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Sample records for biomasa algal asociada

  1. Harmful Algal Blooms (HABs)

    MedlinePlus

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

  2. Algal Biofuels Fact Sheet

    SciTech Connect

    2009-10-27

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

  3. Algal functional annotation tool

    Energy Science and Technology Software Center (ESTSC)

    2012-07-12

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

  4. Algal functional annotation tool

    SciTech Connect

    2012-07-12

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

  5. National Algal Biofuels Technology Roadmap

    SciTech Connect

    Ferrell, John; Sarisky-Reed, Valerie

    2010-05-01

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

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

    PubMed

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

    2011-01-01

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

  7. Algal functional annotation tool

    SciTech Connect

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

    2012-07-01

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

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

    SciTech Connect

    Not Available

    2010-09-01

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

  9. Fueling Future with Algal Genomics

    SciTech Connect

    Grigoriev, Igor

    2012-07-05

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

  10. Algal culture studies for CELSS

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

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

    PubMed

    Druehl, Louis

    2013-04-01

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

  12. Algal biofuels: challenges and opportunities.

    PubMed

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

    2013-10-01

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

  13. Algal blooms and public health

    SciTech Connect

    Epstein, P.R. . Harvard Medical School)

    1993-06-01

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

  14. Air pollutant production by algal cell cultures

    NASA Technical Reports Server (NTRS)

    Fong, F.; Funkhouser, E. A.

    1982-01-01

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

  15. Algal Flocculation with Synthetic Organic Polyelectrolytes

    PubMed Central

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

    1969-01-01

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

  16. Algal biosensor array on a single electrode.

    PubMed

    Tatsuma, Tetsu; Yoshida, Yutaka; Shitanda, Isao; Notsu, Hideo

    2009-02-01

    An algal array was prepared on a single transparent electrode, and photosynthetic activity of each algal channel and its inhibition by a toxin were monitored with a single-channel potentiostat by successive light irradiation with a LED array. PMID:19173040

  17. TEXAS HARMFUL ALGAL BLOOM COORDINATION MX964014

    EPA Science Inventory

    Harmful algal blooms (HAB) are an expanding problem in coastal Texas. Nearly � of the known harmful algal blooms along the Texas coast have occurred in the past ten years and have led to significant resource and tourism losses. For example, there are at least two types of toxic...

  18. Algal Bloom Detection from HICO

    NASA Astrophysics Data System (ADS)

    Amin, Ruhul; Gould, Richard

    2014-05-01

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

  19. Constraints to commercialization of algal fuels.

    PubMed

    Chisti, Yusuf

    2013-09-10

    Production of algal crude oil has been achieved in various pilot scale facilities, but whether algal fuels can be produced in sufficient quantity to meaningfully displace petroleum fuels, has been largely overlooked. Limitations to commercialization of algal fuels need to be understood and addressed for any future commercialization. This review identifies the major constraints to commercialization of transport fuels from microalgae. Algae derived fuels are expensive compared to petroleum derived fuels, but this could change. Unfortunately, improved economics of production are not sufficient for an environmentally sustainable production, or its large scale feasibility. A low-cost point supply of concentrated carbon dioxide colocated with the other essential resources is necessary for producing algal fuels. An insufficiency of concentrated carbon dioxide is actually a major impediment to any substantial production of algal fuels. Sustainability of production requires the development of an ability to almost fully recycle the phosphorous and nitrogen nutrients that are necessary for algae culture. Development of a nitrogen biofixation ability to support production of algal fuels ought to be an important long term objective. At sufficiently large scale, a limited supply of freshwater will pose a significant limitation to production even if marine algae are used. Processes for recovering energy from the algal biomass left after the extraction of oil, are required for achieving a net positive energy balance in the algal fuel oil. The near term outlook for widespread use of algal fuels appears bleak, but fuels for niche applications such as in aviation may be likely in the medium term. Genetic and metabolic engineering of microalgae to boost production of fuel oil and ease its recovery, are essential for commercialization of algal fuels. Algae will need to be genetically modified for improved photosynthetic efficiency in the long term. PMID:23886651

  20. Exploring the Utilization of Complex Algal Communities to Address Algal Pond Crash and Increase Annual Biomass Production for Algal Biofuels

    SciTech Connect

    Hamilton, Cyd E.

    2014-03-25

    This white paper briefly reviews the research literature exploring complex algal communities as a means of increasing algal biomass production via increased tolerance, resilience, and resistance to a variety of abiotic and biotic perturbations occurring within harvesting timescales. This paper identifies what data are available and whether more research utilizing complex communities is needed to explore the potential of complex algal community stability (CACS) approach as a plausible means to increase biomass yields regardless of ecological context and resulting in decreased algal-based fuel prices by reducing operations costs. By reviewing the literature for what we do and do not know, in terms of CACS methodologies, this report will provide guidance for future research addressing pond crash phenomena.

  1. High Frequency Monitoring for Harmful Algal Blooms

    EPA Science Inventory

    Harmful algal blooms (HABs) are increasingly becoming a significant ecologic, economic, and social driver in the use of water resources. Cyanobacteria and their toxins play an important role in management decisions for drinking water utilities and public health officials. Online ...

  2. Eukaryotic algal phytochromes span the visible spectrum.

    PubMed

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

    2014-03-11

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

  3. Direct conversion of algal biomass to biofuel

    DOEpatents

    Deng, Shuguang; Patil, Prafulla D; Gude, Veera Gnaneswar

    2014-10-14

    A method and system for providing direct conversion of algal biomass. Optionally, the method and system can be used to directly convert dry algal biomass to biodiesels under microwave irradiation by combining the reaction and combining steps. Alternatively, wet algae can be directly processed and converted to fatty acid methyl esters, which have the major components of biodiesels, by reacting with methanol at predetermined pressure and temperature ranges.

  4. Algal and fungal diversity in Antarctic lichens.

    PubMed

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

    2015-01-01

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

  5. Microflotation performance for algal separation.

    PubMed

    Hanotu, James; Bandulasena, H C Hemaka; Zimmerman, William B

    2012-07-01

    The performance of microflotation, dispersed air flotation with microbubble clouds with bubble size about 50 µm, for algae separation using fluidic oscillation for microbubble generation is investigated. This fluidic oscillator converts continuous air supply into oscillatory flow with a regular frequency to generate bubbles of the scale of the exit pore. Bubble characterization results showed that average bubble size generated under oscillatory air flow state was 86 µm, approximately twice the size of the diffuser pore size of 38 µm. In contrast, continuous air flow at the same rate through the same diffusers yielded an average bubble size of 1,059 µm, 28 times larger than the pore size. Following microbubble generation, the separation of algal cells under fluidic oscillator generated microbubbles was investigated by varying metallic coagulant types, concentration and pH. Best performances were recorded at the highest coagulant dose (150 mg/L) applied under acidic conditions (pH 5). Amongst the three metallic coagulants studied, ferric chloride yielded the overall best result of 99.2% under the optimum conditions followed closely by ferric sulfate (98.1%) and aluminum sulfate with 95.2%. This compares well with conventional dissolved air flotation (DAF) benchmarks, but has a highly turbulent flow, whereas microflotation is laminar with several orders of magnitude lower energy density. PMID:22290221

  6. Sterol phylogenesis and algal evolution

    SciTech Connect

    Nes, W.D.; Norton, R.A.; Crumley, F.G. ); Madigan, S.J.; Katz, E.R. )

    1990-10-01

    The stereochemistry of several sterol precursors and end products synthesized by two fungal-like microorganisms Prototheca wickerhamii (I) and Dictyostelium discoideum (II) have been determined by chromatographic (TLC, GLC, and HPLC) and spectral (UV, MS, and {sup 1}H NMR) methods. From I and II the following sterols were isolated from the cells: cycloartenol, cyclolaudenol, 24(28)-methylenecy-cloartanol, ergosterol, protothecasterol, 4{alpha}-methylergostanol, 4{alpha}-methylclionastanol, clionastanol, 24{beta}-ethylcholesta-8,22-enol, and dictyosterol. In addition, the mechanism of C-24 methylation was investigated in both organisms by feeding to I (2-{sup 3}H)lanosterol, (2-{sup 3}H)cycloartenol, (24{sup 3}H)lanosterol, and (methyl-{sup 2}H{sub 3})methionine and by feeding to II (methyl-{sup 2}H{sub 3})methionine. The results demonstrate that the 24{beta} configuration is formed by different alkylation routes in I and II. The authors conclude that Prototheca is an apoplastic Chlorella (i.e., an alga) and that Dictyostelium as well as the other soil amoebae that synthesize cycloartenol evolved from algal rather than fungal ancestors.

  7. Towards developing algal synthetic biology.

    PubMed

    Scaife, Mark Aden; Smith, Alison Gail

    2016-06-15

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

  8. Algal Supply System Design - Harmonized Version

    SciTech Connect

    Abodeely, Jared; Stevens, Daniel; Ray, Allison; Newby, Deborah; Schaller, Kastli

    2013-03-01

    The objective of this design report is to provide an assessment of current technologies used for production, dewatering, and converting microalgae cultivated in open-pond systems to biofuel. The original draft design was created in 2011 and has subsequently been brought into agreement with the DOE harmonized model. The design report extends beyond this harmonized model to discuss some of the challenges with assessing algal production systems, including the ability to (1) quickly assess alternative algal production system designs, (2) assess spatial and temporal variability, and (3) perform large-scale assessments considering multiple scenarios for thousands of potential sites. The Algae Logistics Model (ALM) was developed to address each of these limitations of current modeling efforts to enable assessment of the economic feasibility of algal production systems across the United States. The (ALM) enables (1) dynamic assessments using spatiotemporal conditions, (2) exploration of algal production system design configurations, (3) investigation of algal production system operating assumptions, and (4) trade-off assessments with technology decisions and operating assumptions. The report discusses results from the ALM, which is used to assess the baseline design determined by harmonization efforts between U.S. DOE national laboratories. Productivity and resource assessment data is provided by coupling the ALM with the Biomass Assessment Tool developed at PNNL. This high-fidelity data is dynamically passed to the ALM and used to help better understand the impacts of spatial and temporal constraints on algal production systems by providing a cost for producing extracted algal lipids annually for each potential site.

  9. Algal Energy Conversion and Capture

    NASA Astrophysics Data System (ADS)

    Hazendonk, P.

    2015-12-01

    We address the potential for energy conversions and capture for: energy generation; reduction in energy use; reduction in greenhouse gas emissions; remediation of water and air pollution; protection and enhancement of soil fertility. These processes have the potential to sequester carbon at scales that may have global impact. Energy conversion and capture strategies evaluate energy use and production from agriculture, urban areas and industries, and apply existing and emerging technologies to reduce and recapture energy embedded in waste products. The basis of biocrude production from Micro-algal feedstocks: 1) The nutrients from the liquid fraction of waste streams are concentrated and fed into photo bioreactors (essentially large vessels in which microalgae are grown) along with CO2 from flue gasses from down stream processes. 2) The algae are processed to remove high value products such as proteins and beta-carotenes. The advantage of algae feedstocks is the high biomass productivity is 30-50 times that of land based crops and the remaining biomass contains minimal components that are difficult to convert to biocrude. 3) The remaining biomass undergoes hydrothermal liquefaction to produces biocrude and biochar. The flue gasses of this process can be used to produce electricity (fuel cell) and subsequently fed back into the photobioreactor. The thermal energy required for this process is small, hence readily obtained from solar-thermal sources, and furthermore no drying or preprocessing is required keeping the energy overhead extremely small. 4) The biocrude can be upgraded and refined as conventional crude oil, creating a range of liquid fuels. In principle this process can be applied on the farm scale to the municipal scale. Overall, our primary food production is too dependent on fossil fuels. Energy conversion and capture can make food production sustainable.

  10. Platy algal banks: Modern and ancient

    SciTech Connect

    Brinton, L. )

    1990-05-01

    Plaly algal banks and associated cycles in the lower Ismay zone of the Paradox Formation are exposed along the walls of the San Juan River canyon, southeastern Utah. These complexes closely resemble algal bank reservoirs in the lower Ismay zone of Ismay and Cache, and possibly other Paradox basin fields. Similarities include facies relationships, lateral and vertical textural variations, and early diagenesis. Extensive algal banks exposed along the San Juan canyon generally have flat bases and mound and swale topographic surfaces, and are separated by interbank channels. The surficial mounds have a regular amplitude and wavelength suggesting a hydrologic rather than biologic influence on topography. The banks themselves, however, are believed to be thick, predominantly in-situ accumulations of platy algae. Distribution of algal banks can be mapped on a field scale; mound and swale topographic features may be identified in core on the basis of depositional and early diagenetic characteristics. Halimeda bioherms (Holocene) cover large areas behind the Great Barrier Reef, developing adjacent to the deep passes that separate the individual reefs. These large in-situ accumulations (20-50 m deep) display similar bank geometries, interbank features, topographic features, vertical textural sequence (including porosity type and distribution), and facies relationships to algal banks observed in the outcropping and subsurface Paradox Formation. Although the hydrodynamic and paleobathymetric settings differ markedly between these two examples, analogies between the mounds themselves are very close. The resemblance lends relevance to exploration and development drilling.

  11. Critical evaluation and modeling of algal harvesting using dissolved air flotation. DAF Algal Harvesting Modeling

    DOE PAGESBeta

    Zhang, Xuezhi; Hewson, John C.; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2014-07-14

    In our study, Chlorella zofingiensis harvesting by dissolved air flotation (DAF) was critically evaluated with regard to algal concentration, culture conditions, type and dosage of coagulants, and recycle ratio. Harvesting efficiency increased with coagulant dosage and leveled off at 81%, 86%, 91%, and 87% when chitosan, Al3+, Fe3+, and cetyl trimethylammonium bromide (CTAB) were used at dosages of 70, 180, 250, and 500 mg g-1, respectively. The DAF efficiency-coagulant dosage relationship changed with algal culture conditions. In evaluating the influence of the initial algal concentration and recycle ratio revealed that, under conditions typical for algal harvesting, we found that itmore » is possible that the number of bubbles is insufficient. A DAF algal harvesting model was developed to explain this observation by introducing mass-based floc size distributions and a bubble limitation into the white water blanket model. Moreover, the model revealed the importance of coagulation to increase floc-bubble collision and attachment, and the preferential interaction of bubbles with larger flocs, which limited the availability of bubbles to the smaller sized flocs. The harvesting efficiencies predicted by the model agree reasonably with experimental data obtained at different Al3+ dosages, algal concentrations, and recycle ratios. Based on this modeling, critical parameters for efficient algal harvesting were identified.« less

  12. Critical evaluation and modeling of algal harvesting using dissolved air flotation. DAF Algal Harvesting Modeling

    SciTech Connect

    Zhang, Xuezhi; Hewson, John C.; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2014-07-14

    In our study, Chlorella zofingiensis harvesting by dissolved air flotation (DAF) was critically evaluated with regard to algal concentration, culture conditions, type and dosage of coagulants, and recycle ratio. Harvesting efficiency increased with coagulant dosage and leveled off at 81%, 86%, 91%, and 87% when chitosan, Al3+, Fe3+, and cetyl trimethylammonium bromide (CTAB) were used at dosages of 70, 180, 250, and 500 mg g-1, respectively. The DAF efficiency-coagulant dosage relationship changed with algal culture conditions. In evaluating the influence of the initial algal concentration and recycle ratio revealed that, under conditions typical for algal harvesting, we found that it is possible that the number of bubbles is insufficient. A DAF algal harvesting model was developed to explain this observation by introducing mass-based floc size distributions and a bubble limitation into the white water blanket model. Moreover, the model revealed the importance of coagulation to increase floc-bubble collision and attachment, and the preferential interaction of bubbles with larger flocs, which limited the availability of bubbles to the smaller sized flocs. The harvesting efficiencies predicted by the model agree reasonably with experimental data obtained at different Al3+ dosages, algal concentrations, and recycle ratios. Based on this modeling, critical parameters for efficient algal harvesting were identified.

  13. 40 CFR 797.1050 - Algal acute toxicity test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Algistatic means having the property of inhibiting algal growth. (3) ECx means the experimentally derived chemical concentration that is calculated to effect X percent of the test criterion. (4) Growth means a relative measure of the viability of an algal population based on the number and/or weight of algal...

  14. 40 CFR 797.1050 - Algal acute toxicity test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) Algistatic means having the property of inhibiting algal growth. (3) ECx means the experimentally derived chemical concentration that is calculated to effect X percent of the test criterion. (4) Growth means a relative measure of the viability of an algal population based on the number and/or weight of algal...

  15. 40 CFR 797.1050 - Algal acute toxicity test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) Algistatic means having the property of inhibiting algal growth. (3) ECx means the experimentally derived chemical concentration that is calculated to effect X percent of the test criterion. (4) Growth means a relative measure of the viability of an algal population based on the number and/or weight of algal...

  16. Resolving Mixed Algal Species in Hyperspectral Images

    PubMed Central

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

    2014-01-01

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

  17. AL HARMFUL ALGAL BLOOM (HAB) INFORMATION EXCHANGE

    EPA Science Inventory

    This project proposes to implement an integrated web site that will serve as an Alabama Harmful Algal Bloom (HAB) Information Exchange Network. This network will be a stand-alone site where HAB data from all agencies and research efforts in the State of Alabama will be integrate...

  18. Using hyperspectral imagery to monitor algal persence

    SciTech Connect

    Anderson, J.M.; Monk, J.; Yan, Gu; Brignal, W.

    1997-08-01

    This paper illustrates how an inexpensive and easily deployable imaging spectrometer can be used to monitor and identify algal blooms at short notice, thus making practical the addition of airborne data to the usual in-situ measurements. Two examples are described, one in the Irish Sea and the other in a reservoir system in the London area.

  19. Algal production in wastewater treatment high rate algal ponds for potential biofuel use.

    PubMed

    Park, J B K; Craggs, R J

    2011-01-01

    Wastewater treatment High Rate Algal Ponds with CO2 addition could provide cost-effective and efficient tertiary-level wastewater treatment with the co-benefit of algal biomass production for biofuel use. Wastewater grown algal biomass can have a lipid content of 10-30% of dry weight, which could be used to make biodiesel. This research investigated algal biomass and total lipid production by two pilot-scale wastewater treatment HRAP(S) (4-day HRT) with and without CO2 addition under New Zealand mid summer (Nov-Jan) conditions. The influence of CO2 addition on wastewater treatment performance was also determined. CO2 was added to one of the HRAPs (the HRAP(E)) by maintaining the maximum pH of the pond below 8. Measurements of HRAP influent and effluent water qualities, total lipid content and algal biomass production were made twice a week over the experimental period. Both HRAP(S) achieved high levels of organic compound and nutrient removal, with >85% SBOD5, >92 NH4(+)-N and >70% DRP removal. Algal/bacterial biomass production in the HRAP(E) (15.2 g/m2/d) was improved by CO2 addition by approximately 30% compared with that of the control HRAP(W) (10.6 g/m2/d). Total lipid content of the biomass grown on both HRAP(S) was slightly reduced (from 25% to 20%) with CO2 addition and the maximum total lipid content of approximately 40% was observed in the HRAP(W) when low NH4(+)-N concentration (<0.5 mg/L) and high maximum pH (>10.0) occurred. Total lipid content of the biomass increased by approximately 15% under nitrogen limiting conditions, however, overall algal/bacterial biomass production was reduced by half during the period of nitrogen limitation. More research is required to maintain algal production under near nitrogen-limiting conditions. PMID:21977667

  20. Algal toxins alter copepod feeding behavior.

    PubMed

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

    2012-01-01

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

  1. Coupling of Algal Biofuel Production with Wastewater

    PubMed Central

    Panwar, Amit; Bisht, Tara Singh; Tamta, Sushma

    2014-01-01

    Microalgae have gained enormous consideration from scientific community worldwide emerging as a viable feedstock for a renewable energy source virtually being carbon neutral, high lipid content, and comparatively more advantageous to other sources of biofuels. Although microalgae are seen as a valuable source in majority part of the world for production of biofuels and bioproducts, still they are unable to accomplish sustainable large-scale algal biofuel production. Wastewater has organic and inorganic supplements required for algal growth. The coupling of microalgae with wastewater is an effective way of waste remediation and a cost-effective microalgal biofuel production. In this review article, we will primarily discuss the possibilities and current scenario regarding coupling of microalgal cultivation with biofuel production emphasizing recent progress in this area. PMID:24982930

  2. Control of algal production in a high rate algal pond: investigation through batch and continuous experiments.

    PubMed

    Derabe Maobe, H; Onodera, M; Takahashi, M; Satoh, H; Fukazawa, T

    2014-01-01

    For decades, arid and semi-arid regions in Africa have faced issues related to water availability for drinking, irrigation and livestock purposes. To tackle these issues, a laboratory scale greywater treatment system based on high rate algal pond (HRAP) technology was investigated in order to guide the operation of the pilot plant implemented in the 2iE campus in Ouagadougou (Burkina Faso). Because of the high suspended solids concentration generally found in effluents of this system, the aim of this study is to improve the performance of HRAPs in term of algal productivity and removal. To determine the selection mechanism of self-flocculated algae, three sets of sequencing batch reactors (SBRs) and three sets of continuous flow reactors (CFRs) were operated. Despite operation with the same solids retention time and the similarity of the algal growth rate found in these reactors, the algal productivity was higher in the SBRs owing to the short hydraulic retention time of 10 days in these reactors. By using a volume of CFR with twice the volume of our experimental CFRs, the algal concentration can be controlled during operation under similar physical conditions in both reactors. PMID:24960016

  3. Collection and conversion of algal lipid

    NASA Astrophysics Data System (ADS)

    Lin, Ching-Chieh

    Sustainable economic activities mandate a significant replacement of fossil energy by renewable forms. Algae-derived biofuels are increasingly seen as an alternative source of energy with potential to supplement the world's ever increasing demand. Our primary objective is, once the algae were cultivated, to eliminate or make more efficient energy-intensive processing steps of collection, drying, grinding, and solvent extraction prior to conversion. To overcome the processing barrier, we propose to streamline from cultivated algae to biodiesel via algal biomass collection by sand filtration, cell rupturing with ozone, and immediate transesterification. To collect the algal biomass, the specific Chlorococcum aquaticum suspension was acidified to pH 3.3 to promote agglomeration prior to sand filtration. The algae-loaded filter bed was drained of free water and added with methanol and ozonated for 2 min to rupture cell membrane to accelerate release of the cellular contents. The methanol solution now containing the dissolved lipid product was collected by draining, while the filter bed was regenerated by further ozonation when needed. The results showed 95% collection of the algal biomass from the suspension and a 16% yield of lipid from the algae, as well as restoration of filtration velocity of the sand bed via ozonation. The results further showed increased lipid yield upon cell rupturing and transesterified products composed entirely of fatty acid methyl ester (FAME) compounds, demonstrating that the rupture and transesterification processes could proceed consecutively in the same medium, requiring no separate steps of drying, extraction, and conversion. The FAME products from algae without exposure to ozone were mainly of 16 to 18 carbons containing up to 3 double bonds, while those from algae having been ozonated were smaller, highly saturated hydrocarbons. The new technique streamlines individual steps from cultivated algal lipid to transesterified products and

  4. Liquid transportation fuels from algal oils

    NASA Astrophysics Data System (ADS)

    Chen, Daichuan

    Liquid transportation fuels from renewable sources are becoming more prominent and important in modem society. Processing of hydrocarbon oils from algae has not been studied in detail in the past, so components which have been proposed for incorporation in algal oils via genetic engineering, such as cuparene, farnesene, phytol and squalene, have been subjected to processing via catalytic cracking in a pulse reactor at different temperatures. The cracking results showed that liquid products contained numerous high octane molecules which make it feasible for use in automobiles. Additionally, canola oil, chosen as an algal oil model compound, was studied as a feed for catalytic cracking in a fixed-bed reactor at atmospheric pressure over different types of zeolites. The results showed that MFI catalysts gave the highest yield of gasoline range products and lowest coke formation. Gallium loaded MFI zeolites increased the total aromatics yield for the canola oil cracking relative to the acid form of the zeolite. Finally, algal oils were cracked on several selected zeolites, and the results showed the same trend as canola oil cracking. MFI gave the highest gasoline yield (43.8 wt%) and lowest coke (4.7 wt%). The total aromatics yield from algae oil cracking is improved 7.8 wt% when MFI is loaded with gallium.

  5. Algal taxonomy: a road to nowhere?

    PubMed

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

    2013-04-01

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

  6. 40 CFR 797.1050 - Algal acute toxicity test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and sterilization. New test containers may contain substances which inhibit growth of algae. They.... (A) Formulation and sterilization of nutrient medium used for algal culture and preparation of...

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

    SciTech Connect

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

    2010-04-01

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

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

    USGS Publications Warehouse

    Porter, Stephen D.

    2008-01-01

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

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

    PubMed

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

    2013-01-01

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

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

    SciTech Connect

    Not Available

    2011-10-01

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

  11. 40 CFR 797.1050 - Algal acute toxicity test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 32 2014-07-01 2014-07-01 false Algal acute toxicity test. 797.1050 Section 797.1050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT (CONTINUED) ENVIRONMENTAL EFFECTS TESTING GUIDELINES Aquatic Guidelines § 797.1050 Algal acute toxicity test. (a) Purpose. The...

  12. What is causing the harmful algal blooms in Lake Erie?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harmful and nuisance algal blooms have been increasing in size and extent since about 2000. In recent years, the release of the algal toxin microcystin has become a growing concern and has resulted in the inability to use water from Lake Erie as a drinking water source to the 400,000 residents of T...

  13. COMPARISON OF LARGE RIVER SAMPLING METHODS ON ALGAL METRICS

    EPA Science Inventory

    We compared the results of four methods used to assess the algal communities at 60 sites distributed among four rivers. Based on Principle Component Analysis of physical habitat data collected concomitantly with the algal data, sites were separated into those with a mean thalweg...

  14. Algal Lipid Extraction and Upgrading to Hydrocarbons Technology Pathway

    SciTech Connect

    Davis, R.; Biddy, M.; Jones, S.

    2013-03-01

    This technology pathway case investigates the cultivation of algal biomass followed by further lipid extraction and upgrading to hydrocarbon biofuels. Technical barriers and key research needs have been assessed in order for the algal lipid extraction and upgrading pathway to be competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks.

  15. EFFECTS OF MARINE ALGAL TOXINS ON THERMOREGULATION IN MICE.

    EPA Science Inventory

    Hypothermia is often seen in mice and rats exposed acutely to marine algal toxins, but the mechanism of action of these toxins on thermoregulation is not well understood. Our laboratory has assessed the thermoregulatory mechanisms of two marine algal toxins, maitotoxin and brevet...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. Method and system of culturing an algal mat

    SciTech Connect

    Das, Keshav C; Cannon, Benjamin R; Bhatnagar, Ashish; Chinnasamy, Senthil

    2014-05-13

    A system and method for culturing algae are presented. The system and method utilize a fog of growth medium that is delivered to an algal mat generator along with a stream of CO.sub.2 to promote growth of algal cells contained in the generator.

  18. Luminescent Solar Concentrators in the Algal Industry

    NASA Astrophysics Data System (ADS)

    Hellier, Katie; Corrado, Carley; Carter, Sue; Detweiler, Angela; Bebout, Leslie

    2013-03-01

    Today's industry for renewable energy sources and highly efficient energy management systems is rapidly increasing. Development of increased efficiency Luminescent Solar Concentrators (LSCs) has brought about new applications for commercial interests, including greenhouses for agricultural crops. This project is taking first steps to explore the potential of LSCs to enhance production and reduce costs for algae and cyanobacteria used in biofuels and nutraceuticals. This pilot phase uses LSC filtered light for algal growth trials in greenhouses and laboratory experiments, creating specific wavelength combinations to determine effects of discrete solar light regimes on algal growth and the reduction of heating and water loss in the system. Enhancing the optimal spectra for specific algae will not only increase production, but has the potential to lessen contamination of large scale production due to competition from other algae and bacteria. Providing LSC filtered light will reduce evaporation and heating in regions with limited water supply, while the increased energy output from photovoltaic cells will reduce costs of heating and mixing cultures, thus creating a more efficient and cost effective production system.

  19. Mechanical algal disruption for efficient biodiesel extraction

    NASA Astrophysics Data System (ADS)

    Krehbiel, Joel David

    Biodiesel from algae provides several benefits over current biodiesel feedstocks, but the energy requirements of processing algae into a useable fuel are currently so high as to be prohibitive. One route to improving this is via disruption of the cells prior to lipid extraction, which can significantly increase energy recovery. Unfortunately, several obvious disruption techniques require more energy than can be gained. This dissertation examines the use of microbubbles to improve mechanical disruption of algal cells using experimental, theoretical, and computational methods. New laboratory experiments show that effective ultrasonic disruption of algae is achieved by adding microbubbles to an algal solution. The configuration studied flows the solution through a tube and insonifies a small section with a high-pressure ultrasound wave. Previous biomedical research has shown effective cell membrane damage on animal cells with similar methods, but the present research is the first to extend such study to algal cells. Results indicate that disruption increases with peak negative pressure between 1.90 and 3.07 MPa and with microbubble concentration up to 12.5 x 107 bubbles/ml. Energy estimates of this process suggest that it requires only one-fourth the currently most-efficient laboratory-scale disruption process. Estimates of the radius near each bubble that causes disruption (i.e. the disruption radius) suggest that it increases with peak negative pressure and is near 9--20 microm for all cases tested. It is anticipated that these procedures can be designed for better efficiency and efficacy, which will be facilitated by identifying the root mechanisms of the bubble-induced disruption. We therefore examine whether bubble expansion alone creates sufficient cell deformation for cell rupture. The spherically-symmetric Marmottant model for bubble dynamics allows estimation of the flow regime under experimental conditions. Bubble expansion is modeled as a point source of

  20. Mechanical algal disruption for efficient biodiesel extraction

    NASA Astrophysics Data System (ADS)

    Krehbiel, Joel David

    Biodiesel from algae provides several benefits over current biodiesel feedstocks, but the energy requirements of processing algae into a useable fuel are currently so high as to be prohibitive. One route to improving this is via disruption of the cells prior to lipid extraction, which can significantly increase energy recovery. Unfortunately, several obvious disruption techniques require more energy than can be gained. This dissertation examines the use of microbubbles to improve mechanical disruption of algal cells using experimental, theoretical, and computational methods. New laboratory experiments show that effective ultrasonic disruption of algae is achieved by adding microbubbles to an algal solution. The configuration studied flows the solution through a tube and insonifies a small section with a high-pressure ultrasound wave. Previous biomedical research has shown effective cell membrane damage on animal cells with similar methods, but the present research is the first to extend such study to algal cells. Results indicate that disruption increases with peak negative pressure between 1.90 and 3.07 MPa and with microbubble concentration up to 12.5 x 107 bubbles/ml. Energy estimates of this process suggest that it requires only one-fourth the currently most-efficient laboratory-scale disruption process. Estimates of the radius near each bubble that causes disruption (i.e. the disruption radius) suggest that it increases with peak negative pressure and is near 9--20 microm for all cases tested. It is anticipated that these procedures can be designed for better efficiency and efficacy, which will be facilitated by identifying the root mechanisms of the bubble-induced disruption. We therefore examine whether bubble expansion alone creates sufficient cell deformation for cell rupture. The spherically-symmetric Marmottant model for bubble dynamics allows estimation of the flow regime under experimental conditions. Bubble expansion is modeled as a point source of

  1. Evaluation of anticoagulant activity of two algal polysaccharides.

    PubMed

    Faggio, C; Pagano, M; Dottore, A; Genovese, G; Morabito, M

    2016-09-01

    Marine algae are important sources of phycocolloids like agar, carrageenans and alginates used in industrial applications. Algal polysaccharides have emerged as an important class of bioactive products showing interesting properties. The aim of our study was to evaluate the potential uses as anticoagulant drugs of algal sulphate polysaccharides extracted from Ulva fasciata (Chlorophyta) and Agardhiella subulata (Rhodophyta) collected in Ganzirri Lake (Cape Peloro Lagoon, north-eastern Sicily, Italy). Toxicity of algal extracts through trypan blue test and anticoagulant action measured by activated partial thromboplastin time (APTT), prothrombin time (PT) test has been evaluated. Algal extracts showed to prolong the PT and APTT during the coagulation cascade and to avoid the blood coagulation of samples. Furthermore, the algal extracts lack toxic effects towards cellular metabolism and their productions are relatively at low cost. This permits to consider the algae as the biological source of the future. PMID:26360806

  2. Uniform algal growth in photobioreactors using surface scatterers

    NASA Astrophysics Data System (ADS)

    Ahsan, Syed S.; Pereyra, Brandon; Erickson, David

    2014-03-01

    Cultures of algae, such as cyanobacteria, are a promising source of renewable energy. However, algal growth is highly dependent on light intensity and standard photobioreactors do a poor job of distributing light uniformly for algal utilization due to shading effects in dense algal cultures. Engineered scattering schemes are already employed in current slab-waveguide technologies, like edge-lit LEDs. Stacking such slab-waveguides that uniformly distribute light could potentially yield photobioreactors to overcome the shading effect and grow extremely high densities of algal cultures that would lower monetary and energetic costs. Here, we characterize and design a scattering scheme for specific application within photobioreactors which employs a gradient distribution of surface scatterers with uniform lateral scattering intensity. This uniform scattering scheme is shown to be superior for algal cultivation.

  3. The contribution of bacteria to algal growth by carbon cycling.

    PubMed

    Bai, Xue; Lant, Paul; Pratt, Steven

    2015-04-01

    Algal mass production in open systems is often limited by the availability of inorganic carbon substrate. In this paper, we evaluate how bacterial driven carbon cycling mitigates carbon limitation in open algal culture systems. The contribution of bacteria to carbon cycling was determined by quantifying algae growth with and without supplementation of bacteria. It was found that adding heterotrophic bacteria to an open algal culture dramatically enhanced algae productivity. Increases in algal productivity due to supplementation of bacteria of 4.8 and 3.4 times were observed in two batch tests operating at two different pH values over 7 days. A kinetic model is proposed which describes carbon limited algal growth, and how the limitation could be overcome by bacterial activity to re-mineralize photosynthetic end products. PMID:25312046

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

    NASA Astrophysics Data System (ADS)

    Alawadi, Fahad

    2010-10-01

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

  5. ALGAL NUTRIENT AVAILABILITY AND LIMITATION IN LAKE ONTARIO DURING IFYGL. PART III. ALGAL NUTRIENT LIMITATION IN LAKE ONTARIO DURING IFYGL

    EPA Science Inventory

    This study was conducted on the potential significance of nitrogen, phosphorus and micronutrients in limiting planktonic algal growth in Lake Ontario and its major tributaries. Standard algal assay procedures were used. Samples of the open waters of Lake Ontario and Niagara River...

  6. Algal productivity modeling: a step toward accurate assessments of full-scale algal cultivation.

    PubMed

    Béchet, Quentin; Chambonnière, Paul; Shilton, Andy; Guizard, Guillaume; Guieysse, Benoit

    2015-05-01

    A new biomass productivity model was parameterized for Chlorella vulgaris using short-term (<30 min) oxygen productivities from algal microcosms exposed to 6 light intensities (20-420 W/m(2)) and 6 temperatures (5-42 °C). The model was then validated against experimental biomass productivities recorded in bench-scale photobioreactors operated under 4 light intensities (30.6-74.3 W/m(2)) and 4 temperatures (10-30 °C), yielding an accuracy of ± 15% over 163 days of cultivation. This modeling approach addresses major challenges associated with the accurate prediction of algal productivity at full-scale. Firstly, while most prior modeling approaches have only considered the impact of light intensity on algal productivity, the model herein validated also accounts for the critical impact of temperature. Secondly, this study validates a theoretical approach to convert short-term oxygen productivities into long-term biomass productivities. Thirdly, the experimental methodology used has the practical advantage of only requiring one day of experimental work for complete model parameterization. The validation of this new modeling approach is therefore an important step for refining feasibility assessments of algae biotechnologies. PMID:25502920

  7. Harmful Algal Blooms and Public Health

    PubMed Central

    Grattan, Lynn M.; Holobaugh, Sailor; Morris, J. Glenn

    2015-01-01

    The five most commonly recognized Harmful Algal Bloom related illnesses include Ciguatera poisoning, Paralytic Shellfish poisoning, Neurotoxin Shellfish poisoning, Diarrheic Shellfish Poisoning and Amnesic Shellfish poisoning. Although they are each the product of different toxins, toxin assemblages or HAB precursors these clinical syndromes have much in common. Exposure occurs through the consumption of fish or shellfish; routine clinical tests are not available for diagnosis; there is no known antidote for exposure; and the risk of these illnesses can negatively impact local fishing and tourism industries. Thus, illness prevention is of paramount importance to minimize human and public health risks. To accomplish this, close communication and collaboration is needed among HAB scientists, public health researchers and local, state and tribal health departments at academic, community outreach, and policy levels. PMID:27616971

  8. Extreme Algal Bloom Detection with MERIS

    NASA Astrophysics Data System (ADS)

    Amin, R.; Gilerson, A.; Gould, R.; Arnone, R.; Ahmed, S.

    2009-05-01

    Harmful Algal Blooms (HAB's) are a major concern all over the world due to their negative impacts on the marine environment, human health, and the economy. Their detection from space still remains a challenge particularly in turbid coastal waters. In this study we propose a simple reflectance band difference approach for use with Medium Resolution Imaging Spectrometer (MERIS) data to detect intense plankton blooms. For convenience we label this approach as the Extreme Bloom Index (EBI) which is defined as EBI = Rrs (709) - Rrs (665). Our initial analysis shows that this band difference approach has some advantages over the band ratio approaches, particularly in reducing errors due to imperfect atmospheric corrections. We also do a comparison between the proposed EBI technique and the Maximum Chlorophyll Index (MCI) Gower technique. Our preliminary result shows that both the EBI and MCI indeces detect intense plankton blooms, however, MCI is more vulnerable in highly scattering waters, giving more positive false alarms than EBI.

  9. Stability of alginate-immobilized algal cells

    SciTech Connect

    Dainty, A.L.; Goulding, K.H.; Robinson, P.K.; Simpkins, I; Trevan, M.D.

    1986-01-01

    Investigations were carried out using immobilized Chlorella cells to determine the diameter, compressibility, tolerance to phosphate chelation, and ability to retain algal cells during incubation of various alginate beads. These physical bead-characteristics were affected by a variety of interactive factors, including multivalent cation type (hardening agent) and cell, cation, and alginate concentration, the latter exhibiting a predominant influence. The susceptibility of alginate beads to phosphate chelation involved a complex interaction of cation type, concentration, and pH of phosphate solution. A scale of response ranging from gel swelling to gel shrinking was observed for a range of conditions. However, stable Ca alginate beads were maintained in incubation media with a pH of 5.5 and a phosphate concentration of 5 micro M. A preliminary investigation into cell leakage from the beads illustrated the importance of maintaining a stable gel structure and limiting cell growth to reduce leakage.

  10. Production of biofuel using molluscan pseudofeces derived from algal cells

    SciTech Connect

    Das, Keshav C.; Chinnasamy, Senthil; Shelton, James; Wilde, Susan B.; Haynie, Rebecca S.; Herrin, James A.

    2012-08-28

    Embodiments of the present disclosure provide for novel strategies to harvest algal lipids using mollusks which after feeding algae from the growth medium can convert algal lipids into their biomass or excrete lipids in their pseudofeces which makes algae harvesting energy efficient and cost effective. The bioconverter, filter-feeding mollusks and their pseudofeces can be harvested and converted to biocrude using an advanced thermochemical liquefaction technology. Methods, systems, and materials are disclosed for the harvest and isolation of algal lipids from the mollusks, molluscan feces and molluscan pseudofeces.

  11. Airborne Monitoring of Harmful Algal Blooms over Lake Erie

    NASA Technical Reports Server (NTRS)

    Tokars, Roger; Lekki, John

    2013-01-01

    The Hyperspectral Imager mounted to an aircraft was used to develop a remote sensing capability to detect the pigment Phycocyanin, an indicator of Microcystis, in low concentration as an early indicator of harmful algal bloom prediction.

  12. ORGANOHALIDE FORMATION ON CHLORINATION OF ALGAL EXTRACELLULAR PRODUCTS

    EPA Science Inventory

    When certain chemical and physical parameters were controlled during chlorination of algal extracellular products (ECP), organohalide formation was modified. In general, decreases in temperature and contact time decreased the generation of purgeable (POX), nonpurgeable (NPOX), an...

  13. A seasnake's colour affects its susceptibility to algal fouling

    PubMed Central

    Shine, R.; Brischoux, F.; Pile, A. J.

    2010-01-01

    Evolutionary transitions from terrestrial to aquatic life modify selective forces on an animal's coloration. For example, light penetrates differently through water than air, and a new suite of predators and visual backgrounds changes the targets of selection. We suggest that an aquatic animal's coloration may also affect its susceptibility to algal fouling. In a colour-polymorphic field population of seasnakes (Emydocephalus annulatus) in New Caledonia, black individuals supported higher algal cover than did banded conspecifics. In experimental tests, black snake models (plastic tubes) accumulated more algae than did banded models. Algal cover substantially reduced snake activity (in the field) and swimming speeds (in the laboratory). Effects of algal cover on a snake's hydrodynamic efficiency and/or its rate of cutaneous gas exchange thus may impose selection on the colours of aquatic organisms. PMID:20375055

  14. Algal Biofuels R&D at NREL (Brochure)

    SciTech Connect

    Not Available

    2012-09-01

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

  15. Oligotrophic Bacteria Enhance Algal Growth under Iron-Deficient Conditions

    PubMed Central

    Keshtacher-Liebso..., E.; Hadar, Y.; Chen, Y.

    1995-01-01

    A Halomonas sp., a marine halophilic and oligotrophic bacterium, was grown on exudates of Dunaliella bardawil. The bacteria increased the solubility of Fe, thereby enhancing its availability to the algae. As a result, the algal growth rate increased. Because of these syntrophic relations, growth of the marine alga D. bardawil was facilitated at Fe levels that would otherwise induce Fe deficiency and inhibit algal growth. PMID:16535058

  16. The algal lift: Buoyancy-mediated sediment transport

    NASA Astrophysics Data System (ADS)

    Mendoza-Lera, Clara; Federlein, Laura L.; Knie, Matthias; Mutz, Michael

    2016-01-01

    The role of benthic algae as biostabilizers of sediments is well-known, however, their potential to lift and transport sediments remains unclear. Under low-flow conditions, matured algal mats may detach from the bed and may lift up sediment, thereby causing disturbance to the uppermost streambed sediment. We tested the potential of algal mats to lift sediments in 12 indoor flumes filled with sand (0.2 - 0.8 mm), gravel (2 - 8 mm) or a sand-gravel mixture (25/75% mass). After four weeks, the algal mats covered about 50% of the flumes area. Due to the accumulation of oxygen gas bubbles in the mats, that developed from high primary production at 4.5 weeks, about half of the algal mats detached from the bed carrying entangled sediments. Both the area covered by algal mats and detached area were similar among sediment types, but the amount of sediment transported tended to be higher for sand and sand-gravel mixture compared to gravel. Our results reveal that biologically mediated sediment transport mainly depends on the development of a dense filamentous algal matrix, that traps gas bubbles, increasing the mats buoyancy. This novel mechanism of sediment transport will occur in shallow ecosystems during low-flow periods, with the highest impact for sandy sediments.

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

    SciTech Connect

    Samson, R.; LeDuy, A.

    1982-08-01

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

  18. The ins and outs of algal metal transport

    PubMed Central

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

    2012-01-01

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

  19. Harmful algal bloom smart device application: using image analysis and machine learning techniques for early classification of harmful algal blooms

    EPA Science Inventory

    The Ecological Stewardship Institute at Northern Kentucky University and the U.S. Environmental Protection Agency are collaborating to optimize a harmful algal bloom detection algorithm that estimates the presence and count of cyanobacteria in freshwater systems by image analysis...

  20. Biodegradation of bisphenol A by an algal-bacterial system.

    PubMed

    Eio, Er Jin; Kawai, Minako; Niwa, Chiaki; Ito, Masato; Yamamoto, Shuichi; Toda, Tatsuki

    2015-10-01

    The degradation of bisphenol A (BPA) by Chlorella sorokiniana and BPA-degrading bacteria was investigated. The results show that BPA was partially removed by a monoculture of C. sorokiniana, but the remaining BPA accounted for 50.2, 56.1, and 60.5 % of the initial BPA concentrations of 10, 20, and 50 mg L(-1), respectively. The total algal BPA adsorption and accumulation were less than 1 %. C. sorokiniana-bacterial system effectively removed BPA with photosynthetic oxygen provided by the algae irrespective of the initial BPA concentration. The growth of C. sorokiniana in the algal system was inhibited by BPA concentrations of 20 and 50 mg L(-1), but not in the algal-bacterial system. This observation indicates that bacterial growth in the algal-bacterial system reduced the BPA-inhibiting effect on algae. A total of ten BPA biodegradation intermediates were identified by GC-MS. The concentrations of the biodegradation intermediates decreased to a low level at the end of the experiment. The hypothetical carbon mass balance analysis showed that the amounts of oxygen demanded by the bacteria are insufficient for effective BPA degradation. However, adding an external carbon source could compensate for the oxygen shortage. This study demonstrates that the algal-bacterial system has the potential to remove BPA and its biodegradation intermediates. PMID:26013738

  1. Design of algal film photobioreactors: material surface energy effects on algal film productivity, colonization and lipid content.

    PubMed

    Genin, Scott N; Stewart Aitchison, J; Grant Allen, D

    2014-03-01

    A parallel plate air lift reactor was used to examine the growth kinetics of mixed culture algal biofilms grown on various materials (acrylic, glass, polycarbonate, polystyrene and cellulose acetate). The growth kinetics of the algal biofilms were non-linear overall and their overall productivities ranged from 1.10-2.08g/m(2)day, with those grown on cellulose acetate having the highest productivity. Overall algal biofilm productivity was largely explained by differences in the colonization time which in turn was strongly correlated to the polar surface energy of the material, but weakly correlated to water-material contact angle. When colonization time was taken into account, the productivity for all materials except acrylic was not significantly different at approximately 2g/m(2)/day. Lipid content of the algal biofilms ranged from 6% to 8% (w/w) and was not correlated to water-material contact angle or polar surface energy. The results have potential application for selecting appropriate materials for algal film photobioreactors. PMID:24441594

  2. Consortium for Algal Biofuel Commercialization (CAB-COMM) Final Report

    SciTech Connect

    Mayfield, Stephen P.

    2015-12-04

    The Consortium for Algal Biofuel Commercialization (CAB-Comm) was established in 2010 to conduct research to enable commercial viability of alternative liquid fuels produced from algal biomass. The main objective of CAB-Comm was to dramatically improve the viability of algae as a source of liquid fuels to meet US energy needs, by addressing several significant barriers to economic viability. To achieve this goal, CAB-Comm took a diverse set of approaches on three key aspects of the algal biofuels value chain: crop protection; nutrient utilization and recycling; and the development of genetic tools. These projects have been undertaken as collaboration between six academic institutions and two industrial partners: University of California, San Diego; Scripps Institution of Oceanography; University of Nebraska, Lincoln; Rutgers University; University of California, Davis; Johns Hopkins University; Sapphire Energy; and Life Technologies.

  3. Algal lectins as promising biomolecules for biomedical research.

    PubMed

    Singh, Ram Sarup; Thakur, Shivani Rani; Bansal, Parveen

    2015-02-01

    Lectins are natural bioactive ubiquitous proteins or glycoproteins of non-immune response that bind reversibly to glycans of glycoproteins, glycolipids and polysaccharides possessing at least one non-catalytic domain causing agglutination. Some of them consist of several carbohydrate-binding domains which endow them with the properties of cell agglutination or precipitation of glycoconjugates. Lectins are rampant in nature from plants, animals and microorganisms. Among microorganisms, algae are the potent source of lectins with unique properties specifically from red algae. The demand of peculiar and neoteric biologically active substances has intensified the developments on isolation and biomedical applications of new algal lectins. Comprehensively, algal lectins are used in biomedical research for antiviral, antinociceptive, anti-inflammatory, anti-tumor activities, etc. and in pharmaceutics for the fabrication of cost-effective protein expression systems and nutraceutics. In this review, an attempt has been made to collate the information on various biomedical applications of algal lectins. PMID:23855360

  4. Marine algal toxins: origins, health effects, and their increased occurrence.

    PubMed

    Van Dolah, F M

    2000-03-01

    Certain marine algae produce potent toxins that impact human health through the consumption of contaminated shellfish and finfish and through water or aerosol exposure. Over the past three decades, the frequency and global distribution of toxic algal incidents appear to have increased, and human intoxications from novel algal sources have occurred. This increase is of particular concern, since it parallels recent evidence of large-scale ecologic disturbances that coincide with trends in global warming. The extent to which human activities have contributed to their increase therefore comes into question. This review summarizes the origins and health effects of marine algal toxins, as well as changes in their current global distribution, and examines possible causes for the recent increase in their occurrence. PMID:10698729

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

    PubMed

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

    2015-05-01

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

  6. Marine algal toxins: origins, health effects, and their increased occurrence.

    PubMed Central

    Van Dolah, F M

    2000-01-01

    Certain marine algae produce potent toxins that impact human health through the consumption of contaminated shellfish and finfish and through water or aerosol exposure. Over the past three decades, the frequency and global distribution of toxic algal incidents appear to have increased, and human intoxications from novel algal sources have occurred. This increase is of particular concern, since it parallels recent evidence of large-scale ecologic disturbances that coincide with trends in global warming. The extent to which human activities have contributed to their increase therefore comes into question. This review summarizes the origins and health effects of marine algal toxins, as well as changes in their current global distribution, and examines possible causes for the recent increase in their occurrence. Images Figure 2 Figure 3 PMID:10698729

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  8. Role of gas vesicles and intra-colony spaces during the process of algal bloom formation.

    PubMed

    Zhang, Yongsheng; Zheng, Binghui; Jiang, Xia; Zheng, Hao

    2013-06-01

    Aggregation morphology, vertical distribution, and algal density were analyzed during the algal cell floating process in three environments. The role of gas vesicles and intra-colony spaces was distinguished by algal blooms treated with ultrasonic waves and high pressure. Results demonstrated that the two buoyancy providers jointly provide buoyancy for floating algal cells. The results were also confirmed by force analysis. In the simulation experiment, the buoyancy acting on algal cells was greater than its gravity at sample ports 2 and 3 of a columnar-cultivated cell vessel, and intra-colony spaces were not detected. In Taihu Lake, gas vesicle buoyancy was notably less than total algal cell gravity. Buoyancy provided by intra-colony spaces exceeded total algal cell gravity at the water surface, but not at other water depths. In the Daning River, total buoyancies provided by the two buoyancy providers were less than total algal cell gravity at different water depths. PMID:23833817

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

    USGS Publications Warehouse

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

    2008-01-01

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

  10. A simple model for forecast of coastal algal blooms

    NASA Astrophysics Data System (ADS)

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

    2007-08-01

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

  11. Mexico-U.S. Harmful Algal Bloom Monitoring Efforts

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin; Muller-Karger, Frank E.

    2008-06-01

    Workshop on Taxonomy of Harmful Algal Blooms; Veracruz, Mexico, 18-22 February 2008; A workshop on harmful algal bloom (HAB) taxonomy, sponsored by the U.S. Environmental Protection Agency (EPA) and the Department of Health of the state of Veracruz, Mexico, was held at the Aquarium of Veracruz and focused on standardizing methods to detect HABs that affect coastal waters in the Gulf of Mexico. This binational effort was established under the umbrella of the Gulf of Mexico Alliance (GOMA), initially formed in 2004 by the five U.S. Gulf states (Florida, Alabama, Mississippi, Louisiana, and Texas) with participation from U.S. federal agencies and other stakeholders.

  12. Turbulence and nutrient interactions that control benthic algal production in an engineered cultivation raceway

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flow turbulence can be a controlling factor to the growth of benthic algae, but few studies have quantified this relationship in engineered cultivation systems. Experiments were performed to understand the limiting role of turbulence to algal productivity in an algal turf scrubber for benthic algal...

  13. Summative Mass Analysis of Algal Biomass - Integration of Analytical Procedures: Laboratory Analytical Procedure (LAP)

    SciTech Connect

    Laurens, L. M. L.

    2013-12-01

    This procedure guides the integration of laboratory analytical procedures to measure algal biomass constituents in an unambiguous manner and ultimately achieve mass balance closure for algal biomass samples. Many of these methods build on years of research in algal biomass analysis.

  14. Algal bloom-associated disease outbreaks among users of freshwater lakes-United States, 2009 - 2010

    EPA Science Inventory

    Algal blooms’ are local abundances of phytoplankton – microscopic photosynthesizing aquatic organisms found in surface waters worldwide; blooms are variable temporally and spatially and frequently produce a visible algal scum on the water. Harmful algal blooms (HABs) are abundan...

  15. Effects of algal hydrolysate as reaction medium on enzymatic hydrolysis of lignocelluloses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Algal biomass has been proposed as a source of lipids and sugars for biofuel productions. However, a substantial portion of potentially valuable algal material remains as a liquid hydrolysate after sugar and lipid extractions. This study examined the effects of an algal hydrolysate on the enzymatic...

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

    PubMed

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

    2013-06-01

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

  17. Development and optimization of biofilm based algal cultivation

    NASA Astrophysics Data System (ADS)

    Gross, Martin Anthony

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

  18. Autonomous benthic algal cultivator under feedback control of ecosystem metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An autonomous and internally-controlled techno-ecological hybrid was developed that controls primary production of algae in a laboratory-scale cultivator. The technoecosystem is based on an algal turf scrubber (ATS) system that combines engineered feedback control programming with internal feedback...

  19. Automatic identification of algal community from microscopic images.

    PubMed

    Santhi, Natchimuthu; Pradeepa, Chinnaraj; Subashini, Parthasarathy; Kalaiselvi, Senthil

    2013-01-01

    A good understanding of the population dynamics of algal communities is crucial in several ecological and pollution studies of freshwater and oceanic systems. This paper reviews the subsequent introduction to the automatic identification of the algal communities using image processing techniques from microscope images. The diverse techniques of image preprocessing, segmentation, feature extraction and recognition are considered one by one and their parameters are summarized. Automatic identification and classification of algal community are very difficult due to various factors such as change in size and shape with climatic changes, various growth periods, and the presence of other microbes. Therefore, the significance, uniqueness, and various approaches are discussed and the analyses in image processing methods are evaluated. Algal identification and associated problems in water organisms have been projected as challenges in image processing application. Various image processing approaches based on textures, shapes, and an object boundary, as well as some segmentation methods like, edge detection and color segmentations, are highlighted. Finally, artificial neural networks and some machine learning algorithms were used to classify and identifying the algae. Further, some of the benefits and drawbacks of schemes are examined. PMID:24151424

  20. Studies of the effect of gibberellic acid on algal growth.

    NASA Technical Reports Server (NTRS)

    Evans, W. K.; Sorokin, C.

    1971-01-01

    The effect of gibberellic acid on exponential growth rate of four strains of Chlorella was investigated under variety of experimental conditions. In concentrations from 10 ppm to 100 ppm, gibberellic acid was shown to have no effect on Chlorella growth. In concentration of 200 ppm, gibberellic acid exerted some unfavorable effect on algal growth.

  1. Numerical simulation of an algal bloom in Dianshan Lake

    NASA Astrophysics Data System (ADS)

    Chen, Yizhong; Lin, Weiqing; Zhu, Jianrong; Lu, Shiqiang

    2016-01-01

    A hydrodynamic model and an aquatic ecology model of Dianshan Lake, Shanghai, were built using a hydrodynamic simulation module and the water quality simulation module of Delft3D, which is an integrated modelling suite offered by Deltares. The simulated water elevation, current velocity, and direction were validated with observed data to ensure the reliability of hydrodynamic model. The seasonal growth of different algae was analyzed with consideration of observed and historical data, as well as simulated results. In 2008, the dominant algae in Dianshan Lake was Bacillariophyta from February to March, while it was Chlorophyta from April to May, and Cyanophyta from July to August. In summer, the biomass of Cyanophyta grew quickly, reaching levels much higher than the peaks of Bacillariophyta and Chlorophyta. Algae blooms primarily occurred in the stagnation regions. This phenomenon indicates that water residence time can influence algal growth significantly. A longer water residence time was associated with higher algal growth. Two conclusions were drawn from several simulations: reducing the nutrients inflow had little effect on algal blooms in Dianshan Lake; however, increasing the discharge into Dianshan Lake could change the flow field characteristic and narrow the range of stagnation regions, resulting in inhibition of algal aggregation and propagation and a subsequent reduction in areas of high concentration algae.

  2. Harmful Algal Blooms and Drinking Water Treatment Research

    EPA Science Inventory

    EPA has been conducting algal bloom research at multiple facilities around Lake Erie over the past few years to help communities confront the challenge of keeping cyanobacterial toxins from reaching consumers’ taps, while minimizing the financial burden. The first goal of this re...

  3. Effects of marine algal toxins on thermoregulation in mice.

    PubMed

    Gordon, Christopher J; Ramsdell, John S

    2005-01-01

    Hypothermia is often seen in mice and rats exposed acutely to marine algal toxins, but the mechanism of action of these toxins on thermoregulation is not well understood. Our laboratory has assessed the thermoregulatory mechanisms of two marine algal toxins, maitotoxin and brevetoxin in the mouse. Radiotelemetry was used to measure core temperature in the unrestrained mouse while it was housed in a temperature gradient allowing the exhibition of thermoregulatory behavior. Both maitotoxin (338 ng/kg) and brevetoxin (180 microg/kg) were shown to elicit profound hypothermic responses accompanied by a preference for cooler ambient temperatures in the gradient. This behavioral response would suggest that the toxins alter the central neural control of body temperature, resulting in a regulated reduction in body temperature. Following recovery from the acute hypothermic effects of brevetoxin, mice developed an elevation in their daytime core temperature that persisted for several days after exposure. This fever-like response may represent a delayed toxicological effect of the marine algal toxins that is manifested through the thermoregulatory system. Overall, algal toxins have acute and delayed effects on temperature regulation in the mouse. A better understanding of the mechanisms of action of the toxins on thermoregulation should lead to improved methods for treating victims of ciguatera and other toxin exposures. PMID:16111859

  4. Toward on-line measurement of algal properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Algai is a potential soruce of large amounts of lipids for conversion to hydrocarbon fuels. Industria-scale algai production requires process control, which further requires sensors to measure critical algal properties. One of the principal properties that needs to be measured in algae production is...

  5. Mechanism of algal aggregation by Bacillus sp. strain RP1137.

    PubMed

    Powell, Ryan J; Hill, Russell T

    2014-07-01

    Alga-derived biofuels are one of the best alternatives for economically replacing liquid fossil fuels with a fungible renewable energy source. Production of fuel from algae is technically feasible but not yet economically viable. Harvest of dilute algal biomass from the surrounding water remains one of the largest barriers to economic production of algal biofuel. We identified Bacillus sp. strain RP1137 in a previous study and showed that this strain can rapidly aggregate several biofuel-producing algae in a pH- and divalent-cation-dependent manner. In this study, we further characterized the mechanism of algal aggregation by RP1137. We show that aggregation of both algae and bacteria is optimal in the exponential phase of growth and that the density of ionizable residues on the RP1137 cell surface changes with growth stage. Aggregation likely occurs via charge neutralization with calcium ions at the cell surface of both algae and bacteria. We show that charge neutralization occurs at least in part through binding of calcium to negatively charged teichoic acid residues. The addition of calcium also renders both algae and bacteria more able to bind to hydrophobic beads, suggesting that aggregation may occur through hydrophobic interactions. Knowledge of the aggregation mechanism may enable engineering of RP1137 to obtain more efficient algal harvesting. PMID:24771029

  6. Effects of solar ultraviolet radiation on tropical algal communities

    SciTech Connect

    Santas, R.

    1989-01-01

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

  7. Mechanism of Algal Aggregation by Bacillus sp. Strain RP1137

    PubMed Central

    Powell, Ryan J.

