Royal Netherlands Institute for Sea Research

Peter Kraal

Tenure track Scientist
Phone number
+31 (0)222 369 455
Ocean Systems (OCS)
Tenure track Scientist


  • Marine (bio)geochemistry
  • Coupled Fe - P - S biogeochemical cycles
  • Sediment redox chemistry - hypoxia/anoxia

Research Interests

I am a marine geochemist investigating the interplay between oxygen availability and the biogeochemical cycling of essential elements such as iron and phosphorus in marine waters and sediments. Globally increasing eutrophication and marine oxygen depletion, often caused or exacerbated by human activities, gets me worried but also scientifically excited.

Moreover, I have developed a strong interest in analytical techniques that push our understanding of this research field forward, such as X-ray absorption spectroscopy for particle characterization and polymer-based passive sampling techniques for high-resolution, two-dimensional porewater analysis.

To understand past and future impacts of marine deoxygenation I investigate the mineralogy, chemical composition and fluxes in modern surface sediments as well as the chemical signature of oxygen depletion in historical sediment records. A particular interest of mine is the impact of (changing) chemical conditions on the stability of authigenic minerals.

Education and Experience

2015 - 2017 NWO-Veni postdoctoral fellow at Utrecht University - Department of Earth Sciences-Geochemistry; Iron mineral transformations and preservation: Effects of eutrophication-driven changes in sediment geochemistry

2013 - 2014 Postdoctoral researcher at Utrecht University - Department of Earth Sciences-Geochemistry; Coupled cycling of iron, phosphorus and manganese in the Black Sea

2011 - 2013 Postdoctoral researcher at Southern Cross University - Geosciences; Hyperaccumulations of monosulfidic sediments: Exploring a biogeochemical extreme to resolve fundamental sulfur biomineralisation pathways

2006  -2010 PhD student at Utrecht University - Department of Earth Sciences-Geochemistry; Redox-dependent phosphorus burial in modern and ancient marine sediments

Research expeditions

I have been involved in various research cruises, during which I collected and processed (anoxic) water column and sediment samples for on-board and on-shore analyses.

September 2015 | "Fe Vici" cruise to the Black Sea with r/v Pelagia, along a gradient from the oxic shelf to the sulfidic deep basin

September 2014 | Short cruise with r/v Mare Nigrum to the deep northwestern Black Sea to collect sediment traps

June 2013 | "PhOxy" cruise to the Black Sea, along a gradient from the oxic shelf to the sulfidic deep basin

2011 - 2012 | Various samping trips to the shallow Peel-Harvey Estuary in Western Australia

May/June 2009 | "HYPER" cruise to the Baltic Sea with r/v Aranda to the Baltic Sea

August/September 2007 | Cruise to the Baltic Sea with r/v Skagerrak