SUBROUTINE ice_bio_conserv(kideb,kiut,ntra,message,trc_nam,err,
     &                           zmb0,zmb1,zfb,zfsu,zdt)

! This routine tests conservation of the mass of tracers
! (c) Martin Vancoppenolle, June 2007
 
      INCLUDE 'type.com'
      INCLUDE 'para.com'
      INCLUDE 'bio.com'

      CHARACTER(len=15) :: 
     &   message       ! : message indicating the name of the routine calling

      CHARACTER(len=64), DIMENSION(ntra_bio_max) :: 
     &   trc_nam       ! : name of the tracer tested

      CHARACTER(len=19) ::
     &   zstr1
      CHARACTER(len=3) ::
     &   zstr2
      CHARACTER(len=8) ::
     &   zstr3

      REAL(8) ::
     &   err

      REAL(8), DIMENSION(ntra_bio_max) ::
     &   zmb0 ,
     &   zmb1 ,
     &   zfb  ,
     &   zfsu

      REAL(8) ::
     &   zdt 
         
      INTEGER :: 
     &   ji          , ! : index for space
     &   jk          , ! : index for ice layers
     &   jn            ! : index for tracers

      REAL(8) ::
     &   zdm           ! : actual mass variation
     &   zdmf

!=============================================================================!

      WRITE(numout,*) ' ice_bio_conserv : '
      WRITE(numout,*) ' ~~~~~~~~~~~~~~~ '
      WRITE(numout,*) ' message     : ', message
      WRITE(numout,*) ' error max   : ', err
      WRITE(numout,*) ' kideb, kiut : ', kideb, kiut
      WRITE(numout,*) ' ddtb        : ', zdt

      DO jn = 1, ntra

         IF ( flag_active(jn) ) THEN
         
          WRITE(numout,*) ' --- Tracer     : ', trc_nam(jn)
          WRITE(numout,*) ' jn : ', jn
          WRITE(numout,*) ' mt_i_bio_init  : ', zmb0(jn)
          WRITE(numout,*) ' mt_i_bio_final : ', zmb1(jn)
   
          zdm = ( zmb1(jn) - zmb0(jn) ) / zdt
          zdmf = zfb(jn) + zfsu(jn)
   
          WRITE(numout,*) ' Actual mass variation zdm       : ', zdm
          WRITE(numout,*) ' Mass variation from fluxes zdmf : ', zdmf
          zstr1 = ' Bio conserv error '
          zstr2 = TRIM(trc_nam(jn))
          WRITE(zstr3,'(E8.2)') ABS(zdm-zdmf)
!         WRITE(numout,*) ' Bio conserv error : ', ABS(zdm-zdmf)
          WRITE(numout,*) zstr1//'in '//TRIM(message)//' ('//zstr2//
     &                    ') : '//zstr3
          WRITE(503,*) zmb1(jn), ABS(zdm-zdmf)*zdt
            
          IF ( ABS ( zdm - zdmf ) .GT. err ) THEN
           WRITE(numout,*) ' Conservation error after ', message
           WRITE(numout,*) ' Error                           : ', 
     &                      ABS( zdm - zdmf )
!           WRITE(numout,*) ' Actual mass variation zdm       : ', zdm
!           WRITE(numout,*) ' Mass variation from fluxes zdmf : ', zdmf
           WRITE(numout,*)
           WRITE(numout,*) ' mt_i_bio_init   : ', zmb0(jn)
           WRITE(numout,*) ' mt_i_bio_final  : ', zmb1(jn)
           WRITE(numout,*) ' Upper flux zfsu : ', zfsu(jn)
           WRITE(numout,*) ' Lower flux zfb  : ', zfb(jn)
           WRITE(numout,*)
!           WRITE(numout,*) ' c_i_bio   : ', ( c_i_bio(jn,layer), 
!    &                      layer = 1, nlay_bio )
!           WRITE(numout,*) ' cbu_i_bio : ', ( cbu_i_bio(jn,layer), 
!    &                      layer = 1, nlay_bio )

          ENDIF ! residual

         ENDIF ! flag_active

      END DO ! jn

      RETURN

!=============================================================================!
!-- End of ice_bio_conserv --
 
      END