Earthweek: a Diary of the planet

A Canadian firm says it has unearthed the largest diamond ever found in North America in Canada’s Northwest Territories. Dominion Diamond Mines put its new 552-carat yellow diamond on display, saying it is also the seventhlargest diamond ever found on Earth. The company announced it will find a partner to cut and polish the stone in the coming weeks. The largest diamond ever found is the Cullinan, hich weighed 3,106.75 carats when unearthed in South Africa in 1905. Researchers have found that some bottlenose dolphins appear to make long-lasting friendships, form cliques and shun others outside their circle of trust. Writing in Marine Biology, the lead researcher said the team made the discovery during a nine-year study in the far northern Adriatic Sea. It revealed that each group was connected by several dolphins that acted as social brokers. Older, more experienced dolphins were found not to suffer social exclusion, possibly because they have long-term knowledge. Food waste from China’s expanding cities has become such a problem that firms are being encouraged to set up urban waste farms that use cockroaches to devour scraps. Reuters reports that one facility feeds food waste the equivalent in weight to seven adult elephants each day to a billion captive roaches. The bugs have the potential to provide nutrition for livestock once they die, and some say they could help combat stomach ailments and create beauty products. Residents of Indonesia’s northern Sulawesi Island fled in panic as Mount Soputan spewed lava, ash and smoke, forcing many to wear masks to keep from breathing in the ash.