phytoplankton exudate utilization by bacteria. exudate utilization

We adressed the following research questions: i) how is the bacterial utilization of phytoplankton derived DOC affected by inorganic nutrients? ii) how specific is the bacterial utilization of phytoplankton exudates between two contrasting environments (coastal vs open-ocean)? iii) how specific is the bacterial utilization of exudates from different phytoplankton speciesiv) how is the succession of bacterial communities over time with exudates provided by different phytoplanktonTo test this, we performed 3 experiments:1. Prochlorococcus exudate additions to a coastal bacterial community with and without additions of inorganic nutrients. Sequencing at t0 and after 24h.2. exudate additions of Prochlorococcus and Skeletonema to coastal bacterial communities. Sequencing at t0, at after 6, 24, 48, and 72 h.3. Prochlorococcus exudate additions to a open-ocean bacterial community with and without additions of inorganic nutrients. Sequencing at t0 and after 24h.

本研究针对以下四项研究问题展开探讨：i) 浮游植物来源的溶解性有机碳（dissolved organic carbon, DOC）的细菌利用过程如何受无机营养盐调控？ii) 在沿岸海域与开阔大洋这两种截然不同的生境中，细菌对浮游植物渗出物的利用特异性如何？iii) 不同浮游植物物种的渗出物，其被细菌利用的特异性存在何种差异？iv) 当添加不同浮游植物来源的渗出物时，细菌群落的时间演替规律如何？为验证上述研究问题，本研究开展了3组实验：1. 向沿岸海域细菌群落添加原绿球藻（Prochlorococcus）渗出物，并设置添加与不添加无机营养盐两组处理，分别在初始时刻（t0）与培养24小时后进行测序。2. 向沿岸海域细菌群落分别添加原绿球藻（Prochlorococcus）与骨条藻（Skeletonema）的渗出物，分别在初始时刻（t0）、培养6、24、48及72小时后进行测序。3. 向开阔大洋细菌群落添加原绿球藻（Prochlorococcus）渗出物，并设置添加与不添加无机营养盐两组处理，分别在初始时刻（t0）与培养24小时后进行测序。