scholarly journals Seasonal distributions and fluxes of <sup>210</sup>Pb and <sup>210</sup>Po in the northern South China Sea

2014 ◽  
Vol 11 (23) ◽  
pp. 6813-6826 ◽  
Author(s):  
C.-L. Wei ◽  
M.-C. Yi ◽  
S.-Y. Lin ◽  
L.-S. Wen ◽  
W.-H. Lee
Keyword(s):  
Time Series ◽  
South China Sea ◽  
Water Column ◽  
South China ◽  
Time Series Data ◽  
Northern South China Sea ◽  
Sediment Traps ◽  
Series Data ◽  
Secular Equilibrium ◽  
China Sea

Abstract. Vertical distributions of dissolved and particulate 210Pb and 210Po in the water column at the SouthEast Asian Time-series Study (SEATS, 18°00´ N and 116°00´ E) station in the northern South China Sea were determined from four cruises between January 2007 and June 2008. A large deficiency of 210Pb, 379 ± 43 × 103 dpm m−2, from the secular equilibrium was found within the 3500 m water column. On the other hand, a smaller deficiency of 210Po, 100 ± 21 × 103 dpm m−2, relative to 210Pb was found in the water column. Time-series data showed insignificant temporal variability of the 210Pb and 210Po profiles. To balance these deficiencies, the removal fluxes for 210Pb and 210Po via particle settling ranging from 45 to 51 dpm m−2d−1 and from 481 to 567 dpm m−2d−1, respectively, are expected at 3500 m. The 210Pb removal flux is comparable with, whereas the 210Po removal flux is much higher than, the flux directly measured by moored sediment traps. The discrepancy between the modeled 210Po flux and the measured flux suggests that sporadic events that enhance 210Po removal via sinking ballast may occur in the water column at the site.

scholarly journals Seasonal distributions and fluxes of <sup>210</sup>Pb and <sup>210</sup>Po in the Northern South China Sea

2014 ◽  
Vol 11 (7) ◽  
pp. 11533-11567
Author(s):  
C.-L. Wei ◽  
M.-C. Yi ◽  
S.-Y. Lin ◽  
L.-S. Wen ◽  
W.-H. Lee
Keyword(s):  
Time Series ◽  
South China Sea ◽  
Water Column ◽  
South China ◽  
Time Series Data ◽  
Northern South China Sea ◽  
Sediment Traps ◽  
Series Data ◽  
Secular Equilibrium ◽  
China Sea

Abstract. Vertical distributions of dissolved and particulate 210Pb and 210Po in the water column at the SouthEast Asian Time-series Study (SEATS, 18°00' N and 116°00' E) station in the northern South China Sea were determined from 4 cruises between January 2007 and June 2008. A large deficiency of 210Pb, 379 ± 43 × 103 dpm m−2, from the secular equilibrium was found within the 3500 m water column. On the other hand, a smaller deficiency of 210Po, 100 ± 21 × 103 dpm m−2, relative to 210Pb was found in the water column. Time-series data showed insignificant temporal variability of the 210Pb and 210Po profiles. To balance these deficiencies, the removal fluxes for 210Pb and 210Po via particle settling range from 45 to 51 dpm m−2 d−1 and from 481 to 567 dpm m−2 d−1, respectively, are expected at 3500 m. The 210Pb removal flux is comparable with, whereas the 210Po removal flux is much higher than, the flux directly measured by moored sediment traps. The discrepancy between the modeled 210Po flux and the measured flux suggests that sporadic events that enhance 210Po removal via sinking ballast may occur in the water column at the site.

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

2013 ◽  
Vol 10 (10) ◽  
pp. 6419-6432 ◽  
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.

scholarly journals Physical Forcing-Driven Productivity and Sediment Flux to the Deep Basin of Northern South China Sea: A Decadal Time Series Study

2018 ◽  
Vol 10 (4) ◽  
pp. 971 ◽  
Author(s):  
Hon-Kit Lui ◽  
Kuang-Yu Chen ◽  
Chen-Tung Chen ◽  
Bo-Shian Wang ◽  
Hui-Ling Lin ◽  
...  
Keyword(s):  
Time Series ◽  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Sediment Flux ◽  
Deep Basin ◽  
Time Series Study ◽  
China Sea ◽  
Physical Forcing ◽  
Series Study

scholarly journals Anthropogenic 129I in the South China Sea and coastal waters around Taiwan

