Iron is a most important micronutrient for oceanic phytoplankton production. In Southern Ocean, wide areas are low-productive due to scarcity of iron despite high concentrations macronutrients. Iron availability decreases by distance from continent and increases again in seasonal sea-ice zone as ice releases iron. Bacteria are better in low concentration nutrient uptake and in offshore waters bacteria contain most of the biogenic iron. Many small unicellular algae are mixotrophic, i.e. they can prey on iron rich bacteria and photosynthetize. This route for iron is not well known. In IMICROBE we study the role of bacterial iron in regulation of primary productivity of the Southern Ocean across major habitats from subtropical to seasonal sea-ice zone onboard research vessel. The project will look at bacterial capacity for iron uptake at molecular level, presence and grazing activity of mixotrophic protists and combine it with development of advanced biogeochemical ocean modelling.

2021

2024