Spatial structure of a subtidal macrobenthic community in the Bay of Veys (western Bay of Seine, English Channel)

The spatial distribution of the muddy fine sand community from the Bay of Veys (western English Channel) were investigated during spring and autumn 1997. A grid of 55 and 54 sites was sampled in March and October, respectively, using two replicates per site of a Hamon grab (0.25 m²) for macrofauna collection and an additional one for sediment analysis. A total of 172 species were sampled with a dominance of polychaetes, followed by crustaceans and bivalves. The species richness and abundance show low temporal changes despite higher values in October than in March. In March, the mean abundance was 165 ind. 0.5 m⁻²; in October, the mean abundance was 212 ind. 0.5 m⁻². Four assemblages from the Abra alba-Pectinaria koreni community were identified corresponding to a bathymetric and sedimentary gradient from muddy fine sands with high levels of fine particles in shallow water to fine sands in deeper water. The discussion focuses on factors prevailing on the spatial structure of sandy communities in the English Channel.     

Isolation and Characterization of Highly Polymorphic Microsatellites from the Polychaete Pectinaria koreni

We report on the isolation of dinucleotide microsatellites from the polychaete Pectinaria koreni using (GT)₁₀ and (CT)₁₀ olignonucleotide probes. Compound and particularly imperfect microsatellites are predominant in this species. In most cases the associated element is (AT)_n leading to AT microsatellites being the most frequent class after GT repeats. Obtaining single-copy polymerase chain reaction products in the expected size range proved to be difficult, and only 24% of the primer pairs tested produced polymorphic single-locus markers. We obtained five highly variable loci with 16 to 41 alleles and an observed heterozygosity ranging from 0.29 to 0.81. Amplifications have also been obtained from the earliest postlarval stage. These highly informative markers will allow studies of the population structure of P. koreni at fine spatial and temporal scales. Received March 19, 1999; accepted September 10, 1999.     

Die Biomasse mariner Makrobenthos-Gesellschaften im Einflußbereich der Klärschlammverklappung vor der Elbemündung

The macrofauna of a dumping area in the eastern part of the German Bight (North Sea) was investigated in July, August and November, 1978 at five stations situated on a transect including central and peripheral areas of the dumping region. Abundance and biomass (ash free dry weight) of the macrofauna and its variation from July to November were analysed as well as the biomass of different taxa. Molluscs dominated over polychaetes, crustaceans and echinoderms. A positive correlation seemed to exist between mud content and biomass at the peripherally situated stations. In the central sewage sludge area, however, the biomass values were reduced. In late autumn the biomass decreased in the entire area due to the death ofDiastylis rathkei, Abra alba andPectinaria koreni. These species were replaced by the molluscNucula turgida and polychaeteNephtys hombergii. In autumn the biomass values also showed a distinct minimum at the central stations.     

Inter- and intraspecific variability in the chemical composition of the mineral phase of cements from several tube-building polychaetes

Several species of marine polychaetes reside in individual protective tubes. These tubes may be agglomerated in patches of varied sizes with very high densities, or form massive reef-like mounds which can be stretch over several kilometers. These polychaetes can thus be considered as the most important building organisms after corals in coastal environments. We especially focused on several species belonging to the families of Sabellariidae, Terrebeliidae and Pectinariidae. Tubes grains are glued together with biomineralized cement secreted from a building organ connected to specialized glands. Different methods of micro-analysis were used to analyze the biomineral components of these cements for four varyingly gregarious tube-building polychaetes: Lanice conchilega, Pectinaria koreni, Sabellaria alveolata and Phragmatopoma caudata. The aim of this study is to describe and compare the inter- and the intraspecific variability in the main biomineral components of cement at local, regional and continental scales. Scanning Electron Microscopy confirms an identical structure of the cement within species of Sabellariidae in Europe and America. Electron Probe Micro-Analysis (EPMA) confirms the presence of calcium, phosphorus, and magnesium plus traces of manganese in all cements, with varying concentrations of these elements at different locations for the same species or for different species at the same location. Finally, our dataset is compared with previous studies from literature.     

