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结果 1811-1820 的 4,367
Chronology of anthropogenic impacts reconstructed from sediment records of trace metals and Pb isotopes in Todos os Santos Bay (NE Brazil) 全文
2017
Andrade, R.L.B. | Hatje, V. | Masqué, P. | Zurbrick, C.M. | Boyle, E.A. | Santos, W.P.C.
The evolution of the impacts of anthropogenic activities in Todos os Santos Bay was evaluated by profiles of trace metals and Pb isotopes determined in sediment cores. Fluxes of metals increased up to 12, 4 and 2 times for Cu, Pb, and Zn, respectively, compared to those recorded in the beginning of the 20th century. Stable Pb isotopes identified a decommissioned lead smelter and burning of fossil fuels as the main sources of Pb. Most metals showed minor to moderate enrichment factors (EF<4), but Cu and Pb were highly enriched (EF=28 and 6, respectively) at the Aratu harbor. Temporal changes in sediments were associated to different activities, namely Pb smelting, burning of fossil fuels, maritime traffic, petroleum related activities, inputs of domestic effluents, and changes in land uses. The effects of the implementation of environmental policies to improve the waters of the bay could not be identified in the evaluated cores.
显示更多 [+] 显示较少 [-]Effects of aerobic respiration and nitrification on dissolved inorganic nitrogen and carbon dioxide in human-perturbed eastern Jiaozhou Bay, China 全文
2017
Han, Ping | Li, Yunxiao | Yang, Xufeng | Xue, Liang | Zhang, Longjun
Aerobic respiration and nitrification are important processes for dissolved inorganic nitrogen (DIN) composition change and CO2 production in human-perturbed coastal waters. On-site incubations and field investigations were conducted in the eastern Jiaozhou Bay, a high-urbanization region, from May to August 2014. Results show that aerobic respiration rates reached 15.58μmolO2L−1d−1, and NH4+ and NO2− oxidation rates were 0.53 and 0.13μmolNL−1d−1, respectively, in the human-perturbed northeastern area. The intense aerobic respiration there contributed to high-concentration NH4+, and meanwhile caused a pH decrease of 0.042units and a pCO2 increase of 166μatm per day. Moreover, the linear relationship between excess CO2 and apparent oxygen utilization suggested that the excess CO2 in the entire eastern Jiaozhou Bay was mainly from the aerobic respiration. This study may help us better understand the role of aerobic respiration in DIN composition and CO2 sink/source pattern in coastal waters.
显示更多 [+] 显示较少 [-]New Particle Formation and Growth Mechanisms in Highly Polluted Environments 全文
2017
You, Huan | Ren, Lili | Kanawade, Vijay P.
New particle formation (NPF) has been expected to be less favored in the polluted atmosphere than in the clean atmosphere. However, highly polluted regions in developing countries like China and India are becoming hot spots of NPF. Understanding nucleation and growth mechanisms of aerosol particles in polluted environments have important implications in their global climate impact and health effect. This paper reviewed recent publications from atmospheric field and laboratory measurements under conditions relevant to the polluted atmosphere. NPF probability in polluted environments was discussed by exploring the uncertainties in coagulation sink and growth rate estimations. Future directions and challenges in understanding NPF in highly polluted environments are presented.
显示更多 [+] 显示较少 [-]The relation between columnar and surface aerosol optical properties in a background environment 全文
2017
Szczepanik, D. | Markowicz, K.M.
This work presents the results of observation and the numerical simulation relationship between columnar and surface aerosol optical properties. The presented data include sun photometer nephelometer, aethalometer, and ceilometer observation, as well as the Navy Aerosol Analysis and Prediction System (NAAPS) re-analysis obtained between 2013 and 2016. Measurements were made in Strzyzow station (south-eastern part of Poland), which belongs to the AERONET and Poland-AOD network. Observation and simulation data show that the correlation coefficient between aerosol optical depth and surface aerosol scattering coefficient depends on the averaging period. For the monthly mean both parameters are negatively correlated as a result of the seasonal variability of anthropogenic emission in Central Europe and long-range transport of natural aerosol, as well as the change of the meteorological conditions. Reduction of the averaging time leads to an increase in the correlation coefficient, which is almost zero for a 10-day period and 0.4 ± 0.05 when the six-hour data are selected. In addition, the correlation between columnar and surface aerosol optical properties shows significant variation with surface temperature gradient. During convective conditions the correlation coefficient between aerosol optical depth and aerosol scattering coefficient is as much as 0.89 ± 0.03 while during inversion it is approximately 0.48 ± 0.08.
显示更多 [+] 显示较少 [-]Microplastics as a vector for the transport of the bacterial fish pathogen species Aeromonas salmonicida 全文
2017
Viršek, Manca Kovač | Lovšin, Marija Nika | Koren, Špela | Kržan, Andrej | Peterlin, Monika
Microplastics is widespread in the marine environment where it can cause numerous negative effects. It can provide space for the growth of organisms and serves as a vector for the long distance transfer of marine microorganisms. In this study, we examined the sea surface concentrations of microplastics in the North Adriatic and characterized bacterial communities living on the microplastics. DNA from microplastics particles was isolated by three different methods, followed by PCR amplification of 16S rDNA, clone libraries preparation and phylogenetic analysis. 28 bacterial species were identified on the microplastics particles including Aeromonas spp. and hydrocarbon-degrading bacterial species. Based on the 16S rDNA sequences the pathogenic fish bacteria Aeromonas salmonicida was identified for the first time on microplastics. Because A. salmonicida is responsible for illnesses in fish, it is crucial to get answers if and how microplastics pollution is responsible for spreading of diseases.
