Data_Sheet_1_Microbiomes of the Enteropneust, Saccoglossus bromophenolosus, and Associated Marine Intertidal Sediments of Cod Cove, Maine.docx

Enteropneusts are widely distributed marine invertebrates that accumulate high concentrations of halogenated aromatics. Some of these compounds affect benthic biogeochemistery (e.g., denitrification and ammonia oxidation), but little is known about interactions between enteropneusts and their associated microbial communities. Even less is known about enteropneust host-microbe relationships in the digestive tract. More generally, microbial community composition and diversity in intertidal sediments have received little attention. In this study, high throughput sequence analyses of 16S rRNA genes extracted from microbial communities associated with sediment-free whole individuals of Saccoglossus bromophenolosus and freshly excreted S. bromophenolosus gut sediments revealed a potential Spirochaete symbiont that was abundant, present in gut sediment, but absent in other sediments. Relative to surface sediments, gut communities also revealed evidence for selective losses of some groups and blooms of others, especially Colwellia, Photobacterium, Pseudoalteromonas, and Vibrio. After deposition, gut sediment communities rapidly resembled those of surface sediments. Although hierarchical cluster analysis and Linear Discriminant Analysis Effect Size (LEfSe) differentiated among burrow walls of S. bromophenolosus and a polychaete, Alitta virens, as well as between surface and sub-surface sediments, most operational taxonomic units (OTUs) were shared, with differences largely occurring in relative abundances. This suggests that sediment mixing through bioturbation might act to homogenize community composition, while species-specific impacts by infauna might alter local population abundances. Although Cod Cove is a relatively isolated intertidal system, microbial community members included groups with cosmopolitan distributions and roles in sulfur cycling, e.g., Gammaproteobacteria BD7 and Sva0071, as well as novel OTUs representing a large number of phyla.

环节动物门的无脊椎动物 Enteropneusts 在海洋中广泛分布，体内累积了高浓度的卤代芳香族化合物。其中部分化合物会影响底栖生物地球化学过程（例如，反硝化和氨氧化），然而关于 Enteropneusts 与其相关微生物群落的相互作用知之甚少。尤其是关于 Enteropneusts 在消化道的宿主-微生物关系，了解更少。更普遍的是，潮间带沉积物中的微生物群落组成和多样性鲜受关注。在本研究中，通过对来自无沉积物完整个体 Saccoglossus bromophenolosus 和新鲜排泄物 S. bromophenolosus 肠道沉积物的 16S rRNA 基因进行高通量测序分析，揭示了一种潜在的螺旋体共生体，该共生体在肠道沉积物中丰富，但在其他沉积物中不存在。与表层沉积物相比，肠道群落显示出某些群落的选择性减少和其他群落的增殖现象，尤其是 Colwellia、Photobacterium、Pseudoalteromonas 和 Vibrio。沉积后，肠道沉积物群落迅速与表层沉积物群落相似。尽管层次聚类分析和线性判别分析效应大小（LEfSe）将 S. bromophenolosus 的洞穴壁与多毛类动物 Alitta virens 以及表层和亚表层沉积物区分开来，但大多数操作分类单元（OTUs）是共有的，差异主要存在于相对丰度上。这表明通过生物扰动作用，沉积物的混合可能有助于群落组成的均质化，而土著动物对特定物种的影响可能改变局部种群丰度。尽管科德湾是一个相对隔离的潮间带系统，但微生物群落成员包括具有全球分布和硫循环作用（例如，Gammaproteobacteria BD7 和 Sva0071）的群体，以及代表大量门的新型 OTUs。