Project: The role of picophytoplankton in the Arctic carbon cycle

Facts about the project

Project managers
Lisa Winberg von Friesen
Other project members
Hanna Farnelid and Rebecca Duncan, Linnaeus University; Ilka Peeken and Katja Metfies, Alfred Wegener Instititute
Participating organizations
Linneaus University, Alfred Wegener Institute Helmholtz centre for polar and marine research (Germany)
Financier
Swedish Research Council (Vetenskapsrådets öppna utlysning 2023), Carl Trygger Foundation (2024), Linnaeus University (Department of Biology and Environment, 2025), The Swedish King Carl XVI Gustaf’s fund for science, technology and environment (2025)
Timetable
1 January 2025 – 1 April 2027
Subject
Ecology, Biology and Environmental Science (Department of Biology and Environmental Science, Faculty of Health and Life Sciences)
Research group
Marine phytoplankton ecology and applications (MPEA)
Centre of Excellence
Linnaeus University Centre for Ecology and Evolution in Microbial model Systems (EEMiS)
Knowledge Environment
Linnaeus Knowledge Environment: Water

More about the project

Picophytoplankton are the smallest group of phytoplankton (<3 μm) and commonly dominate the community of primary producers in the Arctic. They are key players in the Arctic ecosystem, and in some regions, a shift from larger phytoplankton such as diatoms towards smaller groups is observed. This shift is predicted to continue with the progression of climate change. The role of picophytoplankton in the marine carbon cycle (e.g., how much carbon they fix, what are they regulated by, how much do they sink out of the water column and contribute to the biological carbon pump, and what is their importance as prey item) is still poorly understood in the Arctic in general, and during the autumn season in particular. Better knowledge of the biogeochemical and ecological roles of picophytoplankton in the Arctic Ocean is needed, and this project aims to fill some of those knowledge gaps.

During an Arctic expedition (EGC-Sources, PS150) with RV Polarstern (Alfred Wegener Institute) 2025, we will study the role of picophytoplankton in the Arctic autumn carbon cycle. We will do so by assessing their abundance, primary productivity, and downward export over environmental gradients (e.g., from tidewater glaciers, coastal areas, and in sea ice). Further, we will experimentally quantify and characterize the carbon flow from a key picophytoplankton species (Micromonas polaris) to grazers and into the microbial loop.

The increasing prevalence of autumn phytoplankton blooms  is an important feature with biogeochemical impacts on the overall Arctic Ocean carbon budget and its sequestration potential, as well as ecological impacts and interactions in the ecosystem. Declining sea ice causes increased wind-driven mixing and momentum transfer to the ocean. We will on this basis also experimentally investigate how vertical mixing can impact the development of autumn blooms in our study area by mimicking mixing events and following the ecological and biogeochemical responses of phytoplankton and their primary productivity.

As an overarching framework of our work, we aim to better bridge rate measurements (e.g., primary production) with DNA- and RNA-based molecular approaches (e.g., amplicon sequencing)  by integrating traditional and emerging methods in both observational (e.g., quantification of group-specific Rubisco as a proxy for primary production) and experimental approaches (e.g., performing RNA-stable isotope probing experiments to trace and quantify carbon flux between trophic levels). We will furthermore isolate pelagic and sympagic picophytoplankton for future ecophysiological studies at the Kalmar Algae Collection (KAC) of Linnaeus University in Sweden.

You are welcome to contact us if you are interested in collaborating, performing a student project, or have questions.

The project is part of the research in the research group Marine phytoplankton ecology and applications, in the Linnaeus University Centre for Ecology and Evolution in Microbial model Systems (EEMiS) and in the Linnaeus Knowledge Environment: Water.