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Resultados 1361-1370 de 4,308
Evaluation on island ecological vulnerability and its spatial heterogeneity Texto completo
2017
Ji, Yuan | Shi, Honghua | Wang, Yuanyuan | Guo, Zhen | Wang, Enkang
The evaluation on island ecological vulnerability (IEV) can help reveal the comprehensive characteristics of the island ecosystem and provide reference for controlling human activities on islands. An IEV evaluation model which reflects the land–sea dual features, natural and anthropogenic attributes, and spatial heterogeneity of the island ecosystem was established, and the southern islands of Miaodao Archipelago in North China were taken as the study area. The IEV, its spatial heterogeneity, and its sensitivities to the evaluation elements were analyzed. Results indicated that the IEV was in status of mild vulnerability in the archipelago scale, and population pressure, ecosystem productivity, environmental quality, landscape pattern, and economic development were the sensitive elements. The IEV showed significant spatial heterogeneities both in land and surrounding waters sub-ecosystems. Construction scale control, optimization of development allocation, improvement of exploitation methods, and reasonable ecological construction are important measures to control the IEV.
Mostrar más [+] Menos [-]Quantifying the particulate matter accumulation on leaf surfaces of urban plants in Beijing, China Texto completo
2017
Shi, Junna | Zhang, Gang | An, Hailong | Yin, Weilun | Xia, Xinli
Particulate matter is potentially harmful to human health but green tree species act as air filters to adhere these particulates. The elemental composition, number density, and size fractions of particles on leaf surfaces of 14 urban green from Xizhimen overpass and the Olympic Forest Park in Beijing, China were examined by scanning electron microscopy and X-ray energy dispersive spectrometry. Particles that accumulated on leaves were comprised mainly of C, O, Si, Ca, Fe, and Pb. The number density of particles was 50,961.5 mm−2, and 52.9% and 25% of the particles were submicron (<1 μm) and fine (<2.5 μm), respectively. The densities and size fractions of the particles deposited on the adaxial and abaxial side of leaves were significantly different, and 24% of the particles were deposited on the abaxial side of leaves. The densities of the particles in four size fractions differed significantly among the species at the two sampling sites. Salix matsudana, Euonymus japonicus, Magnolia denudate, Sophora japonica, Amygdalus persica, and Salix babylonica efficiently captured all particle sizes on their leaf surfaces. S. matsudana, E. japonicus, M. denudate, S. japonica, Fraxinus chinensis, and Ginkgo biloba efficiently captured submicron and fine particles, which can have serious effects on human health. These differences among species provide more insight into the sink capacity of green tree species, and the efficiencies of plant species for trapping particulates can be used to guide urban tree planning and decrease air pollution.
Mostrar más [+] Menos [-]Benchmark dynamics in the environmental performance of ports Texto completo
2017
Puig, Martí | Michail, Antonis | Wooldridge, Chris | Darbra, Rosa Mari
This paper analyses the 2016 environmental benchmark performance of the port sector, based on a wide representation of EcoPorts members. This is the fifth time that this study has been conducted as an initiative of the European Sea Ports Organisation (ESPO). The data and results are derived from the Self-Diagnosis Method (SDM), a concise checklist against which port managers can self-assess the environmental management of their port in relation to the performance of the EcoPorts membership. The SDM tool was developed in the framework of the ECOPORTS project (2002–2005) and it is managed by ESPO. A total number of 91 ports from 20 different European Maritime States contributed to this evaluation. The main results are that air quality remains as the top environmental priority of the respondent ports, followed by energy consumption and noise.In terms of environmental management, the study confirms that key components are commonly implemented in the majority of European ports. 94% of contributing ports have a designated environmental manager, 92% own an environmental policy and 82% implement an environmental monitoring program. Waste is identified as the most monitored issue in ports (80%), followed by energy consumption (73%) and water quality (70%).
