FYI.

This story is over 5 years old.

Tech

Humans Have Been Wrecking the Great Barrier Reef for Longer Than We Thought

The world's largest reef has farmers to blame for its decline.

The Great Barrier Reef off the coast of Australia is so bad-ass it can be seen from space, but it’s been on the decline throughout the last century. And like with the nearly-dead reefs of the Caribbean, humans are to blame.

Specifically, a new study suggests that the rise of European settlement in Australia starting in the mid-19th century led to a coral die-off before we started worrying about things like reef tourism and climate change. The study, published in Proceedings of the Royal Society B, shows that a mass migration to Queensland, Australia created a farming boom that led to a significant increase in water pollution from around 1920-1960.

Advertisement

The research team from the University of Queensland Australia took core samples of seafloor sediment around Pelorus Island off the coast of Queensland to see if the coral composition changed throughout the last couple centuries. They found that, before colonization, the reef was predominantly housed by Acropora coral, which grows quickly and can measure 16 feet high and 65 feet across. Those massive coral are key to the development of the huge Great Barrier Reef and its incredible biodiversity.

But according to the team, sometime between 1920 and 1960 the Acropora gave way to coral from the Pavona family, which is slower-growing and less spacious. That correlates with an increase in agricultural and pesticide runoff that exploded as settlers chopped down Queensland forests and turned them into sheep farms and sugar plantations. The result is a reef system that’s less resilient, that makes for a worse storm buffer, and that’s less able to harbor a strong, diverse ecosystem.

“Corals have always died from natural events such as floods and cyclones, but historically have shown rapid recovery following disturbance. Our results suggest that the chronic influence of European settlement on the Queensland coastline may have reduced the corals ability to bounce back from these natural disturbances," lead author George Roff said in a release.

Roff sums up the issue well: the cloudy, polluted waters off Queensland have depressed the health of the reef system for more than 50 years, which is only setting the reef up for a worse decline as waters warm. There’s one spot of good news though: according to the team, the reefs are likely to recover if water quality improves. So hey, let’s cut down on that polluted runoff.

Image: Anthony Johnson, Getty Images

Follow Derek Mead on Twitter: @derektmead.