……and a quotidian norm that my barefoot mother followed, we will "save for tomorrow". Thirst of the soul left her asleep beneath the dough of emptiness. The collected logs chanted a song which the ears can see, the nose can hear and the ears can smell. A meal to quell day's thirst but the nights we learned to hibernate bypassing supper. A half-pint of refection for the day exhilarated us.
"I'm really, surprised with such high bacterial density at these high altitudes". This is clearly a harsh environment –Quoted Ulrich Karlson, an environmental microbiologist at Aarhus University in Denmark.
Our atmosphere is multifariously inhabited with viruses, fungi, and bacteria as bioaerosols. The air that living entities sustain on, contains not just oxygen or other gases but billions of diverse microorganisms, yet to a great extent, we are unenlightened with their intendment. Microbial diversity is far-flung in the upper troposphere at a height of 4-6 miles. Microbes sojourn at this elevation, gormandizing carbon compounds thereby warming the planet. This efficacious warmth is crucial in rendering habitability to earth. Present understanding and research on atmospheric air microbiota is in a primitive stage, yet we can hypothesize some aspects with the available data. Few we already know and these roles are epoch-making.
Interestingly, fungi and bacteria have been identified at different atmospheric strata: At an altitude of about 12 km (troposphere) and about 20-40 km (stratosphere) the stratosphere. Penicillium notatum has been found at an altitude of 77 km, while Mycobacterium luteum at 70 km.
Owing to their microscopic size, they are dispersed to distant areas of the world and at higher altitudes along with the wind currents. Noah Fierer, a microbial ecologist at the University of Colorado at Boulder said that "There's increasing recognition that bioaerosols are not just spores that are floating around". Desert dust storms are notable in transporting bioaerosols to great distances. Major Source of dust to Earth's atmosphere is Sahara desert of North Africa and The Gobi, Taklamakan, and Badain Juran deserts of Asia.
AEROMICROBIOTA GREASING THE WHEELS OF LIQUID SUNSHINE: BIOPRECIPITATION
Monsoon is a seasonal shift in the direction of the prevailing winds of a region. Summer monsoon brings heavy rainfall in India, Sri Lanka, Bangladesh, and Myanmar while winter monsoon brings moist air from the South China Sea and Mongolia to Indonesia and Malaysia.
Some species of bacteria, Achaea, fungi and other atmospheric microbiota catalyze the formation of water droplets and ice crystals and. Clouds comprise of frozen droplets that condense around a nucleus that may be a dust particle or a grain of salt. P. syringae is an elongated gram negative bacterium equipped with polar flagella that drives nucleus condensation and bolsters ice droplets formation. Airborne microbiota might be critical for condensation and hence cloud formation. Our atmosphere upholds the development of specific adaptations for certain microbes, constituting air microbiome.
Cindy Morris, a plant pathologist has studied how bacteria can help sally forth rain by increasing the freezing temperature of water. Apart from desert dust winds for dispersal, bacteria in the soil can hitch into raindrops and thereby get deposited into the air once the drops crackle. The wind conditions may aid in the translocation of these bacteria higher into the sky.
Paleobotanical studies suggest that Asian monsoon system evolved 8 mya. It is critical to note that Asian summer monsoon rainfall has remarkably decreased over the past 100 years, due to air pollution causing droughts in many regions.
AEROMICROBIOTA HOLDING OFF PATHOSIS: HEALTH
Current studies propose that phylogenetic characteristics of indoor microbiota composition precede asthma development. In a study, among 658 genera of microbes found in dust samples the abundance of the Lactococcus genus was found to be a risk factor for asthma. Twelve bacterial genera, chiefly from the order Actinomycetales were identified to be protective. The relative abundance of these 12 genera significantly reduced asthma development.
The bacterial richness and Shannon diversity index was significantly lower in the homes of children who were asthmatic compared to healthy non-asthmatic individuals. When models were adjusted for confounding factors, it revealed that bacterial richness was inversely proportional to the asthmatic environment.
AEROMICROBIOTA: DIVERSITY
Air samples from a height of about 10 km, were collected during NASA's Genesis and Rapid Intensification Processes experiment that examined how hurricanes form and grow.
Researchers from Georgia Tech analyzed the air samples by gene sequencing techniques and confirmed the presence of about 17 different bacterial taxa. They suggested that on an average 20 percent of the small particles in the upper atmosphere are living bacterial cells, a higher proportion than in the near-Earth atmosphere. The air dwelling microorganisms are vast and somehow play a major role in sustaining life on earth.
AERMICROBIOTA AND THE BLACK SKY: POLLUTION
Air pollution is a heterogeneous mixture of gases like carbon dioxide, carbon monoxide, and sulfur dioxide, volatile organic, and particulate matter. Along with the macrobiota, the microbiota is also affected by air pollution. The small size of microorganisms, the variety of metabolic states, and the various microbial habitats have hampered the research on effects of air pollution on aeromicrobiota.
Bacterial aerosols are drastically influenced by air ions. Aerosols of S. marcescens, when were exposed to laboratory-generated air ions showed large decay rates wherein negative ions were found to be more lethargic. Air ions were also found to affect the germination of fungal spores. Artificially provided air ions showed a decrease in the germination of P. notatum and V. crassa spores. In a set of experiments, it was revealed that ten minutes of exposure to one percent sulfur dioxide was lethal to P. citrophthora, while a little higher SO2 concentration was required to kill P. italicum and P. digitatum. Nitrogen dioxide at concentrations of about 0.25 percent was lethal to a variety of bacteria like P. fluorescens, Clostridium species.
It would be lousy to call polluted air mediated lethality of aeromicrobiota to be beneficial in decreasing aerial transmission of animal and plant pathogens, as on the contrary we now know how atmospheric air microbiota plays an important role in health, precipitation and other aspects. R. meliloti is an air dwelling microbe that has an important role in nitrogen fixation.
Most importantly airborne microbes were thought to be dormant or physiologically inactive but recent studies showed that microbes situated in clouds, especially cumuliform clouds, were actively metabolizing. Need not to mention that polluted air depreciates aeromicrobial metabolic functionality and hence survivability.
FALSTAFF: THE ANALOGY
Falstaff is a well-known character in the plays of William Shakespeare, showcased as a fat man with a paunch. The human gut is endowed with about 10^14 microorganisms of approximately 1000 different species weighing 2-3 kg in a normal individual! Gut microflora plays an important role in immunity and overall development; most of the species colonize the gut during the infant stage. . Recent studies suggest that the human gut microbiome can be perturbed by environmental aero-microbial exposures.
Falstaff with a fat round paunch is an analogy of mother earth, harboring atmospheric air microbiota that sustains life on earth -the same way as gut microbiome renders immunity to humans.
Remembering my childhood in the first paragraph I perceive, cry of the wounded nature as an emphatical chanting, screeching to each and every individual, “we do need to save for tomorrow”. All can see and hear the poignancy of the chant, the time is to endeavor or else the consequences would soon be inevitable. Defiling atmosphere by cold-blooded humans in illimitable ways would soon emanate subsistence on earth....
Komentáře