    2014-01-01

    Alga-derived biofuels are one of the best alternatives for economically replacing liquid fossil fuels with a fungible renewable energy source. Production of fuel from algae is technically feasible but not yet economically viable. Harvest of dilute algal biomass from the surrounding water remains one of the largest barriers to economic production of algal biofuel. We identified Bacillus sp. strain RP1137 in a previous study and showed that this strain can rapidly aggregate several biofuel-producing algae in a pH- and divalent-cation-dependent manner. In this study, we further characterized the mechanism of algal aggregation by RP1137. We show that aggregation of both algae and bacteria is optimal in the exponential phase of growth and that the density of ionizable residues on the RP1137 cell surface changes with growth stage. Aggregation likely occurs via charge neutralization with calcium ions at the cell surface of both algae and bacteria. We show that charge neutralization occurs at least in part through binding of calcium to negatively charged teichoic acid residues. The addition of calcium also renders both algae and bacteria more able to bind to hydrophobic beads, suggesting that aggregation may occur through hydrophobic interactions. Knowledge of the aggregation mechanism may enable engineering of RP1137 to obtain more efficient algal harvesting. PMID:24771029

  8. Biofertilizers from Algal Treatment of Dairy and Swine Manure Effluents: Characterization of Algal Biomass as a Slow Release Fertilizer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An alternative practice to land spreading of manure effluents is to grow crops of algae on the nitrogen (N) and phosphorus (P) present in these liquid slurries. The overall environmental and economic values of this approach depend, in part, on the use and value of the resulting algal byproduct. Am...

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

    PubMed

    Tootell, Jesse S; Steele, Mark A

    2016-05-01

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

  10. Connecting Florida Bay algal blooms to freshwater nutrient sources

    NASA Astrophysics Data System (ADS)

    Blakey, T.; Melesse, A. M.

    2013-12-01

    In this study, monthly water quality data collected in the Everglades by the Southeast Environmental Research Center (SERC) and the South Florida Water Management District (SFWMD) from 1991 to 2008 at 28 sampling stations distributed across Florida Bay was analyzed within the context of local geomorphology and seasonal wind and current regimes in order to evaluate the feasibility of the various purported nutrient sources for reoccurring algal blooms. The in situ chlorophyll-a (chl-a) measurements from the SERC dataset were evaluated as the indicator of algal biomass. Significant differences in average monthly chl-a concentrations at stations indicated a seasonality of algal blooms in the north central and west areas that is not evidenced in stations exhibiting low levels of chl-a throughout the typical year. Tukey's pairwise comparisons of monthly chl-a indicated, at the 95% confidence level, peak algal biomass occurs in October and November at the end of the wet season with minimums occurring between February and August depending on the location of the station. By month comparison of chl-a levels across stations suggest seasonal trends in the geographic focus and extent of blooms. Significant differences from Tukey's pairwise comparisons at the 95% confidence level showed stations to the west as having higher levels of chl-a in March through May with north central stations dominating from June to January. The month of February shows no significant difference in chl-a levels across this area. The results support hypotheses centering on a western source of nutrients that are delivered to the bay over the course of the rainy season. Mapping water quality sampling station locations on top of the bathymetry of Florida Bay illustrates the importance of considering coastal morphology in explaining trends in estuarine algal blooms. Coastal geomorphology along with seasonal changes in the direction of winds and magnitude of rains are demonstrated to be the predominant

  11. Hybrid life-cycle assessment of algal biofuel production.

    PubMed

    Malik, Arunima; Lenzen, Manfred; Ralph, Peter J; Tamburic, Bojan

    2015-05-01

    The objective of this work is to establish whether algal bio-crude production is environmentally, economically and socially sustainable. To this end, an economic multi-regional input-output model of Australia was complemented with engineering process data on algal bio-crude production. This model was used to undertake hybrid life-cycle assessment for measuring the direct, as well as indirect impacts of producing bio-crude. Overall, the supply chain of bio-crude is more sustainable than that of conventional crude oil. The results indicate that producing 1 million tonnes of bio-crude will generate almost 13,000 new jobs and 4 billion dollars' worth of economic stimulus. Furthermore, bio-crude production will offer carbon sequestration opportunities as the production process is net carbon-negative. PMID:25465782

  12. Unraveling algal lipid metabolism: Recent advances in gene identification.

    PubMed

    Khozin-Goldberg, Inna; Cohen, Zvi

    2011-01-01

    Microalgae are now the focus of intensive research due to their potential as a renewable feedstock for biodiesel. This research requires a thorough understanding of the biochemistry and genetics of these organisms' lipid-biosynthesis pathways. Genes encoding lipid-biosynthesis enzymes can now be identified in the genomes of various eukaryotic microalgae. However, an examination of the predicted proteins at the biochemical and molecular levels is mandatory to verify their function. The essential molecular and genetic tools are now available for a comprehensive characterization of genes coding for enzymes of the lipid-biosynthesis pathways in some algal species. This review mainly summarizes the novel information emerging from recently obtained algal gene identification. PMID:20709142

  13. Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

    NASA Astrophysics Data System (ADS)

    Sundareshwar, P. V.; Upadhayay, S.; Abessa, M.; Honomichl, S.; Berdanier, B.; Spaulding, S. A.; Sandvik, C.; Trennepohl, A.

    2011-05-01

    In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large “blooms” in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers.

  14. Algal Lipid Extraction and Upgrading to Hydrocarbons Technology Pathway

    SciTech Connect

    Davis, Ryan; Biddy, Mary J.; Jones, Susanne B.

    2013-03-31

    In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This technology pathway case investigates the cultivation of algal biomass followed by further lipid extraction and upgrading to hydrocarbon biofuels. Technical barriers and key research needs have been assessed in order for the algal lipid extraction and upgrading pathway to be competitive with petroleum-derived gasoline, diesel and jet range hydrocarbon blendstocks.

  15. Phenolic content and antioxidant capacity in algal food products.

    PubMed

    Machu, Ludmila; Misurcova, Ladislava; Ambrozova, Jarmila Vavra; Orsavova, Jana; Mlcek, Jiri; Sochor, Jiri; Jurikova, Tunde

    2015-01-01

    The study objective was to investigate total phenolic content using Folin-Ciocalteu's method, to assess nine phenols by HPLC, to determine antioxidant capacity of the water soluble compounds (ACW) by a photochemiluminescence method, and to calculate the correlation coefficients in commercial algal food products from brown (Laminaria japonica, Eisenia bicyclis, Hizikia fusiformis, Undaria pinnatifida) and red (Porphyra tenera, Palmaria palmata) seaweed, green freshwater algae (Chlorella pyrenoidosa), and cyanobacteria (Spirulina platensis). HPLC analysis showed that the most abundant phenolic compound was epicatechin. From spectrophotometry and ACW determination it was evident that brown seaweed Eisenia bicyclis was the sample with the highest phenolic and ACW values (193 mg·g-1 GAE; 7.53 µmol AA·g-1, respectively). A linear relationship existed between ACW and phenolic contents (r = 0.99). Some algal products seem to be promising functional foods rich in polyphenols. PMID:25587787

  16. Determination of the cyanobacterial toxin cylindrospermopsin in algal food supplements

    PubMed Central

    Liu, H.; Scott, P.M.

    2011-01-01

    For the analysis of blue–green algal food supplements for cylindrospermopsin (CYN), a C18 solid-phase extraction column and a polygraphitized carbon solid-phase extraction column in series was an effective procedure for the clean-up of extracts. Determination of CYN was by liquid chromatography with ultraviolet light detection. At extract spiking levels of CYN equivalent to 25–500 μg g−1, blue–green algal supplement recoveries were in the range 70–90%. CYN was not detected in ten samples of food supplements and one chocolate product, all containing blue–green algae. The limit of detection for the method was 16 μg g−1, and the limit of quantification was 52 μg g−1. PMID:21623503

  17. Export of algal biomass from the melting Arctic sea ice.

    PubMed

    Boetius, Antje; Albrecht, Sebastian; Bakker, Karel; Bienhold, Christina; Felden, Janine; Fernández-Méndez, Mar; Hendricks, Stefan; Katlein, Christian; Lalande, Catherine; Krumpen, Thomas; Nicolaus, Marcel; Peeken, Ilka; Rabe, Benjamin; Rogacheva, Antonina; Rybakova, Elena; Somavilla, Raquel; Wenzhöfer, Frank

    2013-03-22

    In the Arctic, under-ice primary production is limited to summer months and is restricted not only by ice thickness and snow cover but also by the stratification of the water column, which constrains nutrient supply for algal growth. Research Vessel Polarstern visited the ice-covered eastern-central basins between 82° to 89°N and 30° to 130°E in summer 2012, when Arctic sea ice declined to a record minimum. During this cruise, we observed a widespread deposition of ice algal biomass of on average 9 grams of carbon per square meter to the deep-sea floor of the central Arctic basins. Data from this cruise will contribute to assessing the effect of current climate change on Arctic productivity, biodiversity, and ecological function. PMID:23413190

  18. A Taste of Algal Genomes from the Joint Genome Institute

    SciTech Connect

    Kuo, Alan; Grigoriev, Igor

    2012-06-17

    Algae play profound roles in aquatic food chains and the carbon cycle, can impose health and economic costs through toxic blooms, provide models for the study of symbiosis, photosynthesis, and eukaryotic evolution, and are candidate sources for bio-fuels; all of these research areas are part of the mission of DOE's Joint Genome Institute (JGI). To date JGI has sequenced, assembled, annotated, and released to the public the genomes of 18 species and strains of algae, sampling almost all of the major clades of photosynthetic eukaryotes. With more algal genomes currently undergoing analysis, JGI continues its commitment to driving forward basic and applied algal science. Among these ongoing projects are the pan-genome of the dominant coccolithophore Emiliania huxleyi, the interrelationships between the 4 genomes in the nucleomorph-containing Bigelowiella natans and Guillardia theta, and the search for symbiosis genes of lichens.

  19. ALGAL NUTRIENT AVAILABILITY AND LIMITATION IN LAKE ONTARIO DURING IFYGL. APPENDICES TO PART III. ALGAL NUTRIENT LIMITATION IN LAKE ONTARIO DURING IFYGL

    EPA Science Inventory

    This study was conducted on the potential significance of nitrogen, phosphorus and micronutrients in limiting planktonic algal growth in Lake Ontario and its major tributaries. Standard algal assay procedures were used. Samples of the open waters of Lake Ontario and Niagara River...

  20. [Algal biotoxins in Dialysis Water: a risk not managed].

    PubMed

    Ferrante, Margherita; Zuccarello, Pietro; Garufi, Angela; Cristaldi, Antonio; Oliveri Conti, Gea

    2016-01-01

    A literature review was performed to retrieve updated information on the quality of dialysis water, with a focus on the emerging problem of the presence of algal toxins (microcystins) produced by cyanobacteria. Current legislation was examined as well as studies conducted to date in different geographic areas. In this article, the authors present review results along with recommendations to operators and managers of dialysis units, for preventing possible risks for patients. PMID:27077559

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

    PubMed

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

    2011-01-01

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

  2. Biological control of harmful algal blooms: A modelling study

    NASA Astrophysics Data System (ADS)

    Solé, Jordi; Estrada, Marta; Garcia-Ladona, Emilio

    2006-07-01

    A multispecies dynamic simulation model (ERSEM) was used to examine the influence of allelopathic and trophic interactions causing feeding avoidance by predators, on the formation of harmful algal blooms, under environmental scenarios typical of a Mediterranean harbour (Barcelona). The biological state variables of the model included four functional groups of phytoplankton (diatoms, toxic and non-toxic flagellates and picophytoplankton), heterotrophic flagellates, micro- and mesozooplankton and bacteria. The physical-chemical forcing (irradiance, temperature and major nutrient concentrations) was based on an actual series of measurements taken along a year cycle in the Barcelona harbour. In order to evaluate potential effects of advection, some runs were repeated after introducing a biomass loss term. Numerical simulations showed that allelopathic effects of a toxic alga on a non-toxic but otherwise similar competitor did not have appreciable influence on the dynamics of the system. However, induction of avoidance of the toxic alga by predators, which resulted on increased predation pressure on other algal groups had a significant effect on the development of algal and predator populations. The presence of advection overrided the effect of these interactions and only allowed organisms with sufficiently high potential growth rates to thrive.

  3. Micro-structured surfaces for algal biofilm growth

    NASA Astrophysics Data System (ADS)

    Sathananthan, Suthamathy; Genin, Scott N.; Aitchison, J. Stewart; Allen, D. Grant

    2013-12-01

    It is well known that cells respond to structured surface cues that are on the micro/nanometer scale. Tissue engineering and bio-fouling fields have utilized the semiconductor device fabrication processes to make micro- and nanometer patterned surfaces to study animal cell tissue formation and to prevent algae attachment on marine surfaces respectively. In this paper we describe the use of micro-structured surfaces to study the attachment and growth of algal films. This paper gives an overview of how micro-structured surfaces are made for this purpose, how they are incorporated into a photo bioreactor and how this patterning influences the growth of an algal biofilm. Our results suggest that surface patterning with deeper V-groove patterns that are of the same size scale as the algal species has resulted in higher biomass productivity giving them a chance to embed and attach on the slope and flat surfaces whereas shallower size grooves and completely flat surfaces did not show this trend.

  4. Floating ice-algal aggregates below melting arctic sea ice.

    PubMed

    Assmy, Philipp; Ehn, Jens K; Fernández-Méndez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A; Hudson, Stephen R; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H H; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef

    2013-01-01

    During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year. PMID:24204642

  5. Identifying Historical Occurrences of HABs Using Sedimentary Algal Pigments

    NASA Astrophysics Data System (ADS)

    Smoak, J. M.; Waters, M. N.

    2008-12-01

    Algal blooms are a common feature of many coastal areas. Under some environmental conditions, these develop into Harmful Algal Blooms (HABs) and present an environmental hazard and a health risk for humans and wildlife due to toxin production. While monitoring programs track the development of contemporary HABs, data are lacking for historical blooms. We use sedimentary algal pigments to identify the occurrence of Karenia Brevis (Florida Red Tide) in sediment cores collected from mangrove environments along the west coast of Florida. Karenia Brevis has a unique pigment, gyroxanthin-diester, that is routinely used to identify red tide in the water column. Gyroxanthin-diester and other carotenoid pigments associated with red tide taxa are analyzed using HPLC techniques. Identification of gyroxanthan-diester is based on comparison with HPLC analysis of gyroxanthin standard, a monoculture sample of K. Brevis and with published spectra of Gyroxanthin-diester in water samples. We track the timing of the K. Brevis using Pb-210 dating models which allows an examination over the last 100 years.

  6. Floating Ice-Algal Aggregates below Melting Arctic Sea Ice

    PubMed Central

    Assmy, Philipp; Ehn, Jens K.; Fernández-Méndez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A.; Hudson, Stephen R.; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H. H.; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef

    2013-01-01

    During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year. PMID:24204642

  7. An algal solution to large scale wastewater amelioration

    SciTech Connect

    Adey, W.H.

    1995-06-01

    Wastewater nutrients can be lowered to oligotrophic levels through uptake by algal biomass, while photosynthetic oxygen removes bacterial BOD, and oxygen-based ions, with UV application, can break down xenobiotic organic compounds. Algae also uptake heavy metals in cell walls, and the high pH from CO{sub 25} removal precipitates metals, earth metals and phosphorus. Algal biomass produced from many wastewaters has valuable commercial applications. Algal Turf Scrubbing (ATS) was developed as a tool to control water quality in ecosystem models, often at oligotrophic levels. ATS has routinely achieved biomass production (and water amelioration capability) of over 50 g (dry mass) m{sup -2} day{sup -1} in secondary sewage. Engineering innovations, with mechanized harvest, have brought ATS to large scale with a pilot sewage plant in central California. This is a low cost, modular unit, at 1000 cubic meters per day, and plans are underway to expand to city capacity for Tertiary-Quinary water recovery. A wide variety of wastewater applications, from agricultural, to aquacultural to industrial will be discussed.

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

    PubMed

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

    2016-05-01

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

  9. Variations of algal communities cause darkening of a Greenland glacier.

    PubMed

    Lutz, Stefanie; Anesio, Alexandre M; Jorge Villar, Susana E; Benning, Liane G

    2014-08-01

    We have assessed the microbial ecology on the surface of Mittivakkat glacier in SE-Greenland during the exceptional high melting season in July 2012 when the so far most extreme melting rate for the Greenland Ice Sheet has been recorded. By employing a complementary and multi-disciplinary field sampling and analytical approach, we quantified the dramatic changes in the different microbial surface habitats (green snow, red snow, biofilms, grey ice, cryoconite holes). The observed clear change in dominant algal community and their rapidly changing cryo-organic adaptation inventory was linked to the high melting rate. The changes in carbon and nutrient fluxes between different microbial pools (from snow to ice, cryoconite holes and glacial forefronts) revealed that snow and ice algae dominate the net primary production at the onset of melting, and that they have the potential to support the cryoconite hole communities as carbon and nutrient sources. A large proportion of algal cells is retained on the glacial surface and temporal and spatial changes in pigmentation contribute to the darkening of the snow and ice surfaces. This implies that the fast, melt-induced algal growth has a high albedo reduction potential, and this may lead to a positive feedback speeding up melting processes. PMID:24920320

  10. Study of cnidarian-algal symbiosis in the "omics" age.

    PubMed

    Meyer, Eli; Weis, Virginia M

    2012-08-01

    The symbiotic associations between cnidarians and dinoflagellate algae (Symbiodinium) support productive and diverse ecosystems in coral reefs. Many aspects of this association, including the mechanistic basis of host-symbiont recognition and metabolic interaction, remain poorly understood. The first completed genome sequence for a symbiotic anthozoan is now available (the coral Acropora digitifera), and extensive expressed sequence tag resources are available for a variety of other symbiotic corals and anemones. These resources make it possible to profile gene expression, protein abundance, and protein localization associated with the symbiotic state. Here we review the history of "omics" studies of cnidarian-algal symbiosis and the current availability of sequence resources for corals and anemones, identifying genes putatively involved in symbiosis across 10 anthozoan species. The public availability of candidate symbiosis-associated genes leaves the field of cnidarian-algal symbiosis poised for in-depth comparative studies of sequence diversity and gene expression and for targeted functional studies of genes associated with symbiosis. Reviewing the progress to date suggests directions for future investigations of cnidarian-algal symbiosis that include (i) sequencing of Symbiodinium, (ii) proteomic analysis of the symbiosome membrane complex, (iii) glycomic analysis of Symbiodinium cell surfaces, and (iv) expression profiling of the gastrodermal cells hosting Symbiodinium. PMID:22983032

  11. Promotion of harmful algal blooms by zooplankton predatory activity

    PubMed Central

    Mitra, Aditee; Flynn, Kevin J

    2006-01-01

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

  12. Raman microspectroscopy based sensor of algal lipid unsaturation

    NASA Astrophysics Data System (ADS)

    Samek, Ota; Pilát, Zdeněk; Jonáš, Alexandr; Zemánek, Pavel; Šerý, Mojmír; Ježek, Jan; Bernatová, Silvie; Nedbal, Ladislav; Trtílek, Martin

    2011-05-01

    Raman spectroscopy is a powerful tool for chemical analysis. This technique can elucidate fundamental questions about the metabolic processes and intercellular variability on a single cell level. Therefore, Raman spectroscopy can significantly contribute to the study and use of microalgae in systems biology and biofuel technology. Raman spectroscopy can be combined with optical tweezers. We have employed microfluidic system to deliver the sampled microalgae to the Raman-tweezers. This instrument is able to measure chemical composition of cells and to track metabolic processes in vivo, in real-time and label-free making it possible to detect population variability in a wide array of traits. Moreover, employing an active sorting switch, cells can be separated depending on input parameters obtained from Raman spectra. We focus on algal lipids which are promising potential products for biofuel as well as for nutrition. Important parameter characterizing the algal lipids is the degree of unsaturation of the constituent fatty acids. We demonstrate the capacity of our Raman tweezers based sensor to sort cells according to the degree of unsaturation in lipid storage bodies of individual living algal cells.

  13. Evaluating algal growth performance and water use efficiency of pilot-scale revolving algal biofilm (RAB) culture systems.

    PubMed

    Gross, Martin; Mascarenhas, Vernon; Wen, Zhiyou

    2015-10-01

    A Revolving Algal Biofilm (RAB) growth system in which algal cells are attached to a flexible material rotating between liquid and gas phases has been developed. In this work, different configurations of RAB systems were developed at pilot-scale by retrofitting the attachment materials to a raceway pond (2000-L with 8.5 m(2) footprint area) and a trough reservoir (150 L with 3.5 m(2) footprint area). The algal growth performance and chemical composition, as well as the water evaporative loss and specific water consumption were evaluated over a period of nine months in a greenhouse environment near Boone, Iowa USA. Additionally a raceway pond was run in parallel, which served as a control. On average the raceway-based RAB and the trough-based RAB outperformed the control pond by 309% and 697%, respectively. A maximum productivity of 46.8 g m(-2) day(-1) was achieved on the trough-based RAB system. The evaporative water loss of the RAB system was modeled based on an energy balance analysis and was experimentally validated. While the RAB system, particularly the trough-based RAB, had higher water evaporative loss, the specific water consumption per unit of biomass produced was only 26% (raceway-based RAB) and 7% (trough-based RAB) of that of the control pond. Collectively, this research shows that the RAB system is an efficient algal culture system and has great potential to commercially produce microalgae with high productivity and efficient water use. PMID:25899246

  14. Algal remediation of CO₂ and nutrient discharges: A review.

    PubMed

    Judd, Simon; van den Broeke, Leo J P; Shurair, Mohamed; Kuti, Yussuf; Znad, Hussein

    2015-12-15

    The recent literature pertaining to the application of algal photobioreactors (PBRs) to both carbon dioxide mitigation and nutrient abatement is reviewed and the reported data analysed. The review appraises the influence of key system parameters on performance with reference to (a) the absorption and biological fixation of CO2 from gaseous effluent streams, and (b) the removal of nutrients from wastewaters. Key parameters appraised individually with reference to CO2 removal comprise algal speciation, light intensity, mass transfer, gas and hydraulic residence time, pollutant (CO2 and nutrient) loading, biochemical and chemical stoichiometry (including pH), and temperature. Nutrient removal has been assessed with reference to hydraulic residence time and reactor configuration, along with C:nutrient ratios and other factors affecting carbon fixation, and outcomes compared with those reported for classical biological nutrient removal (BNR). Outcomes of the review indicate there has been a disproportionate increase in algal PBR research outputs over the past 5-8 years, with a significant number of studies based on small, bench-scale systems. The quantitative impacts of light intensity and loading on CO2 uptake are highly dependent on the algal species, and also affected by solution chemical conditions such as temperature and pH. Calculations based on available data for biomass growth rates indicate that a reactor CO2 residence time of around 4 h is required for significant CO2 removal. Nutrient removal data indicate residence times of 2-5 days are required for significant nutrient removal, compared with <12 h for a BNR plant. Moreover, the shallow depth of the simplest PBR configuration (the high rate algal pond, HRAP) means that its footprint is at least two orders of magnitude greater than a classical BNR plant. It is concluded that the combined carbon capture/nutrient removal process relies on optimisation of a number of process parameters acting synergistically

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

    PubMed

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

    2008-06-01

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

  16. Effect of centrifugation on water recycling and algal growth to enable algae biodiesel production.

    PubMed

    Igou, Thomas; Van Ginkel, Steven W; Penalver-Argueso, Patricia; Fu, Hao; Doi, Shusuke; Narode, Asmita; Cheruvu, Sarasija; Zhang, Qian; Hassan, Fariha; Woodruff, Frazier; Chen, Yongsheng

    2014-12-01

    The latest research shows that algal biofuels, at the production levels mandated in the Energy Independence and Security Act of 2007, will place significant demands on water and compete with agriculture meant for food production. Thus, there is a great need to recycle water while producing algal biofuels. This study shows that when using a synthetic medium, soluble algal products, bacteria, and other inhibitors can be removed by centrifugation and enable water recycling. Average water recovery reached 84% and water could be recycled at least 10 times without reducing algal growth. PMID:25654935

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

    PubMed

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

    2014-10-01

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

  18. Pyrolysis Strategies for Effective Utilization of Lignocellulosic and Algal Biomass

    NASA Astrophysics Data System (ADS)

    Maddi, Balakrishna

    Pyrolysis is a processing technique involving thermal degradation of biomass in the absence of oxygen. The bio-oils obtained following the condensation of the pyrolysis vapors form a convenient starting point for valorizing the major components of lignocellulosic as well as algal biomass feed stocks for the production of fuels and value-added chemicals. Pyrolysis can be implemented on whole biomass or on residues left behind following standard fractionation methods. Microalgae and oil seeds predominantly consist of protein, carbohydrate and triglycerides, whereas lignocellulose is composed of carbohydrates (cellulose and hemicellulose) and lignin. The differences in the major components of these two types of biomass will necessitate different pyrolysis strategies to derive the optimal benefits from the resulting bio-oils. In this thesis, novel pyrolysis strategies were developed that enable efficient utilization of the bio-oils (and/or their vapors) from lignocellulose, algae, as well as oil seed feed stocks. With lignocellulosic feed stocks, pyrolysis of whole biomass as well as the lignin residue left behind following well-established pretreatment and saccharification (i.e., depolymerization of cellulose and hemicellulose to their monomeric-sugars) of the biomass was studied with and without catalysts. Following this, pyrolysis of (lipid-deficient) algae and lignocellulosic feed stocks, under similar reactor conditions, was performed for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from

  19. Estimates of nuclear DNA content in red algal lineages

    PubMed Central

    Kapraun, Donald F.; Freshwater, D. Wilson

    2012-01-01

    Background and aims The red algae are an evolutionarily ancient group of predominantly marine organisms with an estimated 6000 species. Consensus higher-level molecular phylogenies support a basal split between the unicellular Cyanidiophytina and morphologically diverse Rhodophytina, the later subphylum containing most red algal species. The Rhodophytina is divided into six classes, of which five represent early diverging lineages of generally uninucleate species, whose evolutionary relationships are poorly resolved. The remaining species compose the large (27 currently recognized orders), morphologically diverse and typically multinucleate Florideophyceae. Nuclear DNA content estimates have been published for <1 % of the described red algae. The present investigation summarizes the state of our knowledge and expands our coverage of DNA content information from 196 isolates of red algae. Methodology The DNA-localizing fluorochrome DAPI (4′,6-diamidino-2-phenylindole) and RBC (chicken erythrocytes) standards were used to estimate 2C values with static microspectrophotometry. Principal results Nuclear DNA contents are reported for 196 isolates of red algae, almost doubling the number of estimates available for these organisms. Present results also confirm the reported DNA content range of 0.1–2.8 pg, with species of Ceramiales, Nemaliales and Palmariales containing apparently polyploid genomes with 2C = 2.8, 2.3 and 2.8 pg, respectively. Conclusions Early diverging red algal lineages are characterized by relatively small 2C DNA contents while a wide range of 2C values is found within the derived Florideophyceae. An overall correlation between phylogenetic placement and 2C DNA content is not apparent; however, genome size data are available for only a small portion of red algae. Current data do support polyploidy and aneuploidy as pervasive features of red algal genome evolution. PMID:22479676

  20. Assessment of Algal Farm Designs Using a Dynamic Modular Approach

    SciTech Connect

    Abodeely, Jared; Coleman, Andre M.; Stevens, Daniel M.; Ray, Allison E.; Cafferty, Kara G.; Newby, Deborah T.

    2014-07-01

    The notion of renewable energy provides an important mechanism for diversifying an energy portfolio, which ultimately would have numerous benefits including increased energy resilience, reduction of foreign energy supplies, reduced GHG emissions, development of a green energy sector that contributes to economic growth, and providing a sustainable energy supply. The conversion of autotrophic algae to liquid transportation fuels is the basis of several decades of research to competitively bring energy-scale production into reality; however, many challenges still remain for making algal biofuels economically viable. Addressing current challenges associated with algal production systems, in part, requires the ability to assess spatial and temporal variability, rapidly evaluate alternative algal production system designs, and perform large-scale assessments considering multiple scenarios for thousands of potential sites. We introduce the Algae Logistics Model (ALM) which helps to address these challenges. The flexible nature of the ALM architecture allows the model to: 1) interface with external biomass production and resource assessment models, as well as other relevant datasets including those with spatiotemporal granularity; 2) interchange design processes to enable operational and economic assessments of multiple design configurations, including the integration of current and new innovative technologies; and 3) conduct trade-off analysis to help understand the site-specific techno-economic trade-offs and inform technology decisions. This study uses the ALM to investigate a baseline open-pond production system determined by model harmonization efforts conducted by the U.S. Department of Energy. Six sites in the U.S. southern-tier were sub-selected and assessed using daily site-specific algae biomass productivity data to determine the economic viability of large-scale open-pond systems. Results show that costs can vary significantly depending on location and biomass

  1. Assessment of Algal Farm Designs using a Dynamic Modular Approach

    SciTech Connect

    Abodeely, Jared M.; Stevens, Daniel M.; Ray, Allison E.; Newby, Deborah T.; Coleman, Andre M.; Cafferty, Kara G.

    2014-07-01

    The notion of renewable energy provides an importantmechanism for diversifying an energy portfolio,which ultimately would have numerous benefits including increased energy resilience, reduced reliance on foreign energysupplies, reduced GHG emissions, development of a green energy sector that contributes to economic growth,and providing a sustainable energy supply. The conversion of autotrophic algae to liquid transportation fuels is the basis of several decades of research to competitively bring energy-scale production into reality; however, many challenges still remain for making algal biofuels economically viable. Addressing current challenges associatedwith algal production systems, in part, requires the ability to assess spatial and temporal variability, rapidly evaluate alternative algal production system designs, and perform large-scale assessments considering multiple scenarios for thousands of potential sites. We introduce the development and application of the Algae Logistics Model (ALM) which is tailored to help address these challenges. The flexible nature of the ALM architecture allows the model to: 1) interface with external biomass production and resource assessment models, as well as other relevant datasets including those with spatiotemporal granularity; 2) interchange design processes to enable operational and economic assessments ofmultiple design configurations, including the integration of current and new innovative technologies; and 3) conduct trade-off analysis to help understand the site-specific techno-economic trade-offs and inform technology decisions. This study uses the ALM to investigate a baseline open-pond production system determined by model harmonization efforts conducted by the U.S. Department of Energy. Six sites in the U.S. southern-tierwere sub-selected and assessed using daily site-specific algaebiomass productivity data to determine the economic viability of large-scale open-pond systems. Results show that costs can vary

  2. Algal refossilization of atmospheric carbon dioxide. [Contains bibliography

    SciTech Connect

    Neushul, M. )

    1991-07-01

    The atmospheric concentration of carbon dioxide (CO{sub 2}) is steadily increasing. With our increasing awareness of the economic and environmental impacts of the greenhouse effects'' of CO{sub 2}, methane and other gases, there is interest in finding new methods to reduce the amounts of these gases in the atmosphere. This study evaluates the possibility that large-scale oceanic cultures of macroalgae (macroscopic seaweeds'') could be used to capture atmospheric CO{sub 2}. It is a design for a marine farm system in which a crop'' of calcareous macroalgae grows attached to, and supported by, floating macroalgae that comprise the farm structure.'' The least complicated, yet feasible, macroalgal farm system appears to be one in which laboratory-propagated calcareous algal epiphytes'' and floating algal basiphytes'' are dispersed together in natural ocean upwelling regions. From there, the plants drift with surface currents to the open ocean and then sink to the sea floor, where the buried carbon is refossilized.'' An important caveat regarding the use of calcareous algae is that the process of calcification may release CO{sub 2} to the atmosphere. There is some evidence that CO{sub 2} is not released by calcification in red calcareous algae, but in contrast many geochemists feel that all biologically -- as well as chemically --mediated calcification processes release CO{sub 2}. A substantial amount of research will be necessary to answer basic questions about algal carbon fixation and biomineralization on one hand, while on the other hand to devise strategies for farming the open ocean. 76 refs., 14 figs., 7 tabs.

  3. A trait-based framework for stream algal communities.

    PubMed

    Lange, Katharina; Townsend, Colin Richard; Matthaei, Christoph David

    2016-01-01

    The use of trait-based approaches to detect effects of land use and climate change on terrestrial plant and aquatic phytoplankton communities is increasing, but such a framework is still needed for benthic stream algae. Here we present a conceptual framework of morphological, physiological, behavioural and life-history traits relating to resource acquisition and resistance to disturbance. We tested this approach by assessing the relationships between multiple anthropogenic stressors and algal traits at 43 stream sites. Our "natural experiment" was conducted along gradients of agricultural land-use intensity (0-95% of the catchment in high-producing pasture) and hydrological alteration (0-92% streamflow reduction resulting from water abstraction for irrigation) as well as related physicochemical variables (total nitrogen concentration and deposited fine sediment). Strategic choice of study sites meant that agricultural intensity and hydrological alteration were uncorrelated. We studied the relationships of seven traits (with 23 trait categories) to our environmental predictor variables using general linear models and an information-theoretic model-selection approach. Life form, nitrogen fixation and spore formation were key traits that showed the strongest relationships with environmental stressors. Overall, FI (farming intensity) exerted stronger effects on algal communities than hydrological alteration. The large-bodied, non-attached, filamentous algae that dominated under high farming intensities have limited dispersal abilities but may cope with unfavourable conditions through the formation of spores. Antagonistic interactions between FI and flow reduction were observed for some trait variables, whereas no interactions occurred for nitrogen concentration and fine sediment. Our conceptual framework was well supported by tests of ten specific hypotheses predicting effects of resource supply and disturbance on algal traits. Our study also shows that investigating a

  4. A study of algal biomass potential in selected Canadian regions.

    SciTech Connect

    Passell, Howard David; Roach, Jesse Dillon; Klise, Geoffrey T.

    2011-11-01

    A dynamic assessment model has been developed for evaluating the potential algal biomass and extracted biocrude productivity and costs, using nutrient and water resources available from waste streams in four regions of Canada (western British Columbia, Alberta oil fields, southern Ontario, and Nova Scotia). The purpose of this model is to help identify optimal locations in Canada for algae cultivation and biofuel production. The model uses spatially referenced data across the four regions for nitrogen and phosphorous loads in municipal wastewaters, and CO{sub 2} in exhaust streams from a variety of large industrial sources. Other data inputs include land cover, and solar insolation. Model users can develop estimates of resource potential by manipulating model assumptions in a graphic user interface, and updated results are viewed in real time. Resource potential by location can be viewed in terms of biomass production potential, potential CO{sub 2} fixed, biocrude production potential, and area required. The cost of producing algal biomass can be estimated using an approximation of the distance to move CO{sub 2} and water to the desired land parcel and an estimation of capital and operating costs for a theoretical open pond facility. Preliminary results suggest that in most cases, the CO{sub 2} resource is plentiful compared to other necessary nutrients (especially nitrogen), and that siting and prospects for successful large-scale algae cultivation efforts in Canada will be driven by availability of those other nutrients and the efficiency with which they can be used and re-used. Cost curves based on optimal possible siting of an open pond system are shown. The cost of energy for maintaining optimal growth temperatures is not considered in this effort, and additional research in this area, which has not been well studied at these latitudes, will be important in refining the costs of algal biomass production. The model will be used by NRC-IMB Canada to identify

  5. A Collection of Algal Genomes from the JGI

    SciTech Connect

    Kuo, Alan; Grigoriev, Igor

    2012-03-19

    Algae, defined as photosynthetic eukaryotes other than plants, constitute a major component of fundamental eukaryotic diversity. Acquisition of the ability to conduct oxygenic photosynthesis through endosymbiotic events has been a principal driver of eukaryotic evolution, and today algae continue to underpin aquatic food chains as primary producers. Algae play profound roles in the carbon cycle, can impose health and economic costs through toxic blooms, and are candidate sources for bio-fuels; all of these research areas are part of the mission of DOE?s Joint Genome Institute (JGI). A collection of algal projects ongoing at JGI contributes to each of these areas and illustrates analyses employed in their genome exploration.

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

    SciTech Connect

    Rejean Samson; Anh LeDuy

    1982-08-01

    Spirulina maxima algal biomass could be used as the sole nutrient for the production of biogas by anaerobic digestion process. It is relatively simple to adapt the municipal sewage sludge to this new substrate. The adapted sludge is very stable. Under nonoptimal conditions, the methane yield and productivity obtained were 0.26 m/sup 3//(kg VS added day) and 0.26 m/sup 3//(kg VS added day), respectively, with the semicontinuous, daily fed, anaerobic digestion having loading rate of 0.97 kg VS/(m/sup 3/ day), retention time of 33 days and temperature of 30/sup 0/C.

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

    PubMed

    Kasai, F; Takamura, N; Hatakeyama, S

    1993-01-01

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

  8. Algal photoreceptors: in vivo functions and potential applications.

    PubMed

    Kianianmomeni, Arash; Hallmann, Armin

    2014-01-01

    Many algae, particularly microalgae, possess a sophisticated light-sensing system including photoreceptors and light-modulated signaling pathways to sense environmental information and secure the survival in a rapidly changing environment. Over the last couple of years, the multifaceted world of algal photobiology has enriched our understanding of the light absorption mechanisms and in vivo function of photoreceptors. Moreover, specific light-sensitive modules have already paved the way for the development of optogenetic tools to generate light switches for precise and spatial control of signaling pathways in individual cells and even in complex biological systems. PMID:24081482

  9. Beneficial Effects of Marine Algal Compounds in Cosmeceuticals

    PubMed Central

    Thomas, Noel Vinay; Kim, Se-Kwon

    2013-01-01

    The name “cosmeceuticals” is derived from “cosmetics and pharmaceuticals”, indicating that a specific product contains active ingredients. Marine algae have gained much importance in cosmeceutical product development due to their rich bioactive compounds. In the present review, marine algal compounds (phlorotannins, sulfated polysaccharides and tyrosinase inhibitors) have been discussed toward cosmeceutical application. In addition, atopic dermatitis and the possible role of matrix metalloproteinase (MMP) in skin-related diseases have been explored extensively for cosmeceutical products. The proper development of marine algae compounds will be helpful in cosmeceutical product development and in the development of the cosmeceutical industry. PMID:23344156

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

    PubMed

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

    1988-02-01

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

  11. Flexibility in Algal Endosymbioses Shapes Growth in Reef Corals

    NASA Astrophysics Data System (ADS)

    Little, Angela F.; van Oppen, Madeleine J. H.; Willis, Bette L.

    2004-06-01

    The relation between corals and their algal endosymbionts has been a key to the success of scleractinian (stony) corals as modern reef-builders, but little is known about early stages in the establishment of the symbiosis. Here, we show that initial uptake of zooxanthellae by juvenile corals during natural infection is nonspecific (a potentially adaptive trait); the association is flexible and characterized by a change in (dominant) zooxanthella strains over time; and growth rates of experimentally infected coral holobionts are partly contingent on the zooxanthella strain harbored, with clade C-infected juveniles growing two to three times as fast as those infected with clade D.

  12. Process Design and Economics for the Conversion of Algal Biomass to Biofuels: Algal Biomass Fractionation to Lipid- and Carbohydrate-Derived Fuel Products

    SciTech Connect

    Davis, R.; Kinchin, C.; Markham, J.; Tan, E.; Laurens, L.; Sexton, D.; Knorr, D.; Schoen, P.; Lukas, J.

    2014-09-01

    Beginning in 2013, NREL began transitioning from the singular focus on ethanol to a broad slate of products and conversion pathways, ultimately to establish similar benchmarking and targeting efforts. One of these pathways is the conversion of algal biomass to fuels via extraction of lipids (and potentially other components), termed the 'algal lipid upgrading' or ALU pathway. This report describes in detail one potential ALU approach based on a biochemical processing strategy to selectively recover and convert select algal biomass components to fuels, namely carbohydrates to ethanol and lipids to a renewable diesel blendstock (RDB) product. The overarching process design converts algal biomass delivered from upstream cultivation and dewatering (outside the present scope) to ethanol, RDB, and minor coproducts, using dilute-acid pretreatment, fermentation, lipid extraction, and hydrotreating.

  13. Algal culture studies related to a Closed Ecological Life Support System (CELSS)

    NASA Technical Reports Server (NTRS)

    Radmer, R. O.; Ollinger, O.; Venables, A.; Fernandez, E.

    1982-01-01

    Studies with algal cultures which relate to closed ecological life support systems (CELSS) are discussed. A description of a constant cell density apparatus for continuous culture of algae is included. Excretion of algal by-products, and nitrogen utilization and excretion are discussed.

  14. Releasing Stored Solar Energy within Pond Scum: Biodiesel from Algal Lipids

    ERIC Educational Resources Information Center

    Blatti, Jillian L.; Burkart, Michael D.

    2012-01-01

    Microalgae have emerged as an attractive feedstock for the mass production of renewable transportation fuels due to their fast growth rate, flexible habitat preferences, and substantial oil yields. As an educational tool, a laboratory was developed that mimics emerging algal biofuel technology, including the extraction of algal lipids and…

  15. Simplifying biodiesel production: the direct or 'in situ' transesterification of algal biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ‘in situ’ esterification/transesterification of algal biomass lipids to produce fatty acid methyl esters (FAME), for potential use as biodiesel, was investigated. Commercial algal biomass was employed, containing 20.9 wt percent hexane extractable oil. This consisted of 35.1 wt percent free fa...

  16. Will biodiesel derived from algal oils live up to its promise? A fuel property assessment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Algae have been attracting considerable attention as a source of biodiesel recently. This attention is largely due to the claimed high production potential of algal oils while circumventing the food vs. fuel issue. However, the properties of biodiesel fuels derived from algal oils have been only spa...

  17. ARS Research on Harmful Algal Blooms in SE USA Aquaculture Impoundments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As part of an EPA sponsored state of knowledge symposium on toxic cyanobacteria, six workgroups were established to assess published literature. A review of ARS research on harmful algal blooms was made by the incumbent. Aquaculture systems have had four types of freshwater toxic algal blooms. De...

  18. An algal removal using a combination of flocculation and flotation processes.

    PubMed

    Phoochinda, W; White, D A; Briscoe, B J

    2004-12-01

    The paper describes certain facets of the removal of the algae (Scenedesmus quadricauda) from water, using a froth flotation separation method, in conjunction with two types of surfactants, (cetyltrimethylammonium bromide) CTAB and (sodium dodecylsulfate) SDS. A 90% algal removal efficiency was achieved when 100 mg l(-1) of CTAB was used whereas for the SDS solutions, the same concentration gave, by comparison, a very poor algal removal efficiency. An addition of 1 mg l(-1) of a commercial cationic polyelectrolyte, which was the optimal concentration as was evident from the zeta potential and the particle size distribution measurements, prior to the SDS addition resulted in a formation of algal flocs and consequently a substantial improvement in the extent of the algal removal. A 50 mg l(-1) solution of SDS was found to be the optimal concentration to completely remove these algal flocs from water. The amount of water removed along with the algal flocs, produced using 1 mg l(-1) of the commercial polyelectrolyte and subsequently removed using SDS, was comparatively lower than that removed with the algal cells when CTAB was used as the 'collector'. It was generally found, in this study, that an addition of the polyelectrolyte improved the removal efficiencies and the rate of separation and also decreased the amount of the associated water removed along with the algal sludge. PMID:15691199

  19. Algicidal bacteria in the sea and their impact on algal blooms.

    PubMed

    Mayali, Xavier; Azam, Farooq

    2004-01-01

    Over the past two decades, many reports have revealed the existence of bacteria capable of killing phytoplankton. These algicidal bacteria sometimes increase in abundance concurrently with the decline of algal blooms, suggesting that they may affect algal bloom dynamics. Here, we synthesize the existing knowledge on algicidal bacteria interactions with marine eukaryotic microalgae. We discuss the effectiveness of the current methods to characterize the algicidal phenotype in an ecosystem context. We briefly consider the literature on the phylogenetic identification of algicidal bacteria, their interaction with their algal prey, the characterization of algicidal molecules, and the enumeration of algicidal bacteria during algal blooms. We conclude that, due to limitations of current methods, the evidence for algicidal bacteria causing algal bloom decline is circumstantial. New methods and an ecosystem approach are needed to test hypotheses on the impact of algicidal bacteria in algal bloom dynamics. This will require enlarging the scope of inquiry from its current focus on the potential utility of algicidal bacteria in the control of harmful algal blooms. We suggest conceptualizing bacterial algicidy within the general problem of bacterial regulation of algal community structure in the ocean. PMID:15134248

  20. Use of an algal hydrolysate to improve enzymatic hydrolysis of anaerobically digested fiber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated the use of acid hydrolyzed algae to enhance the enzymatic hydrolysis of cellulosic biomass. We first characterized wastewater-grown algal samples and determined the optimal conditions (acid concentration, reaction temperature, and reaction time) for algal hydrolysis using di...

  1. The effect of light direction and suspended cell concentrations on algal biofilm growth rates.

    PubMed

    Schnurr, Peter J; Espie, George S; Allen, D Grant

    2014-10-01

    Algae biofilms were grown in a semicontinuous flat plate biofilm photobioreactor to study the effects of light direction and suspended algal cell populations on algal biofilm growth. It was determined that, under the growth conditions and biofilm thicknesses studied, light direction had no effect on long-term algal biofilm growth (26 days); however, light direction did affect the concentration of suspended algal cells by influencing the photon flux density in the growth medium in the photobioreactors. This suspended algal cell population affected short-term (7 days) algae cell recruitment and algal biofilm growth, but additional studies showed that enhanced suspended algal cell populations did not affect biofilm growth rates over the long term (26 days). Studying profiles of light transmittance through biofilms as they grew showed that most of the light became attenuated by the biomass after just a few days of growth (88 % after 3 days). The estimated biofilm thicknesses after these few days of growth were approximately 150 μm. The light attenuation data suggests that, although the biofilms grew to 700-900 μm, under these light intensities, only the first few hundred micrometers of the biofilm is receiving enough light to be photosynthetically active. We postulate that this photosynthetically active layer of the biofilm grows adjacent to the light source, while the rest of the biofilm is in a stationary growth phase. The results of this study have implications for algal biofilm photobioreactor design and operation. PMID:25149444

  2. Measuring cellular-scale nutrient distribution in algal biofilms with synchrotron confocal infrared microspectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infrared microspectroscopy (IMS) and chemical imaging is ideal for measuring nutrient distribution in single algal cells on a cellular and subcellular level. The study of small algal cells, or cells within a colony requires enhanced spatial resolution IMS. Synchrotron infrared microspectroscopy wit...

  3. Alien Marine Fishes Deplete Algal Biomass in the Eastern Mediterranean

    PubMed Central

    Sala, Enric; Kizilkaya, Zafer; Yildirim, Derya; Ballesteros, Enric

    2011-01-01

    One of the most degraded states of the Mediterranean rocky infralittoral ecosystem is a barren composed solely of bare rock and patches of crustose coralline algae. Barrens are typically created by the grazing action of large sea urchin populations. In 2008 we observed extensive areas almost devoid of erect algae, where sea urchins were rare, on the Mediterranean coast of Turkey. To determine the origin of those urchin-less ‘barrens’, we conducted a fish exclusion experiment. We found that, in the absence of fish grazing, a well-developed algal assemblage grew within three months. Underwater fish censuses and observations suggest that two alien herbivorous fish from the Red Sea (Siganus luridus and S. rivulatus) are responsible for the creation and maintenance of these benthic communities with extremely low biomass. The shift from well-developed native algal assemblages to ‘barrens’ implies a dramatic decline in biogenic habitat complexity, biodiversity and biomass. A targeted Siganus fishery could help restore the macroalgal beds of the rocky infralittoral on the Turkish coast. PMID:21364943

  4. Tumebacillus algifaecis sp. nov., isolated from decomposing algal scum.

    PubMed

    Wu, Yu-Fan; Zhang, Bo; Xing, Peng; Wu, Qing-Long; Liu, Shuang-Jiang

    2015-07-01

    Bacterial strain THMBR28(T) was isolated from decomposing algal scum that was collected during an algal bloom in Taihu lake, China. Cells of strain THMBR28(T) were Gram-staining-positive, facultatively anaerobic and rod-shaped. Growth was observed at 20-45 °C (optimum, 30 °C), at pH 5.0-9.5 (optimum, pH 6.5-7.5), and in the presence of 0-1.0% (w/v) NaCl (optimum, 0.5%). Strain THMBR28(T) contained MK-7 as the major menaquinone and iso-C15 : 0 as the major cellular fatty acid. The polar lipid profile contained phosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine and six unidentified polar lipids. The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid. The DNA G+C content was 57.6 mol% (Tm). Phylogenetic analysis of 16S rRNA gene sequences showed that strain THMBR28(T) belonged to the genus Tumebacillus, most closely related to Tumebacillus ginsengisoli DSM 18389(T) (95.0%) and Tumebacillus permanentifrigoris Eur1 9.5(T) (93.4%). Based on phylogenetic and phenotypic characterization, it is concluded that strain THMBR28(T) represents a novel species of the genus Tumebacillus, for which the name Tumebacillus algifaecis sp. nov. is proposed, with THMBR28(T) ( = CGMCC 1.10949(T) = NBRC 108765(T)) as the type strain. PMID:25858243

  5. Raman spectroscopy for the characterization of algal cells

    NASA Astrophysics Data System (ADS)

    Samek, Ota; Jonáš, Alexandr; Pilát, Zdeněk; Zemánek, Pavel; Nedbal, Ladislav; Tříska, Jan; Kotas, Petr; Trtílek, Martin

    2010-12-01

    Raman spectroscopy can elucidate fundamental questions about intercellular variability and what governs it. Moreover, knowing the metabolic response on single cell level this can significantly contribute to the study and use of microalgae in systems biology and biofuel technology. Raman spectroscopy is capable to measure nutrient dynamics and metabolism in vivo, in real-time, label free making it possible to monitor/evaluate population variability. Also, degree of unsaturation of the algae oil (iodine value) can be measured using Raman spectra obtained from single microalgae. The iodine value is the determination of the amount of unsaturation contained in fatty acids (in the form of double bonds). Here we demonstrate the capacity of the spatially resolved Raman microspectroscopy to determine the effective iodine value in lipid storage bodies of individual living algal cells. We employed the characteristic peaks in the Raman scattering spectra at 1,656 cm-1 (cis C=C stretching mode) and 1,445 cm-1 (CH2 scissoring mode) as the markers defining the ratio of unsaturated-to-saturated carbon-carbon bonds of the fatty acids in the algal lipids.

  6. Dissolved organic matter reduces algal accumulation of methylmercury

    USGS Publications Warehouse

    Luengen, Allison C.; Fisher, Nicholas S.; Bergamaschi, Brian A.

    2012-01-01

    Dissolved organic matter (DOM) significantly decreased accumulation of methylmercury (MeHg) by the diatom Cyclotella meneghiniana in laboratory experiments. Live diatom cells accumulated two to four times more MeHg than dead cells, indicating that accumulation may be partially an energy-requiring process. Methylmercury enrichment in diatoms relative to ambient water was measured by a volume concentration factor (VCF). Without added DOM, the maximum VCF was 32 x 104, and the average VCF (from 10 to 72 h) over all experiments was 12.6 x 104. At very low (1.5 mg/L) added DOM, VCFs dropped by approximately half. At very high (20 mg/L) added DOM, VCFs dropped 10-fold. Presumably, MeHg was bound to a variety of reduced sulfur sites on the DOM, making it unavailable for uptake. Diatoms accumulated significantly more MeHg when exposed to transphilic DOM extracts than hydrophobic ones. However, algal lysate, a labile type of DOM created by resuspending a marine diatom in freshwater, behaved similarly to a refractory DOM isolate from San Francisco Bay. Addition of 67 μM L-cysteine resulted in the largest drop in VCFs, to 0.28 x 104. Although the DOM composition influenced the availability of MeHg to some extent, total DOM concentration was the most important factor in determining algal bioaccumulation of MeHg.

  7. Algal and microbial exopolysaccharides: new insights as biosurfactants and bioemulsifiers.

    PubMed

    Paniagua-Michel, José de Jesús; Olmos-Soto, Jorge; Morales-Guerrero, Eduardo Roberto

    2014-01-01

    Currently, efforts are being made to utilize more natural biological systems as alternatives as a way to replace fossil forms of carbon. There is a growing concern at global level to have nontoxic, nonhazardous surface-active agents; contrary to synthetic surfactants, their biological counterparts or biosurfactants play a primary function, facilitating microbial presence in environments dominated by hydrophilic-hydrophobic interfaces. Algal and microbial biosurfactants/bioemulsifiers from marine and deep-sea environments are attracting major interest due to their structural and functional diversity as molecules actives of surface and an alternative biomass to replace fossil forms of carbon. Algal and microbial surfactants are lipid in nature and classified as glycolipids, phospholipids, lipopeptides, natural lipids, fatty acids, and lipopolysaccharides. These metabolic bioactive products are applicable in a number of industries and processes, viz., food processing, pharmacology, and bioremediation of oil-polluted environments. This chapter presents an update of the progress and potentialities of the principal producers of exopolysaccharide (EPS)-type biosurfactants and bioemulsifiers, viz., macro- and microalgae (cyanobacteria and diatoms) and bacteria from marine and extreme environments. Particular interest is centered into new sources and applications, viz., marine and deep-sea environments and promissory uses of these EPSs as biosurfactants/emulsifiers and other polymeric roles. The enormous benefits of these molecules encourage their discovery, exploitation, and development of new microbial EPSs that could possess novel industrial importance and corresponding innovations. PMID:25300549

  8. Detection of toxic organometallic complexes in wastewaters using algal assays.

    PubMed

    Wong, S L; Nakamoto, L; Wainwright, J F

    1997-05-01

    Chlorella (a unicellular green alga) and Cladophora (a filamentous alga) were used in algal assays to identify the presence and toxicity of organometallic complexes in four industrial wastewaters. Toxicities of inorganic Pb and organometallic compounds (trimethyl, tetramethyl and tetraethyl leads, cacodylic acid and Cu-picolinate) were examined, using algal cells grown in 10% BBM solution. Inorganic Pb and organometallic compounds altered the fine structure of Chlorella cells in a distinguishable manner. X-ray microanalysis revealed that organometallic compounds accumulated in the neutral lipids of Cladophora cells. By applying the above techniques to the wastewater assays, two of the four wastewaters tested were found to contain organometallic complexes. Wastewater from a chemical company contained only traces of organo-Cu, but one mining effluent contained significant quantities of organo-Cu and organo-Pb, and traces of organo-Cr and organo-Tl (thallium). These studies suggest that X-ray microanalysis of algae may be a useful tool in identifying aquatic systems contaminated with metals and organometallic compounds. PMID:9175500

  9. Recycling produced water for algal cultivation for biofuels

    SciTech Connect

    Neal, Justin N.; Sullivan, Enid J.; Dean, Cynthia A.; Steichen, Seth A.

    2012-08-09

    Algal growth demands a continuous source of water of appropriate salinity and nutritional content. Fresh water sources are scarce in the deserts of the Southwestern United States, hence, salt water algae species are being investigated as a renewable biofuel source. The use of produced water from oil wells (PW) could offset the demand for fresh water in cultivation. Produced water can contain various concentrations of dissolved solids, metals and organic contaminants and often requires treatment beyond oil/water separation to make it suitable for algae cultivation. The produced water used in this study was taken from an oil well in Jal, New Mexico. An F/2-Si (minus silica) growth media commonly used to cultivate Nannochloropsis salina 1776 (NS 1776) was prepared using the produced water (F/2-Si PW) taking into account the metals and salts already present in the water. NS 1776 was seeded into a bioreactor containing 5L of the (F/2-Si PW) media. After eleven days the optical density at 750 nm (an indicator of algal growth) increased from 0 to 2.52. These results indicate algae are able to grow, though inhibited when compared with non-PW media, in the complex chemical conditions found in produced water. Savings from using nutrients present in the PW, such as P, K, and HCO{sub 3}{sup -}, results in a 44.38% cost savings over fresh water to mix the F/2-Si media.

  10. Didymosphenia geminata: Algal blooms in oligotrophic streams and rivers

    USGS Publications Warehouse

    Sundareshwar, P.V.; Upadhayay, S.; Abessa, M.; Honomichl, S.; Berdanier, B.; Spaulding, S.A.; Sandvik, C.; Trennepohl, A.

    2011-01-01

    In recent decades, the diatom Didymosphenia geminata has emerged as nuisance species in river systems around the world. This periphytic alga forms large "blooms" in temperate streams, presenting a counterintuitive result: the blooms occur primarily in oligotrophic streams and rivers, where phosphorus (P) availability typically limits primary production. The goal of this study is to examine how high algal biomass is formed under low P conditions. We reveal a biogeochemical process by which D. geminata mats concentrate P from flowing waters. First, the mucopolysaccaride stalks of D. geminata adsorb both iron (Fe) and P. Second, enzymatic and bacterial processes interact with Fe to increase the biological availability of P. We propose that a positive feedback between total stalk biomass and high growth rate is created, which results in abundant P for cell division. The affinity of stalks for Fe in association with iron-phosphorus biogeochemistry suggest a resolution to the paradox of algal blooms in oliogotrophic streams and rivers. Copyright 2011 by the American Geophysical Union.

  11. Four novel algal virus genomes discovered from Yellowstone Lake metagenomes

    PubMed Central

    Zhang, Weijia; Zhou, Jinglie; Liu, Taigang; Yu, Yongxin; Pan, Yingjie; Yan, Shuling; Wang, Yongjie

    2015-01-01

    Phycodnaviruses are algae-infecting large dsDNA viruses that are widely distributed in aquatic environments. Here, partial genomic sequences of four novel algal viruses were assembled from a Yellowstone Lake metagenomic data set. Genomic analyses revealed that three Yellowstone Lake phycodnaviruses (YSLPVs) had genome lengths of 178,262 bp, 171,045 bp, and 171,454 bp, respectively, and were phylogenetically closely related to prasinoviruses (Phycodnaviridae). The fourth (YSLGV), with a genome length of 73,689 bp, was related to group III in the extended family Mimiviridae comprising Organic Lake phycodnaviruses and Phaeocystis globosa virus 16 T (OLPG). A pair of inverted terminal repeats was detected in YSLPV1, suggesting that its genome is nearly complete. Interestingly, these four putative YSL giant viruses also bear some genetic similarities to Yellowstone Lake virophages (YSLVs). For example, they share nine non-redundant homologous genes, including ribonucleotide reductase small subunit (a gene conserved in nucleo-cytoplasmic large DNA viruses) and Organic Lake virophage OLV2 (conserved in the majority of YSLVs). Additionally, putative multidrug resistance genes (emrE) were found in YSLPV1 and YSLPV2 but not in other viruses. Phylogenetic trees of emrE grouped YSLPVs with algae, suggesting that horizontal gene transfer occurred between giant viruses and their potential algal hosts. PMID:26459929

  12. Marine mimivirus relatives are probably large algal viruses

    PubMed Central

    Monier, Adam; Larsen, Jens Borggaard; Sandaa, Ruth-Anne; Bratbak, Gunnar; Claverie, Jean-Michel; Ogata, Hiroyuki

    2008-01-01

    Background Acanthamoeba polyphaga mimivirus is the largest known ds-DNA virus and its 1.2 Mb-genome sequence has revealed many unique features. Mimivirus occupies an independent lineage among eukaryotic viruses and its known hosts include only species from the Acanthamoeba genus. The existence of mimivirus relatives was first suggested by the analysis of the Sargasso Sea metagenomic data. Results We now further demonstrate the presence of numerous "mimivirus-like" sequences using a larger marine metagenomic data set. We also show that the DNA polymerase sequences from three algal viruses (CeV01, PpV01, PoV01) infecting different marine algal species (Chrysochromulina ericina, Phaeocystis pouchetii, Pyramimonas orientalis) are very closely related to their homolog in mimivirus. Conclusion Our results suggest that the numerous mimivirus-related sequences identified in marine environments are likely to originate from diverse large DNA viruses infecting phytoplankton. Micro-algae thus constitute a new category of potential hosts in which to look for new species of Mimiviridae. PMID:18215256

  13. Evaluation of High Density Algal Cultivation for Secondary Wastewater Polishing.

    PubMed

    Xu, Meng; Xu, Shengnan; Bernards, Matthew; Hu, Zhiqiang

    2016-01-01

    This study evaluated the performance of an algal membrane bioreactor (A-MBR) for secondary wastewater effluent polishing and determined the membrane fouling behavior and dominance of algae in the A-MBR. The continuous flow A-MBR (effective volume = 7.2 L) was operated with low biomass wastage for more than 180 days, resulting in an average algal mixed liquor suspended solid concentration of 4922 mg/L. At the influent concentrations of 43 mg/L COD, 1.6 mg/L total phosphorus (TP), and 11.8 mg/L total nitrogen (TN), the effluent COD, TP and TN concentrations were 26 ± 6 mg/L, 0.7 ± 0.3 mg/L, and 9.6 ± 1.2 mg/L, respectively. High-density algae cultivation facilitated P adsorption and chemical precipitation. However, the TN removal efficiency was only 14% because of low biomass wastage. Although bacteria represented less than 2% of the total biomass in the A-MBR, bacterial growth in the secondary wastewater effluent accelerated membrane fouling. PMID:26803026

  14. Riparian shading controls instream spring phytoplankton and benthic algal growth.

    PubMed

    Halliday, S J; Skeffington, R A; Wade, A J; Bowes, M J; Read, D S; Jarvie, H P; Loewenthal, M

    2016-06-15

    Dissolved oxygen (DO) concentrations showed a striking pattern in a multi-year study of the River Enborne, a small river in SE England. In each of three years (2010-2012), maximum DO concentrations were attained in mid-April, preceded by a period of steadily increasing diurnal amplitudes, followed by a steady reduction in both amplitude and concentration. Flow events during the reduction period reduce DO to low concentrations until the following spring. Evidence is presented that this pattern is mainly due to benthic algal growth which is eventually suppressed by the growth of the riparian tree canopy. Nitrate and silicate concentrations are too high to inhibit the growth of either benthic algae or phytoplankton, but phosphate concentrations might have started to reduce growth if the tree canopy development had been delayed. This interpretation is supported by evidence from weekly flow cytometry measurements and analysis of the diurnal, seasonal and annual patterns of nutrient concentrations. As the tree canopy develops, the river switches from an autotrophic to a heterotrophic state. The results support the use of riparian shading to help control algal growth, and highlight the risks of reducing riparian shade. PMID:27192431

  15. Four novel algal virus genomes discovered from Yellowstone Lake metagenomes.

    PubMed

    Zhang, Weijia; Zhou, Jinglie; Liu, Taigang; Yu, Yongxin; Pan, Yingjie; Yan, Shuling; Wang, Yongjie

    2015-01-01

    Phycodnaviruses are algae-infecting large dsDNA viruses that are widely distributed in aquatic environments. Here, partial genomic sequences of four novel algal viruses were assembled from a Yellowstone Lake metagenomic data set. Genomic analyses revealed that three Yellowstone Lake phycodnaviruses (YSLPVs) had genome lengths of 178,262 bp, 171,045 bp, and 171,454 bp, respectively, and were phylogenetically closely related to prasinoviruses (Phycodnaviridae). The fourth (YSLGV), with a genome length of 73,689 bp, was related to group III in the extended family Mimiviridae comprising Organic Lake phycodnaviruses and Phaeocystis globosa virus 16 T (OLPG). A pair of inverted terminal repeats was detected in YSLPV1, suggesting that its genome is nearly complete. Interestingly, these four putative YSL giant viruses also bear some genetic similarities to Yellowstone Lake virophages (YSLVs). For example, they share nine non-redundant homologous genes, including ribonucleotide reductase small subunit (a gene conserved in nucleo-cytoplasmic large DNA viruses) and Organic Lake virophage OLV2 (conserved in the majority of YSLVs). Additionally, putative multidrug resistance genes (emrE) were found in YSLPV1 and YSLPV2 but not in other viruses. Phylogenetic trees of emrE grouped YSLPVs with algae, suggesting that horizontal gene transfer occurred between giant viruses and their potential algal hosts. PMID:26459929

  16. Flocculation of algal cells by amphoteric chitosan-based flocculant.

    PubMed

    Dong, Changlong; Chen, Wei; Liu, Cheng

    2014-10-01

    A kind of amphoteric chitosan-based flocculant (quaternized carboxymethyl chitosan, denoted as QCMC) has been prepared. QCMC presented significant improvement of water solubility in the whole pH range. The effects of pH, dosage, temperature and original turbidity of algal water on the flocculation performance were investigated. The optimal dosages of QCMC at pH 5, 9 and 12 with original turbidity of 20NTU at 20°C were 0.1, 0.6 and 2.0mg/L, respectively, which were much less than that of chitosan, PAM, Al2(SO4)3 and FeCl3. The floc properties during grow, breakage and regrow period were also evaluated at different pH values in terms of floc size, strength and density. It was demonstrated that QCMC produced larger, stronger and denser flocs than Al2(SO4)3. There is every indication that QCMC is more suitable for algal harvesting than other traditional coagulants or flocculants. PMID:25146316

  17. The laboratory mouse in routine food safety testing for marine algal biotoxins and harmful algal bloom toxin research: past, present and future.

