Nutrient input influences fungal community composition and size and can stimulate manganese (II) oxidation in caves
Nutrient input influences fungal community composition and size and can stimulate manganese (II) oxidation in caves
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DOI：
10.1111/1758-2229.12291
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发表时间：
2015-08-01
影响因子：
3.3
通讯作者：
Braeuer, Suzanna L.
中科院分区：
文献类型：
--
作者：
Carmichael, Sarah K.;Zorn, Bryan T.;Braeuer, Suzanna L.
真菌在低营养生态系统生物地球化学循环中的作用尚不清楚。本研究比较了阿巴拉契亚南部两个洞穴的真菌群落，并评估了外源碳对微生物群落结构和功能的影响：一个人为影响的洞穴和一个接近原始的洞穴。由于受到浅层土壤碳输入的影响，受人为影响的洞穴真菌和细菌qPCR基因拷贝数显著增加，群落多样性显著增加，并以早期常见的囊孢菌类群为主，易挥发有机质分解。在接近原始的洞穴样本中，真菌组合主要是担子菌，通常在较深的土壤中发现（和/或在后期，顽固的有机物分解），表明更多的少营养条件。原位添加碳和锰（II） [Mn(II)]超过10周导致真菌菌丝生长，随后Mn（II）氧化增加。真菌群落的前后比较表明，这种富集增加了真菌和细菌细胞的数量，但降低了真菌的总体多样性。因此，人为碳源可以显著影响真菌的多样性和数量，影响微生物群落功能，并刺激Mn（II）氧化，导致一系列变化，这些变化可以强烈影响喀斯特含水层的营养和微量元素生物地球化学循环。
Little is known about the fungal role in biogeochemical cycling in oligotrophic ecosystems. This study compared fungal communities and assessed the role of exogenous carbon on microbial community structure and function in two southern Appalachian caves: an anthropogenically impacted cave and a near-pristine cave. Due to carbon input from shallow soils, the anthropogenically impacted cave had an order of magnitude greater fungal and bacterial quantitative-polymerase chain reaction (qPCR) gene copy numbers, had significantly greater community diversity, and was dominated by ascomycotal phylotypes common in early phase, labile organic matter decomposition. Fungal assemblages in the near-pristine cave samples were dominated by Basidiomycota typically found in deeper soils (and/or in late phase, recalcitrant organic matter decomposition), suggesting more oligotrophic conditions. In situ carbon and manganese (II) [Mn(II)] addition over 10 weeks resulted in growth of fungal mycelia followed by increased Mn(II) oxidation. A before/after comparison of the fungal communities indicated that this enrichment increased the quantity of fungal and bacterial cells, yet decreased overall fungal diversity. Anthropogenic carbon sources can therefore dramatically influence the diversity and quantity of fungi, impact microbial community function, and stimulate Mn(II) oxidation, resulting in a cascade of changes that can strongly influence nutrient and trace element biogeochemical cycles in karst aquifers.