Document Type


Publication Date




Publication Title

Biogeosciences Discussions


In Review


39 pp.


Arctic coastal ecosystems are rapidly changing due to climate warming, which makes modelling their productivity crucially important to better understand future changes. System primary production in these systems is highest during the pronounced spring bloom, typically dominated by diatoms. Eventually the spring blooms terminate due to silicon or nitrogen limitation. Bacteria can play an important role for extending bloom duration and total CO2 fixation through ammonium regeneration. Current ecosystem models often simplify the effects of nutrient co-limitations on algal physiology and cellular ratios and neglect bacterial driven regeneration, leading to an underestimation of primary production. Detailed biochemistry- and cell-based models can represent these dynamics but are difficult to tune in the environment. We performed a cultivation experiment that showed typical spring bloom dynamics, such as extended algal growth via bacteria ammonium remineralisation, and reduced algal growth and inhibited chlorophyll synthesis under silicate limitation, and gradually reduced nitrogen assimilation and chlorophyll synthesis under nitrogen limitation. We developed a simplified dynamic model to represent these processes. The model also highlights the importance of organic matter excretion, and post bloom ammonium accumulation. Overall, model complexity is comparable to other ecosystem models used in the Arctic while improving the representation of nutrient co-limitation related processes. Such model enhancements that now incorporate increased nutrient inputs and higher mineralization rates in a warmer climate will improve future predictions in this vulnerable system.


© Author(s) 2020.

This work is distributed under the Creative Commons Attribution 4.0 License.

Data Availability

Article states: "The experimental data are archived at DataverseNO under the doi number The Rscripts for the model are available from the corresponding author upon request."

Corresponding authors: Tobias R. Vonnahme (ORCiD:; Christoph Voelker

Data with DOI as referenced in the article can be found at the following link:


Note: this is a preprint. Published article is available online at

Original Publication Citation

Vonnahme, T. R., Leroy, M., Thoms, S., van Oevelen, D., Harvey, H. R., Kristiansen, S., Gradinger, R., Dietrich, U., & Voelker, C. (2020). Modelling Silicate - Nitrate - Ammonium co-limitation of algal growth and the importance of bacterial remineralisation based on an experimental Arctic coastal spring bloom culture study. Biogeosciences Discussions, In Review, 1-39.


0000-0001-7746-7758 (Harvey)