Process-Based modelling of Shallow Aquatic Microcosms Reveals Adaptation of Phototrophic Communities to Agricultural Run-off and Warming - Université de Lorraine Access content directly
Poster Communications Year : 2023

Process-Based modelling of Shallow Aquatic Microcosms Reveals Adaptation of Phototrophic Communities to Agricultural Run-off and Warming

Abstract

Surface run-off transports nutrients and pesticides from agricultural sites into nearby shallow aquatic ecosystems that are dominated by different primary producer groups: submerged macrophytes, periphyton or phytoplankton. Agricultural run-off (ARO) can induce shifts from a macrophyte-dominated to a phytoplankton-dominated state, which may alter or impair their ecological functioning and services. Global warming may further increase the risk of these ARO-induced shifts. A microcosm experiment mimicking ARO effects on shallow aquatic systems with different primary producer groups was combined with process-based modelling to test three hypotheses: 1) Differences in the vulnerability of different primary producers to ARO increase the risk of shifts to a phytoplankton-dominate state; 2) warming further increases this risk; 3) process-based modelling supports mechanistic understanding of ARO effects on primary producers through comparison of different scenarios. A simplified shallow aquatic system containing different primary producer groups (phytoplankton, periphyton, submerged macrophytes) was exposed to a gradient of ARO (five different concentrations of a mixtures of nitrate, an herbicide, an insecticide, a fungicide, copper) at two different temperatures, 22°C and 26°C, for three weeks. A tailor-made process-based model was used to test eight different scenarios, targeting different temperature-dependent growth rates, herbicide sensitivities and community adaptation to pesticides. In the experiment, ARO had negative effects on macrophytes while phytoplankton was positively affected. Warming further enhanced phytoplankton growth. Comparing model scenarios with the observed results revealed that the best quantitative and qualitative fit was achieved when community adaptation of phytoplankton was considered with lower herbicide sensitivity at higher temperature. Our study highlights the benefits of combining process-based modelling with experiments to disentangle and mechanistically understand effects of multiple stressors in shallow aquatic systems. Warming and ARO were shown to potentially lead to a shift from macrophyte dominance to phytoplankton dominance, and fast phytoplankton community adaptation to pesticides contributed to this effect.
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Dates and versions

hal-04133266 , version 1 (19-06-2023)

Identifiers

  • HAL Id : hal-04133266 , version 1

Cite

Bastian Herbert Polst, Gregorio Alejandro López Moreira Mazacotte, Elisabeth Maria Gross, Mechthild Schmitt-Jansen, Franz Hölker, et al.. Process-Based modelling of Shallow Aquatic Microcosms Reveals Adaptation of Phototrophic Communities to Agricultural Run-off and Warming. SETAC EUROPE 33RD ANNUAL MEETING, Apr 2023, Dublin, Ireland. ⟨hal-04133266⟩
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