Impact of protist grazing on a key bacterial group for biogeochemical cycling in Baltic Sea pelagic oxic/anoxic interfaces
Impact of protist grazing on a key bacterial group for biogeochemical cycling in Baltic Sea pelagic oxic/anoxic interfaces
复制标题
DOI：
10.1111/1462-2920.12078
复制
发表时间：
2013-05-01
影响因子：
5.1
通讯作者：
Juergens, Klaus
中科院分区：
文献类型：
--
作者：
Anderson, Ruth;Wylezich, Claudia;Juergens, Klaus
含氧水团和缺氧水团（氧化还原素）之间的屏障区拥有高度活跃的原核生物群落，在生物地球化学循环中发挥重要作用。在波罗的海中上层氧化还原菌中，硫单胞菌属（GD17 亚组）的 Epsilonproteobacteria 已被证明主导化能自养反硝化作用。然而，人们对影响该原核生物群的损失过程知之甚少。在本研究中，利用捕食者排除试验和对培养的代表性硫单胞菌菌株 GD1 进行细菌修正，确定了波罗的海氧化还原素的低氧和氧/硫化氢界面深度对硫单胞菌亚群 GD17 的原生生物放牧影响。此外，还通过 RNA 稳定同位素探测 (RNA-SIP) 鉴定了主要食菌动物。天然硫化单胞菌亚群 GD17 种群在氧/硫化氢界面条件下强劲生长（倍增时间：11.5 天），但原生生物放牧可能会消耗每天完整的新细胞产量。在低氧样品中，几乎没有观察到硫单胞菌亚群 GD17 的生长。 RNA-SIP 鉴定了五种活跃的食草动物，属于典型的氧化还原纤毛虫（Oligohymenophorea、Prostomatea）和全球广泛分布的海洋鞭毛虫类群（MAST-4、Chrysophyta、Cercozoa）。总的来说，我们首次证明原生生物放牧可以控制有氧/缺氧界面的化能自养关键角色的生长，并可能控制其垂直分布。
Barrier zones between oxic and anoxic water masses (redoxclines) host highly active prokaryotic communities with important roles in biogeochemical cycling. In Baltic Sea pelagic redoxclines, Epsilonproteobacteria of the genus Sulfurimonas (subgroup GD17) have been shown to dominate chemoautotrophic denitrification. However, little is known on the loss processes affecting this prokaryotic group. In the present study, the protist grazing impact on the Sulfurimonas subgroup GD17 was determined for suboxic and oxygen/hydrogen sulphide interface depths of Baltic Sea redoxclines, using predator exclusion assays and bacterial amendment with the cultured representative Sulfurimonas gotlandica' strain GD1. Additionally, the principal bacterivores were identified by RNA-Stable Isotope Probing (RNA-SIP). The natural Sulfurimonas subgroup GD17 population grew strongly under oxygen/hydrogen sulphide interface conditions (doubling time: 11.5 days), but protist grazing could consume the complete new cell production per day. In suboxic samples, little or no growth of Sulfurimonas subgroup GD17 was observed. RNA-SIP identified five active grazers, belonging to typical redoxcline ciliates (Oligohymenophorea, Prostomatea) and globally widespread marine flagellate groups (MAST-4, Chrysophyta, Cercozoa). Overall, we demonstrate for the first time that protist grazing can control the growth, and potentially the vertical distribution, of a chemolithoautotrophic key-player of oxic/anoxic interfaces.