环境DNA宏条形码在浮游动植物多样性研究中的应用
Application of environmental DNA metabarcoding in studying biodiversity of zooplankton and phytoplankton
通讯作者: 孙翰昌(1978—),男,教授,研究方向为渔业资源评估和生态补偿策略、水产品质量安全检测与评价等。E-mail:sunhanchang199@163.com
收稿日期: 2023-02-17
基金资助: |
|
Received: 2023-02-17
作者简介 About authors
吴泳江(1990—),男,讲师,博士,主要从事动物营养与水产动物生态健康养殖研究。E-mail:wyongjang@163.com
浮游植物和浮游动物分别是水生生态系统的初级生产者和消费者,浮游动植物的准确识别鉴定是开展水生生态学研究的基础。传统的基于物种形态特征鉴定浮游动植物费时费力,鉴定困难,也低估了物种多样性。因此,亟需一套简单、高效、准确、标准化的解决方案,用于浮游动植物多样性研究。环境DNA(Environmental DNA,eDNA)宏条形码技术已成为水生生物多样性研究的常用方法,主要被应用于鱼类物种多样性研究,近年来也逐渐被用于浮游动植物多样性研究中。本文首先介绍了eDNA宏条形码技术及其采样方法,再重点综述该技术在浮游动植物研究中的应用,以推动eDNA宏条形码技术在浮游生物多样性研究上的发展。
关键词:
Phytoplankton and zooplankton are the primary producers and consumers of aquatic ecosystems, respectively. Their accurate identification is the basis for aquatic ecology research. Traditional identification of phytoplankton and zooplankton based on morphological characteristics of species is time-consuming and labor-consuming, difficulty in identification, and underestimating species diversity. Therefore, a simple, efficient, accurate and standardized solution for studying biodiversity of zooplankton and phytoplankton is very necessary. Environmental DNA (eDNA) metabarcoding technique has become a common method for studying aquatic biodiversity. It is mainly used in the studying of fish species diversity and has also been gradually used in the studying biodiversity of zooplankton and phytoplankton in recent years. This review firstly introduced the eDNA metabarcoding technique and its sampling method, and then focused on the application of this technique in the studying of biodiversity of zooplankton and phytoplankton to promote the development of eDNA metabarcoding technique in plankton diversity research.
Keywords:
本文引用格式
吴泳江, 蔡明成, 孙翰昌, 胡慧蝶, 邓雅心, 龙应根.
WU Yongjiang, CAI Mingcheng, SUN Hanchang, HU Huidie, DENG Yaxin, LONG Yinggen.
浮游植物是水生生态系统的初级生产者,其生产力占地球总生产力的一半以上[1]。浮游动物是浮游植物的主要消费者,是连通初级生产者与高营养级动物的关键营养纽带[2]。浮游动植物种类丰富、数量庞大、个体微小、分布广泛,导致基于传统形态学鉴定方法难以准确区分其种类,主要有以下原因:1)对鉴定人员形态学分类知识要求较高,基于主观形态判断难以标准化,且费时、费力;2)浮游动植物的生命周期短,生命周期内形态变化大;3)浮游动植物种间形态特征的趋同进化,导致形态学差异不明显;4)浮游动植物的形态表型存在可塑性,形态区分不精确。而最新的环境DNA(Environmental DNA,eDNA)宏条形码技术针对上述难题提供了一套崭新的解决方案,其无需分离生物个体,仅需提取浮游动植物遗留在水体环境中的DNA,基于特定的条形码基因设计通用引物完成PCR扩增,然后通过高通量测序和数据库序列比对,进行物种注释,最终实现物种多样性评估[3]。因此,本文重点围绕eDNA宏条形码技术在浮游动植物多样性研究中的应用进行综述,旨在为eDNA宏条形码技术的发展提供理论基础资料。
1 eDNA宏条形码技术概述
eDNA是指生物体遗留在环境中的DNA的总和,可直接从环境样品(水体、空气、土壤等)中提取获得,不具备任何明显的生物源[4]。水环境中的DNA,包括生物体经由粪便、皮肤、黏液等路径释放到水体中的DNA,主要为线粒体DNA和核DNA[5],其中利用线粒体DNA分析水生生物多样性的研究[6-7]较多。eDNA在所处环境中会经历衰变、浓度下降、直至无法再被检测的过程[8]。DNA条形码技术由Hebert P D N等[9]于2003年首次提出,是利用不同物种在特定基因序列(条形码)上存在的差异来开展物种鉴别的技术。随着高通量测序技术的快速发展,为能够一次性检测宏量的基因序列并且可高效检测生物多样性,eDNA宏条形码技术应运而生,相较于DNA条形码技术,其优势体现在“宏”字上、以eDNA为基本检测单位[10]。
eDNA宏条形码技术首先要采集和提取eDNA,根据检测目的选择合适的条形码基因来设计通用引物,再利用引物对eDNA进行PCR扩增和高通量测序;其次拼接和合并测序获得的双端测序序列,并过滤掉低质量、嵌合体以及小于150 bp的噪音序列,之后通常根据97%的相似度阈值将序列聚类成可操作分类单元(Operational taxonomic units,OTUs),再进行比对;最后通过生物信息学分析完成物种注释,达到物种鉴定的目的[11]。eDNA宏条形码技术研究浮游动植物具备以下优势:1)无需采集生物样本,对环境破坏少;2)不受物种性别和生理发育阶段的影响;3)能准确区分形态相似和表型可塑性高的物种;4)有统一的条形码数据库,鉴定标准统一,避免受鉴定人员主观经验的影响[2,12]。
2 eDNA宏条形码在浮游动物植物多样性研究中的采集方法
