Mestre Mireia, Borrull Encarna, Sala MMontserrat, Gasol Josep M
Department of Marine Biology and Oceanography, Institut de Ciències del Mar, CSIC. Barcelona, Catalunya, Spain.
ISME J. 2017 Apr;11(4):999-1010. doi: 10.1038/ismej.2016.166. Epub 2017 Jan 3.
Depending on their relationship with the pelagic particulate matter, planktonic prokaryotes have traditionally been classified into two types of communities: free-living (FL) or attached (ATT) to particles, and are generally separated using only one pore-size filter in a differential filtration. Nonetheless, particulate matter in the oceans appears in a continuum of sizes. Here we separated this continuum into six discrete size-fractions, from 0.2 to 200 μm, and described the prokaryotes associated to each of them. Each size-fraction presented different bacterial communities, with a range of 23-42% of unique (OTUs) in each size-fraction, supporting the idea that they contained distinct types of particles. An increase in richness was observed from the smallest to the largest size-fractions, suggesting that increasingly larger particles contributed new niches. Our results show that a multiple size-fractionation provides a more exhaustive description of the bacterial diversity and community structure than the use of only one filter. In addition, and based on our results, we propose an alternative to the dichotomy of FL or ATT lifestyles, in which we differentiate the taxonomic groups with preference for the smaller fractions, those that do not show preferences for small or large fractions, and those that preferentially appear in larger fractions.
根据浮游原核生物与海洋颗粒物质的关系，传统上它们被分为两类群落：自由生活型（FL）或附着于颗粒型（ATT），并且通常在差异过滤中仅使用一种孔径的滤膜来区分。然而，海洋中的颗粒物质呈现出连续的大小范围。在这里，我们将这个连续体分为六个离散的大小分级，从0.2到200μm，并描述了与每个分级相关的原核生物。每个大小分级都呈现出不同的细菌群落，每个大小分级中独特（OTU）的比例在23%至42%之间，这支持了它们包含不同类型颗粒的观点。从最小到最大的大小分级中观察到丰富度增加，这表明越来越大的颗粒提供了新的生态位。我们的结果表明，与仅使用一种滤膜相比，多大小分级能更详尽地描述细菌多样性和群落结构。此外，基于我们的结果，我们提出了一种替代自由生活型或附着型生活方式二分法的方法，在这种方法中，我们区分出偏好较小分级的分类群、对小分级或大分级没有偏好的分类群，以及优先出现在较大分级中的分类群。
