Year-around survey and manipulation experiments reveal differential sensitivities of soil prokaryotic and fungal communities to saltwater intrusion in Florida Everglades wetlands
Year-around survey and manipulation experiments reveal differential sensitivities of soil prokaryotic and fungal communities to saltwater intrusion in Florida Everglades wetlands
复制标题
全年调查和操作实验揭示了佛罗里达大沼泽地湿地土壤原核和真菌群落对盐水入侵的不同敏感性
DOI：
10.1016/j.scitotenv.2022.159865
复制
发表时间：
2023
影响因子：
9.8
通讯作者：
Gaiser, Evelyn
中科院分区：
文献类型：
--
作者：
Zhao, Jun;Chakrabarti, Seemanti;Chambers, Randolph;Weisenhorn, Pamela;Travieso, Rafael;Stumpf, Sandro;Standen, Emily;Briceno, Henry;Troxler, Tiffany;Gaiser, Evelyn
全球海平面上升正在改变沿海生态系统，特别是淡水湿地，部分原因是间歇性或长期性盐水暴露增加，导致生物地球化学、植物和微生物群落以及生态服务发生变化。然而，它仍然是难以预测的土壤微生物群落如何响应于盐水暴露，因为知之甚少复杂的湿地土壤微生物群落中的微生物敏感性，以及湿地土壤和盐水暴露的高度时空异质性。为了解决这一问题，我们首先进行了为期两年的调查，微生物群落结构和底层水化学淹没表层土壤从14个湿地地点横跨佛罗里达大沼泽地。我们确定了生态系统特定的微生物生物标志物类群主要与盐度的变化。细菌，古菌和真菌群落组成不同的淡水，红树林，和海洋海草草甸网站，无论土壤类型或季节。特别是，甲烷菌，推定的反硝化甲烷氧化菌和硫酸盐还原菌转移的相对丰度和/或湿地类型之间的组合物。从淡水到海洋湿地，产甲烷菌和假定的反硝化甲烷氧化菌的相对丰度下降，而硫酸盐还原菌则表现出相反的趋势。一个为期四年的实验模拟盐水入侵在一个原始的淡水网站和以前的盐水影响的网站证实了最高的敏感性和硫酸盐还原剂的相对增加，以及分类特异性的敏感性的产甲烷菌，在响应不断脉冲的盐水处理。总的来说，这些结果表明，除了增加的盐度，盐水介导的硫酸盐可用性增加，导致即使在低或暂时的盐暴露的硫酸盐还原剂的甲烷菌的位移。微生物组成的这些变化可能会影响暴露于海平面上升的沿海淡水湿地中的有机物降解途径，并可能造成潜在后果，如土壤有机碳储存的损失。
Global sea-level rise is transforming coastal ecosystems, especially freshwater wetlands, in part due to increased episodic or chronic saltwater exposure, leading to shifts in biogeochemistry, plant- and microbial communities, as well as ecological services. Yet, it is still difficult to predict how soil microbial communities respond to the saltwater exposure because of poorly understood microbial sensitivity within complex wetland soil microbial communities, as well as the high spatial and temporal heterogeneity of wetland soils and saltwater exposure. To address this, we first conducted a two-year survey of microbial community structure and bottom water chemistry in submerged surface soils from 14 wetland sites across the Florida Everglades. We identified ecosystem-specific microbial biomarker taxa primarily associated with variation in salinity. Bacterial, archaeal and fungal community composition differed between freshwater, mangrove, and marine seagrass meadow sites, irrespective of soil type or season. Especially, methanogens, putative denitrifying methanotrophs and sulfate reducers shifted in relative abundance and/or composition between wetland types. Methanogens and putative denitrifying methanotrophs declined in relative abundance from freshwater to marine wetlands, whereas sulfate reducers showed the opposite trend. A four-year experimental simulation of saltwater intrusion in a pristine freshwater site and a previously saltwater-impacted site corroborated the highest sensitivity and relative increase of sulfate reducers, as well as taxon-specific sensitivity of methanogens, in response to continuously pulsing of saltwater treatment. Collectively, these results suggest that besides increased salinity, saltwater-mediated increased sulfate availability leads to displacement of methanogens by sulfate reducers even at low or temporal salt exposure. These changes of microbial composition could affect organic matter degradation pathways in coastal freshwater wetlands exposed to sea-level rise, with potential consequences, such as loss of stored soil organic carbon.