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Research in the Menge lab addresses fundamental questions in ecosystem ecology using theory, observations, experiments, and data synthesis. Although much of the focus is basic science, our work is highly relevant to pressing societal concerns such as global climate change and eutrophication because of the intimate connections between nutrients, plants, and greenhouse gases. The following themes characterize research in the Menge lab.
The theoretical foundation of ecosystem ecology lags behind other ecological disciplines, despite the wealth of benefits that theory can bring. For example, disease ecology theory has led to a basic understanding of disease dynamics that has helped eradicate harmful diseases. A main thrust of research in the Menge lab is to continue building the theoretical foundation of ecosystem ecology.
"Nothing in biology makes sense except in the light of evolution" (Dobzhansky). "Ecosystems are prototypical examples of complex adaptive systems, in which patterns at higher levels emerge from localized interactions and selection processes acting at lower levels" (Levin). These evolutionary perspectives are underappreciated in biogeochemistry, despite that prominent "bio" prefix. We use mathematical theory and data analysis to investigate how evolution affects questions in ecosystem ecology and biogeochemistry.
"Water, water everywhere, nor any drop to drink" (Coleridge). Sailors are surrounded by water, yet risk dying of thirst because seawater is undrinkable. Similarly, most plants are bathed in nitrogen, yet often suffer nitrogen deficiency because they cannot use dinitrogen gas. Nitrogen-fixing bacteria, and the plants with which they form symbioses, are in a unique position because they can use this inexhaustible resource. Because of this, they are involved in lots of interesting questions in ecosystem ecology and biogeochemistry. Also, "nodule" is really fun to say.
Nitrogen and phosphorus commonly limit plant growth and other ecosystem processes. Sometimes just one does, and sometimes both do, and the patterns of nutrient limitation are often counterintuitive. We use a combination of theory, experiments, observations, and data synthesis to try to address this broad topic.
Some ecosystems emit lots of nitrogen, either as nitrate (which pollutes waterways) or as gaseous nitrogen (which pollutes the air or contributes to global warming). In some places this "nitrogen richness" is driven by human activity, primarily via fossil fuel combustion or fertilizer application. In other places, such as tropical rainforests, it appears to be driven by natural nitrogen fixation, even though we think that fixing nitrogen in these conditions is more expensive than using soil nitrogen. Why does this happen? What are the consequences?
Ratios of different nutrients, such as carbon, nitrogen, and phosphorus, often display well-constrained patterns. These patterns themselves are interesting, as are the insights they give us into ecosystem processes.
"[Scale] is ... the fundamental conceptual problem in ecology, if not in all of science" (Levin). So it's big. Or ... small. Ecosystem and biogeochemical processes operate on vastly different scales of time, space, and level of organization, and patterns at one scale are often influenced by processes at other scales. Scale is a theme running through research in the Menge lab. For example, the development of ecosystem nutrient cycles occurs across a huge range of timescales, which we study empirically and theoretically.
Global models are our best tools for making quantitative predictions about global environmental issues such as climate change. Take a look at any IPCC report and you will see their importance. Although most general circulation models now include a carbon cycle, the representation of nitrogen and phosphorus is in its infancy, despite the importance of these nutrients for carbon fluxes and climate. The Menge lab is working with groups from NOAA's GFDL lab and Princeton to develop nutrient cycles in GFDL's state of the art Earth System Model.