Environmental DNA analyses from the One Ocean Expedition freely available

Insight

Published: 24.02.2023
Oppdatert: 24.02.2023

Thierry Baussant
Ove Daae Lampe
Adriana Krolicka
Jeremy Cook

NORCE have installed equipment for sampling and analysing environmental DNA (eDNA) during the expedition. eDNA can provide a fingerprint of the presence of a large spectra of organisms from bacteria to larger fish and marine mammals collected from simple environmental samples. NORCE will be analysing all the samples when Statsraad Lehmkuhl returns with the samples in April 2023, but some dedicated analyses are also carried out readily on-board and the results sent through the communications systems on a cloud portal accessible by scientists on land for further analytics.

Theme river plot illustrating the relative abundance of species along the expedition transect, obtained from continuous eDNA sampling during the One Ocean Expedition.

Environmental DNA analyses from the One Ocean Expedition freely available

NORCE is participating in the One Ocean Expedition (OOE), collecting scientific data on board the 3 masted barque Statsraad Lehmkuhl. OOE is organized in the frame of the UN Decade of Ocean and with the overall ambition to collect important ocean data to add knowledge about the state of the world's ocean with a special focus on the distribution and diversity of key marine organisms, environmental status, climate, and human pressures on the ocean ecosystems. The observations will provide a broad snapshot on the state of the different oceanic regions, covering world oceanic regions otherwise difficult to access through regular scientific cruises.

A wide range of scientific instruments are deployed for use during the journey. NORCE have installed equipment for sampling and analysing environmental DNA (eDNA) during the expedition. eDNA can provide a fingerprint of the presence of a large spectra of organisms from bacteria to larger fish and marine mammals collected from simple environmental samples. NORCE will be analysing all the samples when Statsraad Lehmkuhl returns with the samples in April 2023, but some dedicated analyses are also carried out readily on-board and the results sent through the communications systems on a cloud portal accessible by scientists on land for further analytics.

To that purpose, 11 selected “target” species have been chosen for on-site detection and measurement to quantify their relative abundance in the world ocean. The relative abundance of each of these key species might give us some clue about the state of each oceanic region.

The 11 target species are:

1	Trichodesmium
2	Dinophyceae
3	Picocyanobacteria
4	Picoeukaryotes
5	FishUni
6	Haptophyceae
7	Crustaceae
8	Diatom
9	Sardins
10	Anchovy
11	Aurelia

Samples are taken weekly using a custom-made water intake of the ship located below the water line. The sample is then filtered and processed rapidly on-board. A small portable PCR device is used for measuring the abundance of each of the targeted species. Results of that are returned from the PCR device to a cloud portal and data tables are created, with abundance (or how many times a DNA piece affiliated to a species) for each species.

Hundreds of samples have been taken regularly since Statsraad Lehmkuhl departed from Arendal, Norway in August 2021 and this data is now published and accessible by all scientist and citizens of the world. The data are sorted by leg or cruises, representing a certain section of the ocean. So far 8 out of a total of 10 cruises have been completed. The published results contain the timestamp of each sample, the geographical position, and the abundance of each organism found in the sample.

The results can be accessed for further analysis from NMDC (Norwegian Marine Data Centre), see the links below for information about each set of results and information for how to obtain them. The columns in the datasets are as follows:

Assay Date	The date and time the sample was processed
Taxon	The name of the organism – one of 11 selected targets
Abundance	The occurence of each target organism found in the different samples. This can be affiliated to the relative abundance of the organism from sample to sample
Cq	This is the number of cycles required to detect the organism
lat	Latitude coordinate of the location (WGS84)
lon	Longitude coordinate of the location (WGS84)
Fluorophore	This is always SYBR Green for valid results
Assay	An internal “well number” of the sample (range 2-12) for the scientist to identify. This corresponds to the Taxon above.
Quality	A value indicating the quality of the result (range 0-3)