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Результаты 1301-1310 из 4,307
How the dispersant Corexit impacts the formation of sinking marine oil snow Полный текст
2017
Passow, Uta | Sweet, Julia | Quigg, Antonietta
The vertical transport of sinking marine oil snow (MOS) and oil-sediment aggregations (OSA) during the Deepwater Horizon (DwH) spill contributed appreciably to the unexpected, and exceptional accumulation of oil on the seafloor. However, the role of the dispersant Corexit in mediating oil-sedimentation is still controversial. Here we demonstrate that the formation of diatom MOS is enhanced by chemically undispersed oil, but inhibited by Corexit-dispersed oil. Nevertheless, the sedimentation rate of oil may at times be enhanced by Corexit application, because of an elevated oil content per aggregate when Corexit is used. A conceptual framework explains the seemingly contradictory effects of Corexit application on the sedimentation of oil and marine particles. The redistribution of oil has central ecological implications, and future decisions on mediating measures or damage assessment will have to take the formation of sinking, oil-laden, marine snow into account.
Показать больше [+] Меньше [-]Biodiversity hotspot for marine invertebrates around the Dokdo, East Sea, Korea: Ecological checklist revisited Полный текст
2017
Song, Sung Joon | Park, Jinsoon | Ryu, Jongseong | Rho, Hyun Soo | Kim, Wŏn | Khim, Jong Seong
We extensively reviewed the macrozoobenthos around Dokdo, Korea, by analyzing metadata collected over the past 50years. The Dokdo macrozoobenthos was represented by 578 species belonging to 243 families from 12 phyla, where four major phyla (or classes) collectively accounted for 86% to total. Mollusks, arthropods, and cnidarians were semi-equally occurred in intertidal and subtidal areas, while polychetes dominated the subtidal zone. The northern most region of Dokdo had the greatest biodiversity (173 species). The taxonomic distinctness analysis (delta+) indicated a close association between species by region, although the number of species varied greatly. About half of the species did not occur cross the locations (n=20), indicating strong habitat preferences of Dokdo macrofaunal assemblages. Overall, the diversity of Dokdo was greater than that of Ulleung Island (east coast), but comparable to that of the well-developed tidal flats in the western Korean waters, highlighting its status as a biodiversity hotspot.
Показать больше [+] Меньше [-]New Particle Formation and Growth Mechanisms in Highly Polluted Environments Полный текст
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.
Показать больше [+] Меньше [-]Coastal dynamics vs beach users attitudes and perceptions to enhance environmental conservation and management effectiveness Полный текст
2017
Aretano, Roberta | Parlagreco, Luca | Semeraro, Teodoro | Zurlini, Giovanni | Petrosillo, Irene
This work carries out a landscape analysis for the last 60years to compare the degree of preservation of two areas on the same Italian coastline characterized by different environmental protection levels: a National designated protected areas and a highly tourist coastal destination. The conversion of natural land-covers into human land uses were detected for protected and unprotected coastal stretches highlighting that the only establishment of a protected area is not enough to stem undesirable land-use outcomes. A survey analysis was also conducted to assess attitudes of beach users and to evaluate their perception of natural habitats, beach and coastal water quality, and coastal dynamic over time. The results of 2071 questionnaires showed that there is similarity between subjective and objective data. However, several beach users perceived a bad quality of coastal water in the legally unprotected coastal area. The implications from a planning and management perspective are discussed.
Показать больше [+] Меньше [-]Spatio-temporal variation and influence factors of PM2.5 concentrations in China from 1998 to 2014 Полный текст
2017
Lu, Debin | Xu, Jianhua | Yang, Dongyang | Zhao, Jianan
Based on the remote sensing retrieval of PM2.5 concentration data in the long-time series, both the linear regression and grey system correlation analysis methods were employed to analyze the spatial and temporal pattern, variation trend and the main influencing factors of PM2.5 concentration in China from 1998 to 2014. The results showed that only 16.21%–24.67% of the land area in China PM2.5 concentrations reached the annual average criterion value of 10 μg/m3 set by the World Health Organization (WHO) in 1998–2014; the PM2.5 concentrations were greater than 95 μg/m3 mainly in Xinjiang Taklimakan Desert, west of Tianjin and the central region of Hebei. PM2.5 concentration was less than 10 μg/m3 mainly in Tibet, western Sichuan, northeastern Yunnan, Taiwan, northern Xinjiang, northern Inner Mongolia and northwest of Heilongjiang. High PM2.5 concentration in the northwest of China was mainly affected by sand and dust, while it was mainly caused by human activities in the eastern region. Except for Taiwan, low PM2.5 concentration areas were mainly located in the economically backward regions. The positive indicators in highly correlation with PM2.5 concentration include the average temperature, the proportion of primary and secondary industry to GDP, industrial consumption, the proportion of fulfilled amount of investment in real estate development to GDP, SO2 emissions and population density. The negative indicators in highly correlation with PM2.5 concentration include the average precipitation, the average wind velocity, the proportion of the tertiary industry to GDP, and the greening coverage rate of the built-up areas.
