The focus of my research is the cycling of carbon and nitrogen in the terrestrial biosphere. I am particularly interested in understanding how climate change and alterations in land use and management as well as in the frequencies of disturbances (i.e. drought, fire) affect the allocation and residence time of carbon and nitrogen in soils and perennial plants. And, how changes in terrestrial ecosystems feed back to the climate system, e.g. by constraining future levels of greenhouse gases in the atmosphere.

During the last two decades, it has become clear that microbes are present in practically all corners of the world - from the hot springs of Yellowstone to the deep subsurface of the ocean. DNA methods have uncovered a hitherto unknown biodiversity and conservative estimates predicts that microorganisms constitute more than 50% of the total biomass on Earth. Due to their diversity and abundance, microbes are significant contributors to most nutrient cycles in the global ecosystem and play a key role in climate regulation.

Plants and soils provide many services for society, such as the provision of food, water and materials; the regulation of atmospheric composition, hydrology, and water quality; and cultural and aesthetic services. In urban ecosystems where landscapes are intensively managed, there are also potential environmental and economic costs of creating and maintaining different soil and vegetation types. However, the environmental benefits and costs of urban landscapes have seldom been directly measured. We use a variety of methods to measure urban plant and soil processes and translate these processes into ecosystem services and disservices of interest to urban residents, managers, and policy-makers.

We seek to improve our understanding of global change in terrestrial ecosystems. We use remote sensing data, atmospheric trace gas observations, field measurements, and models in new ways to study feedbacks between terrestrial ecosystems and climate.

Trumbore uses stable and radioisotopes (especially 14C) to study how the Earth's natural exchanges of carbon among ocean, land and atmosphere are altered by human activity.She is a founding member of the Earth System Science Department at UC Irvine, and a co-director of the WM Keck Carbon Cycle Accelerator Mass Spectrometry Facility at UC Irvine.