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Blue whale singing patterns reverse when they start to migrate



Oct. 1 (UPI) — For the last five years, an underwater microphone deployed by the Monterey Bay Aquarium Research Institute, positioned on the Monterey Bay seafloor, several hundred feet beneath the surface of the ocean, has been recording the sounds of sea — including the spooky songs of blue whales.

While analyzing the tremendous wealth of data, researchers noticed blue whale songs follow a seasonal pattern, according to a study published Thursday in the journal Current Biology.

Recordings from the summer months, when the blue whales were visiting the Pacific and spending their days eating krill, revealed a preference for nighttime singing. But the audio recorded during the fall and winter demonstrated a reversal — silent nights and days filled with song.

“This was a very striking signal to observe in such an enormous dataset, and led us to ask the questions: what drives these population-level patterns in song, and do these patterns indicate changes in blue whale behavior through the seasonal cycle?” lead researcher William Oestreich, a doctoral candidate in biology at Stanford University, told UPI in an email.

To answer those questions, Oestreich and his colleagues turned to tags, which helped the research team track the diving, movement, feeding and singing behaviors of individual whales.

“We found that individual blue whales that are feeding and have not yet started migrating south sing primarily during the night, whereas blue whales which are migrating sing primarily during the day,” said Oestreich, lead author of new paper.

“By analyzing data from these tags, we discovered that the nighttime tendency for singing that these whales display during their months of feeding is driven by a tradeoff between singing and feeding behaviors within a 24-hour day,” he said.

During the day, krill are often found densely packed deep beneath the ocean surface. To take advantage of this concentration of food, blue whales spend most of the daylight hours during the summer diving and eating. At night, the krill rise to the surface and spread out, and as a result, whales have more time to sing.

“Once these whales begin migrating south, however, they feed very sparsely — and often not at all,” Oestreich said. “Because there is no longer a tradeoff between this deep water feeding behavior and singing, the individual whales are able to sing throughout the daytime during migration.”

Scientists aren’t sure why migrating blue whales tend to stop singing at nighttime.

The acoustic signature discovered by Oestreich and his research partners will help marine biologists and conservation scientists track blue whale migrations.

Blue whales, the largest mammals on Earth, rely on the large krill populations found off the west coast of North America to fuel their trek south to their breeding grounds off the Pacific coast of Central America. According to Oestreich, understanding their season movements is key to protecting blue whale populations.

“We are now better able to monitor when these blue whales are migrating in relation to changes in the ecosystem they inhabit,” Oestreich said.

The newly analyzed acoustic recordings have also offered researchers new insights into why blue whales sing. The data showed the whales tend to sing more and more as they prepare to migrate, which lends support to theories that singing is mostly the domain of male whales and used to attract mates.

It’s possible blue whale songs serve multiple purposes, and researchers hope to continue using a combination of tracking data and hydrophobic recordings to better understand how and why blue whales deploy their vocal tools.

“Now that humans are able to determine whether these blue whales are feeding or migrating just by listening, it begs the question: do blue whales listen and use this signal as well?” Oestreich said.

“These animals live in low population densities over vast stretches of the Pacific Ocean with variable conditions and food supplies, meaning that making a ‘well-informed’ decision about when to give up on feeding and start migrating south is difficult based on one’s immediate surroundings,” he said.

It’s possible the songs of individual whales encode information that help their relatives make better decisions about when to feed and when to begin their trek south to breed, but Oestreich said more research is needed.

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NASA’s OSIRIS-REx touches down on asteroid Bennu to nab sample



Oct. 20 (UPI) — NASA’s OSIRIS-REx touched down on asteroid Bennu on Tuesday evening in a mission to scoop a sample of rocks and dirt.

The spacecraft — the Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer — made soft contact with the asteroid at 6:12 p.m. EDT.

The historic “touch and go” event featured animation displaying OSIRIS-REx’s sample collection activities in real time. It takes time for real images of the touchdown to travel back to the Earth, so they won’t be released to the public until Wednesday.

The craft executed a series of maneuvers over the course of several hours before making soft contact with the surface of the asteroid to collect regolith, or rocks and dirt.

“It will be four and a half hours of anxiousness,” Beth Buck, OSIRIS-REx mission operations manager at Lockheed Martin Space, said in a news conference ahead of the event.

Buck made a comparison to the descent of a spacecraft on Mars, when there is typically “seven minutes of terror.”

The goal is to learn more about the solar system’s history and help “planetary defense” engineers with missions to protect earth from rogue asteroids. Bennu is believed to be a window into the solar system’s past since it’s a pristine, carbon-rich body carrying building blocks of both planets and life.

