Boletín 3798 de registros. Del 30 Enero de 2015

Registros Públicos

First Report of a Toxic Nodularia spumigena (Nostocales/Cyanobacteria) Bloom in Sub-Tropical Australia. II. Bioaccumulation of Nodularin in Isolated Populations of Mullet (Mugilidae)

Fish collected after a mass mortality at an artificial lake in south-east Queensland, Australia, were examined for the presence of nodularin as the lake had earlier been affected by a Nodularia bloom. Methanol extracts of muscle, liver, peritoneal and stomach contents were analysed by HPLC and tandem mass spectrometry; histological examination was conducted on livers from captured mullet. Livers of sea mullet (Mugil cephalus) involved in the fish kill contained high concentrations of nodularin (median 43.6 mg/kg, range 40.8-47.8 mg/kg dry weight; n = 3) and the toxin was also present in muscle tissue (median 44.0 mu g/kg, range 32.3-56.8 mu g/kg dry weight). Livers of fish occupying higher trophic levels accumulated much lower concentrations. Mullet captured from the lake 10 months later were also found to have high hepatic nodularin levels. DNA sequencing of mullet specimens revealed two species inhabiting the study lake: M. cephalus and an unidentified mugilid. The two mullet species appear to differ in their exposure and/or uptake of nodularin, with M. cephalus demonstrating higher tissue concentrations. The feeding ecology of mullet would appear to explain the unusual capacity of these fish to concentrate nodularin in their livers; these findings may have public health implications for mullet fisheries and aquaculture production where toxic cyanobacteria blooms affect source waters. This report incorporates a systematic review of the literature on nodularin measured in edible fish, shellfish and crustaceans.

Phylogenetic studies of cyanobacterial lichens

Phylogenetic studies of cyanobacterial lichens Lichens are symbiotic assemblages between fungi (mycobiont) and green algae (phycobiont) or/and cyanobacteria (cyanobiont). Fossil records show that lichen-like symbioses occurred already 600 million years ago. Lichen symbiosis has since then become an important life strategy for the Fungi, particularly for species in the phylum Ascomycota as approximately 98% of the lichenized fungal species are ascomycetes. The taxonomy of lichen associations is based on the mycobiont. We reconstructed, using DNA sequence data, hypotheses of phylogenetic relationships of lichen-forming fungi that include species associated with cyanobacteria. These hypotheses of phylogeny should form the basis for the taxonomy. They also allowed studies of the origin and the evolution of specific symbioses. Genetic diversity and phylogenetic relationships of symbiotic cyanobionts were also studied in order to examine selectivity of cyanobionts and mycobionts as well as possible co-evolution between partners involved in lichen associations. The suggested circumscription of the family Stereocaulaceae to include Stereocaulon and Lepraria is supported. The recently described crustose Stereocaulon species seem to be correctly placed in the genus, although Stereocaulon traditionally included only fruticose species. The monospecific crustose genus Muhria is also shown to be best placed in Stereocaulon. Family Lobariaceae as currently delimited is monophyletic. Within Lobariaceae genus Sticta including Dendriscocaulon dendroides form a monophyletic group while the genera Lobaria and Pseudocyphellaria are non-monophyletic. A new classification of Lobariaceae is obviously needed. Further studies are however required before a final proposal for a new classification can be made. Our results show that the cyanobacterial symbiotic state has been gained repeatedly in the Ascomycota while losses of symbiotic cyanobacteria appear to be rare. The symbiosis with green algae is confirmed to have been gained repeatedly in Ascomycota but also repeatedly lost. Cyanobacterial symbioses therefore seem to be more stable than green algal associations. Cyanobacteria are perhaps more beneficial for the lichen fungi and therefore maintained. The results indicate a dynamic association of the lichen symbiosis. This evolutionary instability will perhaps be important for the lichen fungi as the utilization of options will perhaps enable lichens to colonize new substrates and survive environmental changes. Some cyanobacterial lichen genera seem to be highly selective towards the cyanobiont while others form symbioses with a broad spectrum of cyanobacteria. No evidence of co-evolution between fungi and cyanobacteria in cyanolichens could be demonstrated.

多孔冲击式分级采样器的流体力学分析及参数设计

本文描述了多孔冲击式采样器的工作原理,用流体力学方法作了分析计算,并提出了参致设计方法。最后将实验结果和理论作了比较。用本文所述方法设计的HFS-1多孔采样器,经测试性能达到国家标准。

Das Klima um Grönland - 1996

Based on air temperature data from three sites of West and East Greenland, on ice charts for the area 54°N, 71°N and 20°W, 70°W, and on CTD profile observations around Greenland, the annual variability of climate is shown. Mean monthly air temperature data from Nuuk/West Greenland reveal the long-term interannual changes of air temperature anomalies. The warming trend which was observed during November, December 1995 was maintained into 1996 for about five months. Thus, spring warming of the near surface water layers, especially on the shallow bank areas off West Greenland has been favoured. As a result of mild air temperatures over most of 1996, sea ice conditions were about normal around Greenland and off eastern Canada. Subsurface observations indicate considerable warming of the 0-200 m water layer off West Greenland. The thermal anomaly of this layer amounts to +1.59K, which is the second highest value on record since the warm 1964 event. The warmer than normal conditions as recorded since November 1995 off East and West Greenland, point at intermediate warming which is characteristic of the second half of the recent decades. The long-term trend of air temperature anomalies off West Greenland points, however, still at cooling, a trend which is persistent since the early 1970s. As the potential driving mechanism for the intermediate warming in the Labrador Sea area, the sea level air pressure gradient between Iceland and the Azores is identified. The 1996 value of this gradient, the North Atlantic Oscillation (NAO) Index, is strongly negative and this represents the flow of mild air masses from the midlatitude Atlantic Ocean to the Greenland/Labrador Sea region. Accordingly, air temperature anomalies indicated unusual warming during the month of February which amounted to >2K in the region of Baffin Land, Labrador and Greenland.

不同地区螺旋藻室外大规模养殖的研究

在武汉、汕头和湛江进行的螺旋藻室外大规模生产过程中，对藻种的选择，培养基调控，单位面积产量和产品质量进行了研究。结果表明极大螺旋藻ＦＡＣＨＢ４３８表现了较好的适应性和较稳定的生物量生产率；钝顶螺旋藻ＦＡＣＨＢ４３９在武汉地区和湛江地区的生物量生产率略低于极大螺旋藻ＦＡＣＨＢ４３８。但是在低温季节钝顶螺旋藻ＨＢ８３在湛江地区仍能表现出一定的适应能力和生物量生产率。分析结果表明三个地区生产的螺旋藻粉产品质量相差不大。在不同地区或季节选用不同的藻种搭配是保持螺旋藻生产的连续性和稳定的生物量生产率的一项重要措施。

辽河油田大民屯凹陷沙三段生油岩热模拟成烃实验研究

大民凹陷是一个典型的“小而肥”的含油气盆地，研究其生油岩热模拟成烃特征对探讨其油气成因，为今后本地区油气的进一步勘探以及寻找类似的含油气盆地具有重要意义。热模拟实验建立在“干酪根热降解成烃”理论基础上。中外学者的热模拟实验结果表明：在实验室内进行的人工热模拟实验是可靠的，可以近似模拟地质体中有机质的热演化过程，温度是有机质热演化的决定因素目前热模拟实验主要分为两类即热解法和封闭或半封闭体系内热模拟法。