Nursery Habitat Shifts in an Estuarine Ecosystem<Emphasis Type="Bold">:</Emphasis> Patterns of Use by Sympatric Catfish Species     

David Valença Dantas  Mario Barletta  André Ricardo Araújo Lima  Jonas de Assis Almeida Ramos  Monica Ferreira da Costa  Ulrich Saint-Paul 《Estuaries and Coasts》2012,35(2):587-602

The seasonal and spatial distribution (density and biomass) of five size classes of two catfish species (Cathorops spixii and Cathorops agassizii) were studied along an estuarine ecocline to test the relative importance of the nursery function of each habitat. Seasonal vs. area interactions were significant for all size classes of both species. During the early rainy season, the middle estuary is an important nursery habitat for juveniles of both species. When environmental conditions change during the late rainy season, the C. spixii primary nursery habitat shifts to the lower estuary. During this period, juveniles of C. agassizii remain in the middle estuary. Another important ecological area is the upper estuary, which becomes a breeding, spawning and hatchery area during the late dry season for both species. The nursery function of habitats shifts according to the seasonal fluctuation of salinity and dissolved oxygen, and each species responds differently to this change.  相似文献   

Geochemical study of submicron particulate matter(PM1)in a metropolitan area     

Ismael L.Schneider  Elba C.Teixeira  Guilherme L.Dotto  Diana Pinto  Cheng-Xue Yang  Luis F.O.Silva 《地学前缘(英文版)》2022,(1):417-429

Air pollution has become a major problem in urban areas due to increasing industrialization and urbanization.In this study ambient concentrations of PM1 and metal concentrations as well as source contributions were identified and quantified by using Positive Matrix Factorization(PMF)in receptor modeling in the Metropolitan Area of Porto Alegre,Brazil.The PM1 samples were collected on PTFE filters from December 2012 to December 2014 in two sampling sites.Major ion and trace element concentrations were assessed.The average concentrations were 12.8 and 15.2μg/m³ for Canoas and Sapucaia do Sul sites,respectively.Major ion contributions of PM1 were secondary pollutants such as sulfate and nitrate.Trace elements,especially Cu,Pb,Zn,Cd,and Ni also made important contributions which are directly associated with anthropogenic contributions.Our results show significantly higher levels in winter than in summer.Most of the PM1 and the analyzed PM species and elements originated from anthropogenic sources,especially road traffic,combustion processes and industrial activities,which are grouped in 7 major contributing sources.A back-trajectory analysis showed that the long-range transport of pollutants was not relevant in relation to the contribution to PM1 and metal concentrations.This work highlights the importance of urban planning to reduce human health exposure to traffic and industrial emissions,combined with awareness-raising actions for citizens concerning the impact of indoor sources.  相似文献   

Defluoridation of Groundwater Using Raw Bauxite: Kinetics and Thermodynamics          下载免费PDF全文

Chikumbusho Kayira  Samson Sajidu  Wellington Masamba  Jonas Mwatseteza 《洁净——土壤、空气、水》2014,42(5):546-551

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Operating Parameters Affecting the Formation of Kaolin Aerated Flocs in Water and Wastewater Treatment          下载免费PDF全文

Cristiane Oliveira  Rafael Teixeira Rodrigues  Jorge Rubio 《洁净——土壤、空气、水》2014,42(7):909-916

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Spatial distribution of metals in sediments of the Ribeira Bay, Angra dos Reis, Rio de Janeiro, Brazil   总被引：1，自引：0，他引：1  

N.V. Freret-Meurer  J.V. Andreata  B.C. Meurer  F.V. Manzano  M.G.S. Baptista  D.E. Teixeira  M.M. Longo 《Marine pollution bulletin》2010,60(4):627-629

This study aims to analyze the spatial distributions of several metals in sediments from five sites in Ribeira Bay, Brazil. Ribeira Bay is a very important area to the local community, due to its artisan fishery, and it also has a biological relevance for many marine species that use mangroves as nursery and feeding sites. According to the results, the area was not considered a metal polluted area. Despite not having a significant source of metals inside the Bay nowadays, Ilha Grande Bay harbors a shipyard, an oil terminal, and a commercial port, as well as two thermonuclear power plants (Angra I e II), all of which indirectly influence the study area.  相似文献   

A multi‐method field experiment to determine local groundwater flow in a glacier forefield          下载免费PDF全文

Florian Kobierska  Tobias Jonas  Nena Griessinger  Christian Hauck  Stephan Huxol  Stefano M. Bernasconi 《水文研究》2015,29(6):817-827

