Earthweek: a diary of the planet

Not so icy repose

Rapidly retreating Arctic sea ice has driven several hundred Pacific walrus to an Alaskan barrier island weeks earlier than ever observed. The marine mammals have historically conducted their “haul out” on sea ice, where they rest and feed. But they began showing up instead on Point Lay along the Chukchi Sea coast in 2007 as global warming melted their icy habitat. This year, they arrived two weeks before the previous earliest date in 2011. Up to 40,000 of the marine mammals have crowded onto the narrow island in recent years, putting them at risk of deadly stampedes.

Earthquakes

Two people were killed and dozens of others injured as a magnitude 4.2 earthquake struck a resort island off the coast of Naples, Italy, causing roofs to collapse and buildings to crumble. Earth movements also were felt in northeastern Iraq, northern India, New Zealand’s North Island, Guam, Hawaii and the Chilean capital of Santiago.

Early transplant troubles Researchers studying ways to detect early rejection of transplants in humans have uncovered a vast array of microbes in the human body previously unknown to science. Stephen Quake, Stanford University’s professor of bioengineering and applied physics, and colleagues made the discovery by looking at the cell-free DNA circulating in blood plasma. Of all the nonhuman DNA fragments that the team gathered, 99 percent failed to match anything in existing genetic databases that the researchers examined. Quake says most of the DNA fragments were from proteobacteria, which

includes such pathogens as E. coli and salmonella. Previously unknown viruses also were found.

Canadian invaders

The species of mosquito most responsible for the transmission of human Zika virus cases has been found for the first time in Canada. An adult Aedes aegypti mosquito was captured in a southern Ontario trap only a week after two Aedes albopictus mosquitoes, also known to transmit the virus, were found in the area. “Once they establish themselves here it would be more difficult to control, and maybe we’ll see some diseases we haven’t seen before,” medical official Wajid Ahmed said. It has long been predicted that climate change will result in expanding habitats for disease-carrying insects.

Blue dogs of Mumbai Untreated industrial waste dumped into greater Mumbai’s Kasadi River is blamed for a rash of blue dog sightings. India’s Hindustan Times reports that blue dye used to manufacture detergents is being absorbed by stray dogs that wade into the polluted water in search of food. One animal-care officer said the dye seems to be water-based and is not causing any ill effects for the canines, other than a blue tint in their fur, which washes out. Pollution control officials say the unnamed offending company also releases dye powder into the air, potentially threatening human health.

Storms

Sixteen people were killed when Category-2 Typhoon Hato lashed Hong Kong, Macau and China’s Guangdong province with wind gusts of up to 90 mph. A strengthening Hurricane Harvey was approaching the Texas coast late in the week. Hurricane Kenneth churned the Pacific west of Baja California.

Rainfall divide

Climate change is causing urban flooding to accelerate as the world’s countryside dries up, according to a new study published in the journal Scientific Reports. Researchers from the University of New South Wales made the discovery by analyzing data from rivers and rainfall gauges in 160 different countries. They found that a warmer climate is causing soil in rural landscapes to dry out more quickly, leaving it less likely to flood. But urban settings have far less soil, making them more and more prone to floods from the heavier downpours caused by a warmer and moister atmosphere.