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181.
Luciana Gnio Ana Sousa Nuno Vaz Joo M. Dias Carlos Barroso 《Journal of Sea Research》2008,59(3):133-143
The effect of low salinity on the survival of recently hatched veliger of the gastropod Nassarius reticulatus (L.) was studied under laboratory conditions at 17 °C ± 1 °C. Significant mortality occurred for salinities ≤ 17 psu and the LS50 (salinity that causes 50% mortality) varied from 14.5 psu to 17.2 psu for exposures between 1 h and 48 h, respectively. The results were included in a mathematical model in order to estimate the mortality of N. reticulatus veliger in Ria de Aveiro under different salinity scenarios determined by numerical simulation. The model predicts a massive mortality of veliger immediately after their eclosion (1 h) in Ria de Aveiro during spring tide when the river input reaches its expected maximum — a situation that has been observed occasionally and may overlap a massive eclosion of veliger in the water. Except in this extreme situation, the mortality in Ria de Aveiro is generally restricted to the upstream limits of the channels. The results indicate that N. reticulatus recruitment in estuaries may strongly depend on the prevailing salinity regime. 相似文献
182.
Maryline Moulin Daniel Aslanian Mikael Evain Anglique Leprêtre Philippe Schnurle Fanny Verrier Joseph Thompson Philippe De Clarens Sylvie Leroy Nuno Dias 《地学学报》2020,32(3):205-214
The Natal Valley, offshore Mozambique, is a key area for understanding the evolution of East Gondwana. Within the scope of the integrated multidisciplinary PAMELA project, we present new wide‐angle seismic data and interpretations, which considerably alter Geoscience paradigms. These data reveal the presence of a 30‐km‐thick crust that we argue to be of continental nature. This falsifies all the most recent palaeo‐reconstructions of the Gondwana. This 30‐km‐thick continental crust 1,000 m below sea level implies a complex history with probable intrusions of mantle‐derived melts in the lower crust, connected to several occurrences of magmatism, which seems to evidence the crucial role of the lower continental crust in passive margin genesis. 相似文献
183.
Sousa OV Macrae A Menezes FG Gomes NC Vieira RH Mendonça-Hagler LC 《Marine pollution bulletin》2006,52(12):1725-1734
The effects of shrimp farm effluents on bacterial communities in mangroves have been infrequently reported. Classic and molecular biology methods were used to survey bacterial communities from four mangroves systems. Water temperature, salinity, pH, total heterotrophic bacteria and maximum probable numbers of Vibrio spp. were investigated. Genetic profiles of bacterial communities were also characterized by polymerase chain reaction (PCR) amplification of eubacterial and Vibrio 16S rDNA using denaturing gradient gel electrophoresis (DGGE). Highest heterotrophic counts were registered in the mangrove not directly polluted by shrimp farming. The Enterobacteriaceae and Chryseomonas luteola dominated the heterotrophic isolates. Vibrio spp. pathogenic to humans and shrimps were identified. Eubacterial genetic profiles suggest a shared community structure independent of mangrove system. Vibrio genetic profiles were mangrove specific. Neither microbial counts nor genetic profiling revealed a significant decrease in species richness associated with shrimp farm effluent. The complex nature of mangrove ecosystems and their microbial communities is discussed. 相似文献
184.
Andrea de Oliveira Cardoso Hilton Silveira Pinto Ana Maria Heuminski de Ávila Pedro Leite da Silva Dias Fabio Ricardo Marin Felipe Pilau 《Theoretical and Applied Climatology》2010,102(3-4):343-350
Weather conditions in critical periods of the vegetative crop development influence crop productivity, thus being a basic parameter for crop forecast. Reliable extended period weather forecasts may contribute to improve the estimation of agricultural productivity. The production of soybean plays an important role in the Brazilian economy, because this country is ranked among the largest producers of soybeans in the world. This culture can be significantly affected by water conditions, depending on the intensity of water deficit. This work explores the role of extended period weather forecasts for estimating soybean productivity in the southern part of Brazil, Passo Fundo, and Londrina (State of Rio Grande do Sul and Paraná, respectively) in the 2005/2006 harvest. The goal was to investigate the possible contribution of precipitation forecasts as a substitute for the use of climatological data on crop forecasts. The results suggest that the use of meteorological forecasts generate more reliable productivity estimates during the growth period than those generated only through climatological information. 相似文献
185.
