Common murres look like skinny penguins but fly like F-15 fighter jets.
The North Pacific seabirds can quickly cover hundreds of miles searching for schools of small forage fish. Their powerful wings let them dive more than 150 feet (46 meters) under water to gorge on capelin, sand lance, herring, sardine and juvenile pollock.
So biologists were stunned four winters ago when carcasses of emaciated common murres showed up on beaches in what they say was the largest seabird die-off recorded in the world’s oceans. The die-off eventually killed an estimated 500,000 to 1 million murres from California to Alaska, eliminating 10-20% of the northeast Pacific population of the species. Seabird experts now believe they know why.
Common murres were ambushed by effects of the northeast Pacific marine heatwave dubbed “The Blob,” according to a paper published Wednesday by 23 federal, university and private researchers in the science journal PLOS ONE. The heatwave lasted more than 700 days from 2014 to 2016, increasing water temperature and interrupting patterns in the food web from the smallest creatures to top predators.
Forage fish — the main prey of murres— feed on zooplankton, the floating small animals that feed on plant plankton. Cold water produces the biggest, fattiest varieties of zooplankton. But the marine heatwave reduced the nutritional value of zooplankton, researchers concluded, and the lower-grade food stunted the growth of forage fish.
In turn, warmer water increased the metabolism of large fish such as Pacific cod, walleye pollock and arrowtooth flounder, requiring them to eat more forage fish.
That translated into a double whammy for murres, according to the researchers. The seabirds found that their main food source had a fraction of its usual nutrition. Murres also found themselves out-competed by large fish.
“The food just wasn’t there and everybody wanted it,” said lead author John Piatt, a research biologist for the U.S. Geological Survey who has studied seabird for more than 40 years. “And it just got scarcer and scarcer.”
Common murres have marvelous tools for finding forage fish but have an Achille’s heel: Murres must eat 56% of their body mass every day, the equivalent of 60 to 120 finger-length forage fish. If they don’t, they can starve in three to five days, Piatt said.
Murre die-offs have occurred before but never in such numbers and never across three ecosystems, Piatt said, alluding to the California Current System, the Gulf of Alaska and the Bering Sea. Biologists with help from citizen scientists counted or collected 62,000 carcasses, although Piatt says the figure represents only a fraction of the deaths because murres spend most of their time far from shore.
About two-thirds of the dead birds were adults — and that carried ramifications for reproduction. Thirteen murre colonies in the Gulf of Alaska and the Bering Sea, where thousands of murres gather to reproduce, experienced complete failures for at least one breeding season during or after the die-off.
Seabird experts early on suspected naturally occurring toxins played a role in the deaths. So far, there has been no evidence that anything other than starvation could explain the mass mortality, Piatt said.
Pulling together work done by oceanographers, fishery and avian disease experts and data collected by citizen scientists, Piatt and his collaborators focused on effects of the marine heat wave.
The Blob created water with surface temperatures that were more than 4 degrees (2 degrees Celsius) above normal. The heat wave extended hundreds of miles (kilometers) off shore and hundreds of feet (meters) below the surface.
The reasons for the heatwave are unclear. Global warming has slowly raised ocean temperatures over decades. Yet the marine heatwave also is tied to the recurring Pacific climate patterns including El Nino cycles of warm sea surface temperatures and changing patterns of wind speed, direction and duration that help mix ocean waters.
The murre deaths signaled that something was wrong in the ocean but starvation, die-offs, reproduction failures or population declines were recorded in other species: cod, arrowtooth flounder, rhinoceros auklets, tufted puffins, California sea lions and Guadalupe fur seals. Seventy-nine humpback and fin whales stranded during 2015-16, mostly for “unexplained” reasons and in the Gulf of Alaska. The common thread was their reliance on forage fish.
“It sort of hit me — no wonder things were so screwed up, no wonder this thing hit so hard, because the four-inch species is at the heart of all this for the murres, the rhinos, the tufteds the humpbacks,” Piatt said.
Fisheries professor Selina Heppell, the chair of the Department of Fisheries and Wildlife at Oregon State University, said it’s long been known or suspected that there were big impacts from the marine heatwave.
“What this group has been able to do is actually pull several lines of evidence together into a cohesive story,” said Heppell, who was not part of the study.
However, she said the study underscores the need for additional research on forage fish even though many do not have commercial value. “That’s what you really have to get to do to answer these ecosystem-change kinds of questions.”
