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Результаты 2541-2550 из 8,010
Fungi and biochar applications in bioremediation of organic micropollutants from aquatic media Полный текст
2021
Madadi, Rozita | Bester, Kai
The conventional wastewater treatment system such as bacteria, is not able to remove recalcitrant micropollutants effectively. While, fungi have shown high capacity in degradation of recalcitrant compounds. Biochar, on the other hand, has gained attention in water and wastewater treatment as a low cost and sustainable adsorbent. This paper aims to review the recent applications of three major fungal divisions including Basidiomycota, Ascomycota, and Mucoromycotina, in organic micropollutants removal from wastewater. Moreover, it presents an insight into fungal bioreactors, fungal biofilm and immobilization system. Biochar adsorption capacities for organic micropollutants removal under different operating conditions are summarized. Finally, few recommendations for further research are established in the context of the combination of fungal biofilm with the technologies relying on the adsorption by porous carbonaceous materials.
Показать больше [+] Меньше [-]Bacterial community responses to the redox profile changes of mariculture sediment Полный текст
2021
Shi, Rongjun | Han, Tingting | Xu, Shumin | Huang, Honghui | Qi, Zhanhui | Zhu, Qingzhi
Suspended mariculture has significantly influences on the benthic sediment. However, our understanding on how bacterial communities respond to mariculture induced changes in redox profiles is limited. In present study, sediments from two maricultures and reference areas were collected and incubated for 28 day. The results indicated that the dominant pathway of organic matter mineralization in the sediment varied from groups, in the reference, it was the iron reduction, but in the two mariculture groups it was the SO₄²⁻ reduction. Remarkable changes of bacteria community were recorded in the aerobic zone, where the abundances of 14 OTUs belonging to Gammaproteobacteria and Alphaproteobacteria were significantly higher than that in oxidation and anaerobic zones. However, 4 keystone OTUs were strictly anaerobic and belonging to Desulfobacteraceae (n = 3) and Marinilabiaceae (n = 1). The main environmental drivers determining sediment bacterial distribution were the particle organic carbon, dissolve oxygen, NO₃⁻, and moisture content.
Показать больше [+] Меньше [-]Protection outcomes for fish trophic groups across a range of management regimes Полный текст
2021
Osuka, Kennedy E. | Stewart, Bryce D. | Samoilys, Melita A. | Roche, Ronan C. | Turner, John | McClean, Colin
Understanding how Marine Protected Areas (MPAs) improve conservation outcomes across anthropogenic pressures can improve the benefits derived from them. Effects of protection for coral reefs in the western and central Indian Ocean were assessed using size-spectra analysis of fish and the relationships of trophic group biomass with human population density. Length-spectra relationships quantifying the relative abundance of small and large fish (slope) and overall productivity of the system (intercept) showed inconsistent patterns with MPA protection. The results suggest that both the slopes and intercepts were significantly higher in highly and well-protected MPAs. This indicates that effective MPAs are more productive and support higher abundances of smaller fish, relative to moderately protected MPAs. Trophic group biomass spanning piscivores and herbivores, decreased with increasing human density implying restoration of fish functional structure is needed. This would require addressing fisher needs and supporting effective MPA management to secure ecosystem benefits for coastal communities.
Показать больше [+] Меньше [-]Hypoxia in the Persian Gulf and the Strait of Hormuz Полный текст
2021
Saleh, Abolfazl | Abtahi, Behrooz | Mirzaei, Nikoo | Chen, Chen-Tung Arthur | Ershadifar, Hamid | Ghaemi, Maryam | Hamzehpour, Ali | Abedi, Ehsan
In this article dissolved oxygen results of research cruises through the Persian Gulf during 2018–2019 are discussed. The results showed that summer to autumn hypoxia occurred mainly at depths ≥ 50 m to the bottom. This seasonal hypoxia started in late summer reaching its greatest severity in mid-autumn with an area of 50,000 km² in the Persian Gulf. The minimum oxygen measured at the near-bottom layer of the western basin in autumn (25.8 μmol/kg) was lower than any previous measurement in the open waters of the Persian Gulf. In the Strait of Hormuz, the seasonal hypoxia appeared in summer in the near bottom of the most eastern part at the Iranian side. pHT values recorded in hypoxic waters were as low as what is predicted for surface ocean under ocean acidification in 2100. Considering the results, we suggest evaluating the effects of hypoxia and acidification on the Persian Gulf ecosystems.
Показать больше [+] Меньше [-]Seasonal dynamics of polycyclic aromatic hydrocarbons between water and sediment in a tide-dominated estuary and ecological risks for estuary management Полный текст
2021
Niu, Lixia | Luo, Xiangxin | Cai, Huayang | Liu, Feng | Zhang, Tao | Yang, Qingshu
Understanding the transportation of polycyclic aromatic hydrocarbons (PAHs) across the water-sediment interface can help researchers to partition their sources while being particularly important for managing PAH input. This study fully explored the PAH dynamics between water and sediment in a tide-dominated estuary. The monthly concentration of ΣPAHs in sediments ranged from 325.47 to 1098.49 ng/g (dry weight), while that in water varied from 154.00 to 725.80 ng/L. The PAH levels found in the present study were relatively high in comparison with other estuarine systems worldwide. The high-molecular-weight PAHs were more readily redissolved from sediment to water, while the low-molecular-weight PAHs were mostly in an unsaturated state with diffusion occurring from water to sediment. The seasonal differences of ΣPAHs were significant and were largely controlled by the changes in sediment properties, marine currents, and water temperature. The diagnostic ratios revealed that predominant sources of PAHs were pyrogenic processes and petrogenic inputs.
