小柯机器人

美国毕格罗海洋科学实验室Ramunas Stepanauskas团队近期取得重要工作进展，他们研究发现了海洋原核浮游生物呼吸速率和丰度的解耦。相关研究成果2022年12月7日在线发表于《自然》杂志上。

据介绍，海洋和大气中CO₂的交换很大程度上取决于海洋微生物光合作用和呼吸作用之间的平衡。尽管海洋浮游细菌和古细菌（原核浮游生物）在分类和代谢方面存在巨大差异，但它们的呼吸通常被大量测量，在全球生物地球化学模型中被视为“黑箱”，这限制了人们对全球碳循环机制的理解。

使用一种综合表型分析和单个微生物细胞的基因组测序技术，研究人员表明，细胞特定呼吸速率在原核浮游生物属之间的差异超过1000倍。大多数呼吸由原核浮游生物的少数成员进行（包括Roseobacter集群），而最常见谱系（包括Pelagibacter和SAR86）的细胞具有极低呼吸率。呼吸速率与谱系间丰度的脱钩、Pelagibacter和SAR86细胞中变形菌视紫红质转录物计数的增加以及SAR86夜间呼吸的增加，这些现象表明，基于变形菌视紫红质的光合作用可能构成原核浮游生物的一个重要能量来源，并可能提高生长效率。

总之，结果表明，原核浮游生物对呼吸和浮游植物来源的有机碳再矿化为CO₂的能量需求和生长的依赖可能比通常假设的要低，并且在不同谱系中存在差异。

附：英文原文

Title: Decoupling of respiration rates and abundance in marine prokaryoplankton

Author: Munson-McGee, Jacob H., Lindsay, Melody R., Sintes, Eva, Brown, Julia M., DAngelo, Timothy, Brown, Joe, Lubelczyk, Laura C., Tomko, Paxton, Emerson, David, Orcutt, Beth N., Poulton, Nicole J., Herndl, Gerhard J., Stepanauskas, Ramunas

Issue&Volume: 2022-12-07

Abstract: The ocean–atmosphere exchange of CO2 largely depends on the balance between marine microbial photosynthesis and respiration. Despite vast taxonomic and metabolic diversity among marine planktonic bacteria and archaea (prokaryoplankton)1,2,3, their respiration usually is measured in bulk and treated as a ‘black box’ in global biogeochemical models4; this limits the mechanistic understanding of the global carbon cycle. Here, using a technology for integrated phenotype analyses and genomic sequencing of individual microbial cells, we show that cell-specific respiration rates differ by more than 1,000× among prokaryoplankton genera. The majority of respiration was found to be performed by minority members of prokaryoplankton (including the Roseobacter cluster), whereas cells of the most prevalent lineages (including Pelagibacter and SAR86) had extremely low respiration rates. The decoupling of respiration rates from abundance among lineages, elevated counts of proteorhodopsin transcripts in Pelagibacter and SAR86 cells and elevated respiration of SAR86 at night indicate that proteorhodopsin-based phototrophy3,5,6,7 probably constitutes an important source of energy to prokaryoplankton and may increase growth efficiency. These findings suggest that the dependence of prokaryoplankton on respiration and remineralization of phytoplankton-derived organic carbon into CO2 for its energy demands and growth may be lower than commonly assumed and variable among lineages.

DOI: 10.1038/s41586-022-05505-3

Source: https://www.nature.com/articles/s41586-022-05505-3

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
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