THE IMPACT OF STORM‐FLOW ON RIVER BIOFILM ARCHITECTURE 1
THE IMPACT OF STORM‐FLOW ON RIVER BIOFILM ARCHITECTURE 1
复制标题
暴风雨对河流生物膜结构的影响 1
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
M. Lock
中科院分区：
文献类型：
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作者：
S. Blenkinsopp;M. Lock
采用透射电镜（TEM）和扫描电镜（SEM）研究了暴雨流对河流生物膜结构的影响。TEM树脂基质在光生长（LG）或暗生长（DG）条件下在北威尔士的Clywedog河中定殖33周，然后暴露于环境流（约100 ℃）。60 cm·s − 1）或暴雨流（约235 cm·s − 1+河流沉积物）。线横断面方法用于量化LG材料的TEM切片的信息。在LG环境流生物膜中，直接邻近基质的细菌更丰富，并且直接在贴生硅藻Cocconeis下明显更密集。在生物膜的更高处，细菌松散地分散在其他细胞之间的基质中。蓝细菌最常以单细胞形式出现，但也可在邻近底层的大型"栅栏"结构中发现。细菌和蓝藻都有显著的水平和垂直最近邻关联。卵形藻的细胞常见于底层附近，为细菌、蓝藻和密集染色的胞外多糖的"有机垫"提供庇护，并经常升高。蓝细菌和卵形藻对风暴流的去除有抵抗力，但卵形藻的硅藻壳有时会被破坏。LG暴雨流样本中的细菌在邻近底层的地方不太常见，有时在生物膜中的分散程度高于环境流样本。我们认为风暴流水动力可能会将底层附近的细菌重新分配到生物膜的较高区域。此外，细菌和胞外多糖基质有时会被风暴流带到底层，除非在Cocconeis下面。DG生物膜几乎完全由细菌组成。风暴流仅去除了DG生物膜的表面生长，SEM显示了周向茎磨损和"吹落"。干扰前生物膜结构似乎影响破坏的形式。我们认为，"缩影"的Cocconeis和他们的底层细胞不仅作为接种体，以prononize表面时，条件允许，但提高移民中断流动模式的表面。
The impact of storm‐flow on river biofilm architecture was investigated using transmission (TEM) and scanning (SEM) electron microscopy. TEM resin substrata were colonized under light‐grown (LG) or dark‐grown (DG) conditions for 33 weeks in the Clywedog River, North Wales, prior to exposure to ambient‐flow (approx. 60 cm·s−1) or storm‐flow (approx. 235 cm·s−1+ river sediment) in a laboratory flume. Line transect methodology was used to quantify information from TEM ultrathin sections of LG material. In the LG ambient‐flow biofilm, bacteria were more abundant directly adjacent to the substratum and were noticeably denser directly under the adnate diatom Cocconeis. Higher in the biofilm, the bacteria were loosely dispersed in the matrix between other cells. Cyanobacteria occurred most frequently as single cells but were also found in large “palisade” formations adjacent to the substratum. Significant horizontal and vertical nearest‐neighbor associations were noted for both bacteria and cyanobacteria. Cells of Cocconeis were common adjacent to the substratum, providing shelter to, and often elevated upon, an “organic pad” of bacteria, cyanobacteria, and densely staining exopolysaccharide. Cyanobacteria and Cocconeis were resistant to removal by storm‐flow, but Cocconeis frustules were sometimes damaged. Bacteria in the LG storm‐flow samples were less common adjacent to the substratum and were sometimes more dispersed higher in the biofilm than in ambient‐flow samples. We suggest that storm‐flow hydrodynamic forces may redistribute bacteria adjacent to the substratum into higher areas of the biofilm. In addition, bacteria and the exopolysaccharide matrix were sometimes removed down to the substratum by storm‐flow, unless beneath Cocconeis. The DG biofilm consisted almost entirely of bacteria. Storm‐flow only removed surface growth from DG biofilms, and SEM revealed peritrich stalk abrasion and “blow‐down.” Pre‐disturbance biofilm architecture appears to influence the form of destruction. We suggest that the “microcosms” of Cocconeis and their underlying cells not only serve as an inoculum to recolonize the surface when conditions permit but enhance immigration by interrupting flow patterns across the surface.