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排序方式: 共有247条查询结果,搜索用时 15 毫秒
71.
Gérsica Moraes Nogueira da Silva Renata Maria C. M. de Oliveira Carvalho Ana Carla Asfora El-Deir Maria do Carmo Martins Sobral Marianna Siegmund-Schultze 《Regional Environmental Change》2018,18(7):1889-1899
Currently, artisanal fisheries in fresh water reservoirs have been losing ground to commercial fish farming and a great deal of fishery resources are being threatened by human interventions, such as reservoir management and increasing net-cage aquaculture. This study aims to understand the impacts of environmental changes on fishery resources and analyse the migratory fish breeding season as a missing link for fishery management in the semi-arid area of the São Francisco River Basin. Among the 870 fishermen operating in the Pernambuco part of the Itaparica Reservoir, 10% were interviewed and affirmed that fish stocks have been compromised due to the closed fishing period’s incoherence, exotic species insertion, and changes to the river flow caused by reservoir construction and operation. A significant correlation was observed between the Reproductive Activity Index (RAI) and precipitation (p?=?0.745) as well as between the RAI and the river’s flow (p?=??0.909). This shows how important it is to consider both the semi-arid climate setting and reservoir operation in determining the closed period which should safeguard fish reproduction. Monitoring the fish reproduction period and research on the reproductive biology of native fish species is needed in the São Francisco River Basin’s different stretches in order to guarantee valuable fish stocks and fisheries maintenance. Integrated action between the fish resource users, civil society, and federal bodies/agencies is essential in order to mitigate impacts and improve fish production systems, not only in Brazil, but in other regions experiencing a similar scenario. 相似文献
72.
73.
Edwin D. Bailey 《Journal of the American Water Resources Association》1979,15(3):801-811
ABSTRACT: The Tucson area is totally dependent on ground water, which is in increasingly short supply due to excessive overdrafts. Tucson area waste water treatment plants discharge material quantities of secondary effluent downstream, which is lost to evapotranspiration and recharge of the ground water basin. The city and the four large mining companies who share the common Santa Cruz basin ground water, recognized the common water supply problem and agreed to fund a feasibility study for mining process use of the effluent to partly alleviate the overdraft of ground water. The study analyzed the projected waste water effluent resources, potential mining company demand for waste water effluent and possible interface of an effluent delivery facility with the proposed Central Arizona Project. The effluent resources were analyzed with respect to potential demand. An optimum alignment was selected. An optimum system was detailed through design schematics, amortized cost and finance requirements, and an implementation schedule. It was concluded that a waste water effluent delivery facility could be implemented which would utilize reclaimed effluent in quantities approximating 35 percent of basin overdraft and which would provide revenue for full cost recovery over a 20 year operation period. The mining companies are studying the internal economic impacts of the project. 相似文献
74.
75.
Bob Bailey 《生态毒理学报》2001,23(3):12-15
联合国环境规划署(UNEP)和全球环境组织正在中欧和和东欧发起"EMPRESS”(有关能源管理和执行的节约计划)计划.这项计划集中了两个既定的提高能源效率的手段--能源服务机构(ESCOs)和监测与确定指标系统(M&T)--,以便通过低成本手段以及改善管理方法减少二氧化碳的排放执行费用将由如此节约能源后产生的效益承担. 相似文献
76.
Use of precision agriculture technology to investigate spatial variability in nitrogen yields in cut grassland 总被引:4,自引:0,他引:4
Spatial variability in N uptake and utilisation by swards within uniformly managed field units could be responsible for a significant proportion of the NH3, N2O, NO3- and NOx (NO and NO2) 'pollutants' generated by agriculture and released to the environment. An investigation was commenced, therefore, to quantify, map and explain the spatial variability in sward N yield in a 'large' silage field and to assess the potential for managing this variability using some of the latest precision agriculture technology. Sward dry matter (DM) and N yields were predicted from the results of plant tissue analyses using mathematical models. Sward N yields were found to vary greatly across the field seemingly because of differences in net soil N mineralisation, but the pattern of variability appeared to remain constant with time. Conventional soil analysis of a range of soil chemical and physical properties, however, failed to explain this variability. It was concluded that the N-yield distribution map might be used in place of soil analysis as the basis for varying the rates of N application to different parts of the field with the twin objectives of maximising fertiliser use efficiency and minimising N emissions to air and water. 相似文献
77.
