Effects of current velocity on the nascent architecture of stream microbial biofilms
Effects of current velocity on the nascent architecture of stream microbial biofilms
复制标题
DOI：
10.1128/aem.69.9.5443-5452.2003
复制
发表时间：
2003-09-01
影响因子：
4.4
通讯作者：
Hansen, C
中科院分区：
文献类型：
--
作者：
Battin, TJ;Kaplan, LA;Hansen, C
水流速度影响了森林覆盖的山前溪流中自然、多门和跨营养级生物膜的结构和动态。我们通过共焦激光扫描显微镜与冷冻切片相结合，监测了在两种流态（慢速[0.065 m s(-1)]和快[0.23 m s(-1)]）下运行的河边水槽中生物膜的发育和活性，以观察生物膜的结构和成分。生物膜的生长始于嵌入细胞外聚合物中的细菌微菌落，并转变为波纹状结构，最终形成明显的准六边形网络。这些结构在低流速下生长的生物膜中尤其明显，其特征是羽状硅藻沿着其长轴定向形成六边形。微观结构异质性是动态的，在较慢速度下形成的生物膜比在较高速度下形成的生物膜更厚，具有更大的表面蜿蜒度和更高的面密度。表面蜿蜒度和生物膜破碎随着厚度的增加而增加，这些变化可能降低了溶质从水柱到生物膜的传质阻力。然而，对溶解有机碳吸收和微生物生长的估计表明，碳的内循环在慢流条件下生长的厚生物膜中更为重要。对胞外多糖的高压液相色谱脉冲电流检测分析表明，随着葡萄糖水平的降低以及鼠李糖、半乳糖、甘露糖、木糖和阿拉伯糖的水平的增加，单糖组成发生时间变化。我们将化学成分的这种变化归因于硅藻的积累和成熟生物膜中碎屑颗粒掺入的增加。
Current velocity affected the architecture and dynamics of natural, multiphyla, and cross-trophic level biofilms from a forested piedmont stream. We monitored the development and activity of biofilms in streamside flumes operated under two flow regimes (slow [0.065 m s(-1)] and fast [0.23 m s(-1)]) by combined confocal laser scanning microscopy with cryosectioning to observe biofilm structure and composition. Biofilm growth started as bacterial microcolonies embedded in extracellular polymeric substances and transformed into ripple-like structures and ultimately conspicuous quasihexagonal networks. These structures were particularly pronounced in biofilms grown under slow current velocities and were characterized by the prominence of pennate diatoms oriented along their long axes to form the hexagons. Microstructural heterogeneity was dynamic, and biofilms that developed under slower velocities were thicker and had larger surface sinuosity and higher areal densities than their counterparts exposed to higher velocities. Surface sinuosity and biofilm fragmentation increased with thickness, and these changes likely reduced resistance to the mass transfer of solutes from the water column into the biofilms. Nevertheless, estimates of dissolved organic carbon uptake and microbial growth suggested that internal cycling of carbon was more important in thick biofilms grown in slow flow conditions. High-pressure liquid chromatography-pulsed amperometric detection analyses of exopolysaccharides documented a temporal shift in monosaccharide composition as the glucose levels decreased and the levels of rhamnose, galactose, mannose, xylose, and arabinose increased. We attribute this change in chemical composition to the accumulation of diatoms and increased incorporation of detrital particles in mature biofilms.