Millions - Possibly 10s Of Millions - Of Sea Sponges Bleach Off South Island Of New Zealand
New Zealand is experiencing the largest bleaching of sea sponges ever recorded, scientists say, after extreme ocean temperatures turned millions of the aquatic creatures white. The discovery comes after researchers raised the alarm in May, when sea sponges off New Zealand’s southern coastline were found bleached for the first time.
Initially, researchers estimated hundreds of thousands of the sponges had been bleached – but over the past month, scientists conducted investigations at coastlines around the country, and found that millions – possibly tens of millions – had been transformed bone-white. “As far as we’re aware, it’s the largest scale and largest number of sponges bleached in one event that’s been reported anywhere in the world … certainly in cold waters,” said Victoria University marine ecologist Prof James Bell.
When members of Bell’s team first spotted the May bleaching event in Fiordland, they put the word out to the department of conservation and other charter vessels around the region to see if it had been spotted in other Sounds. “They pretty much reported the bleaching everywhere they went,” he said. The team now believes “there are at least millions of sponges, maybe many millions of sponges that have undergone this bleaching”.
Sea sponges, like coral, rely on symbiotic organisms that photosynthesise inside them, providing food for the sponge and sometimes deterring predators. While bleaching does not necessarily kill the sponges outright, it evicts those organisms – lowering the chemical defences of the sponges and depriving them of food. While some species can recover from severe bleaching, Bell said others do not.
EDIT
https://www.theguardian.com/world/2022/jun/23/new-zealand-records-largest-ever-bleaching-of-sea-sponges
= new reply since forum marked as read
