摘要
通过对近十几年来河口最大浑浊带浮游植物生态动力过程研究的报道进行综述 ,阐明该方面研究的最新进展。研究结果表明 ,河口最大浑浊带的湍流混合过程增大了浮游植物细胞光合作用的机会 ;重力环流致使浮游植物及其光合作用所需的物质能较长时间的停留 ;再悬浮过程使微型底栖藻类对最大浑浊带水体中叶绿素产生明显贡献 ;锋面强烈的辐合聚集作用则可使浮游植物在锋面附近出现高值现象。最后对河口最大浑浊带浮游植物生态动力过程的继续研究提出了几点看法。
The physical processes effects on plankton, and the interactions between physical processes and biological processes are the main research field of GLOBEC. Estuary is an important area of human activities, complex dynamical processes and frail ecology. The importance of research on estuary has been gradually recognized since the research plan of LOICZ was put forward by IGBP. Estuarine ecosystem is similar to marine ecosystem in many aspects. However, because the biological condition and transport processes are different, the structure of biological population and spatial variation are also different, a special ecosystem is formed in the estuary. The special horizontal transport caused by the interaction between the dynamics of river and ocean, front, stratification, turbulence mixing are the important dynamical processes. The functions of these processes in estuarine ecosystem have not been understood well yet. The dynamical processes of phytoplankton ecology in maximum turbidity zone of estuary are the distinguishing features of estuarine ecosystem. In recent decades, progress in research on this field has been achieved. The maximum turbidity zone is one of the special dynamical phenomena in tidal estuary. It is the cloudy waters in which the concentration of suspended particular matter (SPM)is higher than that in the upper river and down sea area, and it often moves upper and down regularly in a certain range. Maximum turbidity zone can been found in every tidal estuary in every climate condition in the world, specially it develops very well in part mixing estuary and full mixing estuary. The initial stage research of maximum turbidity zone has been focused on deposition dynamics in estuary, then on the characteristic and regular pattern of geochemistry. In recent years, the research has been focused on its biogeochemistry, ecology and environment. The results indicated that the maximum turbidity zone has the function of enriching heavy metals and other pollutants. The pollutants can be absorbed by phytoplankton, and then affect the whole estuarine ecosystem by food chain. In other way, the maximum turbidity zone is the area for fish feeding and spawning, and fish population is also abundant in this area. Therefore, it is important to study phytoplankton ecology in maximum turbidity zone. A few research results indicated that the dynamical processes of turbulence mixing in maximum turbidity zone have obvious influence on phytoplankton ecology. Generally speaking, estuary is nutrient\|rich but turbid, so that algal productivity and population growth rate are limited primarily by light availability. Therefore, assume it to be true that turbid estuaries are unproductive ecosystems and that primary production is delayed relative to the clearer marine waters. However, very high rate of production have also been found in estuarine turbidity zone. For example, algal bloom occurred in the maximum turbidity zone of Great Ouse estuary, England. Due to relative thinness of the euphotic zone, mixing depth was assumed to be the main factor influencing phytoplankton production in turbid systems. Production processes in these environments depends on sequential exposure to the light due to the turbulent mixing that carries algal cells up and down the water column. In the case of the Great Ouse estuary the absence of stratification demonstrated that, the whole water column was well mixed, the mixing depth being therefore equal to the water depth. Consequently, phytoplankton development is possible if the critical depth is more than the water depth. The ‘entrapment effects' in the maximum turbidity zone of estuary is mainly caused by gravitational circulation. Concerning photosynthesis only occurring in light time and large amount of nutrient being necessary during algal bloom, the long retention time of nutrient caused by the ‘entrapment effects' is the important factor of algal bloom in the maximum turbidity zone. In another way, the ‘entrapment effects' can also bring phytoplankton staying in maximum turbidity zone for a l
出处
《生态学报》
CAS
CSCD
北大核心
2002年第9期1527-1533,共7页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目 (4 0 1 760 3 4)
中国科学院知识创新工程资助项目 (KZCX2 -2 0 6)
广东省重大科技兴海资助项目 (A2 0 0 0 99F0 1 )
广东省科技创新百项工程资助项目 (2 KB0 670 1 S)
关键词
河口最大浑浊带
浮游植物
生态动力过程
estuarine maximum turbidity zone
phytoplankton ecology
dynamical processes
