Copper and zinc in an ecological series of talitroidean Amphipoda (Crustacea)

Summary Cu and Zn concentrations were determined for the following talitroidean amphipods, Hyale nilssoni (Rathke), Talitrus saltator (Montagu), Talorchestia deshayesii (Audouin), Orchestia mediterranea Costa, O. gammarellus (Pallas), O cavimana Heller and Arcitalitrus dorrieni (Hunt) in September 1986 from sites in W. Britain (mostly Scottish). To minimize size effects, only animals >2mg body dry weight were included in analyses. Only Talorchestia (Cu & Zn) and O. cavimana (Zn) showed any residual relationship between metal concentration and dry weight. Log transformed data for concentrations of each metal against log dry wt. in all species were compared by ANCOVA. Copper and zinc concentrations of males and females were not significantly different in O. gammarellus, O. mediterranea and T. deshayesii, though Cu (but not Zn) concentrations differed with sex in O. cavimana. The order of species when ranked according to an ascending series of Cu concentrations (at standard body weight) reflected their ecological zonation from sea to land closely, with species living proximal to the sea having lowest Cu concentrations. The 6 talitrid species all had similar Zn concentrations but the Zn concentration of H. nilssoni was considerably lower. There was a relationship between Cu and Zn concentrations in individuals of only one species (O. gammarellus). Data on Cu and Zn concentrations for O. gammarellus derived from the same site in September 1983 were almost exctly the same as in September 1986. The possible impact of seasonal variation on haemocyanin levels is discussed.     

Carotenoids in Ostrea edulis L. (Bivalvia: Ostreacea) from the lagoon of Venice (Italy)

By means of columnar and thin-layer chromatography the presence of carotenoids in Ostrea edulis L. (Bivalvia: Ostreacea) from the Lagoon Venice (Italy), was studied.The following carotenoids were founds: -, -, -carotene, -carotene epoxide, lutein (free and epoxide from), zeaxanthin, diatoxanthin, mutatoxanthin and astaxanthin. The dominating carotenoids were lutein.The total contents varied within the range of 5.4–8.1 µg/g wet weight.     

陆地碳循环研究中的模型方法

陆地碳循环是全球变化研究中的重要内容,碳循环模型已成为研究陆地碳循环的必要方法．其中气候变化、大气ＣＯ２浓度上升以及人类活动引起的土地利用和土地覆盖变化导致陆地生态系统在结构、功能、组成和分布等方面的变化及其反馈关系对陆地碳循环的影响是模型模拟的关键问题．生物地理模型和生物地球化学模型是碳循环模型的两大类型,建模方法、模型性质、特点和应用范围各异．碳循环模型的发展方向是综合两类模型的特点,建立全球动态碳循环模型．     

Obstacle perception by insect antennae during terrestrial locomotion

Abstract. Insect antennae bear several types of sensilla including chemo-receptors, hygroreceptors, thermoreceptors and mechanoreceptors. A large proportion of sensilla is chemoreceptors, providing olfactory function. Pro-prioreceptors located on the antennae provide information on the position of these organs and are used in flight control. This type of sensillum is present in most insects and might serve other functions. We tested the hypothesis that antennae are used to perceive obstacles in the path of walking beetles. When adult Colorado potato beetles, Leptinotarsa decemlineata (Say), touch an obstacle with their antennae during terrestrial locomotion, they modify the angle of their body to allow the tarsi of one prothoracic leg to reach the top of the obstacle. Our results demonstrate that antennae, by their movements and their position ahead of the beetle, provide information on the presence of the obstacle necessary to initiate step-up behaviour. Furthermore, the change in the body angle needed to increase the reach of the prothoracic leg and step on the obstacle, is proportional to the height of the obstacle. Since the eyes are not involved in the process, normal behaviour can be performed in the dark.     

Heparin in molluscs: chemical, enzymatic degradation and C and H n.m.r. spectroscopical evidence for the maintenance of the structure through evolution

The structural features and anticoagulant activity of heparins isolated from three species of molluscs (Anomalocardia brasilian, Donnax striatus and Tivela mactroides) are reported. It is shown by chemical analyse, type of products formed by action of heparinase and heparitinase II, anticoagulant activity, ¹³C and ¹H n.m.r. spectroscopy, that the mollusc heparins are virtually indistinguishable from heparins present in mammalian tissues. These data, taken as a whole, suggest that heparin has maintained its main structural features through evolution. The implications of these findings are discussed.     

