渔业资源增殖放流的生态风险及其防控措施

渔业资源增殖放流作为国内外水生生物资源养护领域普遍采用的一种做法, 其在提升增殖种类资源量的同时, 也会给野生资源种类和增殖水域生态系统健康带来诸多生态风险。现阶段, 系统评价增殖放流的生态风险、实施有效的生态风险防控已成为构建负责任增殖放流模式的必然要求。本文从种群、群落和生态系统3个层面系统评述国内外渔业资源增殖放流生态风险研究领域的最新进展, 阐述相应的生态风险防控措施, 以期为我国渔业资源增殖放流的生态风险防控工作提供理论参考。

     

福建省农地流转后农户经营行为差异的实证分析

以福建省为例开展入户问卷调查，按农户在流转中不同的地位进行分类，对流转过程中农户的意愿和行为差异以及农地流转后农户分化所形成的农业经营格局进行分析，结果发现：土地从年龄较大、老年人口较多的贫困家庭以及较为年轻化的富裕家庭流出，向家庭经济状况较差的年轻化家庭流入；农地流转多以口头实现；在农村实际发生的农地流转规模远高于官方统计数字。     

Higher nitrogen and phosphorus immobilization in bioflocs is associated with higher temperature and increased suspended solids in shrimp farming with biofloc technology

High stocking density aquaculture can result in major environmental impacts such as waste disposal with high organic matter. In order to overcome this issue, biofloc technology (BFT) has arisen as an alternative to lower effluent nutrient loading by promoting dense microbial communities that control water quality through the assimilation of inorganic nutrients. Given the central role of microorganisms in nutrients storage, the aim of this study was to evaluate the elemental composition of bioflocs and free‐living microorganisms and to determine which environmental factors are associated with the variation in their stoichiometric ratios (C:N:P) in shrimp farming systems. Samples were taken in marine shrimp farms, and the stoichiometric ratios from bioflocs and free‐living microorganisms were analysed, as well as physical and chemical water quality variables. The C:N ratios were lower, and N:P ratios were higher in the free‐living microorganisms than bioflocs. The C:P and N:P ratios of the biofloc were lower at higher temperature and total suspended solids (TSS). We concluded that the elemental composition of the bioflocs is richer in C and P and that systems with higher temperature and higher TSS have a greater ability to absorb and immobilize these elements in the bioflocs.     

基于网络游记分析的游客环境责任行为

旅游业的迅猛发展给目的地生态环境带来了巨大压力，游客环境责任行为是降低游客环境影响，提高目的地环境质量的重要途径。网络空间的环境责任行为主要有垃圾处理行为、资源保护行为、节能减排节水行为、教育行为、参与环保活动行为等。影响游客的环境责任行为主要有态度因素、环境知识、教育和能力因素、习惯因素、榜样和从众因素、规制规范因素和支持因素等。环境责任行为产生的环境绩效主要有环境质量、景观质量、人类福祉、个体身心健康等。环境责任行为模型包括各类影响因素，影响因素影响环境行为，环境行为指向环境绩效。     

苦瓜花粉母细胞减数分裂行为研究

研究苦瓜花粉母细胞的减数分裂行为,发现苦瓜花粉母细胞减数分裂中细胞质分裂类型为同时型,并且在减数分裂过程中存在不同步现象。在苦瓜花粉母细胞细胞核分裂中,从前期I到中期I,核仁逐渐消失,到前期Ⅱ又重新出现,随后消失。同时,从前期I到中期I,染色体开始收缩并逐渐变得清晰,到末期I时,苦瓜染色体发生解螺旋并逐渐模糊,前期Ⅱ再次变得清晰。研究还发现,苦瓜花粉母细胞减数分裂前期I和前期II中,存在多核仁现象。苦瓜减数分裂过程中产生部分多分孢子,这可能与逆境及染色体不同步分离相关。     

国内“负责任旅游”研究综述

指出了随着人们对“大众旅游”给旅游目的地环境、经济、社会文化带来的负面影响的关注，“负责任旅游”应运而生。国外对“负责任旅游”的研究开始于1965年，到目前为止，已经形成了独立的学科研究体系。国内对“负责任旅游”的研究相对较晚，对国内“负责任旅游”的相关文献进行了研究，分析了我国“负责任旅游”的研究进展。     

县级林业主管部门在林改中的工作职责

遂川县林业产权制度改革试点工作．经过8个月来的艰苦努力，取得了阶段性的成果，得到了上级部门的肯定和省市领导的好评。县级林业部门在林改中应该履行什么职责？笔者的体会是：“当好参谋，主动服务，狠抓落实”。     

Dysregulated metabolism and behaviors by disrupting gut microbiota in prenatal and neonatal mice

The live microbiota ecosystem in the intestine plays a critical role in maintaining the normal physiological and psychological functions in both animals and human beings. However, the chronic effect of microbiota disturbances during prenatal and neonatal developing periods on animal's health remains less studied. In the current study, pregnant ICR mice were fed with an antibiotic diet (7-g nebacitin [bacitracin-neomycin sulphate 2:1]/kg standard diet) from day 14 of conception, and their offspring were provided with the same diet till the termination of the experiments. Dams treated with antibiotics showed increased body weight along with enlarged gut. Antibiotic-treated offspring revealed decreased bodyweight, increased food, water, and sucrose intake. Administration of antibiotics affected corticosterone responsivity to acute 20 min restraint challenge in male pups. In behavior tests, female pups showed decreased movement in open field while male pups revealed decreased latency to open arms in elevated plus maze test and immobility time in tail suspension test. Together, these results suggested that early antibiotic exposure may impact on the food intake, body weight gain, and emotional behavior regulation in mice.     

分段光照对蛋用型北京油鸡生产性能的影响

本试验对分段光照和连续光照条件下蛋用型北京油鸡的生产性能、采食时长、产蛋时间进行了研究。结果表明分段光照对蛋鸡的开产日龄没有明显影响,对产蛋前期产蛋率、耗料量的影响差异显著(P<0.05),对平均蛋重的影响差异显著(P<0.05),对料蛋比的影响差异极显著(P<0.01);对产蛋中期产蛋率、蛋重、耗料量、料蛋比影响均差异极显著(P<0.01);不同光照制度下蛋鸡的采食高峰时间和采食时长不同,产蛋高峰均集中在上午时段。分段光照和开灯时间早的试验组,蛋用型北京油鸡产蛋中前期的生产性能较好。     

固相合成MnO_2纳米棒的电容性能及其PbO改性研究

本文采用表面活性剂(PEG-400)辅助固相氧化法制备了二氧化锰纳米棒。借助X-射线衍射测试(XRD)、红外光谱测试(FT-IR)和透射电镜(TEM)等对产物晶型结构、形貌大小等进行了分析。测试结果表明所得样品为α-MnO2,其平均直径为10～15nm左右,平均长度在100～150nm左右。通过循环伏安法和恒流充放电测试探讨了所得MnO2纳米棒的超级电容器性能,试验结果表明:电流为2.0mA时,所得电极的初始放电比容量为88F/g。掺杂2%PbO的改性MnO2具有更好的电容性能,当充放电电流为2.0mA时,该改性MnO2的放电比容量为109F/g,比改性前提高了约24%。