a bug in the MPB update

[aed-modeller]

libaed-water/src/aed_phytoplankton.F90

Line 1308 in a27a543

_DIAG_VAR_S_(data%id_d_mpb) = mpb

This look like a bug because the variable mpb in this code was the MPB biomass from previous timestep, and was not updated during the calculations, so at the end the MPB biomass is alway the same although growth and respiration were calculated.