The inhibitory degree between Skeletonema costatum and dinoflagllate Prorocentrum donghaiense at different concentrations of phosphate and nitrate/phosphate ratios     

Jing Cao  Jiangtao Wang 《中国海洋大学学报(英文版)》2012,11(2):153-158

Interactions between Skeletonema costatum (S. costatum) and Prorocentrum donghaiense (P. donghaiiense) were inves-tigated using bi-algal cultures at different concentrations of phosphate (PO4-P) and nitrate/phosphate (N/P) ratios. Experiments were conducted under P-limited conditions and the Lotka-Volterra mathematical model was used to simulate the growth of S. costatum and P. donghaiense in the bi-algal cultures. Both of these two species were inhibited significantly in bi-algal culture. The results of the simulation showed that the inhibitory degree of S. costaum by P. donghaiense was high when the concentration of PO4-P was low (0.1μmolL-1/2 d), but that of P. donghaiense by S. costaum was high with increased PO4-P supply (0.6μmolL-1/2 d). At low concen-tration of PO4-P (0.1μmolL-1/2 d), or high concentration of PO4-P (0.6μmolL-1/2 d) with high N/P ratio (160), the interactions be-tween S. costatum and P. donghaiense were dependent on the initial cell densities of both species. At high concentration of PO4-P (0.6μmolL-1/2 d) with low N/P ratio (25 or 80), S. costatum exhibited a survival strategy superior to that of P. donghaiense. The de-gree of inhibition of P. donghaiense by S. costaum increased with elevated N/P ratio when the medium was supplemented with con-centration 0.1μmolL-1/2 d of PO4-P. The degree of inhibition to P. donghaiense by S. costaum increased with elevated N/P ratio at low concentration of PO4-P (0.1 μmolL-1/2 d). This trend was conversed at high concentration of PO4-P (0.6μmolL-1/2 d). However, the degree of inhibition of S. costaum by P. donghaiense increased with the increased N/P ratio at different PO4-P concentrations (0.1μmolL-1/2 d and 0.6μmolL-1/2 d). These results suggested that both phosphate concentration and N/P ratio affected the competition between S. costaum and P. donghaiense: P. donghaiense is more competitive in environments with low phosphate or high N/P ratio and the influence of N/P ratio on the competition was more significant with lower phosphate concentration.  相似文献   

植物护理效应研究综述   总被引：2，自引：0，他引：2  

杨龙  刘楠  王俊 《热带地理》2012,32(3):321-330

植物护理效应是指护理植物在其自身冠幅下辅助目标植物生长发育的现象.近年来,植物护理效应被应用于世界范围内多数的退化生态系统的修复与重建.文章综述了当前植物护理效应的主流研究内容主要为护理植物的确定、影响其效应的因素、形成其效应的原因与机理以及护理、竞争及胁迫梯度假说,归纳了样方调查、种子萌发实验、幼苗栽植实验等研究方法,总结了其与生态位、系统发育、全球变化等相关生态学概念的关系,指出未来对植物护理效应的研究不应仅仅局限于中观尺度上,在微观尺度上(目标植物对护理效应的生态适应性的激素效应与分子机制)和宏观尺  相似文献   

First report of the genus Lysippe Malmgren, 1866 (Polychaeta: Ampharetidae) from Chinese waters   总被引：2，自引：0，他引：2  

隋吉星  李新正 《中国海洋湖沼学报》2013,31(4):846-849

The ampharetid genus Lysippe Malmgren, 1866 is reported for the first time from Chinese waters. The identification was based on material deposited in the Marine Biological Museum of the Chinese Academy of Sciences (Qingdao). A new species, Lysippe trichobranchia sp. nov. is described. The new species is widely distributed in shallow waters of the Bohai Gulf, the Yellow Sea and the East China Sea at depths of 10-40 m.  相似文献   

A new record of Cleantioides emarginata Kwon & Kim, 1992 (Crustacea, Isopoda, Valvifera) from Changjiang River estuary, China     

刘文亮 《中国海洋湖沼学报》2013,31(3):625-631

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Vegetation and Community Changes of Elm （Ulmuspumila） Woodlands in Northeastern China in 1983-2011     

Li Liu  He Wang  Changcun Lin  Deli Wang 《中国地理科学(英文版)》2013,23(3):321-330

Elm (Ulmus pumila), widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental significance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors affected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth (small, short and twisted). The mean age of the elm was 29 ± 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups: Group I including the undisturbed sample stands of 83UE (undisturbed elm woodland in 1983) and 11UE (undisturbed elm woodland in 2011); Group II including sample stands of PE (elm woodland disturbed by plowing); Group III including samples stands of GE (elm woodland disturbed by grazing). The results indicate that the long time disturbance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland.  相似文献   

Composition and distribution of diatom assemblages in the surface sediments of the Bering Sea     

