Mootapally Chandrashekar, Sharma Parth, Dash Siddhant, Kumar Manish, Sharma Shiksha, Kothari Ramesh, Nathani Neelam
School of Applied Sciences and Technology, Gujarat Technological University, Ahmedabad 382424, Gujarat, India.
School of Applied Sciences and Technology, Gujarat Technological University, Ahmedabad 382424, Gujarat, India; Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
Sci Total Environ. 2025 Feb 15;965:178609. doi: 10.1016/j.scitotenv.2025.178609. Epub 2025 Jan 31.
Deep marine sediments are rich in microbial diversity, which holds metabolic repertoire to modulate biogeochemical cycles on a global scale. We undertook the environmental microbiome inhabiting the Gulf of Kathiawar Peninsula as a model system to understand the potential involvement of the deep marine sediment microbial community and as a cohort in the carbon, nitrogen, and sulfur biogeochemical cycles. These gulfs are characterized by dynamic tidal variations, diverse sediment textures, and nutrient-rich waters, driven by coastal processes and the interaction between natural coastal dynamics and anthropogenic inputs that shape its microbial community diversity. Our findings suggest that carbon fixation was carried out by Gamma-proteobacteria with CBB cycle-related genes or by microbial participants with Wood-Ljungdahl pathway-related genes. Microbial communities involved in nitrogen metabolism were observed to be rich and diverse, and most microbial communities potentially contribute to the nitrogen cycle via processing nitrogen oxides. Bacteria belonging to the KSB1 phylum were also found to fix nitrogen. The sulfur cycle was spread throughout, with Verrucomicrobiota phylum being a major contributor. The varying napAB genes, significantly lower in the Gulf of Kutch compared to the Gulf of Cambay and the Arabian Sea, mediated nitrate reduction. Dynamics between these pathways were mutually exclusive, and organic carbon oxidation was widespread across the microbial community. Finally, the proteobacteria phylum was highly versatile and conceivably contributed to biogeochemical flux with exceptionally high abundance and the ability to form metabolic networks to survive. The work highlights the importance of critical zones and microbial diversity therein, which needs further exploration.
深海沉积物富含微生物多样性，拥有在全球范围内调节生物地球化学循环的代谢库。我们以卡提阿瓦半岛海湾的环境微生物群落为模型系统，来了解深海沉积物微生物群落的潜在作用以及其在碳、氮和硫生物地球化学循环中的作用。这些海湾的特点是潮汐变化动态、沉积物质地多样且水体营养丰富，受海岸过程以及塑造其微生物群落多样性的自然海岸动态与人为输入之间的相互作用驱动。我们的研究结果表明，碳固定是由具有卡尔文循环相关基因的γ-变形菌或具有伍德-Ljungdahl途径相关基因的微生物参与者进行的。观察到参与氮代谢的微生物群落丰富多样，并且大多数微生物群落可能通过处理氮氧化物对氮循环做出贡献。还发现属于KSB1门的细菌能够固氮。硫循环广泛存在，疣微菌门是主要贡献者。与坎贝湾和阿拉伯海相比，卡奇湾中不同的napAB基因显著降低，介导了硝酸盐还原。这些途径之间的动态相互排斥，有机碳氧化在微生物群落中广泛存在。最后，变形菌门具有高度的多功能性，可能以极高的丰度和形成代谢网络以生存的能力对生物地球化学通量做出贡献。这项工作突出了关键区域及其内微生物多样性的重要性，这需要进一步探索。
