The tug‐of‐war between the West Philippine Sea and South China Sea Tropical Waters and Intermediate Waters in the Okinawa Trough

Chen, Chen‐Tung Arthur; Yeh, Ya-Ting; Yanagi, Tetsuo; Bai, Yan; He, Xianqiang; Huang, Ting-Hsuan

doi:10.1002/2015jc011274

Cited by 5 publications

(5 citation statements)

References 51 publications

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“…These patterns are consistent with variations in temperature, and salinity of Kuroshio seawater from the southern to the middle Okinawa Trough [63,64], suggesting that the physical and chemical influence of the Kuroshio current on hydrothermal plume water from the southern Okinawa Trough to the middle Okinawa Trough is reduced.…”

Section: Variable Major Components In Hydrothermal Plumesupporting

confidence: 69%

Understanding the Compositional Variability of the Major Components of Hydrothermal Plumes in the Okinawa Trough

et al. 2018

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Studies of the major components of hydrothermal plumes in seafloor hydrothermal fields are critical for an improved understanding of biogeochemical cycles and the large-scale distribution of elements in the submarine environment. The composition of major components in hydrothermal plume water column samples from 25 stations has been investigated in the middle and southern Okinawa Trough. The physical and chemical properties of hydrothermal plume water in the Okinawa Trough have been affected by input of the Kuroshio current, and its influence on hydrothermal plume water from the southern Okinawa Trough to the middle Okinawa Trough is reduced. The anomalous layers of seawater in the hydrothermal plume water columns have higher K + , Ca 2+ , Mn 2+ , B 3+ , Ca 2+ /SO 4 2− , and Mn 2+ /Mg 2+ ratios and higher optical anomalies than other layers. The Mg 2+ , SO 4 2− , Mg 2+ /Ca 2+ , and SO 4 2− /Mn 2+ ratios of the anomalous layers are lower than other layers in the hydrothermal plume water columns and are consistent with concentrations in hydrothermal vent fluids in the Okinawa Trough. This suggests that the chemical variations of hydrothermal plumes in the Tangyin hydrothermal field, like other hydrothermal fields, result in the discharge of high K + , Ca 2+ , and B 3+ and low Mg 2+ and SO 4 2− fluid. Furthermore, element ratios (e.g., Sr 2+ /Ca 2+ , Ca 2+ /Cl − ) in hydrothermal plume water columns were found to be similar to those in average seawater, indicating that Sr 2+ /Ca 2+ and Ca 2+ /Cl − ratios of hydrothermal plumes might be useful proxies for chemical properties of seawater. The hydrothermal K + , Ca 2+ , Mn 2+ , and B 3+ flux to seawater in the Okinawa Trough is about 2.62-873, 1.04-326, 1.30-76.4, and 0.293-34.7 × 10 6 kg per year, respectively. The heat flux is about 0.159-1,973 × 10 5 W, which means that roughly 0.0006% of ocean heat is supplied by seafloor hydrothermal plumes in the Okinawa Trough.

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Section: Variable Major Components In Hydrothermal Plumesupporting

confidence: 69%

Understanding the Compositional Variability of the Major Components of Hydrothermal Plumes in the Okinawa Trough

et al. 2018

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“…Indeed, evaporation or precipitation may only contribute a several percentage to the interannual changes in salinity in the nSCS (Nan et al, 2016). In fact, the surface and subsurface WPS seawaters have salinities significantly higher than that of the SCS (Chen et al, 2016). Any intrusion of the WPS seawater would then increase the salinity in the SCS.…”

Section: Intrusion Of Offshore Water Raises Do Of Subsurface Water Inmentioning

confidence: 99%

“…Indeed, the potential temperature (θ) vs. salinity plot provides information on such proportions. We differentiated the WPS and SCS seawaters using θ and salinity, as the WPS and SCS seawaters have distinctive θ and salinity distributions from the surface to the bottom (Chen et al, 2016;Lui et al, 2018). Generally speaking, the surface and subsurface waters of the WPS are notably saltier than that of the SCS.…”

