Interannual fluctuations in acoustic biomass estimates and in landings of small pelagic fish populations in relation to hydrology in the Strait of Sicily

The main results of research work carried out since 1998 with regard to the application of hydro-acoustic technologies for the evaluation of biomass and distribution of small pelagic fish species off the southern coast of Sicily are presented, taking into account information from hydrology and from ecology of the fish populations targeted. The biomass estimates and the population‐density charts presented concern the two main species, i.e. sardine Sardina pilchardus (Walbaum, 1792) and anchovy Engraulis encrasicolus (Linnaeus, 1758). Both the sardine and anchovy populations experienced large inter-annual fluctuations, with biomass estimates ranging from 6000 to over 36,000 tonnes (t) (sardine) and from about 7000 to 23,000 t (anchovy). Acoustic estimates are largely consistent with landings recorded in Sciacca (the main fishing port for small pelagic species in the study area) during the year following the evaluation surveys. In addition, trends in sardine and anchovy biomass estimates appears to be negatively correlated with the mean sea surface temperature calculated over the time intervals January–September (sardine) and June–November (anchovy) of the preceding year, which correspond to larval and juvenile growth periods of target species. Observed patterns would suggest the importance of enrichment processes relevant to the survival of early stages, so determining recruitment success and finally higher population sizes.     

Polychlorinated-dibenzo-p-dioxins, -dibenzofurans and -dioxin-like polychlorinated biphenyls in aquatic organisms from lake Kasumigaura,Japan

Polychlorinated-dibenzo-p-dioxins (PCDDs), -dibenzofurans (PCDFs) and -dioxin-like polychlorinated biphenyls (DLPCBs) were determined in aquatic wildlife of Kasumigaura Lake (KUL), Japan from 1978 to 2001. Two plankton species elucidated several fold greater concentrations (2400–7800) than small tiger fish (310–6500), shrimp (160–1100), and three large fish namely, black bass (120–240), carp (94–120) and mullet (54) on pg/g fat. PCDD homologues were predominant accumulants with >68–<95% contribution and remaining was shared by PCDFs. Accumulation, non-ortho DLPCBs in plankton (3500–9200), shrimp (1600–8600) and small fish (2000–8800) and large fish (1300–3900) on ng/g fat basis were several orders magnitude greater than PCDD/DFs. The mono-ortho DLPCBs in large fish species were 23?000–83?000?ng/g fat and which it is accounted 94.3–95.9% the total dioxin-like PCBs accumulation. Temporal trends of PCDDs, PCDFs, non-ortho PCBs and TEQ in shrimp and small tiger fish were varied. The mullet had minimum toxic equivalency “TEQ” (14?pg?TEQ/g) followed by plankton Neomysis intermedia (25?pg?TEQ/g), small tiger fish (mean: 33, ranges 14–66?pg?TEQ/g), plankton Cyclopus vicinus (34?pg?TEQ/g), carp (mean: 35, ranges 32–38?pg?TEQ/g), shrimp (mean: 38, ranges 11–68?pg?TEQ/g) and black bass (mean: 59, ranges 38–79?pg?TEQ/g) on fat basis. In all the samples, PCDD was predominant TEQ contributor followed by PCDFs and DLPCBs. The contribution of mono-ortho DLPCBs to the total TEQ was 0.52–0.92 in large fish.     

The temporal changes of the concentration level of typical toxic organics in the river sediments around Beijing

In this study, the current situation of five types of toxic organics and endocrine disrupters in the sediments of rivers around Beijing, i.e., polycyclic aromatic hydrocarbons (PAHs), phthalic acid esters (PAEs), organic chlorinated pesticides (OCPs), estrogens (Es), and bisphenol A (BPA), which included 56 contaminants, was analyzed and compared with that registered by the historical literatures. The ecological risks were also assessed. The total concentration of PAHs, PAEs, OCPs, Es, and BPA ranged from 232.5 ng·g^–1 to 5429.7 ng·g^–1, 2047.2 ng·g^–1 to 18051.5 ng·g^–1, 4.5 ng·g^–1 to 11.7 ng·g^–1, 18.1 ng·g^–1 to 105.2 ng·g^–1, and 36.3 ng·g^–1 to 69.6 ng·g^–1, respectively. Among these five types of organic compounds, the concentration levels of PAHs and OCPs have decreased significantly in the last ten years, while those of PAEs and Es had an upward trend compared with the previous studies. BPA still remained at a moderately high level, as it was ten years ago. The risks of the PAEs in all of the sample sites, and fluoranthene, benzo[a]anthrene, and benzo[a]pyrene in the Wenyu River sediment, were relatively high. These results supplemented the database of toxic organics’ concentration levels in the sediments of Beijing rivers.

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循环经济的国际发展趋势

从几个方面重点介绍了循环经济的国际发展趋势;把发展循环经济纳入法制化轨道;形成政府倡导、全民参与的意识和环境;大力促进循环经济产业化;鼓励技术创新,促进循环经济的发展。为我国发展循环经济,实现全面建设小康社会目标提供借鉴经验。     

广州主要工业源排放的气态污染物扩散模拟研究

以广州省控工业污染源排放的气态污染物(SO₂、NO_x为主要研究对象,通过中尺度气象模式MM5与空气质量模式CALPUFF耦合,模拟11月典型气象条件下, SO₂和NO_x的扩散传输过程,研究其时空分布特征,并分析省控工业污染源排放对特定区域(主要针对2010年亚运场馆)空气质量的影响。结果表明,主要受典型风速的影响,SO₂和NO_x浓度具有明显的时空分布不均匀性。浓度高峰值主要出现在晚间至凌晨时段,而浓度低峰值主要出现在白天至中午时段。受污染源分布、排放高度和风向的影响,荔湾区和越秀区污染物浓度较高,且在广州西南部形成较明显的污染带;且这些省控污染源对南沙体育馆空气质量有较大影响。 研究结果对广州空气污染来源分析具有一定参考意义。     

