Electrodialytic treatment of sewage sludge: influence on microbiological community     

Paula Guedes  Nazaré Couto  Joana Almeida  António M. Rodrigues  Eduardo P. Mateus  Alexandra B. Ribeiro 《International Journal of Environmental Science and Technology》2018,15(5):1103-1112

This study aimed to evaluate the changes in microbiological communities present in sewage sludge (SS) when subjected to an electric field. The establishment of these relations is important to design and optimize an electrotechnology that not only promotes a direct degradation of the emerging organic contaminants, through electrodegradation, but also stimulates their biodegradation. Different current intensities were used continuously or by steps, in a two compartment electrodialytic (ED) cell. Samples collected between May and July of 2015 were analysed, prior to ED treatment, and the 35 Taxa identified were divided in 12 groups. Initial samples, collected on May, were mainly constituted by stalked ciliates (86%), followed by shelled amoebae (8%), whereas the samples collected between June and July presented higher number of shelled amoebae, between 52 and 92%. Epistylis, Vorticella and Arcella gibbosa were the most frequent protozoa identified. Samples richness (R) was between 7 and 14, Simpson’s biodiversity index (D) between 0.45 and 0.69, and evenness between 0.42 and 0.65. At the end of the ED experiments, a decrease in the number of identified Taxa and individuals was observed and, consequently, SS biodiversity also decreased. This decline was more pronounced in the ED experiments conducted with currents above 50 mA (0.10 mA cm^?2). In terms of abundance, the final SS was mainly constituted by shelled amoebae that showed to be the most resistant to the conditions within the ED cell. The obtained results showed that the studied conditions within the ED cell were not appropriate to the microbiological communities, which influenced the final SS quality.  相似文献   

Tracing salinization processes in coastal aquifers using an isotopic and geochemical approach: comparative studies in western Morocco and southwest Portugal     

Paula M. Carreira  Mohamed Bahir  Ouhamdouch Salah  Paula Galego Fernandes  Dina Nunes 《Hydrogeology Journal》2018,26(8):2595-2615

Environmental stable and radioactive isotopes (δ²H, δ¹³C, δ¹⁸O; ³H and ¹⁴C), together with physical and geochemical data, were used in the determination of the origins of groundwater salinization and geochemical evolution processes in coastal regions. Two case studies on the Atlantic Coast are discussed, one located in the Essaouira sedimentary basin, western Morocco, and the second, in the Lower Tagus–Sado sedimentary basin, southwest Portugal. In both regions, groundwater degradation occurs by salinization increase to different concentrations and in relation to different origins. The main quality issues for the groundwater resources are related to seawater intrusion, dissolution of diapiric structures intruding the aquifer layers, brine dissolution at depth, and/or evaporation of irrigation water. Anthropogenic pollution ascribed to agricultural activities is another source for groundwater degradation, affecting mainly the shallow aquifers. The apparent ¹⁴C age of the analysed samples ranges from 2.9?±?0.3 up to 45.6?±?0.6 pmC in the Miocene groundwater samples from the basin in Portugal; at the Essaouira basin in Morocco, the ¹⁴C content varies from 60 to 86 pmC. In most of the water samples, the ³H concentration is below the detection limit. In both basins, the isotopic results together with the geochemical data provided an effective label for tracing the mineralization origin and groundwater degradation processes. Further, the isotopic signatures were used in the identification of a paleoclimate (colder period), recorded in the stable isotopic composition and corroborated with the ¹⁴C data.  相似文献   

Evaluation of daily precipitation statistics and monsoon onset/retreat over western Sahel in multiple data sets     

Diaconescu  Emilia Paula  Gachon  Philippe  Scinocca  John  Laprise  René 《Climate Dynamics》2015,45(5-6):1325-1354

Climate Dynamics - The West Africa rainfall regime constitutes a considerable challenge for Regional Climate Models (RCMs) due to the complexity of dynamical and physical processes that...  相似文献   

Partitioning of the feeding niche along spatial,seasonal and size dimensions by the fish community in a tropical Bay in Southeastern Brazil          下载免费PDF全文

Ana Paula P. Guedes  Francisco G. Araújo  André L. M. Pessanha  Rosana R. Milagre 《Marine Ecology》2015,36(1):38-56

