Sediment Ecology Research Group, Scottish Oceans Institute, School of Biology, University of St Andrews, East Sands, St Andrews, United Kingdom.
Coastal Research Group, Department of Zoology and Entomology, Rhodes University, Makhanda, South Africa.
PLoS One. 2021 Feb 19;16(2):e0240952. doi: 10.1371/journal.pone.0240952. eCollection 2021.
Intertidal systems are complex and dynamic environments with many interacting factors influencing biochemical characteristics and microbial communities. One key factor are the actions of resident fauna, many of which are regarded as ecosystem engineers because of their bioturbation, bioirrigation and sediment stabilising activities. The purpose of this investigation was to elucidate the evolutionary implications of the ecosystem engineering process by identifying, if any, aspects that act as selection pressures upon microbial communities. A mesocosm study was performed using the well characterised intertidal ecosystem engineers Corophium volutator, Hediste diversicolor, and microphytobenthos, in addition to manual turbation of sediments to compare effects of bioturbation, bioirrigation and stabilisation. A range of sediment functions and biogeochemical gradients were measured in conjunction with 16S rRNA sequencing and diatom taxonomy, with downstream bacterial metagenome function prediction, to identify selection pressures that incited change to microbial community composition and function. Bacterial communities were predominantly Proteobacteria, with the relative abundance of Bacteroidetes, Alphaproteobacteria and Verrucomicrobia being partially displaced by Deltaproteobacteria, Acidobacteria and Chloroflexi as dissolved oxygen concentration and redox potential decreased. Bacterial community composition was driven strongly by biogeochemistry; surface communities were affected by a combination of sediment functions and overlying water turbidity, and subsurface communities by biogeochemical gradients driven by sediment reworking. Diatom communities were dominated by Nitzschia laevis and Achnanthes sp., and assemblage composition was influenced by overlying water turbidity (manual or biogenic) rather than direct infaunal influences such as grazing.
潮间带系统是复杂且动态的环境，有许多相互作用的因素影响生物化学特性和微生物群落。其中一个关键因素是居住动物群的作用，其中许多动物被认为是生态系统工程师，因为它们的生物搅动、生物灌溉和沉积物稳定活动。本研究的目的是通过确定是否有任何方面对微生物群落施加选择压力，阐明生态系统工程过程的进化意义。使用特征明确的潮间带生态系统工程师——卷壳 Corophium volutator、多毛 Hediste diversicolor 和微藻床——以及手动搅动沉积物，进行了一个中观系统研究，以比较生物搅动、生物灌溉和稳定化的影响。结合 16S rRNA 测序和硅藻分类学，测量了一系列沉积物功能和生物地球化学梯度，并对细菌宏基因组功能进行了预测，以确定促使微生物群落组成和功能发生变化的选择压力。细菌群落主要为变形菌门，而拟杆菌门、α变形菌门和疣微菌门的相对丰度部分被δ变形菌门、酸杆菌门和绿弯菌门取代，随着溶解氧浓度和氧化还原电位的降低。细菌群落组成受生物地球化学的强烈驱动；表层群落受沉积物功能和上覆水浊度的综合影响，而次表层群落则受由沉积物再作用驱动的生物地球化学梯度的影响。硅藻群落主要由海链藻和小环藻组成，群落组成受上覆水浊度（手动或生物源）的影响，而不是直接的底栖动物影响，如摄食。