    PubMed

    Stewart, Ian; McLeod, Catherine

    2014-01-01

    Mouse bioassays have been a mainstay for detecting harmful concentrations of marine algal toxins in shellfish for over 70 years. Routine monitoring involves intraperitoneal injection of shellfish extracts into mice; shellfish contaminated with algal toxins are thus identified by mortality in exposed mice. With the advent of alternative test methods to detect and quantify specific algal toxins has come increasing criticism of enduring use of mouse bioassays for shellfish safety testing. However, the complete replacement of shellfish safety mouse bioassays by chemical, antibody-based, and functional assays has been and will continue to be a gradual process for various reasons, including skills availability and instrument costs for chromatography-based toxin monitoring. Mouse bioassays for shellfish safety testing do not comply with modern standards for laboratory animal welfare, specifically the requirement in published official methods for death as a test outcome. Mouse bioassays for algal biotoxins in shellfish, as well as fundamental algal toxin research endeavors using in vivo models, are amenable to revision and refinement from a humane endpoints perspective. Regulated hypothermia may be a useful and easily acquired nonlethal toxicological endpoint; objective determination of neuromuscular blockade may allow algal neurotoxin testing and research to enter the domain of humane endpoints evaluation. Relinquishing reliance on subjective test endpoints, including death, will likely also deliver collateral improvements in assay variability and sensitivity. PMID:24830147

  18. Effects of electron acceptors on soluble reactive phosphorus in the overlying water during algal decomposition.

    PubMed

    Wang, Jinzhi; Jiang, Xia; Zheng, Binghui; Niu, Yuan; Wang, Kun; Wang, Wenwen; Kardol, Paul

    2015-12-01

    Endogenous phosphorus (P) release from sediments is an important factor to cause eutrophication and, hence, algal bloom in lakes in China. Algal decomposition depletes dissolved oxygen (DO) and causes anaerobic conditions and therefore increases P release from sediments. As sediment P release is dependent on the iron (Fe) cycle, electron acceptors (e.g., NO3 (-), SO4 (2-), and Mn(4+)) can be utilized to suppress the reduction of Fe(3+) under anaerobic conditions and, as such, have the potential to impair the release of sediment P. Here, we used a laboratory experiment to test the effects of FeCl3, MnO2, and KNO3 on soluble reactive phosphorus (SRP) concentration and related chemical variables in the overlying water column during algal decomposition at different algal densities. Results showed that algal decomposition significantly depleted DO and thereby increased sediment Fe-bound P release. Compared with the control, addition of FeCl3 significantly decreased water SRP concentration through inhibiting sediment P release. Compared with FeCl3, addition of MnO2 has less potential to suppress sediment P release during algal decomposition. Algal decomposition has the potential for NO3 (-) removal from aquatic ecosystem through denitrification and by that alleviates the suppressing role of NO3 (-) on sediment P release. Our results indicated that FeCl3 and MnO2 could be efficient in reducing sediment P release during algal decomposition, with the strongest effect found for FeCl3; large amounts of NO3 (-) were removed from the aquatic ecosystem through denitrification during algal decomposition. Moreover, the amounts of NO3 (-) removal increased with increasing algal density. PMID:26263882

  19. How hydrodynamics control algal blooms in the Ythan estuary, Scotland

    NASA Astrophysics Data System (ADS)

    Champangern, Khruewan; Hoey, Trevor; Thomas, Rhian

    2016-04-01

    The Ythan estuary, northeast Scotland, was designated in 2000 as a Nitrate Vulnerable Zone (NVZ) under the European Commission (EC) Nitrates Directive. Much of the catchment is intensively farmed and water quality has been adversely affected by nutrients from agricultural fertilizers. As a result, algal mats develop annually on tidal flats where sediment from upstream and from the adjacent dune systems is deposited. Understanding the patterns of water (river and ocean) circulation in the estuary as well as understanding how nutrients and sediments are transported in the estuary is crucial for understanding the role of several factors (elevation; sediment characteristics; nutrient flux) control the locations and scale of annual algal blooms. In order to understand those controls, study of interactions between hydrodynamic factors and water quality, in particular chlorophyll levels, at different time scales has been carried out. The results from the study reveal complex seasonal and event-scale relationships of river flow with the amount of chlorophyll, which provide an initial comprehension of controls over the concentrations of chlorophyll in the estuary. The concentration of chlorophyll changes, whether increasing or decreasing, with regards to changes in river flow. During high flow events, high amounts of chlorophyll are found when the tide is low. During low flow events, high amounts of chlorophyll are found at high tides. These phenomena reveal that both river flow and tidal cycle affect the amount of chlorophyll in the estuary. In addition, the Delft3d flow model, which has been extensively applied to many coastal and estuarine studies is used to simulate hydrodynamic patterns in the estuary during high flow and low flow events. The model is composed of 36,450 fine resolution grids and the upstream/ downstream boundary that represents water level is based on time-series data from river flow and tidal measurements. The bathymetry used for the model domain is

  20. In-vivo absorption properties of algal pigments

    NASA Astrophysics Data System (ADS)

    Bidigare, Robert R.; Ondrusek, Michael E.; Morrow, John H.; Kiefer, Dale A.

    1990-09-01

    Estimates of the in vivo specific absorption coefficients (m2 mg'; 400-750 nm, 2 nm intervals) for the major algal pigment groups (chlorophylls, carotenoids and phycobilins) are presented. "Unpackaged" absorption coefficients were initially obtained by measuring the absorption properties of pure pigment standards spectrophotometrically and "shifting" their absorption maxima to match in vivo positions. Two approaches for estimating the phytoplankton absorption coefficient (spectral reconstruction and spectral decomposition) are compared by linear regression analysis, incorporating concurrent measurements of particulate absorption and pigmentation performed in the Sargasso Sea. Results suggest that "pigment package" effects are minimal for natural assemblages of open-oceanic phytoplankton and that accessory pigments do not always co-vary with chlorophyll a over depth and time.

  1. Excitation Energy-Transfer Dynamics of Brown Algal Photosynthetic Antennas.

    PubMed

    Kosumi, D; Kita, M; Fujii, R; Sugisaki, M; Oka, N; Takaesu, Y; Taira, T; Iha, M; Hashimoto, H

    2012-09-20

    Fucoxanthin-chlorophyll-a/c protein (FCP) complexes from brown algae Cladosiphon okamuranus TOKIDA (Okinawa Mozuku in Japanese) contain the only species of carbonyl carotenoid, fucoxanthin, which exhibits spectral characteristics attributed to an intramolecular charge-transfer (ICT) property that arises in polar environments due to the presence of the carbonyl group in its polyene backbone. Here, we investigated the role of the ICT property of fucoxanthin in ultrafast energy transfer to chlorophyll-a/c in brown algal photosynthesis using femtosecond pump-probe spectroscopic measurements. The observed excited-state dynamics show that the ICT character of fucoxanthin in FCP extends its absorption band to longer wavelengths and enhances its electronic interaction with chlorophyll-a molecules, leading to efficient energy transfer from fucoxanthin to chlorophyll-a. PMID:26295888

  2. Energy-efficient photobioreactor configuration for algal biomass production.

    PubMed

    Pegallapati, Ambica Koushik; Arudchelvam, Yalini; Nirmalakhandan, Nagamany

    2012-12-01

    An internally illuminated photobioreactor (IIPBR) design is proposed for energy-efficient biomass production. Theoretical rationale of the IIPBR design and its advantages over the traditional bubble column photobioreactors (PBRs) are presented, followed by experimental results from prototype scale cultivation of freshwater and marine algal strains in an 18L IIPBR. Based on theoretical considerations, the proposed IIPBR design has the potential to support 160% higher biomass density and higher biomass productivity per unit energy input, B/E, than a bubble column PBR of equal incident area per unit culture volume. Experimental B/E values recorded in this study with fresh water algae and marine algae (1.42 and 0.37 gW(-1)d(-1), respectively) are at least twice as those reported in the literature for comparable species cultivated in bubble column and airlift PBRs. PMID:23079413

  3. Algal-based, single-step treatment of urban wastewaters.

    PubMed

    Henkanatte-Gedera, S M; Selvaratnam, T; Caskan, N; Nirmalakhandan, N; Van Voorhies, W; Lammers, Peter J

    2015-08-01

    Currently, urban wastewaters (UWW) laden with organic carbon (BOD) and nutrients (ammoniacal nitrogen, N, and phosphates, P) are treated in multi-stage, energy-intensive process trains to meet the mandated discharge standards. This study presents a single-step process based on mixotrophic metabolism for simultaneous removal of carbon and nutrients from UWWs. The proposed system is designed specifically for hot, arid environments utilizing an acidophilic, thermotolerant algal species, Galdieria sulphuraria, and an enclosed photobioreactor to limit evaporation. Removal rates of BOD, N, and P recorded in this study (14.93, 7.23, and 1.38 mg L(-1) d(-1), respectively) are comparable to literature reports. These results confirm that the mixotrophic system can reduce the energy costs associated with oxygen supply in current UWW treatment systems, and has the potential to generate more energy-rich biomass for net energy extraction from UWW. PMID:25898089

  4. Freshwater harmful algal blooms: toxins and children's health.

    PubMed

    Weirich, Chelsea A; Miller, Todd R

    2014-01-01

    Massive accumulations of cyanobacteria (a.k.a. "blue-green algae"), known as freshwater harmful algal blooms (FHABs), are a common global occurrence in water bodies used for recreational purposes and drinking water purification. Bloom prevalence is increased due to anthropogenic changes in land use, agricultural activity, and climate change. These photosynthetic bacteria produce a range of toxic secondary metabolites that affect animals and humans at both chronic and acute dosages. Children are especially at risk because of their lower body weight, behavior, and toxic effects on development. Here we review common FHAB toxins, related clinical symptoms, acceptable concentrations in drinking water, case studies of children's and young adults' exposures to FHAB toxins through drinking water and food, methods of environmental and clinical detection in potential cases of intoxication, and best practices for FHAB prevention. PMID:24439026

  5. Arrest of cytoplasmic streaming induces algal proliferation in green paramecia.

    PubMed

    Takahashi, Toshiyuki; Shirai, Yohji; Kosaka, Toshikazu; Hosoya, Hiroshi

    2007-01-01

    A green ciliate Paramecium bursaria, bearing several hundreds of endosymbiotic algae, demonstrates rotational microtubule-based cytoplasmic streaming, in which cytoplasmic granules and endosymbiotic algae flow in a constant direction. However, its physiological significance is still unknown. We investigated physiological roles of cytoplasmic streaming in P. bursaria through host cell cycle using video-microscopy. Here, we found that cytoplasmic streaming was arrested in dividing green paramecia and the endosymbiotic algae proliferated only during the arrest of cytoplasmic streaming. Interestingly, arrest of cytoplasmic streaming with pressure or a microtubule drug also induced proliferation of endosymbiotic algae independently of host cell cycle. Thus, cytoplasmic streaming may control the algal proliferation in P. bursaria. Furthermore, confocal microscopic observation revealed that a division septum was formed in the constricted area of a dividing paramecium, producing arrest of cytoplasmic streaming. This is a first report to suggest that cytoplasmic streaming controls proliferation of eukaryotic cells. PMID:18159235

  6. Algal Growth Potential of Microcystis aeruginosa from Reclaimed Water.

    PubMed

    Joo, Jin Chul; Ahn, Chang Hyuk; Lee, Saeromi; Jang, Dae-Gyu; Lee, Woo Hyoung; Ryu, Byong Ro

    2016-01-01

    Algal growth potential (AGP) of the cyanobacterium Microcystis aeruginosa (M. aeruginosa, NIES-298) using reclaimed water from various wastewater reclamation pilot plants was investigated to evaluate the feasibility of the reclaimed water usage for recreational purposes. After completing the coagulation and ultrafiltration processes, the concentrations of most contaminants in the reclaimed water were lower than the reuse guidelines for recreational water. However, M. aeruginosa successfully adapted to low levels of soluble reactive phosphorus (PO(3-)(4)) concentrations. The AGP values of M. aeruginosa decreased with the progression of treatment processes, and with the increases in the dilution volume. Also, both the AGP and chlorophyll-a values can be estimated a priori without conducting the AGP tests. Therefore, aquatic ecosystems in locations prone to environmental conditions favorable for the growth of M. aeruginosa require more rigorous nutrient management plans (e.g., reverse osmosis and dilution with clean water resources) to reduce the nutrient availability. PMID:26803027

  7. Separation of algal cells from water by column flotation

    SciTech Connect

    Liu, J.C.; Chen, Y.M.; Ju, Y.H.

    1999-08-01

    The dispersed air flotation (DiAF) process was utilized to separate algal cells (Chlorella sp.) from water. Two types of collector, cationic N-cetyl-N,N,N-trimethylammonium bromide (CTAB) and anionic sodium dodecylsulfate (SDS), were used. It was observed that 20% of cell removal was achieved in the presence of 40 mg/L of SDS, and ca. 86% of the cells were removed at 40 mg/L of CTAB. Upon the addition of 10 mg/L of chitosan, over 90% of the cells were removed when SDS (20 mg/L) was used as the collector. Air flow rate affected cell flotation slightly. Optimum pH values for cell flotation were from 4.0 to 5.0. Flotation efficiency decreased at high ionic strength. The electrostatic interaction between collector and cell surface plays a critical role in the separation processes.

  8. Development of a simple means for predicting algal blooms

    SciTech Connect

    Litten, S.; Effler, S.W.; Meyer, M.

    1980-09-01

    A simple technique to predict the future occurrence of algal blooms was evaluated for seven test lake systems proximate to Syracuse, NY during the summer of 1978 and 1979. The selected test systems represent a broad range of trophic status, from mesotrophic to hypereutrophic. The technique includes a simple filtering process followed by the identification of the color imparted to the filter, based on comparison to National Bureau of Standards' color chips. The reference measure of phytoplankton standing crop was chlorophyll-a. Particular colors of filtered particulates were not demonstrated to be useful estimators of chlorophyll-a concentration, though the hues olive and yellow-green were associated with higher chlorophyll-a levels. The particulate color method was demonstrated to be useful in following certain physical/chemical changes in a lake.

  9. Evidence for water-mediated mechanisms in coral-algal interactions.

    PubMed

    Jorissen, Hendrikje; Skinner, Christina; Osinga, Ronald; de Beer, Dirk; Nugues, Maggy M

    2016-08-17

    Although many coral reefs have shifted from coral-to-algal dominance, the consequence of such a transition for coral-algal interactions and their underlying mechanisms remain poorly understood. At the microscale, it is unclear how diffusive boundary layers (DBLs) and surface oxygen concentrations at the coral-algal interface vary with algal competitors and competitiveness. Using field observations and microsensor measurements in a flow chamber, we show that coral (massive Porites) interfaces with thick turf algae, macroalgae, and cyanobacteria, which are successful competitors against coral in the field, are characterized by a thick DBL and hypoxia at night. In contrast, coral interfaces with crustose coralline algae, conspecifics, and thin turf algae, which are poorer competitors, have a thin DBL and low hypoxia at night. Furthermore, DBL thickness and hypoxia at the interface with turf decreased with increasing flow speed, but not when thick turf was upstream. Our results support the importance of water-mediated transport mechanisms in coral-algal interactions. Shifts towards algal dominance, particularly dense assemblages, may lead to thicker DBLs, higher hypoxia, and higher concentrations of harmful metabolites and pathogens along coral borders, which in turn may facilitate algal overgrowth of live corals. These effects may be mediated by flow speed and orientation. PMID:27512146

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

    PubMed

    Benes, Kylla M; Carpenter, Robert C

    2015-01-01

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

  11. [Study on the variation of algal activity during the electrochemical oxidation as inactivation method].

    PubMed

    Liang, Wen-Yan; Wang, Ke; Ruan, Ling-Ling; Sui, Li-Li

    2010-06-01

    The paper studied the variation of algal activity during the electrochemical inactivation and the influence factors by the use of TTC-dehydrogenase activity and neutral red staining assays. The treatment reactor was consisted of Ti/RuO2 rod as anode and stainless steel pipe as cathode. The results showed that algal inactivation rate was 45% in cell density after 30 min treatment at 8 mA/cm2. Whereas the decrease of TTC-dehydrogenase activity was 94% and neutral red staining percentage was 100%. The algae after treatment was unable to regrow and it revealed that the algal activity assays can reflect the inactivation effect more correctly than cell density. The electrolytes could influence the inactivation efficiency. The electrolytes of Na2SO4 and NaNO3 had similar effects on algal inactivation and Na2SO4 concentration had small influence on the treatment. However, when the electrolyte contained 0.1 mmol/L NaCl, the algal inactivation was improved obviously with the 87% for TTC-dehydrogenase activity decrease and 82% for neutral red staining ratio. The initial algal concentration also influenced the treatment efficiency. If cell density increased, the inactivation efficiency decreased significantly. All algal cells in samples with cell density of 4.4 x 10(7) cells/L were completely inactivated by the use of natural water as electrolyte within 1 minute. PMID:20698257

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

    SciTech Connect

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

    1984-10-01

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

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

    PubMed Central

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

    2016-01-01

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

  14. Algal Pretreatment Improves Biofuels Yield and Value; Highlights in Science, NREL (National Renewable Energy Laboratory)

    SciTech Connect

    2015-05-15

    One of the major challenges associated with algal biofuels production in a biorefinery-type setting is improving biomass utilization in its entirety, increasing the process energetic yields and providing economically viable and scalable co-product concepts. We demonstrate the effectiveness of a novel, integrated technology based on moderate temperatures and low pH to convert the carbohydrates in wet algal biomass to soluble sugars for fermentation, while making lipids more accessible for downstream extraction and leaving a protein-enriched fraction behind. This research has been highlighted in the Green Chemistry journal article mentioned above and a milestone report, and is based on the work the researchers are doing for the AOP projects Algal Biomass Conversion and Algal Biofuels Techno-economic Analysis. That work has demonstrated an advanced process for algal biofuel production that captures the value of both the algal lipids and carbohydrates for conversion to biofuels.  With this process, as much as 150 GGE/ton of biomass can be produced, 2-3X more than can be produced by terrestrial feedstocks.  This can also reduce the cost of biofuel production by as much as 40%. This also represents the first ever design case for the algal lipid upgrading pathway.

  15. Critical evaluation and modeling of algal harvesting using dissolved air flotation.

    PubMed

    Zhang, Xuezhi; Hewson, John C; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2014-12-01

    In this study, Chlorella zofingiensis harvesting by dissolved air flotation (DAF) was critically evaluated with regard to algal concentration, culture conditions, type and dosage of coagulants, and recycle ratio. Harvesting efficiency increased with coagulant dosage and leveled off at 81%, 86%, 91%, and 87% when chitosan, Al(3+) , Fe(3+) , and cetyl trimethylammonium bromide (CTAB) were used at dosages of 70, 180, 250, and 500 mg g(-1) , respectively. The DAF efficiency-coagulant dosage relationship changed with algal culture conditions. Evaluation of the influence of the initial algal concentration and recycle ratio revealed that, under conditions typical for algal harvesting, it is possible that the number of bubbles is insufficient. A DAF algal harvesting model was developed to explain this observation by introducing mass-based floc size distributions and a bubble limitation into the white water blanket model. The model revealed the importance of coagulation to increase floc-bubble collision and attachment, and the preferential interaction of bubbles with larger flocs, which limited the availability of bubbles to the smaller sized flocs. The harvesting efficiencies predicted by the model agree reasonably with experimental data obtained at different Al(3+) dosages, algal concentrations, and recycle ratios. Based on this modeling, critical parameters for efficient algal harvesting were identified. PMID:24889919

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

    PubMed

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Engelsen, Anna; Pihl, Leif

    2008-08-01

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

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

    NASA Astrophysics Data System (ADS)

    Raffaelli, D.

    2000-07-01

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

  19. In Situ Oxygen Dynamics in Coral-Algal Interactions

    PubMed Central

    Wangpraseurt, Daniel; Weber, Miriam; Røy, Hans; Polerecky, Lubos; de Beer, Dirk; Suharsono; Nugues, Maggy M.

    2012-01-01

    Background Coral reefs degrade globally at an alarming rate, with benthic algae often replacing corals. However, the extent to which benthic algae contribute to coral mortality, and the potential mechanisms involved, remain disputed. Recent laboratory studies suggested that algae kill corals by inducing hypoxia on the coral surface, through stimulated microbial respiration. Methods/Findings We examined the main premise of this hypothesis by measuring in situ oxygen microenvironments at the contact interface between the massive coral Porites spp. and turf algae, and between Porites spp. and crustose coralline algae (CCA). Oxygen levels at the interface were similar to healthy coral tissue and ranged between 300–400 µM during the day. At night, the interface was hypoxic (∼70 µM) in coral-turf interactions and close to anoxic (∼2 µM) in coral-CCA interactions, but these values were not significantly different from healthy tissue. The diffusive boundary layer (DBL) was about three times thicker at the interface than above healthy tissue, due to a depression in the local topography. A numerical model, developed to analyze the oxygen profiles above the irregular interface, revealed strongly reduced net photosynthesis and dark respiration rates at the coral-algal interface compared to unaffected tissue during the day and at night, respectively. Conclusions/Significance Our results showed that hypoxia was not a consistent feature in the microenvironment of the coral-algal interface under in situ conditions. Therefore, hypoxia alone is unlikely to be the cause of coral mortality. Due to the modified topography, the interaction zone is distinguished by a thicker diffusive boundary layer, which limits the local metabolic activity and likely promotes accumulation of potentially harmful metabolic products (e.g., allelochemicals and protons). Our study highlights the importance of mass transfer phenomena and the need for direct in situ measurements of microenvironmental

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

    PubMed

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

    2008-04-01

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

  1. Do coralline red algal growth increment widths archive paleoenvironmental information?

    NASA Astrophysics Data System (ADS)

    Halfar, J.; Winsborough, C.; Omar, A.; Hetzinger, S.; Steneck, R. S.; Lebednik, P. A.

    2009-04-01

    Over the past decade coralline red algae have received increased attention as archives of paleoclimate information. Encrusting coralline red algae, which deposit annual growth increments in a High-Mg calcite skeleton, are amongst the longest-lived marine organisms. In fact, a live-collected plant has recently been shown to have lived for at least 850 years based on radiometric dating. While a number of investigations have successfully utilized geochemical information obtained from coralline red algal skeletons to reconstruct climate, no study has yet examined the potential of using growth increment widths as a proxy for past water temperatures. Here we explore the relationship between growth and environmental parameters in Clathromorphum nereostratum from the Bering Sea. A 120-year long annual growth record shows a significant but weak correlation to regional sea surface temperature data (r=0.24), which requires much of the observed annual growth increment width variability to be explained by other factors. We therefore examined coralline red algal growth for a 20-year period in multiple specimens collected along a depth transect from 10 to 35 m water depth. Results demonstrate a significant decrease in average annual growth increment widths with increasing water depth. Due to intense wind-induced mixing in the region the upper water column exhibits near uniform temperatures and salinities, leaving the decreasing amount of light with depth as the dominant variable influencing vertical extension. This was further tested by examining specimens collected at 10 m water depth at different locations receiving distinct amounts of shading provided by 100%, 50%, and 0% kelp canopy coverage. Results indicate a negative relationship between percent kelp canopy coverage and annual growth increment width. It can therefore be concluded that the dominant factor controlling vertical growth in C. nereostratum is light, with temperature only accounting for a small portion of growth

  2. Hyperspectral and Physiological Analyses of Coral-Algal Interactions

    PubMed Central

    Barott, Katie; Smith, Jennifer; Dinsdale, Elizabeth; Hatay, Mark; Sandin, Stuart; Rohwer, Forest

    2009-01-01

    Space limitation leads to competition between benthic, sessile organisms on coral reefs. As a primary example, reef-building corals are in direct contact with each other and many different species and functional groups of algae. Here we characterize interactions between three coral genera and three algal functional groups using a combination of hyperspectral imaging and oxygen microprofiling. We also performed in situ interaction transects to quantify the relative occurrence of these interaction on coral reefs. These studies were conducted in the Southern Line Islands, home to some of the most remote and near-pristine reefs in the world. Our goal was to determine if different types of coral-coral and coral-algal interactions were characterized by unique fine-scale physiological signatures. This is the first report using hyperspectral imaging for characterization of marine benthic organisms at the micron scale and proved to be a valuable tool for discriminating among different photosynthetic organisms. Consistent patterns emerged in physiology across different types of competitive interactions. In cases where corals were in direct contact with turf or macroalgae, there was a zone of hypoxia and altered pigmentation on the coral. In contrast, interaction zones between corals and crustose coralline algae (CCA) were not hypoxic and the coral tissue was consistent across the colony. Our results suggest that at least two main characteristic coral interaction phenotypes exist: 1) hypoxia and coral tissue disruption, seen with interactions between corals and fleshy turf and/or some species of macroalgae, and 2) no hypoxia or tissue disruption, seen with interactions between corals and some species of CCA. Hyperspectral imaging in combination with oxygen profiling provided useful information on competitive interactions between benthic reef organisms, and demonstrated that some turf and fleshy macroalgae can be a constant source of stress for corals, while CCA are not. PMID

  3. Plant and algal cell walls: diversity and functionality

    PubMed Central

    Popper, Zoë A.; Ralet, Marie-Christine; Domozych, David S.

    2014-01-01

    Background Although plants and many algae (e.g. the Phaeophyceae, brown, and Rhodophyceae, red) are only very distantly related they are united in their possession of carbohydrate-rich cell walls, which are of integral importance being involved in many physiological processes. Furthermore, wall components have applications within food, fuel, pharmaceuticals, fibres (e.g. for textiles and paper) and building materials and have long been an active topic of research. As shown in the 27 papers in this Special Issue, as the major deposit of photosynthetically fixed carbon, and therefore energy investment, cell walls are of undisputed importance to the organisms that possess them, the photosynthetic eukaryotes (plants and algae). The complexities of cell wall components along with their interactions with the biotic and abiotic environment are becoming increasingly revealed. Scope The importance of plant and algal cell walls and their individual components to the function and survival of the organism, and for a number of industrial applications, are illustrated by the breadth of topics covered in this issue, which includes papers concentrating on various plants and algae, developmental stages, organs, cell wall components, and techniques. Although we acknowledge that there are many alternative ways in which the papers could be categorized (and many would fit within several topics), we have organized them as follows: (1) cell wall biosynthesis and remodelling, (2) cell wall diversity, and (3) application of new technologies to cell walls. Finally, we will consider future directions within plant cell wall research. Expansion of the industrial uses of cell walls and potentially novel uses of cell wall components are both avenues likely to direct future research activities. Fundamentally, it is the continued progression from characterization (structure, metabolism, properties and localization) of individual cell wall components through to defining their roles in almost every

  4. Distribution of heavy metals from flue gas in algal bioreactor

    NASA Astrophysics Data System (ADS)

    Napan, Katerine

    Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavy metals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavy metals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavy metals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavy metals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavy metal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavy metal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavy metals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavy metals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

  5. Pyrolysis Strategies for Effective Utilization of Lignocellulosic and Algal Biomass

    NASA Astrophysics Data System (ADS)

    Maddi, Balakrishna

    Pyrolysis is a processing technique involving thermal degradation of biomass in the absence of oxygen. The bio-oils obtained following the condensation of the pyrolysis vapors form a convenient starting point for valorizing the major components of lignocellulosic as well as algal biomass feed stocks for the production of fuels and value-added chemicals. Pyrolysis can be implemented on whole biomass or on residues left behind following standard fractionation methods. Microalgae and oil seeds predominantly consist of protein, carbohydrate and triglycerides, whereas lignocellulose is composed of carbohydrates (cellulose and hemicellulose) and lignin. The differences in the major components of these two types of biomass will necessitate different pyrolysis strategies to derive the optimal benefits from the resulting bio-oils. In this thesis, novel pyrolysis strategies were developed that enable efficient utilization of the bio-oils (and/or their vapors) from lignocellulose, algae, as well as oil seed feed stocks. With lignocellulosic feed stocks, pyrolysis of whole biomass as well as the lignin residue left behind following well-established pretreatment and saccharification (i.e., depolymerization of cellulose and hemicellulose to their monomeric-sugars) of the biomass was studied with and without catalysts. Following this, pyrolysis of (lipid-deficient) algae and lignocellulosic feed stocks, under similar reactor conditions, was performed for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from

  6. Simulating pH effects in an algal-growth hydrodynamics model(1).

    PubMed

    James, Scott C; Janardhanam, Vijayasarathi; Hanson, David T

    2013-06-01

    Models and numerical simulations are relatively inexpensive tools that can be used to enhance economic competitiveness through operation and system optimization to minimize energy and resource consumption, while maximizing algal oil yield. This work uses modified versions of the U.S. Environmental Protection Agency's Environmental Fluid Dynamics Code (EFDC) in conjunction with the U.S. Army Corp of Engineers' water-quality code (CE-QUAL) to simulate flow hydrodynamics coupled to algal growth kinetics. The model allows the flexibility of manipulating a host of variables associated with algal growth such as temperature, light intensity, and nutrient availability. pH of the medium is a newly added operational parameter governing algal growth that affects algal photosynthesis, differential availability of inorganic forms of carbon, enzyme activity in algae cell walls, and oil production rates. A single-layer algal-growth/hydrodynamic model without pH limitation was verified by comparing solution curves of algal biomass and phosphorus concentrations to an analytical solution. Media pH, now included in the model as a growth-limiting factor, can be entered as a measured value or calculated based on CO2 concentrations. Upon adding the ability to limit growth due to pH, physically reasonable results have been obtained from the model both with and without pH limitation. When the model was used to simulate algal growth from a pond experiment in the greenhouse, a least-squares fitting technique yielded a maximum algal production (subsequently modulated by limitation factors) of 1.05 d(-1) . Overall, the measured and simulated biomass concentrations in the greenhouse pond were in close agreement. PMID:27007048

  7. Application of NDVI to detecting algal bloom in the Bohai Sea of China from AVHRR

    NASA Astrophysics Data System (ADS)

    Zhao, Dongzhi

    2003-05-01

    This paper analyses the relation between data measured in situ and the NDVI derived from AVHRR of NOAA-14 during algal bloom in the Bohai sea in 1998 to establish surface biomass model of Ceratium furca(EHr.). This model is easy to utilize data received from multi-source satellite in operation, and gets directly the index of phytoplankton biomass. The area and distribution of high biomass is also presented. Based on this model, propagation speed of phytoplankton reveals progress of algal bloom development. The result of this model can discriminate algal bloom water from silt or suspended particle material (SPM).

  8. Algal Biomass Analysis by Laser-Based Analytical Techniques—A Review

    PubMed Central

    Pořízka, Pavel; Prochazková, Petra; Prochazka, David; Sládková, Lucia; Novotný, Jan; Petrilak, Michal; Brada, Michal; Samek, Ota; Pilát, Zdeněk; Zemánek, Pavel; Adam, Vojtěch; Kizek, René; Novotný, Karel; Kaiser, Jozef

    2014-01-01

    Algal biomass that is represented mainly by commercially grown algal strains has recently found many potential applications in various fields of interest. Its utilization has been found advantageous in the fields of bioremediation, biofuel production and the food industry. This paper reviews recent developments in the analysis of algal biomass with the main focus on the Laser-Induced Breakdown Spectroscopy, Raman spectroscopy, and partly Laser-Ablation Inductively Coupled Plasma techniques. The advantages of the selected laser-based analytical techniques are revealed and their fields of use are discussed in detail. PMID:25251409

  9. Impact of harmful algal blooms on several Lake Erie drinking water treatment facilities; methodology considerations

    EPA Science Inventory

    The propagation of cyanbacterial cells and their toxins were investigated at seven drinking water treatment plants (DWTPs) on Lake Erie were investigated with regards to harmful algal bloom (HAB) toxin concentrations, water quality variations in treatment plant influents, and pr...

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

    PubMed

    Taşkan, Ergin

    2016-07-01

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

  11. TRACKING FRESHWATER DIVERSIONS AND ALGAL BLOOMS THAT IMPACT THE NEW ORLEANS STANDARD METROPOLITAN STATISTICAL AREA -

    EPA Science Inventory

    This project will monitor selected water quality parameters, including water temperature, turbidity, salinity, and algal blooms to assess the impacts of freshwater diversions for several selected areas within the New Orleans metropolitan area. The specific areas of study include ...

  12. Determination of Total Carbohydrates in Algal Biomass: Laboratory Analytical Procedure (LAP)

    SciTech Connect

    Van Wychen, S.; Laurens, L. M. L.

    2013-12-01

    This procedure uses two-step sulfuric acid hydrolysis to hydrolyze the polymeric forms of carbohydrates in algal biomass into monomeric subunits. The monomers are then quantified by either HPLC or a suitable spectrophotometric method.

  13. Cyanobacterial-algal cenoses in ordinary chernozems under the impact of different phytoameliorants

    NASA Astrophysics Data System (ADS)

    Dubovik, I. E.; Suyundukov, Ya. T.; Khasanova, R. F.; Shalygina, R. R.

    2016-04-01

    General ecological and taxonomic characteristics of cyanobacterial-algal cenoses in ordinary chernozems under different ameliorative plants (phytoameliorants) were studied in the Trans-Ural region of the Republic of Bashkortostan. A comparative analysis of the taxa of studied cenoses in the soils under leguminous herbs and grasses was performed. The phytoameliorative effect of different herbs and their relationships with cyanobacterial-algal cenoses were examined. Overall, 134 cyanoprokaryotic and algal species belonging to 70 genera, 36 families, 15 orders, and 9 classes were identified. Cyanobacterial-algal cenoses included the divisions of Chlorophyta, Cyanoprokaryota, Xanthophyta, Bacillariophyta, and Euglenophyta. Representatives of Ch-, X-, CF-, and P-forms were the leading ecobiomorphs in the studied cenoses.

  14. Non-conventional approaches to food processing in CELSS, 1. Algal proteins: Characterization and process optimization

    NASA Technical Reports Server (NTRS)

    Nakhost, Z.; Karel, M.; Krukonis, V. J.

    1987-01-01

    Protein isolate obtained from green algae cultivated under controlled conditions was characterized. Molecular weight determination of fractionated algal proteins using SDS-polyacrylamide gel electrophoresis revealed a wide spectrum of molecular weights ranging from 15,000 to 220,000. Isoelectric points of dissociated proteins were in the range of 3.95 to 6.20. Amino acid composition of protein isolate compared favorably with FAO standards. High content of essential amino acids leucine, valine, phenylalanine and lysine make algal protein isolate a high quality component of closed ecological life support system diets. To optimize the removal of algal lipids and pigments supercritical carbon dioxide extraction (with and without ethanol as a co-solvent) was used. Addition of ethanol to supercritical carbon dioxide resulted in more efficient removal of algal lipids and produced protein isolate with a good yield and protein recovery. The protein isolate extracted by the above mixture had an improved water solubility.

  15. Non-conventional approaches to food processing in CELSS. I - Algal proteins: Characterization and process optimization

    NASA Technical Reports Server (NTRS)

    Nakhost, Z.; Karel, M.; Krukonis, V. J.

    1987-01-01

    Protein isolate obtained from green algae (Scenedesmus obliquus) cultivated under controlled conditions was characterized. Molecular weight determination of fractionated algal proteins using SDS-polyacrylamide gel electrophoresis revealed a wide spectrum of molecular weights ranging from 15,000 to 220,000. Isoelectric points of dissociated proteins were in the range of 3.95 to 6.20. Amino acid composition of protein isolate compared favorably with FAO standards. High content of essential amino acids leucine, valine, phenylalanine and lysine makes algal protein isolate a high quality component of CELSS diets. To optimize the removal of algal lipids and pigments supercritical carbon dioxide extraction (with and without ethanol as a co-solvent) was used. Addition of ethanol to supercritical CO2 resulted in more efficient removal of algal lipids and produced protein isolate with a good yield and protein recovery. The protein isolate extracted by the above mixture had an improved water solubility.

  16. Algal Biofuels Factsheet: Long-Term Energy Benefits Drive U.S. Research

    SciTech Connect

    2013-03-04

    Algal biofuels are generating considerable interest around the world. In the United States, they represent promising pathways for helping to meet the biofuel production targets set by the Energy Independence and Security Act of 2007.

  17. Effect of Algal Inoculation on COD and Nitrogen Removal, and Indigenous Bacterial Dynamics in Municipal Wastewater.

    PubMed

    Lee, Jangho; Lee, Jaejin; Shukla, Sudheer Kumar; Park, Joonhong; Lee, Tae Kwon

    2016-05-28

    The effects of algal inoculation on chemical oxygen demand (COD) and total nitrogen (TN) removal, and indigenous bacterial dynamics were investigated in municipal wastewater. Experiments were conducted with municipal wastewater inoculated with either Chlorella vulgaris AG10032, Selenastrum gracile UTEX 325, or Scenedesmus quadricauda AG 10308. C. vulgaris and S. gracile as fast growing algae in municipal wastewater, performed high COD and TN removal in contrast to Sc. quadricauda. The indigenous bacterial dynamics revealed by 16S rRNA gene amplification showed different bacterial shifts in response to different algal inoculations. The dominant bacterial genera of either algal case were characterized as heterotrophic nitrifying bacteria. Our results suggest that selection of indigenous bacteria that symbiotically interact with algal species is important for better performance of wastewater treatment. PMID:26930350

  18. Measurement and Modeling of Algal Biokinetics in Highly EutrophicWaters

    SciTech Connect

    Stringfellow, William T.; Borglin, Sharon E.; Hanlon, Jeremy S.

    2006-04-04

    Excessive growth of suspended algae in eutrophic surface waters can contribute to the degradation of water quality. The objective of this study was to understand the fundamental processes limiting algal growth in highly nutrient-rich agricultural drainage water. Studies examining algal biokinetics (growth rates, yields, and decay) were conducted in a twenty-eight mile long, hydraulically simple, open channel. Algae biokinetics were found to follow a growth limited model,despite monitoring data demonstrating the presence of nutrients at concentrations far in excess of those expected to be limiting. A mechanistic algal biokinetic model was written to assist in data interpretation. Results from the mechanistic model suggested that at different times, soluble phosphate, minerals, and inorganic carbon could limit growth rates, but that growth yield was most likely limited by zooplankton grazing. The implication of these finding for control of algal growth are discussed.

  19. Selective consumption and metabolic allocation of terrestrial and algal carbon determine allochthony in lake bacteria.

    PubMed

    Guillemette, François; Leigh McCallister, S; Del Giorgio, Paul A

    2016-06-01

    Here we explore strategies of resource utilization and allocation of algal versus terrestrially derived carbon (C) by lake bacterioplankton. We quantified the consumption of terrestrial and algal dissolved organic carbon, and the subsequent allocation of these pools to bacterial growth and respiration, based on the δ(13)C isotopic signatures of bacterial biomass and respiratory carbon dioxide (CO2). Our results confirm that bacterial communities preferentially remove algal C from the terrestrially dominated organic C pool of lakes, but contrary to current assumptions, selectively allocate this autochthonous substrate to respiration, whereas terrestrial C was preferentially allocated to biosynthesis. The results provide further evidence of a mechanism whereby inputs of labile, algal-derived organic C may stimulate the incorporation of a more recalcitrant, terrestrial C pool. This mechanism resulted in a counterintuitive pattern of high and relatively constant levels of allochthony (~76%) in bacterial biomass across lakes that otherwise differ greatly in productivity and external inputs. PMID:26623544

  20. Enhancement of Chlorophyll Concentration and Growing Harmful Algal Bloom Along the California Coast

    NASA Astrophysics Data System (ADS)

    Aceves, Joselyn; Singh, Ramesh

    2016-07-01

    We have carried out detailed analysis of satellite and ground data at different locations, Cal Poly, Goleta, Newport, Santa Monica, and Scripps piers and Monterey, Stearns and Santa Cruz wharfs along the California coast for the period 2008-2015. The sea surface temperature and chlorophyll concentrations derived from satellite data are analyzed together with ground observations of nitrogen, phosphorus, domoic acids and harmful algal blooms. The frequency of harmful algal blooms are found to increase in recent years depending upon the enhancement of chlorophyll concentrations and the discharges along the coast and dynamics of the sea surface temperature. The frequency of harmful algal blooms is higher in the northern California compared to southern California. The anthropogenic activities along the coast have increased which are associated with the forest fires and long range transport of dusts from Asia. The aerosol optical depth derived from satellite data during summer months seems to play an important role in the frequency of harmful algal blooms.

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

    PubMed

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

    2015-01-01

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

  2. From benchtop to raceway : spectroscopic signatures of dynamic biological processes in algal communities.

    SciTech Connect

    Trahan, Christine Alexandra; Garcia, Omar Fidel; Martino, Anthony A.; Raymer, Michelle; Collins, Aaron M.; Hanson, David T.; Turner, Tom; Powell, Amy Jo; James, Scott Carlton; Timlin, Jerilyn Ann; Scholle, Steven; Dwyer, Brian P.; Ruffing, Anne; Jones, Howland D. T.; Ricken, James Bryce; Reichardt, Thomas A.

    2010-08-01

    The search is on for new renewable energy and algal-derived biofuel is a critical piece in the multi-faceted renewable energy puzzle. It has 30x more oil than any terrestrial oilseed crop, ideal composition for biodiesel, no competition with food crops, can be grown in waste water, and is cleaner than petroleum based fuels. This project discusses these three goals: (1) Conduct fundamental research into the effects that dynamic biotic and abiotic stressors have on algal growth and lipid production - Genomics/Transcriptomics, Bioanalytical spectroscopy/Chemical imaging; (2) Discover spectral signatures for algal health at the benchtop and greenhouse scale - Remote sensing, Bioanalytical spectroscopy; and (3) Develop computational model for algal growth and productivity at the raceway scale - Computational modeling.

  3. Proterozoic microfossils revealing the time of algal divergences

    NASA Astrophysics Data System (ADS)

    Moczydlowska-Vidal, Malgorzata

    2010-05-01

    Proterozoic microfossils revealing the time of algal divergences Małgorzata Moczydłowska-Vidal Uppsala University, Department of Earth Sciences, Palaeobiology, Villavägen 16, SE 752 36 Uppsala, Sweden (malgo.vidal@pal.uu.se) Morphological and reproductive features and cell wall ultrastructure and biochemistry of Proterozoic acritarchs are used to determine their affinity to modern algae. The first appearance datum of these microbiota is traced to infer a minimum age of the divergence of the algal classes to which they may belong. The chronological appearance of microfossils that represent phycoma-like and zygotic cysts and vegetative cells and/or aplanospores, respectively interpreted as prasinophyceaen and chlorophyceaen microalgae, is related to the Viridiplantae phylogeny. These divergence times differ from molecular clock estimates, and the palaeontological evidence suggests that they are older. The best examples of unicellular, organic-walled microfossils (acritarchs) from the Mesoproterozoic to Early Ordovician are reviewed to demonstrate features, which are indicative of their affinity to photosynthetic microalgae. The first indication that a microfossil may be algal is a decay- and acid-resistant cell wall, which reflects its biochemistry and ultrastructure, and probably indicates the ability to protect a resting/reproductive cyst. The biopolymers synthesized in the cell walls of algae and in land plants ("plant cells"), such as sporopollenin/algaenan, are diagnostic for photosynthetic taxa and were inherited from early unicellular ancestors. These preservable cell walls are resistant to acetolysis, hydrolysis and acids, and show diagnostic ultrastructures such as the trilaminar sheath structure (TLS). "Plant cell" walls differ in terms of chemical compounds, which give high preservation potential, from fungal and animal cell walls. Fungal and animal cells are fossilized only by syngenetic permineralization, whereas "plant cells" are fossilized as body

  4. A Geospatial Analysis of Harmful Algal Blooms along the California Coast

    NASA Astrophysics Data System (ADS)

    Jensen, C.; Rothwell, R.; Johnson, E.; Condamoor, M.; Patil, M.; Largier, J. L.; Schmidt, C.

    2012-12-01

    Algal blooms are natural phenomena consisting of the rapid growth of phytoplankton populations. Some blooms have negative ecological or public health effects due to toxin production and removal of oxygen from the water column. In recent years, such "harmful algal blooms" (HABs) have been linked to human illness, economic loss from decreased fishing, and ecological damage related to marine life mortality as well as eutrophication. A notable HAB event occurred along the coast of northern California in August 2011, resulting in economic and ecological impacts of approximately $82 million. This was one of several algal blooms that occurred in fall 2011, with similar northward propagating algal blooms occurring in autumn of other years. Although the scale of the bloom impact is well-known, the spatial and temporal extent of the bloom boundary is still unclear. This study tracked the space-time pattern of numerous blooms during August-October 2011 using multiple NASA Earth observing systems in an effort to quantify and understand the structure of these recurrent bloom events. Aqua MODIS images were used to quantify surface chlorophyll-α levels, and thus to map the extent and development of all autumn algal blooms. The relation between sea surface temperature, ocean surface topography, and algal blooms was further explored with AVHRR and Jason-2 satellite data. A Generalized Additive Model (GAM) was used to identify the environmental factors most statistically influential in algal blooms and specifically in HAB events. Results from this study will assist California's Departments of Public Health and Fish & Game in mitigating and managing the impact of future harmful algal blooms.

  5. Siliceous algal and bacterial stromatolites in hot spring and geyser effluents of yellowstone national park.

    PubMed

    Walter, M R; Bauld, J; Brock, T D

    1972-10-27

    Growing algal and bacterial stromatolites composed of nearly amorphous silica occur around hot springs and geysers in Yellowstone National Park, Wyoming. Some Precambrian stromatolites may be bacterial rather than algal, which has important implications in atmospheric evolution, since bacterial photo-synthesis does not release oxygen. Conophyton stromatolites were thought to have become extinct at the end of the Precambrian, but are still growing in hot spring effluents. PMID:17815363

  6. Algal Biofuels Strategy. Proceedings from the March 26-27, 2014, Workshop, Charleston, South Carolina

    SciTech Connect

    None, None

    2014-06-01

    This report is based on the proceedings of the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy’s Bioenergy Technologies Office’s Algal Biofuel Strategy Workshop on March 26-27, 2014, in Charleston, South Carolina. The workshop objective was to convene stakeholders to engage in discussion on strategies over the next 5 to 10 years to achieve affordable, scalable, and sustainable algal biofuels.

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

    PubMed

    Kahlert, Maria; McKie, Brendan G

    2014-11-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  9. Direct utilization of waste water algal biomass for ethanol production by cellulolytic Clostridium phytofermentans DSM1183.

    PubMed

    Fathima, Anwar Aliya; Sanitha, Mary; Kumar, Thangarathinam; Iyappan, Sellamuthu; Ramya, Mohandass

    2016-02-01

    Direct bioconversion of waste water algal biomass into ethanol using Clostridium phytofermentans DSM1183 was demonstrated in this study. Fermentation of 2% (w/v) autoclaved algal biomass produced ethanol concentration of 0.52 g L(-1) (solvent yield of 0.19 g/g) where as fermentation of acid pretreated algal biomass (2%, w/v) produced ethanol concentration of 4.6 g L(-1) in GS2 media (solvent yield of 0.26 g/g). The control experiment with 2% (w/v) glucose in GS2 media produced ethanol concentration of 2.8 g L(-1) (solvent yield of 0.25 g/g). The microalgal strains from waste water algal biomass were identified as Chlamydomonas dorsoventralis, Graesiella emersonii, Coelastrum proboscideum, Scenedesmus obliquus, Micractinium sp., Desmodesmus sp., and Chlorella sp., based on ITS-2 molecular marker. The presence of glucose, galactose, xylose and rhamnose were detected by high performance liquid chromatography in the algal biomass. Scanning Electron Microscopy observations of fermentation samples showed characteristic morphological changes in algal cells and bioaccessibility of C. phytofermentans. PMID:26705954

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

    PubMed

    Zuo, Shengpeng; Wan, Kun; Ma, Sumin

    2015-01-01

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

  11. Emerging contaminant degradation and removal in algal wastewater treatment ponds: Identifying the research gaps.

    PubMed

    Norvill, Zane N; Shilton, Andy; Guieysse, Benoit

    2016-08-01

    Whereas the fate of emerging contaminants (ECs) during 'conventional' and 'advanced' wastewater treatment (WWT) has been intensively studied, little research has been conducted on the algal WWT ponds commonly used in provincial areas. The long retention times and large surface areas exposed to light potentially allow more opportunities for EC removal to occur, but experimental evidence is lacking to enable definite predictions about EC fate across different algal WWT systems. This study reviews the mechanisms of EC hydrolysis, sorption, biodegradation, and photodegradation, applying available knowledge to the case of algal WWT. From this basis the review identifies three main areas that need more research due to the unique environmental and ecological conditions occurring in algal WWT ponds: i) the effect of diurnally fluctuating pH and dissolved oxygen upon removal mechanisms; ii) the influence of algae and algal biomass on biodegradation and sorption under relevant conditions; and iii) the significance of EC photodegradation in the presence of dissolved and suspended materials. Because of the high concentration of dissolved organics typically found in algal WWT ponds, most EC photodegradation likely occurs via indirect mechanisms rather than direct photolysis in these systems. PMID:27135171

  12. Investigating why recycling gravity harvested algae increases harvestability and productivity in high rate algal ponds.

    PubMed

    Park, J B K; Craggs, R J; Shilton, A N

    2013-09-15

    It has previously been shown that recycling gravity harvested algae promotes Pediastrum boryanum dominance and improves harvestability and biomass production in pilot-scale High Rate Algal Ponds (HRAPs) treating domestic wastewater. In order to confirm the reproducibility of these findings and investigate the mechanisms responsible, this study utilized twelve 20 L outdoor HRAP mesocosms operated with and without algal recycling. It then compared the recycling of separated solid and liquid components of the harvested biomass against un-separated biomass. The work confirmed that algal recycling promoted P. boryanum dominance, improved 1 h-settleability by >20% and increased biomass productivity by >25% compared with controls that had no recycling. With regard to the improved harvestability, of particular interest was that recycling the liquid fraction alone caused a similar improvement in settleability as recycling the solid fraction. This may be due to the presence of extracellular polymeric substances in the liquid fraction. While there are many possible mechanisms that could account for the increased productivity with algal recycling, all but two were systematically eliminated: (i) the mean cell residence time was extended thereby increasing the algal concentration and more fully utilizing the incident sunlight and, (ii) the relative proportions of algal growth stages (which have different specific growth rates) was changed, resulting in a net increase in the overall growth rate of the culture. PMID:23866138

  13. Significance of cyclic Pennsylvanian-Permian coral/algal buildups Snaky Canyon

    SciTech Connect

    Canter, K.L. ); Isaacson, P.E. )

    1991-02-01

    Five cyclic algal, hydrozoan, and coral buildups occur within a thick sequence of Pennsylvanian-Permian (Virgilian through Wolfcampain) carbonates in south-central Idaho. The Juniper Gulch Member of the Snaky Canyon Formation, as described by Skipp and coworkers, is approximately 600 m thick and contains four depositional facies, including: (1) open circulation outer( ) platform, (2) hydrozoan and phylloid algal mound-dominated carbonate buildup, (3) backmound, restricted platform/lagoon, and (4) restricted inner platform facies. Several microlithofacies, including lime mud-rich bafflestone, diversely fossiliferous packstone and grainstone, bryozoan lime floatstone, and phylloid algal and hydrozoan (Palaeoaplysina) lime bindstone are described within the phylloid algal mounds. Successional faunal assemblage stages are recognized within the buildups. Colonial rugose corals comprise a stabilization stage. When the algal communities of the diversification stage reached wave base, because of their rapid upward growth, cross-bedded oolitic grainstone and occasional cross-bedded dolomite shoals developed. Supratidal to high intertidal platform sedimentation is represented by dolomitic Palaeoaplysina bindstone, algal mat bindstone, and vuggy dolomite. Five vertical sequences of buildup development, each terminate by intertidal, supratidal, or erosional events, are seen in the Juniper Gulch Member in the North Howe stratigraphic section of the southern Lost River Range. The carbonate platform was constructed within a depositional basin that includes an eroded highland to the west, and a mixed siliciclastic-carbonate inner platform with craton uplifts to the east.

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

    PubMed Central

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

    2013-01-01

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

  15. Advancing Commercialization of Algal Biofuels Through Increased Biomass Productivity and Technology Integration

    SciTech Connect

    Bai, Xuemei; Sabarsky, Martin

    2013-09-30

    Cellana is a leading developer of algae-based bioproducts, and its pre-commercial production of marine microalgae takes place at Cellana?s Kona Demonstration Facility (KDF) in Hawaii. KDF is housing more than 70 high-performing algal strains for different bioproducts, of which over 30 have been grown outside at scale. So far, Cellana has produced more than 10 metric tons of algal biomass for the development of biofuels, animal feed, and high-value nutraceuticals. Cellana?s ALDUO algal cultivation technology allows Cellana to grow non-extremophile algal strains at large scale with no contamination disruptions. Cellana?s research and production at KDF have addressed three major areas that are crucial for the commercialization of algal biofuels: yield improvement, cost reduction, and the overall economics. Commercially acceptable solutions have been developed and tested for major factors limiting areal productivity of algal biomass and lipids based on years of R&D work conducted at KDF. Improved biomass and lipid productivity were achieved through strain improvement, culture management strategies (e.g., alleviation of self-shading, de-oxygenation, and efficient CO2 delivery), and technical advancement in downstream harvesting technology. Cost reduction was achieved through optimized CO2 delivery system, flue gas utilization technology, and energy-efficient harvesting technology. Improved overall economics was achieved through a holistic approach by integration of high-value co-products in the process, in addition to yield improvements and cost reductions.

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

    PubMed

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

    2009-01-01

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

  17. Micropollutant removal in an algal treatment system fed with source separated wastewater streams.

    PubMed

    de Wilt, Arnoud; Butkovskyi, Andrii; Tuantet, Kanjana; Leal, Lucia Hernandez; Fernandes, Tânia V; Langenhoff, Alette; Zeeman, Grietje

    2016-03-01

    Micropollutant removal in an algal treatment system fed with source separated wastewater streams was studied. Batch experiments with the microalgae Chlorella sorokiniana grown on urine, anaerobically treated black water and synthetic urine were performed to assess the removal of six spiked pharmaceuticals (diclofenac, ibuprofen, paracetamol, metoprolol, carbamazepine and trimethoprim). Additionally, incorporation of these pharmaceuticals and three estrogens (estrone, 17β-estradiol and ethinylestradiol) into algal biomass was studied. Biodegradation and photolysis led to 60-100% removal of diclofenac, ibuprofen, paracetamol and metoprolol. Removal of carbamazepine and trimethoprim was incomplete and did not exceed 30% and 60%, respectively. Sorption to algal biomass accounted for less than 20% of the micropollutant removal. Furthermore, the presence of micropollutants did not inhibit C. sorokiniana growth at applied concentrations. Algal treatment systems allow simultaneous removal of micropollutants and recovery of nutrients from source separated wastewater. Nutrient rich algal biomass can be harvested and applied as fertilizer in agriculture, as lower input of micropollutants to soil is achieved when algal biomass is applied as fertilizer instead of urine. PMID:26546707

  18. Toxicologic evaluation of DHA-rich algal oil: Genotoxicity, acute and subchronic toxicity in rats.

    PubMed

    Schmitt, D; Tran, N; Peach, J; Bauter, M; Marone, P

    2012-10-01

    DHA-rich algal oil ONC-T18, tested in a battery of in vitro and in vivo genotoxicity tests, did not show mutagenic or genotoxic potential. The acute oral LD50 in rats has been estimated to be greater than 5000 mg/kg of body weight. In a 90-day subchronic dietary study, administration of DHA-rich algal oil at concentrations of 0, 10,000, 25,000, and 50,000 ppm in the diet for 13 weeks did not produce any significant toxicologic manifestations. The algal oil test article was well tolerated as evidenced by the absence of major treatment-related changes in the general condition and appearance of the rats, neurobehavioral endpoints, growth, feed and water intake, ophthalmoscopic examinations, routine hematology and clinical chemistry parameters, urinalysis, or necropsy findings. The no observed adverse effect level (NOAEL) was the highest level fed of 50,000 ppm which is equivalent to 3,305 and 3,679 mg/kg bw/day, for male and female rats, respectively. The studies were conducted as part of an investigation to examine the safety of DHA-rich algal oil. The results confirm that it possesses a toxicity profile similar to other currently marketed algal oils and support the safety of DHA-rich algal oil for its proposed use in food. PMID:22898615

  19. Safety evaluation of DHA-rich Algal Oil from Schizochytrium sp.

    PubMed

    Fedorova-Dahms, I; Marone, P A; Bauter, M; Ryan, A S

    2011-12-01

    The safety of DHA-rich Algal Oil from Schizochytrium sp. containing 40-45 wt% DHA and up to 10 wt% EPA was evaluated by testing for gene mutations, clastogenicity and aneugenicity, and in a subchronic 90-day Sprague-Dawley rat dietary study with in utero exposure, followed by a 4-week recovery phase. The results of all genotoxicity tests were negative. In the 90-day study, DHA-rich Algal Oil was administered at dietary levels of 0.5, 1.5, and 5 wt% along with two control diets: a standard low-fat basal diet and a basal diet supplemented with 5 wt% of concentrated Fish Oil. There were no treatment-related effects of DHA-rich Algal Oil on clinical observations, body weight, food consumption, behavior, hematology, clinical chemistry, coagulation, or urinalysis. Increases in absolute and relative weights of the liver, kidney, spleen and adrenals (adrenals and spleen with histological correlates) were observed in both the Fish Oil- and the high-dose of DHA-rich Algal Oil-treated females and were not considered to be adverse. The no observed adverse effect level (NOAEL) for DHA-rich Algal Oil under the conditions of this study was 5 wt% in the diet, equivalent to an overall average DHA-rich Algal Oil intake of 4260 mg/kg bw/day for male and female rats. PMID:21914458

  20. Carbon and nutrient removal from centrates and domestic wastewater using algal-bacterial biofilm bioreactors.

    PubMed

    Posadas, Esther; García-Encina, Pedro-Antonio; Soltau, Anna; Domínguez, Antonio; Díaz, Ignacio; Muñoz, Raúl

    2013-07-01

    The mechanisms of carbon and nutrient removal in an open algal-bacterial biofilm reactor and an open bacterial biofilm reactor were comparatively evaluated during the treatment of centrates and domestic wastewater. Comparable carbon removals (>80%) were recorded in both bioreactors, despite the algal-bacterial biofilm supported twice higher nutrient removals than the bacterial biofilm. The main carbon and nitrogen removal mechanisms in the algal-bacterial photobioreactor were assimilation into algal biomass and stripping, while stripping accounted for most carbon and nitrogen removal in the bacterial biofilm. Phosphorus was removed by assimilation into algal-bacterial biomass while no effective phosphorous removal was observed in the bacterial biofilm. Carbon, nitrogen and phosphorus removals of 91 ± 3%, 70 ± 8% and 85 ± 9%, respectively, were recorded in the algal-bacterial bioreactor at 10d of hydraulic retention time when treating domestic wastewater. However, the high water footprint recorded (0.5-6.7 Lm(-2)d(-1)) could eventually compromise the environmental sustainability of this microalgae-based technology. PMID:23644070

  1. Textural variation within Great Salt Lake algal mounds: Chapter 8.5 in Stromatolites

    USGS Publications Warehouse

    1976-01-01

    This chapter discusses textural variation within the Great Salt Lake algal mounds. Great Salt Lake algal mounds contain: (1) a framework of non-skeletal, algally induced aragonite precipitates; (2) internal sediment; and (3) inorganic cement. These three elements create a variety of laminated, poorly laminated, and unlaminated internal textures. Interior framework precipitates bear little resemblance to the present living film of the mound surface. Internal texture of the mounds is believed to be largely relict and to have resulted from precipitation by algae different than those presently living at the surface. The most probable cause of local extinction of the algal flora is change in brine salinity. Precipitated blue-green algal structures in ancient rocks may indicate other than normal marine salinity and near shore sedimentation. Extreme variation of internal texture reflects extreme environmental variability typical of closed basin lakes. Recognition of mounds similar to those in the Great Salt Lake can be a first step toward recognition of ancient hyper-saline lake deposits, if such an interpretation is substantiated by consideration of the entire depositional milieu of precipitated algal mounds.