We implemented multiple independent field techniques to determine the direction and velocity of groundwater flow at a specific stream reach in a glacier forefield. Time‐lapse experiments were conducted using two electrical resistivity tomography (ERT) lines installed in a cross pattern. A circular array of groundwater tubes was also installed to monitor groundwater flow via discrete salt injections. Both inter‐borehole and ERT results confirmed this stream section as a losing reach and enabled quantification of the flow direction. Both techniques yielded advection velocities varying between 5.7 and 21.8 m/day. Estimates of groundwater flow direction and velocity indicated that groundwater infiltrates from the stream nearby and not from the adjacent lateral moraine. Groundwater age estimated from radon concentration measurements supported this hypothesis. Despite uncertainties inherent to each of the methods deployed, the combination of multiple field techniques allowed drawing consistent conclusions about local groundwater flow. We thus regard our multi‐method approach as a reliable way to characterize the two‐dimensional groundwater flow at sites where more invasive groundwater investigation techniques are difficult to carry out and local heterogeneities can make single measurements unreliable. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Gravity data as a tool for landfill study     

João B. C. Silva  Wlamir A. Teixeira  Valéria C. F. Barbosa 《Environmental Geology》2009,57(4):749-757

This paper shows the potential of gravity data to map a buried landfill bottom topography. To this end, a gravity inversion method is presented for estimating the landfill’s bottom depths at discrete points assuming a decrease of the density contrast with depth according to a hyperbolic law. The method’s efficiency was tested using synthetic data from simulated waste landfills, producing estimated bottom topographies very close to the true ones. The method’s potentiality has been further evaluated in applying it to the gravity data from the abandoned Thomas Farm Landfill site, Indiana, USA, whose bottom topography is known. The estimated topography showed close agreement with the known Thomas Farm Landfill’s bottom topography.  相似文献   

Spitzer imaging of the jet driving the NGC 2264 G outflow     

P. S. Teixeira  C. McCoey  M. Fich  C. J. Lada 《Monthly notices of the Royal Astronomical Society》2008,384(1):71-76

We present new infrared imaging of the NGC 2264 G protostellar outflow region, obtained with the InfraRed Array Camera (IRAC) onboard the Spitzer Space Telescope . A jet in the red outflow lobe (eastern lobe) is clearly detected in all four IRAC bands and, for the first time, is shown to continuously extend over the entire length of the red outflow lobe traced by CO observations. The redshifted jet also extends to a deeply embedded Class 0 source, Very Large Array (VLA) 2, confirming previous suggestions that it is the driving source of the outflow ( Gómez et al. 1994 ). The images show that the easternmost part of the redshifted jet exhibits what appear to be multiple changes of direction. To understand the redshifted jet morphology, we explore several mechanisms that could generate such apparent changes of direction. From this analysis, we conclude that the redshifted jet structure and morphology visible in the IRAC images can be largely, although not entirely, explained by a slowly precessing jet (period ≈8000 yr) that lies mostly on the plane of the sky. It appears that the observed changes in the redshifted jet direction may be sufficient to account for a significant fraction of the broadening of the outflow lobe observed in the CO emission.  相似文献   

Application of laser anemometry for measuring critical bed shear stress of sediment core samples     

M.A.V.C. Araújo  J.C.F. Teixeira  S.F.C.F. Teixeira 《Continental Shelf Research》2008

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Submarine landslides caused by seamounts entering accretionary wedge systems          下载免费PDF全文

Jonas B. Ruh 《地学学报》2016,28(3):163-170

Seamounts entering active subduction zone trenches initially collide with the frontal sedimentary accretionary wedges resulting in severe deformation of the overriding plate. A typical feature of this deformation is the occurrence of submarine landslides due to gravitational instabilities. Such landslides have been reported from the Middle America and Hikurangi trenches and potentially generate tsunami waves. Yet, the dynamics of accretionary wedges during seamount indentation, and landsliding as a mechanical response in particular, have not been investigated qualitatively. Here, I use 3D high‐resolution numerical experiments to model the collision of conical and flat‐topped seamounts into accreting sedimentary sequences. Results show that the topographical evolution of an accretionary wedge mainly depends on the volume of the entering seamount and not on its height. Submarine landslides occur only if seamounts are not completely buried by the sedimentary sequence, and the volume of the avalanche is roughly correlated with the seamount volume overtopping the incoming sediments.  相似文献