Science Round-up: Sunset for the sunflower star, science students under stress, and scary sonar


PNAS: Mites that invest bee hives don’t do what we’ve always thought.
Samuel D. Ramsey, et. al.

Varroa destructor causes considerable damage to honey bees and subsequently the field of apiculture through just one process: feeding. For five decades, we have believed that these mites consume hemolymph like a tick consumes blood, and that Varroa cause harm primarily by vectoring viruses. Our work shows that they cause damage more directly. Varroa externally digest and consume fat body tissue rather than blood. These findings explain the failure of some previous attempts at developing effectively targeted treatment strategies for Varroa control. Furthermore, it provides some explanation for the diverse array of debilitating pathologies associated with Varroa that were unexplained by hemolymph removal alone. Our work provides a path forward for the development of novel treatment strategies for Varroa.

Anything with the species name of “destructor” is a critter which scientists don’t particularly believe to be helpful. But for all the time bee keepers have been at war with varroa mites, we’ve misunderstood just why an infestation of these tiny things was a signal of doom. Or at least, time to bring out the mite-o-cide and cross your fingers. They’re not disease vectors. They’re fat vampires.

Science: Once common, the Sunflower Starfish has been “wiped out” around the world.
C. Harvell, et. al.

Since 2013, a sea star wasting disease has affected >20 sea star species from Mexico to Alaska. The common, predatory sunflower star (Pycnopodia helianthoides), shown to be highly susceptible to sea star wasting disease, has been extirpated across most of its range. Diver surveys conducted in shallow nearshore waters from California to Alaska and deep offshore (55 to 1280 m) trawl surveys from California to Washington reveal 80 to 100% declines across a ~3000-km range. Furthermore, timing of peak declines in nearshore waters coincided with anomalously warm sea surface temperatures. The rapid, widespread decline of this pivotal subtidal predator threatens its persistence and may have large ecosystem-level consequences.

To say that sunflower starfish are predatory is underselling it. They’re voracious. Also, they’re surprisingly speedy. The many-armed starfish eat clams, and snails, and other shellfish, but they’re particularly good at going after sea urchins. The sudden, and near complete collapse of this species is likely to be matched by explosive growth among some of the prey species, and perhaps equal growth of “urchin barrens,” sites where sea urchins have cleared everything in their paths. That, in turn, could affect a whole sequence of other species, including sea otters. 

NBC News: Sonar can scare whales to death.
Mindy Weisberger

Naval sonar has been linked to mass strandings of otherwise-healthy whales for nearly two decades, but the precise mechanisms of how it affects whales has eluded scientists. Now, researchers have explained key details of how this disruptive signal triggers behavior in some whales that ends in death. …

Whales are adapted for deep-sea diving, and beaked whales are the record-holders for the longest and deepest dives. But the new research explains how sonar in certain frequencies disorients and terrifies some beaked whales so much that the experience overrides an important adaptation for deep diving: a slower heartbeat. Extreme fear accelerates a whale’s heart rate, which can lead to decompression sickness; the intense pain of this condition incapacitates the whales, so they strand on beaches and eventually die, scientists reported in a new study. 

A reminder that the Trump White House has recently lifted regulations around the use of sonar, apparently on the grounds that they were put in by the Obama administration, so they must be bad. There are 23 species of beaked whales, many of them exceedingly rare and poorly understood.


Nature: “Replicator” makes copies of whole objects in an instant.
Davide Castelvecchi

They nicknamed it ‘the replicator’ — in homage to the machines in the Star Trek saga that can materialize virtually any inanimate object.

Researchers have unveiled a 3D printer that creates an entire object at once, rather than building it layer by layer as typical additive-manufacturing devices do — bringing science-fiction a step closer to reality.

My cheap-o 3D printer is at this moment slowly making its way through a rather small part. In this case, an arm to help position the payload on my foam-bucket “spacecraft.” And yes, that is still going to happen. But the technology here seems like the kind of thing that could really take these devices from relatively rare techno doodads to something that’s genuinely common.

