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A critical assessment of visual identification of marine microplastic using Raman spectroscopy for analysis improvement
2015
Lenz, Robin | Enders, Kristina | Stedmon, Colin A. | Mackenzie, David M.A. | Nielsen, Torkel Gissel
Identification and characterisation of microplastic (MP) is a necessary step to evaluate their concentrations, chemical composition and interactions with biota. MP ≥10μm diameter filtered from below the sea surface in the European and subtropical North Atlantic were simultaneously identified by visual microscopy and Raman micro-spectroscopy. Visually identified particles below 100μm had a significantly lower percentage confirmed by Raman than larger ones indicating that visual identification alone is inappropriate for studies on small microplastics. Sixty-eight percent of visually counted MP (n=1279) were spectroscopically confirmed being plastic. The percentage varied with type, colour and size of the MP. Fibres had a higher success rate (75%) than particles (64%). We tested Raman micro-spectroscopy applicability for MP identification with respect to varying chemical composition (additives), degradation state and organic matter coating. Partially UV-degraded post-consumer plastics provided identifiable Raman spectra for polymers most common among marine MP, i.e. polyethylene and polypropylene.
Afficher plus [+] Moins [-]Persistent organic pesticide residues in sediments of Vasai Creek near Mumbai: Assessment of sources and potential ecological risk
2015
Singare, Pravin U.
Thirteen persistent organic pesticides were investigated in the sediments of Vasai Creek near Mumbai to evaluate their pollution levels and potential risks. It was observed that ΣOCPs level was in the range of 597–1538ng/g dw, with an average value of 1115.25ng/g dw. The level of ΣOPPs was in the range of 492–1034ng/g dw, with an average value of 798.15ng/g dw. The values o,p′-DDT/p,p′-DDT ratio gives an indication of use of technical DDT as the prime source of DDT, while the α/γ-BHC ratio indicate that BHCs in study area might have been received from fresh lindane. The results of an ecological risk assessment showed that sediment bound organic pesticides are of more ecotoxicological concern as they might create adverse ecological risk to the marine breeding habitats. These pesticides residues may get remobilize and released to overlying waters creating adverse effects on terrestrial and aquatic organisms.
Afficher plus [+] Moins [-]Impact of deep-water fish farms on benthic macrofauna communities under different hydrodynamic conditions
2015
Valdemarsen, Thomas | Hansen, Pia Kupka | Ervik, Arne | Bannister, Raymond J.
In this study the environmental impacts of two fish farms located over deep water (180–190m) were compared. MC-Farm was located at a site with slightly higher water currents (mean current speed 3–5cms−1) than LC-farm (<2cms−1). Macrofauna composition, bioirrigation and benthic fluxes (CO2 and NH4+) were quantified at different stages of the production cycle, revealing very different impact of the two farms. Macrofauna abundance and bioirrigation were stimulated compared to a non-impacted reference site at MC-farm, while macrofauna diversity was only moderately reduced. In contrast, macrofauna communities and related parameters were severely impoverished at LC-Farm. This study suggests that deep-water fish farms should not be sited in low current areas (<2cms−1), since this will hamper waste dispersal and aggravate environmental impacts. On the other hand, fish farming at slightly more dynamic sites can lead to stimulated benthic macrofauna communities and only moderate environmental impacts.
Afficher plus [+] Moins [-]Baseline hydrocarbon levels in New Zealand coastal and marine avifauna
2015
McConnell, H.M. | Gartrell, B.D. | Chilvers, B.L. | Finlayson, S.T. | Bridgen, P.C.E. | Morgan, K.J.
The external effects of oil on wildlife can be obvious and acute. Internal effects are more difficult to detect and can occur without any external signs. To quantify internal effects from oil ingestion by wildlife during an oil spill, baseline levels of ubiquitous hydrocarbon fractions, like polycyclic aromatic hydrocarbons (PAHs), need to be established. With these baseline values the extent of impact from exposure during a spill can be determined. This research represents the first investigation of baseline levels for 22 PAHs in New Zealand coastal and marine avian wildlife. Eighty-five liver samples were tested from 18 species. PAHs were identified in 98% of livers sampled with concentrations ranging from 0 to 1341.6ng/g lipid wt or on wet wt basis, 0 to 29.5ng/g. Overall, concentrations were low relative to other globally reported avian values. PAH concentration variability was linked with species foraging habitat and migratory patterns.
