海洋围隔生态系中无机氮对浮游植物演替的影响

本文评述了１９９２年秋冬季在厦门进行的一次海洋围隔生态系实验的结果。实验重现了围隔水体连续富营养引发了甲藻赤潮的现象。间歇性的供给无机氮,不会影响浮游植物演替的顺序,但会导致甲藻赤潮出现时间长短和优势种的差异。实验结果还表明,演替过程对甲藻赤潮的形成起着重要的作用。而不同种属甲藻的生活习性和它们的自养能力使它们的生存能力存在差异。这是形成甲藻赤潮优势种的一个主要因素。甲藻赤潮的发生并不完全依靠水体中营养盐浓度的大小。     

初析赤潮成因研究的围隔实验结果Ⅱ.浮游植物群落演替与甲藻赤潮

探讨了甲藻赤潮与浮游植物演替的关系．多次国隔生态系实验结果表明,在水体相对稳定的生态系中,富营养后总是先发生硅藻的水华或赤潮．随后浮游植物会演替成占优势的甲藻,甚至形成甲藻赤潮．维生素Ｂ（１２）的异常增多可能加速这种演替的进程．但这种稳定水体若受到扰动,将干扰演替,使硅藻水华持续不断地发展,阻碍甲藻形成优势．这可以防止甲藻赤潮的生成．     

东海两种赤潮生物种间竞争的围隔实验

1998年5月和2002年5月在东海赤潮高发区进行了两次添加营养盐诱发赤潮的围隔实验,结果表明,1998年5月实验开始时,具齿原甲藻和中肋骨条藻分别占群落总量的85％和11％,对照围隔中,具齿原甲藻一直处于优势,高峰时所占比例接近99％．加磷围隔中,中肋骨条藻显示出很强的竞争能力,第五天的数量与具齿原甲藻相等．2002年5月用4个围隔装置进行实验,在不同营养状况下两个种的增殖速率不同,营养盐浓度高的围隔中,中肋骨条藻的增殖速率比具齿原甲藻快得多,在营养盐限制条件下,具齿原甲藻比中肋骨条藻存活的要好。表明在营养盐丰富情况下,中肋骨条藻以其快速的繁殖在竞争中取得优势地位,导致中肋骨条藻形成的赤潮持续时间较短,消亡也快,而具齿原甲藻赤潮形成期较长,但在营养盐很低的情况下,还能维持较长时问．     

低盐度围隔调控系统中浮游植物群落的组成

通过池塘陆基围隔实验,对凡纳滨对虾低盐度(2‰～6‰)调控养殖系统中的浮游植物群落与动态进行了研究。结果表明：低盐度调控实验围隔中共发现浮游植物7门58属86种,其中绿藻50种(丰富度为58.1%)、蓝藻18种(20.9%)、硅藻9种(10.5%)、裸藻4种(4.7%)及隐藻3种(3.5%);主要优势种有美丽胶网藻、狭形纤维藻、栅藻,铜绿微囊藻、拟柱胞藻、梅尼小环藻及尖尾蓝隐藻等;早期优势种多更替快,以绿藻为主,中后期蓝藻占优势,60%围隔以铜绿微囊藻为主要优势种;优势种的平均优势度达到59.6%。浮游植物密度平均2.97×10⁷ cells·L^-1,Shannon-Wiener多样性指数2.18;施有机肥的围隔浮游植物种类丰富,多样性和密度高,群落稳定,有利于对虾健康养殖;大量施用无机肥,易诱发有害微囊藻爆发。     

围隔生态系内浮游植物对富磷的响应

在长江口外应用围隔生态系实验方法,研究了富磷与浮游植物生物量的相关性以及浮游植物对磷吸收的种间竞争。结果表明,可溶性磷(主要是PO     

石油分散剂BP-1100X对海洋围隔生态系的影响研究

在分散剂作用下,围隔水体中浮游动物种群数量明显减少,浮游植物因捕食压力不大而诱发“赤潮”,分散的原渍在围隔水体中的生态效应变得不明显,细菌生物量和生产力在实验前期比对照组高,后期则随原油降解而波动,这表明微生物积极参与了原油的降解活动,实验揭示,由于添加物的毒性作用促成的生态系的不平衡,也可最终导致“赤潮”发生。     

