That Time When the Mediterranean Sea Dried Up & Disappeared: Animations Show How It Happened

We hear a great deal today about the poten­tial caus­es of ris­ing sea lev­els. At a cer­tain point, nat­ur­al curios­i­ty brings out the oppo­site ques­tion: what caus­es sea lev­els to fall? And for that mat­ter, can a body of water so large sim­ply van­ish entire­ly? Such a thing did hap­pen once, accord­ing to the PBS Eons video above. The sto­ry begins, from our per­spec­tive, with the dis­cov­ery about a decade ago of a giant rab­bit — or rather of the bones of a giant rab­bit, one “up to six times heav­ier than your aver­age cot­ton­tail” that “almost cer­tain­ly could­n’t hop.” This odd, long-gone spec­i­men was dubbed Nurala­gus rex: “the rab­bit king of Minor­ca,” the mod­ern-day island it ruled from about five mil­lion to three mil­lion years ago.

After liv­ing for long peri­ods of time on islands with­out nat­ur­al preda­tors, cer­tain species take on unusu­al pro­por­tions. “But how did the nor­mal-size ances­tor of Nurala­gus make it onto a Mediter­ranean island in the first place?” The answer is that Minor­ca was­n’t always an island. In fact, “mega-deposits” of salt under the floor of the Mediter­ranean sug­gest that, “at one point in his­to­ry, the Mediter­ranean Sea must have evap­o­rat­ed.” As often in our inves­ti­ga­tion of the nat­ur­al world, one strange big ques­tion leads to anoth­er even stranger and big­ger one. Geol­o­gists’ long and com­plex project of address­ing it has led them to posit a for­bid­ding-sound­ing event called the Messin­ian Salin­i­ty Cri­sis, or MSC.

MSC-explain­ing the­o­ries include a “glob­al cool­ing event” six mil­lion years ago whose cre­ation of glac­i­ers would have reduced the flow of water into the Mediter­ranean, and “tec­ton­ic events” that could have blocked off what we now know as the Strait of Gibral­tar. But the cause now best sup­port­ed by evi­dence involves a com­bi­na­tion of shifts in the Earth­’s crust and changes in its cli­mate — six­teen full cycles of them. “Dur­ing peri­ods of decreas­ing sea lev­el, the posi­tion and angle of the Earth changed with respect to the Sun, so there were peri­ods of low­er solar ener­gy, and oth­ers of high­er solar ener­gy, which increased evap­o­ra­tion rates in the Mediter­ranean. At the same time, an active­ly fold­ing and uplift­ing tec­ton­ic belt caused water input to decrease.”

The MSC seems to have last­ed for over 600,000 years. At its dri­est point, 5.6 mil­lion years ago, “exter­nal water sources were com­plete­ly cut off, and most of the water left behind in the Mediter­ranean basin was evap­o­rat­ing.” For sea crea­tures, the Mediter­ranean became unin­hab­it­able, but those that lived on dry land had a bit of a field day. These rel­a­tive­ly dry con­di­tions “allowed hip­pos, ele­phants, and oth­er megafau­na from Africa to walk and swim across the Mediter­ranean,” con­sti­tut­ing a great migra­tion that would have includ­ed the ances­tor of Nurala­gus rex. But when the sea lat­er filled back up — pos­si­bly due to a flood, as ani­mat­ed above — the rab­bit king of Minor­ca learned that, even on a geo­log­i­cal timescale, you can’t go home again.

Relat­ed con­tent:

Glob­al Warm­ing: A Free Course from UChica­go Explains Cli­mate Change

A Map Shows What Hap­pens When Our World Gets Four Degrees Warmer: The Col­orado Riv­er Dries Up, Antarc­ti­ca Urban­izes, Poly­ne­sia Van­ish­es

Why Civ­i­liza­tion Col­lapsed in 1177 BC: Watch Clas­si­cist Eric Cline’s Lec­ture That Has Already Gar­nered 5.5 Mil­lion Views

How Humans Domes­ti­cat­ed Cats (Twice)

Based in Seoul, Col­in Mar­shall writes and broad­casts on cities, lan­guage, and cul­ture. His projects include the Sub­stack newslet­ter Books on Cities, the book The State­less City: a Walk through 21st-Cen­tu­ry Los Ange­les and the video series The City in Cin­e­ma. Fol­low him on Twit­ter at @colinmarshall or on Face­book.