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La idea de que la joven Tierra tenía una atmósfera más densa resulta ser incorrecta. Una nueva investigación de la Universidad de Washington utiliza burbujas atrapadas en las rocas con 2,7 00 millones años de edad, para mostrar que el aire en ese momento ejercía como máximo la mitad de la presión de la atmósfera de hoy.

SAR11, the most abundant plankton in the world's oceans, are pumping out massive amounts of two sulfur gases that play important roles in the Earth's atmosphere, researchers announced today in the journal Nature Microbiology.

Most living organisms adapt their behavior to the rhythm of day and night. Plants are no exception: flowers open in the morning, some tree leaves close during the night. Researchers have been studying the day and night cycle in plants for a long time: Linnaeus observed that flowers in a dark cellar continued to open and close, and Darwin recorded the overnight movement of plant leaves and stalks and called it "sleep". But even to this day, such studies have only been done with small plants grown in pots, and nobody knew whether trees sleep as well. Now, a team of researchers from Austria, Finland and Hungary measured the sleep movement of fully grown trees using a time series of laser scanning point clouds consisting of millions of points each.

A new study says that emissions from farms outweigh all other human sources of fine-particulate air pollution in much of the United States, Europe, Russia and China. The culprit: fumes from nitrogen-rich fertilizers and animal waste that combine in the air with industrial emissions to form solid particles—a huge source of disease and death. The good news: if industrial emissions decline in coming decades, as most projections say, fine-particle pollution will go down even if fertilizer use doubles as expected. The study appears this week in the journal Geophysical Research Letters.

Agricultural air pollution comes mainly in the form of ammonia, which enters the air as a gas from heavily fertilized fields and livestock waste. It then combines with pollutants from combustion—mainly nitrogen oxides and sulfates from vehicles, power plants and industrial processes—to create tiny solid particles, or aerosols, no more than 2.5 micrometers across, about 1/30 the width of a human hair. The particles can penetrate deep into lungs, causing heart or pulmonary disease; a 2015 study in the journal Nature estimates they cause at least 3.3 million deaths each year globally.

As climatologists closely monitor the impact of human activity on the world's oceans, researchers at the Georgia Institute of Technology have found yet another worrying trend impacting the health of the Pacific Ocean.

A new modeling study conducted by researchers in Georgia Tech's School of Earth and Atmospheric Sciences shows that for decades, air pollution drifting from East Asia out over the world's largest ocean has kicked off a chain reaction that contributed to oxygen levels falling in tropical waters thousands of miles away.

"There's a growing awareness that oxygen levels in the ocean may be changing over time," said Taka Ito, an associate professor at Georgia Tech. "One reason for that is the warming environment -- warm water holds less gas. But in the tropical Pacific, the oxygen level has been falling at a much faster rate than the temperature change can explain."

The study, which was published May 16 in Nature Geoscience, was sponsored by the National Science Foundation, a Georgia Power Faculty Scholar Chair and a Cullen-Peck Faculty Fellowship.

In the report, the researchers describe how air pollution from industrial activities had raised levels of iron and nitrogen -- key nutrients for marine life -- in the ocean off the coast of East Asia. Ocean currents then carried the nutrients to tropical regions, where they were consumed by photosynthesizing phytoplankton.