eDNA宏条形码技术研究浮游生物多样性,其采样的关键是尽可能多的采集浮游生物的eDNA。水体中eDNA的分布易受季节、自然环境、人类活动等因素的影响,因此需要依据水体环境特征,使用具有针对性的采样方案。1)溪流、湍急的河水和江水属于流动水体,eDNA混合较为均匀,其采样只需采集表层水[13],通常以主观确定的距离间隔从河岸和沿着水道取样,并在一个采样点采集多个样品。随着水体自上游向下游流动,河口处造就了丰富的物种,因此在河口处采样可以较为全面地整合河流网络的生物多样性信息[14]。2)湖泊、水库、池塘等静止水体,通常采集沿岸表层水即可[15]。但对于大型湖泊,还需进行精细尺度的eDNA采样或深水区采样。3)浮游动植物是海洋食物网的基础[16],但海水中的eDNA较为破碎,且降解比例较高,因而有必要综合采用基于滤网富集样品和水样的eDNA宏条形码技术[2]。仅仅在海岸线或近海海域采样,导致采样空间覆盖高度较低,生成的物种列表不全,因此需要采用覆盖所调查区域的网格抽样设计方法[17]。而且海洋的垂直空间很大,海水深度对浮游动植物的eDNA组成也有很大的影响,采样时最好覆盖全深度范围的eDNA样本。通常情况下每个采样点采集水样1~2 L,如果浮游生物分布范围广或丰度低,则需要加大取样范围和取水量[18-19]。为降低实验误差和提高目标物种检出率,通常要设置至少3个重复。
水样采集后还需要从中收集eDNA,主要采用过滤法、离心法、沉淀法。过滤法指使用抽滤装置和滤膜对水样进行抽滤,使eDNA富集在滤膜上;离心法指使用离心机对水样做离心处理,使eDNA沉降在离心管底部;沉淀法指使用无水乙醇和乙酸钠对水样中的eDNA进行聚集沉淀。使用过滤法可获得最高浓度的eDNA,其次是离心法,最低的是沉淀法[20-21]。此外,可将过滤法、离心法和沉淀法相结合,获得更为丰富的eDNA。为减少污染和降解,可将收集到的eDNA置于95%乙醇中,放入-20 ℃冰箱中保存,并及时完成扩增和宏条形码测序。在eDNA样品采集过程中,要尽量避免采样环境污染而造成的假阳性结果的出现,因而建议使用10%漂白剂清洗采样器械并消毒,采样过程中操作人员要戴好手套和口罩,并设置阴性对照(空白对照),实时监控污染状况;尽量使用无人机械技术进行采样操作,避免人为采样造成的交叉污染。
3 eDNA宏条形码在浮游植物多样性研究中的应用
浮游植物处于水体食物链的最底端,作为浮游动物和部分水体动物的食物[22-23],是水生生态系统能量传递以及物质流动的基础[24⇓-26],具有细胞结构简单、生长周期短、个体微小等典型特点[27-28],因而其种群结构和丰度能敏锐地反映水域生态环境变化情况[29⇓-31]。eDNA宏条形码技术在浮游植物多样性研究中的应用关键在于选择合适的条形码基因,再针对选定的条形码设计通用引物,完成扩增和测序。目前使用较为广泛的是单基因条形码,其来源于核糖体基因、线粒体基因或叶绿体基因。核糖体基因组主要为内转录间隔区(Internal transcribed space,ITS)、18S rRNA、16S rRNA;线粒体基因组主要为细胞色素C氧化酶Ⅰ(Cytochrome oxidase Ⅰ,COⅠ)、细胞色素C氧化酶Ⅲ(Cytochrome oxidase Ⅲ,CO Ⅲ);叶绿体基因组主要为matK、rbcL、atpB;其他条形码基因包括rpoB、trnL、tufA、rpoC1等。张丽娟等[32]、张莉等[33]、刘卫东等[34]、王晨等[35]在使用eDNA宏条形码技术研究我国海洋、江河、湖泊中的浮游植物多样性时均使用的是18S rRNA基因。这是因为该基因的物种覆盖率较高且条形码数据库较为完善,从而被优先用于浮游植物多样性研究。18S rRNA基因又分为V4可变区和V9可变区,它们均被广泛用作目标基因而完成引物设计[32⇓⇓-35]。基于18S rRNA条形码基因设计的通用引物在利用eDNA宏条形码研究浮游植物多样性中的应用示例见表1。为了提高单基因条形码的分辨率,也可将几种条形码基因联合使用,例如多基因条形码rpoC1+rpoB+matK,但与单基因条形码相比,其分析更为复杂。此外,还有超级条形码和特定条形码,这些在浮游植物多样性研究中均具有巨大的潜力[1]。利用eDNA宏条形码技术研究浮游植物多样性的报道较多,张丽娟等[32]评估了eDNA宏条形码监测真核浮游藻类结果的精确性,发现eDNA宏条形码技术能准确监测到滇池和抚仙湖的真核藻类多样性;Malviya S等[40]和王靖淇等[37]采用eDNA宏条形码技术获得的浮游藻类类群数量要远远高于显微镜观测,且发现了很多新物种;郭婷等[41]基于eDNA宏条形码技术快速监测出鄱阳湖中的浮游植物丰富度、均匀度及其空间分布,有效评估了鄱阳湖的生态系统健康状况。eDNA技术具有简便、高效、准确等优势,在浮游植物研究和多样性监测中被广泛应用。
表1 基于18S rRNA条形码基因设计的通用引物在利用eDNA宏条形码研究浮游植物多样性中的应用示例
Tab.1
条形码基因 Barcode genes | 长度/bp Length | 引物序列 Primer sequences | 应用示例 Application examples |
---|---|---|---|
18S rRNA -V9 | 130 | F:TCCCTGCCHTTTGTACACAC | 研究湖泊真核浮游植物[32] |
R:CCTTCYGCAGGTTCACCTAC | |||
18S rRNA -V9 | 130 | F:CCCTGCCHTTTGTACACAC | 探究黄海微型真核浮游植物多样性[33] |
R:CCTTCYGCAGGTTCACCTAC | |||
18S rRNA-V9 | 130 | F:TCCCTGCCHTTTGTACACAC | 研究秦淮河生物多样性[35] |
R:CCTTCYGCAGGTTCACCTAC | |||
18S rRNA-V9 | 130 | F:CCCTGCCHTTTGTACACAC R:CCTTCYGCAGGTTCACCTAC | 研究韩国蟾津江入海口光阳湾生物多样性[36] |
18S rRNA-V4 | 370 | F:GCGGTAATTCCAGCTCCAATA | 筛选出适合研究微型和微微型浮游植物的引物[34] |
R:GATCCCCHWACTTTCGTTCTTGA | |||
18S rRNA-V4 | 500 | F:GGCAAGTCTGGTGCCAG | 研究辽河真核浮游藻类的群落结构特征[37] |
R:GACTACGACGGTATCTRATCRTCTTCG | |||
18S rRNA-V4 | 450 | F:CCAGCASCYGCGGTAATTCC | 研究北冰洋浮游生物多样性[38] |
R:ACTTTCGTTCTTGATYRR | |||
18S rRNA-V4 | 380 | F:CCAGCASCYGCGGTAATTCC | 研究湖泊中微型和超微型真核浮游生物多样性[39] |
R:ACTTTCGTTCTTGATYRA |
注:18S rRNA -V9为核糖体小亚基rRNA基因的V9可变区;18S rRNA -V4为核糖体小亚基rRNA基因的V4可变区。下表同此。
Notes: 18S rRNA -V9 was the V9 variable region of ribosomal small subunit rRNA gene; 18S rRNA -V4 was the V4 variable region of ribosomal small subunit rRNA gene. The same as the following table.
