Loss of Ostracoda biodiversity in Western Mediterranean wetlands

• 1. The coastal area of Valencia (Spain) in the Western Mediterranean is rich in freshwater and brackish wetlands. These areas are mostly protected for bird conservation but are also highly affected by human impacts. Six shallow lakes located in Ramsar wetland sites of this area were studied in order to assess past and present ostracod biodiversity and relate it to the status of the lakes, taking into consideration the indicator value of these easily fossilizable crustaceans.
• 2. In all the wetlands studied, ostracod taphocoenoses showed much higher species richness than the corresponding biocoenoses. This is expected from the time accumulative character of the taphocoenosis, but the trend is clearly evident in the most disturbed sites which indicated loss of ostracod diversity owing to human impacts.
• 3. By considering the ecology of most frequent species, multivariate ordination of both tapho- and biocoenoses showed trends within and between lakes in their limnological status, which were related mainly to water chemistry, and also to temporality and eutrophication to a certain extent. Some lakes have apparently lost most of their past ostracod community owing to an increasing trophic status in some cases and to modifications of the hydrological regime in others.

Copyright © 2007 John Wiley & Sons, Ltd.     

椭圆真星介的盐度与温度耐受性研究

研究了采自西藏绒马温泉的椭圆真星介（Eucypris elliptica Baird）在（25±1）℃下对NaCl的耐受性和在盐度S=0.37g/L下的温度耐受性。结果表明,椭圆真星介6h的半致死盐度LC50为32.14g/L（95%置信区间为21.66～42.62g/L）;12h的半致死盐度LC50为17.04g/L（95%置信区间为16.94～17.14g/L）;6h的高温半致死温度LT50为39.3℃（95%置信区间为38.7～40.0℃）;24h的高温半致死温度LT50为36.1℃（95%置信区间为35.6～36.6℃）。6h时,在26.36、32.00g/L的盐度水平下,椭圆真星介全部昏迷;24h时,在17.89、21.72、26.36、32.00g/L的盐度水平下,也全部昏迷。12h时,在42℃的温度水平下全部昏迷。野外采样结果表明,椭圆真星介能在6‰～22‰的盐度和32℃的温泉环境下正常存活,并且椭圆真星介对NaSO4＋MgSO4与NaCl的耐受性不同。     

Effect of grazer regulation and algal inoculation on photodependent nitrogen fixation in a wetland rice field

Summary A dry season field experiment conducted for two consecutive years highlighted problems of achieving increased populations of N₂-fixing blue-green algae (BGA) in wetland rice fields. Inoculation of non-indigenous BGA strains, either dried or as fresh viable inocula even at high levels of application, was unsuccessful. A limiting effect of grazing invertebrate populations on BGA establishment was evident, but other factors were involved. Reducing grazer pressure did not permit establishment of inoculated BGA; interspecific competition and environmental factors may explain the inoculation failure. Grazer regulation permitted the establishment of a fast-growing indigenous N₂-fixing Anabaena and the doubling of N₂-fixing activity over a control. Neither inoculation nor grazer control affected grain yields significantly.     

台湾海峡底栖介形类真喜萤属一新种(介形纲:喜萤科)

在分析台湾海峡综合科学调查的浮游生物样品时,发现底栖介形类真喜萤属Euphilomedes(Poulsen,1962)一新种:多节真喜萤Euphilomedes multiangular sp.nov.(♂),主要鉴别特征:1)壳后缘呈斜向截平状,并具3束短刺毛束;2)前器官由5节组成,是真喜萤属中雄性前器官分节最多的种类,最后一节的末端具3根尖刺;3)第2触角内肢第3节较细,两侧略凹凸不平,其末端具5个脊状齿并呈扇形排列,第3节背缘近中央处具1根长的刚毛,刚毛两侧具若干短刺.