by rapid growth and high carbon fixing efficiency when they grow. On account of potential of mass production and greenhouse gas uptake, microalgae are promising feedstocks for biofuels development. Thermochemical conversion is an effective process for biofuel production from biomass. The technology mainly includes torrefaction, liquefaction, pyrolysis, and gasification. Through these conversion technologies, solid, liquid, and gaseous biofuels are produced from microalgae for heat and power generation. The liquid bio-oils can further be upgraded for chemicals, while the synthesis gas can be synthesized into liquid fuels. This paper aims to provide a state-of-the-art review of the thermochemical conversion technologies of microalgal biomass into fuels. Detailed conversion processes and their outcome are also addressed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Microalgal biomass pretreatment for bioethanol production: a review

    Directory of Open Access Journals (Sweden)

    Jesús Velazquez-Lucio

    2018-03-01

    Full Text Available Biofuels derived from microalgae biomass have received a great deal of attention owing to their high potentials as sustainable alternatives to fossil fuels. Microalgae have a high capacity of CO2 fixation and depending on their growth conditions, they can accumulate different quantities of lipids, proteins, and carbohydrates. Microalgal biomass can, therefore, represent a rich source of fermentable sugars for third generation bioethanol production. The utilization of microalgal carbohydrates for bioethanol production follows three main stages: i pretreatment, ii saccharification, and iii fermentation. One of the most important stages is the pretreatment, which is carried out to increase the accessibility to intracellular sugars, and thus plays an important role in improving the overall efficiency of the bioethanol production process. Diverse types of pretreatments are currently used including chemical, thermal, mechanical, biological, and their combinations, which can promote cell disruption, facilitate extraction, and result in the modification the structure of carbohydrates as well as the production of fermentable sugars. In this review, the different pretreatments used on microalgae biomass for bioethanol production are presented and discussed. Moreover, the methods used for starch and total carbohydrates quantification in microalgae biomass are also briefly presented and compared.

  7. Metabolic engineering of microalgal based biofuel production: prospects and challenges

    Directory of Open Access Journals (Sweden)

    Chiranjib eBanerjee

    2016-03-01

    Full Text Available The current scenario in renewable energy is focused on development of alternate and sustainable energy sources, amongst which microalgae stands as one of the promising feedstock for biofuel production. It is well known that microalgae generate much larger amounts of biofuels in a shorter time than other sources based on plant seeds. However, the greatest challenge in a transition to algae-based biofuel production is the various other complications involved in microalgal cultivation, its harvesting, concentration, drying and lipid extraction. Several green microalgae accumulate lipids, especially triacylglycerols (TAGs, which are main precursors in the production of lipid. The various aspects on metabolic pathway analysis of an oleaginous microalgae i.e. Chlamydomonas reinhardtii have elucidated some novel metabolically important genes and this enhances the lipid production in this microalgae. Adding to it, various other aspects in metabolic engineering using OptFlux and effectual bioprocess design also gives an interactive snapshot of enhancing lipid production which ultimately improvises the oil yield. This article reviews the current status of microalgal based technologies for biofuel production, bioreactor process design, flux analysis and it also provides various strategies to increase lipids accumulation via metabolic engineering.

  8. Applications of Microalgal Biotechnology for Disease Control in Aquaculture

    Directory of Open Access Journals (Sweden)

    Patai Charoonnart

    2018-04-01

    Full Text Available Aquaculture industries, and in particular the farming of fish and crustaceans, are major contributors to the economy of many countries and an increasingly important component in global food supply. However, the severe impact of aquatic microbial diseases on production performance remains a challenge to these industries. This article considers the potential applications of microalgal technology in the control of such diseases. At the simplest level, microalgae offer health-promoting benefits as a nutritional supplement in feed meal because of their digestibility and high content of proteins, lipids and essential nutrients. Furthermore, some microalgal species possess natural anti-microbial compounds or contain biomolecules that can serve as immunostimulants. In addition, emerging genetic engineering technologies in microalgae offer the possibility of producing ‘functional feed additives’ in which novel and specific bioactives, such as fish growth hormones, anti-bacterials, subunit vaccines, and virus-targeted interfering RNAs, are components of the algal supplement. The evaluation of such technologies for farm applications is an important step in the future development of sustainable aquaculture.

  9. Adsorptive removal of cesium using bio fuel extraction microalgal waste

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Katsutoshi, E-mail: inoue@elechem.chem.saga-u.ac.jp [Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo 1, Saga 840-8502 (Japan); Gurung, Manju [Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo 1, Saga 840-8502 (Japan); Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John' s, NL, Canada A1B 3X5 (Canada); Adhikari, Birendra Babu; Alam, Shafiq [Faculty of Engineering and Applied Science, Memorial University of Newfoundland, St. John' s, NL, Canada A1B 3X5 (Canada); Kawakita, Hidetaka; Ohto, Keisuke [Department of Applied Chemistry, Faculty of Science and Engineering, Saga University, Honjo 1, Saga 840-8502 (Japan); Kurata, Minoru [Research Laboratories, DENSO CORPORATION, Minamiyama 500-1, Komenoki, Nisshin, Aichi 470-0111 (Japan); Atsumi, Kinya [New Business Promotion Dept., DENSO CORPORATION, Showa-cho 1-1, Kariya, Aichi 448-8661 (Japan)

    2014-04-01

    Highlights: • A novel biosorbent was prepared from the microalgal waste after biofuel extraction. • Higher selectivity and adsorption efficiency of the adsorbent for Cs{sup +} over Na{sup +} ions from aqueous solutions. • Potential candidate and eco-friendly alternative to the commercial resins such as zeolite. - Abstract: An adsorption gel was prepared from microalgal waste after extracting biodiesel oil by a simple chemical treatment of crosslinking using concentrated sulfuric acid. The adsorbent exhibited notably high selectivity and adsorption capacity towards Cs{sup +} over Na{sup +} from aqueous solutions, within the pH range of slightly acidic to neutral. The adsorption followed Langmuir isotherm and the maximum adsorption capacity of the gel for Cs{sup +} calculated from Langmuir model was found to be 1.36 mol kg{sup −1}. Trace concentration of Cs{sup +} ions present in aqueous streams was successfully separated from Na{sup +} ions using a column packed with the adsorbent at pH 6.5. The adsorption capacity of the gel towards Cs{sup +} in column operation was 0.13 mol kg{sup −1}. Although the adsorbed Cs{sup +} ions were easily eluted using 1 M hydrochloric acid solution, simple incineration is proposed as an alternative for the treatment of adsorbent loaded with radioactive Cs{sup +} ions due to the combustible characteristics of this adsorbent.

  10. Energy analysis and environmental impacts of microalgal biodiesel in China

    International Nuclear Information System (INIS)

    Liao Yanfen; Huang Zehao; Ma Xiaoqian

    2012-01-01

    The entire life cycle of biodiesel produced by microalgal biomasses was evaluated using the method of life cycle assessment (LCA) to identify and quantify the fossil energy requirements and environmental impact loading of the system. The life cycle considers microalgae cultivation, harvesting, drying, oil extraction, anaerobic digestion, oil transportation, esterification, biodiesel transportation and biodiesel combustion. The investigation results show that the fossil energy requirement for the biodiesel production is 0.74 MJ/MJ biodiesel, indicating that 1 MJ of biodiesel requires an input of 0.74 MJ of fossil energy. Accordingly, biodiesel production is feasible as an energy producing process. The environmental impact loading of microalgal biodiesel is 3.69 PET 2010 (Person Equivalents, Targeted, in 2010) and the GWP is 0.16 kg CO 2-eq /MJ biodiesel. The effects of photochemical ozone formation were greatest among all calculated categorization impacts. The fossil energy requirement and GWP in this operation were found to be particularly sensitive to oil content, drying rate and esterification rate. Overall, the results presented herein indicate that the cultivation of microalgae has the potential to produce an environmentally sustainable feedstock for the production of biodiesel. - Highlights: ► Do energy analysis and environmental impacts of algal biodiesel in China. ► GWP and energy consumption are sensitive to lipid content and drying rate. ► Fossil energy consumption for algal biodiesel is 0.74 MJ/MJ. ► Microalgae are an environmentally sustainable feedstock for biodiesel production.

  11. A comparison of community and trophic structure in five marine ecosystems based on energy budgets and system metrics

    Science.gov (United States)

    Gaichas, Sarah; Skaret, Georg; Falk-Petersen, Jannike; Link, Jason S.; Overholtz, William; Megrey, Bernard A.; Gjøsæter, Harald; Stockhausen, William T.; Dommasnes, Are; Friedland, Kevin D.; Aydin, Kerim

    2009-04-01

    Energy budget models for five marine ecosystems were compared to identify differences and similarities in trophic and community structure. We examined the Gulf of Maine and Georges Bank in the northwest Atlantic Ocean, the combined Norwegian/Barents Seas in the northeast Atlantic Ocean, and the eastern Bering Sea and the Gulf of Alaska in the northeast Pacific Ocean. Comparable energy budgets were constructed for each ecosystem by aggregating information for similar species groups into consistent functional groups. Several ecosystem indices (e.g., functional group production, consumption and biomass ratios, cumulative biomass, food web macrodescriptors, and network metrics) were compared for each ecosystem. The comparative approach clearly identified data gaps for each ecosystem, an important outcome of this work. Commonalities across the ecosystems included overall high primary production and energy flow at low trophic levels, high production and consumption by carnivorous zooplankton, and similar proportions of apex predator to lower trophic level biomass. Major differences included distinct biomass ratios of pelagic to demersal fish, ranging from highest in the combined Norwegian/Barents ecosystem to lowest in the Alaskan systems, and notable differences in primary production per unit area, highest in the Alaskan and Georges Bank/Gulf of Maine ecosystems, and lowest in the Norwegian ecosystems. While comparing a disparate group of organisms across a wide range of marine ecosystems is challenging, this work demonstrates that standardized metrics both elucidate properties common to marine ecosystems and identify key distinctions useful for fisheries management.

  12. Identification of Carbohydrate Metabolism Genes in the Metagenome of a Marine Biofilm Community Shown to Be Dominated by Gammaproteobacteria and Bacteroidetes

    Directory of Open Access Journals (Sweden)

    Jennifer L. Edwards

    2010-10-01

    Full Text Available Polysaccharides are an important source of organic carbon in the marine environment and degradation of the insoluble and globally abundant cellulose is a major component of the marine carbon cycle. Although a number of species of cultured bacteria are known to degrade crystalline cellulose, little is known of the polysaccharide hydrolases expressed by cellulose-degrading microbial communities, particularly in the marine environment. Next generation 454 Pyrosequencing was applied to analyze the microbial community that colonizes and degrades insoluble polysaccharides in situ in the Irish Sea. The bioinformatics tool MG-RAST was used to examine the randomly sampled data for taxonomic markers and functional genes, and showed that the community was dominated by members of the Gammaproteobacteria and Bacteroidetes. Furthermore, the identification of 211 gene sequences matched to a custom-made database comprising the members of nine glycoside hydrolase families revealed an extensive repertoire of functional genes predicted to be involved in cellulose utilization. This demonstrates that the use of an in situ cellulose baiting method yielded a marine microbial metagenome considerably enriched in functional genes involved in polysaccharide degradation. The research reported here is the first designed to specifically address the bacterial communities that colonize and degrade cellulose in the marine environment and to evaluate the glycoside hydrolase (cellulase and chitinase gene repertoire of that community, in the absence of the biases associated with PCR-based molecular techniques.

  13. Distribution and abundance of phytobenthic communities: Implications for connectivity and ecosystem functioning in a Black Sea Marine Protected Area

    Science.gov (United States)

    Berov, Dimitar; Todorova, Valentina; Dimitrov, Lubomir; Rinde, Eli; Karamfilov, Ventzislav

    2018-01-01

    The distribution and abundance of macroalgal communities in a Marine Protected Area (MPA) along the Bulgarian Black Sea coast were mapped and quantified, with particular focus on the previously unstudied P. crispa lower-infralittoral communities on Ostrea edulis biogenic reefs. Data from high resolution geophysical substrate mapping were combined with benthic community observations from georeferenced benthic photographic surveys and sampling. Multivariate analysis identified four distinct assemblages of lower-infralittoral macroalgal communities at depths between 10 and 17 m, dominated by Phyllophora crispa, Apoglossum ruscifoluim, Zanardinia typus and Gelidium spp. Maxent software analysis showed distinct preferences of the identified communities to areas with specific ranges of depth, inclination and curvature, with P. crispa more frequently occurring on vertical oyster biogenic reef structures. By combining production rates from literature, biomass measurements and the produced habitat maps, the highest proportion of primary production and DOC release was shown for the upper infralittoral Cystoseira barbata and Cystoseira bosphorica, followed by the production of the lower-infralittoral macroalgae. The observed distribution of P. crispa within the studied MPA was related to the network of Natura 2000 maritime MPAs along the Bulgarian Black Sea coast, which indicated that the connectivity of the populations of the species within the established network is insufficient within this cell of ecosystem functioning.

  14. Taxonomic and functional diversity of a coastal planktonic bacterial community in a river-influenced marine area.

    Science.gov (United States)

    Thiele, Stefan; Richter, Michael; Balestra, Cecilia; Glöckner, Frank Oliver; Casotti, Raffaella

    2017-04-01

    The Gulf of Naples is a dynamical area with intense exchanges between offshore oligotrophic and coastal eutrophic waters with frequent freshwater inputs. The Sarno River, one of the most polluted rivers in Europe, strongly contributes to the pollution of the area, discharging high amounts of heavy metals and organic wastes from heavily cultivated and industrial areas. This paper reports on the diversity and community structure of the marine residential Bacteria and Archaea of the Gulf of Naples in an area close to the river Sarno plume and investigates their small-scale taxonomic diversity and expression patterns as a proxy of potential metabolic activity using metagenomics and metatranscriptomics. Bacteria and Archaea were mainly represented by marine clades, with only minor contributors from freshwater ones. The community was dominated by Alpha- and Gammaproteobacteria, of which Rhodospirillales, Pelagibacteriales, and Oceanospirilalles were most represented. However, Alteromonadales and Rhodobacterales were the most active, despite their relative lower abundance, suggesting that they are important for overall ecosystem functioning and nutrient cycling. Nitrification and a reversed form of dissimilatory sulfate reduction were the major metabolic processes found in the metatrascriptomes and were mainly associated to Nitrosopumilales and Pelagibacter, respectively. No clear indication of transcripts related to stress induced by heavy metals or organic pollutants was found. In general, despite the high loads of pollutants discharged continuously by the Sarno River, the microbial community did not show marks of stress-induced changes neither structural nor functional, thus suggesting that this river has little or no effect on the planktonic bacterial community of the Gulf of Naples. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Fouling diatom community with reference to substratum variability in tropical marine environment

    Digital Repository Service at National Institute of Oceanography (India)

    Mitbavkar, S.; Desai, D.V.; Khandeparker, L.; Anil, A.C.; Wagh, A.B.

    form encountered. The paper deals with the qualitative and quantitative aspects of diatom colonization, their community structure, and correlation between the prevailing diatom population in the environment and that in the fouling community...

  16. Marine bacterioplankton community turnover within seasonally hypoxic waters of a subtropical sound

    DEFF Research Database (Denmark)

    Parsons, Rachel J.; Nelson, Craig E.; Carlson, Craig A.

    2015-01-01

    Understanding bacterioplankton community dynamics in coastal hypoxic environments is relevant to global biogeochemistry because coastal hypoxia is increasing worldwide. The temporal dynamics of bacterioplankton communities were analysed throughout the illuminated water column of Devil's Hole...

  17. Microfouling communities from pelagic and benthic marine plastic debris sampled across Mediterranean coastal waters

    Directory of Open Access Journals (Sweden)

    Mercedes Masó

    2016-09-01

    Full Text Available The present study used scanning electron microscopy to characterize the organisms colonizing marine plastic debris collected from pelagic and benthic habitats across Mediterranean coastal waters of Greece, Italy and Spain. A total of 42 fragments of plastic were collected during the COMSOM experimental cruise, 16 from the seafloor and 26 from surface waters. The results showed that diatoms were the most abundant organisms on both pelagic and benthic plastics. The diatom Ceratoneis closterium, frequently observed on surface plastics (73%, is a harmful microalgae associated with mucilage events in the Mediterranean. The abundance of marine plastic in coastal and oceanic waters may provide new habitats that offer an easy substrate for these invasive organisms. Furthermore, the colonization of these new environments might reduce the success of life strategies, or drive the organisms out of their essential habitat by dispersion and rafting phenomena. The results of the present work highlight the need to increase our knowledge of the consequences of colonization of plastics introduced into the marine environment, and the need to raise awareness of the potential impacts of debris accumulation on biodiversity of marine ecosystems.

  18. Marine communities : governing oil & gas activities and cruise tourism in the Arctic and the Caribbean

    NARCIS (Netherlands)

    Bets, Linde K.J.

    2017-01-01

    Oceans and seas are among the most ecologically vital and socio-economically important systems on the planet. Despite the acknowledged pristine nature of the marine environment, there is a growing interest in exploring the sea for human use such as offshore wind production, extraction of sand,

  19. Effects of the antibiotic ciprofloxacin on the bacterial community structure and degradation of pyrene in marine sediment

    International Nuclear Information System (INIS)

    Naeslund, Johan; Hedman, Jenny E.; Agestrand, Cecilia

    2008-01-01

    The ecological consequences of antibiotics in the aquatic environment have been an issue of concern over the past years due to the potential risk for negative effects on indigenous microorganisms. Microorganisms provide important ecosystem services, such as nutrient recycling, organic matter mineralization and degradation of pollutants. In this study, effects of exposure to the antibiotic ciprofloxacin on the bacterial diversity and pollutant degradation in natural marine sediments were studied using molecular methods (T-RFLP) in combination with radiorespirometry. In a microcosm experiment, sediment spiked with 14 C-labelled pyrene was exposed to five concentrations of ciprofloxacin (0, 20, 200, 1000 and 2000 μg L -1 ) in a single dose to the overlying water. The production of 14 CO 2 (i.e. complete mineralization of pyrene) was measured during 11 weeks. Sediment samples for bacterial community structure analysis were taken after 7 weeks. Results showed a significant dose-dependent inhibition of pyrene mineralization measured as the total 14 CO 2 production. The nominal EC 50 was calculated to 560 μg L -1 , corresponding to 0.4 μg/kg d.w. sediment. The lowest effect concentration on the bacterial community structure was 200 μg L -1 , which corresponds to 0.1 μg/kg d.w. sediment. Our results show that antibiotic pollution can be a potential threat to both bacterial diversity and an essential ecosystem service they perform in marine sediment

  20. Succession and physiological health of freshwater microalgal fouling in a Tasmanian hydropower canal.

    Science.gov (United States)

    Perkins, Kathryn J; Andrewartha, Jessica M; McMinn, Andrew; Cook, Suellen S; Hallegraeff, Gustaaf M

    2010-08-01

    Freshwater microalgal biofouling in hydropower canals in Tarraleah, Tasmania, is dominated by a single diatom species, Gomphonema tarraleahae. The microfouling community is under investigation with the aim of reducing its impact on electricity generation. Species succession was investigated using removable glass slides. Fouled slides were examined microscopically and for chlorophyll a biomass. Chl a biomass increased steeply after 8 weeks (0.09-0.87 mg m(-2)), but increased much earlier on slides surrounded by a biofouled inoculum. Succession began with low profile diatoms such as Tabellaria flocculosa, progressing to stalked diatoms such as Gomphonema spp. and Cymbella aspera. Few chlorophytes and no filamentous algae were present. Pulse amplitude modulated fluorometry was used to measure the physiological health of fouling on the canal wall. Maximum quantum yield (F(v)/F(m)) measurements were consistently <0.18, indicating that the fouling mat consisted of dead or dying algae. The succession and physiological health of cells in the fouling community has broad implications for mitigation techniques used.

  1. B-Vitamin Competition: Intracellular and Dissolved B-Vitamins Provide Insight into Marine Microbial Community Dynamics

    Science.gov (United States)

    Suffridge, C.; Gomez-Consarnau, L.; Qu, P.; Tenenbaum, N.; Fu, F.; Hutchins, D. A.; Sanudo-Wilhelmy, S. A.

    2016-02-01

    The availability of B-vitamins has the ability to directly affect the dynamics of the marine microbial community. Here we show, for the first time, the connection between dissolved and intracellular B-vitamins in a marine environmental community. Two incubation experiments were conducted at a long-term study site (SPOT) in the San Pedro Basin off the coast of Los Angeles, CA. Experiments were conducted in oligotrophic, preupwelling conditions. Due to the 2015 El Niño event, the seasonal upwelling at SPOT did not occur, creating unusually nutrient depleted conditions. Vitamins B1, B7, and B12 were added in addition to macronutrients at concentrations similar to typical SPOT upwelling conditions. Intracellular and dissolved B-vitamin analyses were conducted to determine shifts in cellular B-vitamin requirements as a function of growth rate. We observed a significant bacterioplankton and phytoplankton growth responses with the addition of B-vitamins in a manner that appears to match the enzymatic requirements for these compounds (e.g. B1>B7>B12). Intracellular B-vitamin analysis of T0 samples support this observation, as all four forms of B12 were not detectable within cells, yet multiple forms of B1 and B7 were detected at or near levels previously reported. Treatments with B12 and macronutrients were observed to have the greatest growth rates. This finding, in addition to the apparent lack of intracellular B12 in the initial community, appears to indicate that the initial microbial community was limited by B12. The addition of each vitamin caused a distinct shift in the blooming microbial community. Our results demonstrate that B-vitamins strongly influence not only the growth rate, but also the species composition and species succession of the microbial community as a whole. Large-scale changes to upwelling regimes are predicted in the future ocean; our results indicate that B-vitamins will have a substantial role in controlling microbial community dynamics under

  2. Third-generation biofuels: current and future research on microalgal lipid biotechnology

    Directory of Open Access Journals (Sweden)

    Li-Beisson Yonghua

    2013-11-01

    Full Text Available One pressing issue faced by modern societies is to develop renewable energy for transportation. Microalgal biomass offers an attractive solution due to its high (annual surface biomass productivity, efficient conversion of solar energy into chemical energy and the ability to grow on non-agricultural land. Despite these considerable advantages, microalgal biofuels are not yet commercially sustainable. Major challenges lie in improving both cultivation technologies and microalgal strains. A microalgal crop species is yet to emerge. In this review, we focus on researches aiming at understanding and harnessing lipid metabolism in microalgae in view of producing lipid-based biofuels such as biodiesel. Current biotechnological challenges and key progresses made in the development of algal models, genetic tools and lipid metabolic engineering strategies are reviewed. Possible future research directions to increase oil yields in microalgae are also highlighted.

  3. Resource Assessment for Microalgal/Emergent Aquatic Biomass Systems in the Arid Southwest: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Vigon, B. W.; Arthur, M. F.; Taft, L. G.; Wagner, C. K.; Lipinsky, E. S.; Litchfield, J. H.; McCandlish, C. D.; Clark, R.

    1982-12-23

    This research project has been designed to facilitate the eventual selection of biomass production systems using aquatic species (microalgal and emergent aquatic plant species (MEAP) which effectively exploit the potentially available resources of the Southwest.

  4. Size structure of marine soft-bottom macrobenthic communities across natural habitat gradients: implications for productivity and ecosystem function.

    Directory of Open Access Journals (Sweden)

    Tara A Macdonald

    Full Text Available Size distributions of biotic assemblages are important modifiers of productivity and function in marine sediments. We investigated the distribution of proportional organic biomass among logarithmic size classes (2(-6J to 2(16J in the soft-bottom macrofaunal communities of the Strait of Georgia, Salish Sea on the west coast of Canada. The study examines how size structure is influenced by 3 fundamental habitat descriptors: depth, sediment percent fines, and organic flux (modified by quality. These habitat variables are uncorrelated in this hydrographically diverse area, thus we examine their effects in combination and separately. Cluster analyses and cumulative biomass size spectra reveal clear and significant responses to each separate habitat variable. When combined, habitat factors result in three distinct assemblages: (1 communities with a high proportion of biomass in small organisms, typical of shallow areas (3 g C/m(2/yr/δ(15N from the Fraser River; and (3 communities with biomass dominated by moderately large organisms, but lacking the smallest and largest size classes, typical of deep, fine sediments experiencing low modified organic flux (<3.0 gC/m(2/yr/δ(15N. The remaining assemblages had intermediate habitat types and size structures. Sediment percent fines and flux appear to elicit threshold responses in size structure, whereas depth has the most linear influence on community size structure. The ecological implications of size structure in the Strait of Georgia relative to environmental conditions, secondary production and sediment bioturbation are discussed.

  5. The Impacts of Human Visitation on Mussel Bed Communities Along the California Coast: Are Regulatory Marine Reserves Effective in Protecting These Communities?

    Science.gov (United States)

    Smith, Jayson R.; Fong, Peggy; Ambrose, Richard F.

    2008-04-01

    Rocky intertidal habitats frequently are used by humans for recreational, educational, and subsistence-harvesting purposes, with intertidal populations damaged by visitation activities such as extraction, trampling, and handling. California Marine Managed Areas, particularly regulatory marine reserves (MRs), were established to provide legal protection and enhancement of coastal resources and include prohibitions on harvesting intertidal populations. However, the effectiveness of MRs is unclear as enforcement of no-take laws is weak and no regulations protect intertidal species from other detrimental visitor impacts such as trampling. The goal of this study was two-fold: (1) to determine impacts from human visitation on California mussel populations ( Mytilus californianus) and mussel bed community diversity; and (2) to investigate the effectiveness of regulatory MRs in reducing visitor impacts on these populations. Surveys of mussel populations and bed-associated diversity were compared: (1) at sites subjected to either high or low levels of human use, and (2) at sites either unprotected or with regulatory protection banning collecting. At sites subjected to higher levels of human visitation, mussel populations were significantly lower than low-use sites. Comparisons of mussel populations inside and outside of regulatory MRs revealed no consistent pattern suggesting that California no-take regulatory reserves may have limited effectiveness in protecting mussel communities. In areas where many people visit intertidal habitats for purposes other than collecting, many organisms will be affected by trampling, turning of rocks, and handling. In these cases, effective protection of rocky intertidal communities requires an approach that goes beyond the singular focus on collecting to reduce the full suite of impacts.

  6. Ocean acidification of a coastal Antarctic marine microbial community reveals a critical threshold for CO2 tolerance in phytoplankton productivity

    Science.gov (United States)

    Deppeler, Stacy; Petrou, Katherina; Schulz, Kai G.; Westwood, Karen; Pearce, Imojen; McKinlay, John; Davidson, Andrew

    2018-01-01

    High-latitude oceans are anticipated to be some of the first regions affected by ocean acidification. Despite this, the effect of ocean acidification on natural communities of Antarctic marine microbes is still not well understood. In this study we exposed an early spring, coastal marine microbial community in Prydz Bay to CO2 levels ranging from ambient (343 µatm) to 1641 µatm in six 650 L minicosms. Productivity assays were performed to identify whether a CO2 threshold existed that led to a change in primary productivity, bacterial productivity, and the accumulation of chlorophyll a (Chl a) and particulate organic matter (POM) in the minicosms. In addition, photophysiological measurements were performed to identify possible mechanisms driving changes in the phytoplankton community. A critical threshold for tolerance to ocean acidification was identified in the phytoplankton community between 953 and 1140 µatm. CO2 levels ≥ 1140 µatm negatively affected photosynthetic performance and Chl a-normalised primary productivity (csGPP14C), causing significant reductions in gross primary production (GPP14C), Chl a accumulation, nutrient uptake, and POM production. However, there was no effect of CO2 on C : N ratios. Over time, the phytoplankton community acclimated to high CO2 conditions, showing a down-regulation of carbon concentrating mechanisms (CCMs) and likely adjusting other intracellular processes. Bacterial abundance initially increased in CO2 treatments ≥ 953 µatm (days 3-5), yet gross bacterial production (GBP14C) remained unchanged and cell-specific bacterial productivity (csBP14C) was reduced. Towards the end of the experiment, GBP14C and csBP14C markedly increased across all treatments regardless of CO2 availability. This coincided with increased organic matter availability (POC and PON) combined with improved efficiency of carbon uptake. Changes in phytoplankton community production could have negative effects on the Antarctic food web and the

  7. Ocean acidification of a coastal Antarctic marine microbial community reveals a critical threshold for CO2 tolerance in phytoplankton productivity

    Directory of Open Access Journals (Sweden)

    S. Deppeler

    2018-01-01

    Full Text Available High-latitude oceans are anticipated to be some of the first regions affected by ocean acidification. Despite this, the effect of ocean acidification on natural communities of Antarctic marine microbes is still not well understood. In this study we exposed an early spring, coastal marine microbial community in Prydz Bay to CO2 levels ranging from ambient (343 µatm to 1641 µatm in six 650 L minicosms. Productivity assays were performed to identify whether a CO2 threshold existed that led to a change in primary productivity, bacterial productivity, and the accumulation of chlorophyll a (Chl a and particulate organic matter (POM in the minicosms. In addition, photophysiological measurements were performed to identify possible mechanisms driving changes in the phytoplankton community. A critical threshold for tolerance to ocean acidification was identified in the phytoplankton community between 953 and 1140 µatm. CO2 levels  ≥ 1140 µatm negatively affected photosynthetic performance and Chl a-normalised primary productivity (csGPP14C, causing significant reductions in gross primary production (GPP14C, Chl a accumulation, nutrient uptake, and POM production. However, there was no effect of CO2 on C : N ratios. Over time, the phytoplankton community acclimated to high CO2 conditions, showing a down-regulation of carbon concentrating mechanisms (CCMs and likely adjusting other intracellular processes. Bacterial abundance initially increased in CO2 treatments  ≥ 953 µatm (days 3–5, yet gross bacterial production (GBP14C remained unchanged and cell-specific bacterial productivity (csBP14C was reduced. Towards the end of the experiment, GBP14C and csBP14C markedly increased across all treatments regardless of CO2 availability. This coincided with increased organic matter availability (POC and PON combined with improved efficiency of carbon uptake. Changes in phytoplankton community production could have negative

  8. Kinetics of inorganic carbon utilization by microalgal biofilm in a flat plate photoreactor

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y.H.; Leu, J.Y.; Lan, C.R.; Lin, P.H.P.; Chang, F.L. [Development Center for Biotechnology, Taipei (Taiwan). Dept. for Environmental Program

    2003-11-01

    A kinetic model was developed to describe inorganic carbon utilization by microalgae biofilm in a flat plate photoreactor. The model incorporates the fundamental mechanisms of diffusive mass transport and biological reaction of inorganic carbon by microalgal biofilm. An advanced numerical technique, the orthogonal collocation method and Gear's method, was employed to solve this kinetic model. The model solutions included the concentration profiles of inorganic carbon in the microalgal biofilm, the growths of suspended microalgae and microalgal biofilm, the effluent concentrations of inorganic carbon, and the flux of inorganic carbon from bulk liquid into biofilm. The batch kinetic test was independently conducted to determine biokinetic parameters used in the microalgal biofilm model simulation while initial thickness of microalgal biofilm were assumed. A laboratory-scale flat plate photoreactor with a high recycle flow rate was set up and conducted to verify the model. The volume of photoreactor is 60 l which yields a hydraulic retention time of 1.67 days. The model-generated inorganic carbon and the suspended microalgae concentration curves agreed well with those obtained in the laboratory-scale test. The fixation efficiencies of HCO{sub 3}{sup -} and CO{sub 2} are 98.5% and 90% at a steady-state condition, respectively. The concentration of suspended microalgal cell reached up to 12 mg/l at a maximum growth rate while the thickness of microalgal biofilm was estimated to be 104 pm at a steady-state condition. The approaches of experiments and model simulation presented in this study could be employed for the design of a flat plate photoreactor to treat CO{sub 2} by microalgal biofilm in a fossil-fuel power plant.

  9. An experimental investigation of microalgal dewatering efficiency of belt filter system

    Directory of Open Access Journals (Sweden)

    Anjali Sandip

    2015-11-01

    Full Text Available The objective of this study was to investigate the microalgal dewatering efficiency of a belt filter system for feed concentrations below 10 g dry wt./L. A prototype belt filtration system designed for 50 g dry wt./L microalgal feed concentration was used for this investigation. The highest concentration of microalgal suspension available for testing on the prototype belt filtration system was 6 g dry wt./L obtained from biomass settling tanks at the Lawrence, Kansas domestic wastewater treatment plant. For preparation of feed suspension with concentrations below 10 g dry wt./L, microalgal cultivation was followed by flocculation. A mixed laboratory culture of freshwater species dominated by three eukaryotic green microalgae (Chlorella vulgaris, Scenedesmus sp., and Kirchneriella sp. was cultivated in wastewater effluent. This was followed by flocculation which resulted in a microalgal feed suspension concentration of 4 g dry wt./L. Belt dewatering tests were conducted on microalgal suspensions with feed concentrations of 4 g dry wt./L and 6 g dry wt./L. The maximum microalgal recovery with the belt dewatering system was 46% from the 4 g dry wt./L, and 84% from the 6 g dry wt./L suspensions respectively. The results of this study indicate that microalgal suspension concentrations as low as 6 g dry wt./L can be recovered with a belt filter system improving the overall dewatering efficiency of the system.

  10. Shallow water marine sediment bacterial community shifts along a natural CO2 gradient in the Mediterranean Sea off Vulcano, Italy.

    Science.gov (United States)

    Kerfahi, Dorsaf; Hall-Spencer, Jason M; Tripathi, Binu M; Milazzo, Marco; Lee, Junghoon; Adams, Jonathan M

    2014-05-01

    The effects of increasing atmospheric CO(2) on ocean ecosystems are a major environmental concern, as rapid shoaling of the carbonate saturation horizon is exposing vast areas of marine sediments to corrosive waters worldwide. Natural CO(2) gradients off Vulcano, Italy, have revealed profound ecosystem changes along rocky shore habitats as carbonate saturation levels decrease, but no investigations have yet been made of the sedimentary habitat. Here, we sampled the upper 2 cm of volcanic sand in three zones, ambient (median pCO(2) 419 μatm, minimum Ω(arag) 3.77), moderately CO(2)-enriched (median pCO(2) 592 μatm, minimum Ω(arag) 2.96), and highly CO(2)-enriched (median pCO(2) 1611 μatm, minimum Ω(arag) 0.35). We tested the hypothesis that increasing levels of seawater pCO(2) would cause significant shifts in sediment bacterial community composition, as shown recently in epilithic biofilms at the study site. In this study, 454 pyrosequencing of the V1 to V3 region of the 16S rRNA gene revealed a shift in community composition with increasing pCO(2). The relative abundances of most of the dominant genera were unaffected by the pCO(2) gradient, although there were significant differences for some 5 % of the genera present (viz. Georgenia, Lutibacter, Photobacterium, Acinetobacter, and Paenibacillus), and Shannon Diversity was greatest in sediments subject to long-term acidification (>100 years). Overall, this supports the view that globally increased ocean pCO(2) will be associated with changes in sediment bacterial community composition but that most of these organisms are resilient. However, further work is required to assess whether these results apply to other types of coastal sediments and whether the changes in relative abundance of bacterial taxa that we observed can significantly alter the biogeochemical functions of marine sediments.

  11. Effects of different levels of UV-B radiation on marine epilithic communities: a short-term microcosm study

    Directory of Open Access Journals (Sweden)

    R. A. Danilov

    2000-12-01

    Full Text Available Epilithic communities from brackish coastal water of the east coast of Sweden were studied in order to reveal their responses to different levels of UV-B radiation. The experiment was conducted for seven days in an indoor microcosm system. The epilithic communities were exposed daily to different doses of UV-B radiation: 1, 3, 5 and 7 hours, respectively. The intensity of the UV-B radiation used was similar to that in natural environments. After seven days clear shifts both in species composition and community structure were observed. All species of diatoms showed negative correlation with enhanced levels of UV-B. On the other hand, abundance of cyanobacteria was positively correlated with enhanced levels of UV-B (Calothrix aeruginea, R=0.49;Oscillatoria amphibia, R=0.93; Pseudanabaena mucicola, R=0.26. Communities dominated by diatoms and green algae at the initial stage of the experiment did show a drastic decrease in diatom abundance under UV-B stress and finally became dominated by cyanobacteria. Among green algae the abundance of Cladophora sericea correlated positively (R=0.33 with enhanced exposure to UV-B, while Monoraphidium-species exhibited negative correlation to UV-B. Otherwise, no significant correlation between other green algae species identified and UV-B stress could be detected. We conclude that UV-B radiation, even at lower levels, is capable to induce severe changes to marine epilithic communities. The trends revealed in the present study predict a shift from communities dominated by diatoms and green algae to those dominated by cyanobacteria.

  12. Shifting elasmobranch community assemblage at Cocos Island--an isolated marine protected area.

    Science.gov (United States)

    White, Easton R; Myers, Mark C; Flemming, Joanna Mills; Baum, Julia K

    2015-08-01

    Fishing pressure has increased the extinction risk of many elasmobranch (shark and ray) species. Although many countries have established no-take marine reserves, a paucity of monitoring data means it is still unclear if reserves are effectively protecting these species. We examined data collected by a small group of divers over the past 21 years at one of the world's oldest marine protected areas (MPAs), Cocos Island National Park, Costa Rica. We used mixed effects models to determine trends in relative abundance, or probability of occurrence, of 12 monitored elasmobranch species while accounting for variation among observers and from abiotic factors. Eight of 12 species declined significantly over the past 2 decades. We documented decreases in relative abundance for 6 species, including the iconic scalloped hammerhead shark (Sphyrna lewini) (-45%), whitetip reef shark (Triaenodon obesus) (-77%), mobula ray (Mobula spp.) (-78%), and manta ray (Manta birostris) (-89%), and decreases in the probability of occurrence for 2 other species. Several of these species have small home ranges and should be better protected by an MPA, which underscores the notion that declines of marine megafauna will continue unabated in MPAs unless there is adequate enforcement effort to control fishing. In addition, probability of occurrence at Cocos Island of tiger (Galeocerdo cuvier), Galapagos (Carcharhinus galapagensis), blacktip (Carcharhinus limbatus), and whale (Rhincodon typus) sharks increased significantly. The effectiveness of MPAs cannot be evaluated by examining single species because population responses can vary depending on life history traits and vulnerability to fishing pressure. © 2015 Society for Conservation Biology.

  13. Diversity and biological activities of the bacterial community associated with the marine sponge Phorbas tenacior (Porifera, Demospongiae).

    Science.gov (United States)

    Dupont, S; Carré-Mlouka, A; Descarrega, F; Ereskovsky, A; Longeon, A; Mouray, E; Florent, I; Bourguet-Kondracki, M L

    2014-01-01

    The diversity of the cultivable microbiota of the marine sponge Phorbas tenacior frequently found in the Mediterranean Sea was investigated, and its potential as a source of antimicrobial, antioxidant and antiplasmodial compounds was evaluated. The cultivable bacterial community was studied by isolation, cultivation and 16S rRNA gene sequencing. Twenty-three bacterial strains were isolated and identified in the Proteobacteria (α or γ classes) and Actinobacteria phyla. Furthermore, three different bacterial morphotypes localized extracellularly within the sponge tissues were revealed by microscopic observations. Bacterial strains were assigned to seven different genera, namely Vibrio, Photobacterium, Shewanella, Pseudomonas, Ruegeria, Pseudovibrio and Citricoccus. The strains affiliated to the same genus were differentiated according to their genetic dissimilarities using random amplified polymorphic DNA (RAPD) analyses. Eleven bacterial strains were selected for evaluation of their bioactivities. Three isolates Pseudovibrio P1Ma4, Vibrio P1MaNal1 and Citricoccus P1S7 revealed antimicrobial activity; Citricoccus P1S7 and Vibrio P1MaNal1 isolates also exhibited antiplasmodial activity, while two Vibrio isolates P1Ma8 and P1Ma5 displayed antioxidant activity. These data confirmed the importance of Proteobacteria and Actinobacteria associated with marine sponges as a reservoir of bioactive compounds. This study presents the first report on the diversity of the cultivable bacteria associated with the marine sponge Phorbas tenacior, frequently found in the Mediterranean Sea. Evaluation of the antiplasmodial, antimicrobial and antioxidant activities of the isolates has been investigated and allowed to select bacterial strains, confirming the importance of Proteobacteria and Actinobacteria as sources of bioactive compounds. © 2013 The Society for Applied Microbiology.

  14. ZOOPLANKTON COMMUNITY STRUCTURE OF THE SEA SURFACE MICROLAYER NEAR NUCLEAR POWER PLANTS AND MARINE FISH CULTURE ZONES IN DAYA BAY

    Institute of Scientific and Technical Information of China (English)

    杨宇峰; 王肇鼎; 潘明祥; 焦念志

    2002-01-01

    The authors' surveys in May-June 1999 (two cruises) at six sampling stations near nuclear power plants (NPP) and marine fish culture zones in Daya Bay, Guangdong, revealed species composition, densities and body-size of thesea surface microlayer (SM) zooplankton (>35 μm). Results showed that protozoans and copepod nauplii were the predominant components, accounting for 65.40% to95.56% of total zooplankton in abundance. The size-frequency distributions showed that the frequency of micro-zooplankton (0.02-0.2 mm) reached 0.8235. The SM zooplankton community structure revealed in the present study was quite different from that revealed by investigations in the 1980s in Daya Bay. Difference of sampling method has important influence on the obtained zooplankton community structure. SM zooplankton consisted of micro- and mesozooplankton (0.2-2.0 mm), with micro-zooplankton being predominant. Some possible cause-effect relations between the zooplankton community structure and mariculture, nuclear power plants cooling systems and sampling method are discussed.``

  15. Anaerobic Methane-Oxidizing Microbial Community in a Coastal Marine Sediment: Anaerobic Methanotrophy Dominated by ANME-3.

