Connect with us


Bumble bee numbers tumble with climate change: study – FRANCE 24



Issued on: 07/02/2020 – 19:36Modified: 07/02/2020 – 19:35


Paris (AFP)

Climate change has contributed to a sharp drop in bumble bee populations across North America and Europe in recent decades, scientists said Friday.

Compared to the period 1900-1974, bumble bee numbers across dozens of distinct species dropped, on average, 46 percent during the first 15 years of the 21st century in Canada and the United States.

In Europe, the corresponding decline of the pollinators was 17 percent, they reported in the journal Science.

Many species of bees and other insects are in a downward spiral, previous research has shown.

Nearly half of all insect species worldwide are in decline and a third could disappear altogether by century’s end, scientists concluded last year in a landmark study, warning about dire consequences for crop pollination and natural food chains.

But the main drivers of extinction are thought to be habitat loss and pesticide use, and teasing out the possible impact of climate change — a more recent threat — “has proven exceptionally challenging,” researchers led by Peter Soroye, a biologist at the University of Ottawa, said in the new study.

To get around that problem, the scientists analysed more than half-a-million geo-localised bumble bee sightings mapped onto a 100-km2 grid in each continent.

They analysed population changes over time in each grid and matched those to average increases or decreases in temperature, as well as heat peaks beyond the threshold of bumble bee tolerance.

As expected, areas most affected by global warming showed the most acute declines in bumble bee density, while populations rose in regions that had previously been too cool for the bees to thrive.

But the numbers did not offset each other — even after taking into account the new bee colonies in cooler climes, total population were way down.

The results, the scientists concluded, “suggest that recent climate change has driven stronger and more widespread bumble bee declines than have been reported previously.

“Climate change-related local extinction among species greatly exceeded those of colonisation, contributing to pronounced bumble bee species decline across both Europe and North America.”

Insects are the world’s top pollinators — 75 percent of 115 top global food crops depend on animal pollination, including cocoa, coffee, almonds and cherries, according to the UN.

One-in-six species of bees have gone regionally extinct somewhere in the world.

Let’s block ads! (Why?)

Source link

Continue Reading


Meteor Showers Taking Place Thursday and Friday Night –



A meteor shower you won’t want to miss.

Gary Boyle, The Backyard Astronomer, tells us we are currently passing through the dusty debris of Comet 109P/Swift-Tuttle.

It last appeared in 1992, and will return again in 2125.

He said the shower is lasting all night long, but 2 a.m. would be the time to see the most meteor.

The Backyard Astronomer suggested keeping an eye out for other things in the sky, as well.

Boyle added the next large shower will be in mid-December, but this one might be a little warmer to sit outside and watch.

Written by Ashley Taylor

Adblock test (Why?)

Source link

Continue Reading


New long-necked dinosaur helps rewrite evolutionary history of sauropods in South America – University of Michigan News



Panoramic view of the Serranía del Perijá in Colombia, where a vertebra was found in 1943. The vertebra has allowed for scientists to identify a new species of sauropod, the Perijasaurus lapaz. Image credit: Jeff Wilson Mantilla, University of Michigan

A medium-sized sauropod dinosaur inhabited the tropical lowland forested area of the Serranía del Perijá in northern Colombia approximately 175 million years ago, according to a new study by an international team of researchers published in the Journal of Vertebrate Paleontology.

The new species is a long-necked, plant-eating dinosaur known from a single trunk vertebra that is about a half meter tall and wide. The vertebra bears a distinct pattern of bony struts that identify it as the new dinosaur species Perijasaurus lapaz (pear-EE-hah-SOW-roos la-PAHZ)—named in recognition of the mountainous region where it was found and for the 2016 peace treaty that allowed scientists to pursue their research decades after the fossil remains were found in 1943.

Perijasaurus is the northernmost occurrence of a sauropod in South America and represents an early phase in their evolutionary history.

