論文

査読有り 筆頭著者 責任著者
2014年8月

Dissolved organic matter dynamics in the oligo/meso-haline zone of wetland-influenced coastal rivers

JOURNAL OF SEA RESEARCH
  • Nagamitsu Maie
  • ,
  • Satoshi Sekiguchi
  • ,
  • Akira Watanabe
  • ,
  • Kiyoshi Tsutsuki
  • ,
  • Youhei Yamashita
  • ,
  • Lulie Melling
  • ,
  • Kaelin M. Cawley
  • ,
  • Eikichi Shima
  • ,
  • Rudolf Jaffe

91
開始ページ
58
終了ページ
69
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.seares.2014.02.016
出版者・発行元
ELSEVIER SCIENCE BV

Wetlands are key components in the global carbon cycle and export significant amounts of terrestrial carbon to the coastal oceans in the form of dissolved organic carbon (DOC). Conservative behavior along the salinity gradient of DOC and chromophoric dissolved organic matter (CDOM) has often been observed in estuaries from their freshwater end-member (salinity = 0) to the ocean (salinity = 35). While the oligo/meso-haline (salinity <10) tidal zone of upper estuaries has been suggested to be more complex and locally influenced by geomorphological and hydrological features, the environmental dynamics of dissolved organic matter (DOM) and the environmental drivers controlling its source, transport, and fate have scarcely been evaluated. Here, we investigated the distribution patterns of DOC and CDOM optical properties determined by UV absorbance at 254 nm (A(254)) and excitation emission matrix (EEM) fluorescence coupled with parallel factor analysis (PARAFAC) along the lower salinity range (salinity < 10) of the oligo/meso-haline zone for three distinct wetland-influenced rivers; namely the Bekanbeushi River, a cool-temperate river with estuarine lake in Hokkaido, Japan, the Harney River, a subtropical river with tidally-submerged mangrove fringe in Florida, USA, and the Judan River, a small, acidic, tropical rainforest river in Borneo, Malaysia. For the first two rivers, a clear decoupling between DOC and A(254) was observed, while these parameters showed similar conservative behavior for the third. Three distinct EEM-PARAFAC models established for each of the rivers provided similar spectroscopic characteristics except for some unique fluorescence features observed for the Judan River. The distribution patterns of PARAFAC components suggested that the inputs from plankton and/or submerged aquatic vegetation can be important in the Bekanbeushi River. Further, DOM photo-products formed in the estuarine lake were also found to be transported upstream. In the Harney River, whereas upriver-derived terrestrial humic-like components were mostly distributed conservatively, some of these components were also derived from mangrove inputs in the oligo/meso-haline zone. Interestingly, fluorescence intensities of some terrestrial humic-like components increased with salinity for the Judan River possibly due to changes in the dissociation state of acidic functional groups and/or increase in the fluorescence quantum yield along the salinity gradient The protein-like and microbial humic-like components were distributed differently between three wetland rivers, implying that interplay between loss to microbial degradation and inputs from diverse sources are different for the three wetland-influenced rivers. The results presented here indicate that upper estuarine oligo/meso-haline regions of coastal wetland rivers are highly dynamic with regard to the biogeochemical behavior of DOM. (C) 2014 Elsevier B.V. All rights reserved.

リンク情報
DOI
https://doi.org/10.1016/j.seares.2014.02.016
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000338824400005&DestApp=WOS_CPL
ID情報
  • DOI : 10.1016/j.seares.2014.02.016
  • ISSN : 1385-1101
  • eISSN : 1873-1414
  • Web of Science ID : WOS:000338824400005

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