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首页> 外文期刊>Marine ecology progress series >Diatom activity within soft sediments: behavioural and physiological processes
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Diatom activity within soft sediments: behavioural and physiological processes

机译：软质沉积物中的硅藻活性：行为和生理过程

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摘要

An investigation of vertical distribution, rhythms of vertical migration and division of epipelic free-living diatom algae was carried out at different sediment depths on intertidal sandflat in the Chernaya River Estuary (Kandalaksha Gulf, White Sea, Russia) during the summers of 1994-2001. The depth of penetration of viable microalgae cells in the sediment did not exceed 4.2 cm in the areas with clay sublayers, where zones with high negative Eh values were located closer to the surface. Diatom habitats in the areas with coarse sand sublayers extended to more than 8 cm depth. Approximately 40% of diatoms were present in the topmost 2 mm layer. The subsurface portion of diatom cells on average was concentrated within the layer with Eh values ranging from 0 to -80 mV. Eh values below -100 mV limited diatom penetration in deep anoxic sediment layers. The deep portion of diatom populations consisted basically of dividing cells. A cytological analysis of diatom cell distribution showed that the proportion of cells in the different phases of mitosis increased with increasing depth, and reached 80 to 90% at a depth of 2 to 3 cm. The regular presence of dividing diatom cells almost exclusively in aphotic anoxic sediments was noted first. The study of the dynamics of microphytobenthic vertical distribution revealed active diurnal vertical migration depending on temperature, light and tide regimes. The frequency of doublet cells (FDC) in epipelic diatom populations was in inverse proportion to cell concentrations in the photic zone. Diatom division was registered only during incubation in the porewater, which was rich in inorganic nutrients and dissolved organic matter. We suppose that a more stable habitat with higher concentrations of nutrients (especially nitrogen) in their more reduced forms (NH_4~+ instead of NO_3~-) provides more favourable conditions for cell growth and division at the depth of several cm within the sediment compared, to the surface layer. Migration activity of diatom algae is an adaptation which permits cells to consume energy and to undergo fission under optimum conditions in spatially disconnected zones.
机译：在1994-2001年夏季，对Chernaya河口（Kandalaksha湾，俄罗斯白海）潮间带滩涂不同深度的沉积物进行了垂直分布，垂直迁移的节奏和上生自由活动的硅藻藻类的划分的研究。 。在具有粘土亚层的区域中，具有高Eh负值的区域更靠近地表，活的微藻细胞在沉积物中的渗透深度不超过4.2 cm。粗砂子层区域的硅藻生境延伸到8厘米以上。最上面的2 mm层中约有40％的硅藻存在。平均硅藻细胞的表面下部分集中在层内，Eh值范围为0至-80 mV。低于-100 mV的Eh值限制了深层缺氧沉积物中硅藻的渗透。硅藻种群的深层部分基本上由分裂细胞组成。硅藻细胞分布的细胞学分析表明，有丝分裂不同阶段的细胞比例随深度的增加而增加，在2至3 cm的深度达到80％至90％。首先注意到分裂的硅藻细胞几乎完全存在于无氧缺氧沉积物中。对微植物底栖动物垂直分布的动力学研究表明，活跃的昼间垂直迁移取决于温度，光照和潮汐制度。表皮硅藻种群中双峰细胞（FDC）的频率与光合区细胞浓度成反比。硅藻的分裂仅在孵化过程中才被记录，该孔隙水中富含无机养分和溶解的有机物。我们认为，较稳定的生境具有较高的养分浓度（尤其是氮），且其形式更简化（NH_4〜+代替NO_3〜-），为沉积物内几厘米深度的细胞生长和分裂提供了更有利的条件。 ，到表面层。硅藻藻类的迁移活动是一种适应性活动，它使细胞能够在空间隔离区域的最佳条件下消耗能量并进行裂变。

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