Dynamics of the Toxic Dinoflagellate Alexandrium pacificum in the Taiwan Strait and Its Linkages to Surrounding Populations

The dinoflagellate Alexandrium pacificum can produce paralytic shellfish toxins and is mainly distributed in the Pacific. Blooms of A. pacificum have been frequently reported in offshore areas of the East China Sea, but not along the coast. To investigate the bloom dynamics of A. pacificum and their potential origins in the Taiwan Strait, we performed intensive sampling of both water and sediments from 2017 to 2020. Ellipsoidal cysts were identified as A. pacificum and enumerated based on microscopic observation. Their abundances were quite low but there was a maximum of 9.6 cysts cm−3 in the sediment near the Minjiang River estuary in May 2020, consistent with the high cell abundance in the water column in this area. Cells of A. pacificum were examined using a quantitative polymerase chain reaction, and they appeared to be persistent in the water column across the seasons. High densities of A. pacificum (103 cells L−1) were observed near the Jiulongjiang and Minjiang River estuary in early May 2020, where high nutrients (dissolved inorganic nitrogen and phosphate), and relatively low temperatures (20–21 °C) were also recorded. Strains isolated from the East and South China Sea exhibited the highest division rate (0.63 and 0.93 divisions d−1) at 20 and 23 °C, respectively, but the strain from the Yellow Sea showed the highest division (0.40 divisions d−1) at 17–23 °C. Strains from the East and South China Sea shared similar toxin profiles dominated by the N-sulfocarbamoyl toxins C1/2, but the strain from the Yellow Sea predominantly produced the carbamoyl toxins GTX1/4 and no C1/2. Our results suggest that both cyst germination and persistent cells in the water column might contribute to the bloom formation in the Taiwan Strait. Our results also indicate that the East and South China Sea populations are connected genetically through similar toxin formation but separated from the Yellow Sea population geographically.

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Cross-strait cooperation on search and rescue in the Taiwan Strait and its implication for the South China Sea

Securing the Safety of Navigation in East Asia ◽

10.1016/b978-0-85709-489-6.50012-4 ◽

2013 ◽

pp. 233-243 ◽

Cited By ~ 1

Author(s):

Fang Xu ◽

Pingping Chen

Keyword(s):

South China Sea ◽

South China ◽

Taiwan Strait ◽

The South China Sea ◽

Search And Rescue ◽

The South ◽

China Sea ◽

The Taiwan Strait

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Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-10905-2015 ◽

2015 ◽

Vol 15 (18) ◽

pp. 10905-10924 ◽

Cited By ~ 27

Author(s):

Y. Zhao ◽

L. Zhang ◽

Y. Pan ◽

Y. Wang ◽

F. Paulot ◽

...

Keyword(s):

South China Sea ◽

Nitrogen Deposition ◽

South China ◽

Yellow Sea ◽

The South China Sea ◽

The Yellow Sea ◽

Northwestern Pacific ◽

Atmospheric Nitrogen Deposition ◽

Atmospheric Nitrogen ◽

China Sea

Abstract. Rapid Asian industrialization has led to increased downwind atmospheric nitrogen deposition threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2° × 2/3° horizontal resolution over East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a−1 as NH3 and 15.7 Tg N a−1 as NOx. China has the largest sources with 12.8 Tg N a−1 as NH3 and 7.9 Tg N a−1 as NOx; the high-NH3 emissions reflect its intensive agricultural activities. We find Asian NH3 emissions are a factor of 3 higher in summer than winter. The model simulation for 2008–2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8–20 kg N ha−1 a−1, decreasing rapidly downwind of the Asian continent. Deposition fluxes average 11.9 kg N ha−1 a−1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha−1 a−1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7 % over the South China Sea, and become important (greater than 30 %) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian monsoon and in nitrogen emissions. The model adjoint further estimates that nitrogen deposition to the Yellow Sea originates from sources over China (92 % contribution) and the Korean peninsula (7 %), and by sectors from fertilizer use (24 %), power plants (22 %), and transportation (18 %). Deposition to the South China Sea shows source contribution from mainland China (66 %), Taiwan (20 %), and the rest (14 %) from the southeast Asian countries and oceanic NH3 emissions. The adjoint analyses also indicate that reducing Asian NH3 emissions would increase NOy dry deposition to the Yellow Sea (28 % offset annually), limiting the effectiveness of NH3 emission controls on reducing nitrogen deposition to the Yellow Sea.

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Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-13657-2015 ◽

2015 ◽

Vol 15 (9) ◽

pp. 13657-13703 ◽

Cited By ~ 6

Author(s):

Y. H. Zhao ◽

L. Zhang ◽

Y. P. Pan ◽

Y. S. Wang ◽

F. Paulot ◽

...