4 eDNA宏条形码在浮游动物多样性研究中的应用
浮游动物以浮游植物为食,是连通水体中的初级生产者(浮游植物)和高营养级动物(鱼、虾、鸟等)的关键营养枢纽[2,42 -43],具有个体微小、生活史短、代谢旺盛、种类繁多、数量庞大、分布范围广等特点,因而对水体环境变化的响应同样十分敏感[44⇓⇓-47],其种群结构和数量是衡量水体生态健康状况重要的依据[48⇓⇓-51]。利用eDNA宏条形码研究浮游动物与研究浮游植物相似,关键之处都在于选择合适的条形码基因,据此设计最佳的PCR扩增通用引物。与研究浮游植物相同,利用eDNA宏条形码研究浮游动物也使用核糖体基因中的ITS、18S rRNA、16S rRNA[2,52 -53],以及线粒体基因中的COⅠ[54-55]。18S rRNA中的V9可变区比较适用于高通量测序平台,可覆盖更多的浮游动物类群,但对物种的分辨率较低,在种水平上较难区分物种[2]。COⅠ的进化率要高于18S rRNA,在物种水平上的分辨率较高,但对更高分类层级的分辨率较低[56]。高旭等[53]比较了18S rRNA-V9、COⅠ、16S rRNA条形码基因的通用引物在利用DNA研究浮游动物多样性中的差异,发现COⅠ条形码的引物更适用,这是因为其检测的物种特异性、物种覆盖度和物种识别敏感性均适中,且检出的浮游动物种群数量高于18S rRNA-V9引物和16S rRNA引物。基于18S rRNA和COⅠ条形码基因设计的通用引物在利用eDNA宏条形码研究浮游动物多样性中的应用示例见表2。孙晶莹等[57]研究表明,基于eDNA宏条形码技术可有效实现对浮游动物的半定量检测,在浮游生物多样性的研究和监测以及生物完整性评估中具有较大的实际应用价值。唐晟凯等[61]利用eDNA技术研究邵伯湖浮游动物物种,发现该技术适用于浅水湖泊浮游动物群落的监测,且其结合传统形态学观察的检出效果最佳。冯芸芝等[2]对eDNA宏条形码技术在海洋浮游动物多样性和生态学研究中的应用作了总结,发现该技术能够快速、准确、经济地分析大规模环境样本,并在海洋浮游动物生态学研究中得到了越来越广泛的应用。总之,利用eDNA宏条形码技术可快速而准确地反映浮游动物类群的多样性、分布特征、数量变化等。
表2 基于18S rRNA和COⅠ条形码基因设计的通用引物在利用eDNA宏条形码研究浮游动物多样性中的应用示例
Tab.2
条形码基因 Barcode genes | 长度/bp Length | 引物序列 Primer sequences | 应用示例 Application examples |
---|---|---|---|
COⅠ | 313 | F:WACWGGWTGAACWGTWTAYCCYCC | 筛选出更适合研究浮游动物 DNA 宏条形码引物[53] |
R:TAAACTTCAGGGTGACCAAARAAYCA | |||
COⅠ | 116 | F:TTAGGRGCHCCWGAYATRGCTT | 鉴定枝角类浮游动物物种,并研究其生物量[57] |
R: GCRTGRGCRATHCCHGCWGA | |||
COⅠ | 310 | F:GGWACWGGWTGAACWGTWTAYCCYCC | 研究秦淮河生物多样性[35] |
R:GGRGGRTASACSGTTCASCCSGTSCC | |||
COⅠ | 649 | F:TGTAAAACGACGGCCAGTTCTASWAAT | 鉴定浮游动物休眠卵种类[54] |
R:CAGGAAACAGCTATGACTTCAGGRTGR | |||
COⅠ | 313 | F:GGWACWGGWTGAACWGTWTAYCCYCC | 大规模生物多样性评估[58] |
R:TAIACYTCIGGRTGICCRAARAAYCA | |||
COⅠ | 313 | F:GGWACWGGWTGAACWGTWTAYCCYCC R:TAAACTTCAGGGTGACCAAAAAATCA | 研究加拿大安大略省58个湖泊的浮游动物[59] |
18S rRNA-V4 | 380 | F:CCAGCASCYGCGGTAATTCC | 研究湖泊中微型和超微型真核浮游生物多样性[39] |
R:ACTTTCGTTCTTGATYRA | |||
18S rRNA-V4 | 370 | F:AGGGCAAKYCTGGTGCCAG | 研究鸭绿江口浮游动物多样性[48] |
R:GRCGGTATCTRATCGYCTT | |||
18S rRNA-V9 | 130 | F:GTACACACCGCCCGTC | 分析南海西沙群岛浮游动物多样性[60] |
R:TGATCCTTCTGCAGGTTCACCTAC |
5 浮游生物DNA条形码数据库
目前利用eDNA宏条形码技术研究浮游动植物多样性主要用到的数据库为生命条形码数据库(Barcode of life data systems,BOLD, http://www.boldsystems.org/index.php)和NCBI中的GeneBank数据库(https://www.ncbi.nlm.nih.gov/genbank/),二者均为开放数据库。截止2023年3月31日,BOLD数据库已收集到640 578种物种的条形码序列;录入至BOLD数据库的条形码需经过严格质量筛查和公示,也必须具备物种名称、凭证数据(存储机构和目录信息)、采集记录、标本标识符、序列大于500 bp、引物信息以及原始序列数据文件。GeneBank数据库已更新至2023年2月,其种的数据量比BOLD大,包括241 830 635条序列;录入至GeneBank中的序列也要进行基本的质量检查,但与BOLD相比,不存储序列色谱图、采集元数据或物种照片[62]。BOLD是一种具备存储功能的条形码管理工具,而GeneBank主要完成数据存储,这两个库中的很多数据是重合的,BOLD中的序列会自动传递到GeneBank,BOLD又从GeneBank中周期性挖掘条形码数据[63]。对测序获得的eDNA序列,需要使用比对工具检索比对到相应的数据库,使用BOLD-ID工具将测序获得的eDNA序列比对到BOLD数据库,可查询出与序列最匹配的物种名称、分类单元以及相近物种等;使用NCBI-BLAST工具将测序获得的eDNA序列比对到GeneBank数据库,可查询到与参考序列的相似度并打分,实现物种鉴定。除以上2个主要的数据库外,很多国家都建有本国的DNA条形码数据库,例如中国科学院建立的中国生命条形码信息管理系统和近海海洋DNA条形码资源库[64]、韩国生命条形码数据库[65]、澳大利亚淡水大型无脊椎动物的DNA条形码数据库[66]、中国淡水大型底栖无脊椎动物条形码数据库[67]等。研究者将eDNA测序后得到的序列比对到这些开放或者自有数据库,查询比对率,进而确定物种类型。构建高质量、高准确度的参考数据库是eDNA 宏条形码技术的关键,将测序获得的数据比对到目标序列,如果数据库出现错误或缺失,就会严重影响研究结果的准确性。因此,构建一个具备世界共识的高质量、高准确度数据库是一项规模庞大且艰巨的任务,需要在研究过程中不断更新完善DNA条形码数据库,以提高其精确度和可信程度。
6 小结与展望
传统浮游动植物的形态鉴定容易受鉴定人员的专业水平的影响,而eDNA宏条形码作为一种经济实惠的基因鉴别技术,具备便捷可靠、灵活实用、信息量大等优点,能快捷有序地应用于浮游动植物的鉴定与分类管理。目前eDNA宏条形码技术的应用主要通过研究浮游动植物多样性,以进一步评估水生生态系统物种多样性和健康状况。eDNA宏条形码技术主要包括eDNA样品采集、DNA提取、PCR扩增、高通量测序、序列对比与物种注释等,其准确性从样品采集开始便受影响,要根据不同的水体环境选择合适的采样方法,并在采样的过程中注意样品的代表性、避免样品被污染的情况发生。利用eDNA宏条形码技术研究浮游植物多样性通常使用18S rRNA条形码基因,而研究浮游动物多样性通常使用COⅠ条形码基因,但二者均根据目标基因设计通用引物完成PCR扩增。高质量、高准确度的参考数据库是eDNA 宏条形码技术研究应用的关键,需要在研究过程中不断完善数据库,使其具有更高的准确度且覆盖更为广泛的多基因片段,实现浮游动植物种群结构和数量的精准量化。
