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Modeling marine oily wastewater treatment by a probabilistic agent-based approach Full text
2018
Jing, Liang | Chen, Bing | Zhang, Baiyu | Ye, Xudong
This study developed a novel probabilistic agent-based approach for modeling of marine oily wastewater treatment processes. It begins first by constructing a probability-based agent simulation model, followed by a global sensitivity analysis and a genetic algorithm-based calibration. The proposed modeling approach was tested through a case study of the removal of naphthalene from marine oily wastewater using UV irradiation. The removal of naphthalene was described by an agent-based simulation model using 8 types of agents and 11 reactions. Each reaction was governed by a probability parameter to determine its occurrence. The modeling results showed that the root mean square errors between modeled and observed removal rates were 8.73 and 11.03% for calibration and validation runs, respectively. Reaction competition was analyzed by comparing agent-based reaction probabilities, while agents' heterogeneity was visualized by plotting their real-time spatial distribution, showing a strong potential for reactor design and process optimization.
Show more [+] Less [-]Similarities and differences of 137Cs distributions in the marine environments of the Baltic and Black seas and off the Fukushima Dai-ichi nuclear power plant in model assessments Full text
2018
Maderich, V. | Bezhenar, R. | Tateda, Y. | Aoyama, M. | Tsumune, D.
The compartment model POSEIDON-R with an embedded food web model was used to assess 137Cs distributions in the Baltic and Black seas and off the Pacific coast of Japan during 1945–2020 due to the weapon testing and accidents at the Chernobyl and Fukushima Dai-ichi nuclear power plants. The results of simulations conducted with generic parameters agreed well with measurements of 137Cs concentrations in the water, bottom sediments, and in fish. In the Black and Baltic seas, salinity variations affected the transfer of 137Cs through the food web. The contamination of pelagic fish followed the water contamination with some delay, whereas demersal fish depuration was found to be related to decreasing 137Cs concentrations in the upper sediment layer. On the Pacific shelf off Japan, intensive currents and eddies caused the simulated depuration rates in fish to be one-two orders of magnitude larger than those in the semi-enclosed Black and Baltic seas.
Show more [+] Less [-]Using best expert judgement to harmonise marine environmental status assessment and maritime spatial planning Full text
2018
Elliott, Michael | Boyes, Suzanne J. | Barnard, Stephen | Borja, Angel
All maritime states have the challenge of maintaining the environmental quality of their seas while at the same time maximising their economic potential thus requiring appropriate science, governance and management measures. In Europe, directives and regulations are used to address the pressures affecting the health and sustainability of marine resources, and to promote Good Environmental Status (GES) (e.g. the Marine Strategy Framework Directive, MSFD), while having a coherent and integrated pattern of sea use (e.g. the Maritime Spatial Planning Directive, MSPD). Therefore, an approach is required to meet these challenges for all maritime states including, for Europe, the joint adoption of these two directives. As such an approach does not yet exist, one is proposed here based on a hypothetical example and a Best Expert Judgement (BEJ) methodology. Forty-two marine science, management and impact assessment specialists provided views on a hypothetical marine scenario to derive and interrogate a framework applicable to marine areas with multiple uses and users. The scenario allowed the severity of the activity effects-footprints to be determined on the 11 MSFD Descriptors of GES with that severity being weighted according to the area of each activity effect-footprint. In turn, this allowed the calculation of marine regional environmental status thereby indicating whether the adoption of quality assessment and spatial planning can be mutually beneficial, or are antagonistic in meeting environmental targets. This paper uses the proposed approach to discuss maximising the assimilative capacity of a marine area and minimising the environmental degradation due to new activities. It especially shows the role of BEJ in cases where marine adaptive management is still required despite their being an often paucity of information or data on which to base management decisions.