Keyword(s):

South China Sea ◽

Nitrogen Deposition ◽

South China ◽

Yellow Sea ◽

The South China Sea ◽

The Yellow Sea ◽

Northwestern Pacific ◽

Atmospheric Nitrogen Deposition ◽

Atmospheric Nitrogen ◽

China Sea

Abstract. Rapid Asian industrialization has led to increased atmospheric nitrogen deposition downwind threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2° × 2/3° horizontal resolution over the East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a−1 as NH3 and 15.7 Tg N a−1 as NOx. China has the largest sources with 12.8 Tg N a−1 as NH3 and 7.9 Tg N a−1 as NOx; the high NH3 emissions reflect its intensive agricultural activities. We find Asian NH3 emissions are a factor of 3 higher in summer than winter. The model simulation for 2008–2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8–20 kg N ha−1 a−1, decreasing rapidly downwind the Asian continent. Deposition fluxes average 11.9 kg N ha−1 a−1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha−1 a−1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7% over the South China Sea, and become important (greater than 30%) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian Monsoon and in nitrogen emissions. The model adjoint further estimates that nitrogen deposition to the Yellow Sea originates from sources over China (92% contribution) and the Korean peninsula (7%), and by sectors from fertilizer use (24%), power plants (22%), and transportation (18%). Deposition to the South China Sea shows source contribution from Mainland China (66%), Taiwan (20%), and the rest 14% from the Southeast Asian countries and oceanic NH3 emissions. The adjoint analyses also indicate that reducing Asian NH3 emissions would increase NOy dry deposition to the Yellow Sea (28% offset annually), limiting the effectiveness of NH3 emission controls.

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Spatially Explicit Inventory of Sources of Nitrogen Inputs to the Yellow Sea, East China Sea, and South China Sea for the Period 1970–2010

Earth s Future ◽

10.1029/2020ef001516 ◽

2020 ◽

Vol 8 (10) ◽

Author(s):

Junjie Wang ◽

Arthur H. W. Beusen ◽

Xiaochen Liu ◽

Rita Van Dingenen ◽

Frank Dentener ◽

...

Keyword(s):

South China Sea ◽

East China Sea ◽

South China ◽

Yellow Sea ◽

The Yellow Sea ◽

East China ◽

Spatially Explicit ◽

China Sea ◽

Nitrogen Inputs

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Supplementary material to "Contrasting responses of phytoplankton productivity between coastal and offshore surface waters in the Taiwan Strait and the South China Sea to future CO<sub>2</sub>-induced acidification"

10.5194/bg-2021-326-supplement ◽

2022 ◽

Author(s):

Guang Gao ◽

Tifeng Wang ◽

Jiazhen Sun ◽

Xin Zhao ◽

Lifang Wang ◽

...

Keyword(s):

South China Sea ◽

South China ◽

Surface Waters ◽

Taiwan Strait ◽

The South China Sea ◽

The South ◽

Phytoplankton Productivity ◽

China Sea ◽

Supplementary Material ◽

The Taiwan Strait

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Morphology and bloom dynamics of Cochlodinium geminatum (Schütt) Schütt in the Pearl River Estuary, South China Sea

Harmful Algae ◽

10.1016/j.hal.2011.09.009 ◽

2012 ◽

Vol 13 ◽

pp. 10-19 ◽

Cited By ~ 16

Author(s):

Ping-Ping Shen ◽

Ya-Nan Li ◽

Yu-Zao Qi ◽

Lv-Ping Zhang ◽

Ye-Hui Tan ◽

...

Keyword(s):

South China Sea ◽

South China ◽

River Estuary ◽

Pearl River Estuary ◽

Pearl River ◽

China Sea ◽

The Pearl River Estuary ◽

The Pearl River

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

The Holocene ◽

10.1177/09596836211003229 ◽

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.

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Impact of the Kuroshio intrusion on the nutrient inventory in the upper northern South China Sea: insights from an isopycnal mixing model

Biogeosciences ◽

10.5194/bg-10-6419-2013 ◽

2013 ◽

Vol 10 (10) ◽

pp. 6419-6432 ◽

Cited By ~ 59

Author(s):

C. Du ◽

Z. Liu ◽

M. Dai ◽

S.-J. Kao ◽

Z. Cao ◽

...

Keyword(s):

South China Sea ◽

Water Column ◽

South China ◽

Water Mass ◽

Northern South China Sea ◽

Mixing Model ◽

Nutrient Concentrations ◽

Kuroshio Intrusion ◽

China Sea ◽

The Kuroshio

Abstract. Based on four cruises covering a seasonal cycle in 2009–2011, we examined the impact of the Kuroshio intrusion, featured by extremely oligotrophic waters, on the nutrient inventory in the central northern South China Sea (NSCS). The nutrient inventory in the upper 100 m of the water column in the study area ranged from ∼200 to ∼290 mmol m−2 for N + N (nitrate plus nitrite), from ∼13 to ∼24 mmol m−2 for soluble reactive phosphate and from ∼210 to ∼430 mmol m−2 for silicic acid. The nutrient inventory showed a clear seasonal pattern with the highest value appearing in summer, while the N + N inventory in spring and winter had a reduction of ∼13 and ∼30%, respectively, relative to that in summer. To quantify the extent of the Kuroshio intrusion, an isopycnal mixing model was adopted to derive the proportional contribution of water masses from the SCS proper and the Kuroshio along individual isopycnal surfaces. The derived mixing ratio along the isopycnal plane was then employed to predict the genuine gradients of nutrients under the assumption of no biogeochemical alteration. These predicted nutrient concentrations, denoted as Nm, are solely determined by water mass mixing. Results showed that the nutrient inventory in the upper 100 m of the NSCS was overall negatively correlated to the Kuroshio water fraction, suggesting that the Kuroshio intrusion significantly influenced the nutrient distribution in the SCS and its seasonal variation. The difference between the observed nutrient concentrations and their corresponding Nm allowed us to further quantify the nutrient removal/addition associated with the biogeochemical processes on top of the water mass mixing. We revealed that the nutrients in the upper 100 m of the water column had a net consumption in both winter and spring but a net addition in fall.

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