我国五大湖日本沼虾线粒体COI基因部分片段序列比较

对我国五大湖日本沼虾100个野生个体的线粒体细胞色素氧化酶亚基I（COI）部分序列进行了测定和分析，经比对获得578bp核苷酸片段，发现49个变异位点，得到35个单倍型，包括7个共享单倍型，各群体都具有较好的单倍型多态性和核苷酸多态性，其中鄱阳湖群体遗传多样性相对最高。AMOVA分析表明，五群体间总遗传分化系数F_st＝0.31873 （P<0.05）， 群体间具有较高的遗传分化。MEGA3.1软件计算五群体的Kimura 2-paramter遗传距离，洞庭湖群体和巢湖群体之间的遗传距离最远为0.0191，巢湖群体和洪泽湖群体之间的遗传距离最近为0.0051。以同属胖掌沼虾（Macrobrachium inflatum）为外群分别构建了NJ和UPGMA系统树，结果显示洞庭湖和鄱阳湖为一族群，太湖、巢湖和洪泽湖为一族群。     

Temperature dependent growth and yield of pikeperch, Sander lucioperca, in Finnish lakes

Abstract  A non-linear growth model was used to evaluate the effects of temperature and age on annual length increments of pikeperch, Sander lucioperca (L.), in seven lakes in Finland. Length increments were derived by back-calculation using the Fraser–Lee method. Annual length increments increased from age 1 to age 3 and then decreased, while at the same time length increments and air temperature had positive correlation until age 12. Age- and size-structured yield per recruit models were used in two lakes to evaluate the effects of temperature and gillnet mesh size on pikeperch yield. In these two lakes maximum yield could be obtained with 60 and 70 mm (bar length) gill nets. In the second lake, as typically in Finland, 45–50 mm gill nets are the most frequently used. The use of larger mesh size gill nets would increase pikeperch yield from 685 to 1000 g per recruit based on the present mean temperature. In both lakes increase in temperatures would increase yield if mesh size is simultaneously increased. Higher pikeperch yield can be expected in the future because of climate warming.     

巴彦淖尔市农垦系统中小湖泊渔业资源调查

2004年4月至2005年1月,对内蒙古自治区巴彦淖尔市农垦系统13个大中水面渔业资源进行了周年调查。文章对除乌梁素海以外其他12个中小湖泊调查结果进行总结分析。这些湖泊多数为草型浅水湖泊,盐碱含量较高,如纳林湖、姚军海子、白条海子总含盐量平均在3.5‰以上,个别水体如纳林湖、姚军海子总碱度平均超出15mol/l。大多水体有效氮含量较高,但有效磷不足,氮、磷比例失调。除大汉海子、刘铁海子和南一队海子的浮游生物含量较高外,其余9个湖泊浮游生物含量均较低,水质清瘦,鱼产量较低。并在调查基础上提出了综合开发利用渔业资源的建议。     

Monitoring fish stocks in relation to acidification in Norwegian watersheds

The Norwegian Monitoring Programme for Long-Range Transported Air Pollutants started in 1980. The biological part of this programme includes besides invertebrate studies in streams, (i) fish community status in lakes by means of interviews, test-fishing in lakes by using standard gill-net series, recruitment studies of brown trout in inland streams, and juvenile stock assess and monitoring of fish kills in salmon rivers. Damaged fish stocks are recognized within a land area of 51,500 km² in southern Norway and 30 km² in northern Norway. At least 6,000 lake-dwelling fish stocks have either been lost or are at various stages of reduction. Brown trout (Salmo trutta) is the most widespread and abundant species of fish in Norwegian watersheds, and is also most severe affected by acidification. More recently, there are some indications of an increase in the abundance of brown trout in some areas. However, analysis of age structure in lakes, and fry densities in streams in such areas revealed large annual variations in recruitment rate, which indicates unstable water chemical conditions. Atlantic salmon (Salmo salar) is virtually extinct in 25 rivers in southernmost, southwestern and western Norway.     

Above- and belowground ecosystem biomass and carbon pools in an age-sequence of temperate pine plantation forests

