急性与亚慢性镉胁迫对河南华溪蟹消化系统亚细胞结构的影响

本实验运用透射电镜技术,观察了河南华溪蟹(Sinopotamon henanense)分别在镉29.0 mg·L-1急性染毒4 d和2.90 mg·L-1亚慢性染毒21 d后消化系统4种器官(食道、中肠、后肠和肝胰腺)亚显微结构的变化和损伤情况.结果显示:急性和亚慢性染毒均可导致各组织中细胞核变形、染色质浓缩边集、核固缩、核碎裂,线粒体空泡化、嵴缩短、融解甚至消失,但前者对各组织亚细胞的损伤更为严重;肝胰腺和中肠组织的病理变化较食道和后肠组织中的明显,镉胁迫后均可观察到上皮细胞内粗面内质网扩张变形、核糖体脱落,高尔基体形态结构异常,微绒毛排列紊乱、部分融解、断裂,出现大量的自噬溶酶体;食道和后肠的肌纤维水肿、肌原纤维排列疏松.急性与亚慢性镉处理均会对河南华溪蟹的消化系统产生毒害,造成各组织器官中细胞结构的严重损伤,且急性高浓度的镉暴露对机体造成的毒性影响较为严重.这些损伤会影响消化酶的合成和分泌等生理功能,导致机体失去正常的消化能力.     

Condition-dependent expression of melanin-based coloration in the Eurasian kestrel

Melanin is the most common pigment in animal integuments and is responsible for some of the most striking ornaments. A central tenet of sexual selection theory states that melanin-based traits can signal absolute individual quality in any environment only if their expression is condition-dependent. Significant costs imposed by an ornament would ensure that only the highest quality individuals display the most exaggerated forms of the signal. Firm evidence that melanin-based traits can be condition-dependent is still rare in birds. In an experimental test of this central assumption, we report condition-dependent expression of a melanin-based trait in the Eurasian kestrel (Falco tinnunculus). We manipulated nestling body condition by reducing or increasing the number of nestlings soon after hatching. A few days before fledging, we measured the width of sub-terminal black bands on the tail feathers. Compared to nestlings from enlarged broods, individuals raised in reduced broods were in better condition and thereby developed larger sub-terminal bands. Furthermore, in 2?years, first-born nestlings also developed larger sub-terminal bands than their younger siblings that are in poorer condition. This demonstrates that expression of melanin-based traits can be condition-dependent.     

Soil and preen waxes influence the expression of carotenoid-based plumage coloration

The signaling function of carotenoid-based plumage is mainly determined by the concentration of pigments in feathers. For this reason, most studies of the proximate control of coloration focus on processes during and preceding moult. In great tits Parus major, past research demonstrates that carotenoid-based plumage coloration honestly indicates male quality and, thus, may be a sexually selected signal. In this study, we investigate how dirt and preen oil influence the coloration of carotenoid-based feathers in the great tit. We collected six feathers from each individual bird; three feathers served as controls while the remaining three feathers were washed with a chloroform/methanol mixture to remove soil and preen waxes. We assessed plumage coloration using digital photography. This cleaning procedure slightly enhanced ornamentation; the experimentally cleaned feathers expressed hues shifted towards shorter wavelengths and expressed brighter overall coloration than control feathers. This is the first experimental study conducted on wild birds demonstrating that, in addition to pigment concentration, the presence of preen waxes and soils on feathers may contribute to variation in coloration.     

珠江口水域表层水体光合色素分布特征研究

于2011年2月对珠江口水域表层水体进行了调查,利用反相高效液相色谱测定了水体中19种光合色素的含量,研究了珠江口水域浮游植物特征色素组成及其分布特征。结果表明:表层水体主要特征色素为岩藻黄素、多甲藻素和别藻黄素,还存在少量的青绿素、19’-已酰基氧化岩藻黄素、二乙烯基叶绿素a。各光合色素具有明显的分布特征,如叶绿素a、叶绿素c2、岩藻黄素和多甲藻素等表现为珠江口水域内侧(淡水端)高,外海区(海水端)低的特点;19’-已酰基氧化岩藻黄素、玉米黄素、叶绿素b和青绿素等主要分布在外海区,在珠江口水域内侧未检出。根据光合色素分布特征,可以确定在珠江口海域存在的浮游藻种类包括硅藻、甲藻、隐藻、青绿藻和原绿球藻等浮游微藻。     

Habitat structure is associated with the expression of carotenoid-based coloration in nestling blue tits Parus caeruleus

We investigated how the expression of carotenoid-based plumage coloration (lightness and chroma) in nestling blue tits Parus caeruleus is associated with forest structure in oak forests of central Spain. We found evidence of a reduced expression of carotenoid-based coloration in nestlings growing up in successionally young and structurally simple forest territories. Our results suggest that breast feather coloration can be used as an indicator of nestling quality because nestlings with more intense yellow plumage coloration had larger body size and stronger immune responses to the injection of phytohemagglutinin (PHA). Given the association of forest structural complexity with carotenoid-based plumage coloration, our findings suggest that variation in habitat structure may have a significant impact on forest birds in their first stages of life which has implications for forest management practices.     

