Microbial community structure and ecology in sediments of a pristine mangrove forest

Abstract

Mangrove forests are coastal intertidal ecosystems, characterized by mangrove trees growing in slow moving saline waters, that constitute a large portion of the coastline in the tropical and subtropical regions. The dynamic water regime created by the tides results in different microhabitats in which microbial communities play an essential role in the functioning and maintenance of the mangrove ecosystem. However, little is known about the diversity of taxa within these micro-habitats and their functional roles, as only a small fraction of these organisms can be cultured in the laboratory. In this study, we characterized the microbial community present in three distinct regions of mangrove sediments from the Serinhaém estuary, part of the Atlantic Forest biome within the Environmental Protection Area of Pratigi. We sampled sediments from regions below the tidal waterline (submerged), intertidal regions (intertidal), and regions above the tidal waterline (seco). More than 85% of all the sequences in the samples belonged to 6 of 42 identified phyla: Proteobacteria (30.6%), Firmicutes (30%), Chloroflexi (8.7%), Planctomycetes (5.7%), Crenarchaeota (5.4%) and Actinobacteria (5.3%). Diversity indices show that the submerged regions of the mangrove forest exhibit the greatest diversity and richness relative to the other regions. Notably, the intertidal region has the least diversity, suggesting that the dynamics of environmental variables in this region has an important influence on microbial diversity. Furthermore, distance metrics indicate that submerged sediments are more homogeneous while the seco region exhibits greater variability between locations. Finally, we found that the most abundant microbial families in the sediments are associated with nutrient cycling consistent with the essential role of the microbiome in maintaining the health of the mangrove ecology.

Kaustia mangrovi gen. nov., sp. nov. isolated from Red Sea mangrove sediments belongs to the recently proposed Parvibaculaceae family within the order Rhizobiales

“…It has been estimated that the bacteria in mangrove sediments constitute up to 80 % of the total living biomass of these ecosystems [13][14][15][16] and play a key role in their functioning [12]. However, relatively few studies have focused on the exploration and characterization of the microbial diversity of mangrove sediments [7,10,11,13,14,[17][18][19][20][21][22][23][24][25][26][27] and the cultivable fraction of microbes therein [28][29][30][31][32][33][34]. The cultivable bacterial strains obtained from mangrove sediments include members of well-characterized genera, such as Bacillus, Halobacillus, Microbacterium, Novosphingobium, Paracoccus, Streptomyces, Thalassotalea and Vibrio [30,33,[35][36][37][38][39], and several novel genera, including Acidimangrovimonas, Mangroviflexus, Mangrovibacterium, Marisediminitalea, Mangrovicoccus, Mangrovitalea, Mangrovimonas and Zhengella [32,34,[40][41][42][43][44][45]; these data clearly conf...…”

Comparative metagenomic analysis of bacterial communities and functional profiles in urban-influenced blue carbon ecosystems

“…2a), highlights the specialized niches and potential unique functional roles these bacteria play in the seaweed ecosystem. Conversely, the mangrove ecosystem was characterized by a predominance of Firmicutes, suggesting an adaptation to the sediment-rich and potentially anaerobic conditions of mangroves (Santana et al, 2019;Chithira et al, 2021;Fernandes et al, 2022). The presence of other phyla like Proteobacteria and Actinobacteria, although in reduced abundance compared to the seaweed ecosystem, along with unique taxa such as BRC1, Gemmatimonadetes, and others (Fig.…”

Mangrovivirga cuniculi gen. nov., sp. nov., a moderately halophilic bacterium isolated from bioturbated Red Sea mangrove sediment, and proposal of the novel family Mangrovivirgaceae fam. nov.

“…Mangroves represent one of the most productive ecosystems, playing an important role in nutrient cycling and energy flow at the dynamic interface between land and sea [1, 2]. Mangrove sediments harbour an enormous microbial biomass (1×10 9 –1×10 11 cells per gram of sediment [3, 4]) rich in functional and phylogenetic diversity [5–7]. Bacteroidetes account for a significant fraction of the bacterial community ( i.e.…”

“…Mangroves represent one of the most productive ecosystems, playing an important role in nutrient cycling and energy flow at the dynamic interface between land and sea [1,2]. Mangrove sediments harbour an enormous microbial biomass (1×10 9 -1×10 11 cells per gram of sediment [3,4]) rich in functional and phylogenetic diversity [5][6][7]. Bacteroidetes account for a significant fraction of the bacterial community (i.e., 5-45 % in mangrove sediments and contiguous environmental niches such as mangrove plant tissues [6][7][8][9][10]), indicating their importance in marine ecosystems, similar to other coastal and offshore sediments, seawater and hydrothermal vents [11][12][13][14].…”