Flow microenvironment of two marine peritrich ciliates with ectobiotic chemoautotrophic bacteria
Flow microenvironment of two marine peritrich ciliates with ectobiotic chemoautotrophic bacteria
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两种具有外生化能自养细菌的海洋周毛纤毛虫的流动微环境
DOI：
10.3354/ame029019
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发表时间：
2002
影响因子：
1.4
通讯作者：
J. Ott
中科院分区：
文献类型：
--
作者：
K. Vopel;C. Reick;G. Arlt;Martina Pöhn;J. Ott
2种海洋富围纤毛虫Vorticella sp.的流动微环境和具有外生硫磺细菌的Zootham-nium niveum，通过逐帧视频序列分析和流体速度微型传感器进行了研究。这两个物种都位于释放硫化氢的红树林泥炭上方的趋化层中。沃氏杆菌(Vorticella sp.)将周围的海水移动到水平和垂直距离至少400微米，最大流速为18毫米S-1靠近其口周边缘。羽毛形状的菌落产生单向的海水流动，穿过菌落垂直于茎；羽毛的凸面朝向上游。流向菌落的流速呈指数增长，在距离100微米处达到11 mm S-1。茎的收缩迫使Vorticella sp.和Z.niveum分别以71 mm和520 mm S-1的高速朝向底物。在Vorticella sp.的收缩过程中，只有少量海水被拖向纤毛虫附着的表面，而Z.niveum的收缩导致菌落周围和底物上方的海水速度明显增加。物种的伸展速度比收缩慢700到1000倍，周围的海水粘在细胞上，因此被拖着走。这里给出的测量结果支持我们早期的数据，表明摄食电流对细菌-纤毛虫联合的重要性，即纤毛节拍驱动含H_2S和O_2的海水高速向动物体移动，从而支持外生硫化物氧化细菌的生长。快速移动、收缩(Vorticella sp.)而在茎收缩期间，动物园的丛生(Z.niveum)显然会产生足够的剪应力来磨损外生细菌，一旦悬浮，这些细菌就可以进入摄食电流。
The flow microenvironment of 2 marine peritrich ciliates, Vorticella sp. and Zootham- nium niveum, with ectobiotic sulfur bacteria was studied with frame-by-frame analyses of video sequences and a microsensor for fluid velocity. Both species populate the chemocline above H2S- releasing mangrove peat. Vorticella sp. moves the surrounding seawater up to a horizontal and ver- tical distance of at least 400 µm with a maximum flow velocity of 18 mm s -1 close to its peristomial edge. The feather-shaped colonies of Z. niveum generate a unidirectional flow of seawater passing the colony perpendicular to the stalk; the convex side of the feather faces upstream. The flow veloc- ity increased exponentially towards the colony, up to 11 mm s -1 at a distance of 100 µm. Contraction of the stalk forces the zooids of Vorticella sp. and Z. niveum towards the substrate at a high velocity of 71 and 520 mm s -1 , respectively. During contraction of Vorticella sp., only little seawater is dragged along towards the surface to which the ciliates are attached whereas the contraction of Z. niveum resulted in a clear increase in the velocity of the seawater both surrounding the colony and above the substrate. Extension of the species proceeds 700 to 1000 times more slowly than contraction, and the surrounding seawater sticks to the cells and therefore is dragged along. The measurements given here support our earlier data indicating the importance of the feeding current for the bacteria-ciliate association, i.e. the cilia beat drives H2S- and O2-containing seawater toward the zooid at high veloc- ity and thus, supports the growth of the ectobiotic sulfide-oxidizing bacteria. Rapid movement, shrinkage (Vorticella sp.) and bunching (Z. niveum) of the zooids during stalk contraction apparently cause sufficient shear stress to abrade ectobiotic bacteria that, once suspended, could enter the feeding currents.