Elem Sci Anth ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
George S. Burr ◽  
Hiroyuki Matsuzaki ◽  
Bo-Shian Wang ◽  
Haruka Kusuno ◽  
Hironori Tokuyama ◽  
...  
Keyword(s):  
Time Series ◽  
South China Sea ◽  
South China ◽  
Time Series Data ◽  
The South China Sea ◽  
Series Data ◽  
Northwest Coast ◽  
The South ◽  
Surface Ocean ◽  
The Kuroshio

In this article, we present a study of seawater 129I/127I time-series data from several coastal sites in Taiwan, including Yehliu Geopark (north–northeast coast), Kaohsiung (southwest coast), and Zhuwei Fishing Village (northwest coast). The objective of this study was to document how 129I/127I responds to known seasonal variations in the surface ocean currents that carry 129I to each of these sites. The responses were shown to be quite distinct. The Zhuwei site, across Mainland China, had elevated spring and summer 129I/127I values, with abrupt peaks that reflected transient cross-strait currents that carry seawater with elevated 129I to the northwest coast of Taiwan. The Yehliu site, which receives all of its seawater from the Kuroshio Current, had relatively low and uniform 129I/127I values year-round. The Kaohsiung site showed a summertime minimum that likely stems from upwelling upstream induced by oceanic eddies associated with the Kuroshio intrusion. To our knowledge, these are the first continuous coastal 129I/127I time-series data published for Asian waters and the first to show large, abrupt, and regional 129I/127I changes in the surface seawater. We also documented 129I/127I values from multiple surface ocean sites in the South China Sea (SCS), including a vertical profile from the South East Asia Time-Series Station that extends to a depth of 3,700 m. The 129I from both coastal Taiwan and surface waters of the SCS is &gt;98% anthropogenic, primarily released to the environment as a byproduct of nuclear fuel reprocessing.

scholarly journals Asian Winter Monsoon Imprint on the Water Column Structure at the Northern South China Sea Coast

2021 ◽  
Vol 9 ◽  
Author(s):  
Yancheng Zhang ◽  
Kai Zhu ◽  
Chao Huang ◽  
Deming Kong ◽  
Yuxin He ◽  
...  
Keyword(s):  
South China Sea ◽  
Water Column ◽  
South China ◽  
Northern South China Sea ◽  
Critical Factor ◽  
Ice Age ◽  
Physical Parameters ◽  
Monsoon Circulation ◽  
China Sea ◽  
Effective Manner

Coastal regions of the northern South China Sea (SCS) strongly interact with the Asian monsoon circulation (AMC). Thus, variations of sea surface temperature (SST) here are newly suggested to document AMC changes in an effective manner, but additional physical parameters of oceanic conditions, probably also in relation to the AMC system, remain poorly understood. In this study, we analyzed glycerol dialkyl glycerol tetraethers (GDGTs) from a well-dated sediment core YJ, retrieved at the northern SCS coast, to further scrutinize the intrinsic response of water column to winter AMC strength. It shows that within the time frame of past ∼1,000 years, the tetraether index of lipids with 86 carbon atoms (TEX86) and published alkenone (U37K′) temperature records together confirm a reduced thermal gradient during the Little Ice Age (LIA), in comparison to that during the Medieval Climate Anomaly (MCA). Considering concurrent variations of the branched and isoprenoid tetraether (BIT) and the ratio of archaeol to caldarchaeol (ACE), for example, with decreased values (&lt;∼0.3) for the former and relatively high values for the latter at the LIA, indicative of stratification and salinity changes, respectively, these multiple lines of evidence thereby call for well mixing of onsite water at site YJ correspondingly. Our results suggest that winter AMC strength is a critical factor for mixing subsurface waters and modifying thermal/saline conditions at the northern SCS coasts through the last millennium and also, perhaps, on longer timescales.

Depth distributions of alkalinity, TCO2 and at SEATS time-series site in the northern South China Sea

2007 ◽  
Vol 54 (14-15) ◽  
pp. 1469-1485 ◽  
Author(s):  
W.C. Chou ◽  
D.D. Sheu ◽  
B.S. Lee ◽  
C.M. Tseng ◽  
C.T.A. Chen ◽  
...  
Keyword(s):  
Time Series ◽  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
China Sea ◽  
Depth Distributions

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

2013 ◽  
Vol 10 (4) ◽  
pp. 6939-6972 ◽  
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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