Arctic ecosystems are among the most impacted by global warming, meaning that the Arctic Ocean can serve as an indicator for the consequences of climate change, as well as the persistence of biodiversity on our planet. Yet, it is not easy to conduct research in the Arctic: As the northern polar region is difficult to access, expeditions to the Arctic Ocean face significant logistical challenges and that is not the only reason why the region remains one of the most poorly understood environments on earth.
Microbes in the sea ice and the water column are a cornerstone in this ecosystem and play pivotal roles in climate feedbacks and in sustaining food webs, which are central for conservation and ecosystem services. Marine microbes also serve as biological indicators due to their fast adaptive response to environmental change.
From September 2019, the German research icebreaker Polarstern spent a year drifting across the central Arctic frozen into the sea ice. This MOSAiC mission („Multidisciplinary drifting Observatory for the Study of Arctic Climate“) was the largest Arctic expedition in history and was led by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). Hundreds of scientists conducted a range of marine, atmospheric and sea ice-related research and collected samples to gain a better understanding of the role of the Arctic Ocean and its ecosystems in climate processes and improve current climate models.
An international group of molecular biologists (“EcoOmics”) is aiming to catalogue the biodiversity and genetic background of the Arctic marine ecosystem based on the samples collected during the MOSAiC expedition. This will create a foundation for benchmarking biodiversity change in the Arctic Ocean and guide conservation efforts by identifying unique species and assessing their extinction risk. The researchers will sequence all the genetic data from the marine organisms found in the samples collected during the MOSAiC expedition. The project aims to provide the scientific community with an open-access Arctic marine biodiversity resource.
The work of the EcoOmics research team, which is jointly headed by the Alfred Wegener Institute in Bremerhaven and the University of East Anglia (UEA) in the United Kingdom, is supported by a variety of partners, including the Helmholtz Association, the German Research Foundation, the Joint Genome Institute in the USA and the Earlham Institute in the UK. HHU is represented on the project by the Institute for Quantitative and Theoretical Biology, and PhD student Ellen Oldenburg, Dr Ovidiu Popa and head of institute Professor Dr Oliver Ebenhöh.
The HHU group is seeking to identify key components that determine the dynamics of Arctic marine microorganisms. Once the functional roles of the members of the biome have been identified and the material and energy flows through Arctic ecosystems are understood, the role of these flows in global geochemical cycles can be evaluated.
The work focuses on the interaction of bacteria and other plankton organisms associated with microalgae to gain a deeper understanding of the functional relationships of the individual organisms. Ellen Oldenburg: “We are using information about the composition of the microbiomes, the genomic potential and cellular activities of the microorganisms to develop models to improve our understanding of the microbiomes and associated metabolic activities in response to a changing Arctic environment.”
A further aim is to develop predictive models that can be adapted and expanded to cover a broad spectrum of ecosystems. Professor Ebenhöh: “The finished model should reveal the dynamics of the Arctic microbial ecosystem over the annual cycle. We hope the model will provide insights into the mechanisms that stabilise the ecosystem structure and dynamics. We also want to identify the factors that make the ecosystem most vulnerable.
Preliminary findings from the MOSAiC EcoOmics group have now been published in PLOS Biology. The genome dataset reveals a year in the biological life of the Arctic Ocean. This marine habitat represents a treasure trove for discovering novel biological processes, which have evolved under the harsh conditions in the Arctic.
Dr Katja Metfies from the AWI and EcoOmics group coordinator: “This dataset will give us an unprecedented insight into the importance of the sea ice and the associated organisms, and in particular their role in maintaining the functionality of the Arctic marine ecosystem, which is under enormous pressure because of climate change. MOSAiC gives us an important insight into the future of the Arctic ecosystems after 2050, when the Arctic Ocean is expected to be ice-free in summer.”
Professor Dr Thomas Mock from UEA and one of the EcoOmics project leaders: “This is the first and largest effort to sequence the central Arctic Ocean through space and time. This initial sampling of the Arctic Ocean from surface to depth using multiomics technology was carried out by the EcoOmics team. These techniques including the sequencing of genes, genomes, and transcriptomes from natural microbial communities.”
EcoOmics will contribute to the body of knowledge on the concept of the evolution of life on our planet and the consequences of climate change, where polar organisms must also be considered. Those new insights from the timeseries data of the organisms are essential for evaluating the impact, interactions and relations of the Arctic Ocean on our ecosystems.
Thomas Mock, William Boulton, John-Paul Balmonte, Kevin Barry, Stefan Bertilsson, Jeff Bowman, Moritz Buck, Gunnar Bratbak, Emelia J. Chamberlain, Michael Cunliffe, Jessie Creamean, Oliver Ebenhöh, Sarah Lena Eggers, Allison A. Fong, Jessie Gardner, Rolf Gradinger, Mats A. Granskog, Charlotte Havermans, Thomas Hill, Clara J. M. Hoppe, Kerstin Korte, Aud Larsen, Oliver Müller, Anja Nicolaus, Ellen Oldenburg, Ovidiu Popa, Swantje Rogge, Hendrik Schäfer, Katyanne Shoemaker, Pauline Snoeijs-Leijonmalm, Anders Torstensson, Klaus Valentin, Anna Vader, Kerrie Barry, I.-M. A. Chen, Alicia Clum, Alex Copeland, Chris Daum, Emiley Eloe-Fadrosh, Brian Foster, Bryce Foster, Igor V. Grigoriev, Marcel Huntemann, Natalia Ivanova, Alan Kuo, Nikos C. Kyrpides, Supratim Mukherjee, Krishnaveni Palaniappan, T. B. K. Reddy, Asaf Salamov, Simon Roux, Neha Varghese, Tanja Woyke, Dongying Wu, Richard M. Leggett, Vincent Moulton, Katja Metfies: Multiomics in the central Arctic Ocean for benchmarking biodiversity change, PLoS Biology (2022), 17.10.2022