Greek lake transparency thresholds were calibrated to biology instead of borrowed as generic cutoffs
WHAT THE EVIDENCE SAYS
Using 2013–2023 national monitoring data, researchers used binary logistic regression to calibrate Secchi-depth boundaries against phytoplankton and macrophyte ecological status for three lake types. The resulting thresholds were 0.6 m for very shallow lakes, 1.4–1.5 m for shallow lakes and 3.1 m for deep lakes, with moderate-to-good predictive performance.
WHY IT MATTERS / OUR READ
Simple field measurements become more useful when their thresholds are locally anchored to ecological response. The work is a good example of translating a cheap, repeatable indicator into a management boundary without pretending one universal Secchi depth fits every lake.
CAVEATS / UNCERTAINTY
The boundaries are specific to Greek natural-lake types and Water Framework Directive classification. They are statistical support thresholds, not universal ecological tipping points, and should be recalibrated before use in other limnological settings.
SOURCE
Hydrobiologia — primary study
View original evidence ↗
National monitoring from 19 lakes produced type-specific Secchi-depth boundaries linked to phytoplankton and macrophyte status.
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