Bacterial community has been significantly enrolled in the biogeochemical cycling of the coastal subsurface ecosystem. The bacterial community variations with salinity have been extensively investigated in the surface environment, such as lake, soil, and estuary, but not in the subsurface environment. Here we explore the responses of bacterial populations to the salinity and other environmental factors (EFs) by considering both the abundant and rare sub-community in a coastal Holocene groundwater system. Our study results indicate that the bacterial diversity was independent of the salinity in both the abundance and rare sub-community. Besides diversity, no flourishing of abundant bacteria relative abundance is observed with increasing or decreasing salinity. Yet the rare taxa exhibit a bio-growth with salinity, which has a significant correlation (p < 0.001) with sulfate concentration. The responses of the abundant sub-community taxa to nutrients, temperature, pH, and dissolved oxygen are insensitive. However, the correlation between δ¹⁸O, δD and the entire community diversity is significant, which demonstrates the bacterial community is affected by the groundwater origin. Besides, not all the species in one class or order are necessarily shaped by the same factor. To quantify the impact of EFs on the community properties, analyses in different taxonomic levels is suggested. These findings imply that the spatial organization of microbial communities is complicated and influenced by multiple factors on a regional scale. The investigated results are useful for understanding biogeochemical processes in the coastal groundwater.

细菌群落已大量参与沿海地下生态系统的生物地球化学循环。在盐湖，土壤和河口等地表环境中，已经广泛研究了盐度下细菌群落的变化，但在地下环境中却没有进行研究。在这里，我们通过考虑沿海全新世地下水系统中的丰富和稀有的亚群落，探索细菌种群对盐度和其他环境因素（EFs）的响应。我们的研究结果表明，在丰富和稀有的亚群落中，细菌多样性与盐度无关。除了多样性以外，没有观察到盐度增加或减少时丰富细菌相对丰度的增加。但是稀有的分类单元却显示出具有盐分的生物生长，p  <0.001）和硫酸盐浓度。丰富的亚群落分类对营养，温度，pH和溶解氧的反应不敏感。然而，δ之间的相关性¹⁸ O，δD和整个社会的多样性是显著，这表明细菌群落是受地下水的起源。此外，并非一类或一类的所有物种都必须具有相同的形状。为了量化EF对社区特性的影响，建议在不同的分类学级别进行分析。这些发现暗示，微生物群落的空间组织是复杂的，并受区域规模上多个因素的影响。研究结果有助于了解沿海地下水的生物地球化学过程。