Smithsonian.com

When I visited friends in Australia earlier this year, I made visiting the Great Barrier Reef a priority. When asked why, I responded: “I want to see it before it’s gone.” People thought I was joking.

I wasn’t.

Pollution, rising sea temperatures, ocean acidification, coral bleaching. One prediciton from the Intergovernmental Panel on Climate Change: the Great Barrier Reef could be a “functionally extinct” ecosystem by 2050. (My fellow travelers on the boat out to the reef were surprised to hear about these threats; they just expected a fun time.)

A new study in today’s issue of Science brings more bad news. Researchers from the Australian Institute of Marine Science analyzed the annual calcification rates of hundreds of massive Porites corals (like the one above) and found that their linear growth has declined by 13.3% since 1990. “The data suggest that such a severe and sudden decline in calcification is unprecedented in at least the past 400 years,” they write.

The researchers aren’t sure of the causes of the decline in growth but suspect that increasing temperature stress, declining pH and decreasing carbonate content are hindering the ability of the coral to calcify (i.e., add calcium carbonate to their skeletons and grow). They warn: “precipitous changes in the biodiversity and productivity of the world’s oceans may be imminent.”

Image courtesy of Jurgen Freund of Freund Factory