  2. Effects of four rice paddy herbicides on algal cell viability and the relationship with population recovery.

    PubMed

    Nagai, Takashi; Ishihara, Satoru; Yokoyama, Atsushi; Iwafune, Takashi

    2011-08-01

    Paddy herbicides are a high-risk concern for aquatic plants, including algae, because they easily flow out from paddy fields into rivers, with toxic effects. The effect on algal population dynamics, including population recovery after timed exposure, must be assessed. Therefore, we demonstrated concentration-response relationships of four paddy herbicides for algal growth inhibition and mortality, and the relationship between the effect on algal cell viability and population recovery following exposure. We used SYTOX Green dye assay and flow cytometry to assess cell viability of the alga Pseudokirchneriella subcapitata. Live cells could be clearly distinguished from dead cells during herbicide exposure. Our results showed that pretilachlor and quinoclamine had both algicidal and algistatic effects, whereas bensulfuron-methyl only had an algistatic effect, and pentoxazone only had an algicidal effect. Then, a population recovery test following a 72-h exposure was conducted. The algal population recovered in all tests, but the periods required for recovery differed among exposure concentrations and herbicides. The periods required for recovery were inconsistent with the dead cell ratio at the beginning of the recovery test; that is, population recovery could not be described only by cell viability. Consequently, the temporal effect of herbicides and subsequent recovery of the algal population could be described not only by the toxicity characteristics but also by toxicokinetics, such as rate of uptake, transport to the target site, and elimination of the substance from algal cells. PMID:21590715

  3. Malt house wastewater treatment with settleable algal-bacterial flocs.

    PubMed

    Stříteský, Luboš; Pešoutová, Radka; Hlavínek, Petr

    2015-01-01

    This paper deals with biological treatment of malt house wastewater using algal-bacterial flocs. During three months of testing, optimisation of growth conditions and biomass separation leads to maximisation of biomass production, improved flocs settleability and increased pollutant removal efficiency while maintaining low energy demand. At a high food to microorganism ratio (0.16 to 0.29 kg BOD5 kg(-1) TSS d(-1)), the biological oxygen demand (BOD5), chemical oxygen demand (CODCr), total phosphorus (Ptot) and total suspended solids (TSS) removal efficiencies were all higher than 90%. At a food to microorganism ratio of 0.06 kg BOD5 kg(-1) TSS d(-1), BOD5, CODCr, total nitrogen (Ntot), Ptot and TSS removal efficiencies of 99.5%, 97.6%, 91.5%, 97.8% and 98.4%, respectively, were achieved. The study also proved a strong dependence of removal efficiencies on solar radiation. The results suggest the algae-bacteria system is suitable for treatment of similar wastewater in locations with available land and sufficient solar radiation and temperature during the whole year. PMID:26540541

  4. Environmental indicators for sustainable production of algal biofuels

    DOE PAGESBeta

    Efroymson, Rebecca A.; Dale, Virginia H.

    2014-10-01

    For analyzing sustainability of algal biofuels, we identify 16 environmental indicators that fall into six categories: soil quality, water quality and quantity, air quality, greenhouse gas emissions, biodiversity, and productivity. Indicators are selected to be practical, widely applicable, predictable in response, anticipatory of future changes, independent of scale, and responsive to management. Major differences between algae and terrestrial plant feedstocks, as well as their supply chains for biofuel, are highlighted, for they influence the choice of appropriate sustainability indicators. Algae strain selection characteristics do not generally affect which indicators are selected. The use of water instead of soil as themore » growth medium for algae determines the higher priority of water- over soil-related indicators. The proposed set of environmental indicators provides an initial checklist for measures of biofuel sustainability but may need to be modified for particular contexts depending on data availability, goals of the stakeholders, and financial constraints. Ultimately, use of these indicators entails defining sustainability goals and targets in relation to stakeholder values in a particular context and can lead to improved management practices.« less

  5. Lifespan extension of rotifers by treatment with red algal extracts

    PubMed Central

    Snare, David J.; Fields, Allison M.; Snell, Terry W.; Kubanek, Julia

    2013-01-01

    Aging results from an accumulation of damage to macromolecules inhibiting cellular replication, repair, and other necessary functions. Damage may be due to environmental stressors such as metal toxicity, oxidative stress caused by imperfections in electron transfer reactions, or other metabolic processes. In an effort to discover medical treatments that counteract this damage, we initiated a search for small molecule drugs from natural sources using life table experiments which, through their unbiased approach, present the opportunity to discover first-in-class molecules. We have identified marine red algae as a source of natural products that slow aging of the invertebrate rotifer Brachionus manjavacas. Rotifers are a promising model organism for life extension studies as they maintain a short, measurable lifespan while also having an extensive literature related to aging. Rotifer lifespan was increased 9–14% by exposure to three of a total of 200 screened red algal extracts. Bioassay guided fractionation led to semi-purified extracts composed primarily of lipids responsible for rotifer life extension. The life extending mixture from the red alga Acanthophora spicifera contained eicosanoic, octadecanoic, and hexadecanoic acids as well as several unidentified unsaturated fatty acids. The life extending effects of these small molecule mixtures are not a result of their direct antioxidant capacity; other unknown mechanisms of action are likely involved. An understanding of how these natural products interact with their molecular targets could lead to selective and effective treatments for slowing aging and reducing age related diseases. PMID:24120568

  6. Dynamic mathematical model of high rate algal ponds (HRAP).

    PubMed

    Jupsin, H; Praet, E; Vasel, J L

    2003-01-01

    This article presents a mathematical model to describe High-Rate Algal Ponds (HRAPs). The hydrodynamic behavior of the reactor is described as completely mixed tanks in series with recirculation. The hydrodynamic pattern is combined with a subset of River Water Quality Model 1 (RWQM1), including the main processes in liquid phase. Our aim is to develop models for WSPs and aerated lagoons, too, but we focused on HRAPs first for several reasons: Sediments are usually less abundant in HRAP and can be neglected, Stratification is not observed and state variables are constant in a reactor cross section, Due to the system's geometry, the reactor is quite similar to a plugflow type reactor with recirculation, with a simple advection term. The model is based on mass balances and includes the following processes: *Phytoplankton growth with NO3-, NO2- and death, *Aerobic growth of heterotrophs with NO3-, NH4+ and respiration, *Anoxic growth of heterotrophs with NO3-, NO2- and anoxic respiration, *Growth of nitrifiers (two stages) and respiration. The differences with regard to RWQM1 are that we included a limiting term associated with inorganic carbon on the growth rate of algae and nitrifiers, gas transfers are taken into account by the familiar Adeney equation, and a subroutine calculates light intensity at the water surface. This article presents our first simulations. PMID:14510211

  7. Environmental indicators for sustainable production of algal biofuels

    SciTech Connect

    Efroymson, Rebecca A.; Dale, Virginia H.

    2014-10-01

    For analyzing sustainability of algal biofuels, we identify 16 environmental indicators that fall into six categories: soil quality, water quality and quantity, air quality, greenhouse gas emissions, biodiversity, and productivity. Indicators are selected to be practical, widely applicable, predictable in response, anticipatory of future changes, independent of scale, and responsive to management. Major differences between algae and terrestrial plant feedstocks, as well as their supply chains for biofuel, are highlighted, for they influence the choice of appropriate sustainability indicators. Algae strain selection characteristics do not generally affect which indicators are selected. The use of water instead of soil as the growth medium for algae determines the higher priority of water- over soil-related indicators. The proposed set of environmental indicators provides an initial checklist for measures of biofuel sustainability but may need to be modified for particular contexts depending on data availability, goals of the stakeholders, and financial constraints. Ultimately, use of these indicators entails defining sustainability goals and targets in relation to stakeholder values in a particular context and can lead to improved management practices.

  8. Algal resistance to herbivory on a Caribbean barrier reef

    NASA Astrophysics Data System (ADS)

    Littler, Mark M.; Taylor, Phillip R.; Littler, Diane S.

    1983-06-01

    Field and laboratory research at Carrie Bow Cay, Belize showed that macroalgae, grouped in functional-form units resisted fish and urchin herbivory in the following order (from high to low resistance): Crustose-Group, Jointed Calcareous-Group, Thick Leathery-Group, Coarsely Branched-Group, Filamentous-Group and Sheet-Group; thereby supporting the hypothesis that crustose, calcareous and thick algae have evolved antipredator defenses and should show the greatest resistance to herbivory with a gradation of increasing palatability towards filaments and sheets. Of the 21 species examined, several (e.g., Dictyota cervicornis on grids, Laurencia obtusa and Stypopodium zonale) had exceptionally low losses to fish grazing, probably due to chemical defences. The sea urchin, Diadema antillarum, was more inclined to feed on algae with known toxic secondary metabolites than were herbivorous fishes; hypothetically related to the differences in mobility and concomitant modes of feeding. Tough leathery forms such as Sargassum polyceratium and Turbinaria turbinata resisted grazing by bottom feeding parrotfishes (Scaridae) and surgeonfishes (Acanthuridae) but were susceptible when suspended midway in the water column, possibly due to the presence of rudderfishes (Kyphosidae) which readily consume drift Sargassaceae. The overall tendencies support our predicted relationship between grazer-resistance and algal morphology. In conjunction with our previously reported findings concerning primary productivity, toughness and calorimetry for many of the same species, these results lend credence to generalizations relating form with function in marine macroalgae.

  9. Parasitic chytrids sustain zooplankton growth during inedible algal bloom

    PubMed Central

    Rasconi, Serena; Grami, Boutheina; Niquil, Nathalie; Jobard, Marlène; Sime-Ngando, Télesphore

    2014-01-01

    This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of “inedible” algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19–20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the zooplankton diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin. PMID:24904543

  10. Pyrolysis kinetics of algal consortia grown using swine manure wastewater.

    PubMed

    Sharara, Mahmoud A; Holeman, Nathan; Sadaka, Sammy S; Costello, Thomas A

    2014-10-01

    In this study, pyrolysis kinetics of periphytic microalgae consortia grown using swine manure slurry in two seasonal climatic patterns in northwest Arkansas were investigated. Four heating rates (5, 10, 20 and 40 °C min(-1)) were used to determine the pyrolysis kinetics. Differences in proximate, ultimate, and heating value analyses reflected variability in growing substrate conditions, i.e., flocculant use, manure slurry dilution, and differences in diurnal solar radiation and air temperature regimes. Peak decomposition temperature in algal harvests varied with changing the heating rate. Analyzing pyrolysis kinetics using differential and integral isoconversional methods (Friedman, Flynn-Wall-Ozawa, and Kissinger-Akahira-Sunose) showed strong dependency of apparent activation energy on the degree of conversion suggesting parallel reaction scheme. Consequently, the weight loss data in each thermogravimetric test was modeled using independent parallel reactions (IPR). The quality of fit (QOF) for the model ranged between 2.09% and 3.31% indicating a good agreement with the experimental data. PMID:25105272

  11. In vivo Reconstitution of Algal Triacylglycerol Production in Saccharomyces cerevisiae

    PubMed Central

    Hung, Chun-Hsien; Kanehara, Kazue; Nakamura, Yuki

    2016-01-01

    The current fascination with algal biofuel production stems from a high lipid biosynthetic capacity and little conflict with land plant cultivation. However, the mechanisms which enable algae to accumulate massive oil remain elusive. An enzyme for triacylglycerol (TAG) biosynthesis in Chlamydomonas reinhardtii, CrDGTT2, can produce a large amount of TAG when expressed in yeast or higher plants, suggesting a unique ability of CrDGTT2 to enhance oil production in a heterologous system. Here, we performed metabolic engineering in Saccharomyces cerevisiae by taking advantage of CrDGTT2. We suppressed membrane phospholipid biosynthesis at the log phase by mutating OPI3, enhanced TAG biosynthetic pathway at the stationary phase by overexpressing PAH1 and CrDGTT2, and suppressed TAG hydrolysis on growth resumption from the stationary phase by knocking out DGK1. The resulting engineered yeast cells accumulated about 70-fold of TAG compared with wild type cells. Moreover, TAG production was sustainable. Our results demonstrated the enhanced and sustainable TAG production in the yeast synthetic platform. PMID:26913021

  12. Intraspecific Diversity and Ecological Zonation in Coral-Algal Symbiosis

    NASA Astrophysics Data System (ADS)

    Rowan, Rob; Knowlton, Nancy

    1995-03-01

    All reef-building corals are obligately associated with photosynthetic microalgal endosymbionts called zooxanthellae. Zooxanthella taxonomy has emphasized differences between species of hosts, but the possibility of ecologically significant zooxanthella diversity within hosts has been the subject of speculation for decades. Analysis of two dominant Caribbean corals showed that each associates with three taxa of zooxanthellae that exhibit zonation with depth-the primary environmental gradient for light-dependent marine organisms. Some colonies apparently host two taxa of symbionts in proportions that can vary across the colony. This common occurrence of polymorphic, habitat-specific symbioses challenges conventional understanding of the units of biodiversity but also illuminates many distinctive aspects of marine animal-algal associations. Habitat specificity provides ecological explanations for the previously documented poor concordance between host and symbiont phylogenies and the otherwise surprising lack of direct, maternal transmission of symbionts in many species of hosts. Polymorphic symbioses may underlie the conspicuous and enigmatic variability characteristic of responses to environmental stress (e.g., coral "bleaching") and contribute importantly to the phenomenon of photoadaptation.

  13. Parasitic chytrids sustain zooplankton growth during inedible algal bloom.

    PubMed

    Rasconi, Serena; Grami, Boutheina; Niquil, Nathalie; Jobard, Marlène; Sime-Ngando, Télesphore

    2014-01-01

    This study assesses the quantitative impact of parasitic chytrids on the planktonic food web of two contrasting freshwater lakes during different algal bloom situations. Carbon-based food web models were used to investigate the effects of chytrids during the spring diatom bloom in Lake Pavin (oligo-mesotrophic) and the autumn cyanobacteria bloom in Lake Aydat (eutrophic). Linear inverse modeling was employed to estimate undetermined flows in both lakes. The Monte Carlo Markov chain linear inverse modeling procedure provided estimates of the ranges of model-derived fluxes. Model results confirm recent theories on the impact of parasites on food web function through grazers and recyclers. During blooms of "inedible" algae (unexploited by planktonic herbivores), the epidemic growth of chytrids channeled 19-20% of the primary production in both lakes through the production of grazer exploitable zoospores. The parasitic throughput represented 50% and 57% of the zooplankton diet, respectively, in the oligo-mesotrophic and in the eutrophic lakes. Parasites also affected ecological network properties such as longer carbon path lengths and loop strength, and contributed to increase the stability of the aquatic food web, notably in the oligo-mesotrophic Lake Pavin. PMID:24904543

  14. Hydrogen production from algal biomass via steam gasification.

    PubMed

    Duman, Gozde; Uddin, Md Azhar; Yanik, Jale

    2014-08-01

    Algal biomasses were tested as feedstock for steam gasification in a dual-bed microreactor in a two-stage process. Gasification experiments were carried out in absence and presence of catalyst. The catalysts used were 10% Fe₂O₃-90% CeO₂ and red mud (activated and natural forms). Effects of catalysts on tar formation and gasification efficiencies were comparatively investigated. It was observed that the characteristic of algae gasification was dependent on its components and the catalysts used. The main role of the catalyst was reforming of the tar derived from algae pyrolysis, besides enhancing water gas shift reaction. The tar reduction levels were in the range of 80-100% for seaweeds and of 53-70% for microalgae. Fe₂O₃-CeO₂ was found to be the most effective catalyst. The maximum hydrogen yields obtained were 1036 cc/g algae for Fucus serratus, 937 cc/g algae for Laminaria digitata and 413 cc/g algae for Nannochloropsis oculata. PMID:24880809

  15. Algal ancestor of land plants was preadapted for symbiosis.

    PubMed

    Delaux, Pierre-Marc; Radhakrishnan, Guru V; Jayaraman, Dhileepkumar; Cheema, Jitender; Malbreil, Mathilde; Volkening, Jeremy D; Sekimoto, Hiroyuki; Nishiyama, Tomoaki; Melkonian, Michael; Pokorny, Lisa; Rothfels, Carl J; Sederoff, Heike Winter; Stevenson, Dennis W; Surek, Barbara; Zhang, Yong; Sussman, Michael R; Dunand, Christophe; Morris, Richard J; Roux, Christophe; Wong, Gane Ka-Shu; Oldroyd, Giles E D; Ané, Jean-Michel

    2015-10-27

    Colonization of land by plants was a major transition on Earth, but the developmental and genetic innovations required for this transition remain unknown. Physiological studies and the fossil record strongly suggest that the ability of the first land plants to form symbiotic associations with beneficial fungi was one of these critical innovations. In angiosperms, genes required for the perception and transduction of diffusible fungal signals for root colonization and for nutrient exchange have been characterized. However, the origin of these genes and their potential correlation with land colonization remain elusive. A comprehensive phylogenetic analysis of 259 transcriptomes and 10 green algal and basal land plant genomes, coupled with the characterization of the evolutionary path leading to the appearance of a key regulator, a calcium- and calmodulin-dependent protein kinase, showed that the symbiotic signaling pathway predated the first land plants. In contrast, downstream genes required for root colonization and their specific expression pattern probably appeared subsequent to the colonization of land. We conclude that the most recent common ancestor of extant land plants and green algae was preadapted for symbiotic associations. Subsequent improvement of this precursor stage in early land plants through rounds of gene duplication led to the acquisition of additional pathways and the ability to form a fully functional arbuscular mycorrhizal symbiosis. PMID:26438870

  16. Algal ancestor of land plants was preadapted for symbiosis

    PubMed Central

    Delaux, Pierre-Marc; Radhakrishnan, Guru V.; Jayaraman, Dhileepkumar; Cheema, Jitender; Malbreil, Mathilde; Volkening, Jeremy D.; Sekimoto, Hiroyuki; Nishiyama, Tomoaki; Melkonian, Michael; Pokorny, Lisa; Rothfels, Carl J.; Sederoff, Heike Winter; Stevenson, Dennis W.; Surek, Barbara; Zhang, Yong; Sussman, Michael R.; Dunand, Christophe; Morris, Richard J.; Roux, Christophe; Wong, Gane Ka-Shu; Oldroyd, Giles E. D.; Ané, Jean-Michel

    2015-01-01

    Colonization of land by plants was a major transition on Earth, but the developmental and genetic innovations required for this transition remain unknown. Physiological studies and the fossil record strongly suggest that the ability of the first land plants to form symbiotic associations with beneficial fungi was one of these critical innovations. In angiosperms, genes required for the perception and transduction of diffusible fungal signals for root colonization and for nutrient exchange have been characterized. However, the origin of these genes and their potential correlation with land colonization remain elusive. A comprehensive phylogenetic analysis of 259 transcriptomes and 10 green algal and basal land plant genomes, coupled with the characterization of the evolutionary path leading to the appearance of a key regulator, a calcium- and calmodulin-dependent protein kinase, showed that the symbiotic signaling pathway predated the first land plants. In contrast, downstream genes required for root colonization and their specific expression pattern probably appeared subsequent to the colonization of land. We conclude that the most recent common ancestor of extant land plants and green algae was preadapted for symbiotic associations. Subsequent improvement of this precursor stage in early land plants through rounds of gene duplication led to the acquisition of additional pathways and the ability to form a fully functional arbuscular mycorrhizal symbiosis. PMID:26438870

  17. Algal biomass and primary production within a temperate zone sandstone

    SciTech Connect

    Bell, R.A.; Sommerfeld, M.R. )

    1987-02-01

    The use of dimethyl sulfoxide (DMSO) to extract chlorophyll a and {sup 14}C-labelled photosynthate from endolithic algae of sparsely vegetated, cold temperate grasslands on the Colorado Plateau in Arizona has yielded the first estimates of biomass and photosynthesis for this unusual community. These subsurface microorganisms are found widespread in exposed Coconino Sandstone, a predominant formation in this cold temperate region. The endolithic community in Coconino Sandstone, composed primarily of coccoid blue-green and coccoid/sarcinoid green algae, yielded a biomass value (as chlorophyll a content) of 87 mg m{sup {minus}2} rock surface area and a photosynthetic rate of 0.37 mg CO{sub 2} dm{sup {minus}2} hr{sup {minus}1} or 0.48 mg CO{sub 2} mg{sup {minus}1} chl a hr{sup {minus}1}. The endolithic algal community contributes moderate biomass (5-10%) and substantial photosynthesis (20-80%) to the sparse grassland ecosystem.

  18. Expanding Fungal Diets Through Synthetic Algal-Fungal Mutualism

    NASA Technical Reports Server (NTRS)

    Sharma, Alaisha; Galazka, Jonathan (Editor)

    2015-01-01

    Fungi can synthesize numerous molecules with important properties, and could be valuable production platforms for space exploration and colonization. However, as heterotrophs, fungi require reduced carbon. This limits their efficiency in locations such as Mars, where reduced carbon is scarce. We propose a system to induce mutualistic symbiosis between the green algae Chlamydomonas reinhardtii and the filamentous fungi Neurospora crassa. This arrangement would mimic natural algal-fungal relationships found in lichens, but have added advantages including increased growth rate and genetic tractability. N. crassa would metabolize citrate (C6H5O7 (sup -3)) and release carbon dioxide (CO2) that C. reinhardtii would assimilate into organic sugars during photosynthesis. C. reinhardtii would metabolize nitrate (NO3-) and release ammonia (NH3) as a nitrogen source for N. crassa. A N. crassa mutant incapable of reducing nitrate will be used to force this interaction. This system eliminates the need to directly supply its participants with carbon dioxide and ammonia. Furthermore, the release of oxygen by C. reinhardtii via photosynthesis would enable N. crassa to respire. We hope to eventually create a system closer to lichen, in which the algae transfers not only nitrogen but reduced carbon, as organic sugars, to the fungus for growth and production of valuable compounds.

  19. Characteristics of turbulent boundary layer flow over algal biofilm

    NASA Astrophysics Data System (ADS)

    Murphy, Elizabeth; Barros, Julio; Schultz, Michael; Steppe, Cecily; Flack, Karen; Reidenbach, Matthew

    2015-11-01

    Algal biofilms are an important fouling community on ship hulls, with severe economic consequences due to drag-induced increases in fuel use and cleaning costs. Here, we characterize the boundary layer flow structure in turbulent flow over diatomaceous slime, a type of biofilm. Diatomaceous slime composed of three species of diatoms commonly found on ship hulls was grown on acrylic test plates under shear stress. The slime averages 1.6 mm in thickness and has a high density of streamers, which are flexible elongated growths with a length on the order of 1- 2 mm located at the top of the biofilm that interact with the flow. Fouled acrylic plates were placed in a water tunnel facility specialized for detailed turbulent boundary layer measurements. High resolution Particle Image Velocimetry (PIV) data are analyzed for mean velocity profile as well as local turbulent stresses and turbulent kinetic energy (TKE) production, dissipation and transport. Quadrant analysis is used to characterize the impact of the instantaneous events of Reynolds shear stress (RSS) in the flow. To investigate the coherence of the large-scale motion in the flow two-point correlation analysis is employed. Funding provided by the Office of Naval Research and the National Science Foundation.

  20. Strategies for optimizing algal biology for enhanced biomass production

    SciTech Connect

    Barry, Amanda N.; Starkenburg, Shawn R.; Sayre, Richard T.

    2015-02-02

    One of the most environmentally sustainable ways to produce high-energy density (oils) feed stocks for the production of liquid transportation fuels is from biomass. Photosynthetic carbon capture combined with biomass combustion (point source) and subsequent carbon capture and sequestration has also been proposed in the intergovernmental panel on climate change report as one of the most effective and economical strategies to remediate atmospheric greenhouse gases. To maximize photosynthetic carbon capture efficiency and energy-return-on-investment, we must develop biomass production systems that achieve the greatest yields with the lowest inputs. Numerous studies have demonstrated that microalgae have among the greatest potentials for biomass production. This is in part due to the fact that all alga cells are photoautotrophic, they have active carbon concentrating mechanisms to increase photosynthetic productivity, and all the biomass is harvestable unlike plants. All photosynthetic organisms, however, convert only a fraction of the solar energy they capture into chemical energy (reduced carbon or biomass). To increase aerial carbon capture rates and biomass productivity, it will be necessary to identify the most robust algal strains and increase their biomass production efficiency often by genetic manipulation. We review recent large-scale efforts to identify the best biomass producing strains and metabolic engineering strategies to improve aerial productivity. In addition, these strategies include optimization of photosynthetic light-harvesting antenna size to increase energy capture and conversion efficiency and the potential development of advanced molecular breeding techniques. To date, these strategies have resulted in up to twofold increases in biomass productivity.

  1. Copepod Trajectory Characteristics in Thin Layers of Toxic Algal Exudates

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; True, A. C.; Weissburg, M. J.; Yen, J.

    2013-11-01

    Recently documented thin layers of toxic phytoplankton (``cryptic blooms'') are modeled in a custom flume system for copepod behavioral assays. Planar laser-induced fluorescence (LIF) measurements quantify the spatiotemporal structure of the chemical layers ensuring a close match to in situ bloom conditions and allowing for quantification of threshold dissolved toxin levels that induce behavioral responses. Assays with the copepods Acartia tonsa (hop-sinker) and Temora longicornis (cruiser) in thin layers of toxic exudates from the common dinoflagellate Karenia brevis (cell equivalent ~ 1 - 10,000 cells/mL) examine the effects of dissolved toxic compounds and copepod species on swimming trajectory characteristics. Computation of parameters such as swimming speed and the fractal dimension of the two-dimensional trajectory (F2D) allows for statistical evaluation of copepod behavioral responses to dissolved toxic compounds associated with harmful algal blooms (HABs). Changes in copepod swimming behavior caused by toxic compounds can significantly influence predator, prey, and mate encounter rates by altering the fracticality (``diffuseness'' or ``volume-fillingness'') of a copepod's trajectory. As trophic mediators linking primary producers and higher trophic levels, copepods can significantly influence HAB dynamics and modulate large scale ecological effects through their behavioral interactions with toxic blooms.

  2. The role of selective predation in harmful algal blooms

    NASA Astrophysics Data System (ADS)

    Solé, Jordi; Garcia-Ladona, Emilio; Estrada, Marta

    2006-08-01

    A feature of marine plankton communities is the occurrence of rapid population explosions. When the blooming species are directly or indirectly noxious for humans, these proliferations are denoted as harmful algal blooms (HAB). The importance of biological interactions for the appearance of HABs, in particular when the proliferating microalgae produce toxins that affect other organisms in the food web, remains still poorly understood. Here we analyse the role of toxins produced by a microalgal species and affecting its predators, in determining the success of that species as a bloom former. A three-species predator-prey model is used to define a criterion that determines whether a toxic microalga will be able to initiate a bloom in competition against a non-toxic one with higher growth rate. Dominance of the toxic species depends on a critical parameter that defines the degree of feeding selectivity by grazers. The criterion is applied to a particular simplified model and to numerical simulations of a full marine ecosystem model. The results suggest that the release of toxic compounds affecting predators may be a plausible biological factor in allowing the development of HABs.

  3. Algal-bacterial treatment facility removes selenium from drainage water

    SciTech Connect

    Quinn, Nigel W.T.; Lundquist, Tryg J.; Green, F. Bailey; Zarate, Max A.; Oswald, William J.; Leighton, Terrance

    2000-01-25

    A demonstration algal-bacterial selenium removal (ABSR) facility has been treating agricultural drainage water in the Panoche Drainage District on the west side of the San Joaquin Valley since 1997. The project goals are to demonstrate the effectiveness of the ABSR technology for selenium removal, to investigate potential wildlife exposure to selenium at full-scale facilities, and to develop an operational plant configuration that will minimize the life-cycle cost for each pound of selenium removed. The facility consists of a series of ponds designed to promote native microorganisms that remove nitrate and selenium. Previous treatment research efforts sought to reduce selenium concentrations to less than 5 mu g/L, but the ABSR Facility demonstration focuses on providing affordable reduction of the selenium load that is discharged to the San Joaquin River. During 1997 and 1998, the best-performing ABSR plant configuration reduced nitrate by more than 95 percent and reduced total soluble selenium mass by 80 percent. Ongoing investigations focus on optimizing operational parameters and determining operational costs and scale-up engineering requirements. The preliminary total cost estimate for a 10-acre-foot per day ABSR facility is less than $200 per acre-foot of treated drainage water.

  4. Isolation of AHL-degrading bacteria from micro-algal cultures and their impact on algal growth and on virulence of Vibrio campbellii to prawn larvae.

    PubMed

    Pande, Gde Sasmita Julyantoro; Natrah, Fatin Mohd Ikhsan; Flandez, Ace Vincent Bravo; Kumar, Uday; Niu, Yufeng; Bossier, Peter; Defoirdt, Tom

    2015-12-01

    Inactivation of quorum sensing (QS) signal molecules, such as acylhomoserine lactones (AHLs) of pathogenic bacteria, has been proposed as a novel method to combat bacterial diseases in aquaculture. Despite the importance of micro-algae for aquaculture, AHL degradation by bacteria associated with micro-algal cultures has thus far not been investigated. In this study, we isolated Pseudomonas sp. NFMI-T and Bacillus sp. NFMI-C from open cultures of the micro-algae Tetraselmis suecica and Chaetoceros muelleri, respectively. An AHL degradation assay showed that either monocultures or co-cultures of the isolates were able to degrade the AHL N-hexanoyl-L-homoserine lactone. In contrast, only Bacillus sp. NFMI-C was able to inactivate N-hydroxybutanoyl-L-homoserine lactone, the AHL produced by Vibrio campbellii. The isolated bacteria were able to persist for up to 3 weeks in conventionalized micro-algal cultures, indicating that they were able to establish and maintain themselves within open algal cultures. Using gnotobiotic algal cultures, we found that the isolates did not affect growth of the micro-algae from which they were isolated, whereas a mixture of both isolates increased the growth of Tetraselmis and decreased the growth of Chaetoceros. Finally, addition of Bacillus sp. NFMI-C to the rearing water of giant river prawn (Macrobrachium rosenbergii) larvae significantly improved survival of the larvae when challenged with pathogenic V. campbellii, whereas it had no effect on larval growth. PMID:26344339

  5. Mollusc-Algal Chloroplast Endosymbiosis. Photosynthesis, Thylakoid Protein Maintenance, and Chloroplast Gene Expression Continue for Many Months in the Absence of the Algal Nucleus1

    PubMed Central

    Green, Brian J.; Li, Wei-Ye; Manhart, James R.; Fox, Theodore C.; Summer, Elizabeth J.; Kennedy, Robert A.; Pierce, Sidney K.; Rumpho, Mary E.

    2000-01-01

    Early in its life cycle, the marine mollusc Elysia chlorotica Gould forms an intracellular endosymbiotic association with chloroplasts of the chromophytic alga Vaucheria litorea C. Agardh. As a result, the dark green sea slug can be sustained in culture solely by photoautotrophic CO2 fixation for at least 9 months if provided with only light and a source of CO2. Here we demonstrate that the sea slug symbiont chloroplasts maintain photosynthetic oxygen evolution and electron transport activity through photosystems I and II for several months in the absence of any external algal food supply. This activity is correlated to the maintenance of functional levels of chloroplast-encoded photosystem proteins, due in part at least to de novo protein synthesis of chloroplast proteins in the sea slug. Levels of at least one putative algal nuclear encoded protein, a light-harvesting complex protein homolog, were also maintained throughout the 9-month culture period. The chloroplast genome of V. litorea was found to be 119.1 kb, similar to that of other chromophytic algae. Southern analysis and polymerase chain reaction did not detect an algal nuclear genome in the slug, in agreement with earlier microscopic observations. Therefore, the maintenance of photosynthetic activity in the captured chloroplasts is regulated solely by the algal chloroplast and animal nuclear genomes. PMID:10982447

  6. Algal Accessory Pigment Detection Using AVIRIS Image-Derived Spectral Radiance Data

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Ambrosia, Vincent G.

    1996-01-01

    Visual and derivative analyses of AVIRIS spectral data can be used to detect algal accessory pigments in aquatic communities. This capability extends the use of remote sensing for the study of aquatic ecosystems by allowing detection of taxonomically significant pigment signatures which yield information about the type of algae present. Such information allows remote sensing-based assessment of aquatic ecosystem health, as in the detection of nuisance blooms of cyanobacteria or toxic blooms of dinoflagellates. Remote sensing of aquatic systems has traditionally focused on quantification of chlorophyll a, a photoreactive (and light-harvesting) pigment which is common to all algae as well as cyanobacteria (bluegreen algae). Due to the ubiquitousness of this pigment within algae, chl a is routinely measured to estimate algal biomass both during ground-truthing and using various airborne or satellite based sensors, including AVIRIS. Within the remote sensing and aquatic sciences communities, ongoing research has been performed to detect algal accessory pigments for assessment of algal population composition. This research is based on the fact that many algal accessory pigments are taxonomically significant, and all are spectrally unique. Aquatic scientists have been refining pigment analysis techniques, primarily high performance liquid chromatography, or HPLC, to detect specific pigments as a time-saving alternative to individual algal cell identifications and counts. Remote sensing scientists are investigating the use of pigment signatures to construct pigment libraries analogous to mineral spectral libraries used in geological remote sensing applications. The accessory pigment approach has been used successfully in remote sensing using data from the Thematic Mapper, low-altitude, multiple channel scanners, field spectroradiometers and the AVIRIS hyperspectral scanner. Due to spectral and spatial resolution capabilities, AVIRIS is the sensor of choice for such

  7. Is the frequency of algal blooms increasing in oligotrophic lakes in temperate forests?

    NASA Astrophysics Data System (ADS)

    Paltsev, A.; Creed, I. F.

    2014-12-01

    Oligotrophic lakes in the temperate forests of eastern North America appear to be experiencing an increase in the frequency and duration of algal blooms. This has been the focus of numerous public and government reports, resulting in heightened public concern for reporting of algal blooms. There is a vital need for detailed historical survey of numerous lakes, covering large spatial scales (the scale of region, province, or entire country) and temporal scales (decades) to determine if public observations are accurate. We used a remote sensing approach to: (1) develop regression models that relate Landsat imagery reflectance to chlorophyll-a (Chl-a) as a proxy of algal biomass of lakes; (2) apply these models to estimate Chl-a in lakes at the northern edge of the temperate forest biome in central Ontario over a 28 year period (1984-2011). The linear regression model was built on the basis of the normalized exoatmospheric reflectance values acquired from the utility of Landsat TM and ETM imagery and in situ measurements. Landsat band 3 (red) showed the strongest correlation with in situ data explaining 84% of the variance in Chl-a (r2 = 0.84, p <0.001). We applied this model to all lakes within the region selected from atmospherically corrected Landsat data for the peak algal bloom period (late July to early November) for the entire 28 years. A time series revealed a cyclic stationary pattern in the average Chl-a. This pattern followed the regional patterns of major droughts, especially for the first part of the time period, making climate a major driver in the formation of algal biomass in lakes that, in turn, can lead to the rise of algal blooms. However this climate driver appeared to become less predictable, with elevated algal biomass occurring in both normal and drought years, later in the record.

  8. Arctic spring awakening - Steering principles behind the phenology of vernal ice algal blooms

    NASA Astrophysics Data System (ADS)

    Leu, E.; Mundy, C. J.; Assmy, P.; Campbell, K.; Gabrielsen, T. M.; Gosselin, M.; Juul-Pedersen, T.; Gradinger, R.

    2015-12-01

    Marine ecosystems at high latitudes are characterized by extreme seasonal changes in light conditions, as well as a limited period of high primary production during spring and early summer. As light returns at the end of winter to Arctic ice-covered seas, a first algal bloom takes place in the bottom layer of the sea ice. This bottom ice algae community develops through three distinct phases in the transition from winter to spring, starting with phase I, a predominantly net heterotroph community that has limited interaction with the pelagic or benthic realms. Phase II begins in the spring once light for photosynthesis becomes available at the ice bottom, although interaction with the water column and benthos remains limited. The transition to the final phase III is then mainly driven by a balance of atmospheric and oceanographic forcing that induce structural changes in the sea ice and ultimately the removal of algal biomass from the ice. Due to limited data availability an incomplete understanding exists of all the processes determining ice algal bloom phenology and the considerable geographic differences in sympagic algal standing stocks and primary production. We present here the first pan-Arctic compilation of available time-series data on vernal sea ice algal bloom development and identify the most important factors controlling its development and termination. Using data from the area surrounding Resolute Bay (Nunavut, Canada) as an example, we support previous investigations that snow cover on top of the ice influences sea ice algal phenology, with highest biomass development, but also earliest termination of blooms, under low snow cover. We also provide a pan-Arctic overview of sea ice algae standing stocks and primary production, and discuss the pertinent processes behind the geographic differences we observed. Finally, we assess potential future changes in vernal algal bloom phenology as a consequence of climate change, including their importance to

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

    USGS Publications Warehouse

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

    2005-01-01

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

  10. Integrative Indicator for Assessing the Alert Levels of Algal Bloom in Lakes: Lake Taihu as a Case Study

    NASA Astrophysics Data System (ADS)

    Li, Qinqin; Hu, Weiping; Zhai, Shuhua

    2016-01-01

    Algal blooms have recently become one of the most serious environmental problems in eutrophic freshwater ecosystems worldwide. Although many observation and simulation approaches have been applied to predict algal blooms, few studies have addressed the alert levels of algal blooms using integrative indicators in a large lake with multiple service function and significant horizontal heterogeneity. This study developed an integrative indicator assessment system (IIAS) to rank the alert level of algal blooms. In the IIAS, algal biomass, area percentage, distance from drinking water intake points, distance from scenic zones and duration of algal bloom were used as indicators to calculate a comprehensive alert level, which was classified into five grades (Vigilance, Low, Moderate, High, and Severe). Lake Taihu was taken as a case study to assess the comprehensive alert level of algal blooms in 2007 and 2010. The comprehensive alert level showed obvious spatial-temporal patterns, with an acceptable accuracy in Lake Taihu. The comprehensive alert levels were relatively higher in typical phytoplankton subzones than typical hydrophytes subzones and are more sensitive to weight factor in the northern and western subzones where high biomass usually occurs. Case study showed a very good application of the proposed comprehensive alert level assessment methodology, which can be adjusted to predict the degree of hazard of algal blooms in multi-service function large lakes to help the government and decision makers to act to prevent the disaster from algal bloom spreading.

  11. Integrative Indicator for Assessing the Alert Levels of Algal Bloom in Lakes: Lake Taihu as a Case Study.

    PubMed

    Li, Qinqin; Hu, Weiping; Zhai, Shuhua

    2016-01-01

    Algal blooms have recently become one of the most serious environmental problems in eutrophic freshwater ecosystems worldwide. Although many observation and simulation approaches have been applied to predict algal blooms, few studies have addressed the alert levels of algal blooms using integrative indicators in a large lake with multiple service function and significant horizontal heterogeneity. This study developed an integrative indicator assessment system (IIAS) to rank the alert level of algal blooms. In the IIAS, algal biomass, area percentage, distance from drinking water intake points, distance from scenic zones and duration of algal bloom were used as indicators to calculate a comprehensive alert level, which was classified into five grades (Vigilance, Low, Moderate, High, and Severe). Lake Taihu was taken as a case study to assess the comprehensive alert level of algal blooms in 2007 and 2010. The comprehensive alert level showed obvious spatial-temporal patterns, with an acceptable accuracy in Lake Taihu. The comprehensive alert levels were relatively higher in typical phytoplankton subzones than typical hydrophytes subzones and are more sensitive to weight factor in the northern and western subzones where high biomass usually occurs. Case study showed a very good application of the proposed comprehensive alert level assessment methodology, which can be adjusted to predict the degree of hazard of algal blooms in multi-service function large lakes to help the government and decision makers to act to prevent the disaster from algal bloom spreading. PMID:26296739

  12. Skill assessment for an operational algal bloom forecast system

    PubMed Central

    Stumpf, Richard P.; Tomlinson, Michelle C.; Calkins, Julie A.; Kirkpatrick, Barbara; Fisher, Kathleen; Nierenberg, Kate; Currier, Robert; Wynne, Timothy T.

    2010-01-01

    An operational forecast system for harmful algal blooms (HABs) in southwest Florida is analyzed for forecasting skill. The HABs, caused by the toxic dinoflagellate, Karenia brevis, lead to shellfish toxicity and to respiratory irritation. In addition to predicting new blooms and their extent, HAB forecasts are made twice weekly during a bloom event, using a combination of satellite derived image products, wind predictions, and a rule-based model derived from previous observations and research. These forecasts include: identification, intensification, transport, extent, and impact; the latter being the most significant to the public. Identification involves identifying new blooms as HABs and is validated against an operational monitoring program involving water sampling. Intensification forecasts, which are much less frequently made, can only be evaluated with satellite data on mono-specific blooms. Extent and transport forecasts of HABs are also evaluated against the water samples. Due to the resolution of the forecasts and available validation data, skill cannot be resolved at scales finer than 30 km. Initially, respiratory irritation forecasts were analyzed using anecdotal information, the only available data, which had a bias toward major respiratory events leading to a forecast accuracy exceeding 90%. When a systematic program of twice-daily observations from lifeguards was implemented, the forecast could be meaningfully assessed. The results show that the forecasts identify the occurrence of respiratory events at all lifeguard beaches 70% of the time. However, a high rate (80%) of false positive forecasts occurred at any given beach. As the forecasts were made at half to whole county level, the resolution of the validation data was reduced to county level, reducing false positives to 22% (accuracy of 78%). The study indicates the importance of systematic sampling, even when using qualitative descriptors, the use of validation resolution to evaluate forecast

  13. Unfolding the secrets of coral–algal symbiosis

    PubMed Central

    Rosic, Nedeljka; Ling, Edmund Yew Siang; Chan, Chon-Kit Kenneth; Lee, Hong Ching; Kaniewska, Paulina; Edwards, David; Dove, Sophie; Hoegh-Guldberg, Ove

    2015-01-01

    Dinoflagellates from the genus Symbiodinium form a mutualistic symbiotic relationship with reef-building corals. Here we applied massively parallel Illumina sequencing to assess genetic similarity and diversity among four phylogenetically diverse dinoflagellate clades (A, B, C and D) that are commonly associated with corals. We obtained more than 30 000 predicted genes for each Symbiodinium clade, with a majority of the aligned transcripts corresponding to sequence data sets of symbiotic dinoflagellates and <2% of sequences having bacterial or other foreign origin. We report 1053 genes, orthologous among four Symbiodinium clades, that share a high level of sequence identity to known proteins from the SwissProt (SP) database. Approximately 80% of the transcripts aligning to the 1053 SP genes were unique to Symbiodinium species and did not align to other dinoflagellates and unrelated eukaryotic transcriptomes/genomes. Six pathways were common to all four Symbiodinium clades including the phosphatidylinositol signaling system and inositol phosphate metabolism pathways. The list of Symbiodinium transcripts common to all four clades included conserved genes such as heat shock proteins (Hsp70 and Hsp90), calmodulin, actin and tubulin, several ribosomal, photosynthetic and cytochrome genes and chloroplast-based heme-containing cytochrome P450, involved in the biosynthesis of xanthophylls. Antioxidant genes, which are important in stress responses, were also preserved, as were a number of calcium-dependent and calcium/calmodulin-dependent protein kinases that may play a role in the establishment of symbiosis. Our findings disclose new knowledge about the genetic uniqueness of symbiotic dinoflagellates and provide a list of homologous genes important for the foundation of coral–algal symbiosis. PMID:25343511

  14. Multigene phylogeny of the red algal subclass Nemaliophycidae.

    PubMed

    Lam, Daryl W; Verbruggen, Heroen; Saunders, Gary W; Vis, Morgan L

    2016-01-01

    The red algae (Rhodophyta) are a lineage of primary endosymbionts whose ancestors represent some of the first photosynthetic eukaryotes on the planet. They primarily inhabit marine ecosystems, with only ∼5% of species found in freshwater systems. The subclass Nemaliophycidae is very diverse in ecological and life history features and therefore a useful model to study these traits, but the phylogenetic relationships among the orders are, for the most part, poorly resolved. To elucidate the phylogeny of the Nemaliophycidae, we constructed a nine-gene dataset comprised of nuclear, plastid, and mitochondrial markers for 67 red algal specimens. The resulting maximum likelihood (ML) phylogeny confirmed the monophyly of all orders. The sister relationship of the Acrochaetiales and Palmariales received high support and the relationship of the Balliales with Balbianiales and Entwisleiales with Colaconematales was moderately supported. The Nemaliales, Entwisleiales, Colaconematales, Palmariales and Acrochaetiales formed a highly supported clade. Unfortunately, all other relationships among the orders had low bootstrap support. Although the ML analysis did not resolve many of the relationships, further analyses suggested that a resolution is possible. A Phycas analysis supported a dichotomously branching tree and Bayesian analysis showed a similar topology with all relationships highly supported. Simulations extrapolating the number of nucleotide characters beyond the current size of the dataset suggested that most nodes in the phylogeny would be resolved if more data become available. Phylogenomic approaches will be necessary to provide a well-supported phylogeny of this subclass with all relationships resolved such that the evolution of freshwater species from marine ancestors as well as reproductive traits can be explored. PMID:26518739

  15. Unfolding the secrets of coral-algal symbiosis.

    PubMed

    Rosic, Nedeljka; Ling, Edmund Yew Siang; Chan, Chon-Kit Kenneth; Lee, Hong Ching; Kaniewska, Paulina; Edwards, David; Dove, Sophie; Hoegh-Guldberg, Ove

    2015-04-01

    Dinoflagellates from the genus Symbiodinium form a mutualistic symbiotic relationship with reef-building corals. Here we applied massively parallel Illumina sequencing to assess genetic similarity and diversity among four phylogenetically diverse dinoflagellate clades (A, B, C and D) that are commonly associated with corals. We obtained more than 30,000 predicted genes for each Symbiodinium clade, with a majority of the aligned transcripts corresponding to sequence data sets of symbiotic dinoflagellates and <2% of sequences having bacterial or other foreign origin. We report 1053 genes, orthologous among four Symbiodinium clades, that share a high level of sequence identity to known proteins from the SwissProt (SP) database. Approximately 80% of the transcripts aligning to the 1053 SP genes were unique to Symbiodinium species and did not align to other dinoflagellates and unrelated eukaryotic transcriptomes/genomes. Six pathways were common to all four Symbiodinium clades including the phosphatidylinositol signaling system and inositol phosphate metabolism pathways. The list of Symbiodinium transcripts common to all four clades included conserved genes such as heat shock proteins (Hsp70 and Hsp90), calmodulin, actin and tubulin, several ribosomal, photosynthetic and cytochrome genes and chloroplast-based heme-containing cytochrome P450, involved in the biosynthesis of xanthophylls. Antioxidant genes, which are important in stress responses, were also preserved, as were a number of calcium-dependent and calcium/calmodulin-dependent protein kinases that may play a role in the establishment of symbiosis. Our findings disclose new knowledge about the genetic uniqueness of symbiotic dinoflagellates and provide a list of homologous genes important for the foundation of coral-algal symbiosis. PMID:25343511

  16. Modeling of polymer brush grafted nanoparticles for algal harvesting

    NASA Astrophysics Data System (ADS)

    Goins, Jason

    Microalgae derived biofuel shows great potential as a replacement to petroleum based fuels. However, industrial scale and economical production of fuel from microalgae suffer from an expensive dewatering step brought on by the organism's specific cell properties. A retrievable, paramagnetic nanoparticle polyelectrolyte brush (NPPB) has been designed as a flocculation agent to provide a low cost method in collecting algal biomass in biofuel production. In conjunction with experiment, subsequent theoretical investigations have been conducted in order to understand experimental observations and inform future design. A strategy has been implemented to provide informative descriptions for the relationship between flocculation agent parameters and dewatering efficiency. We studied the effect altering the degree of polymerization and monomer charge fraction had on the harvesting efficiency by considering flocculation as the criteria for harvesting. As the number of charges on the polymer backbone of the NPPB is increased, less NPPB concentrations are required to achieve equal harvesting efficiencies. This is a result of needing less NPPB to completely screen the effective charge on the algae surface. However, the Debye length limits the amount of charge on the algae surface one NPPB can screen. Using the free energy calculations for the complete set of pair interactions between the NPPB and the algae, we determined how many adsorbed NPPB were required in order for the force between coated algae to become attractive at some algae surface separation. This corresponded to the NPPB bridging two algae surfaces. NPPB with higher monomer charge fractions and degree of polymerizations led to a stronger bridging bond and larger bridging gap that could outweigh the algae pair repulsion. Optimized structures maximize these effects.

  17. Bifunctional aldehyde/alcohol dehydrogenase (ADHE) in chlorophyte algal mitochondria.

    PubMed

    Atteia, Ariane; van Lis, Robert; Mendoza-Hernández, Guillermo; Henze, Katrin; Martin, William; Riveros-Rosas, Hector; González-Halphen, Diego

    2003-09-01

    Protein profiles of mitochondria isolated from the heterotrophic chlorophyte Polytomella sp. grown on ethanol at pH 6.0 and pH 3.7 were analyzed by Blue Native and denaturing polyacrylamide gel electrophoresis. Steady-state levels of oxidative phosphorylation complexes were influenced by external pH. Levels of an abundant, soluble, mitochondrial protein of 85 kDa and its corresponding mRNA increased at pH 6.0 relative to pH 3.7. N-terminal and internal sequencing of the 85 kDa mitochondrial protein together with the corresponding cDNA identified it as a bifunctional aldehyde/alcohol dehydrogenase (ADHE) with strong similarity to homologues from eubacteria and amitochondriate protists. A mitochondrial targeting sequence of 27 amino acids precedes the N-terminus of the mature mitochondrial protein. A gene encoding an ADHE homologue was also identified in the genome of Chlamydomonas reinhardtii, a photosynthetic relative of Polytomella. ADHE reveals a complex picture of sequence similarity among homologues. The lack of ADHE from archaebacteria indicates a eubacterial origin for the eukaryotic enzyme. Among eukaryotes, ADHE has hitherto been characteristic of anaerobes since it is essential to cytosolic energy metabolism of amitochondriate protists such as Giardia intestinalis and Entamoeba histolytica. Its abundance and expression pattern suggest an important role for ADHE in mitochondrial metabolism of Polytomella under the conditions studied. The current data are compatible with the view that Polytomella ADHE could be involved either in ethanol production or assimilation, or both, depending upon environmental conditions. Presence of ADHE in an oxygen-respiring algal mitochondrion and co-expression at ambient oxygen levels with respiratory chain components is unexpected with respect to the view that eukaryotes acquired ADHE genes specifically as an adaptation to an anaerobic lifestyle. PMID:14756315

  18. Strategies for optimizing algal biology for enhanced biomass production

    DOE PAGESBeta

    Barry, Amanda N.; Starkenburg, Shawn R.; Sayre, Richard T.

    2015-02-02

    One of the most environmentally sustainable ways to produce high-energy density (oils) feed stocks for the production of liquid transportation fuels is from biomass. Photosynthetic carbon capture combined with biomass combustion (point source) and subsequent carbon capture and sequestration has also been proposed in the intergovernmental panel on climate change report as one of the most effective and economical strategies to remediate atmospheric greenhouse gases. To maximize photosynthetic carbon capture efficiency and energy-return-on-investment, we must develop biomass production systems that achieve the greatest yields with the lowest inputs. Numerous studies have demonstrated that microalgae have among the greatest potentials formore » biomass production. This is in part due to the fact that all alga cells are photoautotrophic, they have active carbon concentrating mechanisms to increase photosynthetic productivity, and all the biomass is harvestable unlike plants. All photosynthetic organisms, however, convert only a fraction of the solar energy they capture into chemical energy (reduced carbon or biomass). To increase aerial carbon capture rates and biomass productivity, it will be necessary to identify the most robust algal strains and increase their biomass production efficiency often by genetic manipulation. We review recent large-scale efforts to identify the best biomass producing strains and metabolic engineering strategies to improve aerial productivity. In addition, these strategies include optimization of photosynthetic light-harvesting antenna size to increase energy capture and conversion efficiency and the potential development of advanced molecular breeding techniques. To date, these strategies have resulted in up to twofold increases in biomass productivity.« less

  19. An Application of Lagrangian Coherent Structures to Harmful Algal Blooms

    NASA Astrophysics Data System (ADS)

    Olascoaga, M. J.; Beron-Vera, F. J.; Brand, L. E.; Kocak, H.

    2009-04-01

    Karenia brevis is present in low concentrations in vast areas of the Gulf of Mexico (GoM). This toxic dinoflagellate sporadically develops blooms anywhere in the GoM, except in the southern portion of West Florida Shelf (WFS). There, these harmful algal blooms (HABs) are recurrent events whose frequency and intensity are increasing. HABs on the WFS are usually only evident once they have achieved high concentrations that can be detected by observation of discolored water, which may be apparent in satellite imagery; by ecological problems such as fish kills; or human health problems. Because the early development stages of HABs are usually not detected, there is limited understanding of the environmental conditions that lead to their development. Analysis of simulated surface ocean currents reveals the presence of a persistent large-scale Lagrangian coherent structure (LCS) on the southern portion of the WFS. A LCS can be regarded as a distinguished material line which divides immiscible fluid regions with distinct advection properties. Consistent with satellite-tracked drifter trajectories, this LCS on the WFS constitutes a cross-shelf barrier for the lateral transport of passive tracers. We hypothesize that such a LCS provides favorable conditions for the development of HABs. LCSs are also employed to trace the early location of an observed HAB on the WFS. Using a simplified population dynamics model we infer the factors that could possibly lead to the development of this HAB. The population dynamics model determines nitrogen in two components, nutrients and phytoplankton, which are assumed to be passively advected by simulated surface ocean currents. Two nutrient sources are inferred for the HAB whose evolution is found to be strongly tied to the simulated LCSs. These nutrient sources are found to be located near shore and likely due to land runoff.

  20. Skill assessment for an operational algal bloom forecast system

    NASA Astrophysics Data System (ADS)

    Stumpf, Richard P.; Tomlinson, Michelle C.; Calkins, Julie A.; Kirkpatrick, Barbara; Fisher, Kathleen; Nierenberg, Kate; Currier, Robert; Wynne, Timothy T.

    2009-02-01

    An operational forecast system for harmful algal blooms (HABs) in southwest Florida is analyzed for forecasting skill. The HABs, caused by the toxic dinoflagellate, Karenia brevis, lead to shellfish toxicity and to respiratory irritation. In addition to predicting new blooms and their extent, HAB forecasts are made twice weekly during a bloom event, using a combination of satellite derived image products, wind predictions, and a rule-based model derived from previous observations and research. These forecasts include: identification, intensification, transport, extent, and impact; the latter being the most significant to the public. Identification involves identifying new blooms as HABs and is validated against an operational monitoring program involving water sampling. Intensification forecasts, which are much less frequently made, can only be evaluated with satellite data on mono-specific blooms. Extent and transport forecasts of HABs are also evaluated against the water samples. Due to the resolution of the forecasts and available validation data, skill cannot be resolved at scales finer than 30 km. Initially, respiratory irritation forecasts were analyzed using anecdotal information, the only available data, which had a bias toward major respiratory events leading to a forecast accuracy exceeding 90%. When a systematic program of twice-daily observations from lifeguards was implemented, the forecast could be meaningfully assessed. The results show that the forecasts identify the occurrence of respiratory events at all lifeguard beaches 70% of the time. However, a high rate (80%) of false positive forecasts occurred at any given beach. As the forecasts were made at half to whole county level, the resolution of the validation data was reduced to county level, reducing false positives to 22% (accuracy of 78%). The study indicates the importance of systematic sampling, even when using qualitative descriptors, the use of validation resolution to evaluate forecast

  1. Algal conditions in the Caloosahatchee River (1975-79), Lake Okeechobee to Franklin Lock, Florida

    USGS Publications Warehouse

    McPherson, Benjamin F.; La Rose, Henry R.

    1982-01-01

    Maximum numbers of suspended algae occurred in late spring and early summer, in each of the years 1975-79, in the Caloosahatchee River. Numbers exceeded 100,000 cells per milliliter at all stations sometime during the study. Concentrations decreased during late summer and autumn and were low during winter, except in January 1979 when numbers at most sites exceeded 100,000 cells per milliliter. The January 1979 bloom coincided with large discharges from Lake Okeechobee. During previous winters, discharges and algal numbers were lower. During other seasons, algal blooms occurred most frequently under low-flow or stagnant conditions. The upstream site at Moore Haven, which had the least discharge and was most stagnant, had consistently higher algal concentrations than downstream sites. Blue-green algae were dominant in the river during the summer at the upstream site throughout the year. The percentage of blue-green algae decreased downstream. Concentrations of nitrite plus nitrate nitrogen were inversely correlated with concentrations of algae and decreased to near zero during algal blooms. The low concentrations of these forms of inorganic nitrogen relative to other major nutrients probably favor blue-green algae and limit growth of other algae. Contributions by the basin tributaries to the nutritive condition of the river were small because concentrations of nutrients, algal growth potential, and algae in the tributaries were generally less than those in the river. (USGS)

  2. Algal bioassessment metrics for wadeable streams and rivers of Maine, USA

    USGS Publications Warehouse

    Danielson, T.J.; Loftin, C.S.; Tsomides, L.; Difranco, J.L.; Connors, B.

