Tag: biology

Forming Vesicles on Titan
Scientists are still debating exactly what shifts nature from chemical and physical reactions to living cells. But vesicles — small membrane-bound pockets of fluid carrying critical molecules — are a commonly cited ingredient. Vesicles help cluster important organic molecules together, increasing their chances of combining in the ways needed for life. Now scientists are suggesting that Titan, Saturn’s moon, could form vesicles of its own.
On Earth, molecules known as amphiphiles feature a hydrophilic (water-loving) end and a hydrophobic (water-fearing) one. When dispersed in water, amphiphiles crowd at the surface, placing their hydrophilic end in the water and their hydrophobic end outward toward the air. On Titan, the Cassini mission revealed organic nitrile molecules that behave similarly with methane rather than water.
Their two-sided structure means that these molecules — like Earth’s amphiphiles — will gather at the surface of Titan’s liquids. When methane rain falls on the Titan’s seas, the impact creates aerosol droplets that slowly settle back to the liquid surface. When that happens, the droplet’s molecular monolayer and the lake’s monolayer meet, enclosing the droplet’s contents in a double-layer of molecules that prevent contact between the droplet and the lake.
Within that newly-formed vesicle, all kinds of molecules can bump shoulders, creating new opportunities for complex chemistry. (Image credit: Titan – ESA/NASA/JPL/University of Arizona, illustration – C. Mayer and C. Nixon; research credit: C. Mayer and C. Nixon; via Gizmodo)
Fediverse Reactions
August 5, 2025
Inside Cuttlefish Suction
Cuttlefish, like many cephalopods, catch prey with their tentacles. Suction cups along the tentacle help them hold on. In this video, researchers share preliminary studies of what goes on inside these suction cups as they’re detached. The low pressures inside the suction cup cause water to vaporize, temporarily. As seen for both the cuttlefish and a bio-inspired suction cup, small bubbles form inside the attached cup, coalesce into larger bubbles, and then get destroyed in the catastrophic leak that occurs once part of the suction cup detaches. (Video and image credit: B. Zhang et al.)
Fediverse Reactions
July 16, 2025
Flying Foxes
A sweltering day in India brought out the local giant fruit bats (also called Indian flying foxes) to keep cool in the river. Normally nocturnal, they made a rare daytime appearance to beat the heat. Wildlife photographer Hardik Shelat was lucky enough to catch these awesome images of the bats in flight. True to their name, the animals have wingspans ranging from 1.2 to 1.5 meters, which should give them some impressive lift, even when gliding down near the water. (Image credit: H. Shelat; via Colossal)
Fediverse Reactions
July 4, 2025
Listening for Pollinators
Can plants recognize the sound of their pollinators? That’s the question behind this recently presented acoustic research. As bees and other pollinators hover, land, and take-off, their bodies buzz in distinctive ways. Researchers recorded these subtle sounds from a Rhodanthidium sticticum bee and played them back to snapdragons, which rely on that insect. They found that the snapdragons responded with an increase in sugar and nectar volume; the plants even altered their gene expression governing sugar transport and nectar production. The researchers suspect that the plants evolved this strategy to attract their most efficient pollinators and thereby increase their own reproductive success. (Image credit: E. Wilcox; research credit: F. Barbero et al.; via PopSci)
Fediverse Reactions
July 2, 2025
Evaporating Off Butterfly Scales
This award-winning macro video shows scattered water droplets evaporating off a butterfly‘s wing. At first glance, it’s hard to see any motion outside of the camera’s sweep, but if you focus on one drop at a time, you’ll see them shrinking. For most of their lifetime, these tiny drops are nearly spherical; that’s due to the hydrophobic, water-shedding nature of the wing. But as the drops get smaller and less spherical, you may notice how the drop distorts the scales it adheres to. Wherever the drop touches, the wing scales are pulled up, and, when the drop is gone, the scales settle back down. This is a subtle but neat demonstration of the water’s adhesive power. (Video and image credit: J. McClellan; via Nikon Small World in Motion)
Water droplets evaporate from the wing of a peacock butterfly.
Fediverse Reactions
June 25, 2025
Penguin Poo Seeds Antarctic Clouds
Forming clouds requires more than just water vapor; every droplet in a cloud forms around a tiny aerosol particle that serves as a seed that vapor can condense onto. Without these aerosols, there are no clouds. In most regions of the world, aerosols are plentiful — produced by vegetation, dust, sea salt, and other sources. But in the Antarctic, aerosol sources are few. But a new study shows that penguins help create aerosols with their feces.
