Environmental DNA最新文献

{"title":"eDNA State and Medium Affect DNA Degradation Patterns in Seminatural Systems of Southern African Waterholes","authors":"Irmgard Sedlmayr,&nbsp;Tamara Schenekar","doi":"10.1002/edn3.70025","DOIUrl":"https://doi.org/10.1002/edn3.70025","url":null,"abstract":"<p>Environmental DNA (eDNA) has evolved into a valuable asset of the ecologists' toolkit, enabling time- and cost-efficient biodiversity assessments in a wide variety of ecosystems. Since eDNA can be isolated from a broad range of environmental substrates, its persistence times in those media are of decisive importance for drawing inferences about species presence. For the first time, we characterize eDNA persistence in water and sediment samples of seminatural waterholes in a savanna system in South Africa to gain a better understanding of eDNA decay in these waterbodies. Using mesocosm experiments, we tracked eDNA decay in two different DNA states (extracellular and membrane bound), during two different seasons (wet and dry), and from two different substrates (surface water and sediment). Extracellular DNA degraded rapidly in a first-order exponential decay fashion and membrane-bound DNA exhibited a slower decline with more intricate patterns, involving initial reduction followed by a subsequent increase in measured DNA concentrations. The latter we attribute to cell disassociation and cell lysis at 24–48 h after introduction into the environment. Higher stochasticity of membrane-bound DNA capture in the dry season highlights the need for higher sampling efforts in natural systems in which eDNA is presumably more patchily distributed. Additionally, we observed longer eDNA persistence in sediments than in water samples, presumably due to better protection from nucleases. We could not reveal any effects of environmental parameters on eDNA decay, emphasizing that further research is needed to better understand eDNA dynamics in those waterbodies in order to exploit their full potential for eDNA-based bioassessments in those systems.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142525148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interlaboratory Evaluation of Bretziella fagacearum Molecular Detection Assays to Guide the eDNA Monitoring of Oak Wilt Disease","authors":"Marie-Krystel Gauthier,&nbsp;Abdelmadjid Djoumad,&nbsp;Tara L. Bal,&nbsp;Guillaume J. Bilodeau,&nbsp;Marc F. DiGirolomo,&nbsp;Meher Ony,&nbsp;Denita Hadziabdic,&nbsp;Kelsey C. McLaughlin,&nbsp;Laura Miles,&nbsp;Isabel Munck,&nbsp;Karen Lynn Snover-Clift,&nbsp;Philippe Tanguay","doi":"10.1002/edn3.70012","DOIUrl":"https://doi.org/10.1002/edn3.70012","url":null,"abstract":"<p>Oak wilt disease, caused by the fungus <i>Bretziella fagacearum</i>, can kill mature red oaks within months of infection, severely affecting biodiversity, landscapes, and industries. The disease, originally only present in the United States, was officially reported for the first time in Canada in June 2023. The aim of this study was to suggest a standardized assay and sample processing method to optimize oak wilt detection both in infection centers and ahead of the disease front. Two previously published molecular assays, a Nested PCR and a TaqMan qPCR, were compared to detect <i>B. fagacearum</i> in a variety of samples in a ring trial across five laboratories. Sample types investigated included eDNA from trapped insect vectors (sorted insects and bulk content from traps), infested and healthy oak wood chips, and <i>B. fagacearum</i> conidia dilutions. Results demonstrated that both Nested and TaqMan assays can be used for molecular confirmation of oak wilt, and results are reproducible across different labs. There is a general agreement between both detection assays when testing true-positive and true-negative samples. Both methods demonstrated overall good accuracy. The TaqMan assay was more sensitive and detected lower amounts of DNA target. Both tests were 100% specific to oak wood samples, which was the best sample type to use for detection. In general, samples with high Cts were more prompted to yield false negative Nested results. Detecting oak wilt from bulk insect samples was by far more rapid than sorted sap beetles, but resulted in lower detection signals, especially with the Nested assay. The time-period when the insect traps were set up also had considerable influence on detection results. We hope this study helps to formulate guidelines in oak wilt detection and biosurveillance management.