Earthweek: a diary of the planet

For the week ending Friday, Jan. 21.

Air hazards

Smog and smoke clouds that frequently plague California and other parts of the West are making breathing more dangerous for residents, a study finds. Researchers at Washington State University in Vancouver found that exposure to ground-level ozone and the fine-particle pollution from more frequent wildfires has increased by 25 million “person days” from 2001 to 2020. Short-term effects from the pollution include breathing difficulties and worsening heart and lung diseases, such as asthma. Exposure to both types of pollution at the same time compounds the health risks, and long-term exposure can have far more serious consequences.

Manatee deaths

A record number of Florida’s protected manatees died in 2021, with the 1,101 deaths more than double the five-year average. Most were along the state’s eastern coast, where pollution-fed algae blooms were the main cause. The blooms are responsible for wiping out thousands of acres of seagrass in the Indian River Lagoon, a major feeding area for manatees.

Mass extinction

Earth’s sixth mass extinction is accelerating, and a study points out that it is the only one in the planet’s history to be caused by human activity. “Drastically increased rates of species extinctions and declining abundances of many animal and plant populations are well documented, yet some deny that these phenomena amount to mass extinction,” said lead researcher Robert Cowie. Writing in Biological Reviews, he and his colleagues estimate that 7.5% to 13% of Earth’s 2 million known species may already be lost.

Breeding seabed

Scientists say they have discovered the world’s largest fish-breeding area, located in the south of Antarctica’s Weddell Sea. Trolling with underwater cameras, they captured images of thousands of Jonah’s icefish nests on the seabed, with a density of about one nest per 30 square feet, which suggests about 60 million breeding sites blanket the seabed. “Finding an assemblage on this scale is just mind-blowing to me,” said British Antarctic Survey scientist Katrin Linse, who had wondered where the icefish breed during an earlier expedition about 25 years ago.

Volcanic blast

The most powerful volcanic blast anywhere on the planet for more than 30 years was heard thousands of miles away and created a humanitarian disaster in nearby Tonga. Tsunamis from the Hunga Tonga volcano blast rushed across the Pacific as barometers worldwide recorded the force of the explosion. The ocean surges also caused “significant damage” in Tonga as falling ash poisoned the landscape, including the rainwater supplies that most Tongans collect on their roofs. It is feared that ash-filled waters offshore will deprive fish of food and spawning beds, threatening the livelihoods of fishermen.