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face areattracted more powerfully to the like molecules beneath and beside them than to the airmolecules above。 this creates a sort of membrane strong enough to support insects andskipping stones。 it is what gives the sting to a belly flop。
i hardly need point out that we would be lost without it。 deprived of water； the human bodyrapidly falls apart。 within days； the lips vanish 鈥渁s if amputated； the gums blacken； the nosewithers to half its length； and the skin so contracts around the eyes as to prevent blinking。鈥�
water is so vital to us that it is easy to overlook that all but the smallest fraction of the wateron earth is poisonous to us鈥攄eadly poisonous鈥攂ecause of the salts within it。
we need salt to live； but only in very small amounts； and seawater contains way more鈥攁bout seventy times more鈥攕alt than we can safely metabolize。 a typical liter of seawater willcontain only about 2。5 teaspoons of mon salt鈥攖he kind we sprinkle on food鈥攂ut muchlarger amounts of other elements； pounds； and other dissolved solids； which arecollectively known as salts。 the proportions of these salts and minerals in our tissues isuncannily similar to seawater鈥攚e sweat and cry seawater； as margulis and sagan have putit鈥攂ut curiously we cannot tolerate them as an input。 take a lot of salt into your body andyour metabolism very quickly goes into crisis。 from every cell； water molecules rush off likeso many volunteer firemen to try to dilute and carry off the sudden intake of salt。 this leavesthe cells dangerously short of the water they need to carry out their normal functions。 theybee； in a word； dehydrated。 in extreme situations； dehydration will lead to seizures；unconsciousness； and brain damage。 meanwhile； the overworked blood cells carry the salt tothe kidneys； which eventually bee overwhelmed and shut down。 without functioningkidneys you die。 that is why we don鈥檛 drink seawater。
there are 320 million cubic miles of water on earth and that is all we鈥檙e ever going to get。
the system is closed： practically speaking； nothing can be added or subtracted。 the water youdrink has been around doing its job since the earth was young。 by 3。8 billion years ago； theoceans had （at least more or less） achieved their present volumes。
the water realm is known as the hydrosphere and it is overwhelmingly oceanic。 ninety…seven percent of all the water on earth is in the seas； the greater part of it in the pacific； whichcovers half the planet and is bigger than all the landmasses put together。 altogether thepacific holds just over half of all the ocean water （51。6 percent to be precise）； the atlantic has23。6 percent and the indian ocean 21。2 percent； leaving just 3。6 percent to be accounted forby all the other seas。 the average depth of the ocean is 2。4 miles； with the pacific on averageabout a thousand feet deeper than the atlantic and indian oceans。 altogether 60 percent ofthe planet鈥檚 surface is ocean more than a mile deep。 as philip ball notes； we would better callour planet not earth but water。
of the 3 percent of earth鈥檚 water that is fresh； most exists as ice sheets。 only the tiniestamount鈥�0。036 percent鈥攊s found in lakes； rivers； and reservoirs； and an even smaller part鈥攋ust 0。001 percent鈥攅xists in clouds or as vapor。 nearly 90 percent of the planet鈥檚 ice is inantarctica； and most of the rest is in greenland。 go to the south pole and you will bestanding on nearly two miles of ice； at the north pole just fifteen feet of it。 antarctica alone has six million cubic miles of ice鈥攅nough to raise the oceans by a height of two hundred feetif it all melted。 but if all the water in the atmosphere fell as rain； evenly everywhere； theoceans would deepen by only an inch。
sea level； incidentally； is an almost entirely notional concept。 seas are not level at all。
tides； winds； the coriolis force； and other effects alter water levels considerably from oneocean to another and within oceans as well。 the pacific is about a foot and a half higher alongits western edge鈥攁 consequence of the centrifugal force created by the earth鈥檚 spin。 just aswhen you pull on a tub of water the water tends to flow toward the other end； as if reluctant toe with you； so the eastward spin of earth piles water up against the ocean鈥檚 westernmargins。
considering the age…old importance of the seas to us； it is striking how long it took theworld to take a scientific interest in them。 until well into the nineteenth century most of whatwas known about the oceans was based on what washed ashore or came up in fishing nets；and nearly all that was written was based more on anecdote and supposition than on physicalevidence。 in the 1830s； the british naturalist edward forbes surveyed ocean beds throughoutthe atlantic and mediterranean and declared that there was no life at all in the seas below2；000 feet。 it seemed a reasonable assumption。 there was no light at that depth； so no plantlife； and the pressures of water at such depths were known to be extreme。 so it came assomething of a surprise when； in 1860； one of the first transatlantic telegraph cables washauled up for repairs from more than two miles down； and it was found to be thicklyencrusted with corals； clams； and other living detritus。
the first really organized investigation of the seas didn鈥檛 e until 1872； when a jointexpedition between the british museum； the royal society； and the british government setforth from portsmouth on a former warship called hms challenger。 for three and a halfyears they sailed the world； sampling waters； netting fish； and hauling a dredge throughsediments。 it was evidently dreary work。 out of a plement of 240 scientists and crew； onein four jumped ship and eight more died or went mad鈥斺�渄riven to distraction by the mind…numbing routine of years of dredging鈥潯n the words of the historian samantha weinberg。 butthey sailed across almost 70；000 nautical miles of sea； collected over 4；700 new species ofmarine organisms； gathered enough information to create a fifty…volume report （which tooknineteen years to put together）； and gave the world the name of a new scientific discipline：