Adsorption of Rhodococcus Strain GIN-1 (NCIMB 40340) on Titanium Dioxide and Coal Fly Ash Particles

Rhodococcus strain GIN-1 (NCIMB 40340) can be used to enrich and isolate a titanium-rich fraction from coal fly ash. The gram-positive bacterium was isolated by its ability to adhere strongly and rapidly to suspended particles of pure titanium dioxide or coal fly ash. Adsorption depends on the salt concentration and occurs in seawater. Lowering of the salt concentration or washing of particles with pure water did not, however, cause desorption of the bacteria from TiO₂ particles; this was achieved by strong alkaline treatment or combined treatment with sodium dodecyl sulfate and urea but not with dilute acids, alcohols, or cationic or nonionic detergents. The bacterium exhibits higher affinity towards oxides of Ti and Zn than to other oxides with similar distribution of particle size. Moreover, it adheres much faster to TiO₂ than to magnetite (Fe₃O₄) or Al₂O₃. After about 1 min, more than 85% of the cells were adsorbed on TiO₂, compared with adsorption of only 10 and 8% to magnetite and Al₂O₃, respectively. Adsorption of the bacteria on TiO₂ occurs over a pH range of 1.0 to 9.0 and at temperatures from 4 to over 80°C. Scanning electron microscopy combined with X-ray analysis revealed preferential adherence of the bacterium to coal ash particles richer in Ti. Stronger adhesion to TiO₂ was also demonstrated in the translocation of bacteria, preadsorbed on magnetite, to TiO₂ particles. The temporary co-adhesion to magnetite and TiO₂ was exploited for the design of a prototype biomagnetic separation process in which bacterial cells serve as an adhesive mediator between magnetite and TiO₂ particles in a mixture of Al, Si, and Ti oxides that simulates their proportion in the ash.     

Development of a Laboratory-Scale Leaching Plant for Metal Extraction from Fly Ash by Thiobacillus Strains

Semicontinuous biohydrometallurgical processing of fly ash from municipal waste incineration was performed in a laboratory-scale leaching plant (LSLP) by using a mixed culture of Thiobacillus thiooxidans and Thiobacillus ferrooxidans. The LSLP consisted of three serially connected reaction vessels, reservoirs for a fly ash suspension and a bacterial stock culture, and a vacuum filter unit. The LSLP was operated with an ash concentration of 50 g liter⁻¹, and the mean residence time was 6 days (2 days in each reaction vessel). The leaching efficiencies (expressed as percentages of the amounts applied) obtained for the economically most interesting metal, Zn, were up to 81%, and the leaching efficiencies for Al were up to 52%. Highly toxic Cd was completely solubilized (100%), and the leaching efficiencies for Cu, Ni, and Cr were 89, 64, and 12%, respectively. The role of T. ferrooxidans in metal mobilization was examined in a series of shake flask experiments. The release of copper present in the fly ash as chalcocite (Cu₂S) or cuprite (Cu₂O) was dependent on the metabolic activity of T. ferrooxidans, whereas other metals, such as Al, Cd, Cr, Ni, and Zn, were solubilized by biotically formed sulfuric acid. Chemical leaching with 5 N H₂SO₄ resulted in significantly increased solubilization only for Zn. The LSLP developed in this study is a promising first step toward a pilot plant with a high capacity to detoxify fly ash for reuse for construction purposes and economical recovery of valuable metals.     

