Publication Details

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Title (Primary) Algal internal nutrient stores feedback on vertical phosphorus distribution in large lakes
Author Frassl, M.A.; Rothhaupt, K.-O.; Rinke, K.;
Journal Journal of Great Lakes Research
Year 2014
Department SEEFO;
Volume 40
Issue Suppl. 3
Language englisch;
POF III (all) T32;
Keywords Lake model; Droop; Monod; Nutrient limitation; Stoichiometry; DYRESM-CAEDYM
UFZ wide themes RU2;
Abstract

We applied a coupled hydrodynamic-ecological lake model to Lake Constance and investigated the consequences of luxury uptake of mineral resources (phosphate) by phytoplankton on the distribution of this resource in the environment. We compared two different resource limitation models, a static P model with a fixed cell stoichiometry disabling luxury uptake (the Monod approach) and a dynamic P model with a flexible cell stoichiometry enabling luxury uptake (the Droop approach). Our research was based on the finding that a model simulation using the static P model showed good results for phytoplankton dynamics but was unable to simulate the vertical distribution of the algal resource properly. In this model, the resource was only depleted in the euphotic zone (ca. 0–20 m) while in Lake Constance observed phosphate depletion was about twice as deep (down to ca. 40–50 m).

A simulation using a dynamic P model reproduced the vertical extension of resource depletion. The driving process behind the deeper resource depletion was luxury uptake of phosphate by algae sedimenting out of the productive zone. Even though the spatial extent of phosphate depletion strongly differed, the difference in phytoplankton dynamics between the two resource limitation models was minor.

It is shown that a process acting at the cellular level has wide implications at the ecosystem level. Thereby, the inclusion of a flexible cell stoichiometry of phytoplankton into a complex lake model is important for predicting spatial nutrient gradients within the lake.

ID 15267
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=15267
Frassl, M.A., Rothhaupt, K.-O., Rinke, K. (2014):
Algal internal nutrient stores feedback on vertical phosphorus distribution in large lakes
J. Gt. Lakes Res. 40 (Suppl. 3), 162 - 172