海草是复杂的底栖沿海生态系统,在有机质循环和碳固存中起着至关重要的作用。然而,人们对海草如何影响底栖细菌群落的结构和碳利用潜力知之甚少。这项研究检查了海草的单种和混合草甸中的细菌群落,并与来自Chilika的散装(无植被)沉积物进行了比较,印度沿海咸水泻湖。16SrRNA基因的高通量测序揭示了底栖细菌群落多样性差异的植被效应,composition,和丰度与散装沉积物相比。脱硫杆菌,色度,肠杆菌,梭菌,弧菌,酸性微生物是导致海草和散装沉积物之间差异的主要类群。由于沉积物中富含有机碳,海草的细菌丰度比大部分高5.94倍。与散装相比,共生网络在海草细菌群落中显示出更强的潜在相互作用和连通性。色度和酸性微生物被确定为海草细菌群落中的前两个梯形分类群,然而,Dehalococcoidales和根瘤菌是散装社区。海草和当地环境因素,即,水深,水pH值,沉积物盐度,氧化还原电位,总有机碳,可用氮气,沉积物纹理,沉积物pH值,和沉积物核心深度是底栖细菌群落组成的主要驱动因素。碳代谢谱分析表明,海草沉积物中的异养细菌在代谢上比散装细菌更具多样性和活性。碳基质的利用会,即,氨基酸,胺,羧酸,碳水化合物,聚合物,海草沉积物中的酚类化合物增强。代谢作图预测海草沉积物中硫酸盐-还原剂和N2固定代谢功能的患病率更高。总的来说,这项研究表明,海草控制底栖细菌群落组成和多样性,提高异养碳底物利用率,并在有机质循环中发挥关键作用,包括沿海沉积物中碳氢化合物和异种生物的降解。
Seagrasses are complex benthic coastal ecosystems that play a crucial role in organic matter cycling and carbon sequestration. However, little is known about how seagrasses influence the structure and carbon utilization potential of benthic bacterial communities. This study examined the bacterial communities in monospecific and mixed meadows of seagrasses and compared with bulk (unvegetated) sediments from
Chilika, a brackish water coastal lagoon of India. High-throughput sequencing of 16S rRNA genes revealed a vegetation effect in terms of differences in benthic bacterial community diversity, composition, and abundances in comparison with bulk sediments. Desulfobacterales, Chromatiales, Enterobacteriales, Clostridiales, Vibrionales, and Acidimicrobiales were major taxa that contributed to differences between seagrass and bulk sediments. Seagrasses supported ∼5.94 fold higher bacterial abundances than the bulk due to rich organic carbon stock in their sediments. Co-occurrence network demonstrated much stronger potential interactions and connectedness in seagrass bacterial communities compared to bulk. Chromatiales and Acidimicrobiales were identified as the top two keystone taxa in seagrass bacterial communities, whereas, Dehalococcoidales and Rhizobiales were in bulk communities. Seagrasses and local environmental factors, namely, water depth, water pH, sediment salinity, redox potential, total organic carbon, available nitrogen, sediment texture, sediment pH, and sediment core depth were the major drivers of benthic bacterial community composition. Carbon metabolic profiling revealed that heterotrophic bacteria in seagrass sediments were much more metabolically diverse and active than bulk. The utilization of carbon substrate guilds, namely, amino acids, amines, carboxylic acids, carbohydrates, polymers, and phenolic compounds was enhanced in seagrass sediments. Metabolic mapping predicted higher prevalence of sulfate-reducer and N2 fixation metabolic functions in seagrass sediments. Overall, this study showed that seagrasses control benthic bacterial community composition and diversity, enhance heterotrophic carbon substrate utilization, and play crucial roles in organic matter cycling including degradation of hydrocarbon and xenobiotics in coastal sediments.