Afficher plus [+] Moins [-]Water protection in the Baltic Sea and the Chesapeake Bay: Institutions, policies and efficiency
2015
Iho, Antti | Ribaudo, Marc | Hyytiäinen, Kari
The Baltic Sea and the Chesapeake Bay share many characteristics. Both are shallow, brackish marine areas that suffer from eutrophication. Successful policies targeting point source pollution have lowered nutrient loads in both areas, but achieving the desired marine quality will require further abatement: efforts may be extended to more complicated and expensive pollution sources, notably agricultural nonpoint loads. Despite their ecological similarities, the two watersheds have different histories and institutional settings and have thus adopted different policies. Comparing and contrasting the policies reveal ways to improve the efficiency of each and ways to avoid the path of trial and error. No comparison of the parallel protection efforts, which involve expenditures of hundreds of millions of dollars annually, has been carried out to date. The present paper analyzes the policies applied in the two regions, distilling the results into six recommendations for future steps in preserving what are valuable sea areas.
Afficher plus [+] Moins [-]Fire Influences on Atmospheric Composition, Air Quality and Climate
2015
Voulgarakis, Apostolos | Field, Robert D.
Fires impact atmospheric composition through their emissions, which range from long-lived gases to short-lived gases and aerosols. Effects are typically larger in the tropics and boreal regions but can also be substantial in highly populated areas in the northern mid-latitudes. In all regions, fire can impact air quality and health. Similarly, its effect on large-scale atmospheric processes, including regional and global atmospheric chemistry and climate forcing, can be substantial, but this remains largely unexplored. The impacts are primarily realised in the boundary layer and lower free troposphere but can also be noticeable in upper troposphere/lower stratosphere (UT/LS) region, for the most intense fires. In this review, we summarise the recent literature on findings related to fire impact on atmospheric composition, air quality and climate. We explore both observational and modelling approaches and present information on key regions and on the globe as a whole. We also discuss the current and future directions in this area of research, focusing on the major advances in emission estimates, the emerging efforts to include fire as a component in Earth system modelling and the use of modelling to assess health impacts of fire emissions.
Afficher plus [+] Moins [-]Microwave assisted catalytic removal of elemental mercury from flue gas using Mn/zeolite catalyst
2015
Wei, Zaishan | Luo, Yuwei | Li, Baoren | Cheng, Zhouyang | Wang, Jianbin | Ye, Qihong
The integrated microwave with Mn/zeolite and ozone (MCO) and combined microwave with Mn/zeolite (MC) was employed to oxidize elemental mercury (Hg0) in simulated flue gas. The results show that mercury removal efficiency attained 35.3% in the MC, over 92% of Hg0 removal efficiency could be obtained in the MCO. The optimal microwave power and empty bed residence time (EBRT) in the microwave plasma catalytic oxidation were 264 W and 0.41 s, respectively. The effect of Hg0 oxidation in the MCO was much higher than that in the MC. Microwave accentuated catalytic oxidation of mercury, and increased mercury removal efficiency. The additional use of ozone to the microwave–catalysis over Mn/zeolite led to the enhancement of mercury oxidation. Mn/zeolite catalyst was characterized by X–ray diffraction (XRD), X–ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FT–IR), scanning electron microscopy (SEM) and the Brunauer Emmett Teller (BET) method. Microwave catalytic mercury over Mn/zeolite was dominated by a free radical oxidation route. Ozone molecules in air could enhance free radical formation. The coupling role between ozone and radicals on mercury oxidation in the MCO was formed. The MCO appears to be a promising method for emission control of elemental mercury.
Afficher plus [+] Moins [-]Chemical compositions and source identification of particulate matter (PM2.5 and PM2.5–10) from a scrap iron and steel smelting industry along the Ife–Ibadan highway, Nigeria
2015
Owoade, Kayode O. | Hopke, Philip K. | Olise, Felix S. | Ogundele, Lasun T. | Fawole, Olusegun G. | Olaniyi, Bamidele H. | Jegede, Olugbemiga O. | Ayoola, Muritala A. | Bashiru, Muniru I.
