Buzz
Fluorescence goes far beyond fireflies and glow-in-the-dark toys. It's the process where absorbed light is re-emitted, responsible for some of nature's most mesmerizing displays and groundbreaking scientific revelations.
In recent times, glowing phenomena have appeared in the most unexpected places, among surprising species, and in ways unseen by the naked eye. Even more fascinating, fluorescence is tied to numerous unsolved puzzles, visible from space, and could pose dangers to humans.
10. Bioluminescent Mushrooms
It might be hard to fathom, but glowing mushrooms really do exist, with fluorescent fungi sprouting across Brazil and Vietnam. For years, the reason behind their glowing mystery remained unsolved.
To uncover the cause, researchers gathered some specimens in 2015. In the lab, they isolated the compound responsible for the glow. Known as oxyluciferin, this chemical is also found in fireflies and bioluminescent marine creatures.
For these mushrooms, the glowing compound serves to attract insects. Once the bugs land on them, they collect spores and disperse them to new areas, assisting in the spread of the fungi.
A further question arose about how the fungi produced luciferins. A closer investigation revealed that the mushrooms created their own unique luciferin, which they combined with oxygen and an enzyme, resulting in the fluorescent glow.
The enzyme's properties suggested it might interact with other types of luciferins, producing additional glowing colors. This hints that there's much more to discover about these otherworldly mushrooms.
9. Risks of Blue Light Exposure
During daylight hours, blue light from electronics and energy-efficient bulbs seems to have few downsides. However, recent studies have revealed a troubling link between blue light exposure at night and a decline in human health.
Blue light has its benefits during the day, such as boosting energy and alertness. But when people unwind with their electronic devices at night, the blue glow from screens activates the brain, disrupting the sleep cycle.
Though it might seem minor, research indicates that a disrupted sleep rhythm can lead to prediabetes. Additionally, there are connections to obesity, heart disease, and cancer.
While scientists have not yet conclusively proven that blue light directly causes these health issues, it does reduce melatonin levels. The absence of this hormone, which controls the circadian rhythm, may be a contributing factor linking blue light exposure to cancer, though the research is still in its early stages.
If it's proven that blue wavelengths are harmful to humans, one environmental advancement will need to be reconsidered. Fluorescent bulbs and LED lights, though more energy-efficient, emit more blue light than any other type.
8. The Discovery of Fluorescent Frogs
In 2017, researchers in Argentina brought home an unremarkable frog. The polka-dot tree frog is primarily green with red spots, and up until then, it had been nothing worth celebrating. That changed when the amphibian was readied for tests, some of which involved examining its tissues under UV light.
To everyone's astonishment, the moment UV light hit the frog, it illuminated entirely. The blue-green glow not only made it the first glowing frog, but also the world’s first fluorescent amphibian.
This is a remarkable feat, as bioluminescence in land animals is incredibly uncommon. The frog’s glow is caused by compounds known as hyloins. While the exact benefits of hyloins remain unclear, they may help the polka-dot frogs spot each other at night. The blue-green radiance is visible to the frogs and also makes them more noticeable during dusk and the full moon.
7. Bioluminescent Tides
At times, unusual plants cause coastlines to glow with ghostly streaks of light at night. In 2018, for example, eerie blue lines illuminated Southern California’s coastline in a stunning display.
The organisms behind this phenomenon are dinoflagellates, a type of algae that can move through the water. During the day, their massive numbers turn the water red. When this happens, it’s called a “red tide.”
In the past, some red tide events caused alarm due to their potential to render seafood toxic for human consumption. However, at night, dinoflagellates create a breathtaking, otherworldly glow that now draws tourists to the beach after dark.
On a chemical level, each dinoflagellate contains both a protein and an enzyme. When disturbed—whether by a wave or a passing creature—the two combine, triggering bioluminescence in the algae.
While the precise nature of this reaction remains unclear, it is believed to be a defensive strategy. The glow could either startle zooplankton, the dinoflagellates' main predator, or attract fish that feed on the plankton.
6. Flowers With Blue Halos
Flower genes struggle to produce blue petals, the exact color that plants desire most. The reason? Bees are naturally drawn to blue, and flowers rely on these buzzing insects to complete their pollination process.
In 2017, scientists uncovered a clever adaptation plants used to attract bees. For flowers that couldn’t produce blue petals, they evolved petals with nanostructures that glowed blue when exposed to sunlight.
These glowing halos acted as neon signs for bees. The tiny reflective scales turned out to be a widespread strategy, found in a variety of flowering species that rely on insect pollination, including some trees.
While most flowers emitted a blue glow, some plants also produced an ultraviolet scattering effect, which helped bees better identify blue. The glowing halos proved to be an even stronger attraction than the natural blue hues. During experiments, bumblebees bypassed the actual colors and headed straight for flowers with blue fluorescence.
