Jianghui Du is a most deserving recipient of the Harry Elderfield Award of the AGU Paleoceanography and Paleoclimatology section. Du’s Ph.D. work at the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University exemplifies Harry Elderfield’s style, rooted in impeccable laboratory analytical skill, in creative application of geochemistry to important outstanding paleoceanographic problems, and in thinking anew about fundamental processes to overturn standard interpretations. Beyond his individual scholarship, Du is noted for peer mentoring of other students, again reminiscent of Elderfield’s generous collaborative style. The paper honored here by Du et al., “Flushing of the deep Pacific Ocean and the deglacial rise of atmospheric CO2 concentrations” (Nature Geoscience, 2018), opens a new window into understanding past changes in the abyssal Pacific circulation recorded by authigenic neodymium isotopes in deep-sea sediments. Du shows that for this tracer, where water residence times are relatively short, as in the deep Atlantic, conservative mixing dominates. But where water residence times are longer, such as in the deep Pacific, nonconservation driven mostly from chemical interactions with the seafloor dominates. By including both terms in quantitative models, Du explains perplexing data, resolves conflicts in geochemical budgets, and infers large variations in the deep Pacific circulation rate during the transition from glacial to interglacial conditions. His work further reveals a potential mechanism for flushing carbon from the deep Pacific to the atmosphere at the end of the last ice age. New thinking raises new questions, and these fresh insights will motivate further work. Du’s willingness to buck convention and think anew about difficult problems is worthy of celebration. We expect to hear much more from Jianghui Du as he moves beyond graduate school to a postdoctoral position at ETH Zürich, and we congratulate him on this richly deserved award.
—Alan C. Mix and Brian A. Haley, Oregon State University, Corvallis
I thank Alan and Brian for their generous citation comments and the AGU Paleoceanography and Paleoclimatology Award Committee for selecting my work for the 2019 Harry Elderfield Outstanding Student Paper Award. I feel particularly honored to receive an award named after one of the founders of my chosen field, rare earth element ocean chemistry and paleoceanography. The complex interactions between the ocean, the solid Earth, and the atmosphere, and the imprint of climate change on these interactions, turn a fascinating chemical problem into one that is both practical and important. I had the good fortune of building on some beautiful paleoceanographic records from recent field programs in the northeastern Pacific Ocean during my Ph.D. I am excited to start a career in paleoceanography at a time of rapidly expanding knowledge in the biogeochemical cycles of trace elements and isotopes in the modern ocean and of development of novel analytical tools that open new avenues of research. As a student, I experienced the full trajectory in the “Elderfield proxy confidence curve” of optimism, pessimism, and realism. I am particularly grateful to the National Science Foundation and other funding agencies for supporting this work, and to a group of mentors and peers at Oregon State and elsewhere whose steady support got me through the inevitable rough patches to the point of insight. I can only hope to follow in Harry Elderfield’s footsteps as an innovator and mentor, bridging the expanding fields of process-based knowledge of geochemical systems and paleoceanographic applications that help us to understand and thrive in a changing world.
—Jianghui Du, ETH Zürich, Zürich, Switzerland