MBL GEM Download Page

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The Marine Biological Laboratory’s General Ecosystem Model (MBL GEM) was written in Borland Delphi for IBM PC compatibles. If you want to make changes to the MBL GEM equations you will need Borland Delphi, otherwise you do not.

Each version of MBL GEM is packaged into a zip file. The zip file contains the full source code, the MBL GEM Windows executable, and sample parameter and driver files. Before running MBL GEM unzip the files into an empty directory.

Unless explicitly stated otherwise, parameter files created in one version of the MBL GEM are not compatible with another version.

Acceptable Use Policy

The software provided on this page has been tested under the Windows NT, XP and 7 operating systems. However, its stability under all conditions cannot be guaranteed. The user assumes all risk for its use.

Downloading and using the software requires that:

  1. The Principal Investigator is sent a notice stating the model version downloaded.
  2. The user regularly checks this web site for updated software.
  3. The Principal Investigator of the model be sent a copy of the report or manuscript prior to submission and be adequately cited in any resultant publications.
  4. A copy of any resultant publications should be sent to:

Edward Rastetter
Ecosystems Center
Marine Biological Laboratory
Woods Hole, MA 02543

Versions Available for Download


MBL GEM Version 6.4.4.5

Daily GEM with vegomatic

Updated 27 May 2005

Modified fonts, etc so that windows and dialogs size properly on laptops and other aesthetic changes.

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, Update 1.Uses TMS Softwares TAdvstringgrid File: MBLGEMv6445 Relevant Citations: Unpublished

MBL GEM Version 6.4.4.3

Daily GEM with vegomatic

Updated 28 February 2005

Parameter files created in version 6.4.4.1 should be compatible with this version but the user should check the model output to make sure.

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, Update 1
Uses TMS Softwares TAdvstringgrid version
File: MBLGEMv6443 Relevant Citations: Unpublished

MBL GEM Version 6.4.4.1

Daily GEM

Updated 20 May 2003

Added annual respiration for each tissue, humus C:N and active soil C. Corrected bugs in the append to output file option

Parameter files created in gemv644 are not compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid version
File: MBLGEMv6441 Relevant Citations: Unpublished

MBL GEM Version 6.4.4

Daily GEM

Updated 15 May 2003

Added annual NPP for each tissue. Added the ability to append to the output file.

Parameter files created in gemv6433 are not compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid version 2.8.8.0
File: MBLGEMv644 Relevant Citations: Unpublished

MBL GEM Version 6.4.3.3

Daily GEM

Updated 2 April 2003

Corrected calculation of heartwood litter when heartwood is zero.

Parameter files created in gemv6432 are compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid
File: MBLGEMv6433 Relevant Citations: Unpublished

MBL GEM Version 6.4.3.2

Daily GEM

Updated 24 March 2003

Corrected initialization of three cumulative processes.

Parameter files created in gemv6431 are compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid
File: MBLGEMv6432 Relevant Citations: Unpublished

MBL GEM Version 6.4.3.1

Daily GEM

Updated 18 March 2003

Changed the allocation equations. Updated Et equations. Fixed minor bugs in modelshell.

Parameter files created in gemv642 are not compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid
File: MBLGEMv6431 Relevant Citations: Unpublished

MBL GEM Version 6.4.2

Daily GEM

Updated 16 December 2002

Added ability to modify parameters from within the chart, to automatically show chart, to run the model to steady state, to change the output offset, and to output only the end of the run.

Parameter files created in gemv641 are compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid
File: MBLGEMv642 Relevant Citations: Unpublished

MBL GEM Version 6.4.1

Daily GEM

Updated 3 December 2002

Changed transport, growth, and litterfall equations to improve model stability.

Parameter files created in earlier versions are not compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid
File: MBLGEMv641 Relevant Citations: Unpublished

MBL GEM Version 6.3.1

Daily GEM

Updated 2 October 2002

Corrected 7 October 2002

GEM v6.3.0 with correction to N fixation equation

Parameter files created in earlier versions are not compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid
File: MBLGEMv631 Relevant Citations: Unpublished

MBL GEM Version 6.3.0

Daily GEM

Updated 6 June 2002

Daily model that includes simplified allocation and growth models, inhibition of C and N uptake and fixation. Updated the root growth response and corrected litterfall partitioning equations.

Parameter files created in earlier versions are not compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1
Uses TMS Softwares TAdvstringgrid
File: MBLGEMv630 Relevant Citations: Unpublished

MBL GEM Version 3.3.6.5.d

Annual GEM using ACM photosynthesis submodel.

Includes code for hillslope calculations.

Parameter files created in earlier versions are not compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, update 1 File: MBLGEMv3365d Relevant Citations: Rastetter et al., 2004

MBL GEM Version 3.3.6.5.b

Annual GEM using ACM photosynthesis submodel.

Parameter files created in earlier versions are not compatible with this version

Contains: MBL GEM program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, Update 1 File: MBLGEMV3365b Relevant Citations: Le Dizès et al., 2003

AGET - Soil Water Model

Updated 15 September 2000

The AGET model is a daily soil water model currently under development. This version of AGET includes daily submodels of decomposition and photosynthesis.

Parameter files created in earlier versions are not compatible with this version

Contains: AGET program, source code, sample parameter files and driver files and Word documentation. Created in: Delphi 5, Update 1 File: SoilWater Relevant Citations: Unpublished

This material is based upon work supported by the National Science Foundation under grants #OPP-9318529, OPP-9732281, DEB-9509613, and DEB-0108960 and the Environmental Protection Agency under grants RFQ-RT-00-00107 and QT-RT-00-001667. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the Environmental Protection Agency.


Last Updated: 24 March 2015 BK

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