At around 1:50 p.m. EDT, the spacecraft left orbit around the asteroid before executing a series of burns to position itself over a sampling area nicknamed Nightingale.

Once in position, the craft began its approach to the asteroid at 5:50 p.m. EDT. It then spent about 15 seconds attempting to collect the regolith sample before backing away again.

The area, which is 52 feet in diameter, will make for a more demanding landing than expected, Kenneth Getzandanner, OSIRIS-REx flight dynamics manager at the NASA Goddard Space Flight Center in Maryland, said in the news conference.

The original mission called for a landing “zone” about 150% larger than Nightingale, at 82 feet, but that changed because Bennu was more rocky than expected.

The goal was to collect at least 1.7 ounces of fine-grained material, but the spacecraft can carry up to 4.4 pounds, Heather Enos, OSIRIS-REx deputy principal investigator at the University of Arizona said.

“I would love for that capsule to be completely full,” Enos said.

Though early images from the asteroid should hint at whether the mission succeeded, it will take engineers roughly 10 days to compare and analyze the mass before and after the maneuver to actually know how much dirt is inside the OSIRIS-REx.

If it failed, the spacecraft has enough fuel to attempt two more touch downs to collect material.

The spacecraft is expected to return to Earth, with the regolith sample from Bennu, in 2023.

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SpaceX scrubs Starlink launch until Thursday, if weather cooperates



Oct. 21 (UPI) — Just three days after sending 60 more Starlink satellites into orbit, SpaceX is aiming to launch another batch of broadband satellites into space from Florida.

If the weather cooperates, Thursday’s launch will be SpaceX’s 15th Starlink mission.

Liftoff had been scheduled for 12:29 p.m. EDT Wednesday aboard a Falcon 9 rocket at Launch Complex 40 at Cape Canaveral Air Force Station, but controllers scrubbed the launch due to weather and rescheduled for 12:14 p.m. on Thursday.

With a launch Sunday, SpaceX increased the size of their Starlink constellation to nearly 800 satellites. The 15th mission will see another 60-odd satellites join the network.

“The goal of Starlink is to create a network that will help provide Internet services to those who are not yet connected, and to provide reliable and affordable Internet across the globe,” according to the Kennedy Space Center.

Weather for Wednesday’s planned launch had looked so-so and the Space Force’s 45th Weather Squadron predicted a 60 percent chance of favorable conditions.

“A mid-level inverted trough and associated easterly wave currently across the Bahamas will meander into the state over the next few days, bringing enhanced moisture, cloud cover, and instability with a higher coverage of showers and storms,” Space Force forecasters wrote.

They said Thursday’s forecast looks quite similar to Wednesday’s.

Earlier this month, SpaceX founder and CEO Elon Musk tweeted that Starlink’s constellation was big enough to begin beta-testing the Internet service system in both the United States and southern Canada.

SpaceX has already offered Starlink Internet services to emergency responders in wildfire-stricken areas of Washington State.

Washington’s Hoh tribe is also using the Internet service to provide their members online education and telehealth services.

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Chernobyl-level radiation harms bumblebee reproduction



Oct. 21 (UPI) — Bees are more sensitive to radiation than scientists thought. Scientists found the reproduction rates of bumblebees declined significantly when exposed to Chernobyl-level radiation.

The research, published Wednesday in the journal Proceedings of the Royal Society B: Biological Sciences, suggests radiation in Ukraine’s Chernobyl Exclusion Zone could impair pollination services, triggering wider ecological consequences than previously estimated.

Humans are not allowed to live in the Chernobyl Exclusion Zone, the disaster area more directly impacted by the 1986 nuclear accident, the worst in history. However, the destroyed nuclear reactors are surrounded by forests that are populated by robust populations of birds, bears, bison, lynx, moose, wolves and more.

Efforts to gauge the effects of radiation contamination on insects have yielded mixed results in the past. While some studies have suggested insects are relatively radiation-resistant, others have demonstrated significant impairment.

When researchers exposed bumblebees in the lab to radiation dose of 100 µGyh-1, an amount approximating exposure inside the Chernobyl Exclusion Zone, reproduction rates among the bees dropped between 30 and 45 percent.

Researchers found a direct correlation between the size of the radiation dose and reproduction rate declines. Lower levels of radiation had a smaller effect, while larger doses yielded greater declines.

Scientists were surprised to find they were able to detect reproductive rate declines at very small levels of radiation exposure.

“Our research provides much needed understanding as to the effects of radiation in highly contaminated areas and this is the first research to underpin the international recommendation for the effects of radiation on bees,” lead study author Katherine Raines, environmental scientist at the University of Stirling in Scotland, said in a news release.

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