Distribution characteristics of dissolved organic carbon in annular wetlandsoil-water solutions through soil profiles in the Sanjiang Plain, Northeast China
XI Min , LU Xian-guo , LI Yue , KONG Fan-long
DOI:
Received November 23, 2006,Revised February 04, 2007, Accepted , Available online
Volume 19,2007,Pages 1074-1078
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Overwhelming evidence reveals that concentrations of dissolved organic carbon (DOC) have increased in streams which brings
negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove
to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was
focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing
wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater
solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0–10 cm
and 10–20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland (R2<\sup> = 0.3122
and R2<\sup> = 0.443). The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in
annular wetland soil-water solutions. The concentrations of total organic carbon (TOC), total carbon (TC) and Fe(II), DOC mobility
and continuous vertical and lateral flow a ected the distribution variations of DOC in soil-water solutions. The correlation coe cients
between DOC concentrations and TOC, TC and Fe(II) were 0.974, 0.813 and 0.753 respectively. These distribution characteristics
suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed
depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source
of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the
spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the
Sanjiang Plain.
