First Observations of Biological Particles in High-Altitude Clouds

A team of atmospheric chemists has moved closer to what’s considered the “holy grail” of climate change science: the first-ever direct detections of biological particles within ice clouds. Ice in Clouds Experiment – Layer Clouds (ICE-L) team mounted a mass spectrometer onto a C-130 aircraft and made a series of high-speed flights through a type of cloud known as a wave cloud. Analysis of the ice crystals revealed that the particles that started their growth were made up almost entirely of either dust or biological material such as bacteria, fungal spores and plant material. While it has long been known that microorganisms become airborne and travel great distances, this study is the first to yield direct data on how they work to influence cloud formation.

The team, led by Kimberly Prather and Kerri Pratt of the University of California at San Diego, Scripps Institution of Oceanography, performed in-situ measurements of cloud ice crystal residues and found that half were mineral dust and about a third were made up of inorganic ions mixed with nitrogen, phosphorus and carbon–the signature elements of biological matter.

The second-by-second speed of the analysis allowed the researchers to make distinctions between water droplets and ice particles. Ice nuclei are rarer than droplet nuclei.

The team demonstrated that both dust and biological material indeed form the nuclei of these ice particles, something that previously could only be simulated in laboratory experiments.

“This has really been kind of a holy grail measurement for us,” said Prather.

“Understanding which particles form ice nuclei, and which have extremely low concentrations and are inherently difficult to measure, means you can begin to understand processes that result in precipitation. Any new piece of information you can get is critical.”

The findings suggest that the biological particles that get swept up in dust storms help to induce the formation of cloud ice, and that their region of origin makes a difference. Evidence is increasingly suggesting that dust transported from Asia could be influencing precipitation in North America, for example.

Researchers hope to use the ICE-L data to design future studies timed to events when such particles may play a bigger role in triggering rain or snowfall.

“If we understand the sources of the particles that nucleate clouds, and their relative abundance, we can determine their impact on climate,” said Pratt, lead author of the paper.

The effects of tiny airborne particles called aerosols on cloud formation have been some of the most difficult aspects of weather and climate for scientists to understand.

In climate change science, which derives many of its projections from computer simulations of climate phenomena, the interactions between aerosols and clouds represent what scientists consider the greatest uncertainty in modeling predictions for the future.

“By sampling clouds in real time from an aircraft, these investigators were able to get information about ice particles in clouds at an unprecedented level of detail,” said Anne-Marie Schmoltner of NSF’s Division of Atmospheric Sciences, which funded the research.

Source: EurekAlert

11 Replies to “First Observations of Biological Particles in High-Altitude Clouds”

  1. I’m curious that the article makes no mention at the altitudes at which this phenomena may operate, which seems to me to be critical in this situation. The EurekAlert link also fails to mention altitude in its’ story. More info is needed here.

  2. @ John Hanford:
    Wave Clouds are a mid to upper tropospheric phenomenon. This should mean: from about 5 km on upwards at middle latitudes, higher in the tropics, lower near the polar regions. I’ve seen the most spectacular photos of the type (lenticular) shown in the picture taken at about 7 km, looking slightly down. There also seems to be another type (cirrocumulus like), which hang out much higher.

    I’d also like to know what altitude the researchers were looking at. Wave Clouds can occur over a huge altitude range, right up to the edge of the stratosphere.

    I’m interested in cloud formation because I occasionally model it “on the job” as visual effects for movies.

  3. Thanks Feenix, for your kind reply to my query. I’ve had a interest in meteorology since high school that lasted through college and still interests me today. Fascinating field !

  4. It’s 2009 and we still can’t answer the question “How high does life go?”.

  5. @TD:
    Indian balloon experiments have found fungi and bacteria at an altitude of almost 40 km.

    Small numbers of humans can be found between 200 km and 400 km high up.

  6. @Feenixx – OK, ignoring folks occasionally on the moon and folks in orbit, how high does life naturally go? There’re sporadic reports over the decades of collection of microbes at high altitudes by balloon and rocket, but how high do they get? Do they make it into space? Was Svante Arrhenius transpermia theory correct? The answers are so important, it boggles the mind that the questions are scarcely even raised. To avoid the censoring of non-mainstream theories by the operators of this site, I suppose I have to stop there.

  7. @TD: the idea of life from Mars, say, seeding Earth (or vice versa) is not the least bit controversial today; rocks can get from one planet to the other quite intact, and many bacteria and archaea are known to be able to survive in extremely harsh conditions (e.g. very high g, intense radiation). The feasibility is all but fully demonstrated, only ‘in the field’ confirmation awaits.

    Journeys across inter-stellar space, however, are a completely different kettle of onions …

  8. @Nereid
    Interplanetary transpermia within one solar system does seem to be a no brainer….so life on mars seems nearly assured, contrary opinions from the space scientists of the 60s and 70s notwithstanding.

    The interstellar version of transpermia – via Arrhenius’ theory or something along those lines – would be the grand slam. A moment that comes once in a civilization…the greatest discovery in the history of science.

    If you know a reason why interstellar transpermia will not work, I’d like to hear it. People use to tell me that UV will kill all the microbes that made it into space – at least until India found some UV-resistant microbes in the stratosphere this year. Heat, cold, dryness – all survivable. So what’s next? Cosmic rays?

  9. @TD: it’s mostly a question of time, as I understand it. While a great many prokaryotes are very tough, they are not indestructible, and an interstellar journey would take tens or hundreds of millions of years (and possibly much longer). Radiation resistant bacteria, AFAIK, are resistant in large part because of their ability to repair damaged DNA; however, that repair must be done while the bacterium is not in suspended animation. While it’s in transit, so to speak, it would be unable to make repairs, and damage due to cosmic rays would be cumulative.

    Further, being deep inside a large rock, or even inside a bubble of water inside a salt crystal, say, might prevent total desiccation – so other certain killers may be avoided, there’s no shielding cosmic rays.

  10. “Interplanetary transpermia within one solar system does seem to be a no brainer….so life on mars seems nearly assured”

    That doesn’t follow, such transported life would not be adapted to the environment. The possibility of repeated attempts would not ameliorate that.

  11. Not wanting to speak for TD, I think he (she?) meant life on Mars at some time in the past, as well as possibly today.

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