Oxygen depletion in the upper reach of the Pearl River estuary during a winter drought

Dai, Minhan; Guo, Xianghui; Zhai, Weidong; Liang-ying, Yuan; Wang, Bengwang; Wang, Lifang; Cai, Pinghe; Tang, Tiantian; Cai, Wei‐Jun

doi:10.1016/j.marchem.2005.09.020

Cited by 226 publications

(187 citation statements)

References 26 publications

Supporting

Mentioning

171

Contrasting

Unclassified

Order By: Relevance

“…The concentrations of Cu, Pb, Zn, Cd, and Ag were much higher in core 2 than in cores 3 and 4. Meanwhile, the lower value of DO and higher value of turbidity were also recorded at site 2 (Table 1), which was consistent with the previous study (Dai et al 2006). The persistent hypoxia in upstream of the channel in Guangzhou caused by organic pollution and nitrification was demonstrated (Luo 2002).…”

Section: Geochemistry Of Trace Elements and Mn In Sedimentssupporting

confidence: 91%

Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches

Yang

Liu

Chen

et al. 2014

Environ Monit Assess

View full text Add to dashboard Cite

Twenty-four major and trace elements and the mineralogical composition of four sediment cores along the Pearl River and estuary were analyzed using ICP-AES, ICP-MS, and X-ray diffraction (XRD) to evaluate contamination levels. The dominant minerals were quartz, kaolinite, and illite, followed by montmorillonite and feldspars, while small amounts of halite and calcite were also observed in a few samples. Cluster analysis (CA) and principal component analysis (PCA) were performed to identify the element sources. The highest metal concentrations were found at Huangpu, primarily due to wastewater treatment plant discharge and/or the surreptitious dumping of sludge, and these data differed from those of other sources. Excluding the data from Huangpu, the PCA showed that most elements could be considered as lithogenic; few elements are the combination of lithogenic and anthropogenic sources. An antagonistic relationship between the anthropogenic source metals (K, Ba, Zn, Pb, Cd, Ag, Tl, and U) and marine source metals (Na, Mg, Ti, V, and Ca) was observed. The resulting normalized Al enrichment factor (EF) indicated very high or significant pollution of Cd, Ag, Cu, Zn, Mo, and Pb at Huangpu, which may cause serious environmental effects. Conflicting results between the PCA and EF can be attributed to the background values used, indicating that background values must be selected carefully.

show abstract

Section: Geochemistry Of Trace Elements and Mn In Sedimentssupporting

confidence: 91%

Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches

Yang

Liu

Chen

et al. 2014

Environ Monit Assess

View full text Add to dashboard Cite

show abstract

“…Coastal waters can be susceptible to upwelling of hypoxic water from elsewhere, as in the California Current system off the west coast of North America (Grantham et al 2004;Bianucci and Denman 2012), or to a change in stratification due to winter warming of surface water, as has been observed in the Japan Sea (Kang et al 2004). In some coastal areas, such as the East China Sea (Chen et al 2007), South China Sea (Dai et al 2006), Gulf of Mexico (Rabalais et al 2001), and the lower Saint Lawrence estuary (Gilbert et al 2010), physical circulation has contributed the conditions necessary to support deoxygenation, while eutrophication caused by the discharge of municipal wastewater or agricultural runoff (Falkowski et al 2011) has provided a local stress that has pushed these areas into hypoxia.…”

mentioning

confidence: 99%

Oxygen in the deep Strait of Georgia, 1951–2009: The roles of mixing, deep‐water renewal, and remineralization of organic carbon

Johannessen¹,

Masson²,

Macdonald³

2014

Limnology & Oceanography

View full text Add to dashboard Cite

The concentration of oxygen in the deep Strait of Georgia has declined at a rate of 0.45-1.3 mmol L 21 yr 21 since 1971 and now seasonally approaches thresholds of biological tolerance. The decline has resulted principally from the increasing hypoxia of upwelled Pacific Ocean water. Local anthropogenic loadings have little potential to reduce bottom water oxygen concentrations. Hypoxic, upwelled water mixes vigorously with surface water in the tidal passages of Haro Strait before entering the deep Strait of Georgia during a series of deep-water renewal events in late spring and late summer. Remineralization of at least 22 mmol L 21 yr 21 , together with diffusive mixing, reduces the bottom water oxygen concentration to a winter minimum of 90-110 mmol L 21 . Linear extrapolation of the long-term trend indicates that parts of the Strait could become episodically hypoxic (, 62.5 mmol L 21 ; , 1.4 mL L 21 ) as early as 2042. However, water mass modeling shows that the mixing with surface water in Haro Strait limits the potential of the shelf water to reduce the oxygen concentration in the deep Strait; even should the shelf water become completely anoxic, the concentration of oxygen in bottom waters would level off just above 90 mmol L 21 after 3 yr. Increasing surface water temperature will reduce the solubility of oxygen, but this effect is projected to cause a further decline of only 2.2 mmol L 21 over the next 25 yr. Despite its restricted circulation, the deep Strait of Georgia is less threatened by hypoxia than are many other coastal areas, because of the combination of light-limited primary production and intense tidal mixing in the approaches, which replenishes the deep-water oxygen annually.