    2011-01-01

    Many state water-quality agencies use biological assessment methods based on lotic fish and macroinvertebrate communities, but relatively few states have incorporated algal multimetric indices into monitoring programs. Algae are good indicators for monitoring water quality because they are sensitive to many environmental stressors. We evaluated benthic algal community attributes along a landuse gradient affecting wadeable streams and rivers in Maine, USA, to identify potential bioassessment metrics. We collected epilithic algal samples from 193 locations across the state. We computed weighted-average optima for common taxa for total P, total N, specific conductance, % impervious cover, and % developed watershed, which included all land use that is no longer forest or wetland. We assigned Maine stream tolerance values and categories (sensitive, intermediate, tolerant) to taxa based on their optima and responses to watershed disturbance. We evaluated performance of algal community metrics used in multimetric indices from other regions and novel metrics based on Maine data. Metrics specific to Maine data, such as the relative richness of species characterized as being sensitive in Maine, were more correlated with % developed watershed than most metrics used in other regions. Few community-structure attributes (e.g., species richness) were useful metrics in Maine. Performance of algal bioassessment models would be improved if metrics were evaluated with attributes of local data before inclusion in multimetric indices or statistical models. ?? 2011 by The North American Benthological Society.

  3. Problems related to water quality and algal control in Lopez Reservoir, San Luis Obispo County, California

    USGS Publications Warehouse

    Fuller, Richard H.; Averett, Robert C.; Hines, Walter G.

    1975-01-01

    A study to determine the present enrichment status of Liopez Reservoir in San Luis Obispo county, California, and to evaluate copper sulfate algal treatment found that stratification in the reservoir regulates nutrient release and that algal control has been ineffective. Nuisance algal blooms, particularly from March to June, have been a problem in the warm multipurpose reservoir since it was initially filled following intense storms in 1968-69. The cyanophyte Anabaena unispora has been dominant; cospecies are the diatoms Stephanodiscus astraea and Cyclotella operculata, and the chlorophytes Pediastrum deplex and Sphaerocystis schroeteri. During an A. unispora bloom in May 1972 the total lake surface cell count was nearly 100,000 cells/ml. Thermal stratification from late spring through autumn results in oxygen deficiency in the hypolimnion and metalimnion caused by bacterial oxidation of organic detritus. The anaerobic conditions favor chemical reduction of organic matter, which constitute 10-14% of the sediment. As algae die, sink to the bottom, and decompose, nutrients are released to the hypolimnion , and with the autumn overturn are spread to the epilimnion. Algal blooms not only hamper recreation, but through depletion of dissolved oxygen in the epilimnion may have caused periodic fishkills. Copper sulfate mixed with sodium citrate and applied at 1.10-1.73 lbs/acre has not significantly reduced algal growth; a method for determining correct dosage is presented. (Lynch-Wisconsin)

  4. Harmful Algal Bloom Hotspots Really Are Hot: A Case Study from Monterey Bay, California

    NASA Astrophysics Data System (ADS)

    Kudela, R. M.; Anderson, C.; Birch, J. M.; Bowers, H.; Caron, D. A.; Chao, Y.; Doucette, G.; Farrara, J. D.; Gellene, A. G.; Negrey, K.; Howard, M. D.; Ryan, J. P.; Scholin, C. A.; Smith, J.; Sukhatme, G.

    2015-12-01

    Monterey Bay, California is one of several recognized hotspots for harmful algal blooms along the US west coast, particularly for the toxigenic diatom Pseudo-nitzschia, which produces domoic acid and is responsible for Amnesic Shellfish Poisoning. Historical observations have linked bloom activity to anomalously warm conditions with weak and sporadic upwelling. In particular, blooms appear to be associated with El Niño conditions. Monterey, as with much of the US west coast, experienced unusual warm conditions in spring and summer 2014, leading to multiple ecosystem effects including massive algal blooms, concentration of apex predators nearshore, and unusually high levels of domoic acid. As the warm anomalies continued and strengthened into 2015, Monterey (and much of the west coast) has been experiencing the largest and most toxic algal bloom recorded in the last 15 years, as well as unprecedented coccolithophore blooms associated with warm, nutrient-depleted waters. With the strengthening El Niño conditions developing in summer 2015, it is possible that 2016 will result in a third consecutive year of unusually toxic algal blooms. Using a combination of historical observations, intensive field studies, and predictive models we explore the hypothesis that these warm anomalies lead to shifts in the typical upwelling-dominated food web leading to a collapse of the ecosystem towards the coast, unusual algal blooms, and enhanced trophic transfer of toxins, resulting in magnified negative impacts to wildlife and, potentially, humans.

  5. Phycoremediation coupled production of algal biomass, harvesting and anaerobic digestion: possibilities and challenges.

    PubMed

    Prajapati, Sanjeev Kumar; Kaushik, Prachi; Malik, Anushree; Vijay, Virendra Kumar

    2013-12-01

    Biogas produced from anaerobic digestion is a versatile and environment friendly fuel which traditionally utilizes cattle dung as the substrate. In the recent years, owing to its high content of biodegradable compounds, algal biomass has emerged as a potential feedstock for biogas production. Moreover, the ability of algae to treat wastewater and fix CO2 from waste gas streams makes it an environmental friendly and economically feasible feedstock. The present review focuses on the possibility of utilizing wastewater as the nutrient and waste gases as the CO2 source for algal biomass production and subsequent biogas generation. Studies describing the various harvesting methods of algal biomass as well as its anaerobic digestion have been compiled and discussed. Studies targeting the most recent advancements on biogas enrichment by algae have been discussed. Apart from highlighting the various advantages of utilizing algal biomass for biogas production, limitations of the process such as cell wall resistivity towards digestion and inhibitions caused due to ammonia toxicity and the possible strategies for overcoming the same have been reviewed. The studies compiled in the present review indicate that if the challenges posed in translating the lab scale studies on phycoremediation and biogas production to pilot scale are overcome, algal biogas could become the sustainable and economically feasible source of renewable energy. PMID:23827782

  6. Simulated Macro-Algal Outbreak Triggers a Large-Scale Response on Coral Reefs.

    PubMed

    Welsh, Justin Q; Bellwood, David R

    2015-01-01

    Ecosystem degradation has become common throughout the world. On coral reefs, macroalgal outbreaks are one of the most widely documented signs of degradation. This study simulated local-scale degradation on a healthy coral reef to determine how resident taxa, with the potential to reverse algal outbreaks, respond. We utilized a combination of acoustic and video monitoring to quantify changes in the movements and densities, respectively, of coral reef herbivores following a simulated algal outbreak. We found an unprecedented accumulation of functionally important herbivorous taxa in response to algal increases. Herbivore densities increased by 267% where algae were present. The increase in herbivore densities was driven primarily by an accumulation of the browsing taxa Naso unicornis and Kyphosus vaigiensis, two species which are known to be important in removing macroalgae and which may be capable of reversing algal outbreaks. However, resident individuals at the site of algal increase exhibited no change in their movements. Instead, analysis of the size classes of the responding individuals indicates that large functionally-important non-resident individuals changed their movement patterns to move in and feed on the algae. This suggests that local-scale reef processes may not be sufficient to mitigate the effects of local degradation and highlights the importance of mobile links and cross-scale interactions. PMID:26171788

  7. Simulated Macro-Algal Outbreak Triggers a Large-Scale Response on Coral Reefs

    PubMed Central

    Welsh, Justin Q.; Bellwood, David R.

    2015-01-01

    Ecosystem degradation has become common throughout the world. On coral reefs, macroalgal outbreaks are one of the most widely documented signs of degradation. This study simulated local-scale degradation on a healthy coral reef to determine how resident taxa, with the potential to reverse algal outbreaks, respond. We utilized a combination of acoustic and video monitoring to quantify changes in the movements and densities, respectively, of coral reef herbivores following a simulated algal outbreak. We found an unprecedented accumulation of functionally important herbivorous taxa in response to algal increases. Herbivore densities increased by 267% where algae were present. The increase in herbivore densities was driven primarily by an accumulation of the browsing taxa Naso unicornis and Kyphosus vaigiensis, two species which are known to be important in removing macroalgae and which may be capable of reversing algal outbreaks. However, resident individuals at the site of algal increase exhibited no change in their movements. Instead, analysis of the size classes of the responding individuals indicates that large functionally-important non-resident individuals changed their movement patterns to move in and feed on the algae. This suggests that local-scale reef processes may not be sufficient to mitigate the effects of local degradation and highlights the importance of mobile links and cross-scale interactions. PMID:26171788

  8. Multiple genes of apparent algal origin suggest ciliates may once have been photosynthetic.

    PubMed

    Reyes-Prieto, Adrian; Moustafa, Ahmed; Bhattacharya, Debashish

    2008-07-01

    Plantae (as defined by Cavalier-Smith, 1981) plastids evolved via primary endosymbiosis whereby a heterotrophic protist enslaved a photosynthetic cyanobacterium. This "primary" plastid spread into other eukaryotes via secondary endosymbiosis. An important but contentious theory in algal evolution is the chromalveolate hypothesis that posits chromists (cryptophytes, haptophytes, and stramenopiles) and alveolates (ciliates, apicomplexans, and dinoflagellates) share a common ancestor that contained a red-algal-derived "secondary" plastid. Under this view, the existence of several later-diverging plastid-lacking chromalveolates such as ciliates and oomycetes would be explained by plastid loss in these lineages. To test the idea of a photosynthetic ancestry for ciliates, we used the 27,446 predicted proteins from the macronuclear genome of Tetrahymena thermophila to query prokaryotic and eukaryotic genomes. We identified 16 proteins of possible algal origin in the ciliates Tetrahymena and Paramecium tetraurelia. Fourteen of these are present in other chromalveolates. Here we compare and contrast the likely scenarios for algal-gene origin in ciliates either via multiple rounds of horizontal gene transfer (HGT) from algal prey or symbionts, or through endosymbiotic gene transfer (EGT) during a putative photosynthetic phase in their evolution. PMID:18595706

  9. Atmosphere stabilization and element recycle in an experimental mouse-algal system

    NASA Technical Reports Server (NTRS)

    Smernoff, David T.

    1986-01-01

    Life support systems based on bioregeneration rely on the control and manipulation of organisms. Experiments conducted with a gas-closed mouse-algal system designed to investigate principles of photosynthetic gas exchange focus primarily on observing gas exchange phenomena under varying algal environmental conditions and secondarily on studying element cycling through compartments of the experimental system. Inherent instabilities exit between the uptake and release of carbon dioxide CO2 and oxygen O2 by the mouse and algae. Variations in light intensity and cell density alter the photosynthetic rate of the algae and enable maintenance of physiologic concentrations of CO2 and O2. Different nitrogen sources (urea and nitrate) result in different algal assimilatory quotients (AQ). Combinations of photosynthetic rate and AQ ratio manipulations have been examined for their potential in stabilizing atmospheric gas concentrations in the gas-closed algal-mouse system. Elemental mass balances through the experimental systems compartments are being studied with the concurrent development of a mathematical simulation model. Element cycling experiments include quantification of elemental flows through system compartments and wet oxidation of system waste materials for use as an algal nutrient source. Oxidized waste products demonstrate inhibitory properties although dilution has been shown to allow normal growth.

  10. Sedimentation of an upper Pennsylvanian phylloid algal mound complex, Hueco Mountains, El Paso County, TX

    SciTech Connect

    Pol, J.C.

    1984-04-01

    A Late Pennsylvanian mixed carbonate-clastic sequence is exposed in the Hueco Mountains of west Texas. The sequence begins with deposition of a progradational fan-delta system and marine and tidal-flat carbonates. This unit is dominated by calclithite and shale with minor interbeds of shallow-water calcareous mudstone and wackestone. Shallow-water spiculites are commonly associated with these limestones. A thick carbonate unit composed predominantly of limestone overlies the clastics; it was deposited during or just after a major local transgression. The carbonate sediments were deposited on the submerged delta platform in the following sequence: (1) colonization of the shallow platform by rugose corals and early (or syndepositional) cementation of the zone; (2) establishment of shallow-water dasycladacean algal flats; (3) increasing domination of the environment by phylloid algae in response to increasing water depth; (4) accretion of phylloid algal sediments and formation of mounds (directly overlying the dasycladacean algal flats are a number of small mounds formed by accelerated sedimentation within phylloids algal meadows. The high productivity of the phylloid algae and their sediment-trapping ability allowed sedimentation to keep up with sea level rise. Large bioherms resulted, but because of the difference in accretion rates of various mounds, some grew while others were buried by more successful neighbors); and (5) reestablishment of shallow-water dasycladacean algal flats as a result of shoaling of mounds crests and subsequent increase sedimentation in deeper, quieter water on the lee side of the mound complex.

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

    PubMed

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

    2014-09-01

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

  12. Geographic analysis of the feasibility of collocating algal biomass production with wastewater treatment plants.

    PubMed

    Fortier, Marie-Odile P; Sturm, Belinda S M

    2012-10-16

    Resource demand analyses indicate that algal biodiesel production would require unsustainable amounts of freshwater and fertilizer supplies. Alternatively, municipal wastewater effluent can be used, but this restricts production of algae to areas near wastewater treatment plants (WWTPs), and to date, there has been no geospatial analysis of the feasibility of collocating large algal ponds with WWTPs. The goals of this analysis were to determine the available areas by land cover type within radial extents (REs) up to 1.5 miles from WWTPs; to determine the limiting factor for algal production using wastewater; and to investigate the potential algal biomass production at urban, near-urban, and rural WWTPs in Kansas. Over 50% and 87% of the land around urban and rural WWTPs, respectively, was found to be potentially available for algal production. The analysis highlights a trade-off between urban WWTPs, which are generally land-limited but have excess wastewater effluent, and rural WWTPs, which are generally water-limited but have 96% of the total available land. Overall, commercial-scale algae production collocated with WWTPs is feasible; 29% of the Kansas liquid fuel demand could be met with implementation of ponds within 1 mile of all WWTPs and supplementation of water and nutrients when these are limited. PMID:22970803

  13. Algal control and enhanced removal in drinking waters in Cairo, Egypt.

    PubMed

    El-Dars, Farida M S E; Abdel Rahman, M A M; Salem, Olfat M A; Abdel-Aal, El-Sayed A

    2015-12-01

    Algal blooms at the major water treatment plants in Egypt have been reported since 2006. While previous studies focused on algal types and their correlation with disinfection by-products, correlation between raw water quality and algal blooms were not explored. Therefore, a survey of Nile water quality parameters at a major water intake in the Greater Cairo Urban Region was conducted from December 2011 to November 2012. Bench-scale experiments were conducted to evaluate the effectiveness of the conventional chloride/alum treatment compared with combined Cl/permanganate pre-oxidation with Al and Fe coagulants during the outbreak period. Addition of permanganate (0.5 mg/L) significantly reduced the chlorine demand from 5.5 to 2.7 mg/L. The applied alum coagulant dose was slightly reduced while residual Al was reduced by 27% and the algal count by 50% in the final treated waters. Applying ferric chloride and ferric sulfate as coagulants to waters treated with the combined pre-oxidation procedure effectively reduced algal count by 60% and better the total organic carbon reduction and residual aluminum in the treated water. Multivariate statistical analysis was used to identify the relationship between water quality parameters and occurrence of algae and to explain the impact of coagulants on the final water quality. PMID:26608768

  14. Poblacion estelar joven embebida en la nube molecular galactica asociada a la fuente IRAS 18236-1205

    NASA Astrophysics Data System (ADS)

    Romero, Ricardo Retes

    2008-06-01

    En esta tesis presento una metodología de seleccion y estudio de la población estelar embebida en la nube molecular galactica asociada a la fuente IRAS 18236-1205. La fuente IRAS posee colores de region Ultra Compacta HII (UCHII) y tiene deteccióon en monosulfuro de carbono (CS), trazador molecular de alta densidad, lo cual da la posibilidad de definir la nube molecular asociada hacia esta region. Lo anterior muestra que esta es buena candidata a región de formación estelar masiva. La metodología de seleccion de la población embebida, est à basada por una parte, en la distribución del gas molecular monoxido de carbono (13CO) asociado a la fuente IRAS, nube molecular seleccionada del mapeo Galactic Ring Survey (GRS) realizado en 13CO. Otros pasos de la seleccion, se basan en los diagramas color-color y color-magnitud con datos del cercano infrarrrojo de 2MASS. Para el estudio de la componente estelar se usaron los catalogos de fuentes puntuales en el cercano, medio y lejano infrarrojo de 2MASS, SPITZER e IRAS, respectivamente. De los diagramas color-color y color-magnitud, usando datos de 2MASS, se construyo un criterio fotométrico para identificar los objetos estelares j ovenes embebidos en la region molecular. Aplicando modelos a la distribución espectral de energía (SED) de algunos ellos, se encontraron parametros estelares de objetos estelares j ovenes embebidos de masa intermedia y alta. Adicionalmente, se encontro un objeto de masa ´ intermedia no identifiado por el catalogo de 2MASS y su efecto sobre el medio interestelar, emision en la banda de [4.5] μm de IRAC-Spitzer asociado a un outflow. Dos de los objetos seleccionados por el criterio fotometrico resultaron ser objetos estelares jovenes de alta e intermedia masa (B1V/B2V y B8V/A0V respectivamente), los cuales deben estar asociados a la emision radiativa responsable de los colores de región UC HII. Otro objeto estelar joven de baja masa (F0V/F5V) fue encontrado en la region de estudio

  15. Treatment of dairy manure effluent using freshwater algae: algal productivity and recovery of manure nutrients using pilot-scale algal turf scrubbers.

    PubMed

    Mulbry, Walter; Kondrad, Shannon; Pizarro, Carolina; Kebede-Westhead, Elizabeth

    2008-11-01

    Cultivating algae on nitrogen (N) and phosphorus (P) in animal manure effluents presents an alternative to the current practice of land application. The objective of this study was to determine values for productivity, nutrient content, and nutrient recovery using filamentous green algae grown in outdoor raceways at different loading rates of raw and anaerobically digested dairy manure effluent. Algal turf scrubber raceways (30m2 each) were operated in central Maryland for approximately 270 days each year (roughly April 1-December 31) from 2003 to 2006. Algal biomass was harvested every 4-12 days from the raceways after daily additions of manure effluent corresponding to loading rates of 0.3 to 2.5g total N (TN) and 0.08 to 0.42g total P (TP) m(-2)d(-1). Mean algal productivity values increased from approximately 2.5g DW m(-2)d(-1) at the lowest loading rate (0.3g TN m(-2)d(-1)) to 25g DW m(-2)d(-1) at the highest loading rate (2.5g TN m(-2)d(-1)). Mean N and P contents in the dried biomass increased 1.5-2.0-fold with increasing loading rate up to maximums of 7% N and 1% P (dry weight basis). Although variable, algal N and P accounted for roughly 70-90% of input N and P at loading rates below 1g TN, 0.15g TP m(-2)d(-1). N and P recovery rates decreased to 50-80% at higher loading rates. There were no significant differences in algal productivity, algal N and P content, or N and P recovery values from raceways with carbon dioxide supplementation compared to values from raceways without added carbon dioxide. Projected annual operational costs are very high on a per animal basis ($780 per cow). However, within the context of reducing nutrient inputs in sensitive watersheds such as the Chesapeake Bay, projected operational costs of $11 per kgN are well below the costs cited for upgrading existing water treatment plants. PMID:18487042

  16. From MERIS To OLCI And Sentinel 2: Harmful Algal Bloom Applications & Modelling In South Africa

    NASA Astrophysics Data System (ADS)

    Robertson Lain, L.; Bernard, S.; Evers-King, H.; Matthews, M. W.; Smith, M.

    2013-12-01

    The Sentinel 2 and 3 missions offer new capabilities for Harmful Algal Bloom (HAB) observations in Southern Africa and further afield on the African continent where there is a great need for improved monitoring of water quality: both in freshwater resources where eutrophication is common, and in vulnerable coastal ecosystems. Two well validated algorithms - Equivalent Algal Populations (EAP) & Maximum Peak Height (MPH) - available for operational use on eutrophic waters are described. Spectral remote sensing reflectances (Rrs) and inherent optical properties (IOPs) are characterised via measurement and modelling of phytoplankton assemblages typical of high biomass algal blooms of the Southern Benguela and inland waters of South Africa. Sensitivity to phytoplankton functional types (PFTs) is investigated, with focus on optically significant biological characteristics e.g. particle size distribution and intracellular structure (including vacuoles).

  17. Process for selection of Oxygen-tolerant algal mutants that produce H.sub.2

    DOEpatents

    Ghirardi, Maria L.; Seibert, Michael

    1999-01-01

    A process for selection of oxygen-tolerant, H.sub.2 -producing algal mutant cells comprising: (a) growing algal cells photoautotrophically under fluorescent light to mid log phase; (b) inducing algal cells grown photoautrophically under fluorescent light to mid log phase in step (a) anaerobically by (1) resuspending the cells in a buffer solution and making said suspension anaerobic with an inert gas; (2) incubating the suspension in the absence of light at ambient temperature; (c) treating the cells from step (b) with metronidazole, sodium azide, and added oxygen to controlled concentrations in the presence of white light. (d) washing off metronidazole and sodium azide to obtain final cell suspension; (e) plating said final cell suspension on a minimal medium and incubating in light at a temperature sufficient to enable colonies to appear; (f) counting the number of colonies to determine the percent of mutant survivors; and (g) testing survivors to identify oxygen-tolerant H.sub.2 -producing mutants.

  18. Remote sensing of ALGAL pigments to determine coastal phytoplankton dynamics in Florida Bay

    SciTech Connect

    Richardson, L.L.; Ambrosia, V.G.

    1997-06-01

    An important component of remote sensing of marine and coastal environments is the detection of phytoplankton to estimate biological activity. Traditionally the focus has been on detection of chlorophyll a, a photosynthetic pigment common to all algal groups. Recent advances in remote sensing instrumentation, in particular the development of hyperspectral imaging sensors, allow detection of additional algal pigments that include taxonomically significant photosynthetic and photoprotective accessory pigments. We are working with the hyperspectral imaging sensor AVIRIS (the Airborne Visible-Infrared Imaging Spectrometer) to characterize phytoplankton blooms in Florida Bay. Our data analysis focuses on intersection of image data (and image-derived spectral data) with our in-house library of algal pigment signatures.

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

    NASA Astrophysics Data System (ADS)

    Aponte, Nilda E.; Ballantine, David L.

    2001-10-01

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

  20. Algal layer ratios as indicators of air pollutant effects in Permelia sulcata

    USGS Publications Warehouse

    Bennett, J.P.

    2002-01-01

    Parmelia sulcata Taylor is generally believed to be fairly pollution tolerant, and consequently it is sometimes collected in urban and/or polluted localities. The condition of these specimens, however, is not always luxuriant and healthy. This study tested the hypothesis that total thallus and algal layer thickness, and the algal layer ratio would be thinner in polluted areas, thus allowing these characters to be used a indicators of air pollutant effects. Herbarium specimens were studied from 16 different localities varying in pollution level. The thallus and algal layers and ratio were not affected by year or locality of sampling, but decreased 11, 31 and 21% respectively between low and high pollution level localities. These results agreed with earlier studies using other species, but further work is needed to clarify the effects of geography and substrate on these phenomena.

  1. ERTS-1 observes algal blooms in Lake Erie and Utah Lake

    NASA Technical Reports Server (NTRS)

    Strong, A. E.

    1973-01-01

    During late summer when the surface waters of Lake Erie reach their maximum temperature an algal bloom is likely to develop. Such phenomena have been noticed on other shallow lakes using ERTS-1 and characterize eutrophic conditions. The concentration of the algae into long streamers provides additional information on surface circulations. To augment the ERTS-1 MSS data of Lake Erie an aircraft was flown to provide correlative thermal-IR and additional multiband photographs. The algal bloom is highly absorptive in the visible wavelengths but reverses contrast with the surrounding water in the near-IR bands. The absorption of shortwave energy heats the dark brown algal mass, providing a hot surface target for the thermal-IR scanner.

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

    SciTech Connect

    Claesson, A.

    1984-02-01

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

  3. Intensified nitrogen removal of constructed wetland by novel integration of high rate algal pond biotechnology.

    PubMed

    Ding, Yi; Wang, Wei; Liu, Xingpo; Song, Xinshan; Wang, Yuhui; Ullman, Jeffrey L

    2016-11-01

    High rate algal pond (HRAP) was combined with constructed wetland (CW) to intensify nitrogen removal through optimizing nitrification and denitrification. Nitrification and denitrification process mainly depends on the oxygen content and carbon source level in CWs. Algal biomass was enriched in HRAP, and dissolved oxygen (DO) concentration was increased via photosynthesis. Algal debris increased COD as degradable bioresource. The results showed that HRAP-CW hybrid systems effectively promoted the nitrogen removal performance due to rich DO and COD. The extension of hydraulic retention time in HRAP significantly improved NH4-N and TN removals by 10.9% and 11.1% in hybrid systems, respectively. The highest NH4-N and TN removals in hybrid systems respectively reached 67.2% and 63.5%, which were significantly higher than those in single CW. The study suggested that the hybrid system had the application potentials in nitrogen removal from wastewater. PMID:27544265

  4. Carbon Sequestration through Sustainably Sourced Algal Fertilizer: Deep Ocean Water.

    NASA Astrophysics Data System (ADS)

    Sherman, M. T.

    2014-12-01

    Drawing down carbon from the atmosphere happens in the oceans when marine plants are growing due to the use of carbon dioxide for biological processes and by raising the pH of the water. Macro- and microscopic marine photosynthesizers are limited in their growth by the availability of light and nutrients (nitrogen, phosphorous, iron, etc.) Deep ocean water (DOW), oceanic water from bellow about 1000m, is a natural medium for marine algae, which contains all (except in rare circumstances) necessary components for algal growth and represents over 90% of the volume of the ocean. The introduction of DOW to a tropical or summer sea can increase chlorophyll from near zero to 60 mg per M3 or more. The form of the utilization infrastructure for DOW can roughly be divided into two effective types; the unconstrained release and the open pond system. Unconstrained release has the advantage of having relatively low infrastructure investment and is available to any area of the ocean. The open pond system has high infrastructure costs but enables intensive use of DOW for harvesting macro- and microalgae and sustainable mariculture. It also enables greater concomitant production of DOW's other potential products such as electricity or potable water. However, unlike an unconstrained release the open pond system can capture much of the biomaterial from the water and limits the impact to the surrounding ecosystem. The Tidal Irrigation and Electrical System (TIESystem), is an open pond that is to be constructed on a continental shelf. It harnesses the tidal flux to pump DOW into the pond on the rising tide and then uses the falling tide to pump biologically rich material out of the pond. This biomaterial represents fixed CO2 and can be used for biofuel or fertilizers. The TIESystem benefits from an economy of scale that increases at a rate that is roughly equal to the relationship of the circumference of a circle (the barrier that creates the open pond) to the area of the pond

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    are easily distinguished. A threshold in graylevel allows to segment the image and to quantify the surface colonized by algae. The conversion process differentiates algal patches from dark slots caused by the rough relief. The covering rate depending on time is given by the ratio of colonized area to total surface. This experimental method proves that pH and roughness are determining in the biofouling mechanism.

  6. The engine of the reef: photobiology of the coral–algal symbiosis

    PubMed Central

    Roth, Melissa S.

    2014-01-01

    Coral reef ecosystems thrive in tropical oligotrophic oceans because of the relationship between corals and endosymbiotic dinoflagellate algae called Symbiodinium. Symbiodinium convert sunlight and carbon dioxide into organic carbon and oxygen to fuel coral growth and calcification, creating habitat for these diverse and productive ecosystems. Light is thus a key regulating factor shaping the productivity, physiology, and ecology of the coral holobiont. Similar to all oxygenic photoautotrophs, Symbiodinium must safely harvest sunlight for photosynthesis and dissipate excess energy to prevent oxidative stress. Oxidative stress is caused by environmental stressors such as those associated with global climate change, and ultimately leads to breakdown of the coral–algal symbiosis known as coral bleaching. Recently, large-scale coral bleaching events have become pervasive and frequent threatening and endangering coral reefs. Because the coral–algal symbiosis is the biological engine producing the reef, the future of coral reef ecosystems depends on the ecophysiology of the symbiosis. This review examines the photobiology of the coral–algal symbiosis with particular focus on the photophysiological responses and timescales of corals and Symbiodinium. Additionally, this review summarizes the light environment and its dynamics, the vulnerability of the symbiosis to oxidative stress, the abiotic and biotic factors influencing photosynthesis, the diversity of the coral–algal symbiosis, and recent advances in the field. Studies integrating physiology with the developing “omics” fields will provide new insights into the coral–algal symbiosis. Greater physiological and ecological understanding of the coral–algal symbiosis is needed for protection and conservation of coral reefs. PMID:25202301

  7. Slugs' last meals: molecular identification of sequestered chloroplasts from different algal origins in Sacoglossa (Opisthobranchia, Gastropoda).

    PubMed

    Händeler, Katharina; Wägele, Heike; Wahrmund, Ute; Rüdinger, Mareike; Knoop, Volker

    2010-11-01

    Some sacoglossan sea slugs have become famous for their unique capability to extract and incorporate functional chloroplasts from algal food organisms (mainly Ulvophyceae) into their gut cells. The functional incorporation of the so-called kleptoplasts allows the slugs to rely on photosynthetic products for weeks to months, enabling them to survive long periods of food shortage over most of their life-span. The algal food spectrum providing kleptoplasts as temporary, non-inherited endosymbionts appears to vary among sacoglossan slugs, but detailed knowledge is sketchy or unavailable. Accurate identification of algal donor species, which provide the chloroplasts for long-term retention is of primary importance to elucidate the biochemical mechanisms allowing long-term functionality of the captured chloroplast in the foreign animal cell environment. Whereas some sacoglossans forage on a variety of algal species, (e.g. Elysia crispata and E. viridis) others are more selective. Hence, characterizing the range of functional sacoglossan-chloroplast associations in nature is a prerequisite to understand the basis of this enigmatic endosymbiosis. Here, we present a suitable chloroplast gene (tufA) as a marker, which allows identification of the respective algal kleptoplast donor taxa by analysing DNA from whole animals. This novel approach allows identification of donor algae on genus or even species level, thus providing evidence for the taxonomic range of food organisms. We report molecular evidence that chloroplasts from different algal sources are simultaneously incorporated in some species of Elysia. NeigborNet analyses for species assignments are preferred over tree reconstruction methods because the former allow more reliable statements on species identification via barcoding, or rather visualize alternative allocations not to be seen in the latter. PMID:21565106

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

    PubMed

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

    2015-04-15

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

  9. The Hawaiian Freshwater Algal Database (HfwADB): a laboratory LIMS and online biodiversity resource

    PubMed Central

    2012-01-01

    Background Biodiversity databases serve the important role of highlighting species-level diversity from defined geographical regions. Databases that are specially designed to accommodate the types of data gathered during regional surveys are valuable in allowing full data access and display to researchers not directly involved with the project, while serving as a Laboratory Information Management System (LIMS). The Hawaiian Freshwater Algal Database, or HfwADB, was modified from the Hawaiian Algal Database to showcase non-marine algal specimens collected from the Hawaiian Archipelago by accommodating the additional level of organization required for samples including multiple species. Description The Hawaiian Freshwater Algal Database is a comprehensive and searchable database containing photographs and micrographs of samples and collection sites, geo-referenced collecting information, taxonomic data and standardized DNA sequence data. All data for individual samples are linked through unique 10-digit accession numbers (“Isolate Accession”), the first five of which correspond to the collection site (“Environmental Accession”). Users can search online for sample information by accession number, various levels of taxonomy, habitat or collection site. HfwADB is hosted at the University of Hawaii, and was made publicly accessible in October 2011. At the present time the database houses data for over 2,825 samples of non-marine algae from 1,786 collection sites from the Hawaiian Archipelago. These samples include cyanobacteria, red and green algae and diatoms, as well as lesser representation from some other algal lineages. Conclusions HfwADB is a digital repository that acts as a Laboratory Information Management System for Hawaiian non-marine algal data. Users can interact with the repository through the web to view relevant habitat data (including geo-referenced collection locations) and download images of collection sites, specimen photographs and

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

    NASA Astrophysics Data System (ADS)

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

    2008-07-01

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

  11. Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

    USGS Publications Warehouse

    Black, R.W.; Moran, P.W.; Frankforter, J.D.

    2011-01-01

    Many streams within the United States are impaired due to nutrient enrichment, particularly in agricultural settings. The present study examines the response of benthic algal communities in agricultural and minimally disturbed sites from across the western United States to a suite of environmental factors, including nutrients, collected at multiple scales. The first objective was to identify the relative importance of nutrients, habitat and watershed features, and macroinvertebrate trophic structure to explain algal metrics derived from deposition and erosion habitats. The second objective was to determine if thresholds in total nitrogen (TN) and total phosphorus (TP) related to algal metrics could be identified and how these thresholds varied across metrics and habitats. Nutrient concentrations within the agricultural areas were elevated and greater than published threshold values. All algal metrics examined responded to nutrients as hypothesized. Although nutrients typically were the most important variables in explaining the variation in each of the algal metrics, environmental factors operating at multiple scales also were important. Calculated thresholds for TN or TP based on the algal metrics generated from samples collected from erosion and deposition habitats were not significantly different. Little variability in threshold values for each metric for TN and TP was observed. The consistency of the threshold values measured across multiple metrics and habitats suggest that the thresholds identified in this study are ecologically relevant. Additional work to characterize the relationship between algal metrics, physical and chemical features, and nuisance algal growth would be of benefit to the development of nutrient thresholds and criteria. ?? 2010 The Author(s).

  12. Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams.

    PubMed

    Black, Robert W; Moran, Patrick W; Frankforter, Jill D

    2011-04-01

    Many streams within the United States are impaired due to nutrient enrichment, particularly in agricultural settings. The present study examines the response of benthic algal communities in agricultural and minimally disturbed sites from across the western United States to a suite of environmental factors, including nutrients, collected at multiple scales. The first objective was to identify the relative importance of nutrients, habitat and watershed features, and macroinvertebrate trophic structure to explain algal metrics derived from deposition and erosion habitats. The second objective was to determine if thresholds in total nitrogen (TN) and total phosphorus (TP) related to algal metrics could be identified and how these thresholds varied across metrics and habitats. Nutrient concentrations within the agricultural areas were elevated and greater than published threshold values. All algal metrics examined responded to nutrients as hypothesized. Although nutrients typically were the most important variables in explaining the variation in each of the algal metrics, environmental factors operating at multiple scales also were important. Calculated thresholds for TN or TP based on the algal metrics generated from samples collected from erosion and deposition habitats were not significantly different. Little variability in threshold values for each metric for TN and TP was observed. The consistency of the threshold values measured across multiple metrics and habitats suggest that the thresholds identified in this study are ecologically relevant. Additional work to characterize the relationship between algal metrics, physical and chemical features, and nuisance algal growth would be of benefit to the development of nutrient thresholds and criteria. PMID:20577796

  13. Fractional absorption of active absorbable algal calcium (AAACa) and calcium carbonate measured by a dual stable-isotope method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa), obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI), with that of calcium carbonate. In ...

  14. Effects of anodic oxidation of a substoichiometric titanium dioxide reactive electrochemical membrane on algal cell destabilization and lipid extraction.

    PubMed

    Hua, Likun; Guo, Lun; Thakkar, Megha; Wei, Dequan; Agbakpe, Michael; Kuang, Liyuan; Magpile, Maraha; Chaplin, Brian P; Tao, Yi; Shuai, Danmeng; Zhang, Xihui; Mitra, Somenath; Zhang, Wen

    2016-03-01

    Efficient algal harvesting, cell pretreatment and lipid extraction are the major steps challenging the algal biofuel industrialization. To develop sustainable solutions for economically viable algal biofuels, our research aims at devising innovative reactive electrochemical membrane (REM) filtration systems for simultaneous algal harvesting and pretreatment for lipid extraction. The results in this work particularly demonstrated the use of the Ti4O7-based REM in algal pretreatment and the positive impacts on lipid extraction. After REM treatment, algal cells exhibited significant disruption in morphology and photosynthetic activity due to the anodic oxidation. Cell lysis was evidenced by the changes of fluorescent patterns of dissolved organic matter (DOM) in the treated algal suspension. The lipid extraction efficiency increased from 15.2 ± 0.6 g-lipidg-algae(-1) for untreated algae to 23.4 ± 0.7 g-lipidg-algae(-1) for treated algae (p<0.05), which highlights the potential to couple algal harvesting with cell pretreatment in an integrated REM filtration process. PMID:26722810

  15. Alginate and Algal-Based Beads for the Sorption of Metal Cations: Cu(II) and Pb(II).

    PubMed

    Wang, Shengye; Vincent, Thierry; Faur, Catherine; Guibal, Eric

    2016-01-01

    Alginate and algal-biomass (Laminaria digitata) beads were prepared by homogeneous Ca ionotropic gelation. In addition, glutaraldehyde-crosslinked poly (ethyleneimine) (PEI) was incorporated into algal beads. The three sorbents were characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX): the sorption occurs in the whole mass of the sorbents. Sorption experiments were conducted to evaluate the impact of pH, sorption isotherms, and uptake kinetics. A special attention was paid to the effect of drying (air-drying vs. freeze-drying) on the mass transfer properties. For alginate, freeze drying is required for maintaining the porosity of the hydrogel, while for algal-based sorbents the swelling of the material minimizes the impact of the drying procedure. The maximum sorption capacities observed from experiments were 415, 296 and 218 mg Pb g(-1) and 112, 77 and 67 mg Cu g(-1) for alginate, algal and algal/PEI beads respectively. Though the sorption capacities of algal-beads decreased slightly (compared to alginate beads), the greener and cheaper one-pot synthesis of algal beads makes this sorbent more competitive for environmental applications. PEI in algal beads decreases the sorption properties in the case of the sorption of metal cations under selected experimental conditions. PMID:27598128

  16. Approaches for the detection of harmful algal blooms using oligonucleotide interactions.

    PubMed

    Bruce, Karen L; Leterme, Sophie C; Ellis, Amanda V; Lenehan, Claire E

    2015-01-01

    Blooms of microscopic algae in our waterways are becoming an increasingly important environmental concern. Many are sources of harmful biotoxins that can lead to death in humans, marine life and birds. Additionally, their biomass can cause damage to ecosystems such as oxygen depletion, displacement of species and habitat alteration. Globally, the number and frequency of harmful algal blooms has increased over the last few decades, and monitoring and detection strategies have become essential for managing these events. This review discusses developments in the use of oligonucleotide-based 'molecular probes' for the selective monitoring of algal cell numbers. Specifically, hybridisation techniques will be a focus. PMID:25381608

  17. Atmosphere behavior in gas-closed mouse-algal systems - An experimental and modelling study

    NASA Technical Reports Server (NTRS)

    Averner, M. M.; Moore, B., III; Bartholomew, I.; Wharton, R.

    1984-01-01

    A NASA-sponsored research program initiated using mathematical modelling and laboratory experimentation aimed at examining the gas-exchange characteristics of artificial animal/plant systems closed to the ambient atmosphere is studied. The development of control techniques and management strategies for maintaining the atmospheric levels of carbon dioxide and oxygen at physiological levels is considered. A mathematical model simulating the behavior of a gas-closed mouse-algal system under varying environmental conditions is described. To verify and validate the model simulations, an analytical system with which algal growth and gas exchange characteristics can be manipulated and measured is designed, fabricated, and tested. The preliminary results are presented.

  18. In Vitro Protocols for Measuring the Antioxidant Capacity of Algal Extracts.

    PubMed

    Kenny, Owen; Brunton, Nigel P; Smyth, Thomas J

    2015-01-01

    In the last decade a large amount of research has been directed at targeting algal resources for biologically active molecules. High-throughput in vitro antioxidant assays are routinely used to screen for biologically active compounds present in algal extracts when the requirement is to identify samples for progression to more detailed biological scrutiny. Whilst a myriad of antioxidant assays have been developed, this present chapter aims to give step-by-step practical guidance on how to carry out some of the most popular and biologically relevant assays at the bench. PMID:26108519

  19. Analysis of pollutant enhanced bacterial-blue-green algal interrelationships potentiating surface water contamination by noxious blue-green algal blooms. Completion report

    SciTech Connect

    Bedell, G.W.

    1984-02-01

    Sulfate-reducing bacteria from the genus Desulfovibro can stimulate the blue-green alga (Cyanobacterium) Anabaena variabilis (Strain 6411) into increasing its dry weight biomass production by more than 200 percent over that of the control as the total phosphate in the medium approaches zero. Results suggest that methods which utilize total nitrogen to phosphorus ratios in waters as predictors of blue-green algal 'blooms' may be unreliable when the waters are very low in phosphorus yet remain high in sulfate with conditions favorable for sulfate-reducing bacterial growth in benthic sediments. Otherwise, if the phosphate levels alone in the aqueous systems are reduced below threshold levels under these conditions, the magnitude of the blue-green algal blooms may be increased substantially.

  20. Biorefinery Technologies for Biomass Conversion Into Chemicals and Fuels Towards Zero Emissions (Review) / Nulles Emisiju Princips Biomasas Konversijas Tehnoloģijās Aizstājot Fosilos Resursus (Pārskata Raksts)

    NASA Astrophysics Data System (ADS)

    Gravitis, J.; Abolins, J.

    2013-10-01

    Exhausting of world resources, increasing pollution, and climate change are compelling the shift of the world economy from continuous growth to a kind of economy based on integration of technologies into zero emissions production systems. Transition from non-renewable fossil resources to renewable resources provided by solar radiation and the current processes in biosphere is seen in the bio-refinery approach - replacing crude oil refineries by biomass refineries. Biotechnology and nano-technologies are getting accepted as important players along with conventional biomass refinery technologies. Systems design is a significant element in the integration of bio-refinery technologies in clusters. A number of case-studies, steam explosion auto-hydrolysis (SEA) in particular, are reviewed to demonstrate conversion of biomass into value-added chemicals and fuels. Analysis of energy flows is made as part of modelling the SEA processes, the eMergy (energy memory) approach and sustainability indices being applied to assess environmental impacts. Resursu izsīkums, vides piesārņojums un globāla mēroga klimatiskās izmaiņas ir civilizācijas izdzīvošanai būtiski faktori, kas virza pasaules ekonomikas pārmaiņas, atsakoties no nepārtrauktas izaugsmes idejas par labu tādai ekonomikai, kas balstās uz atjaunojošamies resursiem un dažādu tehnoloģiju integrācijemisiju principam atbilstošās ražošanas sistēmās. Saules radiācijas ierosinātajos planētas biosfērā notiekošajos procesos radīto organisko vielu pārstrādes kompleksi, kas operē ievērojot sabalansētu nulles emisiju principu, tiek uzlūkoti kā tās ekonomiskās (ražošanas) struktūras, kurām jānodrošina pāreja uz atjaunojošos resursu izmantošanu, aizstājot esošās fosilo resursu (naftas, ogļu) pārstrādes rūpnīcas. Līdzās jau apgūtajām biomasas rafinēšanas tehnoloģijām svarīga un pieaugoša loma ekonomiskās sistēmas resursu bāzes nomaiņā ir bio- un nanotehnolo

  1. Yearlong evaluation of performance and durability of a pilot-scale Revolving Algal Biofilm (RAB) cultivation system.

    PubMed

    Gross, Martin; Wen, Zhiyou

    2014-11-01

    Current algal cultivation has been mainly performed in open ponds or photobioreactors in which algal cells are suspended and harvested through flocculation and centrifugation. A unique attachment based Revolving Algal Biofilm (RAB) cultivation system was recently developed for easy biomass harvest with enhanced biomass productivity. The objective of this research was to evaluate the performance (durability, algal growth, and the geometry) of the RAB system at pilot-scale. A yearlong test of the RAB system was successfully conducted at a greenhouse facility at Boone, Iowa, USA. The RAB resulted in an average of 302% increase in biomass productivity compared to a standard raceway pond, with a maximum biomass productivity (ash free) of 18.9 g/m(2)-day being achieved. The RAB with a vertical configuration generated higher productivity than the triangular RAB. Collectively, the research shows that the RAB as an efficient algal culture system has great potential for being deployed at commercial scale. PMID:25189508

  2. Recovery of algal oil from marine green macro-algae Enteromorpha intestinalis by acidic-hydrothermal process.

    PubMed

    Jeong, Gwi-Taek; Hong, Yong-Ki; Lee, Hyung-Ho; Kong, In-Soo; Kim, Joong Kyun; Park, Nam Gyu; Kim, Sung-Koo; Park, Don-Hee

    2014-09-01

    In this study, the recovery of algal oil from Enteromorpha intestinalis based on an acidic-hydrothermal reaction was investigated. Overall, the algal oil yield after the acidic-hydrothermal reaction was increased under the conditions of high reaction temperature, high catalyst concentration, and long reaction time within the tested ranges. Significantly, catalyst concentration, compared with reaction temperature and time, less affected algal oil recovery. The optimal acidic-hydrothermal reaction conditions for production of algal oil from E. intestinalis were as follows-200 °C reaction temperature, 2.92 % catalyst concentration, 54 min reaction time. Under these conditions, an 18.6 % algal oil yield was obtained. By increasing the combined severity factor, the algae oil recovery yield linearly increased. PMID:25055795

  3. Development of a rotating algal biofilm growth system for attached microalgae growth with in situ biomass harvest.

    PubMed

    Gross, Martin; Henry, Wesley; Michael, Clayton; Wen, Zhiyou

    2013-12-01

    This work aimed to develop a rotating algal biofilm (RAB) cultivation system that can be widely adopted by microalgae producers for easy biomass harvest. Algal cells were grown on the surface of a material rotating between nutrient-rich liquid and CO2-rich gaseous phase. Scrapping biomass from the attached surface avoided the expensive harvest operations such as centrifugation. Among various attachment materials, cotton sheet resulted in best algal growth, durability, and cost effectiveness. A lab-scale RAB system was further optimized with harvest frequency, rotation speed, and CO2 levels. The algal biomass from the RAB system had a similar water content as that in centrifuged biomass. An open pond raceway retrofitted with a pilot-scale RAB system resulted in a much higher biomass productivity when compared to a control open pond. Collectively, the research shows that the RAB system is an efficient algal culture system for easy biomass harvest with enhanced biomass productivity. PMID:24161650

  4. Nitrogen recycling from fuel-extracted algal biomass: residuals as the sole nitrogen source for culturing Scenedesmus acutus.

    PubMed

    Gu, Huiya; Nagle, Nick; Pienkos, Philip T; Posewitz, Matthew C

    2015-05-01

    In this study, the reuse of nitrogen from fuel-extracted algal residues was investigated. The alga Scenedesmus acutus was found to be able to assimilate nitrogen contained in amino acids, yeast extracts, and proteinaceous alga residuals. Moreover, these alternative nitrogen resources could replace nitrate in culturing media. The ability of S. acutus to utilize the nitrogen remaining in processed algal biomass was unique among the promising biofuel strains tested. This alga was leveraged in a recycling approach where nitrogen is recovered from algal biomass residuals that remain after lipids are extracted and carbohydrates are fermented to ethanol. The protein-rich residuals not only provided an effective nitrogen resource, but also contributed to a carbon "heterotrophic boost" in subsequent culturing, improving overall biomass and lipid yields relative to the control medium with only nitrate. Prior treatment of the algal residues with Diaion HP20 resin was required to remove compounds inhibitory to algal growth. PMID:25539998

  5. Process Design and Economics for the Conversion of Algal Biomass to Biofuels: Algal Biomass Fractionation to Lipid-and Carbohydrate-Derived Fuel Products

    SciTech Connect

    Davis, R.; Kinchin, C.; Markham, J.; Tan, E. C. D.; Laurens, L. M. L.; Sexton, D.; Knorr, D.; Schoen, P.; Lukas, J.

    2014-09-11

    The U.S. Department of Energy (DOE) promotes the production of a range of liquid fuels and fuel blendstocks from biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass production, conversion, and sustainability. As part of its involvement in this program, the National Renewable Energy Laboratory (NREL) investigates the conceptual production economics of these fuels. This includes fuel pathways from lignocellulosic (terrestrial) biomass, as well as from algal (aquatic) biomass systems.

  6. Competition between macroalgae and corals: effects of herbivore exclusion and increased algal biomass on coral survivorship and growth

    NASA Astrophysics Data System (ADS)

    Lirman, D.

    2001-05-01

    Recent declines in coral abundance accompanied by increases in macroalgal cover on Florida reefs highlight the importance of competition for space between these groups. This paper documents the frequency of coral-algal interactions on the Northern Florida Reef Tract and evaluates the effects of grazer exclusions and experimental algal addition on growth and tissue mortality of three coral species, Siderastrea siderea, Porites astreoides, and Montastraea faveolata. The frequency of interactions between corals and macroalgae was high as more than 50% of the basal perimeter of colonies was in contact with macroalgae; turf forms, Halimeda spp., and Dictyota spp. were the most common groups in contact with corals. Decreased grazing pressure resulted in significant increases in algal biomass within cages, and caged corals showed species-specific susceptibility to increased algal biomass. While no effects were detected for S. siderea, significant decreases in growth rates were documented for caged P. astreoides which had growth rates three to four times lower than uncaged colonies. When an algal addition treatment was included to duplicate maximum algal biomass levels documented for reefs in the area, colonies of P. astreoides in the algal addition treatment had growth rates up to ten times lower than uncaged colonies. High susceptibility to algal overgrowth was also found for the reef-building coral M. faveolata, which experienced significant tissue mortality under both uncaged (5.2% decrease in live tissue area per month) and caged (10.2% per month) conditions. The documented effects of increased algal biomass on coral growth and tissue mortality suggest a potential threat for the long-term survivorship and growth of corals in the Florida Reef Tract if present rates of algal growth and space utilization are maintained.

  7. Seasonal synchronicity of algal assemblages in three Midwestern agricultural streams having varying concentrations of atrazine, nutrients, and sediment.

    PubMed

    Andrus, J Malia; Winter, Diane; Scanlan, Michael; Sullivan, Sean; Bollman, Wease; Waggoner, J B; Hosmer, Alan J; Brain, Richard A

    2013-08-01

    Numerous studies characterizing the potential effects of atrazine on algal assemblages have been conducted using micro- or mesocosms; however, few evaluations focused on in situ lotic algal communities, potentially confounding risk assessment conclusions. This exploratory study, conducted at several sites in the midwestern United States where atrazine is commonly used, presents in situ observations of native algal communities relative to atrazine exposure and other parameters. Planktonic and periphytic algae from three streams in three Midwestern states, having historically differing atrazine levels, were sampled over a 16-week period in 2011 encompassing atrazine applications and the summer algal growth period at each site. Changes in abundance, diversity, and composition of algal communities were placed in the context of hydrological, climatic, and water quality parameters (including components sometimes present in agricultural runoff) also collected during the study. Diatoms dominated communities at each of the three sites and periphyton was much more abundant than phytoplankton. As expected, significant variations in algal community and environmental parameters were observed between sites. However, correspondence analysis plots revealed that patterns of temporal variation in algal communities at each site and in periphyton or phytoplankton were dominated by seasonal environmental gradients. Significant concordance in these seasonal patterns was detected among sites and between phytoplankton and periphyton communities (via procrustes Protest analysis), suggesting synchronicity of algal communities across a regional scale. While atrazine concentrations generally exhibited seasonal trends at the study watersheds; no effects on algal abundance, diversity or assemblage structure were observed as a result of atrazine pulses. This lack of response may be due to exposure events of insufficient concentration or duration (consistent with previously reported results) or

  8. Remote Sensing Marine Ecology: Wind-driven algal blooms in the open oceans and their ecological impacts

    NASA Astrophysics Data System (ADS)

    Tang, DanLing

    2016-07-01

    Algal bloom not only can increase the primary production but also could result in negative ecological consequence, e.g., Harmful Algal Blooms (HABs). According to the classic theory for the formation of algal blooms "critical depth" and "eutrophication", oligotrophic sea area is usually difficult to form a large area of algal blooms, and actually the traditional observation is only sporadic capture to the existence of algal blooms. Taking full advantage of multiple data of satellite remote sensing, this study: 1), introduces "Wind-driven algal blooms in open oceans: observation and mechanisms" It explained except classic coastal Ekman transport, the wind through a variety of mechanisms affecting the formation of algal blooms. Proposed a conceptual model of "Strong wind -upwelling-nutrient-phytoplankton blooms" in Western South China Sea (SCS) to assess role of wind-induced advection transport in phytoplankton bloom formation. It illustrates the nutrient resources that support long-term offshore phytoplankton blooms in the western SCS; 2), Proposal of the theory that "typhoons cause vertical mixing, induce phytoplankton blooms", and quantify their important contribution to marine primary production; Proposal a new ecological index for typhoon. Proposed remote sensing inversion models. 3), Finding of the spatial and temporaldistributions pattern of harmful algal bloom (HAB)and species variations of HAB in the South Yellow Sea and East China Sea, and in the Pearl River estuary, and their oceanic dynamic mechanisms related with monsoon; The project developed new techniques and generated new knowledge, which significantly improved understanding of the formation mechanisms of algal blooms. 1), It proposed "wind-pump" mechanism integrates theoretical system combing "ocean dynamics, development of algal blooms, and impact on primary production", which will benefit fisheries management. 2), A new interdisciplinary subject "Remote Sensing Marine Ecology"(RSME) has been

  9. Removal of algal blooms from freshwater by the coagulation-magnetic separation method.

    PubMed

    Liu, Dan; Wang, Peng; Wei, Guanran; Dong, Wenbo; Hui, Franck

    2013-01-01

    This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups. PMID:22767355

  10. The place of algae in agriculture: policies for algal biomass production.

    PubMed

    Trentacoste, Emily M; Martinez, Alice M; Zenk, Tim

    2015-03-01

    Algae have been used for food and nutraceuticals for thousands of years, and the large-scale cultivation of algae, or algaculture, has existed for over half a century. More recently algae have been identified and developed as renewable fuel sources, and the cultivation of algal biomass for various products is transitioning to commercial-scale systems. It is crucial during this period that institutional frameworks (i.e., policies) support and promote development and commercialization and anticipate and stimulate the evolution of the algal biomass industry as a source of renewable fuels, high value protein and carbohydrates and low-cost drugs. Large-scale cultivation of algae merges the fundamental aspects of traditional agricultural farming and aquaculture. Despite this overlap, algaculture has not yet been afforded a position within agriculture or the benefits associated with it. Various federal and state agricultural support and assistance programs are currently appropriated for crops, but their extension to algal biomass is uncertain. These programs are essential for nascent industries to encourage investment, build infrastructure, disseminate technical experience and information, and create markets. This review describes the potential agricultural policies and programs that could support algal biomass cultivation, and the barriers to the expansion of these programs to algae. PMID:24599393

  11. THE 'SELENASTRUM CAPRICORNUTUM' PRINTZ ALGAL ASSAY BOTTLE TEST: EXPERIMENTAL DESIGN, APPLICATION, AND DATA INTERPRETATION PROTOCOL

    EPA Science Inventory

    The document is the product of intensive research to improve and expand the understanding of results obtained from the Algal Assay Procedure: Bottle Test (USEPA 1971) to enable investigators to define the stimulatory and/or inhibitory interaction(s) of municipal, industrial and a...

  12. A Photosynthesis Lab. Response of Algal Suspensions to a Gradient of Photosynthetically Active Radiation (PAR).

    ERIC Educational Resources Information Center

    Zee, Delmar Vander

    1995-01-01

    This photosynthesis exercise is intended for introductory college biology or botany courses. It is based on the principle that a closed suspension of algal cells may be expected to produce more dissolved oxygen with a greater photon fluence rate, but within limits of the photosynthetic capacity of the system. Describes materials and methods. (LZ)

  13. Meteorological influences on algal bloom potential in a nutrient-rich blackwater river

    EPA Science Inventory

    The effect of variability in rainfall on the potential for algal blooms was examined for the St. Johns River in northeast Florida. Water chemistry and phytoplankton data were collected at selected sites monthly from 1993 through 2003. Information on rainfall and estimates ofw at...

  14. PCB UPTAKE AND ACCUMULATION BY OYSTERS (CRASSOSTREA VIRGINICA) EXPOSED VIA A CONTAMINATED ALGAL DIET. (R825349)

    EPA Science Inventory

    Abstract

    Reproductively active oysters were fed daily with 0.2 g algal paste containing 0, 0.1, and 1.0 small mu, Greekg polychlorinated biphenyls (PCBs) (1:1:1 mixture of Aroclor 1242, 1...

  15. Priming in the microbial landscape: periphytic algal stimulation of litter-associated microbial decomposers.

    PubMed

    Kuehn, Kevin A; Francoeur, Steven N; Findlay, Robert H; Neely, Robert K

    2014-03-01

    Microbial communities associated with submerged detritus in aquatic ecosystems often comprise a diverse mixture of autotrophic and heterotrophic microbes, including algae, bacteria, protozoa, and fungi. Recent studies have documented increased rates of plant litter mass loss when periphytic algae are present. We conducted laboratory and field experiments to assess potential metabolic interactions between natural autotrophic and heterotrophic microbial communities inhabiting submerged decaying plant litter of Typha angustifolia and Schoenoplectus acutus. In the field, submerged plant litter was either exposed to natural sunlight or placed under experimental canopies that manipulated light availability and growth of periphytic algae. Litter was collected and returned to the laboratory, where algal photosynthesis was manipulated (light/dark incubation), while rates of bacterial and fungal growth and productivity were simultaneously quantified. Bacteria and fungi were rapidly stimulated by exposure to light, thus establishing the potential for algal priming of microbial heterotrophic decay activities. Experimental incubations of decaying litter with 14C- and 13C-bicarbonate established that inorganic C fixed by algal photosynthesis was rapidly transferred to and assimilated by heterotrophic microbial decomposers. Periphytic algal stimulation of microbial heterotrophs, especially fungal decomposers, is an important and largely unrecognized interaction within the detrital microbial landscape, which may transform our current conceptual understanding of microbial secondary production and organic matter decomposition in aquatic ecosystems. PMID:24804458

  16. A PILOT PROJECT TO DETECT AND PREDICT HARMFUL ALGAL BLOOMS IN THE NORTHERN GULF OF MEXICO

    EPA Science Inventory

    More timely access to data and information on the initiation, evolution and effects of harmful algal blooms can reduce adverse impacts on valued natural resources and human health. To achieve this, a workshop was held to develop a user-driven, end-to-end (measurements to applicat...

  17. Modeling the impact of awareness on the mitigation of algal bloom in a lake.

    PubMed

    Misra, A K; Tiwari, P K; Venturino, Ezio

    2016-01-01

    The proliferation of algal bloom in water bodies due to the enhanced concentration of nutrient inflow is becoming a global issue. A prime reason behind this aquatic catastrophe is agricultural runoff, which carries a large amount of nutrients that make the lakes more fertile and cause algal blooms. The only solution to this problem is curtailing the nutrient loading through agricultural runoff. This could be achieved by raising awareness among farmers to minimize the use of fertilizers in their farms. In view of this, in this paper, we propose a mathematical model to study the effect of awareness among the farmers of the mitigation of algal bloom in a lake. The growth rate of awareness among the farmers is assumed to be proportional to the density of algae in the lake. It is further assumed that the presence of awareness among the farmers reduces the inflow rate of nutrients through agricultural runoff and helps to remove the detritus by cleaning the bottom of the lake. The results evoke that raising awareness among farmers may be a plausible factor for the mitigation of algal bloom in the lake. Numerical simulations identify the most critical parameters that influence the blooms and provide indications to possibly mitigate it. PMID:26411559

  18. Algal turf scrubbers: Periphyton production and nutrient recovery on a South Florida citrus farm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a strong need to develop strategies that reduce nutrient loading to Florida’s waters. The purpose of this study was to investigate the nutrient-removing ability and growth rate of periphyton, grown on an Algal Turf Scrubber (ATSTM) that received runoff from a citrus orchard operated by the ...

