ENAC Seminar Series by Dr. Robert Ladwig
16:00 – 17:00 – Dr. Robert Ladwig
Postdoctoral Research Fellow, University of Wisconsin‐Madison, USA
Exploring lake metabolism phenology through modeling: How physics and ecology drive an emergent lake ecosystem property
The availability of dissolved oxygen in lakes governs ecological habitats and niches, redox reaction rates, and the decomposition of organic matter. Although proximal control over lake dissolved oxygen can be attributed to metabolism and physical processes, how those processes evolve over decades largely remains unexplored and there is much to be learned about the interactions of external drivers with internal processes that control metabolic patterns. As global change will affect in-lake metabolism significantly by decreasing oxygen solubility, enhancing respiration and primary production, and limiting vertical transport, robust approaches that combine observational data with process-based models are required to understand potential future changes in lake health.
In this talk, I will present three studies that applied different aquatic ecosystem modelling approaches to analyze long-term change of dissolved oxygen in lakes. By applying a vertical 1D lake model to quantify year-to-year dynamics of anoxia in an urban eutrophic lake, we found that anoxia variability is influenced primarily by physical processes, and less so by processes that influence organic matter decomposition. In the second study, a metabolism model framework was applied to multiple lakes in Wisconsin spanning a range of lake characteristics to investigate change in metabolism phenology. We found that landscape-related differences in metabolism between the forested lakes in the north and the urban lakes in the south are likely related to trophic states as well as hydrology. The third study showcases how hybrid modeling can improve aquatic ecosystem projections by combining process-based models with data-driven methods. By using high-frequency data directly in a modularized model framework, we can estimate challenging model parameters and processes while still getting physically valid results due to the process-based model framework.
Short bio:
Robert Ladwig is a physical limnologist and currently a Postdoctoral Research Fellow at the Center for Limnology at the University of Wisconsin-Madison. Dr. Ladwig received his Ph.D. jointly between the Leibniz-Institute of Freshwater Ecology and Inland Fisheries and the Chair of Water Resources Management and Modeling of Hydrosystems at the Technical University of Berlin. As a Visiting Researcher at Saitama University in Japan, he worked on improving mitigation strategies to prevent the formation of harmful algal blooms in reservoirs. His work explores linkages between physical and biogeochemical processes, and the influence on aquatic ecosystem's biology and ecosystem function through the use of cutting-edge data-intensive and computationally demanding techniques. As an advocate of open-access and open-source scientific software, Dr. Ladwig has developed various tools for process-based lake modeling to increase the accessibility of models for novice and experienced users. His current work investigates the physical-biogeochemical interactions that drive the long-term dynamics of hypolimnetic anoxia formation, and the phenology of metabolic processes driven by climate and land use changes. Dr. Ladwig is an active member of the Global Lake Ecological Observatory Network (GLEON), in which he moderates the lake modeling working group, and the Aquatic Ecosystem Modeling Network Junior (AEMON-J).
Postdoctoral Research Fellow, University of Wisconsin‐Madison, USA
Exploring lake metabolism phenology through modeling: How physics and ecology drive an emergent lake ecosystem property
The availability of dissolved oxygen in lakes governs ecological habitats and niches, redox reaction rates, and the decomposition of organic matter. Although proximal control over lake dissolved oxygen can be attributed to metabolism and physical processes, how those processes evolve over decades largely remains unexplored and there is much to be learned about the interactions of external drivers with internal processes that control metabolic patterns. As global change will affect in-lake metabolism significantly by decreasing oxygen solubility, enhancing respiration and primary production, and limiting vertical transport, robust approaches that combine observational data with process-based models are required to understand potential future changes in lake health.
In this talk, I will present three studies that applied different aquatic ecosystem modelling approaches to analyze long-term change of dissolved oxygen in lakes. By applying a vertical 1D lake model to quantify year-to-year dynamics of anoxia in an urban eutrophic lake, we found that anoxia variability is influenced primarily by physical processes, and less so by processes that influence organic matter decomposition. In the second study, a metabolism model framework was applied to multiple lakes in Wisconsin spanning a range of lake characteristics to investigate change in metabolism phenology. We found that landscape-related differences in metabolism between the forested lakes in the north and the urban lakes in the south are likely related to trophic states as well as hydrology. The third study showcases how hybrid modeling can improve aquatic ecosystem projections by combining process-based models with data-driven methods. By using high-frequency data directly in a modularized model framework, we can estimate challenging model parameters and processes while still getting physically valid results due to the process-based model framework.
Short bio:
Robert Ladwig is a physical limnologist and currently a Postdoctoral Research Fellow at the Center for Limnology at the University of Wisconsin-Madison. Dr. Ladwig received his Ph.D. jointly between the Leibniz-Institute of Freshwater Ecology and Inland Fisheries and the Chair of Water Resources Management and Modeling of Hydrosystems at the Technical University of Berlin. As a Visiting Researcher at Saitama University in Japan, he worked on improving mitigation strategies to prevent the formation of harmful algal blooms in reservoirs. His work explores linkages between physical and biogeochemical processes, and the influence on aquatic ecosystem's biology and ecosystem function through the use of cutting-edge data-intensive and computationally demanding techniques. As an advocate of open-access and open-source scientific software, Dr. Ladwig has developed various tools for process-based lake modeling to increase the accessibility of models for novice and experienced users. His current work investigates the physical-biogeochemical interactions that drive the long-term dynamics of hypolimnetic anoxia formation, and the phenology of metabolic processes driven by climate and land use changes. Dr. Ladwig is an active member of the Global Lake Ecological Observatory Network (GLEON), in which he moderates the lake modeling working group, and the Aquatic Ecosystem Modeling Network Junior (AEMON-J).
Practical information
- General public
- Invitation required
- This event is internal
Organizer
- ENAC
Contact
- Victoria Sanjuan