scholarly journals Population subdivision of the surf clamMactra chinensisin the East China Sea: Changjiang River outflow is not the sole driver

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1240 ◽  
Author(s):  
Gang Ni ◽  
Qi Li ◽  
Lehai Ni ◽  
Lingfeng Kong ◽  
Hong Yu
Keyword(s):  
East China Sea ◽  
Environmental Gradient ◽  
East China ◽  
Population Subdivision ◽  
Northwestern Pacific ◽  
Changjiang River ◽  
The East China Sea ◽  
Surf Clam ◽  
China Sea ◽  
River Outflow

The northwestern Pacific, characterized by unique tectonic and hydrological settings, has greatly intrigued marine phylogeographers. However, current studies mostly focus on the influence of Pleistocene isolation of sea basins in population structure of species in the region, leaving the contribution of other factors (such as freshwater outflow and environmental gradients) largely unexploited. Here we shed light on the question by investigating phylogeography of the surf clamMactra chinensisin the East China Sea (ECS). Genetic information was acquired from 501 specimens collected from its main distribution in the region, represented by mitochondrial cytochrome oxidase I (COI) and nine polymorphic microsatellite loci. A shallow and star-like phylogeny was revealed for all COI haplotypes, indicating the origin of populations from a single refugium. Although no divergent lineages existed, population subdivision was detected in both data sets. The most striking pattern was the significant differentiation between populations north and south of a biogeographic boundary—the Changjiang Estuary, suggesting a barrier effect of the freshwater outflow to gene flow. For the northern group, substructure was revealed by COI result as one southernmost population was significant different from other ones. Clear latitude gradations in allele frequencies were revealed by microsatellite analyses, likely influenced by environmental gradient factors such as temperature. Our results demonstrate that genetic subdivision can arise for populations within the ECS despite they have a single origin, and multiple mechanisms including Changjiang River outflow, environmental gradient factors and life-history traits may act in combination in the process.

scholarly journals The large variation in organic carbon consumption in spring in the East China Sea

2013 ◽  
Vol 10 (5) ◽  
pp. 2931-2943 ◽  
Author(s):  
C.-C. Chen ◽  
G.-C. Gong ◽  
F.-K. Shiah ◽  
W.-C. Chou ◽  
C.-C. Hung
Keyword(s):  
Low Temperature ◽  
Organic Carbon ◽  
East China Sea ◽  
Phytoplankton Growth ◽  
East China ◽  
Changjiang River ◽  
Carbon Consumption ◽  
The East China Sea ◽  
China Sea ◽  
The Changjiang River

Abstract. A tremendous amount of organic carbon respired by plankton communities has been found in summer in the East China Sea (ECS), and this rate has been significantly correlated with fluvial discharge from the Changjiang River. However, respiration data has rarely been collected in other seasons. To evaluate and reveal the potential controlling mechanism of organic carbon consumption in spring in the ECS, two cruises covering almost the entire ECS shelf were conducted in the spring of 2009 and 2010. These results showed that although the fluvial discharge rates were comparable to the high riverine flow in summer, the plankton community respiration (CR) varied widely between the two springs. In 2009, the level of CR was double that of 2010, with mean (± SD) values of 111.7 (±76.3) and 50.7 (±62.9) mg C m−3 d−1, respectively. The CR was positively correlated with concentrations of particulate organic carbon and/or chlorophyll a (Chl a) in 2009 (all p < 0.01). These results suggest that the high CR rate in 2009 can be attributed to high planktonic biomasses. During this period, phytoplankton growth flourished due to allochthonous nutrients discharged from the Changjiang River. Furthermore, higher phytoplankton growth led to the absorption of an enormous amount of fugacity of CO2 (fCO2) in the surface waters, even with a significant amount of inorganic carbon regenerated via CR. In 2010, even more riverine runoff nutrients were measured in the ECS than in 2009. Surprisingly, the growth of phytoplankton in 2010 was not stimulated by enriched nutrients, and its growth was likely limited by low water temperature and/or low light intensity. Low temperature might also suppress planktonic metabolism, which could explain why the CR was lower in 2010. During this period, lower surface water fCO2 may have been driven mainly by physical process(es). To conclude, these results indicate that high organic carbon consumption (i.e. CR) in the spring of 2009 could be attributed to high planktonic biomasses, and the lower CR rate during the cold spring of 2010 might be likely limited by low temperature in the ECS. This further suggests that the high inter-annual variability of organic carbon consumption needs to be kept in mind when budgeting the annual carbon balance.

