Estuarine morphometry governs optically active substances, Kd(PAR) and beam attenuation: assessments from a tropical ria and a temperate coastal plain estuary

L. C. Lund-Hansen, J. M. Nielsen, J. Blüthgen, Doan Nhu Hai, Morten Holtegaard Nielsen, Nguyen Ngoc Lam

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Data on optical properties such as diffuse attenuation coefficient Kd(PAR), beam attenuation coefficient (cp) and the optically active constituents (OACs) CDOM, Chl-a and suspended particulate matter were obtained in a Danish temperate coastal plain estuary (56°N) and a Vietnamese tropical ria (12°N) at high discharges. The major difference was the spatial distribution of the optical properties against distance, best described by significant power functions in the ria, compared to significant linear functions in the coastal plain. It was hypothesized that estuarine morphometry could explain this spatial distribution. Partition and multiple regression analyses showed that Chl-a governed Kd(PAR) and beam attenuation coefficient in both estuaries. Significant, high correlations were obtained by multiple regression analyses in the estimation of Kd(PAR) and beam attenuation coefficients in the two estuaries using OACs as input parameters. It is concluded that there are no large differences in OAC concentrations between the two estuaries. The spatial distributions of OACs and optical properties were significantly different and governed by the estuary morphometry, i.e. a power distribution in the tropical ria and a linear function in the temperate coastal plain estuary, and applicable to similar estuary types.

Original languageEnglish
JournalHydrobiologia
Volume711
Issue number1
Pages (from-to)19-30
ISSN0018-8158
DOIs
Publication statusPublished - 2013

Keywords

  • Kd(PAR)
  • Beam attenuation coefficient
  • OACs
  • Temperate coastal plain estuary
  • Tropical ria
  • Denmark
  • Vietnam

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