The Ohio State University
Evolution, Ecology, and Organismal Biology
BART Enrollment Year: 2009
E-mail: kcalinge at umich.edu, calinger.2 at osu.edu
Biospheric Mentor: Dr. Peter Curtis, The Ohio State University
Atmospheric Mentor: Dr. Gil Bohrer, The Ohio State University
Kellen attended West Virginia University, where she received her B.S. in Biology. While at WVU, Kellen worked in Dr. Richard Thomas’ climate change lab. Her research, done in conjunction with the Duke Free Air CO2 Enrichment (FACE) project, focused on evaluating the progressive nitrogen limitation hypothesis in sweetgum trees. This was accomplished through examining foliar nitrogen partitioning in two canopy positions of sweetgum trees grown in elevated and ambient atmospheric CO2 and soil nitrogen levels.
Kellen is a PhD student in Evolution, Ecology, and Organismal Biology in Dr. Peter Curtis’ lab. Her research, completed at the University of Michigan Biological Station through the BART IGERT Program, examines the link between climatic and phenological events with emphasis on the role of climate change driven increases in growing season length and subsequent changes in net carbon storage. Further, through the Forest Accelerated Succession Experiment (FASET), Kellen’s research evaluates the impacts of species shifts and structural changes on key phenological events, and in turn, effects on carbon and nitrogen cycling and forest productivity.
Large-scale phenological shifts, or timing of key life events, have been observed across many ecosystems and are consistent with changes expected with climate change. With annual temperature increases of roughly 0.2oC, advancement in the timing of budburst and flowering have been widely observed. Earlier budburst and therefore longer growing seasons may have significant implications for carbon storage. Previous research has shown that increases of only one day in growing season have significantly increased forest net ecosystem productivity (NEP). However, the relationship between earlier budburst and NEP is not well established. Kellen’s research will examine the connection between phenological events at the species levels and phenological timing at the stand scale.
In contrast with the more evident relationship among increased temperature, earlier onset of budburst, and increased NEP, the connections between phenology and local, boundary-layer meteorology are much less understood. Leaf-out has been correlated with a wide variety of meteorological components including temperature, vapor pressure, and relative humidity. Kellen’s research will use precise phenological and meteorological observations to develop climate-biosphere models and determine the effects of phenological shifts on the climate-biosphere linkage so these findings can be incorporated into climate models.
Changes in timing of autumnal senescence have also been widely observed, although changes are more variable between ecosystems and more poorly understood than budburst events. Delayed leaf abscission may cause incomplete resorbtion of nutrients to storage organs as well as less N