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Climate change is causing Antarctica's snow to turn green, study says - CBS News
As the climate warms, scientists expect more and more of the snowy desert to turn bright green.
In coastal Antarctica, some snow isn't white — it's green. And while small amounts of the green snow have been visible for years, it's starting to spread across the continent because of climate change. According to a study published Wednesday in the journal Nature Communications, the vibrant color is caused by microscopic algae blooming across the surface of the snow. Using satellite data and fieldwork observations, a team of researchers at the University of Cambridge and the British Antarctic Survey have created the first large-scale map of the green algae and predicted the future spread of the bizarre snow. Green snow appears along the Antarctic coast, growing in "warmer" areas, where the average temperatures reach just above freezing in the summer. Although the individual algae are microscopic, when they grow at scale, the green snow can even be seen from space. For the study, the team combined on-the-ground research from two summers in the Antarctic Peninsula with images from the European Space Agency's Sentinel 2 satellite taken between 2017 and 2019. In total, the team identified over 1,600 separate algal blooms on the snow surface. Lead author Matt Davey samples snow algae on Lagoon Island, Antarctica. Sarah Vincent The team found that the distribution of green snow algae is strongly influenced by marine birds and mammals, because their excrement works extremely well as fertilizer. Over 60% of blooms were found near penguin colonies, and others were found near birds' nesting sites. "This is a significant advance in our understanding of land-based life on Antarctica, and how it might change in the coming years as the climate warms," lead author Dr. Matt Davey of the University of Cambridge said in a press release. If bird populations are strongly affected by climate change, as they likely will be, the algae could lose key sources of nutrients. But the results of the study indicate that green snow will massively spread as global temperatures rise. That's because in order to flourish, the organisms need an available supply of water. Temperatures on the peninsula where the green snow is found have risen dramatically in recent decades, increasing the amount of water available. As the planet warms and more of Antarctica's snow melts, the algae will spread, the scientists said. And while some algae will be lost to areas that lose snow altogether, much more will be gained. A photograph showing Anchorage Island dominated by green algae starting to melt out from beneath surface snow on January 26, 2018. Nature Communications "As Antarctica warms, we predict the overall mass of snow algae will increase, as the spread to higher ground will significantly outweigh the loss of small island patches of algae," said co-lead author Dr. Andrew Gray, of the University of Cambridge and the University of Edinburgh. It's unclear how the spreading algae will affect the planet. It plays a key role in cycling nutrients and pulling carbon dioxide from the atmosphere through photosynthesis, Davey said, but also darkens snow, and absorbs more heat from the sun. The amount of algae found by the team creates a carbon sink that absorbs about 500 tons of carbon each year, the equivalent of about 875,000 average car journeys in the U.K., researchers said. The amount of algae found is actually a conservative estimate, because the satellite was only capable of picking up green algae, missing its red and orange counterparts. "The snow is multi-colored in places, with a palette of reds, oranges and greens — it's quite an amazing sight," Davey said.
Stunning image of a cosmic spiral reveals what could be first glimpse at the birth of a planet - CBS News
A bright spiral marks the spot where scientists believe a planet may be coming into existence.
Astronomers have found thousands of exoplanets lurking within the distant cosmos, but they know very little about their origins. Now, a dramatic new image could be offering a rare glimpse into one of the most mysterious processes in the universe: the birth of a new planet. Using the European Southern Observatory's Very Large Telescope (ESO's VLT), researchers spotted a glowing orange spiral with a "twist" marking the spot where they believe a planet may be forming. According to a study published Wednesday in the journal Astronomy & Astrophysics, it would be the first direct evidence of a planet coming into existence. "Thousands of exoplanets have been identified so far, but little is known about how they form," lead author Anthony Boccaletti, of the Observatoire de Paris at PSL University in France, said in a press release. "We need to observe very young systems to really capture the moment when planets form," he said. Astronomers observed the possible baby planet forming a spiral of dust and gas around a young star known as AB Aurigae, located 520 light years away from Earth in the constellation Auriga. Scientists know planets form as cold gas and dust collide with one another around stars over billions of years, but these new observations provide crucial data to paint a clearer picture of the process. This image shows the disc around the young AB Aurigae star, where ESO's Very Large Telescope has spotted signs of planet birth. The image was obtained with the VLT's SPHERE instrument in polarised light. ESO/Boccaletti et al. Researchers have been studying the star system for years using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. But until now, they have have been unable to capture clear images of this process in order to find the all-important "twist" that identifies the birth of a planet. The deepest images of the system to date, taken using the SPHERE instrument on the VLT, show a stunning swirl around AB Aurigae, signaling the presence of a baby planet "twisting, swirling and "kicking" to create "disturbances in the disc in the form of a wave, somewhat like the wake of a boat on a lake," said co-author Emmanuel Di Folco of the Astrophysics Laboratory of Bordeaux (LAB) in France. The spiral is created as the planet rotates around the central star. Based on predicted models, the team believes the planet is forming in the very bright yellow "twist" region close to the center of the image, which is located at about the same distance from its star as Neptune is from the sun. Zooming in to AB Aurigae by European Southern Observatory (ESO) on YouTube "The twist is expected from some theoretical models of planet formation," said co-author Anne Dutrey, also at LAB. "It corresponds to the connection of two spirals — one winding inwards of the planet's orbit, the other expanding outwards — which join at the planet location. They allow gas and dust from the disc to accrete onto the forming planet and make it grow." Astronomers hope to get an even clearer picture of the growing planet after the completion of ESO's Extremely Large Telescope, which will become "the world's biggest eye on the sky," in 2025.