Section: Offshore Seawater Intrusion Increases Do But Reduces Nutrienmentioning

confidence: 99%

“…Namely, in addition to eutrophication, the amount of offshore water intrusion could play a significant role in coastal hypoxia. Moreover, the intrusion patterns in some marginal seas follow that of natural climatic oscillations, such as Pacific Decadal Oscillation (PDO) or El Niño/Southern Oscillation (ENSO) (Wu et al, 2014(Wu et al, , 2017Chen et al, 2016). Generally speaking, the PDO and ENSO refer to periodic variations in the sea surface temperature (SST) of the Pacific Ocean north of 20 • N and in tropical region, respectively (Mantua et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

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Intrusion of Kuroshio Helps to Diminish Coastal Hypoxia in the Coast of Northern South China Sea

et al. 2020

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Since half a century ago, the number and area of dead zones (dissolved oxygen (DO) < 2 mg L −1 or 30% saturation) in the coastal oceans has increased dramatically. As widely recognized, the increased terrestrial nutrient and organic matter inputs are the two main factors causing the eutrophication of many coastal oceans. Here we show with decadal observed time series data from stations off the Pearl River Estuary and in the northern South China Sea (nSCS) that a strong intrusion into the nSCS of the West Philippine Sea (WPS) seawater in the form of Kuroshio branch occurred during the warm phase of the Pacific Decadal Oscillation (PDO) around 2003-2004 and 2015-2016 (also a strong El Niño event). Consequently, the DO concentration increased but NO 3 − and PO 4 3− concentrations decreased in the subsurface layers of the nSCS. The WPS seawater was observed to reach the hypoxic area off the Pearl River Estuary in 2003-2004. Likely, due to the oxygen supply carried by the Kuroshio, little hypoxia developed. Yet, anoxic condition developed in the cold phase of PDO or strong La Niña years with weak Kuroshio intrusions.

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“…The SCS water can be categorized into four distinct water masses: a low-salinity mixing-layer water above 100 m depth, high-salinity subsurface water at 100-350 m with maximum salinity, low-salinity intermediate water at 350-800 m with minimum salinity, and high-salinity deep water below 800 m. While there is a similar vertical division of water masses compared to the North Pacific Ocean, the SCS presents a notable difference in the mixing and subsurface layers. The water in the northwest Pacific Ocean is warmer and saltier than that in the SCS (Zeng et al [6] ), whereas in the intermediate layer, the water in the northwest Pacific Ocean is relatively cooler and fresher (Chen et al [7] ).…”

Section: Introductionmentioning

confidence: 99%

Freshening of the Intermediate Waters in the Northern South China Sea over the Past Six Decades

CHEN,

WANG,

SHU

et al. 2024

JTM

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The properties of salinity in the South China Sea (SCS), a significant marginal sea connecting the Pacific and Indian Oceans, are greatly influenced by the transport of fresh water flux between the two oceans. However, the long-term changes in the intermediate water in the SCS have not been thoroughly studied due to limited data, particularly in relation to its thermodynamic variations. This study utilized reanalysis data products to identify a 60-year trend of freshening in the intermediate waters of the northern South China Sea (NSCS), accompanied by an expansion of low-salinity water. The study also constructed salinity budget terms, including advection and entrainment processes, and conducted an analysis of the salinity budget to understand the impacts of external and internal dynamic processes on the freshening trend of the intermediate water in the NSCS. The analysis revealed that the freshening in the northwest Pacific Ocean and the intensification of intrusion through the Luzon Strait at intermediate levels are the primary drivers of the salinity changes in the NSCS. Additionally, a weakened trend in the intensity of vertical entrainment also contributes to the freshening in the NSCS. This study offers new insights into the understanding of regional deep sea changes in response to variations in both thermodynamics and oceanic dynamic processes.

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The tug‐of‐war between the West Philippine Sea and South China Sea Tropical Waters and Intermediate Waters in the Okinawa Trough

Cited by 5 publications

References 51 publications

Understanding the Compositional Variability of the Major Components of Hydrothermal Plumes in the Okinawa Trough

Understanding the Compositional Variability of the Major Components of Hydrothermal Plumes in the Okinawa Trough

Intrusion of Kuroshio Helps to Diminish Coastal Hypoxia in the Coast of Northern South China Sea

Freshening of the Intermediate Waters in the Northern South China Sea over the Past Six Decades

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