A Short History of Nearly Everything

by

Bill Bryson

A Short History of Nearly Everything: Chapter 18 Summary & Analysis

Summary
Analysis
According to Bryson, water is a remarkable substance—and it’s everywhere. Humans are 65 percent water, cows are 74 percent water, and tomatoes are 95 percent water. Most liquids contract when they cool, and water does too, by about 10 percent—but, extraordinarily, it then starts to expand. Once water is solid, it’s 1/10 as voluminous as it was as liquid. This “beguiling” property makes it float on water instead of sink. Without surface ice, too much heat would leave the oceans, and eventually they’d freeze solid. This means that ice is what effectively keeps the oceans warm and liquid. Water’s chemical formula is H2O, meaning that it has two hydrogen atoms and one oxygen atom in each molecule of water.
Bryson wants the reader to marvel at how wondrous the planet we live on is, as emphasized by the fact that water comprises most living things—in addition to possessing chemical properties that prevent the oceans from freezing over. Water, it seems, is essential to life in many different ways, and it’s astounding that one substance is capable of performing all the tasks it does to facilitate human life.
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Humans would be lost without water: after a few days with no water, our lips vanish and our skin contracts so much that we can’t blink. Yet most water on Earth is poisonous to us because of the salt inside it. Strangely, we sweat and cry salty water, but we can’t ingest it—when we have too much salt in our body, water molecules leave our cells and try to dilute and expel the salt, which makes us dehydrated, triggering brain damage and death. This is why we can’t drink sea water, which comprises 97 percent of Earth’s water. Most of the rest exists as ice sheets (like Antarctica). Only 0.036 percent of Earth’s water exists in lakes and rivers, and 0.001 percent exists as water vapor in the air.
Bryson emphasizes both how essential water is to human survival and how little usable water humans have access to on Earth. It might seem that water is abundant because of Earth’s plentiful oceans, but in fact, only a tiny proportion of that water is consumable because too much salt is toxic to humans. Bryson raises this point to dispel the misconception that humans can afford to be careless with water because there’s so much of it on Earth.
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Scientific interest in the oceans only picks up in the 19th century. In the 1830s, British naturalist Edward Forbes surveys various ocean beds and concludes there’s no life below 2000 feet because there’s no light down there. In 1860, however, scientists are shocked to discover clams encrusted on a transatlantic telegraph cable that’s been hauled up for repairs from the ocean floor, triggering a worldwide ocean survey expedition by 240 scientists in 1872. Most insights about the sea, however, come from amateurs. In the 1930s, for example, deep-sea divers Charles William Beebe and Otis Barton invent a “bathysphere”—a precarious deep underwater chamber that hangs at the end of a long cable. They use soda lime cans to absorb carbon dioxide expelled by their bodies. 
Bryson once again alludes to how recent most scientific discovery is—ocean exploration doesn’t even get going until the late 1800s, meaning that scientists have barely had a century to formulate theories about it, and so we still have much to learn. Once again, when it comes to the more challenging of Earth’s environments, sometimes scientific discovery hinges on the insights of daring amateurs. This fact further underscores the need for science to be accessible to non-specialists in order to drive progress forward.  
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Barton subsequently discovers sea life at depths that were previously assumed to be inhospitable to life. Father-and-son divers Auguste and Jacques Piccard also devise a deep-sea vessel in the 1950s, allowing them to successfully descend seven miles down to the deepest point on Earth: the floor of the Mariana Trench. This feat has never been repeated since. The Piccards are surprised to discover life dwelling at this depth. Shortly afterward, the world’s attention shifts to space exploration, and funding for deep ocean exploration wanes. Bryson says it’s strange that we know more about the surface of the moon than the ocean floor—humans have only examined a “billionth” of the ocean’s dark depths.
Beebe, Barton, and the Piccards’ underwater adventures all show, once again, that scientific speculations about environments that humans haven’t traversed are often wrong, meaning that there is a lot of scientific work to do. Humans have only descended the Mariana Trench once and have only explored an infinitesimal fraction of the deep ocean, which shows how little progress scientists have made in this area. Thus, scientific discovery of the oceans is only at its beginning.  
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Nevertheless, explorers have still yielded some curious insights, leveraging a United States Navy’s deep-ocean exploration device called “Alvin.” In 1977, oceanographers discover 10-foot-long tube worms, giant clams, and bacteria living around deep-sea vents in the Galapagos. Shockingly, this ecosystem survives using “chemosynthesis” instead of photosynthesis, deriving energy from hydrogen sulfides instead of sunlight. This was previously thought to be impossible as hydrogen sulfides are toxic to all other known living creatures. Oceanographers also learn that sea organisms can survive at much colder and hotter temperatures than they thought was possible for any life forms, radically revising biologists’ understanding of the conditions necessary for life. 
As with other realms of discovery, what becomes immediately apparent when deep ocean exploration takes off is that the more humans witness in the world, the more we realize how little we know and how fallible our scientific claims are. This is evidenced by the presence of creatures that can survive by means that were previously thought impossible. The presence of such creatures also shows that life is really a wondrous thing, since it somehow exists in the strangest and harshest environments and in very diverse ways. 
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Quotes
When water evaporates, it leaves salt behind, so it would seem that the oceans should get saltier over time—but they don’t. Geophysicists realize that the ocean’s deep-sea vents act like filters: they strip out salt from water and blow clean water back out, maintaining equilibrium in the oceans. Sadly, Bryson says, most research in the 1950s focused on discovering spots in the ocean to dump radioactive waste. Between 1950 and 1999, The United States alone dumps hundreds of thousands of drums leaking plutonium, uranium, and strontium into the ocean—as do most European nations, Russia, China, Japan, and New Zealand. Scientists still have no idea what long-term effects radioactive pollution will have on the oceans and Earth’s overall ecosystem.
Bryson utilizes the example of ocean pollution to show, once again, that humans are frequently reckless with the environments we live in—this time, our oceans, which we pollute with toxic waste. This recklessness is foolish because we know so little about how our actions could impact our ability to sustain life on Earth. Humans, thus, are a tremendous threat to our own existence because we fail to acknowledge the delicate interrelatedness of everything on Earth, and we frequently disrupt the planet’s equilibrium.
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Humans know shockingly little about marine life. For instance, we still have no idea where blue wales mate or why they sing. Some scientists estimate that there could be over 30 million species of sea life in the oceans, “most still undiscovered.” Sea life clusters around shallow waters, and most ocean space is uninhabited—perhaps even uninhabitable. Coral reefs comprise one percent of the ocean’s space, yet they’re home to 25 percent of the world’s fish species. Bryson wonders why humans tax the oceans by overfishing shallow waters. Some shark species, as well as cod in particular, are teetering on the brink of extinction from overfishing. We still overfish despite this, yet we barely know anything about the long-term effects of our actions on the oceans’ ecosystems.
In addition to polluting oceans with toxic chemicals, humans also tax the oceans with overfishing. Bryson stresses that the oceans are deceptively large, as the vast majority of life exists in shallow fishing waters. In this way, humans aren’t only a threat to our own existence—we also frequently drive other species to extinction without a second thought. This behavior is reckless because such effects could trickle up the food chain and dramatically affect the ability of many other species (including our own) to survive.
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