Show more [+] Less [-]Distribution and enrichment of trace metals in surface marine sediments collected by the manned submersible Jiaolong in the Yap Trench, northwest Pacific Ocean Full text
2018
Yang, Jichao | Cui, Zhen | Dada, Olusegun A. | Yang, Yaomin | Yu, Hongjun | Xu, Yue | Lin, Zhen | Chen, Yu | Tang, Xin
In this study, we carried out grain size and heavy metal analyses and also assessed heavy metal enrichment and ecological risk indices in ten sediment samples collected by the manned submersible Jiaolong at different segments of the Yap Trench. The results showed that the sediments in the Yap Trench were mainly slumping deposits composed of sandy silt. Heavy metals in the sediments showed different spatial distribution patterns from north to south direction of the trench. The distribution pattern of these heavy metals also differed in the eastern and western flanks of the trench. From the results of the enrichment factors, only arsenic, chromium, and manganese showed a slight enrichment. However, all elements were affected by natural factors. Further, most elements showed a low ecological risk, and only arsenic showed a moderate risk at two stations. Finally, the potential ecological risk of the whole study area was at a low level.
Show more [+] Less [-]Mapping widespread and increasing underwater noise pollution from acoustic deterrent devices Full text
2018
Findlay, C.R. | Ripple, H.D. | Coomber, F. | Froud, K. | Harries, O. | van Geel, N.C.F. | Calderan, S.V. | Benjamins, S. | Risch, D. | Wilson, B.
Acoustic deterrent devices (ADDs) are used in attempts to mitigate pinniped depredation on aquaculture sites through the emission of loud and pervasive noise. This study quantified spatio-temporal changes in underwater ADD noise detections along western Scotland over 11 years. Acoustic point data (‘listening events’) collected during cetacean line-transect surveys were used to map ADD presence between 2006 and 2016. A total of 19,601 listening events occurred along the Scottish west coast, and ADD presence was recorded during 1371 listening events. Results indicated a steady increase in ADD detections from 2006 (0.05%) to 2016 (6.8%), with the highest number of detections in 2013 (12.6%), as well as substantial geographic expansion. This study demonstrates that ADDs are a significant and chronic source of underwater noise on the Scottish west coast with potential adverse impacts on target (pinniped) and non-target (e.g. cetaceans) species, which requires further study and improved monitoring and regulatory strategies.
Show more [+] Less [-]Effects of temperature and salinity on Ruppia sinensis seed germination, seedling establishment, and seedling growth Full text
2018
Gu, Ruiting | Zhou, Yi | Song, Xiaoyue | Xu, Shaochun | Zhang, Xiaomei | Lin, Haiying | Xu, Shuai | Zhu, Shuyu
As typical submerged aquatic vegetation, Ruppia species are facing population reductions due to anthropogenic impacts. In this study, we investigated the effects of temperature and salinity on seed germination and seedling establishment of Ruppia sinensis seeds collected from northern China. The effects of seven salinities (0–50) and six water temperatures (0–30°C) on seed germination were investigated to identify the environmental conditions that could potentially limit survival and growth. We found that: 1) optimum seed germination was salinity 5 at 30°C; 2) high salinity (salinity 40–50) and low temperature (0°C) significantly inhibited seed germination; 3) seed germination with increasing temperature showed a bimodal pattern at suitable salinities (5–10); 4) storing seeds at high salinities (40–50) or low temperature (0°C) promoted germination after transferal to optimal germination conditions. These findings may serve as useful information for R. sinensis habitat establishment and restoration programs.
Show more [+] Less [-]Radioactive cesium concentrations in coastal suspended matter after the Fukushima nuclear accident Full text
2018
Kubo, Atsushi | Tanabe, Kai | Suzuki, Genta | Itō, Yukari | Ishimaru, Takashi | Kasamatsu-Takasawa, Nobue | Tsumune, Daisuke | Mizuno, Takuji | Watanabe, Yutaka W. | Arakawa, Hisayuki | Kanda, Jota
Radioactive cesium concentrations in the suspended matter of the coastal waters around the Fukushima Daiichi Nuclear Power Plant (FDNPP) were investigated between January 2014 and August 2015. The concentrations of radioactive cesium in the suspended matter were two orders higher in magnitude than those determined in the sediment. In addition, we discovered highly radioactive Cs particles in the suspended matter using autoradiography. The geometrical average radioactivity of particles was estimated to be 0.6 Bq at maximum and 0.2 Bq on average. The contribution ratio of highly radioactive Cs particles to each sample ranged from 13 to 54%, and was 36% on average. A major part of the radioactive Cs concentration in the suspended matter around the FDNPP was strongly influenced by the highly radioactive particles. The subsequent resuspension of highly radioactive Cs particles has been suggested as a possible reason for the delay in radioactive Cs depuration from benthic biota.
