Changes in bacterial community metabolism and composition during the degradation of dissolved organic matter from the jellyfish Aurelia aurita in a Mediterranean coastal lagoon
Changes in bacterial community metabolism and composition during the degradation of dissolved organic matter from the jellyfish Aurelia aurita in a Mediterranean coastal lagoon
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DOI：
10.1007/s11356-014-3848-x
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发表时间：
2015-09-01
影响因子：
5.8
通讯作者：
Joux, Fabien
中科院分区：
文献类型：
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作者：
Blanchet, Marine;Pringault, Olivier;Joux, Fabien
在过去几十年中，在许多河口和沿海生态系统中观察到胶状浮游生物暴发的空间增加和时间变化。这些水华对海洋生态系统功能的影响，特别是对异养细菌动态的影响仍不清楚。在微宇宙中对地中海沿岸泻湖细菌群落对添加水母溶解有机质(DOM)的响应进行了22天的评估(8 L)，相当于溶解有机碳(DOC)的增加1.4%。这种材料的高生物利用度导致(I)从水母中迅速矿化DOC和溶解的有机氮，(Ii)在水柱中积累高浓度的铵和正磷酸盐。水母的DOM在前2天极大地刺激异养原核生物的产生和呼吸速率；然后，这些活性持续下降，直到实验结束时在对照微宇宙(仅限于泻湖水)中测得的活性。细菌生长效率保持在20%以下，说明大部分DOM被呼吸，一小部分被引导到生物质生产。细菌多样性的变化通过部分细菌16S rRNA基因的标签焦磷酸测序、DNA指纹和培养方法进行评估。虽然对照微观世界中的细菌多样性在实验过程中变化不大，但水母中添加的DOM诱导了分离出的假交替单胞菌和弧菌的快速生长。9d后，细菌群落以拟杆菌为主，更适合代谢高相对分子质量的DOM。在实验结束时，细菌群落向更高比例的甲型变形杆菌转移。在添加了来自水母的DOM后，细菌群落的新陈代谢功能的弹性高于多样性，这表明水母水华可以诱导沿海泻湖细菌群落结构的持久变化。
Spatial increases and temporal shifts in outbreaks of gelatinous plankton have been observed over the past several decades in many estuarine and coastal ecosystems. The effects of these blooms on marine ecosystem functioning and particularly on the dynamics of the heterotrophic bacteria are still unclear. The response of the bacterial community from a Mediterranean coastal lagoon to the addition of dissolved organic matter (DOM) from the jellyfish Aurelia aurita, corresponding to an enrichment of dissolved organic carbon (DOC) by 1.4, was assessed for 22 days in microcosms (8 l). The high bioavailability of this material led to (i) a rapid mineralization of the DOC and dissolved organic nitrogen from the jellyfish and (ii) the accumulation of high concentrations of ammonium and orthophosphate in the water column. DOM from jellyfish greatly stimulated heterotrophic prokaryotic production and respiration rates during the first 2 days; then, these activities showed a continuous decay until reaching those measured in the control microcosms (lagoon water only) at the end of the experiment. Bacterial growth efficiency remained below 20 %, indicating that most of the DOM was respired and a minor part was channeled to biomass production. Changes in bacterial diversity were assessed by tag pyrosequencing of partial bacterial 16S rRNA genes, DNA fingerprints, and a cultivation approach. While bacterial diversity in control microcosms showed little changes during the experiment, the addition of DOM from the jellyfish induced a rapid growth of Pseudoalteromonas and Vibrio species that were isolated. After 9 days, the bacterial community was dominated by Bacteroidetes, which appeared more adapted to metabolize high-molecular-weight DOM. At the end of the experiment, the bacterial community shifted toward a higher proportion of Alphaproteobacteria. Resilience of the bacterial community after the addition of DOM from the jellyfish was higher for metabolic functions than diversity, suggesting that jellyfish blooms can induce durable changes in the bacterial community structure in coastal lagoons.