Latest News (February 2024)

MarChemSpec at Ocean Sciences 2024, and New Release of Modelling Software

MarChemSpec is the Marine Chemical Speciation Model for acid-base speciation, trace metal complexation, and saturation with respect to solid phases in natural waters containing the inorganic species present in seawater. Project leaders Simon Clegg and David Turner will be present at Ocean Sciences and, to coincide with the meeting, we have a new release of the modelling software. The improvements make it easier to use for many oceanographic applications, and we have also updated the trace metal model to our most recent work. These are the new features:

  • The software is now able to automatically adjust an input solution (seawater or some other natural water) to fixed single values, or pairs, of these quantities: total dissolved inorganic carbon, total alkalinity, total or free pH, and partial pressure or fugacity of CO2. This makes the model simpler to use for many oceanographic and mCDR (marine CO2 removal) applications.
  • Our model of trace metal complexation has been improved for Fe(III) hydrolysis, based on work described in one of our posters (see below). This model does not yet have the new capabilities noted above.

Talk to Us About MarChemSpec Applications

Simon Clegg and David Turner will present posters on MarChemSpec applications to marine carbon dioxide removal (CM24A-1140) and trace metal complexation (OB34C-0880).

Meet Simon and David at their posters, and visit the Ocean Carbon & Biogeochemistry (OCB) Exhibit Booth (BOOTH 512, OSM Exhibit Hall, MAP) to test drive the new software and discuss applications. Their availability at the OCB booth is likely to be broadly:

  • Tuesday: 10 am – 6 pm
  • Wednesday: 10 am – 4 pm
  • Thursday: about 10 am, or 12 noon – 1 pm

To arrange a specific time to meet, please email Simon ( and David (, or talk to Heather Benway or Mai Maheigan at the booth.

Simon will also be attending the Workshop to Build Consensus Toward Science-Led Protocols for Ocean Alkalinity Enhancement (Monday morning, February 19), and the mCDR Networking Event (Monday evening, February 19).

Software Downloads

The new releases of the software can be downloaded (as zip files) from the links below. At this time both the seawater and trace metal models are available only as standalone Windows programs, and as a Windows MATLAB function. (After the meeting we will prepare Linux and macOS standalone models, and the Python function. The software page on this website will also be updated later.)

Unzip the archives to your computer, and follow the instructions in the \docs subdirectories. In the cases of the seawater model and MATLAB function we have provided revised versions of the original instruction manuals, plus shorter Supplements that describe how to use the new features. For the trace metal model, there is just a revised version of the original manual. If you have any problems installing or using the software, please contact us.