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70012","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142449191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continual Day–Night eDNA Detectability Amidst Diel Reef Species Fluctuations on Diver Transects","authors":"Katrina M. West,&nbsp;Tyson R. Jones,&nbsp;Lara Denis-Roy,&nbsp;Olivia J. Johnson,&nbsp;Ella Clausius,&nbsp;Graham Edgar,&nbsp;Bruce Deagle","doi":"10.1002/edn3.70018","DOIUrl":"https://doi.org/10.1002/edn3.70018","url":null,"abstract":"<p>Recent research into the spatiotemporal dynamics of eDNA in marine environments indicates that eDNA signals are highly localized and may dissipate beyond detection levels within a few hours of production. This affects whether single-timepoint eDNA sampling, which generally occurs during daylight hours, or cyclic (day/night) interval eDNA sampling is necessary to detect both diurnal and nocturnal marine species. Our study investigated short-term variability in eDNA derived from fishes and macroinvertebrates across three temperate reef sites in eastern Tasmania, Australia. Simultaneous eDNA and underwater visual census (UVC) diver transect surveys were conducted every 6 h over a 24-h period to investigate whether eDNA was able to detect marine species outside of their UVC-observed diel activity. We report that single-timepoint eDNA sampling can detect both diurnal and nocturnal species on temperate reefscapes. A lack of eDNA compositional turnover between day and night suggests that eDNA persists beyond 12 h and/or is continuously produced by both diurnal and nocturnal reef taxa, irrespective of diel behavioral changes observed by UVC. Given high eDNA sample variability, however, we recommend a high replication level (&gt; 10 × 1 L samples) to produce robust site community composition profiles. This study builds on emerging literature on short-term variability in eDNA, assisting in the design of future eDNA studies at sites with pronounced variation in faunal activity between day and night.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142451156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effect of Spatio-Temporal Sampling and Biological Replication on the Detection of Kelp Forest Fish Communities Using eDNA Metabarcoding","authors":"Kira-Lee Courtaillac,&nbsp;Jannes Landschoff,&nbsp;Kelvin Hull,&nbsp;Sophie von der Heyden","doi":"10.1002/edn3.70023","DOIUrl":"https://doi.org/10.1002/edn3.70023","url":null,"abstract":"<p>Environmental DNA (eDNA) metabarcoding surveys can support the acquisition of extensive biodiversity data to support ecosystem monitoring and conservation actions. However, the optimization of eDNA metabarcoding project design is essential to capture spatio-temporal heterogeneity of eDNA signals and maximize diversity detection. In this study, we developed a system-specific approach to detect fish communities in kelp forests, by analyzing fine-scale spatio-temporal patterns in eDNA signals at two sites along the South African coastline, as well as testing the effect of biological replication and pooling of replicates on species detection. At each site, samples were collected at two stations along the shoreline at two depth zones, and this was repeated at two time points (24 h apart). We detected 113 operational taxonomic units (OTUs) across 32 families, but fewer than 20% of OTUs could be assigned to species, indicating that barcode reference libraries need to be drastically improved. We detected significant differences in communities across small spatial scales (&lt; 600 m) and time points, suggesting that to best capture a site's diversity patterns, samples should be collected at multiple points and times within at least 24 h. To detect ~80% of the fish community, including some low abundance species, a minimum of four samples appear sufficient. In addition, a higher number of OTUs (76 vs. 65) were found in individual replicates than in any of the pools. However, pooling samples prior to sequencing can still detect valuable broad-scale biodiversity patterns for monitoring and can offset the decrease in data resolution with the benefit of accumulating comprehensive data from increased sampling efforts over time. As a pilot investigation into how best to maximize kelp forest-associated fish communities, this study provides a basis for optimizing sampling design for coastal eDNA-based surveys in southern Africa and strengthens the development of long-term eDNA monitoring programs to better support conservation and management actions.