scholarly journals A barrier to gene flow in the Asian paddle crab, Charybdis japonica, in the Yellow Sea

2015 ◽  
Vol 72 (5) ◽  
pp. 1440-1448 ◽  
Author(s):  
Zhiqiang Han ◽  
Wei Zheng ◽  
Wenbin Zhu ◽  
Cungen Yu ◽  
Bonian Shui ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Yellow Sea ◽  
Population Expansion ◽  
The Yellow Sea ◽  
Northwestern Pacific ◽  
Factors Affecting ◽  
Haizhou Bay ◽  
Coastal Species ◽  
Charybdis Japonica

Abstract Three primary factors affecting genetic patterns of marine species in the Northwestern Pacific Ocean have been proposed: isolation and population expansion during Pleistocene glacial cycles, ocean currents facilitating the gene flow, and the Yangtze River outflow imposing a physical barrier to gene flow. Here, we examined these factors affecting population structuring of the Asian paddle crab, Charybdis japonica, in the Yellow Sea, East China Sea, and adjacent areas. Genetic variation in nine populations of C. japonica (n = 169) was determined from partial mitochondrial cytochrome c oxidase subunit I sequences. Among the 14 haplotypes identified, a dominant haplotype H1 was present in all populations, and a relatively abundant localized haplotype H2 was found in four of the northern populations. Furthermore, the frequency of the common haplotype H1 decreased from south to north. A genetic discontinuity was detected in Haizhou Bay, which divided species into two groups (north group and south group). The lack of genetic structure in the south and north groups indicates high dispersal of C. japonica within groups. Local marine gyres in Haizhou Bay might be responsible for the divergence of the north and south groups. Our study highlights the importance of local marine gyres for influencing genetic structure in marine coastal species in the Northwestern Pacific, especially in species spawning inshore.

scholarly journals Characterization of Bacterial Communities in Bioaerosols over Northern Chinese Marginal Seas and the Northwestern Pacific Ocean in Spring

2019 ◽  
Vol 58 (4) ◽  
pp. 903-917 ◽  
Author(s):  
Manman Ma ◽  
Yu Zhen ◽  
Tiezhu Mi
Keyword(s):  
Pacific Ocean ◽  
Yellow Sea ◽  
Bacterial Communities ◽  
Bohai Sea ◽  
The Yellow Sea ◽  
Northwestern Pacific ◽  
Particle Sizes ◽  
Marine Aerosols ◽  
Northwestern Pacific Ocean ◽  
The Bohai Sea

AbstractStudies of the community structures of bacteria in marine aerosols of different particle sizes have not been reported. Aerosol samples were collected using a six-stage bioaerosol sampler over the Bohai Sea, the Yellow Sea, and northwestern Pacific Ocean in the spring of 2014. The diversity and composition of these samples were investigated by Illumina high-throughput sequencing, and 130 genera were detected in all of the samples; the most abundant bacterial genus was Bacteroides, followed by Prevotella and Megamonas. The Chao1 and Shannon diversity indices ranged from 193 to 1044 and from 5.44 to 8.33, respectively. The bacterial community structure in coarse particles (diameter larger than 2.1 μm) was more complex and diverse than that in fine particles (diameter less than 2.1 μm) in marine bioaerosols from over the Yellow Sea and northwestern Pacific Ocean, while the opposite trend was observed for samples collected over the Bohai Sea. Although we were sampling over marine regions, the sources of the bioaerosols were mostly continental. Temperature and wind speed significantly influenced the bacterial communities in marine aerosols of different particle sizes. There may be a bacterial background in the atmosphere in the form of several dominant taxa, and the bacterial communities are likely mixed constantly during transmission.

scholarly journals Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

2015 ◽  
Vol 15 (18) ◽  
pp. 10905-10924 ◽  
Author(s):  
Y. Zhao ◽  
L. Zhang ◽  
Y. Pan ◽  
Y. Wang ◽  
F. Paulot ◽  
...  
Keyword(s):  
South China Sea ◽  
Nitrogen Deposition ◽  
South China ◽  
Yellow Sea ◽  
The South China Sea ◽  
The Yellow Sea ◽  
Northwestern Pacific ◽  
Atmospheric Nitrogen Deposition ◽  
Atmospheric Nitrogen ◽  
China Sea

