Kiel Reese Brandi, Sobol Morgan S, Bowles Marshall Wayne, Hinrichs Kai-Uwe
Dauphin Island Sea Lab, Dauphin Island, AL, United States.
School of Marine and Environmental Sciences, University of South Alabama, Mobile, AL, United States.
Front Fungal Biol. 2021 Sep 24;2:727543. doi: 10.3389/ffunb.2021.727543. eCollection 2021.
The characterization of metabolically active fungal isolates within the deep marine subsurface will alter current ecosystem models and living biomass estimates that are limited to bacterial and archaeal populations. Although marine fungi have been studied for over fifty years, a detailed description of fungal populations within the deep subsurface is lacking. Fungi possess metabolic pathways capable of utilizing previously considered non-bioavailable energy reserves. Therefore, metabolically active fungi would occupy a unique niche within subsurface ecosystems, with the potential to provide an organic carbon source for heterotrophic prokaryotic populations from the transformation of non-bioavailable energy into substrates, as well as from the fungal necromass itself. These organic carbon sources are not currently being considered in subsurface energy budgets. Sediments from South Pacific Gyre subsurface, one of the most energy-limited environments on Earth, were collected during the Integrated Ocean Drilling Program Expedition 329. Anoxic and oxic sediment slurry enrichments using fresh sediment were used to isolate multiple fungal strains in media types that varied in organic carbon substrates and concentration. Metabolically active and dormant fungal populations were also determined from nucleic acids extracted from cryopreserved South Pacific Gyre sediments. For further characterization of physical growth parameters, two isolates were chosen based on their representation of the whole South Pacific Gyre fungal community. Results from this study show that fungi have adapted to be metabolically active and key community members in South Pacific Gyre sediments and potentially within global biogeochemical cycles.
对深海次表层具有代谢活性的真菌分离株的特性描述，将改变目前仅限于细菌和古菌种群的生态系统模型和生物量估计。尽管对海洋真菌的研究已有五十多年，但仍缺乏对深海次表层真菌种群的详细描述。真菌拥有能够利用以前被认为不可生物利用的能量储备的代谢途径。因此，具有代谢活性的真菌将在次表层生态系统中占据独特的生态位，有可能通过将不可生物利用的能量转化为底物，以及通过真菌自身的坏死物质，为异养原核生物种群提供有机碳源。目前在次表层能量预算中尚未考虑这些有机碳源。在综合大洋钻探计划第329航次期间收集了来自南太平洋环流次表层的沉积物，南太平洋环流是地球上能量最有限的环境之一。使用新鲜沉积物进行缺氧和有氧沉积物浆液富集，以在有机碳底物和浓度不同的培养基类型中分离多种真菌菌株。还从冷冻保存的南太平洋环流沉积物中提取的核酸中确定了具有代谢活性和休眠的真菌种群。为了进一步表征物理生长参数，根据它们对整个南太平洋环流真菌群落的代表性选择了两个分离株。这项研究的结果表明，真菌已经适应在南太平洋环流沉积物中以及潜在地在全球生物地球化学循环中具有代谢活性并成为关键的群落成员。
