Stirling University researchers believe they hold the key to making the Black Sea blue again. The inland sea – named Pontus Axeinus, or “Inhospitable Sea” – by the ancient Greeks, is reputedly where Jason and the Argonauts set out to find the golden fleece. Today the inshore waters, shared by eight nations from Turkey to Russia and Bulgaria to Georgia, are the subject of major concern over pollution levels so high that it’s considered the world’s most contaminated sea. It holds double the level of marine litter found in the Mediterranean and suffers from extensive eutrophication – high levels of phosphorus, nitrogen, and other plant nutrients. The poor water quality has had a serious impact on fish stocks and species diversity is under severe threat.