scholarly journals Biogeographical Distribution and Community Assembly of Active Protistan Assemblages along an Estuary to a Basin Transect of the Northern South China Sea

2021 ◽  
Vol 9 (2) ◽  
pp. 351
Author(s):  
Ran Li ◽  
Chen Hu ◽  
Jianning Wang ◽  
Jun Sun ◽  
Ying Wang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Water Depth ◽  
High Throughput Sequencing ◽  
Northern South China Sea ◽  
Regional Scale ◽  
River Estuary ◽  
Variable Regions ◽  
China Sea ◽  
Biogeographical Distribution

Marine protists are essential for globally critical biological processes, including the biogeochemical cycles of matter and energy. However, compared with their prokaryotic counterpart, it remains largely unclear how environmental factors determine the diversity and distribution of the active protistan communities on the regional scale. In the present study, the biodiversity, community composition, and potential drivers of the total, abundant, and rare protistan groups were studied using high throughput sequencing on the V9 hyper-variable regions of the small subunit ribosomal RNA (SSU rRNA) along an estuary to basin transect in the northern South China Sea. Overall, Bacillariophyta and Cercozoa were abundant in the surface water; heterotrophic protists including Spirotrichea and marine stramenopiles 3 (MAST-3) were more abundant in the subsurface waters near the heavily urbanized Pearl River estuary; Chlorophyta and Pelagophyceae were abundant at the deep chlorophyll maximum depth, while Hacrobia, Radiolaria, and Excavata were the abundant groups in the deep water. Salinity, followed by water depth, temperature, and other biological factors, were the primary factors controlling the distinct vertical and horizontal distribution of the total and abundant protists. Rare taxa were driven by water depth, followed by temperature, salinity, and the concentrations of PO43−. The active protistan communities were mainly driven by dispersal limitation, followed by drift and other ecological processes.

A preliminary study on sediment records of possible typhoon in the northern South China Sea during the past 6500 yr

The Holocene ◽  
2021 ◽  
pp. 095968362110032
Author(s):  
Pingyuan Li ◽  
Mingkun Li ◽  
Huayang Gan ◽  
Zhen Xia
Keyword(s):  
South China Sea ◽  
South China ◽  
Southern China ◽  
Northern South China Sea ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Human Beings ◽  
China Sea ◽  
The Pearl River ◽  
China Coast

Typhoon is an important meteorological phenomenon that affects the living and development of human beings on the southern China coast. However, there is still lack of clarity in the paleo-typhoon history and its influence on the evolution of the ancient human settlement environment since the mid-Holocene. Here, we identify six typhoon-like deposits from a core retrieved from the northern South China Sea shelf, close to the Pearl River Estuary, based on accelerated mass spectrometry 14C dating, grain size, and geochemistry. The sand fractions, CaO, Sr, SiO2/TiO2, and SiO2/Al2O3 were used to indicate the typhoon-like deposits. Results show that the ages with high-frequency typhoons are present ~200–300 cal yr BP, ~800–1000 cal yr BP, ~1500–1700 cal yr BP, ~2000–2100 cal yr BP, ~2400–2500 cal yr BP, and ~2700–3000 cal yr BP. Our results are comparable to the records from adjacent regions. Significantly, the vast tides occurred in the duration of ~2700–3000 cal yr BP in southern China, which probably caused the ancestors’ migration to the inland. Further studies are needed to deeply study the paleo-typhoon history in the southern China coast to verify our results.

scholarly journals Phytoplankton growth and physiological responses to a plume front in the northern South China Sea

2017 ◽  
Author(s):  
Qian P. Li ◽  
Weiwen Zhou ◽  
Yinchao Chen ◽  
Zhengchao Wu
Keyword(s):  
South China Sea ◽  
South China ◽  
Bottom Water ◽  
Frontal Zone ◽  
Northern South China Sea ◽  
River Estuary ◽  
Phytoplankton Growth ◽  
Frontal System ◽  
China Sea ◽  
Plume Water

Abstract. Due to a strong river discharge during April–June 2016, a persistent salinity front, with freshwater flushing seaward on the surface but seawater moving landward at the bottom, was formed in the coastal waters west of the Pearl River Estuary (PRE) over the Northern South China Sea (NSCS) shelf. Hydrographic measurements revealed that the salinity front was influenced by both river plume and coastal upwelling. Shipboard nutrient-enrichment experiments with size-fractionation chlorophyll-a measurements were performed on both sides of the front as well as the front zone to diagnose the spatial variations of phytoplankton physiology across the frontal system. We also assessed the size-fractionated responses of phytoplankton to the treatment of plume water at the frontal zone and the seaside of the front. Biological impact of vertical mixing or upwelling was further examined by the response of surface phytoplankton to the addition of local bottom water. Our results suggested that there was a large variation of phytoplankton physiology on the seaside of the front driven by dynamic nutrient fluxes, although P-limitation was prevailing on the shore-side of the front and at the frontal zone. The spreading of plume water at the frontal zone would directly improve the growth of micro-phytoplankton, while nano- and pico-phytoplankton growths could become saturated at high percentages of plume water. Also, the mixing of bottom water would stimulate the growth of surface phytoplankton on both sides of the front by altering the surface N / P ratio closer to the Redfield stoichiometry. In summary, phytoplankton growth and physiology could be profoundly influenced by physical dynamics of the frontal system during the spring–summer of 2016.