Aldo Rincón Burbano, a professor of physics and geosciences at the Universidad del Norte in Colombia, collects samples in the Serranía del Perijá in Colombia. Image credit: Jeff Wilson Mantilla, University of Michigan
Aldo Rincón Burbano, a professor of physics and geosciences at the Universidad del Norte in Colombia, collects samples in the Serranía del Perijá in Colombia. Image credit: Jeff Wilson Mantilla, University of Michigan

“This new genus and species in the paleotropics allows us to understand a little more about the origin of the sauropods in the Jurassic, as well as how they set the stage for later sauropods from the Cretaceous,” said study lead author Aldo Rincón Burbano, professor of physics and geosciences at the Universidad del Norte in Colombia.

The fossil was first discovered in 1943 during a geological mapping campaign by the Tropical Oil Company. The specimen was taken to the collections of University of California, Berkeley and preliminarily described in 1955.

University of Michigan paleontology curator and professor Jeff Wilson Mantilla examined the specimen as a graduate student in 1997 and later developed a project supported by the Fulbright Foundation to study early sauropod evolution in Colombia.

As part of that project, the Colombian specimen was loaned to U-M, where chief preparator William Sanders removed glues and plaster, greatly increasing the visibility of anatomical details and reducing the total weight of the sample.

“Following repreparation of the fossil, we were able to better visualize the delicate bony laminae that interconnect the projecting parts of the vertebra—the spine, the intervertebral articulations, the rib articulations—the architecture of those connections provides critical morphological information that identifies it as a new species and places it within the sauropod family tree,” Wilson Mantilla said.

A single trunk vertebra that is about a half meter tall and wide has allowed scientists to identify a new species of  long-necked, plant-eating dinosaur. Image credit: U-M Online Repository of Fossils viewer developed by the U-M Museum of Paleontology
A single trunk vertebra that is about a half meter tall and wide has allowed scientists to identify a new species of long-necked, plant-eating dinosaur. Image credit: U-M Online Repository of Fossils viewer developed by the U-M Museum of Paleontology

A 3D model of the specimen is hosted on the University of Michigan Online Repository of Fossils.

A conflict since 1964 between the Colombian military forces, the FARC guerrilla group and paramilitary groups made it unsafe to conduct research in Serranía del Perijá, near the border between Colombia and Venezuela, until the peace agreements in 2016.

Since then, the research team has been working to determine with higher precision where the fossil was found. A satellite image of the region was superimposed upon a hand-drawn map from 1955 showing the location of the fossil. A further clue was provided by sediment removed from the vertebra itself during the preparation process—allowing the team to determine the specific layer from which the bone was
collected. Fieldwork at the site and neighboring localities helped to reconstruct the paleoenvironment the dinosaur inhabited.

“Perijasaurus lived in an environment of low slopes associated with a river and a forested area. We found fine sand and leaf debris in the sediment deposited in the area where the vertebra was originally found, and it is consistent with the sediment within the neural arch of the vertebra, which are only preserved near a floodplain, i.e., near the slopes of a river, a wooded area,” said Daniel Raad, a former geology student at the Universidad del Norte.

Most of the discoveries of dinosaurs in South America come from rocks from the Cretaceous period located in Argentina and Brazil. Dinosaurs from the northern part of South America are much rarer, particularly during the Jurassic and Triassic periods, during the initial radiation of dinosaurs, when landmasses were still substantially interconnected.

“Although Perijasaurus is represented by a single vertebra, that region of ​​the skeleton provides the most information in sauropods, due to a series of laminae and other structures,” said Martín Ezcurra, a paleontologist and associate researcher of the CONICET (Argentina’s National Council for Scientific and Technical Research) and head curator of paleovertebrates at the Argentine Museum of Natural Sciences.

The researchers were able to determine the evolutionary relationships of Perijasaurus through a computational analysis focusing on Early and Middle Jurassic sauropods.

“Perijasaurus is part of the early radiation of sauropods, which includes species from southern South America, Africa, Asia and Europe,” said Harold Jiménez Velandia, a geologist at the University of Caldas.

The presence of Perijasaurus in the paleotropics of South America, together with its close phylogenetic relationship with geographically widespread species that inhabited low latitudes, suggests that sauropods diversified and dispersed fairly rapidly following a major anoxic event at the end of the Lower Jurassic, when portions of the oceans were depleted of oxygen over large geographic areas.

“What we see in the Early Jurassic, both in high latitudes and in the most tropical areas, is that sauropod species were evolutionarily and geographically interconnected, which is something that had also been seen with other groups of carnivorous and herbivorous dinosaurs,” Ezcurra said.

