Effect of feeding selectivity on the transfer of methylmercury through experimental marine food chains

The present study established an experimental marine food chain of three levels (microalgae → zooplankton → fish) to investigate the effect of feeding selectivity on the transfer of methylmercury (MeHg) through the food chain. Total Hg concentrations in Chlorella sp., Nitzschia closterium and Isochrysis galbana exposed to 1 μg L⁻¹ MeHg for three days were 27.91, 32.74 and 40.03 μg g⁻¹ respectively and were significantly different (p < 0.05) between species. Moina mongolica and Artemia sp. primarily selected Chlorella sp. as the sole diet, though the Artemia sp. partly grazed on I. galbana as well. Harpacticus uniremis, however, preferred to graze N. closterium and I. galbana and avoided Chlorella sp. The varying concentration of Hg in the microalgae species as well as the selectivity of zooplankton to the algal diet resulted in varying Hg accumulation in three zooplankton species (M. mongolica < Artemia sp. < H. uniremis with total Hg concentrations of 0.14, 0.66 and 0.82 μg g⁻¹, respectively). Scophthalmus maximus and Paralichthys olivaceus mainly preyed on H. uniremis and partly on M. mongolica, while Fugu rubripes primarily preyed on M. mongolica and secondarily on Artemia sp. Thus, similar reasoning as above could explain the significant difference in Hg accumulation in the fish (S. maximus > P. olivaceus > F. rubripes with total Hg concentrations of 0.0042, 0.0031 and 0.0020 μg g⁻¹, respectively). These investigations suggested feeding selectivity plays a key role in the transfer of MeHg along marine food chains.     

Unexpected Results from China's Agricultural Subsidies Policy

Given the huge demand for food created by China's large population and the high cost of transporting food across such a large nation, a food security strategy based on local self-sufficiency seems vital. To encourage agricultural production, agricultural subsidies have therefore been implemented since 1997. Although subsidies to support food production in China arose from the desire to combat poverty and hunger, they may have instead led to adverse health impacts, food insecurity, and environmental degradation because the complexity of socioeconomic systems prevented governments from fully understanding the relationships among the many factors in such systems. China therefore faces enormous challenges before it can attain sustainable food production at levels high enough to end hunger, without undesirable consequences.     

Traditional irrigation techniques in MENA with a focus on Tunisia

ABSTRACT

Due to their efficiency, revitalized traditional techniques for irrigation management of scarce water resources have been suggested as a way to at least partially cope with the present water crises in the Middle East. A better irrigation management includes re-using treated wastewater in agriculture. Treated wastewater should also be used in industrial processes, thus contributing to a more efficient overall water management. However, the most important change leading to better water management is improving water efficiency in agricultural irrigation. Traditional water management techniques have an important role in many Middle East and North African (MENA) countries. Besides bringing more water to a thirsty population, they can also contribute to the societal awareness, and recognition of the great diversity of cultural and social values water has to human civilization.

EDITOR D. Koutsoyiannis; ASSOCIATE EDITOR P. Hubert     

Seeing benevolently: Representational politics and digital race formation on ethnic food tour webpages

The aim of this paper is to extend studies of food media and racialisation by applying Nakamura’s (2002, 2008) concepts of digital race formation and cybertype to the webpages of an ethnic food tour in southwestern Sydney. Whilst the literature on food media, and racialisation and food practices are burgeoning, little attention to date has been given to racialization and gendering on food websites, and particularly those for social enterprises, which have hybrid commercial and social aims. Given that Nakamura has focused on a range of new media but not webpages, we draw on analytic frameworks on visual racism from Van Leeuwen (2008) and interactivity and aesthetics by Adami (2014, 2015) to provide a detailed case study analysis of how the visual and verbal meaning-making strategies and the technological affordance of interactivity produce racialised and gendered cybertyping and Othering. Our analysis shows that racialised femininity is deployed to touristify a region seen by racist media to be criminalised, masculine and foreign. We conclude by arguing that methods for analysing meaning-making strategies in new media need to be developed in food studies and that food social enterprises should see their representational work as part of their social mission.     