Penguin feces is ammonia-rich, and that ammonia, when combined with sulfur compounds from marine phytoplankton, triggers chemistry that releases new aerosol particles. The researchers measured ammonia carried on the wind from nearby penguin colonies and found that the birds are a large ammonia source, producing 100 to 1000 times the region’s baseline ammonia levels. In combination with another ingredient in penguin guano, the researchers found the penguins boosted aerosol production 10,000-fold. That means penguins can actually influence their environment, helping to create clouds that keep Antarctica cooler. (Image credit: H. Neufeld; research credit: M. Boyer et al.; via Eos)
Fediverse Reactions
June 17, 2025
Artificial Reoxygenation
Phytoplankton blooms have blossomed in coastal waters around the world, driven by phosphorus and nitrogen in agricultural run-off. These large algal blooms deplete oxygen in the water, creating dead zones where fish and other marine life cannot survive. Typically, oxygen makes its way into the ocean at the surface, where breaking waves trap air in bubbles that, when tiny enough, dissolve their oxygen into the water. But this process mainly helps surface-level waters, and without means to circulate oxygen-rich water down to the depths, the low-oxygen state persists.
Artificial reoxygenation is a possible countermeasure. Either by bubbling oxygen directly into deeper waters or by pumping surface-level water downward, we could increase oxygen levels in the water column. So far, though, artificial reoxygenation’s success has been limited; tests in a few bays and estuaries show that it’s possible to reoxygenate the water, but the effects only last as long as the artificial mechanism remains active. Stop the pumps and bubblers and the water will revert to its low-oxygen state in just a day. Even so, the measures may be worthwhile on a temporary basis in some places while we adjust agricultural practices and try to mitigate warming. (Image credit: Copernicus Sentinel/ESA; via Eos)
Fediverse Reactions
June 11, 2025
Flamingo Fluid Dynamics, Part 2: The Game’s a Foot
Yesterday we saw how hunting flamingos use their heads and beaks to draw out and trap various prey. Today we take another look at the same study, which shows that flamingos use their footwork, too. If you watch flamingos on a beach, in muddy waters, or in a shallow pool, you’ll see them shifting back and forth as they lift and lower their feet. In humans, we might attribute this to nervous energy, but it turns out it’s another flamingo hunting habit.
As a flamingo raises its foot, it draws its toes together; when it stomps down, its foot spreads outward. This morphing shape, researchers discovered, creates a standing vortex just ahead of its feet — right where it lowers its head to sample whatever hapless creatures it has caught in this swirling vortex. And the vortex, as shown below, is strong enough to trap even active swimmers, making the flamingo a hard hunter to escape. (Image credit: top – L. Yukai, others – V. Ortega-Jimenez et al.; research credit: V. Ortega-Jimenez et al.; submitted by Soh KY)
Fediverse Reactions
June 4, 2025
Flamingo Fluid Dynamics, Part 1: A Head in the Game
Flamingos are unequivocally odd-looking birds with their long skinny legs, sinuous necks, and bent L-shaped beaks. They are filter-feeders, but a new study shows that they are far from passive wanderers looking for easy prey in shallow waters. Instead, flamingos are active hunters, using fluid dynamics to draw out and trap the quick-moving invertebrates they feed on. In today’s post, I’ll focus on how flamingos use their heads and beaks; next time, we’ll take a look at what they do with their feet.
Feeding flamingos often bob their heads out of the water. This, it turns out, is not indecision, but a strategy. Lifting its flat upper forebeak from near the bottom of a pool creates suction. That suction creates a tornado-like vortex that helps draw food particles and prey from the muddy sediment.
When feeding, flamingos will also open and close their mandibles about 12 times a second in a behavior known as chattering. This movement, as seen in the video above, creates a flow that draws particles — and even active swimmers! — toward its beak at about seven centimeters a second.
Staying near the surface won’t keep prey safe from flamingos, either. In slow-flowing water, the birds will set the upper surface of their forebeak on the water, tip pointed downstream. This seems counterintuitive, until you see flow visualization around the bird’s head, as above. Von Karman vortices stream off the flamingo’s head, which creates a slow-moving recirculation zone right by the tip of the bird’s beak. Brine shrimp eggs get caught in these zones, delivering themselves right to the flamingo’s mouth.
Clearly, the flamingo is a pretty sophisticated hunter! It’s actively drawing out and trapping prey with clever fluid dynamics. Tomorrow we’ll take a look at some of its other tricks. (Image credit: top – G. Cessati, others – V. Ortega-Jimenez et al.; research credit: V. Ortega-Jimenez et al.; submitted by Soh KY)
Fediverse Reactions
June 3, 2025
How Insects Fly in the Rain
Getting caught in the rain is annoying for us but has the potential to be deadly for smaller creatures like insects. So how do they survive a deluge? First, they don’t resist a raindrop, and second, they have the kinds of surfaces water likes to roll or bounce off. The key to this second ability is micro- and nanoscale roughness. Surfaces like butterfly wings, water strider feet, and leaf surfaces contain lots of tiny gaps where air gets caught. Water’s cohesion — its attraction to itself — is large enough that water drops won’t squeeze into these tiny spaces. Instead, like the ball it resembles, a water drop slides or bounces away. (Video and image credit: Be Smart)
Fediverse Reactions
June 2, 2025