Shark Bay stromatolites at risk from climate change

Stromatolites are among the most ancient records of life on earth. Ellie Gee

Climate change – resulting in more frequent flooding of the Wooramel River that leads into Shark Bay – may threaten the unique stromatolites that make Shark Bay a World Heritage site. These stromatolites – rocky structures formed over millennia by blue-green algae or cyanobacteria – thrive in Shark Bay’s Hamelin Pool, where an unusual undersea landscape has created an environment twice as saline as normal seawater.

Shark Bay was added to the World Heritage List in 1991 because of these stromatolites. They are living examples of the most ancient records of life on Earth.

But climate change is disturbing the natural system. The Wooramel River, which flows into Hamelin Pool, has flooded three times in the last year, washing in a huge amount of sediment and damaging Shark Bay’s seagrass meadows. Usually the river only floods every eight years or so.

Shark Bay (seen here during an algal bloom). NASA