Dissolved organic carbon in the South China Sea and its exchange with the Western Pacific Ocean

Author(s):  
Kai Wu ◽  
Minhan Dai ◽  
Junhui Chen ◽  
Feifei Meng ◽  
Xiaolin Li ◽  
...  
Zootaxa ◽  
2012 ◽  
Vol 3513 (1) ◽  
pp. 61 ◽  
Author(s):  
TATSUYA KAGA ◽  
HSUAN-CHING HO

The Indian sillago, Sillago indica McKay, Dutt & Sujatha, 1985, is redescribed on the basis of three paratypes and two newly collected specimens.  The presence of two posterior extensions of the swimbladder instead of one suggests that it belongs to the subgenus Sillago.  Comments on its subgeneric status and comparisons with members of Sillago (Sillago) are provided.  Two specimens collected from Vietnam represent the first record of the species from the South China Sea, western Pacific Ocean.


ZooKeys ◽  
2020 ◽  
Vol 989 ◽  
pp. 1-37
Author(s):  
Yu Xu ◽  
Zifeng Zhan ◽  
Kuidong Xu

Explorations of seamounts in the Western Pacific Ocean and South China Sea resulted in collecting 18 specimens of golden gorgonians. Based on the morphology and the genetic analysis of mtMutS, they are described as one new species, Chrysogorgia carolinensissp. nov., and four known species, including Chrysogorgia dendritica Xu, Zhan & Xu, 2020, Metallogorgia melanotrichos (Wright & Studer, 1889), Metallogorgia macrospina Kükenthal, 1919, and Pseudochrysogorgia bellona Pante & France, 2010. Chrysogorgia carolinensis belongs to the Chrysogorgia “group A, Spiculosae” with rods or spindles distributed in the polyp-body wall and tentacles, and differs from all of its congeners except C. dendritica by the 1/3L branching sequence and amoeba-shaped sclerites at the basal polyp body. The mtMutS sequence of C. carolinensissp. nov. has six deletion mutations compared to those of its congeners, supporting the establishment of the new species. Although no genetic variability was observed between the closely related species C. dendritica and C. abludo Pante & Watling, 2012, the former is different from the latter by the apparently irregular sclerites in the polyp body wall. The two specimens of Metallogorgia melanotrichos match well with the original description except for relatively larger polyps, while the M. macrospina specimens have slightly smaller polyps than the holotype. The juvenile of Metallogorgia has an obvious morphological difference with the adults in the colony shape and branches, but they can be unified by the same polyps and sclerites as well as mitochondrial MutS sequences. Thus, the generic diagnosis of Metallogorgia is slightly extended to include the morphology of juveniles. The morphology of Pseudochrysogorgia bellona Pante & France, 2010, as a new record for the South China Sea, matches well with that of the original description. In the phylogenetic trees, the Chrysogorgia species are separated into two clades, and while Metallogorgia and Pseudochrysogorgia formed a sister clade.


2017 ◽  
Vol 34 (1) ◽  
pp. 153-165 ◽  
Author(s):  
Xiaodong Shang ◽  
Yongfeng Qi ◽  
Guiying Chen ◽  
Changrong Liang ◽  
Rolf G. Lueck ◽  
...  

AbstractMeasurements of turbulence in the deep ocean, particularly close to the bottom, are extremely sparse because of the difficulty and operational risk of obtaining deep profiles near the seafloor. A newly developed expendable instrument—the VMP-X (Vertical Microstructure Profiler–Expendable)—carries two microstructure shear probes to measure the fluctuations of vertical shear into the dissipation range and can profile down to a depth of 6000 m. Data from nine VMP-X profiles in the western Pacific Ocean near 11.6°N over rough topography display bottom-intensified turbulence with dissipation rates increasing by two factors of 10 to 4 W kg−1 within 200 m above the bottom. In contrast, over smooth topography in the southern South China Sea near 11°N, three profiles show that turbulence in the bottom boundary layer increases only slightly, with dissipation rates reaching 1 W kg−1. The eddy diffusivity over rough topography reached to 5 m2 s−1. The average diffusivity over all depths was 0.3 and 0.9 m2 s−1 for the tests in the southern South China Sea and in the western Pacific Ocean, respectively, and these values are much larger than previous estimates of less than ≈0.1 m2 s−1 for the main thermocline.


2020 ◽  
Vol 84 ◽  
pp. 91-103 ◽  
Author(s):  
Y Wei ◽  
D Huang ◽  
G Zhang ◽  
Y Zhao ◽  
J Sun

Marine picophytoplankton are abundant in many oligotrophic oceans, but the known geographical patterns of picophytoplankton are primarily based on small-scale cruises or time-series observations. Here, we conducted a wider survey (5 cruises) in the Bay of Bengal (BOB), South China Sea (SCS) and Western Pacific Ocean (WPO) to better understand the biogeographic variations of picophytoplankton. Prochlorococcus (Pro) were the most abundant picophytoplankton (averaging [1.9-3.6] × 104 cells ml-1) across the 3 seas, while average abundances of Synechococcus (Syn) and picoeukaryotes (PEuks) were generally 1-2 orders of magnitude lower than Pro. Average abundances of total picophytoplankton were similar between the BOB and SCS (4.7 × 104 cells ml-1), but were close to 2-fold less abundant in the WPO (2.5 × 104 cells ml-1). Pro and Syn accounted for a substantial fraction of total picophytoplankton biomass (70-83%) in the 3 contrasting seas, indicating the ecological importance of Pro and Syn as primary producers. Pro were generally abundant in oligotrophic open waters; however, the exceptional presence of Pro near the SCS coast was potentially associated with the Kuroshio intrusion. Syn and PEuk abundances were higher near freshwater-dominated areas, which was likely due to dilution waters. Water temperature and cold eddies were also major drivers responsible for the biogeographic distributions of picophytoplankton. Although Pro, Syn and PEuks showed negative correlations with nutrient concentrations, their maximal abundances in vertical distribution showed positive correlations with the nutricline depth, indicating that nutrient availability plays a 2-faceted role in regulating the biogeographic variation in picophytoplankton.


2016 ◽  
Vol 8 (3) ◽  
pp. 14
Author(s):  
Martin D Mitchell

Since 1945 the South China Sea and the western Pacific has functioned as an uncontested global common patrolled by overwhelming U.S. naval and air power projected from a series of peripheral and over the horizon bases. The dramatic rise of China alters this situation and has transformed the South China Sea into a frontier of control as China seeks to morph this maritime theater into a landward extension of the Chinese coast where it can deploy land-based tactics into an arena previously dominated by maritime power and tactics to secure the South China Sea as a de facto territorial water that serves multiple Chinese strategic interests. Hence, the attempt by a land-based Eurasian power (China) to carve a permanent bridgehead into Spykman’s Eurasian maritime periphery. Against, this trend the United States has countered with President Obama’s Asian Pivot. However, the implementation of the Asian Pivot is limited by several post Cold War developments and certain constraints inherent in the geographic setting of the South China Sea. Beyond the South China Sea, the geographic setting favors the U.S. and its allies. Consequently, American options acting singly or in coalition with other nations, most notably Japan and Australia, remain more flexible and able to serve as a long term counterweight to Chinese force projection capabilities into the western Pacific proper. 


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