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142435424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Insights Into the Population Structure of Hector's Dolphin (Cephalorhynchus hectori) Revealed Using Environmental DNA","authors":"S. M. Bennington,&nbsp;S. D. Bourke,&nbsp;S. P. Wilkinson,&nbsp;N. Englebert,&nbsp;D. M. Bond,&nbsp;G.-J. Jeunen,&nbsp;S. Dawson,&nbsp;E. Slooten,&nbsp;P. W. Dillingham,&nbsp;W. J. Rayment,&nbsp;A. Alexander","doi":"10.1002/edn3.70024","DOIUrl":"https://doi.org/10.1002/edn3.70024","url":null,"abstract":"<p>Environmental DNA (eDNA) is frequently used for detecting species and describing biodiversity through metabarcoding techniques. More recently, there has been emerging evidence that eDNA can be used to investigate intraspecific variability, providing novel pathways to explore population genetics questions. However, it can be difficult to distinguish between true intraspecific variation and PCR/sequence error, and the presence of DNA from multiple individuals makes using traditional frequency-based approaches challenging. Here, we explore how eDNA can be used to investigate population structure of Hector's dolphin (<i>Cephalorhynchus hectori),</i> an endemic, endangered, and culturally important (taonga) species. In doing so, we present a simple and effective method to filter out noise due to PCR/sequence error and show how treating haplotype detections equally can provide similar results to frequency-based approaches from traditional sampling methods. Over the 2022/23 Austral summer, we collected 85 water samples close to Hector's dolphins, and three negative controls, across three areas on the east coast of Aotearoa New Zealand's South Island: Banks Peninsula (<i>n</i> = 41), Timaru (<i>n</i> = 33), and Dunedin (<i>n</i> = 14). We targeted a 348 bp region of the cetacean D-loop in the mitochondrial DNA (<i>mt</i>DNA) and obtained positive detections in 68 (77%) water samples, confidently identifying seven haplotypes across the study area. The occurrence of specific haplotypes and the overall frequencies in Banks Peninsula and Timaru matched well with previous tissue-based studies and were similar to other East Coast South Island (ECSI) subpopulations. In Dunedin, however, our results indicate a closer relationship to South Coast populations, suggesting that the membership within the ECSI population be reconsidered, which has implications for how this subpopulation is managed. We show that eDNA sampling can be used to elucidate matrilineal population structure for Hector's dolphin and provide a simple method that could be applied to other eDNA-based studies of any taxa.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142435422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Validation of an eDNA-based workflow for monitoring inter- and intra-specific CytB haplotype diversity of alpine amphibians","authors":"Lucia Zanovello,&nbsp;Filipa M. S. Martins,&nbsp;Matteo Girardi,&nbsp;Stefano Casari,&nbsp;Giulio Galla,&nbsp;Pedro Beja,&nbsp;Paolo Pedrini,&nbsp;Giorgio Bertorelle,&nbsp;Heidi C. Hauffe","doi":"10.1002/edn3.573","DOIUrl":"https://doi.org/10.1002/edn3.573","url":null,"abstract":"<p>Environmental DNA (eDNA) analysis is a promising tool for monitoring wild animal populations and, more recently, their genetic variability. In this study, we used the mitochondrial Cytochrome B gene to develop and apply new eDNA metabarcoding assays targeting amphibian families and genera in order to estimate both inter- and intraspecific genetic diversity. We designed and tested seven new primer pairs (a) in silico against an amphibian reference database based on the target genera; (b) in vitro on tissue samples of the target species; and (c) in situ on water samples from 38 wetlands in the Province of Trento (Italy). Overall, most target species were amplified successfully, although some markers also amplified non-target amphibian species. In addition, to complete the workflow, we compared the performance of three different bioinformatic pipelines (namely, MICCA with VSEARCH, and OBITools using ecotag or metabinkit), in retrieving reads and exact sequence variants from the metabarcoding datasets. Overall, the MICCA based pipeline retrieved more reads, but less putative haplotypes of amphibians. After comparing these sequences with previously known haplotypes from tissue-based studies, when the aim is to both decrease the probability of detecting false haplotypes and retrieve the highest number of reads, we suggest using MICCA+VSEARCH, unless a direct comparison with tissue-based genetic data is possible.