Monday, September 30, 2013

Pea soup

West Lake, Hangzhou, China 2007
Photograph by the author

While we fracture the habitat we can see — that is, the environment that larger organisms live in — the smaller one is turning into pea soup.

What I mean by this is that microbes, which are far more portable and perceive no real overall barriers to movement other than temperature and Ph, are spreading out of their micro-environments into new ones all over the planet at the greatest rate in the history of earth.

 This is because mankind carries and microbes with him wherever he goes, in his body, on his body, and in and on the artifacts, plants, and animals that he moves from place to place. Left to themselves, most of these objects (for example, floating logs) and creatures (land-based animals) don't move very far, or, if they do, carry a community of microbes that is in many ways specifically limited to the habits of their organism and the niches they frequent.  So a sea turtle, an albatross, a migratory herd mammal, do move microbe populations around, but within a describable set of boundaries.  The vast majority of microbes don't travel to completely new and novel environments so rapidly; their sheer size and attunement to the immediate surroundings prevent it.

Mankind has changed that a great deal, because he is extraordinarily mobile, especially in the past several centuries. Diseases have traveled with him; the introduction of smallpox to the Americas led to a holocaust which is only now being fully appreciated by archaeologists. It's possible that as much as 9/10 of the native populations, which used to be enormous, died off in a very brief period of time. More recent examples are the outbreaks of unique and objectively terrifying diseases such as AIDS, SARS and Ebola virus, which were originally resident in wild animal populations (monkeys, civet cats, and bats, respectively) but entered the human population due to increasing contact between wild animals and expanding communities of human beings.

These examples of dangerous diseases are just the ones that have come to our attention; and we are generally more preoccupied with diseases that affect us directly. Diseases such as white nose syndrome, which is wiping out bats on the East Coast of the United States, are equally destructive, but the overall tendency of the average person is to ignore what happens to animal populations.

What is completely under-appreciated is that similar outbreaks of disease, invasion, and the crippling and fundamental alteration of species mixes is taking place on a microbial level. Human beings are carrying microbes into every corner of the globe and having dramatic impacts on the microbe mixes in those communities.  When highly active agencies such as human beings arrive on the scene, size, which used to limit the spread of bacterial and microbial populations, is no longer a liability when it comes to dispersal— it is an advantage. Remember this phrase — highly active agencies — we'll get back to it.

There are invasive microbes, just as there are invasive types of grass, birds, snakes, and so on. Because these invasions and "species disasters" are taking place on a microscopic level, we are completely unable to appreciate them—unless they directly affect us, or another large creature.

The difficulty here is that we are unable to evaluate the mixing and fundamental alteration of microbial communities until it is far too late to understand it.

In order to understand why this is vitally important, it's necessary to understand the role that microbe communities play in the existence of larger ecosystems. This, also, has been largely ignored in the biology community until the last decade or two, because microbes and fungi were considered to be small and relatively insignificant. The study of them is esoteric and limited to a tiny cadre of experts; intensive study of microbes for over a century meant the study of infectious diseases, and almost nothing else. One might argue that it was only the advent of the understanding of extremophiles that led mankind to understand there were extraordinary things outside of the questions raised by the medical field going on in the microbe community.

 In the next post, we'll engage in a brief discussion about the role of microbes and the larger communities they live in. In the meantime, keep in mind that we are creating a kind of pea soup around us, in which bacteria mix in completely novel ways, fundamentally altering the way that our ecosystems function.

These alterations are microscopic, and will take many centuries to play themselves out, but they are poised to have a profound and fundamental long-term impact on the mix of macroscopic species that we share our environment with.

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