Monsoon-induced upwelling off the Vietnamese coast

Dippner, Joachim W.; Nguyen, Kim Vinh; Hein, Hartmut; Ohde, Thomas; Loick, Natalie

doi:10.1007/s10236-006-0091-0

Cited by 100 publications

(106 citation statements)

References 35 publications

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“…This has been observed in numerous satellite, physical oceanographic, and model simulations (Pohlmann 1987;Kuo et al 2000;Dippner et al 2007;Barthel et al 2009). 14 C measurements from intermediate and deep water in the SCS reported by Broecker et al (1986) are significantly lower, ranging from -106‰ at 420 m to -204‰ at 4170 m. The summer upwelling from Ekman transport is thought to be weak and limited to the upper 100 m of the water column (Dippner et al 2007;Barthel et al 2009). At the same time, wind stress is enhanced in the central SCS.…”

Section: Post-bomb Period 1954 To 1986supporting

confidence: 54%

“…The local bathymetry and stratification of the water column result in Ekman pumping and transport, which are important in the generation of summer upwelling offshore of the Vietnamese coast and of an offshore jet at~12°N further from the coast (Kuo et al 2000;Dippner et al 2007;Hein 2008;Chen et al 2012;Wang et al 2013;Zhang 2014). In the southern SCS, surface water seasonally circulates via the Karimata Strait while some is transported through the Sibutu Passage, returning to the Indian Ocean through the Makassar Strait via the Indonesian Throughflow (ITF) (Gordon et al 2012).…”

Section: Mindoro Straitmentioning

confidence: 99%

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Upwelling of Pacific Intermediate Water in the South China Sea Revealed by Coral Radiocarbon Record

et al. 2016

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ABSTRACT. Annual radiocarbon from a massive Porites lutea coral collected from Hon Tre Island, Vietnam, South China Sea (SCS) was analyzed over a~100-yr-long period from AD 1900 to 1986. The pre-bomb results from 1900-1953 show a steady Δ 14 C value of -54.4 ± 1.8‰ (n = 60). These values are similar to coral records located in the central and southern SCS and from Indonesian waters, but are lower than those from Japan. Following the input of anthropogenic bomb 14 C, our results show a sharp increase in Δ 14 C from 1960, reaching a peak value of 155.3‰ in 1973. The Hon Tre Island post-bomb Δ 14 C values are lower than those of other corals located in the SCS and Japan, but higher compared to those in the Indonesian Seas. This study infers a seasonal input of upwelled water depleted in 14 C from the deeper SCS basin that originates from the tropical Pacific via the Luzon Strait. The bifurcation of the North Equatorial Current feeds the surface and intermediate currents in the SCS and Makassar Strait region. However, unlike the Makassar site, this study's coral Δ 14 C does not receive lower 14 C water from the South Pacific Equatorial Current. The Vietnam record therefore represents a unique oceanographic position, reflecting the seasonal influence of older, deeper SCS waters that upwell periodically in this area and have modified the surface waters locally in this region over the last 100 yr.

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Section: Post-bomb Period 1954 To 1986supporting

confidence: 54%

Section: Mindoro Straitmentioning

confidence: 99%

Upwelling of Pacific Intermediate Water in the South China Sea Revealed by Coral Radiocarbon Record

et al. 2016

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“…Dissolved inorganic nitrogen is replenished in the SCS to subsurface layers in summer during southwest monsoon through updwelling, coinciding with decreased mixed layer depth; however, there is year-to-year variability (Chou et al, 2006;Dippner et al, 2007) fixation appears to be linked to this climatically driven seasonality in hydrodynamics and production in the system. Previously, it was estimated that N 2 fixation provides up to 10% of the total carbon production in the SCS (Voss et al, 2006;Loick et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Diversity and abundance of diazotrophic microorganisms in the South China Sea during intermonsoon

et al. 2008

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The spatial heterogeneity of diversity and abundance of diazotrophs were investigated off the Vietnamese coast in the South China Sea (SCS). The study area extended from the Mekong River plume to the shelf region and beyond to stations extending to 1700 m depth. The SCS diazotroph community, based on nifH gene diversity, had components closely related to sequences from open ocean, estuarine, saltmarsh and microbial mat communities. Rarefaction analysis suggested that by using a 97% similarity operational taxonomic unit definition, the majority of nifH sequence diversity in the samples was covered by the 384 nifH clones obtained. The majority of the nifH sequences recovered fell into two clusters: one comprised of Trichodesmium sequences and the other an a-proteobacterial group. Unicellular cyanobacterial groups A and B, and symbiotic filamentous cyanobacterial diazotrophs were detected sporadically. Trichodesmium was by far the most abundant diazotroph, with up to 6 Â 10 5 nifH gene copies per liter. Quantitative PCR probe-primer sets were designed and used to quantify two proteobacterial groups, revealing abundances up to 10 3 -10 4 nifH gene copies per liter, with the highest abundances in the photic zone. Major components of the clone library were also revealed by a nifH microarray and multidimensional scaling (MDS) analysis. MDS showed that samples from the 410 lm size fraction from 0-to 5-m depths clustered separately from the rest of the samples, primarily due to the abundance of Trichodesmium sequences. The SCS diazotroph community has a relatively low diversity and is a mixture of both estuarine and oceanic fingerprints.

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“…Upwelling in VBUS was confirmed by cruise (Dippner et al, 2006) and remote sensing observations (Kuo et al, 2000).…”

Section: Introduction 25mentioning

confidence: 71%

“…The VBUS upwelling strength is intense, and can result in surface cooling of 3~5 °C and an associated cold filament length of ~500 km . The VBUS is modulated by different climatic variations, such as the El Niño and Southern Oscillation (Dippner et al, 2006;Hein et al, 2013;Xie et al, 2003), the Indian Ocean Dipole (Liu et al, 2012;Xie et al, 2009), and the Madden-Julian Oscillation (Isoguchi and Kawamura, 2006;Liu et al, 45 2012).…”

Section: Introduction 25mentioning

confidence: 99%

Physical Modulation to the Biological Productivity in the Summer Vietnam Upwelling System

Lu¹,

Liao²,

Yan³

et al. 2018

Preprint

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Abstract. Biological productivity in the summer Vietnam boundary upwelling system in the western SouthChina Sea, as in many coastal upwelling systems, is strongly modulated by wind. However, the role of ocean 15 circulation and mesoscale eddies has not been elucidated. Here we show a close spatio-temporal covariability between primary production and kinetic energy. High productivity is associated with high kinetic energy, which accounts for ~15% of the production variability. Results from a physical-biological coupled model reveal that the elevated kinetic energy and intensified circulation can be explained by the separation of the upwelling current system. The separated current forms an eastward jet into the interior South China Sea, 20 and the associated southern gyre traps nutrient and favors productivity. When separation is absent, the model shows weakened circulation and eddy activity, with ~21% less nitrate inventory and ~16% weaker primary productivity.

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Monsoon-induced upwelling off the Vietnamese coast

Abstract: During the southwest monsoon

Cited by 100 publications

References 35 publications

Upwelling of Pacific Intermediate Water in the South China Sea Revealed by Coral Radiocarbon Record

Upwelling of Pacific Intermediate Water in the South China Sea Revealed by Coral Radiocarbon Record

Diversity and abundance of diazotrophic microorganisms in the South China Sea during intermonsoon

Physical Modulation to the Biological Productivity in the Summer Vietnam Upwelling System

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