Contributions of humic substances to the dissolved organic carbon pool in wetlands from different climates

Authors

Akira Watanabe, Graduate School of Bioagricultural Sciences, Nagoya UniversityFollow
Kunio Moroi, Graduate School of Bioagricultural Sciences, Nagoya University
Hiromu Sato, Graduate School of Bioagricultural Sciences, Nagoya University
Kiyoshi Tsutsuki, Obihiro University of Agriculture and Veterinary MedicineFollow
Nagamitsu Maie, Faculty of Environment and Veterinary Sciences, Kitasato UniversityFollow
Lulie Melling, Tropical Peat Research Laboratory Unit, Chief Minister’s Department, MalaysiaFollow
Rudolf Jaffe´, Southeast Environmental Research Center, Department of Chemistry and Biochemistry, Florida International University,Follow

Abstract

Wetlands are an important source of DOM. However, the quantity and quality of wetlands’ DOM from various climatic regions have not been studied comprehensively. The relationship between the concentrations of DOM (DOC), humic substances (HS) and non-humic substances (NHS) in wetland associated sloughs, streams and rivers, in cool temperate (Hokkaido, Japan), sub-tropical (Florida, USA), and tropical (Sarawak, Malaysia) regions was investigated. The DOC ranged from 1.0 to 15.6 mg C L⁻¹ in Hokkaido, 6.0–24.4 mg C L⁻¹ in Florida, and 18.9–75.3 mg C L⁻¹ in Sarawak, respectively. The relationship between DOC and HS concentrations for the whole sample set was regressed to a primary function with y-intercept of zero (P < 0.005) and a slope value of 0.841. A similar correlation was observed between DOC and NHS concentrations, with a smaller slope value of 0.159. However, the correlation coefficient of the latter was much larger when the data was regressed to a logarithmic curve. These observations suggest the presence of a general tendency that the increased DOC in the river waters was mainly due to the increased supply of HS from wetland soils, whereas the rate of the increase in the NHS supply has an upper limit which may be controlled by primary productivity.

Comments

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Watanabe, A., K. Moroi, H. Sato, K. Tsutsuki, N. Maie, L. Melling, R. Jaffe. 2012. Contributions of humic substances to the dissolved organic carbon pool in wetlands from different climates. Chemosphere 88(10): 1265-1268.