#coorong

Mouth of the Murray

The Coorong is a system of saline lagoons that stretches for 130 kilometres along the coast of South Australia, south of Adelaide. At the far western end of Coorong National Park, the Murray River flows into the south-eastern Indian Ocean. This end of the park is very popular for fishing, boating and bird-watching, because the Coorong, along with Lakes Alexandrina and Albert, is part of an internationally-recognised wetland. This wetland provides habitat for over 200 bird species, including the Australian Pelican and the critically endangered Orange Bellied Parrot. Many visitors also enjoy four wheel driving among the coastal sand dunes that lie further south in the park, which separate the Coorong lagoons from the sea.

The Coorong has been the subject of numerous research studies over the past few decades, mostly because of a mineral called dolomite (CaMg(CO3)2). Although dolomite is relatively common in rocks from earlier times in Earth’s history, there are very few places where it forms today. Why? Scientists don’t know yet – it’s often referred to as the ‘dolomite problem’. Some studies have suggested that dolomite forms here because of the alkaline, magnesium-rich waters of the lagoons, whereas others have found that sulfate-reducing bacteria may play an important role in dolomite precipitation. Either way, researchers hope that eventually, these studies in the Coorong will lead to a solution to this intriguing question.

-EH