Recent oxygen depletion in the Pearl River Estuary, South China: geochemical and microfaunal evidence

Feng, Ye; Huang, Xiaoping; Zhang, Xia; Zhang, Dawen; Zeng, Yanyi; Tian, Lei

doi:10.1007/s10872-012-0104-1

Cited by 22 publications

(15 citation statements)

References 58 publications

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“…As such, eutrophication has increasingly become an issue of concern (Huang et al, 2003;Ye et al, 2012). Dissolved inorganic nitrogen (DIN) concentrations in the PRE increased approximately 4-fold from 1986 (19.3 µmol L −1 ) to 2002 (76.1 µmol L −1 ) (He and Yuan, 2007).…”

Section: Introductionmentioning

confidence: 99%

Tracing the origin of the oxygen-consuming organic matter in the hypoxic zone in a large eutrophic estuary: the lower reach of the Pearl River Estuary, China

Dai

et al. 2017

Biogeosciences

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Abstract. We assess the relative contributions of different sources of organic matter, marine vs. terrestrial, to oxygen consumption in an emerging hypoxic zone in the lower Pearl River Estuary (PRE), a large eutrophic estuary located in Southern China. Our cruise, conducted in July 2014, consisted of two legs before and after the passing of Typhoon Rammasun, which completely de-stratified the water column. The stratification recovered rapidly, within 1 day after the typhoon. We observed algal blooms in the upper layer of the water column and hypoxia underneath in bottom water during both legs. Repeat sampling at the initial hypoxic station showed severe oxygen depletion down to 30 µmol kg −1 before the typhoon and a clear drawdown of dissolved oxygen after the typhoon. Based on a three endmember mixing model and the mass balance of dissolved inorganic carbon and its isotopic composition, the δ 13 C of organic carbon remineralized in the hypoxic zone was −23.2 ± 1.1 ‰. We estimated that 65 ± 16 % of the oxygen-consuming organic matter was derived from marine sources, and the rest (35 ± 16 %) was derived from the continent. In contrast to a recently studied hypoxic zone in the East China Sea off the Changjiang Estuary where marine organic matter dominated oxygen consumption, here terrestrial organic matter significantly contributed to the formation and maintenance of hypoxia. How varying amounts of these organic matter sources drive oxygen consumption has important implications for better understanding hypoxia and its mitigation in bottom waters.

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Section: Introductionmentioning

confidence: 99%

Tracing the origin of the oxygen-consuming organic matter in the hypoxic zone in a large eutrophic estuary: the lower reach of the Pearl River Estuary, China

Dai

et al. 2017

Biogeosciences

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“…However, sediment accumulation rates are 1.65 cm/year in the Pearl River estuary (Ye et al, 2012), and 0.29, 0.062, and 0.011 cm/year in the NSCS inner shelf, outer shelf, and slope (Zhao et al, 2009). This indicates that the buried OM in the 0 to 5 cm depth interval represents years to centuries of sediment accumulation, during which time physical processes and bioturbation will thoroughly mix the upper layers of the sediments.…”

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confidence: 96%

Sources, distributions, and early diagenesis of sedimentary organic matter in the Pearl River region of the South China Sea

Zhang

Kaiser

et al. 2014

Marine Chemistry

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“…Overall, TOC levels are lower in the surface sediments in most estuaries in China, relative to those in the South and Southeast Asia 40 , 41 , Europe 42 , 43 , North America and South America 44 , 45 . In general, sedimentary TOC concentration is relatively lower in large river estuaries (e.g., the Yangtze River Estuary 46 , 47 and Pearl River Estuary 48 , 49 ) than in small river estuaries (e.g., the Luan River Estuary 50 , Licun Estuary 51 , Min River Estuary 52 and GQ Estuary 53 ), which indicating that weak hydrodynamic environment (in the small estuaries) was beneficial to accumulation of organic carbon 11 , 54 .…”

Section: Discussionmentioning

confidence: 96%

Organic and inorganic carbon and their stable isotopes in surface sediments of the Yellow River Estuary

Wang

Liu

et al. 2018

Sci Rep

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Studying the carbon dynamics of estuarine sediment is crucial to understanding of carbon cycle in the coastal ocean. This study is to evaluate the mechanisms regulating the dynamics of organic (TOC) and inorganic carbon (TIC) in surface sediment of the Yellow River Estuary (YRE). Based on data of 15 surface sediment cores, we found that TIC (6.3–20.1 g kg−1) was much higher than TOC (0.2–4.4 g kg−1). Both TOC and TIC were generally higher to the north than to the south, primarily due to the differences in kinetic energy level (i.e., higher to the south). Our analysis suggested that TOC was mainly from marine sources in the YER, except in the southern shallow bay where approximately 75% of TOC was terrigenous. The overall low levels of TOC were due to profound resuspension that could cause enhanced decomposition. On the other hand, high levels of TIC resulted partly from higher rates of biological production, and partly from decomposition of TOC associated with sediment resuspension. The isotopic signiture in TIC seems to imply that the latter is dominant in forming more TIC in the YRE, and there may be transfer of OC to IC in the water column.

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Recent oxygen depletion in the Pearl River Estuary, South China: geochemical and microfaunal evidence

Cited by 22 publications

References 58 publications

Tracing the origin of the oxygen-consuming organic matter in the hypoxic zone in a large eutrophic estuary: the lower reach of the Pearl River Estuary, China

Tracing the origin of the oxygen-consuming organic matter in the hypoxic zone in a large eutrophic estuary: the lower reach of the Pearl River Estuary, China

Sources, distributions, and early diagenesis of sedimentary organic matter in the Pearl River region of the South China Sea

Organic and inorganic carbon and their stable isotopes in surface sediments of the Yellow River Estuary

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