DNA strand breaks in grass shrimp embryos exposed to highway runoff sediments and sediments with coal fly ash     

Lee RF  Niencheski LF  Brinkley K 《Marine environmental research》2008,66(1):164-165

Embryo production was reduced in female grass shrimp exposed to sediments with added coal fly ash and to sediments collected from an estuarine station containing high PAH concentrations due to its proximity to a highway storm drain. Grass shrimp embryos exposed to pore water from the high PAH and high metal sediments showed both reduced hatching and increases in DNA strand breaks (comet assay). Sediments with added coal fly ash had high concentrations of vanadium and selenium which may have contributed to effects similar to those observed with sediments with high PAH. The embryo pore water bioassay (hatching/DNA strand breaks) gave results comparable to those observed for reproduction effects (reduced embryo production/embryo hatching) with female grass shrimp exposed to whole sediment.  相似文献   

Community structure and functional traits of mollusks associated with coastal reef macroalgae in Northeastern Brazil     

Dbora Ferreira Barbosa  Thelma Lúcia Pereira Dias  Srgio de Faria Lopes  Rafaela Cristina de Souza Duarte  Fernanda Maria Duarte do Amaral 《Marine Ecology》2019,40(5)

This study investigated the community structure and functional traits of the mollusk fauna associated with macroalgae with different thallus morphologies in a reef environment in Northeastern Brazil. A total of 15 individuals of each species of macroalgae adhered to natural substrate and 15 individuals of Padina gymnospora detached from the substrate were collected. The structural complexity of algal habitats was measured and the associated malacofauna screened and identified. All three macroalgae differed significantly in the complexity of their habitat, with Sargassum polyceratium being the most complex. A total of 823 specimens of mollusks belonging to 22 species and 11 families were recorded, of which Columbellidae was the most represented with six species. The functional trait “size” revealed that micromollusks smaller than 10 millimeters were predominant in the community; however, individuals of larger sizes (up to 24.54 millimeters) belonging to young stages of other species were also present. Eight functional trophic groups were identified, of which “carnivorous” stood out with seven species. Six functional groups of microhabitats were identified, with intra‐specific variation in habitats, while habitat expansion was documented for species not yet recorded in association with macroalgae. The structure of the molluskan community differed among the three algae species with the greatest richness, abundance, and diversity of mollusks and functional traits occurring with S. polyceratium. Community structure differed between algae adhered to natural substrate and detached algae, with the latter having lower mollusk richness and diversity, but with greater abundance of some species that remained on algal fronds after release from the reef environment. This study reinforces the importance of algal habitat for marine invertebrate fauna, especially for micromollusks that spend their entire life cycle, or part of it, in association with macroalgae.  相似文献   

Extracts of the seaweed Bifurcaria bifurcata display antifungal activity against human dermatophyte fungi     

Carvalho  G. Loïc  Silva  Raquel  Gonçalves  J. Maria  Batista  T. Maria  Pereira  Leonel 《中国海洋湖沼学报》2019,37(3):848-854

Bifurcaria bifurcata is a seaweed of the Order Fucales(Ochrophyta, Phaeophyceae) that can be found all year round along the Portuguese Atlantic shore. Although it is considered edible in some countries,its biotechnological potential has not yet been assessed in detail and here we report its antimicrobial potential against human dermatophyte fungi. Three samples were harvested from Baleal Island(Peniche, Portugal)harvested in winter(BbPe); from Aguda Beach(Arcozelo, Vila Nova de Gaia, Portugal), harvested in autumn(BbAg) and a sample obtained by culturing the Aguda sample under laboratory conditions(BbLC).A broth macrodilution assay was applied to determine the MIC(minimum inhibitory concentration) and MLC(minimum lethal concentration) of the B. bifurcata extracts. Results show that the BbPe MeOH extracts were the most effective and had higher antifungal activity against all the tested dermatophyte strains than the BbLC and BaAg extracts [Epidermophyton floccosum FF9(100-200 μg/mL MIC; 200 μg/mL MLC), Microsporum canis FF1(400 μg/mL MIC; 400 μg/mL MLC), Trichophyton mentagrophytes FF7(100 μg/mL MIC; 800 μg/mL MLC), M. gypseum CECT 2908(800 μg/mL MIC; 800 μg/mL MLC), T.mentagrophytes var. interdigitale CECT 2958(800 μg/mL MIC; 800 μg/mL MLC), T. rubrum CECT 2794(200 μg/mL MIC; 400 μg/mL MLC)]. In fact, only E. floccosum FF9 was sensitive to BbAg and BbLC MeOH extracts. To our knowledge, this is the first report of antifungal activity of B. bifurcata against human dermatophyte fungi.  相似文献   

