Assembly processes underlying bacterial community differentiation among geographically close mangrove forests

Habitat- and lifestyle-dependent structural and functional characteristics of viruses in mangrove wetlands of different functional zonings

Mangrove wetlands, as one of the natural ecosystems with the most ecological services, have garnered widespread attention about their microbial driven biogeochemical cycling. Urbanization have led to different spatial patterns of environmental conditions and microbial communities in mangroves. However, viruses, as the pivotal drivers of biogeochemical cycling in mangroves, remain inadequately explored in terms of how their ecological potential and complex interactions with host respond to functional zonings. To address this knowledge gap, we conducted a comprehensive investigation on the structural and functional properties of temperate and lytic viruses in mangrove wetlands from different functional zonings by jointly using high-throughput sequencing, prokaryotic and viral metagenomics. Multiple environmental factors were found to significantly influence the taxonomic and functional composition, as well as lysogen-lysis decision-making of mangrove viruses. Furthermore, enriched auxiliary metabolic genes (AMGs) involved in methane, nitrogen and sulfur metabolism, and heavy metal resistance were unveiled in mangrove viruses, whose community composition was closely related to lifestyle and host. The virus-host pairs with different lifestyles were also discovered to react to environmental changes in different ways, which provided an empirical evidence for how virus and bacteria dynamics were specific to viral lifestyles in nature. This study expands our comprehension of the intricate interactions among virus, prokaryotic host and the environment in mangrove wetlands from multiple perspectives, including viral lifestyles, virus-host interactions, and habitat dependence. Importantly, it provides a new ecological perspective on how mangrove viruses are adapted to the stress posed by urbanization.

Uncovering potential mangrove microbial bioindicators to assess urban and agricultural pressures on Martinique island in the eastern Caribbean Sea

Martinique's mangroves, which cover 1.85 ha of the island (<0.1 % of the total area), are considerably vulnerable to local urban, agricultural, and industrial pollutants. Unlike for temperate ecosystems, there are limited indicators that can be used to assess the anthropogenic pressures on mangroves. This study investigated four stations on Martinique Island, with each being subject to varying anthropogenic pressures. An analysis of mangrove sediment cores approximately 18 cm in depth revealed two primary types of pressures on Martinique mangroves: (i) an enrichment in organic matter in the two stations within the highly urbanized bay of Fort-de-France and (ii) agricultural pressure observed in the four studied mangrove stations. This pressure was characterized by contamination, exceeding the regulatory thresholds, with dieldrin, total DDT, and metals (As, Cu and Ni) found in phytosanitary products. The mangroves of Martinique are subjected to varying degrees of anthropogenic pressure, but all are subjected to contamination by organochlorine pesticides. Mangroves within the bay of Fort-de-France experience notably higher pressures compared to those in the island's northern and southern regions. In these contexts, the microbial communities exhibited distinct responses. The microbial biomass and the abundance of bacteria and archaea were higher in the two less-impacted stations, while in the mangrove of Fort-de-France, various phyla typically associated with polluted environments were more prevalent. These differences in the microbiota composition led to the identification of 65 taxa, including Acanthopleuribacteraceae, Spirochaetaceae, and Pirellulaceae, that could potentially serve as indicators of an anthropogenic influence on the mangrove sediments of Martinique Island.

The function and keystone microbiota in typical habitats under the influence of anthropogenic activities in Baiyangdian Lake

Microbe is an essential driver in regulating the biochemical cycles of carbon, nitrogen, and sulfur. In freshwater lake, microbial communities and functions are influenced by multiple factors, especially anthropogenic activities. Baiyangdian Lake consisted of various habitats, and was frequently interfered with human activities. In this study, 16 S rRNA sequencing and metagenomic sequencing were performed to characterize the microbial communities, determine keystone taxa and reveal dominated metabolic functions in typical habitats in Baiyangdian Lake. The results showed that the diversity of microbial community was significantly higher in sediment compared with corresponding water sample. Microbial community showed strong spatial heterogeneity in sediment, and temporal heterogeneity in water. As for different habitats, significantly higher alpha diversity was observed in ecotone, where the interference of human activities was relatively weak. The shared OTUs were distinguished from the keystone taxa, which indicated the uniqueness of microbiota in different ecological habitat. Moreover, the interactions of microbial in ecological restoration area (abandoned fish pond) were relatively simple, suggesting that this ecosystem was relatively fragile compared with others. Based on the metagenomic sequencing, we recognized that the canal, open water, and abandoned fish pond were beneficial for methanogenic and the ecotone might be a hot zone for the oxidation of methane. Notably, most of the microbes that participated in these predominant metabolisms were unclassified, which indicated the hug potential for exploring functional microorganisms in Baiyangdian Lake. This study provided a comprehensive understanding of the ecology characteristics of microbiota in habitats undergoing various human interference in Baiyangdian Lake.