Home / Services / Assess Freshwater Health
Service 02 · Diatom assessment & ecological status
Assess Freshwater Health.
Leverage the unparalleled sensitivity of diatoms, freshwater’s most reliable ecological indicators, to assess river and lake health at catchment scale. Rigorous metrics, fast turnaround, WFD-aligned reporting.
£275 (discounts available)
4–6 weeks
EIA and WFD monitoring
Why diatoms?
Tiny organisms. Powerful indicators.
Diatoms are microscopic algae encased in intricate silica shells, and they are among the most sensitive biological indicators of water quality available to freshwater scientists. They respond rapidly and predictably to changes in nutrient levels, pH, conductivity, and organic enrichment.
Historically, diatom analysis required expert microscopy which is time-consuming, expensive, and limited. eDNA sequencing changes this entirely, allowing us to identify and quantify diatom communities from a simple water sample at a fraction of the cost and time.
Our approach
eDNA sequencing meets established metrics.
We sequence the rBCL gene region to characterise diatom communities, then apply the Trophic Diatom Index (TDI), Specific Pollution Sensitivity Index (SPI), and Biological Water Quality Class (BWQC) to deliver actionable ecological status scores.
Step A
Collect
Our simple kits contain everything you need to collect diatom samples from your sites and preserve them for transport. An alkalinity strip is included, to test the alkalinity of the surrounding water, which feeds into your results.
Step B
Sequence
Once we have received your samples, we will process them in the lab, using rBCL barcoding to assess diatom species composition. This tells us whether a diatom community is made up of species that require good water quality vs species that are more pollution-tolerant.
Step C
Understand
Using the sequencing results, we calculate the Trophic Diatom Index (TDI) and Specific Pollution Sensitivity Index (SPI) per site and across networks. Outputs are then mapped to Water Framework Directive (WFD) classes, providing insights into water quality.
Step D
Monitor
Results and future sampling plans can be scaled temporally or geographically to detect change over time and space, ideal for impact monitoring and land management.
Use cases
Who uses diatom assessment.
Water companies
WFD compliance monitoring and ecological impact assessment for abstraction, discharge, and infrastructure projects.
Environment Agency & NRW
Regulatory status reporting and compliance monitoring across water body networks at scale.
River trusts & NGOs
Before-and-after monitoring for river restoration, quantifying ecological recovery and demonstrating impact to funders.
Ecological consultancies
Rapid assessment of freshwater ecological status for planning applications, EIA surveys, and SSSI management.
Researchers
Long-term monitoring datasets and catchment-scale diatom community surveys for academic research programmes.
What you receive
Clear status scores. Actionable findings.
Sampling kit
Simple collection. No expertise needed.
Our diatom kit simplifies sampling with a bamboo brush and collection vial, clear illustrated instructions, and preservation reagents that stabilise samples for postal return. No cold chain required.
Designed for non-specialists. Catchment scientists, volunteers, and field officers can all collect valid samples confidently.
Frequently asked
Your questions, answered.
Is eDNA diatom assessment accepted for WFD reporting?+
We are working closely with regulators to achieve formal acceptance. Currently we recommend eDNA assessment alongside or instead of traditional methods depending on the specific regulatory context.
How do your results compare to traditional microscopy?+
Multiple peer-reviewed studies show strong concordance between eDNA metabarcoding and traditional microscopy. Metabarcoding typically detects a broader range of taxa.
What season is best for diatom sampling?+
Spring and autumn are optimal for most UK freshwater systems. We can advise on sampling windows for your specific catchment.
Can I combine this with bacterial source tracking?+
Yes. Many clients run multiple services simultaneously. However, these services require separate collection kits. Reach out to us for advice on how to best combine services in your sampling plan.
How much does it cost?+
Pricing starts at £275 per sample with discounts for larger programmes. Book a free consultation for a transparent quote.
Start a project
What is the ecological
status of your catchment?
Book a 30-minute consultation. We’ll discuss your monitoring objectives, design a sampling programme, and send a no-obligation quote.