    Science.gov (United States)

    Bhattarai, Susma; Cassarini, Chiara; Gonzalez-Gil, Graciela; Egger, Matthias; Slomp, Caroline P; Zhang, Yu; Esposito, Giovanni; Lens, Piet N L

    2017-10-01

    The microbial community inhabiting the shallow sulfate-methane transition zone in coastal sediments from marine Lake Grevelingen (The Netherlands) was characterized, and the ability of the microorganisms to carry out anaerobic oxidation of methane coupled to sulfate reduction was assessed in activity tests. In vitro activity tests of the sediment with methane and sulfate demonstrated sulfide production coupled to the simultaneous consumption of sulfate and methane at approximately equimolar ratios over a period of 150 days. The maximum sulfate reduction rate was 5 μmol sulfate per gram dry weight per day during the incubation period. Diverse archaeal and bacterial clades were retrieved from the sediment with the majority of them clustered with Euryarchaeota, Thaumarcheota, Bacteroidetes, and Proteobacteria. The 16S rRNA gene sequence analysis showed that the sediment from marine Lake Grevelingen contained anaerobic methanotrophic Archaea (ANME) and methanogens as archaeal clades with a role in the methane cycling. ANME at the studied site mainly belong to the ANME-3 clade. This study provides one of the few reports for the presence of ANME-3 in a shallow coastal sediment. Sulfate-reducing bacteria from Desulfobulbus clades were found among the sulfate reducers, however, with very low relative abundance. Desulfobulbus has previously been commonly found associated with ANME, whereas in our study, ANME-3 and Desulfobulbus were not observed simultaneously in clusters, suggesting the possibility of independent AOM by ANME-3.

  16. A novel approach to the assess biotic oxygen consumption in marine sediment communities

    Science.gov (United States)

    Baranov, Victor; Queiros, Ana; Widdicombe, Stephen; Stephens, Nick; Lessin, Gennadi; Krause, Stefan; Lewandowski, Joerg

    2016-04-01

    Bioturbation , the mixing of the sediment matrix by burrowing animals impacts sediment metabolism, including respiration through redistribution of particulate organics, changes in bacterial biota diversity and acitivity, as well as via burrowing fauna's own metabolism. Bioturbation, reflecting faunal activity, is also a proxy for the general sedimentary ecosystem health, and can be impacted by many of emerging marine environmental issues such as ocean acidification, warming and the occurrence of heat waves. Sedimentary oxygen consumption is often taken as a proxy for the activity of bioturbating fauna, but determining baselines can be difficult because of the confounding effects of other fauna and microbes present in sediments, as well as irnorganic processes that consume oxygen. Limitations therefore exist in current methodologies, and numerous confounding factors are hampering progress in this area. Here, we present novel method for the assessment of sediment respiration which is expected to be affected only by the biogenic oxygen consumption (namely aerobic respiration). As long as tracer reduction "immune" to inorganic oxygen consumption, so that measurements using this method can be used, alongside traditional methods, to decouple biological respiration from inorganic oxygen consumption reactions. The tracer is easily detectable, non-toxic and can be applied in systems with constant oxygen supply. The latter allow for incubation without the need to to work with unsealed experimental units, bringing procedural advantage over traditional methods. Consequently assessed bioturbating fauna is not exposed to hypoxia and additional stress. Here, we had applied system for the first time to investigate impacts of a common North-Atlantic bioturbator, the brittle star Amphiura filiformis, - on respiration of marine sediments. Two series of experiments were conducted with animals and sediment collected from Cawsand Bay, Plymouth, UK Preliminary results show that tracer

  17. Biological Soil Crusts of Arctic Svalbard—Water Availability as Potential Controlling Factor for Microalgal Biodiversity

    Directory of Open Access Journals (Sweden)

    Nadine Borchhardt

    2017-08-01

    Full Text Available In the present study the biodiversity of biological soil crusts (BSCs formed by phototrophic organisms were investigated on Arctic Svalbard (Norway. These communities exert several important ecological functions and constitute a significant part of vegetation at high latitudes. Non-diatom eukaryotic microalgal species of BSCs from 20 sampling stations around Ny-Ålesund and Longyearbyen were identified by morphology using light microscopy, and the results revealed a high species richness with 102 species in total. 67 taxa belonged to Chlorophyta (31 Chlorophyceae and 36 Trebouxiophyceae, 13 species were Streptophyta (11 Klebsormidiophyceae and two Zygnematophyceae and 22 species were Ochrophyta (two Eustigmatophyceae and 20 Xanthophyceae. Surprisingly, Klebsormidium strains belonging to clade G (Streptophyta, which were so far described from Southern Africa, could be determined at 5 sampling stations. Furthermore, comparative analyses of Arctic and Antarctic BSCs were undertaken to outline differences in species composition. In addition, a pedological analysis of BSC samples included C, N, S, TP (total phosphorus, and pH measurements to investigate the influence of soil properties on species composition. No significant correlation with these chemical soil parameters was confirmed but the results indicated that pH might affect the BSCs. In addition, a statistically significant influence of precipitation on species composition was determined. Consequently, water availability was identified as one key driver for BSC biodiversity in Arctic regions.

  18. Biological Soil Crusts of Arctic Svalbard-Water Availability as Potential Controlling Factor for Microalgal Biodiversity.

    Science.gov (United States)

    Borchhardt, Nadine; Baum, Christel; Mikhailyuk, Tatiana; Karsten, Ulf

    2017-01-01

    In the present study the biodiversity of biological soil crusts (BSCs) formed by phototrophic organisms were investigated on Arctic Svalbard (Norway). These communities exert several important ecological functions and constitute a significant part of vegetation at high latitudes. Non-diatom eukaryotic microalgal species of BSCs from 20 sampling stations around Ny-Ålesund and Longyearbyen were identified by morphology using light microscopy, and the results revealed a high species richness with 102 species in total. 67 taxa belonged to Chlorophyta (31 Chlorophyceae and 36 Trebouxiophyceae), 13 species were Streptophyta (11 Klebsormidiophyceae and two Zygnematophyceae) and 22 species were Ochrophyta (two Eustigmatophyceae and 20 Xanthophyceae). Surprisingly, Klebsormidium strains belonging to clade G (Streptophyta), which were so far described from Southern Africa, could be determined at 5 sampling stations. Furthermore, comparative analyses of Arctic and Antarctic BSCs were undertaken to outline differences in species composition. In addition, a pedological analysis of BSC samples included C, N, S, TP (total phosphorus), and pH measurements to investigate the influence of soil properties on species composition. No significant correlation with these chemical soil parameters was confirmed but the results indicated that pH might affect the BSCs. In addition, a statistically significant influence of precipitation on species composition was determined. Consequently, water availability was identified as one key driver for BSC biodiversity in Arctic regions.

  19. Microalgal composition and primary production in Arctic sea ice: a seasonal study from Kobbeijord (Kangerluarsunnguaq), West Greenland

    DEFF Research Database (Denmark)

    Mikkelsen, Ditte Marie; Rysgaard, Søren; Glud, Ronnie N.

    2008-01-01

    We investigated the microalgal community in sea ice and in the water column of Kobbefjord, west Greenland, through an entire sea ice season, Temporal variation in physical (photosynthetically active radiation [PAR), temperature, brine volume) and chemical (salinity, nutrient concentration......) properties confirmed that sea ice is a very dynamic habitat. Nevertheless, a viable sea ice algal comuunity was present throughout the year, with a species succession from flagellate dominance (dinoflagellates and cryptophytes) in December to February, followed by Chaetoceros simplex (a centric diatom...... (maxima of 1.8 and 2.6 mu g chl](-1) in March and May, respectively). Primary production mirrored biomass dynamic, which had 2 seasonal peaks of ca. 21 and 15 mg Cm-2 d(-1). Integrated primary production over 7 mo was 0.8 g Cm-2 in sea ice and 94.4 g C m(-2) in the water column, with the vast majority...

  20. Microalgal composition and primary production in Arctic sea ice: a seasonal study from Kobbeijord (Kangerluarsunnguaq), West Greenland

    DEFF Research Database (Denmark)

    Mikkelsen, Ditte Marie; Rysgaard, Søren; Glud, Ronnie N.

    2008-01-01

    We investigated the microalgal community in sea ice and in the water column of Kobbefjord, west Greenland, through an entire sea ice season, Temporal variation in physical (photosynthetically active radiation [PAR), temperature, brine volume) and chemical (salinity, nutrient concentration...... (maxima of 1.8 and 2.6 mu g chl](-1) in March and May, respectively). Primary production mirrored biomass dynamic, which had 2 seasonal peaks of ca. 21 and 15 mg Cm-2 d(-1). Integrated primary production over 7 mo was 0.8 g Cm-2 in sea ice and 94.4 g C m(-2) in the water column, with the vast majority......) properties confirmed that sea ice is a very dynamic habitat. Nevertheless, a viable sea ice algal comuunity was present throughout the year, with a species succession from flagellate dominance (dinoflagellates and cryptophytes) in December to February, followed by Chaetoceros simplex (a centric diatom...

  1. Community structure, cellular rRNA content, and activity of sulfate-reducing bacteria in marine Arctic sediments

    DEFF Research Database (Denmark)

    Ravenschlag, K.; Sahm, K.; Knoblauch, C.

    2000-01-01

    The community structure of sulfate-reducing bacteria (SRB) of a marine Arctic sediment (Smeerenburg-fjorden, Svalbard) a-as characterized by both fluorescence in situ hybridization (FISH) and rRNA slot blot hybridization by using group- and genus-specific 16S rRNA-targeted oligonucleotide probes...... that FISH and rRNA slot blot hybridization gave comparable results. Furthermore, a combination of the two methods allowed us to calculate specific cellular rRNA contents with respect to localization in the sediment profile. The rRNA contents of Desulfosarcina-Desulfococcus cells were highest in the first 5...... mm of the sediment (0.9 and 1.4 fg, respectively) and decreased steeply with depth, indicating that maximal metabolic activity occurred close to the surface, Based on SRB cell numbers, cellular sulfate reduction rates were calculated. The rates were highest in the surface layer (0.14 fmol cell(-1...

  2. The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)

    Science.gov (United States)

    Danise, Silvia; Twitchett, Richard J.; Little, Crispin T. S.; Clémence, Marie-Emilie

    2013-01-01

    The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans. PMID:23457537

  3. Enriching distinctive microbial communities from marine sediments via an electrochemical-sulfide-oxidizing process on carbon electrodes

    Directory of Open Access Journals (Sweden)

    Shiue-Lin eLi

    2015-02-01

    Full Text Available Sulfide is a common product of marine anaerobic respiration, and a potent reactant biologically and geochemically. Here we demonstrate the impact on microbial communities with the removal of sulfide via electrochemical methods. The use of differential pulse voltammetry revealed that the oxidation of soluble sulfide was seen at + mV (vs. SHE at all pH ranges tested (from pH = 4 to 8, while non-ionized sulfide, which dominated at pH = 4 was poorly oxidized via this process. Two mixed cultures (CAT and LA were enriched from two different marine sediments (from Catalina Island, CAT; from the Port of Los Angeles, LA in serum bottles using a seawater medium supplemented with lactate, sulfate, and yeast extract, to obtain abundant biomass. Both CAT and LA cultures were inoculated in electrochemical cells (using yeast-extract-free seawater medium as an electrolyte equipped with carbon-felt electrodes. In both cases, when potentials of +630 or 130 mV (vs. SHE were applied, currents were consistently higher at +630 then at 0 mV, indicating more sulfide being oxidized at the higher potential. In addition, higher organic-acid and sulfate conversion rates were found at +630 mV with CAT, while no significant differences were found with LA at different potentials. The results of microbial-community analyses revealed a decrease in diversity for both CAT and LA after electrochemical incubation. In addition, some bacteria (e.g., Clostridium and Arcobacter not well known to be capable of extracellular electron transfer, were found to be dominant in the electrochemical cells. Thus, even though the different mixed cultures have different tolerances for sulfide, electrochemical-sulfide removal can lead to major population changes.

  4. Is benthic food web structure related to diversity of marine macrobenthic communities?

    NARCIS (Netherlands)

    Sokolowski, A.; Wolowicz, M.; Asmus, H.; Asmus, R.; Carlier, A.; Gasiunaite, Z.; Gremare, A.; Hummel, H.; Lesutiene, J.; Razinkovas, A.; Renaud, P.E.; Richard, P.; Kedra, M.

    2012-01-01

    Numerical structure and the organisation of food webs within macrozoobenthic communities has been assessed in the European waters (Svalbard, Barents Sea, Baltic Sea, North Sea, Atlantic Ocean and the Mediterranean Sea) to address the interactions between biodiversity and ecosystem functioning.

  5. Inter- and Intraspecific Variations of Bacterial Communities Associated with Marine Sponges from San Juan Island, Washington

    KAUST Repository

    Lee, O. O.; Wong, Y. H.; Qian, P.-Y.

    2009-01-01

    This study attempted to assess whether conspecific or congeneric sponges around San Juan Island, Washington, harbor specific bacterial communities. We used a combination of culture-independent DNA fingerprinting techniques (terminal restriction

  6. Bacterioplankton: a sink for carbon in a coastal marine plankton community

    International Nuclear Information System (INIS)

    Ducklow, H.W.; Purdie, D.A.; Williams, P.J.LeB.; Davis, J.M.

    1986-01-01

    Recent determinations of high production rates (up to 30% of primary production in surface waters) implicate free-living marine bacterioplankton as a link in a microbial loop that supplements phytoplankton as food for herbivores. An enclosed water column of 300 cubic meters was used to test the microbial loop hypothesis by following the fate of carbon-14-labeled bacterioplankton for over 50 days. Only 2% of the label initially fixed from carbon-14-labeled glucose by bacteria was present in larger organisms after 13 days, at which time about 20% of the total label added remained in the particulate fraction. Most of the label appeared to pass directly from particles smaller than 1 micrometer (heterotrophic bacterioplankton and some bacteriovores) to respired labeled carbon dioxide or to regenerated dissolved organic carbon-14. Secondary (and, by implication, primary) production by organisms smaller than 1 micrometer may not be an important food source in marine food chains. Bacterioplankton can be a sink for carbon in planktonic food webs and may serve principally as agents of nutrient regeneration rather than as food

  7. Recent Trends in Local-Scale Marine Biodiversity Reflect Community Structure and Human Impacts.

    Science.gov (United States)

    Elahi, Robin; O'Connor, Mary I; Byrnes, Jarrett E K; Dunic, Jillian; Eriksson, Britas Klemens; Hensel, Marc J S; Kearns, Patrick J

    2015-07-20

    The modern biodiversity crisis reflects global extinctions and local introductions. Human activities have dramatically altered rates and scales of processes that regulate biodiversity at local scales. Reconciling the threat of global biodiversity loss with recent evidence of stability at fine spatial scales is a major challenge and requires a nuanced approach to biodiversity change that integrates ecological understanding. With a new dataset of 471 diversity time series spanning from 1962 to 2015 from marine coastal ecosystems, we tested (1) whether biodiversity changed at local scales in recent decades, and (2) whether we can ignore ecological context (e.g., proximate human impacts, trophic level, spatial scale) and still make informative inferences regarding local change. We detected a predominant signal of increasing species richness in coastal systems since 1962 in our dataset, though net species loss was associated with localized effects of anthropogenic impacts. Our geographically extensive dataset is unlikely to be a random sample of marine coastal habitats; impacted sites (3% of our time series) were underrepresented relative to their global presence. These local-scale patterns do not contradict the prospect of accelerating global extinctions but are consistent with local species loss in areas with direct human impacts and increases in diversity due to invasions and range expansions in lower impact areas. Attempts to detect and understand local biodiversity trends are incomplete without information on local human activities and ecological context. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Inter- and Intraspecific Variations of Bacterial Communities Associated with Marine Sponges from San Juan Island, Washington

    KAUST Repository

    Lee, O. O.

    2009-04-10

    This study attempted to assess whether conspecific or congeneric sponges around San Juan Island, Washington, harbor specific bacterial communities. We used a combination of culture-independent DNA fingerprinting techniques (terminal restriction fragment length polymorphism and denaturing gradient gel electrophoresis [DGGE]) and culture-dependent approaches. The results indicated that the bacterial communities in the water column consisted of more diverse bacterial ribotypes than and were drastically different from those associated with the sponges. High levels of similarity in sponge-associated bacterial communities were found only in Myxilla incrustans and Haliclona rufescens, while the bacterial communities in Halichondria panicea varied substantially among sites. Certain terminal restriction fragments or DGGE bands were consistently obtained for different individuals of M. incrustans and H. rufescens collected from different sites, suggesting that there are stable or even specific associations of certain bacteria in these two sponges. However, no specific bacterial associations were found for H. panicea or for any one sponge genus. Sequencing of nine DGGE bands resulted in recovery of seven sequences that best matched the sequences of uncultured Proteobacteria. Three of these sequences fell into the sponge-specific sequence clusters previously suggested. An uncultured alphaproteobacterium and a culturable Bacillus sp. were found exclusively in all M. incrustans sponges, while an uncultured gammaproteobacterium was unique to H. rufescens. In contrast, the cultivation approach indicated that sponges contained a large proportion of Firmicutes, especially Bacillus, and revealed large variations in the culturable bacterial communities associated with congeneric and conspecific sponges. This study revealed sponge species-specific but not genus- or site-specific associations between sponges and bacterial communities and emphasized the importance of using a combination

  9. Metabolite Profiling of the Microalgal Diatom Chaetoceros Calcitrans and Correlation with Antioxidant and Nitric Oxide Inhibitory Activities via 1H NMR-Based Metabolomics

    Directory of Open Access Journals (Sweden)

    Awanis Azizan

    2018-05-01

    Full Text Available Microalgae are promising candidate resources from marine ecology for health-improving effects. Metabolite profiling of the microalgal diatom, Chaetoceros calcitrans was conducted by using robust metabolomics tools, namely 1H nuclear magnetic resonance (NMR spectroscopy coupled with multivariate data analysis (MVDA. The unsupervised data analysis, using principal component analysis (PCA, resolved the five types of extracts made by solvents ranging from polar to non-polar into five different clusters. Collectively, with various extraction solvents, 11 amino acids, cholesterol, 6 fatty acids, 2 sugars, 1 osmolyte, 6 carotenoids and 2 chlorophyll pigments were identified. The fatty acids and both carotenoid pigments as well as chlorophyll, were observed in the extracts made from medium polar (acetone, chloroform and non-polar (hexane solvents. It is suggested that the compounds were the characteristic markers that influenced the separation between the clusters. Based on partial least square (PLS analysis, fucoxanthin, astaxanthin, violaxanthin, zeaxanthin, canthaxanthin, and lutein displayed strong correlation to 2,2-diphenyl-1-picrylhydrazyl (DPPH free radical scavenging and nitric oxide (NO inhibitory activity. This metabolomics study showed that solvent extractions are one of the main bottlenecks for the maximum recovery of bioactive microalgal compounds and could be a better source of natural antioxidants due to a high value of metabolites.

  10. Production and decomposition of new DOC by marine plankton communities: carbohydrates, refractory components and nutrient limitation

    DEFF Research Database (Denmark)

    Kragh, T.; Søndergaard, Morten

    2009-01-01

    The accumulation and biodegradation of dissolved organic carbon (DOC) and dissolved and particulate combined neutral sugars (DCNS, PCNS) were followed during a period of 22 days in experimental marine phytoplankton incubations. Five different growth regimes were established in 11 m(3) coastal...... in the mesocosms with diatoms dominating could be explained by DCNS, while only 6% was explained in the mesocosms with few diatoms. PCNS composition was similar in all mesocosms and with dominance of glucose and mannose, while DCNS were more evenly distributed with the following mole percentages fucose 15......, rhamnose 14, arabinose 6, galactose 27, glucose 20 and mannose 18%. The DCNS composition did not reflect the PCNS composition at any time during the experiment. Accumulated DCNS were quickly degraded and only 1% of the new RDOC was explained by DCNS. RDOC accumulated after day #17 in the two mesocosms...

  11. Pharmaceutical Properties of Marine Macroalgal Communities from Gulf of Mannar against Human Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    R. Lavanya

    2012-05-01

    Full Text Available Objective: To evaluate the antifungal activity of seaweed extracts against human fungal pathogens. Methods: Antifungal activity of six species of marine macro algae Codium decorticatum, Caulerpa scalpelliformis, Gracilaria crassa, Acanthophora spicifera, Sargassum wightii and Turbinaria conoides using different solvents acetone, methanol, chloroform, diethyl ether, ethyl acetate, hexane and aqueous were evaluated against Fusarium oxysporum, Fusarium udum, Fusarium solani, Rhizoctonia solani, Alternaria alternat, Botrytis cinerea, Candida albicans, Candida krusei, Aspergillus niger and Aspergillus flavus. Results: From the investigation, the maximum activity was recorded from Phaeophyceae, Chlorophyceae and Rhodophyceae respectively. The maximum inhibition zone was noted in acetone extract of T. conoides against F. udum. Conclusions: From these findings, it is concluded that brown seaweed Turbinaria conoides is more effective than the green and red seaweeds.

  12. Rapid assessment of visual impairment (RAVI in marine fishing communities in South India - study protocol and main findings

    Directory of Open Access Journals (Sweden)

    Madala Sreenivas R

    2011-09-01

    Full Text Available Abstract Background Reliable data are a pre-requisite for planning eye care services. Though conventional cross sectional studies provide reliable information, they are resource intensive. A novel rapid assessment method was used to investigate the prevalence and causes of visual impairment and presbyopia in subjects aged 40 years and older. This paper describes the detailed methodology and study procedures of Rapid Assessment of Visual Impairment (RAVI project. Methods A population-based cross-sectional study was conducted using cluster random sampling in the coastal region of Prakasam district of Andhra Pradesh in India, predominantly inhabited by fishing communities. Unaided, aided and pinhole visual acuity (VA was assessed using a Snellen chart at a distance of 6 meters. The VA was re-assessed using a pinhole, if VA was Results The data collection was completed in Conclusion There is a high prevalence of visual impairment in marine fishing communities in Prakasam district in India. The data from this rapid assessment survey can now be used as a baseline to start eye care services in this region. The rapid assessment methodology (RAVI reported in this paper is robust, quick and has the potential to be replicated in other areas.

  13. Conversion of Uric Acid into Ammonium in Oil-Degrading Marine Microbial Communities: a Possible Role of Halomonads

    KAUST Repository

    Gertler, Christoph; Bargiela, Rafael; Mapelli, Francesca; Han, Xifang; Chen, Jianwei; Hai, Tran; Amer, Ranya A.; Mahjoubi, Mouna; Malkawi, Hanan Issa; Magagnini, Mirko; Cherif, Ameur; Abdel-Fattah, Yasser Refaat; Kalogerakis, Nicolas E.; Daffonchio, Daniele; Ferrer, Manuel; Golyshin, Peter N.

    2015-01-01

    Uric acid is a promising hydrophobic nitrogen source for biostimulation of microbial activities in oil-impacted marine environments. This study investigated metabolic processes and microbial community changes in a series of microcosms using sediment from the Mediterranean and the Red Sea amended with ammonium and uric acid. Respiration, emulsification, ammonium and protein concentration measurements suggested a rapid production of ammonium from uric acid accompanied by the development of microbial communities containing hydrocarbonoclastic bacteria after 3 weeks of incubation. About 80 % of uric acid was converted to ammonium within the first few days of the experiment. Microbial population dynamics were investigated by Ribosomal Intergenic Spacer Analysis and Illumina sequencing as well as by culture-based techniques. Resulting data indicated that strains related to Halomonas spp. converted uric acid into ammonium, which stimulated growth of microbial consortia dominated by Alcanivorax spp. and Pseudomonas spp. Several strains of Halomonas spp. were isolated on uric acid as the sole carbon source showed location specificity. These results point towards a possible role of halomonads in the conversion of uric acid to ammonium utilized by hydrocarbonoclastic bacteria. © 2015 Springer Science+Business Media New York

  14. Conversion of Uric Acid into Ammonium in Oil-Degrading Marine Microbial Communities: a Possible Role of Halomonads

    KAUST Repository

    Gertler, Christoph

    2015-04-29

    Uric acid is a promising hydrophobic nitrogen source for biostimulation of microbial activities in oil-impacted marine environments. This study investigated metabolic processes and microbial community changes in a series of microcosms using sediment from the Mediterranean and the Red Sea amended with ammonium and uric acid. Respiration, emulsification, ammonium and protein concentration measurements suggested a rapid production of ammonium from uric acid accompanied by the development of microbial communities containing hydrocarbonoclastic bacteria after 3 weeks of incubation. About 80 % of uric acid was converted to ammonium within the first few days of the experiment. Microbial population dynamics were investigated by Ribosomal Intergenic Spacer Analysis and Illumina sequencing as well as by culture-based techniques. Resulting data indicated that strains related to Halomonas spp. converted uric acid into ammonium, which stimulated growth of microbial consortia dominated by Alcanivorax spp. and Pseudomonas spp. Several strains of Halomonas spp. were isolated on uric acid as the sole carbon source showed location specificity. These results point towards a possible role of halomonads in the conversion of uric acid to ammonium utilized by hydrocarbonoclastic bacteria. © 2015 Springer Science+Business Media New York

  15. Assessing the effects of marine protected area (MPA) on a reef fish assemblage in a northwestern Mediterranean marine reserve: Identifying community-based indicators

    OpenAIRE

    Claudet, Joachim; Pelletier, Dominique; Jouvenel, J.y; Bachet, F; Galzin, R

    2006-01-01

    Marine protected areas (MPAs) are increasingly envisaged as a tool to manage coastal ecosystems and fisheries. Assessment of their performance with respect to management objectives is therefore important. A number of WAS provided conservation benefits for fished species. Observed benefits do not apply to all species at all times, and responses to protection are also highly variable among fish taxa. Among the many empirical studies on marine reserves, only a few designs considered 'before and ...

  16. Biodiversity links above and below the marine sediment-water interface that may influence community stability

    NARCIS (Netherlands)

    Austen, M.C.; Lambshead, P.J.D.; Hutchings, P.; Boucher, G.; Snelgrove, P.V.R.; Heip, C.H.R.; King, G.; Koike, I.; Smith, C.

    2002-01-01

    Linkages across the sediment-water interface (SWI) between biodiversity and community stability appear to exist but are very poorly studied. Processes by which changes in biodiversity could affect stability on the other side of the SWI include carbon transfer during feeding, decomposition of organic

  17. Influence of plankton community structure on the sinking velocity of marine aggregates

    Science.gov (United States)

    Bach, L. T.; Boxhammer, T.; Larsen, A.; Hildebrandt, N.; Schulz, K. G.; Riebesell, U.

    2016-08-01

    About 50 Gt of carbon is fixed photosynthetically by surface ocean phytoplankton communities every year. Part of this organic matter is reprocessed within the plankton community to form aggregates which eventually sink and export carbon into the deep ocean. The fraction of organic matter leaving the surface ocean is partly dependent on aggregate sinking velocity which accelerates with increasing aggregate size and density, where the latter is controlled by ballast load and aggregate porosity. In May 2011, we moored nine 25 m deep mesocosms in a Norwegian fjord to assess on a daily basis how plankton community structure affects material properties and sinking velocities of aggregates (Ø 80-400 µm) collected in the mesocosms' sediment traps. We noted that sinking velocity was not necessarily accelerated by opal ballast during diatom blooms, which could be due to relatively high porosity of these rather fresh aggregates. Furthermore, estimated aggregate porosity (Pestimated) decreased as the picoautotroph (0.2-2 µm) fraction of the phytoplankton biomass increased. Thus, picoautotroph-dominated communities may be indicative for food webs promoting a high degree of aggregate repackaging with potential for accelerated sinking. Blooms of the coccolithophore Emiliania huxleyi revealed that cell concentrations of 1500 cells/mL accelerate sinking by about 35-40%, which we estimate (by one-dimensional modeling) to elevate organic matter transfer efficiency through the mesopelagic from 14 to 24%. Our results indicate that sinking velocities are influenced by the complex interplay between the availability of ballast minerals and aggregate packaging; both of which are controlled by plankton community structure.

  18. Transcriptome analyses to investigate symbiotic relationships between marine protists

    Science.gov (United States)

    Balzano, Sergio; Corre, Erwan; Decelle, Johan; Sierra, Roberto; Wincker, Patrick; Da Silva, Corinne; Poulain, Julie; Pawlowski, Jan; Not, Fabrice

    2015-01-01

    Rhizaria are an important component of oceanic plankton communities worldwide. A number of species harbor eukaryotic microalgal symbionts, which are horizontally acquired in the environment at each generation. Although these photosymbioses are determinant for Rhizaria ability to thrive in oceanic ecosystems, the mechanisms for symbiotic interactions are unclear. Using high-throughput sequencing technology (i.e., 454), we generated large Expressed Sequence Tag (EST) datasets from four uncultured Rhizaria, an acantharian (Amphilonche elongata), two polycystines (Collozoum sp. and Spongosphaera streptacantha), and one phaeodarian (Aulacantha scolymantha). We assessed the main genetic features of the host/symbionts consortium (i.e., the holobiont) transcriptomes and found rRNA sequences affiliated to a wide range of bacteria and protists in all samples, suggesting that diverse microbial communities are associated with the holobionts. A particular focus was then carried out to search for genes potentially involved in symbiotic processes such as the presence of c-type lectins-coding genes, which are proteins that play a role in cell recognition among eukaryotes. Unigenes coding putative c-type lectin domains (CTLD) were found in the species bearing photosynthetic symbionts (A. elongata, Collozoum sp., and S. streptacantha) but not in the non-symbiotic one (A. scolymantha). More particularly, phylogenetic analyses group CTLDs from A. elongata and Collozoum sp. on a distinct branch from S. streptacantha CTLDs, which contained carbohydrate-binding motifs typically observed in other marine photosymbiosis. Our data suggest that similarly to other well-known marine photosymbiosis involving metazoans, the interactions of glycans with c-type lectins is likely involved in modulation of the host/symbiont specific recognition in Radiolaria. PMID:25852650

  19. The effect of light supply on microalgal growth, CO2 uptake and nutrient removal from wastewater

    International Nuclear Information System (INIS)

    Gonçalves, A.L.; Simões, M.; Pires, J.C.M.

    2014-01-01

    Highlights: • Effect of irradiance and light:dark ratio on microalgal growth was analysed. • Microalgal growth, CO 2 capture, nitrogen and phosphorus uptake were evaluated. • Higher irradiances and light periods supported higher growth and CO 2 uptake rates. • All the studied microalgal strains have shown high nitrogen removal efficiencies. • The highest phosphorus removal efficiency was 67.6%. - Abstract: Microalgal based biofuels have been reported as an attractive alternative for fossil fuels, since they constitute a renewable energy source that reduces greenhouse gas emissions to the atmosphere. However, producing biofuels from microalgae is still not economically viable. Therefore, the integration of biofuel production with other microalgal applications, such as CO 2 capture and nutrient removal from wastewaters, would reduce the microalgal production costs (and the environmental impact of cultures), increasing the economic viability of the whole process. Additionally, producing biofuels from microalgae strongly depends on microalgal strain and culture conditions. This study evaluates the effect of culture conditions, namely light irradiance (36, 60, 120 and 180 μE m −2 s −1 ) and light:dark ratio (10:14, 14:10 and 24:0), on microalgal growth, atmospheric CO 2 uptake and nutrient (nitrogen and phosphorous) removal from culture medium. Four different microalgal strains, Chlorella vulgaris, Pseudokirchneriella subcapitata, Synechocystis salina and Microcystis aeruginosa, were studied to ascertain the most advantageous regarding the referred applications. This study has shown that higher light irradiance values and light periods resulted in higher specific growth rates and CO 2 uptake rates. C. vulgaris presented the highest specific growth rate and CO 2 uptake rate: 1.190 ± 0.041 d −1 and 0.471 ± 0.047 g CO2 L −1 d −1 , respectively. All the strains have shown high nitrogen removal efficiencies, reaching 100% removal percentages in

  20. Role of granular activated carbon in the microalgal cultivation from bacteria contamination.

    Science.gov (United States)

    Ni, Zhi-Yi; Li, Jing-Ya; Xiong, Zhao-Zhao; Cheng, Li-Hua; Xu, Xin-Hua

    2018-01-01

    Microalgal wastewater treatment has been considered as one of the most promising measures to treat nitrogen and phosphorus in the municipal wastewater. While the municipal wastewater provides sufficient nitrogen and phosphorus for microalgal growth, the microalgae still faces serious biological contamination caused by bacteria in wastewater. In this study, the commercial granular activated carbon (GAC) was added into the simulated municipal wastewater to avoid the influence of bacteria on the growth of microalgae. The extracellular organic matter (EOM) in microalgal broth was then characterized to enlighten the role of GAC in reducing the bioavailability of EOM. The results showed that the GAC addition could increase the dry weight of microalgae from 0.06mgL -1 to 0.46mgL -1 under the condition of bacterial inoculation. The GAC could mitigate bacterial contamination mainly due to its adsorption of both bacteria and EOM that might contain algicidal extracellular substances. Moreover, compared to the control group, the GAC addition could mitigate the microalgal lysis caused by bacteria and thus greatly reduce the bioavailability of EOM from 2.80mgL -1 to 0.61mgL -1 , which was beneficial for the improvement of biostability and reuse of effluent after the microalgal harvesting. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Nutrient removal and biomass production: advances in microalgal biotechnology for wastewater treatment.

    Science.gov (United States)

    Abinandan, Sudharsanam; Subashchandrabose, Suresh R; Venkateswarlu, Kadiyala; Megharaj, Mallavarapu

    2018-05-17

    Owing to certain drawbacks, such as energy-intensive operations in conventional modes of wastewater treatment (WWT), there has been an extensive search for alternative strategies in treatment technology. Biological modes for treating wastewaters are one of the finest technologies in terms of economy and efficiency. An integrated biological approach with chemical flocculation is being conventionally practiced in several-sewage and effluent treatment plants around the world. Overwhelming responsiveness to treat wastewaters especially by using microalgae is due to their simplest photosynthetic mechanism and ease of acclimation to various habitats. Microalgal technology, also known as phycoremediation, has been in use for WWT since 1950s. Various strategies for the cultivation of microalgae in WWT systems are evolving faster. However, the availability of innovative approaches for maximizing the treatment efficiency, coupled with biomass productivity, remains the major bottleneck for commercialization of microalgal technology. Investment costs and invasive parameters also delimit the use of microalgae in WWT. This review critically discusses the merits and demerits of microalgal cultivation strategies recently developed for maximum pollutant removal as well as biomass productivity. Also, the potential of algal biofilm technology in pollutant removal, and harvesting the microalgal biomass using different techniques have been highlighted. Finally, an economic assessment of the currently available methods has been made to validate microalgal cultivation in wastewater at the commercial level.

  2. Marine Science

    African Journals Online (AJOL)

    sustainable coastal development in the region, as well as contributing to the ... between humans and the coastal and marine environment. ... exploitation for timber, fuel wood, aquaculture, urban. Abstract. Given the high dependence of coastal communities on natural resources, mangrove conservation is a challenge in.

  3. Structural changes of marine communities over the Permian-Triassic transition: Ecologically assessing the end-Permian mass extinction and its aftermath

    Science.gov (United States)

    Chen, Zhong-Qiang; Tong, Jinnan; Liao, Zhuo-Ting; Chen, Jing

    2010-08-01

    The Permian/Triassic (P/Tr) transition is ecologically assessed based on examining 23 shelly communities from five shallow platform, ramp and shelf basin facies Permian-Triassic boundary (PTB) sections in South China. The shelly communities have undergone two major collapses coinciding with the two episodes of the end-Permian mass extinction. The first P/Tr extinction event devastated shelly communities in all types of settings to some extent. The basin communities have been more severely impacted than both platform and ramp communities. The survival faunas have rebounded more rapidly in shallow niches than in relatively deep habitats. The second P/Tr crisis destroyed the survival communities in shallow setting and had little impact on the basin communities in terms of community structures. The early Griesbachian communities are overall low-diversity and high-dominance. The governorship switch from brachiopods to bivalves in marine communities has been facilitated by two pulses of the end-Permian mass extinction and the whole takeover process took about 200 ka across the P/Tr boundary. Bivalve ecologic takeover initially occurred immediately after the first P/Tr extinction in shallow water habitats and was eventually completed in all niches after the second P/Tr event. Some post-extinction communities have the irregular rarefaction curves due to the unusual community structures rather than sampling intensities.

  4. The Ever-Est Virtual Research Environment Infrastructure for Marine - the Sea Monitoring Virtual Research Community (vrc) Use Case

    Science.gov (United States)

    Foglini, F.

    2016-12-01

    The EVER-EST project aims to develop a generic Virtual Research Environment (VRE) tailored to the needs and validated by the Earth Science domain. To achieve this the EVER-EST VRE provides earth scientists with the means to seamlessly manage both the data involved in their computationally intensive disciplines and the scientific methods applied in their observations and modellings, which lead to the specific results that need to be attributable, validated and shared within the community e.g. in the form of scholarly communications. Central to this approach is the concept of Research Objects (ROs) as semantically rich aggregations of resources that bring together data, methods and people in scientific investigations. ROs enable the creation of digital artifacts that can encapsulate scientific knowledge and provide a mechanism for sharing and discovering assets of reusable research and scientific assets as first-class citizens. The EVER-EST VRE is the first RO-centric native infrastructure leveraging the notion of ROs and their application in observational rather than experimental disciplines and particularly in Earth Science. The Institute of MARine Science (ISMAR-CNR) is a scientific partner of the EVER-EST project providing useful and applicable contributions to the identification and definition of variables indicated by the European Commission in the Marine Strategy Framework Directive (MSFD) to achieve the Good Environment Status (GES). The VRC is willing to deliver practical methods, procedures and protocols to support coherent and widely accepted interpretation of the MSFD. The use case deal with 1. the Posidonia meadows along the Apulian coast, 2. the deep-sea corals along the Apulian continenatal slope and 3. the jellyfish abundance in the Italian water. The SeaMonitoring VRC created specific RO for asesing deep sea corals suitabilty, Posidonia meadows occurrences and for detecting jelly fish density aloing the italian coast. The VRC developed specific RO

  5. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria.

    Science.gov (United States)

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

    2012-11-01

    Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetate-utilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 10(6) acetate-utilizing manganese-reducing cells cm(-3) in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetate-dependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments.

  6. Enrichment of marine anammox bacteria from seawater-related samples and bacterial community study.

    Science.gov (United States)

    Kawagoshi, Y; Nakamura, Y; Kawashima, H; Fujisaki, K; Furukawa, K; Fujimoto, A

    2010-01-01

    Anaerobic ammonium oxidation (anammox) is a novel nitrogen pathway catalyzed by anammox bacteria which are obligate anaerobic chemoautotrophs. In this study, enrichment culture of marine anammox bacteria (MAAOB) from the samples related to seawater was conducted. Simultaneous removal of ammonium and nitrite was confirmed in continuous culture inoculated with sediment of a sea-based waste disposal site within 50 days. However, no simultaneous nitrogen removal was observed in cultures inoculated with seawater-acclimated denitrifying sludge or with muddy sediment of tideland even during 200 days. Nitrogen removal rate of 0.13 kg/m(3)/day was achieved at nitrogen loading rate of 0.16 kg/m(3)/day after 320th days in the culture inoculated with the sediment of waste disposal site. The nitrogen removal ratio between ammonium nitrogen and nitrite nitrogen was 1:1.07. Denaturing gradient gel electrophoresis (DGGE) analysis indicated that an abundance of the bacteria close to MAAOB and coexistence of ammonium oxidizing bacteria and denitrifying bacteria in the culture.

  7. The effect of surface colour on the formation of marine micro and macrofouling communities.

    Science.gov (United States)

    Dobretsov, Sergey; Abed, Raeid M M; Voolstra, Christian R

    2013-01-01

    The effect of substratum colour on the formation of micro- and macro fouling communities was investigated. Acrylic tiles, painted either black or white were covered with transparent sheets in order to ensure similar surface properties. All substrata were exposed to biofouling at 1 m depth for 40 d in the Marina Bandar al Rowdha (Muscat, Sea of Oman). Studies were conducted in 2010 over a time course of 5, 10 and 20 d, and in 2012 samples were collected at 7, 14 and 21 d. The densities of bacteria on the black and white substrata were similar with the exception of day 10, when the black substrata had a higher abundance than white ones. Pyrosequencing via 454 of 16S rRNA genes of bacteria from white and black substrata revealed that Alphaproteobacteria and Firmicutes were the dominant groups. SIMPER analysis demonstrated that bacterial phylotypes (uncultured Gammaproteobacteria, Actibacter, Gaetbulicola, Thalassobius and Silicibacter) and the diatoms (Navicula directa, Navicula sp. and Nitzschia sp.) contributed to the dissimilarities between communities developed on white and black substrata. At day 20, the highest amount of chlorophyll a was recorded in biofilms developed on black substrata. SIMPER analysis showed that Folliculina sp., Ulva sp. and Balanus amphitrite were the major macro fouling species that contributed to the dissimilarities between the communities formed on white and black substrata. Higher densities of these species were observed on black tiles. The results emphasise the effect of substratum colour on the formation of micro and macro fouling communities; substratum colour should to be taken into account in future studies.

  8. The effect of surface colour on the formation of marine micro and macrofouling communities

    KAUST Repository

    Dobretsov, Sergey V.; Abed, Raeid M M; Voolstra, Christian R.

    2013-01-01

    The effect of substratum colour on the formation of micro- and macro fouling communities was investigated. Acrylic tiles, painted either black or white were covered with transparent sheets in order to ensure similar surface properties. All substrata were exposed to biofouling at 1 m depth for 40 d in the Marina Bandar al Rowdha (Muscat, Sea of Oman). Studies were conducted in 2010 over a time course of 5, 10 and 20 d, and in 2012 samples were collected at 7, 14 and 21 d. The densities of bacteria on the black and white substrata were similar with the exception of day 10, when the black substrata had a higher abundance than white ones. Pyrosequencing via 454 of 16S rRNA genes of bacteria from white and black substrata revealed that Alphaproteobacteria and Firmicutes were the dominant groups. SIMPER analysis demonstrated that bacterial phylotypes (uncultured Gammaproteobacteria, Actibacter, Gaetbulicola, Thalassobius and Silicibacter) and the diatoms (Navicula directa, Navicula sp. and Nitzschia sp.) contributed to the dissimilarities between communities developed on white and black substrata. At day 20, the highest amount of chlorophyll a was recorded in biofilms developed on black substrata. SIMPER analysis showed that Folliculina sp., Ulva sp. and Balanus amphitrite were the major macro fouling species that contributed to the dissimilarities between the communities formed on white and black substrata. Higher densities of these species were observed on black tiles. The results emphasise the effect of substratum colour on the formation of micro and macro fouling communities; substratum colour should to be taken into account in future studies. © 2013 Copyright Taylor and Francis Group, LLC.

  9. The effect of surface colour on the formation of marine micro and macrofouling communities

    KAUST Repository

    Dobretsov, Sergey V.