参考文献
Next-generation sequencing technologies for environmental DNA research
[J].Since 2005, advances in next-generation sequencing technologies have revolutionized biological science. The analysis of environmental DNA through the use of specific gene markers such as species-specific DNA barcodes has been a key application of next-generation sequencing technologies in ecological and environmental research. Access to parallel, massive amounts of sequencing data, as well as subsequent improvements in read length and throughput of different sequencing platforms, is leading to a better representation of sample diversity at a reasonable cost. New technologies are being developed rapidly and have the potential to dramatically accelerate ecological and environmental research. The fast pace of development and improvements in next-generation sequencing technologies can reflect on broader and more robust applications in environmental DNA research. Here, we review the advantages and limitations of current next-generation sequencing technologies in regard to their application for environmental DNA analysis.© 2012 Blackwell Publishing Ltd.
Methodology of fish eDNA and its applications in ecology and environment
[J].
Predicting the fate of eDNA in the environment and implications for studying biodiversity
[J].
基于Cyt b序列的太湖和洪泽湖翘嘴鲌遗传多样性和遗传结构分析
[J].翘嘴鲌具有很高的营养价值、经济价值和生态价值,近年来其野生资源趋于枯竭,因而掌握翘嘴鲌遗传多样性对于科学保护其种质资源具有重要意义。为了解太湖和洪泽湖翘嘴鲌种质资源遗传状况,通过线粒体Cyt b基因序列测定,分析了其群体的遗传多样性和遗传结构。结果显示,翘嘴鲌Cyt b基因全序列长度为1 141 bp,碱基A+T含量明显高于G+C含量。98条Cyt b序列共检测出29个变异位点,共定义29种单倍型,平均单倍型多样性指数(Hd)和核苷酸多样性指数(Pi)分别为0.923和0.002 74,平均核苷酸差异数(K)为3.127。太湖和洪泽湖群体的Hd分别为0.927和0.816,Pi分别为0.002 85和0.002 20,遗传多样性表现出高Hd、低Pi的特点。分子方差分析结果显示,群体内分子变异占比为15.01%,群体间分子变异占比为84.99%,两群体间遗传分化系数(Fst)为0.150 15(P<0.01),表明两群体间有显著性遗传分化。Tajima’s D中性检验结果为不显著性负值,Fu’s Fs中性检验结果为显著性负值,且歧点分布曲线为单峰型,表明翘嘴鲌在进化过程中经历过群体扩张事件。本研究结果为太湖和洪泽湖翘嘴鲌种质资源管理保护提供了数据资料。
罗氏沼虾3个不同群体线粒体COⅠ基因序列变异及遗传多样性分析
[J].为研究上海选育群体(SC)、浙江养殖群体(ZJ)和泰国野生群体(TL)3个罗氏沼虾群体的遗传多样性,实验对3个不同群体的线粒体COⅠ基因序列进行PCR扩增和测定。在长度为458 bp的COⅠ基因序列中,只检测到8个变异位点和4个单倍型;平均A+T含量(54.4%)高于G+C含量(45.7%)。遗传变异参数分析显示,单倍型多样性指数最高为TL群体(Hd=0.733),核苷酸多样性指数最高为ZJ群体(π=0.005)。AMOVA分析表明,来自群体间的遗传变异(74.5%)高于来自群体内的遗传变异(25.5%)。采用NJ法和UPMGA法构建的系统进化树的趋势一致,都显示SC群体和ZJ群体遗传关系最近,首先聚在一起成为一小支,然后再与TL群体聚为另一支。研究结果可为罗氏沼虾种质资源保护和利用提供参考。
Controls on eDNA movement in streams: transport, retention, and resuspension
[J].Advances in detection of genetic material from species in aquatic ecosystems, including environmental DNA (eDNA), have improved species monitoring and management. eDNA from target species can readily move in streams and rivers and the goal is to measure it, and with that infer where and how abundant species are, adding great value to delimiting species invasions, monitoring and protecting rare species, and estimating biodiversity. To date, we lack an integrated framework that identifies environmental factors that control eDNA movement in realistic, complex, and heterogeneous flowing waters. To this end, using an empirical approach and a simple conceptual model, we propose a framework of how eDNA is transported, retained, and resuspended in stream systems. Such an understanding of eDNA dispersal in streams will be essential for designing optimized sampling protocols and subsequently estimating biomass or organismal abundance. We also discuss guiding principles for more effective use of eDNA methods, highlighting the necessity of understanding these parameters for use in future predictive modeling of eDNA transport.