Feeding guilds and spatial, seasonal and ontogenetic changes in the diets of 24 fish species in a tropical bay in Southeastern Brazil were examined. The hypotheses tested were that groups of species form specific trophic guilds and that the feeding partitioning differs along the niche dimensions. Five trophic guilds (Polychaeta, Copepoda, Teleostei, Teleostei/Crustacea and Polychaeta/Crustacea) and two species with specialised feeding, one teleost (Aspistor luniscutis) and one bivalvia (Sphoeroides testudineus), were found. Polychaeta was the most important resource for nine fish species, followed by Copepoda (6 spp.), Teleostei (5 spp.) and Caprelidae Amphipoda (3 spp.). Polychaeta was the most used resource for species in the inner bay zone, and Crustaceans in the outer bay zone. We detected a predominance of Polychaeta between the spring and autumn, whereas crustaceans were consumed at a greater rate in the winter. The most conspicuous changes in diet occurred along the spatial and seasonal dimensions, rather than the size dimensions. The hypotheses tested were accepted. Identifying and incorporating information about the bay food web is a first step towards developing management strategies that are sensitive to this particular ecosystem.  相似文献   

Chironomid‐inferred late‐glacial summer air temperatures from Lough Nadourcan,Co. Donegal,Ireland     

Jenny E. Watson  Stephen J. Brooks  Nicki J. Whitehouse  Paula J. Reimer  H. John B. Birks  Chris Turney 《第四纪科学杂志》2010,25(8):1200-1210

Western Ireland, located adjacent to the North Atlantic, and with a strongly oceanic climate, is potentially sensitive to rapid and extreme climate change. We present the first high‐resolution chironomid‐inferred mean July temperature reconstruction for Ireland, spanning the late‐glacial and early Holocene (LGIT, 15–10 ka BP). The reconstruction suggests an initial rapid warming followed by a short cool phase early in the interstadial. During the interstadial there are oscillations in the inferred temperatures which may relate to Greenland Interstadial events GI‐1a–e. The temperature decrease into the stadial occurs in two stages. This two‐stage drop can also be seen in other late‐glacial chironomid‐inferred temperature records from the British Isles. A stepped rise in temperatures into the Holocene, consistent with present‐day temperatures in Donegal, is inferred. The results show strong similarities with previously published LGIT chironomid‐inferred temperature reconstructions, and with the NGRIP oxygen‐isotope curve, which indicates that the oscillations observed in the NGRIP record are of hemispherical significance. The results also highlight the influence of the North Atlantic on the Irish climate throughout the LGIT. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Hard X-ray emission from the SNR G337.2+0.1     

Jorge A. Combi  Juan F. Albacete Colombo  Gustavo E. Romero  Paula Benaglia 《Astrophysics and Space Science》2007,309(1-4):395-399

We report hard X-ray emission of the non-thermal supernova remnant G337.2+0.1. The source presents centrally filled and diffuse X-ray emission. A spectral study confirms that the column density of the central part of the object is about N _H∼5.9(±1.5)×10²² cm⁻² and its X-ray spectrum is well represented by a single power-law with a photon index Γ=0.96±0.56. Detailed spectral analysis indicates that the outer region is highly absorbed and quite softer than the inner region. Characteristics already observed in other well-known X-ray plerions. Based on the gathered information, we confirm the SNR nature of G337.2+0.1, and suggest that the central region of the source is a pulsar wind nebula (PWN), originated by an energetic though yet undetected pulsar.  相似文献   

Paleoenvironmental reconstruction of a Late Quaternary lagoon system in southern Brazil (Jaguaruna region,Santa Catarina state) based on multi‐proxy analysis     

Paula Garcia Carvalho do Amaral  Paulo César Fonseca Giannini  Florence Sylvestre  Luiz Carlos Ruiz Pessenda 《第四纪科学杂志》2012,27(2):181-191