  19. Optimization of microwave-assisted transesterification of dry algal biomass using response surface methodology.

    PubMed

    Patil, Prafulla D; Gude, Veera Gnaneswar; Mannarswamy, Aravind; Cooke, Peter; Munson-McGee, Stuart; Nirmalakhandan, Nagamany; Lammers, Peter; Deng, Shuguang

    2011-01-01

    The effect of microwave irradiation on the simultaneous extraction and transesterification (in situ transesterification) of dry algal biomass to biodiesel was investigated. A high degree of oil/lipid extraction from dry algal biomass and an efficient conversion of the oils/lipids to biodiesel were demonstrated in a set of well-designed experimental runs. A response surface methodology (RSM) was used to analyze the influence of the process variables (dry algae to methanol (wt/vol) ratio, catalyst concentration, and reaction time) on the fatty acid methyl ester conversion. Based on the experimental results and RSM analysis, the optimal conditions for this process were determined as: dry algae to methanol (wt/vol) ratio of around 1:12, catalyst concentration about 2 wt.%, and reaction time of 4 min. The algal biodiesel samples were analyzed with GC-MS and thin layer chromatography (TLC) methods. Transmission electron microscopy (TEM) images of the algal biomass samples before and after the extraction/transesterification reaction are also presented. PMID:20933395

  20. Longitudinal Hydrodynamic Characteristics in Reservoir Tributary Embayments and Effects on Algal Blooms

    PubMed Central

    Dai, Huichao; Mao, Jingqiao; Jiang, Dingguo; Wang, Lingling

    2013-01-01

    Three Gorges Reservoir (TGR) is one of the largest man-made lakes in the world. Since the impoundment in 2003, however, algal blooms have been often observed in the tributary embayments. To control the algal blooms, a thorough understanding of the hydrodynamics (e.g., flow regime, velocity gradient, and velocity magnitude and direction) in the tributary embayments is particularly important. Using a calibrated three-dimensional hydrodynamic model, we carried out a hydrodynamic analysis of a typical tributary embayment (i.e., Xiangxi Bay) with emphasis on the longitudinal patterns. The results show distinct longitudinal gradients of hydrodynamics in the study area, which can be generally characterized as four zones: riverine, intermediate, lacustrine, and mainstream influenced zones. Compared with the typical longitudinal zonation for a pure reservoir, there is an additional mainstream influenced zone near the mouth due to the strong effects of TGR mainstream. The blooms are prone to occur in the intermediate and lacustrine zones; however, the hydrodynamic conditions of riverine and mainstream influence zones are not propitious for the formation of algal blooms. This finding helps to diagnose the sensitive areas for algal bloom occurrence. PMID:23874534

  1. Maintenance of algal endosymbionts in Paramecium bursaria: a simple model based on population dynamics.

    PubMed

    Iwai, Sosuke; Fujiwara, Kenji; Tamura, Takuro

    2016-09-01

    Algal endosymbiosis is widely distributed in eukaryotes including many protists and metazoans, and plays important roles in aquatic ecosystems, combining phagotrophy and phototrophy. To maintain a stable symbiotic relationship, endosymbiont population size in the host must be properly regulated and maintained at a constant level; however, the mechanisms underlying the maintenance of algal endosymbionts are still largely unknown. Here we investigate the population dynamics of the unicellular ciliate Paramecium bursaria and its Chlorella-like algal endosymbiont under various experimental conditions in a simple culture system. Our results suggest that endosymbiont population size in P. bursaria was not regulated by active processes such as cell division coupling between the two organisms, or partitioning of the endosymbionts at host cell division. Regardless, endosymbiont population size was eventually adjusted to a nearly constant level once cells were grown with light and nutrients. To explain this apparent regulation of population size, we propose a simple mechanism based on the different growth properties (specifically the nutrient requirements) of the two organisms, and based from this develop a mathematical model to describe the population dynamics of host and endosymbiont. The proposed mechanism and model may provide a basis for understanding the maintenance of algal endosymbionts. PMID:26625979

  2. Methods for collecting algal samples as part of the National Water-Quality Assessment Program

    USGS Publications Warehouse

    Porter, Stephen D.; Cuffney, Thomas F.; Gurtz, Martin E.; Meador, Michael R.

    1993-01-01

    Benthic algae (periphyton) and phytoplankton communities are characterized in the U.S. Geological Survey's National Water-Quality Assessment Program as part of an integrated physical, chemical, and biological assessment of the Nation's water quality. This multidisciplinary approach provides multiple lines of evidence for evaluating water-quality status and trends, and for refining an understanding of the factors that affect water-quality conditions locally, regionally, and nationally. Water quality can be characterized by evaluating the results of qualitative and quantitative measurements of the algal community. Qualitative periphyton samples are collected to develop of list of taxa present in the sampling reach. Quantitative periphyton samples are collected to measure algal community structure within selected habitats. These samples of benthic algal communities are collected from natural substrates, using the sampling methods that are most appropriate for the habitat conditions. Phytoplankton samples may be collected in large nonwadeable streams and rivers to meet specific program objectives. Estimates of algal biomass (chlorophyll content and ash-free dry mass) also are optional measures that may be useful for interpreting water-quality conditions. A nationally consistent approach provides guidance on site, reach, and habitat selection, as well as information on methods and equipment for qualitative and quantitative sampling. Appropriate quality-assurance and quality-control guidelines are used to maximize the ability to analyze data locally, regionally, and nationally.

  3. REVIEW OF THE CURRENT STATUS OF MARINE ALGAL TOXICITY TESTING IN THE UNITED STATES

    EPA Science Inventory

    Algal toxicity testing is not new, but only within the past few years have data from such testing been used to help set standards for allowable contamination. arly toxicity testing with marine algae used a few planktonic species with inhibition of growth as the primary endpoint. ...

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

    PubMed

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

    2013-11-01

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

  5. A MARINE ALGAL BIOASSAY METHOD: RESULTS WITH PESTICIDES AND INDUSTRIAL WASTES

    EPA Science Inventory

    A simple marine algal bioassay method is described for short- and long-term studies on pesticides and industrial wastes. It can be used for rapid screening of a variety of substances with single-species and multiple-species tests and gives relative toxicities of the pollutants te...

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

    PubMed Central

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

    2014-01-01

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

  7. Impact of Harmful Algal Blooms on Several Lake Erie Drinking Water Treatment Plants

    EPA Science Inventory

    Recent events in Ohio have demonstrated the challenge treatment facilities face in providing safe drinking water when encountering extreme harmful algal bloom (HAB) events. Over the last two years the impact of HAB-related microcystins on several drinking water treatment facilit...

  8. Determination of Total Solids and Ash in Algal Biomass: Laboratory Analytical Procedure (LAP)

    SciTech Connect

    Van Wychen, S.; Laurens, L. M. L.

    2013-12-01

    This procedure describes the methods used to determine the amount of moisture or total solids present in a freeze-dried algal biomass sample, as well as the ash content. A traditional convection oven drying procedure is covered for total solids content, and a dry oxidation method at 575?C is covered for ash content.

  9. MITIGATION OF HARMFUL ALGAL BLOOMS IN THE UNITED STATES USING CLAY: RESEARCH PROGRESS AND FUTURE PERSPECTIVES

    EPA Science Inventory

    Throughout the United States, red tides and harmful algal blooms (HABs) pose a serious and recurrent threat to marine ecosystems, fisheries, human health, and coastal aesthetics. Here we report results from a research program investigating the use of clay dispersal for bloom cont...

  10. BENTHIC AMPHIPOD COMMUNITY RESPONSE TO STRESS INDUCED BY ALGAL MATS IN A PACIFIC NORTHWEST ESTUARY

    EPA Science Inventory

    Amphipod, algal biomass and sediment samples were taken at two- to four-week intervals from June through December, 2000 along lines perpendicular to two transects in Yaquina Bay, OR, extending from within the Zostera marina bed at the river channel edge through intertidal burrowi...

  11. AMPHIPOD COMMUNITY RESPONSE TO STRESS INDUCED BY ALGAL MATS IN A PACIFIC NORTHWEST ESTUARY

    EPA Science Inventory

    Amphipod, algal and sediment samples were taken at two- to four-week intervals from June through December, 2000 along two transects in Yaquina Bay, OR. The transects extended from within the Zostera marina bed at the river channel edge through intertidal burrowing shrimp ...

  12. Herbivore Recolonization Rate Influences Light and Nutrient Effects on Algal Based Stream Ecosystems

    NASA Astrophysics Data System (ADS)

    Taulbee, K.

    2005-05-01

    The dynamics of algal based ecosystems are influenced by both resource availability and herbivory. Following a disturbance, the relative importance of top down versus bottom up regulation of algal dynamics in a particular system depends on both herbivore immigration rates and local resource availabilities. The effects of herbivore recolonization and resource availability on the recovery dynamics of algal ecosystems following a disturbance were investigated during two field experiments conducted in 24 in situ stream channels in Convict Creek, California. In each experiment, light and nutrients were cross-classified in a 6x2 factorial design, with 2 replicates per treatment. Initial algal and invertebrate densities were low. Using upstream drift nets of different mesh sizes, herbivore immigration was restricted in one experiment and unrestricted in a second experiment. The relative importance of herbivore versus resource regulation of algae was influenced by herbivore immigration. When immigration was restricted, as might occur following a severe disturbance, algae were more closely regulated by resource availability. In contrast, when herbivore immigration was not restricted, algae were regulated by both resource availability and herbivory. Finally, the effects of light and nutrients on algae were interactive when immigration was restricted, but not when immigration was unrestricted.

  13. WETLAND MORPHOLOGIC AND BIOGEOGRAPHIC INFLUENCES ON ALGAL RESPONSES TO NUTRIENT LOADING IN GREAT LAKES COASTAL WETLANDS

    EPA Science Inventory

    We are testing the influence of wetland morphology (protected vs. riverine) and biogeography (upper vs. lower Great Lakes) on algal responses to nutrients in Great Lakes Coastal wetlands. Principal components analysis using nutrient-specific GIS data was used to select sites wit...

  14. Growth of Heterotrophic Bacteria and Algal Extracellular Products in Oligotrophic Waters

    PubMed Central

    McFeters, Gordon A.; Stuart, Sidney A.; Olson, Susan B.

    1978-01-01

    The unexpected observation of 200 to 400 coliform bacteria per 100 ml in an unpolluted pristine stream was studied within Grand Teton National Park, Wyo. The high numbers of waterborne bacteria occurred in mid- to late summer at a location where there was a coincidental bloom of an algal mat community. Periphyton samplers were used to measure the algal growth that coincided with the increase in number of bacteria. Laboratory studies followed the growth of various coliform bacteria in the supernatant obtained from a Chlorella culture isolated from the mat community. Mixed natural bacterial populations from the stream and pure cultures of water-isolated fecal and nonfecal coliforms increased by two to three orders of magnitude at 13°C when grown in the algal supernatant. Radioactive algal products were obtained by feeding an axenic Chlorella culture 14C-labeled bicarbonate under laboratory cultivation at 13°C with illumination. Radioactive organic material from the algae became incorporated into the particulate fraction of pure cultures of coliform bacteria as they reproduced and was later released as they died. PMID:16345278

  15. Observations on gas exchange and element recycle within a gas-closed algal-mouse system

    NASA Technical Reports Server (NTRS)

    Smernoff, D. T.; Wharton, R. A., Jr.; Averner, M. M.

    1986-01-01

    Life support systems based on bioregeneration rely on the control and manipulation of organisms. Algae are potentially useful for a variety of Closed Ecological Life Support System (CELSS) functions including the revitalization of atmospheres, production of food and for nitrogen fixation. The results of experiments conducted with a gas-closed algal-mouse system designed to investigate gas exchange phenomena under varying algal environmental conditions, and the ability of algae to utilize oxidized mouse solid waste are reported. Inherent instabilities exist between the uptake and release of carbon dioxide (CO2) and oxygen (O2) by the mouse and algae in a gas-closed system. Variations in light intensity and cell density alter the photosynthetic rate of the algae and enable short-term steady-state concentrations of atmospheric CO2 and O2. Different nitrogen sources (urea and nitrate) result in different algal assimilatory quotients (AQ). Combinations of photosynthetic rate and AQ ratio manipulations were examined for their potential in stabilizing atmospheric gas concentrations in the gas-closed algal-mouse system.

  16. Methane and nitrous oxide emissions affect the life-cycle analysis of algal biofuels

    NASA Astrophysics Data System (ADS)

    Frank, Edward D.; Han, Jeongwoo; Palou-Rivera, Ignasi; Elgowainy, Amgad; Wang, Michael Q.

    2012-03-01

    Researchers around the world are developing sustainable plant-based liquid transportation fuels (biofuels) to reduce petroleum consumption and greenhouse gas emissions. Algae are attractive because they promise large yields per acre compared to grasses, grains and trees, and because they produce oils that might be converted to diesel and gasoline equivalents. It takes considerable energy to produce algal biofuels with current technology; thus, the potential benefits of algal biofuels compared to petroleum fuels must be quantified. To this end, we identified key parameters for algal biofuel production using GREET, a tool for the life-cycle analysis of energy use and emissions in transportation systems. The baseline scenario produced 55 400 g CO2 equivalent per million BTU of biodiesel compared to 101 000 g for low-sulfur petroleum diesel. The analysis considered the potential for greenhouse gas emissions from anaerobic digestion processes commonly used in algal biofuel models. The work also studied alternative scenarios, e.g., catalytic hydrothermal gasification, that may reduce these emissions. The analysis of the nitrogen recovery step from lipid-extracted algae (residues) highlighted the importance of considering the fate of the unrecovered nitrogen fraction, especially that which produces N2O, a potent greenhouse gas with global warming potential 298 times that of CO2.

  17. Freshwater harmful algal bloom exposure – an emerging health risk for recreational water users

    EPA Science Inventory

    Freshwater harmful algal bloom exposure – an emerging health risk for recreational water users Elizabeth D. Hilborn1, Virginia A. Roberts2, Lorraine C. Backer3, Jonathan S. Yoder2, Timothy J. Wade1, Michele C. Hlavsa2 1Environmental Public Health Division, Office of Researc...

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

    PubMed

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

    2001-11-01

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

  19. Predicting algal growth inhibition toxicity: three-step strategy using structural and physicochemical properties.

    PubMed

    Furuhama, A; Hasunuma, K; Hayashi, T I; Tatarazako, N

    2016-05-01

    We propose a three-step strategy that uses structural and physicochemical properties of chemicals to predict their 72 h algal growth inhibition toxicities against Pseudokirchneriella subcapitata. In Step 1, using a log D-based criterion and structural alerts, we produced an interspecies QSAR between algal and acute daphnid toxicities for initial screening of chemicals. In Step 2, we categorized chemicals according to the Verhaar scheme for aquatic toxicity, and we developed QSARs for toxicities of Class 1 (non-polar narcotic) and Class 2 (polar narcotic) chemicals by means of simple regression with a hydrophobicity descriptor and multiple regression with a hydrophobicity descriptor and a quantum chemical descriptor. Using the algal toxicities of the Class 1 chemicals, we proposed a baseline QSAR for calculating their excess toxicities. In Step 3, we used structural profiles to predict toxicity either quantitatively or qualitatively and to assign chemicals to the following categories: Pesticide, Reactive, Toxic, Toxic low and Uncategorized. Although this three-step strategy cannot be used to estimate the algal toxicities of all chemicals, it is useful for chemicals within its domain. The strategy is also applicable as a component of Integrated Approaches to Testing and Assessment. PMID:27171903

  20. THE TRPV1 RECEPTOR: THE INTERAGENCY, INTERNATION SYMPOSIUM ON CYANOBACTERIAL HARMFUL ALGAL BLOOMS.

    EPA Science Inventory

    Background and Significance

    Evidence indicates that the frequency of occurrence of cyanobacterial harmful algal blooms (CHABs) is increasing in spatial and temporal extent in the US and worldwide. Cyanotoxins are among the most potent toxins known, causing death through ...

  1. Controls on Pennsylvanian algal-mound distribution in mid-continent North America

    SciTech Connect

    Price, R.C.; Mitchell, J.C.; Ravn, R.L.

    1985-02-01

    Middle (Desmoinesian) and Upper (Missourian) Pennsylvanian phylloid algal-mound distribution in Missouri, Kansas, and Oklahoma is largely controlled by subtle sea-floor topography. Topographic highs served as loci favoring initiation and continued growth of complexes. Topographic highs controlling mound distribution are the shelf-edge rise in northeastern Oklahoma, the Bourbon arch in southeastern Kansas and the Mine Creek prodeltaic shale buildup in west-central Missouri. Outcrop studies document controls on development of these mounds and reveal the potential for development of stacked mounds. This will help exploration for these features in the subsurface to the west. The shelf-edge rise and Mine Creek prodeltaic shale buildup control the location of the Oologah algal-mound complex and an isolated algal mound in the Pawnee Limestone, respectively. These apparently were positive features only during Middle Pennsylvanian time. In contrast, the Bourbon arch apparently was controlled by basement faulting and remained high for a more-extended period of time. Both Middle and Upper Pennsylvanian algal mounds coincide with the geographic position of the Bourbon arch and result in a stacked-mound complex. Evidence suggesting that the Bourbon arch was a positive feature are (1) thinning of clastics over the feature and (2) change from anoxic, black, fissile, and phosphatic basinal shales to oxygenated, diversely fossiliferous gray shales over the arch.

  2. Phylogeny of Algal Sequences Encoding Carbohydrate Sulfotransferases, Formylglycine-Dependent Sulfatases, and Putative Sulfatase Modifying Factors

    PubMed Central

    Ho, Chai-Ling

    2015-01-01

    Many algae are rich sources of sulfated polysaccharides with biological activities. The physicochemical/rheological properties and biological activities of sulfated polysaccharides are affected by the pattern and number of sulfate moieties. Sulfation of carbohydrates is catalyzed by carbohydrate sulfotransferases (CHSTs) while modification of sulfate moieties on sulfated polysaccharides was presumably catalyzed by sulfatases including formylglycine-dependent sulfatases (FGly-SULFs). Post-translationally modification of Cys to FGly in FGly-SULFs by sulfatase modifiying factors (SUMFs) is necessary for the activity of this enzyme. The aims of this study are to mine for sequences encoding algal CHSTs, FGly-SULFs and putative SUMFs from the fully sequenced algal genomes and to infer their phylogenetic relationships to their well characterized counterparts from other organisms. Algal sequences encoding CHSTs, FGly-SULFs, SUMFs, and SUMF-like proteins were successfully identified from green and brown algae. However, red algal FGly-SULFs and SUMFs were not identified. In addition, a group of SUMF-like sequences with different gene structure and possibly different functions were identified for green, brown and red algae. The phylogeny of these putative genes contributes to the corpus of knowledge of an unexplored area. The analyses of these putative genes contribute toward future production of existing and new sulfated carbohydrate polymers through enzymatic synthesis and metabolic engineering. PMID:26635861

  3. Beach-goer behavior during a retrospectively detected algal bloom at a Great Lakes beach

    EPA Science Inventory

    Algal blooms occur among nutrient rich, warm surface waters and may adversely impact recreational beaches. During July – September 2003, a prospective study of beachgoers was conducted on weekends at a public beach on a Great Lake in the United States. We measured each beac...

  4. A PILOT PROJECT TO DETECT AND FORECAST HARMFUL ALGAL BLOOMS IN THE NORTHERN GULF OF MEXICO

    EPA Science Inventory

    More timely access to data and information on the initiation, evolution and effects of harmful algal blooms can reduce adverse impacts on valued natural resources and human health. To achieve this in the northern Gulf of Mexico, a pilot project was initiated to develop a user-dr...

  5. Post-extraction algal residue in steam-flaked corn-based diets for beef cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of post-extraction algal residue (PEAR) as N source 23 in steam-flaked corn-based (SFC) beef cattle finishing diets on intake, duodenal flow, digestion, ruminal microbial efficiency, ruminal parameters, and blood constituents were evaluated. Ruminally and duodenally cannulated steers (BW...

  6. Monitoring of ocean surface algal blooms in coastal and oceanic waters around India.

    PubMed

    Tholkapiyan, Muniyandi; Shanmugam, Palanisamy; Suresh, T

    2014-07-01

    The National Aeronautics and Space Administration's (NASA) sensor MODIS-Aqua provides an important tool for reliable observations of the changing ocean surface algal bloom paradigms in coastal and oceanic waters around India. A time series of the MODIS-Aqua-derived OSABI (ocean surface algal bloom index) and its seasonal composite images report new information and comprehensive pictures of these blooms and their evolution stages in a wide variety of events occurred at different times of the years from 2003 to 2011, providing the first large area survey of such phenomena around India. For most of the years, the results show a strong seasonal pattern of surface algal blooms elucidated by certain physical and meteorological conditions. The extent of these blooms reaches a maximum in winter (November-February) and a minimum in summer (June-September), especially in the northern Arabian Sea. Their spatial distribution and retention period are also significantly increased in the recent years. The increased spatial distribution and intensity of these blooms in the northern Arabian Sea in winter are likely caused by enhanced cooling, increased convective mixing, favorable winds, and atmospheric deposition of the mineral aerosols (from surrounding deserts) of the post-southwest monsoon period. The southward Oman coastal current and southwestward winds become apparently responsible for their extension up to the central Arabian Sea. Strong upwelling along this coast further triggers their initiation and growth. Though there is a warming condition associated with increased sea surface height anomalies along the coasts of India and Sri Lanka in winter, surface algal bloom patches are still persistent along these coasts due to northeast monsoonal winds, enhanced precipitation, and subsequent nutrient enrichment in these areas. The occurrence of the surface algal blooms in the northern Bay of Bengal coincides with a region of the well-known Ganges-Brahmaputra Estuarine Frontal

  7. Phylogenetic Analysis of Algal Symbionts Associated with Four North American Amphibian Egg Masses

    PubMed Central

    Kim, Eunsoo; Lin, Yuan; Kerney, Ryan; Blumenberg, Lili; Bishop, Cory

    2014-01-01

    Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga “Oophila amblystomatis” (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the ‘Oophila’ clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae. PMID:25393119

  8. Development of algal interspecies correlation estimation models for chemical hazard assessment.

    PubMed

    Brill, Jessica L; Belanger, Scott E; Chaney, Joel G; Dyer, Scott D; Raimondo, Sandy; Barron, Mace G; Pittinger, Charles A

    2016-09-01

    Web-based Interspecies Correlation Estimation (ICE) is an application developed to predict the acute toxicity of a chemical from 1 species to another taxon. Web-ICE models use the acute toxicity value for a surrogate species to predict effect values for other species, thus potentially filling in data gaps for a variety of environmental assessment purposes. Web-ICE has historically been dominated by aquatic and terrestrial animal prediction models. Web-ICE models for algal species were essentially absent and are addressed in the present study. A compilation of public and private sector-held algal toxicity data were compiled and reviewed for quality based on relevant aspects of individual studies. Interspecies correlations were constructed from the most commonly tested algal genera for a broad spectrum of chemicals. The ICE regressions were developed based on acute 72-h and 96-h endpoint values involving 1647 unique studies on 476 unique chemicals encompassing 40 genera and 70 species of green, blue-green, and diatom algae. Acceptance criteria for algal ICE models were established prior to evaluation of individual models and included a minimum sample size of 3, a statistically significant regression slope, and a slope estimation parameter ≥0.65. A total of 186 ICE models were possible at the genus level, with 21 meeting quality criteria; and 264 ICE models were developed at the species level, with 32 meeting quality criteria. Algal ICE models will have broad utility in screening environmental hazard assessments, data gap filling in certain regulatory scenarios, and as supplemental information to derive species sensitivity distributions. Environ Toxicol Chem 2016;35:2368-2378. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. PMID:26792236

  9. Norwegian remote sensing spectrometry for mapping and monitoring of algal blooms and pollution - NORSMAP-89

    SciTech Connect

    Pettersson, L.H.; Johannessen, O.M.; Frette, O. )

    1990-01-09

    During the late spring of 1988 an extensive bloom of the toxic algae Chrysocromulina polylepis occurred in the Skagerrak region influencing most life in the upper 30 meter of the ocean. The algal front was advected northward with the Norwegian Coastal Current along the coast of southern Norway, where it became a severe threat to the Norwegian seafarming industry. An ad-hoc expert team was established to monitor and forecast the movement of the algae front. Remote sensing of sea surface temperature from the operational US NOAA satellites monitored the movement of the algal front, consistent with a warm ocean front. The lack of any optical remote sensing instrumentation was recognized as a major de-efficiency during this algal bloom. To prepare for similar events in the future Nansen Remote Sensing Center initiated a three week pilot study in the Oslofjord and Skagerrak region, during May 1989. The Canadian Compact Airborne Spectrographic Imager (CASI) was installed in the surveillance aircraft. Extensive in situ campaigns was also carried out by the Norwegian Institute for Water Research and Institute of Marine Research. A ship-borne non-imaging spectrometer was operated from the vessels participating in the field campaign. As a contribution from a joint campaign (EISAC '89) between the Joint Research Centre (JRC) of the European Community and the European Space Agency (ESA) both the Canadian Fluorescence Line Imager (FLI) and the US 64-channel GER scanner was operated simultaneously at the NORSMAP 89 test site. Regions of different biological and physical conditions were covered during the pilot study and preliminary analysis are obtained from oil slicks, suspended matter from river, as well as minor algal bloom. The joint analysis of the data collected during the NORSMAP 89 campaign and conclussions will be presented, as well as suggestions for future utilization of airborne spectroscopy systems for operational monitoring of algal bloom and water pollution.

  10. Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses.

    PubMed

    Kim, Eunsoo; Lin, Yuan; Kerney, Ryan; Blumenberg, Lili; Bishop, Cory

    2014-01-01

    Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga "Oophila amblystomatis" (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae. PMID:25393119

  11. Controlling silver nanoparticle exposure in algal toxicity testing – A matter of timing

    PubMed Central

    Baun, Anders

    2015-01-01

    The aquatic ecotoxicity testing of nanoparticles is complicated by unstable exposure conditions resulting from various transformation processes of nanoparticles in aqueous suspensions. In this study, we investigated the influence of exposure timing on the algal test response to silver nanoparticles (AgNPs), by reducing the incubation time and by aging the AgNPs in algal medium prior to testing. The freshwater green algae Pseudokirchneriella subcapitata were exposed to AgNO3, NM-300 K (a representative AgNP) and citrate stabilized AgNPs from two different manufacturers (AgNP1 and AgNP2) in a standard algal growth inhibition test (ISO 8692:2004) for 48 h and a short-term (2 h) 14C-assimilation test. For AgNO3, similar responses were obtained in the two tests, whereas freshly prepared suspensions of citrate stabilized AgNPs were less toxic in the 2-h tests compared to the 48-h tests. The 2-h test was found applicable for dissolved silver, but yielded non-monotonous concentration–response relationships and poor reproducibility for freshly prepared AgNP suspensions. However, when aging AgNPs in algal medium 24 h prior to testing, clear concentration–response patterns emerged and reproducibility increased. Prolonged aging to 48 h increased toxicity in the 2-h tests whereas aging beyond 48 h reduced toxicity. Our results demonstrate that the outcome of algal toxicity testing of AgNPs is highly influenced not only by the test duration, but also by the time passed from the moment AgNPs are added to the test medium. This time-dependency should be considered when nanomaterial dispersion protocols for ecotoxicity testing are developed. PMID:24842597

  12. Primary production of edaphic algal communities in a Mississippi salt marsh

    SciTech Connect

    Sullivan, M.J.; Moncreiff, C.A.

    1988-03-01

    Primary production rates of edaphic algae associated with the sediments beneath four monospecific canopies of vascular plants were determined over an annual cycle in a Mississippi salt marsh. The edaphic algal flora was dominated by small, motile pennate diatoms. Algal production (as measured by /sup 14/C uptake) was generally highest in spring-early summer and lowest in fall. Hourly rates ranged from a low of 1.4 mg C/m/sup 2/ in Juncus roemerianus Scheele to a high of 163 mg C/m/sup 2/ beneath the Scirpus olneyi Gray canopy. Stepwise multiple regressions identified a soil moisture index and chlorophyll a as the best environmental predictors of hourly production; light energy reaching the marsh surface and sediment and air temperature proved of little value. Adding the relative abundances of 33 diatom taxa to the set of independent variables only slightly increased R/sup 2/; however, virtually all variables selected were diatom taxa. R/sup 2/ was only 0.38 for the Spartina alterniflora Loisel. habitat but ranged from 0.70 to 0.87 for the remaining three vascular plant zones. Annual rates of algal production (g C/m/sup 2/) were estimated as follows: Juncus (28), Spartina (57), Distichlis spicata (L.) Greene (88), and Scirpus (151). The ratio of annual edaphic algal production to vascular plant net aerial production (EAP/VPP) was 10-12% for the first three habitats and 61% for Scirpus. Chlorophyll a concentrations, annual algal production rates, and EAP/VPP values were comparable to those determined in Texas, Delaware, and Massachusetts salt marshes but lower than those reported for Georgia and particularly California marshes.

  13. Controlling silver nanoparticle exposure in algal toxicity testing--a matter of timing.

    PubMed

    Sørensen, Sara Nørgaard; Baun, Anders

    2015-03-01

    The aquatic ecotoxicity testing of nanoparticles is complicated by unstable exposure conditions resulting from various transformation processes of nanoparticles in aqueous suspensions. In this study, we investigated the influence of exposure timing on the algal test response to silver nanoparticles (AgNPs), by reducing the incubation time and by aging the AgNPs in algal medium prior to testing. The freshwater green algae Pseudokirchneriella subcapitata were exposed to AgNO3, NM-300 K (a representative AgNP) and citrate stabilized AgNPs from two different manufacturers (AgNP1 and AgNP2) in a standard algal growth inhibition test (ISO 8692:2004) for 48 h and a short-term (2 h) (14)C-assimilation test. For AgNO3, similar responses were obtained in the two tests, whereas freshly prepared suspensions of citrate stabilized AgNPs were less toxic in the 2-h tests compared to the 48-h tests. The 2-h test was found applicable for dissolved silver, but yielded non-monotonous concentration-response relationships and poor reproducibility for freshly prepared AgNP suspensions. However, when aging AgNPs in algal medium 24 h prior to testing, clear concentration-response patterns emerged and reproducibility increased. Prolonged aging to 48 h increased toxicity in the 2-h tests whereas aging beyond 48 h reduced toxicity. Our results demonstrate that the outcome of algal toxicity testing of AgNPs is highly influenced not only by the test duration, but also by the time passed from the moment AgNPs are added to the test medium. This time-dependency should be considered when nanomaterial dispersion protocols for ecotoxicity testing are developed. PMID:24842597

  14. Responses of algal communities to gradients in herbivore biomass and water quality in Marovo Lagoon, Solomon Islands

    NASA Astrophysics Data System (ADS)

    Albert, S.; Udy, J.; Tibbetts, I. R.

    2008-03-01

    Settlement tiles were used to characterise and quantify coral reef associated algal communities along water quality and herbivory gradients from terrestrial influenced near shore sites to oceanic passage sites in Marovo Lagoon, the Solomon Islands. After 6 months, settlement tile communities from inshore reefs were dominated by high biomass algal turfs (filamentous algae and cyanobacteria) whereas tiles located on offshore reefs were characterised by a mixed low biomass community of calcareous crustose algae, fleshy crustose algae and bare tile. The exclusion of macrograzers, via caging of tiles, on the outer reef sites resulted in the development of an algal turf community similar to that observed on inshore reefs. Caging on the inshore reef tiles had a limited impact on community composition or biomass. Water quality and herbivorous fish biomass were quantified at each site to elucidate factors that might influence algal community structure across the lagoon. Herbivore biomass was the dominant driver of algal community structure. Algal biomass on the other hand was controlled by both herbivory and water quality (particularly dissolved nutrients). This study demonstrates that algal communities on settlement tiles are an indicator capable of integrating the impacts of water quality and herbivory over a small spatial scale (kilometres) and short temporal scale (months), where other environmental drivers (current, light, regional variability) are constant.

  15. Effect of wastewater-borne bacteria on algal growth and nutrients removal in wastewater-based algae cultivation system.

    PubMed

    Ma, Xiaochen; Zhou, Wenguang; Fu, Zongqiang; Cheng, Yanling; Min, Min; Liu, Yuhuan; Zhang, Yunkai; Chen, Paul; Ruan, Roger

    2014-09-01

    Centrate, a type of nutrient-rich municipal wastewater was used to determine the effect of wastewater-borne bacteria on algal growth and nutrients removal efficiency in this study. The characteristics of algal and bacterial growth profiles, wastewater nutrient removal and effect of initial algal inoculums were systematically examined. The results showed that initial algal concentration had apparent effect on bacterial growth, and the presence of bacteria had a significant influence on algal growth pattern, suggesting symbiotic relationship between algae and bacteria at the initial stage of algae cultivation. The maximum algal biomass of 2.01 g/L with 0.1g/L initial algal inoculums concentration can be obtained during algae cultivation in raw centrate medium. The synergistic effect of centrate-borne bacteria and microalgae on algae growth and nutrient removal performance at initial fast growth stage has great potential to be applied to pilot-scale wastewater-based algae wastewater system cultivated in continuous or semi-continuous mode. PMID:24968106

  16. Relations between water physico-chemistry and benthic algal communities in a northern Canadian watershed: defining reference conditions using multiple descriptors of community structure.

    PubMed

    Thomas, Kathryn E; Hall, Roland I; Scrimgeour, Garry J

    2015-09-01

    Defining reference conditions is central to identifying environmental effects of anthropogenic activities. Using a watershed approach, we quantified reference conditions for benthic algal communities and their relations to physico-chemical conditions in rivers in the South Nahanni River watershed, NWT, Canada, in 2008 and 2009. We also compared the ability of three descriptors that vary in terms of analytical costs to define algal community structure based on relative abundances of (i) all algal taxa, (ii) only diatom taxa, and (iii) photosynthetic pigments. Ordination analyses showed that variance in algal community structure was strongly related to gradients in environmental variables describing water physico-chemistry, stream habitats, and sub-watershed structure. Water physico-chemistry and local watershed-scale descriptors differed significantly between algal communities from sites in the Selwyn Mountain ecoregion compared to sites in the Nahanni-Hyland ecoregions. Distinct differences in algal community types between ecoregions were apparent irrespective of whether algal community structure was defined using all algal taxa, diatom taxa, or photosynthetic pigments. Two algal community types were highly predictable using environmental variables, a core consideration in the development of Reference Condition Approach (RCA) models. These results suggest that assessments of environmental impacts could be completed using RCA models for each ecoregion. We suggest that use of algal pigments, a high through-put analysis, is a promising alternative compared to more labor-intensive and costly taxonomic approaches for defining algal community structure. PMID:26255271

  17. Enhancing biomass energy yield from pilot-scale high rate algal ponds with recycling.

    PubMed

    Park, J B K; Craggs, R J; Shilton, A N

    2013-09-01

    This paper investigates the effect of recycling on biomass energy yield in High Rate Algal Ponds (HRAPs). Two 8 m(3) pilot-scale HRAPs treating primary settled sewage were operated in parallel and monitored over a 2-year period. Volatile suspended solids were measured from both HRAPs and their gravity settlers to determine biomass productivity and harvest efficiency. The energy content of the biomass was also measured. Multiplying biomass productivity and harvest efficiency gives the 'harvestable biomass productivity' and multiplying this by the energy content defines the actual 'biomass energy yield'. In Year 1, algal recycling was implemented in one of the ponds (HRAPr) and improved harvestable biomass productivity by 58% compared with the control (HRAPc) without recycling (HRAPr: 9.2 g/m(2)/d; HRAPc: 5.8 g/m(2)/d). The energy content of the biomass grown in HRAPr, which was dominated by Pediastrun boryanum, was 25% higher than the control HRAPc which contained a mixed culture of 4-5 different algae (HRAPr: 21.5 kJ/g; HRAPc: 18.6 kJ/g). In Year 2, HRAPc was then seeded with the biomass harvested from the P. boryanum dominated HRAPr. This had the effect of shifting algal dominance from 89% Dictyosphaerium sp. (which is poorly-settleable) to over 90% P. boryanum in 5 months. Operation of this pond was then switched to recycling its own harvested biomass, which maintained P. boryanum dominance for the rest of Year 2. This result confirms, for the first time in the literature, that species control is possible for similarly sized co-occurring algal colonies in outdoor HRAP by algal recycling. With regard to the overall improvement in biomass energy yield, which is a critical parameter in the context of algal cultivation for biofuels, the combined improvements that recycling triggered in biomass productivity, harvest efficiency and energy content enhanced the harvested biomass energy yield by 66% (HRAPr: 195 kJ/m(2)/day; HRAPc: 118 kJ/m(2)/day). PMID:23764593

  18. Sequential removal of heavy metals ions and organic pollutants using an algal-bacterial consortium.

    PubMed

    Muñoz, Raul; Alvarez, Maria Teresa; Muñoz, Adriana; Terrazas, Enrique; Guieysse, Benoit; Mattiasson, Bo

    2006-05-01

    The residual algal-bacterial biomass from photosynthetically supported, organic pollutant biodegradation processes, in enclosed photobioreactors, was tested for its ability to accumulate Cu(II), Ni(II), Cd(II), and Zn(II). Salicylate was chosen as a model contaminant. The algal-bacterial biomass combined the high adsorption capacity of microalgae with the low cost of the residual biomass, which makes it an attractive biosorbent for environmental applications. Cu(II) was preferentially taken-up from the medium when the metals were present both separately and in combination. There was no observed competition for adsorption sites, which suggested that Cu(II), Ni(II), Cd(II), and Zn(II) bind to different sites and that active Ni(II), Cd(II) and Zn(II) binding groups were present at very low concentrations. Therefore, special focus was given to Cu(II) biosorption. Cu(II) biosorption by the algal-bacterial biomass was characterized by an initial fast cell surface adsorption followed by a slower metabolically driven uptake. pH, Cu(II), and algal-bacterial concentration significantly affected the biosorption capacity for Cu(II). Maximum Cu(II) adsorption capacities of 8.5+/-0.4 mg g-1 were achieved at an initial Cu(II) concentration of 20 mg l-1 and at pH 5 for the tested algal-bacterial biomass. These are consistent with values reported for other microbial sorbents under similar conditions. The desorption of Cu(II) from saturated biomass was feasible by elution with a 0.0125 M HCl solution. Simultaneous Cu(II) and salicylate removal in a continuous stirred tank photobioreactor was not feasible due to the high toxicity of Cu(II) towards the microbial culture. The introduction of an adsorption column, packed with the algal-bacterial biomass, prior to the photobioreactor reduced Cu(II) concentration, thereby allowing the subsequent salicylate biodegradation in the photobioreactor. PMID:16307789

  19. Transformation of Swine Manure and Algal Consortia to Value-added Products

    NASA Astrophysics Data System (ADS)

    Sharara, Mahmoud A.

    The swine production sector is projected to grow globally. In the past, this growth manifested itself in increased herd sizes and geographically concentrated production. Although economically sound, these trends had negative consequences on surrounding ecosystems. Over-application of manure resulted in water quality degradation, while long-term storage of manure slurries was found to promote release of potent GHG emissions. There is a need for innovative approaches for swine manure management that are compatible with current scales of production, and increasingly strict environmental regulations. This study aims to investigate the potential for incorporating gasification as part of a novel swine manure management system which utilizes liquid-solid separation and periphytic algal consortia as a phycoremediation vector for the liquid slurry. The gasification of swine manure solids, and algal biomass solids generate both a gaseous fuel product (producer gas) in addition to a biochar co-product. First, the decomposition kinetics for both feedstock, i.e., swine manure solids, and algal solids, were quantified using thermogravimetry at different heating rates (1 ~ 40°C min-1) under different atmospheres (nitrogen, and air). Pyrolysis kinetics were determined for manure solids from two farms with different manure management systems. Similarly, the pyrolysis kinetics were determined for phycoremediation algae grown on swine manure slurries. Modeling algal solids pyrolysis as first-order independent parallel reactions was sufficient to describe sample devolatilization. Combustion of swine manure solids blended with algal solids, at different ratios, showed no synergistic effects. Gasification of phycoremediation algal biomass was studied using a bench-scale auger gasification system at temperatures between 760 and 960°C. The temperature profile suggested a stratification of reaction zones common to fixed-bed reactors. The producer gas heating value ranged between 2.2 MJ m

  20. Algal pigments record shifts in dominant primary productivity through the Holocene in an arctic lake

    NASA Astrophysics Data System (ADS)

    Florian, C.; Miller, G. H.; Fogel, M. L.

    2011-12-01

    The character and magnitude of primary productivity in arctic lakes is largely controlled by climate. Organic compounds derived from pigments and preserved in lake sediments allow reconstruction of past abundances of algae that do not leave silicious microfossils. Fossil algal pigments are abundant in lake sediment and can be accurately quantified using High Pressure Liquid Chromatography (HPLC). Several groups of algae produce unique pigments that can be used to reconstruct their past abundance. In Qivitu Highlands Lake, eastern central Baffin Island, the ratio of pigments diatoxantin and lutein exhibits coherent changes through the Holocene. Diatoxanthin is produced by diatoms and chrysophytes, whereas lutein is produced by green algae and higher plants. Because these pigments are the dominant carotenoids in the sediment, they serve as proxies for the dominant group of primary producers. During the Holocene Thermal Maximum and the past century, lutein is much more abundant than diatoxanthin. During Neoglacial cooling and into the Little Ice Age, diatoxanthin becomes the dominant carotenoid. This shift reveals that there was a change in not only the magnitude of algal production, but also the most abundant type. The adaptation of aquatic algal assemblages to changing climate suggests that gross changes in primary productivity may not be suitable to track the abundance of one type of algal microfossil (such as diatoms) without considering the other algal groups. Higher plants also produce lutein, and its abundance is additionally influenced by the presence of terrestrial organic matter as well as aquatic macrophyte plants. We hypothesize that the prevalence of lutein during warm summers is due to a longer ice-free season, allowing the development of a greater biomass of green algae and macrophyte plants as well as possible increases of terrestrial higher plant communities. This is part of a larger study where the lutein to diatoxanthin ratio is compared to organic

  1. Algal populations controlled by fish herbivory across a wave exposure gradient on southern temperate shores.

    PubMed

    Taylor, David I; Schiel, David R

    2010-01-01

    Consumers that forage across habitats can affect communities by altering the abundance and distribution of key species. In marine communities, studies of trophic interactions have generally focused on the effects of herbivorous and predatory invertebrates on benthic algae and mussel populations. However, large mobile consumers that move across habitats, such as fishes, can strongly affect community dynamics through consumption of habitat-dominating species, but their effects often vary over environmental gradients. On temperate rocky shores, herbivorous fishes are generally a small part of the fish fauna compared to the tropics, and there is sparse evidence that they play a major direct role in algal community dynamics, particularly of large brown algae that dominate many reefs. In New Zealand, however, a wide-ranging herbivorous fish, Odax pullus, feeds exclusively on macroalgae, including Durvillaea antarctica, a large low-intertidal fucoid reaching 10 m in length and 70 kg in mass. In four experiments we tested the extent of fish herbivory and how it was affected by algal canopy structure across a gradient of wave exposure at multiple sites. Exclusion experiments showed that fish impacts greatly reduced the cover and biomass of Durvillaea and that these effects decreased with increasing wave stress and algal canopy cover, effectively restricting the alga to exposed conditions. Almost all plants were entirely removed by fish where there was a sparse algal canopy in sheltered and semi-exposed sites, but there was significantly less grazing in exposed sites. Recruit Durvillaea beneath canopies were less affected by fish grazing, but they grew slowly. Successful natural recruitment, therefore, occurred almost exclusively on exposed shores outside canopies where many plants escaped severe grazing, and growth to maturity was far greater than elsewhere. Such large and direct impacts on the local and regional distribution of large brown algal populations by mobile

  2. Non-conventional approaches to food processing in CELSS. I-algal proteins; characterization and process optimization

    NASA Astrophysics Data System (ADS)

    Nakhost, Z.; Karel, M.; Krukonis, V. J.

    Protein isolate obtained from green algae (Scenedesmus obliquus) cultivated under controlled conditions was characterized. Molecular weight determination of fractionated algal proteins using SDS-polyacrylamide gel electrophoresis revealed a wide spectrum of molecular weights ranging from 15,000 to 220,000. Isoelectric points of dissociated proteins were in the range of 3.95 to 6.20. Amino acid composition of protein isolate compared favorably with FAO standards. High content of essential amino acids leucine, valine, phenylalanine and lysine makes algal protein isolate a high quality component of CELSS diets. To optimize the removal of algal lipids and pigments supercritical carbon dioxide extraction (with and without ethanol as a co-solvent) was used. Addition of ethanol to supercritical CO2 resulted in more efficient removal of algal lipids and produced protein isolate with a good yield and protein recovery. The protein isolate extracted by the above mixture had an improved water solubility.

  3. Harmful Algal Bloom-Associated Illness Surveillance: Lessons From Reported Hospital Visits in New York, 2008-2014.

    PubMed

    Figgatt, Mary; Muscatiello, Neil; Wilson, Lloyd; Dziewulski, David

    2016-03-01

    We identified hospital visits with reported exposure to harmful algal blooms, an emerging public health concern because of toxicity and increased incidence. We used the World Health Organization's International Classification of Disease (ICD) medical code specifying environmental exposure to harmful algal blooms to extract hospital visit records in New York State from 2008 to 2014. Using the ICD code, we identified 228 hospital visits with reported exposure to harmful algal blooms. They occurred all year long and had multiple principal diagnoses. Of all hospital visits, 94.7% were managed in the emergency department and 5.3% were hospitalizations. As harmful algal bloom surveillance increases, the ICD code will be a beneficial tool to public health only if used properly. PMID:26794161

  4. Assessment of factors limiting algal growth in acidic pit lakes-a case study from Western Australia, Australia.

    PubMed

    Kumar, R Naresh; McCullough, Clint D; Lund, Mark A; Larranaga, Santiago A

    2016-03-01

    Open-cut mining operations can form pit lakes on mine closure. These new water bodies typically have low nutrient concentrations and may have acidic and metal-contaminated waters from acid mine drainage (AMD) causing low algal biomass and algal biodiversity. A preliminary study was carried out on an acidic coal pit lake, Lake Kepwari, in Western Australia to determine which factors limited algal biomass. Water quality was monitored to obtain baseline data. pH ranged between 3.7 and 4.1, and solute concentrations were slightly elevated to levels of brackish water. Concentrations of N were highly relative to natural lakes, although concentrations of FRP (<0.01 mg/L) and C (total C 0.7-3.7 and DOC 0.7-3.5 mg/L) were very low, and as a result, algal growth was also extremely low. Microcosm experiment was conducted to test the hypothesis that nutrient enrichment will be able to stimulate algal growth regardless of water quality. Microcosms of Lake Kepwari water were amended with N, P and C nutrients with and without sediment. Nutrient amendments under microcosm conditions could not show any significant phytoplankton growth but was able to promote benthic algal growth. P amendments without sediment showed a statistically higher mean algal biomass concentration than controls or microcosms amended with phosphorus but with sediment did. Results indicated that algal biomass in acidic pit lake (Lake Kepwari) may be limited primarily by low nutrient concentrations (especially phosphorus) and not by low pH or elevated metal concentrations. Furthermore, sediment processes may also reduce the nutrient availability. PMID:26593729

  5. Evaluation of nutritive value and in vitro rumen fermentation gas accumulation of de-oiled algal residues

    PubMed Central

    2014-01-01

    Background Algae are widely recognized for their high oil content and for exponentially accumulating biomass with particular potential to provide single cell protein for human consumption or animal feed. It is believed that along with biodiesel from algae, the high protein de-oiled algal residue may become an alternative feed supplement option in the future. This study was conducted to investigate de-oiled algal residue obtained from the common Chlorella species, Thalassiosira weissflogii, Selenarstrum capricornutum, Scenedesmus sp., and Scenedesmus dimorphus for assessment as potential feed supplements for ruminants by comparing with soybean (Glycine max) meal and alfalfa (Medicago sativa) hay. Results With the exception of T. weissflogii, algal residue had higher concentrations of Cu, Zn, and Mn and lower concentration of Ca, Mg, and K than soybean meal and alfalfa hay. The algal residue CP (crude protein) concentrations ranged from 140 to 445 g/kg DM and varied among the de-oiled residues. In vitro rumen fermentation gas accumulation curves indicated that algal biomass degradation potential was less than that of soybean meal or alfalfa hay by up to 41.7%. The gas production curve, interpreted with a dual pool logistic model, confirmed that the fraction sizes for fast fermenting and slow fermenting of de-oiled algal residues were smaller than those in soybean meal and alfalfa hay, and the fermenting rate of the fractions was also low. Conclusions Inferior in vitro rumen gas accumulation from the five de-oiled algal residues suggests that these algal byproducts are less degradable in the rumen. PMID:25093078

  6. Changes in soil algal communities in spruce phytocenoses under the influence of aerotechnogenic pollution

    NASA Astrophysics Data System (ADS)

    Novakovskaya, I. V.; Patova, E. N.

    2007-05-01

    The regularities of the development of algal communities in podzolic soils under coniferous forests were studied in areas differing in their technogenic pollution intensity. In the unpolluted soils under spruce forests, 80 alga species of 6 divisions were found; in the soils under the coniferous forests located in the zone exposed to the technogenic pollution, 59 alga species of 5 divisions were found. The algal groups in the soils of the spruce forests included 14 48 taxa. Chlamydomonas gloeogama, C. reinhardtii, Chlorella vulgaris, Klebsormidium nitens, and Stichococcus bacillaris were resistant to different anthropogenic impacts. The results obtained may be used for monitoring of the state of the soil biota in the soils under the boreal forests of protected areas and also in spruce forests exposed to intense aerial technogenic pollution.

  7. Harmful algal blooms and climate change: Learning from the past and present to forecast the future

    PubMed Central

    Wells, Mark L.; Trainer, Vera L.; Smayda, Theodore J.; Karlson, Bengt S.O.; Trick, Charles G.; Kudela, Raphael M.; Ishikawa, Akira; Bernard, Stewart; Wulff, Angela; Anderson, Donald M.; Cochlan, William P.

    2015-01-01

    Climate change pressures will influence marine planktonic systems globally, and it is conceivable that harmful algal blooms may increase in frequency and severity. These pressures will be manifest as alterations in temperature, stratification, light, ocean acidification, precipitation-induced nutrient inputs, and grazing, but absence of fundamental knowledge of the mechanisms driving harmful algal blooms frustrates most hope of forecasting their future prevalence. Summarized here is the consensus of a recent workshop held to address what currently is known and not known about the environmental conditions that favor initiation and maintenance of harmful algal blooms. There is expectation that harmful algal bloom (HAB) geographical domains should expand in some cases, as will seasonal windows of opportunity for harmful algal blooms at higher latitudes. Nonetheless there is only basic information to speculate upon which regions or habitats HAB species may be the most resilient or susceptible. Moreover, current research strategies are not well suited to inform these fundamental linkages. There is a critical absence of tenable hypotheses for how climate pressures mechanistically affect HAB species, and the lack of uniform experimental protocols limits the quantitative cross-investigation comparisons essential to advancement. A HAB “best practices” manual would help foster more uniform research strategies and protocols, and selection of a small target list of model HAB species or isolates for study would greatly promote the accumulation of knowledge. Despite the need to focus on keystone species, more studies need to address strain variability within species, their responses under multifactorial conditions, and the retrospective analyses of long-term plankton and cyst core data; research topics that are departures from the norm. Examples of some fundamental unknowns include how larger and more frequent extreme weather events may break down natural biogeographic

  8. An Energy-limited Model of Algal Biofuels Production: Towards the Next Generation of Advanced Biofuels

    DOE PAGESBeta

    Dunlop, Eric

    2013-01-01

    Algal biofuels are increasingly important as a source of renewable energy. The absence of reliable thermodynamic and other property data, and the large amount of kinetic data that would normally be required have created a major barrier to simulation. Additionally, the absence of a generally accepted flowsheet for biofuel production means that detailed simulation of the wrong approach is a real possibility. This model of algal biofuel production estimates the necessary data and places it into a heuristic model using a commercial simulator that back-calculates the process structure required. Furthermore, complex kinetics can be obviated for now by putting themore » simulator into energy limitation and forcing it to solve for the missing design variables, such as bioreactor surface area, productivity, and oil content. The model does not attempt to prescribe a particular approach, but provides a guide towards a sound engineering approach to this challenging and important problem.« less

  9. Spectral modeling for the identification and quantification of algal blooms: A test of approach

    SciTech Connect

    Malthus, T.J.; Grieve, L.; Harwar, M.D.

    1997-06-01

    The aim of this paper is to develop and test a Monte Carlo modelling approach for the characterization of reflectance for different bloom-forming marine phytoplankton species. The model was tested on optical data for four species (Dunaliella salina, Pavlova pinguis, Emiliania huxleyi and Synechocystes spp.) and simulations performed over a range of chlorophyll concentrations. Discriminant analysis identified 10 key wavelengths which could be used to maximize the separation between the four species. The resulting wavelengths were combined in a neural network to show 100% accuracy in classifying species type. Further simulations were undertaken to investigate the effect of aquatic humus on reflectance characteristics and the change in wavelengths for algal discrimination. The implications for the development of algorithms for the identification of algal bloom species type by remote sensing are briefly discussed.

  10. Potential utilization of algal protein concentrate as a food ingredient in space habitats

    NASA Technical Reports Server (NTRS)

    Nakhost, Z.; Karel, M.

    1989-01-01

    Green alga Scenedesmus obliquus was studied as one of the potential sources of macronutrients in a space habitat. Algal protein concentrate (70.5% protein) was incorporated into a variety of food products such as bran muffins, fettuccine (spinach noodle imitation) and chocolate chip cookies. Food products containing 20 to 40% of incorporated algal proteins were considered. In the sensory analysis the greenish color of the bran muffins and cookies was not found to be objectional. The mild spinachy flavor (algae flavor) was less detectable in chocolate chip cookies than in bran muffins. The color and taste of the algae noodles were found to be pleasant and compared well with commercially available spinach noodles. Commercially available spray-dried Spirulina algae was also incorporated so the products can be compared with those containing Scenedesmus obliquus concentrate. Food products containing commercial algae had a dark green color and a "burnt after taste" and were less acceptable to the panelists.

  11. An Energy-limited Model of Algal Biofuels Production: Towards the Next Generation of Advanced Biofuels

    SciTech Connect

    Dunlop, Eric

    2013-01-01

    Algal biofuels are increasingly important as a source of renewable energy. The absence of reliable thermodynamic and other property data, and the large amount of kinetic data that would normally be required have created a major barrier to simulation. Additionally, the absence of a generally accepted flowsheet for biofuel production means that detailed simulation of the wrong approach is a real possibility. This model of algal biofuel production estimates the necessary data and places it into a heuristic model using a commercial simulator that back-calculates the process structure required. Furthermore, complex kinetics can be obviated for now by putting the simulator into energy limitation and forcing it to solve for the missing design variables, such as bioreactor surface area, productivity, and oil content. The model does not attempt to prescribe a particular approach, but provides a guide towards a sound engineering approach to this challenging and important problem.

  12. Disk Diffusion Assay to Assess the Antimicrobial Activity of Marine Algal Extracts.

    PubMed

    Desbois, Andrew P; Smith, Valerie J

    2015-01-01

    Marine algae are a relatively untapped source of bioactive natural products, including those with antimicrobial activities. The ability to assess the antimicrobial activity of cell extracts derived from algal cultures is vital to identifying species that may produce useful novel antibiotics. One assay that is used widely for this purpose is the disk diffusion assay due to its simplicity, rapidity, and low cost. Moreover, this assay gives output data that are easy to interpret and can be used to screen many samples at once irrespective of the solvent used during preparation. In this chapter, a step-by-step protocol for performing a disk diffusion assay is described. The assay is particularly well suited to testing algal cell extracts and fractions resulting from separation through bioassay-guided approaches. PMID:26108520

  13. Photosynthetic pigments as indicators of algal activity in the Upper Potomac Estuary

    NASA Astrophysics Data System (ADS)

    Sze, P.

    1981-10-01

    The Potomac River was monitored at Key Bridge from May - September, 1981. Temperature, major nutrients, photosynthetic pigments, abundance of major groups of photoplankton (direct counts), and potential photosynthetic production (oxygen method) were measured weekly in surface samples collected near mid-river. Chlorophyll A showed the same general trends as the cell counts and production with greatest algal activity in late May and August and a minimum in June. Centric diatoms and chlorococcalean green algae were the major planktonic algae in 1981, as in previous years. Overall, the activity of photoplankton did not show any significant change from previous years, and there was no evidence for prolonged nutrient depletion as a result of algal activity in the river.

  14. Polyurethane and alginate immobilized algal biomass for the removal of aqueous toxic metals

    SciTech Connect

    Fry, I.V.; Mehlhorn, R.J.

    1992-12-01

    We describe the development of immobilized, processed algal biomass for use as an adsorptive filter in the removal of toxic metals from waste water. To fabricate an adsorptive filter from precessed biomass several crucial criteria must be met, including: (1) high metal binding capacity, (2) long term stability (both mechanical and chemical), (3) selectivity for metals of concern (with regard to ionic competition), (4) acceptable flow capacity (to handle large volumes in short time frames), (5) stripping/regeneration (to recycle the adsorptive filter and concentrate the toxic metals to manageable volumes). This report documents experiments with processed algal biomass (Spirulina platensis and Spirulina maxima) immobilized in either alginate gel or preformed polyurethane foam. The adsorptive characteristics of these filters were assessed with regard to the criteria listed above.

  15. Saline wastewater treatment by Chlorella vulgaris with simultaneous algal lipid accumulation triggered by nitrate deficiency.

    PubMed

    Shen, Qiao-Hui; Gong, Yu-Peng; Fang, Wen-Zhe; Bi, Zi-Cheng; Cheng, Li-Hua; Xu, Xin-Hua; Chen, Huan-Lin

    2015-10-01

    Chlorella vulgaris, a marine microalgae strain adaptable to 0-50 g L(-1) of salinity, was selected for studying the coupling system of saline wastewater treatment and lipid accumulation. The effect of total nitrogen (T N) concentration was investigated on algal growth, nutrients removal as well as lipid accumulation. The removal efficiencies of TN and total phosphorus (TP) were found to be 92.2-96.6% and over 99%, respectively, after a batch cultivation of 20 days. To illustrate the response of lipid accumulation to nutrients removal, C. vulgaris was further cultivated in the recycling experiment of tidal saline water within the photobioreactor. The lipid accumulation was triggered upon the almost depletion of nitrate (<5 mg L(-1)), till the final highest lipid content of 40%. The nitrogen conversion in the sequence of nitrate, nitrite, and then to ammonium in the effluents was finally integrated with previous discussions on metabolic pathways of algal cell under nitrogen deficiency. PMID:26117237

  16. Bioengineering aspects of inorganic carbon supply to mass algal cultures. Final report

    SciTech Connect

    Goldman, J.C.

    1980-06-01

    The work included in this report is part of an ongoing study (currently funded by the Solar Energy Research Institute - Subcontract No. XR-9-8144-1) on the inorganic carbon requirements of microalgae under mass culture conditions and covers the period June 1, 1978 through May 31, 1979. It is divided into two parts appended herein. The first part is a literature review on the inorganic carbon chemical system in relation to algal growth requirements, and the second part deals with the kinetics of inorganic carbon-limited growth of two freshwater chlorophytes including the effect of carbon limitation on cellular chemical composition. Additional experiment research covered under this contract was reported in the Proceedings of the 3rd Annual Biomass Energy Systems Conferences, pp. 25-32, Bioengineering aspects of inorganic carbon supply to mass algal cultures. Report No. SERI/TP-33-285.

  17. Direct extraction of photosynthetic electrons from single algal cells by nanoprobing system.

    PubMed

    Ryu, WonHyoung; Bai, Seoung-Jai; Park, Joong Sun; Huang, Zubin; Moseley, Jeffrey; Fabian, Tibor; Fasching, Rainer J; Grossman, Arthur R; Prinz, Fritz B

    2010-04-14

    There are numerous sources of bioenergy that are generated by photosynthetic processes, for example, lipids, alcohols, hydrogen, and polysaccharides. However, generally only a small fraction of solar energy absorbed by photosynthetic organisms is converted to a form of energy that can be readily exploited. To more efficiently use the solar energy harvested by photosynthetic organisms, we evaluated the feasibility of generating bioelectricity by directly extracting electrons from the photosynthetic electron transport chain before they are used to fix CO(2) into sugars and polysaccharides. From a living algal cell, Chlamydomonas reinhardtii, photosynthetic electrons (1.2 pA at 6000 mA/m(2)) were directly extracted without a mediator electron carrier by inserting a nanoelectrode into the algal chloroplast and applying an overvoltage. This result may represent an initial step in generating "high efficiency" bioelectricity by directly harvesting high energy photosynthetic electrons. PMID:20201533

  18. Different algal symbionts explain the vertical distribution of dominant reef corals in the eastern Pacific.

    PubMed Central

    Iglesias-Prieto, R.; Beltrán, V. H.; LaJeunesse, T. C.; Reyes-Bonilla, H.; Thomé, P. E.

    2004-01-01

    Symbiotic reef corals occupy the entire photic zone; however, most species have distinct zonation patterns within the light intensity gradient. It is hypothesized that the presence of specific symbionts adapted to different light regimes may determine the vertical distribution of particular hosts. We have tested this hypothesis by genetic and in situ physiological analyses of the algal populations occupying two dominant eastern Pacific corals, over their vertical distribution in the Gulf of California. Our findings indicate that each coral species hosts a distinct algal taxon adapted to a particular light regime. The differential use of light by specific symbiotic dinoflagellates constitutes an important axis for niche diversification and is sufficient to explain the vertical distribution patterns of these two coral species. PMID:15306298

  19. Development and application of a marine sediment porewater toxicity test using algal spores

    SciTech Connect

    Hooten, R.; Carr, R.S.

