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Abstract：
Molecular observational tools are useful for characterizing the composition and genetic endowment of microbial communities but cannot measure fluxes, which are critical for the understanding of ecosystems. To overcome these limitations, we used a mechanistic inference approach to estimate dissolved organic carbon (DOC) production and consumption by phytoplankton operational taxonomic units and heterotrophic prokaryotic amplicon sequence variants and inferred carbon fluxes between members of this microbial community from Western English Channel time-series data. Our analyses focused on phytoplankton spring and summer blooms, as well as bacteria summer blooms. In spring blooms, phytoplankton DOC production exceeds heterotrophic prokaryotic consumption, but in bacterial summer blooms heterotrophic prokaryotes consume three times more DOC than produced by the phytoplankton. This mismatch is compensated by heterotrophic prokaryotic DOC release by death, presumably from viral lysis. In both types of summer blooms, large amounts of the DOC liberated by heterotrophic prokaryotes are reused through internal recycling, with fluxes between different heterotrophic prokaryotes being at the same level as those between phytoplankton and heterotrophic prokaryotes. In context, internal recycling accounts for approximately 75% and 30% of the estimated net primary production (0.16 vs 0.22 and 0.08 vs 0.29 μmol l-1 d-1) in bacteria and phytoplankton summer blooms, respectively, and thus represents a major component of the Western English Channel carbon cycle. We have concluded that internal recycling compensates for mismatches between phytoplankton DOC production and heterotrophic prokaryotic consumption, and we encourage future analyses on aquatic carbon cycles to investigate fluxes between heterotrophic prokaryotes, specifically internal recycling.
摘要：
分子观测工具非常适合表征微生物群落的组成和遗传禀赋，但不能测量通量，这对理解生态系统至关重要。为了克服这些限制,我们使用机械推断方法来估计浮游植物操作分类单位（OTU）和异养原核扩增子序列变体（ASV）的溶解有机碳（DOC）生产和消费，并从西方英吉利海峡时间序列数据推断该微生物群落成员之间的碳通量。我们的分析重点是浮游植物春季和夏季的花朵，以及细菌夏天开花。在春天的花朵，浮游植物DOC产量超过异养原核生物消耗，但是在细菌夏季花中，异养原核生物消耗的DOC比浮游植物多3倍。这种错配是由异养原核DOC释放死亡补偿，推测来自病毒裂解。在这两种类型的夏季花朵中，异养原核生物释放的大量DOC通过内部回收再利用。,不同异养原核生物之间的通量与浮游植物和异养原核生物之间的通量处于相同的水平。语境化，内部回收约占细菌和浮游植物夏季花朵中估计的净初级产量的75％和30％（0.16vs0.22和0.08vs0.29μmoll-1d-1），分别,因此代表了西英吉利海峡碳循环的主要组成部分。我们得出的结论是，内部回收可以补偿浮游植物DOC生产与异养原核生物消耗之间的错配，我们鼓励未来对水生碳循环进行分析，以考虑异养原核生物之间的通量，特别是内部回收。