The Oxford Commission on Sustainable Consumption

The Oxford Commission on Sustainable Consumption aims to promote debate and action to achieve sustainable consumption. It has met four times since it was established in 1999. Commission members have undertaken a number of projects around the world, working with communities to explore pathways to more sustainable consumption. This paper summarises the Commission’s progress and the messages emerging from its work. Current consumption trends are supported by a number of social trends, including individualisation, the spread of the market ethos, urbanisation, globalisation, and the increasing awareness of risk and uncertainty. However, these trends contain the seeds of their own limitation. In particular, increasing discourse about ethics and social goals may be the key to a shift towards more sustainable consumption.     

Long-term variation of PM2.5 levels and composition at rural, urban, and roadside sites in Hong Kong: Increasing impact of regional air pollution

Long-term study of air pollution plays a decisive role in formulating and refining pollution control strategies. In this study, two 12-month measurements of PM_2.5 mass and speciation were conducted in 00/01 and 04/05 to determine long-term trend and spatial variations of PM_2.5 mass and chemical composition in Hong Kong. This study covered three sites with different land-use characteristics, namely roadside, urban, and rural environments. The highest annual average PM_2.5 concentration was observed at the roadside site (58.0±2.0 μg m⁻³ (average±2σ) in 00/01 and 53.0±2.7 μg m⁻³ in 04/05), followed by the urban site (33.9±2.5 μg m⁻³ in 00/01 and 39.0±2.0 μg m⁻³ in 04/05), and the rural site (23.7±1.9 μg m⁻³ in 00/01 and 28.4±2.4 μg m⁻³ in 04/05). The lowest PM_2.5 level measured at the rural site was still higher than the United States’ annual average National Ambient Air Quality Standard of 15 μg m⁻³. As expected, seasonal variations of PM_2.5 mass concentration at the three sites were similar: higher in autumn/winter and lower in summer. Comparing PM_2.5 data in 04/05 with those collected in 00/01, a reduction in PM_2.5 mass concentration at the roadside (8.7%) but an increase at the urban (15%) and rural (20%) sites were observed. The reduction of PM_2.5 at the roadside was attributed to the decrease of carbonaceous aerosols (organic carbon and elemental carbon) (>30%), indicating the effective control of motor vehicle emissions over the period. On the other hand, the sulfate concentration at the three sites was consistent regardless of different land-use characteristics in both studies. The lack of spatial variation of sulfate concentrations in PM_2.5 implied its origin of regional contribution. Moreover, over 36% growth in sulfate concentration was found from 00/01 to 04/05, suggesting a significant increase in regional sulfate pollution over the years. More quantitative techniques such as receptor models and chemical transport models are required to assess the temporal variations of source contributions to ambient PM_2.5 mass and chemical speciation in Hong Kong.     

Does the risk of encountering lions influence African herbivore behaviour at waterholes?

A central question in the study of predator–prey relationships is to what extent prey behaviour is determined by avoidance of predators. Here, we test whether the long-term risk of encountering lions and the presence of lions in the vicinity influence the behaviour of large African herbivores at waterholes through avoidance of high-risk areas, increases in group size, changes in temporal niche or changes in the time spent in waterhole areas. In Hwange National Park, Zimbabwe, we monitored waterholes to study the behaviour of nine herbivore species under different risks of encountering lions. We radio-collared 26 lions in the study area which provided the opportunity to monitor whether lions were present during observation sessions and to map longer-term seasonal landscapes of risk of encountering lions. Our results show that the preferred prey species for lions (buffalo, kudu and giraffe) avoided risky waterholes. Group size increased as encounter risk increased for only two species (wildebeest and zebra), but this effect was not strong. Interestingly, buffalo avoided the hours of the day which are dangerous when the long-term and short-term risks of encountering lions were high, and all species showed avoidance of waterhole use at night times when lions were in the vicinity. This illustrates well how prey can make temporal adjustments to avoid dangerous periods coinciding with predator hunting. Additionally, many herbivores spent more time accessing water to drink when the long- and short-term risks of encountering lions were high, and they showed longer potential drinking time when the long-term risk of encountering lions was high, suggesting higher levels of vigilance. This study illustrates the diversity of behavioural adjustments to the risk of encountering a predator and how prey respond differently to temporal variations in this risk.     

辽宁省土壤水分的时空变化格局分析

文章利用基于微波遥感的土壤水分产品评价辽宁省近40年(1979~2015)来干旱事件的时空变化特征。研究结果表明:辽宁省地表土壤水分呈现东高西低的空间分布;采用了一种具有时-频多分辨功能的小波分析(Wavelet Analysis)来更好地研究土壤水分时间序列变化规律,发现辽宁省年平均土壤水分随着时间具有波动降低趋势,并伴随有10年和20年左右的两个主要周期;从季节上看,四个季节的土壤水分时间序列变化十分剧烈,春夏两季土壤水分呈现出增加趋势,秋冬两季的土壤水分呈现出降低趋势。     

Annual nonmethane hydrocarbon trends in Beijing from 2000 to 2019

High loads of ground-level ozone have occurred with the implementation of the Air Pollution Prevention and Control Action Plan. However, the long temporal variation in precursor nonmethane hydrocarbons(NMHCs) has rarely been studied. In this study, we examined the evolution of NMHCs in Beijing based on ambient measurements from 2000 to 2019. The results indicated that the annual variation of ambient NMHCs during 2000 and 2019 could be divided into two stages. The mixing ratios of NMHCs rapidly r...