Tracing technique of stable 15N isotope: an application in study of mariculture

Ｔｒａｃｉｎｇｔｅｃｈｎｉｑｕｅｏｆｓｔａｂｌｅ~（１５）Ｎｉｓｏｔｏｐｅ：ａｎａｐｐｌｉｃａｔｉｏｎｉｎｓｔｕｄｙｏｆｍａｒｉｃｕｌｔｕｒｅ￥ＨｏｎｇＡｓｈｉ；ＬｉＷｅｎｑｕａｎａｎｄＷａｎｇＭｉｎｇｌｉａｎｇ（Ｔｈｅｐｒｏｊｅｃｔｉｓｓｕｐｐｏｒ?..     

不同大小玉筋鱼摄食、生长和生态转换效率的比较

本研究将Eggers模型移入实验室大型玻璃钢水槽中，以细脚长蜮为饵料，在流水条件下，比较了黄渤海主要中上层小型鱼类玉筋鱼大小两种体重组的摄食、生长和生态转换效率等生态能量学特征。结果表明：小个体的摄食率、生长率和生态转换效率分别为12．36gW．W．／100g／d或12．44kJ／100g／d，2．22gW．W．／100g／d或9．09kJ／100g／d，0．18％W．W．或0．73％kJ；大个体的摄食率、生长率和生态转换效率分别为9．16gW．W．／100g／d或9．22kJ／100g／d，0．83gW，W．／100g／d或3．41kJ／100g／d，0．09％W．W．或0．37％kJ。不管是以湿重还是以能量计算，小个体的都比大个体的要高。     

我国"蓝色粮仓"关联产业发展现状、问题及对策分析

"蓝色粮仓"是包含海产品生产、加工及海洋水产资源环境养护等众多关联产业的集合体,是保障我国粮食和营养安全、推进海洋强国战略和国家生态文明建设的重大举措。然而,"蓝色粮仓"关联产业粗放式的发展模式给近海渔业资源及生态环境造成了不同程度的损害,制约了我国"蓝色粮仓"的可持续发展。文章系统地分析了我国"蓝色粮仓"关联产业的发展现状与存在资源衰退状况严重、近海捕捞难以维持、养殖环境问题突出、水产品安全问题凸显等问题,并提出了控制近海捕捞产量,推进捕捞业转型升级、优化海水养殖模式,提高生态和经济效益、加强水产品精深加工,提高产业价值链、加强渔业资源保育工作、完善各项保障措施等对策,以求为我国"蓝色粮仓"建设决策提供参考依据。     

全球变化对中国粮食安全的影响分析

以斯德哥尔摩环境研究所(SEI)建立的粮食需求和供应模型为基础,同时采用Ds和Shaw建立的全球变化各因子对粮食需求和供给影响的模型对其变量进行修正,结合唐国平、李秀彬的结果,模拟计算了全球变化条件下,我国未来粮食需求量和产量。在分析中发现:受全球变化的影响,在保持人民消费水平持续增长的条件下我国未来粮食生产有可能不能满足需求增长的要求,存在7～8%的粮食缺口。但是,由于全球变化的各个因素都存在很大的不确定性,而且技术进步对增加粮食产量有很大促进作用。计算结果揭示,只要采取正确的措施来尽量减少全球变化带来的不利影响,危机是可以避免的     

台湾海峡浮游植物生物量和初级生产力的粒级结构及碳流途径

本文研究了1997年8月、1998年2-3月、8月和1999年8月台湾海峡浮游植物生物量和初级生产力的粒级组成、各粒级生物量和初级生产力变动（包括年际变动及其影响因子。结果表明，台湾海峡微型（简称NANO）和微微型浮激植物（简称PICO）占优势，贡献率分别达34%-48%、34%-40%，小型浮游植物（简称MICRO）仅占12%-27%。粒级组成和各粒级生物量存在着明显的季节和年际变化，如1997年夏季三种粒级浮游植物生物量均明显低于其它年份，PICO和MICRO组份呈1998年夏季高于1997年和1999年夏季，而NANO组份则呈1998年夏季低于1997年和1999年夏季。PICO组份对初级生产力的贡献最大，达45%-50%，而NANO和MICRO组份对初级生产力的贡献相近，为19%-32%；PICO组份的同化系数明显高于NANO和MICRO组份。初步分析了初级生产的碳流途径，表明台湾海峡初级生产的碳将有25%经异养细菌的“二次”生产而进入微食物环，36%通过原生动物（主要是异养鞭毛虫）摄食“打包”的作用后进入微食物环，即近60%的初级生产的碳经微食物环的两个起点分别进入微食物环，表明微型生物食物网在该海域生源有机碳转换过程中起重要作用。