Why you should care about aerobiology

Last week's Eos had an interesting article on aerobiology (pdf here).  The authors summarize some of the science behing the dispersal of single celled organisms via the air, then talk about the social implications of air-dispersal (eg. the spread of infectious diseases over large distances) and current advances in monitoring and modeling the process (this last bit is left out below, see the article if you're interested).

[Other recent Eos articles are here and here]

The High Life: Transport of Microbes in the AtmosphereBy David J. Smith, Dale W. Griffin & Daniel A. Jaffe 

Microbes (bacteria, fungi, algae, and viruses) are the most successful types of life on Earth because of their ability to adapt to new environments, reproduce quickly, and disperse globally. Dispersal occurs through a number of vectors, such as migrating ani- mals or the hydrological cycle, but trans- port by wind may be the most common way microbes spread. 

General awareness of airborne microbes predates the science of microbiology. Peo- ple took advantage of wild airborne yeasts to cultivate lighter, more desirable bread as far back as ancient Egypt by simply leaving a mixture of grain and liquids near an open window. In 1862, Louis Pasteur’s quest to dis- prove spontaneous generation resulted in the discovery that microbes were actually single-celled, living creatures, prevalent in the environment and easily killed with heat (pasteurization). His rudimentary experi- ments determined that any nutrient medium left open to the air would eventually teem with microbial life because of free-floating, colonizing cells. The same can happen in a kitchen: Opportunistic fungal and bacterial cells cause food items exposed to the air to eventually spoil. 

Unknowingly, Pasteur founded the field today referred to as aerobiology, the science that studies the diversity, influence, and survival of airborne microorganisms. Sci- entists now have the ability to monitor the movement of atmospheric microorganisms on a global scale. But long-term molecular- based measurements of microbe concen- trations are still missing—such information is needed to improve understanding of microbial ecology, the spread of disease, weather patterns, and atmospheric circulation models.

How important is brain temperature? Ask a large predator fish

This is the kind of thing I can't believe they didn't teach me in elementary school.  I knew the platypus was exceptional among mammals for its beak and eggs, but I never knew that some cold-blooded animals (ectotherms) were actually partially warm-blooded (regional endothermy is the technical name). 

I was doing a literature review of the effects of temperature on brain function and cognition, when I ran across this amazing literature. In a famous 1982 Science article, Francis Carey of WHOI demonstrated that swordfish had evolved a specialized organ that simply sat next to their brain and kept it warm by burning calories quickly.  This was important, he argued, because these fish rapidly dove to depths where the water temperature was 20 degrees (C) colder than their normal environment. Because brain function is important to these hunters, it seemed reasonable that it was worth it for them to evolve specialized organs to keep their brains warm.

Sound too fantastic? Since then, cranial endothermy has also been documented in some varieties of sharks and tuna.  Because these species are so far from one another (in an evolutionary sense) and many of their more closely related relatives didn't have brain heaters, its thought that these different groups evolved similar organs independently from one another. This would suggest that maintaining a relatively more stable brain temperature might have large benefits.  Now, does this apply to humans?...