松花湖富营养化现状及其影响因素分析

通过2002年和2003年对东北地区松花湖水体富营养化状况进行调查和采样分析，对大量数据的多元相关分析和多元逐步回归分析、AGP试验和利用综合营养状态指数法进行评价。结果表明：松花湖处在中营养和轻度富营养状态；总磷是限制水体富营养化的主要因子之一。水体中变温层的形成，限制了上、下层湖水的混合，对下层水体中的溶解氧、无机氮和可溶性磷酸盐产生影响，随着变温层的消失，下层内的营养物质转移到湖上层，为藻类的繁殖提供条件。     

气象条件对滇池水华分布的影响

使用MODIS卫星资料,利用假彩色合成法和归一化植被指数法对滇池蓝藻水华进行监测,得到滇池水华的分布特征是：初现于5月,7月最盛,5—10月均有分布,盛时滇池水华分布区域直至南部海口一线。滇池水华分布总体北部最多,湖岸高于中心湖区,西岸高于东岸和南岸。在营养盐条件满足的条件下,高温对水华有促进作用,但不是决定因素。充足的日照是水华形成的必要条件。降水通过改变水温及日照对水华有抑制作用。小风（小于3 m/s）利于水华形成,大风对水华尤其是稀薄水华分布影响较大。气象条件通过相互影响,共同作用对水华产生影响。     

长江口及其邻近海域有害藻华的发生情况、危害效应与演变趋势

长江口及其邻近海域是我国近海有害藻华高发区之一。自2000年以来,由东海原甲藻(Prorocentrum donghaiense)、米氏凯伦藻(Karenia mikimotoi)和亚历山大藻(Alexandrium spp.)等甲藻形成的大规模有害藻华连年暴发,对海水养殖业、人类健康和生态安全构成了严重威胁。以往调查和研究工作表明,长江口及其邻近海域藻华优势类群近年来已由硅藻逐渐转变为甲藻,同时,有害藻华原因种也表现出明显的年际变异特征和有毒有害藻种增多的态势,亟待解析其演变机理、趋势和驱动因素。长江口及其邻近海域受长江径流影响,富营养化问题突出,是大规模有害藻华形成的重要原因。同时,该海域也受到来自台湾东北部黑潮分支的影响,但对其与有害藻华的关系所知甚少。在中国科学院战略性先导科技专项"热带西太平洋海洋系统物质能量交换及其影响"支持下,针对这一问题开展了较为系统的调查和研究工作,本文对研究中得到的科学认识进行了初步总结。结果表明:东海黑潮分支能够到达长江口及其邻近海域赤潮区,影响该海域赤潮生物多样性状况;黑潮分支对长江口及其邻近海域甲藻赤潮发生过程具有重要调控作用;长江冲淡水和黑潮分支的共同作用决定了长江口及其邻近海域有害藻华的发生过程和演变趋势。在现有结果基础上进一步分析和讨论了未来长江口及其邻近海域有害藻华的研究方向,以期为进一步解析有害藻华演变趋势、提升有害藻华的监测和预警能力提供依据。     

近海浮游植物水华动力学和生物气候学研究综述

浮游植物水华作为近海重要的生物过程,其动态变化对生态系统内的能童传递、生产力水平和各生源要素的循环等均有重要影响.随着气候变化对生态系统影响研究的深入,浮游植物水华生物气候学研究已成为当前生物海洋学研究的热点.综述了浮游植物水华的研究历史、研究方法及其发生发展的动力学机制,重点评述了气候变化对浮游植物水华动态的影响及国...     

渤海生态动力过程的模型研究 Ⅱ.营养盐以及叶绿素a的季节变化

利用在本系列研究第一部分中所建立的耦合的生物物理模型,模拟了渤海浮游植物生物量和营养盐含量的年度循环特征.模拟结果显示:藻类的春季水华是由经过一冬积累在水体中的营养盐导致,而水华开始的时间在浅水区明显早于深水区,对此深水区水体层化结构的形成可能起着重要作用;另一方面,河载营养盐与悬起的沉积物所释放的营养盐是诱发夏季水华的共同原因.基于模型结果,我们还发现:渤海的浮游植物动力特性就整体而言依然受无机氮限制,但是在莱州湾,磷限制特性表现得非常明显,这主要是由于每年黄河都要携带大量的无机氮进入海水,从而导致莱州湾营养盐的氮磷比已远远超过16.     