Biological identifications through DNA barcodes
[J].
The future of environmental DNA in ecology
[J].The contributions of environmental DNA to ecology are reviewed, focusing on diet, trophic interactions, species distributions and biodiversity assessment. Environmental DNA has the potential to dramatically improve quantitative studies in these fields. Achieving this, however, will require large investments of time and money into developing the relevant databases, models, and software.© 2012 Blackwell Publishing Ltd.
环境DNA宏条形码在生物多样性研究与监测中的应用
[J].环境DNA宏条形码(eDNA metabarcoding)技术通过提取水体、土壤、空气中的环境DNA,使用引物PCR扩增与高通量测序,进行物种鉴定与生物多样性评估。作为一种新的监测技术,相比于传统监测技术更加快捷、准确以及对自然环境的破坏小,因此在一定程度上改变了我们调查地球生物多样性的方式。本文综述了环境DNA宏条形码技术的发展历程与操作流程;归纳了在水体、土壤、空气环境中的应用现状,并总结了其独特的间接生物多样性监测方法,同时讨论了优势及存在的问题,以期能为后续生物多样性研究与监测研究提供新的思路和启发。
Utility of eDNA and occupancy models for monitoring an endangered fish across diverse riverine habitats
[J].Environmental DNA (eDNA) studies show great promise for non-invasive surveys of aquatic organisms, but should account for imperfect detection and the influences of biotic and abiotic conditions on detection. We evaluated an eDNA protocol for Roanoke logperch (RLP) Percina rex, an endangered fish of the eastern United States occupying habitats ranging from cold, clear creeks to warm, turbid rivers. We assayed water samples from streams presumed likely to be occupied or unoccupied by RLP based on previous fish surveys. Data were analyzed using multi-scale occupancy models that estimated occurrence and detection probability at the scales of sites, replicate water filters, and replicate PCR reactions, and environmental influences on these probabilities. We detected RLP eDNA at 11 of 12 sites in occupied streams and no sites in presumed-unoccupied streams. In best-supported models, detection was positively related to an index of fish density, whereas other environmental factors had no consistent effects. This approach had a higher detection rate and lower sensitivity to sampling conditions than traditional techniques like snorkeling and electrofishing, suggesting it could provide a powerful tool for assessing the distribution of this and other rare fishes that occur across a wide range of fluvial habitats.
Space-time dynamics in monitoring neotropical fish communities using eDNA metabarcoding
[J].
Assessment of fish communities using environmental DNA: effect of spatial sampling design in lentic systems of different sizes
[J].Freshwater fish biodiversity is quickly decreasing and requires effective monitoring and conservation. Environmental DNA (eDNA)-based methods have been shown to be highly sensitive and cost-efficient for aquatic biodiversity surveys, but few studies have systematically investigated how spatial sampling design affects eDNA-detected fish communities across lentic systems of different sizes. We compared the spatial patterns of fish diversity determined using eDNA in three lakes of small (SL; 3 ha), medium (ML; 122 ha) and large (LL; 4,343 ha) size using a spatially explicit grid sampling method. A total of 100 water samples (including nine, 17 and 18 shoreline samples and six, 14 and 36 interior samples from SL, ML and LL, respectively) were collected, and fish communities were analysed using eDNA metabarcoding of the mitochondrial 12S region. Together, 30, 35 and 41 fish taxa were detected in samples from SL, ML, and LL, respectively. We observed that eDNA from shoreline samples effectively captured the majority of the fish diversity of entire waterbodies, and pooled samples recovered fewer species than individually processed samples. Significant spatial autocorrelations between fish communities within 250 m and 2 km of each other were detected in ML and LL, respectively. Additionally, the relative sequence abundances of many fish species exhibited spatial distribution patterns that correlated with their typical habitat occupation. Overall, our results support the validity of a shoreline sampling strategy for eDNA-based fish community surveys in lentic systems but also suggest that a spatially comprehensive sampling design can reveal finer distribution patterns of individual species.© 2019 John Wiley & Sons Ltd.
Bottom-heavy trophic pyramids impair methylmercury biomagnification in the marine plankton ecosystems
[J].
Fishing for fish environmental DNA: ecological applications, methodological considerations, surveying designs, and ways forward
[J].
Review the detection of aquatic animal species using environmental DNA - a review of eDNA as a survey tool in ecology
[J].
Standards for methods utilizing environmental DNA for detection of fish species
[J].Environmental DNA (eDNA) techniques are gaining attention as cost-effective, non-invasive strategies for acquiring information on fish and other aquatic organisms from water samples. Currently, eDNA approaches are used to detect specific fish species and determine fish community diversity. Various protocols used with eDNA methods for aquatic organism detection have been reported in different eDNA studies, but there are no general recommendations for fish detection. Herein, we reviewed 168 papers to supplement and highlight the key criteria for each step of eDNA technology in fish detection and provide general suggestions for eliminating detection errors. Although there is no unified recommendation for the application of diverse eDNA in detecting fish species, in most cases, 1 or 2 L surface water collection and eDNA capture on 0.7-μm glass fiber filters followed by extraction with a DNeasy Blood and Tissue Kit or PowerWater DNA Isolation Kit are useful for obtaining high-quality eDNA. Subsequently, species-specific quantitative polymerase chain reaction (qPCR) assays based on mitochondrial cytochrome b gene markers or eDNA metabarcoding based on both 12S and 16S rRNA markers via high-throughput sequencing can effectively detect target DNA or estimate species richness. Furthermore, detection errors can be minimized by mitigating contamination, negative control, PCR replication, and using multiple genetic markers. Our aim is to provide a useful strategy for fish eDNA technology that can be applied by researchers, advisors, and managers.
Choice of capture and extraction methods affect detection of freshwater biodiversity from environmental DNA
[J].