Formation of reactive oxygen species in rat epithelial cells upon stimulation with fly ash

Fly ash was used as a model for ambient particulate matter which is under suspicion to cause adverse pulmonary health effects. The fly ash was pre-sized and contained only particles < 20 microm including an ultrafine fraction (< 100 nm) that contributed 31% to the particle number. In our study, we investigated the influence of fly ash on the promotion of early inflammatory reactions like the formation of reactive oxygen species (ROS) in rat lung epithelial cells (RLE-6TN). Furthermore, we determined the formation of nitric oxide (NO). The cells show a clear dose-response relationship concerning the formation of ROS with regard to the mass of particles applied. Lipopolysaccharide (LPS) added as a co-stimulus did not increase the formation of ROS induced by fly ash. Furthermore, in LPS (0.1 microg/ml) and tumour necrosis factor-alpha (TNF-alpha; 1 ng/ml) pre-treated cells no increase in reactive oxygen species comparable to fly ash alone is observable. In presence of the metal chelator, desferrioxamine (DFO), ROS formation can be significantly reduced. Neither fly ash nor LPS induced a significant NO release in RLE-6TN cells.     

Treatment with Algae Extracts Promotes Flocculation, and Enhances Growth and Neutral Lipid Content in Nannochloropsis oculata—a Candidate for Biofuel Production

Marine microalgae represent a potentially valuable feedstock for biofuel production; however, large-scale production is not yet economically viable. Optimisation of productivity and lipid yields is required and the cost of biomass harvesting and dewatering must be significantly reduced. Microalgae produce a wide variety of biologically active metabolites, many of which are involved in inter- and intra-specific interactions (the so-called infochemicals). The majority of infochemicals remain unidentified or uncharacterised. Here, we apply known and candidate (undefined extracts) infochemicals as a potential means to manipulate the growth and lipid content of Nannochloropsis oculata—a prospective species for biofuel production. Five known infochemicals (β-cyclocitral, trans,trans-2,4-decadienal, hydrogen peroxide, norharman and tryptamine) and crude extracts prepared from Skeletonema marinoi and Dunaliella salina cultures at different growth stages were assayed for impacts on N. oculata over 24?h. The neutral lipid content of N. oculata increased significantly with exposure to three infochemicals (β-cyclocitral, decadienal and norharman); however the effective concentrations affected a significant decrease in growth. Exposure to particular crude extracts significantly increased both growth and neutral lipid levels. In addition, water-soluble extracts of senescent S. marinoi cultures induced a degree of flocculation in the N. oculata. These preliminary results indicate that artificial manipulation of N. oculata cultures by application of algae infochemicals could provide a valuable tool towards achieving economically viable large-scale algae biofuel production.     

Hexavalent chromium bioreduction and chemical precipitation of sulphate as a treatment of site-specific fly ash leachates

Most of the power generation globally is by coal-fired power plants resulting in large stockpiles of fly ash. The trace elements associated with the ash particles are subjected to the leaching effects of precipitation which may lead to the subsequent contamination of surface and groundwater systems. In this study, we successfully demonstrate an efficient and sustainable dual treatment remediation strategy for the removal of high levels of Cr⁶⁺ and SO₄ ^2? introduced by fly ash leachate generated by a power station situation in Mpumalanga, South Africa. The treatment consisted of a primary fixed-bed bioreactor kept at a reduction potential for Cr⁶⁺ reduction. Metagenome sequencing clearly indicated a diverse bacterial community containing various bacteria, predominantly of the phylum Proteobacteria which includes numerous species known for their ability to detoxify metals such as Cr⁶⁺. This was followed by a secondary BaCO₃/dispersed alkaline substrate column for SO₄ ^2? removal. The combination of these two systems resulted in the removal of 99% Cr⁶⁺ and 90% SO₄ ^2?. This is the first effective demonstration of an integrated system combining a biological and chemical strategy for the remediation of multi-contaminants present in fly ash leachate in South Africa.     

