Isotope Constraints on the Sources of Particulate Organic Carbon in a Subtropical Deep Reservoir

Li Wei Zheng, Dawei Li, Xiaodong Ding, Tsung Yu Lee, Zhenzhen Zheng, Fuh Kwo Shiah, Xufeng Zheng, Ting Chang Hsu, Jr Chuan Huang, Shuh Ji Kao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Reservoirs are active sites in the terrestrial environment in terms of carbon transformation and storage. Continuous reservoir construction reinforces the importance of such artificial storage; however, knowledge pertaining to the sources, cycling, and preservation of autochthonous/allochthonous particulate organic carbon (POC) in reservoirs remains incomplete. We monitored the flux and carbon isotope composition of sinking particles in a subtropical deep reservoir, and the results were compared with the isotopic signatures of potential POC sources (soil) and the sedimentary sink. We found that the typhoon-induced POC flux was transported laterally at intermediate water depths within the reservoir and that it contributed more than 70% of the annual deposition. An isotope ternary mixing model showed that over 87% of the POC preserved in sediments was allochthonous. Although the autochthonous POC from primary production was preferentially degraded, the preserved autochthonous POC (42 ± 14 gC m−2 yr−1) was comparable to the observed carbon dioxide uptake (35 gC m−2 yr−1) by the reservoir, suggesting a high efficiency of carbon preservation in subtropical deep reservoirs.

Original languageEnglish
Article numbere2019JG005240
JournalJournal of Geophysical Research: Biogeosciences
Volume125
Issue number1
DOIs
Publication statusPublished - 2020 Jan 1

Keywords

  • carbon isotopes
  • particulate organic carbon
  • subtropical reservoir
  • Taiwan
  • typhoon

ASJC Scopus subject areas

  • Soil Science
  • Forestry
  • Water Science and Technology
  • Palaeontology
  • Atmospheric Science
  • Aquatic Science
  • Ecology

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