P. W. Glynn S. B. Colley J. L. Maté J. Cortés H. M. Guzman R. L. Bailey J. S. Feingold I. C. Enochs 《Marine Biology》2008,153(4):529-544
The reproductive ecology of Tubastraea coccinea Lesson, an azooxanthellate tropical scleractinian coral, was studied over various periods from 1985 to 2006 at four principal
eastern Pacific locations in Costa Rica, Panamá, and the Galápagos Islands (Ecuador). This small (polyp diameter 0.8–1.0 cm),
relatively cryptic species produced ova and planulae year round, including colonies with as few as 2–10 polyps. Of 424 colonies
examined histologically, 13.7% contained both ova and sperm. Mature ova varied in diameter from ∼300 to 800 μm and the time
from spawning and fertilization of oocytes to release of brooded planulae was about 6 weeks. Planulae were 0.5–1.5 mm long
and they settled and metamorphosed on a variety of substrates after 1–3 days. Spermaries, though more difficult to distinguish
in histological sections, were present throughout the year. Spent spermaries were never observed in sections, but several
colonies in Panamá and the Galápagos Islands released sperm from night one to night five after full moon, indicating the potential
for cross-fertilization among colonies. Planula release was observed at Uva Island (Panamá) in March, May, June, and July,
and in general planula presence was higher at warm ocean temperatures at all sites, whether or not the sites were influenced
by seasonal upwelling. Annual fecundity estimates for T. coccinea are comparable with other high fecundity brooding species, including the zooxanthellate Porites panamensis, with which it co-occurs in Panamá. Tubastraea coccinea is widely distributed in the tropical Indo-Pacific and has colonized substrates in the western Atlantic. In addition to the
reproductive characteristics described in the present study, other features of the biology of T. coccinea, such as an ability to withstand conditions that produce bleaching and mortality in zooxanthellate species, may account for
its widespread, low-latitude distribution in multiple oceans.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
An erratum to this article can be found at 相似文献
78.
79.
Silva Lídia Gaudêncio Ribeiro Costa Elizângela Pinheiro Starling Maria Clara Vieira Martins dos Santos Azevedo Taíza Bottrel Sue Ellen Costa Pereira Renata Oliveira Sanson Ananda Lima Afonso Robson José Cassia Franco Amorim Camila C. 《Environmental science and pollution research international》2021,28(19):24067-24078
Environmental Science and Pollution Research - The goal of this work was to evaluate the performance of the LED irradiated photo-Fenton process on the removal of (i) estrogenic activity and (ii)... 相似文献
80.
Renata B. S. Oliveira Riccardo Mugnai Carolina M. Castro Darcilio F. Baptista 《Environmental monitoring and assessment》2011,175(1-4):75-85
The purpose of this study was to establish a subsampling procedure for benthic macroinvertebrates to aid in the development of a multimetric index to assess the biological condition of streams. Data from six streams that are considered minimally impaired were used. Subsampling was done using a device divided into 24 quadrats. The sediment from each quadrat was sorted, and all organisms were removed and identified. Richness metrics were the most affected by subsample size. Relative-abundance metrics were the most stable, proving that the sample was well distributed throughout the tray and abundance proportions were maintained. The results showed that the macroinvertebrate assemblage present in the six quadrats was similar to that present in the full sample. These analyses indicated that six quadrats, randomly designated, with a minimum of 200 collected specimens could be used in place of the full sample. In routine water management, managing time and costs are a major challenge; therefore, this type of simplification is absolutely necessary to ensure that a biomonitoring tool is useful for practical applications. 相似文献