Show more [+] Less [-]Assessing the effectiveness of surrogates for species over time: Evidence from decadal monitoring of a Mediterranean transitional water ecosystem Full text
2018
Bevilacqua, S. | Mistri, M. | Terlizzi, A. | Munari, C.
The use of higher taxa or alternative approach to species surrogacy, such as the BestAgg procedure, could represent cost-effective solutions to avoid expensive species-level identifications in monitoring activities, especially on the long term. However, whether a set of surrogates would be effective in subsequent reiteration of the same assessment remains largely unsolved. We used a long-term dataset on macro-benthic assemblages to test the hypothesis that family-level and BestAgg surrogates which are effective for a limited period of monitoring could be successfully applied to quantify community patterns also in subsequent monitoring programmes. The effectiveness of surrogates in detecting temporal variations in assemblage structure as at species level remained basically unaffected over a decade. Recognizing once and for all if species surrogacy may have a practical value for monitoring will strongly depend on future assessments of the potential of surrogates to reflect community changes and to retain this prerogative over time.
Show more [+] Less [-]Modeling atmospheric volatile organic compound concentrations resulting from a deepwater oil well blowout – Mitigation by subsea dispersant injection Full text
2018
Crowley, Deborah | French-McCay, Deborah | Santos, L. (Lynne) | Chowdhury, Biswanath | Markussen, Robin
The atmospheric concentrations of volatile organic compounds (VOCs) generated by surface slicks during an oil spill have not been extensively studied. We modeled oil transport and fate, air emissions, and atmospheric dispersion of VOCs from a hypothetical deepwater well blowout in De Soto Canyon of the Gulf of Mexico assuming no intervention and use of SubSea Dispersant Injection (SSDI) at the source during three week-long periods representing different atmospheric mixing conditions. Spatially varying time histories of atmospheric VOCs within ~2 km from the release site were estimated. As compared to the no-intervention case, SSDI dispersed the discharged oil over a larger water volume at depth and enhanced VOC dissolution and biodegradation, thereby reducing both the total mass of VOCs released to the atmosphere and the concentration of VOCs within 2 km from the release site. Atmospheric conditions also influenced the VOC concentrations, although to a lesser degree than SSDI.
Show more [+] Less [-]Taiwan's legal framework for marine pollution control and responses to marine oil spills and its implementation on T.S. Taipei cargo shipwreck salvage Full text
2018
Fan, Chihhao | Hsu, Cheng-Jui | Lin, Jia-Yu | Kuan, Yung-Kai | Yang, Chieh-Chung | Liu, Ruixiang | Yeh, Jiunn-Horng
Many shipwreck events occur in the neighboring areas of Taiwan due to the volume of maritime traffic and geographical conditions around Taiwan. The oil spills from such events can be devastating for the surrounding sea and coastal areas. The government realized the importance of marine pollution prevention and enforced the Marine Pollution Control Act and the Major Marine Oil Pollution Emergency Response Plan to mitigate the impact of oil spill pollution. The T.S. Taipei shipwreck highlighted the effectiveness of the national marine pollution prevention system. Inter-departmental cooperation and collaboration with private sectors are the keys for effective response. This article is the first detailed documentation of an oil spill response for a maritime incident from the beginning to the final termination of shipwreck removal. It shows the people in Taiwan intend to collaborate with other states to make a significant contribution to marine environment conservation and sustainability.
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