    2013-07-01

    The effect of substratum colour on the formation of micro- and macro fouling communities was investigated. Acrylic tiles, painted either black or white were covered with transparent sheets in order to ensure similar surface properties. All substrata were exposed to biofouling at 1 m depth for 40 d in the Marina Bandar al Rowdha (Muscat, Sea of Oman). Studies were conducted in 2010 over a time course of 5, 10 and 20 d, and in 2012 samples were collected at 7, 14 and 21 d. The densities of bacteria on the black and white substrata were similar with the exception of day 10, when the black substrata had a higher abundance than white ones. Pyrosequencing via 454 of 16S rRNA genes of bacteria from white and black substrata revealed that Alphaproteobacteria and Firmicutes were the dominant groups. SIMPER analysis demonstrated that bacterial phylotypes (uncultured Gammaproteobacteria, Actibacter, Gaetbulicola, Thalassobius and Silicibacter) and the diatoms (Navicula directa, Navicula sp. and Nitzschia sp.) contributed to the dissimilarities between communities developed on white and black substrata. At day 20, the highest amount of chlorophyll a was recorded in biofilms developed on black substrata. SIMPER analysis showed that Folliculina sp., Ulva sp. and Balanus amphitrite were the major macro fouling species that contributed to the dissimilarities between the communities formed on white and black substrata. Higher densities of these species were observed on black tiles. The results emphasise the effect of substratum colour on the formation of micro and macro fouling communities; substratum colour should to be taken into account in future studies. © 2013 Copyright Taylor and Francis Group, LLC.

  10. Effect of microalgal treatments on pesticides in water.

    Science.gov (United States)

    Hultberg, Malin; Bodin, Hristina; Ardal, Embla; Asp, Håkan

    2016-01-01

    The effect of the microalgae Chlorella vulgaris on a wide range of different pesticides in water was studied. Treatments included short-term exposure (1 h) to living and dead microalgal biomass and long-term exposure (4 days) to actively growing microalgae. The initial pesticide concentration was 63.5 ± 3.9 µg L(-1). There was no significant overall reduction of pesticides after short-term exposure. A significant reduction of the total amount of pesticides was achieved after the long-term exposure to growing microalgae (final concentration 29.7 ± 1.0 µg L(-1)) compared with the long-term control (37.0 ± 1.2 µg L(-1)). The concentrations of 10 pesticides out of 38 tested were significantly lowered in the long-term algal treatment. A high impact of abiotic factors such as sunlight and aeration for pesticide reduction was observed when the initial control (63.5 ± 3.9 µg L(-1)) and the long-term control (37.0 ± 1.2 µg L(-1)) were compared. The results suggest that water treatment using microalgae, natural inhabitants of polluted surface waters, could be further explored not only for removal of inorganic nutrients but also for removal of organic pollutants in water.

  11. Aggregate formation affects ultrasonic disruption of microalgal cells.

    Science.gov (United States)

    Wang, Wei; Lee, Duu-Jong; Lai, Juin-Yih

    2015-12-01

    Ultrasonication is a cell disruption process of low energy efficiency. This study dosed K(+), Ca(2+) and Al(3+) to Chlorella vulgaris cultured in Bold's Basal Medium at 25°C and measured the degree of cell disruption under ultrasonication. Adding these metal ions yielded less negatively charged surfaces of cells, while with the latter two ions large and compact cell aggregates were formed. The degree of cell disruption followed: control=K(+)>Ca(2+)>Al(3+) samples. Surface charges of cells and microbubbles have minimal effects on the microbubble number in the proximity of the microalgal cells. Conversely, cell aggregates with large size and compact interior resist cell disruption under ultrasonication. Staining tests revealed high diffusional resistance of stains over the aggregate interior. Microbubbles may not be effective generated and collapsed inside the compact aggregates, hence leading to low cell disruption efficiencies. Effective coagulation/flocculation in cell harvesting may lead to adverse effect on subsequent cell disruption efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Nanocellulose size regulates microalgal flocculation and lipid metabolism

    Science.gov (United States)

    Yu, Sun Il; Min, Seul Ki; Shin, Hwa Sung

    2016-01-01

    Harvesting of microalgae is a cost-consuming step for biodiesel production. Cellulose has recently been studied as a biocompatible and inexpensive flocculant for harvesting microalgae via surface modifications such as cation-modifications. In this study, we demonstrated that cellulose nanofibrils (CNF) played a role as a microalgal flocculant via its network geometry without cation modification. Sulfur acid-treated tunicate CNF flocculated microalgae, but cellulose nanocrystals (CNC) did not. In addition, desulfurization did not significantly influence the flocculation efficiency of CNF. This mechanism is likely related to encapsulation of microalgae by nanofibrous structure formation, which is derived from nanofibrils entanglement and intra-hydrogen bonding. Moreover, flocculated microalgae were subject to mechanical stress resulting in changes in metabolism induced by calcium ion influx, leading to upregulated lipid synthesis. CNF do not require surface modifications such as cation modified CNC and flocculation is derived from network geometry related to nanocellulose size; accordingly, CNF is one of the least expensive cellulose-based flocculants ever identified. If this flocculant is applied to the biodiesel process, it could decrease the cost of harvest, which is one of the most expensive steps, while increasing lipid production. PMID:27796311

  13. Treatment of cattle-slaughterhouse wastewater and the reuse of sludge for biodiesel production by microalgal heterotrophic bioreactors

    Directory of Open Access Journals (Sweden)

    Mariana Manzoni Maroneze

    2014-12-01

    Full Text Available Microalgal heterotrophic bioreactors are a potential technological development that can convert organic matter, nitrogen and phosphorus of wastewaters into a biomass suitable for energy production. The aim of this work was to evaluate the performance of microalgal heterotrophic bioreactors in the secondary treatment of cattle-slaughterhouse wastewater and the reuse of microalgal sludge for biodiesel production. The experiments were performed in a bubble column bioreactor using the microalgae Phormidium sp. Heterotrophic microalgal bioreactors removed 90 % of the chemical oxygen demand, 57 % of total nitrogen and 52 % of total phosphorus. Substantial microalgal sludge is produced in the process (substrate yield coefficient of 0.43 mg sludge mg chemical oxygen demand−¹, resulting in a biomass with high potential for producing biodiesel (ester content of more than 99 %, cetane number of 55, iodine value of 73.5 g iodine 100 g−¹, unsaturation degree of ~75 % and a cold filter plugging point of 5 ºC.

  14. Modeling Microalgal Biosediment Formation Based on Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Monitoring.

    Science.gov (United States)

    Ogburn, Zachary L; Vogt, Frank

    2018-03-01

    With increasing amounts of anthropogenic pollutants being released into ecosystems, it becomes ever more important to understand their fate and interactions with living organisms. Microalgae play an important ecological role as they are ubiquitous in marine environments and sequester inorganic pollutants which they transform into organic biomass. Of particular interest in this study is their role as a sink for atmospheric CO 2 , a greenhouse gas, and nitrate, one cause of harmful algal blooms. Novel chemometric hard-modeling methodologies have been developed for interpreting phytoplankton's chemical and physiological adaptations to changes in their growing environment. These methodologies will facilitate investigations of environmental impacts of anthropogenic pollutants on chemical and physiological properties of marine microalgae (here: Nannochloropsis oculata). It has been demonstrated that attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy can gain insights into both and this study only focuses on the latter. From time-series of spectra, the rate of microalgal biomass settling on top of a horizontal ATR element is derived which reflects several of phytoplankton's physiological parameters such as growth rate, cell concentrations, cell size, and buoyancy. In order to assess environmental impacts on such parameters, microalgae cultures were grown under 25 different chemical scenarios covering 200-600 ppm atmospheric CO 2 and 0.35-0.75 mM dissolved NO 3 - . After recording time-series of ATR FT-IR spectra, a multivariate curve resolution-alternating least squares (MCR-ALS) algorithm extracted spectroscopic and time profiles from each data set. From the time profiles, it was found that in the considered concentration ranges only NO 3 - has an impact on the cells' physiological properties. In particular, the cultures' growth rate has been influenced by the ambient chemical conditions. Thus, the presented spectroscopic

  15. PENGEMBANGAN MARINE ECOTOURISM “BONTANG KUALA” MELALUI COMMUNITY DEVELOPMENT PT BADAK NGL

    Directory of Open Access Journals (Sweden)

    Hermansyah Hermansyah

    2017-06-01

    Full Text Available Tujuan yang ingin dicapai dalam penelitian ini adalah penyusunan model pengembangan wisata serta penyusunan strategi dalam upaya pengembangan objek wisata Bontang Kuala. Jenis penelitian ini adalah deskriptif kualitatif, di mana data yang digunakan adalah data primer dan pengambilan data dilakukan dengan observasi, deep interview, dan Focus Group Discussion. Analisis yang digunakan adalah analisis deskriptif dan SWOT. Hasil penelitian menunjukkan model pengembangan desa wisata berbasis marine ecotourism dapat dilakukan dengan melakukan pengembangan potensi wilayah. Pengembangan wisata harus didukung oleh masyarakat dan lembaga baik pemerintah maupun swasta. Dari sisi masyarakat, perlu adanya pembentukan kelompok pengurus objek wisata yang fokus melakukan upaya pemeliharaan lingkungan dan pengelolaannya. Dalam melakukan fungsinya, kelompok tersebut harus menyusun struktur organisasi dan membuat inovasi untuk menjual dan memasarkan objek wisata. Adapun support kelembagaan dan kelompok organisasi pengelola harus mencapai tahap branding dan promosi. Evaluasi secara berkala juga harus dilakukan untuk memonitoring manfaat dan kendala yang dihadapi. Beberapa strategi pengembangan Bontang Kuala di antaranya adalah: peningkatan sinergi antara masyarakat, kelompok MASKAPEI, sektor swasta dan pemerintah dalam pengembangan objek wisata; ekspose keindahan di Bontang Kuala pada masyarakat nasional dan internasional; penciptaan sikap masyarakat sadar wisata; penguatan kapasitas pengelolaan wisata;  penguatan kerjasama pemerintah dan swasta dalam penyedian infrastruktur; inovasi daur ulang sampah; inovasi di bidang promosi dan pemasaran; peningkatan pendampingan pengembangan objek wisata; pemasaran produk UMKM sebagai cinderamata; konservasi alam, budaya, dan pendidikan lingkungan; sosialisasi pada masyarakat dan wisatawan untuk peningkatan kesadaran merawat lingkungan objek wisata; penciptaan branding Bontang Kuala; inovasi pengolahan limbah; memposisikan

  16. Oxidation of urea-derived nitrogen by thaumarchaeota-dominated marine nitrifying communities.

    Science.gov (United States)

    Tolar, Bradley B; Wallsgrove, Natalie J; Popp, Brian N; Hollibaugh, James T

    2017-12-01

    Urea nitrogen has been proposed to contribute significantly to nitrification by marine thaumarchaeotes. These inferences are based on distributions of thaumarchaeote urease genes rather than activity measurements. We found that ammonia oxidation rates were always higher than oxidation rates of urea-derived N in samples from coastal Georgia, USA (means ± SEM: 382 ± 35 versus 73 ± 24 nmol L -1  d -1 , Mann-Whitney U-test p  0.05). Urea-derived N was relatively more important in samples from Antarctic continental shelf waters, though the difference was not statistically significant (19.4 ± 4.8 versus 12.0 ± 2.7 nmol L -1  d -1 , p > 0.05). We found only weak correlations between oxidation rates of urea-derived N and the abundance or transcription of putative Thaumarchaeota ureC genes. Dependence on urea-derived N does not appear to be directly related to pH or ammonium concentrations. Competition experiments and release of 15 NH 3 suggest that urea is hydrolyzed to ammonia intracellularly, then a portion is lost to the dissolved pool. The contribution of urea-derived N to nitrification appears to be minor in temperate coastal waters, but may represent a significant portion of the nitrification flux in Antarctic coastal waters. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. Sampling design for long-term regional trends in marine rocky intertidal communities

    Science.gov (United States)

    Irvine, Gail V.; Shelley, Alice

    2013-01-01

    Probability-based designs reduce bias and allow inference of results to the pool of sites from which they were chosen. We developed and tested probability-based designs for monitoring marine rocky intertidal assemblages at Glacier Bay National Park and Preserve (GLBA), Alaska. A multilevel design was used that varied in scale and inference. The levels included aerial surveys, extensive sampling of 25 sites, and more intensive sampling of 6 sites. Aerial surveys of a subset of intertidal habitat indicated that the original target habitat of bedrock-dominated sites with slope ≤30° was rare. This unexpected finding illustrated one value of probability-based surveys and led to a shift in the target habitat type to include steeper, more mixed rocky habitat. Subsequently, we evaluated the statistical power of different sampling methods and sampling strategies to detect changes in the abundances of the predominant sessile intertidal taxa: barnacles Balanomorpha, the mussel Mytilus trossulus, and the rockweed Fucus distichus subsp. evanescens. There was greatest power to detect trends in Mytilus and lesser power for barnacles and Fucus. Because of its greater power, the extensive, coarse-grained sampling scheme was adopted in subsequent years over the intensive, fine-grained scheme. The sampling attributes that had the largest effects on power included sampling of “vertical” line transects (vs. horizontal line transects or quadrats) and increasing the number of sites. We also evaluated the power of several management-set parameters. Given equal sampling effort, sampling more sites fewer times had greater power. The information gained through intertidal monitoring is likely to be useful in assessing changes due to climate, including ocean acidification; invasive species; trampling effects; and oil spills.

  18. Enrichment of the hydrogen-producing microbial community from marine intertidal sludge by different pretreatment methods

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongyan [Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Shinan District, Qingdao 266071, Shandong (China); College of Marine Science and Engineering, University of Science and Technology, Tianjin 300457 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Wang, Guangce [Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Shinan District, Qingdao 266071, Shandong (China); College of Marine Science and Engineering, University of Science and Technology, Tianjin 300457 (China); Zhu, Daling; Pan, Guanghua [College of Marine Science and Engineering, University of Science and Technology, Tianjin 300457 (China)

    2009-12-15

    To determine the effects of pretreatment on hydrogen production and the hydrogen-producing microbial community, we treated the sludge from the intertidal zone of a bathing beach in Tianjin with four different pretreatment methods, including acid treatment, heat-shock, base treatment as well as freezing and thawing. The results showed that acid pretreatment significantly promoted the hydrogen production by sludge and provided the highest efficiency of hydrogen production among the four methods. The efficiency of the hydrogen production of the acid-pretreated sludge was 0.86 {+-} 0.07 mol H{sub 2}/mol glucose (mean {+-} S.E.), whereas that of the sludge treated with heat-shock, freezing and thawing, base method and control was 0.41 {+-} 0.03 mol H{sub 2}/mol glucose, 0.17 {+-} 0.01 mol H{sub 2}/mol glucose, 0.11 {+-} 0.01 mol H{sub 2}/mol glucose and 0.20 {+-} 0.04 mol H{sub 2}/mol glucose, respectively. The result of denaturing gradient gel electrophoresis (DGGE) showed that pretreatment methods altered the composition of the microbial community that accounts for hydrogen production. Acid and heat pretreatments were favorable to enrich the dominant hydrogen-producing bacterium, i.e. Clostridium sp., Enterococcus sp. and Bacillus sp. However, besides hydrogen-producing bacteria, much non-hydrogen-producing Lactobacillus sp. was also found in the sludge pretreated with base, freezing and thawing methods. Therefore, based on our results, we concluded that, among the four pretreatment methods using acid, heat-shock, base or freezing and thawing, acid pretreatment was the most effective method for promoting hydrogen production of microbial community. (author)

  19. Optimal processing pathway for the production of biodiesel from microalgal biomass: A superstructure based approach

    DEFF Research Database (Denmark)

    Rizwan, Muhammad; Lee, Jay H.; Gani, Rafiqul

    2013-01-01

    In this study, we propose a mixed integer nonlinear programming (MINLP) model for superstructure based optimization of biodiesel production from microalgal biomass. The proposed superstructure includes a number of major processing steps for the production of biodiesel from microalgal biomass......, such as the harvesting of microalgal biomass, pretreatments including drying and cell disruption of harvested biomass, lipid extraction, transesterification, and post-transesterfication purification. The proposed model is used to find the optimal processing pathway among the large number of potential pathways that exist...... for the production of biodiesel from microalgae. The proposed methodology is tested by implementing on a specific case with different choices of objective functions. The MINLP model is implemented and solved in GAMS using a database built in Excel. The results from the optimization are analyzed...

  20. Structure of hydrocarbonoclastic nitrate-reducing bacterial communities in bioturbated coastal marine sediments.

    Science.gov (United States)

    Stauffert, Magalie; Cravo-Laureau, Cristiana; Duran, Robert

    2014-09-01

    The organisation of denitrifying microorganisms in oil-polluted bioturbated sediments was investigated in mesocosms under conditions as closer as possible to that observed in the environment. Molecular and culture-dependent approaches revealed that denitrifying Gammaproteobacteria were abundant in oil-polluted and bioturbated sediments suggesting that they may play a key role in hydrocarbon degradation in the environment. T-RFLP and gene libraries analyses targeting nirS gene showed that denitrifying microbial communities structure was slightly affected by either the addition of Hediste diversicolor or crude oil revealing the metabolic versatility of denitrifying microorganisms. From oil-polluted sediments, distinct denitrifying hydrocarbonoclastic bacterial consortia were obtained by enrichment cultures on high molecular weight polyaromatic hydrocarbons (PAHs) (dibenzothiophene, fluoranthene, pyrene and chrysene) under nitrate-reducing conditions. Interestingly, molecular characterisation of the consortia showed that the denitrifying communities obtained from oiled microcosms with addition of H. diversicolor were different to that observed without H. diversicolor addition, especially with fluoranthene and chrysene revealing the bacterial diversity involved in the degradation of these PAHs. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  1. A trait-based approach to understanding marine communities composition, assembly and diversity

    DEFF Research Database (Denmark)

    Pécuchet, Lauréne

    are characterised by their taxonomic diversity, such as their species richness or the evenness in their abundances. However, there is growing evidence that it is not the taxonomic identity of the species per se that control its presence and abundance in a given environment but its characteristics. Species traits......, we studied the diversity and the processes influencing the composition of demersal fish communities in the Baltic Sea. While species richness was sharply decreasing from the saline Kattegat to the brackish Gdansk Bay, trait richness tended to decrease at a lower rate. We found that the species co...... acting on the species. The strategies’ prevalence exhibited strong geographical patterns which could be explained by spatial variability in annual sea surface temperature, temperature seasonality, depth and fishing intensity. Due to their tight coupling to the environment, notably temperature and fishing...

  2. Epilithic Cyanobacterial Communities of a Marine Tropical Beach Rock (Heron Island, Great Barrier Reef): Diversity and Diazotrophy▿

    Science.gov (United States)

    Díez, Beatriz; Bauer, Karolina; Bergman, Birgitta

    2007-01-01

    The diversity and nitrogenase activity of epilithic marine microbes in a Holocene beach rock (Heron Island, Great Barrier Reef, Australia) with a proposed biological calcification “microbialite” origin were examined. Partial 16S rRNA gene sequences from the dominant mat (a coherent and layered pink-pigmented community spread over the beach rock) and biofilms (nonstratified, differently pigmented microbial communities of small shallow depressions) were retrieved using denaturing gradient gel electrophoresis (DGGE), and a clone library was retrieved from the dominant mat. The 16S rRNA gene sequences and morphological analyses revealed heterogeneity in the cyanobacterial distribution patterns. The nonheterocystous filamentous genus Blennothrix sp., phylogenetically related to Lyngbya, dominated the mat together with unidentified nonheterocystous filaments of members of the Pseudanabaenaceae and the unicellular genus Chroococcidiopsis. The dominance and three-dimensional intertwined distribution of these organisms were confirmed by nonintrusive scanning microscopy. In contrast, the less pronounced biofilms were dominated by the heterocystous cyanobacterial genus Calothrix, two unicellular Entophysalis morphotypes, Lyngbya spp., and members of the Pseudanabaenaceae family. Cytophaga-Flavobacterium-Bacteroides and Alphaproteobacteria phylotypes were also retrieved from the beach rock. The microbial diversity of the dominant mat was accompanied by high nocturnal nitrogenase activities (as determined by in situ acetylene reduction assays). A new DGGE nifH gene optimization approach for cyanobacterial nitrogen fixers showed that the sequences retrieved from the dominant mat were related to nonheterocystous uncultured cyanobacterial phylotypes, only distantly related to sequences of nitrogen-fixing cultured cyanobacteria. These data stress the occurrence and importance of nonheterocystous epilithic cyanobacteria, and it is hypothesized that such epilithic cyanobacteria

  3. Effects of hydrocarbon contamination on a free living marine nematode community: Results from microcosm experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudi, E.; Essid, N.; Beyrem, H.; Hedfi, A.; Boufahja, F.; Aissa, P. [Laboratoire de Biosurveillance de l' Environnement, Zarzouna (Tunisia). Faculte des Sciences de Bizerte; Vitiello, P. [Centre d' Oceanologie de Marseille (France)

    2005-11-15

    Anthropogenic inputs of crude and refined petroleum hydrocarbons into the sea require knowledge of the effects of these contaminants on the receiving assemblages of organisms. A microcosm experiment was carried out to study the influence of diesel on a free living nematode community of a Tunisian lagoon. Sediments were contaminated by diesel that ranged in concentration from 0.5 to 20 mg diesel kg{sup -1} dry weight (dw), and effects were examined after 90 days. Gradual changes in community structure were revealed depending on the quantity of diesel administrated. In the medium (1 mg diesel kg{sup -1} and 5 mg diesel kg{sup -1} (dw)) and high (10 mg diesel kg{sup -1}, 15 mg diesel kg{sup -1} and 20 mg kg{sup -1} (dw)) treated microcosms, most univariate measures, including diversity and species richness, decreased significantly with increasing level of diesel contamination whereas nematode assemblage from the low treated microcosm (0.5 mg diesel kg{sup -1} (dw)) remained unaffected. Results from multivariate analyses of the species abundance data demonstrated that responses of nematode species to the diesel treatments were varied: Chaetonema sp. was eliminated at all doses tested and seemed to be intolerant species to diesel contamination; Pomponema sp. and Oncholaimus campylocercoides were significantly affected at all diesel contamination levels but they were not eliminated, these species were categorized as 'diesel-sensitive'; Hypodontolaimus colesi, Daptonema trabeculosum and Daptonema fallax which significantly increased respectively at 0.5, 1 and 5 mg diesel kg{sup -1} (dw) concentrations and appeared to be 'opportunistic' species at these doses whereas Marylynnia stekhoveni which increased at all high doses (10, 15 and 20 mg diesel kg{sup -1} (dw)) seemed to be a 'diesel-resistant' species. (author)

  4. Rhythmic behaviour of marine benthopelagic species and the synchronous dynamics of benthic communities

    Science.gov (United States)

    Aguzzi, Jacopo; Sbragaglia, Valerio; Tecchio, Samuele; Navarro, Joan; Company, Joan B.

    2015-01-01

    Light-intensity cycles drive the relentless motion of species in the oceans, and water column migrants may cyclically make contact with the seabed, hence influencing the temporal dynamism of benthic ecosystems. The influence of light on this process remains largely unknown to date. In this study, we focus on the occurrence of day-night changes in benthic communities on the western Mediterranean continental shelf (100 m depth) and slope (400 m depth) as a potential result of a behaviourally sustained benthopelagic coupling. We analysed fluctuations in species abundance based on trawling at hourly intervals over a 4-day period as a proxy of activity rhythms at the seabed. We also measured light in situ to assess how the depth-related decrease of its intensity influences species rhythms and the occurrence of the putative benthopelagic synchronisation. Temporal similarities in the catch patterns for different species were screened by dendrogram analysis. On the continental shelf, species performing diel migrations (i.e., over a 24 h period) that were either vertical (i.e., benthopelagic) or horizontal across depths (i.e., nektobenthic) clustered together separately from the more sedentary endobenthic and epibenthic species. At the same depth, waveform analysis showed a significant diurnal increase in the catch of water column species and benthic species at night. Such coupling was absent on the continental slope, where light intensity was several orders of magnitude lower than that on the shelf. Our data indicate that diel activity rhythms, which are well known for vertical pelagic migrators, are also evident in the benthos. We discuss the role of light as a major evolutionary driver shaping the composition and biodiversity of benthic communities via visual predation.

  5. Informatics and Decisions support in Galway Bay (SmartBay) using ERDDAP, OGC Technologies and Third Party Data Sources to Provide Services to the Marine Community.

    Science.gov (United States)

    Delaney, Conor; Gaughan, Paul; Smyth, Damian

    2013-04-01

    of Galway Bay, Ireland. The architecture of the MAST is based on the concepts of Representational State Transfer (REST), Resource Orientated Architecture (ROA), Service Orientated Architecture (SOA), OpenData and MASHUPS. In this paper we demonstrate the architecture of the MAST system and discuss the potential of ERDDAP technology to serve complex data in formats that are accessible to the general developer community. We also discuss of the potential of next generation web technologies and OpenData to encourage the use of valuable marine data resources.

  6. Diversity of Microbial Communities and Quantitative Chemodiversity in Layers of Marine Sediment Cores from a Causeway (Kaichu-Doro in Okinawa Island, Japan

    Directory of Open Access Journals (Sweden)

    Taha Soliman

    2017-12-01

    Full Text Available Microbial community diversity and chemodiversity were investigated in marine sediments adjacent to the Okinawan “Kaichu-Doro” Causeway, which was constructed 46 years ago to connect a group of four islands (Henza-jima, Miyagi-jima, Ikei-jima, Hamahiga-jima to the Okinawan main island. This causeway was not built on pilings, but by land reclamation; hence, it now acts as a long, thin peninsula. The construction of this causeway was previously shown to have influenced the surrounding marine ecosystem, causing ecosystem fragmentation and loss of water circulation. In this study, we collected sediment cores (n = 10 from five paired sites in 1 m water depths. Each pair of sites consisted of one site each on the immediate north and south sides of the causeway. Originally the members of each pair were much closer to each other (<150 m than to other pairs, but now the members of each pair are isolated by the causeway. Each core was 60–80 cm long and was divided into 15-cm layers. We examined the vertical diversity of microbial communities and chemical compounds to determine the correlation between chemodiversity and microbial communities among marine sediment cores and layers. Principal coordinate analyses (PCoA of detected compounds and of bacterial and archaeal operational taxonomic units (OTUs revealed that the north and south sides of the causeway are relatively isolated, with each side having unique microbial OTUs. Additionally, some bacterial families (e.g., Acidaminobacteraceae, Rhizobiaceae, and Xanthomonadaceae were found only on the south side of Kaichu-Doro. Interestingly, we found that the relative abundance of OTUs for some microbial families increased from top to bottom, but this was reversed in some other families. We conclude that the causeway has altered microbial community composition and metabolite profiles in marine sediments.

  7. Diversity of Microbial Communities and Quantitative Chemodiversity in Layers of Marine Sediment Cores from a Causeway (Kaichu-Doro) in Okinawa Island, Japan.

    Science.gov (United States)

    Soliman, Taha; Reimer, James D; Yang, Sung-Yin; Villar-Briones, Alejandro; Roy, Michael C; Jenke-Kodama, Holger

    2017-01-01

    Microbial community diversity and chemodiversity were investigated in marine sediments adjacent to the Okinawan "Kaichu-Doro" Causeway, which was constructed 46 years ago to connect a group of four islands (Henza-jima, Miyagi-jima, Ikei-jima, Hamahiga-jima) to the Okinawan main island. This causeway was not built on pilings, but by land reclamation; hence, it now acts as a long, thin peninsula. The construction of this causeway was previously shown to have influenced the surrounding marine ecosystem, causing ecosystem fragmentation and loss of water circulation. In this study, we collected sediment cores ( n = 10) from five paired sites in 1 m water depths. Each pair of sites consisted of one site each on the immediate north and south sides of the causeway. Originally the members of each pair were much closer to each other (microbial communities and chemical compounds to determine the correlation between chemodiversity and microbial communities among marine sediment cores and layers. Principal coordinate analyses (PCoA) of detected compounds and of bacterial and archaeal operational taxonomic units (OTUs) revealed that the north and south sides of the causeway are relatively isolated, with each side having unique microbial OTUs. Additionally, some bacterial families (e.g., Acidaminobacteraceae, Rhizobiaceae, and Xanthomonadaceae) were found only on the south side of Kaichu-Doro. Interestingly, we found that the relative abundance of OTUs for some microbial families increased from top to bottom, but this was reversed in some other families. We conclude that the causeway has altered microbial community composition and metabolite profiles in marine sediments.

  8. The Multiplier Effect of the Gandoriah Beach Marine Tourism to the Coastal Community of Kelurahan Pasir, Central Pariaman District, Pariaman City West Sumatra Province

    OpenAIRE

    Mazidah, Nurnaini; Nugroho, Firman; Bathara, Lamun

    2016-01-01

    This research was conducted on March 25, 2016 until 11 April 2016 which is placed in Gandoriah Beach, Kelurahan Pasir, Central Pariaman District, Pariaman City West Sumatra Province. This study aims to identify economic activities and socio-cultural as the impact of the presence of marine tourism and determine the impact of tourism activities on the beach Gandoriah to the economy of coastal communities. The method used in this research is survey method. There are 64 respondents, that consist ...

  9. Irradiance optimization of outdoor microalgal cultures using solar tracked photobioreactors.

    Science.gov (United States)

    Hindersin, Stefan; Leupold, Marco; Kerner, Martin; Hanelt, Dieter

    2013-03-01

    Photosynthetic activity and temperature regulation of microalgal cultures (Chlorella vulgaris and Scenedesmus obliquus) under different irradiances controlled by a solar tracker and different cell densities were studied in outdoor flat panel photobioreactors. An automated process control unit regulated light and temperature as well as pH value and nutrient concentration in the culture medium. CO2 was supplied using flue gas from an attached combined block heat and power station. Photosynthetic activity was determined by pulse amplitude modulation fluorometry. Compared to the horizontal irradiance of 55 mol photons m(-2) d(-1) on a clear day, the solar tracked photobioreactors enabled a decrease and increase in the overall light absorption from 19 mol photons m(-2) d(-1) (by rotation out of direct irradiance) to 79 mol photons m(-2) d(-1) (following the position of the sun). At biomass concentrations below 1.1 g cell dry weight (CDW) L(-1), photoinhibition of about 35 % occurred at irradiances of ≥1,000 μmol photons m(-2) s(-1) photosynthetic active radiation (PAR). Using solar tracked photobioreactors, photoinhibition can be reduced and at optimum biomass concentration (≥2.3 g CDW L(-1)), the culture was irradiated up to 2,000 μmol photons m(-2) s(-1) to overcome light limitation with biomass yields of 0.7 g CDW mol photons(-1) and high photosynthetic activities indicated by an effective quantum yield of 0.68 and a maximum quantum yield of 0.80 (F v/F m). Overheating due to high irradiance was avoided by turning the PBR out of the sun or using a cooling system, which maintained the temperature close to the species-specific temperature optima.

  10. Microalgal biomass production pathways: evaluation of life cycle environmental impacts.

    Science.gov (United States)

    Zaimes, George G; Khanna, Vikas

    2013-06-20

    Microalgae are touted as an attractive alternative to traditional forms of biomass for biofuel production, due to high productivity, ability to be cultivated on marginal lands, and potential to utilize carbon dioxide (CO2) from industrial flue gas. This work examines the fossil energy return on investment (EROIfossil), greenhouse gas (GHG) emissions, and direct Water Demands (WD) of producing dried algal biomass through the cultivation of microalgae in Open Raceway Ponds (ORP) for 21 geographic locations in the contiguous United States (U.S.). For each location, comprehensive life cycle assessment (LCA) is performed for multiple microalgal biomass production pathways, consisting of a combination of cultivation and harvesting options. Results indicate that the EROIfossil for microalgae biomass vary from 0.38 to 1.08 with life cycle GHG emissions of -46.2 to 48.9 (g CO2 eq/MJ-biomass) and direct WDs of 20.8 to 38.8 (Liters/MJ-biomass) over the range of scenarios analyzed. Further anaylsis reveals that the EROIfossil for production pathways is relatively location invariant, and that algae's life cycle energy balance and GHG impacts are highly dependent on cultivation and harvesting parameters. Contrarily, algae's direct water demands were found to be highly sensitive to geographic location, and thus may be a constraining factor in sustainable algal-derived biofuel production. Additionally, scenarios with promising EROIfossil and GHG emissions profiles are plagued with high technological uncertainty. Given the high variability in microalgae's energy and environmental performance, careful evaluation of the algae-to-fuel supply chain is necessary to ensure the long-term sustainability of emerging algal biofuel systems. Alternative production scenarios and technologies may have the potential to reduce the critical demands of biomass production, and should be considered to make algae a viable and more efficient biofuel alternative.

  11. Microalgal CO2 sequestering – Modeling microalgae production costs

    International Nuclear Information System (INIS)

    Bilanovic, Dragoljub; Holland, Mark; Armon, Robert

    2012-01-01

    Highlights: ► Microalgae production costs were modeled as a function of specific expenses. ► The effects of uncontrollable expenses/factors were incorporated into the model. ► Modeled microalgae production costs were in the range $102–1503 t −1 ha −1 y −1 . - Abstract: Microalgae CO 2 sequestering facilities might become an industrial reality if microalgae biomass could be produced at cost below $500.00 t −1 . We develop a model for estimation of total production costs of microalgae as a function of known production-specific expenses, and incorporate into the model the effects of uncontrollable factors which affect known production-specific expenses. Random fluctuations were intentionally incorporated into the model, consequently into generated cost/technology scenarios, because each and every logically interconnected equipment/operation that is used in design/construction/operation/maintenance of a production process is inevitably subject to random cost/price fluctuations which can neither be eliminated nor a priori controlled. A total of 152 costs/technology scenarios were evaluated to find 44 scenarios in which predicted total production costs of microalgae (PTPCM) was in the range $200–500 t −1 ha −1 y −1 . An additional 24 scenarios were found with PTCPM in the range of $102–200 t −1 ha −1 y −1 . These findings suggest that microalgae CO 2 sequestering and the production of commercial compounds from microalgal biomass can be economically viable venture even today when microalgae production technology is still far from its optimum.

  12. Global analysis of gene expression dynamics within the marine microbial community during the VAHINE mesocosm experiment in the southwest Pacific

    Science.gov (United States)

    Pfreundt, Ulrike; Spungin, Dina; Bonnet, Sophie; Berman-Frank, Ilana; Hess, Wolfgang R.

    2016-07-01

    Microbial gene expression was followed for 23 days within a mesocosm (M1) isolating 50 m3 of seawater and in the surrounding waters in the Nouméa lagoon, New Caledonia, in the southwest Pacific as part of the VAriability of vertical and tropHIc transfer of diazotroph derived N in the south wEst Pacific (VAHINE) experiment. The aim of VAHINE was to examine the fate of diazotroph-derived nitrogen (DDN) in a low-nutrient, low-chlorophyll ecosystem. On day 4 of the experiment, the mesocosm was fertilized with phosphate. In the lagoon, gene expression was dominated by the cyanobacterium Synechococcus, closely followed by Alphaproteobacteria. In contrast, drastic changes in the microbial community composition and transcriptional activity were triggered within the mesocosm within the first 4 days, with transcription bursts from different heterotrophic bacteria in rapid succession. The microbial composition and activity of the surrounding lagoon ecosystem appeared more stable, although following similar temporal trends as in M1. We detected significant gene expression from Chromerida in M1, as well as the Nouméa lagoon, suggesting these photoautotrophic alveolates were present in substantial numbers in the open water. Other groups contributing substantially to the metatranscriptome were affiliated with marine Euryarchaeota Candidatus Thalassoarchaea (inside and outside) and Myoviridae bacteriophages likely infecting Synechococcus, specifically inside M1. High transcript abundances for ammonium transporters and glutamine synthetase in many different taxa (e.g., Pelagibacteraceae, Synechococcus, Prochlorococcus, and Rhodobacteraceae) was consistent with the known preference of most bacteria for this nitrogen source. In contrast, Alteromonadaceae highly expressed urease genes; Rhodobacteraceae and Prochlorococcus showed some urease expression, too. Nitrate reductase transcripts were detected on day 10 very prominently in Synechococcus and in Halomonadaceae. Alkaline

  13. Harvesting Microalgal Biomass grown in Anaerobic Sewage Treatment Effluent by the Coagulation-Flocculation Method: Effect of pH

    Directory of Open Access Journals (Sweden)

    Servio Tulio Cassini

    2017-03-01

    Full Text Available ABSTRACT Harvesting is a critical step in microalgal biomass production process for many reasons. Among the existing techniques available for harvesting and dewatering microalgal biomass, recovery from aqueous medium by coagulation-flocculation has been the most economically viable process, althoughit is highly dependent on pH. This study aims to assess alternative coagulants compared to the standard coagulant aluminum sulfate for microalgal biomass recovery from anaerobic effluent of domestic sewage treatment. The effluent quality was also analyzed after biomass recovery. Coagulants represented by modified tannin, cationic starch and aluminum sulfate recovered more than 90% of algae biomass, at concentrations greater than 80 mg/L, in the pH range 7-10. Cationic starch promoted higher microalgal biomass recovery with a wider pH range. Powdered seeds of Moringa oleifera and Hibiscus esculentus(okra gum promoted biomass removal of 50%, only in the acidic range of pH. After sedimentation of the microalgal biomass, the effluents showed a removal of >80% for phosphorus and nitrogen values and >50% for BOD and COD when using aluminum sulfate, cationic starch and modified tannin as coagulants. Natural organic coagulants in a wide pH range can replace aluminum sulfate, a reference coagulant in microalgal biomass recovery, without decreasing microalgal biomass harvesting efficiency and the quality of the final effluent.

  14. Isolation and Selection of Microalgal Strains from Natural Water Sources in Viet Nam with Potential for Edible Oil Production.

    Science.gov (United States)

    Thao, Tran Yen; Linh, Dinh Thi Nhat; Si, Vo Chi; Carter, Taylor W; Hill, Russell T

    2017-06-23

    Industrial vegetable oil production in Viet Nam depends on oil seeds and crude plant oils that are currently more than 90% imported. As the first step in investigating the feasibility of using microalgae to provide Viet Nam with a domestic source of oil for food and edible oil industries, fifty lipid-producing microalgae were isolated and characterized. The microalgae were isolated from water sources ranging from freshwater to brackish and marine waters from a wide geographic distribution in Viet Nam. Initial analyses showed that 20 of the 50 strains had good growth rates, produced high biomass and had high lipid content, ranging up to 50% of dry weight biomass. 18S rRNA gene sequence analyses of the 50 strains showed a great diversity in this assemblage of microalgae, comprising at least 38 species and representatives of 25 genera : Chlamydomonas , Poterioochromonas , Scenedesmus , Desmodesmus , Chlorella , Bracteacoccus , Monoraphidium , Selenastrum , Acutodesmus , Mychonastes , Ankistrodesmus , Kirchneriella , Raphidocelis , Dictyosphaerium , Coelastrella , Schizochlamydella , Oocystidium , Nannochloris , Auxenochlorella , Chlorosarcinopsis , Stichococcus , Picochlorum , Prasinoderma , Chlorococcum , and Marvania. Some of the species are closely related to well-known lipid producers such as Chlorella sorokiniana , but some other strains are not closely related to the strains found in public sequence databases and likely represent new species. Analysis of oil quality showed that fatty acid profiles of the microalgal strains were very diverse and strain-dependent. Fatty acids in the microalgal oils comprised saturated fatty acids (SFAs), poly-unsaturated fatty acids (PUFAs), and mono-unsaturated fatty acids (MUFAs). The main SFA was palmitic acid. MUFAs and PUFAs were dominated by oleic acid, and linoleic and linolenic acids, respectively. Some strains were especially rich in the essential fatty acid α-linolenic acid (ALA), which comprised more than 20% of the

  15. Understanding the scale of Marine protection in Hawai'i: from community-based management to the remote Northwestern Hawaiian Islands.

    Science.gov (United States)

    Friedlander, Alan M; Stamoulis, Kostantinos A; Kittinger, John N; Drazen, Jeffrey C; Tissot, Brian N

    2014-01-01

    Ancient Hawaiians developed a sophisticated natural resource management system that included various forms of spatial management. Today there exists in Hawai'i a variety of spatial marine management strategies along a range of scales, with varying degrees of effectiveness. State-managed no-take areas make up less than 0.4% of nearshore waters, resulting in limited ecological and social benefits. There is increasing interest among communities and coastal stakeholders in integrating aspects of customary Hawaiian knowledge into contemporary co-management. A network of no-take reserves for aquarium fish on Hawai'i Island is a stakeholder-driven, adaptive management strategy that has been successful in achieving ecological objectives and economic benefits. A network of large-scale no-take areas for deepwater (100-400m) bottomfishes suffered from a lack of adequate data during their initiation; however, better technology, more ecological data, and stakeholder input have resulted in improvements and the ecological benefits are becoming clear. Finally, the Papahānaumokuākea Marine National Monument (PMNM) is currently the single largest conservation area in the United States, and one of the largest in the world. It is considered an unqualified success and is managed under a new model of collaborative governance. These case studies allow an examination of the effects of scale on spatial marine management in Hawai'i and beyond that illustrate the advantages and shortcomings of different management strategies. Ultimately a marine spatial planning framework should be applied that incorporates existing marine managed areas to create a holistic, regional, multi-use zoning plan engaging stakeholders at all levels in order to maximize resilience of ecosystems and communities.

  16. Nitrosomonas Nm143-like ammonia oxidizers and Nitrospira marina -like nitrite oxidizers dominate the nitrifier community in a marine aquaculture biofilm

    DEFF Research Database (Denmark)

    Foesel, Bärbel U.; Gieseke, Armin; Schwermer, Carsten

    2008-01-01

    Zero-discharge marine aquaculture systems are an environmentally friendly alternative to conventional aquaculture. In these systems, water is purified and recycled via microbial biofilters. Here, quantitative data on nitrifier community structure of a trickling filter biofilm associated with a re......Zero-discharge marine aquaculture systems are an environmentally friendly alternative to conventional aquaculture. In these systems, water is purified and recycled via microbial biofilters. Here, quantitative data on nitrifier community structure of a trickling filter biofilm associated...

  17. Scenario Analysis of Nutrient Removal from Municipal Wastewater by Microalgal Biofilms

    NARCIS (Netherlands)

    Boelee, N.C.; Temmink, H.; Janssen, M.; Buisman, C.J.N.; Wijffels, R.H.