Impact of fly ash content and fly ash transportation distance on embodied greenhouse gas emissions and water consumption in concrete

Background, aim and scope  

Fly ash, a by-product of coal-fired power stations, is substituted for Portland cement to improve the properties of concrete and reduce the embodied greenhouse gas (GHG) emissions. Much of the world’s fly ash is currently disposed of as a waste product. While replacing some Portland cement with fly ash can reduce production costs and the embodied emissions of concrete, the relationship between fly ash content and embodied GHG emissions in concrete has not been quantified. The impact of fly ash content on embodied water is also unknown. Furthermore, it is not known whether a global trade in fly ash for use in concrete is feasible from a carbon balance perspective, or if transport over long distances would eliminate any CO₂ savings. This paper aims to quantify GHG emissions and water embodied in concrete (f′_c = 32 MPa) as a function of fly ash content and to determine the critical fly ash transportation distance, beyond which use of fly ash in concrete increases embodied GHG emissions.     

Suitability of Brahmi (Bacopa monnieri L.) cultivation on fly ash-amended soil for better growth and oil content

Abstract

Sustainable application of fly ash and its management in agriculture is a major challenge nowadays. A pot culture experiment was conducted to find out the most suitable level of fly ash application for soil amendments that can improve the plant growth and productivity of Brahmi (Bacopa monnieri L.). After growing seedlings of B. monnieri under different levels of fly ash for 90?days, a significant increase in plant biomass, essential oil content and tolerance index (more than 100%) was observed under 25% of fly ash amended soil in comparison to garden soil and higher fly ash treatments. Leaf chlorophyll content and photosynthetic parameters were remained unchanged under 25% of fly ash as compared to seedlings grown on garden soil. However, these parameters were significantly declined under higher concentrations of fly ash treatments. Higher levels of fly ash caused oxidative damage and the induction of some antioxidative enzymes activities in B. monnieri indicates its capability to endure oxidative stress tolerance. Overall, our study showed that 25% of fly ash can be used as soil amendment for cultivation of B. monnieri L. leading to enhance plant biomass and essential oil production.     

Effect of fly ash inhalation on biochemical and histomorphological changes in rat lungs

Effect of respirable fly ash particles inhalation on lungs of rats was investigated by exposing them to respirable aerosols of size classified power plant fly ash at average concentrations of up to 14.4 +/- 1.77 mg/m3 for 4 hr/day for 28 consecutive days. A remarkable increase was found in blood eosinophil counts of fly ash exposed animals. Biochemical indicators of pulmonary damage viz. lactate dehydrogenase (cytoplasmic enzyme used as a measure of cell injury), gamma-glutamyl transferase (Clara cell damage) and alkaline phosphatase (potential measure of Type 11 cell secretions) in broncho alveolar lavage fluid (BALF) of fly ash exposed group showed significant elevation. Clumping of fly ash particles in the lungs was observed as evidenced by fly ash ladened macrophage accumulation in the alveolar region. The results suggest a damage, local inflammation and remodelling of lung as indicated by hypertrophy and hyperplasia. These changes reflect the toxic effects of the fly ash inhalation.     

Distribution of third-stage Dirofilaria roemeri (Nematoda: Filarioidea) in the tissues of tabanidae (Diptera)

The distribution of third-stage D. roemeri in its tabanid intermediate host was observed in histological sections of naturally infected Dasybasis oculata and Tabanus parvicallosus. Larvae invade the brain, eye, nerve cord, muscles of the mouthparts, horizontal and indirect flight muscles, fat body, hind gut and gonad of flies. Third-stage D. roemeri migrate from the abdomen via the haemocoelic spaces of the thorax to the head of the fly. Evidence suggests that larvae escape from the intermediate host by rupturing the tip of the labrum or the labro-epipharyngeal membranes. Injury was observed in the eye, nerve cord and musculature. There was no evidence that the parasite had a detrimental effect on the host and tabanids showed no response to the presence of filarioids. Species of Dasybasis and Tabanus acting as intermediate host of D. roemeri in nature epitomize the concept of a ‘good’ host.     

