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How the chicxulub impactor gave rise to modern rainforests – Science Daily

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Tropical rainforests today are biodiversity hotspots and play an important role in the world’s climate systems. A new study published today in Science sheds light on the origins of modern rainforests and may help scientists understand how rainforests will respond to a rapidly changing climate in the future.

The study led by researchers at the Smithsonian Tropical Research Institute (STRI) shows that the asteroid impact that ended the reign of dinosaurs 66 million years ago also caused 45% of plants in what is now Colombia to go extinct, and it made way for the reign of flowering plants in modern tropical rainforests.

“We wondered how tropical rainforests changed after a drastic ecological perturbation such as the Chicxulub impact, so we looked for tropical plant fossils,” said Mónica Carvalho, first author and joint postdoctoral fellow at STRI and at the Universidad del Rosario in Colombia. “Our team examined over 50,000 fossil pollen records and more than 6,000 leaf fossils from before and after the impact.”

In Central and South America, geologists hustle to find fossils exposed by road cuts and mines before heavy rains wash them away and the jungle hides them again. Before this study, little was known about the effect of this extinction on the evolution of flowering plants that now dominate the American tropics.

Carlos Jaramillo, staff paleontologist at STRI and his team, mostly STRI fellows — many of them from Colombia — studied pollen grains from 39 sites that include rock outcrops and cores drilled for oil exploration in Colombia, to paint a big, regional picture of forests before and after the impact. Pollen and spores obtained from rocks older than the impact show that rainforests were equally dominated by ferns and flowering plants. Conifers, such as relatives of the of the Kauri pine and Norfolk Island pine, sold in supermarkets at Christmas time (Araucariaceae), were common and cast their shadows over dinosaur trails. After the impact, conifers disappeared almost completely from the New World tropics, and flowering plants took over. Plant diversity did not recover for around 10 million years after the impact.

Leaf fossils told the team much about the past climate and local environment. Carvalho and Fabiany Herrera, postdoctoral research associate at the Negaunee Institute for Conservation Science and Action at the Chicago Botanic Garden, led the study of over 6,000 specimens. Working with Scott Wing at the Smithsonian’s National Museum of Natural History and others, the team found evidence that pre-impact tropical forest trees were spaced far apart, allowing light to reach the forest floor. Within 10 million years post-impact, some tropical forests were dense, like those of today, where leaves of trees and vines cast deep shade on the smaller trees, bushes and herbaceous plants below. The sparser canopies of the pre-impact forests, with fewer flowering plants, would have moved less soil water into the atmosphere than did those that grew up in the millions of years afterward.

“It was just as rainy back in the Cretaceous, but the forests worked differently.” Carvalho said.

The team found no evidence of legume trees before the extinction event, but afterward there was a great diversity and abundance of legume leaves and pods. Today, legumes are a dominant family in tropical rainforests, and through associations with bacteria, take nitrogen from the air and turn it into fertilizer for the soil. The rise of legumes would have dramatically affected the nitrogen cycle.

Carvalho also worked with Conrad Labandeira at the Smithsonian’s National Museum of Natural History to study insect damage on the leaf fossils.

“Insect damage on plants can reveal in the microcosm of a single leaf or the expanse of a plant community, the base of the trophic structure in a tropical forest,” Labandeira said. “The energy residing in the mass of plant tissues that is transmitted up the food chain — ultimately to the boas, eagles and jaguars — starts with the insects that skeletonize, chew, pierce and suck, mine, gall and bore through plant tissues. The evidence for this consumer food chain begins with all the diverse, intensive and fascinating ways that insects consume plants.”

“Before the impact, we see that different types of plants have different damage: feeding was host-specific,” Carvalho said. “After the impact, we find the same kinds of damage on almost every plant, meaning that feeding was much more generalistic.”

How did the after effects of the impact transform sparse, conifer-rich tropical forests of the dinosaur age into the rainforests of today — towering trees dotted with yellow, purple and pink blossoms, dripping with orchids? Based on evidence from both pollen and leaves, the team proposes three explanations for the change, all of which may be correct. One idea is that dinosaurs kept pre-impact forests open by feeding and moving through the landscape. A second explanation is that falling ash from the impact enriched soils throughout the tropics, giving an advantage to the faster-growing flowering plants. The third explanation is that preferential extinction of conifer species created an opportunity for flowering plants to take over the tropics.

“Our study follows a simple question: How do tropical rainforests evolve?” Carvalho said. “The lesson learned here is that under rapid disturbances — geologically speaking — tropical ecosystems do not just bounce back; they are replaced, and the process takes a really long time.”

The Smithsonian Tropical Research Institute, headquartered in Panama City, Panama, is a unit of the Smithsonian Institution. The institute furthers the understanding of tropical biodiversity and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems.

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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