Temporal and spatial variation in the Nazaré Canyon (Western Iberian margin): Inter-annual and canyon heterogeneity effects on meiofauna biomass and diversity

The Nazaré Canyon on the Portuguese Margin (NE Atlantic) was sampled during spring-summer for three consecutive years (2005–2007), permitting the first inter-annual study of the meiofaunal communities at the Iberian Margin at two abyssal depths (~3500 m and ~4400 m). Using new and already published data, the meiofauna standing stocks (abundance and biomass) and nematode structural and functional diversity were investigated in relation to the sediment biogeochemistry (e.g. organic carbon, nitrogen, chlorophyll a, phaeopigments) and grain size. A conspicuous increase in sand content from 2005 to 2006 and decrease of phytodetritus at both sites, suggested the occurrence of one or more physical disturbance events. Nematode standing stocks and trophic diversity decreased after these events, seemingly followed by a recovery/recolonisation period in 2007, which was strongly correlated with an increase in the quantity and bioavailability of phytodetrital organic matter supplied. Changes in meiofauna assemblages, however, also differed between stations, likely because of the contrasting hydrodynamic and food supply conditions. Higher meiofauna and nematode abundances, biomass and trophic complexity were found at the shallowest canyon station, where the quantity, quality and bioavailability of food material were higher than at the deeper site. The present results suggest that even though inter-annual variations in the sedimentary environment can regulate the meiofauna in the abyssal Nazaré Canyon, heterogeneity between sampling locations in the canyon were more pronounced.     

Plant diversity as a good indicator of vegetation stability in a typical plateau wetland

Biotic indicators have been widely used to monitor wetland health. However, few studies have explicitly evaluated if plant diversity could serve as a useful community-level indicator of wetland stability, especially when wetlands are confronted with anthropogenic perturbations. Based on three-year record of wetland plant species abundance in Napahai plateau wetland, Shangri-la under the influence of varying anthropogenic perturbation types, our study tests the impact of such perturbations on plant richness and the relationship between ecosystem temporal stability and plant richness, and further assesses the effectiveness of using plant diversity indicator to probe ecosystem temporal stability of Napahai plateau wetland and the potential mechanisms. The results showed that anthropogenic perturbations could have contributed significantly to realistic variation in plant diversity, and further demonstrated that ecosystem temporal stability was positively related to realistic variation in plant diversity. In particular, communities with high levels of diversity might have better capacity to dampen perturbation impacts than communities with low levels of diversity, and statistical averaging could have played an important role in causing greater stability in more diverse communities. Also, asynchrony might have a stabilizing effect on community stability, and diversity could have stabilized communities through both species asynchrony and population stability propagation. Therefore, our results suggest that plant diversity could be used as a useful indicator of the stability conditions of plateau wetland ecosystems confronted with anthropogenic perturbations, and the preservation of plant communities at sufficient abundance and diversity is necessary for maintaining healthy plateau wetlands and for sustaining their essential ecosystem functions and services.     

Patterns and causes of uncertainty in the American Community Survey

In 2010 the American Community Survey (ACS) replaced the long form of the United States decennial census. The ACS is now the principal source of high-resolution geographic information about the U.S. population. The margins of error on ACS census tract-level data are on average 75 percent larger than those of the corresponding 2000 long-form estimate. The practical implications of this increase is that data are sometimes so imprecise that they are difficult to use. This paper explains why the ACS tract and block group estimates have large margins of error. Statistical concepts are explained in plain English. ACS margins of error are attributed to specific methodological decisions made by the Census Bureau. These decisions are best seen as compromises that attempt to balance financial constraints against concerns about data quality, timeliness, and geographic precision. In addition, demographic and geographic patterns in ACS data quality are identified. These patterns are associated with demographic composition of census tracts. Understanding the fundamental causes of uncertainty in the survey suggests a number of geographic strategies for improving the usability and quality ACS.     

2011年龙江县玉米农田土壤湿度变化及其对玉米生长的影响

以黑龙江省龙江县玉米主栽品种葫科336为试材,采用自然条件下对比观测田间试验,研究分析不同土壤湿度对玉米生长的影响。结果表明：2011年龙江县试验田不同表层(0-30 cm)土壤湿度均呈下降趋势。试验田不同表层土壤湿度对玉米生长的影响存在差异,不同土壤湿度对玉米绿叶叶面积、植株干物重影响明显,在一定土壤湿度范围内,土壤相对湿度每升高1 %,叶面积增加28.338 cm²,土壤无旱对叶面积增加具有正效应,对玉米果实重量的增加也呈有利趋势。     

两阶段视角下我国海洋科技绿色创新效率研究——基于网络超效率EBM模型和DEA窗口分析

文章构建海洋科技绿色创新两阶段模型,将网络超效率EBM模型和DEA窗口分析相结合测度了我国沿海地区2008—2017年海洋科技绿色创新整体和分阶段效率。结果显示：考察期内整体效率均未实现DEA有效,研发与转化阶段的低效是其内在原因;整体效率与研发效率变化趋势高度相似;区域间效率水平差异比较明显,2011年后整体及阶段效率水平均呈现“东部较高、南部次之、北部较低”的态势;研究期内“高研发高转化”型地区仅有江苏、浙江、广东。     

