• Danum valley site, Malaysia
  •  Bintulu site, Malaysia
  • Kajikawa site, Niigata, Japan
  • Sakaerat site,Thailand

1. Background

Atmospheric deposition of sulfur compounds may gradually decrease according to the recent emission inventories in East Asia (e.g. Lu et al. 2010). However, the sulfur deposition level is still high and cumulative load of sulfur is quite large in the EANET(Acid Deposition Monitoring Network in East Asia) region. Since sulfur deposited on ecosystems may be retained in soil and/or cycled in the soil-plant system, manifestation of its effect may be delayed. In fact, in US and Europe, it was reported that sulfur accumulated in the past has been leaching to streams in forest area recently (e.g. Mitchell and Likens 2011). Moreover, several rivers/lakes for monitoring on inland aquatic environment in the EANET countries showed pH-declining trend with SO42−-increasing trend (EANET 2011). Effect of sulfur deposition on terrestrial ecosystems is one of the important issues to be investigated in the EANET region.

2. Project outline

Scientists from the Network Center (NC) and the EANET countries have been promoting the catchment-scale analysis in different types of forests, namely in Kajikawa site, Niigata, Japan, in Sakaerat site, Nakhon Ratchasima, Thailand and in Danum Valley site, Sabah, Malaysia. Taking account of the background above, the research team made efforts to obtain a new grant to study sulfur dynamics in the forest catchments. Finally, the team has successfully obtained the research grant from the international research fund, Asia Pacific Network on Global Change Research (APN). Based on the existing catchment project, sulfur dynamics in the forest ecosystems will be investigated.

3. Objectives

  • To clarify sulphur dynamics (flux, retention time, speciation of accumulated sulphur compounds, etc.) in ecosystems of the East Asian forests
  • To discuss combined effects of sulphur and nitrogen on acidification and eutrophication of the East Asian forests.

    4. Acknowledgments

    The project above was supported by the Asia Pacific Network for Global Change Research (APN) (ARCP2012-18NMY-Sase). Part of the surveys in Sakaerat site and Bintulu site was financially supported by KAKENHI (Grants-in-Aid for Scientific Research ) (20120012) from MEXT (Ministry of Education,Culture,Sports,Science & Technology in Japan), Japan and Mitsubishi Corporation, Japan, respectively.

    5. References

  • EANET 2011. The Second Periodic Report on State of Acid Deposition in East Asia. Network Center for EANET.
  • Lu et al. 2011. Sulfur dioxide and primary carbonaceous aerosol emissions in China and India, 1996–2010. Atmos. Chem. Phys., 11, 9839–9864.
  • Mitchell, M, Likens, G. 2011. Watershed sulfur biogeochemistry: Shift from atmospheric deposition dominance to climatic regulation.