东营河口浅海贝类生态国家级海洋特别保护区大型底栖动物的群落结构特征

为了解东营河口浅海贝类生态国家级海洋特别保护区中大型底栖动物的群落结构及分布特征,于2019年对保护区内大型底栖动物进行了春、夏、秋、冬4个季度的详细调查,研究结果为:共采集大型底栖动物73种,优势种类为:彩虹明樱蛤(Moerellairidescens)、四角蛤蜊(Mactraveneriformis)、寡节甘吻沙蚕(Glycindegurjanovae)、三叶针尾涟虫(Diastylistricincta)、光滑河篮蛤(Potamocorbula laevis)、极地蚤钩虾(Pontocrates altamarimus)和马丁海稚虫(Spio martinensis)。大型底栖动物的年平均丰度为166 ind/m²,年平均生物量为14.30 g/m², Shannon-Wiener多样性指数(H′)平均值为2.14。聚类分析结果为调查区域的大型底栖动物分为两组群落(近岸区和远岸区),近岸区域形成以光滑河篮蛤和四角蛤蜊为主的群落,远岸区域形成以彩虹明樱蛤-寡节甘吻沙蚕为优势种类的群落,两者表现出不同的群落特征。ABC曲线分析表明,保护区内...     

热带东印度洋春季浮游植物群落结构空间特征分析

基于2013年3月至5月采集的热带东印度洋海域(10.0°S～4.0°N, 83.0°～97.5°E)浮游植物水样样品,分析了其种类组成、优势类群、细胞丰度等群落特征参数,综合比较了水平和垂向上浮游植物种类及丰度的差异性,初步探讨了其成因。结果表明:2013年春季热带东印度洋微型浮游植物共鉴定出306种,主要由硅藻、甲藻、金藻、蓝藻、裸藻和隐藻六大门类组成,其优势类群主要以粒径较小的隐藻、微型甲藻、菱形藻、环沟藻等为主。水平分布上,各水层浮游植物细胞丰度分布趋势相似,但斑块特征明显,其高值区位于88°E断面赤道以南次表层水域(30 m、75 m),局部区域细胞丰度值可达104 cells/L以上;与其毗邻的东南部、东部水域为低值区,并向赤道延伸。垂直剖面上,硅藻和甲藻广泛分布在各取样深度,但分布特征有明显的空间差异和规律,0 m、30 m大部分站位硅藻种类比例在0.2～0.3甚至更低,甲藻在0.7～0.8,随着水层加深(75 m、100 m、150 m、300 m),硅藻种类占比上升到0.5～0.6,甲藻降低到0.4～0.5,无论硅藻还是甲藻种类数75 m层最丰富。30 m和75 m水...     

平潭岛东北部近岸海域大型污损生物群落结构特征

于2017年6月至2018年5月在平潭岛东北部近岸海域开展污损生物生态研究,探讨了该海域大型污损生物的群落结构特点及演替趋势。周年模拟挂板试验结果显示,该海域大型污损生物隶属13门92种,以广分布暖水种为主,其中主要优势种为营固着生活的网纹藤壶(Amphibalanus reticulatus)、大室别藻苔虫(Biflustra grandicella)、三角藤壶(Balanus trigonus)和中胚花筒螅(Ectopleura crocea),以及自由生活的廉形叶钩虾(Jassa falcata)和齿掌细身钩虾(Maeropsis serratipalma)等。虽然该海域全年均有生物附着,但附着强度的季节性差异显著,附着盛期为6月至8月(生物量介于7 326.0～12 970.0 g/m2之间,以湿质量计),12月至次年2月(生物量介于39.5～1 580.5 g/m2之间)为附着淡季,而且污损生物摄食类型以悬浮物食者为主。温度和盐度是影响污损生物附着和分布的主要环境因素,水体透明度、水动力条件、地表径流和养殖等人类活动对污损生物的分布也有重要影响。     

底质细化对厦门潮下带文昌鱼栖息地大型底栖动物群落的影响

本文根据2014年至2017年在厦门文昌鱼保护区黄厝、南线十八线、鳄鱼屿和小嶝岛四处潮下带以及参照点白城潮下带获得的大型底栖动物和沉积物粒径数据,探讨底质细化对厦门潮下带文昌鱼栖息地大型底栖动物群落的影响。聚类分析表明个别黏土含量较高的取样站没有发现文昌鱼且大型底栖动物种数少。单因素方差分析表明,厦门潮下带部分大型底栖动物群落参数和优势种数量存在显著差异。底质粒径分析表明, 2017年9月,鳄鱼屿和白城潮下带黏土和粉砂含量高于黄厝、南线十八线和小嶝岛潮下带的黏土和粉砂含量。2016年夏季黄厝、南线十八线潮下带黏土和粉砂含量明显高于2014年夏季的黏土和粉砂含量。相关分析表明,5个大型底栖动物群落参数如物种数、栖息密度、生物量、多样性指数(H′)和丰度指数(d), 7个常见种的栖息密度和生物量与粉砂和黏土含量呈显著正相关,均匀度指数(J)和4种常见种的数量与粉砂和黏土含量无显著相关,白氏文昌鱼(Branchiostoma belcheri)的栖息密度和生物量与粉砂和黏土含量呈显著负相关。上述结果证实,黏土含量增加到15%和粉砂含量增加到60%有利于多数大型底栖动物栖息密度和生物量的增加,...     

