Research interests
Broadly, I am interested in Earth System Science.
The goal of my research is to understand Earth System processes, with an emphasis on the interaction and inter-relation between life and the physical planet (Fig 1).
For my PhD I investigated how life has shaped Earth’s surface environments, from the deep past to historical time, using cosmogenic and novel stable isotopes and shallow subsurface geophysics, sedimentology, and hydrogeology.
Human cultural practices and soil erosion: By applying a paired cosmogenic isotope toolkit to well-characterized, ancient fluvial sediments from the Channel Islands of California, I quantified soil erosion rates from pre-human arrival through archeological and historical time. Despite transforming the environment through use of fire, I found that hunter-gatherers did not increase erosion rates, while later grazing elevated erosion rates 5-fold. These results clarify drivers of soil loss, inform sustainable management, and pave the way for addressing heated debates surrounding early human land use practices and ecological collapse on other islands (Fig. 1– yellow arrows; Fig. 2; ready for submission to Science; draft available upon request).
Human-induced fires and changes to groundwater: Using water isotope analysis, saturated hydraulic conductivity measurements, and time-lapse electrical resistivity tomography (ERT) across multiple catchments in the 2025 Palisades Fire burn area, I found that post-fire hydrology is best explained by a three-phase model: a baseline pre-fire phase, an overland-flow-dominated phase, and a later infiltration-dominated phase in which rill incision creates preferential infiltration pathways through the hydrophobic layer. These findings reconcile previous explanations of post-fire hydrology, explain the development of surface erosion features after fires, and point to rilling as an important post-fire feature that acts as a conduit for subsurface moisture infiltration (Fig. 1– red arrows; Fig. 3; ready for submission to AGU Advances; draft available upon request).
Coevolution of plants and the carbon cycle: By reconstructing the Late Paleozoic (420–300 Ma) lithium isotope composition of seawater from globally distributed, well-preserved brachiopods, I found that the lithium isotope record covaries with the radiogenic strontium isotope ratios, carbonate carbon isotope ratios, organic carbon burial, and atmospheric pCO2. I found no evidence of a unidirectional, stepwise increase in silicate weathering intensity associated with the spread of the earliest forests in the Devonian Period—the prevailing paradigm in this field. Instead, I attribute observed periodicity to phases of mountain building, changes in low-temperature seafloor alteration, or the phased evolution of plant lineages with distinct rooting depths and reproductive strategies (Fig. 1– green arrows; Fig. 4; in-review at EPSL).
Late Miocene paleoenvironments: Multiproxy analysis of fossil soils in the Río Iruya Canyon of NW Argentina revealed that vegetation alternated between periods of increased gymnosperm and angiosperm cover. I found no relationship between C4 vegetation and fire activity, owing to the scarcity of C4 vegetation (Fig 1– blue arrows; in-minor revisions Paleo3).