Haojia (Abby) Ren has contributed greatly to the new interdisciplinary area that we might call paleobiogeochemistry. Ren’s major contribution in this area has been her development and application of the nitrogen isotopic analysis of the organic matter that is bound within the shells of foraminifera (foraminifera-bound δ15N). Ren developed the methods for this measurement, on which she is now the international authority. She has spearheaded the effort to begin the ground-truthing of this new proxy, and she has a provided a foundational understanding. For example, Ren and her colleagues have shown that the internal N cycling of dinoflagellate symbiont-bearing foraminiferal species affects their δ15N in a predictable way.
With foraminifera-bound δ15N, Ren has made major discoveries regarding the N cycle in the past ocean. Focusing first on the low-nutrient tropical and subtropical ocean, Ren found that the rate of N2 fixation, the dominant process that brings new biologically available N into the ocean, was reduced during the last ice age, contrary to a popular hypothesis that elevated dust delivery to the ice age ocean would have broadly accelerated the process. Instead, Ren and her colleagues have found that N2 fixation varied over glacial cycles in a way that is consistent with the process acting as a negative feedback against changes in the size of the ocean N reservoir.
Ren has also made major discoveries regarding the nutrient conditions of the high-latitude oceans and the equatorial Pacific. In the subarctic North Pacific, Ren’s measurements indicate an ice age reduction in the circulation-driven nitrate supply, suggesting a remarkable similarity with the Antarctic Ocean during the ice ages. Ren collaborated with Dr. Alfredo Martinez Garcia to reconstruct nitrate consumption in the subantarctic ocean over the last glacial cycle. The resulting data indicate iron fertilization in this region during dust-rich cold periods, contributing to the lowering of atmospheric CO2 during ice ages. In the equatorial Pacific, Ren worked with Kassandra Costa, finding that dust-borne iron fertilization was not important there during the last ice age, consistent with the limited direct role of dust in supplying iron to the region.
Ren’s research group at National Taiwan University is rapidly expanding into new areas. One recent result is a coral δ15N-based reconstruction of anthropogenic N deposition in the South China Sea.
Abby Ren is a stunningly strong scientist and a remarkable individual. She is all at once brilliant, determined, courageous, opinionated, humble, generous, and supportive. Her selection as the first recipient of the Nanne Weber Early Career Award is richly deserved.
—Daniel M. Sigman, Princeton University, Princeton, N.J.
I am truly honored and humbled to be the first recipient of the Nanne Weber Early Career Award, and I thank the Paleoceanography section for this recognition.
I am particularly indebted to my mentor Danny Sigman, who took me on this magical exploratory journey. It was Danny’s idea to measure nitrogen isotopes on the trace amount of organic materials embedded within the calcite shells of the forams, and I started as a fearless and ignorant soldier. Years have passed since we generated the first data point, and I am still nowhere close to matching Danny’s profound and tireless intellect, but I hope that I have acquired the passion, the skills, and some degree of creativity from him.
I had a great fortune to work alongside Bob Anderson at Lamont-Doherty Earth Observatory. His passion and determination behind his objective and fair scientific view, as well as his generosity and kindness, attract talents around him toward common goals. I hope that I have gotten some of his wisdom and nobleness to work among scientists with different views.
When I took a life-changing decision to follow my family to Taiwan, George Wong and his group in Academia Sinica welcomed me with their big hearts. They have supported me through the most difficult transition for my career and family.
I thank all of my collaborators for the inspirations, especially Tony Wang, Alfredo Martinez Garcia, Anja Studer, Kassandra Costa, Tom DeCarlo, Anne Cohen, Howie Spero, and Gerald Haug. I also cannot imagine my science without all the great technicians: Sergey Oleynik, Julien Foriel, Alexa Weigand, Yi Wang, and Yi-Chi Chen. I thank all of my colleagues, team members in Taiwan, and of course my dearest family for all the support and love. Finally, to my past, present, and future students: “Good science is science that inspires.” —Nanne Weber.
—Haojia Abby Ren, National Taiwan University, Taipei