Department of Zoology, Michigan State University, 48824, East Lansing, Michigan.
Microb Ecol. 1988 Sep;16(2):165-81. doi: 10.1007/BF02018912.
Bacteria attached to rock and glass surfaces were studied in streams draining a whole-tree harvested watershed (WTH) and a nonharvested (CONTROL) watershed in the Hubbard Brook Experimental Forest, New Hampshire, U.S.A. Seasonal trends in numbers of cells/cm(2), mean cell volume, cell size-frequency distribution, and bacterial biomass were determined using 4'6-diamidino-2-phenylindole (DAPI) epifluorescent microscopy and scanning electron microscopy (SEM); the response of these parameters to decreased pH and increased nitrate concentration in the WTH stream was assessed via controlled manipulation of stream water chemistry in artificial channels placed in the CONTROL stream. Bacterial distribution varied significantly between the two streams and seasonally within each stream in apparent response to differential availability of dissolved organic carbon from algae and autumn-shed leaves. Decreased pH similar to that in the WTH stream had a significant effect on cell numbers, mean cell volume, and biomass in the CONTROL stream. Decreased pH accounted for some aspects of the altered bacterial distributions observed in the WTH stream. Nitrate at concentrations similar to those in the WTH stream had no effect on bacterial distribution in the CONTROL stream suggesting that headwater stream epilithic bacteria were carbon limited.
在美国新罕布什尔州哈伯德布鲁克实验森林中，研究了从整片采伐流域（WTH）和未采伐流域（CONTROL）中溪流中附着在岩石和玻璃表面的细菌。使用 4'6-二脒基-2-苯基吲哚（DAPI）荧光显微镜和扫描电子显微镜（SEM），确定了细胞/cm(2)数量、平均细胞体积、细胞大小频率分布和细菌生物量的季节性趋势；通过在 CONTROL 溪流中放置人工通道来控制溪流水化学，评估了这些参数对 WTH 溪流中 pH 值降低和硝酸盐浓度增加的响应。细菌分布在两条溪流之间以及每条溪流的季节之间存在显著差异，这显然是对藻类和秋季落叶中溶解有机碳的差异可利用性的反应。类似于 WTH 溪流中的 pH 值降低对 CONTROL 溪流中的细胞数量、平均细胞体积和生物量有显著影响。pH 值降低解释了在 WTH 溪流中观察到的细菌分布变化的某些方面。类似于 WTH 溪流中的硝酸盐浓度对 CONTROL 溪流中细菌分布没有影响，表明上游溪流的表生细菌受到碳限制。
