Royal Netherlands Institute for Sea Research
Royal Netherlands
Institute for Sea Research

There’s something fishy about phosphorus cycling in the oceans

Phosphorus (P) is an essential element for all life on Earth. In the oceans, P availability controls the growth of photosynthetic micro-organisms and thereby regulates atmospheric CO2 uptake and eventually global climate. In modern coastal systems impacted by humans, high P input can lead to excessive algal blooms and water quality issues. The only way by which P is removed from the water column is by burial in the sediment. The burial efficiency is strongly dependent on the form in which P is deposited on the seafloor, and on the conditions under which this occurs. Fish bones contain a lot of P and, in areas with high biological activity, these bones can represent an important P reservoir in the sediment. In addition, the P minerals in fish bones are very reactive and affect the burial of other important (nutrient) elements such as trace metals. The problem is: this potentially important sediment component is almost never properly investigated and thus its role in P cycling remains unclear.
In this project, we want to constrain the role of fish bones as P (and trace metal) reservoir in marine sediments. We have cores from a variety of contrasting (and fascinating!) marine environments such as the dynamic North Sea, the eutrophic Gulf of Mexico, the oxygen-depleted southeast Atlantic Ocean and the anoxic Black Sea. Fish bones will be identified, isolated and analyzed to quantify how much P and trace metals they carry. For this, we will use chemical methods as well as advanced microscopic and spectroscopic methods. The relative contribution of fish bones to the sedimentary reservoirs of P and trace metals will be determined and placed in the context of environmental conditions. The work has the potential to provide novel insights into marine biogeochemical cycles.
We’re looking for motivated MSc students in environmental, chemical or geosciences. If this is something you would like to do, then please contact us. Within the project you would do both lab work and data analysis. You would be based at NIOZ Royal Netherlands Institute for Sea Research on Texel. Length of the project is approximately 6 months (time interval can be discussed; project goals will be set accordingly).

More information & contact
For more information and to apply, please contact the project supervisors Dr. Peter Kraal ( or Kristin Ungerhofer (