A novel cross-disciplinary approach to solve an old enigma: the food-web transfer of the mass-blooming phytoplankter Phaeocystis

Phaeocystis spp. are key primary producers in the world oceans, and seasonally constitute the majority of total pelagic biomass at higher latitudes. The trophodynamics of these algae are therefore of key importance forunderstanding some of the largest ecosystems on Earth. Despite decades of investigations the quantitative knowledge about these algae as food for zooplankton and subsequent productivity of higher trophic levels is limitedand contradictory. Recent results suggests that this is due to large errors in laboratory estimates, methodological difficulties, and lack of knowledge aboutthe influence of chemical signaling including anti-predational metabolites in situ. However, our recently developed molecular methods enable specific quantification of copepods and other zooplankton feeding on Phaeocystis insitu. Based on these, we propose to investigate feeding by the dominating micro- and mesozooplankton in Norwegian waters using a combination of molecular, specific stable isotope analysis and classical approaches. The dynamics of metabolites hypothesized to regulate the feeding on Phaeocystis (chemical signaling) will be simultaneously analyzed using cutting-edge metabolomic approaches. The project is based on a close cooperation by an established group of international leaders in their respective fields, and will develop Norwegian research skills and expertise through focus on training of young scientists in state-of-the-art methodology. To achieve a lasting effort towards gender equality we will promote female candidates combined with national and international network building. We have ambitious publication plans and anticipate considerable national and international interest. This project aims to establish advanced methodologies in quantitative aquatic ecology, and has a significant potential to increase the quantitative understanding of Phaeocystis in the global cycling of climate gases and transfer of energy to higher trophic levels, such as fisheries.