A steady increase in ocean temperatures — nearly 3 degrees Fahrenheit in recent decades — was all it took to doom the once-luxuriant giant kelp forests of eastern Australia and Tasmania: Thick canopies that once covered much of the region’s coastal sea surface have wilted in intolerably warm and nutrient-poor water. Then, a warm-water sea urchin species moved in. Voracious grazers, the invaders have mowed down much of the remaining vegetation and, over vast areas, have formed what scientists call urchin barrens, bleak marine environments largely devoid of life.
A steady increase in ocean temperatures — nearly 3 degrees Fahrenheit in recent decades — was all it took to doom the once-luxuriant giant kelp forests of eastern Australia and Tasmania: Thick canopies that once covered much of the region’s coastal sea surface have wilted in intolerably warm and nutrient-poor water. Then, a warm-water sea urchin species moved in. Voracious grazers, the invaders have mowed down much of the remaining vegetation and, over vast areas, have formed what scientists call urchin barrens, bleak marine environments largely devoid of life.
Today, more than 95 percent of eastern Tasmania’s kelp forests — luxuriant marine environments that provide food and shelter for species at all levels of the food web — are gone. With the water still warming rapidly and the long-spine urchin spreading southward in the favorable conditions, researchers see little hope of saving the vanishing ecosystem.
“Our giant kelp forests are now a tiny fraction of their former glory,” says Craig Johnson, a researcher at the University of Tasmania’s Institute for Marine and Antarctic Studies. “This ecosystem used to be a major iconic feature of eastern Tasmania, and it no longer is.”
Read more at Yale Environment 360
Photo credit: Ed Bierman from Redwood City, USA via Wikimedia Commons
