Key Laboratory of the Ministry of Education for Coastal Wetland Ecosystems, Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, College of the Environment and Ecology, Xiamen University, Xiang'an South Road, Xiamen 361102, China.
China ASEAN College of Marine Sciences, Xiamen University Malaysia, Jalan Sunsuria Bandar Sunsuria, Sepang 43900, Malaysia.
Sci Total Environ. 2024 Jun 10;928:172575. doi: 10.1016/j.scitotenv.2024.172575. Epub 2024 Apr 17.
Phosphorus (P) plays an important role in regulating primary production in estuarine environments. However, knowledge of the P-functional gene composition of microbial communities and the mechanisms of microbial adaptation to changes in available P in estuaries remain limited. This study coupling 16 s rDNA and metagenomics sequencing was conducted to reveal the relationship between P cycling functional genes, microbial interactions, and P availability in the Jiulong River Estuary. The results showed that the relative abundance of P cycling functions genes was highest in winter, and lowest in summer. Spatially, the total relative abundance of P cycling functions genes was higher in the riverward than that in the seaward. P cycling functional microbial interactions and P cycling gene coupling were strongest in summer and in the seaward. Changes in both temperature and salinity had significant direct and indirect effects on P cycling function, and the influence of salinity on P cycling function was greater than that on the microbial community in the estuary. Salinity had significant direct negative effects on inorganic P-solubilization (IP), organic P-mineralization (OP), and P uptake and transport functions (PT). Whereas, salinity had a significant positive effect on P-starvation response regulation (PR) function. Thus, salinity and microbial communities regulate the soluble reactive phosphate concentrations in estuarine environments by strengthening internal coupling among P cycling functions, promoting PR function, and facilitating PT gene expression. PR is the most important predictors, PR, PT, and PR-PT together explained 38.56 % of the overall soluble reactive phosphorus (SRP) variation. Over 66 % of the explained SRP variations can be predicted by the PR, PT, and PR-PT functional genes. This finding improves the knowledge base of the microbial processes for P cycling and provides a foundation for eutrophication management strategies in the estuary.
磷（P）在调节河口环境中的初级生产力方面起着重要作用。然而，关于微生物群落中 P 功能基因组成以及微生物适应河口可利用磷变化的机制的知识仍然有限。本研究结合 16s rDNA 和宏基因组测序，揭示了九龙江河口磷循环功能基因、微生物相互作用与磷可利用性之间的关系。结果表明，磷循环功能基因的相对丰度冬季最高，夏季最低。空间上，河流向的磷循环功能基因总相对丰度高于海洋向。夏季和海洋向的磷循环功能微生物相互作用和磷循环基因偶联最强。温度和盐度的变化对磷循环功能有显著的直接和间接影响，盐度对磷循环功能的影响大于对河口微生物群落的影响。盐度对无机磷溶解（IP）、有机磷矿化（OP）和磷吸收与转运功能（PT）有显著的直接负效应。然而，盐度对 P 饥饿响应调节（PR）功能有显著的正效应。因此，盐度和微生物群落通过加强磷循环功能的内部偶联、促进 PR 功能和促进 PT 基因表达来调节河口环境中的可溶反应性磷酸盐浓度。PR 是最重要的预测因子，PR、PT 和 PR-PT 共同解释了 38.56%的总可溶反应性磷（SRP）变化。PR、PT 和 PR-PT 功能基因可以预测超过 66%的解释 SRP 变化。这一发现提高了微生物磷循环过程的知识基础，并为河口富营养化管理策略提供了基础。