Soil properties and turf growth on a sandy soil amended with fly ash

Field lysimeters of a sandy soil were amended to a depth of 100 mm with four rates (0, 5, 10 and 20%, wt/wt) of fly ash, and effects on soil water content, nutrient leaching, turf growth and nutrition, and uptake of trace elements by turf were assessed. Measurements were taken for 70 days for lysimeters either planted with rhizomes of Cynodon dactylon(L.) Pers., cv. `Wintergreen', or left bare. When irrigated daily, soil water content increased progressively with increasing rates of fly ash and leachate volumes were decreased by 17–52% for lysimeters containing fly ash amended soil. Fertiliser was applied equivalent to 28.4 g N m<sup>–2</sup> and 10.3 g P m<sup>–2</sup> for the entire 70 days (including pre-plant application). Macronutrient concentrations in leaf tissue were within levels regarded as sufficient. Total dry mass (root plus shoot) decreased when fertiliser application rates were reduced by 25%, irrespective of fly ash treatment. In `bare' lysimeters containing fly ash amended soil, cumulative leaching of NO₃ ^–, NH₄ ⁺and P were 0.32–0.88 of the values in non-amended soil. When planted with turf, leaching of those nutrients was minimal (equivalent to 3% of total N applied) and leaching loses did not differ among fly ash rates. Extractable soil P levels were increased 2.5–4.5-fold in the fly ash amended zone, compared with non-amended soil. Root mass in the top 100 mm was 1.2–1.5-fold larger for turf in fly ash amended soil, compared to non-amended soil. The Se concentrations were higher in leaf tissue grown in fly ash amended soil (being at most 0.63 g g^–1), but there was no effect of fly ash amended soil on As, Ba, B, Cd, Co, Cr, Cu, Pb, Hg, Mn, Ni, Ag or Zn in leaf tissues. Thus, fly ash amendment may be a suitable management option for turf culture on sandy soils, since fly ash improved soil water holding capacity and root growth in the amended zone.     

Effects of nitrogen supplementation of the culture medium on the growth, total lipid content and fatty acid profiles of three microalgae (Tetraselmis subcordiformis, Nannochloropsis oculata and Pavlova viridis)

To improve the properties of microalgae as sources for biodiesel production, three microalgae (Tetraselmis subcordiformis SHOU-S05, Nannochloropsis oculata SHOU-S14 and Pavlova viridis SHOU-S16) were cultured in media supplemented with different amounts of nitrogen (0, 0.22, 0.44, 0.88 and 1.76 mmol N·L^?1). The growth, total lipid contents, lipid classes and fatty acid profiles of the three microalgae were assayed after 10 days of cultivation. The results indicated that the specific growth rates of T. subcordiformis, N. oculata and P. viridis were lowest (0.014, 0.033 and 0.018, respectively) in the treatments without nitrogen supplementation and increased significantly with increasing nitrogen supplementation. The microalgae treated with 0.22 mmol N·L^?1 had the highest total lipid contents, which were 29.77, 35.85 and 32.10 % in T. subcordiformis, N. oculata and P. viridis, respectively. The total lipid contents as well as the proportions of neutral lipid in the three microalgae decreased significantly with increasing nitrogen supplementation between 0.22 and 1.76 mmol N·L^?1. The fatty acid profiles of the three microalgae were significantly different. The obvious characteristic of the fatty acid profile of T. subcordiformis was a high amount (17.68–22.22 %) of 18:3n3. However, EPA (C20:5n3) and C16 fatty acids were significantly high in N. oculata and P. viridis, respectively. N. oculata and P. viridis accumulated more 16-carbon fatty acids and fewer polyunsaturated fatty acids in nitrogen-limited media. It is therefore suggested that a limited nitrogen treatment is effective for improving the properties of P. viridis and N. oculata as sources for biodiesel.     

