title: Nutrient input influences fungal community composition and size and can stimulate manganese (II) oxidation in caves.
abstract: 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.
authors: Department of Geology, Appalachian State University, Boone, NC, 28608, USA.
authors: Sarah K
authors: SK
authors: Carmichael
authors: Department of Biology, Appalachian State University, Boone, NC, 28608, USA.
authors: Bryan T
authors: BT
authors: Zorn
authors: Smithsonian Institution, National Museum of Natural History, Washington, DC, 20560, USA.
authors: Cara M
authors: CM
authors: Santelli
authors: Department of Geology, University of Maryland, College Park, MD, 20742, USA.
authors: Leigh A
authors: LA
authors: Roble
authors: Department of Biology, Wake Forest University, Winston-Salem, NC, 27109, USA.
authors: Mary J
authors: MJ
authors: Carmichael
authors: Department of Biology, Appalachian State University, Boone, NC, 28608, USA.
authors: Suzanna L
authors: SL
authors: Bräuer
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000378:metabolism; D058491:Bacterial Load; D001487:Basidiomycota; D058448:Biota / Q000187:drug effects*; D002244:Carbon / Q000378:metabolism*; D059552:Caves; D015169:Colony Count, Microbial; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005502:Food; D005658:Fungi / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008345:Manganese / Q000378:metabolism*; D008969:Molecular Sequence Data; D025282:Mycelium / Q000254:growth & development; D010084:Oxidation-Reduction; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D008345:Manganese; D002244:Carbon