Hydrodynamic simulation of a floating wave energy converter by a U-tube rig for power take-off testing     

A.F. de O. Falcão  P.E.R. Pereira  J.C.C. Henriques  L.M.C. Gato 《Ocean Engineering》2010,37(14-15):1253-1260

Floating oscillating-bodies constitute an important class of offshore wave energy converters. The testing of their power take-off equipment (PTO) (high-pressure hydraulics, linear electrical generator or other) under realistically simulated sea conditions is usually regarded as a major task. A laboratory rig, consisting of a U-tube enclosing an oscillating column of water driven by a time-varying air-pressure, was devised to simulate the hydrodynamics of an oscillating buoy absorbing energy from sea waves, especially the inertia and the resonant frequency of the oscillating body. The PTO force is applied (by means of a piston) on one of the ends of the U-tube oscillating water column, whereas the other end is subject to a controlled time-varying air pressure. This is found to provide a reasonably realistic way of testing the PTO system (including its control) at an adequate scale (say about 1:5 to 1:4), which would avoid the use of a much more expensive experimental facility (very large wave tank) or testing in real wind-generated sea-waves. The matching conditions that the U-tube geometry and the driving time-varying air pressure must meet to ensure an adequate simulation are derived. These conditions leave some freedom to the U-tube rig designer and operator, allowing practical and engineering issues to be taken into account.  相似文献   

Humic substances in estuarine soils colonized by Spartina maritima     

Cristina Santín  Martha Gonzlez-Prez  Xos Luis Otero  Miguel ngel lvarez  Felipe Macías 《Estuarine, Coastal and Shelf Science》2009,81(4):481-490

This study characterizes humic substances (HS) from two soils colonized by Spartina maritima at different physiographical positions in estuarine environments on the north-western coast of the Iberian Peninsula: the Villaviciosa site, a stand close to the main tidal channel, and the Ortigueira site, located in the low salt marsh. Humic and fulvic acids were extracted from the soils and characterized qualitatively by the following spectroscopic techniques: Fourier transform infrared spectroscopy, fluorescence spectroscopy and solid-state ¹³C nuclear magnetic resonance.The characterized HS showed a predominance of low humified compounds with a high proportion of aliphatic components and a low degree of aromaticity. The HS composition differed substantially between sites. In the Villaviciosa soil, the large amount of nonpolar aliphatic components and the very low degree of aromaticity may indicate a significant contribution of marine organic matter and/or microbial material to the HS. However, in the HS from the Ortigueira soil, the higher proportion of polysaccharides together with the presence of lignin-derived compounds may indicate greater inputs of vascular plant material. The δ¹³C isotopic composition of the bulk soils highlights the large input of Spartina maritima debris to the Ortigueira site, whereas in the Villaviciosa site, organic contributions from this C4 vascular plant were not so evident.The results indicate that in these soils colonized by Spartina maritima, physiographical position has an important effect on the composition of soil HS and, therefore, must be considered in the study of organic matter characteristics in such estuarine environments.  相似文献   

Variation in the mobilization of mercury into Black-winged Stilt Himantopus himantopus chicks in coastal saltpans,as revealed by stable isotopes     

P.C. Tavares  A. Kelly  R. Maia  R.J. Lopes  R. Serrão Santos  M.E. Pereira  A.C. Duarte  R.W. Furness 《Estuarine, Coastal and Shelf Science》2008

