Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Oral

A (Atmospheric and Hydrospheric Sciences) » A-CG Complex & General

[A-CG40] Material Circulations in Land Ecosystems

Thu. May 24, 2018 10:45 AM - 12:15 PM 106 (1F International Conference Hall, Makuhari Messe)

convener:Tomomichi Kato(Research Faculty of Agriculture, Hokkaido University), Takashi Hirano(Research Faculty of Agriculture, Hokkaido University), Hisashi Sato(海洋研究開発機構 地球表層物質循環研究分野, 共同), Ryuichi Hirata(National Institute for Environmental Studies), Chairperson:Sato Hisashi(JAMSTEC)

11:30 AM - 11:45 AM

[ACG40-04] The influence of long-term soil warming on heterotrophic respiration in an evergreen broad-leaved forest in Hiroshima

*Munemasa Teramoto1, Naishen Liang1, Toshiaki Kondo2, Jiye Zeng1, Kaneyuki Nakane3 (1.National Institute for Environmental Studies, 2.Graduate School for International Development and Cooperation, Hiroshima University, 3.Hiroshima University)

Keywords:Global warming, Heterotrophic respiration, Chamber , Evergreen broad-leaved forest, Soil organic carbon , Asian monsoon

Soil respiration is the second largest carbon flux in terrestrial ecosystems, and consists of root respiration and heterotrophic respiration (Rh). Global Rh is estimated to be 51–57 GtC yr-1, more than the half of global soil respiration. It is commonly observed that Rh exponentially increases with rising temperature. Therefore, only a tiny rise of temperature will result in remarkable increase of Rh. That point implies that increased global Rh under warmer environment might further accelerate global warming (positive feedback). However, long-term soil warming experiment that verify the response of Rh to global warming is totally limited in Asian monsoon forests where exhibit high productivity. Examining the response of Asian monsoon forest soil to global warming is thought to be critical for precise estimation for future climate change.

To examine the long-term influence of soil warming on Rh in an Asian monsoon forest, we set multi-channel automated chamber and soil warming systems in an evergreen broad-leaved forest in western Japan, Higashi Hiroshima in September 2007. We prepared 10 trenched chambers (90 cm × 90 cm × 50 cm) to continuously measure Rh. Half of those trenched chambers were artificially warmed by infrared heaters 1.6 m above the soil surface (+2.5ºC), and influence of soil warming on Rh was examined by comparing Rh and warmed Rh for 10 years.

Soil moisture and Rh were strongly related during summer period from July to September. Few precipitation and low soil moisture level in summer period caused to decrease Rh, and the decrease resulted in the decline of annual temperature sensitivity of Rh (Q10). Those results suggested that precipitation and soil moisture during summer period is one of the important control factor for long-term response of Rh to warmer environment.