scholarly journals The large variation in organic carbon consumption in spring in the East China Sea

2012 ◽  
Vol 9 (11) ◽  
pp. 16533-16564
Author(s):  
C.-C. Chen ◽  
G.-C. Gong ◽  
F.-K. Shiah ◽  
W.-C. Chou ◽  
C.-C. Hung
Keyword(s):  
Organic Carbon ◽  
East China Sea ◽  
Phytoplankton Growth ◽  
East China ◽  
Community Respiration ◽  
Changjiang River ◽  
Carbon Consumption ◽  
The East China Sea ◽  
China Sea ◽  
The Changjiang River

Abstract. A tremendous amount of organic carbon respired by planktonic communities has been found in summer in the East China Sea (ECS), and this rate has been significantly correlated with fluvial discharge from the Changjiang River. However, data related to this issue in other seasons have rarely been collected. To evaluate and reveal the potential controlling mechanism of organic carbon consumption in spring in the ECS, research using stations covering almost the entire ECS shelf was conducted in the spring of 2009 and 2010. During both periods, the fluvial discharges were similar, and these rates were comparable to high riverine flow in summer. Interestingly, planktonic community respiration (CR) varied widely in both springs; in 2009, the level of CR was double that of 2010, with mean (± SD) values of 111.7 (± 76.3) and 50.7 (± 62.9) mg C m−3 d−1, respectively. The CR was positively linearly regressed with concentrations of particulate organic carbon and/or chlorophyll a (Chl a) in 2009 (all p< 0.01). These results suggest that the rate was dependent on planktonic activities, especially that of phytoplankton, in 2009. During this period, phytoplankton growth flourished due to allochthonous nutrients discharged from the Changjiang River. Furthermore, higher phytoplankton growth leaded to the absorption of an enormous amount of fugacity of CO2 (fCO2) in the surface waters, even with a significant amount of inorganic carbon regenerated via CR. In 2010, there were even more riverine runoff nutrients into the ECS than in 2009. Surprisingly, the growth of phytoplankton in 2010 was not stimulated by enriched nutrients, and its growth was likely limited by low water temperature and/or low light intensity. Low temperature might also suppress planktonic metabolism, and this could explain why the CR was lower in 2010. During this period, lower surface water fCO2 might have mainly been driven by physical process(es). To conclude, these results indicate that organic carbon consumption (i.e. CR) in the ECS in spring might be controlled by the magnitude of planktonic activities and physical factor (e.g. temperature), and that the latter is especially important during a cold spring season. This further suggests that the high intraseasonal variability of organic carbon consumption needs to be kept in mind when budgeting the annual carbon balance.

Influence of the Changjiang River Flood on Synechococcus Ecology in the Surface Waters of the East China Sea

2013 ◽  
Vol 67 (2) ◽  
pp. 273-285 ◽  
Author(s):  
Chih-Ching Chung ◽  
Chin-Yi Huang ◽  
Gwo-Ching Gong ◽  
Yun-Chi Lin
Keyword(s):  
East China Sea ◽  
Surface Waters ◽  
East China ◽  
Changjiang River ◽  
The East China Sea ◽  
China Sea ◽  
The Changjiang River ◽  
River Flood

scholarly journals Observations of flow variability through the Kerama Gap between the East China Sea and the Northwestern Pacific

2014 ◽  
Vol 119 (2) ◽  
pp. 689-703 ◽  
Author(s):  
Hanna Na ◽  
Mark Wimbush ◽  
Jae-Hun Park ◽  
Hirohiko Nakamura ◽  
Ayako Nishina
Keyword(s):  
East China Sea ◽  
East China ◽  
Northwestern Pacific ◽  
The East China Sea ◽  
Flow Variability ◽  
China Sea ◽  
Kerama Gap

Changes in the Synechococcus Assemblage Composition at the Surface of the East China Sea Due to Flooding of the Changjiang River

2015 ◽  
Vol 70 (3) ◽  
pp. 677-688 ◽  
Author(s):  
Chih-Ching Chung ◽  
Gwo-Ching Gong ◽  
Chin-Yi Huang ◽  
Jer-Young Lin ◽  
Yun-Chi Lin
Keyword(s):  
East China Sea ◽  
East China ◽  
Changjiang River ◽  
The East China Sea ◽  
Assemblage Composition ◽  
China Sea ◽  
The Changjiang River
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