Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
1.
Proc Biol Sci ; 288(1961): 20211712, 2021 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-34666520

RESUMO

Coral reefs are experiencing declines due to climate change and local human impacts. While at a local scale these impacts induce biodiversity loss and shifts in community structure, previous biogeographical analyses recorded consistent taxonomic structure of fish communities across global coral reefs. This suggests that regional communities represent a random subset of the global species and traits pool, whatever their species richness. Using distributional data on 3586 fish species and latest advances in species distribution models, we show marked gradients in the prevalence of size classes and diet categories across the biodiversity gradient. This divergence in trait structure is best explained by reef isolation during past unfavourable climatic conditions, with large and piscivore fishes better represented in isolated areas. These results suggest the risk of a global community re-organization if the ongoing climate-induced reef fragmentation is not halted.


Assuntos
Antozoários , Recifes de Corais , Animais , Biodiversidade , Mudança Climática , Peixes , Prevalência
2.
Water Sci Technol ; 84(2): 314-322, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34312339

RESUMO

Operational data over 2 years from three large Austrian wastewater treatment plants (WWTPs) with design capacities of 4 million, 950,000 and 110,000 population equivalent (PE) were examined. Salt peaks, due to thawing road salt were detected and quantified by electrical conductivity, temperature and chloride measurement in the inflow of the WWTPs. Daily NaCl inflow loads up to 1,147 t/d and PE-specific loads of 0.26-0.5 kg NaCl/(PE · y) were found. To mimic the plants' behaviour in a controlled environment, NaCl was dosed into the inflow of a laboratory-scale activated sludge plant. The influence of salt peaks on important activated sludge parameters such as sludge volume index, settling velocity and floc size were investigated. Influent and effluent were sampled extensively to calculate removal rates. Respiration measurements were performed to quantify activated sludge activity. Particle size distributions of the activated sludge floc sizes were measured using laser diffraction particle sizing and showed a decrease of the floc size by approximately two-thirds. The floc structure was examined and documented using light microscopy. At salt concentrations below 1 g/L, increased respiration was found for autotrophic biomass, and between 1 and 3 g NaCl/L respiration was inhibited by up to 30%.


Assuntos
Esgotos , Purificação da Água , Áustria , Floculação , Cloreto de Sódio , Eliminação de Resíduos Líquidos , Águas Residuárias
3.
Water Sci Technol ; 80(9): 1654-1661, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32039897

RESUMO

In this research, sources of methane emissions of an anaerobic digester (AD) system at a municipal wastewater treatment plant (WWTP) with 260,000 population equivalent (PE) capacity were detected by a non-dispersive infrared (NDIR) camera. The located emissions were evaluated qualitatively and were documented with photographs and video films. Subsequently, the emission sources were quantified individually using different methods like the Flux-Chamber method and sampling from the digester's circulation pipe. The dissolved methane in the sludge digester was measured via gas chromatography-mass spectrometry (GC-MS) and 6.8% oversaturation compared to the equilibrium after Henry's law was found. Additionally, the residual gas potential of the digestate was measured using batch tests with 10 days' additional stabilisation time. The PE-specific residual gas production of the full-scale AD was calculated to 12.4 g CH4/(PE · y). An extended chemical oxygen demand (COD) balance including methane emissions for the whole digester system was calculated. Also the measured methane loads were calculated and summed up. The total methane loss of the AD was calculated at 24.6 g CH4/(PE · y), which corresponds to 0.4% of the produced biogas (4,913 g CH4/(PE · y)). PE-specific methane emission factors are presented for each investigated (point) source like the sludge outlet at the digester's head, a leaking manhole sealing and cracks in the concrete structure.


Assuntos
Metano , Eliminação de Resíduos Líquidos , Anaerobiose , Reatores Biológicos , Esgotos
4.
Water Sci Technol ; 57(7): 1087-94, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18441437

RESUMO

At a large Austrian municipal wastewater treatment plant enhanced stabilisation of anaerobically digested sewage sludge was required in order to get a permit for landfill disposal of the dewatered stabilized sludge. By implementing a post-aeration treatment after anaerobic digestion the organic content of the anaerobically well digested sludge can be decreased by 16%. Investigations at this plant showed that during digested sludge post-aeration anoxic phases are needed to provide stable process conditions. In this way the pH value can be kept in a more favourable range for micro-organisms and concrete structures. Additionally, under the process conditions applied nitrite accumulation would inhibit the stabilisation process if denitrification is not adequately applied. By optimising the aeration/pause ratio approximately 45% of total nitrogen in digested sludge can be removed. NH4-removal occurs through nitrification and denitrification with an efficiency of 98%. This significantly improves nitrogen removal efficiency at the wastewater treatment plant. The costs/benefit analysis shows that post-aeration of digested sludge results in an increase of total annual costs for wastewater treatment of only 0.84%, corresponding to 0.19 Euro/pe/a. Specific costs for nitrogen removal (0.32 Euro/kgN) are comparable with other biological processes for N-removal in reject water.


