厦门沿岸自然浮游细菌种群对于病毒裂解产物的响应

Response of planktonic bacteria to viral lysates in coastal waters of Xiamen

模拟了厦门沿岸海区病毒裂解产物对于自然细菌群落的影响.实验过程中基于不同过滤方式收集的细菌、病毒种群和病毒裂解产物,通过室内模拟培养方式,结合流式细胞计数和总有机碳分析仪分析病毒、细菌丰度和有机碳含量等技术,研究浮游细菌在病毒裂解产物添加下的生长变化.实验结果显示,去除原生生物捕食者的浮游细菌丰度在整个培养过程中持续增加,特别是病毒裂解产物添加组中的细菌类群的增长程度明显,其丰度在5 d的培养时间内从2.76×10^5cells/cm^3上升至1.90×10^6cells/cm^3;而在无病毒裂解产物添加组中其丰度仅仅从3.0×10^5cells/cm^3上升至1.39×10^6cells/cm^3;相对于无病毒裂解产物添加组,培养周期内细菌丰度均值在病毒裂解产物添加组中的绝对增量约为3.64×10^5cells/cm^3,这表明此研究海区的病毒裂解产物在模拟原位环境的培养体系中可快速地被环境中的其他细菌类群吸收、利用,并且在丰度上产生显著影响（p〈0.05）.结合病毒丰度变化以及细菌细胞裂解释放量、细胞碳含量的关系估算了收集来的病毒裂解产物在培养体系中释放的碳量大约为2.12-7.67μg/（dm^3·d）;它被浮游细菌用于丰度增长方面的贡献大约22.47%-81.25%.此外,在培养过程中,溶解有机碳的浓度在病毒裂解产物添加组中的变化相对于无病毒裂解产物添加组缓慢,但总体上两者随时间变化逐渐减少,它们间的均值差值约为1.04μmol/dm^3;结合对应的细菌丰度增量,估算出培养体系中浮游细菌碳含量大约为34.29fg/cell.上述结果揭示了厦门沿岸海域内病毒裂解产物在维持细菌群落多样性和生长繁殖方面的重要生态作用.

This study was to simulate the impact of viral lysates on natural planktonic bacteria in coastal seawaters of Xiamen. For incubations,planktonic bacteria,including viruses and viral lysates,were collected after filtrations and incubated with or without viral lysates as treatments. Following the incubation,the growth of bacteria were tracked and addressed by means of flow cytometry and total organic carbon analyzer. The results showed that abundances of planktonic bacteria in the whole incubations increased with removal of protist predator,especially in the add-on treatment of viral lysates. After 5 days incubations,density was higher in approximately 3. 64 × 10^5 cells / cm^3 in viral lysates add-on treatment,which increased from 2. 76 × 10^5 cells / cm^3 to 1. 90 × 10^6 cells / cm^3,than that of no viral lysates addition,which increased from 3. 0 × 10^5 cells / cm^3 to 1. 39 × 106 cells / cm^3. It indicated that the added viral lysates in incubation were quickly utilized by the growing bacteria and resulted in a significant difference（ p 〈0. 05） in abundance. Based on the abundance changes of viruses and bacteria,the burst size and the carbon content of a cell the amount of carbon released was calculated and estimated to be 2. 12 - 7. 67μg /（ dm^3·d） for the viral lysates collected in the add-on treatment and it contributed for 22. 47% - 81. 25% of the bacterium growth. In addition,development of dissolved organic carbon in the add-on treatment was slower than that in the non-additional treatment and the difference between them was about 1. 04 μmol / dm^3. It suggests that carbon content by bacterial increment is about 34. 29 fg / cell. The results reveal that in situ viral lysates in Xiamen coastal seawaters have ecologically played an important role in maintaining the diversity and growth of microbial communities.