An underwater forest of kelp sitting off the coast of Australia is suffering the effects of a marine heatwave. These conditions are seriously affecting the delicate marine ecosystem in the region, researchers concluded.
A stretch of more than 60 miles of kelp were destroyed by the warmer conditions, which ravaged waters in the area in 2011. The marine environment off the coast of western Australia at that time averaged 35.6 degrees Fahrenheit above normal, conditions that lasted 10 weeks, seriously damaging underwater kelp fields.
As higher water temperatures killed off large quantities of kelp, the marine vegetation was replaced by tropical and subtropical species. Five years after the heatwave, this damage shows no sign of abating. The Leeuwin Current, which flows southward, is one factor hindering the recolonization of damaged areas by kelp. Invasive animal species are also grazing upon the kelp, hindering any recovery.
Damage from the heatwave extends more than 620 miles, but the greatest impact was felt in an area roughly one-tenth that size. In that region, the heatwave killed off kelp over an area of nearly 150 square miles. Further south, roughly 370 square miles of kelp have been lost to warmer water.
The Great Southern Reef (GSR), stretching more than 5,000 miles along the southern coast of Australia, is greatly affected by damage from the recent heatwave. In western areas of that region, the kelp forest is migrating toward the coast of the island continent, where warmer conditions increase damage to the local environment.
"Kelp forests are the GSR's 'biological engine,' feeding a globally unique collection of temperate marine species, not to mention supporting some of the most valuable fisheries in Australia and underpinning reef tourism worth more than A$10 billion a year," The Conversation reports.
Researchers examined kelp fields, corals, seaweeds, invertebrates and fish between 2001 and 2015, in an effort to determine how marine populations were changing over time. Investigators found 43 percent of kelp forests were lost following the heatwave.
Regions located closer to the natural habitats of tropical and subtropical species were affected by invasion of alien species to a greater degree than location further from such areas.
The area is experiencing a rate of rising marine temperatures roughly twice the global average. This effect provides a glimpse of how global warming will alter climate around the world over the coming decades.
Analysis of how the marine heatwave of 2011 is affecting kelp fields in waters near Australia was published in the journal Science.