Assuntos
Nitrogênio/isolamento & purificação , Oxigênio/química , Esgotos/química , Anaerobiose , Análise Custo-Benefício
5.
Water Sci Technol ; 57(2): 257-64, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18235180

RESUMO

The paper will report about the experiences at an Austrian large wastewater treatment plant of 720,000 population equivalents, where anaerobically digested sewage sludge is further stabilised under aerobic conditions. Enhanced stabilisation of the anaerobically digested sludge was required at the plant in order to get a permit for landfill disposal of the dewatered stabilized sludge. By implementing a post-aeration treatment (SRT approximately 6d; 36 degrees C) after anaerobic digestion the organic content of the anaerobically well digested sludge can be decreased by 16%. Investigations on site showed that during digested sludge post-aeration anoxic phases for denitrification are needed to provide stable process conditions. In this way the pH value can be kept in a more favourable range for micro-organisms and concrete structures. Additionally, inhibition of the biological process due to nitrite accumulation can be avoided. By optimising the aeration/pause ratio approximately 45% of total nitrogen in digested sludge can be removed. This significantly improves nitrogen removal efficiency at the wastewater treatment plant. NH(4)-removal occurs mainly through nitritation and denitritation with an efficiency of 98%. The costs/benefit analysis shows that post-aeration of digested sludge results in an increase of total annual costs for wastewater treatment of only 0.84%, corresponding to 0.19 Euro/pe/a. Result of molecular biological analyses (DGGE) indicate that all four ammonium-oxidizing bacteria species present in activated sludge can survive anaerobic digestion, but only two of them can adapt in the digested sludge post-aeration tanks. Additionally, in the post-aerated digested sludge a further ammonium-oxidizing bacteria species was identified.


Assuntos
Nitrogênio/isolamento & purificação , Oxigênio/química , Esgotos/química , Esgotos/microbiologia , Anaerobiose , Nitrogênio/economia , Oxigênio/metabolismo
6.
Water Sci Technol ; 58(7): 1497-504, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18957765

RESUMO

Sugar beet press pulp (SBP) accumulates as a by-product in sugar factories and it is generally silaged or dried to be used as animal food. Rising energy prices and the opening of the European Union sugar market has put pressure on the manufacturers to find alternatives for energy supply. The aim of this project was to develop a technology in the treatment of SBP that would lead to savings in energy consumption and would provide a more competitive sugar production from sugar beets. These goals were met by the anaerobic digestion of SBP for biogas production. Lab-scale experiments confirmed the suitability of SBP as substrate for anaerobic bacteria. Pilot-scale experiments focused on process optimization and procedures for a quick start up and operational control. Both single-stage and two-stage process configurations showed similar removal efficiency. A stable biogas production could be achieved in single-stage at a maximum volumetric loading rate of 10 kgCSB/(m(3) x d). Degradation efficiency was 75% for VS and 72% for COD. Average specific gas production reached 530 NL/kgCOD(SBP) or 610 NL/kgVS(SBP). (CH(4): 50 to 53%). The first large-scale biogas plant was put into operation during the sugar processing period 2007 at a Hungarian sugar factory. Digesting approximately 50% of the SBP (800 t/d, 22%TS), the biogas produced could substitute about 40% of the natural gas required for the thermal energy supply within the sugar processing.


Assuntos
Beta vulgaris/metabolismo , Fontes de Energia Bioelétrica , Combustíveis Fósseis , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Bactérias Anaeróbias/metabolismo , Biodegradação Ambiental , Eliminação de Resíduos Líquidos/instrumentação
7.
Water Sci Technol ; 55(6): 181-9, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17486850

RESUMO

Long term lab-scale and bench-scale experiments were performed to investigate the feasibility of the anaerobic process to treat wastewater from a pulp and viscose fibre industry. Anaerobic wastewater treatment enables an advantageous combination of COD, sulphate and zinc removal from viscose wastewater. The aim of the investigations was to evaluate the influence of the free sulphide concentration on COD and sulphate removal efficiency and on the substrate competition between sulphate reducing and methanogenic bacteria. Since the wastewater did not contain enough COD for complete sulphate removal it was of major interest to determine favourable process conditions to steer the substrate competition in favour of sulphate reduction. Further experiments at bench-scale permitted us to evaluate applicable COD-loading rates and gain fundamental information about process stability and optimization for large-scale implementation. The present work will deal with the most relevant experimental results achieved and with important technological aspects of anaerobic treatment of viscose wastewater.


