The SEACHANGE Copenhagen team collects new sediment cores from the Danish North Sea
At the end of September 2023, members of the Copenhagen SEACHANGE team (Giulia Zampirolo and Luke E. Holman) embarked on a new sampling campaign in the Jutland Peninsula to collect new sediment cores from the North Sea. Our research aims to investigate the genetic traces of past marine ecosystems to address the impacts of marine exploitation both before and during the transition to agriculture (~5900 years BP) by applying the latest advances in ancient environmental genomics.
The Expedition aboard the AURORA Vessel
Thanks to a collaboration with the Department of GeoScience, University of Aarhus, we had the opportunity to board the Aarhus University's research vessel, AURORA, together with Christof Pearce, Katrine Juul Andresen, and their team. We raised the anchor to Aarhus Bay (Kalø Vig, Denmark) on the morning of the 28th of September 2023.
University of Aarhus' RV Aurora
A sub-bottom profiler was first used to provide images of the subsurface morphology before proceeding with coring. The gravity corer, with a weight of around 1.1 tonnes and equipped with a core catcher, a 6-meter-long metal barrel, a PVC tube, and lead plates, allowed us to collect 6 meters of sediments in only half a day.
The gravity corer after deployment in Aarhus Bay
After retrieving the gravity corer, the PVC tube was cut every meter, marked, and sealed for transport to the Department of GeoScience (Aarhus University). Here, the six tubes were split, and high-resolution photographs were taken.
Christof, Giulia, and Luke cutting and sealing the fresh sediment core from Kalø Vig.
Subsampling archived gravity cores from the North Sea
In October 2023, we proceeded with the subsampling for ancient DNA analysis of the fresh core from Kalø Vig, alongside three additional archived cores collected by the Department of GeoScience (Aarhus University) between 2017 and 2018 from Kalø Vig, Vejle Fjord, and Limfjord. The archived cores, still in good condition, were of substantial interest given their location within the Jutland Peninsula and their existing chronology, which extended to over 8000 years before the present.
A total of 329 samples were collected in a dedicated room at the Department of GeoScience, using a full protective suit and gloves, to prevent DNA contamination. The surfaces of the split cores were scraped with sterilised scalpels to remove any potential contamination from adjacent layers and the sediment was extracted using sterilised syringes. Samples were transported to the University of Copenhagen and stored at -20 C. Macrofossils, for example, visible plant material and shells, were also selected and sent for radiocarbon dating (C14) to the CHRONO Lab (Belfast, UK). This will allow the construction of age-depth models to support the metagenomic data.
Subsampling sediments for ancient DNA analyses and macrofossils for radiocarbon (C14) dating.
A total of 100 samples were selected for preliminary ancient DNA extraction and amplification at the GeoGenetics Sequencing Core (University of Copenhagen). Around 2.5 billion DNA sequences were generated and are currently under analysis.
Giulia, Luke, and the student crew aboard the AURORA vessel
A special thank you to Christof Pearce, and Katrine Juul Andresen (Department of GeoScience, Aarhus University) for inviting us to join their research vessel and work on this valuable sediment material! A huge thanks to the dedicated crew and students helping out!
