Julia Diaz

Julia Diaz is an Associate Professor at the Geosciences Research Division of Scripps Institution of Oceanography, UC San Diego. Her research focuses on Marine Microbiology, Phytoplankton Biology, and Biogeochemistry with emphasis on phosphorus cycling dynamics in marine ecosystems. She investigates microbial nutrient acquisition strategies, dissolved organic matter transformations, and the biogeochemical roles of polyphosphates and reactive oxygen species in marine systems.

Her work spans diverse marine environments including the California Current, North Pacific Ocean, and Amazon River Plume. Key research themes include phosphorus limitation adaptation in phytoplankton, microbial community responses to environmental stressors, and the intersection of microbial physiology with global biogeochemical cycles.

Recent studies highlight the discovery of widespread extracellular superoxide production in marine microbes and its physiological significance, as well as novel insights into polyphosphate dynamics influencing calcium phosphate mineral formation. Diaz has pioneered methods for quantifying natural inorganic polyphosphates and pioneered the use of synchrotron-based X-ray fluorescence spectromicroscopy to study elemental distributions in marine organisms at sub-micron scales.

Her collaborative research includes NSF-funded projects exploring polyphosphate roles in marine phosphorus cycles and calcium phosphate precipitation mechanisms. Diaz has published extensively on topics ranging from microbial biofilm Mn(II) oxidation to coral symbiosis bioprinting, demonstrating her interdisciplinary approach to ocean science challenges.

Key contributions include identifying atypical phosphatases driving phosphorus utilization in stressed phytoplankton, elucidating sulfur isotope fractionation coupling in Desulfovibrio vulgaris, and revealing the critical roles of polyphosphate in geologic phosphorus sequestration processes.