Diatom-associated bacteria are required for aggregation of Thalassiosira weissflogii
Diatom-associated bacteria are required for aggregation of Thalassiosira weissflogii
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DOI：
10.1038/ismej.2010.145
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发表时间：
2011-03-01
期刊：
影响因子：
11
通讯作者：
Ullrich, Matthias S.
中科院分区：
文献类型：
--
作者：
Gaerdes, Astrid;Iversen, Morten H.;Ullrich, Matthias S.
藻类（主要是硅藻）的聚集是海洋系统中的一个重要过程，导致主要以海洋雪的形式沉降的颗粒有机碳。浮游植物的渗出产物形成透明的外聚合物颗粒（TEP），其充当颗粒聚集的胶。异养细菌与浮游植物的相互作用可能会影响TEP的形成和浮游植物的聚集。这种细菌影响尚未详细探讨。我们假设，细菌附着到海链藻weissfloclavis可能会相互作用，在一个尚未确定的方式，这可能会影响TEP的形成和聚集丰度。个体T.在体外研究了用于TEP生产和硅藻聚集的Weissflogii附着和自由生活的新细菌分离物。T. weissflococcus没有聚集在无菌培养，聚集动力学和TEP丰度显着差异时，观察硅藻培养物接种无论是附着或自由生活的细菌。这些数据表明，自由生活的细菌可能不会影响聚集，而附着在硅藻细胞上的细菌可能会增加聚集体的形成。有趣的是，光合失活T.无论是否存在细菌，魏氏细胞都不聚集。通过对骨料形成、TEP生成、骨料沉降速度和固体水化密度的比较，发现二者之间存在显著差异。光合活性T.聚集需要Weissflocculant和特异性粘附细菌。结果表明，异养菌和硅藻之间的相互作用增加了聚集体的形成和颗粒下沉，从而可能提高生物泵的效率。The ISME Journal（2011）5，436-445; doi：10.1038/ismej.2010.145; 2010年9月9日在线发表
Aggregation of algae, mainly diatoms, is an important process in marine systems leading to the settling of particulate organic carbon predominantly in the form of marine snow. Exudation products of phytoplankton form transparent exopolymer particles (TEP), which acts as the glue for particle aggregation. Heterotrophic bacteria interacting with phytoplankton may influence TEP formation and phytoplankton aggregation. This bacterial impact has not been explored in detail. We hypothesized that bacteria attaching to Thalassiosira weissflogii might interact in a yet-to-be determined manner, which could impact TEP formation and aggregate abundance. The role of individual T. weissflogii-attaching and free-living new bacterial isolates for TEP production and diatom aggregation was investigated in vitro. T. weissflogii did not aggregate in axenic culture, and striking differences in aggregation dynamics and TEP abundance were observed when diatom cultures were inoculated with either diatom-attaching or free-living bacteria. The data indicated that free-living bacteria might not influence aggregation whereas bacteria attaching to diatom cells may increase aggregate formation. Interestingly, photosynthetically inactivated T. weissflogii cells did not aggregate regardless of the presence of bacteria. Comparison of aggregate formation, TEP production, aggregate sinking velocity and solid hydrated density revealed remarkable differences. Both, photosynthetically active T. weissflogii and specific diatom-attaching bacteria were required for aggregation. It was concluded that interactions between heterotrophic bacteria and diatoms increased aggregate formation and particle sinking and thus may enhance the efficiency of the biological pump. The ISME Journal (2011) 5, 436-445; doi: 10.1038/ismej.2010.145; published online 9 September 2010