沿岸海域富营养化与赤潮发生的关系

综述了赤潮的发生与沿岸海域富营养化的关系。近几十年来,人类活动使得天然水体的富营养化进程大大加速。营养负荷的增加与高生物量水华的增多相联系。控制营养输入后,浮游植物生物量或有害藻类水华事件也相应减少。营养的组成与浮游植物的种类组成及水华的形成有密切联系。有机营养对有害藻类水华的促进作用受到关注。营养输入时机影响浮游植物种间竞争的结果,因而对浮游植物的群落演替具有深远影响。由于浮游植物存在生理差异,因而对营养加富的反应因种而异。营养在调控某些有毒藻类的毒素产量方面也发挥着重要作用。此外,营养输入与藻类水华之间存在复杂的间接联系。当然,营养状况并非浮游植物群落演替的唯一决定因素。研究结果提示,控制营养输入、减缓水域富营养化是减少有害藻类水华发生的有效途径,而深入研究典型有害藻类的营养生理对策则为防治并最终消除有害藻类水华提供了理论基础。     

Dilution bioassays: Their application to assessments of nutrient limitation in

Hypereutrophic waters, which are characterized by nutrient inputs exceeding phytoplankton nutrient requirements, are often sites of chronic nuisance algal blooms and associated water quality deterioration problems. In order to restore such systems to acceptable water quality standards, identification of growth-limiting nutrients is of central importance. Conventional nutrient addition bioassay techniques are often ineffective in identifying potentially limiting nutrients, due to persistent nutrient excesses in hypereutrophic systems. Accordingly, we have developed a nutrient dilution bioassay, in which stepwise dilutions of phytoplankton nutrients (nitrogen, phosphorus, iron, trace metals) with a nutrient-free major ion solution are capable of; 1) identifying those nutrients potentially most limiting, and 2) establishing magnitudes of respective nutrient input cutbacks required to bring about nutrient-limited control of phytoplankton growth. In situ deployment of dilution bioassays should help establish criteria governing minimal nutrient inputs required to arrest undesirable impacts of hypereutrophy. We have evaluated the field applicability of dilution bioassays, during a 2 year trial in the periodically hypereutrophic Neuse River, North Carolina.     

Cyanobacterial dominance in lakes

Cyanobacterial dominance in lakes has received much attention in the past because of frequent bloom formation in lakes of higher trophic levels. In this paper, underlying mechanisms of cyanobacterial dominance are analyzed and discussed using both original and literature data from various shallow mixed and deep stratifying lakes from temperate and (sub)tropical regions. Examples include all four ecotypes of cyanobacteria sensu Mur et al. (1993), because their behavior in the water column is entirely different. Colony forming species (Microcystis) are exemplified from the large shallow Tai Hu, China. Data from a shallow urban lake, Alte Donau in Austria are used to characterize well mixed species (Cylindrospermopsis), while stratifying species (Planktothrix) are analyzed from the deep alpine lake Mondsee. Nitrogen fixing species (Aphanizomenon) are typified from a shallow river-run lake in Germany. Factors causing the dominance of one or the other group are often difficult to reveal because several interacting factors are usually involved which are not necessarily the same in different environments. Strategies for restoration, therefore, depend on both the cyanobacterial species involved and the specific causing situation. Some uncertainty about the success of correctives, however, will remain due to the stochastic nature of the events and pathways leading to cyanobacterial blooms. Truly integrated research programs are required to generate predictive models capable of quantifying key variables at appropriate spatial and temporal scales.     

船舶压载水携带外来物种及其对水域生态环境的影响

随着世界航运业的不断发展 ,船舶频繁地来往于世界各地 ,船舶压载水作为一种外来物种传播的有效媒介物 ,使得不同水域的物种得以传播到其他水域。这些物种种类繁多 ,普遍具有适应性较强 ,危害性较大等特点。本文就一些世界范围内广泛传播的典型外来物种进行了列举 ,并对它们的分类、发源地、传入媒介、习性、分布以及由于它们的入侵给当地的生态环境、人类健康、经济带来的不利影响以及当地所采取的一些治理措施等进行了较为详细地阐述。提出控制船舶压载水的排放以及研究较为有效的压载水治理方法是解决压载水携带外来物种入侵性传播的有效途径     

Causes,historical development,effects and future challenges of a common environmental problem: eutrophication