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.573","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142435506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"V9 Hypervariable Region Metabarcoding Primers for Euglenozoa and Metamonada","authors":"Jiří Novák,&nbsp;Sebastian Cristian Treitli,&nbsp;Zoltán Füssy,&nbsp;Kristína Záhonová,&nbsp;Blanka Hamplová,&nbsp;Štěpánka Hrdá,&nbsp;Vladimír Hampl","doi":"10.1002/edn3.70022","DOIUrl":"https://doi.org/10.1002/edn3.70022","url":null,"abstract":"<p>Short amplicon sequencing is a commonly used method to study the diversity of organisms in various habitats. The hypervariable regions of the small subunit rRNA gene (18S rDNA) are the most general barcodes for eukaryotes, which can provide detailed taxonomic information across a wide range of eukaryotic diversity. However, some organisms are often missed by universal primers, which have difficulty amplifying their barcodes. In this study, specific primers were designed for the amplification of the highly diverse 18S-V9 region of the Euglenozoa and Metamonada groups. The performance of the newly designed primers—V9Eug and V9Meta—was compared with the universal V9 primer on cultured communities derived from a range of freshwater environments of the Soos Natural Reserve and the Slavkov Forest in the Czech Republic. The V9Eug primer was more specific with Euglenozoa representing 91.8% of reads and 57.0% of OTUs, while the V9Meta primer showed lower specificity with only 48.4% of reads and 19.7% of OTUs assigned to Metamonada. Both the Euglenozoa and Metamonada primer pairs significantly improved recovery of their target groups compared to the universal V9 primer pair, detecting 2.7 and 1.8 times more OTUs, respectively. These results provide a more sensitive protocol for studying the diversity of these eukaryotic taxa.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142429921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying Key Environmental Drivers of Reach-Scale Salmonid eDNA Recovery With Random Forest","authors":"Shawn A. Melendy,&nbsp;John R. Olson","doi":"10.1002/edn3.70001","DOIUrl":"https://doi.org/10.1002/edn3.70001","url":null,"abstract":"<p>Environmental DNA (eDNA) sampling from rivers has emerged as a promising new method for monitoring freshwater organisms of management concern. However, eDNA sampling cannot yet offer reliable estimates of a target species' abundance/biomass or confident determinations of a species' absence from a river segment. To unlock these abilities—and thereby greatly improve eDNA as a tool for management decision-making—the influence of local environmental factors on eDNA fate must be better understood. At nine river sites across the central California coast, we added a known quantity of novel eDNA (Brook Trout, <i>Salvelinus fontinalis</i>) and collected eDNA at sequential downstream distances for qPCR analysis. We then used random forest modeling to identify the most important environmental factors to reach-scale (≤ 200 m) sampling outcomes and characterize salmonid eDNA fate. Our final model identified six factors important to sampling outcomes, including five environmental factors (discharge, local catchment calcium oxide content, average depth of the sampling cross-section, presence of pools, and impervious cover of the watershed) and one factor regarding our experimental design (the number of qPCR technical replicates). Our results highlight the notable effects of cross-sectional area, turbulence, and catchment geology on eDNA fate, and we suggest the discharge and presence of pools as useful proxies for evaluating a site's favorability for eDNA recovery.