拉普拉塔河流域以及巴塔哥尼亚地区及相关海域水生态栖息地的改变

本文描述了南美大陆南部陆地和东南沿海地区环境特性及水生栖息地和群落的现状(GIWA巴塔哥尼亚大陆架亚区),结果来自一项GIWA项目框架任务所完成的一份全面评估,绝大部分依据的是公开发表的数据.分析主要集中在跨边界水资源目前的情况和人类活动带来的影响.内陆水体的栖息地和群落变化主要是由为发电和其他用途而建的水坝和水库引起的.从活水环境到净水环境影响了生境,造成了生物群落的改变.在拉普拉塔(La Plata)河流域,外来入侵物种使本地物种消失.过度捕捞和污染影响了生物多样性,造成了海洋栖息地质量下降.本篇文章讨论了相关的原因,讨论了布宜诺斯艾利斯省和渔业资源由两国共享的阿根廷-乌拉圭公共渔业区对沿海生态环境的政策选择.     

Prenatal demonstration of a cervical myelocystocele

Myelocystocele is a rare spinal cord disorder and has not been described prenatally. We report a case in which prenatal ultrasound and magnetic resonance imaging (MRI) demonstrated a posterior cervical mass which was initially thought to be a meningocele or an atypical cystic hygroma. Surgery performed at 1 day of age showed this to be a myelocystocele. Therefore, the differential diagnosis of an extracranial cystic mass in the posterior cervical region should be expanded to include myelocystoceles.     

智利的APELL:推进一项面向港口的战略

智利的经验显示,APELL原则可以与当地应急规划举措相结合.APELL对工业事故的非排他性和不是唯一答案"思路也可以应用于其它类型的紧急状况,包括自然灾害(或自然灾害与工业灾害的组合).因此,APELL特别适合应用于港口.这种APELL思路促进了潜在受影响社区的参与--关于港口的另一个重要考虑.     

Larval development of <Emphasis Type="Italic">Lightiella magdalenina</Emphasis> (Crustacea,Cephalocarida)

The larval development of the newly discovered cephalocarid from Mediterranean sea, Lightiella magdalenina, was analysed using light and scanning electron microscopy. Twenty-nine larval specimens, divided into 15 metanaupliar and 2 juvenile stages of development, were found. The first six metanaupliar stages had an even number (6, 8, 10, 12, 14 and 16) of trunk segments including telson. The condition of 20 trunk segments, typical of the adult, was reached after another 4 stages by the addition of a single segment per stage. At this tenth stage, the larvae had an incomplete number of trunk limbs. Another five stages were needed to complete the cephalic appendage development, passing from the metanaupliar to the juvenile stage, characterized by loss of the naupliar enditic process of the second antenna. Trunk limbs development was completed during the last two juvenile stages. According to the ontogenetic data reported for Hutchinsoniella macracantha and Lightiella incisa, these seventeen stages probably do not represent the complete developmental series. Nevertheless, they allow us to clarify the main features of cephalocarid ontogeny and show specific differences in the development of both the trunk segments and appendages.     

Patterns of seagrass (Posidonia oceanica) flowering in the Western Mediterranean

The intensive reconstructive sampling (1957–2004, 39 localities), a systematic direct observation (1992–2004, 1 locality) and particular direct observations (66 localities) of Posidonia oceanica meadows were analysed together with temporal series of flowering available in the literature (19 localities). This allowed the examination of temporal and spatial variability in annual flowering prevalence (FP, the fraction of meadows flowering in a given year) and of annual meadow flowering intensity (FI, number of inflorescences per shoot) for the period 1979–2004 across the Western Mediterranean, as well as spatial variability of flowering frequency (FF, the fraction of years that a given meadow has flowered) and shoot flowering probability (Pf, fraction of flowering stalks appeared per annual segment). Each year, on an average 17% of the investigated meadows flowered, ranging from 3 to 86% of meadows among the years. The highest annual FP and FI values were obtained in 2003 (FP=0.86 and mean FI=0.23±0.03 inflorescences shoot⁻¹). A secondary peak of FP and mean FI occurred 9 years earlier, in 1994 (FP=0.44 and mean FI=0.08±0.02). Both peaks of flowering occurred after hot summers. Flowering synchrony in particular years across the Western Mediterranean and clines of increased meadow flowering frequency towards the North and East, suggests the existence of large-scale environmental mechanisms controlling the floral induction. On the other hand, meadow FF and Pf were highly heterogeneous among and within the meadows, indicating that local factors also may play a significant role in flowering induction. When flowering, the Western Mediterranean meadows showed an average 0.11±0.02 inflorescences shoot⁻¹, but FI greatly varied among and along the series (from 0.002 to 0.54 inflorescences shoot⁻¹) and decreased significantly with depth but was independent of meadow shoot density and meadow latitude or longitude. The shoot flowering probability was quite low (0.007±0.002 inflorescences shoot⁻¹ year⁻¹) and exponentially increased with shoot age.     

