Introducing: Dr. Dana Hellemann

17.6.2019
On June 12, ABRU researcher Dana Hellemann successfully defended her thesis “Nitrogen cycling in aphotic coastal sandy sediments of the Baltic Sea”. She was supervised by Susanna Hietanen and Petra Tallberg and her opponent was Dr. Kirstin Dähnke from the Helmholtz Centre for Materials and Coastal Research Geesthacht, Germany.
Dana with her custus (Jukka Horppila) and her opponent (Dr. Kirstin Dähnke)

left to right: Prof. Jukka Horppila, Dr. Dana Hellemann, Dr. Kirstin Dähnke (Photo credit: Christina Zänker)

Dana investigated Nitrogen cycling in sandy sediments in the aphotic coastal zone of the Baltic Sea. Despite being an important nutrient, the loading of nitrogen to the Baltic Sea exceeds the needs of the ecosystem and thereby promotes eutrophication. The aim of her project was to determine the efficiency of land-derived nitrogen removal in deep coastal sands of the Baltic Sea, e.g. by denitrification. For this purpose, she sampled along a North-South gradient throughout the coastal zone of the Baltic Sea, which included environmental gradients such as trophic status (anthropogenic footprint, nitrogen loading), organic matter quality and quantity, sediment composition. Her results indicate that sandy sediments indeed play an important role in nitrogen removal and retention in the coastal zone of the Baltic Sea. Furthermore, she discovered that nitrogen-cycling rates are strongly influenced by local sources and she thereby emphasizes the need for context dependent data analysis, particularly in a diverse coastal setting such as in the Baltic Sea.

Dana Hellemann with friends and colleagues (left to right: Johanna Gammal, Dana Hellemann, Iines Salonen, Sami Jokinen and Jesse Harrison), Photo credit: Christina Zänker

Dana Hellemann with friends and colleagues (left to right: Johanna Gammal, Dana Hellemann, Iines Salonen, Sami Jokinen and Jesse Harrison)

Dana's work was part of the BONUS project "COCOA: Nutrient Cocktails in the Coastal Zone of the Baltic Sea" and the Academy of Finland project "Biogeochemical links between climate change and eutrophication in the Baltic Sea". The thesis was funded by the Academy of Finland, the BONUS COCOA project (jointly funded by: the European Union, the Academy of Finland, the Onni Talas Foundation and the Finnish Cultural Foundation) and the University of Helsinki.

The e-thesis can be found here:
https://helda.helsinki.fi/handle/10138/301894

ABRU colleague Iines Salonen presents Dana the handcrafted German Doktorhut

Iines Salonen presents Dana her personalized Doctor hat (Photo credit: Christina Zänker)