Population Shift and Ecosystem Response – Krill vs. Salps (POSER)

Project description

The western Atlantic sector of the Southern Ocean (SO) and the northern part of the Western Antarctic Peninsula (WAP) in particular is one of the fastest warming areas on the planet, making this part of the SO to an invaluable observatory for ecosystem responses to climate change. Long-term data sets indicate a significant decrease of sea ice cover leading to shifts on different levels in the WAP region such as a decline in krill abundance in the northern part of the WAP and an increase of salp populations as well as a shift in food quality and quantity. Due to their delicate feeding basket, salps prefer ‘warmer’, ice-free waters with lower phytoplankton concentrations. Krill and salps are among the most important grazers in the SO, occupying completely different ecological and spatial niches. They differ remarkably in their life cycles, their mode of feeding and reproduction, the way they fuel the lower food web by organic matter release and the upper tropic levels as prey and in their importance for the SO-fishery. Therefore, shifts in dominance between these two groups will most likely trigger a cascade of short- and long-term changes in ecosystem structure and function, affecting both the functional biodiversity and biogeochemical cycles in the pelagic system of the western Atlantic sector of the SO. The overall aim of POSER is to understand how krill and salps influence productivity, regeneration of macronutrients (N, P, Si) and micronutrients (FE, Zn, Co, Cu, Cd, Pb) with a special focus on Fe, carbon export and structure of the microbial food web in the western Atlantic sector of the Southern Ocean. The interdisciplinary approach will allow predicting the causal effect of climate induced environmental changes on a) the population dynamics of key players in the pelagic system (krill, salps) and b) the consequences of an abundance shift of these organisms on the lower trophic food web, stoichiometry, and carbon flux. Given the important role of the Antarctic food web in the global ocean, our project has large societal relevance enabling us to predict consequences of global warming for the Southern polar ocean.

Project leader
Prof. Dr. Bettina Meyer, Prof. Dr. Helmut Hillebrand

Prof. Dr. Bettina Meyer and Prof. Dr. Helmut Hillebrand

Prof. Dr. Helmut, Hillebrand (ICBM)
Dr. Stefanie Moorthi (ICBM)
Prof. Dr. Bernd Blasius (ICBM)
Prof. Dr. Bettina Meyer (AWI/ICBM)
Prof. Dr. Scarlett Trimborn (AWI)
Dr. Morten Iversen (AWI/MARUM)

Working groups ICBM
Planktology (Hillebrand)
Biodiversity and biological processes in polar oceans (Meyer)
Mathematic Modelling (Blasius)

Drs Katja Metfies, Christine Klaas (both AWI)

Prof. Dr. Evgeny Pakhomov and Dr. Brian Hunt, University of British Columbia (UBC), Canada,
Prof. Dr. Deborah Steinberg, Virginia Institute of Marine Science (VIMS), USA,
Dr. Marina Monti, Istituto Nazionale di Oceanografia e Geofisica Sperimentale (OGS), Italy.


Financial Support
Ministry for Science and Culture of Lower Saxony (MWK)
The project and the financial support are located at the University of Oldenburg.