Distribution of living and dead diatoms in tidal wetlands of northern Japan: relations to taphonomy
Distribution of living and dead diatoms in tidal wetlands of northern Japan: relations to taphonomy
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DOI：
10.1016/s0031-0182(01)00313-3
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发表时间：
2001-09-15
影响因子：
3
通讯作者：
Sawai, Y
中科院分区：
文献类型：
--
作者：
Sawai, Y
本文介绍了对日本北部北海道东部四个潮汐沼泽中当代硅藻分布的调查结果，根据聚类分析定义，活硅藻细胞的分布与植被和基质有关，并且与潮位有明显关系。每个簇中活硅藻和死亡硅藻的比较提供了与潮汐湿地环境中硅藻埋藏学相关的协同学信息。识别出四种组合，总结如下。 (1) 由适应相对干燥条件的本土淡水硅藻组成的高地组合。 （2）在平均高潮位（MHTL）或略高于平均高潮位（MHTL）处形成的高沼泽组合，只有很少的外来成分。 (3) MHTL 下方形成低洼沼泽组合。该组合内的死阀通过潮汐过程重复广泛地重新分布。因此，该组合是一个“混合组合”，包括外来硅藻和本地硅藻的组合。 (4) 滩涂组合。滩涂中死亡的硅藻瓣膜立即被潮流重新分布，这里死亡的硅藻组合具有“原生”或“残余”组合的特征。基于分布模式的自体论视角可以推进这些解释。附生硅藻 Cocconeis scutellum 的死瓣具有一个针叶瓣（R-瓣）和一个无缝瓣（P-瓣），在两条样带上很常见，但只有 P-瓣广泛分布在代表该物种实际栖息地的海藻区之外。这种选择过程主要与单针鱼物种的生命形式特征有关：仅R阀在死亡时仍附着在其基质上，第浮游生物Paralia sp。也是分布广泛的物种。就帕拉利亚而言，它们的长链比其他样本更容易漂浮，很容易被潮汐流运输，然后被困在整个潮汐环境中。这些观察结果表明，潮汐沼泽沉积物中仅 C. scutellum 或 Paralia 的 P 瓣膜的浓度很可能应被视为硅藻组合中的异地成分。 (C) 2001 Elsevier Science B.V. 保留所有权利。
This paper presents the results of a survey of the contemporary diatom distributions in four tidal marshes of eastern Hokkaido, northern Japan, Distribution of living diatom cells, as defined by cluster analysis, have relations to vegetation and substratum, and clearly to tide level. Comparison between living and dead diatoms in each cluster provides synecological information relating to diatom taphonomy in the tidal wetland environments. Four assemblages are recognized and they are summarized as follows. (1) An upland assemblage consisting of autochthonous freshwater diatoms adapted to relatively dry conditions. (2) A high marsh assemblage formed at or slightly above mean high tide level (MHTL) with only few allochthonous components. (3) A low marsh assemblage formed below MHTL. Dead valves within this assemblage are repeated widely redistributed by tidal processes, This assemblage is therefore a 'mixed assemblage' comprising a combination of allochthonous and autochthonous diatoms. (4) A tidal flat assemblage. On death diatom valves in tidal flat are immediately redistributed by tidal currents, and the dead diatom assemblage here has the characteristics of an 'autochthonous' or 'residual' assemblage. Autectological perspectives based on the distribution patterns can advance these interpretations. Dead valves of the epiphytic diatom Cocconeis scutellum, which possesses a raphid valve (R-valve) and a rapheless valve (P-valve), are common on two transects but only P-valves are widely distributed beyond the seaweed zone which represents the actual habitat of this species. Such selective processes are related mainly to the life form characteristics of monoraphid species: only R-valves remain attached to their substratum on death, The tychoplankton Paralia sp. is also a widely distributed species. In the case of Paralia, their long chains float more readily than other specimens are transported easily by tidal currents, and then trapped in entire tidal environments. These observations suggest it is likely that concentrations of only P-valves of C. scutellum or Paralia in the tidal marsh deposits should be treated as allochthonous components in the diatom assemblage. (C) 2001 Elsevier Science B.V. All rights reserved.