Causes of variation in mobilization of mercury into Black-winged Stilt Himantopus himantopus chicks were studied through analysis of stable isotope ratios of carbon and nitrogen. Blood and breast feathers were collected from chicks in coastal saltpans during successive breeding seasons. Detritus samples and potential prey (macroinvertebrates) were also collected. Total mercury concentrations and stable isotope signatures were measured using atomic absorption spectroscopy and isotope ratio mass spectrometry respectively. Mercury levels in Chironomidae, Corixidae and Hydrophilidae correlated with mercury levels in chick feathers. Differences of δ¹⁵N signatures between macroinvertebrate groups indicated that they belong to different trophic levels. δ¹⁵N signatures of invertebrates correlated with mercury levels in invertebrates and chicks, but not with δ¹⁵N signatures in chicks. Between-group and between-site differences of δ¹⁵N signatures and mercury levels in invertebrates suggested that they contribute differently to mercury mobilization into chicks, and their relative contribution depends on prey availability in each site. Inter-site differences in the biomagnification factor reinforced that idea. δ¹³C signatures in invertebrates marked a larger range of carbon sources than just detritus. Variation of water inflow regime and prey availability may cause between-group and between-site differences of δ¹³C signatures in prey. Discrepancies between feather and blood for δ¹³C signatures in Praias-Sado and Vaia suggested that temporal variation of prey availability may be the main factor affecting mercury mobilization into chicks in both those cases, since their water inflow regimes are the same. The lowest levels of δ¹³C signatures in Vau suggested that water inflow regime may be the main factor in this case, since no discrepancy existed in δ¹³C signatures between blood and feather.  相似文献   

Assessing multidecadal runoff (1970–2010) using regional hydrological modelling under data and water scarcity conditions in Peruvian Pacific catchments     

Pedro Rau  Luc Bourrel  David Labat  Denis Ruelland  Frdric Frappart  Waldo Lavado  Boris Dewitte  Oscar Felipe 《水文研究》2019,33(1):20-35

In a context of water scarcity in Peruvian Pacific catchments as a crucial issue for Peru, added to the paucity of data availability, we propose a methodology that provides new perspectives for freshwater availability estimation as a base reference for unimpaired conditions. Under those considerations, a regional discharge of 709 m³/s to the Pacific Ocean is estimated with a significant increasing trend of about 43 m³/s per decade over the 1970 – 2010 period. To represent the multidecadal behaviour of freshwater runoff along the region, a regional runoff analysis is proposed based on hydrological modelling at annual and monthly time step for unimpaired conditions over the whole 1970 – 2010 period. Differential Split‐Sample Tests are used to assess the hydrological modelling robustness of the GR1A and GR2M conceptual lumped models, showing a satisfactory transposability from dry to wet years inside the thresholds defined for Nash–Sutcliffe and bias criteria. This allowed relating physical catchment characteristics with calibrated and validated model parameters, thus offering a regional perspective for dryland conditions in the study area (e.g., the anticlockwise hysteresis relationship found for seasonal precipitation–runoff relationship) as well as the impacts of climate variability and catchment characteristics.  相似文献   

Molecular composition and chemosystematic aspects of Cretaceous amber from the Amazonas,Araripe and Recôncavo basins,Brazil     

Ricardo Pereira  Ismar de Souza Carvalho  Bernd R.T. Simoneit  Débora de Almeida Azevedo 《Organic Geochemistry》2009,40(8):863-875