This paper provides a paleoenvironmental reconstruction of a Late Quaternary lagoon system in the Jaguaruna region of Santa Catarina state, southern Brazil. Integrated results of bulk sedimentary organic matter characterization (δ¹³C, δ¹⁵N and C/N), microfossil (pollen and diatom) and grain‐size analysis from three shallow cores (～2.5 m depth) allowed us to propose an evolving paleogeographic scenario in this coastal region for the last ca. 5500 cal a BP. The lagoonal system in this area was more extensive during the mid‐Holocene than today, with a gradual and continuous lagoon–sea disconnection until the present. We add to the debate regarding relative sea‐level (RSL) variations for the Brazilian coast during the Holocene and discuss the importance of sedimentary dynamics for interpreting changes in coastal ecosystems. The multi‐proxy analysis suggests that changes in coastal ecosystems could be directly related to local sedimentary processes, which are not necessarily linked to RSL fluctuations and/or to climatic variations. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

A late Pleistocene–Holocene multi‐proxy record of palaeoenvironmental change from Still Bay,southern Cape Coast,South Africa          下载免费PDF全文

Lynne J. Quick  Andrew S. Carr  Michael E. Meadows  Arnoud Boom  Mark D. Bateman  David L. Roberts  Paula J. Reimer  Brian M. Chase 《第四纪科学杂志》2015,30(8):870-885

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The role of true polar wander on the Jurassic palaeoclimate     

María Paula Iglesia Llanos  Claudia Beatriz Prezzi 《International Journal of Earth Sciences》2013,102(3):745-759

From the Late Carboniferous until the Middle Jurassic, continents were assembled in a quasi-rigid supercontinent called Pangea. The first palaeomagnetic data of South America indicated that the continent remained stationary in similar present-day latitudes during most of the Mesozoic and even the Palaeozoic. However, new palaeomagnetic data suggest that such a scenario is not likely, at least for the Jurassic. In order to test the stationary versus the dynamic-continent model, we studied the Jurassic apparent polar wander paths of the major continents, that is, Eurasia, Africa and North America that all in all show the same shape and chronology of the tracks with respect to those from South America. We thus present a master path that could be useful for the Jurassic Pangea. One of the most remarkable features observed in the path is the change in pole positions at ~197 Ma (Early Jurassic), which denotes the cessation of the counter-clockwise rotation of Pangea and commencement of a clockwise rotation that brought about changes in palaeolatitude and orientation until the end of the Early Jurassic (185 Ma). Here, we analyse a number of phenomena that could have triggered the polar shift between 197 and 185 Ma and conclude that true polar wander is the most likely. In order to do this, we used Morgan’s (Tectonophysics 94:123–139, 1983) grid of hotspots and performed “absolute” palaeogeographical reconstructions of Pangea for the Late Triassic and Jurassic. The palaeolatitudes changes that we observe from our palaeomagnetic data are very well sustained by diverse palaeoclimatic proxies derived from geological and palaeoecological data at this time of both the southern and northern hemispheres.  相似文献   

The 1909 Benavente (Portugal) earthquake: search for the source   总被引：1，自引：0，他引：1  

J. Cabral  C. Moniz  J. Batlló  P. Figueiredo  J. Carvalho  L. Matias  P. Teves-Costa  R. Dias  N. Simão 《Natural Hazards》2013,69(2):1211-1227

The Lower Tagus River Valley has been affected by severe earthquakes comprising distant events, as in 1755, and local earthquakes, as in 1344, 1531, and 1909. The 1909 earthquake was located NE of Lisbon, near Benavente, causing serious damage and many losses. Mw 6.0 has been assessed for this earthquake and a reverse faulting focal mechanism solution has been calculated. Poor epicenter location, possible directivity and site effects, low fault slip rates, and the thick Cenozoic sedimentary cover make difficult correlation with regional structures. The focal mechanism indicates an ENE reverse fault as source, though it does not match any outcropping active structure suggesting that the event could have been produced by a blind thrust beneath the Cenozoic sedimentary fill. Hidden sources, inferred from seismic reflection data, are a possible NE structure linking the Vila Franca de Xira and the Azambuja faults, or the southern extension of the later. Evidence of surface rupturing is inhibited by the thick Holocene alluvial cover and the high fluvial sedimentation rate, though a slightly depressed area was identified in the Tagus alluvial plain W of Benavente which was investigated as possible geomorphic evidence of co-seismic surface deformation. A high-resolution seismic reflection profile was acquired across a 0.5 m high scarp at this site, and two trenches were opened across the scarp for paleoseismic research. Some deformation of dubious tectonic origin was found, requiring further studies.  相似文献