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repeating the exercise today； it has been estimated； would cost at least 100 million。
when underwater researchers realized that the navy had no intention of pursuing apromised exploration program； there was a pained outcry。 partly to placate its critics； thenavy provided funding for a more advanced submersible； to be operated by the woods holeoceanographic institution of massachusetts。 called alvin； in somewhat contracted honor ofthe oceanographer allyn c。 vine； it would be a fully maneuverable minisubmarine； though itwouldn’t go anywhere near as deep as the trieste。 there was just one problem： the designerscouldn’t find anyone willing to build it。 according to william j。 broad in the universebelow： “no big pany like general dynamics； which made submarines for the navy；wanted to take on a project disparaged by both the bureau of ships and admiral rickover； thegods of naval patronage。” eventually； not to say improbably； alvin was constructed bygeneral mills； the food pany； at a factory where it made the machines to producebreakfast cereals。
as for what else was down there； people really had very little idea。 well into the 1950s； thebest maps available to oceanographers were overwhelmingly based on a little detail fromscattered surveys going back to 1929 grafted onto； essentially an ocean of guesswork。 the navy had excellent charts with which to guide submarines through canyons and aroundguyots； but it didn’t wish such information to fall into soviet hands； so it kept its knowledgeclassified。 academics therefore had to make do with sketchy and antiquated surveys or relyon hopeful surmise。 even today our knowledge of the ocean floors remains remarkably lowresolution。 if you look at the moon with a standard backyard telescope you will seesubstantial craters—fracastorious； blancanus； zach； planck； and many others familiar to anylunar scientist—that would be unknown if they were on our own ocean floors。 we have bettermaps of mars than we do of our own seabeds。
at the surface level； investigative techniques have also been a trifle ad hoc。 in 1994； thirty…four thousand ice hockey gloves were swept overboard from a korean cargo ship during astorm in the pacific。 the gloves washed up all over； from vancouver to vietnam； helpingoceanographers to trace currents more accurately than they ever had before。
today alvin is nearly forty years old； but it still remains america’s premier research vessel。
there are still no submersibles that can go anywhere near the depth of the mariana trenchand only five； including alvin； that can reach the depths of the “abyssal plain”—the deepocean floor—that covers more than half the planet’s surface。 a typical submersible costsabout 25；000 a day to operate； so they are hardly dropped into the water on a whim； still lessput to sea in the hope that they will randomly stumble on something of interest。 it’s rather asif our firsthand experience of the surface world were based on the work of five guys exploringon garden tractors after dark。 according to robert kunzig； humans may have scrutinized“perhaps a millionth or a billionth of the sea’s darkness。 maybe less。 maybe much less。”
but oceanographers are nothing if not industrious； and they have made several importantdiscoveries with their limited resources—including； in 1977； one of the most important andstartling biological discoveries of the twentieth century。 in that year alvin found teemingcolonies of large organisms living on and around deep…sea vents off the galápagos islands—tube worms over ten feet long； clams a foot wide； shrimps and mussels in profusion；wriggling spaghetti worms。 they all owed their existence to vast colonies of bacteria thatwere deriving their energy and sustenance from hydrogen sulfides—pounds profoundlytoxic to surface creatures—that were pouring steadily from the vents。 it was a worldindependent of sunlight； oxygen； or anything else normally associated with life。 this was aliving system based not on photosynthesis but on chemosynthesis； an arrangement thatbiologists would have dismissed as preposterous had anyone been imaginative enough tosuggest it。
huge amounts of heat and energy flow from these vents。 two dozen of them together willproduce as much energy as a large power station； and the range of temperatures around themis enormous。 the temperature at the point of outflow can be as much as 760 degreesfahrenheit； while a few feet away the water may be only two or three degrees above freezing。
a type of worm called an alvinellid was found living right on the margins； with the watertemperature 140 degrees warmer at its head than at its tail。 before this it had been thought thatno plex organisms could survive in water warmer than about 130 degrees； and here wasone that was surviving warmer temperatures than that and extreme cold to boot。 thediscovery transformed our understanding of the requirements for life。
it also answered one of the great puzzles of oceanography—something that many of usdidn’t realize was a puzzle—namely； why the oceans don’t grow saltier with time。 at the riskof stating the obvious； there is a lot of salt in the sea—enough to bury every bit of land on theplanet to a depth of about five hundred feet。 millions of gallons of fresh water evaporate from the ocean daily； leaving all their salts behind； so logically the seas ought to grow more saltywith the passing years； but they don’t。 something takes an amount of salt out of the waterequivalent to the amount being put in。 for the longest time； no one could figure out whatcould be responsible for this。
alvin’s discovery of the deep…sea vents provided the answer。 geophysicists realized that thevents were acting much like the filters in a fish tank。 as water is taken down into the crust；salts are stripped from it； and eventually clean water is blown out again through the chimneystacks。 the process is not swift—it can take up to ten million years to clean an ocean—but itis marvelously efficient as long as you are not in a hurry。
perhaps nothing speaks more clearly of our psychological remoteness from the oceandepths than that the main expressed goal for oceanographers during international geophysicalyear of 1957–58 was to study “the use of ocean depths for the dumping of radioactivewastes。” this wasn’t a secret assignment； you understand； but a proud public boast。 in fact；though it wasn’t much publicized； by 1957–58 the dumping of radioactive wastes had alreadybeen going on； with a certain appalling vigor； for over a decade。 since 1946； the united stateshad been ferrying fifty…five…gallon drums of radioactive gunk out to the farallon islands；some thirty miles off the california coast near san francisco； where it simply threw themoverboard。
it was all quite extraordinarily sloppy。 most of the drums were exactly the sort you seerusting behind gas stations or standing outside factories； with no protective linings of anytype。 when they failed to sink； which was usually； navy gunners riddled them with bullets tolet water in （and； of course； plutonium； uranium； and strontium out）。 before it was halted inthe 1990s； the united states had dumped many hundreds of thousands of drums into aboutfifty ocean sites—almost fifty thousand of them in the farallons alone。 but the u。s。 was by nomeans alone。 among the other enthusiastic dumpers were russia； china； japan； new zealand；and nearly all the nations of europe。
and what effect might all this have had on life beneath the seas？ well； little； we hope； butwe actually have no idea。 we are astoundingly； sumptuously； radiantly ignorant of lifebeneath the seas。 even the most substantial ocean creatures are often remarkably little knownto us—including the most mighty of them all； the great blue whale； a creature of suchleviathan proportions that （to quote david attenborough） its “tongue weighs as much as anelephant； its heart is the size of a car and some of its blood vessels are so wide that you couldswim down them。” it is the most gargantuan beast that earth has yet produced； bigger eventhan the most cumbrous dinosaurs。 yet the lives of blue whales are largely a mystery to us。
much of the time we have no idea where they are—where they go to breed； for instance；