Optimizing techniques to capture and extract environmental DNA for detection and quantification of fish
[J].Few studies have examined capture and extraction methods for environmental DNA (eDNA) to identify techniques optimal for detection and quantification. In this study, precipitation, centrifugation and filtration eDNA capture methods and six commercially available DNA extraction kits were evaluated for their ability to detect and quantify common carp (Cyprinus carpio) mitochondrial DNA using quantitative PCR in a series of laboratory experiments. Filtration methods yielded the most carp eDNA, and a glass fibre (GF) filter performed better than a similar pore size polycarbonate (PC) filter. Smaller pore sized filters had higher regression slopes of biomass to eDNA, indicating that they were potentially more sensitive to changes in biomass. Comparison of DNA extraction kits showed that the MP Biomedicals FastDNA SPIN Kit yielded the most carp eDNA and was the most sensitive for detection purposes, despite minor inhibition. The MoBio PowerSoil DNA Isolation Kit had the lowest coefficient of variation in extraction efficiency between lake and well water and had no detectable inhibition, making it most suitable for comparisons across aquatic environments. Of the methods tested, we recommend using a 1.5 μm GF filter, followed by extraction with the MP Biomedicals FastDNA SPIN Kit for detection. For quantification of eDNA, filtration through a 0.2-0.6 μm pore size PC filter, followed by extraction with MoBio PowerSoil DNA Isolation Kit was optimal. These results are broadly applicable for laboratory studies on carps and potentially other cyprinids. The recommendations can also be used to inform choice of methodology for field studies.© 2015 John Wiley & Sons Ltd.
Phytoplankton primary production in the world’s estuarine-coastal ecosystems
[J].. Estuaries are biogeochemical hot spots because they receive large inputs of nutrients and organic carbon from land and oceans to support high rates of metabolism and primary production. We synthesize published rates of annual phytoplankton primary production (APPP) in marine ecosystems influenced by connectivity to land – estuaries, bays, lagoons, fjords and inland seas. Review of the scientific literature produced a compilation of 1148 values of APPP derived from monthly incubation assays to measure carbon assimilation or oxygen production. The median value of median APPP measurements in 131 ecosystems is 185 and the mean is 252 g C m−2 yr−1, but the range is large: from −105 (net pelagic production in the Scheldt Estuary) to 1890 g C m−2 yr−1 (net phytoplankton production in Tamagawa Estuary). APPP varies up to 10-fold within ecosystems and 5-fold from year to year (but we only found eight APPP series longer than a decade so our knowledge of decadal-scale variability is limited). We use studies of individual places to build a conceptual model that integrates the mechanisms generating this large variability: nutrient supply, light limitation by turbidity, grazing by consumers, and physical processes (river inflow, ocean exchange, and inputs of heat, light and wind energy). We consider method as another source of variability because the compilation includes values derived from widely differing protocols. A simulation model shows that different methods reported in the literature can yield up to 3-fold variability depending on incubation protocols and methods for integrating measured rates over time and depth. Although attempts have been made to upscale measures of estuarine-coastal APPP, the empirical record is inadequate for yielding reliable global estimates. The record is deficient in three ways. First, it is highly biased by the large number of measurements made in northern Europe (particularly the Baltic region) and North America. Of the 1148 reported values of APPP, 958 come from sites between 30 and 60° N; we found only 36 for sites south of 20° N. Second, of the 131 ecosystems where APPP has been reported, 37% are based on measurements at only one location during 1 year. The accuracy of these values is unknown but probably low, given the large interannual and spatial variability within ecosystems. Finally, global assessments are confounded by measurements that are not intercomparable because they were made with different methods. Phytoplankton primary production along the continental margins is tightly linked to variability of water quality, biogeochemical processes including ocean–atmosphere CO2 exchange, and production at higher trophic levels including species we harvest as food. The empirical record has deficiencies that preclude reliable global assessment of this key Earth system process. We face two grand challenges to resolve these deficiencies: (1) organize and fund an international effort to use a common method and measure APPP regularly across a network of coastal sites that are globally representative and sustained over time, and (2) integrate data into a unifying model to explain the wide range of variability across ecosystems and to project responses of APPP to regional manifestations of global change as it continues to unfold.\n
Marine microorganisms and global nutrient cycles
[J].
Automatic plankton image classification combining multiple view features via multiple kernel learning
[J].Background: Plankton, including phytoplankton and zooplankton, are the main source of food for organisms in the ocean and form the base of marine food chain. As the fundamental components of marine ecosystems, plankton is very sensitive to environment changes, and the study of plankton abundance and distribution is crucial, in order to understand environment changes and protect marine ecosystems. This study was carried out to develop an extensive applicable plankton classification system with high accuracy for the increasing number of various imaging devices. Literature shows that most plankton image classification systems were limited to only one specific imaging device and a relatively narrow taxonomic scope. The real practical system for automatic plankton classification is even non-existent and this study is partly to fill this gap.Results: Inspired by the analysis of literature and development of technology, we focused on the requirements of practical application and proposed an automatic system for plankton image classification combining multiple view features via multiple kernel learning (MKL). For one thing, in order to describe the biomorphic characteristics of plankton more completely and comprehensively, we combined general features with robust features, especially by adding features like Inner-Distance Shape Context for morphological representation. For another, we divided all the features into different types from multiple views and feed them to multiple classifiers instead of only one by combining different kernel matrices computed from different types of features optimally via multiple kernel learning. Moreover, we also applied feature selection method to choose the optimal feature subsets from redundant features for satisfying different datasets from different imaging devices. We implemented our proposed classification system on three different datasets across more than 20 categories from phytoplankton to zooplankton. The experimental results validated that our system outperforms state-of-the-art plankton image classification systems in terms of accuracy and robustness.Conclusions: This study demonstrated automatic plankton image classification system combining multiple view features using multiple kernel learning. The results indicated that multiple view features combined by NLMKL using three kernel functions (linear, polynomial and Gaussian kernel functions) can describe and use information of features better so that achieve a higher classification accuracy.
Future phytoplankton diversity in a changing climate
[J].
Why do phytoplankton evolve large size in response to grazing
?[J].
Long-term dynamics of adaptive evolution in a globally important phytoplankton species to ocean acidification
[J].