Показать больше [+] Меньше [-]Stochastic oil spill modeling for environmental protection at the Port of Taranto (southern Italy) Полный текст
2021
Liubartseva, S. | Federico, I. | Coppini, G. | Lecci, R.
We performed stochastic simulations of hypothetical oil spills from a single-point buoy mooring and subsea pipeline for the Port of Taranto given that this port is an essential strategic hub in the European logistic chain. Our methodology integrates (1) the MEDSLIK-II oil spill model coupled to a high-resolution hydrodynamic model run on an unstructured grid in operational forecasting mode; (2) a hypothetical oil spill scenario based on a historical pipeline rupture at the Port of Genoa, 2016; and (3) randomly sampling the environmental conditions over 2018–2020. The main oil drift was found to be directed southwesterly towards the outlet to the open sea. When oil is transported by highly variable currents, waves and turbulent mixing, it is exposed to multiple strandings and washing-offs from concrete constructions in the port. Consequently, oil tends to be dispersed almost isotropically over the Mar Grande, indicating low to moderate pollution indices.
Показать больше [+] Меньше [-]Horizontal variation of microplastics with tidal fluctuation in the Chao Phraya River Estuary, Thailand Полный текст
2021
Oo, Phyo Zaw | Boontanon, Suwanna Kitpati | Boontanon, Narin | Tanaka, Shuhei | Fujii, Shigeo
Microplastic (MP) pollution in estuarine environments is poorly characterized globally, although they are extensive buffer regions between terrestrial, freshwater and seawater environments. This research aims to investigate MP pollution levels and variations of MPs abundance with tidal fluctuation. Fourteen samples were collected from the surface water of the Chao Phraya River Estuary, Thailand using the Manta net at flood and ebb tides. The average abundance of microplastics at flood tide was 5.16 × 10⁵ particles/km² and at ebb tide was 3.11 × 10⁵ particles/km². The abundance of microplastics in the estuary was directly related to the tidal fluctuation, creating an accumulation of microplastics in the study area. Polypropylene, polyethylene, and polystyrene were the most common polymers. The findings provide important information on the pollution status of microplastics in the Chao Phraya River Estuary and the variation of suspended microplastics with tidal fluctuation should be considered in future estuarine microplastic studies.
Показать больше [+] Меньше [-]Quantitative estimation of sea surface temperature increases resulting from the thermal discharge of coastal power plants in China Полный текст
2021
Lin, Jie | Zou, Xinqing | Huang, Faming | Yao, Yulong
The operation of coastal nuclear power plants and thermal power plants (CNATPPs) can cause regional sea surface temperature (SST) increases. To assess their effects on coastal ecosystems, the scope and extent of their impacts must be understood. We aimed to quantitatively assess the SST increases caused by thermal discharge under climate warming by comparing SSTs between control and test groups and among different offshore buffer zones based on daily MODIS SST data from 2002 to 2017. The results showed that (1) a good correlation occurred between the CNATPP installed capacity and SST increase in the 0–2 km offshore waters; (2) the SST increase caused by thermal discharge was the largest in summer and the smallest in winter; and (3) the effect of thermal discharge occurred within 2 km offshore when the installed capacity exceeded 2000 MW and extended to 5 km when it reaches more than 4000 MW.
Показать больше [+] Меньше [-]Antibiotic resistance of culturable heterotrophic bacteria isolated from shrimp (Penaeus vannamei) aquaculture ponds Полный текст
2021
Nadella, Ranjit Kumar | Panda, Satyen Kumar | Madhusudana Rao, B. | Pani Prasad, K. | Raman, R.P. | Mothadaka, Mukteswar Prasad
Shrimp aquaculture is one of the fastest growing food-producing avenues, where antibiotics usage has become an issue of great concern due to the development of antimicrobial resistance in bacteria. A total of 2304 bacterial isolates from 192 samples (sediment, water, shrimp, and source water) from Andhra Pradesh, India were screened. Antibiotic resistance of bacterial isolates was highest for oxytetracycline (23.4%) followed by erythromycin (12.7%), co-trimoxazole (10%) ciprofloxacin (9.6%), and chloramphenicol (6%), of which 11.9% isolates were multi-drug resistant. Bacterial isolates from shrimp (26.7%), water (23.9%), and sediment (19.6%) samples exhibited more resistance (p ≤ 0.05) towards oxytetracycline. Higher antibacterial resistance was observed from samples of southern Andhra Pradesh (locations L6 and L7). Gram negative bacteria were more prevalent (64%) and showed significantly (p ≤ 0.01) higher resistance. This study indicated the wider distribution of antibiotic-resistant bacteria in shrimp aquaculture ponds with potential risk to humans and the environment.
Показать больше [+] Меньше [-]Integration of multi criteria decision analysis and GIS for evaluating the site suitability for aquaculture in southern coastal region, India Полный текст
2021
Shunmugapriya, K. | Panneerselvam, Balamurugan | Muniraj, Kirubakaran | Ravichandran, Nagavinothini | Prasath, P. | Thomas, Maciej | Duraisamy, Karunanidhi
Deterioration of water and soil quality, poor infrastructure facilities and improper maintenance are the major factors that govern aquaculture growth and production in major part of India. In the present study aims to identify the suitable land for aquaculture growth and suggest the sustainable practice to improvise the growth of aquaculture in study region. With use of analytical hierarchy process (AHP) the various significant parameters such as geology, pH, salinity, soil media, slope, geomorphology, land use land cover, distance to water, settlement and road networks were analyzed and based on these characteristics, thematic maps were prepared. The results are revealed that, that 882.13 km² area was most suitable, 1264.88 km² area was suitable and 14.00 km² area was unsuitable for aquaculture in the study region. The study results will helpful to decision makers and to make a design plan for aquaculture growth in the study region.
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