Distinct microbial communities alter litter decomposition rates in a fertilized coastal plain wetland
Distinct microbial communities alter litter decomposition rates in a fertilized coastal plain wetland
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DOI：
10.1002/ecs2.3619
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发表时间：
2021-06
期刊：
影响因子：
2.7
通讯作者：
Megan E. Koceja;Regina B. Bledsoe;C. Goodwillie;A. Peralta
中科院分区：
文献类型：
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作者：
Megan E. Koceja;Regina B. Bledsoe;C. Goodwillie;A. Peralta
人类活动导致土壤中氮、磷的沉积增加。众所周知，土壤养分富集可增加植物生物量和微生物凋落物分解率。然而，水文位置和相关的土壤水分变化的相互作用的影响，可以限制微生物的活动，并导致意想不到的微生物群落结构-功能关系的营养反馈。研究营养物富集对分解速率的反馈对于预测微生物对碳（C）循环的贡献是至关重要的，因为营养物的大气沉积持续存在。本研究探讨了长期养分添加和凋落物化学性质对比对土壤细菌群落结构和功能的影响。我们推测，长期的低肥力土壤养分富集改变细菌群落结构，并导致更高的凋落物分解率与降低C：N比的凋落物，但低养分和干燥的条件限制限制微生物分解的高C：N比凋落物。我们利用一个长期的施肥实验，以测试如何养分富集和水文操纵（由于沟渠）影响分解和土壤细菌群落结构在养分贫乏的沿海平原湿地。我们进行了一个垃圾袋实验，并采用16 S rRNA细菌测序和定量凋落物质量损失和土壤理化性质的特点凋落物相关和散装土壤微生物组。结果表明，不同的细菌群落参与了高C：N比凋落物的分解，尤其是在干燥土壤条件下，施肥处理比未施肥处理更快，而绿色茶叶凋落物（低C：N比）的分解速率在施肥和未施肥处理之间相似。细菌群落结构部分解释了凋落物分解速率，长期施肥和干燥的水文状况影响细菌多样性和增加分解速率。然而，社区组成与高C：N凋落物是相似的，在潮湿的地块与可用的硝酸盐检测，无论施肥处理。这项研究提供了深入了解长期施肥对土壤细菌多样性和组成的影响，分解，以及增加土壤碳损失的潜力，因为养分富集和水文相互作用，影响历史上低养分生态系统。
Abstract Human activities have led to increased deposition of nitrogen (N) and phosphorus (P) into soils. Nutrient enrichment of soils is known to increase plant biomass and rates of microbial litter decomposition. However, interacting effects of hydrologic position and associated changes to soil moisture can constrain microbial activity and lead to unexpected nutrient feedbacks on microbial community structure-function relationships. Examining how feedbacks of nutrient enrichment on decomposition rates is essential for predicting microbial contributions to carbon (C) cycling as atmospheric deposition of nutrients persists. This study explores how long-term nutrient addition and contrasting litter chemical quality influence soil bacterial community structure and function. We hypothesize that long-term nutrient enrichment of low fertility soils alters bacterial community structure and leads to higher rates of litter decomposition with decreasing C:N ratio of litter; but low nutrient and dry conditions limit constrain microbial decomposition of high C:N ratio litter. We leverage a long-term fertilization experiment to test how nutrient enrichment and hydrologic manipulation (due to ditches) affects decomposition and soil bacterial community structure in a nutrient poor coastal plain wetland. We conducted a litter bag experiment and characterized litter-associated and bulk soil microbiomes using 16S rRNA bacterial sequencing and quantified litter mass losses and soil physicochemical properties. Results revealed that distinct bacterial communities were involved in decomposing higher C:N ratio litter more quickly in fertilized compared to unfertilized especially under drier soil conditions, while decomposition rates of green tea litter (lower C:N ratio) were similar between fertilized and unfertilized plots. Bacterial community structure in part explained litter decomposition rates, and long-term fertilization and drier hydrologic status affected bacterial diversity and increased decomposition rates. However, community composition associated with high C:N litter was similar in wetter plots with available nitrate detected, regardless of fertilization treatment. This study provides insight into long-term fertilization effects on soil bacterial diversity and composition, decomposition, and the increased potential for soil C loss as nutrient enrichment and hydrology interact to affect historically low nutrient ecosystems.