Purple Chromoprotein Gene Serves as a New Selection Marker for Transgenesis of the Microalga Nannochloropsis oculata

Among the methods used to screen transgenic microalgae, antibiotics selection has raised environmental and food safety concerns, while the observation of fluorescence proteins could be influenced by the endogenous fluorescence of host chloroplasts. As an alternative, this study isolated the purple chromoprotein (CP) from Stichodacyla haddoni (shCP). A plasmid in which shCP cDNA is driven by a heat-inducible promoter was linearized and electroporated into 2.5×10⁸ protoplasts of Nannochloropsis oculata. Following regeneration and cultivation on an f/2 medium plate for two weeks, we observed 26 colonies that displayed a slightly dark green coloration. After individually subculturing and performing five hours of heat shock at 42°C, a dark brown color was mosaically displayed in five of these colonies, indicating that both untransformed and transformed cells were mixed together in each colony. To obtain a uniform expression of shCP throughout the whole colony, we continuously isolated each transformed cell that exhibited brown coloration and subcultured it on a fresh plate, resulting in the generation of five transgenic lines of N. oculata which stably harbored the shCP gene for at least 22 months, as confirmed by PCR detection and observation by the naked eye. As shown by Western blot, exogenous shCP protein was expressed in these transgenic microalgae. Since shCP protein is biodegradable and originates from a marine organism, both environmental and food safety concerns have been eliminated, making this novel shCP reporter gene a simple, but effective and ecologically safe, marker for screening and isolating transgenic microalgae.     

Gypsum amendment to soil can reduce selenium uptake by alfalfa grown in the presence of coal fly ash

Experiments in the field and greenhouse were conducted in the presence of coal fly ash to determine whether gypsum can reduce Se concentration in alfalfa (Medicago sativa L.). In the field experiment, conducted at a coal fly ash landfill, 11.2 t ha^-1 gypsum was applied to soil as a top dressing to test the effect of gypsum in reducing selenium (Se) concentration in aboveground plant tissue. There were four treatment combinations of gypsum over a two year period, 1990 and 1991: (0, 0), (0, 11.2) (11.2, 0) and (11.2, 11.2). In 1991, the Se concentration was lower in alfalfa grown with gypsum regardless of whether the gypsum was applied in both years or in only one year, indicating that the effect of gypsum application in the first year persisted into the second year. Since there was no increase in aboveground biomass with added gypsum, differences in Se concentration reflect a competitive interaction between S and Se. In the greenhouse experiment, 12 soil treatments were tested: three levels of fly ash (0, 10 and 20%) in combination with each of four levels of gypsum (0, 2.5, 5, and 7.5%). The Se concentration in alfalfa grown in 10% fly ash declined linearly with increasing gypsum dose, resulting in a reduction in Se concentration of 0.04±0.02 μg g^-1 for each 1% gypsum added for the first harvest and 0.06±0.03 μg g^-1 for each 1% gypsum added in the second harvest. Based on these results, gypsum may prove useful as a management tool to reduce the uptake of Se by plants growing on coal fly ash landfills. ei]H Lambers     

Freeze-dried microalgae of Nannochloropsis oculata improve soybean oil's oxidative stability

Marine microalga Nannochloropsis oculata possesses nutrients valuable for human health. In this study, we added freeze-dried N. oculata powder to soybean oil and observed a remarkable inhibition in oil oxidation. The amount of microalgae powder added was positively correlated to the increase in oil stability. The addition of 5.0 % (w/w) microalgae powder increased the oil stability index (OSI) values of soybean oil more than twofold at the tested temperatures 120 and 130 °C. N. oculata contains high levels of both phenolic compounds and α-tocopherols that could be the contributors to such an increase of the OSI. Two methods were conducted to assay the active ingredients released from microalgae: one employed three solvent systems to extract the microalgae and the other was the soybean oil added with microalgae. Analyses of free radical scavenging and reducing power suggested that the phenolic compounds dominated the antioxidation activities in soybean oil when it was infused with the microalgae powder. Our results suggest that N. oculata could potentially be used as an additive in cooking oil to increase the shelf life and nutritional value of the oil and to reduce the production of free radicals from lipid oxidation when the oil is used at high-temperature cooking processes.