The digestive tract of animals harbors microbiota important for the host’s fitness and performance. The interaction between digestive tract bacteria and soil animal hosts is still poorly explored despite the importance of soil fauna for ecosystem processes. In this study, we investigated the interactions between the bacterial communities from the digestive tract of the litter-feeding, semi-terrestrial crustacean Orchestia gammarellus and those obtained from the environment; these organisms thrive in, i.e., soil and plant litter from salt marshes. We hypothesized that elevation is an important driver of soil and litter bacterial communities, which indirectly (via ingested soil and litter bacteria) influences the bacterial communities in the digestive tract of O. gammarellus. Indeed, our results revealed that elevation modulated soil and litter bacterial community composition along with soil organic matter content and the C:N ratio. Soil and plant litter differed in alpha diversity indexes (richness and diversity), and in the case of plant litter, both indexes increased with elevation. In contrast, elevation did not affect the composition of bacterial communities associated with O. gammarellus’ digestive tract, suggesting selection by the host, despite the fact that a large component of the bacterial community was also detected in external sources. Importantly, Ca. Bacilloplasma and Vibrio were highly prevalent and abundant in the host. The taxonomic comparison of Ca. Bacilloplasma amplicon sequence variants across the host at different elevations suggested a phylogenetic divergence due to host habitat (i.e., marine or semi-terrestrial), thus supporting their potential functional role in the animal physiology. Our study sheds light on the influence of the environment on soil animal–bacteria interactions and provides insights into the resilience of the O. gammarellus–associated bacteria to increased flooding frequency.
Bibliographical noteFunding Information:
We thank Tom Jensma, Nadia Hijner, Melanie Kuilder, and Jurgen van Hal for the field and technical support. We also thank Nelly D. Eck, Jolanda K. Brons, Laura Govers, and J.J. Hogendorf for the technical assistance. We are grateful to Ruth Howison for the inundation frequency and successional stage data. We acknowledge the ?Nederlandse Vereniging voor Natuurmonumenten? for granting us access to the salt marsh. We would like to thank the Center for Information Technology of the University of Groningen for their support and for providing access to the Peregrine high-performance computing cluster. We thank the anonymous reviewers whose comments helped to improve the quality of the manuscript.
EGH was supported by the Consejo Nacional de Ciencia y Tecnologia (CONACyT) (scholarship number 484425) and University of Groningen scholarship program. This work is part of the research program of RvO with project number NWO ALWOP.219.00179028, which is (partly) financed by the Dutch Research Council (NWO). MPB was financially supported by a fellowship of the Uyttenboogaart-Eliasen Foundation.
© 2021, The Author(s).
- Ecosystem engineer
- Gut microbiome
- Orchestia gammarellus
- Salt marsh elevation
- Soil fauna