EARTHWEEK: DIARY OF A CHANGING WORLD
Areas of the world’s oceans, bays and lakes with little or no oxygen are dramatically expanding, according to a new study by the Smithsonian Environmental Research Center.
“The decline in ocean oxygen ranks among the most serious effects of human activities on the Earth’s environment,” said marine ecologist Denise Breitburg. About half of Earth’s oxygen comes from the oceans, and global warming is said to be the main cause of the decline. But in coastal dead zones, most of the oxygen depletion is caused by fertilizer and sewage runoff from land. Breitburg says reducing that runoff on a local level could go a long way to solving that problem.
Ozone hole healing
NASA has found the first direct evidence that the depletion of stratospheric ozone is slowing, allowing a sluggish but steady recovery of the ozone hole above Antarctica. The ozone layer protects life on the Earth’s surface from harmful solar radiation. The agency’s scientists say the 1989 international ban on the man-made chlorofluorocarbons responsible for most of the depletion now appears to be working. Those compounds were once widely used in aerosols, refrigerators and other appliances. But when leaked into the air, they can rise high into the stratosphere where they are broken down by ultraviolet radiation from the sun, releasing ozone-killing chlorine in the process.
One of the strongest of eight temblors that struck the IranIraq border region injured at least 21 people in western Iran.
• A rare tremor around the northern Dutch city of Groningen cracked buildings.
• Earth movements also were felt in the western Caribbean and northern Georgia.
At least 36 people were left dead in Madagascar after Category 2 Cyclone Ava raked the island’s east coast.
• Cyclone Irving churned the open waters of the central Indian Ocean as a threat only to shipping lanes.
A volcano on a remote Papua New Guinea island spewed ash for days during its first eruption in recorded history. Some of the 2,000 residents of Kadovar Island were forced to paddle to the nearby island of Blup Blup, while others were evacuated to other islands. But officials warned that a stronger eruption could also create a tsunami capable of striking nearby islands.
Fleas from domestic pets now infest wildlife and feral animals on all continents except Antarctica. A University of Queensland-led global study showed that socalled cat fleas — the main flea species found on domestic dogs and cats — are carried by more than 130 wildlife species around the world, representing nearly 20 percent of all the mammal species sampled. Dog fleas are less widespread and were reported on only 31 mammal species. The study warns that the fleas have the potential to transmit harmful bacteria back to pets and humans, including those that cause bubonic plague and typhus.
Areas around Sydney, Australia, experienced their hottest day in 79 years. The heat that baked three southeastern states also melted asphalt roadways, sparked dozens of fires and caused bats whose brains were said to have “fried” to fall dead from the trees. Australia just experienced its third-hottest year on record in 2017.
By Steve Newman