    2012-01-01

    Microalgae can be used for the treatment of municipal wastewater. The application of microalgal biofilms in wastewater treatment systems seems attractive, being able to remove nitrogen, phosphorus and COD from wastewater at a short hydraulic retention time. This study therefore investigates the area

  18. Similarity microalgal epiphyte composition on seagrass of Enhalus acoroides and Thalasia hemprichii from different waters

    Science.gov (United States)

    Hartati, R.; Zainuri, M.; Ambariyanto, A.; Widianingsih; Trianto, A.; Mahendrajaya, R. T.

    2018-03-01

    The epiphytes are all autotrophic organisms that are permanently attached to rhizomes, roots, and leaves of seagrasses. The epiphyte is an important primary producer for the seagrass ecosystem and contributes significantly to the food chain. This study aims to identify the composition of microepiphyte algae on Enhalus acoroides and Thalassia hemprichii and their similarity levels of both compositions. The 20 leaves samples of E. acoroides and T. hemprichii were observed. The epiphytic microalgae which found on the surface of the seagrass leaves were scrapped, collected in a bottle sample, and fixed with 70 % alcohol and identified into genera. The relation of epiphytic microalgal genera to the location and species of seagrass was analyzed using similarity analysis. The Chrysophyta, Cyanophyta, and Chlorophyta epiphytic microalgal were found. There were similarity variations of the microalgal epiphyte in seagrass of E. acoroides and T. hemprichii and seagrass habitat sites. Morphology and seagrass life affects the abundance and diversity of the epiphytic microalgal attached to the seagrass and it may be associated with the epiphytic lifetime in the seagrass.

  19. Benthic microalgal production in the Arctic: Applied methods and status of the current database

    DEFF Research Database (Denmark)

    Glud, Ronnie Nøhr; Woelfel, Jana; Karsten, Ulf

    2009-01-01

    The current database on benthic microalgal production in Arctic waters comprises 10 peer-reviewed and three unpublished studies. Here, we compile and discuss these datasets, along with the applied measurement approaches used. The latter is essential for robust comparative analysis and to clarify ...

  20. Advances in photobioreactors for intensive microalgal production: configurations, operating strategies and applications

    NARCIS (Netherlands)

    Olivieri, G.; Salatino, P.; Marzocchella, A.

    2014-01-01

    Over the past ten years a great deal of literature has focused on the biotechnological potential of microalgal commercial applications, mainly in the field of biofuel production. However, the biofuel production is not yet competitive, mainly due to the incidence of the photobioreactor technology on

  1. Phosphorus removal using a microalgal biofilm in a new biofilm photobioreactor for tertiary wastewater treatment

    Czech Academy of Sciences Publication Activity Database

    Sukačová, Kateřina; Trtílek, M.; Rataj, Tomáš

    2015-01-01

    Roč. 75, mar (2015), s. 55-63 ISSN 0043-1354 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : microalgal biofilm * phosphorus removal * wastewater treatment Subject RIV: EH - Ecology, Behaviour Impact factor: 5.991, year: 2015

  2. Phylogenetic analysis of the fecal microbial community in herbivorous land and marine iguanas of the Galápagos Islands using 16S rRNA-based pyrosequencing.

    Science.gov (United States)

    Hong, Pei-Ying; Wheeler, Emily; Cann, Isaac K O; Mackie, Roderick I

    2011-09-01

    Herbivorous reptiles depend on complex gut microbial communities to effectively degrade dietary polysaccharides. The composition of these fermentative communities may vary based on dietary differences. To explore the role of diet in shaping gut microbial communities, we evaluated the fecal samples from two related host species--the algae-consuming marine iguana (Amblyrhynchus cristatus) and land iguanas (LI) (genus Conolophus) that consume terrestrial vegetation. Marine and LI fecal samples were collected from different islands in the Galápagos archipelago. High-throughput 16S rRNA-based pyrosequencing was used to provide a comparative analysis of fecal microbial diversity. At the phylum level, the fecal microbial community in iguanas was predominated by Firmicutes (69.5±7.9%) and Bacteroidetes (6.2±2.8%), as well as unclassified Bacteria (20.6±8.6%), suggesting that a large portion of iguana fecal microbiota is novel and could be involved in currently unknown functions. Host species differed in the abundance of specific bacterial groups. Bacteroides spp., Lachnospiraceae and Clostridiaceae were significantly more abundant in the marine iguanas (MI) (P-value>1E-9). In contrast, Ruminococcaceae were present at >5-fold higher abundance in the LI than MI (P-value>6E-14). Archaea were only detected in the LI. The number of operational taxonomic units (OTUs) in the LI (356-896 OTUs) was >2-fold higher than in the MI (112-567 OTUs), and this increase in OTU diversity could be related to the complexity of the resident bacterial population and their gene repertoire required to breakdown the recalcitrant polysaccharides prevalent in terrestrial plants. Our findings suggest that dietary differences contribute to gut microbial community differentiation in herbivorous lizards. Most importantly, this study provides a better understanding of the microbial diversity in the iguana gut; therefore facilitating future efforts to discover novel bacterial-associated enzymes that

  3. A twisted tale - how biocorrosion communities yield new insight on the distribution of marine iron-oxidizing bacteria

    Science.gov (United States)

    McBeth, J. M.; Emerson, D.

    2011-12-01

    Microbiologically influenced corrosion (MIC) of mild steel is a complex process involving biogeochemical interactions between bacteria, steel surfaces, and biogenic and abiotically produced minerals. The role of neutrophilic iron-oxidizing bacteria (FeOB) in this process is poorly understood, and surprisingly, little is known about the microbial ecology of corroding steel in marine environments. Based on previous work (McBeth et al 2011), we hypothesized that coastal sediments act as reservoirs for marine FeOB of the candidatus class 'Zetaproteobacteria', and that these bacteria will colonize and become numerically abundant on steel surfaces. To test this, mild steel coupons were incubated in a salt marsh and sampled over 40 days in summer 2010. DNA extracted from the steel surfaces was analyzed for overall bacterial diversity by pyrosequencing of the V4 variable region of the 16S rRNA gene, and relevant communities were quantified using qPCR. The qPCR analyses were done using 16S primers specific to prokaryotes (Takai & Horikoshi 2000) and Zetaproteobacteria (Kato et al 2009), and a dsrA gene specific primer (Ben-Dov et al 2007) to assess the population of sulfate-reducing bacteria (SRB). Pyrosequencing data analyses showed Zetaproteobacteria were present on steel samples throughout the incubations and were also present in adjacent sediments; however, the diversity of Zetaproteobacteria was lower on the steel in comparison with sediments, indicating specific populations were enriched on the steel coupons. Iron oxyhydroxide stalk biosignatures were observed on the steel and in enrichment cultures, evidence that the Zetaproteobacteria identified using molecular techniques were likely FeOB. Relatives of the H2-oxidizing genus Hydrogenophaga and members of the family Rhodobacterales were also identified as important members of the biocorrosion community and were present both on steel and in sediments. The diversity of these organisms on steel surfaces increased with

  4. Consolidated bioprocessing of microalgal biomass to carboxylates by a mixed culture of cow rumen bacteria using anaerobic sequencing batch reactor (ASBR).

    Science.gov (United States)

    Zhao, Baisuo; Liu, Jie; Frear, Craig; Holtzapple, Mark; Chen, Shulin

    2016-12-01

    This study employed mixed-culture consolidated bioprocessing (CBP) to digest microalgal biomass in an anaerobic sequencing batch reactor (ASBR). The primary objectives are to evaluate the impact of hydraulic residence time (HRT) on the productivity of carboxylic acids and to characterize the bacterial community. HRT affects the production rate and patterns of carboxylic acids. For the 5-L laboratory-scale fermentation, a 12-day HRT was selected because it offered the highest productivity of carboxylic acids and it synthesized longer chains. The variability of the bacterial community increased with longer HRT (R 2 =0.85). In the 5-L laboratory-scale fermentor, the most common phyla were Firmicutes (58.3%), Bacteroidetes (27.4%), and Proteobacteria (11.9%). The dominant bacterial classes were Clostridia (29.8%), Bacteroidia (27.4%), Tissierella (26.2%), and Betaproteobacteria (8.9%). Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Rumen bacterial community evaluated by 454 pyrosequencing and terminal restriction fragment length polymorphism analyses in dairy sheep fed marine algae.

    Science.gov (United States)

    Castro-Carrera, T; Toral, P G; Frutos, P; McEwan, N R; Hervás, G; Abecia, L; Pinloche, E; Girdwood, S E; Belenguer, A

    2014-03-01

    Developing novel strategies to increase the content of bioactive unsaturated fatty acids (FA) in ruminant-derived products requires a deeper understanding of rumen biohydrogenation and bacteria involved in this process. Although high-throughput pyrosequencing may allow for a great coverage of bacterial diversity, it has hardly been used to investigate the microbiology of ruminal FA metabolism. In this experiment, 454 pyrosequencing and a molecular fingerprinting technique (terminal restriction fragment length polymorphism; T-RFLP) were used concurrently to assess the effect of diet supplementation with marine algae (MA) on the rumen bacterial community of dairy sheep. Eleven lactating ewes were divided in 2 lots and offered a total mixed ration based on alfalfa hay and concentrate (40:60), supplemented with 0 (control) or 8 (MA) g of MA/kg of dry matter. After 54 d on treatments, animals were slaughtered and samples of rumen content and fluid were collected separately for microbial analysis. Pyrosequencing yielded a greater coverage of bacterial diversity than T-RFLP and allowed the identification of low abundant populations. Conversely, both molecular approaches pointed to similar conclusions and showed that relevant changes due to MA addition were observed within the major ruminal phyla, namely Bacteroidetes, Firmicutes, and Proteobacteria. Decreases in the abundance of unclassified Bacteroidales, Porphyromonadaceae, and Ruminococcaceae and increases in as-yet uncultured species of the family Succinivibrionaceae, might be related to a potential role of these groups in different pathways of rumen FA metabolism. Diet supplementation with MA, however, had no effect on the relative abundance of Butyrivibrio and Pseudobutyrivibrio genera. In addition, results from both 454 pyrosequencing and T-RFLP indicate that the effect of MA was rather consistent in rumen content or fluid samples, despite inherent differences between these fractions in their bacterial composition

  6. Seawater quality and microbial communities at a desalination plant marine outfall. A field study at the Israeli Mediterranean coast.

    Science.gov (United States)

    Drami, Dror; Yacobi, Yosef Z; Stambler, Noga; Kress, Nurit

    2011-11-01

    Global desalination quadrupled in the last 15 years and the relative importance of seawater desalination by reverse osmosis (SWRO) increased as well. While the technological aspects of SWRO plants are extensively described, studies on the environmental impact of brine discharge are lacking, in particular in situ marine environmental studies. The Ashqelon SWRO plant (333,000 m(3) d(-1) freshwater) discharges brine and backwash of the pre-treatment filters (containing ferric hydroxide coagulant) at the seashore, next to the cooling waters of a power plant. At the time of this study brine and cooling waters were discharged continuously and the backwash discharge was pulsed, with a frequency dependent on water quality at the intake. The effects of the discharges on water quality and neritic microbial community were identified, quantified and attributed to the different discharges. The mixed brine-cooling waters discharge increased salinity and temperature at the outfall, were positively buoyant, and dispersed at the surface up to 1340 m south of the outfall. Nutrient concentrations were higher at the outfall while phytoplankton densities were lower. Chlorophyll-a and picophytoplankton cell numbers were negatively correlated with salinity, but more significantly with temperature probably as a result of thermal pollution. The discharge of the pulsed backwash increased turbidity, suspended particulate matter and particulate iron and decreased phytoplankton growth efficiency at the outfall, effects that declined with distance from the outfall. The discharges clearly reduced primary production but we could not attribute the effect to a specific component of the discharge. Bacterial production was also affected but differently in the three surveys. The combined and possible synergistic effects of SWRO desalination along the Israeli shoreline should be taken into account when the three existing plants and additional ones are expected to produce 2 Mm(3) d(-1) freshwater by

  7. Novel Concept for LSS Based on Advanced Microalgal Biotechnologies

    Science.gov (United States)

    Brown, I.; Jones, J. A.; Bayless, D.; Karakis, S.; Karpov, L.; McKay, D. S.

    2006-01-01

    One of the key issues for successful human space exploration is biomedical life support in hostile space and planetary environments that otherwise cannot sustain life. Bioregenerative life support systems (LSS) are one of the options for atmospheric regeneration. To date, no bioregenerative LSS has shown capability for 100% air regeneration. Nor have these LSS been robust enough to simultaneously provide a regenerable complete food source. In contrast to microalgae, traditional plant approaches, e.g. wheat and lettuce, are lacking essential amino acids, vitamins, and micronutrients. Moreover, the rate of photosynthesis by microalgae significantly exceeds that of high plants. Nevertheless, the employment of microalgae in LSS technology was restricted, until recently, due to high water demands. Also the per person requirement of a 40L volume of microalgae in a photobioreactor, to provide daily O2 production, made an algae-based approach less attractive. By employing a vertically stacked membrane bioreactor, coupled with a solar tracker and photon-delivery system, a lightweight air revitalization system for space based applications, with minimal water requirements, can be developed. Our preliminary estimations suggest that a membrane bioreactor, 8m3 in volume, comprised of 80m2 (twenty 2m x 2m membranes, each spaced 10 cm apart), and a total of 70L of water could produce 2.7 kg of dried microalgal biomass that would supply the energy and essential amino acid requirements, as well as producing sufficient O2 for the daily needs of a 15 member crew. Research on the biochemical content of edible blue-green alga Spirulina (Arthrospira) platensis shows a wide spectrum of stable Spirulina mutants with an enhanced content of amino acids, -carotene, and phycobilliprotein c-phycocyanin. Feeding animals suffering from radiation-induced lesions, c-phycocyanin, extracted from strain 27G, led to a correction in the decrement of dehydrogenase activity and energy-rich phosphate

  8. Conserving biodiversity in a human-dominated world: degradation of marine sessile communities within a protected area with conflicting human uses.

    Directory of Open Access Journals (Sweden)

    Valeriano Parravicini

    Full Text Available Conservation research aims at understanding whether present protection schemes are adequate for the maintenance of ecosystems structure and function across time. We evaluated long-term variation in rocky reef communities by comparing sites surveyed in 1993 and again in 2008. This research took place in Tigullio Gulf, an emblematic case study where various conservation measures, including a marine protected area, have been implemented to manage multiple human uses. Contrary to our prediction that protection should have favored ecosystem stability, we found that communities subjected to conservation measures (especially within the marine protected area exhibited the greatest variation toward architectural complexity loss. Between 1993 and 2008, chronic anthropogenic pressures (especially organic load that had already altered unprotected sites in 1993 expanded their influence into protected areas. This expansion of human pressure likely explains our observed changes in the benthic communities. Our results suggest that adaptive ecosystem-based management (EBM, that is management taking into account human interactions, informed by continuous monitoring, is needed in order to attempt reversing the current trend towards less architecturally complex communities. Protected areas are not sufficient to stop ecosystem alteration by pressures coming from outside. Monitoring, and consequent management actions, should therefore extend to cover the relevant scales of those pressures.

  9. The bacterial community structure of hydrocarbon-polluted marine environments as the basis for the definition of an ecological index of hydrocarbon exposure.

    Science.gov (United States)

    Lozada, Mariana; Marcos, Magalí S; Commendatore, Marta G; Gil, Mónica N; Dionisi, Hebe M

    2014-09-17

    The aim of this study was to design a molecular biological tool, using information provided by amplicon pyrosequencing of 16S rRNA genes, that could be suitable for environmental assessment and bioremediation in marine ecosystems. We selected 63 bacterial genera that were previously linked to hydrocarbon biodegradation, representing a minimum sample of the bacterial guild associated with this process. We defined an ecological indicator (ecological index of hydrocarbon exposure, EIHE) using the relative abundance values of these genera obtained by pyrotag analysis. This index reflects the proportion of the bacterial community that is potentially capable of biodegrading hydrocarbons. When the bacterial community structures of intertidal sediments from two sites with different pollution histories were analyzed, 16 of the selected genera (25%) were significantly overrepresented with respect to the pristine site, in at least one of the samples from the polluted site. Although the relative abundances of individual genera associated with hydrocarbon biodegradation were generally low in samples from the polluted site, EIHE values were 4 times higher than those in the pristine sample, with at least 5% of the bacterial community in the sediments being represented by the selected genera. EIHE values were also calculated in other oil-exposed marine sediments as well as in seawater using public datasets from experimental systems and field studies. In all cases, the EIHE was significantly higher in oiled than in unpolluted samples, suggesting that this tool could be used as an estimator of the hydrocarbon-degrading potential of microbial communities.

  10. Biogeographic Characterization of Fish Communities within the Flower Garden Banks National Marine Sanctuary (2006 - 2007) (NODC Accession 0118358)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The overarching goal of this collaboration was to provide the Flower Garden Banks National Marine Sanctuary (FGBNMS) staff with information on biogeographic patterns...

  11. Reef-fish larval dispersal patterns validate no-take marine reserve network connectivity that links human communities

    KAUST Repository

    Abesamis, Rene A.; Saenz-Agudelo, Pablo; Berumen, Michael L.; Bode, Michael; Jadloc, Claro Renato L.; Solera, Leilani A.; Villanoy, Cesar L.; Bernardo, Lawrence Patrick C.; Alcala, Angel C.; Russ, Garry R.

    2017-01-01

    Networks of no-take marine reserves (NTMRs) are a widely advocated strategy for managing coral reefs. However, uncertainty about the strength of population connectivity between individual reefs and NTMRs through larval dispersal remains a major

  12. An Aqueous Extract of Marine Microalgae Exhibits Antimetastatic Activity through Preferential Killing of Suspended Cancer Cells and Anticolony Forming Activity

    Science.gov (United States)

    Somasekharan, Syam Prakash; El-Naggar, Amal; Sorensen, Poul H.

    2016-01-01

    Research on marine natural products as potential anticancer agents is still limited. In the present study, an aqueous extract of a Canadian marine microalgal preparation was assessed for anticancer activities using various assays and cell lines of human cancers, including lung, prostate, stomach, breast, and pancreatic cancers, as well as an osteosarcoma. In vitro, the microalgal extract exhibited marked anticolony forming activity. In addition, it was more toxic, as indicated by increased apoptosis, to nonadherent cells (grown in suspension) than to adherent cells. In vivo, an antimetastatic effect of the extract was observed in NOD-SCID mice carrying subrenal capsule xenografts of PC3 prostate cancer cells. The results of the present study suggest that the antimetastatic effect of the aqueous microalgal extract is based on inhibition of colony forming ability of cancer cells and the preferential killing of suspended cancer cells. Further research aimed at identification of the molecular basis of the anticancer activities of the microalgal extract appears to be warranted. PMID:27656243

  13. An Aqueous Extract of Marine Microalgae Exhibits Antimetastatic Activity through Preferential Killing of Suspended Cancer Cells and Anticolony Forming Activity

    Directory of Open Access Journals (Sweden)

    Syam Prakash Somasekharan

    2016-01-01

    Full Text Available Research on marine natural products as potential anticancer agents is still limited. In the present study, an aqueous extract of a Canadian marine microalgal preparation was assessed for anticancer activities using various assays and cell lines of human cancers, including lung, prostate, stomach, breast, and pancreatic cancers, as well as an osteosarcoma. In vitro, the microalgal extract exhibited marked anticolony forming activity. In addition, it was more toxic, as indicated by increased apoptosis, to nonadherent cells (grown in suspension than to adherent cells. In vivo, an antimetastatic effect of the extract was observed in NOD-SCID mice carrying subrenal capsule xenografts of PC3 prostate cancer cells. The results of the present study suggest that the antimetastatic effect of the aqueous microalgal extract is based on inhibition of colony forming ability of cancer cells and the preferential killing of suspended cancer cells. Further research aimed at identification of the molecular basis of the anticancer activities of the microalgal extract appears to be warranted.

  14. Ultrasonic disintegration of microalgal biomass and consequent improvement of bioaccessibility/bioavailability in microbial fermentation.

    Science.gov (United States)

    Jeon, Byong-Hun; Choi, Jeong-A; Kim, Hyun-Chul; Hwang, Jae-Hoon; Abou-Shanab, Reda Ai; Dempsey, Brian A; Regan, John M; Kim, Jung Rae

    2013-01-01

    Microalgal biomass contains a high level of carbohydrates which can be biochemically converted to biofuels using state-of-the-art strategies that are almost always needed to employ a robust pretreatment on the biomass for enhanced energy production. In this study, we used an ultrasonic pretreatment to convert microalgal biomass (Scenedesmus obliquus YSW15) into feasible feedstock for microbial fermentation to produce ethanol and hydrogen. The effect of sonication condition was quantitatively evaluated with emphases on the characterization of carbohydrate components in microalgal suspension and on subsequent production of fermentative bioenergy. Scenedesmus obliquus YSW15 was isolated from the effluent of a municipal wastewater treatment plant. The sonication durations of 0, 10, 15, and 60 min were examined under different temperatures at a fixed frequency and acoustic power resulted in morphologically different states of microalgal biomass lysis. Fermentation was performed to evaluate the bioenergy production from the non-sonicated and sonicated algal biomasses after pretreatment stage under both mesophilic (35°C) and thermophilic (55°C) conditions. A 15 min sonication treatment significantly increased the concentration of dissolved carbohydrates (0.12 g g(-1)), which resulted in an increase of hydrogen/ethanol production through microbial fermentation. The bioconvertibility of microalgal biomass sonicated for 15 min or longer was comparable to starch as a control, indicating a high feasibility of using microalgae for fermentative bioenergy production. Increasing the sonication duration resulted in increases in both algal surface hydrophilicity and electrostatic repulsion among algal debris dispersed in aqueous solution. Scanning electron microscope images supported that ruptured algal cell allowed fermentative bacteria to access the inner space of the cell, evidencing an enhanced bioaccessibility. Sonication for 15 min was the best for fermentative

  15. Re-Structuring of Marine Communities Exposed to Environmental Change: A Global Study on the Interactive Effects of Species and Functional Richness

    Science.gov (United States)

    Wahl, Martin; Link, Heike; Alexandridis, Nicolaos; Thomason, Jeremy C.; Cifuentes, Mauricio; Costello, Mark J.; da Gama, Bernardo A. P.; Hillock, Kristina; Hobday, Alistair J.; Kaufmann, Manfred J.; Keller, Stefanie; Kraufvelin, Patrik; Krüger, Ina; Lauterbach, Lars; Antunes, Bruno L.; Molis, Markus; Nakaoka, Masahiro; Nyström, Julia; bin Radzi, Zulkamal; Stockhausen, Björn; Thiel, Martin; Vance, Thomas; Weseloh, Annika; Whittle, Mark; Wiesmann, Lisa; Wunderer, Laura; Yamakita, Takehisa; Lenz, Mark

    2011-01-01

    Species richness is the most commonly used but controversial biodiversity metric in studies on aspects of community stability such as structural composition or productivity. The apparent ambiguity of theoretical and experimental findings may in part be due to experimental shortcomings and/or heterogeneity of scales and methods in earlier studies. This has led to an urgent call for improved and more realistic experiments. In a series of experiments replicated at a global scale we translocated several hundred marine hard bottom communities to new environments simulating a rapid but moderate environmental change. Subsequently, we measured their rate of compositional change (re-structuring) which in the great majority of cases represented a compositional convergence towards local communities. Re-structuring is driven by mortality of community components (original species) and establishment of new species in the changed environmental context. The rate of this re-structuring was then related to various system properties. We show that availability of free substratum relates negatively while taxon richness relates positively to structural persistence (i.e., no or slow re-structuring). Thus, when faced with environmental change, taxon-rich communities retain their original composition longer than taxon-poor communities. The effect of taxon richness, however, interacts with another aspect of diversity, functional richness. Indeed, taxon richness relates positively to persistence in functionally depauperate communities, but not in functionally diverse communities. The interaction between taxonomic and functional diversity with regard to the behaviour of communities exposed to environmental stress may help understand some of the seemingly contrasting findings of past research. PMID:21611170

  16. Assessment of Environmental Stresses for Enhanced Microalgal Biofuel Production – An Overview

    International Nuclear Information System (INIS)

    Cheng, Dan; He, Qingfang

    2014-01-01

    Microalgal biofuels are currently considered to be the most promising alternative to future renewable energy source. Microalgae have great potential to produce various biofuels, including biodiesel, bioethanol, biomethane, and biohydrogen. Cultivation of biofuel-producing microalgae demands favorable environmental conditions, such as suitable light, temperature, nutrients, salinity, and pH. However, these conditions are not always compatible with the conditions beneficial to biofuel production, because biofuel-related compounds (such as lipids and carbohydrates) tend to accumulate under environmental-stress conditions of light, temperature, nutrient, and salt. This paper presents a brief overview of the effects of environmental conditions on production of microalgal biomass and biofuel, with specific emphasis on how to utilize environmental stresses to improve biofuel productivity. The potential avenues of reaping the benefits of enhanced biofuel production by environmental stresses while maintaining high yields of biomass production have been discussed.

  17. Direct measurement and characterization of active photosynthesis zones inside biofuel producing and wastewater remediating microalgal biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, Hans C.; Kesaano, Maureen; Moll, Karen; Smith, Terence; Gerlach, Robin; Carlson, Ross; Miller, Charles D.; Peyton, Brent; Cooksey, Keith; Gardner, Robert D.; Sims, Ronald C.

    2014-03-01

    Abstract: Microalgal biofilm based technologies are of keen interest due to their high biomass concentrations and ability to utilize renewable resources, such as light and CO2. While photoautotrophic biofilms have long been used for wastewater remediation applications, biofuel production represents a relatively new and under-represented focus area. However, the direct measurement and characterization of fundamental parameters required for physiological analyses are challenging due to biofilm heterogeneity. This study evaluated oxygenic photosynthesis and biofuel precursor molecule production using a novel rotating algal biofilm reactor (RABR) operated at field- and laboratory-scales for wastewater remediation and biofuel production, respectively. Clear differences in oxygenic-photosynthesis, respiration and biofuel-precursor capacities were observed between the two systems and different conditions based on light and nitrogen availability. Nitrogen depletion was not found to have the same effect on lipid accumulation compared to prior planktonic studies. Physiological characterizations of these microalgal biofilms identify potential areas for future process optimization.

  18. Assessment of environmental stresses for enhanced microalgal biofuel production-an overview

    Directory of Open Access Journals (Sweden)

    Dan eCheng

    2014-07-01

    Full Text Available Microalgal biofuels are currently considered to be the most promising alternative to future renewable energy source. Microalgae have great potential to produce various biofuels, including biodiesel, bioethanol, biomethane, and biohydrogen. Cultivation of biofuel-producing microalgae demands favorable environmental conditions, such as suitable light, temperature, nutrients, salinity, and pH. However, these conditions are not always compatible with the conditions beneficial to biofuel production, because biofuel-related compounds (such as lipids and carbohydrates tend to accumulate under environmental-stress conditions of light, temperature, nutrient, and salt. This paper presents a brief overview of the effects of environmental conditions on production of microalgal biomass and biofuel, with specific emphasis on how to utilize environmental stresses to improve biofuel productivity. The potential avenues of reaping the benefits of enhanced biofuel production by environmental stresses while maintaining high yields of biomass production have been discussed.

  19. Utilization of Microalgal Biofractions for Bioethanol, Higher Alcohols, and Biodiesel Production: A Review

    Directory of Open Access Journals (Sweden)

    Marwa M. El-Dalatony

    2017-12-01

    Full Text Available Biomass is a crucial energy resource used for the generation of electricity and transportation fuels. Microalgae exhibit a high content of biocomponents which makes them a potential feedstock for the generation of ecofriendly biofuels. Biofuels derived from microalgae are suitable carbon-neutral replacements for petroleum. Fermentation is the major process for metabolic conversion of microalgal biocompounds into biofuels such as bioethanol and higher alcohols. In this review, we explored the use of all three major biocomponents of microalgal biomass including carbohydrates, proteins, and lipids for maximum biofuel generation. Application of several pretreatment methods for enhancement the bioavailability of substrates (simple sugar, amino acid, and fatty acid was discussed. This review goes one step further to discuss how to direct these biocomponents for the generation of various biofuels (bioethanol, higher alcohol, and biodiesel through fermentation and transesterification processes. Such an approach would result in the maximum utilization of biomasses for economically feasible biofuel production.

  20. Assessment of Environmental Stresses for Enhanced Microalgal Biofuel Production – An Overview

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Dan, E-mail: dxcheng@ualr.edu; He, Qingfang, E-mail: dxcheng@ualr.edu [Department of Applied Science, University of Arkansas at Little Rock, Little Rock, AR (United States)

    2014-07-07

    Microalgal biofuels are currently considered to be the most promising alternative to future renewable energy source. Microalgae have great potential to produce various biofuels, including biodiesel, bioethanol, biomethane, and biohydrogen. Cultivation of biofuel-producing microalgae demands favorable environmental conditions, such as suitable light, temperature, nutrients, salinity, and pH. However, these conditions are not always compatible with the conditions beneficial to biofuel production, because biofuel-related compounds (such as lipids and carbohydrates) tend to accumulate under environmental-stress conditions of light, temperature, nutrient, and salt. This paper presents a brief overview of the effects of environmental conditions on production of microalgal biomass and biofuel, with specific emphasis on how to utilize environmental stresses to improve biofuel productivity. The potential avenues of reaping the benefits of enhanced biofuel production by environmental stresses while maintaining high yields of biomass production have been discussed.

  1. Aerobic treatment of swine manure to enhance anaerobic digestion and microalgal cultivation.

    Science.gov (United States)

    Bekoe, Dominic; Wang, Lijun; Zhang, Bo; Scott Todd, Matthew; Shahbazi, Abolghasem

    2018-02-01

    Aerobic treatment of swine manure was coupled with anaerobic digestion and microalgal cultivation. A 14-day aerobic treatment reduced the total solid content of swine manure by >15%. Ammonia and carbon dioxide were stripped by the air supplied, and this off-gas was further used to aerate the culture of Chlorella vulgaris. The microalgal growth rates in Bristol medium and the wastewater with the off-gas increased from 0.08 to 0.22 g/L/d and from 0.15 to 0.24 g/L/d, respectively. Meanwhile, the aerobically treated swine manure showed a higher methane yield during anaerobic digestion. The experimental results were used to establish a demonstration unit consisting of a 100 L composter, a 200 L anaerobic digester, a 60 L tubular photobioreactor, and a 300 L micro-open raceway pond.

  2. Temporal changes in the diazotrophic bacterial communities associated with Caribbean sponges Ircinia stroblina and Mycale laxissima

    Directory of Open Access Journals (Sweden)

    Fan eZhang

    2014-10-01

    Full Text Available Sponges that harbor microalgal or cyanobacterial symbionts may benefit from photosynthetically derived carbohydrates, which are rich in carbon but devoid of nitrogen, and may therefore encounter nitrogen limitation. Diazotrophic communities associated with two Caribbean sponges, Ircinia strobilina and Mycale laxissima were studied in a time series during which three individuals of each sponge were collected in four time points (5:00 AM, 12:00 noon, 5:00 PM, 10:00 PM. nifH genes were successfully amplified from the corresponding gDNA and cDNA pools and sequenced by high throughput 454 amplicon sequencing. In both sponges, over half the nifH transcripts were classified as from cyanobacteria and the remainder from heterotrophic bacteria. We found various groups of bacteria actively expressing the nifH gene during the entire day-night cycle, an indication that the nitrogen fixation potential was fully exploited by different nitrogen fixing bacteria groups associated with their hosts. This study showed for the first time the dynamic changes in the activity of the diazotrophic bacterial communities in marine sponges. Our study expands understanding of the diazotrophic groups that contribute to the fixed nitrogen pool in the benthic community. Sponge bacterial community-associated diazotrophy may have an important impact on the nitrogen biogeochemical cycle in the coral reef ecosystem.

  3. Temporal changes in the diazotrophic bacterial communities associated with Caribbean sponges Ircinia stroblina and Mycale laxissima.

    Science.gov (United States)

    Zhang, Fan; Vicente, Jan; Hill, Russell T

    2014-01-01

    Sponges that harbor microalgal or, cyanobacterial symbionts may benefit from photosynthetically derived carbohydrates, which are rich in carbon but devoid of nitrogen, and may therefore encounter nitrogen limitation. Diazotrophic communities associated with two Caribbean sponges, Ircinia strobilina and Mycale laxissima were studied in a time series during which three individuals of each sponge were collected in four time points (5:00 AM, 12:00 noon, 5:00 PM, 10:00 PM). nifH genes were successfully amplified from the corresponding gDNA and cDNA pools and sequenced by high throughput 454 amplicon sequencing. In both sponges, over half the nifH transcripts were classified as from cyanobacteria and the remainder from heterotrophic bacteria. We found various groups of bacteria actively expressing the nifH gene during the entire day-night cycle, an indication that the nitrogen fixation potential was fully exploited by different nitrogen fixing bacteria groups associated with their hosts. This study showed for the first time the dynamic changes in the activity of the diazotrophic bacterial communities in marine sponges. Our study expands understanding of the diazotrophic groups that contribute to the fixed nitrogen pool in the benthic community. Sponge bacterial community-associated diazotrophy may have an important impact on the nitrogen biogeochemical cycle in the coral reef ecosystem.

  4. Microalgal cultivation for value-added products: a critical enviro-economical assessment.

    Science.gov (United States)

    Kothari, Richa; Pandey, Arya; Ahmad, Shamshad; Kumar, Ashwani; Pathak, Vinayak V; Tyagi, V V

    2017-08-01

    The present review focuses on the cultivation of algal biomass for generating value-added products (VAP) and to assess their economic benefits and harmful environmental impact. Additionally, the impact of bioreactor designs on the yield of microalgal biomass for VAP is also considered. All these factors are discussed in relation to the impact of microalgae production on the bio-economy sector of commercial biotechnology.

  5. Production of Microalgal Lipids as Biodiesel Feedstock with Fixation of CO2 by Chlorella vulgaris

    OpenAIRE

    Qiao Hu; Sen-Xiang Zhang; Zhong-Hua Yang; Hao Huang; Rong Zeng

    2014-01-01

    The global warming and shortage of energy are two critical problems for human social development. CO2 mitigation and replacing conventional diesel with biodiesel are effective routes to reduce these problems. Production of microalgal lipids as biodiesel feedstock by a freshwater microalga, Chlorella vulgaris, with the ability to fixate CO2 is studied in this work. The results show that nitrogen deficiency, CO2 volume fraction and photoperiod are the key factors responsible for the lipid accum...

  6. Exploring the efficacy of wastewater-grown microalgal biomass as a biofertilizer for wheat.

    Science.gov (United States)

    Renuka, Nirmal; Prasanna, Radha; Sood, Anjuli; Ahluwalia, Amrik S; Bansal, Radhika; Babu, Santosh; Singh, Rajendra; Shivay, Yashbir S; Nain, Lata

    2016-04-01

    Microalgae possess the ability to grow and glean nutrients from wastewater; such wastewater-grown biomass can be used as a biofertilizer for crops. The present investigation was undertaken to evaluate two formulations (formulation with unicellular microalgae (MC1) and formulation with filamentous microalgae (MC2); T4 and T5, respectively), prepared using wastewater-grown microalgal biomass, as a biofertilizer (after mixing with vermiculite/compost as a carrier) in wheat crop (Triticum aestivum L. HD2967) under controlled conditions. The highest values of available nitrogen (N), phosphorus (P), and potassium (K) in soil and nitrogen-fixing potential were recorded in treatment T5 (75% N + full-dose PK + formulation with filamentous microalgae (MC2). Microbial biomass carbon was significantly enhanced by 31.8-67.0% in both the inoculated treatments over control (recommended dose of fertilizers), with highest values in T4 (75% N + full-dose PK + formulation with unicellular microalgae (MC1)). Both the microalgal formulations significantly increased the N, P, and K content of roots, shoots, and grains, and the highest total N content of 3.56% in grains was observed in treatment T5. At harvest stage, the treatments inoculated with microalgal formulations (T4 and T5) recorded a 7.4-33% increase in plant dry weight and up to 10% in spike weight. The values of 1000-grain weight showed an enhancement of 5.6-8.4%, compared with T1 (recommended doses of fertilizers). A positive correlation was observed between soil nutrient availability at mid crop stage and plant biometrical parameters at harvest stage. This study revealed the promise of such microalgal consortia as a biofertilizer for 25% N savings and improved yields of wheat crop.

  7. Biogeochemical Indicators in High- and Low-Arctic Marine and Terrestrial Avian Community Changes: Comparative Isotopic (13C, 15N, and 34S) Studies in Alaska and Greenland

    Science.gov (United States)

    Causey, D.; Bargmann, N. A.; Burnham, K. K.; Burnham, J. L.; Padula, V. M.; Johnson, J. A.; Welker, J. M.

    2011-12-01

    Understanding the complex dynamics of environmental change in northern latitudes is of paramount importance today, given documented rapid shifts in sea ice, plant phenology, temperatures, deglaciation, and habitat fidelity. This knowledge is particularly critical for Arctic avian communities, which are integral components by which biological teleconnections are maintained between the mid and northern latitudes. Furthermore, Arctic birds are fundamental to Native subsistence lifestyles and a focus for conservation activities. Avian communities of marine and terrestrial Arctic environments represent a broad spectrum of trophic levels, from herbivores (eg., geese Chen spp.), planktivores (eg., auklets Aethia spp.), and insectivores (eg., passerines: Wheatears Oenanthe spp., Longspurs Calcarius spp.), to predators of marine invertebrates (eg., eiders Somateria spp.), nearshore and offshore fish (eg., cormorants Phalacrocorax spp, puffins Fratercula spp.), even other bird species (eg., gulls Larus spp., falcons Peregrinus spp.). This diversity of trophic interconnections is an integral factor in the dynamics of Arctic ecosystem ecology, and they are key indicators for the strength and trajectories of change. We are especially interested in their feeding ecology, using stable isotope-diet relations to examine historical diets and to predict future feeding ecology by this range of species. Since 2009, we have been studying the foodweb ecology using stable isotopes (δ13C, δ15N, δ34S) of contemporaneous coastal and marine bird communities in High Arctic (Northwest Greenland) and Low Arctic (western Aleutian Islands, AK). We are quantifying the isotopic values of blood, organ tissues, and feathers, and have carried out comparisons between native and lipid-extracted samples. Although geographically distant, these communities comprise similar taxonomic and ecological congeners, including several species common to both (eg., Common Eider, Black-legged Kittiwake, Northern

  8. Encapsulation of Multiple Microalgal Cells via a Combination of Biomimetic Mineralization and LbL Coating

    Directory of Open Access Journals (Sweden)

    Minjeong Kim

    2018-02-01

    Full Text Available The encapsulation of living cells is appealing for its various applications to cell-based sensors, bioreactors, biocatalysts, and bioenergy. In this work, we introduce the encapsulation of multiple microalgal cells in hollow polymer shells of rhombohedral shape by the following sequential processes: embedding of microalgae in CaCO3 crystals; layer-by-layer (LbL coating of polyelectrolytes; and removal of sacrificial crystals. The microcapsule size was controlled by the alteration of CaCO3 crystal size, which is dependent on CaCl2/Na2CO3 concentration. The microalgal cells could be embedded in CaCO3 crystals by a two-step process: heterogeneous nucleation of crystal on the cell surface followed by cell embedment by the subsequent growth of crystal. The surfaces of the microalgal cells were highly favorable for the crystal growth of calcite; thus, micrometer-sized microalgae could be perfectly occluded in the calcite crystal without changing its rhombohedral shape. The surfaces of the microcapsules, moreover, could be decorated with gold nanoparticles, Fe3O4 magnetic nanoparticles, and carbon nanotubes (CNTs, by which we would expect the functionalities of a light-triggered release, magnetic separation, and enhanced mechanical and electrical strength, respectively. This approach, entailing the encapsulation of microalgae in semi-permeable and hollow polymer microcapsules, has the potential for application to microbial-cell immobilization for high-biomass-concentration cultivation as well as various other bioapplications.

  9. Encapsulation of Multiple Microalgal Cells via a Combination of Biomimetic Mineralization and LbL Coating.

    Science.gov (United States)

    Kim, Minjeong; Choi, Myoung Gil; Ra, Ho Won; Park, Seung Bin; Kim, Yong-Joo; Lee, Kyubock

    2018-02-13

    The encapsulation of living cells is appealing for its various applications to cell-based sensors, bioreactors, biocatalysts, and bioenergy. In this work, we introduce the encapsulation of multiple microalgal cells in hollow polymer shells of rhombohedral shape by the following sequential processes: embedding of microalgae in CaCO₃ crystals; layer-by-layer (LbL) coating of polyelectrolytes; and removal of sacrificial crystals. The microcapsule size was controlled by the alteration of CaCO₃ crystal size, which is dependent on CaCl₂/Na₂CO₃ concentration. The microalgal cells could be embedded in CaCO₃ crystals by a two-step process: heterogeneous nucleation of crystal on the cell surface followed by cell embedment by the subsequent growth of crystal. The surfaces of the microalgal cells were highly favorable for the crystal growth of calcite; thus, micrometer-sized microalgae could be perfectly occluded in the calcite crystal without changing its rhombohedral shape. The surfaces of the microcapsules, moreover, could be decorated with gold nanoparticles, Fe₃O₄ magnetic nanoparticles, and carbon nanotubes (CNTs), by which we would expect the functionalities of a light-triggered release, magnetic separation, and enhanced mechanical and electrical strength, respectively. This approach, entailing the encapsulation of microalgae in semi-permeable and hollow polymer microcapsules, has the potential for application to microbial-cell immobilization for high-biomass-concentration cultivation as well as various other bioapplications.

  10. Nile Red Staining for Oil Determination in Microalgal Cells: A New Insight through Statistical Modelling

    Directory of Open Access Journals (Sweden)

    Ronald Halim

    2015-01-01

    Full Text Available In the wake of global warming and rapid fossil fuel depletion, microalgae emerge as promising feedstocks for sustainable biofuel production. Nile red staining acts as a rapid diagnostic tool to measure the amount of biodiesel-convertible lipid that the cells accumulate. There is a need for the development of a more uniform staining procedure. In its first phase, this study examined the dependence of microalgal Nile red fluorescence (Tetraselmis suecica in terms of its most pertinent staining variables. A quadratic surface model that successfully described the Nile red fluorescence intensity as a composite function of its variables was generated (r2=0.86. Cell concentration was shown to have a significant effect on the fluorescence intensity. Up to a certain threshold, fluorescence intensity was shown to increase with Nile red dye concentration. In its second phase, the study reviewed findings from previous Nile red studies to elucidate some of the fundamental mechanism underlying the diffusion of Nile red dye molecules into the microalgal cells and their subsequent interaction with intracellular lipids. Through the review process, we were able to develop a simple framework that provided a set of guidelines for the standardization of the Nile red staining procedure across different microalgal species.