Cloud condensation nuclei from biomass burning during the Amazonian dry-to-wet transition season 总被引:1,自引:0,他引:1
Jorge Alberto Martins Fábio Luiz T. Gonçalves Carlos A. Morales Gilberto F. Fisch Francisco Geraldo M. Pinheiro João Bosco V. Leal Júnior Carlos J. Oliveira Emerson M. Silva José Carlos P. Oliveira Alexandre A. Costa Maria Assunção F. Silva Dias 《Meteorology and Atmospheric Physics》2009,104(1-2):83-93
Aircraft measurements of cloud condensation nuclei (CCN) during the Large-Scale Biosphere–Atmosphere Experiment in Amazonia (LBA) were conducted over the Southwestern Amazon region in September–October 2002, to emphasize the dry-to-wet transition season. The CCN concentrations were measured for values within the range 0.1–1.0% of supersaturation. The CCN concentration inside the boundary layer revealed a general decreasing trend during the transition from the end of the dry season to the onset of the wet season. Clean and polluted areas showed large differences. The differences were not so strong at high levels in the troposphere and there was evidence supporting the semi-direct aerosol effect in suppressing convection through the evaporation of clouds by aerosol absorption. The measurements also showed a diurnal cycle following biomass burning activity. Although biomass burning was the most important source of CCN, it was seen as a source of relatively efficient CCN, since the increase was significant only at high supersaturations. 相似文献
186.
Stereospondyls survived the Permo-Triassic extinctions in a refuge probably located in the landmass that nowadays comprises Australia. Subsequently, they radiated to other parts of Pangaea, reaching their highest distribution and diversification during the Early Triassic. An incomplete interclavicle from the Caturrita Formation represents their first record in the Upper Triassic of Brazil. Previously, Upper Triassic South American stereospondyls were restricted to Argentina. This new record reinforces a former hypothesis that suggests the presence of a more diverse stereospondyl fauna in South America during the Late Triassic than previously assumed. Additionally, the presence of a stereospondyl and a phytosaur in the Caturrita Formation reinforces the hypothesis of a change to more humid climatic conditions in the Paraná Basin during the Upper Triassic. The record of Early Triassic stereospondyls in South America suggests that they first colonized Brazil and/or Uruguay, spreading from South Africa during the Early Triassic, subsequently reaching Argentina. Up till now, there is no record of Middle Triassic stereospondyls in either Argentina and Brazil, probably due to either taphonomic bias or insufficient prospecting. Despite the lack of direct evidence, one should not dismiss an earlier stereospondyl colonization of Argentina still during the Early or Middle Triassic. 相似文献
187.
We present a new stable isotope mass balance method for measuring the enhanced aqueous solubility of specific organic compounds in the presence of natural dissolved organic matter (DOM). It involves interfacing a standard dissolved organic carbon (DOC) analyzer with a stable isotope ratio monitoring system, is applicable to a wide range of model organic compounds and can be tuned to provide maximum precision for a given range of compound solubility and initial natural DOC concentration. Using 13C-labeled styrene as a model compound, we applied the method to investigate the reactivity of Dismal Swamp DOM as a function of season, nominal molecular size and chemical composition as determined using Fourier Transform Infrared Spectroscopy (FTIR). The solubility enhancement of styrene ranged from 23% to 118% relative to deionized water, while DOC-normalized enhancements varied from about 0.04 to 0.35 μM styrene/μM DOC as a function of season and nominal molecular weight. Statistical analysis of FTIR spectra reveals a strong positive correlation between the styrene concentration and the carboxyl content of the natural DOM. Reactivity differences between high molecular weight (HMW), low molecular weight (LMW) and total DOM samples are consistent with potential variations in their higher order structures. 相似文献
188.