Biological mechanisms driving the seasonal changes in the internal loading of phosphorus in shallow lakes

Because of the obvious importance of P as a nutrient that often accelerates growth of phytoplankton (including toxic cyanobacteria) and therefore worsens water quality, much interest has been devoted to P exchange across the sediment-water interface. Generally, the release mode of P from the sediment differed greatly between shallow and deep lakes, and much of the effort has been focused on iron and oxygen, and also on the relevant environmental factors, for example, turbulence and decomposition, but a large part of the P variation in shallow lakes remains unexplained. This paper reviews experimental and field studies on the mechanisms of P release from the sediment in the shallow temperate (in Europe) and subtropical (in the middle and lower reaches of the Yangtze River in China) lakes, and it is suggested that pH rather than DO might be more important in driving the seasonal dynamics of internal P loading in these shallow lakes, i.e., intense photosynthesis of phytoplankton increases pH of the lake water and thus may increase pH of the surface sediment, leading to enhanced release of P (especially iron-bound P) from the sediment. Based on the selective pump of P (but not N) from the sediment by algal blooms, it is concluded that photosynthesis which is closely related to eutrophication level is the driving force for the seasonal variation of internal P loading in shallow lakes. This is a new finding. Additionally, the selective pump of P from the sediment by algal blooms not only explains satisfactorily why both TP and PO4-P in the hypereutrophic Lake Donghu declined significantly since the mid-1980s when heavy cyanobacterial blooms were eliminated by the nontraditional biomanipulation (massive stocking of the filter-feeding silver and bighead carps), but also explains why TP in European lakes decreased remarkably in the spring clear-water phase with less phytoplankton during the seasonal succession of aquatic communities or when phytoplankton biomass was decreased by traditional biomanipulation. Compared with deep lakes, wax and wane of phytoplankton due to alternations in the ecosystem structure is also able to exert significant influences on the P exchange at the sediment-water interface in shallow lakes. In other words, biological activities are also able to drive P release from sediments, and such a static P release process is especially more prominent in eutrophic shallow lakes with dense phytoplankton.     

Short-term consequences of a benthic cyanobacterial bloom (Lyngbya majuscula Gomont) for fish and penaeid prawns in Moreton Bay (Queensland, Australia)

This study examined the phenology and ecological consequences of a benthic filamentous cyanobacterial bloom (Lyngbya majuscula) in Deception Bay (Moreton Bay, Queensland, Australia). Bloom initiation occurred in mid December 1999 and expanded to encompass an 8 km² area by April 2000. Small fish and penaeid prawns (<25 cm total length) were quantitatively sampled through periods designated as before, during and after the bloom using a combination of pop-netting within mangroves and beam trawling over adjacent seagrass beds. Data on larger-bodied fish were compiled from daily fishing logs provided by local commercial fishers. Changes in dry mass of bloom material caught in nets and changes in water chemistry were also measured. Mean concentrations of ammonia-N in residual water within mangroves were several orders of magnitude higher in the affected area than in the control and dissolved oxygen was markedly lower in affected areas. Across the study area, mean density, live mass and number of species declined during the bloom, with fish assemblages using mangroves showing greater decline than assemblages using seagrasses. Response at the species level was highly variable; generally, epibenthic species showed a more sustained decline than demersals. Mean monthly fish catch was significantly lower in bloom than non-bloom years. This study has also demonstrated that throughout the bloom, the affected area continued to support a highly diverse and abundant fish and prawn assemblage, and probably maintained its function as an important nursery habitat for many species.     

藻类勃发—湖相油源岩形成的一种重要机制

浮游藻类是重要的湖相生油母质，本文以渤海湾盆地济阳坳陷早第三纪湖相生油岩为例，研究了其中藻类（主要是颗石藻和沟鞭藻＿化石的分布特征，并通过与现代水体中藻类生产和沉积作用的比较，探讨了生油湖泊中藻类生产和沉积方式及其对油源岩形成所起的控制作用，结果显示，藻类勃发现象在早第三纪生油湖泊中相当普遍，而且贯穿于各类油源岩的形成过程，这类快速事件性沉积是湖相油源岩形成的一种重要机制。     

太湖蓝藻水华暴发机制与控制对策

湖泊蓝藻水华暴发由于引发水生态系统的灾害和饮用水安全风险而成为国内外研究的热点之一.太湖蓝藻水华暴发原因多样,其中蓝藻自身的特性是水华暴发的内因,太湖的地理、水文和气象特征为蓝藻水华暴发提供了合适的温度和水动力条件,是蓝藻水华暴发的外因,湖泊草-藻型生态系统的转变以及氮、磷营养盐的高负荷输入更利于蓝藻生长,湖泊氮、磷营养盐四重循环是蓝藻水华不断暴发的维持机制,蓝藻水华暴发与氮、磷营养盐浓度之间存在交互作用关系.太湖蓝藻水华的控制应以陆源控源截污为基础,增加湖泊营养盐输出为重点,实现疏堵有机结合,其中恢复水生植被,重建草-藻结合型水生态系统是太湖湖泊生态修复的关键所在.