2012年夏季长湖浮游植物群落特征及其与环境因子的关系
[J].为查明长湖浮游植物群落特征及其水环境影响因子, 并确定水体富营养化程度, 于2012年夏季对长湖浮游植物及相关环境因子进行调查检测分析, 运用藻类生物学法和综合营养状态指数法, 对长湖水体营养状态进行综合评定, 同时利用典范对应分析法(CCA)对浮游植物与环境因子的关系进行了分析。结果表明, 2012年夏季长湖浮游植物共有53种(含变种、变型), 隶属于7门41属, 其中以绿藻最多(24种, 占总数量的38.9%), 其次为蓝藻(15种, 占总数量的36.0%)和硅藻(7种, 占总数量的14.1%)。优势种(优势度指数大于0.02)共10种, 其中两栖颤藻(Oscillatoria amphibia)是4个区域的共有优势种, 最高优势度达0.72。浮游植物丰度为12.03 × 10 <sup>6</sup>- 62.13 × 10 <sup>6</sup>cell·L <sup>-1</sup>, 平均值为27.71 × 10 <sup>6</sup>cell·L <sup>-1</sup>。浮游植物丰度的平面分布呈现圆心湖、海子湖、马洪台、庙湖依次降低的特点。浮游植物多样性指数变化范围为0.89-3.24, 均匀度指数变化范围为0.23-0.83。选取叶绿素a、总磷、总氮、透明度和化学需氧量5项参数计算得出综合营养化指数。通过藻类生物学法和综合营养状态指数法进行综合评价发现: 2012年夏季长湖处于中度富营养化到富营养化程度。典范对应分析表明: 浮游植物空间分布主要受总氮、总悬浮物、总磷、溶氧以及亚硝酸氮等环境因子的影响。针状蓝纤维藻(Dactylococcopsis acicularis)、两栖颤藻、席藻属(Phormidium)、鱼腥藻属(Anabeana)等蓝藻对总氮的需求较大。长湖各站点由于在不同程度上受到地形、人为干扰以及水动力条件的影响, 它们与环境因子的典范对应分析表现出明显的区域性。
Analysis of spatio-temporal variation in phytoplankton and its relationship with water quality parameters in the South-to-North Water Diversion Project of China
[J].
Metabolic functional community diversity of associated bacteria during the degradation of phytoplankton from a drinking water reservoir
[J].In the drinking water reservoir ecosystem, phytoplankton and bacteria play important roles in shaping freshwater health and function. In this work, the associated bacterial community functional diversity during degradation of phytoplankton was determined using the substrate utilization profiling (BIOLOG) technique, meanwhile, the composition and concentration of phytoplankton were examined using a microscope. The results indicated that Euglena decreased 58.33% from 0 to 38 d, while the smallest degradation of Bacillariophyta was 20.19%. Average well color development (AWCD590nm) increased during the static periods from 0 to 38 d; however, the AWCD590nm of 18 and 38 d had no significant difference (p < 0.05). The Simpson’s index (D) was in accordance with Shannon’s diversity (H) and species richness(S); it was measured to be18 > 38 > 5 > 0 d. There were significant differences in the pattern and level of carbon sources used by the phytoplankton-associated bacteria. In addition, the principle component analyses (PCA) suggested that the first principle component (PC1) and the second principle component (PC2) explained 46.76% and 21.49% of the total variation for bacterial community, respectively. Redundancy analysis (RDA) revealed that cell abundance of phytoplankton was negatively correlated with the AWCD590nm, amino acids and other functional indexes. Therefore, the data suggest that there are differences in the phytoplankton-associated bacterial community functional diversity during different static stages of water samples collected from the drinking water reservoir.
基于多个扩增子的DNA metabarcoding技术探究黄海微型真核浮游植物多样性
[J].
Comparison of water sampling between environmental DNA metabarcoding and conventional microscopic identification: a case study in Gwangyang Bay, South Korea
[J].
Metabarcoding of zooplankton diversity within the Chukchi Borderland, Arctic Ocean: improved resolution from multi-gene markers and region-specific DNA databases
[J].
Insights into global diatom distribution and diversity in the world's ocean
[J].
基于环境DNA宏条形码的鄱阳湖真核浮游植物多样性研究
[J/OL].
Predation by an omnivorous fish and food availability alter zooplankton functional diversity: a microcosm approach
[J].
Rapid measurement of total lipids in zooplankton using the sulfo-phospho-vanillin reaction
[J].Zooplankton provide a vital source of nutrition to a variety of fish and marine predators. Measuring the total lipid content of zooplankton provides important information about diet quality available to predators, revealing details about trophic dynamics and ecosystem status. We analyze the performance of a microplate assay, utilizing the sulfo-phospho-vanillin (SPV) reaction, to quantify the total lipid content of various large crustacean zooplankton in a rapid and high throughput manner. Pilot experiments were performed by measuring the total lipid content of purchased freeze-dried zooplankton ( and ) by both SPV and gravimetric analysis (low throughput and requires large sample size). The results of the SPV assay were not statistically different from gravimetric analysis for either species (> 0.05). Further, an inter-laboratory comparison study was performed to measure the total lipid content (% of wet mass) of field-collected Arctic and North Pacific zooplankton (copepods ( = 19) and euphausiids ( = 29)) of various species utilizing multiple analysis methods. Results from thin layer chromatography with flame ionization detection (TLC-FID) demonstrated that lipid classes in zooplankton samples varied in composition of steryl/wax esters (3-95%), triacylglycerols (1-52%), free-fatty acids (0.4-25%), sterols (0-4%) and polar lipids (1-42%). Despite this variation in lipid class composition among samples, the results of the SPV assay agreed well with gravimetric analysis. The mean absolute and relative differences between SPV and gravimetric analysis for all zooplankton lipids in this study were 1.0% and 11.6%, respectively. The SPV assay is rapid (<2 hours), high throughput (25 samples processed in parallel), low cost (supplies <$ 0.67 per sample), precise (inter assay CV = 6.9%, intra assay CV = 6.0%), sensitive (limit of detection < 1.7 micrograms of lipid per analysis), and accurate when calibrated with appropriate standards.
Zooplankton and the ocean carbon cycle
[J].Marine zooplankton comprise a phylogenetically and functionally diverse assemblage of protistan and metazoan consumers that occupy multiple trophic levels in pelagic food webs. Within this complex network, carbon flows via alternative zooplankton pathways drive temporal and spatial variability in production-grazing coupling, nutrient cycling, export, and transfer efficiency to higher trophic levels. We explore current knowledge of the processing of zooplankton food ingestion by absorption, egestion, respiration, excretion, and growth (production) processes. On a global scale, carbon fluxes are reasonably constrained by the grazing impact of microzooplankton and the respiratory requirements of mesozooplankton but are sensitive to uncertainties in trophic structure. The relative importance, combined magnitude, and efficiency of export mechanisms (mucous feeding webs, fecal pellets, molts, carcasses, and vertical migrations) likewise reflect regional variability in community structure. Climate change is expected to broadly alter carbon cycling by zooplankton and to have direct impacts on key species.
