Great Southern Reef In Australia Devastated By Marine Heat Wave

At least one hundred kilometers (more than 62 miles) of kelp forests in Australia’s Great Southern Reef have been wiped out by a marine heat wave that occurred between 2010 and 2013, according to a new study published in the journal Science. Nearly 90 percent of the kelp forests found off of the northwestern tip of the Great Southern Reef in Australia have disappeared and have already been replaced by corals, coral fish, and seaweed turfs that are typically only seen in tropical or subtropical ocean environments.

The Great Southern Reef runs more than 2,300 kilometers (nearly 1,430 miles) along Australia’s southern coast, but the reef system also extends past Sydney on the east coast, down to Tasmania, then back up to Kalbarri on the west coast, reported The Guardian.

“It supports most of the nation’s fisheries, including the lucrative rock lobster and abalone fisheries, and is worth about $10 billion to the Australian economy.”

The entire system of rocky reefs covered by kelp forests that make up the Great Southern Reef of Australia is an important part of global biodiversity, since the region has about 30 percent of species that are endemic to the region. Organisms that are endemic cannot exist elsewhere and are defined to a specific geographic location with unique environmental conditions, such as Australia’s Great Southern Reef.

The lead study author, Dr. Thomas Wernberg of the University of Western Australia’s Oceans Institute, told The Guardian that a marine heat wave characterized by ocean temperatures that rose just two degrees Celsius caused the kelp forest to die. This in turn led to the functional extinction of 370 square kilometers (more than 229 square miles) of rocky cool-climate reefs along the Great Southern Reef.

According to Wernberg, if this marine heat wave continues, the kelp forests could ultimately retract to the southernmost tip of Western Australia, setting off a chain of events that would be just as environmentally and economically devastating as the loss of Australia’s Great Barrier Reef.

“I think the next big heat wave is just going to push what we see in the north ultimately further down, and then it just depends on how bad that heat wave is,” Wernberg stated. “All the projections are that it will get warmer, we will get more frequent heat waves, so unfortunately I think it’s just a matter of time.”

Wernberg, and fellow researcher Dr. Scott Bennett, told The Atlantic that they were shocked when they dove into the water and saw firsthand the devastation caused in the area by the massive marine heat wave.

“We thought we were in the wrong spot. It was like someone had bulldozed the reef. It was like a moonscape underwater – scummy, brown and empty.”

According to the report, climate change is responsible for the recent devastation that’s happened to the Great Southern Reef in Australia, where the ocean waters are among the fastest-warming regions worldwide and a series of extreme heat waves have pummeled the area in recent years. For example, the study shows that in the summer of 2011, the heat wave soared to reach highs that have not been seen in 215 years of record keeping, which were far beyond what kelp, which prefers milder conditions, could tolerate.

“It was just heartbreaking,” Bennett stated. “It really brought home to me the impact that climate change can have on these ecosystems, right under our noses.”

Most people probably think of the Great Barrier Reef first when the words “reef” and “Australia” show up anywhere together, but unfortunately this other magical underwater world of colorful corals is not faring much better than the kelp forests of the nation’s Great Southern Reef. Located off of Australia’s eastern coast, the Great Barrier Reef is under duress from a catastrophic bleaching event, which is wreaking havoc and has scientists scrambling to stop it from spreading.

“The reason we haven’t heard a ton about kelp and climate change in the popular press is because they are the rock stars of marine resilience,” Jarrett Byrnes from the University of Massachusetts Boston told The Atlantic, in response to questions about why the devastation in Australia’s Great Southern Reef isn’t getting more attention. “If kelps don’t bounce back from a big disturbance after a few years, you know something is deeply wrong.”

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