Trace gases and particulate matter emissions from wildfires and agricultural burning in Northeastern Mexico during the 2000 fire season

An inventory of air pollutants emitted from forest and agricultural fires in Northeastern Mexico for the period of January to August of 2000 is presented. The emissions estimates were calculated using an emissions factor methodology. The inventory accounts for the emission of carbon monoxide (CO), methane, nonmethane hydrocarbons, ammonia, nitrogen oxides, and particulate matter (PM). Particulate matter emissions include estimates for fine PM and coarse PM. A total of 2479 wildfires were identified in the domain for the period of interest, which represented approximately 810,000 acres burned and 621,130 short tons emitted (81% being CO). The main source of information used to locate and estimate the extent of the fires came from satellite imagery. A geographic information system was used to determine the type of vegetation burned by each fire. More than 54% of the total area burned during the period of study was land on the State of Tamaulipas. However, >58% of the estimated emissions came from the State of Coahuila. This was because of the mix of vegetation types burned in each state. With respect to the temporal distribution, 76.9% of the fires occurred during the months of April and May consuming almost 78% of the total area burned during the period of study. Analysis of wind forward trajectories of air masses passing through the burned areas and 850-mb wind reanalyses indicate possible transboundary transport of the emissions from Mexico to the United States during the occurrence of the major wildfires identified.     

Effects of lindane on the photosynthetic apparatus of the cyanobacterium<Emphasis Type="Italic">anabaena</Emphasis>

INTENTION, GOAL, SCOPE, BACKGROUND: Cyanobacteria have the natural ability to degrade moderate amounts of organic pollutants. However, when pollutant concentration exceeds the level of tolerance, bleaching of the cells and death occur within 24 hours. Under stress conditions, cyanobacterial response includes the short-term adaptation of the photosynthetic apparatus to light quality, named state transitions. Moreover, prolonged stresses produce changes in the functional organization of phycobilisomes and in the core-complexes of both photosystems, which can result in large changes in the PS II fluorescence yield. The localization of ferredoxin-NADP+ reductase (FNR) at the ends of some peripheral rods of the cyanobacterial phycobilisomes, makes this protein a useful marker to check phycobilisome integrity. OBJECTIVE: The goal of this work is to improve the knowledge of the mechanism of action of a very potent pesticide, lindane (gamma-hexaclorociclohexane), in the cyanobacterium Anabaena sp., which can be considered a potential candidate for bioremediation of pesticides. We have studied the effect of lindane on the photosynthetic apparatus of Anabaena using fluorescence induction studies. As ferredoxin-NADP+ reductase plays a key role in the response to oxidative stress in several systems, changes in synthesis, degradation and activity of FNR were analyzed. Immunolocalization of this enzyme was used as a marker of phycobilisome integrity. The knowledge of the changes caused by lindane in the photosynthetic apparatus is essential for rational further design of genetically-modified cyanobacteria with improved biorremediation abilities. METHODS: Polyphasic chlorophyll a fluorescence rise measurements (OJIP) have been used to evaluate the vitality and stress adaptation of the nitrogen-fixing cyanobacterium Anabaena PCC 7119 in the presence of increasing concentrations of lindane. Effects of the pesticide on the ultrastructure have been investigated by electron microscopy, and FNR has been used as a marker of phycobilisome integrity. RESULTS AND DISCUSSION: Cultures of Anabaena sp. treated with moderate amounts of lindane showed a decrease in growth rate followed by a recovery after 72 hours of pesticide treatment. Concentrations of lindane below 5 ppm increased the photosynthetic performance and activity of the cells. Higher amounts of pesticide caused a decrease in these activities which seems to be due to a non-competitive inhibition of PS II. Active PS II units are converted into non-QA reducing, so called heat sink centers. Specific activity and amount of FNR in lindane-treated cells were similar to the values measured in control cultures. Release of FNR from the thylakoid after 48 hours of exposure to 5 ppm of lindane towards the cytoplasm was detected by immunogold labeling and electron microscopy. CONCLUSIONS: From these results, we conclude that the photosynthetic performance and activity of the cells are slightly increased in the presence of lindane up to 5 ppm. Moreover, in those conditions, lindane did not produce significant changes in the synthesis, degradation or activity of FNR. The high capability of Anabaena to tolerate lindane makes this cyanobacterium a good candidate for phytoremediation of polluted areas. RECOMMENDATION AND OUTLOOK: The results of this study show that cultures of Anabaena PCC 7119 tolerate lindane up to 5 ppm, without significant changes in the photosynthetic vitality index of the cells. However, a slight increase in phycobiliprotein synthesis is observed, which is related to total protein content. This change might be due to degradation of proteins less stable than phycobiliproteins. An identification of the proteins with altered expression pattern in the presence of the pesticide remains the subject of further work and will provide valuable information for the preparation of strains which are highly tolerant to lindane.     

Effects of herbicide and insecticide interaction on soil entomofauna under maize crop

The aim of this study was to evaluate the impact of the herbicide mixture nicosulfuron + atrazine, with or without the insecticide chlorpyrifos, onto soil entomofauna under maize crop. The treatments, applied 25 days after maize emergence, were represented by a weeded control without insecticide and herbicide, a weeded control with chlorpyrifos, and mixtures of nicosulfuron + atrazine, with or without chlorpyrifos. Arthropods populations, on the soil surface, as well as inside the soil under maize, were principally represented by mites (Arachnida: Acari), decomposer collembolans (Hexapoda:Parainsecta:Collembola) and predator ants (Hymenoptera:Formicidae). The nicosulfuron + atrazine mixture with chlorpyrifos and the isolated chlorpyrifos reduced the population dynamics of all insect groups on the soil surface compared to the weeded control. In the soil, mite and ant populations were reduced after application of the herbicide mixture with chlorpyrifos and of the isolated chlorpyrifos.