Mixing behavior of chromophoric dissolved organic matter in the Pearl River Estuary in spring. (15th February 2018)

• Record Type: Journal Article
• Authors: Lei, Xia; Pan, Jiayi; Devlin, Adam T.
• Is Part Of: Continental shelf research. Volume 154(2018)
• Page Start: 46
• Page End: 54
• Publication Date: 2018-02-15
• Subjects: CDOM -- Pearl River Estuary -- Absorption -- Mixing behavior -- Horizontal transport -- Vertical mixing; Continental shelf -- Periodicals; Submarine geology -- Periodicals; 551.41
• DOI: 10.1016/j.csr.2018.01.004
• Languages: English
• ISSNs: 0278-4343

Abstract

Abstract: Mixing behavior of chromophoric dissolved organic matter (CDOM) in the Pearl River Estuary (PRE) and relevant hydrodynamic parameters such as horizontal transport and vertical mixing are identified and discussed based on a set of sampling data obtained during a cruise in May 2014. Using a theoretical conservative mixing model, the surface CDOM in the PRE in spring is classified into two groups by the CDOM absorption-spectral slope relationship (a(300) vs S(275−295)): First, terrigenous CDOM under a non-conservative mixing condition, and removal processes such as photobleaching are suggested to happen; second, marine CDOM behaves conservatively during mixing. The mixing of CDOM at the bottom is shown to be conservative. Controlled by the two-layer gravitational circulation in the PRE, the northern and western estuary shows higher CDOM absorption and lower spectral slope than the southern and eastern estuary, and the surface CDOM presents higher absorption and lower spectral slope than the bottom. Horizontal transport is hypothesized to be the dominant hydrodynamic mechanism affecting CDOM variation and mixing behavior in the PRE, while the vertical mixing has less influence. Highlights: A theoretical, conservative mixing model is used to analyze the mixing behavior of CDOM in the PRE in Spring. The mixing of surface CDOM in the PRE of terrigenous origin is non-conservative and the photobleaching process occurs. The mixing of the surface CDOM of the marine origin and the mixing of the bottom CDOM in the PRE are conservative. Horizontal transport is a dominant hydrodynamic mechanism affecting CDOM variation and mixing in the PRE.