PDF(Pubmed)
Abstract：
Testate amoebae (order Arcellinida) are abundant in freshwater ecosystems, including low pH bogs and fens. Within these environments, Arcellinida are considered top predators in microbial food webs and their tests are useful bioindicators of paleoclimatic changes and anthropogenic pollutants. Accurate species identifications and characterizations of diversity are important for studies of paleoclimate, microbial ecology, and environmental change; however, morphological species definitions mask cryptic diversity, which is a common phenomenon among microbial eukaryotes. Lineage-specific primers recently designed to target Arcellinida for amplicon sequencing successfully captured a poorly-described yet diverse fraction of the microbial eukaryotic community. Here, we leveraged the application of these newly-designed primers to survey the diversity of Arcellinida in four low-pH New England bogs and fens, investigating variation among bogs (2018) and then across seasons and habitats within two bogs (2019). Three OTUs represented 66% of Arcellinida reads obtained across all habitats surveyed. 103 additional OTUs were present in lower abundance with some OTUs detected in only one sampling location, suggesting habitat specificity. By establishing a baseline for Arcellinida diversity, we provide a foundation to monitor key taxa in habitats that are predicted to change with increasing anthropogenic pressure and rapid climate change.
摘要：
在淡水生态系统中，变形虫（Arcellinida目）丰富，包括低pH值沼泽和芬斯。在这些环境中,Arcellinida被认为是微生物食物网中的顶级捕食者，其测试是古气候变化和人为污染物的有用生物指标。准确的物种识别和多样性表征对于古气候研究非常重要，微生物生态学,和环境变化；然而，形态物种定义掩盖了神秘的多样性，这是微生物真核生物中的普遍现象。最近设计用于扩增子测序的针对Arcellinida的谱系特异性引物成功捕获了微生物真核生物群落中描述不佳但多样的部分。这里,我们利用这些新设计的引物来调查四个低pH新英格兰沼泽和芬斯中Arcellinida的多样性，调查沼泽之间的变化(2018年)，然后调查两个沼泽中的季节和栖息地之间的变化(2019年)。三个OTU代表了在所调查的所有栖息地中获得的Arcellinida读数的66％。103个额外的OTU以较低的丰度存在，仅在一个采样位置检测到一些OTU，表明栖息地的特殊性。通过建立Arcellinida多样性的基线，我们为监测栖息地中的关键分类群提供了基础，这些分类群预计会随着人为压力的增加和快速的气候变化而变化。
