Lake sediment multi-taxon DNA from North Greenland records early post-glacial appearance of vascular plants and accurately tracks environmental changes

Abstract

a b s t r a c tHigh Arctic environments are particularly sensitive to climate changes, but retrieval of paleoecological data is challenging due to low productivity and biomass. At the same time, Arctic soils and sediments have proven exceptional for long-term DNA preservation due to their constantly low temperatures. Lake sediments contain DNA paleorecords of the surrounding ecosystems and can be used to retrieve a variety of organismal groups from a single sample. In this study, we analyzed vascular plant, bryophyte, algal (in particular diatom) and copepod DNA retrieved from a sediment core spanning the Holocene, taken from Bliss Lake on the northernmost coast of Greenland. A previous multi-proxy study including microscopic diatom analyses showed that this lake experienced changes between marine and lacustrine conditions. We inferred the same environmental changes from algal DNA preserved in the sediment core. Our DNA record was stratigraphically coherent, with no indication of leaching between layers, and our cross-taxon comparisons were in accordance with previously inferred local ecosystem changes. Authentic ancient plant DNA was retrieved from nearly all layers, both from the marine and the limnic phases, and distinct temporal changes in plant presence were recovered. The plant DNA was mostly in agreement with expected vegetation history, but very early occurrences of vascular plants, including the woody Empetrum nigrum, document terrestrial vegetation very shortly after glacial retreat. Our study shows that multitaxon metabarcoding of sedimentary ancient DNA from lake cores is a valuable tool both for terrestrial and aquatic paleoecology, even in low-productivity ecosystems such as the High Arctic.

How have studies of ancient DNA from sediments contributed to the reconstruction of Quaternary floras?

“…Sequences from ‘food or cultivated plants’ and taxa ‘highly unlikely to have been present’ were excluded by Epp et al . ().…”

“…Picea DNA was recorded and interpreted as contamination by pollen carried into the DNA extraction laboratory. Epp et al (2015) found aDNA of 17 vascular plants and eight bryophyte taxa from Holocene sediments from a high Arctic lake in northern Greenland. The determinations were mainly at a generic or family level with five species identifications.…”

Untitled

“…Qubit ® Fluorometer is widely used for DNA quantification in many previous studies due to its accuracy and sensitivity. [9][10][11][12][13] Total DNA yields from DNA standards using 2 different DNA extraction methods in forensic DNA analysis, QIAmp DNA kit is widely employed for DNA extraction since it allows for quick and easy extraction. However, we hypothesized that the kit may yield low amounts of DNA due to the fact that DNA is usually lost during the DNA-membrane binding process, washing and DNA elution.…”

The efficacy of high-throughput sequencing and target enrichment on charred archaeobotanical remains

“…Despite the most stringent efforts, however, contamination can still occur and may be more likely when working with ubiquitous commercial crops, such as members of the Triticeae 4748. This is particularly problematic given many charred archaeobotanical studies aim to investigate aspects of historical domestication and the spread of agriculture in these species26.…”