Life history costs of olfactory status signalling in mice

Large body size confers a competitive advantage in animal contests but does not always determine the outcome. Here we explore the trade-off between short-term achievement of high social status and longer-term life history costs in animals which vary in competitive ability. Using laboratory mice, Mus musculus, as a model system, we show that small competitors can initially maintain dominance over larger males by increasing investment in olfactory status signalling (scent-marking), but only at the cost of reduced growth rate and body size. As a result they become more vulnerable to dominance reversals later in life. Our results also provide the first empirical information about life history costs of olfactory status signals. Received: 15 December 1999 / Revised: 6 June 2000 / Accepted: 24 June 2000     

焦化场地典型多环芳烃类污染物精细化风险评估

为准确评估多环芳烃(PAHs)污染土壤对人体的健康风险,解决目前基于总量风险评估导致土壤PAHs修复目标值过严的问题,采用德国标准研究院颁布的生物可给性测试方式研究了石家庄某焦化厂土壤中苯并[b]荧蒽(BBF)、苯并[k]荧蒽(BKF)、苯并[a]芘(BAP)、茚并[1,2,3-cd]芘(IPY)和二苯并[a,h]蒽(...     

Testis size variation in the greenfinch Carduelis chloris : relevance for some recent models of sexual selection

Interspecific evidence that testis size responds to selection caused by sperm competition has been obtained from many taxa. However, little is known about the sources of intraspecific variation in testis size, although such variation may have functional significance. Variation in testis size and asymmetry was studied within and between eight geographically separated (and genetically differentiated) populations of greenfinches Carduelis chloris. The relationships between testis size and plumage brightness (degree of yellowness) and the prevalence of haematozoan infections were also investigated in three of these populations, as they related to the predictions of the immunocompetence handicap hypothesis, and Møller's hypothesis relating directional testis asymmetry to phenotypic quality. There were large differences between populations in testis size, with males from northern populations having larger testes than those from southern populations. Within populations, large testes were associated with larger body size and greater age. When the influence of these factors was removed statistically, males with large testes were more likely to be infected with haematozoan parasites, and had brighter yellow plumage. No evidence was found that directional asymmetry in testis size was related to either of these measures of phenotypic quality. These results are consistent with the hypothesis that males with large testes, while signalling higher phenotypic quality as revealed by increased plumage brightness, also pay a cost in terms of reduced immunocompetence, revealed by the increased probability of infection in these males. That these patterns were similar in three different populations adds further strength to these conclusions. Our results suggest that studying the sources of variation in testis size among individuals can reveal interesting processes in sexual selection.     

水环境中的有机磷阻燃剂及其生物富集和生物转化研究进展

随着世界范围内对溴代阻燃剂的禁用,有机磷阻燃剂(OPFRs)被作为替代品广泛应用于建筑、纺织、化工、电子以及家装材料等行业,生产和使用量逐年上升.由于OPFRs在环境和生物体中普遍检出,且多种化合物具有致癌性、神经毒性和生殖毒性,对生态环境和人体健康造成潜在威胁,目前已成为国际上的一个研究热点.笔者重点综述了河流、湖泊...     

Determination of selected fate and aquatic toxicity characteristics of acrylic acid and a series of acrylic esters

Acrylic acid, methyl acrylate, ethyl acrylate, and butyl acrylate are commercially important and widely used materials. This paper reports the results of a series of fate and aquatic toxicity studies. The mobility in soil of acrylic acid and its esters ranged from 'medium' to 'very high'. Calculated bioconcentration factors ranged from 1 to 37, suggesting a low bioconcentration potential. Acrylic acid and methyl acrylate showed limited biodegradability in the five day biochemical oxygen demand (BOD5) test, while ethyl acrylate and butyl acrylate were degraded easily (77% and 56%, respectively). Using the OECD method 301D 28-d closed bottle test, degradability for acrylic acid was 81% at 28 days, while the acrylic esters ranged from 57% to 60%. Acrylic acid degraded rapidly to carbon dioxide in soil (t1/2 < 1 day). Toxicity tests were conducted using freshwater and marine fish, invertebrates, and algae. Acrylic acid effect concentrations for fish and invertebrates ranged from 27 to 236 mg/l. Effect concentrations (LC50 or EC50) for fish and invertebrates using methyl acrylate, ethyl acrylate, and butyl acrylate ranged from 1.1 to 8.2 mg/l. The chronic MATC for acrylic acid with Daphnia magna was 27 mg/l based on length and young produced per adult reproduction day and for ethyl acrylate was 0.29 mg/l based on both the reproductive and growth endpoints. Overall these studies show that acrylic acid and the acrylic esters studied can rapidly biodegrade, have a low potential for persistence or bioaccumulation in the environment, and have low to moderate toxicity.     