Changing climate cues differentially alter zooplankton dormancy dynamics across latitudes
[J].In seasonal climates, dormancy is a common strategy that structures biodiversity and is necessary for the persistence of many species. Climate change will likely alter dormancy dynamics in zooplankton, the basis of aquatic food webs, by altering two important hatching cues: mean temperatures during the ice-free season, and mean day length when lakes become ice free. Theory suggests that these changes could alter diversity, hatchling abundances and phenology within lakes, and that these responses may diverge across latitudes due to differences in optimal hatching cues and strategies. To examine the role of temperature and day length on hatching dynamics, we collected sediment from 25 lakes across a 1800 km latitudinal gradient and exposed sediment samples to a factorial combination of two photoperiods (12 and 16 h) and two temperatures (8 and 12 °C) representative of historical southern (short photoperiod, warm) and northern (long photoperiod, cool) lake conditions. We tested whether sensitivity to these hatching cues varies by latitudinal origin and differs among taxa. Higher temperatures advanced phenology for all taxa, and these advances were greatest for cladocerans followed by copepods and rotifers. Although phenology differed among taxa, the effect of temperature did not vary with latitude. The latitudinal origin of the egg bank influenced egg abundance and hatchling abundance and diversity, with these latter effects varying with taxa, temperature and photoperiod. Copepod hatchling abundances peaked at mid-latitudes in the high temperature and long photoperiod treatments, whereas hatchling abundances of other zooplankton were greatest at low latitudes and high temperature. The overall diversity of crustacean zooplankton (copepods and cladocerans) also reflected distinct responses of each taxa to our treatments, with the greatest diversity occurring at mid-latitudes (~56 °N) in the shorter photoperiod treatment. Our results demonstrate that hatching cues differ for broad taxonomic groups that vary in developmental and life-history strategies. These differences are predicted to drive latitude-specific shifts in zooplankton emergence with climate change and could alter the base of aquatic food webs.© 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.
Effects of increased temperature, drought, and an insecticide on freshwater zooplankton communities
[J].In the present study we performed a microcosm experiment to assess the effects of the insecticide lufenuron on zooplankton communities exposed to increased temperature and drought in (semi-)arid regions. The experiment consisted of 3 environmental scenarios, assessed in 2 parts. Firstly, we assessed how water temperature (20 and 28 °C) affects the sensitivity and resilience of the zooplankton community to lufenuron. Secondly, we investigated the influence of drought on the structure of the zooplankton community at a high water temperature (28 °C) and evaluated its possible interaction with lufenuron. The results show that the community exposed to lufenuron at 28 °C had a faster lufenuron-related response and recovery than the community at 20 °C. The combined effects of lufenuron and temperature resulted in a synergistic effect on some taxa (Daphnia sp., Cyclopoida, and Copepoda nauplii). The tested zooplankton community had a high resilience to drought, although some particular taxa were severely affected after desiccation (Calanoida). Interactions between drought and lufenuron were not statistically significant. However, rewetting after desiccation contributed to lufenuron remobilization from sediments and resulted in a slight Cyclopoida population decline at high exposure concentrations. The study shows how environmental conditions related to global change in (semi-)arid regions may influence chemical fate and the vulnerability of zooplankton communities to chemical stress. Environ Toxicol Chem 2019;38:396-411. © 2018 SETAC.© 2018 SETAC.
Biodiversity and ecosystem function in the gulf of maine: pattern and role of zooplankton and pelagic nekton
[J].
Functional shifts in estuarine zooplankton in response to climate variability
[J].
Widespread agrochemicals differentially affect zooplankton biomass and community structure
[J].
DNA metabarcoding of littoral hard-bottom communities: high diversity and database gaps revealed by two molecular markers
[J].Biodiversity assessment of marine hard-bottom communities is hindered by the high diversity and size-ranges of the organisms present. We developed a DNA metabarcoding protocol for biodiversity characterization of structurally complex natural marine hard-bottom communities. We used two molecular markers: the “Leray fragment” of mitochondrialcytochrome c oxidase(COI), for which a novel primer set was developed, and the V7 region of the nuclear small subunit ribosomal RNA (18S). Eight different shallow marine littoral communities from two National Parks in Spain (one in the Atlantic Ocean and another in the Mediterranean Sea) were studied. Samples were sieved into three size fractions from where DNA was extracted separately. Bayesian clustering was used for delimiting molecular operational taxonomic units (MOTUs) and custom reference databases were constructed for taxonomic assignment. Despite applying stringent filters, we found high values for MOTU richness (2,510 and 9,679 MOTUs with 18S and COI, respectively), suggesting that these communities host a large amount of yet undescribed eukaryotic biodiversity. Significant gaps are still found in sequence reference databases, which currently prevent the complete taxonomic assignment of the detected sequences. In our dataset, 85% of 18S MOTUs and 64% of COI MOTUs could be identified to phylum or lower taxonomic level. Nevertheless, those unassigned were mostly rare MOTUs with low numbers of reads, and assigned MOTUs comprised over 90% of the total sequence reads. The identification rate might be significantly improved in the future, as reference databases are further completed. Our results show that marine metabarcoding, currently applied mostly to plankton or sediments, can be adapted to structurally complex hard bottom samples. Thus, eukaryotic metabarcoding emerges as a robust, fast, objective and affordable method to comprehensively characterize the diversity of marine benthic communities dominated by macroscopic seaweeds and colonial or modular sessile metazoans. The 18S marker lacks species-level resolution and thus cannot be recommended to assess the detailed taxonomic composition of these communities. Our new universal primers for COI can potentially be used for biodiversity assessment with high taxonomic resolution in a wide array of marine, terrestrial or freshwater eukaryotic communities.
A new versatile primer set targeting a short fragment of the mitochondrial COⅠregion for metabarcoding metazoan diversity: application for characterizing coral reef fish gut contents
[J].
RNA metabarcoding helps reveal zooplankton community response to environmental stressors
[J].
GenBank
[J].
Over 2.5 million COⅠsequences in GenBank and growing
[J].
Korea barcode of life database system (KBOL)
[J].
A DNA barcode database of Australia’s freshwater macroinvertebrate fauna
[J].Macroinvertebrates are widely used for monitoring freshwater ecosystems. In most monitoring programs, identifications take substantial time and expense. Methods that improve the speed, accuracy and cost-effectiveness of macroinvertebrate identification would benefit such programs. Increasingly, DNA barcodes are being used to provide accurate species-level identifications and have the potential to change how macroinvertebrates are routinely identified. Herein we discuss the need for DNA barcodes of freshwater macroinvertebrates with particular reference to Australia. We examine the use of DNA barcodes for species identification and compare DNA barcoding efforts of macroinvertebrates from Australia with those globally. We consider the role of high-throughput sequencing of DNA barcodes in freshwater bioassessment and its potential use in biosurveillance. Finally, we outline a strategy for developing a comprehensive national DNA barcode database for Australian freshwater macroinvertebrates and present the initial efforts in creating this database.
中国淡水大型底栖无脊椎动物条形码数据库构建
[J].
/
〈 |
|
〉 |