  11. SIMULATION OF MICROALGAL GROWTH IN A CONTINUOUS PHOTOBIOREACTOR WITH SEDIMENTATION AND PARTIAL BIOMASS RECYCLING

    Directory of Open Access Journals (Sweden)

    C. E. de Farias Silva

    Full Text Available Abstract Microalgae are considered as promising feedstocks for the third generation of biofuels. They are autotrophic organisms with high growth rate and can stock an enormous quantity of lipids (about 20 - 40% of their dried cellular weight. This work was aimed at studying the cultivation of Scenedesmus obliquus in a two-stage system composed of a photobioreactor and a settler to concentrate and partially recycle the biomass as a way to enhance the microalgae cellular productivity. It was attempted to specify by simulation and experimental data a relationship between the recycling rate, kinetic parameters of microalgal growth and photobioreactor operating conditions. Scenedesmus obliquus cells were cultivated in a lab-scale flat-plate reactor, homogenized by aeration, and running in continuous flow with a residence time of 1.66 day. Experimental data for the microalgal growth were used in a semi-empirical simulation model. The best results were obtained for Fw=0.2FI, when R = 1 and kd = 0 and 0.05 day-1, with the biomass production in the reactor varying between 8 g L -1 and 14 g L-1, respectively. The mathematical model fitted to the microalgal growth experimental data was appropriate for predicting the efficiency of the reactor in producing Scenedesmus obliquus cells, establishing a relation between cellular productivity and the minimum recycling rate that must be used in the system.

  12. Comparative Evaluation of Anaerobic Bacterial Communities Associated with Roots of Submerged Macrophytes Growing in Marine or Brackish Water Sediments

    Science.gov (United States)

    Sediment microbial communities are important for seagrass growth and carbon cycling, however relatively few studies have addressed the composition of prokaryotic communities in seagrass bed sediments. Selective media were used enumerate culturable anaerobic bacteria associated ...

  13. QUANTIFICATION OF RECA GENE EXPRESSION AS AN INDICATOR OF REPAIR POTENTIAL IN MARINE BACTERIOPLANKTON COMMUNITIES OF ANTARCTICA.

    Science.gov (United States)

    Marine bacteria in surface waters must cope daily with the damaging effects of exposure to solar radiation (containing both UV-A and UV-B wavelengths), which produces lesions in their DNA. As the stratospheric ozone layer is depleted, these coping mechanisms are likely to play an...

  14. Trends in records and contribution of non-indigenous species (NIS) to biotic communities in Danish marine waters

    DEFF Research Database (Denmark)

    Stæhr, Peter Anton; Jakobsen, Hans Henrik; Hansen, Jørgen L.S.

    The report investigates trends in the temporal and spatial changes of non-indigenous marine species in the Danish part of the OSPAR and HELCOM regions. The assessment is based on a quantitative analysis of data available in national monitoring databases and covers the period 1989 to 2014 and othe...

  15. Marine subsidies of island communities in the Gulf of California: evidence from stable carbon and nitrogen isotopes

    International Nuclear Information System (INIS)

    Anderson, W.B.; Polis, G.A.

    1998-01-01

    Coastal sites support larger (2 to > 100 x) populations of many consumers than inland sites on islands in the Gulf of California. Previous data suggested that subsidies of energy and nutrients from the ocean allowed large coastal populations. Stable carbon and nitrogen isotopes are frequently used to analyse diet composition of organisms: they are particularly useful to distinguish between diet sources with distinct isotopic signatures, such as marine and terrestrial diets. We analyzed the 13 C and 15 N concentrations of coastal versus inland spiders and scorpions to test the hypothesis that coastal individuals exhibited more strongly marine-based diets than inland individuals. Coastal spiders and scorpions were significantly more enriched in 13 C and 15 N than inland spiders and scorpions, suggesting that the coastal individuals consumed more marine-based foods than their inland counterparts. These patterns existed in both drought years and wet El Nino years. However, the marine influence was stronger in drought years when terrestrial productivity was nearly non-existent, than in wet years when terrestrial productivity increased by an order of magnitude. (au)

  16. Modelling marine community responses to climate-driven species redistribution to guide monitoring and adaptive ecosystem-based management

    NARCIS (Netherlands)

    Marzloff, Martin Pierre; Melbourne-Thomas, Jessica; Hamon, Katell G.; Hoshino, Eriko; Jennings, Sarah; Putten, Van Ingrid E.; Pecl, Gretta T.

    2016-01-01

    As a consequence of global climate-driven changes, marine ecosystems are experiencing polewards redistributions of species – or range shifts – across taxa and throughout latitudes worldwide. Research on these range shifts largely focuses on understanding and predicting changes in the distribution of

  17. Identifying Sources of Marine Litter

    OpenAIRE

    VEIGA Joana Mira; FLEET David; KINSEY Sue; NILSSON Per; VLACHOGIANNI Thomais; WERNER Stefanie; GALGANI Francois; THOMPSON Richard; DAGEVOS Jeroen; GAGO Jesus; SOBRAL Paula; CRONIN Richard

    2016-01-01

    Marine litter is a global problem causing harm to marine wildlife, coastal communities and maritime activities. It also embodies an emerging concern for human health and safety. The reduction of marine litter pollution poses a complex challenge for humankind, requiring adjustments in human behaviour as well as in the different phases of the life-cycle of products and across multiple economic sectors. The Marine Strategy Framework Directive (MSFD) requires European Member States to monitor...

  18. Gendered Disparities in Quality of Cataract Surgery in a Marginalised Population in Pakistan: The Karachi Marine Fishing Communities Eye and General Health Survey.

    Directory of Open Access Journals (Sweden)

    Khabir Ahmad

    Full Text Available Marine fishing communities are among the most marginalised and hard-to-reach groups and have been largely neglected in health research. We examined the quality of cataract surgery and its determinants, with an emphasis on gender, in marine fishing communities in Karachi, Pakistan, using multiple indicators of performance.The Karachi Marine Fishing Communities Eye and General Health Survey was a door-to-door, cross-sectional study conducted between March 2009 and April 2010 in fishing communities living on 7 islands and in coastal areas in Keamari, Karachi, located on the Arabian Sea. A population-based sample of 638 adults, aged ≥ 50 years, was studied. A total of 145 eyes (of 97 persons had undergone cataract surgery in this sample. Cataract surgical outcomes assessed included vision (presenting and best-corrected with a reduced logMAR chart, satisfaction with surgery, astigmatism, and pupil shape. Overall, 65.5% of the operated eyes had some form of visual loss (presenting visual acuity [PVA] < 6/12. 55.2%, 29.0%, and 15.9% of these had good, borderline, and poor visual outcomes based on presenting vision; with best correction, these values were: 68.3 %, 18.6%, and 13.1%, respectively. Of 7 covariates evaluated in the multivariable generalized estimating equations (GEE analyses, gender was the only significant independent predictor of visual outcome. Women's eyes were nearly 4.38 times more likely to have suboptimal visual outcome (PVA<6/18 compared with men's eyes (adjusted odds ratio 4.38, 95% CI 1.96-9.79; P<0.001 after adjusting for the effect of household financial status. A higher proportion of women's than men's eyes had an irregular pupil (26.5% vs. 14.8% or severe/very severe astigmatism (27.5% vs. 18.2%. However, these differences did not reach statistical significance. Overall, more than one fourth (44/144 of cataract surgeries resulted in dissatisfaction. The only significant predictor of satisfaction was visual outcome (P <0

  19. Use of real-time qPCR to quantify members of the unculturable heterotrophic bacterial community in a deep sea marine sponge, Vetulina sp.

    Science.gov (United States)

    Cassler, M; Peterson, C L; Ledger, A; Pomponi, S A; Wright, A E; Winegar, R; McCarthy, P J; Lopez, J V

    2008-04-01

    In this report, real-time quantitative PCR (TaqMan qPCR) of the small subunit (SSU) 16S-like rRNA molecule, a universal phylogenetic marker, was used to quantify the relative abundance of individual bacterial members of a diverse, yet mostly unculturable, microbial community from a marine sponge. Molecular phylogenetic analyses of bacterial communities derived from Caribbean Lithistid sponges have shown a wide diversity of microbes that included at least six major subdivisions; however, very little overlap was observed between the culturable and unculturable microbial communities. Based on sequence data of three culture-independent Lithistid-derived representative bacteria, we designed probe/primer sets for TaqMan qPCR to quantitatively characterize selected microbial residents in a Lithistid sponge, Vetulina, metagenome. TaqMan assays included specificity testing, DNA limit of detection analysis, and quantification of specific microbial rRNA sequences such as Nitrospira-like microbes and Actinobacteria up to 172 million copies per microgram per Lithistid sponge metagenome. By contrast, qPCR amplification with probes designed for common previously cultured sponge-associated bacteria in the genera Rheinheimera and Marinomonas and a representative of the CFB group resulted in only minimal detection of the Rheiheimera in total DNA extracted from the sponge. These data verify that a large portion of the microbial community within Lithistid sponges may consist of currently unculturable microorganisms.

  20. Open Data, Jupyter Notebooks and Geospatial Data Standards Combined - Opening up large volumes of marine and climate data to other communities

    Science.gov (United States)

    Clements, O.; Siemen, S.; Wagemann, J.

    2017-12-01

    The EU-funded Earthserver-2 project aims to offer on-demand access to large volumes of environmental data (Earth Observation, Marine, Climate data and Planetary data) via the interface standard Web Coverage Service defined by the Open Geospatial Consortium. Providing access to data via OGC web services (e.g. WCS and WMS) has the potential to open up services to a wider audience, especially to users outside the respective communities. Especially WCS 2.0 with its processing extension Web Coverage Processing Service (WCPS) is highly beneficial to make large volumes accessible to non-expert communities. Users do not have to deal with custom community data formats, such as GRIB for the meteorological community, but can directly access the data in a format they are more familiar with, such as NetCDF, JSON or CSV. Data requests can further directly be integrated into custom processing routines and users are not required to download Gigabytes of data anymore. WCS supports trim (reduction of data extent) and slice (reduction of data dimension) operations on multi-dimensional data, providing users a very flexible on-demand access to the data. WCPS allows the user to craft queries to run on the data using a text-based query language, similar to SQL. These queries can be very powerful, e.g. condensing a three-dimensional data cube into its two-dimensional mean. However, the more processing-intensive the more complex the query. As part of the EarthServer-2 project, we developed a python library that helps users to generate complex WCPS queries with Python, a programming language they are more familiar with. The interactive presentation aims to give practical examples how users can benefit from two specific WCS services from the Marine and Climate community. Use-cases from the two communities will show different approaches to take advantage of a Web Coverage (Processing) Service. The entire content is available with Jupyter Notebooks, as they prove to be a highly beneficial tool

  1. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

    OpenAIRE

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

    2012-01-01

    Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the p...

  2. Transcriptional Activities of the Microbial Consortium Living with the Marine Nitrogen-Fixing Cyanobacterium Trichodesmium Reveal Potential Roles in Community-Level Nitrogen Cycling.

    Science.gov (United States)

    Lee, Michael D; Webb, Eric A; Walworth, Nathan G; Fu, Fei-Xue; Held, Noelle A; Saito, Mak A; Hutchins, David A

    2018-01-01

    Trichodesmium is a globally distributed cyanobacterium whose nitrogen-fixing capability fuels primary production in warm oligotrophic oceans. Like many photoautotrophs, Trichodesmium serves as a host to various other microorganisms, yet little is known about how this associated community modulates fluxes of environmentally relevant chemical species into and out of the supraorganismal structure. Here, we utilized metatranscriptomics to examine gene expression activities of microbial communities associated with Trichodesmium erythraeum (strain IMS101) using laboratory-maintained enrichment cultures that have previously been shown to harbor microbial communities similar to those of natural populations. In enrichments maintained under two distinct CO 2 concentrations for ∼8 years, the community transcriptional profiles were found to be specific to the treatment, demonstrating a restructuring of overall gene expression had occurred. Some of this restructuring involved significant increases in community respiration-related transcripts under elevated CO 2 , potentially facilitating the corresponding measured increases in host nitrogen fixation rates. Particularly of note, in both treatments, community transcripts involved in the reduction of nitrate, nitrite, and nitrous oxide were detected, suggesting the associated organisms may play a role in colony-level nitrogen cycling. Lastly, a taxon-specific analysis revealed distinct ecological niches of consistently cooccurring major taxa that may enable, or even encourage, the stable cohabitation of a diverse community within Trichodesmium consortia. IMPORTANCE Trichodesmium is a genus of globally distributed, nitrogen-fixing marine cyanobacteria. As a source of new nitrogen in otherwise nitrogen-deficient systems, these organisms help fuel carbon fixation carried out by other more abundant photoautotrophs and thereby have significant roles in global nitrogen and carbon cycling. Members of the Trichodesmium genus tend to

  3. PENGEMBANGAN PARIWISATA BAHARI BERBASIS MASYARAKAT DI PULAU KALEDUPA, KABUPATEN WAKATOBI, PROVINSI SULAWESI TENGGARA (Community Based Marine Tourism Development in Kaledupa Island, Wakatobi Regency, South East Sulawesi Province

    Directory of Open Access Journals (Sweden)

    Hadiwijaya Lesmana Salim

    2015-11-01

    Full Text Available ABSTRAK Tujuan penelitian adalah mengetahui pengembangan pariwisata bahari berbasis masyarakat di Pulau Kaledupa dan sekitarnya, Kabupaten Wakatobi, Provinsi Sulawesi Tenggara. Penelitian dilakukan pada bulan Oktober – November 2014. Penelitian menggunakan metode analisis prospektif partisipatif, wawancara, analisis pengaruh antar-variabel kunci, membangun skenario, dan analisis implikasi strategis dan aksi antisipatif. Hasil penelitian menunjukkan bahwa terdapat tiga variabel utama yang harus dititikberatkan dalam pengembangan wisata bahari di Pulau Kaledupa dan sekitarnya, yaitu informatif, koordinasi antar instansi, dan sumberdaya alam. Penitikberatan pada ketiga variabel tersebut diharapkan dapat menghilangkan kesalahpahaman dan kesalahpenafsiran atas informasi yang diberikan sehingga dapat menunjang hubungan yang harmonis antar pemangku kepentingan pengembangan wisata bahari. Koordinasi yang harmonis diharapkan dapat mensinergikan antar perencanaan, pengembangan dan pengelolaan. Diharapkan pula sumberdaya alam yang ada berkesinambungan tanpa mengurangi dan merusak kualitasnya.   ABSTRACT The research on community based marine tourism development at Kaledupa island has been conducted on October – November 2014. This research used participatory prospective analysis, interview, Influence Analysis of inter key variables, scenario building, and Analysis of Strategic Implication and Anticipative act. The result shows that there are three key variables that should be focused on marine tourism development at Kaledupa island i.e informative, inter-institutions coordination, and natural resources. These variables should be focused in order to relieve misconception and misinterpretation on information which is given, so that it can support harmonic relationship between marine tourism stakeholders. The synergy of planning, development, and management can be expected from harmonic coordination. It is also expected that existing natural resources

  4. Microalgal carbohydrates: an overview of the factors influencing carbohydrates production, and of main bioconversion technologies for production of biofuels

    DEFF Research Database (Denmark)

    Markou, Giorgos; Angelidaki, Irini; Georgakakis, Dimitris

    2012-01-01

    in research is the cultivation of microalgae for lipids production to generate biodiesel. However, there are several other biological or thermochemical conversion technologies, in which microalgal biomass could be used as substrate. However, the high protein content or the low carbohydrate content...... of the majority of the microalgal species might be a constraint for their possible use in these technologies. Moreover, in the majority of biomass conversion technologies, carbohydrates are the main substrate for production of biofuels. Nevertheless, microalgae biomass composition could be manipulated by several......Microalgal biomass seems to be a promising feedstock for biofuel generation. Microalgae have relative high photosynthetic efficiencies, high growth rates, and some species can thrive in brackish water or seawater and wastewater from the food- and agro-industrial sector. Today, the main interest...

  5. Role of environmental factors for the vertical distribution (0–1000 m of marine bacterial communities in the NW Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    J. F. Ghiglione

    2008-12-01

    Full Text Available Bacterioplankton plays a central role in energy and matter fluxes in the sea, yet the factors that constrain its variation in marine systems are still poorly understood. Here we use the explanatory power of direct multivariate gradient analysis to evaluate the driving forces exerted by environmental parameters on bacterial community distribution in the water column. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea. This station is characterized by very poor horizontal advection currents which makes it an ideal model to test hypotheses on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behind bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extent temperature, oxygen, dissolved organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of organic matter sources and fates suggested that bacterial community structure in the surface layers was in part explained by lipids of chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth.

  6. Community cascades in a marine pelagic food web controlled by the non-visual apex predator Mnemiopsis leidyi

    DEFF Research Database (Denmark)

    Tiselius, Peter; Møller, Lene Friis

    2017-01-01

    Trophic cascades are a ubiquitous feature of many terrestrial and fresh-water food webs, but have been difficult to demonstrate in marine systems with multispecies trophic levels. Here we describe significant trophic cascades in an open coastal planktonic ecosystem exposed to an introduced top...... predator. The ctenophore Mnemiopsis leidyi was monitored for an 8-year period concurrent with measures of the food web structure of the plankton and strong trophic cascades were evident. In the 5 years when M. leidyi were found, their target prey (grazing copepods) were reduced 5-fold and the primary...

  7. The impact of temperature change on the activity and community composition of sulfate-reducing bacteria in arctic versus temperate marine sediments

    DEFF Research Database (Denmark)

    Robador, Alberto; Brüchert, Volker; Jørgensen, Bo Barker

    2009-01-01

    Arctic regions may be particularly sensitive to climate warming and, consequently, rates of carbon mineralization in warming marine sediment may also be affected. Using long-term (24 months) incubation experiments at 0°C, 10°C and 20°C, the temperature response of metabolic activity and community...... composition of sulfate-reducing bacteria were studied in the permanently cold sediment of north-western Svalbard (Arctic Ocean) and compared with a temperate habitat with seasonally varying temperature (German Bight, North Sea). Short-term 35S-sulfate tracer incubations in a temperature-gradient block...... (between -3.5°C and +40°C) were used to assess variations in sulfate reduction rates during the course of the experiment. Warming of arctic sediment resulted in a gradual increase of the temperature optima (Topt) for sulfate reduction suggesting a positive selection of psychrotolerant/mesophilic sulfate...

  8. A framework of lessons learned from community-based marine reserves and its effectiveness in guiding a new coastal management initiative in the Philippines.

    Science.gov (United States)

    Beger, Maria; Harborne, Alastair R; Dacles, Terence P; Solandt, Jean-Luc; Ledesma, Gerardo L

    2004-12-01

    Community-based coastal resource management has been widely applied within the Philippines. However, small-scale community-based reserves are often inefficient owing to management inadequacies arising because of a lack of local support or enforcement or poor design. Because there are many potential pitfalls during the establishment of even small community-based reserves, it is important for coastal managers, communities, and facilitating institutions to have access to a summary of the key factors for success. Reviewing relevant literature, we present a framework of "lessons learned" during the establishment of protected areas, mainly in the Philippines. The framework contains summary guidance on the importance of (1) an island location, (2) small community population size, (3) minimal effect of land-based development, (4) application of a bottom-up approach, (5) an external facilitating institution, (6) acquisition of title, (7) use of a scientific information database, (8) stakeholder involvement, (9) the establishment of legislation, (10) community empowerment, (11) alternative livelihood schemes, (12) surveillance, (13) tangible management results, (14) continued involvement of external groups after reserve establishment, and (15) small-scale project expansion.These framework components guided the establishment of a community-based protected area at Danjugan Island, Negros Occidental, Philippines. This case study showed that the framework was a useful guide that led to establishing and implementing a community-based marine reserve. Evaluation of the reserve using standard criteria developed for the Philippines shows that the Danjugan Island protected area can be considered successful and sustainable. At Danjugan Island, all of the lessons synthesized in the framework were important and should be considered elsewhere, even for relatively small projects. As shown in previous projects in the Philippines, local involvement and stewardship of the protected area

  9. Enrichment using an up-flow column reactor and community structure of marine anammox bacteria from coastal sediment.

    Science.gov (United States)

    Kindaichi, Tomonori; Awata, Takanori; Suzuki, Yuji; Tanabe, Katsuichiro; Hatamoto, Masashi; Ozaki, Noriatsu; Ohashi, Akiyoshi

    2011-01-01

    We established an enrichment culture of marine anaerobic ammonium oxidation (anammox) bacteria using an up-flow column reactor fed with artificial sea water supplemented with nitrogen and minerals and inoculated with coastal surface sediment collected from Hiroshima Bay. After 2 months of reactor operation, simultaneous removal of NH(4)(+) and NO(2)(-) was observed, suggesting that an anammox reaction was proceeding. A total nitrogen removal rate of 2.17 g-N L(-1) day(-1) was attained on day 594 while the nitrogen loading rate was 3.33 g-N L(-1) day(-1). Phylogenetic analysis revealed that at least two dominant "Candidatus Scalindua" species were present in this reactor. Moreover, many uncultured bacteria and archaea, including candidate division or ammonia-oxidizing archaea, were present. Fluorescence in situ hybridization (FISH) revealed that anammox bacteria accounted for 85.5 ± 4.5% of the total bacteria at day 393. We also designed two oligonucleotide probes specific to each dominant "Candidatus Scalindua" species. A simultaneous FISH analysis using both probes showed that two different "Candidatus Scalindua" species were clearly recognizable and coexisted during reactor operation, although there was some variation in their abundance. The marine anammox bacteria enriched in this study have potential applications to the treatment of industrial wastewater containing high levels of ammonium and salt.

  10. Effects of co-products on the life-cycle impacts of microalgal biodiesel.

    Science.gov (United States)

    Soratana, Kullapa; Barr, William J; Landis, Amy E

    2014-05-01

    Microalgal biodiesel production has been investigated for decades, yet it is not commercially available. Part of the problem is that the production process is energy and chemical intensive due, in part, to the high portion of microalgal biomass left as residues. This study investigated cradle-to-gate life-cycle environmental impacts from six different scenarios of microalgal biodiesel and its co-products. Ozone depletion, global warming, photochemical smog formation, acidification and eutrophication potentials were assessed using the Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI). Monte Carlo Analysis was conducted to investigate the processes with major contribution in each impact category. The market opportunity for each co-product was examined based on supply, demand and prices of the products that could potentially be substituted by the co-products. The results indicated that the scenario with the least life-cycle environmental impacts in all the five impact categories with the highest net energy ratio was the scenario utilizing a multitude of co-products including bioethanol from lipid-extracted microalgae (LEA), biomethane (to produce electricity and heat) from simultaneous saccharification-fermentation (SSF) residues, land-applied material from SSF residue anaerobic digestion (AD) solid digestate, recycling nutrients from SSF residue AD liquid digestate and CO2 recovered from SSF process contributed. Decreasing the energy consumption of the centrifuge in the land-applied material production process and increasing the lipid content of microalgae can reduce environmental footprints of the co-products. The same scenario also had the highest total income indicating their potential as co-products in the market. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. A simple, reproducible and sensitive spectrophotometric method to estimate microalgal lipids

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yimin [ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Vaidyanathan, Seetharaman, E-mail: s.vaidyanathan@sheffield.ac.uk [ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2012-04-29

    Highlights: Black-Right-Pointing-Pointer FAs released from lipids form complex with Cu-TEA in chloroform. Black-Right-Pointing-Pointer The FA-Cu-TEA complex gives strong absorbance at 260 nm. Black-Right-Pointing-Pointer The absorbance is sensitive and independent of C-atom number in the FAs (10-18). Black-Right-Pointing-Pointer Microalgal lipid extract and pure FA (such as C16) can both be used as standards. - Abstract: Quantification of total lipids is a necessity for any study of lipid production by microalgae, especially given the current interest in microalgal carbon capture and biofuels. In this study, we employed a simple yet sensitive method to indirectly measure the lipids in microalgae by measuring the fatty acids (FA) after saponification. The fatty acids were reacted with triethanolamine-copper salts (TEA-Cu) and the ternary TEA-Cu-FA complex was detected at 260 nm using a UV-visible spectrometer without any colour developer. The results showed that this method could be used to analyse low levels of lipids in the range of nano-moles from as little as 1 mL of microalgal culture. Furthermore, the structure of the TEA-Cu-FA complex and related reaction process are proposed to better understand this assay. There is no special instrument required and the method is very reproducible. To the best of our knowledge, this is the first report of the use of UV absorbance of copper salts with FA as a method to estimate lipids in algal cultures. It will pave the way for a more convenient assay of lipids in microalgae and can readily be expanded for estimating lipids in other biological systems.

  12. A simple, reproducible and sensitive spectrophotometric method to estimate microalgal lipids

    International Nuclear Information System (INIS)

    Chen Yimin; Vaidyanathan, Seetharaman

    2012-01-01

    Highlights: ► FAs released from lipids form complex with Cu–TEA in chloroform. ► The FA–Cu–TEA complex gives strong absorbance at 260 nm. ► The absorbance is sensitive and independent of C-atom number in the FAs (10–18). ► Microalgal lipid extract and pure FA (such as C16) can both be used as standards. - Abstract: Quantification of total lipids is a necessity for any study of lipid production by microalgae, especially given the current interest in microalgal carbon capture and biofuels. In this study, we employed a simple yet sensitive method to indirectly measure the lipids in microalgae by measuring the fatty acids (FA) after saponification. The fatty acids were reacted with triethanolamine–copper salts (TEA–Cu) and the ternary TEA–Cu–FA complex was detected at 260 nm using a UV–visible spectrometer without any colour developer. The results showed that this method could be used to analyse low levels of lipids in the range of nano-moles from as little as 1 mL of microalgal culture. Furthermore, the structure of the TEA–Cu–FA complex and related reaction process are proposed to better understand this assay. There is no special instrument required and the method is very reproducible. To the best of our knowledge, this is the first report of the use of UV absorbance of copper salts with FA as a method to estimate lipids in algal cultures. It will pave the way for a more convenient assay of lipids in microalgae and can readily be expanded for estimating lipids in other biological systems.

  13. Inhibitory activities of microalgal extracts against Epstein-Barr Virus (EBV antigen expression in lymphoblastoid cells

    Directory of Open Access Journals (Sweden)

    Koh Yih Yih

    2014-01-01

    Full Text Available The inhibitory activities of microalgal extracts against the expression of three EBV antigens, latent membrane protein (LMP1, Epstein-Barr nuclear antigen (EBNA1 and Z Epstein-Barr reactivation activator (ZEBRA were assessed by immunocytochemistry. The observation that the methanol extracts and their fractions from Ankistrodesmus convolutus, Synechococcus elongatus and Spirulina platensis exhibited inhibitory activity against EBV proteins in three Burkitt’s lymphoma cell lines at concentrations as low as 20 μg/ml suggests that microalgae could be a potential source of antiviral compounds against EBV.

  14. Microalgal process-monitoring based on high-selectivity spectroscopy tools: status and future perspectives

    DEFF Research Database (Denmark)

    Podevin, Michael Paul Ambrose; Fotidis, Ioannis; Angelidaki, Irini

    2018-01-01

    microalgae production towards process automation through multivariate process control (MVPC) and software sensors trained on “big data”. The paper will also include a comprehensive overview of off-line implementations of vibrational spectroscopy in microalgal research as it pertains to spectral...... contribution of this review is to present current and prospective advances of on-line and in-line process analytical technology (PAT), with high-selectivity – the capability of monitoring several analytes simultaneously – in the interest of improving product quality, productivity, and process automation...... interpretation and process automation to aid and motivate development....

  15. Growth and metabolic characteristics of oleaginous microalgal isolates from Nilgiri biosphere Reserve of India.

    Science.gov (United States)

    Thangavel, Kalaiselvi; Radha Krishnan, Preethi; Nagaiah, Srimeena; Kuppusamy, Senthil; Chinnasamy, Senthil; Rajadorai, Jude Sudhagar; Nellaiappan Olaganathan, Gopal; Dananjeyan, Balachandar

    2018-01-03

    Renewable energy for sustainable development is a subject of a worldwide debate since continuous utilization of non-renewable energy sources has a drastic impact on the environment and economy; a search for alternative energy resources is indispensable. Microalgae are promising and potential alternate energy resources for biodiesel production. Thus, our efforts were focused on surveying the natural diversity of microalgae for the production of biodiesel. The present study aimed at identification, isolation, and characterization of oleaginous microalgae from shola forests of Nilgiri Biosphere Reserve (NBR), the biodiversity hot spot of India, where the microalgal diversity has not yet been systematically investigated. Overall the higher biomass yield, higher lipid accumulation and thermotolerance observed in the isolated microalgal strains have been found to be the desirable traits for the efficient biodiesel production. Species composition and diversity analysis yielded ten potential microalgal isolates belonging to Chlorophyceae and Cyanophyceae classes. The chlorophytes exhibited higher growth rate, maximum biomass yield, and higher lipid accumulation than Cyanophyceae. Among the chlorophytes, the best performing strains were identified and represented by Acutodesmus dissociatus (TGA1), Chlorella sp. (TGA2), Chlamydomonadales sp. (TGA3) and Hindakia tetrachotoma (PGA1). The Chlamydomonadales sp. recorded with the highest growth rate, lipid accumulation and biomass yield of 0.28 ± 0.03 day -1 (μ exp ), 29.7 ± 0.69% and 134.17 ± 16.87 mg L -1  day -1 , respectively. It was also found to grow well at various temperatures, viz., 25 °C, 35 °C, and 45 °C, indicating its suitability for open pond cultivation. The fatty acid methyl ester (FAME) analysis of stationary phase cultures of selected four algal strains by tandem mass spectrograph showed C16:0, C18:1 and C18:3 as dominant fatty acids suitable for biodiesel production. All the three

  16. Colonization of Coral Communities in the Krakatau Islands Strict Marine Nature Reserve, Indonesia (Kolonisasi Komunitas Karang di Kepulanan Krakatau

    Directory of Open Access Journals (Sweden)

    Singgih Afifa Putra

    2014-06-01

    Full Text Available Pulau-pulau Krakatau memiliki dinamika secara geomorfologi, dan berbagai perubahan fisik yang berlangsung memberikan dampak terhadap biota, termasuk pada proses dan tingkat pergantian suksesi komunitasnya. Tujuan penelitian ini untuk menjelaskan kondisi terkini dan proses kolonisasi komunitas karang, termasuk status kerusakan komunitas karang dan disturbansi lingkungan yang mempengaruhinya. Line intercept transect dilakukan di enam stasiun pada dua kedalaman yang berbeda yakni 5 dan 10m. Sedangkan observasi terhadap komunitas koral dilakukan dengan perekaman video. Hasil penelitian ini menunjukkan bahwa suksesi atau perkembangan komunitas (i.e. kolonisasi karang yang dijumpai di Pulau Anak Krakatau masih mengindikasikan tahap awal kolonisasi, berbeda dengan komunitas karang yang dijumpai di Pulau Rakata dan Panjang. Diversifikasi komunitas karang di kedua pulau tersebut, menunjukkan dominansi spesies oportunis dan pioner (i.e. Pocillopora dan Seriatopora yang umum dijumpai di Anak Krakatau sudah tergantikan. Dominansi dari beberapa spesies karang telah mengindikasikan terjadinya proses eksklusi kompetitif di antara komunitas karang. Tiga tipe komunitas karang yang dijumpai dapat dibedakan menurut karakteristik masing-masing kawasan, yaitu komunitas kawasan terpapar, semi terpapar/terlindung, dan terlindung. Kerusakan komunitas karang di Krakatau berdasarkan kriteria indeks kerusakan karang (CDI sudah termasuk kedalam kategori wilayah “hot spot”, dimana sangat memerlukan perhatian, pengawasan, pengamatan atau restorasi komunitas karang. Hasil penelitian ini memberikan gambaran bahwa terjadinya kolonisasi dan tingkat kerusakan komunitas karang perlu menjadi acuan dalam pengelolaan kawasan terumbu karang di Cagar Alam Laut Krakatau. Kata kunci: kolonisasi, suksesi; komunitas karang; pengelolaan; Krakatau Krakatau Islands diversity is geomorphologically dynamic, and these physical changes influence on organisms including community successional

  17. Anaerobic digestion of microalgal biomass: Challenges, opportunities and research needs.

    Science.gov (United States)

    Gonzalez-Fernandez, Cristina; Sialve, Bruno; Molinuevo-Salces, Beatriz

    2015-12-01

    Integration of anaerobic digestion (AD) with microalgae processes has become a key topic to support economic and environmental development of this resource. Compared with other substrates, microalgae can be produced close to the plant without the need for arable lands and be fully integrated within a biorefinery. As a limiting step, anaerobic hydrolysis appears to be one of the most challenging steps to reach a positive economic balance and to completely exploit the potential of microalgae for biogas and fertilizers production. This review covers recent investigations dealing with microalgae AD and highlights research opportunities and needs to support the development of this resource. Novel approaches to increase hydrolysis rate, the importance of the reactor design and the noteworthiness of the microbial anaerobic community are addressed. Finally, the integration of AD with microalgae processes and the potential of the carboxylate platform for chemicals and biofuels production are reviewed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Three dimensional marine seismic survey has no measurable effect on species richness or abundance of a coral reef associated fish community

    International Nuclear Information System (INIS)

    Miller, Ian; Cripps, Edward

    2013-01-01

    Highlights: • A marine seismic survey was conducted at Scott Reef, North Western Australia. • Effects of the survey on demersal fish were gauged using underwater visual census. • There was no detectable impact of the seismic survey on species abundance. • There was no detectable impact of the seismic survey on species richness. -- Abstract: Underwater visual census was used to determine the effect of a three dimensional seismic survey on the shallow water coral reef slope associated fish community at Scott Reef. A census of the fish community was conducted on six locations at Scott Reef both before and after the survey. The census included small site attached demersal species belonging to the family Pomacentridae and larger roving demersal species belonging to the non-Pomacentridae families. These data were combined with a decade of historical data to assess the impact of the seismic survey. Taking into account spatial, temporal, spatio-temporal and observer variability, modelling showed no significant effect of the seismic survey on the overall abundance or species richness of Pomacentridae or non-Pomacentridae. The six most abundant species were also analysed individually. In all cases no detectable effect of the seismic survey was found on the abundance of these fish species at Scott Reef

  19. The difference biocultural "place" makes to community efforts towards sustainable development: Youth participatory action research in a marine protected area of Colombia

    Science.gov (United States)

    McRuer, Jennifer; Zethelius, Margarita

    2017-12-01

    The Latin American concept of "(collective) biocultural heritage" arose from Indigenous knowledge and practices with respect to local natural resources and environment, including the food being hunted, the crops being grown, and the landscapes being created. The term is now used more widely to describe community practices, goals and priorities that are determined, maintained and managed by diverse cultural relationships with "place". The study presented in this article investigated biocultural place relationships in connection with well-being and sustainability. In the context of learning and action for sustainability in Isla Grande, an island in a marine protected area of Colombia, this study targeted the significance of place to the everyday lives of Afro-Colombian youth - from their perspective. Beyond aiming to merely observe and collect data, the methodology included a research design which actively involved local youth and incorporated the aspect of place. The authors describe and reflect on the processes, learning and action that emerged throughout the research, as well as the study's limitations. They discuss broad implications in terms of how place relationships influence research, and how research influences place relationships. Local implications include supporting the voice of youth in community efforts to re-imagine and transform place relationships in response to critical place issues such as climate change, top-down resource management, privatisation, commodification and growing environmental injustice.

  20. Modelling an exploited marine fish community with 15 parameters - results from a simple size-based model

    NARCIS (Netherlands)

    Pope, J.G.; Rice, J.C.; Daan, N.; Jennings, S.; Gislason, H.

    2006-01-01

    To measure and predict the response of fish communities to exploitation, it is necessary to understand how the direct and indirect effects of fishing interact. Because fishing and predation are size-selective processes, the potential response can be explored with size-based models. We use a

  1. APPLICATION OF 3D COMPUTER-AIDED TOMOGRAPHY TO THE QUANTIFICATION OF MARINE SEDIMENT COMMUNITIES IN POLLUTION GRADIENTS

    Science.gov (United States)

    Computer-Aided Tomography (CT) has been demonstrated to be a cost efficient tool for the qualitative and quantitative study of estuarine benthic communities along pollution gradients.Now we have advanced this technology to successfully visualize and discriminate three dimen...

  2. 454 pyrosequencing to describe microbial eukaryotic community composition, diversity and relative abundance: a test for marine haptophytes.

    Directory of Open Access Journals (Sweden)

    Elianne Egge

    Full Text Available Next generation sequencing of ribosomal DNA is increasingly used to assess the diversity and structure of microbial communities. Here we test the ability of 454 pyrosequencing to detect the number of species present, and assess the relative abundance in terms of cell numbers and biomass of protists in the phylum Haptophyta. We used a mock community consisting of equal number of cells of 11 haptophyte species and compared targeting DNA and RNA/cDNA, and two different V4 SSU rDNA haptophyte-biased primer pairs. Further, we tested four different bioinformatic filtering methods to reduce errors in the resulting sequence dataset. With sequencing depth of 11000-20000 reads and targeting cDNA with Haptophyta specific primers Hap454 we detected all 11 species. A rarefaction analysis of expected number of species recovered as a function of sampling depth suggested that minimum 1400 reads were required here to recover all species in the mock community. Relative read abundance did not correlate to relative cell numbers. Although the species represented with the largest biomass was also proportionally most abundant among the reads, there was generally a weak correlation between proportional read abundance and proportional biomass of the different species, both with DNA and cDNA as template. The 454 sequencing generated considerable spurious diversity, and more with cDNA than DNA as template. With initial filtering based only on match with barcode and primer we observed 100-fold more operational taxonomic units (OTUs at 99% similarity than the number of species present in the mock community. Filtering based on quality scores, or denoising with PyroNoise resulted in ten times more OTU99% than the number of species. Denoising with AmpliconNoise reduced the number of OTU99% to match the number of species present in the mock community. Based on our analyses, we propose a strategy to more accurately depict haptophyte diversity using 454 pyrosequencing.

  3. Salt Effect on the Antioxidant Activity of Red Microalgal Sulfated Polysaccharides in Soy-Bean Formula

    Directory of Open Access Journals (Sweden)

    Ariela Burg

    2015-10-01

    Full Text Available Sulfated polysaccharides produced by microalgae, which are known to exhibit various biological activities, may potentially serve as natural antioxidant sources. To date, only a few studies have examined the antioxidant bioactivity of red microalgal polysaccharides. In this research, the effect of different salts on the antioxidant activities of two red microalgal sulfated polysaccharides derived from Porphyridium sp. and Porphyridium aerugineum were studied in a soy bean-based infant milk formula. Salt composition and concentration were both shown to affect the polysaccharides’ antioxidant activity. It can be postulated that the salt ions intefer with the polysaccharide chains’ interactions and alter their structure, leading to a new three-dimensional structure that better exposes antiooxidant sites in comparison to the polysaccharide without salt supplement. Among the cations that were studied, Ca2+ had the strongest enhancement effect on antioxidant activities of both polysaccharides. Understanding the effect of salts on polysaccharides’ stucture, in addition to furthering knowledge on polysaccharide bioactivities, may also shed light on the position of the antioxidant active sites.

  4. Salt Effect on the Antioxidant Activity of Red Microalgal Sulfated Polysaccharides in Soy-Bean Formula.

    Science.gov (United States)

    Burg, Ariela; Oshrat, Levy-Ontman

    2015-10-20

    Sulfated polysaccharides produced by microalgae, which are known to exhibit various biological activities, may potentially serve as natural antioxidant sources. To date, only a few studies have examined the antioxidant bioactivity of red microalgal polysaccharides. In this research, the effect of different salts on the antioxidant activities of two red microalgal sulfated polysaccharides derived from Porphyridium sp. and Porphyridium aerugineum were studied in a soy bean-based infant milk formula. Salt composition and concentration were both shown to affect the polysaccharides' antioxidant activity. It can be postulated that the salt ions intefer with the polysaccharide chains' interactions and alter their structure, leading to a new three-dimensional structure that better exposes antiooxidant sites in comparison to the polysaccharide without salt supplement. Among the cations that were studied, Ca(2+) had the strongest enhancement effect on antioxidant activities of both polysaccharides. Understanding the effect of salts on polysaccharides' stucture, in addition to furthering knowledge on polysaccharide bioactivities, may also shed light on the position of the antioxidant active sites.

  5. A Review on the Assessment of Stress conditions for Simultaneous Production of Microalgal Lipids and Carotenoids

    Directory of Open Access Journals (Sweden)

    Amritpreet kaur Minhas

    2016-05-01

    Full Text Available Microalgal species are potential resource of both biofuels and high-value metabolites, and their production is growth dependent. Growth parameters can be screened for the selection of novel microalgal species that produce molecules of interest. In this context our review confirms that, autotrophic and heterotrophic organisms have demonstrated a dual potential, namely the ability to produce lipids as well as value-added products (particularly carotenoids under influence of various physico-chemical stresses on microalgae. Some species of microalgae can synthesize, besides some pigments, very-long-chain polyunsaturated fatty acids (VL-PUFA,>20C such as docosahexaenoic acid and eicosapentaenoic acid, those have significant applications in food and health. Producing value-added by-products in addition to biofuels, fatty acid methyl esters (FAME, and lipids has the potential to improve microalgae-based biorefineries by employing either the autotrophic or the heterotrophic mode, which could be an offshoot of biotechnology. The review considers the potential of microalgae to produce a range of products and indicates future directions for developing suitable criteria for choosing novel isolates through bioprospecting large gene pool of microalga obtained from various habitats and climatic conditions.

