Royal Netherlands Institute for Sea Research

Ocean acidification and air-sea CO2 exchange in the Dutch North Sea

The ocean absorbs a quarter of human CO2 emissions each year, significantly reducing our impact on Earth’s climate. The North Sea plays an important role in this CO2 uptake through the ‘continental shelf pump’ mechanism. However, the extra CO2 lowers seawater pH: ocean acidification. This can have negative consequences for a variety of marine species and ecosystems, especially those that form their shells and skeletons from calcium carbonate, from microscopic plankton at the base of the food web up to oysters and coral reefs.

In collaboration with Rijkswaterstaat, we perform monthly measurements of key biogeochemical parameters including pH at a series of sampling stations across the Dutch North Sea. These data are reported annually as a national contribution to UN Sustainable Development Goal 14, Life Below Water (

The aims of this project are:

  • to determine the physical and biogeochemical controls on seawater pH and air-sea CO2 exchange, as recorded by the growing Rijkswaterstaat-NIOZ dataset; and,
  • to map these properties over the entire Dutch North Sea as they vary through time.

In other words, we want to ‘join the dots’ of the sampling stations to draw a continuous picture of the constantly evolving chemical state of the ocean, based on a solid understanding of the underlying Earth system processes. Satellite data and model output will help fill in the gaps between observations in this complex and highly variable environment. The data visualisations produced in this project will be invaluable for communicating the impact of this monitoring programme, not only within the scientific community, but also to policymakers and in outreach to the general public.


We seek a highly motivated Masters student looking for a research project of 6+ months with a strong interest in present-day ocean biogeochemistry and its role in the carbon cycle and Earth’s climate. Data analysis and mapping will be done mainly using Python. Previous experience of Python is not required, but willingness and aptitude to learn are essential; training will be provided. The student may also gain lab experience at NIOZ Texel in the relevant measurement techniques (optional). Timing is flexible, as is the main work location (NIOZ Texel or remote).


Please contact Dr Matthew Humphreys (NIOZ Texel; and/or Prof Dr Gert-Jan Reichart (NIOZ Texel/Utrecht University; for any questions or further information.