Present status and changes of the phytoplankton community after invasion of Neosalanx taihuensis since 1982 in a deep oligotrophic plateau lake, Lake Fuxian in the subtropical China

Phytoplankton assemblages in the subtrophical oligotrophic Lake Fuxian, the second deepest lake in China, were investigated monthly from September 2002 to August 2003. A total of 113 species belonging to seven phyla were identified, among them, a filamentous green alga, Mougeotia sp., dominated almost throughout the study period and comprised most of the total phytoplankton biomass. Mougeotia sp. has made a substantial development during the past decades: it was absent in 1957, only occasionally present in 1983, increased substantially in 1993, and became predominant in 2002-2003. It is likely that natural invasion of the Taihu Lake noodlefish (Neosalanx taihuensis) has led to a change of dominant herbivorous zooplankton from small to large calanoid, which has increased grazing pressure on small edible algae, and thus has indirectly favored the development of the inedible filamentous Mougeotia sp.

CAPRICE源磁场改进和冷阴极电子枪的应用及激光离子源的初步实验

在本文第一部分主要描述了ECR离子源的现状、发展和重要物理机制，着重介绍了CAPRICE 10GHz ECR源磁场构形的改进，使其Ar~(8+)离子束流增强了约20%且注入级和引出级线包的电功率消耗分别降低10%和20%。当把冷阴极电子松应用于CAPRICE源中时，Ar~(8+)离子束流入140μA增加到240μA微波功率也有明显降低。所有这些结果都表明ECR源对于气体或已产生的固体蒸气是一个很好的离化装置，为了将激光技术应用于ECR源中来产生固态元素离子，我们又开展了激光离子源的研究.在第二部分则介绍了激光源的现状、发展和激光产生等离子体的物理过程，并详细研究了激光参数及掺气对激光等离子体的影响，在实验中，当用磁镜场或磁Cusp场约束激光等离子体时，离子总束流峰值增加了约5倍；而在激光产生等离子体后附加上高频再游离装置时，同样也使总束流峰值从460μA增至1.4mA，这些低电荷态离子数量足以使ECR源产生需要的高电荷态离子输出

Ecological environment changes in Daya Bay, China, from 1982 to 2004

Data collected from 12 marine monitoring stations in Daya Bay from 1982 to 2004 reveal a substantial change in the ecological environment of this region. The average N/P ratio increased from 1.377 in 1985 to 49.09 in 2004. Algal species changed from 159 species of 46 genera in 1982 to 126 species of 44 genera in 2004. Major zooplankton species went from 46 species in 1983 to 36 species in 2004. The annual mean biomass of benthic animals was recorded at 123.10 gm(2) in 1982 and 126.68 g m(2) in 2004. Mean biomass and species of benthic animals near nuclear power plants ranged froth 317.9 g m(2) in 1991 to 45.24 g m(2) in 2004 and from 250 species in 1991 to 177 species in 2004. A total of 12-19 species of hermatypic corals and 13 species of mangrove plants were observed in Daya Bay from 1984 to 2002. 2008 Elsevier Ltd. All rights reserved.

A new species and two new record species of genus Allokepon Markham, 1982 (Isopoda : Epicaridea : Bopyridae) from China

Descriptions of a new species and two new records of species of the genus Allokepon Markham, 1982 from Chinese waters are presented. The host species were portunid crabs. Allokepon hendersoni (Giard & Bonnier 1887) was found infesting Charybdis bimaculata (Miers), A. monodi (Bourdon, 1967) infesting Portunus pelagicus (L), Portunus trituberculatus ( Miers), and Thalamita sp. and A. longicauda n. sp. infesting Portunus pulchricristatus (Gorden). Three of the host species were recorded for the first time harboring isopod parasites, and the male of A. monodi is presented. Allokepon longicauda n. sp. is distinguished from the other four species found in China by the long slender uropods of females.