Investigation of Antarctic Marine Metazoan Biodiversity Through Metagenomic Analysis of Environmental DNA

Environmental DNA (eDNA), or DNA extracted from environmental collections, is frequently used to gauge biodiversity and identify the presence of rare or invasive species within a habitat. Previous studies have demonstrated that compared to traditional surveying methods, high-throughput sequencing of eDNA can provide increased detection sensitivity of aquatic taxa, holding promise for various conservation applications. To determine the potential of eDNA for assessing biodiversity of Antarctic marine metazoan communities, we have extracted eDNA from seawater sampled from four regions near Palmer Station in West Antarctic Peninsula. Metagenomic sequencing of the eDNA was performed on Illumina HiSeq2500, and produced 325 million quality-processed reads. Preliminary read mapping for two regions, Gerlache Strait and Bismarck Strait, identified approximately 4% of reads mapping to eukaryotes for each region, with >50% of the those reads mapping to metazoan animals. Key groups investigated include the nototheniidae family of Antarctic fishes, to which 0.2 and 0.8 % of the metazoan reads were assigned for each region respectively. The presence of the recently invading lithodidae king crabs was also detected at both regions. Additionally, to estimate the persistence of eDNA in polar seawater, a rate of eDNA decay will be quantified from seawater samples collected over 20 days from Antarctic fish holding tanks and held at ambient Antarctic water temperatures. The ability to detect animal signatures from eDNA, as well as the quantification of eDNA decay over time, could provide another method for reliable monitoring of polar habitats at various spatial and temporal scales.