SHAO Lixia  LIN Rongcheng  GAO Yahui  HUANG Dingyong 《极地研究(英文版)》2013,(3):167-174

Diatoms collected from the top 1 cm of the surface sediment layer at seven Bering Sea stations during the Fourth Chi- nese National Arctic Research Expedition （4th CH1NARE-Arctic） in 2010 were studied. In total, 101 taxa belonging to 38 genera were found. The species were divided into four groups： eurythermal species, boreal-temperate species, polar species, and sea-ice species. The diatom assemblages at the stations in the southwestern basin area were primarily composed of boreal-temperate species, such as Neodenticula seminae, Thalassiosira trifulta, Rhizosolenia hebetata f. hiemalis, and Actinocyclus curvatulus. The northeastern shelf stations were dominated by polar species, including Fragilariopsis oceanica, Thalassiosira antarctica spora, Thalassiosira nordensldoeldii, and Thalassiosira hyalina. The overall abundance was highest at the basin stations with 3.7 ×10^6 cells·g^-1 of wet sediment, whereas the eastern shelf stations had the lowest abundance of 0.7×10^6 cells·g^-1 of wet sediment （excluding the resting spores of Chaetoceros spp.）. The relationship between the distribution of the surface sediment diatom assemblages and the environment is discussed.  相似文献   

古尔班通古特沙漠植被与环境关系分析   总被引：2，自引：0，他引：2  

钱亦兵  吴兆宁  赵锐锋  张立运 《地理学报(英文版)》2008,18(4):400-414

The Gurbantunggut Desert is the largest stable and semi-stable sand desert in China, yet few data exist on vegetation pattern and species-environment relationships for these diverse desert landscapes. The sand dunes of the survey area are mainly of the longi- tudinal form from north to south, but checkerboard-shaped and honeycomb-shaped forms are also present, with the height of 10-50 m. We measured vegetation and soil data on north-south transects and compared them with vegetation and soil data on east-west transects. Analysis revealed that the varying trend and strength of the species diversity, dominance and cover of the plant communities in the longitudinal and transverse directions across the landscape are significantly different. The results of CCA ordination show that the microhabitats of soil organic matter （OM）, soil salts （TS）, sorting index （ σ ）, topsoil water-content （SM） and pH relate to the differences in vegetation observed as differences in species assemblage from salt-intolerant ephemerals, micro-subshrubs and subshrubs to salt-tolerant shrubs and micro-arbors. The terrain （alt.） and soil texture （the contents of Mz and Ф 1） affect the spatial differentiation of many species. However, this spatial differentiation is not so marked on transects running longitudinally with the landscape, in the same direction as the dunes. The species of the desert vegetation have formed three assemblages under the action of habitat gradients, relating to three sections running transversely across the landscape, at right angles to the direction of the dune crests. In the mid-east section of the study area the topography is higher, with sand-lands or dune-slopes with coarse particles. Here the dominant vegetation comprises shrubs and subshrubs of Seriphidium santofium and Ephedra distachya, with large numbers of ephemeral and ephemeroid plants of Senecio subdentatus, and Carex physodes in spring and summer. On the soil of the dune-slopes in the mid-west of the study area, with coarse partic  相似文献   

洪河自然保护区湿地主要植被类型物种多样性与表层土壤性质的相关性研究   总被引：1，自引：0，他引：1  

娄彦景  赵魁义 《湿地科学》2008,6(1):45-50

对洪河湿地主要植被类型物种多样性特征、土壤性质特征及二者之间的相互关系进行了研究。结果表明:按沼泽—沼泽化草甸—湿草甸—灌丛草甸—岛状林的序列,物种丰富度呈逐渐增加的变化格局,物种多样性、均匀度呈先下降后上升的格局,优势度呈先上升后下降的格局;而土壤性质特征则呈不规则变化格局。植物物种多样性与土壤性质之间只有均匀度与速效氮之间存在着极显著正相关,其他均无显著相关。这说明在洪河湿地,土壤性质不是决定上述序列的植被类型的物种多样性的主要因素,而土壤速效氮含量是影响物种均匀度的关键因素,同时,对其他物种多样性特征也有一定影响。  相似文献   

塔里木河中游天然植物群落结构与数量特征分析   总被引：2，自引：1，他引：1  

刘宏霞  陈亚宁  李卫红  闫培锋 《干旱区地理》2008,31(1):109-116

运用典型样地法,对塔里木河中游30个天然植被样地的群落结构和数量特征做了调查分析。结果表明:(1)塔里木河中游沙吉力克、沙子河、乌斯满、阿其河、铁依孜五个断面的天然植物隶属11科,20属,22种。(2)塔里木河中游植物群落结构可分三层,即乔木层、灌木层与草本层,但这种乔、灌、草的三层现象不明显。生境条件差,植物对环境利用不充分。(3)荒漠植物群落物种多样性水平较低,群落结构简单,物种组成单一。从多样性指数的数量特征来看,Simpson多样性指数的变化范围为0.47~0.609,Shannon-Wiener指数变化范围0.849~1.302;Menhinick丰富度指数的变化范围为2.309~3.175,Margalef 2.731~5.461;JSW均匀度指数的变化范围为0.6~0.778,JSI指数的变化范围0.633~0.805。五个断面盖度的变化范围是0.259~0.563。  相似文献   

Post‐planktqnic stages of pinnotheres novaezelandiae filhol, 1886 (Brachyura: Pinnqtheridae)     

J. B. Jones 《新西兰海洋与淡水研究杂志》2013,47(1):145-158

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