Analysis Of Marine Benthic Annelid Diversity In Nanji Islands Based On High-throughput DNA Sequencing

China established the Marine Nature Reserve System in 1990.Among them,Nanjian Islands National Marine Nature Reserve is one of the five marine nature reserves initially established,and is also the first nature reserve for island and sea area ecosystem established by China.Since the establishment of the reserve,a number of background surveys of ecological resources have been conducted.Nanjian Islands National Marine Nature Reserve is now not only a protected area for the protection of shellfish and algae,but also a protected area for all species on and around the island.Relative to bermines,research on macrobenthic organisms in protected areas is relatively scarce.Therefore,this paper adopts an annual sample collection of large macrobenthos to preliminarily study Nanjian Islands National Marine Nature Reserve.The species diversity composition of macrozoobenthos was studied.With biologists increasingly studying taxonomy,traditional morphological methods can no longer meet the need for species identification,especially for species with similar morphological characteristics.The rapid development of molecular biology has provided biologists with a new method of species classification,using DNA barcodes for species identification.In recent years,with the development of biotechnology,the cost of sequencing has become less and less,which also greatly promotes the application of molecular biology in species identification.At the same time,with the rapid development of second-generation sequencing technologies(ie,high-throughput sequencing technologies),there are more and more methods for the study of biodiversity.This paper uses both morphological features and DNA barcoding techniques.Identification of macrobenthic animals in the Nanji Islands National Marine Nature Reserve,where DNA barcoding sequencing methods include the first-generation sequencing technology and the second-generation sequencing technology(ie,high-throughput sequencing technology).This article is based on sample collections at the sampling sites set up in the Nanji Islands National Marine Reserve in May(Spring),August(Summer),November(Autumn)2017 and March(Winter)2018.Individuals who obtained macrobenthos were sampled on a quarterly basis and used a new high-throughput sequencing method.Both the morphological identification and the first-generation sequencing technology using CO I genes as barcodes were identified.There are 30 species of benthic animals.Among them,15 species were identified by high-throughput sequencing,and 21 species were identified by morphological and sanger sequencing.At the same time,macrobenthos biodiversity was obtained every season in the Nanji Islands National Marine Reserve,and it was found that the biodiversity remained stable at a relatively high level,indicating that the establishment of the Nanji Islands Reserve has played an important role in the protection of natural resources.At the same time,this research also provides reference for the maintenance and planning of biodiversity in future protected areas.Because macrofauna are at the bottom of the food chain,they also provide references and recommendations for fish farming and other aspects of agriculture.