Mostrar más [+] Menos [-]Trichodesmium blooms and warm-core ocean surface features in the Arabian Sea and the Bay of Bengal Texto completo
2017
Jyothibabu, R. | Karnan, C. | Jagadeesan, L. | Arunpandi, N. | Pandiarajan, R.S. | Muraleedharan, K.R. | Balachandran, K.K.
Trichodesmium is a bloom-forming, diazotrophic, non-heterocystous cyanobacteria widely distributed in the warmer oceans, and their bloom is considered a ‘biological indication’ of stratification and nitrogen limitation in the ocean surface layer. In the first part of this paper, based on the retrospective analyses of the ocean surface mesoscale features associated with 59 Trichodesmium bloom incidences recorded in the past, 32 from the Arabian Sea and the Bay of Bengal, and 27 from the rest of the world, we have showed that warm-core features have an inducing effect on bloom formation. In the second part, we have considered the environmental preferences of Trichodesmium bloom based on laboratory and field studies across the globe, and proposed a view about how warm-core features could provide an inducing pre-requisite condition for the bloom formation in the Arabian Sea and the Bay of Bengal. Proposed that the subsurface waters of warm-core features maintain more likely chances for the conducive nutrient and light conditions required for the triggering of the blooms.
Mostrar más [+] Menos [-]Microplastics in gut contents of coastal freshwater fish from Río de la Plata estuary Texto completo
2017
Pazos, Rocío S. | Maiztegui, Tomás | Colautti, Darío C. | Paracampo, Ariel H. | Gómez, Nora
The presence of microplastics (MPs) in gut contents of coastal freshwater fish of the Rio de la Plata estuary was studied. Samples were taken in six sites where 87 fish belonging to 11 species and four feeding habits were captured. Presence of MPs was verified in the 100% of fish. The fibres represented the 96% of MPs found. The number of MPs in gut contents was significantly higher close to sewage discharge. There was not found relationship between number of MPs and fish length, weight or feeding habit. The spatial differences in mean number of MPs in fish observed in this study, suggest that environmental availability of MPs could be of great importance to explain the differences found among sampling sites analysed. This work represents the first study about the interaction between MPs and aquatic organisms in this important estuarine ecosystem of South America.
Mostrar más [+] Menos [-]Blood cadmium and metallothionein concentrations in females of two sympatric pinnipeds species Texto completo
2017
Polizzi, P. | Romero, M.B. | Chiodi Boudet, L.N. | Ponce de León, A. | Medici, S. | Costas, A. | Rodríguez, D. | Gerpe, M.
Otaria flavescens (SASL) and Arctocephalus australis (SAFS) are endemic of South America. The aims were to assess Cd concentrations in red blood cells (RBC) and plasma from free living females of both species; and to establish metallothioneins (MT) levels in blood fractions and the possible relationship between MTs and Cd. Blood of fifteen SASL and eight SAFS females from Isla de Lobos were analyzed (years 2010–2011). All animals showed Cd levels above the detection limit. Cd concentrations on SAFS were higher than those of SASL, however, no significant differences were observed on metal concentrations between cell fractions by species. Metal levels were associated with a natural presence and ecological-trophic habits of the prey items. On SASL the MT concentrations between fractions were similar; whereas, SAFS plasma concentrations were higher than RBC. The results reported constitute the first information on Cd and MT blood levels in these species.
Mostrar más [+] Menos [-]Continuous monitoring of noise levels in the Gulf of Catania (Ionian Sea). Study of correlation with ship traffic Texto completo
2017
Viola, S. | Grammauta, R. | Sciacca, V. | Bellia, G. | Beranzoli, L. | Buscaino, G. | Caruso, Fabbio | Chierici, F. | Cuttone, G. | D’Amico, A. | De Luca, V. | Embriaco, D. | Favali, P. | Giovanetti, G. | Marinaro, G. | Mazzola, S. | Filiciotto, F. | Pavan, G. | Pellegrino, C. | Pulvirenti, S. | Simeone, F. | Speziale, F. | Riccobene, G.