Patagosaurus is from Patagonia, and it is one of the sauropods most closely related to Perijasaurus. The image of Patagosaurus is a silhouette reconstruction done by Pol et al. (2020)
Patagosaurus is from Patagonia, and it is one of the sauropods most closely related to Perijasaurus. The image of Patagosaurus is a silhouette reconstruction done by Pol et al. (2020)

Sauropods are the largest animals to have walked on land, some reaching estimated lengths of 49 meters and weights of up to 57 metric tons. Their ability to support their weight and move their bodies efficiently stems from a series of adaptations to reduce weight and increase bony support.

An anatomical hallmark of sauropods is vertebral pneumaticity. Essentially, extensions of the air-sac system of the lungs extend into the vertebral column and actually remove internal bone, effectively lightening the skeleton.

Jeff Wilson Mantilla
Jeff Wilson Mantilla

“By the Late Jurassic, sauropods had evolved highly pneumatic vertebrae riddled with air spaces that removed one-half to three-quarters the bone weight. Perijasaurus represents an evolutionary antecedent in which the pneumatic invasions are much simpler and more limited in extent, removing less than a quarter of bone volume,” Wilson Mantilla said.

He said the team will continue to focus on regions of Colombia that have exposures of Jurassic sediments.

“Colombia is emerging as a country with great potential to contribute to the paleontology of the continent and the world,” Wilson Mantilla said.

Perijasaurus is permanently stored at the University of California Museum of Paleontology in Berkeley, California. The research was funded by the Fulbright Foundation, Universidad del Norte, Sam Welles Fund and CONICET.

Adblock test (Why?)

Source link

Continue Reading


STEVE appears over Canada during 'surprise' solar storm –



In the dark of Sunday night and Monday morning (Aug. 7 and 8), a surprise solar storm slammed into Earth, showering our planet in a rapid stream of charged particles from the sun. The resulting clash of solar and terrestrial particles in Earth‘s atmosphere caused stunning auroras to appear at much lower latitudes than usual — and, in southern Canada, triggered a surprise cameo from the mysterious sky phenomenon known as STEVE.

Alan Dyer, an astronomy writer and photographer based in southern Alberta, Canada, caught the wispy ribbons of green and violet light on camera as they shot through the sky.

“STEVE lasted about 40 minutes, appearing as the … aurora to the north subsided,” Dyer wrote on Twitter (opens in new tab) on Aug. 8. “STEVE was ‘discovered’ here so he likes appearing here more than anywhere else!”

Related: Earliest documented aurora found in ancient Chinese text

As Dyer noted, the strange sky glow called STEVE was first described by citizen scientists and aurora hunters in northern Canada in 2017. STEVE is typically composed of an enormous ribbon of purplish light, which can hang in the sky for an hour or more, accompanied by a “picket fence” of green light that usually disappears within a few minutes. 

The glowing river of light may look like an aurora, but it’s actually a unique phenomenon that was considered “completely unknown” to science upon its discovery. Today, scientists have a slightly better idea of what’s going on. 

STEVE (short for “strong thermal velocity enhancement”) is a long, thin line of hot gas that slices through the sky for hundreds of miles. The hot air inside STEVE can blaze at more than 5,500 degrees Fahrenheit (3,000 degrees Celsius) and move roughly 500 times faster than the air on each side of it, satellite observations have shown.

Whereas the northern lights occur when charged solar particles bash into molecules in Earth’s upper atmosphere, STEVE appears much lower in the sky, in a region called the subauroral zone. That likely means solar particles aren’t directly responsible for STEVE, Live Science previously reported. However, STEVE almost always appears during solar storms like Sunday’s, showing up after the northern lights have already begun to fade.

One hypothesis suggests that STEVE is the result of a sudden burst of thermal and kinetic energy in the subauroral zone, somehow triggered by the clash of charged particles higher in the atmosphere during aurora-inducing solar storms. However, more research is needed to uncover the true secrets of STEVE. In the meantime, we can simply bask in its otherworldly glow and wave back at its twinkling green fingers.

Originally published on Live Science.

Adblock test (Why?)

Source link

Continue Reading