diff --git a/unchanged/marbl_interface_private_types.F90 b/unchanged/marbl_interface_private_types.F90
index a8529ea..9d75721 100644
--- a/unchanged/marbl_interface_private_types.F90
+++ b/unchanged/marbl_interface_private_types.F90
@@ -405,6 +405,7 @@ module marbl_interface_private_types
      integer(int_kind) :: salinity_id    = 0
      integer(int_kind) :: pressure_id    = 0
      integer(int_kind) :: fesedflux_id   = 0
+     integer(int_kind) :: docfluidy_id   = 0
      integer(int_kind) :: o2_consumption_scalef_id = 0
      integer(int_kind) :: p_remin_scalef_id = 0
 
@@ -616,6 +617,8 @@ module marbl_interface_private_types
     integer(int_kind) :: Lig_photochem
     integer(int_kind) :: Lig_deg
     integer(int_kind) :: fesedflux
+    integer(int_kind) :: docfluidy
+
 
     ! Particulate 2D diags
     integer(int_kind) :: POC_FLUX_at_ref_depth
@@ -1756,6 +1759,10 @@ subroutine interior_tendency_forcing_index_constructor(this,
       forcing_cnt = forcing_cnt + 1
       this%fesedflux_id = forcing_cnt
 
+      ! DOC fluid Flux
+      forcing_cnt = forcing_cnt + 1
+      this%docfluidy_id = forcing_cnt
+
       ! O2 Consumption Scale Factor
       if (lo2_consumption_scalef) then
         forcing_cnt = forcing_cnt + 1