Fenton试剂处理选矿废水机理研究

研究了用Fenton试剂处理选矿废水中残余的黄药,分别考查了氧化时间、反应初始pH值、Fe2+浓度及H2O2用量对黄药降解效果的影响,用正交试验确定了4个因素的最好条件。结果表明:初始pH值和H2O2用量是影响去除效果的主要因素;氧化时间为60 m in,反应初始pH=4,[Fe2+]=20 mg/L,[H2O2]=20 mg/L,黄药的浓度为125 mg/L时,黄药的去除率达到99.5%;初步探讨了Fenton试剂净化废水中黄药的机理是.OH自由基先将黄药氧化为过氧化黄原酸盐,再将其氧化为CO2,黄药得到去除。     

The Influence of Mycorrhiza on Uranium and Phosphorus Uptake by Barley Plants from a Field-contaminated Soil (7 pp)

Background Recent studies indicated that arbuscular mycorrhizal fungi (AMF) play important roles in plant accumulation of uranium (U) from contaminated environments, but the impacts of fertilization practices on functioning of the symbiotic associations, which are crucial factors influencing plant nutrition and growth responses to mycorrhiza, have rarely been considered. Materials and Methods In a greenhouse experiment, a bald root barley mutant (brb) together with the wild type (wt) were used to test the role of root hairs and AMF in uranium (U) uptake by host plants from a U contaminated soil. Nil, 20 and 60 mg KH2PO4-P kg–1 soil were included to investigate the influences of phosphorus (P) fertilization on plant growth and accumulation of U. Results Dry matter yield of barley plants increased with increasing P additions and wt produced significantly higher dry weight than brb. Mycorrhiza markedly improved dry matter yield of both genotypes grown at nil P, whereas only brb responded positively to mycorrhiza at 20 mg P kg-1. At the highest P level, mycorrhiza resulted in growth depressions in both genotypes, except for the roots of wt. In general, plant P concentrations increased markedly with increasing P additions and in response to mycorrhiza. Mycorrhiza and P additions had no significant effects on shoot U concentrations. However, root U concentrations in both genotypes were significantly increased by mycorrhiza. On the other hand, shoot U contents increased with increasing P levels, while 20 mg P kg-1 stimulated, but 60 mg P kg-1 marginally affected the U accumulation in roots. Root length specific U uptake was moderately enhanced both by root hairs and strongly enhanced by mycorrhiza. Moreover, non-inoculated plants generally had higher shoot-root ratios of U content than the corresponding inoculated controls. Conclusion Our study shows that AMF and root hairs improves not only P acquisition but also the root uptake of U, and mycorrhiza generally decreases U translocation from plant root to shoot. Hence, mycorrhiza is of potential use in the phytostabilization of U contaminated environments. Perspectives The complex impacts of P on U accumulation by barley plants suggested that U behavior in mycorrhizosphere and translocation along the soil-fungi-plant continuum as affected by fertilization practices deserve extensive studies for optimizing the function of mycorrhizal associations for phytoremediation purposes.     

Living in an oasis: Rapid transformations,resilience, and resistance in the North Water Area societies and ecosystems

Based on lake sediment data, archaeological findings, and historical records, we describe rapid transformations, resilience and resistance in societies and ecosystems, and their interactions in the past in the North Water area related to changes in climate and historical events. Examples are the formation of the polynya itself and the early arrival of people, ca. 4500 years ago, and later major human immigrations (different societies, cultural encounters, or abandonment) from other regions in the Arctic. While the early immigrations had relatively modest and localised effect on the ecosystem, the later-incoming culture in the early thirteenth century was marked by extensive migrations into and out of the area and abrupt shifts in hunting technologies. This has had long-lasting consequences for the local lake ecosystems. Large natural transformations in the ecosystems have also occurred over relatively short time periods related to changes in the polynya. Finally, we discuss the future perspectives for the North Water area given the many threats, but also opportunities.     

Chemical methods and phytoremediation of soil contaminated with heavy metals

The effects of chemical amendments (calcium carbonate (CC), steel sludge (SS) and furnace slag (FS)) on the growth and uptake of cadmium (Cd) by wetland rice, Chinese cabbage and wheat grown in a red soil contaminated with Cd were investigated using a pot experiment. The phytoremediation of heavy metal contaminated soil with vetiver grass was also studied in a field plot experiment. Results showed that treatments with CC, SS and FS decreased Cd uptake by wetland rice, Chinese cabbage and wheat by 23-95% compared with the unamended control. Among the three amendments, FS was the most efficient at suppressing Cd uptake by the plants, probably due to its higher content of available silicon (Si). The concentrations of zinc (Zn), lead (Pb) and Cd in the shoots of vetiver grass were 42-67%, 500-1200% and 120-260% higher in contaminated plots than in control, respectively. Cadmium accumulation by vetiver shoots was 218 g Cd/ha at a soil Cd concentration of 0.33 mg Cd/kg. It is suggested that heavy metal-contaminated soil could be remediated with a combination of chemical treatments and plants.     

Polycyclic aromatic hydrocarbons in the bulk precipitation and surface waters of Northern Greece

Bulk (wet and dry) precipitation and surface water sampling was undertaken in the main plain of central Macedonia in Northern Greece. Fourteen polycyclic aromatic hydrocarbons (PAHs) included in the US EPA's priority pollutant list were analysed. The concentrations determined in bulk precipitation were in general within the range of values worldwide reported. Concentrations were highest in the cold months. Deposition fluxes of PAHs were of the same order of magnitude as reported data. The greatest values were found when high concentrations of PAHs in precipitation coincided with large precipitation amounts. The concentrations of PAHs in surface waters (main rivers, tributaries, ditches, etc) were in general lower than those in bulk precipitation, and among the lowest reported for European rivers, excepting Np and Ph. Bulk deposition and domestic effluents are suggested as being the main PAH sources into surface waters.