The theoretical and empirical challenges of Biogeochemical Ecology include: making biogeochemical maps scalable; translating elemental chemistry into ecological niches; building a science that predicts how the abiotic forms a template for the biotic.
Twenty-five chemical elements form the recipe for virtually all life on earth; shortfall in any impedes performance and fitness. Gradients of biogeochemistry, combined with those of temperature and precipitation, must therefore create a map of the performance of individuals, the fitness of populations, the structure and function of ecological communities, and the efficacy of ecosystem services. Global Change, in turn, manifests as a massive, continent-scale redistribution and manipulation of temperature, precipitation, and biogeochemistry. My lab’s work focuses on building an empirical and theoretical framework for understanding how Biogeochemical Ecology allows us to predict the consequences of Global Change. This approach provides three basic, interrelated opportunities for transformative science.
- Collecting and scaling maps of biogeochemistry according to ecological process. NOAA’s maps of aerosol deposition, and USGS soil maps reveal how natural and anthropogenic drivers rearrange elemental availability on a continental scale that underlie patterns of eutrophication, carbon cycling, and acidification. Finer scale soil studies on the 25 and 50 ha study plots of the Center for Tropical Forest Science reveal the niche structuring of tree communities and their effects on soil biodiversity. Fertilizing still smaller plots from 1600 to 0.25 m2 reveal how the microbes and invertebrates of the brown food web respond in ways that sum to shape decomposition. Our lab pioneered work at each scale, yet scalable maps that link these processes and populations do not yet exist; particularly down to the millimeters and microns relevant to key players like nematodes, fungi, and bacteria. Scalability is one way of recognizing a mature science.
- Building and testing a theory of biochemistry-based niches. Despite readily available technology, ecologists know more about the genomes of species, than the elemental composition of species. Yet the niches of organisms are profoundly shaped by their biochemistry: from their investments in P-rich ribosomes and metal-rich enzymes, to chemically distinctive amino acids, to the Ca and P-rich endoskeletons of vertebrates, to the leaky and temperature sensitive Na/K pumps that drive osmoregulation. Our lab has continues to explore the population and ecosystem consequences of two such biochemistry-based niches. One project explores the geographical consequences arising from the Na-poor diet confronting plant consumers. The second project explores the 20-year changes of invertebrate communities across North America as a function of their thermal tolerance, which is enhanced by loading up on P. A third project explores the trophic implications of bioaccumulation: that predators are more likely than their prey to achieve their quota of metals like Na, Cu, and Zn. All combine metabolic approaches that search for commonalities rooted in deep history of plants and animals, but with a natural historian’s eye for detail. When combined with scalable maps of biogeochemistry, they hold the potential for a deep understanding of the geographical ecology of abundance and ecosystem function.
- Fusing the three great classes of abiotic drivers into a useable theory predicting the synergy of multiple stressors. A hallmark of global change is the recombination of abiotic drivers to form new environments. Perhaps our greatest challenge is understanding how phenotypic plasticity, ecological filters, and natural selection shape populations and ecosystems particularly when we move beyond a singular focus on one driver like temperature or drought. In short, when do multiple stressors act like drug cocktails to hinder adaptive responses of organisms? We seek to understand the degree to which thermal and drought tolerance can be built from biochemical parts and how often-hidden patterns of malnutrition ramify to decrease resilience in populations and ecosystems.
To paraphrase GE Hutchinson, one of the great challenges for modern ecology is a deep understanding of how the Ecological Play is constrained by the Biogeochemical Theater.