Amber occurrences in Brazil are rare. In this regard, the molecular composition of three such fossil resin samples from Brazilian Cretaceous sedimentary basins has been analyzed to determine the botanical origin of the resins. The samples were collected from the Amazonas (Alter do Chão Formation), Araripe (Santana Formation, Crato Member) and Recôncavo (Maracangalha Formation, Caruaçu Member) basins. The mono-, sesqui- and diterpenoids in the extracts were used as chemosystematic markers when compared with terpenoids in extant conifers. The compounds were mainly diterpenoids and their degradation products from the labdane, podocarpane, pimarane and isopimarane classes, in addition to paraffins, methoxyphenols and carboxylic acids. Tetracyclic diterpenoids such as phyllocladane, kaurenol and kauranol were also present. The biomarker compositions are certainly typical for conifers and, given the absence of triterpenoids and diterpenoids such as ozic acid, angiosperms can be excluded as a botanical source. The absence of phenolic diterpenoids (ferruginol, totarol) and their derivatives excludes podocarpaceous affinities for the ambers from the Amazonas and Araripe basins. The fossil records of the embedding sediments (e.g. Araucariaceae pollen and leaves) support the proposal of an Araucariacae origin for these ambers, but Cupressaceae and Cheirolepidiaceae cannot be excluded. On the other hand, the presence of phyllocladane and kaurane derivatives is evidence for Araucariaceae or Podocarpaceae origins for the amber from the Recôncavo basin, but Cupressaceae cannot be excluded.  相似文献   

Formulation of a tropical town energy budget (t-TEB) scheme     

Hugo Abi Karam  Augusto José Pereira Filho  Valery Masson  Joël Noilhan  Edson Pereira Marques Filho 《Theoretical and Applied Climatology》2010,101(1-2):109-120

This work describes the tropical town energy budget (t-TEB) scheme addressed to simulate the diurnal occurrence of the urban heat island (UHI) as observed in the Metropolitan Area of Rio de Janeiro (MARJ; ?22° S; ?44° W) in Brazil. Reasoning about the tropical urban climate have guided the scheme implementation, starting from the original equations from Masson (Bound-Lay Meteorol 94:357–397, 2000). The modifications include (a) local scaling approaches for obtaining flux–gradient relationships in the roughness sub-layer, (b) the Monin-Obukhov similarity framework in the inertial sub-layer, (c) increasing aerodynamic conductance toward more unstable conditions, and (d) a modified urban subsurface drainage system to transfer the intercepted rainwater by roofs to the roads. Simulations along 2007 for the MARJ are obtained and compared with the climatology. The t-TEB simulation is consistent with the observations, suggesting that the timing and dynamics of the UHI in tropical cities could vary significantly from the familiar patterns observed in mid-latitude cities—with the peak heat island intensity occurring in the morning than at night. The simulations are suggesting that the thermal phase shift of this tropical diurnal UHI is a response of the surface energy budget to the large amount of solar radiation, intense evapotranspiration, and thermal response of the vegetated surfaces over a very humid soil layer.  相似文献   

Numerical modelling of the hydro‐chemo‐mechanical behaviour of geomaterials in the context of CO2 injection     

V. Vallin  J.M. Pereira  A. Fabbri  H. Wong 《国际地质力学数值与分析法杂志》2013,37(17):3052-3069

Safety assessment of geosequestration of CO₂ into deep saline aquifers requires a precise understanding of the study of hydro‐chemo‐mechanical couplings occurring in the rocks and the cement well. To this aim, a coupled chemo‐poromechanical model has been developed and implemented into a research code well‐suited to the resolution of fully coupled problems. This code is based on the finite volume methods. In a 1D axisymmetrical configuration, this study aims to simulate the chemo‐poromechanical behaviour of a system composed by the cement well and the caprock during CO₂ injection. Major chemical reactions of carbonation occurring into cement paste and rocks are considered in order to evaluate the consequences of the presence of CO₂ on the amount of dissolved matrix and precipitated calcium carbonates. The dissolution of the solid matrix is taken into account through the use of a chemical porosity. Matrix leaching and carbonation lead, as expected, to important variations of porosity, permeability and to alterations of transport properties and mechanical stiffness. These results justify the importance of considering a coupled analysis accounting for the main chemical reactions. It is worth noting that the modelling framework proposed in the present study could be extended to model the chemo‐poromechanical behaviour of the reservoir rock and the caprock when subjected to the presence of an acidic pore fluid (CO₂‐rich brine). Copyright © 2013 John Wiley & Sons, Ltd.  相似文献