Показать больше [+] Меньше [-]The relation between columnar and surface aerosol optical properties in a background environment Полный текст
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.
Показать больше [+] Меньше [-]Metal pollution in Al-Khobar seawater, Arabian Gulf, Saudi Arabia Полный текст
2017
Alharbi, Talal | Alfaifi, Hussain | El-Sorogy, Abdelbaset
In order to assess heavy metals pollution along the Al-Khobar coastline, 30 seawater samples and 15 sediment ones were collected for Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Hg and Pb analysis by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The analysis indicated a southward decreasing pattern in most heavy metal concentrations and the average values of Zn, Fe, Mn, Cu, As and Cr were higher than the ones reported from some worldwide seas and gulfs. Most of the highest levels were recorded within the bays and were related with in situ under sediments especially that composed of clays and very fine sands, and in localities characterized with anthropogenic activities like landfilling, desalination plants, fishing boats, oil spills and solid rubbish. The results of the present study provide useful background for further marine investigation and management in the Arabian Gulf region.
Показать больше [+] Меньше [-]First evidence of persistent organic contaminants as potential anthropogenic stressors in the Barndoor Skate Dipturus laevis Полный текст
2017
Lyons, Kady | Adams, Douglas H.
Although exploited populations of elasmobranchs may be able to recover from fishing pressure, there is little information regarding the Barndoor Skate's ability to cope with other anthropogenic stressors such as organic contaminants (OCs). Legacy OCs were measured in liver, muscle and ova from fourteen Barndoor Skates with mature skates having significantly greater mean concentrations of OCs than immature skates, demonstrating bioaccumulation with age. Using Toxic Equivalency Factors, skates were found to have levels of PCBs that have been shown to elicit negative physiological responses in other fishes and these results highlight the need for future studies to investigate the potential impacts that bioaccumulated organic contaminants have on the recovery and conservation of this vulnerable species.
Показать больше [+] Меньше [-]Risk assessment of trace metal-polluted coastal sediments on Hainan Island: A full-scale set of 474 geographical locations covering the entire island Полный текст
2017
Li, Feng | Lin, Ze-Feng | Wen, Jia-Sheng | Wei, Yan-Sha | Gan, Hua-Yang | He, Hai-Jun | Lin, Jin-Qin | Xia, Zhen | Chen, Bi-Shuang | Guo, Wen-Jie | Tan, Cha-Sheng | Cai, Hua-Yang
Hainan Island is the second largest island and one of the most famous tourist destinations in China, but sediment contamination by trace metals in coastal areas is a major issue. However, full-scale risk assessments of trace metal-polluted coastal sediments are lacking. In this study, coastal surface sediments from 474 geographical locations covering almost the entire island were collected to identify risk-related variables. Controlling factors and possible sources of trace metals were identified, and the toxicity effects were carefully evaluated. Our results suggest that trace-metal pollution in coastal sediments, which was mainly caused by Pb, Zn and Cu emissions, has primarily resulted from industrial sewage and shipping activities and has threatened the offshore ecosystem of Hainan Island and warrants extensive consideration. This is the first study that has systematically investigated trace metal-polluted coastal sediments throughout the entirety of Hainan Island and provides solid evidence for sustainable marine management in the region.
Показать больше [+] Меньше [-]The toxic exposure of flamingos to per- and Polyfluoroalkyl substances (PFAS) from firefighting foam applications in Bonaire Полный текст
2017
de Vries, Pepijn | Slijkerman, Diana M.E. | Kwadijk, Christiaan J.A.F. | Kotterman, Michiel J.J. | Posthuma, Leo | de Zwart, Dick | Murk, Albertinka J. | Foekema, Edwin M.
In 2010 an oil terminal next to nature reservation Saliña Goto (Bonaire) caught fire. Firefighting resulted in elevated per- and polyfluoroalkyl substances (PFAS) concentrations in the salt lake. Within months flamingo abundance in Goto dropped to near complete absence. After statistical analysis, rainfall was deemed an unlikely cause for this decline. Toxicological effects on abundance of prey are likely the main cause for the flamingo absence. This reduced PFAS exposure via food and thus risk towards flamingos during the first years after the fires. Although the sediment is still polluted with persistent PFAS, flamingos returned, and started to feed on organisms with PFAS levels that exceed safety thresholds, placing the birds and other wildlife at risk. Monitoring bird populations is advised to assess potential toxic effects on birds and their offspring. This case suggests that applying persistent chemicals to reduce incident impacts may be more harmful than the incident itself.
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