    1995-12-31

    An acute pore water toxicity test protocol using germination and growth of marine macroalgae as endpoints was developed to indicate the presence of toxic compounds in marine/estuarine and sediment porewater samples. Zoospores collected from Ulva fasciata and U. lactuca were used as test organisms. Preliminary results with sodium dodecyl sulfate (SDS, a reference toxicant) indicate that zoospores germination and growth of embryonic gametophytes are as sensitive as the sea urchin fertilization and embryological development toxicity tests. Algal germination and growth data for copper, mercury and other metals will be presented. The results of tests utilizing this algal assay with sediment pore water from contaminated sediments will be compared with more traditional sediment toxicity test methods.

  20. Algal biofuels from urban wastewaters: maximizing biomass yield using nutrients recycled from hydrothermal processing of biomass.

    PubMed

    Selvaratnam, T; Pegallapati, A K; Reddy, H; Kanapathipillai, N; Nirmalakhandan, N; Deng, S; Lammers, P J

    2015-04-01

    Recent studies have proposed algal cultivation in urban wastewaters for the dual purpose of waste treatment and bioenergy production from the resulting biomass. This study proposes an enhancement to this approach that integrates cultivation of an acidophilic strain, Galdieria sulphuraria 5587.1, in a closed photobioreactor (PBR); hydrothermal liquefaction (HTL) of the wet algal biomass; and recirculation of the nutrient-rich aqueous product (AP) of HTL to the PBR to achieve higher biomass productivity than that could be achieved with raw wastewater. The premise is that recycling nutrients in the AP can maintain optimal C, N and P levels in the PBR to maximize biomass growth to increase energy returns. Growth studies on the test species validated growth on AP derived from HTL at temperatures from 180 to 300°C. Doubling N and P concentrations over normal levels in wastewater resulted in biomass productivity gains of 20-25% while N and P removal rates also doubled. PMID:25704095

  1. Hydraulic retention time effects on wastewater nutrient removal and bioproduct production via rotating algal biofilm reactor.

    PubMed

    Iman Shayan, Sahand; Agblevor, Foster A; Bertin, Lorenzo; Sims, Ronald C

    2016-07-01

    Rotating algal biofilm reactor (RABR) technology was successfully employed in an effective strategy to couple the removal of wastewater nutrients with accumulation of valuable bioproducts by grown algae. A secondary stage municipal wastewater was fed to the developed system and the effects of the hydraulic retention time (HRT) parameter on both nutrient removal and bioproduct production were evaluated under fed-batch operation mode. Two sets of bench scale RABRs were designed and operated with HRTs of 2 and 6days in order to provide competitive environment for algal growth. The HRT significantly affected nitrogen and phosphorus uptakes along with lipid and starch accumulations by microalgae in harvested biofilms. Domination of nitrogen removal in 2-day HRT with higher lipid accumulation (20% on dried weight basis) and phosphorus removal in 6-day HRT with higher starch production (27% on dried weight basis) was observed by comparing the performances of the RABRs in duplicate runs. PMID:27038261

  2. Potential utilization of algal protein concentrate as a food ingredient in space habitats.

    PubMed

    Nakhost, Z; Karel, M

    1989-01-01

    Green alga Scenedesmus obliquus was studied as one of the potential sources of macronutrients in a space habitat. Algal protein concentrate (70.5% protein) was incorporated into a variety of food products such as bran muffins, fettuccine (spinach noodle imitation) and chocolate chip cookies. Food products containing 20 to 40% of incorporated algal proteins were considered. In the sensory analysis the greenish color of the bran muffins and cookies was not found to be objectional. The mild spinachy flavor (algae flavor) was less detectable in chocolate chip cookies than in bran muffins. The color and taste of the algae noodles were found to be pleasant and compared well with commercially available spinach noodles. Commercially available spray-dried Spirulina algae was also incorporated so the products can be compared with those containing Scenedesmus obliquus concentrate. Food products containing commercial algae had a dark green color and a "burnt after taste" and were less acceptable to the panelists. PMID:11538068

  3. Observations on the Occurrence, Distribution, and Seasonal Incidence of Blue-green Algal Viruses

    PubMed Central

    Safferman, Robert S.; Morris, Mary E.

    1967-01-01

    Phycovirus populations were found in 11 of the 12 waste stabilization ponds studied. These populations were comprised solely of blue-green algal (BGA) viruses. Two virus types were observed, one of which was related to the previously reported LPP-1 virus. The incidence and magnitude of the LPP group indicated that several of the ponds supported well-established BGA virus populations of this type. Counts as high as 270 plaque-forming units/ml were noted; however, marked differences in the nature and magnitude of these BGA viruses were apparent even in geographically related ponds of similar design. Of the algal strains found dominant in these ponds, none was of the type reported susceptible to the LPP viruses. PMID:16349731

  4. Complete genome of brown algal polysaccharides-degrading Pseudoalteromonas issachenkonii KCTC 12958(T) (=KMM 3549(T)).

    PubMed

    Lee, Sang-Heon; Choe, Hanna; Kim, Song-Gun; Park, Doo-Sang; Nasir, Arshan; Kim, Byung Kwon; Kim, Kyung Mo

    2016-02-10

    Pseudoalteromonas issachenkonii is a Gram-negative, rod-shaped, flagellated, aerobic, chemoorganotrophic marine bacterium that was isolated from the thallus of Fucus evanescens (marine brown macroalgae) sampled from the Kraternaya Bight of the Kurile Islands in the Pacific Ocean. Here, we report the complete genome of P. issachenkonii KCTC 12958(T) (=KMM 3549(T)=LMG 19697(T)=CIP 106858(T)), which consists of 4,131,541 bp (G+C content of 40.3%) with two chromosomes, 3538 protein-coding genes, 102 tRNAs and 8 rRNA operons. Several genes related to glycoside hydrolases, proteases, and bacteriolytic- and hemolytic activities were detected in the genome that help explain how the strain mediates degradation of algal cell wall and decomposes algal polysaccharides into industrially applicable products. PMID:26732413

  5. Antimicrobial effects of marine algal extracts and cyanobacterial pure compounds against five foodborne pathogens.

    PubMed

    Dussault, Dominic; Vu, Khanh Dang; Vansach, Tifanie; Horgen, F David; Lacroix, Monique

    2016-05-15

    The marine environment is a proven source of structurally complex and biologically active compounds. In this study, the antimicrobial effects of a small collection of marine-derived extracts and isolates, were evaluated against 5 foodborne pathogens using a broth dilution assay. Results demonstrated that algal extracts from Padina and Ulva species and cyanobacterial compounds antillatoxin B, laxaphycins A, B and B3, isomalyngamide A, and malyngamides C, I and J showed antimicrobial activity against Gram positive foodborne pathogens (Listeria monocytogenes, Bacillus cereus and Staphylococcus aureus) at low concentrations (⩽ 500 μg/ml). None of the algal extracts or cyanobacterial isolates had antibacterial activity against Gram negative bacteria (Escherichia coli and Salmonella enterica serovar Typhimurium). PMID:26775951

  6. Ultraviolet radiation dose calculation for algal suspensions using UVA and UVB extinction coefficients.

    PubMed

    Navarro, Enrique; Muñiz, Selene; Korkaric, Muris; Wagner, Bettina; de Cáceres, Miquel; Behra, Renata

    2014-03-01

    Although the biological importance of ultraviolet light (UVR) attenuation has been recognised in marine and freshwater environments, it is not generally considered in in vitro ecotoxicological studies using algal cell suspensions. In this study, UVA and UVB extinction were determined for cultures of algae with varying cell densities, and the data were used to calculate the corresponding extinction coefficients for both UVA and UVB wavelength ranges. Integrating the Beer-Lambert equation to account for changes in the radiation intensity reaching each depth, from the surface until the bottom of the experimental vessel, we obtained the average UVA and UVB intensity to which the cultured algal cells were exposed. We found that UVR intensity measured at the surface of Chlamydomonas reinhardtii cultures lead to a overestimation of the UVR dose received by the algae by 2-40 times. The approach used in this study allowed for a more accurate estimation of UVA and UVB doses. PMID:24607609

  7. The Effect of Algal Symbionts on the Accuracy of Sr/Ca Paleotemperatures from Coral

    NASA Astrophysics Data System (ADS)

    Cohen, Anne L.; Owens, Kathryn E.; Layne, Graham D.; Shimizu, Nobumichi

    2002-04-01

    The strontium-to-calcium ratio (Sr/Ca) of reef coral skeleton is commonly used as a paleothermometer to estimate sea surface temperatures (SSTs) at crucial times in Earth's climate history. However, these estimates are disputed, because uptake of Sr into coral skeleton is thought to be affected by algal symbionts (zooxanthellae) living in the host tissue. Here, we show that significant distortion of the Sr/Ca temperature record in coral skeleton occurs in the presence of algal symbionts. Seasonally resolved Sr/Ca in coral without symbionts reflects local SSTs with a temperature sensitivity equivalent to that of laboratory aragonite precipitated at equilibrium and the nighttime skeletal deposits of symbiotic reef corals. However, up to 65% of the Sr/Ca variability in symbiotic skeleton is related to symbiont activity and does not reflect water temperature.

  8. Change in Photosystem II Photochemistry During Algal Growth Phases of Chlorella vulgaris and Scenedesmus obliquus.

    PubMed

    Oukarroum, Abdallah

    2016-06-01

    Sensitivity of photosynthetic processes towards environmental stress is used as a bioanalytical tool to evaluate the responses of aquatic plants to a changing environment. In this paper, change of biomass density, chlorophyll a fluorescence and photosynthetic parameters during growth phases of two microalgae Chlorella vulgaris and Scenedesmus obliquus were studied. The photosynthetic growth behaviour changed significantly with cell age and algae species. During the exponential phase of growth, the photosynthesis capacity reached its maximum and decreased in ageing algal culture during stationary phase. In conclusion, the chlorophyll a fluorescence OJIP method and the derived fluorescence parameters would be an accurate method for obtaining information on maximum photosynthetic capacities and monitoring algal cell growth. This will contribute to more understanding, for example, of toxic actions of pollutants in microalgae test. PMID:26868257

  9. Observations on the Occurrence, Distribution, and Seasonal Incidence of Blue-green Algal Viruses.

    PubMed

    Safferman, R S; Morris, M E

    1967-09-01

    Phycovirus populations were found in 11 of the 12 waste stabilization ponds studied. These populations were comprised solely of blue-green algal (BGA) viruses. Two virus types were observed, one of which was related to the previously reported LPP-1 virus. The incidence and magnitude of the LPP group indicated that several of the ponds supported well-established BGA virus populations of this type. Counts as high as 270 plaque-forming units/ml were noted; however, marked differences in the nature and magnitude of these BGA viruses were apparent even in geographically related ponds of similar design. Of the algal strains found dominant in these ponds, none was of the type reported susceptible to the LPP viruses. PMID:16349731

  10. Metabolic network reconstruction of Chlamydomonas offers insight into light-driven algal metabolism

    PubMed Central

    Chang, Roger L; Ghamsari, Lila; Manichaikul, Ani; Hom, Erik F Y; Balaji, Santhanam; Fu, Weiqi; Shen, Yun; Hao, Tong; Palsson, Bernhard Ø; Salehi-Ashtiani, Kourosh; Papin, Jason A

    2011-01-01

    Metabolic network reconstruction encompasses existing knowledge about an organism's metabolism and genome annotation, providing a platform for omics data analysis and phenotype prediction. The model alga Chlamydomonas reinhardtii is employed to study diverse biological processes from photosynthesis to phototaxis. Recent heightened interest in this species results from an international movement to develop algal biofuels. Integrating biological and optical data, we reconstructed a genome-scale metabolic network for this alga and devised a novel light-modeling approach that enables quantitative growth prediction for a given light source, resolving wavelength and photon flux. We experimentally verified transcripts accounted for in the network and physiologically validated model function through simulation and generation of new experimental growth data, providing high confidence in network contents and predictive applications. The network offers insight into algal metabolism and potential for genetic engineering and efficient light source design, a pioneering resource for studying light-driven metabolism and quantitative systems biology. PMID:21811229

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

    USGS Publications Warehouse

    Harris, Theodore D.; Graham, Jennifer

    2015-01-01

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

  12. Dewatering as a non-toxic control of nuisance midge larvae in algal wastewater treatment floways.

    PubMed

    Keller, Troy A; Husted, Emily M

    2015-01-01

    Attached-algae floways have tremendous potential for use in wastewater treatment because natural algal communities show high nutrient removal efficiencies, have low operating costs, and are easy to maintain. Algal wastewater floways may also serve as a sustainable option for producing renewable energy because algae grow rapidly, are easily harvested, and can serve as a source of biomass for biofuel. However, pests such as chironomids (Diptera) colonize open channel periphyton floways and their larvae damage the biofilms. While pesticides can control midge larvae, little information is known about alternative, non-toxic controls. This study examined the effectiveness of periodic, short-term dewatering (4 hours every 9 days) on midge abundance and periphyton growth in 16 recirculating, outdoor floways (3 m long, 0.1 m wide). We compared midge abundance and algal accumulation (chlorophyll a, b, c, and pheophytin) among control (n=8) and dewatered (n=8) floways filled with secondarily treated wastewater (27 days, 10 hours of daylight). Dewatered flumes had 42% fewer midges and 28-49% lower algal productivity (as measured by chlorophyll a, b, c, and pheophytin pigments). Chlorophyll a production rates averaged (±1 SD) 0.5±0.2 μg/cm2/day in control floways compared to 0.3±0.1 μg/cm2/day dewatered floways. Short-term dewatering effectively reduced midges but also damaged periphyton. To maximize the recovery of periphyton biomass, operators should harvest periphyton from floways during dewatering events before periphyton is damaged by desiccation or direct exposure to sunlight. PMID:25607663

  13. Production of algal-based biofuel using non-fresh water sources.

    SciTech Connect

    Sun, Amy Cha-Tien; Reno, Marissa Devan

    2007-09-01

    The goal of this LDRD involves development of a system dynamics model to understand the interdependencies between water resource availability and water needs for production of biofuels. Specifically, this model focuses on availability and feasibility of non-traditional water sources from dairy wastewater, produced water from crude oil production and from coal-bed methane gas extraction for the production of algal-based biofuel. The conceptual simulation framework and historical data are based on two locales within New Mexico, the San Juan basin in the northwest and the Permian basin in the southeast, where oil and gas drilling have increased considerably in the last ten years. The overall water balance ignores both transportation options and water chemistry and is broken down by county level. The resulting model contains an algal growth module, a dairy module, an oil production module, and a gas production module. A user interface is also created for controlling the adjustable parameters in the model. Our preliminary investigation indicates a cyclical demand for non-fresh water due to the cyclical nature of algal biomass production and crop evapotranspiration. The wastewater from the dairy industry is not a feasible non-fresh water source because the agricultural water demand for cow's dry feed far exceeds the amount generated at the dairy. The uncertainty associated with the water demand for cow's dry matter intake is the greatest in this model. The oil- and gas-produced water, ignoring the quality, provides ample supply for water demand in algal biomass production. There remains work to address technical challenges associated with coupling the appropriate non-fresh water source to the local demand.

  14. Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass.

    PubMed

    O'Neil, Gregory W; Williams, John R; Wilson-Peltier, Julia; Knothe, Gerhard; Reddy, Christopher M

    2016-01-01

    The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. Biomass-derived biofuels have gained considerable attention in this regard, however first generation biofuels from edible crops like corn ethanol or soybean biodiesel have generally fallen out of favor. There is thus great interest in the development of methods for the production of liquid fuels from domestic and superior non-edible sources. Here we describe a detailed procedure for the production of a purified biodiesel from the marine microalgae Isochrysis. Additionally, a unique suite of lipids known as polyunsaturated long-chain alkenones are isolated in parallel as potentially valuable coproducts to offset the cost of biodiesel production. Multi-kilogram quantities of Isochrysis are purchased from two commercial sources, one as a wet paste (80% water) that is first dried prior to processing, and the other a dry milled powder (95% dry). Lipids are extracted with hexanes in a Soxhlet apparatus to produce an algal oil ("hexane algal oil") containing both traditional fats (i.e., triglycerides, 46-60% w/w) and alkenones (16-25% w/w). Saponification of the triglycerides in the algal oil allows for separation of the resulting free fatty acids (FFAs) from alkenone-containing neutral lipids. FFAs are then converted to biodiesel (i.e., fatty acid methyl esters, FAMEs) by acid-catalyzed esterification while alkenones are isolated and purified from the neutral lipids by crystallization. We demonstrate that biodiesel from both commercial Isochrysis biomasses have similar but not identical FAME profiles, characterized by elevated polyunsaturated fatty acid contents (approximately 40% w/w). Yields of biodiesel were consistently higher when starting from the Isochrysis wet paste (12% w/w vs. 7% w/w), which can be traced to lower amounts of hexane algal oil obtained from the powdered Isochrysis product. PMID:27404113

  15. Effects of algal food quality on sexual reproduction of Daphnia magna.

    PubMed

    Choi, Jong-Yun; Kim, Seong-Ki; La, Geung-Hwan; Chang, Kwang-Hyeon; Kim, Dong-Kyun; Jeong, Keon-Young; Park, Min S; Joo, Gea-Jae; Kim, Hyun-Woo; Jeong, Kwang-Seuk

    2016-05-01

    The objective of our study was to investigate sexual reproduction of Daphnia magna associated with mating behaviors and hatching rates, according to different algal food sources. Since a diatom is known to contain more abundant long-chain poly unsaturated fatty acids (PUFAs), we hypothesized that the diatom-consuming D. magna would exhibit more successful reproduction rates. Upon the hypothesis, we designed three experiments using two algal species, a green alga (Chlorella vulgaris) and a diatom (Stephanodiscus hantzschii). From the results, we found that the mating frequency and copulation duration increased in the treatment with S. hantzschii, resulting in a significant increase of hatching rates of resting eggs. In the other two repetitive mating strategies (e.g., one female vs. multiple males, and one male vs. multiple females), we found that the hatching rates of resting eggs were greater in the S. hantzschii treatment. In addition to the mating strategy, male body size significantly increased in the diatom treatment, hence average diameter of penis was also statistically different among the treatments (greater diameter in the S. hantzschii treatment). To examine the effect of algal food quality, we estimated quantity of fatty acids in the two algal species. Our result showed that S. hantzschii had a higher proportion of long-chain PUFAs than C. vulgaris. Furthermore, a stable isotope analysis revealed that carbon and nitrogen originated from S. hantzschii were more assimilated to D. magna. In summary, our study manifested that diatom consumption of D. magna leads to more successful sexual reproduction. We then discussed how the diatom consumption of zooplankton influences food web dynamics in a freshwater ecosystem. PMID:27217941

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

    PubMed

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

    2012-11-01

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

  17. Effects of changing continuous iron input rates on a Southern Ocean algal assemblage

    NASA Astrophysics Data System (ADS)

    Hare, C. E.; DiTullio, G. R.; Riseman, S. F.; Crossley, A. C.; Popels, L. C.; Sedwick, P. N.; Hutchins, D. A.

    2007-05-01

    The upwelling of nutrients and iron (Fe) sustains biological production in much of the Southern Ocean. Using a shipboard natural community continuous culture system (Ecostat), we supplied a single added Fe concentration at two dilution rates chosen to examine the effects of variations in realistic growth and loss rates on an Fe-limited algal community in the Antarctic Zone south of Australia. A parallel growout experiment provided "no-dilution" +Fe and -Fe controls. In the continuous flow experiment, phytoplankton biomass was lower and more constant throughout the incubation and major nutrients were never depleted. Nanophytoplankton abundance remained similar in both growout treatments, and therefore, growth of this group did not appear to be Fe-limited. The addition of Fe in a continuous fashion resulted in a community co-dominated by both small diatoms and nanophytoplankton. Increases in dilution rate favored diatom species that were smaller and faster-growing, as well as non-silicified algal groups. Particulate carbon (PC) to particulate nitrogen (PN) ratios increased above the Redfield ratio when Fe was added in a continuous fashion, while biogenic silica (BSi) to PC and PN ratios decreased 2-3 fold in the continuous flow experiment compared to the initial conditions and the parallel growout control experiment. Photosynthetic efficiency increased in the continuous flow treatments above the control but remained significantly lower than in the 1.4 nM Fe addition. The results of our shipboard continuous flow experiments are compared and contrasted with those of the mesoscale Southern Ocean Iron RElease Experiment (SOIREE) carried out at the same site. Our results suggest that increases in natural dilution rates (i.e. vertical turbulent diffusion) in polar Antarctic waters could shift the algal community towards smaller, faster-growing algal species, thus having a major effect on nutrient cycling and carbon export in the Southern Ocean.

  18. An algal carbon budget for pelagic-benthic coupling in Lake Michigan

    USGS Publications Warehouse

    Fitzgerald, S.A.; Gardner, W.S.

    1993-01-01

    Assimilation and respiration rates of Diporeia sp., an abundant benthic amphipod, and of sediment microheterotrophs were measured in a microcosm study. Release of radioisotope in the form of dissolved organic compounds was much lower than that incorporated and respired for both Diporeia and sediment bacteria. Of the 61 mmol C m-2 of algal C estimated to be deposited during the spring bloom. -from Authors

  19. Degradation of algal lipids by deep-sea benthic foraminifera: An in situ tracer experiment

    NASA Astrophysics Data System (ADS)

    Nomaki, Hidetaka; Ohkouchi, Naohiko; Heinz, Petra; Suga, Hisami; Chikaraishi, Yoshito; Ogawa, Nanako O.; Matsumoto, Kouhei; Kitazato, Hiroshi

    2009-09-01

    We conducted an in situ feeding experiment using 13C-labeled unicellular algae in Sagami Bay, Japan (water depth, 1450 m), in order to understand the fate of lipid compounds in phytodetritus at the deep-sea floor. We examined the incorporation of excess 13C into lipid compounds extracted from bulk sediments and benthic foraminiferal cells. 13C-enriched fatty acids derived from 13C-labeled algae were exponentially degraded during 6 days of incubation in the sediment. Subsequent enrichments in 13C in sedimentary n-C 15,anteiso-C 17, and C 17 fatty acids indicated the microbial degradation of algal material and production of bacterial biomass in the sediment. We observed the incorporation of 13C-labeled algal phytol and fatty acids into foraminiferal cells. The compositions of 13C-labeled algal lipids in foraminiferal cells were different from those in the bulk sediments, indicating that foraminiferal feeding and digestion influenced the lipid distribution in the sediments. Furthermore, some sterols in Globobulimina affinis (e.g., 24-ethylcholesta-5,22-dien-3β-ol, 24-ethylcholest-5-en-3β-ol, and 23,24-dimethylcholesta-5,22E-dien-3β-ol) were newly produced via the modification of dietary algal sterols within 4-6 days. In addition to the effects of bacteria, feeding by benthic foraminifera can result in a significant reorganization of the composition of organic matter and influence benthic food webs and carbon cycling at the deep-sea floor.

  20. Algal blooms and the nitrogen-enrichment hypothesis in Florida springs: evidence, alternatives, and adaptive management.

    PubMed

    Heffernan, James B; Liebowitz, Dina M; Frazer, Thomas K; Evans, Jason M; Cohen, Matthew J

    2010-04-01

    Contradictions between system-specific evidence and broader paradigms to explain ecosystem behavior present a challenge for natural resource management. In Florida (U.S.A.) springs, increasing nitrate (NO3-) concentrations have been implicated as the cause of algal overgrowth via alleviation of N-limitation. As such, policy and management efforts have centered heavily on reduction of nitrogen (N) loads. While the N-limitation hypothesis appears well founded on broadly supported aquatic eutrophication models, several observations from Florida springs are inconsistent with this hypothesis in its present simplified form. First, NO3- concentration is not correlated with algal abundance across the broad population of springs and is weakly negatively correlated with primary productivity. Second, within individual spring runs, algal mats are largely confined to the headwater reaches within 250 m of spring vents, while elevated NO3- concentrations persist for several kilometers or more. Third, historic observations suggest that establishment of macroalgal mats often lags behind observed increases in NO3- by more than a decade. Fourth, although microcosm experiments indicate high thresholds for N-limitation of algae, experiments in situ have demonstrated only minimal response to N enrichment. These muted responses may reflect large nutrient fluxes in springs, which were sufficient to satisfy present demand even at historic concentrations. New analyses of existing data indicate that dissolved oxygen (DO) has declined dramatically in many Florida springs over the past 30 years, and that DO and grazer abundance are better predictors of algal abundance in springs than are nutrient concentrations. Although a precautionary N-reduction strategy for Florida springs is warranted given demonstrable effects of nutrient enrichment in a broad suite of aquatic systems worldwide, the DO-grazer hypothesis and other potential mechanisms merit increased scientific scrutiny. This case study

  1. Algal Data from Selected Sites in the Upper Colorado River Basin, Colorado, Water Years 1996-97

    USGS Publications Warehouse

    Mize, Scott V.; Deacon, Jeffrey R.

    2001-01-01

    Algal community samples were collected at 15 sites in the Upper Colorado River Basin in Colorado as part of the National Water-Quality Assessment Program during water years 1996-97. Sites sampled were located in two physiographic provinces, the Southern Rocky Mountains and the Colorado Plateaus, and represented agricultural, mining, urban, and mixed land uses and background conditions. Algal samples were collected once per year during low-flow conditions. Quantitative algal samples were collected within two targeted instream habitat types including a taxonomically richest-targeted habitat and a depositional-targeted habitat. This report presents the algal community data collected at the fixed sites in the Upper Colorado River Basin study unit. Algal data include densities (abundance of cells per square centimeter of substrate) and biovolumes (cubic micrometers of cells per square centimeter of substrate) for the two habitat types. Quality-assurance and quality-control results for algal samples indicate that the largest sampling variability tends to occur in samples from small streams.

  2. Biodegradability of algal-derived organic matter in a large artificial lake by using stable isotope tracers.

    PubMed

    Lee, Yeonjung; Lee, Bomi; Hur, Jin; Min, Jun-Oh; Ha, Sun-Yong; Ra, Kongtae; Kim, Kyung-Tae; Shin, Kyung-Hoon

    2016-05-01

    In order to understand the biodegradability of algal-derived organic matter, biodegradation experiments were conducted with (13)C and (15)N-labeled natural phytoplankton and periphytic algal populations in experimental conditions for 60 days. Qualitative changes in the dissolved organic matter were also determined using parallel factor analysis and the stable carbon isotopic composition of the hydrophobic dissolved organic matter through the experimental period. Although algal-derived organic matter is considered to be easily biodegradable, the initial amounts of total organic carbon newly produced by phytoplankton and periphytic algae remained approximately 16 and 44 % after 60 days, respectively, and about 22 and 43 % of newly produced particulate nitrogen remained. Further, the dissolved organic carbon derived from both algal populations increased significantly after 60 days. Although the dissolved organic matter gradually became refractory, the contributions of the algal-derived organic matter to the dissolved organic matter and hydrophobic dissolved organic matter increased. Our laboratory experimental results suggest that algal-derived organic matter produced by phytoplankton and periphytic algae could contribute significantly to the non-biodegradable organic matter through microbial transformations. PMID:26780057

  3. A comparative study on the effect of algal and fish oil on viability and cell proliferation of Caco-2 cells.

    PubMed

    van Beelen, Vincent A; Roeleveld, Johannes; Mooibroek, Hans; Sijtsma, Lolke; Bino, Raoul J; Bosch, Dirk; Rietjens, Ivonne M C M; Alink, Gerrit M

    2007-05-01

    Polyunsaturated fatty acid (PUFA) rich micro-algal oil was tested in vitro and compared with fish oil for antiproliferative properties on cancer cells in vitro. Oils derived from Crypthecodinium cohnii, Schizochytrium sp. and Nitzschia laevis, three commercial algal oil capsules, and menhaden fish oil were used in cell viability and proliferation tests with human colon adenocarcinoma Caco-2 cells. With these tests no difference was found between algal oil and fish oil. The nonhydrolysed algal oils and fish oil showed a much lower toxic effect on cell viability, and cell proliferation in Caco-2 cells than the hydrolysed oils and the free fatty acids (FFAs). Eicosapentaenoic acid (EPA; C20:5n-3) and docosahexaenoic acid (DHA; C22:6n-3) were used as samples for comparison with the tested hydrolysed and nonhydrolysed oils. The hydrolysed samples showed comparative toxicity as the free fatty acids and no difference between algal and fish oil. Oxidative stress was shown to play a role in the antiproliferative properties of EPA and DHA, as alpha-tocopherol could partially reverse the EPA/DHA-induced effects. The results of the present study support a similar mode of action of algal oil and fish oil on cancer cells in vitro, in spite of their different PUFA content. PMID:17141934

  4. Implications of nutrient removal and biomass production by native and augmented algal populations at a municipal wastewater treatment plant.

    PubMed

    Drexler, Ivy L C; Bekaan, Sascha; Eskandari, Yasmin; Yeh, Daniel H

    2014-01-01

    Algal monocultures (Chlorella sorokiniana and Botryococcus braunii) and algal communities native to clarifiers of a wastewater treatment plant were batch cultivated in (1) clarified effluent following a biochemical oxygen demand (BOD) removal reactor post-BOD removal clarified effluent (PBCE), (2) clarified effluent following a nitrification reactor post-nitrification clarified effluent (PNCE), and (3) a reference media (RM). After 12 days, all algal species achieved nitrogen removal between 68 and 82% in PBCE and 37 and 99% in PNCE, and phosphorus removal between 91 and 100% in PBCE and 60 and 100% in PNCE. The pH of the wastewater samples increased above 9.8 after cultivation of each species, which likely aided ammonia volatilization and phosphorus adsorption. Both monocultures grew readily with wastewater as a feedstock, but B. braunii experienced significant crowding from endemic fauna. In most cases, native algal species' nutrient removal efficiency was competitive with augmented algal monocultures, and in some cases achieved a higher biomass yield, demonstrating the potential to utilize native species for nutrient polishing and algal biomass production. PMID:25325538

  5. European phylogeography of the epiphytic lichen fungus Lobaria pulmonaria and its green algal symbiont.

    PubMed

    Widmer, Ivo; Dal Grande, Francesco; Excoffier, Laurent; Holderegger, Rolf; Keller, Christine; Mikryukov, Vladimir S; Scheidegger, Christoph

    2012-12-01

    In lichen symbiosis, fungal and algal partners form close associations, often codispersed by vegetative propagules. Due to the particular interdependence, processes such as colonization, dispersal or genetic drift are expected to result in congruent patterns of genetic structure in the symbionts. To study the population structure of an obligate symbiotic system in Europe, we genotyped the fungal and algal symbionts of the epiphytic lichen Lobaria pulmonaria at eight and seven microsatellite loci, respectively, and analysed about 4300 L. pulmonaria thalli from 142 populations from the species' European distribution range. Based on a centroid approach, which localizes centres of genetic differentiation with a high frequency of geographically restricted alleles, we identified the South Italy-Balkan region as the primary glacial refugial area of the lichen symbiosis. Procrustean rotation analysis and a distance congruence test between the fungal and algal population graphs indicated general concordance between the phylogeographies of the symbionts. The incongruent patterns found in areas of postglacial recolonization may show the presence of an additional refugial area for the fungal symbiont, and the impact that horizontal photobiont transmission and different mutation rates of the symbionts have on their genotypic associations at a continental scale. PMID:23094600

  6. Process for selection of oxygen-tolerant algal mutants that produce H{sub 2}

    DOEpatents

    Ghirardi, M.L.; Seibert, M.

    1999-02-16

    A process for selection of oxygen-tolerant, H{sub 2}-producing algal mutant cells comprises: (a) growing algal cells photoautotrophically under fluorescent light to mid log phase; (b) inducing algal cells grown photoautotrophically under fluorescent light to mid log phase in step (a) anaerobically by (1) resuspending the cells in a buffer solution and making said suspension anaerobic with an inert gas and (2) incubating the suspension in the absence of light at ambient temperature; (c) treating the cells from step (b) with metronidazole, sodium azide, and added oxygen to controlled concentrations in the presence of white light; (d) washing off metronidazole and sodium azide to obtain final cell suspension; (e) plating said final cell suspension on a minimal medium and incubating in light at a temperature sufficient to enable colonies to appear; (f) counting the number of colonies to determine the percent of mutant survivors; and (g) testing survivors to identify oxygen-tolerant H{sub 2}-producing mutants. 5 figs.

  7. First-principles flocculation as the key to low energy algal biofuels processing.

    SciTech Connect

    Hewson, John C.; Wyatt, Nicholas B.; Pierce, Flint; Brady, Patrick Vane; Dwyer, Brian P.; Grillet, Anne Mary; Hankins, Matthew G; Hughes, Lindsey Gloe; Lechman, Jeremy B.; Mondy, Lisa Ann; Murton, Jaclyn K.; O'Hern, Timothy J; Parchert, Kylea Joy; Pohl, Phillip Isabio; Williams, Cecelia Victoria; Zhang, Xuezhi; Hu, Qiang; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton

    2012-09-01

    This document summarizes a three year Laboratory Directed Research and Development (LDRD) program effort to improve our understanding of algal flocculation with a key to overcoming harvesting as a techno-economic barrier to algal biofuels. Flocculation is limited by the concentrations of deprotonated functional groups on the algal cell surface. Favorable charged groups on the surfaces of precipitates that form in solution and the interaction of both with ions in the water can favor flocculation. Measurements of algae cell-surface functional groups are reported and related to the quantity of flocculant required. Deprotonation of surface groups and complexation of surface groups with ions from the growth media are predicted in the context of PHREEQC. The understanding of surface chemistry is linked to boundaries of effective flocculation. We show that the phase-space of effective flocculation can be expanded by more frequent alga-alga or floc-floc collisions. The collision frequency is dependent on the floc structure, described in the fractal sense. The fractal floc structure is shown to depend on the rate of shear mixing. We present both experimental measurements of the floc structure variation and simulations using LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator). Both show a densification of the flocs with increasing shear. The LAMMPS results show a combined change in the fractal dimension and a change in the coordination number leading to stronger flocs.

  8. Algal biomass conversion to bioethanol - a step-by-step assessment.

    PubMed

    Harun, Razif; Yip, Jason W S; Thiruvenkadam, Selvakumar; Ghani, Wan A W A K; Cherrington, Tamara; Danquah, Michael K

    2014-01-01

    The continuous growth in global population and the ongoing development of countries such as China and India have contributed to a rapid increase in worldwide energy demand. Fossil fuels such as oil and gas are finite resources, and their current rate of consumption cannot be sustained. This, coupled with fossil fuels' role as pollutants and their contribution to global warming, has led to increased interest in alternative sources of energy production. Bioethanol, presently produced from energy crops, is one such promising alternative future energy source and much research is underway in optimizing its production. The economic and temporal constraints that crop feedstocks pose are the main downfalls in terms of the commercial viability of bioethanol production. As an alternative to crop feedstocks, significant research efforts have been put into utilizing algal biomass as a feedstock for bioethanol production. Whilst the overall process can vary, the conversion of biomass to bioethanol usually contains the following steps: (i) pretreatment of feedstock; (ii) hydrolysis; and (iii) fermentation of bioethanol. This paper reviews different technologies utilized in the pretreatment and fermentation steps, and critically assesses their applicability to bioethanol production from algal biomass. Two different established fermentation routes, single-stage fermentation and two-stage gasification/fermentation processes, are discussed. The viability of algal biomass as an alternative feedstock has been assessed adequately, and further research optimisation must be guided toward the development of cost-effective scalable methods to produce high bioethanol yield under optimum economy. PMID:24227697

  9. Evaluation of performance of full-scale duckweed and algal ponds receiving septage.

    PubMed

    Papadopoulos, Frantzis H; Metaxa, Eirini G; Iatrou, Miltos N; Papadopoulos, Aristotelis H

    2014-12-01

    The performance of duckweed and algal systems in removing fecal bacteria, organic matter, and nutrients was evaluated in three full-scale ponds operating in series. Trucks collected septage from holding tanks and discharged it into the system, daily. The inflow rates varied between the warm and the cold season. Duckweed and algae naturally colonized the ponds in two successive periods of 10 and 13 months, respectively. Environmental conditions were determined at various pond depths. Without harvesting, the duckweed system was neutral and anoxic. Alkaline and oversaturation conditions were observed in the algal system. The overall removals of 5-day biochemical oxygen demand, total suspended solids, total nitrogen removal, and orthophosphate (ortho-PO4(3-)) ranged from 94 to 97, 62 to 84, 68 to 74, and 0 to 26%, respectively. The E. coli and enterococci reductions varied between 2.2 to 3.0 and 1.1 to 1.4 log units, respectively. The upper values were always associated with the algal system. PMID:25654933

  10. Monitoring Algal Blooms in a Southwestern U.S. Reservoir System

    NASA Astrophysics Data System (ADS)

    Tarrant, Philip; Neuer, Susanne

    2009-02-01

    In recent years, several studies have explored the potential of higher-resolution sensor data for monitoring phytoplankton primary production in coastal areas and lakes. Landsat data have been used to monitor algal blooms [Chang et al., 2004; Vincent et al., 2004], and Moderate Resolution Imaging Spectroradiometer (MODIS) 250-meter and Medium Resolution Imaging Spectrometer (MERIS) full-resolution (300-meter) bands have been utilized to detect cyanobacterial blooms [Reinart and Kutser, 2006] as well as to monitor water quality [Koponen et al., 2004]. Field sampling efforts and MODIS 250-meter data are now being combined to develop a cost-effective method for monitoring water quality in a southwestern U.S. reservoir system. In the Phoenix, Ariz., metropolitan area, the Salt River reservoirs supply more than 3.5 million people, a population expected to rise to more than 6 million by 2030. Given that reservoir capacities have physical limitations, maintaining water quality will become critical as the population expands. Potentially noxious algal blooms that can release toxins and may affect water quality by modifying taste and odor have become a major concern in recent years. While frequent field sampling regimes are expensive, satellite imagery can be applied cost-effectively to monitor algal biomass trends remotely, and this information could provide early warning of blooms in these reservoirs.

  11. Variation of algal viability during electrochemical disinfection using Ti/RuO2 electrodes.

    PubMed

    Liang, Wenyan; Wang, Ke; Chen, Li; Ruan, Lingling; Sui, Lili

    2011-01-01

    This paper studied the influence of the operating conditions, e.g., current density, electrolyte and exposure time, on the variation of the algal viability during electrochemical disinfection processes. An electrochemical tube employing Ti/RuO2 as anodes was constructed for inactivation of cyanobacteria (often called blue-green algae) Microcystis aeruginosa. Viability of algal cells was determined by 2,3,5-triphenyl-tetrazoliumchloride (TTC) dehydrogenase activity assay and neutral red (NR) staining assay. Algal suspensions with cell density of 5-7 x 10(9) L(-1) were exposed to current densities from 1 to 8 mA cm(-2) at room temperature (25-30 degrees C) for 30 min. The results showed that the cell viability decreased obviously with the increase of current density. After exposure to 4 mA cm(-2) for more than 7 min, Microcystis aeruginosa didn't have the ability to resume growth. Comparative disinfection tests with different electrolytes were conducted, including chlorides, sulfates, nitrates and phosphates. Microcystis aeruginosa appeared to be sensitive to electro-generated chlorine oxidants. The inactivation effect was also demonstrated to occur in chlorine-free electrolytes. However, decrease of the inactivation effect by adding ascorbic acid as an oxidant scavenger indicated that the reactive oxygen species, especially *OH radicals, played an important role for chlorine-free electrolytes. PMID:22053471

  12. Acid-Catalyzed Algal Biomass Pretreatment for Integrated Lipid and Carbohydrate-Based Biofuels Production

    SciTech Connect

    Laurens, L. M. L.; Nagle, N.; Davis, R.; Sweeney, N.; Van Wychen, S.; Lowell, A.; Pienkos, P. T.

    2014-11-12

    One of the major challenges associated with algal biofuels production in a biorefinery-type setting is improving biomass utilization in its entirety, increasing the process energetic yields and providing economically viable and scalable co-product concepts. We demonstrate the effectiveness of a novel, integrated technology based on moderate temperatures and low pH to convert the carbohydrates in wet algal biomass to soluble sugars for fermentation, while making lipids more accessible for downstream extraction and leaving a protein-enriched fraction behind. We studied the effect of harvest timing on the conversion yields, using two algal strains; Chlorella and Scenedesmus, generating biomass with distinctive compositional ratios of protein, carbohydrate, and lipids. We found that the late harvest Scenedesmus biomass had the maximum theoretical biofuel potential at 143 gasoline gallon equivalent (GGE) combined fuel yield per dry ton biomass, followed by late harvest Chlorella at 128 GGE per ton. Our experimental data show a clear difference between the two strains, as Scenedesmus was more successfully converted in this process with a demonstrated 97 GGE per ton. Our measurements indicated a release of >90% of the available glucose in the hydrolysate liquors and an extraction and recovery of up to 97% of the fatty acids from wet biomass. Techno-economic analysis for the combined product yields indicates that this process exhibits the potential to improve per-gallon fuel costs by up to 33% compared to a lipids-only process for one strain, Scenedesmus, grown to the mid-point harvest condition.

  13. Landsat TM image feature extraction and analysis of algal bloom in Taihu Lake

    NASA Astrophysics Data System (ADS)

    Wei, Yuchun; Chen, Wei

    2008-04-01

    This study developed an approach to the extraction and characterization of blue-green algal blooms of the study area Taihu Lake of China with the Landsat 5 TM imagery. Spectral feature of typical material within Taihu Lake were first compared, and the most sensitive spectral bands to blue-green algal blooms determined. Eight spectral indices were then designed using multiple TM spectral bands in order to maximize spectral contrast of different materials. The spectral curves describing the variation of reflectance at individual bands with the spectral indices were plotted, and the TM imagery was segmented using as thresholds the step-jumping points of the reflectance curves. The results indicate that the proposed multiple band-based spectral index NDAI2 (NDAI2 = (B4-B1)*(B5-B3)/(B4+B5+B1+B3) performed better than traditional vegetation indices NDVI and RVI in the extraction of blue-green algal information. In addition, this study indicates that the image segmentation using the points where reflectance has a sudden change resulted in a robust result, as well as a good applicability.

  14. Algal bloom sedimentation induces variable control of lake eutrophication by phosphorus inactivating agents.

    PubMed

    Wang, Changhui; Bai, Leilei; Jiang, He-Long; Xu, Huacheng

    2016-07-01

    Lake eutrophication typically occurs with a syndrome of algae breeding and biomass accumulation (e.g., algal blooms). Therefore, the effect of algal bloom sedimentation on eutrophication control by phosphorus (P) inactivating agents was assessed herein. Three commercial products, including aluminum (Al) sulfate, iron (Fe) sulfate, and a lanthanum-modified clay (Phoslock®), as well as one easily available by-product, drinking water treatment residue (DWTR), were selected. The most important finding was that during algae sedimentation, P immobilization from the overlying water by Al, Phoslock®, and DWTR was dominated by a long-term slow phase (>150d), while Fe has limited effectiveness on the immobilization. Further analysis indicated that the algae sedimentation effect was mainly due to the slow release of P from algae, leading to relatively limited P available for the inactivating agents. Then, a more unfavorable effect on the P immobilization capability of inactivating agents was caused by the induced anaerobic conditions, the released organic matter from algae, and the increased sulfide in the overlying water and sediments during sedimentation. Overall, algae sedimentation induced variable control of eutrophication by P inactivating agents. Accordingly, recommendations for future works about algal lake restoration were also proposed. PMID:27017078

  15. In-depth characterization of wastewater bacterial community in response to algal growth using pyrosequencing.

    PubMed

    Lee, Jangho; Lee, Juyoun; Lee, Tae Kwon; Woo, Sung-Geun; Baek, Gyu Seok; Park, Joonhong

    2013-10-28

    Microalgae have been regarded as a natural resource for sustainable materials and fuels, as well as for removal of nutrients and micropollutants from wastewater, and their interaction with bacteria in wastewater is a critical factor to consider because of the microbial diversity and complexity in a variety of wastewater conditions. Despite their importance, very little is known about the ecological interactions between algae and bacteria in a wastewater environment. In this study, we characterized the wastewater bacterial community in response to the growth of a Selenastrum gracile UTEX 325 population in a real municipal wastewater environment. The Roche 454 GS-FLX Titanium pyrosequencing technique was used for indepth analysis of amplicons of 16S rRNA genes from different conditions in each reactor, with and without the algal population. The algal growth reduced the bacterial diversity and affected the bacterial community structure in the wastewater. The following in-depth analysis of the deep-sequenced amplicons showed that the algal growth selectively stimulated Sphingobacteria class members, especially the Sediminibacterium genus population, in the municipal wastewater environment. PMID:23867704

  16. Coralline algal physiology is more adversely affected by elevated temperature than reduced pH.

    PubMed

    Vásquez-Elizondo, Román Manuel; Enríquez, Susana

    2016-01-01

    In this study we analyzed the physiological responses of coralline algae to ocean acidification (OA) and global warming, by exposing algal thalli of three species with contrasting photobiology and growth-form to reduced pH and elevated temperature. The analysis aimed to discern between direct and combined effects, while elucidating the role of light and photosynthesis inhibition in this response. We demonstrate the high sensitivity of coralline algae to photodamage under elevated temperature and its severe consequences on thallus photosynthesis and calcification rates. Moderate levels of light-stress, however, were maintained under reduced pH, resulting in no impact on algal photosynthesis, although moderate adverse effects on calcification rates were still observed. Accordingly, our results support the conclusion that global warming is a stronger threat to algal performance than OA, in particular in highly illuminated habitats such as coral reefs. We provide in this study a quantitative physiological model for the estimation of the impact of thermal-stress on coralline carbonate production, useful to foresee the impact of global warming on coralline contribution to reef carbon budgets, reef cementation, coral recruitment and the maintenance of reef biodiversity. This model, however, cannot yet account for the moderate physiological impact of low pH on coralline calcification. PMID:26740396

  17. Synergistic effects of algal overgrowth and corallivory on Caribbean reef-building corals.

    PubMed

    Wolf, Alexander T; Nugues, Maggy M

    2013-08-01

    Indirect biotic interactions play a crucial role in structuring ecological communities, but many of these interactions have not been explored. Algal competition and corallivory are two major stressors contributing to the decline of coral reefs. Here, we provide the first evidence of algal-induced corallivory and synergistic effects between the two stressors on corals. When corals (Montastraeafaveolata) were placed in contact with algae (Halimeda opuntia) together with corallivorous fireworms (Hermodice carunculata) in aquaria, corals suffered high tissue mortality. This mortality was reduced in the presence of algae only, and no mortality occurred in the presence of fireworms only or when excluding both algae and fireworms. These findings were supported by field observations showing a predominance of fireworms inside algae contacting live corals, and by an in situ experiment demonstrating higher coral mortality in contact with algae left undisturbed than with algae from which all mobile epifauna were periodically removed. Among the main contributing mechanisms, we suggest that algal contact produces decaying coral tissue that attracts the corallivore and enhances its aggregation behavior. Our study demonstrates an indirect effect pathway by which algae can impact corals, which shares similarities with the classic models of apparent competition and habitat facilitation. PMID:24015510

  18. Coralline algal physiology is more adversely affected by elevated temperature than reduced pH

    PubMed Central

    Vásquez-Elizondo, Román Manuel; Enríquez, Susana

    2016-01-01

    In this study we analyzed the physiological responses of coralline algae to ocean acidification (OA) and global warming, by exposing algal thalli of three species with contrasting photobiology and growth-form to reduced pH and elevated temperature. The analysis aimed to discern between direct and combined effects, while elucidating the role of light and photosynthesis inhibition in this response. We demonstrate the high sensitivity of coralline algae to photodamage under elevated temperature and its severe consequences on thallus photosynthesis and calcification rates. Moderate levels of light-stress, however, were maintained under reduced pH, resulting in no impact on algal photosynthesis, although moderate adverse effects on calcification rates were still observed. Accordingly, our results support the conclusion that global warming is a stronger threat to algal performance than OA, in particular in highly illuminated habitats such as coral reefs. We provide in this study a quantitative physiological model for the estimation of the impact of thermal-stress on coralline carbonate production, useful to foresee the impact of global warming on coralline contribution to reef carbon budgets, reef cementation, coral recruitment and the maintenance of reef biodiversity. This model, however, cannot yet account for the moderate physiological impact of low pH on coralline calcification. PMID:26740396

  19. Role of initial cell density of algal bioassay of toxic chemicals.

    PubMed

    Singh, Prashant Kumar; Shrivastava, Alok Kumar

    2016-07-01

    A variety of toxicants such as, metal ions, pesticides, dyes, etc. are continuously being introduced anthropogenically in the environment and adversely affect to the biotic component of the ecosystem. Therefore, the assessment of negative effects of these toxicants is required. However, toxicity assessment anticipated by chemical analysis are extremely poor, therefore the application of the living systems for the same is an excellent approach. Concentration of toxicant as well as cell density both influenced the result of the algal toxicity assay. Here, Scenedesmus sp, a very fast growing green microalgae was selected for study the effects of initial cell densities on the toxicity of Cu(II), Cd(II), Zn(II), paraquat and 2,4-D. Results demonstrated concentration dependent decrease in biomass and specific growth rate of Scenedesmus sp. on exposure of abovesaid toxicants. Paraquat and 2,4-D emerged as extremely toxic to the test alga which reflected from the lowest EC value and very steep decline in biomass was evident with increasing concentration of paraquat and 2,4-D in the medium. Result also demonstrated that initial cell density is a very important parameter than specific growth rate for algal bioassay of various toxicants. Present study clearly illustrated that the use of smaller cell density is always recommended for assaying toxicity of chemicals in algal assays. PMID:26593761

  20. Formation of harmful algal blooms cannot be explained by allelopathic interactions

    PubMed Central

    Jonsson, Per R.; Pavia, Henrik; Toth, Gunilla

    2009-01-01

    Many planktonic microalgae produce a range of toxins and may form harmful algal blooms. One hypothesis is that some toxins are allelopathic, suppressing the growth of competitors, and it has been suggested that allelopathy may be one important mechanism causing algal blooms. In a metaanalysis of recent experimental work, we looked for evidence that allelopathy may explain the initiation of algal blooms. With few exceptions, allelopathic effects were only significant at very high cell densities typical of blooms. We conclude that there is no experimental support for allelopathy at prebloom densities, throwing doubts on allelopathy as a mechanism in bloom formation. Most studies tested allelopathy using cell-free manipulations. With simple models we show that cell-free manipulations may underestimate allelopathy at low cell densities if effects are transmitted during cell–cell interactions. However, we suggest that the evolution of allelopathy under field conditions may be unlikely even if based on cell–cell interactions. The spatial dispersion of cells in turbulent flow will make it difficult for an allelopathic cell to receive an exclusive benefit, and a dispersion model shows that dividing cells are rapidly separated constraining clone selection. Instead, we propose that reported allelopathic effects may be nonadaptive side effects of predator–prey or casual parasitic cell–cell interactions. PMID:19549831

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

    PubMed

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

    2016-04-15

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

  2. High-Throughput Biosensor Discriminates Between Different Algal H2-Photoproducing Strains

    SciTech Connect

    Wecker, Matt S. A.; Maria L. Ghirardi

    2014-02-27

    A number of species of microalgae and cyanobacteria photosynthetically produce H2 gas by coupling water oxidation with the reduction of protons to molecular hydrogen, generating renewable energy from sunlight and water. Photosynthetic H2 production, however, is transitory, and there is considerable interest in increasing and extending it for commercial applications. Here we report a Petri-plate version of our previous, microplate-based assay that detects photosynthetic H2 production by algae. The assay consists of an agar overlay of H2-sensing Rhodobacter capsulatus bacteria carrying a green fluorescent protein that responds to H2 produced by single algal colonies in the bottom agar layer. The assay distinguishes between algal strains that photoproduce H2 at different levels under high light intensities, and it does so in a simple, inexpensive, and high-throughput manner. The assay will be useful for screening both natural populations and mutant libraries for strains having increased H2 production, and useful for identifying various genetic factors that physiologically or genetically alter algal hydrogen production.

  3. Algal endosymbionts in European Hydra strains reflect multiple origins of the zoochlorella symbiosis.

    PubMed

    Rajević, Nives; Kovačević, Goran; Kalafatić, Mirjana; Gould, Sven B; Martin, William F; Franjević, Damjan

    2015-12-01

    Symbiotic associations are of broad significance in evolution and biodiversity. Green Hydra is a classic example of endosymbiosis. In its gastrodermal myoepithelial cells it harbors endosymbiotic unicellular green algae, most commonly from the genus Chlorella. We reconstructed the phylogeny of cultured algal endosymbionts isolated and maintained in laboratory conditions for years from green Hydra strains collected from four different geographical sites within Croatia, one from Germany and one from Israel. Nuclear (18S rDNA, ITS region) and chloroplast markers (16S, rbcL) for maximum likelihood phylogenetic analyses were used. We focused on investigating the positions of these algal endosymbiotic strains within the chlorophyte lineage. Molecular analyses established that different genera and species of unicellular green algae are present as endosymbionts in green Hydra, showing that endosymbiotic algae growing within green Hydra sampled from four Croatian localities are not monophyletic. Our results indicate that the intracellular algal endosymbionts of green Hydra have become established several times independently in evolution. PMID:26220839

  4. Relationships between primary production and irradiance in coral reef algal communities

    SciTech Connect

    Not Available

    1985-07-01

    Shallow water algal turf communities are the major primary producers on coral reefs. High rates of primary production are maintained despite extremely high light intensities and exposure to ultraviolet wavelengths. The relationships between the light intensity and primary production in these assemblages are typical of algae adapted to a high light environment (low ..cap alpha.. (initial slope), high I/sub k/ (saturating light intensity), and high I/sub c/ (compensation point light intensity)). Seasonal variations in algal standing crop due to herbivory and daylength result in some characteristic photoadaptive changes in ..cap alpha.. I/sub k/, and I/sub c/ and changes in Pnet/sub max/ rates (maximum net photosynthetic rate achieved at light saturation) on both a chlorophyll ..cap alpha.. and an areal basis. Exposure to UV wavelength results in significantly higher respiration rates but no changes in ..cap alpha.., Pnet/sub max/, or I/sub k/, when compared with these parameters for the same algal communities incubated at the same light intensities without UV wavelengths. The apparent lack of photoinhibition in these algae allows calculation of the daily integrated production from the P vs. I parameters. This integrated production is highest in July (3.1 +/- 0.2 g C m/sup -2/d/sup -1/) and is reduced by 30% from this maximum in December (2.1 +/- 0.1 g C m/sup -2/d/sup -1/).

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  6. Seasonal determinations of algal virus decay rates reveal overwintering in a temperate freshwater pond.

    PubMed

    Long, Andrew M; Short, Steven M

    2016-07-01

    To address questions about algal virus persistence (i.e., continued existence) in the environment, rates of decay of infectivity for two viruses that infect Chlorella-like algae, ATCV-1 and CVM-1, and a virus that infects the prymnesiophyte Chrysochromulina parva, CpV-BQ1, were estimated from in situ incubations in a temperate, seasonally frozen pond. A series of experiments were conducted to estimate rates of decay of infectivity in all four seasons with incubations lasting 21 days in spring, summer and autumn, and 126 days in winter. Decay rates observed across this study were relatively low compared with previous estimates obtained for other algal viruses, and ranged from 0.012 to 11% h(-1). Overall, the virus CpV-BQ1 decayed most rapidly whereas ATCV-1 decayed most slowly, but for all viruses the highest decay rates were observed during the summer and the lowest were observed during the winter. Furthermore, the winter incubations revealed the ability of each virus to overwinter under ice as ATCV-1, CVM-1 and CpV-BQ1 retained up to 48%, 19% and 9% of their infectivity after 126 days, respectively. The observed resilience of algal viruses in a seasonally frozen freshwater pond provides a mechanism that can support the maintenance of viral seed banks in nature. However, the high rates of decay observed in the summer demonstrate that virus survival and therefore environmental persistence can be subject to seasonal bottlenecks. PMID:26943625

  7. An analysis of the productivity of a CELSS continuous algal culture system

    NASA Technical Reports Server (NTRS)

    Radmer, R.; Behrens, P.; Fernandez, E.; Arnett, K.

    1986-01-01

    One of the most attractive aspects of using algal cultures as plant components for a Closed Ecological Life Support Systems (CELSS) is the efficiency with which they can be grown. Although algae are not necessarily intrinsically more efficient than higher plants, the ease which they can be handled and manipulated (more like chemical reagents than plants), and the culturing techniques available, result in much higher growth rates than are usually attainable with higher plants. Furthermore, preliminary experiments have demonstrated that algal growth and physiology is not detectable altered in a microgravity environment, (1) whereas the response of higher plants to zero gravity is unknown. In order to rationally design and operate culture systems, it is necessary to understand how the macroparameters of a culture system, e.g., productivity, are related to the physiological aspects of the algal culture. A first principles analysis of culture system is discussed, and a mathematical model that describes the relationship of culture productivity to the cell concentration of light-limited culture is derived. The predicted productivity vs cell concentration curve agrees well with the experimental data obtained to test this model, indicating that this model permits an accurate prediction of culture productivity given the growth parameters of the system.

  8. High-throughput biosensor discriminates between different algal H2 -photoproducing strains.

    PubMed

    Wecker, Matt S A; Ghirardi, Maria L

    2014-07-01

    A number of species of microalgae and cyanobacteria photosynthetically produce H2 gas by coupling water oxidation with the reduction of protons to molecular hydrogen, generating renewable energy from sunlight and water. Photosynthetic H2 production, however, is transitory, and there is considerable interest in increasing and extending it for commercial applications. Here we report a Petri-plate version of our previous, microplate-based assay that detects photosynthetic H2 production by algae. The assay consists of an agar overlay of H2 -sensing Rhodobacter capsulatus bacteria carrying a green fluorescent protein that responds to H2 produced by single algal colonies in the bottom agar layer. The assay distinguishes between algal strains that photoproduce H2 at different levels under high light intensities, and it does so in a simple, inexpensive, and high-throughput manner. The assay will be useful for screening both natural populations and mutant libraries for strains having increased H2 production, and useful for identifying various genetic factors that physiologically or genetically alter algal hydrogen production. PMID:24578287

  9. Why It Is Time to Look Beyond Algal Genes in Photosynthetic Slugs

    PubMed Central

    Rauch, Cessa; de Vries, Jan; Rommel, Sophie; Rose, Laura E.; Woehle, Christian; Christa, Gregor; Laetz, Elise M.; Wägele, Heike; Tielens, Aloysius G.M.; Nickelsen, Jörg; Schumann, Tobias; Jahns, Peter; Gould, Sven B.

    2015-01-01

    Eukaryotic organelles depend on nuclear genes to perpetuate their biochemical integrity. This is true for mitochondria in all eukaryotes and plastids in plants and algae. Then how do kleptoplasts, plastids that are sequestered by some sacoglossan sea slugs, survive in the animals’ digestive gland cells in the absence of the algal nucleus encoding the vast majority of organellar proteins? For almost two decades, lateral gene transfer (LGT) from algae to slugs appeared to offer a solution, but RNA-seq analysis, later supported by genome sequencing of slug DNA, failed to find any evidence for such LGT events. Yet, isolated reports continue to be published and are readily discussed by the popular press and social media, making the data on LGT and its support for kleptoplast longevity appear controversial. However, when we take a sober look at the methods used, we realize that caution is warranted in how the results are interpreted. There is no evidence that the evolution of kleptoplasty in sea slugs involves LGT events. Based on what we know about photosystem maintenance in embryophyte plastids, we assume kleptoplasts depend on nuclear genes. However, studies have shown that some isolated algal plastids are, by nature, more robust than those of land plants. The evolution of kleptoplasty in green sea slugs involves many promising and unexplored phenomena, but there is no evidence that any of these require the expression of slug genes of algal origin. PMID:26319575

  10. Tracking the Effect of Algal Mats on Coral Bleaching Using Remote Sensing

    NASA Astrophysics Data System (ADS)

    El-Askary, H. M.; Johnson, S. H.; Idris, N.; Qurban, M. A. B.

