Changes in cohesive sediment properties associated with the growth of a diatom biofilm
Changes in cohesive sediment properties associated with the growth of a diatom biofilm
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DOI：
10.1007/s10750-007-9099-9
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发表时间：
2007
期刊：
影响因子：
2.6
通讯作者：
T. Tolhurst;M. Consalvey;David M. Paterson
中科院分区：
文献类型：
--
作者：
T. Tolhurst;M. Consalvey;David M. Paterson
微藻生物膜与自然沉积物性质的相当大的变化有关，但很少有人努力分离出由生物膜生长引起的沉积物性质的微尺度时空变化。了解与生物膜生长相关的变化和量化这些变化发生的时间尺度对于开发合适的实验设计以及了解生物膜如何调节沉积物特性和过程非常重要。在45天的实验室里，研究了微底栖植物生物膜的发育和沉积物中相关的变化。沉积物的生物地球化学性质：体积密度、含水量、叶绿素浓度和胶体碳水化合物浓度在亚毫米尺度上进行了测量。用内聚强度仪（Cohesive Strength Meter， CSM）测定侵蚀阈值。生物膜发育迅速，1天后发生性质变化，3天后形成可见膜。随着时间的推移，沉积物性质的最大变化发生在200 μm的表层，一些变量也随深度的变化而变化。土壤表层2 mm的含水量、叶绿素浓度、胶体碳水化合物浓度和侵蚀阈值变化显著，随时间的推移总体呈增加趋势。堆积密度是高度可变的，并没有显示出一个一致的模式随着时间的变化。侵蚀阈值与200 μm表层含水量、叶绿素和胶体碳水化合物呈显著正相关，且三者之间呈显著正相关。低温扫描电镜（LTSEM）图像显示了表层沉积物结构的变化和厚多层生物膜的形成。在设计研究生物膜和沉积物特性的实验和/或涉及杀菌剂处理或对沉积物的干扰时，应考虑生物膜生长和发育的速度以及与沉积物相关的变化。
Microalgal biofilms are associated with considerable variability in the properties of natural sediments, yet little effort has been made to isolate micro-scale spatial and temporal changes in sediment properties caused by the growth of a biofilm. Understanding the changes associated with biofilm growth and quantifying the time scales over which these changes occur is important for developing suitable experimental designs and for understanding how biofilms mediate sediment properties and processes. The development of a microphytobenthic biofilm and associated changes in the sediment was investigated over 45 days in the laboratory. The biogeochemical properties of the sediment: bulk density, water content, chlorophyllaconcentration and colloidal carbohydrate concentration were measured on a sub-millimetre scale in the top 2 mm. The erosion threshold was measured with a Cohesive Strength Meter (CSM). Biofilm development was rapid, with changes in the properties occurring after 1 day and a visible film forming after just 3 days. The largest changes in sediment properties tended to occur in the surface 200 μm through time, with some variables also showing a differing response with depth. There were significant changes in water content, chlorophyllaconcentration, colloidal carbohydrate concentration and erosion threshold in the surface 2 mm, with a general trend to increase with time. Bulk density was highly variable and did not show a consistent pattern of change with time. Erosion threshold was positively correlated with water content, chlorophyllaand colloidal carbohydrate in the surface 200 μm and these were also positively correlated with each other. Low Temperature Scanning Electron Microscopy (LTSEM) images revealed changes in the surface sediment structure and the formation of a thick multi-layer biofilm. The rapidity of biofilm growth and development and the associated changes to the sediment should be considered when designing experiments that investigate biofilms and properties of sediments and/or that involve biocide treatments or disturbance to the sediment.