石油分散剂BP-1100X对海洋围隔生态系的影响研究

在分散剂作用下,围隔水体中浮游动物种群数量明显减少,浮游植物因捕食压力不大而诱发“赤潮”.分散的原油在围隔水体中的生态效应变得不明显,细菌生物量和生产力在实验前期比对照组高,后期则随原油降解而波动,这表明微生物积极参与了原油的降解活动。实验揭示,由于添加物的毒性作用促成的生态系的不平衡,也可最终导致“赤潮”发生。     

对虾综合养殖围隔中浮游细菌生产力的研究

用5个养虾实验围隔研究了对虾综合养殖生态系浮游细菌的生产力。结果表明,生产量(μgC/L·d)变动在90～909之间,平均为292±141。对虾-罗非鱼-缢蛏混养及对虾-扇贝混养生态系细菌生产量相对稳定;对虾单养及对虾-缢蛏、对虾-罗非鱼混养生态系细菌生产量却变化较大。细菌生产量与水温、细菌生物量及浮游生物群落呼吸量均呈现显著相关性。细菌的日P/B系数变化在0.22～1.67(d-1)之间,平均为0.93±0.37(d-1)。细菌生产量与浮游植物毛生产量比值平均为0.15。     

青岛奥运帆船赛区理化、生物要素现状及富营养化诱发赤潮的围隔实验

于 2 0 0 1年 8月和 9月对青岛 2 0 0 8年奥运会帆船比赛海域进行了理化、生物等要素的综合调查 ,并利用围隔生态实验手段 ,在太平湾进行了营养盐与赤潮的关系研究。结果显示 ,本海域水质良好 ,基本符合一类海水水质标准 ,仅有个别站位出现某种污染物超标现象 ,如 8月份麦岛附近海域氨氮和无机磷超标 ,石油烃 8月份在浮山湾东侧北海船厂附近超出一类海水水质标准。该水域的叶绿素 a含量较低 ,平均 0 .4 2 m g· m- 3,总的分布状况是太平湾西侧的海域较高。初级生产力 8月高于 9月 ,分别为 179.0 mg C m- 2· d- 1和 114 .0 mg C m- 2· d- 1。浮游植物以硅藻中的中肋骨条藻、奇异菱形藻、旋链角刺藻和塔形冠盖藻为主 ,其细胞数量 8月明显高于 9月 ,分别为 4 5 7.2 6× 10 4 m- 3和 16 .38× 10 4 m- 3,数量密集中心在调查区西部。浮游动物生物量 8月比 9月高近 10倍 ,分别为 2 39.1m g· m- 3和 2 4 .7mg· m- 3,强壮箭虫在生物量中起主要作用 ,生物量和个体数量的分布与浮游植物基本相反。加营养盐的围隔实验表明 ,加硅会导致海链藻、短弯角藻、丹麦细柱藻和中肋骨条藻中的任何一种赤潮 ,硅成为该海域的主要限制因子。     

Polarity and apical dominance in Fucus vesiculosus

In Fucus vesiculosus L., culture experiments have illustrated that within 2 mm of the apical cell, the origin of new meristems is inhibited. Further behind the apex, the influence of apical dominance gradually diminishes and beyond about 2 cm its effect is negligible. Polarity, which is so marked in the young plant, is not obvious in older tissues. There is no morphological difference between the branches produced from both cut surfaces of a segment of thallus. But, particularly in young tissue, there is a greater potential for regeneration from what is morphologically the upper end of a segment.     

Glucose transport and metabolism in Gymnodinium breve

Florida's red tide organism, Gymnodinium breve, utilized exogenous glucose in the light for the synthesis of cellular components. Glucose was not taken up in the dark. Kinetic parameters for glucose uptake include a K_FD of 11 μM and a V_max of 1 × 10^?10 mol of glucose taken up/mg cellular protein/hr. Glucose uptake was competitively inhibited by phloridzin (K_i = 40 μM), mannose (K_i = 12O μM), and 2-deoxy-d-glucose (K_i = 190 μM) and non-competitively inhibited by galactose (K_i = 125 μM). Kinetics and inhibition of glucose uptake are consistent with a facilitated diffusion transport system.     