Tracking predator density dependence and subterranean predation by carabid larvae on slugs using monoclonal antibodies

1. Subterranean carabid larvae are more numerous than surface‐active adults, yet very little is known about their ecological significance, dietary preferences or ability to regulate populations of prey species, particularly pests. Part of the reason for this is that predator–prey interactions beneath the soil are almost impossible to observe. 2. Extensive field studies have shown that adult Pterostichus melanarius (Illiger) can affect the temporal and spatial dynamics of their slug prey. However, if larvae too are feeding on slugs, this could radically affect overall predator–prey dynamics. 3. We tested the hypotheses that P. melanarius larvae would kill and consume two slug species, Deroceras reticulatum Müller and Arion intermedius Normand, under laboratory and semi‐field conditions, and that there would be no significant difference in rates of predation on these slug species. 4. A new monoclonal antibody was developed that was capable of detecting the presence of slug proteins in the guts of P. melanarius larvae. 5. Pterostichus melanarius larvae killed both A. intermedius and D. reticulatum in the laboratory, feeding to a greater extent, and growing more rapidly, on the latter. The larvae were equally effective at reducing numbers of both slug species in a crop of wheat grown in semi‐field mini plots, but predation was affected by density‐dependent intra‐specific competition amongst the beetle larvae. 6. Future modelling of the dynamic interactions between carabids and slugs will need to take into account predation by larvae.     

Major muscle systems in the larval caenogastropod,Ilyanassa obsoleta,display different patterns of development

This study describes the anatomical and developmental aspects of muscular development from the early embryo to competent larval stage in the gastropod Ilyanassa obsoleta. Staining of F‐actin revealed differential spatial and temporal patterns of several muscles. In particular, two major muscles, the larval retractor and pedal retractor muscles originate independently and display distinct developmental patterns similar to observations in other gastropod species. Additionally, together with the larval retractor muscle, the accessory larval muscle developed in the embryo at the trochophore stage. Therefore, both these muscles develop prior to ontogenetic torsion. The pedal retractor muscle marked the most abundant growth in the mid veliger stage. Also during the middle stage, the metapodial retractor muscle and opercular retractor muscle grew concurrently with development of the foot. We show evidence that juvenile muscles, such as the buccal mass muscle and siphon muscle develop initially during the late veliger stage. Collectively, these findings substantiate that larval myogenesis involves a complex sequence of events that appear evolutionary conserved within the gastropods, and set the stage for future studies using this model species to address issues concerning the evolution and eventual fates of larval musculature in molluscs. J. Morphol., 2009. © 2009 Wiley‐Liss, Inc.     

东北林区净初级生产力及大兴安岭地区林火干扰影响的模拟研究

森林净初级生产力(NPP)是衡量陆地碳源/汇的重要参数, 准确地估算森林生态系统的NPP, 同时通过引入干扰因子以期更加完整地描述生态学过程及其响应是目前森林生态系统碳循环研究的重点。因此, 该研究基于北方生态系统生产力(BEPS)模型, 结合遥感数据和气象数据等模拟2003年东北林区NPP; 将BEPS模型模拟的结果作为整合陆地生态系统碳收支(InTEC)模型的参考年数据, 模拟东北林区1901-2008年的NPP, 并在InTEC模型中加入林火干扰数据, 模拟大兴安岭地区1966-2008年的森林NPP。结果显示: 在1901年, 东北林区NPP平均值仅为278.8 g C·m^-2·a^-1, 到了1950年, NPP平均值增加到338.5 g C·m^-2·a^-1, 2008年NPP平均值进一步增加到378.4 g C·m^-2·a^-1。其中长白山地区的NPP平均值始终最高, 大兴安岭次之, 小兴安岭始终最低。到了2008年, 大、小兴安岭和长白山地区的NPP平均值都有较大涨幅, 其中涨幅最高的是长白山地区, 达到200-300 g C·m^-2·a^-1; 东北三省中, 黑龙江和吉林的NPP平均值和总量都比较高, 辽宁相对较低, 但相比于1901年的涨幅最高, 达到70%; 重大火灾(100-1000 hm²)对NPP的影响不是很大, 而特大火灾(>1000 hm²)的影响比较大, 使NPP下降幅度达到10%左右, 其他火灾年份, NPP增长迅速并保持在较高水平; 对火灾面积在100000 hm²以上的4个年份的NPP进行分析, 发现NPP平均值都大幅度下降, 其中1987年下降幅度最大, 为11%以上。     

