Data from: Spatio-temporal monitoring of deep-sea communities using metabarcoding of sediment DNA and RNA

We assessed spatio-temporal patterns of diversity in deep-sea sediment communities using metabarcoding. We chose a recently developed eukaryotic marker based on the v7 region of the 18S rRNA gene. Our study was performed in a submarine canyon and its adjacent slope in the Northwestern Mediterranean Sea, sampled along a depth gradient at two different seasons. We found a total of 5,569 molecular operational taxonomic units (MOTUs), dominated by Metazoa, Alveolata and Rhizaria. Among metazoans, Nematoda, Arthropoda and Annelida were the most diverse. We found a marked heterogeneity at all scales, with important differences between layers of sediment and significant changes in community composition with zone (canyon vs slope), depth, and season. We compared the information obtained from metabarcoding DNA and RNA and found more total MOTUs and more MOTUs per sample with DNA (ca. 20% and 40% increase, respectively). Both datasets showed overall similar spatial trends, but most groups had higher MOTU richness with the DNA template, while others, such as nematodes, were more diverse in the RNA dataset. We provide metabarcoding protocols and guidelines for biomonitoring of these key communities in order to generate information applicable to management efforts.

本研究采用元条形码（metabarcoding）技术，解析了深海沉积物群落多样性的时空分布格局。本研究选用了基于18S核糖体RNA（18S rRNA）基因v7区开发的新型真核生物标记序列。研究区域设于地中海西北部的一处海底峡谷及其毗邻陆坡，沿深度梯度设置采样点，并在两个不同季节完成了采样工作。本研究共获得5569个分子操作分类单元（molecular operational taxonomic units, MOTUs），优势类群为后生动物（Metazoa）、囊泡虫类（Alveolata）与丝足虫类（Rhizaria）。在后生动物类群中，线虫动物门（Nematoda）、节肢动物门（Arthropoda）和环节动物门（Annelida）的物种多样性最为丰富。本研究发现各尺度下均存在显著的群落异质性：沉积物不同层位间存在明显差异，且群落组成随区域（峡谷与陆坡）、水深和季节发生显著变化。本研究对比了基于DNA和RNA的元条形码测序结果，发现以DNA为模板时获得的总MOTUs数量及单样本MOTUs数量均更高，分别提升约20%和40%。两类测序数据集整体呈现相似的空间分布趋势，但多数类群在DNA模板下的MOTU丰富度更高，而部分类群（如线虫类）则在RNA数据集下表现出更高的多样性。本研究同时提供了针对这类关键群落的生物监测元条形码实验方案与指导规范，以期为相关海洋管理工作提供可借鉴的科学依据。