Abstract. Rapid Asian industrialization has led to increased downwind atmospheric nitrogen deposition threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2° × 2/3° horizontal resolution over East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a−1 as NH3 and 15.7 Tg N a−1 as NOx. China has the largest sources with 12.8 Tg N a−1 as NH3 and 7.9 Tg N a−1 as NOx; the high-NH3 emissions reflect its intensive agricultural activities. We find Asian NH3 emissions are a factor of 3 higher in summer than winter. The model simulation for 2008–2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8–20 kg N ha−1 a−1, decreasing rapidly downwind of the Asian continent. Deposition fluxes average 11.9 kg N ha−1 a−1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha−1 a−1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7 % over the South China Sea, and become important (greater than 30 %) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian monsoon and in nitrogen emissions. The model adjoint further estimates that nitrogen deposition to the Yellow Sea originates from sources over China (92 % contribution) and the Korean peninsula (7 %), and by sectors from fertilizer use (24 %), power plants (22 %), and transportation (18 %). Deposition to the South China Sea shows source contribution from mainland China (66 %), Taiwan (20 %), and the rest (14 %) from the southeast Asian countries and oceanic NH3 emissions. The adjoint analyses also indicate that reducing Asian NH3 emissions would increase NOy dry deposition to the Yellow Sea (28 % offset annually), limiting the effectiveness of NH3 emission controls on reducing nitrogen deposition to the Yellow Sea.

scholarly journals Population genetic structure of the malaria vector Anopheles minimus in Thailand based on mitochondrial DNA markers

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kamonchanok Bunmee ◽  
Urusa Thaenkham ◽  
Naowarat Saralamba ◽  
Alongkot Ponlawat ◽  
Daibin Zhong ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
Malaria Vector ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Haplotype Diversity ◽  
Population Expansion ◽  
Anopheles Minimus ◽  
The Past ◽  
Oxidase Subunit

Abstract Background The malaria vector Anopheles minimus has been influenced by external stresses affecting the survival rate and vectorial capacity of the population. Since An. minimus habitats have continuously undergone ecological changes, this study aimed to determine the population genetic structure and the potential gene flow among the An. minimus populations in Thailand. Methods Anopheles minimus was collected from five malaria transmission areas in Thailand using Centers for Disease Control and Prevention (CDC) light traps. Seventy-nine females from those populations were used as representative samples. The partial mitochondrial cytochrome c oxidase subunit I (COI), cytochrome c oxidase subunit II (COII) and cytochrome b (Cytb) gene sequences were amplified and analyzed to identify species and determine the current population genetic structure. For the past population, we determined the population genetic structure from the 60 deposited COII sequences in GenBank of An. minimus collected from Thailand 20 years ago. Results The current populations of An. minimus were genetically divided into two lineages, A and B. Lineage A has high haplotype diversity under gene flow similar to the population in the past. Neutrality tests suggested population expansion of An. minimus, with the detection of abundant rare mutations in all populations, which tend to arise from negative selection. Conclusions This study revealed that the population genetic structure of An. minimus lineage A was similar between the past and present populations, indicating high adaptability of the species. There was substantial gene flow between the eastern and western An. minimus populations without detection of significant gene flow barriers. Graphical abstract

scholarly journals Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

2015 ◽  
Vol 15 (9) ◽  
pp. 13657-13703 ◽  
Author(s):  
Y. H. Zhao ◽  
L. Zhang ◽  
Y. P. Pan ◽  
Y. S. Wang ◽  
F. Paulot ◽  
...  
Keyword(s):  
South China Sea ◽  
Nitrogen Deposition ◽  
South China ◽  
Yellow Sea ◽  
The South China Sea ◽  
The Yellow Sea ◽  
Northwestern Pacific ◽  
Atmospheric Nitrogen Deposition ◽  
Atmospheric Nitrogen ◽  
China Sea

Abstract. Rapid Asian industrialization has led to increased atmospheric nitrogen deposition downwind threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2° × 2/3° horizontal resolution over the East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a−1 as NH3 and 15.7 Tg N a−1 as NOx. China has the largest sources with 12.8 Tg N a−1 as NH3 and 7.9 Tg N a−1 as NOx; the high NH3 emissions reflect its intensive agricultural activities. We find Asian NH3 emissions are a factor of 3 higher in summer than winter. The model simulation for 2008–2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8–20 kg N ha−1 a−1, decreasing rapidly downwind the Asian continent. Deposition fluxes average 11.9 kg N ha−1 a−1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha−1 a−1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7% over the South China Sea, and become important (greater than 30%) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian Monsoon and in nitrogen emissions. The model adjoint further estimates that nitrogen deposition to the Yellow Sea originates from sources over China (92% contribution) and the Korean peninsula (7%), and by sectors from fertilizer use (24%), power plants (22%), and transportation (18%). Deposition to the South China Sea shows source contribution from Mainland China (66%), Taiwan (20%), and the rest 14% from the Southeast Asian countries and oceanic NH3 emissions. The adjoint analyses also indicate that reducing Asian NH3 emissions would increase NOy dry deposition to the Yellow Sea (28% offset annually), limiting the effectiveness of NH3 emission controls.