5. Solving the Mystery of Glowing Coral
Scientists had long known why corals in shallow waters glow—their green light acts as a sunscreen, protecting them from harmful solar radiation. However, the reason deep-sea corals, which are not exposed to sunlight, also emit fluorescent light remained a mystery.
In 2017, the puzzle was solved. Deep-sea corals don’t glow to protect themselves from light, but rather to capture more of it. At such depths, sunlight is scarce. To thrive, the corals must absorb as much light as possible. However, the blue light found at the ocean's bottom is insufficient to provide the energy they need.
Remarkably, these corals use red fluorescence to transform the blue light into orange-red hues. This conversion helps them produce more food through photosynthesis.
While this discovery is thrilling for researchers, it poses challenges for environmentalists. As global warming causes widespread bleaching of shallow-water corals, the hope was that some species might migrate to deeper waters. However, shallow corals that glow green may not be able to adapt to the deeper waters where survival depends on red fluorescence.
4. When Seabirds Glow
In 2018, researchers came across a dead Atlantic puffin and, almost as an afterthought, decided to examine it under UV light. They were curious to see if it would exhibit any fluorescence, given that crested auklets, a closely related species, are known for their fluorescent beaks.
Puffins’ beaks are easily recognizable under regular lighting, adorned with vibrant colors that are likely intended to attract mates. Despite having a glowing cousin, it was still an unexpected surprise when the ridges on the beak—the cere and the lamella—glowed under UV light.
The exact reason for the puffins' fluorescence remains uncertain, but it may be connected to their ability to perceive UV light. Even in daylight, puffins are likely able to see each other's glowing ridges. The mystery deepens as scientists continue to wonder what the glow looks like to them and how they manage to produce this fluorescence in the first place.
Since only one deceased puffin was examined, scientists still need to eliminate the possibility that the fluorescence observed was the result of decomposition.
3. The First Photograph of a Memory
In a recent study into how memories are formed, researchers decided to explore the brain cells of a slug. The neurons of the marine-dwelling Aplysia californica were chosen because they bear a striking resemblance to human brain cells.
For many years, neuroscientists believed that proteins formed at brain synapses when long-term memories were created. However, it wasn’t until the sea slug's brain was studied that this theory was finally validated.
In a recent experiment, scientists first introduced the feel-good hormone serotonin, which is known to aid memory formation, into the cells. Afterward, they applied a fluorescent protein that was initially green but could turn red when exposed to UV light.
The experiment was straightforward yet highly successful. When subjected to ultraviolet light, the proteins turned red, and their positions were marked. Researchers then stimulated the neurons to form memories. Remarkably, as this occurred, new green proteins appeared between the brain cells, providing the first-ever image of a memory being formed.
In addition to confirming the theory, the study revealed that short-term memories do not involve the creation of new proteins. However, the specific role that the presence (or absence) of these proteins plays in distinguishing short-term from long-term memories remains unclear.
2. Photosynthesis from Space
In 2017, researchers from Australia and NASA introduced an innovative method for tracking climate change. They captured stunning images from space that revealed plant fluorescence. This cutting-edge technique detects solar-induced chlorophyll fluorescence, which is emitted during the photosynthesis process in leaves.
For photosynthesis, plants absorb carbon dioxide to create sugars. Understanding this process on a global scale is vital for monitoring the planet's climate and the dynamics of its carbon cycle.
To test their theory, scientists employed satellite imagery to capture glowing chlorophyll. They measured the fluorescence levels and compared them with ground-based observations of photosynthesis. The results confirmed that space-based snapshots provided precise data across various vegetation types, regions, and time periods.
This groundbreaking technology doesn't just track plant growth and climate change. The fluorescent imagery could also offer deeper insights into Earth's ecosystem, carbon flow, land management, and biodiversity conservation.
1. Mitochondria’s Strange Heat
In recent years, researchers have developed temperature-sensitive dyes known as 'fluorescent thermometers.' These dyes attach to specific targets within cells, making them ideal for experiments aimed at measuring the heat of mitochondria. These tiny organelles inside cells are responsible for converting oxygen and nutrients into energy, a process that also produces heat.
In 2017, scientists employed a yellow fluorescent dye that dims as temperature rises. When injected into cells, the dye provides a method for measuring temperature. Prior to these tests, it was assumed that mitochondria operated at the body’s normal temperature of 37 degrees Celsius (98.6 °F). However, the experiments revealed that mitochondria run at a much higher temperature—50 degrees Celsius (122 °F).
If a human were to experience such a high body temperature, it would be a life-threatening fever. Fortunately, no known body temperature comes close to matching the extreme heat inside mitochondria. Understanding this unusual heat could challenge many longstanding ideas about how cells function, particularly regarding temperature.
