Contribution of Mountain River Materials to the Continental Shelf off Southeastern Hainan Island Since the Mid-Holocene

The seasonal and spatial variations of cladocerans were studied based on samples collected with 169 μm mesh plankton nets from July to August 2006 (summer), December 2006 to January 2007 (winter), and in April 2007 (spring) on the northwestern continental shelf of the South China Sea. Three species of cladocerans (Pseudevadne tergestina, Penilia avirostris, and Podon schmackeri) were observed. Cladocerans occur in spring and summer, but not in winter. They showed an average abundance of 12.82 (± 48.44) inds m−3 in spring and 64.66 (± 188.82) inds m−3 in summer. P. avirostris occurred in the inshore waters of the Leizhou Peninsula during spring, but in summer they were found in large number along the inshore waters from Leizhou Peninsula to the southeast of Hainan Island, with the highest abundance (1121.50 inds m−3). P. tergestina was the most dominant species both in spring and summer, being widely distributed throughout the whole surveyed area. P. schmackeri was distributed mainly along the inshore waters of the Leizhou Peninsula during spring, and mainly along the inshore waters of Hainan Island during the summer (with low density). Our results suggest that the unstable water environment resulting from the strong northeastern monsoon in winter may explain the absence of cladocerans in a large area of the northwest continental shelf of the South China Sea. High chlorophyll a concentration owing to physical factors (e.g., cold eddy, coastal upwelling and mixing) may be the main reason for the difference in the spatial distribution of cladocerans in the subtropical and tropical areas of our survey.

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A 1900‐year record of mercury (Hg) from the east continental shelf of Hainan Island, South China Sea

Geological Journal ◽

10.1002/gj.3678 ◽

2019 ◽

Vol 55 (6) ◽

pp. 4469-4478

Author(s):

Chao Ji ◽

Liqiang Xu ◽

Yihui Zhang ◽

Min Guo ◽

Deming Kong

Keyword(s):

South China Sea ◽

Continental Shelf ◽

South China ◽

Hainan Island ◽

China Sea

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Rare Earth Element Distributions in Continental Shelf Sediment, Northern South China Sea

Water ◽

10.3390/w12123540 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3540

Author(s):

Qian Ge ◽

Z. George Xue ◽

Fengyou Chu

Keyword(s):

Rare Earth ◽

South China Sea ◽

Continental Shelf ◽

South China ◽

Northern South China Sea ◽

Hainan Island ◽

Sediment Provenance ◽

Adjacent Area ◽

China Sea ◽

Qiongzhou Strait

A total of 388 surface sediment samples taken from the northern South China Sea (SCS) continental shelf were analyzed to characterize the signature of their rare earth elements (REEs). The average REEs concentration was 192.94 μg/g, with a maximum of 349.07 μg/g, and a minimum of 32.97 μg/g. The chondrite-normalized REEs pattern exhibits a remarkably light REEs accumulation, a relatively flat heavy REEs pattern, and a negative Eu anomaly. We subdivided the study area into three zones using the characteristics of REEs and statistical characteristics. Zone I: continental shelf off western Guangdong Province. Here, the sediment provenance is mainly river-derived from the Pearl River, Taiwanese rivers, and those in the adjacent area. Zone II: Qiongzhou Strait and Leizhou Peninsula. Here, the sediment provenance consists of the Qiongzhou Strait and the Hainan Island. Zone III: Hainan Island and SCS slope sediments are dominated. The REEs compositions are mainly controlled by source rock properties, hydrodynamic conditions, and an intensity of chemical weathering. We reconstructed the sediment dispersal and transport route using the REEs compositions, grain size, and other geochemical characteristics throughout the study area.

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