OBJ1, the aim is to describe the diversity of phytoplankton and their export into sediments and for this purpose samples were collected along the north Greenland coast (west and east), Nares strait, Baffin Bay and from the Lincoln Sea. Environmental DNA samples were extracted from sea ice, surface water, the chlorophyll a max, disphotic zone and surface sediments (seabed), and amplicon sequencing of the small subunit 18S rRNA V4 region, was applied. Main achievement the taxonomic biodiversity reference database is established for three data sets. Field work was conducted in summer 2021 to obtain the fourth data set, DNA has been extracted and plans are made for downstream applications.
OBJ2, the aim is to identify species suitable to be sea ice tracers. Based on material available and the results from OBJ1 the target species have been selected: Target 1. Polarella glacialis, a dinoflagellate with circum-polar distribution. The results from this study combine data collected during several large international projects and research expeditions in the Arctic region spanning over a decade, and gathered a team of scientists from Denmark, Greenland, Canada, and Norway. The modern distribution of P. glacialis was examined in sea ice cores samples, ice-loaded waters and material collected using sediment traps from various locations in the Arctic. Validation of this novel proxy was done by quantifying P. glacialis DNA in surface sediment samples from Arctic marine and fjord settings using a quantitative droplet digital PCR (ddPCR) assay and sediment records spanning the Holocene epoch. The results were compared with sea ice concentration data derived from remote sensing and in situ observations, and to the widely used sea ice proxy IP25. Target 2. Six strains of sea ice diatoms were available through collaboration at ULaval. The diatoms are isolated from sea ice in Hudson Strait and include the sea ice biomarker Haslea spicula (3 strains), H. kjellmannii (1 strain), Gyrosigma tenuissimum var. hyperborea. (1 strain), Navicula sp. (1 strain). Additionally, isolated DNA from other biomarker producing Haslea species (H. crucerigoides and H. vitrea) isolated from Svalbard are included in this study.
The results achieved so far, for target 1 we have suggested a new sea ice proxy P. glacialis DNA (Pgla-DNA) and the paper is in review. Pgla-DNA is the first quantitative DNA-based proxy, stemming from a sound ecological knowledge of recorded association to the sea ice. We are confident this new proxy has the potential to improve the representation of sea ice variability in climate and ecosystem models. For target 2 the Sequencing was performed on six cultures and reference building targeted the ribosomal small subunit nuclear 18S rRNA hypervariable gene regions V4, V7, V9, Internal Transcribed Spacer regions, ITS 1 and ITS 2, and the chloroplast gene rbcL.