scholarly journals Improving size selectivity of round pot for Charybdis japonica by configuring escape vents in the Yellow Sea, China

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12282
Author(s):  
Mengjie Yu ◽  
Liyou Zhang ◽  
Changdong Liu ◽  
Yanli Tang
Keyword(s):  
Sustainable Development ◽  
Coastal Waters ◽  
Yellow Sea ◽  
Comparison Method ◽  
The Yellow Sea ◽  
Size Selectivity ◽  
The Sustainable Development ◽  
Charybdis Japonica ◽  
Yellow Sea Of China ◽  
Escape Vent

Sustainable development of the important economic species, Asian paddle crab (Charybdis japonica), has attracted attention in the coastal waters of the Yellow Sea, China. The commonly used round pots are almost nonselective, resulting in severe bycatch of juveniles. In this study, we explored a method to improve the size selectivity for C. japonica by mounting escape vents on the side panels of each pot. The selectivity of pots with escape vent sizes of 70 mm × 20 mm, 70 mm × 25 mm, 70 mm × 30 mm, and 70 mm × 35 mm was tested using a catch comparison method. The estimated minimum landing size (MLS) of carapace height (27 mm), according to the regulated MLS of carapace length (50 mm), was used as a reference point to explain the results. Significant increases in the size of crabs caught by pots were found with the enlargement of escape vent size (Kruskal–Wallis test, P < 0.01). The pots with 70 mm × 20 mm, 70 mm × 25 mm and 70 mm × 30 mm escape vents released nearly 50%, 75% and 95% of undersized individuals, respectively, and these three types of pots retained approximately 90% of legal-sized individuals compared with the control pots without escape vents. The pots with 70 mm × 35 mm escape vents released nearly all undersized individuals, but they also released most legal-sized individuals. Pots with an escape vent size of 70 mm × 30 mm were recommended for the sustainable development of C. japonica in the Yellow Sea of China. The results of this study reiterate the importance of carapace height for determining the size selectivity, which can serve as a reference to formulate management regulations in the coastal waters of the Yellow Sea, China.

scholarly journals Phylogeographic and population insights of the Asian common toad (Bufo gargarizans) in Korea and China: population isolation and expansions as response to the ice ages

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4044 ◽  
Author(s):  
Amaël Borzée ◽  
Joana L. Santos ◽  
Santiago Sánchez-RamÍrez ◽  
Yoonhyuk Bae ◽  
Kyongman Heo ◽  
...  
Keyword(s):  
Sea Level ◽  
Yellow Sea ◽  
Korean Peninsula ◽  
East Asian ◽  
Population Expansion ◽  
The Yellow Sea ◽  
Ice Ages ◽  
Common Toad ◽  
North East ◽  
Bufo Gargarizans

The effects of ice ages on speciation have been well documented for many European and North American taxa. In contrast, very few studies have addressed the consequences of such environmental and topographical changes in North East Asian species. More precisely, the Korean Peninsula offers a unique model to assess patterns and processes of speciation as it hosts the northern- and eastern-most distribution limit of some widespread Asian taxa. Despite this, studies addressing phylogeographic patterns and population genetics in the peninsula and surrounding countries are few and studies for most families are lacking. Here we inferred the phylogenetic relationships of the common toad (Bufo gargarizans) from South Korea and their North East Asian counterpart populations, based on mitochondrial data. KoreanB. gargarizansGenBank BLASTs matched few individuals from nearby China, but the presence of a Korean clade suggests isolation on the Korean Peninsula, previous to the last glacial maximum, linked to sea level resurgence. Molecular clock calibrations within this group were used to date the divergence between clades and their relationship to paleo-climatic events in the area. Lack of genetic structure among South Korean populations and strong homogeneity between the Korean and some Chinese localities suggest weak isolation and recent expansion. Geographical projection of continuous coalescent maximum-clade-credibility trees shows an original Chinese expansion towards the Korean Peninsula through the Yellow Sea circa two million years ago with colonisation events dating circa 800 thousand years ago (K. y. a.). Following this colonisation, the data point to outgoing Korean Peninsula dispersal events throughout different periods, towards the North through land, and West through land bridge formations over the Yellow Sea during sea level falls. In accordance, demographic analyses revealed a population expansion in the Koran Peninsula circa 300 K. y. a., likely attributed to glacial cycle fluctuations.