显示更多 [+] 显示较少 [-]Fast assessment of bioaccessible metallic contamination in marine sediments 全文
2017
Terán-Baamonde, J. | Carlosena, A. | Soto-Ferreiro, R.M. | Andrade, J.M. | Prada, D.
A fast (16min) procedure to assess the bioaccessible metallic fraction of Cd, Cr, Cu, Ni, Pb and Zn simultaneously extracted (SEM) from marine sediments plus an indirect approach to determine acid volatile sulfides (AVS) are presented. For the extraction process magnetic agitation was compared with ultrasonic stirring (using a bath and a probe), and several stirring times were assayed. The proposed SEM procedure uses an ultrasonic probe and 1mL of HCl. It dramatically minimizes the turnaround time and the residues. AVS were evaluated as the difference between the amounts of sulphur in the solid residue after the extraction and total sulphur in the original sample. These procedures are fast, easy to implement and cost-effective to assess the potential risk posed by metals in marine sediments. They were tested using several CRMs and applied to sediments from two Galician Rias (NW Spain); their SEM-AVS differences indicated no biological risk.
显示更多 [+] 显示较少 [-]Ingestion of marine debris by the White-chinned Petrel (Procellaria aequinoctialis): Is it increasing over time off southern Brazil? 全文
2017
Petry, Maria V. | Benemann, Victória R.F.
Seabirds are amongst the most affected organisms by plastic pollution worldwide. Ingestion of marine debris has been reported in at least 122 species, and owing to the increasing global production and persistence of these anthropogenic materials within the marine environment, it is expected to be a growing problem to the marine fauna. Here we report evidence of an increasing frequency in marine debris ingestion and a decrease in the amount of plastic pellets ingested by White-chinned Petrels attending south Brazilian waters during the last three decades. Future studies comprising large temporal scales and large sample sizes are needed to better understand the trends of marine debris ingestion by seabirds. We expect our findings to highlight the need for prevention policies and mitigation measures to reduce the amount of solid litter in the oceans.
显示更多 [+] 显示较少 [-]The plastic in microplastics: A review 全文
2017
Andrady, A. L. (Anthony L.)
Microplastics [MPs], now a ubiquitous pollutant in the oceans, pose a serious potential threat to marine ecology and has justifiably encouraged focused biological and ecological research attention. But, their generation, fate, fragmentation and their propensity to sorb/release persistent organic pollutants (POPs) are determined by the characteristics of the polymers that constitutes them. Yet, physico-chemical characteristics of the polymers making up the MPs have not received detailed attention in published work. This review assesses the relevance of selected characteristics of plastics that composes the microplastics, to their role as a pollutant with potentially serious ecological impacts. Fragmentation leading to secondary microplastics is also discussed underlining the likelihood of a surface-ablation mechanism that can lead to preferential formation of smaller sized MPs.
显示更多 [+] 显示较少 [-]Trace element exposure of whooper swans (Cygnus cygnus) wintering in a marine lagoon (Swan Lake), northern China 全文
2017
Wang, Feng | Xu, Shaochun | Zhou, Yi | Wang, Pengmei | Zhang, Xiaomei
Trace element poisoning remains a great threat to various waterfowl and waterbirds throughout the world. In this study, we determined the trace element exposure of herbivorous whooper swans (Cygnus cygnus) wintering in Swan Lake (Rongcheng), an important swan protection area in northern China. A total of 70 samples including abiotic factors (seawater, sediments), food sources (seagrass, macroalgae), feathers and feces of whooper swans were collected from the marine lagoon during the winters of 2014/2015 and 2015/2016. Concentrations of Cu, Zn, Pb, Cr, Cd, Hg and As were determined to investigate the trace element exposure of whooper swans wintering in the area. Results showed that there was an increasing trend in sediment trace element concentrations, compared with historical data. The trace element concentrations in swan feces most closely resembled those of Zostera marina leaves, especially for Cd and Cr. The Zn and Hg concentrations in the swan feces (49.57 and 0.01mg/kg, respectively) were lower than the minimum values reported in the literature for other waterfowls, waterbirds and terrestrial birds. However, the concentrations of the other five trace elements fell within the lower and mediate range of values reported for birds across the world. These results suggest that the whooper swans wintering in Swan Lake, Rongcheng are not suffering severe trace element exposure; however, with the increasing input of trace elements to the lagoon, severe adverse impacts may occur in the future, and we therefore suggest that the input of trace elements to this area should be curbed.
显示更多 [+] 显示较少 [-]Restoring rocky intertidal communities: Lessons from a benthic macroalgal ecosystem engineer 全文
2017
Bellgrove, Alecia | McKenzie, Prudence F. | Cameron, Hayley | Pocklington, Jacqueline B.
As coastal population growth increases globally, effective waste management practices are required to protect biodiversity. Water authorities are under increasing pressure to reduce the impact of sewage effluent discharged into the coastal environment and restore disturbed ecosystems. We review the role of benthic macroalgae as ecosystem engineers and focus particularly on the temperate Australasian fucoid Hormosira banksii as a case study for rocky intertidal restoration efforts. Research focussing on the roles of ecosystem engineers is lagging behind restoration research of ecosystem engineers. As such, management decisions are being made without a sound understanding of the ecology of ecosystem engineers. For successful restoration of rocky intertidal shores it is important that we assess the thresholds of engineering traits (discussed herein) and the environmental conditions under which they are important.
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