[POS] Ecology and Enviromment

[POS-41] High-resolution temporal dynamics of diurnal fluctuations in the mouse gut microbiome

*Rie Maskawa¹, Hideki Takayasu^1,2, Lena Takayasu^3,2, Rina Kurokawa², Hiroaki Masuoka², Tanzila Islam¹, Yu Yoshikawa¹, Wataru Suda², Misako Takayasu¹ (1. Institute of Science Tokyo (Japan), 2. RIKEN IMS (Japan), 3. Cornell University (United States of America))

Keywords:

Microbiome

Although the gut microbiota is generally considered to be a stable ecosystem under homeostatic conditions, how it fluctuates within a single day remains largely unknown. Quantifying the degree of microbial variation at each time point throughout the day is essential for understanding both inter- and intra-individual variability of the microbiota. To address this, we developed an automated fecal sampling system capable of hourly collection and applied it to five mice over four consecutive days, generating a high-resolution time-series dataset. Defecation patterns exhibited a distinct circadian rhythm, while the gut microbial community showed both approximately 1-day periodicity and slow multi-day trends. In addition, the growth rates of individual species exhibited negative lag-1 autocorrelation, indicating autoregressive behavior. Applying a vector autoregressive model to these growth rates, the temporal variation was accurately explained by time-lagged interactions. These results demonstrate that hourly-resolution data can capture the temporal scales of microbial interactions and reveal structured, non-random diurnal dynamics.