Clarke Laurence J, Suter Leonie, Deagle Bruce E, Polanowski Andrea M, Terauds Aleks, Johnstone Glenn J, Stark Jonathan S
Australian Antarctic Division, Kingston, Tasmania, Australia.
Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia.
PeerJ. 2021 Nov 15;9:e12458. doi: 10.7717/peerj.12458. eCollection 2021.
Antarctic benthic ecosystems support high biodiversity but their characterization is limited to a few well-studied areas, due to the extreme environment and remoteness making access and sampling difficult. Our aim was to compare water and sediment as sources of environmental DNA (eDNA) to better characterise Antarctic benthic communities and further develop practical approaches for DNA-based biodiversity assessment in remote environments. We used a cytochrome oxidase subunit I (COI) metabarcoding approach to characterise metazoan communities in 26 nearshore sites across 12 locations in the Vestfold Hills (East Antarctica) based on DNA extracted from either sediment cores or filtered seawater. We detected a total of 99 metazoan species from 12 phyla across 26 sites, with similar numbers of species detected in sediment and water eDNA samples. However, significantly different communities were detected in the two sample types at sites where both were collected (, where paired samples were available). For example, nematodes and echinoderms were more likely to be detected exclusively in sediment and water eDNA samples, respectively. eDNA from water and sediment core samples are complementary sample types, with epifauna more likely to be detected in water column samples and infauna in sediment. More reference DNA sequences are needed for infauna/meiofauna to increase the proportion of sequences and number of taxa that can be identified. Developing a better understanding of the temporal and spatial dynamics of eDNA at low temperatures would also aid interpretation of eDNA signals from polar environments. Our results provide a preliminary scan of benthic metazoan communities in the Vestfold Hills, with additional markers required to provide a comprehensive biodiversity survey. However, our study demonstrates the choice of sample type for eDNA studies of benthic ecosystems (sediment, water or both) needs to be carefully considered in light of the research or monitoring question of interest.
南极底栖生态系统拥有高度的生物多样性，但由于极端环境和地处偏远，使得进入和采样困难，其特征描述仅限于少数几个经过充分研究的区域。我们的目标是比较水和沉积物作为环境DNA（eDNA）来源，以更好地描述南极底栖生物群落，并进一步开发在偏远环境中基于DNA的生物多样性评估实用方法。我们采用细胞色素氧化酶亚基I（COI）宏条形码方法，基于从沉积物岩芯或过滤海水中提取的DNA，对南极东部维斯福特山12个地点的26个近岸站点的后生动物群落进行特征描述。我们在26个站点共检测到来自12个门的99种后生动物，沉积物和水样中的eDNA样本检测到的物种数量相似。然而，在同时采集两种样本的站点，两种样本类型检测到的群落存在显著差异（，这里指有配对样本的情况）。例如，线虫和棘皮动物分别更有可能仅在沉积物和水样的eDNA样本中被检测到。来自水和沉积物岩芯样本的eDNA是互补的样本类型，表栖动物更有可能在水柱样本中被检测到，而底内动物则在沉积物中。需要更多的底内动物/小型底栖动物参考DNA序列，以提高可识别的序列比例和分类单元数量。更好地了解低温下eDNA的时空动态也将有助于解释来自极地环境的eDNA信号。我们的结果对维斯福特山的底栖后生动物群落进行了初步扫描，还需要额外的标记来进行全面的生物多样性调查。然而，我们的研究表明，根据感兴趣的研究或监测问题，需要仔细考虑用于底栖生态系统eDNA研究的样本类型（沉积物、水或两者）。
