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Atmospheric deposition versus rock weathering in the control of streamwater chemistry in a tropical rain-forest catchment in Malaysian Borneo

Research output: Contribution to Journal/MagazineJournal articlepeer-review

  • N. Yamashita
  • H. Sase
  • R. Kobayashi
  • Leong Kok Peng
  • Jamal Mohd Hanapi
  • S. Uchiyama
  • S. Urban
  • Toh Ying-Ying
  • Maznorizan Muhamad
  • Jikos Gidiman
  • Nick A. Chappell
<mark>Journal publication date</mark>09/2014
<mark>Journal</mark>Journal of Tropical Ecology
Issue number5
Number of pages12
Pages (from-to)481-492
Publication StatusPublished
Early online date3/07/14
<mark>Original language</mark>English


Uncertainty about the H+ buffering capacity in tropical rain forest limits our ability to predict the future effect of anthropogenic deposition on the streamwater chemistry. Export ofmajor ions to the stream and the ion-fluxes via rainfall, throughfall, litter-leachate and soil-water pathways were observed to examine the source of streamwater nutrients in a small catchment in Sabah, Malaysia. The streamwater and the ion-fluxes were measured for 3.75 and 2 y, respectively, by collecting water twice a month and setting ion-exchange-resin columns. Streamwater pH ranged from 6.5 to 7.6 and was not sensitive to water discharge controlling base cations. The NO3--N, Ca2+ and Mg2+ fluxes were low in atmospheric depositions (0.6, 0.5 and 0.3 kg ha−1 y−1, respectively) andmarkedly increased in litter layer. The NO3 flux decreased drastically from subsoil (70 kg ha−1 y−1) to the stream (1.4 kg ha−1 y−1) whereas the Ca2+ and Mg2+ fluxes were not different between subsoil (38 and 18 kg ha−1 y−1) and stream (30 and 15 kg ha−1 y−1). Neutral pH in tropical streams was mainly due to the base cation leaching with deep chemical weathering in deeper strata, and a rapid decrease in NO3 leaching from the subsoil to the stream.

Bibliographic note

http://journals.cambridge.org/action/displayJournal?jid=TRO The final, definitive version of this article has been published in the Journal, Journal of Tropical Ecology 30 (5), pp 481-492 2014, © 2014 Cambridge University Press.