Shun Hasegawa
Research Scientist
Biography
I have been assigned as the head of the Norwegian National Soil Carbon Monitoring programme at NIBIO since 2023. My role is to lead, develop and execute this very first soil carbon monitoring project in Norway.
I am a climate change biologist with broad interests in the impacts of human activities and associated climate/environmental changes on global biogeochemical processes. I completed PhD at Imperial College London in 2015 with a thesis entitled Investigation into the effects of elevated carbon dioxide and temperature on nutrient cycling and understorey vegetation in a Eucalyptus woodland. My previous work can be found here.
Previous employment:
- 2022-2023 Senior Research Engineer at Umeå University with a focus on the role of root carbon supply on oxidative decomposition in the boreal soil.
- 2018-2022 Postdoc at Swedish University of Agricultural Sciences with a focus on the long-term effects of nitrogen addition on organic matter accumulation in boreal forests.
- 2017-2018 Senior research technician at National Institute for Environmental Studies of Japan with a focus on meta-analysis on microbial immobilisation.
- 2015-2017 Postdoc at Hawkesbury Institute for the Environment, Western Sydney University with a focus on the effects of elevated CO2 and water availability on soil nutrient availability in relation to root exudates.a
Authors
Mingkai Jiang Belinda E. Medlyn David Wårlind Jürgen Knauer Katrin Fleischer Daniel S. Goll Stefan Olin Xiaojuan Yang Lin Yu Sönke Zaehle Haicheng Zhang He Lv Kristine Y. Crous Yolima Carrillo Catriona Macdonald Ian Anderson Matthias M. Boer Mark Farrell Andrew Gherlenda Laura Castañeda-Gómez Shun Hasegawa Klaus Jarosch Paul Milham Raúl Ochoa-Hueso Varsha Pathare Johanna Pihlblad Juan Piñeiro Nevado Jeff Powell Sally A. Power Peter Reich Markus Riegler David S. Ellsworth Benjamin SmithAbstract
The importance of phosphorus (P) in regulating ecosystem responses to climate change has fostered P-cycle implementation in land surface models, but their CO2 effects predictions have not been evaluated against measurements. Here, we perform a data-driven model evaluation where simulations of eight widely used P-enabled models were confronted with observations from a long-term free-air CO2 enrichment experiment in a mature, P-limited Eucalyptus forest. We show that most models predicted the correct sign and magnitude of the CO2 effect on ecosystem carbon (C) sequestration, but they generally overestimated the effects on plant C uptake and growth. We identify leaf-to-canopy scaling of photosynthesis, plant tissue stoichiometry, plant belowground C allocation, and the subsequent consequences for plant-microbial interaction as key areas in which models of ecosystem C-P interaction can be improved. Together, this data-model intercomparison reveals data-driven insights into the performance and functionality of P-enabled models and adds to the existing evidence that the global CO2-driven carbon sink is overestimated by models.
Authors
Mingkai Jiang Kristine Y. Crous Yolima Carrillo Catriona A. Macdonald Ian C. Anderson Matthias M. Boer Mark Farrell Andrew N. Gherlenda Laura Castañeda-Gómez Shun Hasegawa Klaus Jarosch Paul J. Milham Rául Ochoa-Hueso Varsha Pathare Johanna Pihlblad Juan Piñeiro Jeff R. Powell Sally A. Power Peter B. Reich Markus Riegler Sönke Zaehle Benjamin Smith Belinda E. Medlyn David S. EllsworthAbstract
The capacity for terrestrial ecosystems to sequester additional carbon (C) with rising CO2 concentrations depends on soil nutrient availability1,2. Previous evidence suggested that mature forests growing on phosphorus (P)-deprived soils had limited capacity to sequester extra biomass under elevated CO2 (refs. 3,4,5,6), but uncertainty about ecosystem P cycling and its CO2 response represents a crucial bottleneck for mechanistic prediction of the land C sink under climate change7. Here, by compiling the first comprehensive P budget for a P-limited mature forest exposed to elevated CO2, we show a high likelihood that P captured by soil microorganisms constrains ecosystem P recycling and availability for plant uptake. Trees used P efficiently, but microbial pre-emption of mineralized soil P seemed to limit the capacity of trees for increased P uptake and assimilation under elevated CO2 and, therefore, their capacity to sequester extra C. Plant strategies to stimulate microbial P cycling and plant P uptake, such as increasing rhizosphere C release to soil, will probably be necessary for P-limited forests to increase C capture into new biomass. Our results identify the key mechanisms by which P availability limits CO2 fertilization of tree growth and will guide the development of Earth system models to predict future long-term C storage.