Dynamics of heterotrophic dinoflagellates off the Pearl River Estuary, northern South China Sea

2009 ◽  
Vol 85 (3) ◽  
pp. 422-430 ◽  
Author(s):  
Wenlu Lan ◽  
Bangqin Huang ◽  
Minhan Dai ◽  
Xiuren Ning ◽  
Lingfeng Huang ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River ◽  
China Sea ◽  
The Pearl River Estuary ◽  
The Pearl River

Factors controlling nitrous oxide in the inner Pearl River Estuary, Northern South China Sea

2012 ◽  
Vol 15 (2) ◽  
pp. 176-184 ◽  
Author(s):  
You-Shao Wang ◽  
Mei-Lin Wu ◽  
Ji-Rong Xu ◽  
Cui-Ci Sun ◽  
Jun-De Dong ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River ◽  
China Sea

Spatial shifts in size structure, phylogenetic diversity, community composition and abundance of small eukaryotic plankton in a coastal upwelling area of the northern South China Sea

2020 ◽  
Author(s):  
Fahui Gong ◽  
Guihao Li ◽  
Yaping Wang ◽  
Qinyu Liu ◽  
Fangjuan Huang ◽  
...  
Keyword(s):  
South China Sea ◽  
Spatial Patterns ◽  
South China ◽  
High Throughput Sequencing ◽  
Size Structure ◽  
Northern South China Sea ◽  
Rrna Genes ◽  
Inner Shelf ◽  
Cell Abundance ◽  
China Sea

Abstract Summer upwelling off Hainan Island (northern South China Sea) is influenced by fresher coastal water masses. To assess the ecological effects of this complicated oceanography, a cruise was conducted in August 2016. We investigated the spatial patterns of phytoplankton size structure, diversity and quantity of small eukaryotes (0.2–20 μm) across the upwelling system. In the inner-shelf waters, nanophytoplankton contributed a higher proportion to phytoplankton biomass than microphytoplankton and picophytoplankton. High-throughput sequencing of 18S rRNA genes and community analysis indicated that the horizontal variation in community structure of small eukaryotes was larger than the vertical. The relative sequence proportions of dinoflagellates, diatoms, ciliates and Micromonas in the surface layer gradually decreased from the inner shelf to the slope, whereas the Rhizaria, Bathycoccus and Ostreococcus exhibited an opposite trend. The spatial patterns of taxon-specific rDNA copy numbers were similar to the patterns based on the relative proportions. Redundancy analysis revealed that turbidity, salinity and ${\mathrm{NO}}_3^{-}$ were the most important environmental variables in structuring the community of small eukaryotes. The cell abundance of photosynthetic picoeukaryotes was significantly correlated with the rDNA abundance of Mamiellophyceae and the cell abundance of nanoeukaryotes was significantly correlated with the rDNA abundance of dinoflagellates plus diatoms.

scholarly journals Coupling of surface <i>p</i>CO<sub>2</sub> and dissolved oxygen in the northern South China Sea: impacts of contrasting coastal processes

2009 ◽  
Vol 6 (3) ◽  
pp. 6249-6269 ◽  
Author(s):  
W. Zhai ◽  
M. Dai ◽  
W. Cai
Keyword(s):  
South China Sea ◽  
Dissolved Oxygen ◽  
South China ◽  
Coastal Upwelling ◽  
Northern South China Sea ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Deep Basin ◽  
Co2 Partial Pressure ◽  
China Sea

Abstract. We examined the relationship between CO2 partial pressure (pCO2) and dissolved oxygen (DO) based on a cruise conducted in July 2004 to the northern South China Sea, spanning from estuarine plume, coastal upwelling and deep basin areas. Distinct relationships between pCO2 and DO saturation were identified in different regimes. In coastal upwelling areas and the Pearl River estuary, biological drawdown of pCO2 and production of O2 were simultaneously observed. The two properties were coupled with each other primarily via photosynthesis and respiration. The stoichiometric relationship of the two properties however, was quite different in these two environments due to different values of the Revelle factor. In the offshore areas, apart from the estuary and upwelling, the dynamics of pCO2 and DO were mainly influenced by air-sea exchange during water mixing. Given the fact that air-sea re-equilibration of O2 is much faster than that of CO2, the observed pCO2-DO relationship deviated from that of the theoretical prediction based on the Redfield relationship in the offshore areas.

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