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Fish can adjust to warmer ocean temperatures, but heat waves can still kill them, a team of researchers from Sweden, Norway and Australia reports in an article published this week in Nature Communications. 

"A species might adapt and grow well (in warmer waters) but once you get strong heat spells, the water temperature might reach lethal temperatures and kill them," said Fredrik Jutfelt, an associate professor in biology at the Norwegian University of Science and Technology who was senior author of the study.

Jutfelt and his colleagues studied European perch that live in a unique enclosed basin of warm water off the Swedish coast. The man-made basin, called the Forsmark Biotest Enclosure, was created three decades ago as a 1-km2 open-air laboratory by piping warm water from the nearby Forsmark nuclear power plant into an enclosed basin. 

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.

Un nuevo estudio dice que las emisiones de las granjas superan todas las demás fuentes humanas de contaminación del aire de partículas finas en gran parte de Estados Unidos, Europa, Rusia y China. El culpable: el humo de fertilizantes ricos en nitrógeno y residuos animales que se combinan en el aire con las emisiones industriales para formar partículas sólidas…una enorme fuente de enfermedad y muerte. La buena noticia: si disminuyen las emisiones industriales en las próximas décadas, como dicen la mayoría de las proyecciones, la contaminación de partículas finas bajará incluso si el uso de fertilizantes se duplica como se esperaba. El estudio aparece esta semana en la revista Geophysical Research Letters.

La contaminación agrícola del aire proviene principalmente en forma de amoniaco, que entra en el aire como un gas desde los campos altamente fertilizados y de desechos animales. A continuación, se combina con contaminantes procedentes de la combustión, principalmente óxidos de nitrógeno y sulfatos de los vehículos, plantas de energía y procesos industriales, para crear pequeñas partículas sólidas o aerosoles, de no más de 2,5 micrómetros de diámetro, alrededor de 1/30 del ancho de un cabello humano.

Las partículas pueden penetrar profundamente en los pulmones, provocando enfermedades al corazón o a los pulmones; un estudio del 2015 publicado en la revista Nature estima que causan al menos 3,3 millones de muertes cada año a nivel mundial.

El nuevo estudio no es el primero en señalar la contaminación agrícola; muchos estudios regionales, sobre todo en los Estados Unidos, han demostrado que es una fuente principal de precursores de partículas finas. 

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.

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.