Rojas-Jimenez Keilor, Grossart Hans-Peter, Cordes Erik, Cortés Jorge
Escuela de Biología, Universidad de Costa Rica, San José, Costa Rica.
Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
Front Microbiol. 2020 Nov 6;11:575207. doi: 10.3389/fmicb.2020.575207. eCollection 2020.
Deep waters represent the largest biome on Earth and the largest ecosystem of Costa Rica. Fungi play a fundamental role in global biogeochemical cycling in marine sediments, yet, they remain little explored. We studied fungal diversity and community composition in several marine sediments from 16 locations sampled along a bathymetric gradient (from a depth of 380 to 3,474 m) in two transects of about 1,500 km length in the Eastern Tropical Pacific (ETP) of Costa Rica. Sequence analysis of the V7-V8 region of the 18S rRNA gene obtained from sediment cores revealed the presence of 787 fungal amplicon sequence variants (ASVs). On average, we detected a richness of 75 fungal ASVs per sample. Ascomycota represented the most abundant phylum with Saccharomycetes constituting the dominant class. Three ASVs accounted for ca. 63% of all fungal sequences: the yeast (49.4%), (6.9%), and (6.7%). We distinguished a cluster composed mainly by yeasts, and a second cluster by filamentous fungi, but we were unable to detect a strong effect of depth and the overlying water temperature, salinity, dissolved oxygen (DO), and pH on the composition of fungal communities. We highlight the need to understand further the ecological role of fungi in deep-sea ecosystems.
深海是地球上最大的生物群落，也是哥斯达黎加最大的生态系统。真菌在海洋沉积物的全球生物地球化学循环中发挥着重要作用，然而，它们仍未得到充分研究。我们研究了在哥斯达黎加东部热带太平洋（ETP）两个长度约1500公里的断面中，沿着深度梯度（从380米到3474米）采集的16个地点的几种海洋沉积物中的真菌多样性和群落组成。对从沉积物岩芯中获得的18S rRNA基因V7-V8区域的序列分析显示存在787个真菌扩增子序列变体（ASV）。平均而言，我们每个样本检测到75个真菌ASV。子囊菌门是最丰富的门类，酵母菌纲是优势类群。三个ASV约占所有真菌序列的63%：酵母（49.4%）、（6.9%）和（6.7%）。我们区分出一个主要由酵母组成的簇和一个由丝状真菌组成的第二个簇，但我们未能检测到深度以及上覆水温、盐度、溶解氧（DO）和pH对真菌群落组成的强烈影响。我们强调需要进一步了解真菌在深海生态系统中的生态作用。