基于CESM1.2.2模拟的浪致混合对末次冰盛期和工业革命前气候的影响

海洋上层垂向混合在模式中发挥重要的作用,以往的研究表明垂向混合的不足使得模拟的海洋温度和混合层深度与观测存在显著偏差。前人提出一种修正方案,考虑波浪产生的垂向混合,将由表面风作用下产生的波浪这样一个实际物理过程的湍混合进行参数化,其结果被证实能够显著提高模式模拟和预报的准确性。本文首次将浪致混合引入海气耦合的古气候模式,基于末次冰盛期和工业革命前2种不同的气候条件,探究浪致混合在海气耦合模式中的作用。在不同气候背景下,由于风场强度的不同,导致末次冰盛期浪致混合的强度小于工业革命前,但2个气候时期都体现出中纬度混合强度最大的特点。将浪致混合加入到气候模式中,模拟结果表明：中纬度海域2个时期都出现海表面降温而次表层升温的现象,但末次冰盛期的表面降温强度弱于工业革命前状态;不同月份下的模拟结果显示,在南北半球的夏季,海洋表层温度的降温最为显著。中纬度海域海洋上混合层深度在年平均条件下2个气候背景时期都出现加深现象,但末次冰盛期的加深程度弱于工业革命前;不同月份下的模拟结果显示,在南北半球的冬季,混合层加深的变化达到极值。另一方面,在高纬度海域,末次冰盛期的海表面温度出现了显著升高,这是由于浪致混合导致海冰的减少进而引发海洋表层升温。最后将末次冰盛期的模拟结果与代用资料进对比,发现浪致混合使得72%的数据点模拟结果与代用数据的差异减少。     

渭河咸阳至宝鸡段冬季水鸟群落多样性初步研究

为厘清渭河越冬水鸟年度变化情况及各种人为干扰对越冬水鸟的影响,2016—2018年对渭河咸阳至宝鸡段越冬水鸟进行了监测。结果表明:(1)该区域共记录越冬水鸟33种,隶属于7目12科25属,其中国家重点保护鸟类6种;(2)雁形目鸭科鸟类物种最多,达15种,水鸟优势种为赤麻鸭、斑嘴鸭、绿翅鸭、绿头鸭、普通秋沙鸭;(3)2018年Shannon-Wiener多样性指数和均匀性指数均最高,2016年水鸟群落的丰富度指数最高;(4)人为干扰对水鸟的影响较大,但多以中度干扰和较弱干扰为主,在人为干扰和非人为干扰状态下,水鸟物种数差异不显著,水鸟总数量差异显著。在不同干扰类型下,水鸟物种数差异显著,水鸟总数量差异不显著。     

绿色化学法在金银多金属分析中的应用研究

本文采用HCl-HNO3-NH4HF2-KClO3封闭溶样,在(NH2)2CS介质中,原子吸收光谱法测定矿石中的Au、Ag。方法能有效避免AgCl、PbCl2沉淀和Au、Ag的硅酸盐包裹体,以及W、Mo和Sb、Pb等在Au富集过程中的竞争吸附与容量法测定的终点干扰。应用ICP-AES可在该介质中完成金矿样品中Ag、Cu、Pb、Zn、As、Sb等的同时测定。方法绿色环保,操作简单、快速,稳定性好,准确度和精密度高,适合于大批量金矿样品的分析测定。     

The green economy in Tanzania: From global discourses to institutionalization

The purpose of this paper is to examine the transfer of the green economy from a global discursive level to institutionalization at the national level in Tanzania. While there is a growing amount of research discussing technological aspects of the green economy, less attention has been paid to policy implications and governance aspects, especially in developing countries. There is an increasing emphasis on technological and market-based solutions to environmental challenges globally and in the developed part of the world. However, in developing countries, ‘green growth’ often implies transformed control over natural resources – under schemes that are often driven from abroad. Over the last five to ten years, investments aimed at increasing productivity in the rural agricultural sector in developing countries have become a focus area of the green economy, but various concepts of green have become confused. Such (mis-) interpretation of the green economy has consequences for implementation and outcomes of various ‘green’ projects. Drawing on governmentality as well as the concept of institutional bricolage, I examine how the green economy discourse and policy at the global level have been re-shaped and re-interpreted to fit the existing agri-business initiative of the Southern Agricultural Growth Corridor of Tanzania (SAGCOT), which has been championed as a model for green economy implementation in Africa. I discuss how the green discourse has been ‘grabbed’ as an opportunity to ‘greenwash’ SAGCOT in its establishment and institutionalization.     

Participation and resistance: Alternative seafood marketing in a neoliberalera

This paper suggests that detrimental effects of certain neoliberal fisheries policies are key drivers behind the development of alternative seafood marketing programs in North America. It examines the structures, market and non-market values, and challenges of these programs. The primary aim of the research, based on interviews involving 20 programs and a conference workshop, was to advance understanding of the market value of alternative seafood marketing to fishers and communities. However, the importance of a broader set of non-market values was repeatedly highlighted by those engaged in these programs. Overall, the research suggests that alternative seafood marketing can enable fishers to participate in fisheries managed by neoliberal, market-based policies, through the promotion of market values along their diverse value chains. At the same time, alternative seafood marketing appears to resist market-based fishing systems, sometimes through the promotion of broader, non-market outcomes. Common challenges along these alternative seafood value chains highlight the structural conflicts that exist while simultaneously participating in and resisting neoliberal fisheries structures.