In an article that appeared yesterday, “Researchers document astounding number of microbial and fungal species transported with high-altitude dust plumes”, scientists from the University of Washington, headed by David Smith, tested material gathered in 2011, shortly after the Fukushima catastrophe, from a mountaintop in Oregon. A huge amount of fungi and bacteria were found. The results were published in Applied and Environmental Microbiology, and is available here.
Over 7 million tons of dust, pollutants, microorganisms and other aerosols cross the Pacific each year. This link includes graphics and a high-resolution animation from NASA scientists about this process.
“Smith reports that his research enabled him to gather enough biomass in the form of DNA to apply molecular methods to samples from two large dust plumes originating in Asia in the spring of 2011. The scientists detected more than 2,100 unique species compared to only 18 found in the very same plumes using traditional methods of culturing, results they published in July.
“It’s a small world. Global wind circulation can move Earth’s smallest types of life to just about anywhere,” Smith said… “I was very surprised at the concentrations. One might expect the concentrations of cells to decrease with altitude based on fallout and dilution,” Smith said. “But during these plume events, the atmosphere was pooling these cells just as it does with other kinds of air pollution.”…
“I think we’re getting close to calling the atmosphere an ecosystem,” Smith said. “Until recently, most people would refer to it as a conveyor belt, or a transient place where life moves through. But the discovery of so many cells potentially able to adapt to traveling long distances at high altitudes challenges the old classification.”
An ecosystem is a milieu where life grows and thrives, not just moves. The fungi that blew over from Japan in April and May of 2011 were likely contaminated with radionuclides like cesium-137. As shown here in a previous post, melanized fungi (fungus species which contain the pigment melanin) use melanin for an energy source in the presence of radiation. This can keep these species viable over the long trip from Japan. In addition, the aerosols moving into the US from Japan also contained radioactive particles like cesium-137 and iodine-131. There would also have been radioactive gases present in the mix like krypton-85. One could see that these fungi could thrive in this high-altitude environment.
“Kinematic back trajectory modeling suggested air from these events probably originated near China or Japan. Even after traveling for 10 days across the Pacific Ocean in the free troposphere, diverse and viable microbial populations, including presumptive plant pathogens Alternaria infectoria and Chaetomium globosum, were detected in Asian air samples.”
These plant pathogens are melanized fungi, capable of causing cerebral phaeohyphomycosis, and other devastating diseases. The researchers found that when the wind was blowing from Asia, the amount of microorganisms vastly increased, and when the wind did not originate there, this amount vastly decreased.
The mass of fungi found was two orders of magnitude greater than the mass of bacteria, but the authors speculated that the number of cells was roughly equal. “All of the bacterial species recovered in this study (except Pseudomonas frederiksbergensis) are gram-positive, capable of forming endospores and commonly found in soils. Surely cells of all types can be lofted into the atmosphere, but endospore formers may be uniquely capable of surviving atmospheric transport and desiccation on air sampling devices. Endospore formation in Bacillus sp. provides high resistance to ultraviolet radiation or desiccation and the genus is quite common in the aerobiology literature…
“A broad range of fungi were recovered (26 genera), including molds, yeasts, and cup and sac fungi with diverse ecological distributions, mostly from soils and plant debris. Many of the sampled genera release spores in the spring time, explaining the fungal biomass “burst” measured in our study (beginning in April) and others. Some of the 31 species recovered are presumptive allergens or plant pathogens.”
The possibility exists that some of the fungi and bacteria that arrived in the US were mutated. The contaminated fungi are able to make long-distance trips. Some of the particles detected in Oregon came from the stratosphere, so it is likely that they could have spread across the globe.
I think that the spread of radioactive fungi probably happened during the atmospheric bomb-test era, Three Mile Island and Chernobyl, as well as now in the Fukushima era. Yablokov et al documented the high prevalence of Pneumocystis Jirovecii in Chernobyl-contaminated areas. This fungus causes PCP pneumonia in AIDS sufferers and other immunocompromised subjects. Black mold and ringworm fungi were also prevalent. We have already seen black mold become a major issue in areas of the US devastated by Hurricane Sandy.