Results from simulations with the coarse-resolution version of MPI-ESM performed by the RETRO team at DKRZ. The left side shows a normal (prograde) rotating earth. The right side shows a backwards (retrograde) rotating earth. The simulations are forced with pre-industrial boundary conditions. For the full description see the Earth System Dynamics manuscript "The climate of a retrograde rotating earth". N*=NO3-16PO4 is a measure for denitrification resulting when bacteria use nitrate instead of oxygen to degrade organic matter. Negative values of N* indicate lack of nitrate and abundance of phosphate. This process of denitrification occurs only in oxygen minimum zones. It reveals its implication on biological productivity of most marine plants when water with low N* values reaches the surface and limits plant growth. In the retrograde simulation (right) very low values of N* are found in the Indian Ocean.