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Causations of phylogeographic barrier of some rocky shore species along the Chinese coastline.

Wang J, Tsang LM, Dong YW - BMC Evol. Biol. (2015)

Bottom Line: Life history traits of individual species will determine the differential responses to these physical factors, and hence resulting in contrasting phylogeography across the same biogeographic barrier.It is concluded that there is a phylogeographical break at the Yangtze River estuary for the rocky shore species and the causation of the barrier is mainly due to the unsuitable substratum and freshwater discharge.Climate change, land reclamation and dam construction, which are changing substrate and hydrological conditions around Yangtze River estuary, will consequently affect the biogeographic pattern of intertidal species.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Marine Environmental Science, College of Marine and Earth Sciences, Xiamen University, Xiamen, China. jieowen8834@gmail.com.

ABSTRACT

Background: Substrate, ocean current and freshwater discharge are recognized as important factors that control the larval dispersal and recruitment of intertidal species. Life history traits of individual species will determine the differential responses to these physical factors, and hence resulting in contrasting phylogeography across the same biogeographic barrier. To determine how these factors affect genetic structure of rocky shore species along the China coast, a comparative phylogeographic study of four intertidal and subtidal species was conducted using mitochondrial and nuclear DNA by combining new sequences from Siphonaria japonica with previously published sequences from three species (Cellana toreuma, Sargassum horneri and Atrina pectinata).

Results: Analysis of molecular variance and pairwise ΦST revealed significant genetic differences between the Yellow Sea (YS) and the other two marginal seas (East China Sea, ECS and South China Sea, SCS) for rocky-shore species (S. japonica, C. toreuma, S. horneri), but not for muddy-shore species Atrina pectinata. Demographic history analysis proved that the population size of all these four species were persistent though the Last Glacial Maximum (LGM, ~20 ka BP). Migration analysis revealed that gene flow differentiated northward and southward migration for these four species. However, the inferred direction of gene flow using alternatively mitochondrial or nuclear markers was contradictory in S. japonica.

Conclusions: It is concluded that there is a phylogeographical break at the Yangtze River estuary for the rocky shore species and the causation of the barrier is mainly due to the unsuitable substratum and freshwater discharge. All four intertidal and subtidal species appear to have persisted through the LGM in China, indicating the lower impact of LGM on intertidal and subtidal species than generally anticipated. The imbalanced gene flow between YS and ESCS groups for these four species could be explained by historical refugia. The discordance between mitochondrial and nuclear markers in the MIGRATE analysis of S. japonica prove the importance of employing multi-locus data in biogeographic study. Climate change, land reclamation and dam construction, which are changing substrate and hydrological conditions around Yangtze River estuary, will consequently affect the biogeographic pattern of intertidal species.

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Maps of the coastal currents and sea surface salinity of the Yangtze River estuary (Insert). a In winter, the China Coastal Current (CCC) flows from north to south along the China coast. b In spring and summer, the (CCC) flows northward into East China Sea (ECS) and turns eastward parallel with the Taiwan Warm Current. 1: China Coastal Current; 2: Yellow Sea Warm Current; 3: Tsushima Warm Current; 4: Kuroshio Current; 5: Taiwan Warm Current; 6: South China Sea Warm Current. Inset: Sea surface salinity of the Yangtze River estuary in winter (a) and summer (b) [30]
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Fig1: Maps of the coastal currents and sea surface salinity of the Yangtze River estuary (Insert). a In winter, the China Coastal Current (CCC) flows from north to south along the China coast. b In spring and summer, the (CCC) flows northward into East China Sea (ECS) and turns eastward parallel with the Taiwan Warm Current. 1: China Coastal Current; 2: Yellow Sea Warm Current; 3: Tsushima Warm Current; 4: Kuroshio Current; 5: Taiwan Warm Current; 6: South China Sea Warm Current. Inset: Sea surface salinity of the Yangtze River estuary in winter (a) and summer (b) [30]

Mentions: The Yangtze River represents another critical factor in the gene flow of coastal species in China. The Yangtze River, the fifth largest river in the world in terms of volume discharge, brings huge amounts of water (8 ~ 9 × 1011 m3) into the East China Sea annually [25]. When the freshwater discharge reaches its maximum in spring and summer, Yangtze River plume can extend eastward or northeastward to the Jeju Island (126°08′ ~ 126°58′E, 33°08′ ~ 33°60′N) [26, 27], and it can dramatically change surrounding ocean currents [26, 28] and salinity of the upper layer of the Kuroshio Current [29, 30] (Fig. 1). Moreover, sediment discharges from the Yangtze and other nearby rivers have formed the Yangtze River Delta with an area of more than 3 × 104 km2 [31, 32]. The ~600 km long coastline from Lianyungang, Jiangsu Province (34°36′N, 119°13′E) to Shaoxing, Zhejiang Province (30°19′N, 120°46′E) is mainly salt marsh [33]. This together with the Yangtze River discharge is assumed to form a contemporary dispersal barrier for marine species that require a hard substratum (e.g. intertidal rocky shore) or with larvae that cannot tolerant decreased salinity, including the gastropod Cellana toreuma [20], the bivalve Cyclina sinensis [34] and the macroalga Sargassum hemiphyllum [18, 35]. However, studies on other coastal fauna did not detect any genetic split across the Yangtze River [24]. Therefore, more comprehensive study is required to test for the influence of this barrier.Fig. 1


Causations of phylogeographic barrier of some rocky shore species along the Chinese coastline.