Ecological fidelity of open marine molluscan death assemblages: effects of post-mortem transportation, shelf health, and taphonomic inertia

Based on 38 molluscan datasets from modern open shelf settings, disturbance from human activities – especially anthropogenic eutrophication (AE) – has the strongest negative effect on the fidelity of death assemblages to local living communities, suggesting that the composition of the death assemblage has lagged behind changes in the living community (taphonomic inertia). Fidelity is poorest where shelves are both AE and narrow (≤ 50 km from shore to the 200-m isobath), suggesting that cross-shelf post-mortem transportation might contribute bias, but this does not dominate and shelf width does not emerge as significant among non-AE shelves. Clear signatures of post-mortem transportation are present only in four shoreface datasets, all from wide shelves, that receive abundant allochthonous specimens from adjacent estuaries or rocky intertidal zones.
Shelves experiencing minimal human impact yield fidelity estimates that are most relevant for evaluating (paleo)ecological trends. There, death assemblages are on average 25% richer than a single census of the living molluscan community and show high similarity in taxonomic composition and species relative abundance that, based on a very limited number of studies, is comparable to or better than the agreement found among successive live censuses. Molluscan death assemblages on open shelves are thus generally good samplers of living community diversity and composition under natural conditions, and where the community is undergoing anthropogenic modification, retain a strong record of the precursor community. Taphonomic inertia will be strongest where the change in the community has been especially strong (outside the normal range of natural variability) and/or where the 'new' community has lower net rates of shell input than its precursor, so that input only slowly dilutes the time-averaged skeletal remains of the 'old' community.     

Are extracellular osmolality and sodium concentration determined by Donnan effects of intracellular protein charges and of pumped sodium?

Although we are used to attribute almost identical extracellular fluid (ECF) sodium concentrations in birds, amphibians, reptiles, and mammals to the composition of the primordial oceans in which, presumably, all life originated, this interpretation is not supported by geological data suggesting that the ocean salinity was never much lower than the present-day values, still four times higher than our plasma sodium.Here presented interpretation is that the similar ECF salt concentrations are dictated by the opposed Donnan effects on the cell membrane. The only way for the cell to reach the osmotic equilibrium is to alter cell volume, until concentration of nondiffusible intracellular ions (mainly charges on intracellular proteins) is equal to the ECF restricted ions (mainly Na⁺ ions, restricted by pumping out of cells).The achievement of electroneutrality requires that the sum of all anions equals concentration of positive ions in the cell (mainly K⁺). Negative charges on cytoplasmic proteins are the most stable component among ionized particles and other ions have to adapt to their concentration. Positive and negative soluble intracellular ions are all osmotically active and to achieve balance of osmotic forces on the cell membrane, the sum of their intracellular concentrations must equal the concentration of osmotically active extracellular particles. Since almost half the osmotically active ECF particles are sodium ions, the ECF sodium concentration seems related to concentration of charges on cytoplasmic proteins and concentration of intracellular phosphates.Our ancestors could not leave the salty ocean and move to brackish, or even fresh waters, without adequate regulation of their ECF sodium concentration and osmolality. Concentration of charges on cytoplasmic proteins or of intracellular phosphate buffers could not be altered, since this would compromise cell functioning. The remaining solution was to maintain the lowest ECF Na⁺ concentration effective in counteracting the average Donnan effect of charges on cytoplasmic proteins. When the optimal ECF sodium concentration had once become the reference point for osmoreceptors (controlling thirst and ADH secretion) and other regulatory mechanisms (secretion of renin/angiotensin/aldosterone, natriuretic factors), it made an important survival advantage that allowed spreading of animal life in fresh water and conquering of earth. The actual common value had to be a compromise that reduces the average osmotic burden on body cells to zero. Individual cells can reduce eventual residual osmotic forces on their membrane through altering cell volume by chloride shift, and by modulating the Na⁺K⁺-ATPase function.