EGU22-9444
https://doi.org/10.5194/egusphere-egu22-9444
EGU General Assembly 2022
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Coupling and decoupling of carbon, oxygen, and nitrogen in the Elbe Estuary

Mona Norbisrath1,2, Johannes Pätsch1,3, Kirstin Dähnke1, Tina Sanders1, Gesa Schulz1,4, Justus E. E. van Beusekom1,5, and Helmuth Thomas1,2
Mona Norbisrath et al.
  • 1Helmholtz-Zentrum Hereon, Institute of Carbon Cycles, Geesthacht, Germany (mona.norbisrath@hereon.de)
  • 2Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
  • 3Institute of Oceanography, University Hamburg, Hamburg, Germany
  • 4Institute of Geology, Center for Earth System Research and Sustainability (CEN), University Hamburg, Hamburg, Germany
  • 5Institute for Marine Ecosystem and Fishery Science, University Hamburg, Hamburg, Germany

The Elbe Estuary and its biogeochemistry are strongly influenced by tidal cycles of the North Sea, high nutrient and organic matter loads from the catchment area, and dredging of the navigation channel to maintain the connection between the North Sea and Germanys largest seaport in Hamburg.

Due to large phytoplankton blooms upstream of the port, the input of organic matter is high and provides high metabolic activity within and downstream the Hamburg port.

Here, we combined carbon, oxygen, and nitrogen data to elucidate their relationship and distribution along the Elbe Estuary. We used a box model approach to balance the budgets of dissolved inorganic carbon (DIC), oxygen (O2), and nitrogen in form of nitrate (NO3-). To complete carbon and oxygen, we included atmospheric exchange of carbon dioxide (CO2) and O2.

DIC generation and O2 consumption reveal the highest metabolic activity in the Hamburg port area, decreasing downstream. In contrast, NO3- budgets are stable along the estuary, indicating a strong decoupling of carbon and nitrogen in the Elbe Estuary. This decoupling can be explained by anaerobic processes such as denitrification in the port area, but it also implies lateral nitrogen sources further downstream.

How to cite: Norbisrath, M., Pätsch, J., Dähnke, K., Sanders, T., Schulz, G., van Beusekom, J. E. E., and Thomas, H.: Coupling and decoupling of carbon, oxygen, and nitrogen in the Elbe Estuary, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9444, https://doi.org/10.5194/egusphere-egu22-9444, 2022.