The genetic structure of the spectacled bear (Tremarctos ornatus; Ursidae, Carnivora) in Colombia by means of mitochondrial and microsatellite markers

2020 ◽  
Vol 101 (4) ◽  
pp. 1072-1090
Author(s):  
Manuel Ruiz-García ◽  
Jessica Yanina Arias Vásquez ◽  
Héctor Restrepo ◽  
Carlos Herney Cáceres-Martínez ◽  
Joseph Mark Shostell
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Isolation By Distance ◽  
Phylogenetic Analyses ◽  
Population Expansion ◽  
Sudden Expansion ◽  
Population Decrease ◽  
Geographical Regions ◽  
Show Evidence

Abstract The spectacled bear (Ursidae: Tremarctos ornatus) is an emblematic umbrella species and one of the top carnivores in the Andean mountains. It is also listed as vulnerable by IUCN and as endangered by CITES. We analyzed the genetic structure of this species in nine geographical regions representing the three Andean Cordilleras in Colombia. We sequenced six mitochondrial genes in 115 spectacled bears; a subset of these specimens (n = 61) were genotyped at seven nuclear microsatellites. We addressed three objectives: 1) determine the genetic diversity and historical demographic changes of the spectacled bear in Colombia; 2) determine phylogeographic patterns of genetic divergence among spectacled bear populations in Colombia; and 3) estimate the levels of gene flow among different regions of Colombia. Our analyses show evidence of high mitochondrial genetic diversity in spectacled bears, both in Colombia as well as in each of the nine regions, most particularly Norte de Santander, Nariño, and Antioquia-Córdoba. In addition, we detected population expansion in Colombia that occurred around 24,000 years ago, followed by a population decrease during the last 7,000 years, and a sudden expansion in the last 300 years. Phylogenetic analyses showed few well-supported clades, with some haplotypes detected in all the departments and Colombian Andean Cordilleras, and other haplotypes restricted to certain geographical areas (Antioquia, Norte de Santander, Cundinamarca, and Nariño). We detected significant genetic heterogeneity among some departments and among the three Colombian Andean Cordilleras for both mitochondrial and nuclear genes. Nevertheless, the moderate levels of gene flow estimated from FST statistics suggest that geographical barriers have not been definitive obstacles to the dispersion of the spectacled bear throughout Colombia. Despite these gene flow estimates, significant spatial autocorrelation was detected for spectacled bear in Colombia, where two kinds of spatial patterns were discovered: genetic patches of 144 km of diameter, and isolation by distance among bears separated from 578 to 800 km. The two most northern spectacled bear populations of Colombia (Norte de Santander and Antioquia) also were the two most differentiated. Their distinctiveness may qualify them as distinct Management Units (MUs) in the context of conservation policies for the spectacled bear in Colombia.

scholarly journals Development and Validation of an Operational Search and Rescue Modeling System for the Yellow Sea and the East and South China Seas

2014 ◽  
Vol 31 (1) ◽  
pp. 197-215 ◽  
Author(s):  
Kyoung-Ho Cho ◽  
Yan Li ◽  
Hui Wang ◽  
Kwang-Soon Park ◽  
Jin-Yong Choi ◽  
...  
Keyword(s):  
South China ◽  
Yellow Sea ◽  
Search And Rescue ◽  
The Yellow Sea ◽  
Northwestern Pacific ◽  
Model Parameters ◽  
China Seas ◽  
Operational Forecasting ◽  
Sar Model ◽  
Forecasting System

Abstract An operational search and rescue (SAR) modeling system was developed to forecast the tracks of victims or debris from marine accidents in the marginal seas of the northwestern Pacific Ocean. The system is directly linked to a real-time operational forecasting system that provides wind and surface current forecasts for the Yellow Sea and the East and South China Seas and is thus capable of immediately predicting the tracks and area to be searched for up to 72 h in the future. A stochastic trajectory model using a Monte Carlo ensemble technique is employed within the system to estimate the trajectories of drifting objects. It is able to consider leeway drift and to deal with uncertainties in the forcing fields obtained from the operational forecasting system. A circle assessment method was applied to evaluate the performance of the SAR model using comparisons in buoy and ship trajectories obtained from field drifter experiments. The method effectively analyzed the effects of the forcing fields and diagnosed the model’s performance. Results showed that accurate wind and current forcing fields play a significant role in improving the behavior of the SAR model. Operationally, the SAR modeling system is used to support the Korea Coast Guard during marine emergencies. Additionally, some sensitivity tests for model parameters and wave effect on the SAR model prediction are discussed.

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