The MARDI working group has outlined several objectives for the coming years. The group formally launched in 2023 and will be engaged in activities involving datasets of various marine Arctic sediment records.

  • January 2023 WORKSHOP 1: Establishing protocols

    The first workshop will 1) identify existing Arctic and subarctic diatom-based calibration data sets including surface sediment assemblages and associated environmental surface ocean data and agree upon common criteria for integrating the databases. Additional new sites will adhere to these criteria; here special emphasis will be given to best practices for sampling surface sediment data. 2) Identify the challenges ahead for aligning the taxonomy of the various datasets and outline a plan towards Workshop 2.
  • June 2023 WORKSHOP 2: Taxonomy

    This workshop will be dedicated to integrating and agreeing upon a common taxonomy for all datasets. A key outcome of this workshop will be the outline of the publication of a taxonomic guide that includes descriptions of species ecology, images, and geographical distribution. Workshop 2 will be followed by several online taxonomic workshops on specific taxa during the following months.
  • June 2023 – June 2024 Taxonomic archives

    Gradual collection and archiving of diatom species information to online databases, based on the plans laid out in Workshop 2.
  • July 2024 WORKSHOP 3: Statistical relationships

    This workshop will focus on relating diatom assemblages to environmental data in the Arctic. Participants will include diatomists, data scientists, and experts in quantitative paleoceanography. Key topics include:

    1) integration of samples collected in past decades with recent samples
    2) determination of modern surface samples
    3) evaluation of time integration in surface samples
    4) accessing accurate and time appropriate environmental data
    5) best practices in statistical analyses, transfer functions, and data mining
  • August 2024-September 2025 Synthesis
    Integration of the datasets and association with environmental metadata as agreed in Workshop 3. Construction and publication of the final diatom-based transfer functions.
  • October 2025 WORKSHOP 4: Training
    In this concluding MARDI workshop, the final transfer functions will be presented in the form of a short course. The instructors will outline the principles and the limitations of the approach.


  • Past Global Changes (PAGES)

    Marine ARctic Diatom Working Group


Christof Pearce

Assistant Professor Department of Geoscience, Aarhus University, Denmark

Beth Caissie

Physical Scientist US Geological Survey

Audrey Limoges

Associate Professor Earth Sciences at the University of New Brunswick, Fredericton Canada

Kaarina Weckstrom

Paleoecologist University of Helsinki, Finland

Emilie Arseneault

PhD Student Université Laval

Tiia Luostarinen

Doctoral Researcher Environmental Change Research Unit, Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland

Diana W. Krawczyk

Scientist Greenland Institute of Natural Resources, Greenland

Mimmi Oksman

Geological Survey of Denmark and Greenland, Denmark

Sea ice W Greenland fjord
Arctic gravity coring
Ice diatoms