Diatoms and Diatom Teratology
Scrape periphytic diatoms from 5 submerged stones into a sample vial for slide preparation.
Why this matters — One Health
Certain diatom species can form harmful algal blooms (HABs) in freshwater environments. These blooms can produce toxins and/or deplete oxygen levels in the water, harm aquatic organisms, leading to fish kills and posing risks to human health through contaminated water or food consumption.
Source: Importance of indicator — I. Diatoms and diatom teratology (factsheet_text.txt)
Collection Protocol
Scrape periphytic diatoms from submerged stones into sample vial. Clean with nitric acid and potassium dichromate. Prepare permanent slides using Naphrax®.
Laboratory Protocol Required
Requires nitric acid / potassium dichromate oxidation, resin mounting (Naphrax®), and microscopic valve identification (~400 valves) under 1000x magnification (EN 13942).
You cannot determine the result in the field.
Deterministic assessment
Awaiting laboratory analysis- ObservationField record contains sample ID, collection protocol and notes only — no measurement.
input/DIA-10/sample - RuleOfficial measurement (factsheet §I): periphyton is scraped, cleaned and mounted; about 400 diatom valves are identified and counted to species level; biotic indices (IBD, IPS) and teratology counts produce the biological quality status.
DIA-10/lab-pending - SourcesFactsheet §I (Diatoms): "About 400 diatom valves are identified and counted per sample, following the European standard"; "Common biotic indices … are the Biological Diatom Index (IBD) … and the Indice de Polluosensibilité (IPS)" (OneAquaHealth Key Indicators Factsheets, doi:10.5281/zenodo.20345207).
source/factsheet/DIA-10
- !We do not grade what we did not measure: index reference values are river-type specific and member-state adopted (factsheet §I), so no index can be computed before laboratory identification.
Deterministic rules (streamvitals-assessment/1.0.0). No AI, no network, no hidden state.