Assuntos
Bactérias Anaeróbias/fisiologia , Resíduos Industriais , Sulfatos/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo , Anaerobiose , Reatores Biológicos/microbiologia , Celulose , Estudos de Viabilidade , Methanomicrobiales/fisiologia , Oxirredução , Especificidade por Substrato , Sulfetos/química , Bactérias Redutoras de Enxofre/fisiologia , Purificação da Água/métodos , Zinco/isolamento & purificação
8.
Int J Parasitol ; 47(8): 447-455, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28322846

RESUMO

Geographical distribution of parasite species can provide insights into the evolution and diversity of parasitic communities. Biogeography of marine parasites is poorly known, especially because it requires an understanding of host-parasite interactions, information that is rare, especially over large spatial scales. Here, we have studied the biogeographical patterns of dactylogyrid parasites of chaetodontids, one of the most well-studied fish families, in the tropical Indo-west Pacific region. Dactylogyrid parasites were collected from gills of 34 butterflyfish species (n=560) at nine localities within an approximate area of 62millionkm2. Thirteen dactylogyrid species were identified, with richness ranging from 6 to 12 species at individual localities. Most dactylogyrid communities were dominated by Haliotrema angelopterum or Haliotrema aurigae, for which relative abundance was negatively correlated (ρ=-0.59). Parasite richness and diversity were highest in French Polynesia and the Great Barrier Reef (Australia) and lowest in Palau. Three biogeographic regions were identified based on dactylogyrid dissimilarities: French Polynesia, characterised by the dominance of H. angelopterum, the western Pacific region dominated by H. aurigae, and Ningaloo Reef (Australia), dominated by Euryhaliotrema berenguelae. Structure of host assemblages was the main factor explaining the dissimilarity (turnover and nestedness components of the Bray-Curtis dissimilarity and overall Bray-Curtis dissimilarity) of parasite communities between localities, while environment was only significant in the turnover of parasite communities and overall dissimilarity. Spatial structure of localities explained only 10% of the turnover of parasite communities. The interaction of the three factors (host assemblages, environment and spatial structure), however, explained the highest amounts of variance of the dactylogyrid communities, indicating a strong colinearity between the factors. Our findings show that spatial arrangement of chaetodontid dactylogyrids in the tropical Indo-west Pacific is primarily characterised by the turnover of the main Haliotrema spp., which is mainly explained by the structure of host assemblages.


Assuntos
Doenças dos Peixes/parasitologia , Peixes/parasitologia , Trematódeos/genética , Infecções por Trematódeos/veterinária , Animais , Australásia/epidemiologia , Doenças dos Peixes/epidemiologia , Oceano Pacífico/epidemiologia , Trematódeos/isolamento & purificação , Infecções por Trematódeos/epidemiologia , Infecções por Trematódeos/parasitologia
9.
Water Sci Technol ; 53(8): 81-90, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16784192

RESUMO

Further reduction of volatile suspended solids (VSS) during a post-stabilisation step was applied to evaluate the stabilisation degree of digested sewage sludge. For this purpose digested sludge was collected at four municipal wastewater treatment plants (WWTPs) and further stabilised in lab-scale chemostat reactors either under anaerobic or aerobic conditions. Experimental results showed that even in adequately digested sludge a consistent amount of VSS was degraded during aerobic post-stabilisation. It seems that aerobic conditions play a significant role during degradation of residual VSS. Additionally, specific VSS production (gVSS/peCOD110.d) as well as specific oxygen uptake rate were shown to be suitable parameters to assess the degree of sludge stabilisation at WWTPs. Fourier transform infrared spectroscopy was used to reveal changes in the sludge composition. Spectra of treated and untreated sludge samples indicated that the major component of residual VSS in stabilised sludge for instance consisted of biomass, while cellulose was absent.


Assuntos
Esgotos/microbiologia , Purificação da Água/métodos , Aerobiose , Anaerobiose , Biodegradação Ambiental , Biomassa , Reatores Biológicos , Esgotos/química , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Nat Commun ; 7: 10359, 2016 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-26756609

RESUMO

Although coral reefs support the largest concentrations of marine biodiversity worldwide, the extent to which the global system of marine-protected areas (MPAs) represents individual species and the breadth of evolutionary history across the Tree of Life has never been quantified. Here we show that only 5.7% of scleractinian coral species and 21.7% of labrid fish species reach the minimum protection target of 10% of their geographic ranges within MPAs. We also estimate that the current global MPA system secures only 1.7% of the Tree of Life for corals, and 17.6% for fishes. Regionally, the Atlantic and Eastern Pacific show the greatest deficit of protection for corals while for fishes this deficit is located primarily in the Western Indian Ocean and in the Central Pacific. Our results call for a global coordinated expansion of current conservation efforts to fully secure the Tree of Life on coral reefs.


