Synechococcus accounts for a considerable proportion of oceanic carbon fixation and has close relation with heterotrophic bacteria at sub-micrometre scales. However, the relationship between Synechococcus and heterotrophic bacteria and their impacts on oceanic carbon flow is not well understood. Here, we separately co-cultured the heterotrophic bacterial community with two different axenic Synechococcus strains, i.e. Synechococcus sp. PCC7002 and Synechococcus sp. CCMP1334. The dissolved organic carbon (DOC) released by Synechococcus promoted the rapid growth of heterotrophic bacteria. Due in part to the slight differences in the Synechococcus-derived DOC composition, the starting heterotrophic bacterial community was reshaped by the two Synechococcus strains into significantly divergent community structures, suggesting that different heterotrophic bacterial communities may gather around different Synechococcus strains and interact with each other in the oceans. Interestingly, the two Synechococcus strains also released some very stable humic-like DOC components that resisted use by heterotrophic bacteria and were gradually accumulated in seawater, implying that in addition to photosynthetic carbon fixation, Synechococcus may also play an important role in long-term ocean carbon sequestration by producing relatively recalcitrant DOC. Moreover, the interactions of Synechococcus and the heterotrophic bacterial communities could increase aggregate formation and particle sinking, which can likely enhance the contribution of Synechococcus to the magnitude of the sinking biological carbon pump in the oceans.

聚藻占海洋固碳的相当大的比例，并具有在亚微米尺度异养细菌密切相关。然而，之间的关系聚球蓝细菌对海洋碳流和异养细菌及其影响还不是很清楚。在这里，我们分别共培养异养细菌群落与两个不同的无菌聚藻株，即聚球藻。PCC7002和Synechococcus sp。CCMP1334。Synechococcus释放的溶解有机碳（DOC）促进了异养细菌的快速生长。部分归因于Synechococcus中的细微差异来源于DOC的组成，起始的异养细菌群落被两个Synchococcus菌株重塑成明显不同的群落结构，表明不同的异养细菌群落可能聚集在不同的Syechococcus菌株周围并在海洋中相互作用。有趣的是，这两个Synocococcus菌株还释放了一些非常稳定的腐殖质样DOC成分，这些成分抵抗异养细菌的使用并逐渐积聚在海水中，这意味着Synechococcus除光合碳固定外，在长期海洋中也可能起重要作用。通过产生相对顽固的DOC来固碳。而且，聚球藻和异养细菌群落可以增加总的形成和颗粒下沉，从而可能提高的贡献聚球藻在海洋下沉生物碳泵的幅度。