南岭东段含稀土矿花岗岩体中暗色包体地质特征——以陂头岩体为例

在野外地质调查和室内综合研究的基础上,通过研究南岭东段风化壳淋积型矿中含稀土矿花岗岩层中暗色包体的地质特征,发现分布在岩体中的大量暗色包体具流面和流线构造,主要组成矿物为石英、辉石和斜长石,具典型的辉长结构。暗色包体低硅、钾和钠,高钙、铝、镁、铁、钛和锰,属亚碱性—铝不饱和型;富集U、La、Pr、Nd、Sm、Dy,亏损Nb、Sr、Zr、Hf、Ti等微量元素;REE总量低于寄主含矿花岗岩层稀土总量,Ce和Eu具有明显的负异常。这些特征说明暗色包体的原岩可能来自早期基性岩,其形成与燕山早期陂头岩体的分异演化关系密切。与南岭地区花岗岩中此类暗色包体进行对比,有助于在该区寻找稀土矿床和稀有金属矿床。     

The liver but not the skin is the site for conversion of a red carotenoid in a passerine bird

Carotenoids may provide numerous health benefits and are also responsible for the integumentary coloration of many bird species. Despite their importance, many aspects of their metabolism are still poorly known, and even basic issues such as the anatomical sites of conversion remain controversial. Recent studies suggest that the transformation of carotenoid pigments takes place directly in the follicles during feather growth, even though the liver has been previously recognised as a storing organ for these pigments with a certain potential for conversion. In this context, we analysed the carotenoid profile of plasma, liver, skin and feathers of male Common Crossbills (Loxia curvirostra). Interestingly, the derivative feather pigment 3-hydroxy-echinenone was detected in the liver and in the bloodstream (i.e. the necessary vehicle to transport metabolites to colourful peripheral tissues). Our results demonstrate for the first time with empirical data that the liver may act as the main site for the synthesis of integumentary carotenoids. This finding contradicts previous assumptions and raises the question of possible inter-specific differences in the site of carotenoid conversion in birds.     

暗光缺氧条件下微囊藻的存活及胞内物质释放

蓝藻水华爆发期间,沉降至底泥-水界面的蓝藻会面临暗光缺氧胁迫.为研究沉降蓝藻的存活及释放物,模拟暗光缺氧条件,利用不同生长期的微囊藻进行了一系列的实验.结果表明,微囊藻可以在暗光缺氧条件下存活至少6d,释放的溶解性有机碳达到1.86mg C/mg Chl a.不同生长期对微囊藻的存活和释放物产生影响,其中培养55d的微囊藻存活时间最长,培养28d的微囊藻溶解性有机碳的释放量最高.本研究证实暗光缺氧条件下,微囊藻能够存活一段时间并释放有机碳,且存活时间和有机碳释放量与微囊藻生长期相关.     

癸二烯醛对3种常见浮游植物光合色素的影响

本研究选取东海原甲藻（Prorocentrum donghaiense）、并基角毛藻（Chaetoceros decipiens）和小普林藻（Prymnesium parvum）等3种常见海洋浮游藻类为材料,将处于指数生长期的藻细胞置于不同浓度的癸二烯醛（2E,4E-Decadienal,DEC）中,癸二烯醛是一种毒性较强的常见多不饱和醛,观察癸二烯醛对藻类光合色素种类及含量的影响。利用高效液相色谱技术检测到东海原甲藻含有5种光合色素,并基角毛藻含有8种光合色素,小普林藻含有9种光合色素,3种藻类的共有色素有4种。经浓度为1 mg/L癸二烯醛处理后,3种藻类的光合色素浓度无显著变化。癸二烯醛浓度为3 mg/L时,对东海原甲藻光合色素浓度产生显著的抑制作用,其所有色素浓度在第一天内几乎都未检测到;而并基角毛藻的硅甲藻黄素和硅藻黄素浓度均在第一天显著增加,其他色素浓度则无显著变化;小普林藻的硅甲藻黄素、硅藻黄素、岩藻黄素的浓度在实验的不同时间有不同程度下降,其余色素不受该浓度的癸二烯醛影响。当癸二烯醛浓度达到5 mg/L时,并基角毛藻中除玉米黄素外的其他7种光合色素浓度显著下降;小普林藻中除玉米黄素外的多种色素浓度受到显著影响。     

Estimates of dark ecosystem respiration of CO2 from the city of Calgary,Alberta

Carbon dioxide flux can be used as a criterion of the metabolism of terrestrial communities. A method has been developed to estimate this flux from urban areas during nocturnal periods characterized by stable air. The method assumes that biogenic and anthropogenic CO₂ emissions are proportional to one another. This assumption appears to be acceptable for average conditions in Calgary, Alberta, which is an “urban forest” situated in a prairie setting.Application of the method for estimating the CO₂ flux from Calgary's terrestrial ecosystem shows that dark respiration is absent during autumn and winter seasons. It is twice as great in summer as in spring. Its summer level is less than half that observed for an oak—pine forest in New York state. The lesser value is explainable in terms of Calgary's colder climate and the fact that a significant portion of the city is occupied by streets, houses, high-rise buildings and parking lots.     

