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Daniellys Alejo Mayra C. Morales Jorge B. de la Torre Ricardo Grau László Bencs René Van Grieken Piet Van Espen Dismey Sosa Vladimir Nuñez 《Environmental monitoring and assessment》2013,185(7):6023-6033
Atmospheric nitrogen dioxide (NO2) and sulfur dioxide (SO2) levels were monitored simultaneously by means of Radiello passive samplers at six sites of Santa Clara city, Cuba, in the cold and the warm seasons in 2010. The dissolved ionic forms of NO2 and SO2 as nitrate and sulfite plus sulfate, respectively, were determined by means of ion chromatography. Analysis of NO2 as nitrite was also performed by UV–Vis spectrophotometry. For NO2, significant t tests show good agreement between the results of IC and UV–Vis methods. The NO2 and SO2 concentrations peaked in the cold season, while their minimum levels were experienced in the warm season. The pollutant levels do not exceed the maximum allowable limit of the Cuban Standard 39:1999, i.e., 40 μg/m3 and 50 μg/m3 for NO2 and SO2, respectively. The lowest pollutant concentrations obtained in the warm season can be attributed to an increase in their removal via precipitation (scavenging) while to the decreased traffic density and industrial emission during the summer holidays (e.g., July and August). 相似文献
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In soft sediment marine communities, fishes frequently bite off extended siphons of buried clams; the consequential shortening
of the siphon is known to reduce burial depth of the clams, secondarily increasing their vulnerability to lethal excavating
predators. In this study, siphon nipping on the yellow clam, Mesodesma mactroides, was simulated by removing the top 6.6–30% of siphons. This caused a burrow reduction in 25–75%, respectively, compared to
control individuals with intact siphons, in field and laboratory trials. To examine subsequent consequences of reduced burial
depth, we exposed nipped and intact clams to potential predators in the laboratory simulating the observed natural clam abundance.
Artificially nipped clams were consumed twice as much as control clams. The present results suggest that sympatric croppers
contribute to the stock recovery failure by facilitation of lethal predation and that re-seeding to increase the local abundance
of M. mactroides should be an essential aspect of conservation efforts in South America. 相似文献
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David W. Watkins Jr. Márcia M. G. Alcoforado de Moraes Heidi Asbjornsen Alex S. Mayer Julian Licata Jose Gutierrez Lopez Thomas G. Pypker Vivianna Gamez Molina Guilherme Fernandes Marques Ana Cristina Guimaraes Carneiro Hector M. Nuñez Hayri Önal Bruna da Nobrega Germano 《Environmental management》2015,56(6):1295-1314
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Hoang Anh Quoc Le Thuy Minh Nguyen Ha My Nu Le Huong Quang Vu Nam Duc Chu Ngoc Chau Dang Giang Huong Minh Minh Tu Binh Takahashi Shin Tran Tri Manh 《Environmental science and pollution research international》2022,29(10):14046-14057
Environmental Science and Pollution Research - The occurrence of nine phthalic acid esters (PAEs) were determined in indoor dust samples collected from vehicle repair shops, waste processing... 相似文献
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John R. Poulsen Cooper Rosin Amelia Meier Emily Mills Chase L. Nuñez Sally E. Koerner Emily Blanchard Jennifer Callejas Sarah Moore Mark Sowers 《Conservation biology》2018,32(3):559-567
Poaching is rapidly extirpating African forest elephants (Loxodonta cyclotis) from most of their historical range, leaving vast areas of elephant‐free tropical forest. Elephants are ecological engineers that create and maintain forest habitat; thus, their loss will have large consequences for the composition and structure of Afrotropical forests. Through a comprehensive literature review, we evaluated the roles of forest elephants in seed dispersal, nutrient recycling, and herbivory and physical damage to predict the cascading ecological effects of their population declines. Loss of seed dispersal by elephants will favor tree species dispersed abiotically and by smaller dispersal agents, and tree species composition will depend on the downstream effects of changes in elephant nutrient cycling and browsing. Loss of trampling and herbivory of seedlings and saplings will result in high tree density with release from browsing pressures. Diminished seed dispersal by elephants and high stem density are likely to reduce the recruitment of large trees and thus increase homogeneity of forest structure and decrease carbon stocks. The loss of ecological services by forest elephants likely means Central African forests will be more like Neotropical forests, from which megafauna were extirpated thousands of years ago. Without intervention, as much as 96% of Central African forests will have modified species composition and structure as elephants are compressed into remaining protected areas. Stopping elephant poaching is an urgent first step to mitigating these effects, but long‐term conservation will require land‐use planning that incorporates elephant habitat into forested landscapes that are being rapidly transformed by industrial agriculture and logging. 相似文献