Factors Contributing to Hypoxia in the Minjiang River Estuary, Southeast China

Abstract

Dissolved oxygen (DO) is not only a fundamental parameter of coastal water quality, but also an indication of organics decomposed in water and their degree of eutrophication. There has been a concern about the deterioration of dissolved oxygen conditions in the Minjiang River Estuary, the longest river in Fujian Province, Southeast China. In this study, the syntheses effects on DO was analyzed by using a four year time series of DO concentration and ancillary parameters (river discharge, water level, and temperature) from the Fuzhou Research Academy of Environmental Sciences, at three automated stations along the Minjiang River Estuary. Hypoxia occurred exclusively in the fluvial sections of the estuary during the high temperature and low river discharge period and was remarkably more serious in the river reach near the large urban area of Fuzhou. Enhancement of respiration by temperature and discharge of domestic sewage and industrial wastewater, versus regeneration of waters and dilution of pollutant concentration with increased river discharge, which regarded as the dominant antagonist processes that controlled the appearance of seasonal hypoxia. During the high temperature and the drought period, minimal mainstream flow above 700 m3·s−1, reduction of pollutants and forbidding sediment dredging in the South Channel should be guaranteed for strong supports on water quality management and drinking water source protection.

Impact of urban effluents on summer hypoxia in the highly turbid Gironde Estuary, applying a 3D model coupling hydrodynamics, sediment transport and biogeochemical processes

“…Our result is consistent with the literature, that reports greater hypoxia near large urban areas (Amann et al, 2012;Garnier et al, 2001;Soetaert et al, 2006;Tinsley, 1998;Zhang et al, 2015). In the Gironde Estuary, the same observation was reported by Etcheber et al (2011) and Lanoux et al (2013).…”

Exploring the Susceptibility of Turbid Estuaries to Hypoxia as a Prerequisite to Designing a Pertinent Monitoring Strategy of Dissolved Oxygen

“…Nantes and Bordeaux, respectively (Figure 1). Hypoxia is often reported in the vicinities of such large cities, due to the input of organic matter and nutrients from wastewater discharges (Garnier et al, 2001;Zhang et al, 2015). The multiyear continuous record of dissolved oxygen in Nantes (Trentemoult site) and Bordeaux presents the same multiscale variability (Figure 2).…”

Influence of Riverbed Incision and Hydrological Evolution on Water Quality and Water Age Based on Numerical Simulation: A Case Study of the Minjiang Estuary

“…Yao et al [ 16 ] studied the waterway maintenance, and a new waterway excavation project in Lingdingyang Bay has a significant impact on underwater topography and beach evolution, resulting in the river topography the shallower the shoal, the deeper the deep channel. The dredging of the downstream channel of the Minjiang River and sand mining of the channel have led to serious riverbed cutting, changes in the hydrodynamic conditions of the South Channel and the North Channel, and threats to the safety of the embankment [ 17 ].…”