We assessed the successional development of above- and belowground ecosystem biomass and carbon (C) pools in an age-sequence of four White pine (Pinus strobus L.) plantation stands (2-, 15-, 30-, and 65-years-old) in Southern Ontario, Canada. Biomass and C stocks of above- and belowground live and dead tree biomass, understorey and forest ground vegetation, forest floor C (LFH-layer), and woody debris were determined from plot-level inventories and destructive tree sampling. Small root biomass (<5 mm) and mineral soil C stocks were estimated from soil cores. Aboveground tree biomass became the major ecosystem C pool with increasing age, reaching 0.5, 66, 92, and 176 t ha⁻¹ in the 2-, 15-, 30-, and 65-year-old stands, respectively. Tree root biomass increased from 0.1 to 10, 18, 38 t ha⁻¹ in the 2-, 15-, 30-, and 65-year-old stands, respectively, contributing considerably to the total ecosystem C in the three older stands. Forest floor C was 0.8, 7.5, 5.4, and 12.1 t C ha⁻¹ in the 2-, 15-, 30-, and 65-year-old stands, respectively, indicating an increase during the first two decades, but no further age-effect during the later growth phase. Mineral soil C was age-independent with 37.2, 33.9, 39.1, and 36.7 t C ha⁻¹ in the 2-, 15-, 30-, and 65-year-old stands, respectively. Aboveground ecosystem C increased with age from 3 to 40, 52, and 100 t C ha⁻¹ in the 2-, 15-, 30-, and 65-year-old stands, respectively, due to an increase in aboveground tree biomass. Belowground ecosystem C remained similiar in the early decades after establishment with 37, 39, and 39 t C ha⁻¹ in the 2-, 15-, and 30-year-old stands, but increased to 56 t C ha⁻¹ in the 65-year-old stand due to an increase in root biomass. The difference in total ecosystem C between the 2- and 65-year-old stand was 116 t C ha⁻¹. Our results highlight the importance of considering the successional development of forest ecosystem C pools, when estimating C sink potentials over their complete life cycle.     

Combined effects of best management practices on water quality in oxbow lakes from agricultural watersheds

Water quality conditions in three oxbow lakes were examined before and after best management practices (BMPs) implementation within the Mississippi Delta. Experimental design called for the development of structural and cultural treatments to reduce sediment and associated pollutants entering watershed oxbow lakes. Three watersheds were selected and developed with different levels of BMPs. Changes in lake water quality were used as measures of management success. Analyses of water quality data prior to the implementation of BMPs suggested the lakes were stressed and ecologically damaged due to excessive sediment inflow. Significant improvements in water quality were observed with the use of cultural and structural BMPs. Sediments decreased 34–59%, while Secchi visibility and chlorophyll generally increased. The most dramatic improvements in water quality occurred in the two watersheds that featured cultural practices and combinations of cultural and structural practices. Reducing suspended sediment concentrations in these oxbow lakes favored phytoplankton production resulting in increased chlorophyll concentrations and higher concentrations of dissolved oxygen. Cultural BMPs, more so than structural BMPs, play a vital role in improving lake water quality, and are needed in addition to structural measures to ensure improved water quality in oxbow lakes receiving agricultural runoff.     

中国五大湖三角帆蚌群体遗传多样性的RAPD分析

用OPJ和OPM两组40条10碱基随机引物,对中国五大湖三角帆蚌地理群体及诸暨养殖蚌进行了随机扩增多态性DNA(RAPD)分析,其中12个引物的扩增结果具有丰富的群体多态性,多态率为55.6%～80%。群体内遗传相似度大小依次为:鄱阳湖(0.8889),太湖(0.8694),洞庭湖(0.8111),诸暨(0.7746),洪泽湖(0.7348),巢湖(0.7185)。依据群体间遗传距离指数及分子系统树,表明洞庭湖群体和洪泽湖群体亲缘关系最近,鄱阳湖群体则与巢湖群体的亲缘关系最近,并且诸暨人工养殖群体与鄱阳湖和巢湖的群体比较接近。     

不同湖泊养殖中华绒螯蟹脂肪酸组成比较分析

为探明在不同生态环境条件下养殖中华绒螯蟹的品质,采用气相色谱法对江苏境内八大湖泊养殖品牌河蟹可食部分脂肪酸组成进行比较分析,结果表明,八大湖泊养殖中华绒鳌蟹可食部分含18种脂肪酸,其中饱和脂肪酸(SFA)5种,单烯酸(MUFA)3种,多烯酸(PUFA)10种。雌蟹SFA含量,以大纵湖蟹最高,与阳澄湖蟹、洪泽湖蟹差异达显著水平(p<0.05);雄蟹SFA含量,以长荡湖蟹最高,与阳澄湖蟹差异达极显著水平(p<0.01)。MUFA含量,雌蟹以大纵湖蟹最高,与长荡湖蟹、阳澄湖蟹、洪泽湖蟹差异达显著水平(p<0.05);雄蟹以大纵湖蟹最高,与阳澄湖蟹、洪泽湖蟹差异达显著水平(p<0.05)。PUFA含量,雌蟹以固城湖蟹最高,与洪泽湖蟹差异达极显著水平(p<0.01);雄蟹以固城湖蟹最高,与阳澄湖蟹差异达极显著水平(p<0.01)。     

云南高原湖泊地区水资源脆弱性评价研究

针对云南高原湖泊独特的生态环境及水资源现状,构建了基于压力状态响应模型的高原湖泊水资源脆弱性评价指标体系。以湖泊区域典型代表玉溪市近30年水资源变化情况为案例,运用集对评价法对高原湖泊水资源脆弱性进行分析评价。结果表明：该区域2005-2007年水资源脆弱性程度为中度脆弱,并呈现一定的恶化趋势,表明目前高原湖泊的水资源承载能力与区域经济、社会发展和生态环境保护方面存在显著错位情况,亟待加强水环境保护与综合整治。