Data on investigation of Carbon Dynamics Regulated by Microorganisms in Mangrove Wetlands of Hainan, China

This study conducted an experiment on exogenous nitrogen input carried by tidal action in coastal wetlands from August 1, 2023 to January 27, 2024, aiming to investigate the impact of nitrogen input in coastal wetlands on soil carbon dynamics and the microbial mechanisms underlying the changes in carbon dynamics. The experiment lasted for 180 days. Before the experiment, in-situ soil samples and microbial samples were collected to determine the baseline values of soil properties and soil microorganisms (Pre). Meanwhile, the plant height and diameter were measured before the experiment. The soil testing indicators included TN (Total Nitrogen), TC (Total Carbon), TOC (Total Organic Carbon), DOC (Dissolved Organic Carbon), NH₄⁺-N (Ammonium Nitrogen), NO₃-N (Ammonia Nitrogen), pH, and moisture content. After the experiment started, soil samples were collected and tested every 15 days, and the concentrations of CO₂ and CH₄ gases were measured. The ambient temperature during gas measurement was recorded, and the fluxes of CO₂ and CH₄ were obtained through calculation. At the end of the experiment (180 days), data such as plant height and stem diameter were measured again. Meanwhile, microbial samples were collected, and 16S DNA data and functional gene data were obtained through testing. These data were used to monitor changes in soil properties, variations in CO₂ and CH₄ fluxes, and changes in microbial community structure under the condition of exogenous nitrogen input, so as to study the influencing factors of CO₂ and CH₄ emissions, the influencing factors of DOC concentration changes, and the microbial mechanisms of carbon dynamic changes under nitrogen input conditions. The results showed that the release of carbon into the environment in this study mainly came from soil CO₂ emissions and DOC loss. The simulated tidal action caused a large amount of DOC loss, which was the main factor for DOC loss in mangrove wetland soils. The threshold value of nitrogen addition for the transformation effects on soil nutrients (TN, NO₃⁻-N), soil carbon storage (TC, TOC) and plant biomass in mangrove wetlands was 2 (mg/L). Salinity, NH₄⁺-N, and changes in DOC are the key soil components that drive variations in the abundance of microbial functional genes. Nitrogen input increased the abundances of carbon-degrading genes such as amyA, pgu, glx, chiA, and apu, promoted the carbon degradation process, and the production of more substrates led to an increase in CO₂ emissions.本研究于2023年8月1日至2024年1月27日，针对滨海湿地受潮汐作用携带的外源氮输入开展实验，实验周期共计180天，旨在探究滨海湿地氮输入对土壤碳动态的影响，以及碳动态变化背后的微生物驱动机制。 实验开展前，采集原位土壤样品与微生物样品以测定土壤属性及土壤微生物的基线水平（记为Pre组），同时测定植物株高与茎径。本次土壤检测指标包括总氮（Total Nitrogen, TN）、总碳（Total Carbon, TC）、总有机碳（Total Organic Carbon, TOC）、溶解性有机碳（Dissolved Organic Carbon, DOC）、铵态氮（Ammonium Nitrogen, NH₄⁺-N）、硝态氮（Nitrate Nitrogen, NO₃⁻-N）、pH值与土壤含水率。 实验启动后，每15天采集土壤样品进行检测，并测定CO₂与CH₄气体浓度。记录气体测定时的环境温度，通过计算得到CO₂与CH₄的排放通量。 实验结束时（第180天），再次测定植物株高与茎径，同时采集微生物样品，通过测序获得16S DNA数据与功能基因数据。 本数据集用于监测外源氮输入条件下土壤属性的变化、CO₂与CH₄排放通量的变异，以及微生物群落结构的演替，以此探究氮输入条件下CO₂与CH₄排放的影响因素、DOC浓度变化的驱动因子，以及碳动态变化的微生物机制。 研究结果显示，本研究中碳向环境的释放主要来源于土壤CO₂排放与DOC流失。模拟潮汐作用引发了大量溶解性有机碳流失，这是红树林湿地土壤DOC流失的主导因素。红树林湿地中，对土壤养分（总氮、硝态氮）、土壤碳储量（总碳、总有机碳）及植物生物量产生调控转化作用的氮添加阈值为2 mg/L。盐度、铵态氮与DOC的变化是驱动微生物功能基因丰度变异的关键土壤因子。氮输入提升了amyA、pgu、glx、chiA及apu等碳降解基因的丰度，加速了碳降解过程，而更多底物的生成进一步推动了CO₂排放的增加。