湿地沉积硅藻记录及其古环境应用研究进展

Diatoms Species in Wetlands Sediments and Its Paleoenvironmental Implication: A Review

湿地是由陆地和水体系统相互作用形成的自然复合生态系统,在维护区域生态平衡中发挥着重要作用。由于全球气候变化和高强度人类活动等的影响,湿地出现了一系列生态问题。为了将湿地恢复到较为健康的状态,需要根据湿地未受到人类活动影响或人类活动影响较小时期的生态特征,制定湿地恢复目标,因此,首先要追溯历史时期湿地的环境变化。硅藻是一类广泛地分布在世界大洋和淡水水体中的浮游生物,由于湿地特殊的积水环境,硅藻同样广泛地分布在湿地生态系统中。硅藻生命周期较短、对环境变化敏感,容易鉴定和量化,适合作为其生境变化的指示生物。研究湿地中的硅藻,对探讨湿地生态系统中环境因子的变化和重建区域古环境具有重要意义。通过对湿地生态系统中硅藻的国内外研究成果的整理,参照其它生态系统中硅藻的研究工作,对湿地生态系统中硅藻的研究现状进行了综述;并展望了未来研究方向。

Wetlands are natural complex ecosystem which formed by the interaction of terrestrial and aquatic systems. Due to wetlands have many ecological functions（e.g. water storage, regional climate regulation, air purification）, they play an important role in maintaining regional ecological security and ecological balance.With the increasing impact of global climate change and high-intensity human activities, the environment of the wetlands received serious destruction and faced with the decreasing of water levels, pollution of water quality, destruction of habitats, reducing of biodiversity and so on. In order to restore degraded wetland, ecological conditions（e.g. vegetation, water level, the quality of water） in the period when wetlands are not affected by human activities should be selected as reference conditions for wetland restoration. Therefore, it is particularly important to reconstruct the wetland environmental characteristics that are not affected by human activities. Diatoms, taxa of plankton, are widely distributed in ocean and freshwater systems. Diatoms are primary producers in the aquatic ecosystem and act as essential parts of the food chain. Due to the siliceous cell walls of diatoms, the dead diatom shell is not decomposed and deposits in the sediment for a long time. Diatoms are widely used to monitor modern environments and reconstruct paleoenvironmental conditions because of the special characteristics of diatoms. Such as diatoms are widely distributed in humid environments,different diatom species indicate different environmental information, the frustule of diatoms are well stored in sediments, and valves of different genus diatoms are easy to identify. The application of diatom as a biological indicator has been extensively studied in aquatic ecosystem in China, but most of researchers now focus on lake ecosystems. Since wetlands are formed by the interaction of terrestrial ecosystems and aquatic ecosystems, diatoms can also be used as one of the indicators for monitoring changes of wetland environmental factors and reconstructing the paleoenvironment of wetlands. Although some studies have focused on wetland diatom research, systematic research is still inefficient. The potential environmental significance of diatoms in wetlands is not fully understood. In this paper, diatom researches in the wetlands around the world are summarized and compare with related works of diatoms in other aquatic ecosystems. The current results of diatom research in wetland are reviewed and several suggestions on how to improve diatom research in wetlands in the future are also proposed. It is hoped that our research results will be helpful to the study of diatoms in wetlands in the future.