Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Environ Sci (China). 2016 Apr;42:19-31. doi: 10.1016/j.jes.2015.08.005. Epub 2015 Sep 13.
Biofilms have important effects on nutrient cycling in aquatic ecosystems. However, publications about the community structure and functions under laboratory conditions are rare. This study focused on the developmental and physiological properties of cultured biofilms under various phosphorus concentrations performed in a closely controlled continuous flow incubator. The results showed that the biomass (Chl a) and photosynthesis of algae were inhibited under P-limitation conditions, while the phosphatase activity and P assimilation rate were promoted. The algal community structure of biofilms was more likely related to the colonization stage than with the phosphorus availability. Cyanobacteria were more competitive than other algae in biofilms, particularly when cultured under low P levels. A dominance shift occurred from non-filamentous algae in the early stage to filamentous algae in the mid and late stages under P concentrations of 0.01, 0.1 and 0.6 mg/L. However, the total N content, dry weight biomass and bacterial community structure of biofilms were unaffected by phosphorus availability. This may be attributed to the low respiration rate, high accumulation of extracellular polymeric substances and high alkaline phosphatase activity in biofilms when phosphorus availability was low. The bacterial community structure differed over time, while there was little difference between the four treatments, which indicated that it was mainly affected by the colonization stage of the biofilms rather than the phosphorus availability. Altogether, these results suggested that the development of biofilms was influenced by the phosphorus availability and/or the colonization stage and hence determined the role that biofilms play in the overlying water.
生物膜对水生生态系统的养分循环有重要影响。然而，关于实验室条件下生物膜群落结构和功能的出版物却很少。本研究重点关注在严格控制的连续流动培养箱中，不同磷浓度下培养的生物膜的发育和生理特性。结果表明，在磷限制条件下，藻类的生物量（Chl a）和光合作用受到抑制，而磷酸酶活性和磷同化率则得到促进。生物膜中藻类的群落结构更可能与定殖阶段有关，而与磷的可利用性关系不大。在低磷水平下，蓝藻比其他藻类更具竞争力，尤其是在生物膜中培养时。在磷浓度为 0.01、0.1 和 0.6 mg/L 时，从早期的非丝状藻类到中期和后期的丝状藻类发生了优势种转变。然而，生物膜的总氮含量、干重生物量和细菌群落结构不受磷可利用性的影响。这可能是由于在低磷条件下，生物膜的呼吸速率低、胞外聚合物的积累高和碱性磷酸酶活性高。细菌群落结构随时间变化而不同，而四种处理之间的差异很小，这表明它主要受生物膜的定殖阶段影响，而不是磷的可利用性。总之，这些结果表明，生物膜的发育受磷的可利用性和/或定殖阶段的影响，从而决定了生物膜在覆盖水中的作用。
