Invasive-species biomonitoring via eDNA

Environmental DNA (eDNA) biomonitoring detects species from the genetic material they shed into water, soil or air, without capturing a single organism. It is the fastest-growing segment of ecological consulting because invasive species cause outsized damage: zebra and quagga mussels clog the cooling pipes of hydropower and nuclear plants, Sosnowsky’s hogweed degrades terrestrial ecosystems, and invasive algae trigger fish kills. Traditional capture monitoring (nets, electrofishing, visual surveys) is slow, labour- intensive and destructive; filtering one or two litres of river water can reveal any species in hours, enabling early intervention when eradication is still cheap. The technology stack pairs targeted droplet-digital PCR (ddPCR), which detects single molecules of invasive-species DNA at concentrations below one copy per millilitre, with NGS metabarcoding that inventories whole communities from universal markers (12S for fish, COI for invertebrates, 16S for bacteria, ITS for fungi). The EU Water Framework Directive now treats eDNA as a core ecological indicator, US NEPA reviews require protected-species clearance on construction sites, and the IMO Ballast Water Convention drives port surveillance. The six organizations span sequencers (Illumina, Oxford Nanopore), detection instruments (Bio-Rad), service labs (NatureMetrics, BGI) and reference research (Institute of Hydrobiology CAS).

Key directions of eDNA invasive-species biomonitoring:

1. Droplet-digital PCR target detection: splitting a sample into 20,000 nanolitre droplets detects single DNA molecules of a target invader (zebra mussel, Asian carp) below one copy per millilitre.
2. NGS metabarcoding: universal markers (12S, COI, 16S, ITS) sequenced on Illumina platforms inventory total biodiversity from one filtered sample.
3. Portable long-read sequencing: Oxford Nanopore MinION reads eDNA in the field, off-grid, for real-time species calls.
4. Automated extraction and field sampling: robotic magnetic-bead stations and peristaltic field pumps standardize hundreds of samples a day.

Sectoral value chain#

[water / soil / air sample] ──> [membrane filtration] ──> [eDNA extraction]
                                                                  │
                                                  (ddPCR target / NGS metabarcoding)
                                                                  │
                                                                  ▼
[B2B ecological report] <─── [bioinformatics] <─── [sequencing]

Value chain levels#

Cross-cutting technologies of the sector:

• edna-metabarcoding: PCR amplification of universal barcode markers (12S, COI, 16S, ITS) followed by NGS sequencing for total-community biodiversity inventory.
• droplet-digital-pcr: partitioning a sample into 20,000 nanolitre droplets for absolute, single-molecule quantification of target invasive-species DNA.
• portable-nanopore-sequencing: real-time, off-grid long-read sequencing on Oxford Nanopore MinION devices for in-field species identification.

The stack combines field sampling, single-molecule detection and reference- database bioinformatics.

1. Droplet-digital PCR target detection:
   • the Bio-Rad QX200 partitions an eDNA reaction into 20,000 nanolitre droplets that undergo PCR with TaqMan fluorescent probes; a droplet reader counts positive droplets for absolute quantification, detecting a target invader below one copy per millilitre where qPCR would return a false negative.
2. NGS metabarcoding:
   • universal barcode regions are PCR-amplified (12S rRNA for fish, COI for invertebrates, 16S for bacterioplankton, ITS for fungal pathogens), built into libraries and sequenced on Illumina MiSeq; a bioinformatic pipeline filters noise and matches reads against NCBI and BOLD reference databases.
3. Portable long-read field sequencing:
   • the Oxford Nanopore MinION reads long eDNA amplicons in real time on a laptop, enabling end-to-end off-grid metabarcoding from sample collection to species list directly at the waterbody.