Warming treatments shift the temporal dynamics of diversity and composition of bacteria in wild blueberry soils

Soil bacterial communities are a crucial biological indicator of soil health and crop performance; however, their response to climate change remains poorly understood. Wild blueberry farms are experiencing unprecedented temperature changes, which may exacerbate microbial responses and potentially harm the crop. Here, we aimed to elucidate the response of bacterial communities in wild blueberry fields to warming.

We employed passive and active open-top chambers to simulate climate warming scenarios, which elevated atmospheric temperatures by 1.2 and 3.3°C, respectively. Soils in the active warming treatment exhibited significantly lower water content than in ambient conditions. Overall soil bacterial diversity and richness under the warming (passive and active) treatments and ambient controls did not demonstrate significant differences after 2 years of warming. However, we found significantly higher bacterial evenness and diversity under warming treatments in the early growing season (June). Our study found pronounced seasonal shifts in the evenness and diversity of bacteria in wild blueberry soils, suggesting that the variation in bacterial community structure may be more influenced by seasonal changes in temperature and plant activity than by warming treatments.

Our study reveals the limited impact of warming on overall soil bacterial diversity in a temperate crop, but the seasonal dynamics of bacterial diversity and composition are sensitive to warming. The increased bacterial evenness and diversity under warming treatments in June could be attributed to advanced plant phenology, indicating a potential future shift in seasonal dynamics of bacterial activity under global warming.