Host Compartmentalization and Biogeography Shape the Bacterial and Fungal Communities of Papua New Guinea Mangroves

Coastal marine ecosystems, including mangroves, are important providers of ecosystem functions and services. However, such ecosystems are in steep decline, especially in Southeast Asia and the Pacific Region. Mangroves exist in intertidal areas where environmental conditions can be highly variable, particularly between dry above-ground and submerged- or below-ground structures. The microbiomes within these structures are crucial in the maintenance of proper functioning and resilience or adaptation to anthropogenic stressors. This study provides the first overview of the mangrove microbiome across the highly biodiverse but understudied habitats of Papua New Guinea. We identify a shared core microbiome comprising of 31 bacterial and fungal taxa for Avicennia alba and Sonneratia alba . These communities are shaped by host section, site, and host species. Moreover, a list of 13 and 11 taxa from within the core microbiome is identified to drive variation between the environmental (sediment) and mangrove microbiomes, and between different mangrove plant sections, respectively. These can serve as starting points to investigate potentially important microbial members within mangroves and further our understanding of mangrove-microbe interactions, contributing to improved mangrove restoration project outcomes.