What’s in a Wetland’s Breath? Composition and Controls of Greenhouse Gas Emissions from a Restored Wetland in the Sacramento Delta
I first became interested in ecology, and particularly in trace gas bio-geochemistry, during an undergraduate exchange from Stirling University (UK) to UC Berkeley about 8 years ago. In their class on ecosystem ecology, Professors Whendee Silver & Dennis Baldocchi talked about the invisible exchanges of matter and energy constantly taking place between soil microbes, plants, and the atmosphere, and the huge consequence this ‘breathing of the biosphere’ had on global climate. Placing anthropogenic effects in the context of a global ecology opened up a new and exciting way to view the grandeur and interconnectedness of the Earth system, and possibly develop climate change solutions.
I’m grateful, all these years later, that I got to work under guidance of the same people who originally inspired me. My dissertation committee members, Professor Silver and Professor Baldocchi – along with Professor John Coates of PMB – gave me everything I needed to study gas exchange in the Sacramento Delta, CA, a region that exemplifies the complexity of coupled human and natural ecosystems. Together we explored the fundamental thermodynamics of microbial redox reactions that control soil gas production and consumption. I got to dig deep into the literature on the physics of life, taking me back to early and prescient work by Schrödinger and Vernadksy, and I got to think about a cosmic, quantum ecology driven by fluxes of photons, protons, and electrons, and all cycled and recycled through life on Earth via the breathing of the biosphere.
Running parallel to this trip into theory and experimental work, my Delta wetland fieldwork gave me a chance to design new chambers, test out new gas extraction techniques, and look for very rare (parts-per-trillion) radiocarbon isotopes in both methane and carbon dioxide. These approaches showed us the dynamic seasonal and spatial patterns of wetland greenhouse gas exchange, and let us probe the links between plants, soil, and microbes, in the uptake and release of wetland carbon, bringing me full circle with new insights into the composition and controls of the biosphere’s breath.
In addition to my dissertation committee I’d like to thank the Delta Stewardship Council, the National Science Foundation, and Lawrence Livermore National Laboratory for funding my graduate research, and my peers and colleagues in ESPM at UC Berkeley for all the practical and moral support along the way.