One litre of seawater, a hundred species: citizen scientists can now read the ocean in a bottle

You do not need to catch a fish to know it was there. Every creature sheds DNA into the water — and a single litre of seawater can hold traces of around 100 species. UNESCO has now rolled out its eDNA Expeditions programme worldwide, launched at the UN Biodiversity Conference in Yerevan: citizen scientists filter water samples, and labs read the genetic traces to map ocean life without removing a single animal. In the pilot, about 500 samples at 21 marine World Heritage sites identified more than 4,000 species — with collectors including children as young as six. The expansion targets 30 marine protected areas and some 3,000 samples by 2028.

SDG 14 · Life below water — Mechanism: institutional program