Ulrich Sommer

Rapid shifts of entire ecosystems, termed “regime shifts”, are severe but poorly understood consequences of global change. To understand such shifts, we propose to investigate the processes underlying the Baltic regime shift in the 1980s using archived otoliths. Specifically, we aim to retroactively characterize long-term (1978-2016) changes in benthic vs. pelagic feeding of the top predator cod by applying traditional bulk sulfur and nitrogen stable isotope and novel single compound carbon stable isotope analyses to otolith protein samples for the first time. If successful, the resulting case study will set a precedent for the use of historical sample collections to elucidate biological implications of global change.