Coastal and demersal chondrichthyans(sharks,rays,and skates)are expected to exhibit high levels of genetic differentiation in areas of complex geomorphology.Population genetic studies investigating the extent to which...Coastal and demersal chondrichthyans(sharks,rays,and skates)are expected to exhibit high levels of genetic differentiation in areas of complex geomorphology.Population genetic studies investigating the extent to which demographic history shapes the genetic structure of thesefishes are rare.Here,we combined mitochondrial DNA(Cytb and ND2)and 8 nuclear microsatellite loci from 244 individuals to examine the population genetic structure and demographic history of the 3 Indo-West Pacific species of sharpnose rays(Telatrygon zugei,Telatrygon biasa,and Trygon crozieri).High levels of genetic variation both within and between species were identified.Phylogenetic analysis partitioned haplotypes into 2 lineages supporting divergence of T.zugei from T.crozieri and T.biasa during the Pleistocene.Furthermore,microsatellite-based clustering analyses identified 4 genetic groups(i.e.T.zugei from Japan,T.zugei from coastal China,T.biasa from Gulf of Thailand,and T.crozieri from the Andaman Sea).Measurements of genetic differentiation also support these 4 groups.Additionally,Pleistocene demographic expansions were examined in all genetic groups.The climate oscillations and current hydrologic cycles in the Indo-West Pacific appear to coincide with the hypothesis regarding speciation and the observed demographic history trends of the sharpnose rays.Considering the species group has,until recently,been thought to be one species,these results are critical for defining management units and guiding conservation efforts to preserve stingray biodiversity.展开更多
Systematic investigation on enhancing removal of natural organic matter （NOM） using inorganic polymer flocculant （IPF）, polyaluminum chloride（PACI） and polyacrylamide（PAM） was performed in a typical south-Chin...Systematic investigation on enhancing removal of natural organic matter （NOM） using inorganic polymer flocculant （IPF）, polyaluminum chloride（PACI） and polyacrylamide（PAM） was performed in a typical south-China source water. Enhanced coagulation and applying polymer flocculant-aid were compared through jar tests and pilot tests. Raw water and settled water were characterized and fractionated by resin adsorption. The results show that DOC composes major part of TOC. The DOC distribution keeps relatively stable all around the year with typical high amounts of the hydrophilic matter around 50%. The distribution between HoB, HoA and HoN varies and undergoes fluctuation with the year round. During the summer season, the HoN becomes gradually the major part in hydrophobic parts. PACI with the species being tailor-made shows little pH effect during coagulation. The enhanced coagulation dosage for PACI could be 4.5 mg/L for the typical source water. The highest TOC removal achieved 31%. To be economically, 3 mg/L dose is the optimum dosage. Although hydrophilic fractions of NOM of both treatment strategies are removed about 30%, NOM causing UV254 absorbance were well removed（about 90%）. Hydrophobic bases and acids fractions are much more removed under enhanced conditions. The hydrophilic fraction could be better removed using PAM, the polymer coagulant aid.展开更多
基金financially supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA19050202)the Natural Science Found of China(No.31272287 and No.41666008)+1 种基金the Grants-inaid for Conservation of Fishery Resources of the Ministry of Agriculture in China(No.171721301354052003)the JSPS Invitation Fellowship Program for sampling and Research in Japan.
文摘Coastal and demersal chondrichthyans(sharks,rays,and skates)are expected to exhibit high levels of genetic differentiation in areas of complex geomorphology.Population genetic studies investigating the extent to which demographic history shapes the genetic structure of thesefishes are rare.Here,we combined mitochondrial DNA(Cytb and ND2)and 8 nuclear microsatellite loci from 244 individuals to examine the population genetic structure and demographic history of the 3 Indo-West Pacific species of sharpnose rays(Telatrygon zugei,Telatrygon biasa,and Trygon crozieri).High levels of genetic variation both within and between species were identified.Phylogenetic analysis partitioned haplotypes into 2 lineages supporting divergence of T.zugei from T.crozieri and T.biasa during the Pleistocene.Furthermore,microsatellite-based clustering analyses identified 4 genetic groups(i.e.T.zugei from Japan,T.zugei from coastal China,T.biasa from Gulf of Thailand,and T.crozieri from the Andaman Sea).Measurements of genetic differentiation also support these 4 groups.Additionally,Pleistocene demographic expansions were examined in all genetic groups.The climate oscillations and current hydrologic cycles in the Indo-West Pacific appear to coincide with the hypothesis regarding speciation and the observed demographic history trends of the sharpnose rays.Considering the species group has,until recently,been thought to be one species,these results are critical for defining management units and guiding conservation efforts to preserve stingray biodiversity.
文摘Systematic investigation on enhancing removal of natural organic matter （NOM） using inorganic polymer flocculant （IPF）, polyaluminum chloride（PACI） and polyacrylamide（PAM） was performed in a typical south-China source water. Enhanced coagulation and applying polymer flocculant-aid were compared through jar tests and pilot tests. Raw water and settled water were characterized and fractionated by resin adsorption. The results show that DOC composes major part of TOC. The DOC distribution keeps relatively stable all around the year with typical high amounts of the hydrophilic matter around 50%. The distribution between HoB, HoA and HoN varies and undergoes fluctuation with the year round. During the summer season, the HoN becomes gradually the major part in hydrophobic parts. PACI with the species being tailor-made shows little pH effect during coagulation. The enhanced coagulation dosage for PACI could be 4.5 mg/L for the typical source water. The highest TOC removal achieved 31%. To be economically, 3 mg/L dose is the optimum dosage. Although hydrophilic fractions of NOM of both treatment strategies are removed about 30%, NOM causing UV254 absorbance were well removed（about 90%）. Hydrophobic bases and acids fractions are much more removed under enhanced conditions. The hydrophilic fraction could be better removed using PAM, the polymer coagulant aid.