Acoustic noise levels were measured in the Gulf of Catania (Ionian Sea) from July 2012 to May 2013 by a low frequency (<1000Hz) hydrophone, installed on board the NEMO-SN1 multidisciplinary observatory. NEMO-SN1 is a cabled node of EMSO-ERIC, which was deployed at a water depth of 2100m, 25km off Catania. The study area is characterized by the proximity of mid-size harbors and shipping lanes. Measured noise levels were correlated with the passage of ships tracked with a dedicated AIS antenna. Noise power was measured in the frequency range between 10Hz and 1000Hz. Experimental data were compared with the results of a fast numerical model based on AIS data to evaluate the contribution of shipping noise in six consecutive 1/3 octave frequency bands, including the 1/3 octave frequency bands centered at 63Hz and 125Hz, indicated by the Marine Strategy Framework Directive (2008/56/EC).
Mostrar más [+] Menos [-]Use of multiple functional traits of protozoa for bioassessment of marine pollution Texto completo
2017
Zhong, Xiaoxiao | Xu, Guangjian | Xu, Henglong
Ecological parameters based on multiply functional traits have many advantages for monitoring programs by reducing “signal to noise” ratios of observed species data. To identify potential indicators for bioassessment of marine pollution in function space, the functional patterns of protozoan communities and relationships with environmental changes were studied in coastal waters of the Yellow Sea during a 1-year period. The results showed that: (1) the spatial variability in functional trait distributions of the protozoa was significantly associated with changes in environmental variables, especially chemical oxygen demand (COD) and nutrients on spatial scale; (2) the functional traits, especially food resources and feeding type, were significantly correlated with COD and nutrients; and (3) the functional diversity indices were generally related to nutrients or COD. Based on the results, we suggest that the functional traits and diversity indices of protozoan communities may be used as more effective indicators for bioassessment of marine pollution.
Mostrar más [+] Menos [-]Dispersal and assimilation of an aquaculture waste subsidy in a low productivity coastal environment Texto completo
2017
White, C.A. | Nichols, P.D. | Ross, D.J. | Dempster, T.
To understand dispersal and assimilation of aquaculture waste subsidies in a naturally low-productivity environment, we applied a novel, rapid transmethylation technique to analyse sediment and biota fatty acid composition. This technique was initially validated at Atlantic salmon farms in Macquarie Harbour, Australia, where sediments were collected at farm and control locations. Subsequently, sediment, benthic polychaete and zooplankton were sampled at sites 0, 50, 250, 500 and 1000m distant from multiple cages. Results demonstrated an acute deposition zone up to 50m from cages and a diffuse zone extending 500m from cages. Changes in sediment concentration of linoleic acid, oleic acid and total fatty acids were effective tracers of farm deposition. Bacterial biomarkers indicated that aquaculture waste stimulates bacterial productivity in sediments, with elevated biomarker concentrations also detected in benthic polychaetes. Overall, fatty acid analysis was a sensitive technique to characterize the benthic footprint of aquaculture influence.
Mostrar más [+] Menos [-]Investigating Bermuda's pollution history through stable isotope analyses of modern and museum-held gorgonian corals Texto completo
2017
Baker, David M. | Murdoch, Thaddeus J.T. | Conti-Jerpe, Inga | Fogel, Marilyn
For centuries, Bermuda has been challenged with wastewater management for the protection of human and environmental health. By quantifying the δ15N of the common sea fan Gorgonia ventalina sampled from 30 sites throughout Bermuda we show that sewage-derived nitrogen is detectable on nearshore coral reefs and declines across the lagoon to the outer rim. We also sampled gorgonians from two museum collections representing a 50y time-series (1958–2008). These samples revealed an increase in δ15N of >4.0‰ until the mid-1970s, after which δ15N values slowly declined by ~2.0‰. A δ15N chronology from a gorgonian skeleton exhibited a similar decline over the last 30–40years of approximately 0.6‰. We conclude that policies have been effective in reducing sewage impacts to Bermudian reefs. However, significant sources of sewage pollution persist and are likely have a strong impact on harbor and nearshore coral communities and human health.
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