  6. A Review on the Assessment of Stress Conditions for Simultaneous Production of Microalgal Lipids and Carotenoids

    Science.gov (United States)

    Minhas, Amritpreet K.; Hodgson, Peter; Barrow, Colin J.; Adholeya, Alok

    2016-01-01

    Microalgal species are potential resource of both biofuels and high-value metabolites, and their production is growth dependent. Growth parameters can be screened for the selection of novel microalgal species that produce molecules of interest. In this context our review confirms that, autotrophic and heterotrophic organisms have demonstrated a dual potential, namely the ability to produce lipids as well as value-added products (particularly carotenoids) under influence of various physico-chemical stresses on microalgae. Some species of microalgae can synthesize, besides some pigments, very-long-chain polyunsaturated fatty acids (VL-PUFA,>20C) such as docosahexaenoic acid and eicosapentaenoic acid, those have significant applications in food and health. Producing value-added by-products in addition to biofuels, fatty acid methyl esters (FAME), and lipids has the potential to improve microalgae-based biorefineries by employing either the autotrophic or the heterotrophic mode, which could be an offshoot of biotechnology. The review considers the potential of microalgae to produce a range of products and indicates future directions for developing suitable criteria for choosing novel isolates through bioprospecting large gene pool of microalga obtained from various habitats and climatic conditions. PMID:27199903

  7. Production of Microalgal Lipids as Biodiesel Feedstock with Fixation of CO2 by Chlorella vulgaris

    Directory of Open Access Journals (Sweden)

    Qiao Hu

    2014-01-01

    Full Text Available The global warming and shortage of energy are two critical problems for human social development. CO2 mitigation and replacing conventional diesel with biodiesel are effective routes to reduce these problems. Production of microalgal lipids as biodiesel feedstock by a freshwater microalga, Chlorella vulgaris, with the ability to fixate CO2 is studied in this work. The results show that nitrogen deficiency, CO2 volume fraction and photoperiod are the key factors responsible for the lipid accumulation in C. vulgaris. With 5 % CO2, 0.75 g/L of NaNO3 and 18:6 h of light/dark cycle, the lipid content and overall lipid productivity reached 14.5 % and 33.2 mg/(L·day, respectively. Furthermore, we proposed a technique to enhance the microalgal lipid productivity by activating acetyl-CoA carboxylase (ACCase with an enzyme activator. Citric acid and Mg2+ were found to be efficient enzyme activators of ACCase. With the addition of 150 mg/L of citric acid or 1.5 mmol/L of MgCl2, the lipid productivity reached 39.1 and 38.0 mg/(L·day, respectively, which was almost twofold of the control. This work shows that it is practicable to produce lipids by freshwater microalgae that can fixate CO2, and provides a potential route to solving the global warming and energy shortage problems.

  8. Microalgal-biochar immobilized complex: A novel efficient biosorbent for cadmium removal from aqueous solution.

    Science.gov (United States)

    Shen, Ying; Li, Huan; Zhu, Wenzhe; Ho, Shih-Hsin; Yuan, Wenqiao; Chen, Jianfeng; Xie, Youping

    2017-11-01

    The feasibility of the bioremediation of cadmium (Cd) using microalgal-biochar immobilized complex (MBIC) was investigated. Major operating parameters (e.g., pH, biosorbent dosage, initial Cd(II) concentration and microalgal-biochar ratio) were varied to compare the treatability of viable algae (Chlorella sp.), biochar and MBIC. The biosorption isotherms obtained by using algae or biochar were found to have satisfactory Langmuir predictions, while the best fitting adsorption isotherm model for MBIC was the Sips model. The maximum Cd(II) adsorption capacity of MBIC with a Chlorella sp.: biochar ratio of 2:3 (217.41mgg -1 ) was higher than that of Chlorella sp. (169.92mgg -1 ) or biochar (95.82mgg -1 ) alone. The pseudo-second-order model fitted the biosorption process of MBIC well (R 2 >0.999). Moreover, zeta potential, SEM and FTIR studies revealed that electrostatic attraction, ion exchange and surface complexation were the main mechanisms responsible for Cd removal when using MBIC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Ecotoxicological effects of enrofloxacin and its removal by monoculture of microalgal species and their consortium.

    Science.gov (United States)

    Xiong, Jiu-Qiang; Kurade, Mayur B; Jeon, Byong-Hun

    2017-07-01

    Enrofloxacin (ENR), a fluoroquinolone antibiotic, has gained big scientific concern due to its ecotoxicity on aquatic microbiota. The ecotoxicity and removal of ENR by five individual microalgae species and their consortium were studied to correlate the behavior and interaction of ENR in natural systems. The individual microalgal species (Scenedesmus obliquus, Chlamydomonas mexicana, Chlorella vulgaris, Ourococcus multisporus, Micractinium resseri) and their consortium could withstand high doses of ENR (≤1 mg L -1 ). Growth inhibition (68-81%) of the individual microalgae species and their consortium was observed in ENR (100 mg L -1 ) compared to control after 11 days of cultivation. The calculated 96 h EC 50 of ENR for individual microalgae species and microalgae consortium was 9.6-15.0 mg ENR L -1 . All the microalgae could recover from the toxicity of high concentrations of ENR during cultivation. The biochemical characteristics (total chlorophyll, carotenoid, and malondialdehyde) were significantly influenced by ENR (1-100 mg L -1 ) stress. The individual microalgae species and microalgae consortium removed 18-26% ENR at day 11. Although the microalgae consortium showed a higher sensitivity (with lower EC 50 ) toward ENR than the individual microalgae species, the removal efficiency of ENR by the constructed microalgae consortium was comparable to that of the most effective microalgal species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Microalgal Species Selection for Biodiesel Production Based on Fuel Properties Derived from Fatty Acid Profiles

    Directory of Open Access Journals (Sweden)

    Md. Nurun Nabi

    2013-10-01

    Full Text Available Physical and chemical properties of biodiesel are influenced by structural features of the fatty acids, such as chain length, degree of unsaturation and branching of the carbon chain. This study investigated if microalgal fatty acid profiles are suitable for biodiesel characterization and species selection through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE and Graphical Analysis for Interactive Assistance (GAIA analysis. Fatty acid methyl ester (FAME profiles were used to calculate the likely key chemical and physical properties of the biodiesel [cetane number (CN, iodine value (IV, cold filter plugging point, density, kinematic viscosity, higher heating value] of nine microalgal species (this study and twelve species from the literature, selected for their suitability for cultivation in subtropical climates. An equal-parameter weighted (PROMETHEE-GAIA ranked Nannochloropsis oculata, Extubocellulus sp. and Biddulphia sp. highest; the only species meeting the EN14214 and ASTM D6751-02 biodiesel standards, except for the double bond limit in the EN14214. Chlorella vulgaris outranked N. oculata when the twelve microalgae were included. Culture growth phase (stationary and, to a lesser extent, nutrient provision affected CN and IV values of N. oculata due to lower eicosapentaenoic acid (EPA contents. Application of a polyunsaturated fatty acid (PUFA weighting to saturation led to a lower ranking of species exceeding the double bond EN14214 thresholds. In summary, CN, IV, C18:3 and double bond limits were the strongest drivers in equal biodiesel parameter-weighted PROMETHEE analysis.

  11. Enhanced the energy outcomes from microalgal biomass by the novel biopretreatment

    International Nuclear Information System (INIS)

    He, Shuai; Fan, Xiaolei; Luo, Shengjun; Katukuri, Naveen Reddy; Guo, Rongbo

    2017-01-01

    Highlights: • The micro-aerobic pretreatment was used to improve energy yield of Chlorella sp. • The Bacillus licheniformis was confirmed to damage the cell wall of microalgae. • Obtained energy from Chlorella sp. was improved by 12.3%. • Pretreatment time was decreased from 60 h to 24 h. • The VS degradation efficiency was increased from 75.7% to 82.1%. - Abstract: Microalgae have been considered as one of the most promising biomass for the generation of biofuels. The anaerobic digestion (AD) has been proved to be a promising technique to transfer the microalgal biomass into biofuels. Previous study demonstrated that anaerobic pretreatment of microalgae biomass by Bacillus licheniformis could improve methane production. In this study micro-aerobic bio-pretreatment of microalgal biomass by the facultative anaerobic bacteria Bacillus licheniformis was invested with different loads of oxygen supplied. The bio-hydrogen and biomethane productions were tested to calculate total energy outcomes. The transmission electron microscope (TEM) photographs suggested that the novel micro-aerobic bio-pretreatment (MBP) could effectively damage the firm cell wall of algal cells. The processing time of the novel method (24 h) was less than the previous anaerobic pretreatment (60 h). Results showed that the group with 5 mL oxygen/g VS fed had the highest total energy outcomes, which was 17.6% higher than that of the anaerobic pretreatment.

  12. Comparative assessment of various lipid extraction protocols and optimization of transesterification process for microalgal biodiesel production.

    Science.gov (United States)

    Mandal, Shovon; Patnaik, Reeza; Singh, Amit Kumar; Mallick, Nirupama

    2013-01-01

    Biodiesel, using microalgae as feedstocks, is being explored as the most potent form of alternative diesel fuel for sustainable economic development. A comparative assessment of various protocols for microalgal lipid extraction was carried out using five green algae, six blue-green algae and two diatom species treated with different single and binary solvents both at room temperature and using a soxhlet. Lipid recovery was maximum with chloroform-methanol in the soxhlet extractor. Pretreatments ofbiomass, such as sonication, homogenization, bead-beating, lyophilization, autoclaving, microwave treatment and osmotic shock did not register any significant rise in lipid recovery. As lipid recovery using chloroform-methanol at room temperature demonstrated a marginally lower value than that obtained under the soxhlet extractor, on economical point of view, the former is recommended for microalgal total lipid extraction. Transesterification process enhances the quality of biodiesel. Experiments were designed to determine the effects of catalyst type and quantity, methanol to oil ratio, reaction temperature and time on the transesterification process using response surface methodology. Fatty acid methyl ester yield reached up to 91% with methanol:HCl:oil molar ratio of 82:4:1 at 65 degrees C for 6.4h reaction time. The biodiesel yield relative to the weight of the oil was found to be 69%.

  13. Microalgal process-monitoring based on high-selectivity spectroscopy tools: status and future perspectives.

    Science.gov (United States)

    Podevin, Michael; Fotidis, Ioannis A; Angelidaki, Irini

    2018-08-01

    Microalgae are well known for their ability to accumulate lipids intracellularly, which can be used for biofuels and mitigate CO 2 emissions. However, due to economic challenges, microalgae bioprocesses have maneuvered towards the simultaneous production of food, feed, fuel, and various high-value chemicals in a biorefinery concept. On-line and in-line monitoring of macromolecules such as lipids, proteins, carbohydrates, and high-value pigments will be more critical to maintain product quality and consistency for downstream processing in a biorefinery to maintain and valorize these markets. The main contribution of this review is to present current and prospective advances of on-line and in-line process analytical technology (PAT), with high-selectivity - the capability of monitoring several analytes simultaneously - in the interest of improving product quality, productivity, and process automation of a microalgal biorefinery. The high-selectivity PAT under consideration are mid-infrared (MIR), near-infrared (NIR), and Raman vibrational spectroscopies. The current review contains a critical assessment of these technologies in the context of recent advances in software and hardware in order to move microalgae production towards process automation through multivariate process control (MVPC) and software sensors trained on "big data". The paper will also include a comprehensive overview of off-line implementations of vibrational spectroscopy in microalgal research as it pertains to spectral interpretation and process automation to aid and motivate development.

  14. Evaluation of Simulated Marine Aerosol Production Using the WaveWatchIII Prognostic Wave Model Coupled to the Community Atmosphere Model within the Community Earth System Model

    Energy Technology Data Exchange (ETDEWEB)

    Long, M. S. [Harvard Univ., Cambridge, MA (United States). School of Engineering and Applied Sciences; Keene, William C. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Environmental Sciences; Zhang, J. [Univ. of North Dakota, Grand Forks, ND (United States). Dept. of Atmospheric Sciences; Reichl, B. [Univ. of Rhode Island, Narragansett, RI (United States). Graduate School of Oceanography; Shi, Y. [Univ. of North Dakota, Grand Forks, ND (United States). Dept. of Atmospheric Sciences; Hara, T. [Univ. of Rhode Island, Narragansett, RI (United States). Graduate School of Oceanography; Reid, J. S. [Naval Research Lab. (NRL), Monterey, CA (United States); Fox-Kemper, B. [Brown Univ., Providence, RI (United States). Earth, Environmental and Planetary Sciences; Craig, A. P. [National Center for Atmospheric Research, Boulder, CO (United States); Erickson, D. J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Division; Ginis, I. [Univ. of Rhode Island, Narragansett, RI (United States). Graduate School of Oceanography; Webb, A. [Univ. of Tokyo (Japan). Dept. of Ocean Technology, Policy, and Environment

    2016-11-08

    Primary marine aerosol (PMA) is emitted into the atmosphere via breaking wind waves on the ocean surface. Most parameterizations of PMA emissions use 10-meter wind speed as a proxy for wave action. This investigation coupled the 3rd generation prognostic WAVEWATCH-III wind-wave model within a coupled Earth system model (ESM) to drive PMA production using wave energy dissipation rate – analogous to whitecapping – in place of 10-meter wind speed. The wind speed parameterization did not capture basin-scale variability in relations between wind and wave fields. Overall, the wave parameterization did not improve comparison between simulated versus measured AOD or Na+, thus highlighting large remaining uncertainties in model physics. Results confirm the efficacy of prognostic wind-wave models for air-sea exchange studies coupled with laboratory- and field-based characterizations of the primary physical drivers of PMA production. No discernible correlations were evident between simulated PMA fields and observed chlorophyll or sea surface temperature.

  15. Community

    Science.gov (United States)

    stability Science & Innovation Collaboration Careers Community Environment Science & Innovation Recruitment Events Community Commitment Giving Campaigns, Drives Economic Development Employee Funded neighbor pledge: contribute to quality of life in Northern New Mexico through economic development

  16. Microalgal carbohydrates. An overview of the factors influencing carbohydrates production, and of main bioconversion technologies for production of biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Markou, Giorgos; Georgakakis, Dimitris [Agricultural Univ. of Athens (Greece). Dept. of Natural Resources Management and Agricultural Engineering; Angelidaki, Irini [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Environmental Engineering

    2012-11-15

    Microalgal biomass seems to be a promising feedstock for biofuel generation. Microalgae have relative high photosynthetic efficiencies, high growth rates, and some species can thrive in brackish water or seawater and wastewater from the food- and agro-industrial sector. Today, the main interest in research is the cultivation of microalgae for lipids production to generate biodiesel. However, there are several other biological or thermochemical conversion technologies, in which microalgal biomass could be used as substrate. However, the high protein content or the low carbohydrate content of the majority of the microalgal species might be a constraint for their possible use in these technologies. Moreover, in the majority of biomass conversion technologies, carbohydrates are the main substrate for production of biofuels. Nevertheless, microalgae biomass composition could be manipulated by several cultivation techniques, such as nutrient starvation or other stressed environmental conditions, which cause the microalgae to accumulate carbohydrates. This paper attempts to give a general overview of techniques that can be used for increasing the microalgal biomass carbohydrate content. In addition, biomass conversion technologies, related to the conversion of carbohydrates into biofuels are discussed. (orig.)

  17. Detailing the start-up and microalgal growth performance of a full-scale photobioreactor operated with bioindustrial wastewater

    DEFF Research Database (Denmark)

    Podevin, Michael Paul Ambrose; Fotidis, Ioannis; De Francisci, Davide

    2017-01-01

    were tested. Bioindustrial WW medium was treated with ultrafiltration and was demonstrated to be a viable microalgal growth medium at large scale; however, further treatment is needed for the removal of fecal coliform to meet drinking water standards. The fresh water mesophilic algae Chlorella...

  18. Enzymatic transesterification of microalgal oil from Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized Burkholderia lipase.

    Science.gov (United States)

    Tran, Dang-Thuan; Yeh, Kuei-Ling; Chen, Ching-Lung; Chang, Jo-Shu

    2012-03-01

    An indigenous microalga Chlorella vulgaris ESP-31 grown in an outdoor tubular photobioreactor with CO(2) aeration obtained a high oil content of up to 63.2%. The microalgal oil was then converted to biodiesel by enzymatic transesterification using an immobilized lipase originating from Burkholderia sp. C20. The conversion of the microalgae oil to biodiesel was conducted by transesterification of the extracted microalgal oil (M-I) and by transesterification directly using disrupted microalgal biomass (M-II). The results show that M-II achieved higher biodiesel conversion (97.3 wt% oil) than M-I (72.1 wt% oil). The immobilized lipase worked well when using wet microalgal biomass (up to 71% water content) as the oil substrate. The immobilized lipase also tolerated a high methanol to oil molar ratio (>67.93) when using the M-II approach, and can be repeatedly used for six cycles (or 288 h) without significant loss of its original activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Assessment of the performance of SMFCs in the bioremediation of PAHs in contaminated marine sediments under different redox conditions and analysis of the associated microbial communities

    KAUST Repository

    Hamdan, Hamdan Z.

    2016-10-09

    The biodegradation of naphthalene, 2-methylnaphthalene and phenanthrene was evaluated in marine sediment microbial fuel cells (SMFCs) under different biodegradation conditions, including sulfate reduction as a major biodegradation pathway, employment of anode as terminal electron acceptor (TEA) under inhibited sulfate reducing bacteria activity, and combined sulfate and anode usage as electron acceptors. A significant removal of naphthalene and 2-methylnaphthalene was observed at early stages of incubation in all treatments and was attributed to their high volatility. In the case of phenanthrene, a significant removal (93.83 ± 1.68%) was measured in the closed circuit SMFCs with the anode acting as the main TEA and under combined anode and sulfate reduction conditions (88.51 ± 1.3%). A much lower removal (40.37 ± 3.24%) was achieved in the open circuit SMFCs operating with sulfate reduction as a major biodegradation pathway. Analysis of the anodic bacterial community using 16S rRNA gene pyrosequencing revealed the enrichment of genera with potential exoelectrogenic capability, namely Geoalkalibacter and Desulfuromonas, on the anode of the closed circuit SMFCs under inhibited SRB activity, while they were not detected on the anode of open circuit SMFCs. These results demonstrate the role of the anode in enhancing PAHs biodegradation in contaminated marine sediments and suggest a higher system efficiency in the absence of competition between microbial redox processes (under SRB inhibition), namely due to the anode enrichment with exoelectrogenic bacteria, which is a more energetically favorable mechanism for PAHs oxidation than sulfate.

  20. Effect of different enrichment strategies on microbial community structure in petroleum-contaminated marine sediment in Dalian, China.

    Science.gov (United States)

    Chen, Chao; Liu, Qiu; Liu, Changjian; Yu, Jicheng

    2017-04-15

    An oil spill occurred at Xingang Port, Dalian, China in 2010. Four years after this spill, oil contamination was still detected in samples collected nearby. In this study, the strains that evolved in the sediment were screened by high-throughput sequencing technology. Most of these strains were genera reported to have functions associated with crude oil biodegradation. The diversities and numbers of microbes were monitored through enrichment culturing; the dominant strains propagated at first, but the enrichment could not be continued, which indicated that the prolonged culture was not effective in the enrichment of the micro-consortium. Oxygen was also observed to affect the propagation of the dominant microbes. The results showed the role of culture strategies and oxygen in the enrichment of the petroleum-degrading microbes. Therefore, dominant strains could be screened by optimizing both the enrichment time and oxygen concentration used for culturing to facilitate oil biodegradation in the marine ecosystem. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Integrated conservation and development: evaluating a community-based marine protected area project for equality of socioeconomic impacts

    Science.gov (United States)

    Gurney, Georgina G.; Pressey, Robert L.; Cinner, Joshua E.; Pollnac, Richard; Campbell, Stuart J.

    2015-01-01

    Despite the prevalence of protected areas, evidence of their impacts on people is weak and remains hotly contested in conservation policy. A key question in this debate is whether socioeconomic impacts vary according to social subgroup. Given that social inequity can create conflict and impede poverty reduction, understanding how protected areas differentially affect people is critical to designing them to achieve social and biological goals. Understanding heterogeneous responses to protected areas can improve targeting of management activities and help elucidate the pathways through which impacts of protected areas occur. Here, we assessed whether the socioeconomic impacts of marine protected areas (MPAs)—designed to achieve goals for both conservation and poverty alleviation—differed according to age, gender or religion in associated villages in North Sulawesi, Indonesia. Using data from pre-, mid- and post-implementation of the MPAs for control and project villages, we found little empirical evidence that impacts on five key socioeconomic indicators related to poverty differed according to social subgroup. We found suggestive empirical evidence that the effect of the MPAs on environmental knowledge differed by age and religion; over the medium and long terms, younger people and Muslims showed greater improvements compared with older people and Christians, respectively. PMID:26460130

  2. Integrated conservation and development: evaluating a community-based marine protected area project for equality of socioeconomic impacts.

    Science.gov (United States)

    Gurney, Georgina G; Pressey, Robert L; Cinner, Joshua E; Pollnac, Richard; Campbell, Stuart J

    2015-11-05

    Despite the prevalence of protected areas, evidence of their impacts on people is weak and remains hotly contested in conservation policy. A key question in this debate is whether socioeconomic impacts vary according to social subgroup. Given that social inequity can create conflict and impede poverty reduction, understanding how protected areas differentially affect people is critical to designing them to achieve social and biological goals. Understanding heterogeneous responses to protected areas can improve targeting of management activities and help elucidate the pathways through which impacts of protected areas occur. Here, we assessed whether the socioeconomic impacts of marine protected areas (MPAs)-designed to achieve goals for both conservation and poverty alleviation-differed according to age, gender or religion in associated villages in North Sulawesi, Indonesia. Using data from pre-, mid- and post-implementation of the MPAs for control and project villages, we found little empirical evidence that impacts on five key socioeconomic indicators related to poverty differed according to social subgroup. We found suggestive empirical evidence that the effect of the MPAs on environmental knowledge differed by age and religion; over the medium and long terms, younger people and Muslims showed greater improvements compared with older people and Christians, respectively. © 2015 The Author(s).

  3. Deep-sea faunal communities associated with a lost intermodal shipping container in the Monterey Bay National Marine Sanctuary, CA.

    Science.gov (United States)

    Taylor, Josi R; DeVogelaere, Andrew P; Burton, Erica J; Frey, Oren; Lundsten, Lonny; Kuhnz, Linda A; Whaling, P J; Lovera, Christopher; Buck, Kurt R; Barry, James P

    2014-06-15

    Carrying assorted cargo and covered with paints of varying toxicity, lost intermodal containers may take centuries to degrade on the deep seafloor. In June 2004, scientists from Monterey Bay Aquarium Research Institute (MBARI) discovered a recently lost container during a Remotely Operated Vehicle (ROV) dive on a sediment-covered seabed at 1281 m depth in Monterey Bay National Marine Sanctuary (MBNMS). The site was revisited by ROV in March 2011. Analyses of sediment samples and high-definition video indicate that faunal assemblages on the container's exterior and the seabed within 10 m of the container differed significantly from those up to 500 m. The container surface provides hard substratum for colonization by taxa typically found in rocky habitats. However, some key taxa that dominate rocky areas were absent or rare on the container, perhaps related to its potential toxicity or limited time for colonization and growth. Ecological effects appear to be restricted to the container surface and the benthos within ∼10 m. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Microbes on a bottle: substrate, season and geography influence community composition of microbes colonizing marine plastic debris

    OpenAIRE

    Carter, Dee A.; Oberbeckmann, Sonja; Osborn, A. Mark; Duhaime, Melissa B.

    2016-01-01

    Plastic debris pervades in our oceans and freshwater systems and the potential ecosystem-level impacts of this anthropogenic litter require urgent evaluation. Microbes readily colonize aquatic plastic debris and members of these biofilm communities are speculated to include pathogenic, toxic, invasive or plastic degrading-species. The influence of plastic-colonizing microorganisms on the fate of plastic debris is largely unknown, as is the role of plastic in selecting for unique microbial com...

  5. Individual to Community-Level Faunal Responses to Environmental Change from a Marine Fossil Record of Early Miocene Global Warming

    Science.gov (United States)

    Belanger, Christina L.

    2012-01-01

    Modern climate change has a strong potential to shift earth systems and biological communities into novel states that have no present-day analog, leaving ecologists with no observational basis to predict the likely biotic effects. Fossil records contain long time-series of past environmental changes outside the range of modern observation, which are vital for predicting future ecological responses, and are capable of (a) providing detailed information on rates of ecological change, (b) illuminating the environmental drivers of those changes, and (c) recording the effects of environmental change on individual physiological rates. Outcrops of Early Miocene Newport Member of the Astoria Formation (Oregon) provide one such time series. This record of benthic foraminiferal and molluscan community change from continental shelf depths spans a past interval environmental change (∼20.3-16.7 mya) during which the region warmed 2.1–4.5°C, surface productivity and benthic organic carbon flux increased, and benthic oxygenation decreased, perhaps driven by intensified upwelling as on the modern Oregon coast. The Newport Member record shows that (a) ecological responses to natural environmental change can be abrupt, (b) productivity can be the primary driver of faunal change during global warming, (c) molluscs had a threshold response to productivity change while foraminifera changed gradually, and (d) changes in bivalve body size and growth rates parallel changes in taxonomic composition at the community level, indicating that, either directly or indirectly through some other biological parameter, the physiological tolerances of species do influence community change. Ecological studies in modern and fossil records that consider multiple ecological levels, environmental parameters, and taxonomic groups can provide critical information for predicting future ecological change and evaluating species vulnerability. PMID:22558424

  6. A Study of Microalgal Symbiotic Communities with the Aim to Increase Biomass and Biodiesel Production

    DEFF Research Database (Denmark)

    Baggesen, Claus

    Microalgae are nearly everywhere and they are responsible for a large part of the world’s primaryproduction.Their ability to grow fast and toreach high cell densities makes them candidates for use in the production of biofuel. A key feature of many algae is the production of lipids as storage mol...

  7. Effect of the nutritional status of semi-continuous microalgal cultures on the productivity and biochemical composition of Brachionus plicatilis.

    Science.gov (United States)

    Ferreira, Martiña; Seixas, Pedro; Coutinho, Paula; Fábregas, Jaime; Otero, Ana

    2011-12-01

    The rotifer Brachionus plicatilis was cultured using the microalga Isochrysis aff. galbana clone T-ISO as feed. T-ISO was cultured semi-continuously with daily renewal rates of 10%, 20%, 30%, 40%, and 50% of the volume of cultures. The increase of renewal rate led to increasing nutrient and light availability in microalgal cultures, which caused differences in the biochemical composition of microalgal biomass. Growth rate, individual dry weight, organic content, and biomass productivity of rotifer cultures increased in response to higher growth rate in T-ISO cultures. Rotifer growth rate showed a strong negative correlation (R² = 0.90) with the C/N ratio of microalgal biomass. Rotifer dry weight was also affected by nutrient availability of T-ISO cultures, increasing up to 50% from nutrient-limited to nutrient-sufficient conditions. Consequently, biomass productivity of rotifer cultures increased more than twofold with the increase of renewal rate of T-ISO cultures. Rotifer organic content underwent the same trend of total dry weight. Maximum content of polyunsaturated fatty acids was reached in rotifers fed T-ISO from the renewal rate of 40%, with percentages of docosahexaenoic acid (22:6ω-3, DHA) and eicosapentaenoic acid (20:5ω-3, EPA) of 11% and 5% of total fatty acids, respectively. Selecting the most appropriate conditions for microalgal culture can therefore enhance the nutritive quality of microalgal biomass, resulting in a better performance of filter feeders and their nutrient content, and may constitute a useful tool to improve the rearing of fish larvae and other aquaculture organisms that require live feed in some or all the stages of their life cycle.

  8. Limited differences in fish and benthic communities and possible cascading effects inside and outside a protected marine area in Sagres (SW Portugal).

    Science.gov (United States)

    Gil Fernández, C; Paulo, D; Serrão, E A; Engelen, A H

    2016-03-01

    Marine protected areas (MPAs) are a relatively recent fisheries management and conservation tool for conservation of marine ecosystems and serve as experimental grounds to assess trophic cascade effects in areas were fishing is restricted to some extent. A series of descriptive field studies were performed to assess fish and benthic communities between two areas within a newly established MPA in SW Portugal. We characterized benthic macroalgal composition and determined the size, density and biomass of the main benthic predatory and herbivorous fish species as well as the main benthic herbivorous invertebrates to assess indications of top-down control on the phytobenthic assemblages. Fish species were identical inside and outside the MPA, in both cases Sarpa salpa was the most abundant fish herbivore and Diplodus spp. accounted for the great majority of the benthic predators. However, size and biomass of D. spp. were higher inside than outside the MPA. The main herbivorous invertebrate was the sea urchin Paracentrotus lividus, which was smaller and predominantly showing a crevice-dwelling behaviour in the MPA. In addition, P. lividus size frequency distribution showed a unimodal pattern outside and a bimodal pattern inside the MPA. We found significant differences in the algal assemblages between inside and outside the MPA, with higher abundance of turf and foliose algae inside, and articulated calcareous and corticated macrophytes outside the MPA, but no differences in the invasive Asparagopsis spp. The obtained results show differences in predatory fish and benthic community structure, but not in species richness, inside and outside the MPA. We hypothesize these differences lead to variation in species interactions: directly through predation and indirectly via affecting sea urchins behavioural patterns, predators might drive changes in macroalgal assemblages via trophic cascade in the study area. However due to non-biological differences between the two areas it

  9. Reef-fish larval dispersal patterns validate no-take marine reserve network connectivity that links human communities

    Science.gov (United States)

    Abesamis, Rene A.; Saenz-Agudelo, Pablo; Berumen, Michael L.; Bode, Michael; Jadloc, Claro Renato L.; Solera, Leilani A.; Villanoy, Cesar L.; Bernardo, Lawrence Patrick C.; Alcala, Angel C.; Russ, Garry R.

    2017-09-01

    Networks of no-take marine reserves (NTMRs) are a widely advocated strategy for managing coral reefs. However, uncertainty about the strength of population connectivity between individual reefs and NTMRs through larval dispersal remains a major obstacle to effective network design. In this study, larval dispersal among NTMRs and fishing grounds in the Philippines was inferred by conducting genetic parentage analysis on a coral-reef fish ( Chaetodon vagabundus). Adult and juvenile fish were sampled intensively in an area encompassing approximately 90 km of coastline. Thirty-seven true parent-offspring pairs were accepted after screening 1978 juveniles against 1387 adults. The data showed all types of dispersal connections that may occur in NTMR networks, with assignments suggesting connectivity among NTMRs and fishing grounds ( n = 35) far outnumbering those indicating self-recruitment ( n = 2). Critically, half (51%) of the inferred occurrences of larval dispersal linked reefs managed by separate, independent municipalities and constituent villages, emphasising the need for nested collaborative management arrangements across management units to sustain NTMR networks. Larval dispersal appeared to be influenced by wind-driven seasonal reversals in the direction of surface currents. The best-fit larval dispersal kernel estimated from the parentage data predicted that 50% of larvae originating from a population would attempt to settle within 33 km, and 95% within 83 km. Mean larval dispersal distance was estimated to be 36.5 km. These results suggest that creating a network of closely spaced (less than a few tens of km apart) NTMRs can enhance recruitment for protected and fished populations throughout the NTMR network. The findings underscore major challenges for regional coral-reef management initiatives that must be addressed with priority: (1) strengthening management of NTMR networks across political or customary boundaries; and (2) achieving adequate population

  10. Reef-fish larval dispersal patterns validate no-take marine reserve network connectivity that links human communities

    KAUST Repository

    Abesamis, Rene A.

    2017-03-24

    Networks of no-take marine reserves (NTMRs) are a widely advocated strategy for managing coral reefs. However, uncertainty about the strength of population connectivity between individual reefs and NTMRs through larval dispersal remains a major obstacle to effective network design. In this study, larval dispersal among NTMRs and fishing grounds in the Philippines was inferred by conducting genetic parentage analysis on a coral-reef fish (Chaetodon vagabundus). Adult and juvenile fish were sampled intensively in an area encompassing approximately 90 km of coastline. Thirty-seven true parent-offspring pairs were accepted after screening 1978 juveniles against 1387 adults. The data showed all types of dispersal connections that may occur in NTMR networks, with assignments suggesting connectivity among NTMRs and fishing grounds (n = 35) far outnumbering those indicating self-recruitment (n = 2). Critically, half (51%) of the inferred occurrences of larval dispersal linked reefs managed by separate, independent municipalities and constituent villages, emphasising the need for nested collaborative management arrangements across management units to sustain NTMR networks. Larval dispersal appeared to be influenced by wind-driven seasonal reversals in the direction of surface currents. The best-fit larval dispersal kernel estimated from the parentage data predicted that 50% of larvae originating from a population would attempt to settle within 33 km, and 95% within 83 km. Mean larval dispersal distance was estimated to be 36.5 km. These results suggest that creating a network of closely spaced (less than a few tens of km apart) NTMRs can enhance recruitment for protected and fished populations throughout the NTMR network. The findings underscore major challenges for regional coral-reef management initiatives that must be addressed with priority: (1) strengthening management of NTMR networks across political or customary boundaries; and (2) achieving adequate population

  11. Empowerment of the fishing community of Sesimbra through a participatory process: MARGov – collaborative governance in marine protected areas

    OpenAIRE

    Sá, Rita de Sousa Braga e

    2016-01-01

    Tese de doutoramento, Ciências do Mar, da Terra e do Ambiente, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016 Sesimbra is a community established in the largest valley of the Arrábida coast. It is deeply connected to the sea through fishing, shipbuilding, sailors which contributed to the Portuguese expansion (XV and XVI centuries), as well as being an important maritime route and a trade point. More recently tourism became an important activity. During the 40’s (XX centu...

  12. On diel variability of marine sediment backscattering properties caused by microphytobenthos photosynthesis: Impact of environmental factors

    Science.gov (United States)

    Gorska, Natalia; Kowalska-Duda, Ewa; Pniewski, Filip; Latała, Adam

    2018-06-01

    The study has been motivated by the development of the hydroacoustic techniques for mapping and classifying the benthic habitats and for the research of the microbenthos photosynthesis in the semi-enclosed Baltic Sea, particularly sensitive to human activity. The investigation of the effect of the benthic microalgal photosynthesis on the echo signal from the Baltic sandy sediments is continuing. The study clarifies the impact of the abiotic and biotic factors on the diel variation of the backscattering caused by the benthic microalgal photosynthetic activity. Five multiday laboratory experiments, different in hydrophysical or biological conditions, were conducted. During each measurement series, the "day" (illumination) and "night" (darkness) conditions (L:D cycle) were simulated and the diel variations of the echo energy of the backscattered signal were analyzed. The hydroacoustic data were acquired along with measuring biological and biooptical parameters and oxygen concentration. The study demonstrated the impact of microphytobenthos photosynthesis on the backscattering properties of the marine sediment which is sensitive to the illumination level, benthic microalgal biomass and macrozoobenthos bioturbation.

  13. Marine ecology

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Studies on marine ecology included marine pollution; distribution patterns of Pu and Am in the marine waters, sediments, and organisms of Bikini Atoll and the influence of physical, chemical, and biological factors on their movements through marine biogeochemical systems; transfer and dispersion of organic pollutants from an oil refinery through coastal waters; transfer of particulate pollutants, including sediments dispersed during construction of offshore power plants; and raft culture of the mangrove oysters

  14. A comparative study of microbial diversity and community structure in marine sediments using poly(A tailing and reverse transcription PCR

    Directory of Open Access Journals (Sweden)

    Tatsuhiko eHoshino

    2013-06-01

    Full Text Available To obtain a better understanding of metabolically active microbial communities, we tested a molecular ecological approach using poly(A tailing of environmental 16S rRNA, followed by full-length complementary DNA (cDNA synthesis and sequencing to eliminate potential biases caused by mismatching of PCR primer sequences. The RNA pool tested was extracted from marine sediments of the Yonaguni Knoll IV hydrothermal field in the southern Okinawa Trough. The sequences obtained using the ploy(A tailing method were compared statistically and phylogenetically with those obtained using conventional reverse transcription-polymerase chain reaction (RT-PCR with published domain-specific primers. Both methods indicated that Deltaproteobacteria are predominant in sediment (>85% of the total sequence read. The poly(A tailing method indicated that Desulfobacterales were the predominant deltaproteobacteria, while most of the sequences in libraries constructed using RT-PCR were derived from Desulfuromonadales. This discrepancy may have been due to low coverage of Desulfobacterales by the primers used. A comparison of library diversity indices indicated that the poly(A tailing method retrieves more phylogenetically diverse sequences from the environment. The four archaeal 16S rRNA sequences that were obtained using the poly(A tailing method formed deeply branching lineages that were related to Candidatus Parvarchaeum and the Ancient Archaeal Group. These results clearly demonstrate that poly(A tailing followed by cDNA sequencing is a powerful and less biased molecular ecological approach for the study of metabolically active microbial communities.

  15. Marine pollution

    International Nuclear Information System (INIS)

    Albaiges, J.

    1989-01-01

    This book covers the following topics: Transport of marine pollutants; Transformation of pollutants in the marine environment; Biological effects of marine pollutants; Sources and transport of oil pollutants in the Persian Gulf; Trace metals and hydrocarbons in Syrian coastal waters; and Techniques for analysis of trace pollutants

  16. Community.

    Science.gov (United States)

    Grauer, Kit, Ed.

    1995-01-01

    Art in context of community is the theme of this newsletter. The theme is introduced in an editorial "Community-Enlarging the Definition" (Kit Grauer). Related articles include: (1) "The Children's Bridge is not Destroyed: Heart in the Middle of the World" (Emil Robert Tanay); (2) "Making Bridges: The Sock Doll…

  17. Reduction of environmental and energy footprint of microalgal biodiesel production through material and energy integration.

    Science.gov (United States)

    Chowdhury, Raja; Viamajala, Sridhar; Gerlach, Robin

    2012-03-01

    The life cycle impacts were assessed for an integrated microalgal biodiesel production system that facilitates energy- and nutrient- recovery through anaerobic digestion, and utilizes glycerol generated within the facility for additional heterotrophic biodiesel production. Results show that when external fossil energy inputs are lowered through process integration, the energy demand, global warming potential (GWP), and process water demand decrease significantly and become less sensitive to algal lipid content. When substitution allocation is used to assign additional credit for avoidance of fossil energy use (through utilization of recycled nutrients and biogas), GWP and water demand can, in fact, increase with increase in lipid content. Relative to stand-alone algal biofuel facilities, energy demand can be lowered by 3-14 GJ per ton of biodiesel through process integration. GWP of biodiesel from the integrated system can be lowered by up to 71% compared to petroleum fuel. Evaporative water loss was the primary water demand driver. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Effect of nitrogen regime on microalgal lipid production during mixotrophic growth with glycerol.

    Science.gov (United States)

    Paranjape, Kiran; Leite, Gustavo B; Hallenbeck, Patrick C

    2016-08-01

    Mixotrophic growth of microalgae to boost lipid production is currently under active investigation. Such a process could be of practical importance if a cheap source of organic carbon, such as waste glycerol from biodiesel production, could be used. Several previous studies have already demonstrated that this carbon source can be used by different indigenous strains of microalgae. In this study it is shown that different nitrogen limitation strategies can be applied to further increase lipid production during growth with glycerol. In one strategy, cultures were grown in nitrogen replete medium and then resuspended in nitrogen free medium. In a second strategy, cultures were grown with different initial concentrations of nitrate. Lipid production by the two microalgal strains used, Chlorella sorokiniana (PCH02) and Chlorella vulgaris (PCH05), was shown to be boosted by strategies of nitrogen limitation, but they responded differently to how nitrogen limitation was imposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Three-Dimensional Simulation of Ultrasound-Induced Microalgal Cell Disruption.

    Science.gov (United States)

    Wang, M; Yuan, W; Hale, Andy

    2016-03-01

    The three-dimensional distribution (x, y, and z) of ultrasound-induced microalgal cell disruption in a sonochemical reactor was predicted by solving the Helmholtz equation using a three-dimensional acoustic module in the COMSOL Multiphysics software. The simulated local ultrasound pressure at any given location (x, y, and z) was found to correlate with cell disruption of a freshwater alga, Scenedesmus dimorphus, represented by the change of algal cell particle/debris concentration, chlorophyll-a fluorescence density (CAFD), and Nile red stained lipid fluorescence density (LFD), which was also validated by the model reaction of potassium iodide oxidation (the Weissler reaction). Furthermore, the effect of ultrasound power intensity and processing duration on algal cell disruption was examined to address the limitation of the model.

  20. Biodiesel production by direct transesterification of microalgal biomass with co-solvent.

    Science.gov (United States)

    Zhang, Yan; Li, Ya; Zhang, Xu; Tan, Tianwei

    2015-11-01

    In this study, a direct transesterification process using 75% ethanol and co-solvent was studied to reduce the energy consumption of lipid extraction process and improve the conversion yield of the microalgae biodiesel. The addition of a certain amount of co-solvent (n-hexane is most preferable) was required for the direct transesterification of microalgae biomass. With the optimal reaction condition of n-hexane to 75% ethanol volume ratio 1:2, mixed solvent dosage 6.0mL, reaction temperature 90°C, reaction time 2.0h and catalyst volume 0.6mL, the direct transesterification process of microalgal biomass resulted in a high conversion yield up to 90.02±0.55wt.%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Marine genomics

    DEFF Research Database (Denmark)

    Oliveira Ribeiro, Ângela Maria; Foote, Andrew David; Kupczok, Anne

    2017-01-01

    Marine ecosystems occupy 71% of the surface of our planet, yet we know little about their diversity. Although the inventory of species is continually increasing, as registered by the Census of Marine Life program, only about 10% of the estimated two million marine species are known. This lag......-throughput sequencing approaches have been helping to improve our knowledge of marine biodiversity, from the rich microbial biota that forms the base of the tree of life to a wealth of plant and animal species. In this review, we present an overview of the applications of genomics to the study of marine life, from...

