Dynamics of microbial communities on marine snow aggregates: Colonization, growth, detachment, and grazing mortality of attached bacteria
Dynamics of microbial communities on marine snow aggregates: Colonization, growth, detachment, and grazing mortality of attached bacteria
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DOI：
10.1128/aem.69.6.3036-3047.2003
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发表时间：
2003-06-01
影响因子：
4.4
通讯作者：
Ploug, H
中科院分区：
文献类型：
--
作者：
Kiorboe, T;Tang, K;Ploug, H
我们研究了附着在模型聚集体（直径4 mm的琼脂球）上的微生物群落的动态以及定植、分离、生长和放牧死亡的组成过程。在原始海水中培养的琼脂球很快被细菌定植，其次是鞭毛虫和纤毛虫。定植可以被描述为一个扩散过程，估计细菌和鞭毛虫的接触体积率分别为0.01和0.1 cm(3) h（-1）。在初始定殖后，鞭毛虫和纤毛虫的丰度大致保持在10(3)~ 10(4)和10(2)个细胞球（-1）之间，而细菌的数量则以下降的速度增加到10(7)个细胞球（-1）。附着的微生物最初以类似于10(-2)min（-1）的高特异性速率分离，但细菌逐渐不可逆地附着在球体上。细菌生长（0至2天（-1））依赖于密度，当细胞密度超过阈值时呈双曲线下降。嗜菌鞭毛虫以15个细菌（-1）h（-1）的平均饱和速率在球体表面上放牧。在低细菌密度下，鞭毛表面清除率为5 × 10(-7) cm(2) min(-1)，但随着细菌密度的增加而呈双曲线下降。利用实验估计的过程速率并将组成过程整合到一个简单的模型中，再现了观察到的微生物种群动态的主要特征。然而，观察到的种群动态和预测的种群动态之间的差异表明，其他因素，例如细菌之间的拮抗相互作用，在形成海洋雪微生物群落方面也很重要。
We studied the dynamics of microbial communities attached to model aggregates (4-mm-diameter agar spheres) and the component processes of colonization, detachment, growth, and grazing mortality. Agar spheres incubated in raw seawater were rapidly colonized by bacteria, followed by flagellates and ciliates. Colonization can be described as a diffusion process, and encounter volume rates were estimated at about 0.01 and 0.1 cm(3) h(-1) for bacteria and flagellates, respectively. After initial colonization, the abundances of flagellates and ciliates remained approximately constant at 10(3) to 10(4) and similar to10(2) cells sphere(-1), respectively, whereas bacterial populations increased at a declining rate to >10(7) cells sphere(-1). Attached microorganisms initially detached at high specific rates of similar to10(-2) min(-1), but the bacteria gradually became irreversibly attached to the spheres. Bacterial growth (0 to 2 day(-1)) was density dependent and declined hyperbolically when cell density exceeded a threshold. Bacterivorous flagellates grazed on the sphere surface at an average saturated rate of 15 bacteria flagellate(-1) h(-1). At low bacterial densities, the flagellate surface clearance rate was similar to5 x 10(-7) cm(2) min(-1), but it declined hyperbolically with increasing bacterial density. Using the experimentally estimated process rates and integrating the component processes in a simple model reproduces the main features of the observed microbial population dynamics. Differences between observed and predicted population dynamics suggest, however, that other factors, e.g., antagonistic interactions between bacteria, are of importance in shaping marine snow microbial communities.