Vertical transport of dissolved oxygen under stratification constraints and its effect on hypoxic zone evolution
PEI Shengxin
LI Bo
WANG Kou
WANG Penghao
Abstract：The data of this paper were derived from continuous observation in the summer section of the Yangtze river estuary scientific investigation and experimental study(NORC2019-03-02)in July 2019.The distribution of hydrological environment elements in the sea area was analyzed and the vertical transport of dissolved oxygen over the pycnocline during the daily cycle was further estimated.It was found the distribution of hydrologic environment elements had obvious stratification structure,and the change of tidal current not only affected the distribution of hydrologic elements,but also caused the change of the position of thermocline.This paper calculated and analyzed about distribution of the buoyancy frequency square,turbulent energy dissipation rate e and vertical turbulent diffusion coeffi-cient Kz.using the equation of one-dimensional vertical transport of dissolved oxygen.The calculated cross-pycnocline transport of dissolved oxygen was 1.74 mmol/(m2·d).The sediment oxygen demand and plankton community respiration were introduced,proving the stratification of water was one of the main causes of low oxygen in the Yangtze estuary.
Keywords：Yangtze river estuaryhydrological environmentturbulent energy dissipation ratevertical turbulent diffusion coefficientdissolved oxygen vertical transport
Publication Date：2025-04-30
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：8( 85-92 )