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142429915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-Environment Quantification of Parasite and Intermediate Host DNA on Pasture for Fine-Scale Disease Risk Assessment","authors":"Christopher McFarland,&nbsp;Emer McCann,&nbsp;Peter McCann,&nbsp;Eric R. Morgan,&nbsp;Nikki J. Marks,&nbsp;Paul McVeigh,&nbsp;Geoffrey N. Gobert","doi":"10.1002/edn3.70027","DOIUrl":"https://doi.org/10.1002/edn3.70027","url":null,"abstract":"<p>Parasite transmission occurs in complex environments comprising multiple matrices. Trematode parasites of ruminant livestock such as the liver fluke, <i>Fasciola hepatica</i> and the rumen fluke, <i>Calicophoron daubneyi</i>, show affinity with freshwater environments shared with their amphibious snail intermediate host, <i>Galba truncatula</i>. Isolation of environmental DNA (eDNA) from these parasites and their snail hosts in water draining from grazing land provides opportunities for improved molecular diagnostic detection and can help identify infection risks at farm level. The detection and quantification of eDNA from other environmental matrices has received less attention but would improve the understanding of parasite dynamics on pasture. Our study has considerably extended eDNA sampling methods for the detection of parasitic trematodes of ruminant livestock and their snail intermediate host by including for the first time the analysis of soil and herbage environmental samples alongside water collections. A droplet digital PCR (ddPCR) workflow was developed to detect parasite and snail eDNA from soil, herbage, and water collected from livestock farms. For the first time, <i>C</i>. <i>daubneyi</i> eDNA was isolated from agricultural soil alongside water samples and <i>G</i>. <i>truncatula</i> eDNA was detected in water, soil, and herbage samples. No environmental samples were positive for <i>F</i>. <i>hepatica</i> eDNA. Assessing multiple environmental matrices increased the number of positive sites. Future implementation of eDNA detection methods alongside traditional parasite diagnostics can underpin more holistic evaluations of the environmental components of parasite epidemiology and facilitate adaptation to changing disease patterns.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142429920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Sinking Dead—Arctic Deep-Sea Scavengers' Diet Suggests Nekton as Vector in Benthopelagic Coupling","authors":"Lara Schmittmann,&nbsp;Sophie V. Schindler,&nbsp;Till Bayer,&nbsp;Janina Fuss,&nbsp;Charlotte Havermans,&nbsp;Véronique Merten,&nbsp;Henk-Jan T. Hoving","doi":"10.1002/edn3.70020","DOIUrl":"https://doi.org/10.1002/edn3.70020","url":null,"abstract":"<p>Many benthic deep-sea animals rely on carcasses from the overlying water column that sink to the seafloor and form local organic enrichments known as food falls. This flux of organic carbon from the shallow pelagic to the deep sea is part of the biological carbon pump (BCP) and as such contributes to carbon sequestration. For a complete understanding of local carbon budgets, it is crucial to identify the diversity and distribution of sinking carcasses which are difficult to detect by observational methods. Here, we analyzed the diet of the abundant amphipod scavenger, <i>Eurythenes gryllus</i>, by DNA metabarcoding to assess their potential to identify food falls in the Fram Strait, a gateway to the Arctic. <i>E. gryllus</i> scavenges on nekton but so far it was not certain whether this represents their main diet. We detected dietary taxa (26 in total) in 20 out of 101 analyzed amphipods. We found that amphipods primarily fed on larger nekton including fish, cephalopods, and mammals, with bony fish being the most targeted food source in terms of diversity and abundance. Only one amphipod had fed on a gelatinous organism. These results support the hypothesis that <i>E. gryllus</i> targets mostly nekton food falls. The diversity of dietary taxa differed between the Eastern and Western Fram Strait, which suggests regional variability in food falls availability. We also detected, for the first time in <i>E. gryllus</i>, infections with the parasitic dinoflagellate <i>Hematodinium</i>. This detection demonstrates the potential of metabarcoding for revealing both food web dynamics and host–parasite interactions in the deep sea. <i>E. gryllus</i> seems a promising “natural sampler” to monitor the diversity of deep-sea food falls which will help to investigate the importance of medium-sized food falls in local vertical carbon export in a rapidly changing Arctic Ocean.</p>","PeriodicalId":52828,"journal":{"name":"Environmental DNA","volume":"6 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/edn3.70020","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142404627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}