Kraemer Benjamin M. PhD

Research

Lakes integrate changes occurring across the atmosphere, landscape, and watershed, making them sensitive indicators of global environmental change. Yet lakes exposed to similar pressures often respond very differently, because climate forcing interacts with lake physics, morphology, catchment processes, and ecological communities. My research therefore asks why lakes respond differently to environmental change and how those differences translate into consequences for ecosystem structure and function.

A central focus of my work is the physical environment of lakes. Warming, altered mixing, changing water levels, and extreme events can profoundly modify the conditions experienced by aquatic organisms, but physical change does not translate uniformly into ecological change. I investigate these links through research on lake temperature, stratification and thermal habitat, deoxygenation, phytoplankton and water quality, carbon cycling, biodiversity, and biological invasions. My work combines field observations, long-term monitoring, satellite remote sensing, large environmental datasets, and quantitative modelling, from individual lakes to the global scale.

At Innsbruck, I am particularly interested in Alpine and other mountain lakes, where environmental change is often especially rapid. Despite their value as sentinels of global change, it remains unclear which responses observed in individual mountain lakes reflect local conditions and which represent more general ecological mechanisms. By connecting detailed observations from mountain lakes with regional and global datasets, I aim to use these systems both to understand local ecosystem change and to test broader principles of how lakes respond to a rapidly changing world.

Research interests

• Global change aquatic ecology
• Climate-change impacts on lakes
• Lake temperature, stratification, mixing, and upwelling
• Dissolved oxygen and lake deoxygenation
• Water quality
• Carbon cycling and lake–climate interactions
• Biodiversity responses to environmental change
• Neobiota
• Remote sensing of inland waters
• Large-scale environmental data synthesis and modelling

Research approach

My research is built around international team science. Many of the questions I work on, particularly those concerning global environmental change, cannot be answered from a single lake, dataset, or discipline. I therefore collaborate with researchers across countries and institutions to bring together complementary observations, expertise, and analytical approaches.

These collaborations often integrate data collected at very different spatial and temporal scales, including in-situ measurements, vertical lake profiles, satellite observations, meteorological and catchment data, long-term monitoring records, and ecosystem and climate-model simulations. I am especially interested in moving between scales: using intensive studies of individual lakes to identify mechanisms, coordinated networks of lakes to test their generality, and international data synthesis and modelling efforts to investigate how lake ecosystems may change in the future.

A major part of this work is my involvement in the Global Lake Ecological Observatory Network (GLEON), an international network that brings together researchers, students, educators, and practitioners to advance collaborative lake science across geographic and disciplinary boundaries. I currently lead GLEON’s Synthesis Working Group, which supports projects that connect ideas, data, and expertise across the network’s thematic working groups, fosters cross-group collaborations, and strengthens links with other research networks. Learn more about GLEON and its working groups on the GLEON website.

Teaching and student supervision

I teach and supervise students in freshwater ecology, limnology, global change ecology and quantitative environmental science. My teaching emphasizes combining ecological concepts with field observations, data analysis, experiments, modelling and scientific communication.

Previous teaching included Aquatic Ecology, Fish Ecology, Quantitative Analysis with R, Conservation Biology, and workshops on scientific comics, writing, and communication.

I welcome student projects involving mountain lakes, lake monitoring, remote sensing, global environmental datasets, ecological modelling and freshwater responses to global change.

Background

Before joining the University of Innsbruck, I worked at the University of Freiburg, the University of Konstanz, the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin, and the University of Wisconsin–Madison. I received my PhD in Freshwater and Marine Science from the University of Wisconsin–Madison, where I studied global patterns in lake ecosystem responses to climate change.

selected Publications

• Kraemer, B.M. et al. (2023). An abundant future for quagga mussels in deep European lakes. Environmental Research Letters.
• Kraemer, B.M., Kakouei, K., Munteanu, C., Thayne, M.W. & Adrian, R. (2022). Worldwide moderate-resolution mapping of lake surface chl-a reveals variable responses to global change (1997–2020). PLOS Water.
• Kraemer, B.M. et al. (2021). Climate change drives widespread shifts in lake thermal habitat. Nature Climate Change.
• Woolway, R.I., Kraemer, B.M., Lenters, J.D., Merchant, C.J., O’Reilly, C.M. & Sharma, S. (2020). Global lake responses to climate change. Nature Reviews Earth & Environment.
• Kraemer, B.M. et al. (2017). Global patterns in lake ecosystem responses to warming based on the temperature dependence of metabolism. Global Change Biology.

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