The deaths of 5,000 sheep this spring remain an enigma. Photo: Sigurður Bogi Sævarsson

Some 5,000 sheep died this spring in Iceland in baffling circumstances. The latest theory is that the deaths were caused by sulphur released by the Holuhraun volcanic eruption.

The unexplained deaths, hitting West and North Iceland worst, remain an enigma. According to Jónas Elíasson, Professor of Engineering at the University of Iceland, the answer could be digestive complications caused by ingesting volcanic sulphur.

“When the ash cloud moves over the country from the east, it is often accompanied by rain,” explains Elíasson. “The rain cleans the sulphur out of the air and snow does the job even better. When the snow melts in the spring, the sulphur remains on vegetation and in the soil.”

Ewes are particularly vulnerable during the spring lambing season and sulphur can disrupt their digestive system, leading to malnutrition and starving to death.

Elíasson explains that an in-depth study of correlation between the sheep deaths and sulphur precipitation is possible.

Other suggested causes for the unexplained deaths include the cold weather and poor-quality feed.