Nutrient recycling facilitates long-term stability of marine microbial phototroph-heterotroph interactions.
Nutrient recycling facilitates long-term stability of marine microbial phototroph-heterotroph interactions.
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DOI：
10.1038/nmicrobiol.2017.100
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发表时间：
2017-06-26
影响因子：
28.3
通讯作者：
Scanlan DJ
中科院分区：
文献类型：
--
作者：
Christie-Oleza JA;Sousoni D;Lloyd M;Armengaud J;Scanlan DJ
生物相互作用是海洋生态系统功能的基础，无论是通过竞争、捕食、互利共生还是共生过程。微生物的光养-异养相互作用推动了导致单个元素生物地球化学循环的引擎，对于理解和模拟全球海洋过程至关重要。不幸的是，迄今为止的研究都集中在营养丰富的培养基中指数增长的培养物上，这意味着在原位条件下这种相互作用的知识充其量是初步的。在这里，我们进行了长期的光养-异养共培养实验营养修正和自然海水条件下，这表明它不是营养物质的浓度，而是他们的循环，保持一个稳定的相互作用和动态系统。使用集球藻-Rosebrum相互作用作为模型光养-异养案例研究，我们表明，虽然集球藻是高度专业化的进行光合作用和固碳，它依赖于异养重新矿化不可避免地泄漏的有机物质，使营养物质在互惠系统中循环。从这个意义上说，我们挑战的一般信念，海洋光养生物和异养生物竞争同样稀缺的营养物质和生态位空间，而是建议这些生物更有可能受益于对方，因为他们的专业化和互补性的长期稳定状态系统的不同水平。
Biological interactions underpin the functioning of marine ecosystems, be it via competition, predation, mutualism, or symbiosis processes. Microbial phototroph-heterotroph interactions propel the engine that results in the biogeochemical cycling of individual elements and are critical for understanding and modelling global ocean processes. Unfortunately, studies thus far have focused on exponentially-growing cultures in nutrient-rich media, meaning knowledge of such interactions under in situ conditions is rudimentary at best. Here, we performed long-term phototroph-heterotroph co-culture experiments under nutrient-amended and natural seawater conditions which showed that it is not the concentration of nutrients but rather their circulation that maintains a stable interaction and a dynamic system. Using the Synechococcus-Roseobacter interaction as a model phototroph-heterotroph case study we show that whilst Synechococcus is highly specialised for carrying out photosynthesis and carbon-fixation it relies on the heterotroph to re-mineralise the inevitably leaked organic matter making nutrients circulate in a mutualistic system. In this sense we challenge the general belief that marine phototrophs and heterotrophs compete for the same scarce nutrients and niche space, but instead suggest these organisms more likely benefit from each other because of their different levels of specialization and complementarity within long-term stable-state systems.