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Bright-Red "Blood Snow" Is Falling From the Sky in Antarctica – Futurism
A Facebook post by Ukraine’s Ministry of Education and Science shows a research station on an island just off the coast of Antarctica’s northernmost peninsula covered in “blood snow.”
The gory-looking scene is not the result of a seal hunt gone wrong — it’s an astonishingly red-pigmented, microscopic algae called Chlamydomonas nivalis, which thrives in freezing water as the ice melts during Antarctica’s record-breaking warm summer.
When summer hits the polar regions, the algae bloom, staining the snow and ice around it in blood-resembling red, as Live Science explains. The phenomenon was first noticed by Aristotle thousands of years ago and is often referred to as “watermelon snow” thanks to its subtly sweet scent and color.
What makes the blooming algae red is the same stuff that give carrots and watermelons their reddish tint — carotenoids.
It’s a stunning display of a natural phenomenon — but it also creates a nasty feedback loop that causes the ice to melt faster. The red color causes less sunlight to be reflected off the snow, causing it to melt faster, as the Ukrainian team explains in its post. The accelerated melting then causes more algae to grow, completing the cycle.
It’s not the only surreal display in the world caused by such a feedback loop, as Live Science points out. Blooming algae caused sea foam to swallow up the coast of a Spanish town in January. Similar algae blooms even caused shores around islands in the East China Sea to glow blue.
READ MORE: Spooky ‘blood snow’ invades Antarctic island [Live Science]
More on algae: A New Bioreactor Captures as Much Carbon as an Acre of Trees
Scientists detect biggest explosion since Big Bang – BBC News
Scientists have detected evidence for a colossal explosion in space – five times bigger than anything observed before.
The huge release of energy is thought to have emanated from a supermassive black hole some 390 million light years from Earth.
The eruption is said to have left a giant dent in the Ophiuchus galaxy cluster.
Researchers reported their findings in The Astrophysical Journal.
They had long thought there was something strange about Ophiuchus galaxy cluster, which is a giant aggregation containing thousands of individual galaxies intermingled with hot gas and dark matter. X-ray telescopes had spied a curious curved edge to it.
The speculation was that this might be the wall of a cavity that had been sculpted in its gas by emissions from a central black hole.
Black holes are famous for gorging on infalling matter, but they will also expel prodigious amounts of material and energy in the form of jets.
Scientists at first doubted their explanation however, because the cavity was so big; you could fit 15 of our own Milky Way galaxies in a row into the hole.
And that meant any black hole explosion would have to have been unimaginably prodigious.
But new telescope data from the Murchison Widefield Array (MWA) in Australia and the Giant Metrewave Radio Telescope (GMRT) in India seem to confirm it.
“In some ways, this blast is similar to how the eruption of Mount St Helens (volcano) in 1980 ripped off the top of the mountain,” said Simona Giacintucci of the Naval Research Laboratory in Washington, DC, and lead author of the study.
Astronomers have discovered the biggest explosion seen in the universe – CBC.ca
Astronomers have discovered the biggest explosion seen in the universe, originating from a super-massive black hole.
Scientists reported Thursday that the blast came from a black hole in a cluster of galaxies 390 million light-years away.
The explosion was so large it carved out a crater in the hot gas that could hold 15 Milky Ways, said lead author Simona Giacintucci of the Naval Research Laboratory in Washington.
It’s five times bigger than the previous record holder.
Astronomers used NASA’s Chandra X-Ray Observatory to make the discovery, along with a European space observatory and ground telescopes. They believe the explosion came from the heart of the Ophiuchus cluster of thousands of galaxies: a large galaxy at the centre contains a colossal black hole.
First hint of explosion came 4 years ago
Black holes don’t just draw matter in. They also blast out jets of material and energy.
The first hint of this giant explosion actually came in 2016. Chandra images of the Ophiuchus galaxy cluster revealed an unusual curved edge, but scientists ruled out an eruption given the amount of energy that would have been needed to carve out such a large cavity in the gas.
The two space observatories, along with radio data from telescopes in Australia and India, confirmed that the curvature was, indeed, part of a cavity.
“The radio data fit inside the X-rays like a hand in a glove,” co-author Maxim Markevitch, of NASA’s Goddard Space Flight Center in Maryland, said in a statement. “This is the clincher that tells us an eruption of unprecedented size occurred here.”
The blast is believed to be over by now: There are no signs of jets currently shooting from the black hole.
More observations are needed in other wavelengths to better understand what occurred, according to the team.
The findings appeared in the Astrophysical Journal.
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