oceanography。 they also discovered； by means of depth measurements； that there appeared tobe submerged mountains in the mid…atlantic； prompting some excited observers to speculatethat they had found the lost continent of atlantis。
because the institutional world mostly ignored the seas； it fell to devoted鈥攁nd veryoccasional鈥攁mateurs to tell us what was down there。 modern deep…water exploration beginswith charles william beebe and otis barton in 1930。 although they were equal partners； themore colorful beebe has always received far more written attention。 born in 1877 into a well…to…do family in new york city； beebe studied zoology at columbia university； then took ajob as a birdkeeper at the new york zoological society。 tiring of that； he decided to adoptthe life of an adventurer and for the next quarter century traveled extensively through asiaand south america with a succession of attractive female assistants whose jobs wereinventively described as 鈥渉istorian and technicist鈥潯r 鈥渁ssistant in fish problems。鈥潯esupported these endeavors with a succession of popular books with titles like edge of thejungle and jungle days； though he also produced some respectable books on wildlife andornithology。
in the mid…1920s； on a trip to the gal谩pagos islands； he discovered 鈥渢he delights ofdangling；鈥潯s he described deep…sea diving。 soon afterward he teamed up with barton； whocame from an even wealthier family； had also attended columbia； and also longed foradventure。 although beebe nearly always gets the credit； it was in fact barton who designedthe first bathysphere （from the greek word for 鈥渄eep鈥潱nd funded the 12；000 cost of itsconstruction。 it was a tiny and necessarily robust chamber； made of cast iron 1。5 inches thickand with two small portholes containing quartz blocks three inches thick。 it held two men； butonly if they were prepared to bee extremely well acquainted。 even by the standards of theage； the technology was unsophisticated。 the sphere had no maneuverability鈥攊t simply hungon the end of a long cable鈥攁nd only the most primitive breathing system： to neutralize theirown carbon dioxide they set out open cans of soda lime； and to absorb moisture they opened asmall tub of calcium chloride； over which they sometimes waved palm fronds to encouragechemical reactions。
but the nameless little bathysphere did the job it was intended to do。 on the first dive； injune 1930 in the bahamas； barton and beebe set a world record by descending to 600 feet。 by1934； they had pushed the record to 3；028 feet； where it would stay until after the war。 bartonwas confident the device was safe to a depth of 4；500 feet； though the strain on every bolt andrivet was audibly evident with each fathom they descended。 at any depth； it was brave andrisky work。 at 3；000 feet； their little porthole was subjected to nineteen tons of pressure persquare inch。 death at such a depth would have been instantaneous； as beebe never failed toobserve in his many books； articles； and radio broadcasts。 their main concern； however； wasthat the shipboard winch； straining to hold on to a metal ball and two tons of steel cable；would snap and send the two men plunging to the seafloor。 in such an event； nothing couldhave saved them。
the one thing their descents didn鈥檛 produce was a great deal of worthwhile science。
although they encountered many creatures that had not been seen before； the limits ofvisibility and the fact that neither of the intrepid aquanauts was a trained oceanographer meantthey often weren鈥檛 able to describe their findings in the kind of detail that real scientistscraved。 the sphere didn鈥檛 carry an external light； merely a 250…watt bulb they could hold upto the window； but the water below five hundred feet was practically impenetrable anyway；and they were peering into it through three inches of quartz； so anything they hoped to viewwould have to be nearly as interested in them as they were in it。 about all they could report； inconsequence； was that there were a lot of strange things down there。 on one dive in 1934；beebe was startled to spy a giant serpent 鈥渕ore than twenty feet long and very wide。鈥潯tpassed too swiftly to be more than a shadow。 whatever it was； nothing like it has been seenby anyone since。 because of such vagueness their reports were generally ignored byacademics。
after their record…breaking descent of 1934； beebe lost interest in diving and moved on toother adventures； but barton persevered。 to his credit； beebe always told anyone who askedthat barton was the real brains behind the enterprise； but barton seemed unable to step fromthe shadows。 he； too； wrote thrilling accounts of their underwater adventures and even starredin a hollywood movie called titans of the deep； featuring a bathysphere and many excitingand largely fictionalized encounters with aggressive giant squid and the like。 he evenadvertised camel cigarettes （鈥渢hey don鈥檛 give me jittery nerves鈥潱！n 1948 he increased thedepth record by 50 percent； with a dive to 4；500 feet in the pacific ocean near california； butthe world seemed determined to overlook him。 one newspaper reviewer of titans of the deepactually thought the star of the film was beebe。 nowadays； barton is lucky to get a mention。
at all events； he was about to be prehensively eclipsed by a father…and…son team fromswitzerland； auguste and jacques piccard； who were designing a new type of probe called abathyscaphe （meaning 鈥渄eep boat鈥潱！hristened trieste； after the italian city in which it wasbuilt； the new device maneuvered independently； though it did little more than just go up anddown。 on one of its first dives； in early 1954； it descended to below 13；287 feet； nearly threetimes barton鈥檚 record…breaking dive of six years earlier。 but deep…sea dives required a greatdeal of costly support； and the piccards were gradually going broke。
in 1958； they did a deal with the u。s。 navy； which gave the navy ownership but left themin control。 now flush with funds； the piccards rebuilt the vessel； giving it walls five inchesthick and shrinking the windows to just two inches in diameter鈥攍ittle more than peepholes。