In CT machines, an X-ray tube rotates around the patient, taking multiple images of the body’s innards. Then, a computer uses the projections to reconstruct a 3D picture.

The team realized that the process could be reversed: given a computer model of a 3D object, the researchers calculated what it would look like from many different angles, and then fed the resulting 2D images into a ordinary slide projector. The projector cast the images into a cylindrical container filled with an acrylate, a type of synthetic resin.

I encourage you to go to the link on this article and see this thing do swirly magic.

Nature: Improving fusion by mixing in some AI.
Mark Herrmann

The pursuit of thermonuclear fusion, the power source of stars, in the laboratory is an ambitious endeavour. For a useful number of fusions to occur, fusion fuel must be heated to tens of millions of degrees so that it produces an ionized gas called a plasma. If such a plasma could be confined for long enough, the energy released by fusions, known as the yield, would greatly exceed the energy invested in the plasma — a long-elusive goal of fusion researchers. In inertial confinement fusion (ICF) experiments, the fusion plasma is generated when high-power drivers, such as lasers, are used to implode fusion fuel. Writing in Nature, Gopalaswamy et al.1 report the use of experimentally trained statistical models to triple the fusion yield and substantially improve the plasma confinement in ICF experiments.

This is actually one of several articles in the last couple of months that suggest that machine learning, evolutionary algorithms, and other forms of AI may be key to dealing with the complex and semi-chaotic nature of reactors on the edge of fusion.

Another thing that has turned up repeatedly — simple simulations constantly overestimate performance. This suggests that controls trained from collected data rather than predictions is critical to success — and maybe that there are factors in fusion we don’t yet understand.


Nature: Humans, Neaderthals, and Denisovans all settled in one spot in Siberia.
Ewen Callaway

Soviet archaeologists began unravelling the story of Denisova Cave, at the foot of the Altai Mountains, in the early 1980s. Since then, scientists have found the fragmentary remains of nearly a dozen ancient humans at the site. The cave became world famous in 2010, after an analysis of the DNA from a tiny hominin finger bone found that the creature was distinct from both modern humans and Neanderthals. It belonged to a previously unknown hominin group, later named Denisovans.

Additional sequencing of the DNA in bone remains from the cave found that Denisovans were a sister group to Neanderthals, and might once have lived across Asia — where they interbred with the ancestors of some humans now living there.

Modern humans whose ancestors lived outside of Africa carry about 2 percent Neanderthal DNA. Those whose ancestry goes to Asia also carry Denisovan DNA. There are hints that there’s a fourth group out there — a human-relative whose bones and tools we don’t know, but who still left behind a genetic legacy. And it wasn’t just the humans who were mixing with the other groups.

Last year, the site produced another spectacular discovery: DNA analysis of a long bone fragment revealed the first ever known ‘hybrid’ of two ancient-human groups, a woman — nicknamed Denny — whose mother was a Neanderthal and father a Denisovan.


Mother Jones: Fire-driven thunderstorms on the rise.
Ed Struzik

As a warming world causes larger, more frequent, and more intense wildfires, fire-driven thunderstorm events are on the rise in places—including Texas, Portugal, South Africa, and Argentina—where they have never occurred before. Mike Flannigan, director of the Canadian Partnership for Wildland Fire Science at the University of Alberta, says that pyroCbs seem to be on the rise because warmer temperatures are likely producing more intense fires with more vigorous plumes of smoke, black carbon, and water vapor, all of which increase the likelihood of pyroCbs.

Climate creates fires, fires create storms, storms create … wait. Isn’t this speech supposed to include something about God and dinosaurs?

Whatever the reason, these episodes can wreak havoc on fire-suppression strategies. Flannigan says that pyroCbs fires are extremely hot and chaotic, especially when the plume collapses. Winds can reach the speed of a tornado. Embers shoot in all directions—in some cases up to three miles. That means sending firefighters in to fight them on the ground is impossible, according to Flannigan.

PyroCbs? I think another term is needed. Something like a We’reScrewedStorm. With fire on top.


This week’s image comes from the work of Andy Brunning at Compound Interest. Visit his site for a larger, easier to read version.

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