Application of DNA metabarcoding to characterize the diet of the moon jellyfish Aurelia coerulea polyps and ephyrae

Dietary studies of polyps and ephyrae are important to understand the formation and magnitude of jellyfish blooms and provide important insights into the marine food web.However,the diet of polyps and ephyrae in situ is largely unknown.Here,prey species of the polyps and ephyrae of the moon jellyfish Aurelia coerulea in situ were identified using high-throughput DNA sequencing techniques.The results show that A.coerulea polyps and ephyrae consume a variety of prey items.The polyps consume both planktonic and benthic prey,including hydromedusae,copepods,ciliates,polychaetes,stauromedusae,and phytoplankton.A.coerulea ephyrae mainly feed on copepods and hydromedusae.Gelatinous zooplankton,including Rathkea octopunctata and Sarsia tubulosa,were frequently found as part of the diet of A.coerulea polyps and ephyrae.The utilization of highthroughput sequencing technique is a useful tool for studying the diet of polyps and ephyrae in the field,complementing the traditional techniques towards a better understanding of the complex role of gelatinous animals in marine ecosystems.

Bacterial communities associated with hydromedusa Gonionemus vertens in diff erent regions in Chinese coastal waters

Bacteria communities in cnidarian jellyfi sh can be harmful to many important aquaculture species,as they can be key vectors of bacterial pathogens.However,our knowledge of bacterial communities associated with jellyfi sh in culture ponds and their potential roles in the regulation of aquaculture species remains unclear.In this study,sequencing based on the bacterial 16S rRNA gene was used to investigate the composition and variation of the bacterial communities associated with hydromedusa Gonionemus vertens in sea cucumber culture ponds and natural marine environment.The associated bacterial communities of G.vertens from the culture ponds in the Yellow Sea and Bohai Sea had signifi cantly diff erent compositions,when compared with those from ambient seawater environment.Furthermore,bacterial communities associated with G.vertens had similar diversity and composition in culture ponds and natural marine environment in the Yellow Sea.There were 31 unique bacterial biomarkers identifi ed in three locations.The major communities were highly abundant in Kiloniellales,Octadecabacter,Polynucleobacter,and Polaribacter,and are related to the environmental information processing.Pathogen candidates such as Vibrionales and Chlamydiales had notably low relative abundances(<1%).The venom of the jellyfi sh was considered responsible for damage to the aquaculture.This study provides important data to help assess the impact of cnidarians-associated bacterial communities on pond aquaculture and the infl uences on material cycling and energy fl ow in marine ecosystems.

An electromechanically reconfigurable intelligent surface for enhancing sub-6G wireless communication signal

Reconfigurable intelligent surface(RIS)is emerged as a promising technique to solve the challenges faced by future wireless communication networks.Although the most commonly used electrically-controlled RISs can achieve millisecond-scale speed of dynamic switch,they have a large number of microwave circuit elements(such as PIN diodes or varactors)which will bring non-negligible insertion loss,and the complicity of the bias network to electrically addressing each element will increase with the expansion of the RIS aperture.Aiming at further reducing the fabrication cost and power consumption,herein an electromechanical RIS used for sub-6G wireless communication is proposed.The electromechanical RIS is designed with a passive metasurface and step-motor driver modules,providing simultaneous high-efficiency reflection(over 80%)and continuous reflection phase coverage of 360.Through electromechanical control,the RIS system can realize different reflective wavefront shaping,and has been employed in the indoor sub-6G wireless environment demonstrating a maximum signal improvement of 8.3 dB.The proposed electromechanical RIS is particularly useful for wireless signal enhancement in static blind area,and has the obvious advantage of not requiring continuous power supply after the RIS being regulated.Therefore,it greatly reduces the overall cost and power consumption which may have potentials in indoor application scenarios for improving wireless communication performance.

海水化学需氧量的分析方法与监测技术

化学需氧量(COD)是反映有机污染程度的综合性指标,随着污染的加重及污染物排放总量控制的实施,COD的检/监测变得尤为重要.然而,海水中COD分析测试方法的研究与技术更新进展缓慢,可用仪器设备相对较少,开发可靠、稳定、高效的COD检测新技术及在线、原位、便携分析仪器已成为海洋分析领域中迫切需要解决的重要课题及发展趋势.本文对近年来新兴的COD检测分析方法、分析技术的原理、优缺点进行了论述与总结,分析了各类技术在海水中COD检/监测研究的主要进展与瓶颈,最后,对海水COD检测分析新思路与仪器研制发展方向做出了展望,以期为未来海水中COD的方法研究及在线监测提供参考.