    2014-12-01

    Benthic habitats rely on relatively stable environmental conditions for survival. The introduction of algal mats into an ecosystem can have a notable effect on the livelihood of organisms such as coral reefs by causing changes in the biogeochemistry of the surrounding water. Increasing levels of acidity and new competition for sunlight caused by congregations of cyanobacteria essentially starve coral reefs of natural resources. These changes are particularly prevalent in waters near quickly developing population centers, such as the ecologically diverse Arabian Gulf. While ground-truthing studies to determine the extensiveness of coral death proves useful on a microcosmic level, new ventures in remote sensing research allow scientists to utilize satellite data to track these changes on a broader scale. Satellite images acquired from Landsat 5, 1987, Landsat 7, 2000, and Landsat 8, 2013 along with higher resolution IKONOS data are digitally analyzed in order to create spectral libraries for relevant benthic types, which in turn can be used to perform supervised classifications and change detection analyses over a larger area. The supervised classifications performed over the three scenes show five significant marine-related classes, namely coral, mangroves, macro-algae, and seagrass, in different degrees of abundance, yet here we focus only on the algal mats impact on corals bleaching. The change detection analysis is introduced to study see the degree of algal mats impact on coral bleaching over the course of time with possible connection to the local meteorology and current climate scenarios.

  11. Biodiesel from wastewater: lipid production in high rate algal pond receiving disinfected effluent.

    PubMed

    Assemany, Paula Peixoto; Calijuri, Maria Lucia; do Couto, Eduardo de Aguiar; Santiago, Aníbal Fonseca; Dos Reis, Alberto José Delgado

    2015-01-01

    The production of different species of microalgae in consortium with other micro-organisms from wastewaters may represent an alternative process, to reduce the costs, for obtaining biofuels. The aim of this study was to evaluate the influence of pre-ultraviolet disinfection (UV) in the production of lipids from biomass produced in high rate ponds. Two high rate algal ponds were evaluated: a pond that received domestic sewage without disinfection and the other receiving domestic sewage previously disinfected by UV radiation (uvHRAP). The UV disinfection did not lead to significant differences in fatty acid profile and total lipid productivities, although it increased algal biomass concentration and productivity as well as lipid content. Moreover, the overall biomass concentrations and productivities decreased with the UV disinfection, mostly as a consequence of a loss in bacterial load. We thus conclude that uvHRAP disinfection may represent a potential strategy to promote the cleaner and safer growth of algal biomass when cultivated in consortium with other micro-organisms. Mainly regarding the use of wastewater as culture medium, together with a cheaper production of lipids for biodiesel, pre-disinfection may represent an advance since extraction costs could be significantly trimmed due to the increase in lipid content. PMID:25909734

  12. Determination of the algal growth-limiting nutrients in strip mine ponds

    SciTech Connect

    Bucknavage, M.J.; Aharrah, E.C.

    1984-12-01

    Using both a test organism, Ankistrodesmus falcatus, and natural phytoplankton, the Printz Algal Assay Bottle Test was used to determine the algal growth limiting nutrients in two strip mine ponds. Nitrogen, phosphorus, and iron were investigated, singly and in combination, as possible limiting nutrients. A synthetic chelator, Na/sub 2/EDTA, was also used in the assay to test for the presence of metal toxicants and/or trace metal limitation. Because bacteria have a major influence on water chemistry, a separate assay incorporating the natural bacteria population was performed. In both ponds, assay results using test alga indicate phosphorus to be the primary limiting nutrient and nitrogen as a secondary factor. The presence of EDTA in combination with phosphate containing treatment promoted a higher algal concentration in both ponds. Iron was determined to be a secondary limiting nutrient in only one of the ponds. Natural phytoplankton of the two ponds responded in a similar manner to nutrient increases. Only one pond had the same results produced by both assays. Nutrient availability was influenced by the presence of bacteria in one pond but not in the other.

  13. No-observed-effect concentrations in batch and continuous algal toxicity tests

    SciTech Connect

    Chao, M.R.; Chen, C.Y.

    2000-06-01

    In this study, the authors compare the no-observed-effect concentrations (NOECs) of Cd, Ni, Zn, Cu, and Pb based on different response parameters, using batch and continuous algal toxicity tests. For both batch and continuous tests, parameters based on total cell volume (TCV) were found to be less sensitive than those related to cell densities. The above observation mainly occurred because, under the stresses from metal toxicants evaluated in this and a previous study, the mean cell volume (MCV) of algae increased considerably. The increase of MCV compensates for the effects brought about by the reduction in cell density and eventually results in less variation in TCVs. This study shows that parameters based on cell density are quite sensitive and ideal for the estimation of NOECs. In addition, comparison of the NOEC values derived from different culture techniques shows that the continuous methods generally yields lower NOEC values than that obtained by the batch tests. The results of this study also indicate that the NOEC provides more protection to the test organism than the effective concentration at 10% growth reduction (EC10). For toxicity test methods that produce small variations among replicates, the NOEC is still a good indicator of low toxic effect. Furthermore, for the continuous algal toxicity test, a relatively simple approach is proposed to determine the NOEC values based on the algal culture's control charts. The proposed method produced identical results as those based on conventional hypothesis-testing methods.

  14. Selective recovery of gold and other metal ions from an algal biomass

    SciTech Connect

    Darnall, D.W.; Greene, B.; Henzl, M.T.; Hosea, J.M.; McPherson, R.A.; Sneddon, J.; Alexander, M.D.

    1986-02-01

    The authors observed that the pH dependence of the binding of Au/sup 3 +/, Ag/sup +/, and Hg/sup 2 +/ to the algae Chlorella vulgaris is different than the binding of other metal ions. Between pH 5 and 7, a variety of metal ions bind strongly to the cell surface. Most of these algal-bound metal ions can be selectively desorbed by lowering the pH to 2; however, Au/sup 3 +/, Hg/sup 2 +/, and Ag/sup +/ are all bound strongly at pH 2. Addition of a strong ligand at different pHs is required to elute these ions from the algal surface. Algal-bound gold and mercury can be selectively eluted by using mercaptoethanol. An elution scheme is demonstrated for the binding and selective recovery of Cu/sup 2 +/, Zn/sup 2 +/, Au/sup 3 +/, and Hg/sup 2 +/ from an equimolar mixture. 20 references, 2 figures.

  15. Sludge-grown algae for culturing aquatic organisms: Part I. Algal growth in sludge extracts

    NASA Astrophysics Data System (ADS)

    Hung, K. M.; Chiu, S. T.; Wong, M. H.

    1996-05-01

    This project is aimed at studying the feasibility of using sewage sludge to prepare culture media for microalgae ( Chlorella-HKBU) and the use of the sludge-grown algae as a feed for some aquatic organisms. Part I of the project included results on preparing sludge extracts and their use on algal culture. By comparing two culturing techniques, “aeration” and “shaking,” it was noted that both lag and log phases were shortened in the aeration system. A subsequent experiment noted that algal growth subject to aeration rates of 1.0 and 1.5 liters/min had similar lag and log phases. In addition, both aeration rates had a significantly higher ( P < 0.05) final cell density than that of 0.5 liters/min. A detailed study on the variation of growth conditions on the algal growth was done. The results indicated that pH values of all the cultures declined below 5 at day 12. The removal rates of ammonia N ranged from 62% to 70%. The sludge-grown algae contained a rather substantial amount of heavy metals (µg/g): Zn 289 581, Cu 443 682, Ni 310 963, Mn 96 126, Cr 25 118, and Fe 438 653. This implied that the rather high levels of heavy metals may impose adverse effects on higher trophic organisms.

  16. Algal Biomass Constituent Analysis: Method Uncertainties and Investigation of the Underlying Measuring Chemistries

    SciTech Connect

    Laurens, L. M. L.; Dempster, T. A.; Jones, H. D. T.; Wolfrum, E. J.; Van Wychen, S.; McAllister, J. S. P.; Rencenberger, M.; Parchert, K. J.; Gloe, L. M.

    2012-02-21

    Algal biomass compositional analysis data form the basis of a large number of techno-economic process analysis models that are used to investigate and compare different processes in algal biofuels production. However, the analytical methods used to generate these data are far from standardized. This work investigated the applicability of common methods for rapid chemical analysis of biomass samples with respect to accuracy and precision. This study measured lipids, protein, carbohydrates, ash, and moisture of a single algal biomass sample at 3 institutions by 8 independent researchers over 12 separate workdays. Results show statistically significant differences in the results from a given analytical method among laboratories but not between analysts at individual laboratories, suggesting consistent training is a critical issue for empirical analytical methods. Significantly different results from multiple lipid and protein measurements were found to be due to different measurement chemistries. We identified a set of compositional analysis procedures that are in best agreement with data obtained by more advanced analytical procedures. The methods described here and used for the round robin experiment do not require specialized instrumentation, and with detailed analytical documentation, the differences between laboratories can be markedly reduced.

  17. Effects of modified clay on cysts of Scrippsiella trochoidea for harmful algal bloom control

    NASA Astrophysics Data System (ADS)

    Wang, Zhifu; Yu, Zhiming; Song, Xiuxian; Cao, Xihua; Han, Xiaotian

    2014-11-01

    We present results on the effect of modified clay on cyst formation of Scrippsiella trochoidea in harmful algal bloom (HAB). Modified clay (in concentration of 0, 0.1, 0.5, and 1.0 g/L) were added to cultures, and observations were made on cysts of S. trochoidea under controlled laboratory conditions. Results indicate that the removal rate of algal cells reached 97.7% at the clay concentration of 1.0 g/L. The cyst formation rate increased from 4.6% to 24.6% when the concentration of clay was increased from 0 to 1.0 g/L. Two cyst metamorphs were observed: spinal calcareous cysts and smooth noncalcareous ones. The proportion of the spinal cysts decreased from 76.9% to 24.1% when clay concentration increased from 0 to 1.0 g/L. In addition, modified clay affected cyst germination. The germination rate decreased with the increases in the clay concentrations. Non-calcareous cysts had a lower germination rate with a longer germination time. We conclude that modified clay could depress algal cell multiplication and promote formation of temporal cysts of S. trochoidea, which may help in controlling HAB outbreaks.

  18. A catchment-scale palaeolimnological investigation into multiple forcings of algal community change

    NASA Astrophysics Data System (ADS)

    Moorhouse, H. L.; McGowan, S.; Jones, M.; Brayshaw, S.; Barker, P.; Leavitt, P.

    2013-12-01

    A catchment-scale palaeolimnological investigation of sedimentary algal pigments spanning the past ~200 years was undertaken on lakes which drain into Windermere, England's largest and longest lake. We aimed to determine the relative influence of past regional (climatic, atmospheric deposition) and local (land-use, hydrological modification, point-source pollution) drivers of algal community change by comparing three fertile lowland lakes (Blelham Tarn, Esthwaite Water and Rydal Water) and two upland tarns (Stickle and Easedale Tarns) to better inform a catchment-wide management strategy for Windermere. Drivers of change at the upland sites included atmospheric acid deposition, climatic change and structural modifications caused by dam installation, whereas the influence of agriculture and point-source pollution is greater in the lakes in the lowland parts of the catchment. As a result, contrasting algal responses were noted in the lakes. For example, the cyanobacterial pigment zeaxanthin and the cryptophte pigment alloxanthin increased at Stickle Tarn (359% and 321% respectively) corresponding with the establishment of a dam at the outflow of the tarn in 1838. However, post-1900's the concentration of these pigments declined both at Stickle and at Easedale Tarn coincident with increased storm events and in the later decades of the century (~1980s onwards) decreases in acid deposition. In the lowland sites the cyanobacterial pigment aphanizophyll increased by 400-7000% and the indicator of total algal production β-carotene increased as much as six-fold indicating a substantial degradation in water quality and the onset of cyanobacterial blooms since the 1950's. In the lowland sites, degradation of water quality was closely linked to sewage installations and treatment work upgrades during the 1950's-70's and intensification of agricultural practices most notably increases in sheep stocking densities, which expanded in the 1950's. In lowland lakes with a higher

  19. Stimulation of delta-Aminolevulinic Acid Formation in Algal Extracts by Heterologous RNA.

    PubMed

    Weinstein, J D; Mayer, S M; Beale, S I

    1986-12-01

    Formation of the chlorophyll and heme precursor delta-aminolevulinic acid (ALA) from glutamate in soluble extracts of Chlorella vulgaris, Euglena gracilis, and Cyanidium caldarium was stimulated by addition of low molecular weight RNA derived from greening algae or plant tissue. Enzyme extracts were prepared for the ALA formation assay by high-speed centrifugation, partial RNA depletion, and gel filtration through Sephadex G-25. RNA was extracted from greening barley epicotyls, greening cucumber cotyledon chloroplasts, and growing cells of Chlorella, Euglena, Chlamydomonas reinhardtii, and Anacystis nidulans, freed of protein, and fractionated on DEAE-cellulose to yield an active component corresponding to the tRNA-containing fraction. RNA from homologous and heterologous species stimulated ALA formation when added to enzyme extracts, and the degree of stimulation was proportional to the amount of RNA added. Algal enzyme extracts were stimulated by algal RNAs interchangeably, with the exception of RNA prepared from aplastidic Euglena, which did not stimulate ALA production. RNA from greening cucumber cotyledon chloroplasts and greening barley epicotyls stimulated ALA formation in algal enzyme incubations. In contrast, tRNA from Escherichia coli, both nonspecific and glutamate-specific, as well as wheat germ, bovine liver, and yeast tRNA, failed to reconstitute ALA formation. Moreover, E. coli tRNA inhibited ALA formation by algal extracts, both in the presence and absence of added algal RNA. Chlorella extracts were capable of catalyzing aminoacyl bond formation between glutamate and both the activity reconstituting and nonreconstituting RNAs, indicating that the inability of some RNAs to stimulate ALA formation was not due to their inability to serve as glutamyl acceptors. The first step in the ALA-forming reaction sequence has been proposed to be activation of glutamate via aminoacyl bond formation with a specific tRNA, analogous to the first step in peptide bond

  20. Comparative performance studies of water lettuce, duckweed, and algal-based stabilization ponds using low-strength sewage.

    PubMed

    Awuah, Esi; Oppong-Peprah, M; Lubberding, H J; Gijzen, H J

    A bench-scale continuous-flow wastewater treatment system comprising three parallel lines using duckweed (Spirodela polyrhiza), water lettuce (Pistia stratiotes), and algae (natural colonization) as treatment agents was set up to determine environmental conditions, fecal coliform profiles and general treatment performance. Each line consisted of four ponds connected in series fed by diluted sewage. Influent and effluent parameters measured included environmental conditions, turbidity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), nitrate, nitrite, ammonia, total phosphorus, fecal coliforms, mosquito larvae, and sludge accumulations. Environmental conditions and fecal coliforms profiles were determined in the sediments (0.63 m), suspensions (0.35 m), and surfaces (0.1 m) of each pond. Acidic conditions were observed in the pistia ponds, neutral conditions in duckweed ponds, and alkaline conditions in algal ponds. Fecal coliforms log removals of 6, 4, and 3 were observed in algal, duckweed, and pistia ponds, respectively, in the final effluents, with die-off rates per pond of 2.7, 2.0, and 1.6. Sedimentation accounted for over 99% fecal coliform removal in most of the algal and pistia ponds. BOD removal was highest in the duckweed system, followed by pistia and algae at 95%, 93%, and 25%, respectively. COD removals were 65% and 59%, respectively, for duckweed and pistia, while COD increased in algal ponds by 56%. Nitrate removals were 72%, 70%, and 36%, respectively for duckweed, pistia, and algal ponds. Total phosphorus removals were 33% and 9% for pistia and duckweed systems, while an increase of 19% was observed in the algal treatment system. Ammonia removals were 95% in both pistia and duckweed and 93% in algal systems. Removals of total dissolved solids (TDS) were 70% for pistia, 15% for duckweed, and 9% for algae. Mosquito populations of 11,175/m(2), 3516/m(2), and 96/m(2) were counted in pistia, algal, and duckweed ponds, respectively. Low

  1. Cost structures and life cycle impacts of algal biomass and biofuel production

    NASA Astrophysics Data System (ADS)

    Christiansen, Katrina Lea

    2011-12-01

    Development and extraction of energy sources, energy production and energy use have huge economic, environmental and geopolitical impacts. Increasing energy demands in tandem with reductions in fossil fuel production has led to significant investments in research into alternative forms of energy. One that is promising but yet not commercially established is the production of biofuel from algae. This research quantitatively assessed the potential of algae biofuel production by examining its cost and environmental impacts. First, two models developed by the RAND corporation were employed to assess Cost Growth defined as the ratio of actual costs to estimated costs, and Plant Performance defined as the ratio of actual production levels to design performance, of three algal biofuel production technologies. The three algal biofuel production technologies examined to open raceway ponds (ORPs), photobioreactors (PBRs), and a system that couples PBRs to ORPs (PBR-ORPs). Though these analyses lack precision due to uncertainty, the results highlight the risks associated with implementing algal biofuel systems, as all scenarios examined were predicted to have Cost Growth, ranging from 1.2 to 1.8, and Plant Performance was projected as less than 50% of design performance for all cases. Second, the Framework the Evaluation of Biomass Energy Feedstocks (FEBEF) was used to assess the cost and environmental impacts of biodiesel produced from three algal production technologies. When these results were compared with ethanol from corn and biodiesel from soybeans, biodiesel from algae produced from the different technologies were estimated to be more expensive, suffered from low energy gains, and did not result in lower greenhouse gas emissions. To identify likely routes to making algal biofuels more competitive, a third study was undertaken. In this case, FEBEF was employed to examine pinch-points (defined as the most costly, energy consuming, greenhouse gas producing processes), in

  2. Estimation of algal and suspended sediment loads (singly and combined) using hyperspectral sensors and integrated mesocosm experiments

    SciTech Connect

    Schalles, J.F.; Schiebe, F.R.; Starks, P.J.

    1997-06-01

    Most remote sensing algorithms for materials in water are based on studies on natural waters with complex and variable optical properties, or of small indoor microcosm containers. We used sunlit, cylindrical, black mesocosm tanks (80m{sup 3}, 3 m depth) and a hyperspectral radiometer to examine reflectances of algal blooms and suspended kaolin white clay. In three integrated experiments, algae and clay levels were carefully manipulated: (1) Algal bloom water in one tank was pumped to a second which began with clear water, and clear make-up water was pumped to the first to obtain a well graded series (Chl. a = 0 - 62 {mu}g/L). (2) White, kaolin clay was added stepwise to clear water, resulting in an organic seston range of 0 - 40 mg/L. (3) Algal bloom water from a single source was divided between two tanks to establish Chi. a loads of 31 and 57 {mu}g/L. Then, identical additions of clay were made to both tanks to achieve a range of 0 - 72 mg/L inorganic matter while conserving the algal loads. The first experiment revealed a strong interplay between algal scattering and absorption. Pigment absorbance dominated below 510 nm, while increasing cell scattering in regions of low pigment activity caused green and NIR peaks to form near 560 and 700 nm. In spite of strong chlorophyll absorbance near 675 nm, this region had small reflectance increases with increased algae. In the second experiment, white clay had high albedo. At seston levels above 40 mg/L, green reflectance exceeded 50% and NIR reflectance at 800 nm exceeded 9%. In the third experiment, algal pigments strongly attenuated clay reflectance in a dose dependent manner, even at green wavelengths. Clay particles greatly amplified but also preserved algal reflectance patterns. Our findings affirm the importance of high spectral resolution at diagnostic wavelengths in turbid Case 2 coastal and inland waters.

  3. The Effects of Urbanization and Other Environmental Gradients on Algal Assemblages in Nine Metropolitan Areas across the United States

    USGS Publications Warehouse

    Coles, James F.; Bell, Amanda H.; Scudder, Barbara C.; Carpenter, Kurt D.

    2009-01-01

    The U.S. Geological Survey conducted studies from 2000 to 2004 to determine the effects of urbanization on stream ecosystems in nine major metropolitan study areas across the United States. Biological, chemical, and physical components of streams were assessed at 28 to 30 sites in each study area. Benthic algae were sampled to compare the degree to which algal assemblages correlated to urbanization, as characterized by an urban intensity index (UII), relative to other environmental gradients that function at either the watershed or reach scales. Ordination site scores were derived from principal components analyses of the environmental data to define environmental gradients at two spatial scales: (1) watershed-scale gradients that summarized (a) landscape modifications and (b) socioeconomic factors, and (2) reach-scale gradients that characterized (a) physical habitat and (b) water chemistry. Algal response was initially quantified by site scores derived from nonmetric multi-dimensional scaling ordinations of the algal assemblage data. The site scores were then correlated with a set of algal metrics of structure and function to help select specific indicators that would best represent changes in the algal assemblages and would infer ecological condition. The selected metrics were correlated to the UII and other environmental gradients. The results indicated that diatom-taxa in the assemblages were distinctly different across the nine study areas, likely due to physiographic differences across the country, but nevertheless, some algal metrics were applicable to all areas. Overall, the study results indicated that although the UII represented various landscape changes associated with urbanization across the country, the algal response was more strongly related to more specific factors generally associated with water quality measured within the stream reach.

  4. Differentiating the degradation dynamics of algal and terrestrial carbon within complex natural dissolved organic carbon in temperate lakes

    NASA Astrophysics Data System (ADS)

    Guillemette, François; McCallister, S. Leigh; Giorgio, Paul A.

    2013-07-01

    It has often been hypothesized that the dissolved organic carbon (DOC) pool of algal origin in lakes is more bioavailable than its terrestrial counterpart, but this hypothesis has seldom been directly tested. Here we test this hypothesis by tracking the production and isotopic signature of bacterial respiratory CO2 in 2 week lake water incubations and use the resulting data to reconstruct and model the bacterial consumption dynamics of algal and terrestrial DOC. The proportion of algal DOC respired decreased systematically over time in all experiments, suggesting a rapid consumption and depletion of this substrate. Our results further show that the algal DOC pool was used in proportions and at rates twice and 10 times as high as the terrestrial DOC pool, respectively. On the other hand, the absolute amount of labile terrestrial DOC was on average four times higher than labile algal DOC, accounting for almost the entire long-term residual C metabolism, but also contributing to short-term bacterial C consumption. The absolute amount of labile algal DOC increased with chlorophyll a concentrations, whereas total phosphorus appeared to enhance the amount of terrestrial DOC that bacteria could consume, suggesting that the degradation of these pools is not solely governed by their respective chemical properties, but also by interactions with nutrients. Our study shows that there is a highly reactive pool of terrestrial DOC that is processed in parallel to algal DOC, and because of interactions with nutrients, terrestrial DOC likely supports high levels of bacterial metabolism and CO2 production even in more productive lakes.

  5. Integrated Bacillus sp. immobilized cell reactor and Synechocystis sp. algal reactor for the treatment of tannery wastewater.

    PubMed

    Sekaran, G; Karthikeyan, S; Nagalakshmi, C; Mandal, A B

    2013-01-01

    The wastewater discharged from leather industries lack biodegradability due to the presence of xenobiotic compounds. The primary clarification and aerobic treatment in Bacillus sp. immobilized Chemo Autotrophic Activated Carbon Oxidation (CAACO) reactor removed considerable amount of pollution parameters. The residual untreated organics in the wastewater was further treated in algal batch reactor inoculated with Synechocystis sp. Sodium nitrate, K(2)HPO(4), MgSO(4).7H(2)O, NH(4)Cl, CaCl(2)·2H(2)O, FeCl(3) (anhydrous), and thiamine hydrochloride, rice husk based activated carbon (RHAC), immobilization of Bacillus sp. in mesoporous activated carbon, sand filter of dimensions diameter, 6 cm and height, 30 cm; and the CAACO reactor of dimensions diameter, 5.5 cm and height, 30 cm with total volume 720 ml, and working volume of 356 ml. In the present investigation, the CAACO treated tannery wastewater was applied to Synechocystis sp. inoculated algal batch reactor of hydraulic residence time 24 h. The BOD(5), COD, and TOC of treated wastewater from algal batch reactor were 20 ± 7, 167 ± 29, and 78 ± 16 mg/l respectively. The integrated CAACO system and Algal batch reactor was operated for 30 days and they accomplished a cumulative removal of BOD(5),COD, TOC, VFA and sulphide as 98 %, 95 %, 93 %, 86 %, and 100 %, respectively. The biokinetic constants for the growth of algae in the batch reactor were specific growth rate, 0.095(day(-1)) and yield coefficient, 3.15 mg of algal biomass/mg of COD destructed. The degradation of xenobiotic compounds in the algal batch reactor was confirmed through HPLC and FT-IR techniques. The integrated CAACO-Algal reactor system established a credible reduction in pollution parameters in the tannery wastewater. The removal mechanism is mainly due to co-metabolism between algae and bacterial species and the organics were completely metabolized rather than by adsorption. PMID:22528997

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

    USGS Publications Warehouse

    Honeyfield, Dale C.; Maloney, Kelly O.

    2015-01-01

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

  7. Life Cycle Analysis on Fossil Energy Ratio of Algal Biodiesel: Effects of Nitrogen Deficiency and Oil Extraction Technology

    PubMed Central

    Jian, Hou; Jing, Yang; Peidong, Zhang

    2015-01-01

    Life cycle assessment (LCA) has been widely used to analyze various pathways of biofuel preparation from “cradle to grave.” Effects of nitrogen supply for algae cultivation and technology of algal oil extraction on life cycle fossil energy ratio of biodiesel are assessed in this study. Life cycle fossil energy ratio of Chlorella vulgaris based biodiesel is improved by growing algae under nitrogen-limited conditions, while the life cycle fossil energy ratio of biodiesel production from Phaeodactylum tricornutum grown with nitrogen deprivation decreases. Compared to extraction of oil from dried algae, extraction of lipid from wet algae with subcritical cosolvents achieves a 43.83% improvement in fossil energy ratio of algal biodiesel when oilcake drying is not considered. The outcome for sensitivity analysis indicates that the algal oil conversion rate and energy content of algae are found to have the greatest effects on the LCA results of algal biodiesel production, followed by utilization ratio of algal residue, energy demand for algae drying, capacity of water mixing, and productivity of algae. PMID:26000338

  8. Life cycle analysis on fossil energy ratio of algal biodiesel: effects of nitrogen deficiency and oil extraction technology.

    PubMed

    Jian, Hou; Jing, Yang; Peidong, Zhang

    2015-01-01

    Life cycle assessment (LCA) has been widely used to analyze various pathways of biofuel preparation from "cradle to grave." Effects of nitrogen supply for algae cultivation and technology of algal oil extraction on life cycle fossil energy ratio of biodiesel are assessed in this study. Life cycle fossil energy ratio of Chlorella vulgaris based biodiesel is improved by growing algae under nitrogen-limited conditions, while the life cycle fossil energy ratio of biodiesel production from Phaeodactylum tricornutum grown with nitrogen deprivation decreases. Compared to extraction of oil from dried algae, extraction of lipid from wet algae with subcritical cosolvents achieves a 43.83% improvement in fossil energy ratio of algal biodiesel when oilcake drying is not considered. The outcome for sensitivity analysis indicates that the algal oil conversion rate and energy content of algae are found to have the greatest effects on the LCA results of algal biodiesel production, followed by utilization ratio of algal residue, energy demand for algae drying, capacity of water mixing, and productivity of algae. PMID:26000338

  9. The relationship between physical variables on topographically simple and complex reefs and algal assemblage structure beneath an Ecklonia radiata canopy

    NASA Astrophysics Data System (ADS)

    Toohey, Benjamin D.

    2007-01-01

    Limestone reefs in South-Western Australia range in topographic complexity at the 1-10 m scale from simple, flat, planar reef structures to topographically complex reefs with many rock walls, overhangs and channels. Algal assemblage structure is known to differ between topographically simple and complex reefs. This research assessed if differences in algal assemblage structure could be associated with the physical environment present on each reef type. Sampling of the physical environment and algal assemblage was carried out on simple, planar reefs and complex, rugose reefs. The physical environment described almost 80% of the algal assemblage structure under an Ecklonia radiata canopy. It was found that topographically simple reefs had greater sediment cover and water depth than adjacent reefs with more complex topography which had more downwelling light, stronger and more turbulent water motion and a greater range of substrate slopes. Greater variation in most physical variables on topographically complex reef shows a greater diversity of microenvironments on that reef type. It is argued that these differences in physical environment between reef types have a considerable influence on algal assemblages by altering key biological processes such as recruitment and interspecific competition.

  10. Effect of lake water on algal biomass and microbial community structure in municipal wastewater-based lab-scale photobioreactors.

    PubMed

    Krustok, I; Truu, J; Odlare, M; Truu, M; Ligi, T; Tiirik, K; Nehrenheim, E

    2015-08-01

    Photobioreactors are a novel environmental technology that can produce biofuels with the simultaneous removal of nutrients and pollutants from wastewaters. The aim of this study was to evaluate the effect of lake water inoculation on the production of algal biomass and phylogenetic and functional structure of the algal and bacterial communities in municipal wastewater-treating lab-scale photobioreactors. Inoculating the reactors with lake water had a significant benefit to the overall algal biomass growth and nutrient reduction in the reactors with wastewater and lake water (ratio 70/30 v/v). The metagenome-based survey showed that the most abundant algal phylum in these reactors was Chlorophyta with Scenedesmus being the most prominent genus. The most abundant bacterial phyla were Proteobacteria and Bacteroidetes with most dominant families being Sphingobacteriaceae, Cytophagaceae, Flavobacteriaceae, Comamonadaceae, Planctomycetaceae, Nocardiaceae and Nostocaceae. These photobioreactors were also effective in reducing the overall amount of pathogens in wastewater compared to reactors with wastewater/tap water mixture. Functional analysis of the photobioreactor metagenomes revealed an increase in relative abundance genes related to photosynthesis, synthesis of vitamins important for auxotrophic algae and decrease in virulence and nitrogen metabolism subsystems in lake water reactors. The results of the study indicate that adding lake water to the wastewater-based photobioreactor leads to an altered bacterial community phylogenetic and functional structure that could be linked to higher algal biomass production, as well as to enhanced nutrient and pathogen reduction in these reactors. PMID:25895091

  11. Water-quality parameters and benthic algal communities at selected streams in Minnesota, August 2000 - Study design, methods and data

    USGS Publications Warehouse

    Lee, K.E.

    2002-01-01

    This report describes the study design, sampling methods, and summarizes the physical, chemical, and benthic algal data for a component of the multiagency study that was designed to document diurnal water-quality measurements (specific conductance, pH, water temperature, and dissolved oxygen), benthic algal community composition and chlorophyll-a content, and primary productivity at 12 stream sites on 6 streams in Minnesota during August 2000. Specific conductance, pH, water temperature, dissolved oxygen concentrations and percent dissolved oxygen saturation measurements were made with submersible data recorders at 30 minute intervals for a period of 3-6 days during August 2000. Benthic algae collected from wood and rock substrate were identified and enumerated. Biovolume (volume of algal cells per unit area), density (number of cells per unit area), and chlorophyll-a content from benthic algae were determined. These data can be used as part of the multiagency study to develop an understanding of the relations among nutrient concentrations, algal abundance, algal community composition, and primary production and respiration processes in rivers of differing ecoregions in Minnesota.

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

    SciTech Connect

    J Murdock; W Dodds; J Reffner; D Wetzel

    2011-12-31

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

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

    PubMed

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

    2011-01-01

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

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

    PubMed Central

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

    2011-01-01

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

  15. Ocean acidification induces changes in algal palatability and herbivore feeding behavior and performance.

    PubMed

    Duarte, Cristian; López, Jorge; Benítez, Samanta; Manríquez, Patricio H; Navarro, Jorge M; Bonta, Cesar C; Torres, Rodrigo; Quijón, Pedro

    2016-02-01

    The effects of global stressors on a species may be mediated by the stressors' impact on coexisting taxa. For instance, herbivore-algae interactions may change due to alterations in algal nutritional quality resulting from high CO2 levels associated with ocean acidification (OA). We approached this issue by assessing the indirect effects of OA on the trophic interactions between the amphipod Orchestoidea tuberculata and the brown alga Durvillaea antarctica, two prominent species of the South-east Pacific coast. We predicted that amphipod feeding behavior and performance (growth rate) will be affected by changes in the palatability of the algae exposed to high levels (1000 ppm) of CO2. We exposed algae to current and predicted (OA) atmospheric CO2 levels and then measured their nutritive quality and amphipod preference in choice trials. We also assessed consumption rates separately in no-choice trials, and measured amphipod absorption efficiency and growth rates. Protein and organic contents of the algae decreased in acidified conditions and amphipods showed low preference for these algae. However, in the no-choice trials we recorded higher grazing rates on algae exposed to OA. Although amphipod absorption efficiency was lower on these algae, growth rates did not differ between treatments, which suggests the occurrence of compensatory feeding. Our results suggest that changes in algal nutritional value in response to OA induce changes in algal palatability and these in turn affect consumers' food preference and performance. Indirect effects of global stressors like OA can be equally or more important than the direct effects predicted in the literature. PMID:26453521

  16. Acid-Catalyzed Algal Biomass Pretreatment for Integrated Lipid and Carbohydrate-Based Biofuels Production

    DOE PAGESBeta

    Laurens, L. M. L.; Nagle, N.; Davis, R.; Sweeney, N.; Van Wychen, S.; Lowell, A.; Pienkos, P. T.

    2014-11-12

    One of the major challenges associated with algal biofuels production in a biorefinery-type setting is improving biomass utilization in its entirety, increasing the process energetic yields and providing economically viable and scalable co-product concepts. We demonstrate the effectiveness of a novel, integrated technology based on moderate temperatures and low pH to convert the carbohydrates in wet algal biomass to soluble sugars for fermentation, while making lipids more accessible for downstream extraction and leaving a protein-enriched fraction behind. We studied the effect of harvest timing on the conversion yields, using two algal strains; Chlorella and Scenedesmus, generating biomass with distinctive compositionalmore » ratios of protein, carbohydrate, and lipids. We found that the late harvest Scenedesmus biomass had the maximum theoretical biofuel potential at 143 gasoline gallon equivalent (GGE) combined fuel yield per dry ton biomass, followed by late harvest Chlorella at 128 GGE per ton. Our experimental data show a clear difference between the two strains, as Scenedesmus was more successfully converted in this process with a demonstrated 97 GGE per ton. Our measurements indicated a release of >90% of the available glucose in the hydrolysate liquors and an extraction and recovery of up to 97% of the fatty acids from wet biomass. Techno-economic analysis for the combined product yields indicates that this process exhibits the potential to improve per-gallon fuel costs by up to 33% compared to a lipids-only process for one strain, Scenedesmus, grown to the mid-point harvest condition.« less

  17. Physicochemical transformation and algal toxicity of engineered nanoparticles in surface water samples.

    PubMed

    Zhang, Luqing; Li, Jingyi; Yang, Kun; Liu, Jingfu; Lin, Daohui

    2016-04-01

    Most studies on the behavior and toxicity of engineered nanoparticles (NPs) have been conducted in artificial water with well-controlled conditions, which are dramatically different from natural waters with complex compositions. To better understand the fate and toxicity of NPs in the natural water environment, physicochemical transformations of four NPs (TiO2, ZnO, Ag, and carbon nanotubes (CNTs)) and their toxicities towards a unicellular green alga (Chlorella pyrenoidosa) in four fresh water and one seawater sample were investigated. Results indicated that water chemistry had profound effects on aggregation, dissolution, and algal toxicity of the NPs. The strongest homoaggregation of the NPs was associated with the highest ionic strength, but no obvious correlation was observed between the homoaggregation of NPs and pH or dissolved organic matter content of the water samples. The greatest dissolution of ZnO NPs also occurred in seawater with the highest ionic strength, while the dissolution of Ag NPs varied differently from ZnO NPs. The released Zn(2+) and especially Ag(+) mainly accounted for the algal toxicity of ZnO and Ag NPs, respectively. The NP-cell heteroagglomeration occurred generally for CNTs and Ag NPs, which contributed to the observed nanotoxicity. However, there was no significant correlation between the observed nanotoxicity and the type of NP or the water chemistry. It was thus concluded that the physicochemical transformations and algal toxicities of NPs in the natural water samples were caused by the combined effects of complex water quality parameters rather than any single influencing factor alone. These results will increase our knowledge on the fate and effects of NPs in the aquatic environment. PMID:26745398

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

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2012-01-01

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

  20. Red algal beds increase the condition of nekto-benthic fish

    NASA Astrophysics Data System (ADS)

    Ordines, Francesc; Bauzá, Marco; Sbert, Miquel; Roca, Pilar; Gianotti, Magdalena; Massutí, Enric

    2015-01-01

    The present study analysed the effect of three different benthic habitats, the maërl, Peyssonnelia red algal beds and sandy bottoms, on the condition of two nekto-benthic fish species: Serranus cabrilla and Trigloporus lastoviza. Sampling was conducted during the MEDITS 2010 and 2011 surveys around the Balearic Islands. The condition of the spawning females of both species was determined by using i) biochemical measurements of proteins and lipids in the muscle, liver and gonads, and ii) weight at length relationships based on eviscerated, liver, and gonad weights. Moreover, based on the total weight at length relationship, the mean somatic condition (SC) of the sexually inactive individuals of S. cabrilla and males of T. lastoviza was calculated. Lipid reserves were higher in the livers of S. cabrilla and T. lastoviza from the maërl beds. Additionally, S. cabrilla showed higher lipid reserves in the gonads both in the maërl and Peyssonnelia beds. The mean weights of the liver and gonads at a given individual length revealed the same pattern as the lipids, whereas the mean eviscerated weight was higher in the maërl beds but only for S. cabrilla. A positive correlation was detected between the SC and the biomass of the algal species characterizing the maërl beds for both S. cabrilla and T. lastoviza. The high habitat quality of the red algal beds off the Balearic Islands increased the condition of nekto-benthic fish. In oligotrophic areas, such as the archipelago, these "oases" could help fish to maintain healthy populations.

  1. A Novel Inducer of Roseobacter Motility Is Also a Disruptor of Algal Symbiosis

    PubMed Central

    Sule, Preeti

    2013-01-01

    Silicibacter sp. strain TM1040, a member of the Roseobacter clade, forms a symbiosis with unicellular phytoplankton, which is inextricably linked to the biphasic “swim or stick” lifestyle of the bacteria. Mutations in flaC bias the population toward the motile phase. Renewed examination of the FlaC− strain (HG1016) uncovered that it is composed of two different cells: a pigmented type, PS01, and a nonpigmented cell, PS02, each of which has an identical mutation in flaC. While monocultures of PS01 and PS02 had few motile cells (0.6 and 6%, respectively), coculturing the two strains resulted in a 10-fold increase in the number of motile cells. Cell-free supernatants from coculture or wild-type cells were fully capable of restoring motility to PS01 and PS02, which was due to increased fliC3 (flagellin) transcription, FliC3 protein levels per cell, and flagella synthesis. The motility-inducing compound has an estimated mass of 226 Da, as determined by mass spectrometry, and is referred to as Roseobacter Motility Inducer (RMI). Mutations affecting genes involved in phenyl acetic acid synthesis significantly reduced RMI, while defects in tropodithietic acid (TDA) synthesis had marginal or no effect on RMI. RMI biosynthesis is induced by p-coumaric acid, a product of algal lignin degradation. When added to algal cultures, RMI caused loss of motility, cell enlargement, and vacuolization in the algal cells. RMI is a new member of the roseobacticide family of troponoid compounds whose activities affect roseobacters, by shifting their population toward motility, as well as their phytoplankton hosts, through an algicidal effect. PMID:23161030

  2. Bacterial Community Structure Associated with a Dimethylsulfoniopropionate-Producing North Atlantic Algal Bloom

    PubMed Central

    González, José M.; Simó, Rafel; Massana, Ramon; Covert, Joseph S.; Casamayor, Emilio O.; Pedrós-Alió, Carlos; Moran, Mary Ann

    2000-01-01

    The bacteria associated with oceanic algal blooms are acknowledged to play important roles in carbon, nitrogen, and sulfur cycling, yet little information is available on their identities or phylogenetic affiliations. Three culture-independent methods were used to characterize bacteria from a dimethylsulfoniopropionate (DMSP)-producing algal bloom in the North Atlantic. Group-specific 16S rRNA-targeted oligonucleotides, 16S ribosomal DNA (rDNA) clone libraries, and terminal restriction fragment length polymorphism analysis all indicated that the marine Roseobacter lineage was numerically important in the heterotrophic bacterial community, averaging >20% of the 16S rDNA sampled. Two other groups of heterotrophic bacteria, the SAR86 and SAR11 clades, were also shown by the three 16S rRNA-based methods to be abundant in the bloom community. In surface waters, the Roseobacter, SAR86, and SAR11 lineages together accounted for over 50% of the bacterial rDNA and showed little spatial variability in abundance despite variations in the dominant algal species. Depth profiles indicated that Roseobacter phylotype abundance decreased with depth and was positively correlated with chlorophyll a, DMSP, and total organic sulfur (dimethyl sulfide plus DMSP plus dimethyl sulfoxide) concentrations. Based on these data and previous physiological studies of cultured Roseobacter strains, we hypothesize that this lineage plays a role in cycling organic sulfur compounds produced within the bloom. Three other abundant bacterial phylotypes (representing a cyanobacterium and two members of the α Proteobacteria) were primarily associated with chlorophyll-rich surface waters of the bloom (0 to 50 m), while two others (representing Cytophagales and δ Proteobacteria) were primarily found in deeper waters (200 to 500 m). PMID:11010865

  3. A unicellular algal virus, Emiliania huxleyi virus 86, exploits an animal-like infection strategy.

    PubMed

    Mackinder, Luke C M; Worthy, Charlotte A; Biggi, Gaia; Hall, Matthew; Ryan, Keith P; Varsani, Arvind; Harper, Glenn M; Wilson, William H; Brownlee, Colin; Schroeder, Declan C

    2009-09-01

    Emiliania huxleyi virus 86 (EhV-86) belongs to the family Phycodnaviridae, a group of viruses that infect a wide range of freshwater and marine eukaryotic algae. Phycodnaviridae is one of the five families that belong to a large and phylogenetically diverse group of viruses known as nucleocytoplasmic large dsDNA viruses (NCLDVs). To date, our understanding of algal NCLDV entry is based on the entry mechanisms of members of the genera Chlorovirus and Phaeovirus, both of which consist of non-enveloped viruses that 'inject' their genome into their host via a viral inner-membrane host plasma membrane fusion mechanism, leaving an extracellular viral capsid. Using a combination of confocal and electron microscopy, this study demonstrated for the first time that EhV-86 differs from its algal virus counterparts in two fundamental areas. Firstly, its capsid is enveloped by a lipid membrane, and secondly, EhV-86 enters its host via either an endocytotic or an envelope fusion mechanism in which an intact nucleoprotein core still encapsulated by its capsid is seen in the host cytoplasm. Real-time fluorescence microscopy showed that viral internalization and virion breakdown took place within the host on a timescale of seconds. At around 4.5 h post-infection, virus progeny were released via a budding mechanism during which EhV-86 virions became enveloped with host plasma membrane. EhV-86 therefore appears to have an infection mechanism different from that employed by other algal NCLDVs, with entry and exit strategies showing a greater analogy to animal-like NCLDVs. PMID:19474246

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

    PubMed Central

    Fujita, Kazuhiko; Okai, Takaaki; Hosono, Takashi

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  6. Insights into the evolution of vitamin B12 auxotrophy from sequenced algal genomes.

    PubMed

    Helliwell, Katherine E; Wheeler, Glen L; Leptos, Kyriacos C; Goldstein, Raymond E; Smith, Alison G

    2011-10-01

    Vitamin B(12) (cobalamin) is a dietary requirement for humans because it is an essential cofactor for two enzymes, methylmalonyl-CoA mutase and methionine synthase (METH). Land plants and fungi neither synthesize or require cobalamin because they do not contain methylmalonyl-CoA mutase, and have an alternative B(12)-independent methionine synthase (METE). Within the algal kingdom, approximately half of all microalgal species need the vitamin as a growth supplement, but there is no phylogenetic relationship between these species, suggesting that the auxotrophy arose multiple times through evolution. We set out to determine the underlying cellular mechanisms for this observation by investigating elements of B(12) metabolism in the sequenced genomes of 15 different algal species, with representatives of the red, green, and brown algae, diatoms, and coccolithophores, including both macro- and microalgae, and from marine and freshwater environments. From this analysis, together with growth assays, we found a strong correlation between the absence of a functional METE gene and B(12) auxotrophy. The presence of a METE unitary pseudogene in the B(12)-dependent green algae Volvox carteri and Gonium pectorale, relatives of the B(12)-independent Chlamydomonas reinhardtii, suggest that B(12) dependence evolved recently in these lineages. In both C. reinhardtii and the diatom Phaeodactylum tricornutum, growth in the presence of cobalamin leads to repression of METE transcription, providing a mechanism for gene loss. Thus varying environmental conditions are likely to have been the reason for the multiple independent origins of B(12) auxotrophy in these organisms. Because the ultimate source of cobalamin is from prokaryotes, the selective loss of METE in different algal lineages will have had important physiological and ecological consequences for these organisms in terms of their dependence on bacteria. PMID:21551270

  7. ATP and related purines stimulate motility, spatial congregation, and coalescence in red algal spores.

    PubMed

    Huidobro-Toro, Juan P; Donoso, Verónica; Flores, Verónica; Santelices, Bernabé

    2015-04-01

    Adenosine 5'-triphosphate (ATP) is a versatile extracellular signal along the tree of life, whereas cAMP plays a major role in vertebrates as an intracellular messenger for hormones, transmitters, tastants, and odorants. Since red algal spore coalescence may be considered analogous to the congregation process of social amoeba, which is stimulated by cAMP, we ascertained whether exogenous applications of ATP, cAMP, adenine, or adenosine modified spore survival and motility, spore settlement and coalescence. Concentration-response studies were performed with carpospores of Mazzaella laminarioides (Gigartinales), incubated with and without added purines. Stirring of algal blades released ADP/ATP to the cell media in a time-dependent manner. 10-300 μM ATP significantly increased spore survival; however, 1,500 μM ATP, cAMP or adenine induced 100% mortality within less than 24 h; the exception was adenosine, which up to 3,000 μM, did not alter spore survival. ATP exposure elicited spore movement with speeds of 2.2-2.5 μm · s(-1) . 14 d after 1,000 μM ATP addition, spore abundance in the central zone of the plaques was increased 2.7-fold as compared with parallel controls. Likewise, 1-10 μM cAMP or 30-100 μM adenine also increased central zone spore abundance, albeit these purines were less efficacious than ATP; adenosine up to 3,000 μM did not influence settlement. Moreover, 1,000 μM ATP markedly accelerated coalescence, the other purines caused a variable effect. We conclude that exogenous cAMP, adenine, but particularly ATP, markedly influence red algal spore physiology; effects are compatible with the expression of one or more membrane purinoceptor(s), discarding adenosine receptor participation. PMID:26986520

  8. Lithofacies distribution and reservoir heterogeneity within Pennsylvanian phylloid algal mounds, western Orogrande basin, New Mexico

    SciTech Connect

    Giles, K.A.; Soreghan, G.S.

    1996-12-31

    Pennsylvanian strata within the San Andres Mountains (western Orogrande basin) contain very well-developed phylloid algal bioherms, but these bioherms remain understudied owing to their location within the bounds of the U.S. Army White Sands Missile Range. The exposed Upper Pennsylvanian section within Hembrillo Canyon affords a three-dimensional view of mound structure, and thus an excellent opportunity for characterizing lithofacies distribution and reservoir heterogeneity that may prove useful for exploration/exploitation efforts in analogous petroliferous systems. The mounds are developed within a mixed carbonate-clastic shallow marine section punctuated by shoaling-upward cycles. Each mound site consists of a slack of individual biohermal growth events characterized by a subtidal wackestone initiation phase, core boundstone phase, and peritidal to subaerially exposed packstone/grainstone terminal phase. Individual biohermal growth events range up to 30 m in thickness; vertical stacking of these bioherms has produced aggregate mounds reaching up to 100 m in stratigraphic thickness and 300 m in diameter. Individual blohermal thicknesses decrease abruptly and markedly away from mound sites, and calcareous mudstones dominate in intermound regions. The controlling influences of paleogeography and glacioeustasy, respectively, produced the pronounced lateral and vertical heterogeneity characterizing these and analogous phylloid algal mound systems. Reservoirs within these systems are highly compartmentalized: wackestone initiation phases and peritidal to subaerial termination phases that envelope core facies may serve as porosity and permeability barriers that effectively partition the reservoir. Recognition of the scale, character, and probable controls on these lateral and vertical changes is important for effective exploration and exploitation in phylloid algal mound systems.

  9. Lithofacies distribution and reservoir heterogeneity within Pennsylvanian phylloid algal mounds, western Orogrande basin, New Mexico

    SciTech Connect

    Giles, K.A. ); Soreghan, G.S. )

    1996-01-01

    Pennsylvanian strata within the San Andres Mountains (western Orogrande basin) contain very well-developed phylloid algal bioherms, but these bioherms remain understudied owing to their location within the bounds of the U.S. Army White Sands Missile Range. The exposed Upper Pennsylvanian section within Hembrillo Canyon affords a three-dimensional view of mound structure, and thus an excellent opportunity for characterizing lithofacies distribution and reservoir heterogeneity that may prove useful for exploration/exploitation efforts in analogous petroliferous systems. The mounds are developed within a mixed carbonate-clastic shallow marine section punctuated by shoaling-upward cycles. Each mound site consists of a slack of individual biohermal growth events characterized by a subtidal wackestone initiation phase, core boundstone phase, and peritidal to subaerially exposed packstone/grainstone terminal phase. Individual biohermal growth events range up to 30 m in thickness; vertical stacking of these bioherms has produced aggregate mounds reaching up to 100 m in stratigraphic thickness and 300 m in diameter. Individual blohermal thicknesses decrease abruptly and markedly away from mound sites, and calcareous mudstones dominate in intermound regions. The controlling influences of paleogeography and glacioeustasy, respectively, produced the pronounced lateral and vertical heterogeneity characterizing these and analogous phylloid algal mound systems. Reservoirs within these systems are highly compartmentalized: wackestone initiation phases and peritidal to subaerial termination phases that envelope core facies may serve as porosity and permeability barriers that effectively partition the reservoir. Recognition of the scale, character, and probable controls on these lateral and vertical changes is important for effective exploration and exploitation in phylloid algal mound systems.

  10. Seasonal mercury levels in phytoplankton and their relationship with algal biomass in two dystrophic shield lakes

    SciTech Connect

    Kirkwood, A.E.; Chow-Fraser, P.; Mierle, G.

    1999-03-01

    This study focused on the seasonal dynamics of total Hg in the phytoplankton (living and dead) of two dystrophic shield lakes (Mouse and Ranger). Phytoplankton samples were taken from metalimnetic and hypolimnetic depths in the euphotic zone and were collected and analyzed using ultraclean techniques. In both lakes, phytoplankton Hg (PHYTO-Hg) levels (pg/L) in the metalimnion did not significantly change among dates over the season, although Ranger Lake exhibited significant differences between Hg values measured at the beginning and end of the season. In contrast, PHYTO-Hg significantly increased in the hypolimnia of both lakes by the end of the season. Combined influences of external Hg inputs, remineralization, phytoplankton sedimentation, and increased methylmercury production in the hypolimnia over the season may have contributed to these trends. A highly significant positive relationship existed between PHYTO-Hg levels and whole-water Hg levels, and the mean bioconcentration factor for Hg between the water column and phytoplankton was significantly higher in the hypolimnion compared to the metalimnion for both lakes. In most cases, parameters associated with algal biomass had significant positive correlations with PHYTO-Hg levels. Weight-specific PHYTO-Hg (pg/mg dry weight) varied significantly over the season, and there were interlake differences with respect to season trends. On the basis of these results, the authors recommend that the future sampling regimes include collection of phytoplankton at different limnetic depths through the season to account for spatial and temporal variations. Weight specific Hg levels in phytoplankton could not be explained well by the parameters tested, and the only significant regressions were with parameters reflecting algal biomass. This study provides in situ evidence of Hg accumulation in lake phytoplankton as a function of algal biomass on a seasonal basis and stresses the need to confirm these trends in other lake

  11. Quantifying Phycocyanin Concentration in Cyanobacterial Algal Blooms from Remote Sensing Reflectance-A Quasi Analytical Approach

    NASA Astrophysics Data System (ADS)

    Mishra, S.; Mishra, D. R.; Tucker, C.

    2011-12-01

    Cyanobacterial harmful algal blooms (CHAB) are notorious for depleting dissolved oxygen level, producing various toxins, causing threats to aquatic life, altering the food-web dynamics and the overall ecosystem functioning in inland lakes, estuaries, and coastal waters. Most of these algal blooms produce various toxins that can damage cells, tissues and even cause mortality of living organisms. Frequent monitoring of water quality in a synoptic scale has been possible by the virtue of remote sensing techniques. In this research, we present a novel technique to monitor CHAB using remote sensing reflectance products. We have modified a multi-band quasi analytical algorithm that determines phytoplankton absorption coefficients from above surface remote sensing reflectance measurements using an inversion method. In situ hyperspectral remote sensing reflectance data were collected from several highly turbid and productive aquaculture ponds. A novel technique was developed to further decompose the phytoplankton absorption coefficients at 620 nm and obtain phycocyanin absorption coefficient at the same wavelength. An empirical relationship was established between phycocyanin absorption coefficients at 620 nm and measured phycocyanin concentrations. Model calibration showed strong relationship between phycocyanin absorption coefficients and phycocyanin pigment concentration (r2=0.94). Validation of the model in a separate dataset produced a root mean squared error of 167 mg m-3 (phycocyanin range: 26-1012 mg m-3). Results demonstrate that the new approach will be suitable for quantifying phycocyanin concentration in cyanobacteria dominated turbid productive waters. Band architecture of the model matches with the band configuration of the Medium Resolution Imaging Spectrometer (MERIS) and assures that MERIS reflectance products can be used to quantify phycocyanin in cyanobacterial harmful algal blooms in optically complex waters.

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

    PubMed

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

    2010-04-15

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

  13. A resin-buffered nutrient solution for controlling metal speciation in the algal bottle assay.

    PubMed

    Verheyen, L; Merckx, R; Smolders, E

    2012-06-15

    Metal speciation in solution is uncontrolled during algal growth in the traditional algal bottle assay. A resin-buffered nutrient solution was developed to overcome this problem and this was applied to test the effect of chloride (Cl⁻) on cadmium (Cd) uptake. Standard nutrient solution was enriched with 40 mM of either NaNO₃ or NaCl, and was prepared to contain equal Cd²⁺ but varying dissolved Cd due to the presence of CdCl(n)(2-n) complexes. Both solutions were subsequently used in an algal assay in 100 mL beakers that contained only the solution (designated "-R") or contained the solution together with a cation exchange sulfonate resin (2 g L⁻¹, designated "+R") as a deposit on the bottom of the beaker. Pseudokirchneriella subcapitata was grown for 72 h (1.4 × 10⁵-1.4 × 10⁶ cells mL⁻¹) in stagnant solution and shaken three times a day. Growth was unaffected by the presence of the resin (p>0.05). The Cd concentrations in solution of the -R devices decreased with 50-58% of initial values due to Cd uptake. No such changes were found in the +R devices or in abiotic controls. Cd uptake was unaffected by either NaNO₃ or NaCl treatment in the +R device, confirming that Cd²⁺ is the preferred Cd species in line with the general concept of metal bioavailability. In contrast, Cd uptake in the -R devices was two-fold larger in the NaCl treatment than in the NaNO₃ treatment (p<0.001), suggesting that CdCl(n)(2-n) complexes are bioavailable in this traditional set-up. However this bioavailability is partially, but not completely, an apparent one, because of the considerable depletion of solution ¹⁰⁹Cd in this set-up. Resin-buffered solutions are advocated in the algal bottle assay to control trace metal supply and to better identify the role of metal complexes on bioavailability. PMID:22447105

  14. Algal toxin impairs sea lion memory and hippocampal connectivity, with implications for strandings.

    PubMed

    Cook, Peter F; Reichmuth, Colleen; Rouse, Andrew A; Libby, Laura A; Dennison, Sophie E; Carmichael, Owen T; Kruse-Elliott, Kris T; Bloom, Josh; Singh, Baljeet; Fravel, Vanessa A; Barbosa, Lorraine; Stuppino, Jim J; Van Bonn, William G; Gulland, Frances M D; Ranganath, Charan

    2015-12-18

    Domoic acid (DA) is a naturally occurring neurotoxin known to harm marine animals. DA-producing algal blooms are increasing in size and frequency. Although chronic exposure is known to produce brain lesions, the influence of DA toxicosis on behavior in wild animals is unknown. We showed, in a large sample of wild sea lions, that spatial memory deficits are predicted by the extent of right dorsal hippocampal lesions related to natural exposure to DA and that exposure also disrupts hippocampal-thalamic brain networks. Because sea lions are dynamic foragers that rely on flexible navigation, impaired spatial memory may affect survival in the wild. PMID:26668068

  15. Limnology of Oneida Lake with emphasis on factors contributing to algal blooms

    USGS Publications Warehouse

    Greeson, Phillip E.

    1971-01-01

    Oneida Lake is a naturally eutrophic lake that has existed for about 10,500 years. It has been in a eutrophic state for at least 350 years, and the geochemically derived dissolved materials entering the lake from the drainage basin are of sufficient quantity (449,700 tones per year) to support annual algal blooms. The greatest amount of the dissolved materials (72 percent) comes from the southern tributaries to the lake, of which Chittenango Creek carries the largest load of almost all major chemical substances. The stream contributes 37 percent of all dissolved solids entering the lake. Ground water is negligible in both the water and the nutrient budgets.

  16. A multispectral analysis of algal bloom in the Gulf of Mexico

    NASA Technical Reports Server (NTRS)

    Johnson, W. R.; Norris, D. R.

    1977-01-01

    Skylab multispectral scanner data acquired on January 21, 1974, were used to study the spectral characteristics of an algal bloom in the Gulf of Mexico west of Fort Myers, Florida. Radiance profiles of the water and algae were prepared with data from ten bands of the S192 scanner covering the spectral range from .42 to 2.35 micrometers. The high spectral response in the near-infrared spectral bands implies a possible classification and discrimination parameter for detection of blooms of phytoplankton concentrations such as the so-called red tides of Florida.

  17. Application of a pulsed laser for measurements of bathymetry and algal fluorescence.

    NASA Technical Reports Server (NTRS)

    Hickman, G. D.; Hogg, J. E.; Friedman, E. J.; Ghovanlou, A. H.

    1973-01-01

    The technique of measuring water depths with an airborne pulsed dye laser is studied, with emphasis on the degrading effect of some environmental and operational parameters on the transmitted and reflected laser signals. Extrapolation of measurements of laser stimulated fluorescence, performed as a function of both the algal cell concentration and the distance between the algae and the laser/receiver, indicate that a laser system operating from a height of 500 m should be capable of detecting chlorophyll concentrations as low as 1.0 mg/cu m.-

  18. Design and Implementation of Harmful Algal Bloom Diagnosis System Based on J2EE Platform

    NASA Astrophysics Data System (ADS)

    Guo, Chunfeng; Zheng, Haiyong; Ji, Guangrong; Lv, Liang

    According to the shortcomings which are time consuming and laborious of the traditional HAB (Harmful Algal Bloom) diagnosis by the experienced experts using microscope, all kinds of methods and technologies to identify HAB emerged such as microscopic images, molecular biology, characteristics of pigments analysis, fluorescence spectra, inherent optical properties, etc. This paper proposes the design and implementation of a web-based diagnosis system integrating the popular methods for HAB identification. This system is designed with J2EE platform based on MVC (Model-View-Controller) model as well as technologies such as JSP, Servlets, EJB and JDBC.

  19. NMR imaging of heavy metal absorption in alginate, immobilized cells, and kombu algal biosorbents.

    PubMed

    Nestle, N F; Kimmich, R

    1996-09-01

    In this contribution, an NMR imaging study of heavy metal absorption in alginate, immobilized-cell biosorbents, and kombu (Laminaria japonica) algal biomass is presented. This method provides the good possibility of directly monitoring the time evolution of the spatial distribution of the ions in the materials. From these results, we demonstrate that rare earth ions are absorbed with a steep reaction front that can be described very well with a modified shrinking core model, while copper ions are absorbed with a more diffuse front. PMID:18629817

  20. Remote sensing of algal blooms by aircraft and satellite in Lake Erie and Utah Lake

    NASA Technical Reports Server (NTRS)

    Strong, A. E.

    1974-01-01

    During late summer, when the surface waters of Lake Erie reach their maximum temperature, an algal bloom is likely to develop. Such phenomena, which characterize eutrophic conditions, have been noticed on other shallow lakes using the Earth Resources Technology Satellite (ERTS-1). The concentration of the algae into long streamers provides additional information on surface circulations. To augment the ERTS Multispectral Scanner Subsystem data of Lake Erie, an aircraft was used to obtain correlative thermal-IR and additional multiband photographs. A large bloom of Aphanizomenon flos-aquae observed in Utah Lake together with recent bloom history in Lake Erie is used to verify the Great Lakes bloom.