Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907.
Appl Environ Microbiol. 1985 Mar;49(3):501-4. doi: 10.1128/aem.49.3.501-504.1985.
The percentage of [methyl-H]thymidine incorporated into samples from a dimictic eutrophic lake and retained on polycarbonate membranes of 3.0-, 1.0-, and 0.2-mum pore size was studied in a lake with filamentous cyanobacteria as the dominant phytoplankton type throughout the period of thermal stratification. Water samples were also examined by epifluorescence microscopy for evidence of algal senescence and bacterial colonization of intact and damaged cyanobacterial filaments. A small percentage (2 to 20%) of bacterial activity was retained by filters with pore sizes >/= 1 mum in epilimnetic samples. Epilimnetic samples also had a small percentage of cyanobacterial filaments, either intact or damaged, which were visibly colonized by bacteria in summer and fall samples. A significant proportion (20 to 35%) of bacterial activity was retained by filters with pore sizes >/= 1 mum in samples collected from the metalimnion and hypolimnion during late summer and fall. The proportion of damaged cyanobacterial filaments was higher in these samples than in those from the epilimnion or from those obtained early in the summer. Furthermore, the filaments in these samples were more heavily colonized by bacteria. Overall, particle-bound production accounted for only 2 to 19% of total bacterial production from April to August in all water layers. It appears that the supply of colonizable particles (damaged cyanobacterial filaments) is an important factor affecting the level of particle-bound bacterial activity in this lake.
研究了在富营养化的二相湖（分层期以丝状蓝藻为优势浮游植物）中，[甲基-³H]胸腺嘧啶掺入到 3.0μm、1.0μm 和 0.2μm 孔径的聚碳酸酯膜上的样品的百分比，以及用荧光显微镜检查水样品中是否有藻类衰老和完整及受损蓝藻丝上细菌定殖的证据。在表水层中，孔径大于等于 1μm 的滤膜截留了少量（2%到 20%）的细菌活性。在夏季和秋季的水样中，表水层的部分蓝藻丝，无论是完整的还是受损的，都有一小部分（20%到 35%）被孔径大于等于 1μm 的滤膜截留，且可见细菌定殖。在夏末和秋季从湖中间层和湖底层采集的水样中，孔径大于等于 1μm 的滤膜截留了大量（20%到 35%）的细菌活性。与表水层相比，这些样品中受损蓝藻丝的比例更高，而且这些样品中的丝状蓝藻丝也被细菌严重定殖。总的来说，从 4 月到 8 月，颗粒结合的细菌生产力仅占总细菌生产力的 2%到 19%。这表明可定殖颗粒（受损的蓝藻丝）的供应是影响该湖中颗粒结合细菌活性水平的一个重要因素。
