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Erik Jeppesen

Response of chromophoric dissolved organic matter dynamics to tidal oscillations and anthropogenic disturbances in a large subtropical estuary

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  • Yongqiang Zhou, Sino Danish Ctr Educ & Res SDC, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Chinese Academy of Sciences, Sino-Danish Centre for Education and Research, UCAS, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Sinodanish Ctr Educ & Res SDC, Chinese Acad Sci, Nanjing Inst Geog & Limnol, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm, Denmark
  • Yuan Li, Taihu Lake Laboratory EcosystemResearch Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
  • Xiaolong Yao, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Chinese Academy of Sciences, Univ Chinese Acad Sci, University of Chinese Academy of Sciences, CAS, Chinese Academy of Sciences, Coll Resources & Environm
  • ,
  • Wenhao Ding, Taihu Lake Laboratory EcosystemResearch Station, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
  • Yibo Zhang, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Chinese Academy of Sciences
  • ,
  • Erik Jeppesen
  • Yunlin Zhang, Chinese Acad Sci, Nanjing Inst Geog & Limnol, Taihu Lab Lake Ecosyst Res, State Key Lab Lake Sci & Environm
  • ,
  • David C. Podgorski, Pontchartrain Institute for Environmental Sciences, Department of Chemistry, University of New Orleans, New Orleans, Univ New Orleans, University of New Orleans, University of Louisiana System, Dept Chem, Pontchartrain Inst Environm Sci, United States
  • Chunmei Chen, Zhejiang University o Water Resources and Electric Power, Hangzhou 310018, China, China
  • Yi Ding, Zhejiang Hydrology Bureau, Hangzhou 310009, China, China
  • Huawu Wu
  • ,
  • Robert G.M. Spencer, Woods Hole Research Center, Florida State Univ, Florida State University, Florida State University System, Dept Oceanog, Florida State Univ, Florida State University, Florida State University System, Dept Earth Ocean & Atmospher Sci, Denmark

Estuaries support the livelihood of ~75% of the world's population and maintain high primary production in coastal waters, which are often subjected to strong tides and anthropogenic disturbances. There is a paucity of information on how the optical composition and bioavailability of chromophoric dissolved organic matter (CDOM) are influenced by tidal oscillations in estuaries with highly urbanized surrounding areas. We examined the semi-diurnal Qiantang Bore, one of the Earth's three most predominant tide bores, and found that dissolved organic carbon (DOC), CDOM absorption a(254) and terrestrial humic-like C1, tryptophan-like C2 and C5, fulvic-like C3, and microbial humic-like C4 decreased markedly with increasing salinity. This suggests that physical mixing of riverine freshwater and saltwater can shape the optical composition of CDOM in the estuary. This was supported by the semi-diurnally and hourly observations at Zhijiang (salinity ~0.1‰ upstream of the estuary) that DOC, bioavailable DOC (BDOC), C1–C2, and C4–C5 increased markedly with decreasing tidal level, while DOC and C1–C5 increased notably with increasing salinity. We further found δ 18 O was enriched with increasing tidal level, while tryptophan-like C2 and C5, and fulvic-like C3 decreased significantly with increasing tidal level at Zhapu (salinity ~7‰ downstream of the estuary). Furthermore, DOC, BDOC, C1, and C4 decreased, while δ 18 O and C3 increased markedly with increasing salinity. Further evidences come from the notably lower mean first principal component (PC1) scores at Zhijiang and Zhapu, both positively associated with anthropogenic tryptophan-like inputs, were observed during ebb than during flood tides, and PC1 at Zhijiang increased notably with increasing salinity. We conclude that anthropogenic inputs contributed primarily to the CDOM pool in the estuary and are mediated by the physical mixing of riverine freshwater and seawater, and ebb tides are often associated with enhanced anthropogenic CDOM with relatively high bioavailability.

Original languageEnglish
JournalScience of the Total Environment
Volume662
Pages (from-to)769-778
Number of pages10
ISSN0048-9697
DOIs
Publication statusPublished - 2019

    Research areas

  • Chromophoric dissolved organic matter (CDOM), Parallel factor analysis (PARAFAC), Qiantang estuary, Tidal oscillations, Ultrahigh resolution mass spectrometry

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