Wang J, Tsang LM, Dong YW - BMC Evol. Biol. (2015)

Maps of the coastal currents and sea surface salinity of the Yangtze River estuary (Insert). a In winter, the China Coastal Current (CCC) flows from north to south along the China coast. b In spring and summer, the (CCC) flows northward into East China Sea (ECS) and turns eastward parallel with the Taiwan Warm Current. 1: China Coastal Current; 2: Yellow Sea Warm Current; 3: Tsushima Warm Current; 4: Kuroshio Current; 5: Taiwan Warm Current; 6: South China Sea Warm Current. Inset: Sea surface salinity of the Yangtze River estuary in winter (a) and summer (b) [30]
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4465721&req=5

Fig1: Maps of the coastal currents and sea surface salinity of the Yangtze River estuary (Insert). a In winter, the China Coastal Current (CCC) flows from north to south along the China coast. b In spring and summer, the (CCC) flows northward into East China Sea (ECS) and turns eastward parallel with the Taiwan Warm Current. 1: China Coastal Current; 2: Yellow Sea Warm Current; 3: Tsushima Warm Current; 4: Kuroshio Current; 5: Taiwan Warm Current; 6: South China Sea Warm Current. Inset: Sea surface salinity of the Yangtze River estuary in winter (a) and summer (b) [30]
Mentions: The Yangtze River represents another critical factor in the gene flow of coastal species in China. The Yangtze River, the fifth largest river in the world in terms of volume discharge, brings huge amounts of water (8 ~ 9 × 1011 m3) into the East China Sea annually [25]. When the freshwater discharge reaches its maximum in spring and summer, Yangtze River plume can extend eastward or northeastward to the Jeju Island (126°08′ ~ 126°58′E, 33°08′ ~ 33°60′N) [26, 27], and it can dramatically change surrounding ocean currents [26, 28] and salinity of the upper layer of the Kuroshio Current [29, 30] (Fig. 1). Moreover, sediment discharges from the Yangtze and other nearby rivers have formed the Yangtze River Delta with an area of more than 3 × 104 km2 [31, 32]. The ~600 km long coastline from Lianyungang, Jiangsu Province (34°36′N, 119°13′E) to Shaoxing, Zhejiang Province (30°19′N, 120°46′E) is mainly salt marsh [33]. This together with the Yangtze River discharge is assumed to form a contemporary dispersal barrier for marine species that require a hard substratum (e.g. intertidal rocky shore) or with larvae that cannot tolerant decreased salinity, including the gastropod Cellana toreuma [20], the bivalve Cyclina sinensis [34] and the macroalga Sargassum hemiphyllum [18, 35]. However, studies on other coastal fauna did not detect any genetic split across the Yangtze River [24]. Therefore, more comprehensive study is required to test for the influence of this barrier.Fig. 1

Bottom Line: Life history traits of individual species will determine the differential responses to these physical factors, and hence resulting in contrasting phylogeography across the same biogeographic barrier.It is concluded that there is a phylogeographical break at the Yangtze River estuary for the rocky shore species and the causation of the barrier is mainly due to the unsuitable substratum and freshwater discharge.Climate change, land reclamation and dam construction, which are changing substrate and hydrological conditions around Yangtze River estuary, will consequently affect the biogeographic pattern of intertidal species.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Marine Environmental Science, College of Marine and Earth Sciences, Xiamen University, Xiamen, China. jieowen8834@gmail.com.

ABSTRACT

Background: Substrate, ocean current and freshwater discharge are recognized as important factors that control the larval dispersal and recruitment of intertidal species. Life history traits of individual species will determine the differential responses to these physical factors, and hence resulting in contrasting phylogeography across the same biogeographic barrier. To determine how these factors affect genetic structure of rocky shore species along the China coast, a comparative phylogeographic study of four intertidal and subtidal species was conducted using mitochondrial and nuclear DNA by combining new sequences from Siphonaria japonica with previously published sequences from three species (Cellana toreuma, Sargassum horneri and Atrina pectinata).

Results: Analysis of molecular variance and pairwise ΦST revealed significant genetic differences between the Yellow Sea (YS) and the other two marginal seas (East China Sea, ECS and South China Sea, SCS) for rocky-shore species (S. japonica, C. toreuma, S. horneri), but not for muddy-shore species Atrina pectinata. Demographic history analysis proved that the population size of all these four species were persistent though the Last Glacial Maximum (LGM, ~20 ka BP). Migration analysis revealed that gene flow differentiated northward and southward migration for these four species. However, the inferred direction of gene flow using alternatively mitochondrial or nuclear markers was contradictory in S. japonica.

Conclusions: It is concluded that there is a phylogeographical break at the Yangtze River estuary for the rocky shore species and the causation of the barrier is mainly due to the unsuitable substratum and freshwater discharge. All four intertidal and subtidal species appear to have persisted through the LGM in China, indicating the lower impact of LGM on intertidal and subtidal species than generally anticipated. The imbalanced gene flow between YS and ESCS groups for these four species could be explained by historical refugia. The discordance between mitochondrial and nuclear markers in the MIGRATE analysis of S. japonica prove the importance of employing multi-locus data in biogeographic study. Climate change, land reclamation and dam construction, which are changing substrate and hydrological conditions around Yangtze River estuary, will consequently affect the biogeographic pattern of intertidal species.

Show MeSH
Related in: MedlinePlus