Excerpt from ‘Think: Why you should question everything’ (Prometheus Books, 2013), by Guy P. Harrison: In addition to land and sky, microbes seem to rule the oceans as well. The next time you are walking the sands of your favorite beach, glance out to sea and think about what is out there. But forget fish, plankton, and dolphins, and the usual cast of characters. Those are mere bit players in this world. Even plankton, for all their importance, have been upstaged. It’s the viruses that run things. They infect everything in the ocean, from the smallest bacterium to the largest whale. It is now clear that the ocean is pretty much one big viral infection. Marine viruses are the most abundant form of “life” on all the Earth. (Viruses are so weird that technically they don’t qualify as life. But they’re close enough.) A typical liter (0.26 gallons) of ocean water contains more than one hundred billion viruses! That’s about the same number of all people who have ever lived throughout the entire existence of humans. A kilogram of mud or sediment from the seafloor can easily contain a million or more different species of viruses. Most viruses are much smaller than even bacteria, so they weigh very little, of course. But they are so prolific that their collective weight adds up quickly. For example, all the viruses in the ocean together would weigh as much as the combined weight of 75 million blue whales. Even more mind-boggling, if all marine viruses were placed end to end, they would stretch out into space farther than the next sixty galaxies! Okay, gaudy numbers and dramatic analogies aside, what’s the big deal about a bunch of creepy little parasites that float around, infecting fish, plankton, and everything else in the ocean? They matter because they seem to be nothing less than the framework of the entire ocean. And as the ocean goes, so goes life on land. Viruses may be invisible to our naked eyes, but they shape and effectively control the living ocean that we can see, as well as the rest of the Earth’s biosphere. It’s a common human fault to imagine that we are somehow above or disconnected from the rest of nature. The reality, however, is that we are far more dependent upon worms, bacteria, and viruses than we are on cars, computers, and credit cards. Given the importance of viruses to the way the world is, shouldn’t people devote some time to understanding a bit about them? But no, for millions of people, ghost hunting, astrological research, and other such pursuits beckon, and there is only so much time in a day. Most viruses pose no direct threat to us, by the way. But that doesn’t mean they aren’t ruining somebody’s day. They have their chosen targets, and that’s just what viruses do. They can’t reproduce without hijacking a cell and turning it into their own personal virus factory, so their mission always is to invade and conquer. Marine viruses kill about half of all marine bacteria every day. Overall, they kill about 20 percent of all ocean life every day. This is amazing, especially when you consider what would happen if all those trillions and trillions of bacteria and other creatures were not being snuffed out by viruses on a daily basis. The food chain we rely on would be very different without viral population control—possibly not so well suited to our needs. For example, scientists have known for many years that the microbial ocean plays a major role in the Earth’s atmospheric makeup—and marine viruses have perhaps the biggest say in all of that. So, if you appreciate having food to eat and air to breathe, be sure to thank a virus. If the virosphere still feels distant and disconnected, consider this: You are a virus, at least that’s what your genetic code says. Like it or not, viral footprints are all over humanity. This might not go over well with people who still can’t bring themselves to invite bright bonobos to the family picnic, but viruses deserve a place at the table too. They have been around for billions of years, and that means they have coexisted closely with plants and animals, including us, so close that we are now part them. Our long and intimate evolutionary dance with viruses can’t be denied. It happened. It’s happening. But don’t worry; this is nothing to be ashamed of. We can take pride in having such prominent and influential kin. As is probably clear by now, I’m so fascinated and excited by this branch of science that it’s difficult for me to shut up about it. As a result of living in the same house with me, for example, my otherwise-normal twelve-year-old daughter knows far more about viruses, bacteria, and mites than most college students. What I don’t understand is why everyone isn’t excited about this stuff. Science continues to pull back the curtain on a breathtaking and important show that’s underway. The more we learn, the more it becomes apparent that this is the microbes’ world and we’re just living in it. For example, “you” are made up of 10 trillion or so human cells but this is nowhere near the complete picture. There are about 100 trillion other living cells and various microscopic critters living on you and inside of you right now as well. Some one billion bacteria live on every square centimeter of your skin’s surface. It’s true; it doesn’t matter how many times per day you shower or use hand sanitizer. You are less “you” than you are “other” life. You are outnumbered in your own skin. Right now, there may be herds of tiny Demodex mites grazing on your face like buffalo on the plains of nineteenth-century North America. Closely related to spiders, these microscopic beasts look like a medieval mace, the stick weapon with spikes on one end. Regardless of how clean you are or what you may be up to at the moment, these creepy critters are busy taking care of their own business. They mate, right there on your face, for example, and guess where they go with the fertilized eggs for safekeeping? Down into your pores—where else? They prefer your eyebrow regions, and it’s believed that these mites feast on the oily secretions of your skin. Eating leads to pooing, of course, so how does that work? I have good news and bad news. The good news is that they never poo on you during their entire lifetime because the Demodex has no anus. The bad news, however, is that when they die, their bodies break apart to release a lifetime of poo on your face. See? Reality is never boring. Here’s a trick question you can irritate your friends with: How many visitors from Earth have been to the Moon? The likely answers you will get are: (1) Thirty or so because the astronauts took some frogs, worms, and bugs for experiments in space [Wrong, Apollo astronauts conducted no animal experiments on the Moon.]; (2) None, because the Moon landings were a hoax [Maybe you should find some new friends.]; (3) Twelve, the number of Apollo astronauts who landed on the Moon [Respectable answer, but also very wrong.]. The right answer, of course, is many, many trillions. Only twelve astronauts may have walked on the Moon, but every one of them was host to a staggering assortment of microbes at the time, so each landing was really more like a mass invasion. Yes, you are a bipedal ecosystem, a kind of rainforest or coral reef with legs. Wherever you go, remember that you carry with you a vast and diverse collection of wildlife. You are a wilderness of known and unknown bacteria, viruses, and arthropods. And I won’t even bother going into detail about the fungal forests that cover large tracts of your body’s surface. Cleary you needn’t ever feel alone—because you’re not. I encourage you to think about these things when someone suggests to you that all the exciting and cool action is happening over on the supernatural/paranormal side of the tracks. No, reality holds its own just fine. –from ‘Think: Why you should question everything’ (Prometheus Books, 2013) amazon/Think-Why-Should-Question-Everything/dp/1616148071/ref=la_B001JP2MJC_1_3?s=books&ie=UTF8&qid=1381417816&sr=1-3
Posted on: Thu, 10 Oct 2013 15:16:47 +0000
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