  2. A novel one-stage cultivation/fermentation strategy for improved biogas production with microalgal biomass.

    Science.gov (United States)

    Klassen, Viktor; Blifernez-Klassen, Olga; Hoekzema, Yoep; Mussgnug, Jan H; Kruse, Olaf

    2015-12-10

    The use of alga biomass for biogas generation has been studied for over fifty years but until today, several distinct features, like inefficient degradation and low C/N ratios, limit the applicability of algal biomass for biogas production in larger scale. In this work we investigated a novel, one-stage combined cultivation/fermentation strategy including inherently progressing nitrogen starvation conditions to generate improved microalgal biomass substrates. For this strategy, comparable low amounts of nitrogen fertilizers were applied during cultivation and no additional enzymatic, chemical or physical pretreatments had to be performed. The results of this study demonstrate that progressing nitrogen limitation leads to continuously increasing C/N ratios of the biomass up to levels of 24-26 for all three tested alga strains (Chlamydomonas reinhardtii, Parachlorella kessleri and Scenedesmus obliquus). Importantly, the degradation efficiency of the algal cells increased with progressing starvation, leading to strain-specific cell disintegration efficiencies of 35%-100% during the fermentation process. Nitrogen limitation treatment resulted in a 65% increase of biogas yields for C. reinhardtii biomass (max. 698±23mL biogas g(-1) VS) when compared to replete conditions. For P. kessleri and S. obliquus, yields increased by 94% and 106% (max. 706±39mL and 586±36mL biogas g(-1) VS, respectively). From these results we conclude that this novel one-stage cultivation strategy with inherent nitrogen limitation can be used as a pretreatment for microalgal biomass generation, in order to produce accessible substrates with optimized C/N ratios for the subsequent anaerobic fermentation process, thus increasing methane production and avoiding the risk of ammonia inhibition effects within the fermenter. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. The Development of Coastal and Marine

    Directory of Open Access Journals (Sweden)

    Suharto Widjojo

    2004-01-01

    Full Text Available Planning and development process of oastaland marine resources tends centralized and adopted top down policy, without any active participations from coastal and marine communities. In order to reach integrated and sustainable development in coastaland marine areas, people should have both complete and up to date information, so that planning and decision making for all aspect of the environment can be done easily. People should give a high attention of surveis, mappings, as well as science and technology of coastal and marine sectors, in order to change the paradigm of development from inland to coastal and marine. Moreover, people should give high attention of potential resources of coastal and marine areas.

  4. Interactions between polystyrene microplastics and marine phytoplankton lead to species-specific hetero-aggregation.

    Science.gov (United States)

    Long, Marc; Paul-Pont, Ika; Hégaret, Hélène; Moriceau, Brivaela; Lambert, Christophe; Huvet, Arnaud; Soudant, Philippe

    2017-09-01

    To understand the fate and impacts of microplastics (MP) in the marine ecosystems, it is essential to investigate their interactions with phytoplankton as these may affect MP bioavailability to marine organisms as well as their fate in the water column. However, the behaviour of MP with marine phytoplanktonic cells remains little studied and thus unpredictable. The present study assessed the potential for phytoplankton cells to form hetero-aggregates with small micro-polystyrene (micro-PS) particles depending on microalgal species and physiological status. A prymnesiophycea, Tisochrysis lutea, a dinoflagellate, Heterocapsa triquetra, and a diatom, Chaetoceros neogracile, were exposed to micro-PS (2 μm diameter; 3.96 μg L -1 ) during their growth culture cycles. Micro-PS were quantified using an innovative flow-cytometry approach, which allowed the monitoring of the micro-PS repartition in microalgal cultures and the distinction between free suspended micro-PS and hetero-aggregates of micro-PS and microalgae. Hetero-aggregation was observed for C. neogracile during the stationary growth phase. The highest levels of micro-PS were "lost" from solution, sticking to flasks, with T. lutea and H. triquetra cultures. This loss of micro-PS sticking to the flask walls increased with the age of the culture for both species. No effects of micro-PS were observed on microalgal physiology in terms of growth and chlorophyll fluorescence. Overall, these results highlight the potential for single phytoplankton cells and residual organic matter to interact with microplastics, and thus potentially influence their distribution and bioavailability in experimental systems and the water column. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Marine ecosystem community carbon and nutrient uptake stoichiometry under varying ocean acidification during the PeECE III experiment

    Directory of Open Access Journals (Sweden)

    R. G. J. Bellerby

    2008-11-01

    Full Text Available Changes to seawater inorganic carbon and nutrient concentrations in response to the deliberate CO2 perturbation of natural plankton assemblages were studied during the 2005 Pelagic Ecosystem CO2 Enrichment (PeECE III experiment. Inverse analysis of the temporal inorganic carbon dioxide system and nutrient variations was used to determine the net community stoichiometric uptake characteristics of a natural pelagic ecosystem perturbed over a range of pCO2 scenarios (350, 700 and 1050 μatm. Nutrient uptake showed no sensitivity to CO2 treatment. There was enhanced carbon production relative to nutrient consumption in the higher CO2 treatments which was positively correlated with the initial CO2 concentration. There was no significant calcification response to changing CO2 in Emiliania huxleyi by the peak of the bloom and all treatments exhibited low particulate inorganic carbon production (~15 μmol kg−1. With insignificant air-sea CO2 exchange across the treatments, the enhanced carbon uptake was due to increase organic carbon production. The inferred cumulative C:N:P stoichiometry of organic production increased with CO2 treatment from 1:6.3:121 to 1:7.1:144 to 1:8.25:168 at the height of the bloom. This study discusses how ocean acidification may incur modification to the stoichiometry of pelagic production and have consequences for ocean biogeochemical cycling.

  6. Molasses wastewater treatment and lipid production at low temperature conditions by a microalgal mutant Scenedesmus sp. Z-4

    OpenAIRE

    Ma, Chao; Wen, Hanquan; Xing, Defeng; Pei, Xuanyuan; Zhu, Jiani; Ren, Nanqi; Liu, Bingfeng

    2017-01-01

    Background Simultaneous wastewater treatment and lipid production by oleaginous microalgae show great potential to alleviate energy shortage and environmental pollution, because they exhibit tremendous advantages over traditional activated sludge. Currently, most research on wastewater treatment by microalgal are carried out at optimized temperature conditions (25?35??C), but no information about simultaneous wastewater treatment and lipid production by microalgae at low temperatures has been...

  7. Simultaneous improvement in production of microalgal biodiesel and high-value alpha-linolenic acid by a single regulator acetylcholine

    OpenAIRE

    Parsaeimehr, Ali; Sun, Zhilan; Dou, Xiao; Chen, Yi-Feng

    2015-01-01

    Background Photoautotrophic microalgae are a promising avenue for sustained biodiesel production, but are compromised by low yields of biomass and lipids at present. We are developing a chemical approach to improve microalgal accumulation of feedstock lipids as well as high-value alpha-linolenic acid which in turn might provide a driving force for biodiesel production. Results We demonstrate the effectiveness of the small bioactive molecule ?acetylcholine? on accumulation of biomass, total li...

  8. Two-step microalgal biodiesel production using acidic catalyst generated from pyrolysis-derived bio-char

    International Nuclear Information System (INIS)

    Dong, Tao; Gao, Difeng; Miao, Chao; Yu, Xiaochen; Degan, Charles; Garcia-Pérez, Manuel; Rasco, Barbara; Sablani, Shyam S.; Chen, Shulin

    2015-01-01

    Highlights: • Highly active catalyst was prepared using bio-char co-produced in Auger pyrolysis. • Catalyst inhibitors in crude oil were effectively removed by a practical refinery process. • Free fatty acids (FFA) content in refined microalgal oil was reduced to less than 0.5%. • A total fatty acid methyl ester (FAME) yield of 99% was obtained via a two-step process. • The inexpensive bio-char catalyst is superior to Amberlyst-15 in pre-esterification. - Abstract: An efficient process for biodiesel production from fast-refined microalgal oil was demonstrated. A low cost catalyst prepared from pyrolysis-derived bio-char, was applied in pre-esterification to reduce free fatty acid (FFA) content. Results showed that the bio-char catalyst was highly active in esterification; however, the performance of the catalyst significantly reduced when crude microalgal oil was used as feedstock. To solve the problem caused by catalyst-fouling, a fast and scalable crude oil refinery procedure was carried out to remove chlorophyll and phospholipids that might degrade the catalyst and the quality of biodiesel. The activity and reusability of bio-char catalyst were remarkably improved in the fast-refined oil. FFA content in the refined microalgal oil was reduced to less than 0.5% after pre-esterification. The bio-char catalyst could be reused for 10 cycles without dramatic loss in activity. The pre-esterification fits the first-order kinetic reaction with activation energy of 42.16 kJ/mol. The activity of bio-char catalyst was superior to commercial Amberlyst-15 under the same reaction condition. A total fatty acid methyl ester (FAME, namely biodiesel) yield of 99% was obtained following the second-step CaO-catalyzed transesterification. The cost-effective bio-char catalyst has great potential for biodiesel production using feedstocks having high FFA content.

  9. Biodiversity, Community and Trophic Structure of the Suprabenthos of the Gulf of Cádiz-Guadalquivir Estuary Coupled System: Linking Pelagic-Benthic and Terrestrial-Marine Ecosystems.

    Science.gov (United States)

    Vilas, C.

    2016-02-01

    Suprabenthos biodiversity and species densities on both offshore and coastal systems are largely unknown. Main components like mysids, euphasiids or amphipods are omnivorous and constitute a major dietary component for many benthic and pelagic fishes, mammals, cephalopods and decapods. Despite their relevant ecological role linking pelagic-benthic food webs, suprabenthos have been chronically undersampled and their components underrepresented and underestimated in food web models. Many pelagic and demersal species of high commercial and ecological interest at the Gulf of Cádiz (GoC) feed at a bottom scattering layer identified from 0 to 200 m depth and up to 50 km from coast, related to the Guadalquivir Estuary (GE) influence coastal area, and present life history cycles based on a sequential use of habitats from GoC to GE nursery area, may be adapted to match the horizontal migrations of key suprabenthos prey species. In order to understand the ecological mechanisms through which the GE-GoC coupled ecosystem would influence the recruitment of these fishery resources, the suprabenthos was sampled by suprabenthic sldege (200 μm) from the shallow estuary to 75 m depth during June, August and November of 2013. We identified up to 300 species (H index 0.4-2-9 and Beta diversity 0.55), being copepods, molluscs, cumacea, cladocera, poliquets, decapods, mysids and amphipods the most important groups by biomass (mg/m3), finding densities up to 32.9 mg/m3 for copepods, 6 for mysids and up to 100 mg/m3 for decapods. Multivariate analysis determines depth as the most important variable explaining community structure, decreasing biodiversity with depth, while for sites at depths species show seasonal horizontal migrations between GoC and GE, connecting terrestrial and marine ecosystems.

  10. Marine biology

    International Nuclear Information System (INIS)

    Thurman, H.V.; Webber, H.H.

    1984-01-01

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index

  11. Action Spectra of Microalgal Photosynthesis and Depth Distribution of Spectral Scalar Irradiance in a Coastal Marine Sediment of Limfjorden, Denmark

    DEFF Research Database (Denmark)

    PLOUG, H.; LASSEN, C.; JØRGENSEN, BB

    1993-01-01

    for photosynthesis and spectral scalar irradiance, E0, were measured directly in the sediment at a spatial resolution of 0.1 mm by the use of oxygen and light microsensors. The action spectrum for the diatoms was similar to the attenuation spectrum of the scalar irradiance, K0, in the diatom layer with Chl...... to calculate the spectral quality for photosynthesis of the 400-700 nm light to which the two populations were exposed. This spectral quality was compared to that of the light incident on the sediment surface. Due to preferential extinction of wavelengths, at which their photosynthetically active pigments had...... populations, and that total light intensity and the chemical microenvironment are probably more important factors....

  12. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high ... or by any means without permission in writing from the copyright holder. ..... Journal of Chemical Engineering Research and Design 82 ... Indian Ocean Marine Science Association Technical.

  13. Marine Biomedicine

    Science.gov (United States)

    Bang, Frederik B.

    1977-01-01

    Describes early scientific research involving marine invertebrate pathologic processes that may have led to new insights into human disease. Discussed are inquiries of Metchnikoff, Loeb, and Cantacuzene (immunolgic responses in sea stars, horseshoe crabs, and marine worms, respectively). Describes current research stemming from these early…

  14. Marine Biology

    Science.gov (United States)

    Dewees, Christopher M.; Hooper, Jon K.

    1976-01-01

    A variety of informational material for a course in marine biology or oceanology at the secondary level is presented. Among the topics discussed are: food webs and pyramids, planktonic blooms, marine life, plankton nets, food chains, phytoplankton, zooplankton, larval plankton and filter feeders. (BT)

  15. Assessment of the performance of SMFCs in the bioremediation of PAHs in contaminated marine sediments under different redox conditions and analysis of the associated microbial communities

    KAUST Repository

    Hamdan, Hamdan Z.; Salam, Darine A.; Rao, Hari Ananda; Semerjian, Lucy; Saikaly, Pascal

    2016-01-01

    The biodegradation of naphthalene, 2-methylnaphthalene and phenanthrene was evaluated in marine sediment microbial fuel cells (SMFCs) under different biodegradation conditions, including sulfate reduction as a major biodegradation pathway

  16. An Evaluation of Marine Boundary Layer Cloud Property Simulations in the Community Atmosphere Model Using Satellite Observations: Conventional Subgrid Parameterization versus CLUBB

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hua [Joint Center for Earth Systems Technology, University of Maryland, Baltimore County, Baltimore, Maryland; Zhang, Zhibo [Joint Center for Earth Systems Technology, and Physics Department, University of Maryland, Baltimore County, Baltimore, Maryland; Ma, Po-Lun [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington; Ghan, Steven J. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, Washington; Wang, Minghuai [Institute for Climate and Global Change Research, and School of Atmospheric Sciences, Nanjing University, Nanjing, China

    2018-03-01

    This paper presents a two-step evaluation of the marine boundary layer (MBL) cloud properties from two Community Atmospheric Model (version 5.3, CAM5) simulations, one based on the CAM5 standard parameterization schemes (CAM5-Base), and the other on the Cloud Layers Unified By Binormals (CLUBB) scheme (CAM5-CLUBB). In the first step, we compare the cloud properties directly from model outputs between the two simulations. We find that the CAM5-CLUBB run produces more MBL clouds in the tropical and subtropical large-scale descending regions. Moreover, the stratocumulus (Sc) to cumulus (Cu) cloud regime transition is much smoother in CAM5-CLUBB than in CAM5-Base. In addition, in CAM5-Base we find some grid cells with very small low cloud fraction (<20%) to have very high in-cloud water content (mixing ratio up to 400mg/kg). We find no such grid cells in the CAM5-CLUBB run. However, we also note that both simulations, especially CAM5-CLUBB, produce a significant amount of “empty” low cloud cells with significant cloud fraction (up to 70%) and near-zero in-cloud water content. In the second step, we use satellite observations from CERES, MODIS and CloudSat to evaluate the simulated MBL cloud properties by employing the COSP satellite simulators. We note that a feature of the COSP-MODIS simulator to mimic the minimum detection threshold of MODIS cloud masking removes much more low clouds from CAM5-CLUBB than it does from CAM5-Base. This leads to a surprising result — in the large-scale descending regions CAM5-CLUBB has a smaller COSP-MODIS cloud fraction and weaker shortwave cloud radiative forcing than CAM5-Base. A sensitivity study suggests that this is because CAM5-CLUBB suffers more from the above-mentioned “empty” clouds issue than CAM5-Base. The COSP-MODIS cloud droplet effective radius in CAM5-CLUBB shows a spatial increase from coastal St toward Cu, which is in qualitative agreement with MODIS observations. In contrast, COSP-MODIS cloud droplet

  17. An assessment of natural product discovery from marine (sensu strictu) and marine-derived fungi

    Science.gov (United States)

    Overy, David P.; Bayman, Paul; Kerr, Russell G.; Bills, Gerald F.

    2014-01-01

    The natural products community has been investigating secondary metabolites from marine fungi for several decades, but when one attempts to search for validated reports of new natural products from marine fungi, one encounters a literature saturated with reports from ‘marine-derived’ fungi. Of the 1000+ metabolites that have been characterized to date, only approximately 80 of these have been isolated from species from exclusively marine lineages. These metabolites are summarized here along with the lifestyle and habitats of their producing organisms. Furthermore, we address some of the reasons for the apparent disconnect between the stated objectives of discovering new chemistry from marine organisms and the apparent neglect of the truly exceptional obligate marine fungi. We also offer suggestions on how to reinvigorate enthusiasm for marine natural products discovery from fungi from exclusive marine lineages and highlight the need for critically assessing the role of apparently terrestrial fungi in the marine environment. PMID:25379338

  18. Anaerobic co-digestion of coffee husks and microalgal biomass after thermal hydrolysis.

    Science.gov (United States)

    Passos, Fabiana; Cordeiro, Paulo Henrique Miranda; Baeta, Bruno Eduardo Lobo; de Aquino, Sergio Francisco; Perez-Elvira, Sara Isabel

    2018-04-01

    Residual coffee husks after seed processing may be better profited if bioconverted into energy through anaerobic digestion. This process may be improved by implementing a pretreatment step and by co-digesting the coffee husks with a more liquid biomass. In this context, this study aimed at evaluating the anaerobic co-digestion of coffee husks with microalgal biomass. For this, both substrates were pretreated separately and in a mixture for attaining 15% of total solids (TS), which was demonstrated to be the minimum solid content for pretreatment of coffee husks. The results showed that the anaerobic co-digestion presented a synergistic effect, leading to 17% higher methane yield compared to the theoretical value of both substrates biodegraded separately. Furthermore, thermal hydrolysis pretreatment increased coffee husks anaerobic biodegradability. For co-digestion trials, the highest values were reached for pretreatment at 120 °C for 60 min, which led to 196 mLCH 4 /gVS and maximum methane production rate of 0.38 d -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Dynamic metabolic modeling of heterotrophic and mixotrophic microalgal growth on fermentative wastes.

    Directory of Open Access Journals (Sweden)

    Caroline Baroukh

    2017-06-01

    Full Text Available Microalgae are promising microorganisms for the production of numerous molecules of interest, such as pigments, proteins or triglycerides that can be turned into biofuels. Heterotrophic or mixotrophic growth on fermentative wastes represents an interesting approach to achieving higher biomass concentrations, while reducing cost and improving the environmental footprint. Fermentative wastes generally consist of a blend of diverse molecules and it is thus crucial to understand microalgal metabolism in such conditions, where switching between substrates might occur. Metabolic modeling has proven to be an efficient tool for understanding metabolism and guiding the optimization of biomass or target molecule production. Here, we focused on the metabolism of Chlorella sorokiniana growing heterotrophically and mixotrophically on acetate and butyrate. The metabolism was represented by 172 metabolic reactions. The DRUM modeling framework with a mildly relaxed quasi-steady-state assumption was used to account for the switching between substrates and the presence of light. Nine experiments were used to calibrate the model and nine experiments for the validation. The model efficiently predicted the experimental data, including the transient behavior during heterotrophic, autotrophic, mixotrophic and diauxic growth. It shows that an accurate model of metabolism can now be constructed, even in dynamic conditions, with the presence of several carbon substrates. It also opens new perspectives for the heterotrophic and mixotrophic use of microalgae, especially for biofuel production from wastes.

  20. Composition and Quantitation of Microalgal Lipids by ERETIC 1H NMR Method

    Directory of Open Access Journals (Sweden)

    Angelo Fontana

    2013-09-01

    Full Text Available Accurate characterization of biomass constituents is a crucial aspect of research in the biotechnological application of natural products. Here we report an efficient, fast and reproducible method for the identification and quantitation of fatty acids and complex lipids (triacylglycerols, glycolipids, phospholipids in microalgae under investigation for the development of functional health products (probiotics, food ingredients, drugs, etc. or third generation biofuels. The procedure consists of extraction of the biological matrix by modified Folch method and direct analysis of the resulting material by proton nuclear magnetic resonance (1H NMR. The protocol uses a reference electronic signal as external standard (ERETIC method and allows assessment of total lipid content, saturation degree and class distribution in both high throughput screening of algal collection and metabolic analysis during genetic or culturing studies. As proof of concept, the methodology was applied to the analysis of three microalgal species (Thalassiosira weissflogii, Cyclotella cryptica and Nannochloropsis salina which drastically differ for the qualitative and quantitative composition of their fatty acid-based lipids.

  1. Biotechnological Screening of Microalgal and Cyanobacterial Strains for Biogas Production and Antibacterial and Antifungal Effects

    Directory of Open Access Journals (Sweden)

    Opayi Mudimu

    2014-05-01

    Full Text Available Microalgae and cyanobacteria represent a valuable natural resource for the generation of a large variety of chemical substances that are of interest for medical research, can be used as additives in cosmetics and food production, or as an energy source in biogas plants. The variety of potential agents and the use of microalgae and cyanobacteria biomass for the production of these substances are little investigated and not exploited for the market. Due to the enormous biodiversity of microalgae and cyanobacteria, they hold great promise for novel products. In this study, we investigated a large number of microalgal and cyanobacterial strains from the Culture Collection of Algae at Göttingen University (SAG with regard to their biomass and biogas production, as well antibacterial and antifungal effects. Our results demonstrated that microalgae and cyanobacteria are able to generate a large number of economically-interesting substances in different quantities dependent on strain type. The distribution and quantity of some of these components were found to reflect phylogenetic relationships at the level of classes. In addition, between closely related species and even among multiple isolates of the same species, the productivity may be rather variable.

  2. A simple method for decomposition of peracetic acid in a microalgal cultivation system.

    Science.gov (United States)

    Sung, Min-Gyu; Lee, Hansol; Nam, Kibok; Rexroth, Sascha; Rögner, Matthias; Kwon, Jong-Hee; Yang, Ji-Won

    2015-03-01

    A cost-efficient process devoid of several washing steps was developed, which is related to direct cultivation following the decomposition of the sterilizer. Peracetic acid (PAA) is known to be an efficient antimicrobial agent due to its high oxidizing potential. Sterilization by 2 mM PAA demands at least 1 h incubation time for an effective disinfection. Direct degradation of PAA was demonstrated by utilizing components in conventional algal medium. Consequently, ferric ion and pH buffer (HEPES) showed a synergetic effect for the decomposition of PAA within 6 h. On the contrary, NaNO3, one of the main components in algal media, inhibits the decomposition of PAA. The improved growth of Chlorella vulgaris and Synechocystis PCC6803 was observed in the prepared BG11 by decomposition of PAA. This process involving sterilization and decomposition of PAA should help cost-efficient management of photobioreactors in a large scale for the production of value-added products and biofuels from microalgal biomass.

  3. Application of Fungicides and Microalgal Phenolic Extracts for the Direct Control of Fumonisin Contamination in Maize.

    Science.gov (United States)

    Scaglioni, Priscila Tessmer; Blandino, Massimo; Scarpino, Valentina; Giordano, Debora; Testa, Giulio; Badiale-Furlong, Eliana

    2018-05-16

    Fungicides and, for the first time, microalgal phenolic extracts (MPE) from Spirulina sp. and Nannochloropsis sp. were applied on maize culture media under field conditions to evaluate their ability to minimize Fusarium species development and fumonisin production. An in vitro assay against F. verticillioides was carried out using maize grains as the culture medium. An open-field experiment was carried out in Northwest Italy under natural infection conditions. The compared treatments were factorial combinations of two insecticide treatments (an untreated control and pyrethroid, used against European Corn Borer), four antifungal treatments (an untreated control, MPE from Spirulina sp., MPE from Nannochloropsis sp., and a synthetic fungicide), and two timings of the application of the antifungal compounds (at maize flowering and at the milk stage). The MPE compounds were capable of inhibiting fumonisin production in vitro more efficiently than tebuconazole. Insecticide application reduced the infection by Fusarium species and subsequent fumonisin contamination. However, fumonisins in maize fields were not significantly controlled by either fungicide or MPE application.

  4. Bioremoval Capacity Of Phenol By Green Micro-Algal And Fungal Species Isolated From Dry Environment

    Directory of Open Access Journals (Sweden)

    Abdullah T. Al-fawwaz

    2015-08-01

    Full Text Available Phenol is an organic hazardous pollutant that exerts toxic effects on living cells at relatively at low concentrations. Moreover accumulation of phenol exhibit toxicity towards the biotic components of the environment. Phenol bioremoval is a very useful approach to clean up the residual phenol from the environment. This study aims at isolating green microalgae and fungi from local dry environment to test their ability to remove phenol. Subsequently two green microalgal species have been isolated and identified as Desmodesmus sp. and Chlamydomonas sp.. Also two fungal species have been isolated and identified as Rhizopus sp. and Mucor sp. Phenol bioremoval capacity as well as the effects of some physicochemical factors on the bioremoval process were then studied. These factors include initial phenol concentration contact time and the synergistic effect Desmodesmus sp. and Rhizopus sp. on the bioremoval process. Both microalgae and fungi showed phenol bioremoval capacity. The highest phenol removal percentage among algae was found 75 by Desmodesmus sp. after 25 days at 25 mgL while the highest phenol removal percentage among fungi was found 86 by Rhizopus sp. after 25 days at 100 mgL. Bioremoval of phenol by the consortium Desmodesmus sp. and Rhizopus sp. was found to be 95 at the phenol concentration 25 mgL.

  5. Chemicals to enhance microalgal growth and accumulation of high-value bioproducts

    Directory of Open Access Journals (Sweden)

    Xinheng eYu

    2015-02-01

    Full Text Available Photosynthetic microalgae have attracted significant attention as they can serve as important sources for cosmetic, food and pharmaceutical products, industrial materials and even biofuel biodiesels. However, current productivity of microalga-based processes is still very low, which has restricted their scale-up application. In addition to various efforts in strain improvement and cultivation optimization, it was proposed that the productivity of microalga-based processes can also be increased using various chemicals to trigger or enhance cell growth and accumulation of bioproducts. Herein, we summarized recent progresses in applying chemical triggers or enhancers to improve cell growth and accumulation of bioproducts in algal cultures. Based on their enhancing mechanisms, these chemicals can be classified into four categories:chemicals regulating biosynthetic pathways, chemicals inducing oxidative stress responses, phytohormones and analogues regulating multiple aspects of microalgal metabolism, and chemicals directly as metabolic precursors. Taken together, the early researches demonstrated that the use of chemical stimulants could be a very effective and economical way to improve cell growth and accumulation of high-value bioproducts in large-scale cultivation of microalgae.

  6. Microalgal bioengineering for sustainable energy development: Recent transgenesis and metabolic engineering strategies.

    Science.gov (United States)

    Banerjee, Chiranjib; Singh, Puneet Kumar; Shukla, Pratyoosh

    2016-03-01

    Exploring the efficiency of algae to produce remarkable products can be directly benefitted by studying its mechanism at systems level. Recent advents in biotechnology like flux balance analysis (FBA), genomics and in silico proteomics minimize the wet lab exertion. It is understood that FBA predicts the metabolic products, metabolic pathways and alternative pathway to maximize the desired product, and these are key components for microalgae bio-engineering. This review encompasses recent transgenesis techniques and metabolic engineering strategies applied to different microalgae for improving different traits. Further it also throws light on RNAi and riboswitch engineering based methods which may be advantageous for high throughput microalgal research. A valid and optimally designed microalga can be developed where every engineering strategies meet each other successfully and will definitely fulfill the market needs. It is also to be noted that Omics (viz. genetic and metabolic manipulation with bioinformatics) should be integrated to develop a strain which could prove to be a futuristic solution for sustainable development for energy. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. dEMBF: A Comprehensive Database of Enzymes of Microalgal Biofuel Feedstock.

    Science.gov (United States)

    Misra, Namrata; Panda, Prasanna Kumar; Parida, Bikram Kumar; Mishra, Barada Kanta

    2016-01-01

    Microalgae have attracted wide attention as one of the most versatile renewable feedstocks for production of biofuel. To develop genetically engineered high lipid yielding algal strains, a thorough understanding of the lipid biosynthetic pathway and the underpinning enzymes is essential. In this work, we have systematically mined the genomes of fifteen diverse algal species belonging to Chlorophyta, Heterokontophyta, Rhodophyta, and Haptophyta, to identify and annotate the putative enzymes of lipid metabolic pathway. Consequently, we have also developed a database, dEMBF (Database of Enzymes of Microalgal Biofuel Feedstock), which catalogues the complete list of identified enzymes along with their computed annotation details including length, hydrophobicity, amino acid composition, subcellular location, gene ontology, KEGG pathway, orthologous group, Pfam domain, intron-exon organization, transmembrane topology, and secondary/tertiary structural data. Furthermore, to facilitate functional and evolutionary study of these enzymes, a collection of built-in applications for BLAST search, motif identification, sequence and phylogenetic analysis have been seamlessly integrated into the database. dEMBF is the first database that brings together all enzymes responsible for lipid synthesis from available algal genomes, and provides an integrative platform for enzyme inquiry and analysis. This database will be extremely useful for algal biofuel research. It can be accessed at http://bbprof.immt.res.in/embf.

  8. Characterization of a microalgal mutant for CO_2 biofixation and biofuel production

    International Nuclear Information System (INIS)

    Qi, Feng; Pei, Haiyan; Hu, Wenrong; Mu, Ruimin; Zhang, Shuo

    2016-01-01

    Highlights: • Combination of the isolation using 96-well microplates and traditional UV mutagenesis for screening HCT mutant. • Microalgal mutant Chlorella vulgaris SDEC-3M was screened out by modified UV mutagenesis. • SDEC-3M showed high CO_2 tolerance, high CO_2 requiring and relevant genetic stability. • LCE and carbohydrate content of SDEC-3M were significantly elevated. • SDEC-3M offers a strong candidature as CO_2 biofixation and biofuel production. - Abstract: In the present work, a Chlorella vulgaris mutant, named as SDEC-3M, was screened out through the combination of the isolation using 96-well microplates and traditional UV mutagenesis. Compared with its parent (wild type), the growth of SDEC-3M preferred higher CO_2 (15% v/v) environment to ambient air (0.038% CO_2 (v/v)), indicating that the mutant qualified with good tolerance and growth potential under high level CO_2 (high CO_2 tolerance) but was defective in directly utilizing the low level CO_2 (high CO_2 requiring). The genetic stability under ambient air and high level CO_2 was confirmed by a continuous cultivation for five generations. Higher light conversion efficiency (14.52%) and richer total carbohydrate content (42.48%) demonstrated that both solar energy and CO_2 were more effectively productively fixed into carbohydrates for bioethanol production than the parent strain. The mutant would benefit CO_2 biofixation from industrial exhaust gas to mitigate of global warming and promote biofuel production to relieve energy shortage.

  9. Community Structure of Denitrifiers, Bacteria, and Archaea along Redox Gradients in Pacific Northwest Marine Sediments by Terminal Restriction Fragment Length Polymorphism Analysis of Amplified Nitrite Reductase (nirS) and 16S rRNA Genes

    Science.gov (United States)

    Braker, Gesche; Ayala-del-Río, Héctor L.; Devol, Allan H.; Fesefeldt, Andreas; Tiedje, James M.

    2001-01-01

    Steep vertical gradients of oxidants (O2 and NO3−) in Puget Sound and Washington continental margin sediments indicate that aerobic respiration and denitrification occur within the top few millimeters to centimeters. To systematically explore the underlying communities of denitrifiers, Bacteria, and Archaea along redox gradients at distant geographic locations, nitrite reductase (nirS) genes and bacterial and archaeal 16S rRNA genes (rDNAs) were PCR amplified and analyzed by terminal restriction fragment length polymorphism (T-RFLP) analysis. The suitablility of T-RFLP analysis for investigating communities of nirS-containing denitrifiers was established by the correspondence of dominant terminal restriction fragments (T-RFs) of nirS to computer-simulated T-RFs of nirS clones. These clones belonged to clusters II, III, and IV from the same cores and were analyzed in a previous study (G. Braker, J. Zhou, L. Wu, A. H. Devol, and J. M. Tiedje, Appl. Environ. Microbiol. 66:2096–2104, 2000). T-RFLP analysis of nirS and bacterial rDNA revealed a high level of functional and phylogenetic diversity, whereas the level of diversity of Archaea was lower. A comparison of T-RFLPs based on the presence or absence of T-RFs and correspondence analysis based on the frequencies and heights of T-RFs allowed us to group sediment samples according to the sampling location and thus clearly distinguish Puget Sound and the Washington margin populations. However, changes in community structure within sediment core sections during the transition from aerobic to anaerobic conditions were minor. Thus, within the top layers of marine sediments, redox gradients seem to result from the differential metabolic activities of populations of similar communities, probably through mixing by marine invertebrates rather than from the development of distinct communities. PMID:11282647

  10. Marine botany. Second edition

    International Nuclear Information System (INIS)

    Dawes, C.J.

    1998-01-01

    Marine plants are a diverse group that include unicellular algae, seaweeds, seagrasses, salt marshes, and mangrove forests. They carry out a variety of ecological functions and serve as the primary producers in coastal wetlands and oceanic waters. The theme that connects such a wide variety of plants is their ecology, which was also emphasized in the 1981 edition. The goal of this revision is to present taxonomic, physiological, chemical, and ecological aspects of marine plants, their adaptations, and how abiotic and biotic factors interact in their communities. The data are presented in a concise, comparative manner in order to identify similarities and differences between communities such as salt marsh and mangroves or subtidal seaweeds and seagrasses. To accomplish this, the text is organized into five chapters that introduce the marine habitats, consider abiotic and biotic factors, and anthropogenic influences on the communities followed by seven chapters that deal with microalgae, seaweeds, salt marshes, mangroves, seagrasses, and coral reefs. Two appendixes are included; one presents simple field techniques and the other is a summary of seaweed uses

  11. Marine Science

    African Journals Online (AJOL)

    between humans and the coastal and marine environment. ... The journal has a new and more modern layout, published online only, and the editorial .... the population structure of Platorchestia fayetta sp. nov. and their interaction with the.

  12. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the ... tidal height and amplitude can influence light penetra- ...... to environmental parameters in cage culture area of Sepanggar Bay, Malaysia.

  13. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ... consist of special issues on major events or important thematic issues. ... of sources, including plant and animal by- products.

  14. Marine biotoxins

    National Research Council Canada - National Science Library

    2004-01-01

    ... (ciguatera fish poisoning). It discusses in detail the causative toxins produced by marine organisms, chemical structures and analytical methods, habitat and occurrence of the toxin-producing organisms, case studies and existing regulations...

  15. Marine Science

    African Journals Online (AJOL)

    pod diversity and distribution are important especially since studies on marine biodiversity are scarce .... Method II –. Zamoum &. Furla (2012) protocol. Method III. – Geist et al (2008) protocol ..... Public Library Of Science One 8: 51273.

  16. Marine pollution

    International Nuclear Information System (INIS)

    Clark, R.B.

    1992-01-01

    The effects of petroleum, waste materials, halogenated hydrocarbons, radioactivity and heat on the marine ecosystem, the fishing industry and human health are discussed using the example of the North Sea. (orig.) [de

  17. Marine Science

    African Journals Online (AJOL)

    No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form ... to optimize nucleic acid extraction protocols from marine gastropods, present an ...... Greenfield., Gomez E, Harvell CD, Sale PF, Edwards.

  18. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high ..... circulation patterns include the nutrient-rich Somali ...... matical Structures in Computer Science 24: e240311.

  19. Marine insects

    National Research Council Canada - National Science Library

    Cheng, Lanna

    1976-01-01

    .... Not only are true insects, such as the Collembola and insect parasites of marine birds and mammals, considered, but also other kinds of intertidal air-breathing arthropods, notably spiders, scorpions...

  20. Marine Science

    African Journals Online (AJOL)

    Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue .... shell growth is adversely affected. ... local stressors in action, such as ocean acidification ..... that the distribution of many intertidal sessile animals.

  1. Marine harmful algal blooms, human health and wellbeing: challenges and opportunities in the 21st century

    Science.gov (United States)

    BERDALET, ELISA; FLEMING, LORA E.; GOWEN, RICHARD; DAVIDSON, KEITH; HESS, PHILIPP; BACKER, LORRAINE C.; MOORE, STEPHANIE K.; HOAGLAND, PORTER; ENEVOLDSEN, HENRIK

    2015-01-01

    Microalgal blooms are a natural part of the seasonal cycle of photosynthetic organisms in marine ecosystems. They are key components of the structure and dynamics of the oceans and thus sustain the benefits that humans obtain from these aquatic environments. However, some microalgal blooms can cause harm to humans and other organisms. These harmful algal blooms (HABs) have direct impacts on human health and negative influences on human wellbeing, mainly through their consequences to coastal ecosystem services (fisheries, tourism and recreation) and other marine organisms and environments. HABs are natural phenomena, but these events can be favoured by anthropogenic pressures in coastal areas. Global warming and associated changes in the oceans could affect HAB occurrences and toxicity as well, although forecasting the possible trends is still speculative and requires intensive multidisciplinary research. At the beginning of the 21st century, with expanding human populations, particularly in coastal and developing countries, mitigating HABs impacts on human health and wellbeing is becoming a more pressing public health need. The available tools to address this global challenge include maintaining intensive, multidisciplinary and collaborative scientific research, and strengthening the coordination with stakeholders, policymakers and the general public. Here we provide an overview of different aspects of the HABs phenomena, an important element of the intrinsic links between oceans and human health and wellbeing. PMID:26692586

  2. Microalgal technology for remediation of CO{sub 2} from power plant flue gas: A technoeconomic perspective

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, K.L.; Sheehan, J.J. [National Renewable Energy Lab., Golden, CO (United States). Biotechnology Center for Fuels and Chemicals

    1996-12-01

    Power plants burning fossil fuels are a major source of CO{sub 2}, which is implicated in global warming. Microalgal systems, which photosynthetically assimilate CO{sub 2}, can be used to mitigate this major greenhouse gas. A technoeconomic model was developed for trapping CO{sub 2} from flue gases by microalgae in outdoor ponds. The model allows the authors to make some notable observations about the microalgal process. For example, although it was known that the delivered CO{sub 2} cost is an important parameter, this model demonstrates in quantitative terms that the targeted improvements for productivity and lipid content double the relative impact of CO{sub 2} resource cost on total annualized cost of the technology. The model also shows that both algal lipid content and growth rate are important for an economical process, but a trade-off exists between the two, i.e., a high lipid content and low growth rate combination can be as effective as a low lipid content and high growth rate combination. Model predictions were also used to compare the microalgal technology with alternative technologies in terms of CO{sub 2} mitigation costs. The mid-term process, which can be implemented in the near future, is competitive with other CO{sub 2} remediation technologies currently being proposed. Incorporating anticipated advances into the design basis, a CO{sub 2} mitigation cost of $30/t (CO{sub 2} avoided basis) is obtained for the long-term process, which is very promising. Deployment of this technology for CO{sub 2} mitigation looks attractive if research goals put forth by the model are achieved.

  3. Re-envisioning the renewable fuel standard to minimize unintended consequences: A comparison of microalgal diesel with other biodiesels

    International Nuclear Information System (INIS)

    Soratana, Kullapa; Khanna, Vikas; Landis, Amy E.

    2013-01-01

    Highlights: • Conducted a life cycle assessment (LCA) of microalgal diesel from PBR to combustion. • Compared the results with other existing LCA results of petroleum and other biodiesels. • Assessed the current Renewable Fuel Standard (RFS2). • Proposed an approach to set emission thresholds for eutrophication (EP) and smog formation potentials (PSP). • Future RFS should include a life-cycle emissions threshold for EP and PSP. - Abstract: The Renewable Fuel Standard 2 (RFS2) program under the Energy Independence and Security Act of 2007 set a life-cycle emission reduction threshold to only greenhouse gas (GHG) emissions; this type of single-dimensional threshold could lead to the unintended trading of one environmental problem for another. Many of the environmental impacts resulting over the life cycle of oil-crop biodiesel fuels manifest in the agricultural phase of production in the form of water quality degradation. This study investigated the extent to which different biofuels meet the RFS GHG requirement, and presents alternative strategies for minimizing unintended consequences. In addition to life-cycle global warming potential (GWP), the eutrophication potential (EP) and photochemical smog formation potential (PSP) from microalgal diesel were compared to the impacts resulting from petroleum-based diesel, soybean diesel and canola diesel. The results showed tradeoffs between GWP and eutrophication potential when microalgal diesel was compared to soybean diesel. Future RFS criteria should include EP and PSP metrics, however establishing thresholds like the GHG management approach may not be appropriate for these other impacts. Two possible strategies to setting life-cycle eutrophication standards are to establish a threshold based on first generation biofuels, as opposed to petro-fuels or to set maximum levels of EP loads for major watersheds or coastal areas. To decrease PSP, together with existing standards for tailpipe emissions, future RFSs

  4. Databases of the marine metagenomics

    KAUST Repository

    Mineta, Katsuhiko

    2015-10-28

    The metagenomic data obtained from marine environments is significantly useful for understanding marine microbial communities. In comparison with the conventional amplicon-based approach of metagenomics, the recent shotgun sequencing-based approach has become a powerful tool that provides an efficient way of grasping a diversity of the entire microbial community at a sampling point in the sea. However, this approach accelerates accumulation of the metagenome data as well as increase of data complexity. Moreover, when metagenomic approach is used for monitoring a time change of marine environments at multiple locations of the seawater, accumulation of metagenomics data will become tremendous with an enormous speed. Because this kind of situation has started becoming of reality at many marine research institutions and stations all over the world, it looks obvious that the data management and analysis will be confronted by the so-called Big Data issues such as how the database can be constructed in an efficient way and how useful knowledge should be extracted from a vast amount of the data. In this review, we summarize the outline of all the major databases of marine metagenome that are currently publically available, noting that database exclusively on marine metagenome is none but the number of metagenome databases including marine metagenome data are six, unexpectedly still small. We also extend our explanation to the databases, as reference database we call, that will be useful for constructing a marine metagenome database as well as complementing important information with the database. Then, we would point out a number of challenges to be conquered in constructing the marine metagenome database.

