Credit: Nigel Buchanan
Their hunch was bolstered by findings of melanised fungi, happily congregating in the cooling pools of functional nuclear reactors, and by studies of dark, 'radiation-seeking' fungi, purposefully growing towards radioactive particles in soil, particularly around Chernobyl.
The team looked to the example of photosynthesis as a model, said Casadevall. If plants can use the green pigment, chlorophyll, to absorb energy from the Sun and produce a usable form of chemical energy, they reasoned, fungi might be able to use their melanin pigment and radiation energy in a similar way. They even devised the snazzy moniker, 'radiosynthesis', for the process.
To test their idea, the group analysed three different types of fungi, including Cladosporium sphaerospermum, the species abundant in and around Chernobyl. Using ionising radiation from the radioactive isotope, caesium-137, they exposed the fungi to radiation doses similar to those inside the damaged reactor, and about 500 times greater than the Earth's normal background level.
Melanin-containing fungi exposed to the radiation – even when nutrient-starved on purpose – grew significantly larger and up to 2.5 times faster than fungi without melanin and those not exposed to radiation.
According to Yeshiva's Ekaterina Dadachova, the nuclear chemist who led the study, "the presence of melanin in the cells gives them a distinct advantage over non-melanised cells, in terms of better growth [with radiation]."
Dadachova's team also had a look at what melanin molecules were actually doing, searching for signs of active involvement in the growth process. They were able to show radiated melanin capable of boosting a type of reaction important in metabolism – called an oxidation-reduction reaction – four times faster when exposed to the influence of caesium-137.
They also saw a change in the pigment's electronic structure. This, Dadachova says, is evidence "that melanin transformed part of the ionising radiation energy into the energy of electrons, which represents the 'chemical' form of energy [that] fungi could potentially use in their metabolism."
Taken together, the researchers think their results do indeed hint that fungi can live off ionising radiation, harnessing its energy through melanin to somehow generate a new form of biologically usable growing power.
If they're right, then this is powerful stuff, said fungal biologist Dee Carter from the University of Sydney. The results will challenge fundamental assumptions we have about the very nature of fungi, she said.
It also raises the possibility that fungi might be using melanin to secretly harvest visible and ultraviolet light for growth, adds Casadevall. If confirmed, this will further complicate our understanding of these sneaky organisms and their role in ecosystems.
Uses for this fungus?
I wonder if this melanin-containing fungi could be cultured. Could it be used in space, feeding off cosmic rays or radiation from the spacecraft reactor? I don't think fungi consume CO2 and emit oxygen, but maybe there are other applications for it. What do you think? Any ideas, people?
Radiation-cleanup, fuel, food?
Let's say these funghi are cultivatable.
What do you do when the fungus grows and grows and grows?
Can they be eaten? Is there still radiation left in them?
As for the radiation to electricity story: What would this accomplish? Instead of steam we'd have solid-state fuel. To burn perhaps?
I don't see (maybe because of ignorance, grant you that) how we can turn radioactivity to electricity without a by-product...
My two cents
My best guess is that this supports the soup concept in which life sprung from. Environment that is thought to be uninhabitable by current life forms on planet, strange fungus discovered, reducing the levels of radiation, leading to the area being able to support more complex life forms. I personally think that anything we can create with the elements on this planet or illnesses that can arise have already been addressed by another species on this planet already. It is kinda new age-y however I think that all the cures and solutions have already been built in nature. I think this solution is actually better than a "distilled" one, one that has been isolated from its original source. I call it the buffer theory: Since an organism by nature "fit" into their ecosystem, and by that I refer that they can be the main source of nutrition for some other organism while consuming a undesired source of nutrition, I hypothesis that specific organisms when consumed actually carry their own buffers to prevent drastic side effects, which we encounter with prescription formulas, but aid in survival of another species. I think with Chernobyl - part of the planet got sick and that tripped a restart button, and a fungus started doing what it does best. I don't think there is anything new just facts to be discovered and then lost again, a never ending cycle.
But then again I just cut hair for a living.
the fungi
Ive been doing some related reading about these mushrooms. They feed of radiation the same way a plant feeds off the sun. They don't consume radiation, they feed off the energy it emits. I think a practical use for these could be a radiation detection system. spread the spores around and area of concern. they should stay dormant until radiation is present. if the mushrooms grow you know if you have a problem.
Radiation -> Electricity?
Our current reactor-based electricity generation is really just a glorified steam engine. We heat water which converts to steam that spins a turbine. What if this melanin process could be used to convert radiation directly into electricity? It may not prove to be as scalable as a megawatt steam turbine, but perhaps for small applications like transportation, housing, or even space travel.
Food
Mmmmm.... melanin-rich fungi.... The glories of beeing an astronaut.
On the brighter side, we now know that if the humans destroy each other in a nuclear war, some life will still be left.
Post holocaust
> On the brighter side, we now know that if the humans destroy each other in a nuclear war, some life will still be left.
Was this ever in question?
Well, look what we did to
Well, look what we did to Mars before moving here.
Melanin in humans
One has to wonder if this is the same role that melanin plays in humans - caucasians get a sun-tan after being in the sun a while - is the melanin in our bodies converting the radiation from the sun into something useable? What would this mean for people of African descent? Are they intrinsically better at using the suns radiation?
This isn't meant in a racist way - I'm just curious if the melanin in our bodies plays the same role as the melanin in fungi.
Melanin in Humans, the "energy" question
a sun-tan is a mere baking of the top layer, if I am not mistaken.
Black does absorb better than white does (why are there no "white holes"?)
Thus the question remains: are our African brothers more energetic than us (I am caucassian)? I think the answer is yes... So I guess melanin has some energy-efficient qualities we have not found yet.