雨养泥炭沼泽古水文定量重建的代用指标——有壳肉足虫化石记录的应用与进展

A POWERFUL INDICATOR FOR QUANTITATIVE RECONSTRUCTION OF OMBROTROPHIC MIRES PALAEOHYDROLOGY: ADVANCES IN THE STUDY OF FOSSIL TESTATE AMOEBAE

  • 摘要: 有壳肉足虫是由壳体包裹细胞质的单细胞原生动物,由于它种类多、对雨养泥炭沼泽水文变化反应敏感且其壳体易于保存,成为一种雨养泥炭沼泽古水文定量重建的代用指标。主要阐述了现代雨养泥炭沼泽有壳肉足虫-环境变量数据库建立的方法和具体步骤,及该指标在古水文及古气候重建上的应用和研究进展。在以欧美为主的地区进行的许多研究发现,利用有壳肉足虫恢复的地下水位记录不仅与其他BSW指标(如植物大化石和腐殖化度)记录变化有很好的一致性,而且它与其他陆地古气候指标、冰心指标、海洋指标及太阳辐射指标等都存在良好的对应关系,充分证实了有壳肉足虫是一种雨养泥炭沼泽古水文的有效代用指标,其重建的地下水位记录能够很好地反映区域古气候的变化。然而截至目前,有壳肉足虫分类学研究、现代生态模拟等方面所存在的问题仍是其应用研究的阻碍,相信随着这些问题的逐步解决,有壳肉足虫在雨养泥炭沼泽古水文及古气候重建上将发挥更大的作用。我国在该领域尚未开展研究,存在较好的研究潜力,而且其成果可以对我国泥炭地的生态管理、开发利用提供科学指导依据。

     

    Abstract: According to chemical conditions, peatlands usually have three types., minerotrophic, ombrotrophic and transition. Nutrients of ombrotrophic mires mainly come from precipitation. Because surface water in the mires moves quite slowly, most of deposits remain their formative sets. There are a number of testate amoebae on ombrotrophic mires, which are single-celled organisms in which the cytoplasm is enclosed within an external shell. Studies of their ecology show that assemblages are principally determined by moisture status but are also influenced by nutrient status, especially by pH levels. Testate amoebae provide an additional technique and have ability to quantitatively reconstruct water table depths.
    The paper introduces the method and steps of building up a large quality modern dataset of surface sediment samples and associated environmental variables on ombrotrophic mires, which is precondition of reconstruction of palaeohydrology, and then reviews existing and recently developed application of testate amoebae analysis to reconstruct palaeohydrology of ombrotrophic mires. In Europe and North America, many researches have found that the records of water table levels on ombrotrophic mires based on testate amoebae analysis well agree with bog surface wetness (BSW) from plant macrofossils and humification analysis, and are also correlated with the ice rafted debris (IRD) record in the North Atlantic Ocean and cosmogenic isotope flux. The results indicate that testate amoebae are sensitive indicators for paleohydrology, and water table reconstructions from testate amoebae can provide a new source of palaeoclimate data for temperate oceanic regions with ombrotrophic mires.
    In China, little progress has been made now in the utilization of testate amoebae for reconstruction of palaeohydrology. Obviously, there are potentials to use testate amoebae in the peatlands of China as an indicator for environment, and the researches are useful scientific guidance for the ecological management and the exploitation of the peatlands in China.

     

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