show abstract

“…Coupled with the monsoonal influence, the seasonal freshwater discharge from the Pearl River further complicates the hydrodynamics and biochemical processes. Previous studies suggested that the anthropogenic inputs of nutrients and organic matter in the Pearl River estuary have led to a decrease in oxygen and an increase in CO 2 , especially in the upper estuary (Yin et al, 2004;Cai et al, 2004;Dai et al, 2006). Zhai et al (2005a) have reported that aerobic respiration is the most important process in maintaining a high pCO 2 level (>3000 µatm) in the upstream section of the Pearl River estuary.…”

mentioning

confidence: 99%

Influence of seasonal monsoons on net community production and CO<sub>2</sub> in subtropical Hong Kong coastal waters

et al. 2011

View full text Add to dashboard Cite

Abstract. Data from seven cruises in three different environments including the Pearl River estuary, sewage discharge outfall, and eastern coastal/shelf waters were used to examine the seasonal variations in net community production (NCP) and the biologically active gases O 2 and CO 2 . In the winter dry season, when monsoon-induced downwelling was dominant, NCP was negative (−84 ± 50 mmol C m −2 d −1 ) in all three regions. The negative NCP corresponded to O 2 influxes of 100 ± 50 mmol O 2 m −2 d −1 and CO 2 effluxes of 24 ± 10 mmol C m −2 d −1 . In the summer wet season, when upwelling brought the deep oceanic waters to the coast due to the southwest monsoonal winds, there was a 2 to 15-fold increase in integrated primary production (IPP) compared to winter. The increase in IPP was likely due to the favorable conditions such as stratification and the nutrient inputs from upwelled waters and the Pearl River estuary. NCP in the mixed layer reached up to 110 ± 48 mmol C m −2 d −1 in the wet season. However, accompanying the high positive NCP, we observed an O 2 influx of 100 ± 60 mmol O 2 m −2 d −1 and CO 2 efflux of 21 ± 15 mmol C m −2 d −1 . The contradictory observation of positive NCP and CO 2 release and O 2 uptake in the mixed layer could be explained by the influence of the southwest monsoon-induced upwelling along with the influence of the Pearl River, as the upwelling brought cold, low dissolved oxygen (DO, 160 ± 30 µM) and high dissolved inorganic carbon (DIC, 1960 ± 100 µatm) water to the surface in the wet season. Hence, the subtropical Hong KongCorrespondence to: K. Yin (yinkd@mail.sysu.edu.cn) coastal waters are generally a CO 2 source due to the monsoonal influence during both the dry-heterotrophic and wetautotrophic seasons.

show abstract

Oxygen depletion in the upper reach of the Pearl River estuary during a winter drought

Cited by 226 publications

References 26 publications

Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches

Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches

Oxygen in the deep Strait of Georgia, 1951–2009: The roles of mixing, deep‐water renewal, and remineralization of organic carbon

Influence of seasonal monsoons on net community production and CO<sub>2</sub> in subtropical Hong Kong coastal waters

Contact Info

Product

Resources

About

Oxygen depletion in the upper reach of the Pearl River estuary during a winter drought

Cited by 226 publications

References 26 publications

Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches

Assessment of trace element contamination in sediment cores from the Pearl River and estuary, South China: geochemical and multivariate analysis approaches

Oxygen in the deep Strait of Georgia, 1951–2009: The roles of mixing, deep‐water renewal, and remineralization of organic carbon

Influence of seasonal monsoons on net community production and CO&lt;sub&gt;2&lt;/sub&gt; in subtropical Hong Kong coastal waters

Contact Info

Product

Resources

About

Influence of seasonal monsoons on net community production and CO<sub>2</sub> in subtropical Hong Kong coastal waters