The impact of the presence of us humans as well as our activities to nature has led to over-exploitation of natural resources and to dramatic changes in land-use including the use of artificial fertilizers contributes to the deterioration of the natural environment. The population density, industrial processes and the use of fertilizers are the main causes for the eutrophication of river systems, estuaries and seas. There are several ways to determine the actual nutrient levels back to the 1950s, back to 1900 or even back to 1800. Available data indicate that the natural background concentrations of nutrients (pristine conditions or the period prior to the widespread use of artificial fertilizers and detergents) were dramatically lower than today. Available time series on chemical and biological data collected from different parts of the world show the (sometimes tremendous) increase in nutrient levels and the related productivity. The same time series, however, also show the decreases in values when measures were taken to reduce the nutrient emissions. Investigations of different systems all over the world show that nearly every system responses differently to eutrophication. Especially physical boundary conditions play an important role in the manifestation of the ultimate effect of local eutrophication. Apart from the physical boundary conditions also the transformation and retention of nutrients in estuarine and coastal systems contribute to system specific responses. Depending on all these different conditions, site specific responses with even site specific problems may occur. The challenge of this millennium is to really reach a balance between nature and mankind including its population size. A beneficial step in this discussion is assessing criteria to reduce eutrophication back to a level acceptable to both humans and nature.     

中华哲水蚤(Calanus sinicus)对浮游植物和微型浮游动物的摄食速率估算

2005年4月27日至5月30日在东海有害藻华高发区的6个典型站位采样,结合稀释法实验和Frost的直接计量法研究了中型浮游动物对浮游植物和微型浮游动物群落的现场摄食速率,并对中华哲水蚤(Calanus sinicus)的食物组成、中型浮游动物和微型浮游动物对浮游植物群落的摄食压力进行了估算。研究结果表明春季调查区:中华哲水蚤对浮游植物的物种比摄食率介于0.01~8.43d-1,平均值为(2.72±2.14)d-1。中华哲水蚤对浮游植物的物种摄食速率介于0.05~838.23cells ind.-1d-1,平均值为(52.72±154.21)cells ind.-1d-1,对几种有害藻华原因生物的摄食速率较高。中华哲水蚤对浮游植物物种摄食速率具有食物密度依赖性,在低浮游植物丰度下,其摄食速率会随着浮游植物丰度的增加而增加,达到一定阈值后随着浮游植物丰度增加而逐渐降低。中型浮游动物群落对浮游植物群落碳摄食速率介于0.53~4.97ngC L-1d-1,平均值为(2.16±1.63)ngC L-1d-1。微型浮游动物对浮游植物群落物种平均碳摄食速率介于0.04~13.20ngC ind.-1d-1,平均值为(2.91±5.22)ngCind.-1d-1。微型浮游动物群落对浮游植物群落碳摄食速率介于61.07~8632.85ngC L-1d-1,平均值为(2801.01±4198.46)ngC L-1d-1。分析比较中型浮游动物和微型浮游动物对浮游植物现存量摄食压力表明,海区中微型浮游动物的摄食压力要远高于中型浮游动物,介于95.59%~99.98%,平均值为97.88%±2.33%。调查海区中型浮游动物还通过对微型浮游动物的摄食影响浮游植物生长。     

有害赤潮藻种塔玛亚历山大藻的研究进展

塔玛亚历山大藻(Alexandrium tamarense)是一种全球分布的有毒涡鞭毛藻,在中国的渤海、东海和南海海域均有分布。塔玛亚历山大藻是一种主要的有毒赤潮原因种,而且它能产生可经食物链传递后在贝类、鱼类等生物体内大量蓄积的麻痹性贝毒素,对水域环境和人类健康都具有极大的危害。因此,针对塔玛亚历山大藻的产生、发展以及毒素的特征等开展了广泛而深入的研究。本文主要从塔玛亚历山大藻的生长环境、分子鉴定、藻际竞争关系以及治理等方面进行了综述,为研究塔玛亚历山大藻的利弊和监控提供参考。     

春季东海中华哲水蚤对有害藻华物种的选择性摄食

2005年4月27日—6月5日在东海有害藻华高发区的6个典型站位采样,分析了浮游植物的群落结构,并采用现场实验研究了中华哲水蚤(Calanus sinicus)的选择性摄食.结果表明,中华哲水蚤对浮游植物的选择性摄食具有食物密度依赖性.低浮游植物细胞丰度下中华哲水蚤具有明显的选择性摄食行为,高浮游植物细胞丰度下中华哲水蚤摄食选择性由偏好转变为排斥,浮游植物细胞丰度329 cells·ml^-1是中华哲水蚤由偏好趋于排斥摄食的阈值.中华哲水蚤的选择性摄食还与食物组成有关,对于食物中的微型浮游动物,中华哲水蚤无选择性或排斥摄食.有害藻华发生区中华哲水蚤对具齿原甲藻(Prorocentrum dentatum)的偏好摄食以及对米氏凯伦藻(Karenia mikimotoi)的排斥摄食,促使藻华的物种演替最终向米氏凯伦藻水华方向发展.