Encarnación Roda-Robles Romeu Vieira Alfonso Pesquera Alexandre Lima 《Mineralogy and Petrology》2010,100(1-2):23-34
Granitic pegmatites are widespread within a schist-metagreywacke complex in the Fregeneda-Almendra area (Central Iberian Zone). They intrude pre-Ordovician metasedimentary rocks and show a zonal distribution relative to the Meda-Penedono-Lumbrales granitic complex, from barren bodies to those enriched in Li, F, Sn, Nb>Ta, P and Be. Based on mineralogical criteria, these pegmatites are classified into three main categories: barren, intermediate and rare-element pegmatites, with each type including various subtypes. Phosphates are present in many pegmatites that usually occur as fine-grained accessory minerals. The most complex association of such minerals includes numerous Fe–Mn phosphates that occur in intermediate pegmatites. Al-phosphates are characteristic of Li-rich pegmatites. Electron microprobe analyses of representative phosphates reflect compositional differences depending on the pegmatite type. The Fe/(Fe+Mn) ratio of phosphates tends to decrease as the evolution degree of the pegmatites increases. 相似文献
189.
Rafael Matias Feltrin João Batista Dias de Paiva Eloiza Maria Cauduro Dias de Paiva Fábio Alex Beling 《水文研究》2011,25(15):2321-2328
This study aims at monitoring the behaviour of the rainfall, runoff, drainage, soil water storage, and evapotranspiration variables involved in the water balance measured by lysimeter data. The evaluation of the water balance considered different time scales, where the components were monitored daily and in 10‐day accumulated period intervals. The results demonstrated that in wet periods the soil water content was greater at a depth of 10 cm, whereas in the dry periods a greater concentration was observed at 70 cm depth. At the depth of 30 cm, the lowest values of soil water content were observed for both wet and dry periods. The results, obtained through the use of tensiometers and time domain reflectometry installed internally and externally to the lysimeter, were very close, which was more noticeable during the periods of lower water loss by the soil. The water balance, calculated from the lysimeter data, demonstrated that 70% of the total rainfall was lost by the process of evapotranspiration. The drainage accounted for 27·5% of the precipitated water, highlighting the fact that this component should not be disregarded in the water balance calculation. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
190.
Francisco José da Silva Dias Luiz Drude Lacerda Rozane Valente Marins Francisco Carlos Fernandes de Paula 《水文研究》2011,25(14):2188-2201
This work quantifies, using ADP and rating curve techniques, the instantaneous outflows at estuarine interfaces: higher to middle estuary and middle to lower estuary, in two medium‐sized watersheds (72 000 and 66 000 km2 of area, respectively), the Jaguaribe and Contas Rivers located in the northeastern (semi‐arid) and eastern (tropical humid) Brazilian coasts, respectively. Results from ADP showed that the net water balances show the Contas River as a net water exporter, whereas the Jaguaribe River Estuary is a net water importer. At the Jaguaribe Estuary, water retention during flood tide contributes to 58% of the total volume transferred during the ebb tide from the middle to lower estuary. However, 42% of the total water volume (452 m3 s?1) that entered during flood tide is retained in the middle estuary. In the Contas River, 90% of the total water is retained during the flood tide contributing to the volume transported in the ebb tide from the middle to the lower estuary. Outflows obtained with the rating curve method for the Contas and Jaguaribe Rivers were uniform through time due to river flow normalization by dams in both basins. Estimated outflows with this method are about 65% (Contas) and 95% (Jaguaribe) lower compared to outflows obtained with ADP. This suggests that the outflows obtained with the rating curve method underestimate the net water balance in both systems, particularly in the Jaguaribe River under a semi‐arid climate. This underestimation is somewhat decreased due to wetter conditions in the Contas River basin. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献