2020 | Sweden | Erika Eriksson

Phytoplankton and Thiamine

Water issue adressed: Too little

Thiamine deficiency has recently been identified as a massive threat to ecosystems in the Northern Hemisphere and in the Baltic region. It has been suggested that phytoplankton might be at the core of the problem and that auxotrophy regarding thiamine might make a difference to the dynamics of ecosystems. The purpose of this work was to examine the growth of phytoplankton in water enriched with thiamine, with the aim to investigate the share of thiamine auxotrophs in the Baltic Sea. In the present study the growth of phytoplankton in thiamine-enriched water has been observed by primary adding plant nutrient to water collected from the Baltic Sea. Half of the water was then enriched with thiamine while the other half was not. The water was divided into 16 Erlenmeyer flasks and left to grow. Three days later the samples were filtered with suction and the filter papers were then placed in acetone for overnight extraction. The acetone was spectrophotometrically analysed and the concentration of chlorophyll a in the samples was calculated. The experiment showed that the concentration of chlorophyll a, after the period of growth, was significantly higher (ANOVA, p=0.05) in the water enriched with thiamine than in the water that was not. This implicated that the share of thiamine auxotrophs among the phytoplankton was large at the time the experiment was carried out. The composition of phytoplankton-species in the Baltic Sea is still to be examined more closely. In conclusion, this study serves to draw attention to the underlying causes of thiamine deficiency and as an inspiration for further research in this area.

Project video

This is how I came up with the idea for this project:

My interest in thiamine deficiency has developed over many years. When reseaching this topic I encountered auxotrophy and since it was an interesting part of the dynamics in a phytoplankton community I decided to examine the share of thiamine auxotrophs in the Baltic Sea.


Ania Andersch

Programme manager ania.andersch@siwi.org +46 8 121 360 59