Symbiotic causal network of seagrass-bacteria-algae-diatoms interactions

TL;DR

This study investigates the complex symbiotic and metabolic interactions in seagrass habitats across Japan, revealing key relationships that support healthy ecosystems and inform conservation efforts.

Contribution

It provides a detailed analysis of the structural and metabolic characteristics of seagrass-associated microbial communities across multiple regions.

Findings

Seagrasses maintain positive associations with cable bacteria, nitrogen-cycling bacteria, and coral algae.

Seagrass growth activates nitrogen metabolism and reduces methanogenesis.

Symbiotic relationships are crucial for seagrass health and blue carbon storage.

Abstract

Seagrass meadows contribute to the conservation of marine ecosystems, reduction in global warming impacts and pathogen controls. However, the decline in seagrass habitats due to environmental loads has become an urgent global issue. One way to address this issue is to better understand healthy seagrass habitats. Here, we estimate the structural characteristics of symbiotic and metabolic systems in sediments from eight coastal regions of Japan, with each region containing both seagrass-covered areas and adjacent unvegetated areas. Notably, seagrasses commonly maintain a balanced symbiotic relationship characterized by a positive association with cable bacteria (Desulfobulbaceae), nitrogen-cycling bacteria (Hyphomonadaceae), and coral algae (Corallinophycidae) and a negative association with diatoms (Diatomea). Furthermore, seagrass growth conditions influence metabolic pathways by activating nitrogen-related metabolism while attenuating methanogenesis. Our findings highlight the crucial roles of marine plants and their symbiotic systems in ensuring environmental conservation within the context of blue carbon storage across environmental gradients.