Colonization and Disappearance ofMytilus galloprovincialisLam. on an Artificial Habitat in the Mediterranean Sea

AMytilus galloprovincialispopulation, settled on a new artificial habitat at 12 m depth in the Central Tyrrhenian Sea, was investigated for 10 years. The new substratum, located at a depth lower than the preferential range of the species, was colonized temporarily by mussels which reached very high densities and dominated the benthic community from their colonization until the third year. The length-frequency distribution analysis showed a progressively complex population structure with up to three cohorts. The yearly recruitments were observed once a year in spring. The growth curve provided a maximum length higher than that reported for shallow waters. Nevertheless, the gregarious habits of mussels and the reduced water movement caused edaphic modifications of the substratum, which was covered progressively by sediments and biodeposits (pseudofaeces). Consequently, the population structure was affected by a reduction of the newly recruited cohorts, and mussels disappeared after 5 years of colonization. This may be explained by the reduction in the substratum available for the first settlement (hydroid covering), as well as by the modification of the surface required for final settlement.     

The invertebrate benthic community of two solar salt ponds in Aveiro,Portugal

The invertebrate benthic community of two Aveiro salt pond systems was studied in order to evaluate its diversity, density and the influence of organic matter and salt production. Samples were collected monthly at Esmolas and Tanoeiras. Five groups of benthic organisms were found: Nemathelminthes, Annelida (Nereis diversicolor), Crustacea (Sphaeroma serratum andTanais cavolini), Insecta (Chironomidae), Bivalvia Mollusca (Cerastoderma edule, Spisula solida andMya arenaria) and Gasteropoda Mollusca (Hydrobia ulvae, Cingulla cingullus, Cingulla semistriata, Odostomia rissoides, Odostomia unidentata, Scrobicularia alba, Valvata cristata andPaludestrina acuta). The highest density of the benthic community was observed during the non-productive season in all but the crystallizing pond systems. In both salt ponds, salinity acted as limiting factor. The dominant group was Gasteropoda, although high densities of Bivalvia were recorded in some ponds. In the feeder pond and the channels, species diversity was highest in the Tanoeiras salt pond, probably because its physical and chemical characteristics allowed the development of stable communities.     

Hispanic Community Types and Assimilation in Mex-America

I argue that discrepancies among Hispanic assimilation models can be interpreted through three distinct types of Hispanic communities—continuous, discontinuous, and new. Continuous communities were founded by Hispanics and Hispanics have always been the majority population. As a result, Hispanics have not assimilated as predicted by traditional models. Discontinuous communities were originally settled by Hispanics, but eventually were filled by a minority population. Since WWII, many of these communities have experienced a Hispanic demographic resurgence making assimilation more problematic. Hispanics in new communities are recent immigrants to Anglo dominant communities and are more apt to follow the traditional assimilation model.     

Opening space for equity and justice in resilience: A subjective approach to household resilience assessment

While resilience has grown to become a well-established goal of policy and practice, assessing resilience remains an outstanding problem. To date, measurement has largely relied on the identification of proxy indicators, inevitably shaping what is measured in ways that reflect underlying assumptions, generalisations and approximations, and raising the question of whose values are being embedded into resilience. These concerns reflect recent interest in the role of recognition justice in resilience, and in particular how marginalisation from meaning-making processes creates the conditions for the inequitable distribution of outcomes in practice. Here, we propose a two stage, subjective approach to resilience assessment, starting with rapid household interviews that invite participants to assess the likely impact of multiple shock and stressor storylines. In a second step, participatory qualitative methods are employed to support inductive investigation of resilience focused on the factors that differentiate those reporting relatively high and low resilience. We illustrate this using fieldwork data from 569 households in Bangladesh. This subjective approach enables households to engage in the production of knowledge about their resilience, revealing two core features of situated heterogeneity: the forms of difference, and the underlying causes. Underlying causes arise from interactions and feedbacks between social, political, economic and institutional conditions that are highly context specific, while significant forms of difference include intra-community and scalar heterogeneity; vulnerability to specific or generalised shocks; and the role of undesirable practices in securing resilience. The results underline the need for resilience to be assessed in relation to local understandings of precarity, and through the expression of senses of justice that inform local conceptions of wellbeing. This means moving beyond positivist approaches and placing epistemic diversity at the centre of resilience assessment, enabling the production of a situated understanding of how and why resilience is differentiated, and offering an analytical starting point from which policy and practice can drive towards equitable resilience.     

Short-term bacterial reactivity of nitrogen-enriched seawater of a eutrophic lagoon

We carried out, in September, a 24 h experiment to determine the potential reactivity of bacterial communities found in the sea water in Arcachon Basin (France). To create eutrophic systems, batches of seawater were enriched with 30 mgl^?1 of either ammonium chloride or amino acids. Samples were taken every 3 h. Quantitative measurements were made of direct counts (AODC), biomass and ATP content. The heterotrophic bacterial communities were defined in terms of their catabolic potentialities and ‘specific’ diversity. Bacterial heterotrophic activity was established by measuring heterotrophic uptake and the mineralization percentage of labelled glucose or amino acids. From these data, ratios of AMP/ATP and P/B were calculated where P is the uptake of labelled substrate and B is the biomass.After the nitrogen enrichment an increase of the respiration was seen at first. After 6 h, a biomass peak appeared associated with a continuous increase in the number of cells. Bacterial growth was concurrent with a qualitative modification of the community: UAI increased, and diversity dropped. A less diversified community resulted suggesting an immature ecological state (zymogenous bacterial). Low values of respiration percentage (20%) characterized high growth yields.     

论产业集群的知识协作机制

产业集群的知识协作机制包括：信任机制和知识共享机制。其信任机制表现为：集群信任的形成是企业个体(或私人)的内在利益诉求的必然结果,也是集群环境下市场选择与市场竞争监督的“社会实施”的产物;其知识共享机制表现为：集群的空间集聚与信任特征创造了“面对面交流”的有利条件,集群的社会文化特征促进集群整体默会性知识的扩散与共享,集群的网络特征加速知识外溢与创意流动,为群内企业工作人员的知识开发与创造构筑协作平台。