Virus-like Particles Suppress Growth of the Red-Tide-Forming Marine Dinoflagellate <Emphasis Type="Underline">Gymnodinium mikimotoi</Emphasis>

We isolated 2 virus-like agents that suppressed growth of Gymnodinium mikimotoi from coastal waters of the Uwa Sea, Japan. The agents found in the flagellate cells, named GM6 and GM7, were filterable in a 0.22-lm-pore filter with approximately 100-nm shapes. Electron microscopic observation showed the presence of virus-like particles in severely damaged G. mikimotoi cells infected by GM6. The growth-suppression activity of the agents (GM6 or GM7) was lost by heating at 50°C, with treatments of DNase and protease, and filtration through a 0.05-lm filter. Our results suggest that the agents are DNA viruses infectious to and virulent for G. mikimotoi. This is the first report of a virus-like agent specific to G. mikimotoi.     

中国赤潮的发生趋势和研究进展

通过对中国沿海赤潮发生历史的回顾以及主要赤潮事件的分析,阐明了中国沿海赤潮发生所呈现的趋势,即频率增加,规模扩大,新的赤潮藻种不断出现,有毒赤潮种比例上升,以及有害赤潮危害程度日益增加,且初步分析了赤潮频发的内因和外因,综述了我国科学家在赤潮生消过程监测,赤潮灌的培养生物学和分类学,赤潮藻类的营养动力学及生理生态学特性,赤潮藻类的生活史,赤潮藻类毒素,赤潮的模型和赤潮防治及国际合作等方面工作的进展,指出了研究还存在的不足之处,并对未来赤潮研究和管理提出了建议。     

Management of permanent set-aside on arable land in Sweden

1. Set-aside fields have been an important element of the European agricultural landscape since the introduction of the set-aside scheme by the European Community. However, countries in the European Community differ in their rules for managing set-aside owing to different priorities.
2. In Sweden, a major goal is to reduce the total use of agricultural pesticides, consequently their use is prohibited in set-aside. The options for weed control are therefore cutting and/or the use of a cover crop.
3. In this study, we describe the course of succession following the abandonment of farmland managed in different ways. The floristic composition was followed over a 10-year period. Temporal trends in community development are described.
4. The experiment began in 1975 on farmland at six localities, distributed from southern to northern Sweden. The management treatments involving the application of fertilizers and cutting were applied to plots sown with a cover crop and to plots in which the succession started from bare ground.
5. We found that competitive interactions between species largely determined the successional course in our study. The competitive success of species was related to the management practices applied but there were also interactions between management and site conditions.
6. We propose that natural succession can be recommended on poor sites in combination with cutting, mainly to prevent the invasion of woody species. On fertile sites a cover crop should be used to suppress perennial weeds, and cutting is recommended mainly to increase species diversity.     

Sexual differences in natal dispersal and philopatry of the grey-sided vole

The natal dispersal distance of the grey-sided vole,Clethrionomys rufocanus (Sundevall), was measured in a large outdoor enclosure (2.1 ha) in Hokkaido, Japan. Voles in about half of the enclosure (1 ha) were fed. Distance from the natal site to the site of reproduction was significantly greater in males (64.9 m) than in females (35.3 m). In males, 24.8% settled within one home range length of their natal site and 49.6% settled further than two range lengths from their natal site. In femles, the respective percentages were reversed: 51.2% and 22.0%. The timing of large movements (≥50 m) was related to body mass in both sexes. The population density was always higher on the fed grid than on the control grid, which resulted in the frequency of large movements being greater on the fed grid that on the control grid. Thus, the percentage of voles performing a large movement was not different between the grids in both sexes.     

浮游动物摄食在赤潮生消过程中的作用

浮游动物摄食在赤潮生消过程中起相当重要的作用。由于摄食过程的复杂性和生物物种与个体行为存在的多样性 ,使得赤潮过程中浮游动物的摄食研究具有相当难度。从浮游动物的摄食类型和习性、浮游动物摄食率测定、浮游动物选择性摄食对赤潮群落演替发展方向、浮游动物摄食在有毒微藻赤潮中的作用、浮游动物摄食在中国赤潮研究中的关键科学问题等几个方面探讨了浮游动物摄食对赤潮生物种群动力学的影响 ,为理解和治理赤潮提供科学依据