Manila clams microbiome biodiversity and its association with seasonal and environmental variables.

The vital role of host microbiota in shaping the development and resilience of organisms is now widely recognized. With rising global populations placing a growing demand on food security, aquaculture is increasingly crucial for sustainable food production. To further explore this, we investigated the influence of the North Adriatic Sea's unique and challenging environment on the tissue-specific microbiota of clams. This fragile ecosystem faces mounting environmental pressures, making it crucial to understand how these factors influence the clams-microbiota relationship, in order to optimize clam health and resilience within aquaculture practices. To address this knowledge gap, we employed a bioinformatics approach to analyze the composition and function of microbiota across clam tissues (gills and digestive gland) in five sites throughout summer and winter 2019. This approach allowed for a detailed examination of the complex bacterial communities within the clams. Our findings revealed significant variations in the microbiota composition across both tissues and seasons. The digestive gland, in particular, exhibited the most diverse and balanced bacterial communities, also displaying the clearest seasonal shift between summer and winter. Additionally, differential abundance analysis revealed that sites affected by pollution harbored distinct microbiota compared to cleaner areas. Notably, the presence of the potential pathogenic Vibrio was observed in polluted areas during summer, while Rickettsiella was found to be abundant in the digestive gland during winter. This study provides valuable insights into the interplay between environmental factors, tissue specificity, and the clam-microbiota relationship within the Venice Lagoon's challenging environment. This knowledge can be instrumental in developing sustainable aquaculture practices that promote healthy and resilient clam populations, ultimately contributing to global food security.