  5. Time series monitoring of water quality and microalgal diversity in a tropical bay under intense anthropogenic interference (SW coast of the Bay of Bengal, India)

    Energy Technology Data Exchange (ETDEWEB)

    Shaik, Aziz ur Rahman [CSIR — National Institute of Oceanography, Regional Centre, 176 Lawson' s Bay Colony, Visakhapatnam, AP 530017 (India); Biswas, Haimanti, E-mail: haimanti.biswas@nio.org [CSIR — National Institute of Oceanography, Regional Centre, 176 Lawson' s Bay Colony, Visakhapatnam, AP 530017 (India); Reddy, N.P.C.; Srinivasa Rao, V. [CSIR — National Institute of Oceanography, Regional Centre, 176 Lawson' s Bay Colony, Visakhapatnam, AP 530017 (India); Bharathi, M.D. [Present address: ICMAM Project Directorate, 2nd Floor, NIOT Campus, Velacherry-Tambaram Main Road, Pallikkaranai, Chennai 600100 (India); Subbaiah, Ch.V. [CSIR — National Institute of Oceanography, Regional Centre, 176 Lawson' s Bay Colony, Visakhapatnam, AP 530017 (India)

    2015-11-15

    In recent decades, material fluxes to coastal waters from various land based anthropogenic activities have significantly been enhanced around the globe which can considerably impact the coastal water quality and ecosystem health. Hence, there is a critical need to understand the links between anthropogenic activities in watersheds and its health. Kakinada Bay is situated at the SW part of the Bay of Bengal, near to the second largest mangrove cover in India with several fertilizer industries along its bank and could be highly vulnerable to different types of pollutants. However, virtually, no data is available so far reporting its physicochemical status and microalgal diversity at this bay. In order to fill this gap, we conducted three time series observations at a fixed station during January, December and June 2012, at this bay measuring more than 15 physical, chemical and biological parameters in every 3 h over a period of 36 h in both surface (0 m) and subsurface (4.5 m) waters. Our results clearly depict a strong seasonality between three sampling months; however, any abnormal values of nutrients, biological oxygen demand or dissolved oxygen level was not observed. A Skeletonema costatum bloom was observed in December which was probably influenced by low saline, high turbid and high Si input through the river discharge. Otherwise, smaller diatoms like Thalassiosira decipiens, Thalassiothrix frauenfeldii, and Thalassionema nitzschioides dominated the bay. It is likely that the material loading can be high at the point sources due to intense anthropogenic activities, however, gets diluted with biological, chemical and physical processes in the offshore waters. - Highlights: • No signature of enormous nutrient loading was observed over the diel cycle • Dissolved oxygen and BOD concentrations did not show any exceptional trend • Diatoms dominated more than 90% of the total phytoplankton communities • A Skeletonema Costatum (a centric diatom) bloom was

  6. Time series monitoring of water quality and microalgal diversity in a tropical bay under intense anthropogenic interference (SW coast of the Bay of Bengal, India)

    International Nuclear Information System (INIS)

    Shaik, Aziz ur Rahman; Biswas, Haimanti; Reddy, N.P.C.; Srinivasa Rao, V.; Bharathi, M.D.; Subbaiah, Ch.V.

    2015-01-01

    In recent decades, material fluxes to coastal waters from various land based anthropogenic activities have significantly been enhanced around the globe which can considerably impact the coastal water quality and ecosystem health. Hence, there is a critical need to understand the links between anthropogenic activities in watersheds and its health. Kakinada Bay is situated at the SW part of the Bay of Bengal, near to the second largest mangrove cover in India with several fertilizer industries along its bank and could be highly vulnerable to different types of pollutants. However, virtually, no data is available so far reporting its physicochemical status and microalgal diversity at this bay. In order to fill this gap, we conducted three time series observations at a fixed station during January, December and June 2012, at this bay measuring more than 15 physical, chemical and biological parameters in every 3 h over a period of 36 h in both surface (0 m) and subsurface (4.5 m) waters. Our results clearly depict a strong seasonality between three sampling months; however, any abnormal values of nutrients, biological oxygen demand or dissolved oxygen level was not observed. A Skeletonema costatum bloom was observed in December which was probably influenced by low saline, high turbid and high Si input through the river discharge. Otherwise, smaller diatoms like Thalassiosira decipiens, Thalassiothrix frauenfeldii, and Thalassionema nitzschioides dominated the bay. It is likely that the material loading can be high at the point sources due to intense anthropogenic activities, however, gets diluted with biological, chemical and physical processes in the offshore waters. - Highlights: • No signature of enormous nutrient loading was observed over the diel cycle • Dissolved oxygen and BOD concentrations did not show any exceptional trend • Diatoms dominated more than 90% of the total phytoplankton communities • A Skeletonema Costatum (a centric diatom) bloom was

  7. Broad-Scale Comparison of Photosynthesis in Terrestrial and Aquatic Plant Communities

    DEFF Research Database (Denmark)

    Sand-Jensen, Kaj; Krause-Jensen, D.

    1997-01-01

    Comparisons of photosynthesis in terrestrial and aquatic habitats have been impaired by differences in methods and time-scales of measurements. We compiled information on gross photosynthesis at high irradiance and photosynthetic efficiency at low irradiance from 109 published terrestrial studies...... communities probably due to more efficient light utilization and gas exchange in the terrestrial habitats. By contrast only small differences were found within different aquatic plant communities or within different terrestrial plant communities....... of forests, grasslands and crops and 319 aquatic studies of phytoplankton, macrophyte and attached microalgal communities to test if specific differences existed between the communities. Maximum gross photosynthesis and photosynthetic efficiency were systematically higher in terrestrial than in aquatic...

  8. Exogenous Gene Integration for Microalgal Cell Transformation Using a Nanowire-Incorporated Microdevice.

    Science.gov (United States)

    Bae, Sunwoong; Park, Seunghye; Kim, Jung; Choi, Jong Seob; Kim, Kyung Hoon; Kwon, Donguk; Jin, EonSeon; Park, Inkyu; Kim, Do Hyun; Seo, Tae Seok

    2015-12-16

    Superior green algal cells showing high lipid production and rapid growth rate are considered as an alternative for the next generation green energy resources. To achieve the biomass based energy generation, transformed microalgae with superlative properties should be developed through genetic engineering. Contrary to the normal cells, microalgae have rigid cell walls, so that target gene delivery into cells is challengeable. In this study, we report a ZnO nanowire-incorporated microdevice for a high throughput microalgal transformation. The proposed microdevice was equipped with not only a ZnO nanowire in the microchannel for gene delivery into cells but also a pneumatic polydimethylsiloxane (PDMS) microvalve to modulate the cellular attachment and detachment from the nanowire. As a model, hygromycin B resistance gene cassette (Hyg3) was functionalized on the hydrothermally grown ZnO nanowires through a disulfide bond and released into green algal cells, Chlamydomonas reinhardtii, by reductive cleavage. During Hyg3 gene delivery, a monolithic PDMS membrane was bent down, so that algal cells were pushed down toward ZnO nanowires. The supply of vacuum in the pneumatic line made the PDMS membrane bend up, enabling the gene delivered algal cells to be recovered from the outlet of the microchannel. We successfully confirmed Hyg3 gene integrated in microalgae by amplifying the inserted gene through polymerase chain reaction (PCR) and DNA sequencing. The efficiency of the gene delivery to algal cells using the ZnO nanowire-incorporated microdevice was 6.52 × 10(4)- and 9.66 × 10(4)-fold higher than that of a traditional glass bead beating and electroporation.

  9. Modelling growth of, and removal of Zn and Hg by a wild microalgal consortium

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Cristina M.; Brandao, Teresa R.S.; Castro, Paula M.L. [Universidade Catolica Portuguesa, Porto (Portugal). CBQF/Escola Superior de Biotecnologia; Malcata, F. Xavier [ISMAI - Instituto Superior da Maia, Avioso S. Pedro (Portugal); CIMAR/CIIMAR - Centro Interdisciplinar de Investigacao Marinha e Ambiental, Porto (Portugal)

    2012-04-15

    Microorganisms isolated from sites contaminated with heavy metals usually possess a higher removal capacity than strains from regular cultures. Heavy metal-containing soil samples from an industrial dumpsite in Northern Portugal were accordingly collected; following enrichment under metal stress, a consortium of wild microalgae was obtained. Their ability to grow in the presence of, and their capacity to recover heavy metals was comprehensively studied; the datasets thus generated were fitted to by a combined model of biomass growth and metal uptake, derived from first principles. After exposure to 15 and 25 mg/L Zn{sup 2+} for 6 days, the microalgal consortium reached similar, or higher cell density than the control; however, under 50 and 65 mg/L Zn{sup 2+}, 71% to 84% inhibition was observed. Growth in the presence of Hg{sup 2+} was significantly inhibited, even at a concentration as low as 25 {mu}g/L, and 90% inhibition was observed above 100 {mu}g/L. The maximum amount of Zn{sup 2+} removed was 21.3 mg/L, upon exposure to 25 mg/L for 6 day, whereas the maximum removal of Hg{sup 2+} was 335 {mu}g/L, upon 6 day in the presence of 350 {mu}g/L. The aforementioned mechanistic model was built upon Monod assumptions (including heavy metal inhibition), coupled with Leudeking-Piret relationships between the rates of biomass growth and metal removal. The overall fits were good under all experimental conditions tested, thus conveying a useful tool for rational optimisation of microalga-mediated bioremediation. (orig.)

  10. Microalgal Metabolic Network Model Refinement through High-Throughput Functional Metabolic Profiling

    International Nuclear Information System (INIS)

    Chaiboonchoe, Amphun; Dohai, Bushra Saeed; Cai, Hong; Nelson, David R.; Jijakli, Kenan; Salehi-Ashtiani, Kourosh

    2014-01-01

    Metabolic modeling provides the means to define metabolic processes at a systems level; however, genome-scale metabolic models often remain incomplete in their description of metabolic networks and may include reactions that are experimentally unverified. This shortcoming is exacerbated in reconstructed models of newly isolated algal species, as there may be little to no biochemical evidence available for the metabolism of such isolates. The phenotype microarray (PM) technology (Biolog, Hayward, CA, USA) provides an efficient, high-throughput method to functionally define cellular metabolic activities in response to a large array of entry metabolites. The platform can experimentally verify many of the unverified reactions in a network model as well as identify missing or new reactions in the reconstructed metabolic model. The PM technology has been used for metabolic phenotyping of non-photosynthetic bacteria and fungi, but it has not been reported for the phenotyping of microalgae. Here, we introduce the use of PM assays in a systematic way to the study of microalgae, applying it specifically to the green microalgal model species Chlamydomonas reinhardtii. The results obtained in this study validate a number of existing annotated metabolic reactions and identify a number of novel and unexpected metabolites. The obtained information was used to expand and refine the existing COBRA-based C. reinhardtii metabolic network model iRC1080. Over 254 reactions were added to the network, and the effects of these additions on flux distribution within the network are described. The novel reactions include the support of metabolism by a number of d-amino acids, l-dipeptides, and l-tripeptides as nitrogen sources, as well as support of cellular respiration by cysteamine-S-phosphate as a phosphorus source. The protocol developed here can be used as a foundation to functionally profile other microalgae such as known microalgae mutants and novel isolates.

  11. Microalgal Metabolic Network Model Refinement through High-Throughput Functional Metabolic Profiling

    Energy Technology Data Exchange (ETDEWEB)

    Chaiboonchoe, Amphun; Dohai, Bushra Saeed; Cai, Hong; Nelson, David R. [Division of Science and Math, New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi Institute, Abu Dhabi (United Arab Emirates); Jijakli, Kenan [Division of Science and Math, New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi Institute, Abu Dhabi (United Arab Emirates); Engineering Division, Biofinery, Manhattan, KS (United States); Salehi-Ashtiani, Kourosh, E-mail: ksa3@nyu.edu [Division of Science and Math, New York University Abu Dhabi, Abu Dhabi (United Arab Emirates); Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi Institute, Abu Dhabi (United Arab Emirates)

    2014-12-10

    Metabolic modeling provides the means to define metabolic processes at a systems level; however, genome-scale metabolic models often remain incomplete in their description of metabolic networks and may include reactions that are experimentally unverified. This shortcoming is exacerbated in reconstructed models of newly isolated algal species, as there may be little to no biochemical evidence available for the metabolism of such isolates. The phenotype microarray (PM) technology (Biolog, Hayward, CA, USA) provides an efficient, high-throughput method to functionally define cellular metabolic activities in response to a large array of entry metabolites. The platform can experimentally verify many of the unverified reactions in a network model as well as identify missing or new reactions in the reconstructed metabolic model. The PM technology has been used for metabolic phenotyping of non-photosynthetic bacteria and fungi, but it has not been reported for the phenotyping of microalgae. Here, we introduce the use of PM assays in a systematic way to the study of microalgae, applying it specifically to the green microalgal model species Chlamydomonas reinhardtii. The results obtained in this study validate a number of existing annotated metabolic reactions and identify a number of novel and unexpected metabolites. The obtained information was used to expand and refine the existing COBRA-based C. reinhardtii metabolic network model iRC1080. Over 254 reactions were added to the network, and the effects of these additions on flux distribution within the network are described. The novel reactions include the support of metabolism by a number of d-amino acids, l-dipeptides, and l-tripeptides as nitrogen sources, as well as support of cellular respiration by cysteamine-S-phosphate as a phosphorus source. The protocol developed here can be used as a foundation to functionally profile other microalgae such as known microalgae mutants and novel isolates.

  12. Dual uses of microalgal biomass: An integrative approach for biohydrogen and biodiesel production

    International Nuclear Information System (INIS)

    Dasgupta, Chitralekha Nag; Suseela, M.R.; Mandotra, S.K.; Kumar, Pankaj; Pandey, Manish K.; Toppo, Kiran; Lone, J.A.

    2015-01-01

    Highlights: • Chlorella sp. NBRI029 and Scenedesmus sp. NBRI012 shows high biomass productivity. • Scenedesmus sp. NBRI012 shows maximum H 2 evolution in 6th day of fermentation. • Residual biomass after H 2 production contains high lipid content. • Lipid extracted from the residual biomass fulfills various biodiesel properties. - Abstract: Dual application of biomass for biohydrogen and biodiesel production could be considered a feasible option for economic and sustainable energy production from microalgae. In this study, after a large screening of fresh water microalgal isolates, Scenedesmus sp. NBRI012 and Chlorella sp. NBRI029 have exhibited high biomass (1.31 ± 0.11 and 2.62 ± 0.13 g/L respectively) and lipid (244.44 ± 12.3 and 587.38 ± 20.2 mg/L respectively) yield with an organic carbon (acetate) source. Scenedesmus sp. NBRI012 has shown the highest H 2 (maximum evolution of 17.72% v/v H 2 of total gases) production; it produced H 2 continuously for seven days in sulfur-deprived TAP media. Sulfur deprivation during the H 2 production was found to increase the lipid content (410.03 ± 18.5 mg/L) of the residual biomass. Fatty acid profile of the lipid extracted from the residual biomass of Scenedesmus sp. NBRI012 has showed abundance of fatty acids with a carbon chain length of C16 and C18. Cetane number, iodine value, and saponification value of biodiesel were found suitable according to the range given by the Indian standard (IS 15607), Brazilian National Petroleum Agency (ANP255) and the European biodiesel standard EN14214

  13. Feasibility study of microalgal and jatropha biodiesel production plants: Exergy analysis approach

    International Nuclear Information System (INIS)

    Ofori-Boateng, Cynthia; Keat, Teong Lee; JitKang, Lim

    2012-01-01

    The exergy analyses performed in this study are based on three thermodynamic performance parameters namely exergy destruction, exergy efficiency and thermodynamic improvement potentials. After mathematical analysis with Aspen Plus software, the results showed that 64% and 44% of the total exergy content of the input resources into microalgal methyl ester (MME) and jatropha methyl ester (JME) production plants were destroyed respectively for 1 ton of biodiesel produced. This implies that only 36% and 56% (for MME and JME production plants respectively) useful energy in the products is available to do work. The highest and lowest exergy destructions were recorded in the oil extraction units (38% and 39% of the total exergy destroyed for MME and JME plants respectively) and transesterification units (5% and 2% of total exergy destroyed for MME and JME plants respectively) respectively for 1 ton biodiesel produced. Since sustainable biodiesel production depends on cultivation of feedstock, oil extraction and transesterification processes, exergy analysis which is carried out on only the transesterification unit cannot justify the thermodynamic feasibility of the whole biodiesel production plant unless a complete thermodynamic assessment has been done for the whole plant. Thus, according to this study which considers all the biodiesel production processes, MME and JME production plants are not thermodynamically feasible. - Highlights: ► 64% of exergy content of input resources into MME production plant is destroyed. ► 44% of exergy content of input resources into JME production plant is destroyed. ► Exergetic efficiencies of MME and JME production plants are far less than 1. ► Thermodynamically, MME and JME production plants are unsustainable. ► Exergy loss can be reduced by using heat integrated reactive distillation process.

  14. Otters, Marine

    Science.gov (United States)

    Estes, James A.; Bodkin, James L.; Ben-David, M.; Perrin, William F.; Würsing, Bernd; Thewissen, J.G.M.

    2009-01-01

    The otters (Mustelidae; Lutrinae) provide an exceptional perspective into the evolution of marine living by mammals. Most extant marine mammals (e.g. the cetaceans, pinnipeds, and sirenians) have been so highly modified by long periods of selection for life in the sea that they bear little resemblance to their terrestrial ancestors. Marine otters, in contrast, are more recent expatriates from freshwater habitats and some species still live in both environments. Contrasts among species within the otters, and among the otters, terrestrial mammals, and the more highly adapted pinnipeds and cetaceans provide powerful insights into mammalian adaptations to life in the sea (Estes, 1989). Among the marine mammals, sea otters (Enhydra lutris, Fig. 1) provide the clearest understanding of consumer-induced effects on ecosystem function. This is due in part to opportunities provided by history and in part to the relative ease with which shallow coastal systems where sea otters live can be observed and studied. Although more difficult to study than sea otters, other otter species reveal the connectivity among the marine, freshwater, and terrestrial systems. These three qualities of the otters – their comparative biology, their role as predators, and their role as agents of ecosystem connectivity – are what make them interesting to marine mammalogy.The following account provides a broad overview of the comparative biology and ecology of the otters, with particular emphasis on those species or populations that live in the sea. Sea otters are features prominently, in part because they live exclusively in the sea whereas other otters have obligate associations with freshwater and terrestrial environments (Kenyon, 1969; Riedman and Estes, 1990).

  15. Marine Battlefields

    DEFF Research Database (Denmark)

    Harðardóttir, Sara

    as they are an important food source for various marine animals. For both phytoand zooplankton predation is a major cause of mortality, and strategies for protection or avoidance are important for survival. Diatoms of the genera Nitzschia and Pseudo-nitzschia are known to produce a neuro-toxin, domoic acid (DA). Despite......Phytoplankton species are photosynthetic organisms found in most aquatic habitats. In the ocean, phytoplankton are tremendously important because they produce the energy that forms the base of the marine food web. Zooplankton feed on phytoplankton and mediate the energy to higher trophic levels...

  16. Parasite communities: patterns and processes

    National Research Council Canada - National Science Library

    Esch, Gerald W; Bush, Albert O; Aho, John M

    1990-01-01

    .... Taking examples from many hosts including molluscs, marine and freshwater fish, amphibians, reptiles, birds and mammals, this book shows how parasitic communities are influenced by a multitude...

  17. Enzymatic Processes in Marine Biotechnology.

    Science.gov (United States)

    Trincone, Antonio

    2017-03-25

    In previous review articles the attention of the biocatalytically oriented scientific community towards the marine environment as a source of biocatalysts focused on the habitat-related properties of marine enzymes. Updates have already appeared in the literature, including marine examples of oxidoreductases, hydrolases, transferases, isomerases, ligases, and lyases ready for food and pharmaceutical applications. Here a new approach for searching the literature and presenting a more refined analysis is adopted with respect to previous surveys, centering the attention on the enzymatic process rather than on a single novel activity. Fields of applications are easily individuated: (i) the biorefinery value-chain, where the provision of biomass is one of the most important aspects, with aquaculture as the prominent sector; (ii) the food industry, where the interest in the marine domain is similarly developed to deal with the enzymatic procedures adopted in food manipulation; (iii) the selective and easy extraction/modification of structurally complex marine molecules, where enzymatic treatments are a recognized tool to improve efficiency and selectivity; and (iv) marine biomarkers and derived applications (bioremediation) in pollution monitoring are also included in that these studies could be of high significance for the appreciation of marine bioprocesses.

  18. Marine Microalgae with Anti-Cancer Properties.

    Science.gov (United States)

    Martínez Andrade, Kevin A; Lauritano, Chiara; Romano, Giovanna; Ianora, Adrianna

    2018-05-15

    Cancer is the leading cause of death globally and finding new therapeutic agents for cancer treatment remains a major challenge in the pursuit for a cure. This paper presents an overview on microalgae with anti-cancer activities. Microalgae are eukaryotic unicellular plants that contribute up to 40% of global primary productivity. They are excellent sources of pigments, lipids, carotenoids, omega-3 fatty acids, polysaccharides, vitamins and other fine chemicals, and there is an increasing demand for their use as nutraceuticals and food supplements. Some microalgae are also reported as having anti-cancer activity. In this review, we report the microalgal species that have shown anti-cancer properties, the cancer cell lines affected by algae and the concentrations of compounds/extracts tested to induce arrest of cell growth. We also report the mediums used for growing microalgae that showed anti-cancer activity and compare the bioactivity of these microalgae with marine anticancer drugs already on the market and in phase III clinical trials. Finally, we discuss why some microalgae can be promising sources of anti-cancer compounds for future development.

  19. Microalgal technology for remediation of CO{sub 2} from power plant flue gas: A techno-economic perspective

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, K.L. [National Renewable Energy Lab., Golden, CO (United States)

    1996-12-31

    Power plants burning fossil fuels are a major source of CO{sub 2} which is implicated in global warming. Microalgal systems which photosynthetically assimilate carbon dioxide can be used for mitigation of this major greenhouse gas. A techno-economic model was developed for trapping carbon dioxide from flue gases by microalgae in outdoor ponds. The model also shows that algal lipid content and growth rate are both important for an economical process, but a trade-off exists between the two, i.e., a high lipid content and low growth rate combination can be as effective as a low lipid content and high growth rate combination. Hence, these two parameters may be treated as a composite parameter to be optimized to yield the least CO{sub 2} mitigation cost. Model predictions were also used to compare the microalgal technology with alternative technologies in terms of CO{sub 2} mitigation costs. Incorporating advances anticipated in the future into the design basis, the model yields a CO{sub 2} mitigation cost that is competitive with other CO{sub 2} remediation technologies currently being proposed. Furthermore, this technology also provides a lipid feedstock for producing a renewable fuel such as biodiesel. Deployment of this technology for CO{sub 2} mitigation looks attractive if research goals put forth by the model are achieved.

  20. Simultaneous improvement in production of microalgal biodiesel and high-value alpha-linolenic acid by a single regulator acetylcholine.

    Science.gov (United States)

    Parsaeimehr, Ali; Sun, Zhilan; Dou, Xiao; Chen, Yi-Feng

    2015-01-01

    Photoautotrophic microalgae are a promising avenue for sustained biodiesel production, but are compromised by low yields of biomass and lipids at present. We are developing a chemical approach to improve microalgal accumulation of feedstock lipids as well as high-value alpha-linolenic acid which in turn might provide a driving force for biodiesel production. We demonstrate the effectiveness of the small bioactive molecule "acetylcholine" on accumulation of biomass, total lipids, and alpha-linolenic acid in Chlorella sorokiniana. The effectiveness exists in different species of Chlorella. Moreover, the precursor and analogs of acetylcholine display increased effectiveness at higher applied doses, with maximal increases by 126, 80, and 60% over controls for biomass, total lipids, and alpha-linolenic acid, respectively. Production of calculated biodiesel was also improved by the precursor and analogs of acetylcholine. The biodiesel quality affected by changes in microalgal fatty acid composition was addressed. The chemical approach described here could improve the lipid yield and biodiesel production of photoautotrophic microalgae if combined with current genetic approaches.

  1. Lipid Production of Heterotrophic Chlorella sp. from Hydrolysate Mixtures of Lipid-Extracted Microalgal Biomass Residues and Molasses.

    Science.gov (United States)

    Zheng, Hongli; Ma, Xiaochen; Gao, Zhen; Wan, Yiqin; Min, Min; Zhou, Wenguang; Li, Yun; Liu, Yuhuan; Huang, He; Chen, Paul; Ruan, Roger

    2015-10-01

    This study investigated the feasibility of lipid production of Chlorella sp. from waste materials. Lipid-extracted microalgal biomass residues (LMBRs) and molasses were hydrolyzed, and their hydrolysates were analyzed. Five different hydrolysate mixture ratios (w/w) of LMBRs/molasses (1/0, 1/1, 1/4, 1/9, and 0/1) were used to cultivate Chlorella sp. The results showed that carbohydrate and protein were the two main compounds in the LMBRs, and carbohydrate was the main compound in the molasses. The highest biomass concentration of 5.58 g/L, Y biomass/sugars of 0.59 g/g, lipid productivity of 335 mg/L/day, and Y lipids/sugars of 0.25 g/g were obtained at the hydrolysate mixture ratio of LMBRs/molasses of 1/4. High C/N ratio promoted the conversion of sugars into lipids. The lipids extracted from Chlorella sp. shared similar lipid profile of soybean oil and is therefore a potential viable biodiesel feedstock. These results showed that Chlorella sp. can utilize mixed sugars and amino acids from LMBRs and molasses to accumulate lipids efficiently, thus reducing the cost of microalgal biodiesel production and improving its economic viability.

  2. A cost analysis of microalgal biomass and biodiesel production in open raceways treating municipal wastewater and under optimum light wavelength.

    Science.gov (United States)

    Kang, Zion; Kim, Byung-Hyuk; Ramanan, Rishiram; Choi, Jong-Eun; Yang, Ji-Won; Oh, Hee-Mock; Kim, Hee-Sik

    2015-01-01

    Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the effect of using wastewater and wavelength filters on microalgal productivity. Experimental results were then fitted into a model, and cost analysis was performed in comparison with control raceways. Three different microalgal strains, Chlorella vulgaris AG10032, Chlorella sp. JK2, and Scenedesmus sp. JK10, were tested for nutrient removal under different light wavelengths (blue, green, red, and white) using filters in batch cultivation. Blue wavelength showed an average of 27% higher nutrient removal and at least 42% higher chemical oxygen demand removal compared with white light. Naturally, the specific growth rate of microalgae cultivated under blue wavelength was on average 10.8% higher than white wavelength. Similarly, lipid productivity was highest in blue wavelength, at least 46.8% higher than white wavelength, whereas FAME composition revealed a mild increase in oleic and palmitic acid levels. Cost analysis reveals that raceways treating wastewater and using monochromatic wavelength would decrease costs from 2.71 to 0.73 $/kg biomass. We prove that increasing both biomass and lipid productivity is possible through cost-effective approaches, thereby accelerating the commercialization of low-value products from microalgae, like biodiesel.

  3. Molecular characterization of two microalgal strains in Egypt and investigation of the antimicrobial activity of their extracts

    Directory of Open Access Journals (Sweden)

    El Semary, NA.

    2013-01-01

    Full Text Available The emergence of new pathogens and the increasing drug-resistance of recognized ones pose a difficult challenge. One way that this challenge is being addressed is through the discovery of new cost-effective drug resources in the form of bioactive compounds. Algae represent a promising source of bioactive compounds in this regard. In the present research, we used molecular and phylogenetic analysis to isolate and identify two microalgal strains. We found that one strain belonged to the phylum chrysophyta and the other to the cyanobacteria. We also investigated the antimicrobial activity of some of the lipophilic extracts of the two microalgal strains. Several fractions showed high individual antimicrobial bioactivity against multidrug-resistant Salmonella sp., Citrobacter sp., Aspergillus niger and Aspergillus flavus. Fraction III from Poterioochromonas malhamensis showed the highest level of activity against two multidrug-resistant bacterial pathogens. The inhibition zone diameter was 1.4 cm for Salmonella and 1.4 cm for Citrobacter. Meanwhile, another lipophilic fraction from the cyanobacterium Synechocystis salina showed broad-spectrum bioactivity (inhibition zone diameter of 0.9 cm for Aspergillus niger, 1 cm for Citrobacter and 0.9 cm for Salmonella. One lipophilic fraction from Aphanizomenon showed antifungal bioactivity against Aspergillus niger and Aspergillus flavus, where the inhibition zone diameter was 1.1 cm and 1.0 cm, respectively. The study highlights the antimicrobial bioactivity of extracts from local microalgae and emphasizes the importance of carrying out screening programs for those microorganisms.

  4. Extraction of microalgal lipids and the influence of polar lipids on biodiesel production by lipase-catalyzed transesterification.

    Science.gov (United States)

    Navarro López, Elvira; Robles Medina, Alfonso; González Moreno, Pedro Antonio; Esteban Cerdán, Luis; Molina Grima, Emilio

    2016-09-01

    In order to obtain microalgal saponifiable lipids (SLs) fractions containing different polar lipid (glycolipids and phospholipids) contents, SLs were extracted from wet Nannochloropsis gaditana microalgal biomass using seven extraction systems, and the polar lipid contents of some fractions were reduced by low temperature acetone crystallization. We observed that the polar lipid content in the extracted lipids depended on the polarity of the first solvent used in the extraction system. Lipid fractions with polar lipid contents between 75.1% and 15.3% were obtained. Some of these fractions were transformed into fatty acid methyl esters (FAMEs, biodiesel) by methanolysis, catalyzed by the lipases Novozym 435 and Rhizopus oryzae in tert-butanol medium. We observed that the reaction velocity was higher the lower the polar lipid content, and that the final FAME conversions achieved after using the same lipase batch to catalyze consecutive reactions decreased in relation to an increase in the polar lipid content. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Anaerobic Degradation of Marine Algae, Seagrass and Tropical Climbing Vines to Produce a Renewable Energy Source and the Analysis of Their Anaerobic Microbial Communities

    Science.gov (United States)

    2013-01-01

    specific mechanisms and enzymes as a result of their complex structure. For these reasons there have been searches for other biomasses that may...Te’o, V., Saul, D., Morgan, H. 1999. Molecular diversity of thermophilic cellulolytic and hemicellulolytic bacteria. Microbiology Ecology, 28:99-110...lyase genes from deep-sea strains of Vibrio and Agarivorans and characterization of a new Vibrio enzyme . Marine Biotechnology, 12:526-533. Ugwu, C

  6. Harvesting microalgae using activated sludge can decrease polymer dosing and enhance methane production via co-digestion in a bacterial-microalgal process

    DEFF Research Database (Denmark)

    Wágner, Dorottya Sarolta; Radovici, Maria; Smets, Barth F.

    2016-01-01

    , there is the potential to produce energy by co-digesting the two types of biomass. We present an innovative approach to recover microalgal biomass via a two-step flocculation using bacterial biomass after the destabilisation of microalgae with conventional cationic polymer. A short solids retention time (SRT) enhanced...

  7. Marine Science

    African Journals Online (AJOL)

    Science. The journal has a new and more modern layout, published online only, and the editorial. Board was increased to include more disciplines pertaining to marine sciences. While important chal- lenges still lie ahead, we are steadily advancing our standard to increase visibility and dissemination throughout the global ...

  8. Marine Mammals.

    Science.gov (United States)

    Meith, Nikki

    Marine mammals have not only fascinated and inspired human beings for thousands of years, but they also support a big business by providing flesh for sea-borne factories, sustaining Arctic lifestyles and traditions, and attracting tourists to ocean aquaria. While they are being harpooned, bludgeoned, shot, netted, and trained to jump through…

  9. Marine Science

    African Journals Online (AJOL)

    Mauritius Marine Conservation Society through their. Abstract. While no populations of seals are resident in the tropical Indian Ocean, vagrant animals are occasionally sighted in the region. Here we detail two new sightings of pinnipeds in the Mascarene Islands (Mauritius, Reunion and Rodri- gues) since 1996 and review ...

  10. Marine Science

    African Journals Online (AJOL)

    J O U R N A L O F. Marine Science. Coral reefs of Mauritius in a changing global climate ..... in confined aquifers, and a lesser influence in uncon- fined systems. On the ... massive cloud cover during the critical months, some. 70% bleaching ...

  11. Marine Science

    African Journals Online (AJOL)

    Copy Editor Timothy Andrew. Published ... 2007; Zhou et al., 2009) and they play an important role in the ... At both sites, zonal variation in TMPB was evident with significantly higher C-biomass closer to ... ton is considered to be an essential parameter in eco- systems ...... logical significance of toxic marine dinoflagellates.

  12. Marine Science

    African Journals Online (AJOL)

    No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means ... USA/Norway ... The last couple of years have been a time of change for the Western Indian Ocean Journal of Marine.

  13. Marine Science

    African Journals Online (AJOL)

    Chief Editor José Paula | Faculty of Sciences of University of Lisbon, Portugal. Copy Editor Timothy Andrew. Published biannually. Aims and scope: The Western Indian Ocean Journal of Marine Science provides an avenue for the wide dissem- ination of high quality research generated in the Western Indian Ocean (WIO) ...

  14. Fatty acid composition and bacterial community changes in the rumen fluid of lactating sheep fed sunflower oil plus incremental levels of marine algae.

    Science.gov (United States)

    Toral, P G; Belenguer, A; Shingfield, K J; Hervás, G; Toivonen, V; Frutos, P

    2012-02-01

    Supplementation of ruminant diets with plant oils and marine lipids is an effective strategy for lowering saturated fatty acid (FA) content and increasing the concentration of cis-9,trans-11 conjugated linoleic acid and long-chain n-3 FA in ruminant milk. However, changes in populations of ruminal microorganisms associated with altered biohydrogenation of dietary unsaturated FA are not well characterized. Twenty-five lactating Assaf ewes were allocated at random to 1 of 5 treatments composed of dehydrated alfalfa hay and concentrates containing no additional lipid (control), or supplemented with 25 g of sunflower oil and 0 (SO), 8 (SOMA(1)), 16 (SOMA(2)), or 24 (SOMA(3)) g of marine algae/kg of diet dry matter. On d 28 on diet, samples of rumen fluid were collected for lipid analysis and microbial DNA extraction. Appearance and identification of biohydrogenation intermediates was determined based on complementary gas chromatography and Ag+-HPLC analysis of FA methyl esters. Total bacteria and the Butyrivibrio group were studied in microbial DNA by terminal RFLP analysis, and real-time PCR was used to quantify the known Butyrivibrio bacteria that produce trans-11 18:1 or 18:0. Dietary supplements of sunflower oil alone or in combination with marine algae altered the FA profile of rumen fluid, which was associated with changes in populations of specific bacteria. Inclusion of marine algae in diets containing sunflower oil resulted in the accumulation of trans 18:1 and 10-O-18:0 and a marked decrease in 18:0 concentrations in rumen fluid. At the highest levels of supplementation (SOMA(2) and SOMA(3)), marine algae also promoted a shift in ruminal biohydrogenation pathways toward the formation of trans-10 18:1 at the expense of trans-11 18:1. Changes in the concentration of biohydrogenation intermediates were not accompanied by significant variations in the abundance of known cultivated ruminal bacteria capable of hydrogenating unsaturated FA. However, certain

  15. Lipid extracted microalgal biomass residue as a fertilizer substitute for Zea mays L

    Directory of Open Access Journals (Sweden)

    Rahulkumar eMaurya

    2016-01-01

    Full Text Available High volumes of lipid extracted microalgal biomass residues (LMBRs are expected to be produced upon commencement of biodiesel production on a large scale, thus necessitating its value addition for sustainable development. LMBRs of Chlorella variabilis and Lyngbya majuscula were employed to substitute the nitrogen content of recommended rate of fertilizer (RRF for Zea mays L. The pot experiment comprised of 10 treatments, i.e. T1 (No fertilizer; T2 (RRF-120 N: 60 P2O5: 40 K2O kg ha-1; T3 to T6 -100, 75, 50 and 25% N through LMBR of the Chlorella sp., respectively; T7 to T10 -100, 75, 50 and 25% N through LMBR of Lyngbya sp., respectively. It was found that all LMBR substitution treatments were at par to RRF with respect to grain yield production. T10 gave the highest grain yield (65.16 g plant-1, which was closely followed by that (63.48 g plant-1 under T5. T10 also recorded the highest phosphorus and potassium contents in grains. T4 was markedly superior over control in terms of dry matter accumulation (DMA as well as carbohydrate content, which was ascribed to higher pigment content and photosynthetic activity in leaves. Even though considerably lower DMA was obtained in Lyngbya treatments, which might have been due to the presence of some toxic factors, no reduction in grain yield was apparent. The length of the tassel was significantly higher in either of the LMBRs at any substitution rates over RRF, except T6 and T7. The ascorbate peroxidase activity decreased with decreasing dose of Chlorella LMBR, while all the Lyngbya LMBR treatments recorded lower activity, which were at par with each other. Among the Chlorella treatments, only T5 recorded significantly higher values of glutathione reductase activity over RRF, while the rest were at par. There were significant increases in carbohydrate and crude fat, respectively, only in T4 and T3 over RRF, while no change was observed in crude protein due to LMBR treatments. Apparently, there was no

  16. Automation of a Nile red staining assay enables high throughput quantification of microalgal lipid production.

    Science.gov (United States)

    Morschett, Holger; Wiechert, Wolfgang; Oldiges, Marco

    2016-02-09

    Within the context of microalgal lipid production for biofuels and bulk chemical applications, specialized higher throughput devices for small scale parallelized cultivation are expected to boost the time efficiency of phototrophic bioprocess development. However, the increasing number of possible experiments is directly coupled to the demand for lipid quantification protocols that enable reliably measuring large sets of samples within short time and that can deal with the reduced sample volume typically generated at screening scale. To meet these demands, a dye based assay was established using a liquid handling robot to provide reproducible high throughput quantification of lipids with minimized hands-on-time. Lipid production was monitored using the fluorescent dye Nile red with dimethyl sulfoxide as solvent facilitating dye permeation. The staining kinetics of cells at different concentrations and physiological states were investigated to successfully down-scale the assay to 96 well microtiter plates. Gravimetric calibration against a well-established extractive protocol enabled absolute quantification of intracellular lipids improving precision from ±8 to ±2 % on average. Implementation into an automated liquid handling platform allows for measuring up to 48 samples within 6.5 h, reducing hands-on-time to a third compared to manual operation. Moreover, it was shown that automation enhances accuracy and precision compared to manual preparation. It was revealed that established protocols relying on optical density or cell number for biomass adjustion prior to staining may suffer from errors due to significant changes of the cells' optical and physiological properties during cultivation. Alternatively, the biovolume was used as a measure for biomass concentration so that errors from morphological changes can be excluded. The newly established assay proved to be applicable for absolute quantification of algal lipids avoiding limitations of currently established

  17. A Multi Size-Level Assessment of Benthic Marine Communities in a Coastal Environment: Are They Different Sides of the Same Coin?

    DEFF Research Database (Denmark)

    Vannini, Claudia; Volpi, Marta; Lardicci, Claudio

    2015-01-01

    Organism body size has been demonstrated to be a discriminating element in shaping the response of living beings to environmental factors, thus playing a fundamental role in community structuring. Despite the importance of studies elucidating relations among communities of different size levels...... have no (or very low) influence on the community composition at other size-levels. Moreover, each community responds in a different way to the environmental parameters and with a degree of sensitivity which seems to increase with organism size. Therefore, our data indicate that the characterization...... in ecosystems, the attempts that have been made in this sense are still very scarce and a reliable approach for these research still has to be defined. We characterized the benthic communities of bacteria, microbial eukaryotes, meiofauna and macrofauna in a coastal environment, encompassing a 10000-fold...

  18. Changes in marine fish community under influence of Leningrad nuclear power plant and another human activities in the watershed of Koporskaya Bay (Gulf of Finland, Baltic Sea)

    International Nuclear Information System (INIS)

    Zimin, V.L.

    1999-01-01

    The long-time observations (1978-1997) in the Leningrad nuclear power plant cooling water-body (Koporskaya Bay) in the frame of the Regional Ecological Monitoring Program provided reliable data on the local fish community state. Regular observations allow us to trace structural changes in fish community, because they follow changes on physiological and population levels in this community. 45 species of fishes and lamprey were recorded during all investigation period. However, the species diversity is very poor. Wittaker dominance-diversity curves reflect degradation in the coastal fish community being under influence of the complex industrial and agricultural factors. The fish community is now dominated by only 2-3 species, especially threespined stickleback and ninespined stickleback; while the first species more abundant then the second one as far as ∼10 times

  19. Oil spill effects on macrofaunal communities and bioturbation of pristine marine sediments (Caleta Valdés, Patagonia, Argentina): experimental evidence of low resistance capacities of benthic systems without history of pollution.

    Science.gov (United States)

    Ferrando, Agustina; Gonzalez, Emilia; Franco, Marcos; Commendatore, Marta; Nievas, Marina; Militon, Cécile; Stora, Georges; Gilbert, Franck; Esteves, José Luis; Cuny, Philippe

    2015-10-01

    The Patagonian coast is characterized by the existence of pristine ecosystems which may be particularly sensitive to oil contamination. In this study, a simulated oil spill at acute and chronic input levels was carried out to assess the effects of contamination on the macrobenthic community structure and the bioturbation activity of sediments sampled in Caleta Valdés creek. Superficial sediments were either noncontaminated or contaminated by Escalante crude oil and incubated in the laboratory for 30 days. Oil contamination induced adverse effects on macrobenthic community at both concentrations with, for the highest concentration, a marked decrease of approximately 40 and 55 % of density and specific richness, respectively. Besides the disappearance of sensitive species, some other species like Oligochaeta sp. 1, Paranebalia sp., and Ostracoda sp. 2 species have a higher resistance to oil contamination. Sediment reworking activity was also affected by oil addition. At the highest level of contamination, nearly no activity was observed due to the high mortality of macroorganisms. The results strongly suggest that an oil spill in this protected marine area with no previous history of contamination would have a deep impact on the non-adapted macrobenthic community.

  20. Marine habitat mapping at Labuan Marine Park, Federal Territory of Labuan, Malaysia

    Science.gov (United States)

    Mustajap, Fazliana; Saleh, Ejria; Madin, John; Hamid, Shahimah Abdul

    2015-06-01

    Marine habitat mapping has recently become essential in coastal marine science research. It is one of the efforts to understand marine ecosystems, and thus to protect them. Habitat mapping is integral to marine-related industries such as fisheries, aquaculture, forestry and tourism. An assessment of marine habitat mapping was conducted at Labuan Marine Park (LMP), a marine protected area in the Federal Territory of Labuan. It is surrounded by shallow water within its islands (Kuraman, Rusukan Kecil and Rusukan Besar) with an area of 39.7 km2. The objectives of the study are to identify the substrate and types of marine habitat present within the park. Side scan sonar (SSS) (Aquascan TM) was used to determine the substrates and habitat while ground truthings were done through field observation and SCUBA diving survey. Seabed classification and marine habitat was based on NOAA's biogeography program. Three substrate types (sand, rock, silt) were identified in this area. The major marine habitats identified are corals, macro algae and small patches of sea grass. The study area is an important refuge for spawning and juvenile fish and supports the livelihood of the coastal communities on Labuan Island. Therefore, proper management is crucial in order to better maintain the marine protected area. The findings are significant and provide detailed baseline information on marine habitat for conservation, protection and future management in LMP.

  1. Data compilations for primary production, herbivory, decomposition, and export for different types of marine communities, 1962-2002 (NODC Accession 0054500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is a compilation of published data on primary production, herbivory, and nu