To determine the chemical compositions and source identification of PM2.5 and PM2.5–10 fractions, airborne particulate matter (PM) samples were collected from May, 2011 through April, 2012 at three sites: up and downwind and within a scrap iron and steel smelting industry, Ife–Ibadan highway, south western Nigeria. Samples of PM2.5 (fine) and PM2.5–10 (coarse) were collected on Nuclepore polycarbonate filters using a low volume GENT sampler equipped with a stacked filter unit (SFU). A total of 200 samples were collected (100 of each fraction). The mass concentration of the sampled fine and coarse PM fraction ranged between 14.4–986.5μg/m3 and 11.2–3 250μg/m3, respectively. These values exceed the permissible daily limit (NAAQS) of 35μg/m3 for PM2.5 and 150μg/m3 for PM10. The samples were analyzed for black carbon (BC) using an optical transmissometer and for elemental concentrations using X–Ray Fluorescence (XRF). The size–resolved data sets were analyzed using Positive Matrix Factorization (PMF) to identify possible sources and estimate the contribution of these sources to the fine and coarse PM mass concentrations. Four source categories, providing stable profiles, were identified for both fine and coarse fractions. The identified sources and their contributions for the fine fraction are coking coal (83%), soil (10%), metallurgical industry (6%), and electronic waste processing (1%). For the coarse fraction, the identified sources are metallurgical production plus electronic waste (53%), suspended input materials (28%), soil (18%), and galvanized steel scrap with cadmium (1%). Conditional probability function (CPF) identified the local sources for both the fine and coarse PM samples. This work presents the first known major use of PMF in Nigeria for source identification in particulate matter (PM) studies.
Afficher plus [+] Moins [-]Biotope map of the German Baltic Sea
2015
Schiele, Kerstin S. | Därr, Alexander | Zettler, Michael L. | Friedland, René | Tauber, Franz | von Weber, Mario | Voss, Joachim
Full-coverage maps on the distribution of marine biotopes are a necessary basis for Nature Conservation and Marine Spatial Planning. Yet biotope maps do not exist in many regions. We are generating the first full-coverage biotope map for the German Baltic Sea according to the HELCOM Underwater biotope and habitat classification system (HUB). Species distribution modelling is applied to create full-coverage spatial information of biological features. The results of biomass modelling of twelve target taxa and presence/absence modelling of three target taxa enabled the identification of biological levels up to HUB level 6. Environmental data on bathymetry, light penetration depth and substrate are used to identify habitat levels. HUB biotope levels were combined with HUB habitat levels to create a biotope map. Altogether, 68 HUB biotopes are identified in the German Baltic Sea. The new biotope map combining substrate characteristics and biological communities will facilitate marine management in the area.
Afficher plus [+] Moins [-]Ecophysiological responses of three Mediterranean invasive seaweeds (Acrothamnion preissii, Lophocladia lallemandii and Caulerpa cylindracea) to experimental warming
2015
Samperio-Ramos, Guillermo | Olsen, Ylva S. | Tomas, Fiona | Marbà, Núria
The Mediterranean Sea is a hotspot for invasive species and projected Mediterranean warming might affect their future spreading. We experimentally examined ecophysiological responses to the temperature range 23–31°C in three invasive seaweeds commonly found in the Mediterranean: Acrothamnion preissii, Caulerpa cylindracea and Lophocladia lallemandii. The warming range tested encompassed current and projected (for the end of 21st Century) maximum temperatures for the Mediterranean Sea. Optimal ecophysiological temperatures for A. preissii, C. cylindracea and L. lallemandii were 25°C, 27°C and 29°C, respectively. Warming below the optimal temperatures enhanced RGR of all studied invasive seaweeds. Although sensitive, seaweed photosynthetic yield was less temperature-dependent than growth. Our results demonstrate that temperature is a key environmental parameter in regulating the ecophysiological performance of these invasive seaweeds and that Mediterranean warming conditions may affect their invasion trajectory.
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