Outbreaks of large-scale green tides formed by Ulva prolifera in the Yellow Sea(YS)cause heavy ecological damages and huge economic losses.However,the ecological consequences of green tides remain poorly understood due to the lack of knowledge on the settlement region of massive green algae floating in the YS.In this study,we established a method to trace the settlement region of floating green algae,using 28-isofucosterol preserved in sediment as the specific biomarker for green algae.Sterols including 28-isofucosterol in surface sediment samples collected during an investigation in the YS and the Bohai Sea(BS)in August 2015 were analyzed using gas chromatography coupled with a mass spectrometer(GC-MS).Based on the content of 28-isofucosterol in sediment samples,the potential settlement region of loating green algae was identified in the sea area southeast to the Shandong Peninsula around the sampling site H06(122.66°E,36.00°N).This paper presents a first result on the settlement region of floating green algae in the YS for providing a solid basis to elucidate the ecological consequences of green tides in the area. 相似文献
Decapterus maruadsi is a commercially important species in China, but has been heavily exploited in some areas. There is a growing need to develop microsatellites promoting its genetic research for the adequate management of this fishery resources. The recently developed specific-locus amplified fragment sequencing (SLAF-seq) is an efficient and high-resolution method for genome-wide microsatellite markers discovery. In this study, 28 905 microsatellites (mono- to hexa-nucleotide repeats) were identified using SLAF-seq technology, of which di-nucleotide was the most frequent (13 590, 47.02%), followed by mono-nucleotide (8 138, 28.15%), tri-nucleotide (5 727, 19.81%), tetra-nucleotide (1 104, 3.82%), pentanucleotide (234, 0.81%), and hexa-nucleotide (112, 0.39%). One hundred and thirty-two microsatellite loci (di- and tri-nucleotide) were randomly selected for amplification and polymorphism, of which 49 were highly polymorphic and well-resolved. The average number of alleles per locus was 13.63, ranging from 4 to 25, and allele sizes varied between 110 bp and 309 bp. The observed heterozygosity ( Ho ) and expected heterozygosity ( He ) ranged from 0.233 to 1.000 and from 0.374 to 0.959, with mean values of 0.738 and 0.836, respectively. The polymorphism information content (PIC) ranged from 0.341 to 0.941 (mean=0.806). However, 12 loci deviated from Hardy-Weinberg equilibrium. Furthermore, transferability tests were also successful in validating the utility of the developed markers in five phylogenetically related species of family Carangidae. A total of 48 microsatellite markers were successfully cross-amplified in Decapterus macarellus, Decapterus macrosoma, Decapterus kurroides, Trachurus japonicus, and Selaroides leptolepis. The present microsatellites provided the first known set of microsatellite DNA markers for D. maruadsi, D. macarellus, D. kurroides, and D. macrosoma, and would be useful for further population genetic and molecular phylogeny studies as well as help with the fisheries management formulation and implementation of the understudied species.
Journal of Geographical Sciences - In this study, we developed an energy security evaluation model (ESEM) from three dimensions, energy supply-transport security, safety of energy utilization, and... 相似文献
The nonlinear wave forces on vertical cylinders induced by freak wave trains were experimentally investigated. A series of freak wave trains with different wave steepness were modeled in a wave flume. The corresponding wave forces on vertical cylinders of different diameters were measured. The experimental wave forces were also compared with the predicted results based on Morison formula. Particular attentions were paid to the effects of wave steepness on the dimensionless peak forces, asymmetry characteristics of the impact forces and high-frequency force components. Wavelet-based analysis methods were employed in revealing the local energy structures and quadratic phase coupling in the freak wave forces. 相似文献
