Marine Chemical Speciation (MarChemSpec)

Marine Chemical Speciation (MarChemSpec)

Marine Chemical Speciation (MarChemSpec) 1920 1080 Ocean Decade

Lead institution:

University of Gothenburg – Sweden

The project is guided by the vision that the marine science community will have free access to fully documented, state-of-the-art, user-friendly software for chemical speciation calculations, including uncertainty estimates. The chemical speciation models use Pitzer equations for calculating activity coefficients, allowing their application beyond standard seawater conditions, unlike models such as CO2SYS.

These models are freely available, flexible in use, and can be accessed directly or through Python or MATLAB environments. This unique combination of capabilities is based on state-of-the-art thermodynamic data. Two models have been developed.

The first is for Tris buffers in artificial seawater, used for calibrating oceanic pH measurements. This model is crucial for understanding the differences between routine total pH measurements and the thermodynamic definition of total pH, which is the sum of hydrogen ion and bisulfate concentrations. This work is essential for the correct interpretation of oceanic pH measurements and for developing an SI-traceable oceanic pH scale, a priority identified by BIPM and WMO. This model is undergoing further development.

The second model is for the major components of seawater (the seawater electrolyte), used for calculations of the CO2 system (acid-base chemistry). It currently includes the 10 trace metal cations most important as micronutrients, toxins, and tracers of oceanic processes (Al3+, Mn2+, Fe2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+).

Start Date: 02/01/2024
End Date: 31/12/2027

Lead Contact: David Turner (

challenges: 1- Understand and beat marine pollution, 2- Protect and restore ecosystems and biodiversity, 4- Sustainable Ocean Economy
ocean_basins: All Ocean Basins
type_of_action: Project


The Science We Need for the Ocean We Want





Join #OceanDecade

Privacy Preferences

When you visit our website, it may store information through your browser from specific services, usually in the form of cookies. Here you can change your Privacy preferences. It is worth noting that blocking some types of cookies may impact your experience on our website and the services we are able to offer.

For performance and security reasons we use Cloudflare

Enable/disable Google Analytics tracking code in browser

Enable / disable the use of Google fonts in the browser

Enable/disable embed videos in browser

Privacy policy

Our website uses cookies, mainly from 3rd party services. Define your Privacy Preferences and/or agree to our use of cookies.