The social side of spatial decision support systems: Investigating knowledge integration and learning

Spatial decision support systems (SDSS) represent a step forward in efforts to account for the spatial dimension in environmental decision-making. The aim of SDSS is to help policymakers and practitioners access, interpret and understand information from data, analyses and models, and guide them in identifying possible actions during a decision-making process. Researchers, however, report difficulties in up-take of SDSS by the intended users. Some suggest that this field would benefit from investigation of the social aspects involved in SDSS design, development, testing and use. Borrowing insights from the literature on science-policy interactions, we explore two key social processes: knowledge integration and learning. Using a sample of 36 scientific papers concerning SDSS in relation to environmental issues, we surveyed whether and how the selected papers reported on knowledge integration and learning. We found that while many of the papers mentioned communication and collaboration with prospective user groups or stakeholders, this was seldom underpinned by a coherent methodology for enabling knowledge integration and learning to surface. This appears to have hindered SDSS development and later adoption by intended users.     

Plumage coloration and nutritional condition in the great tit<Emphasis Type="Italic"> Parus major</Emphasis>: the roles of carotenoids and melanins differ

The size and coloration of some body characters seem to influence mate choice in many species. Most animal colours are either structural or based on melanin or carotenoid pigments. It has recently been suggested that carotenoid-based or structural coloration may be a condition-dependent trait, whereas melanin-based coloration is not; a difference that may be highly relevant when studying the evolution of multiple mating preferences. We tested this hypothesis in the great tit (Parus major). The size of the melanin breast band was not correlated to nutritional condition as estimated by the rate of tail growth (ptilochronology), controlling for locality, age, sex, year and season effects. However, the correlation was significant for the hue of yellow breast (carotenoid-based coloration), and the slopes of the regressions of the two pigments to growth bars differed significantly. These results suggest that the expression of the two traits may be regulated by different mechanisms.     

Airborne trace metals in snow on the Japan Sea side of Japan

Prevailing seasonal weather patterns produce a homogeneous distribution of snow from the coast to the mountains in the Hokuriku region on the Japan Sea (west) side of Japan.Daily snowfall was collected on polyethylene foils at six sites along the coast, in city areas and in the inland mountains. The samples were analyzed for pH and the soluble and insoluble fractions of Al, Cd, Cr, Cu, Fe, Mn, Pb and Zn. Comparison of the data from the various sites allowed an estimate of the regional background concentration of the trace metals. The contribution of trace metals derived from sea spray and Kosa-loess particles was found to be of minor importance to the regional background.The pH values of melted snow averaged around 4.6 over a range of 3 pH units, with the greatest fluctuations at the seaside and mountain sites. In the cities, these pH fluctuations occurred within a narrower and generally lower pH spectrum.     

基于光合色素的海南八门湾及其毗邻水域浮游植物生物量及类群组成研究

根据2010年4月（春季）、2011年8月（夏季）在海南八门湾及其毗邻水域的采样调查,采用CHEMTAX化学分类法对该区域的表层水的浮游植物生物量以及类群进行了研究。初步的研究结果表明:春季,生物量由湾内向外海增大,最高值出现在文昌河入八门湾处,金藻、硅藻为主要优势类群。生物量与溶解无机氮（DIN）、SiO₃2-、PO₄3-正相关,与盐度负相关,浮游植物与营养盐比值（N:P,Si:N）相关性不明显,硅藻与P显著正相关。夏季,生物量空间分布差异较小,最高值出现在文教河,蓝藻、金藻、硅藻为优势类群。浮游植物生物量及群落结构特征与营养盐含量和比值之间存在相关性。生物量与SiO₃2-正相关,与盐度负相关,绿藻与N:P比呈正相关关系,绿藻还同时与N正相关,硅藻与Si:N比正相关。     

Pigeon orientation: effects of the application of magnets under overcast skies

 To verify the existence of a magnetic compass in birds, researchers have often released homing pigeons under overcast skies that are equipped with bar magnets on various parts of their body. In particular, Keeton was successful in finding disorientation in overcast conditions in a first series of tests, but not in a second series. The experiments reported here attempt to explain this contradiction on the basis of findings obtained by releasing pigeons equipped in a way similar to that reported in Keeton's tests and pigeons equipped in a way similar to that reported by other authors. Received: 15 November 1999 / Accepted in revised form: 28 February 2000