Andreas Oschlies, GEOMAR, Germany
Andreas Oschlies, GEOMAR, Germany


Andreas Oschlies
GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany


An elevated marine oxygen inventory in a warmer future ocean?


An Earth system model of intermediate complexity (UVic) is employed to simulate the impact of global warming on marine oxygen and nutrient budgets to anthropogenic CO2 emissions on millennial timescales. A surprising finding is that the simulated marine oxygen inventory of the warmer future ocean exceeds the preindustrial oxygen inventory for plausible assumptions about biogeochemical processes and circulation dynamics. After an initial deoxygenation period progressing for a few hundred years and leading to a substantial expansion of oxygen minimum zones, oxygen levels start to rise and even exceed preindustrial levels after a few millennia under much warmer climate conditions. Circulation dynamics, thermodynamics and redox-sensitive biogeochemical feedbacks involving the nitrogen cycle explain this unexpected result. Sensitivities of the simulated oxygen increase to uncertainties in assumptions about ocean mixing, marine biogeochemical processes and expected long-term changes in terrestrial weathering and phosphorus input are discussed, as are implications for our understanding of the generation of past oceanic anoxic events.


Time and Place (OBS! The unusual day and time)

Thursday March 22nd 2018, 15.15
Rossbysalen C609, Arrhenius Laboratory, 6th floor