Dynamic, mechanistic, molecular-level modelling of cyanobacteria: Anabaena and nitrogen interaction

Authored by Ferdi L Hellweger, Neil D Fredrick, Mark J McCarthy, Wayne S Gardner, Steven W Wilhelm, Hans W Paerl

Date Published: 2016

DOI: 10.1111/1462-2920.13299

Sponsors: United States National Science Foundation (NSF)

Platforms: No platforms listed

Model Documentation: Other Narrative

Model Code URLs: Model code not found

Abstract

Phytoplankton (eutrophication, biogeochemical) models are important tools for ecosystem research and management, but they generally have not been updated to include modern biology. Here, we present a dynamic, mechanistic, molecular-level (i.e. gene, transcript, protein, metabolite) model of Anabaena - nitrogen interaction. The model was developed using the pattern-oriented approach to model definition and parameterization of complex agent-based models. It simulates individual filaments, each with individual cells, each with genes that are expressed to yield transcripts and proteins. Cells metabolize various forms of N, grow and divide, and differentiate heterocysts when fixed N is depleted. The model is informed by observations from 269 laboratory experiments from 55 papers published from 1942 to 2014. Within this database, we identified 331 emerging patterns, and, excluding inconsistencies in observations, the model reproduces 94\% of them. To explore a practical application, we used the model to simulate nutrient reduction scenarios for a hypothetical lake. For a 50\% N only loading reduction, the model predicts that N fixation increases, but this fixed N does not compensate for the loading reduction, and the chlorophyll a concentration decreases substantially (by 33\%). When N is reduced along with P, the model predicts an additional 8\% reduction (compared to P only).

Tags

Water growth Gene-expression In-silico Blue-green-alga Sp strain pcc-7120 Flos-aquae Glutamine-synthetase Nitrate uptake Cylindrica