Assuntos
Antozoários/genética , Evolução Biológica , Conservação dos Recursos Naturais , Peixes/genética , Animais , Clima Tropical
11.
Nat Commun ; 7: 10491, 2016 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-26839155

RESUMO

Coral reefs are among the most species-rich and threatened ecosystems on Earth, yet the extent to which human stressors determine species occurrences, compared with biogeography or environmental conditions, remains largely unknown. With ever-increasing human-mediated disturbances on these ecosystems, an important question is not only how many species can inhabit local communities, but also which biological traits determine species that can persist (or not) above particular disturbance thresholds. Here we show that human pressure and seasonal climate variability are disproportionately and negatively associated with the occurrence of large-bodied and geographically small-ranging fishes within local coral reef communities. These species are 67% less likely to occur where human impact and temperature seasonality exceed critical thresholds, such as in the marine biodiversity hotspot: the Coral Triangle. Our results identify the most sensitive species and critical thresholds of human and climatic stressors, providing opportunity for targeted conservation intervention to prevent local extinctions.


Assuntos
Biodiversidade , Clima , Conservação dos Recursos Naturais , Recifes de Corais , Ecossistema , Peixes , Estações do Ano , Animais , Tamanho Corporal , Humanos , Estresse Fisiológico , Temperatura
12.
J Leukoc Biol ; 69(5): 831-40, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11358993

RESUMO

We investigated possible expression and function in mast cells of protein kinase C (PKC) theta, a member of the PKC family with demonstrated function in a limited range of cell types. We found that PKC theta is expressed in bone marrow-derived mast cells and in the RBL-2H3 mast cell line. PKC theta underwent translocation to the membrane in response to Fcepsilon receptor I (FcepsilonR I) activation. Receptor activation induced phosphorylation of PKC theta. The tyrosine phosphorylation of PKC theta is delayed relative to PKC delta and coincides temporally with PKC theta association with c-src family members Lyn and SRC: Studies of RBL-2H3 cells transduced with PKC theta constructs indicated a role for PKC theta in receptor-induced activation of extracellular regulated kinases, interleukin-3 gene transcription, and degranulation in response to antigen stimulation. These studies extend the known functions of PKCtheta to another important immune cell type and indicate the concurrent participation of multiple PKCs in the FcepsilonR I-mediated response of mast cells.


Assuntos
Isoenzimas/imunologia , Mastócitos/imunologia , Proteína Quinase C/imunologia , Receptores de IgE/imunologia , Transdução de Sinais/imunologia , Animais , Antígenos/imunologia , Antígenos/farmacologia , Degranulação Celular , Linhagem Celular , Células Cultivadas , Reagentes de Ligações Cruzadas , Dinitrofenóis/imunologia , Dinitrofenóis/farmacologia , Ativação Enzimática , Expressão Gênica , Humanos , Interleucina-3/genética , Isoenzimas/genética , Isoenzimas/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Mastócitos/citologia , Mastócitos/efeitos dos fármacos , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosforilação , Proteína Quinase C/genética , Proteína Quinase C/metabolismo , Proteína Quinase C-theta , RNA Mensageiro , Albumina Sérica/imunologia , Albumina Sérica/farmacologia , Quinases da Família src/metabolismo
13.
Bioresour Technol ; 100(5): 1775-80, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19010667

RESUMO

Sewage sludge samples representing different stages during waste water and sewage sludge treatment were collected at four Austrian municipal waste water treatment plants. Changes of sludge composition are reflected by a specific infrared spectroscopic pattern. Anaerobically digested sludge was subjected to aeration in lab-scale reactors in order to find out if post-aeration after anaerobic digestion provides enhanced organic matter degradation and stabilization. Spectral data were evaluated by means of multivariate statistics. Similar spectral characteristics of sludge degradation stages were visualized by principal component analysis. The effect of additional aerobic treatment of anaerobically stabilized sludge was revealed by discriminant analysis that distinguishes additionally aerated sludge from all the other degradation stages of sludge because of changes in the spectral pattern by increasing stabilization. Based on partial least squares regression (PLSR) a correlation coefficient of R(2)=0.91 was found between spectral characteristics and the chemical oxygen demand (COD).


Assuntos
Bactérias Aeróbias/metabolismo , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Análise Discriminante , Análise Multivariada , Oxigênio/metabolismo , Análise de Componente Principal , Análise de Regressão , Espectrofotometria Infravermelho
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA