Antarctic depths called possible 'cradle of life'
May 18,2007 00:00 by Bend_Weekly_News_Sources

Sci­en­tists have found hun­dreds of new sea crea­tures in a vast, dark deep sur­round­ing Ant­arc­ti­ca. Car­niv­o­rous sponges, free-swim­ming worms, crus­taceans, and mollusks liv­ing in the Wed­dell Sea pro­vide new in­sights in­to the ev­o­lu­tion of ocean life, sci­en­tists say.

Re­port­ing in the May 17 is­sue of the re­search jour­nal Na­ture, in­ves­ti­ga­tors de­s­cribed how crea­tures at the bot­tom of the South­ern Ocean—source of much of the world’s deep ocean wa­ters—are like­ly re­lat­ed to an­i­mals liv­ing in both the ad­ja­cent shal­lower wa­ters and in oth­er parts of the deep ocean. 

A type of sea ur­chin known as Cteno­ci­da­ris, whose spines can ex­tend more than 3 inches (7.5 cm). (Cour­te­sy Ar­min Rose/Ger­man Cen­ter for Ma­rine Bio­di­ver­sity)

A key ques­tion is wheth­er shal­low wa­ter spe­cies colonized the deep ocean or vi­ce versa. The re­search find­ings sug­gest the gla­cial cy­cle of ad­vance and re­treat of ice led to an in­ter­min­gling of spe­cies that orig­i­nat­ed in shal­low and deep wa­ter habi­tats, re­search­ers said.

“The Ant­arc­tic deep sea is po­ten­tial­ly the cra­dle of life of the glob­al ma­rine spe­cies,” said lead au­thor An­ge­lika Brandt of the Zo­o­log­i­cal In­sti­tute and Zo­o­log­i­cal Mu­se­um of the Un­iver­sity of Ham­burg. “Our re­search re­sults chal­lenge sug­gestions that the deep sea diver­sity in the South­ern Ocean is poor. We now have a bet­ter un­der­stand­ing in the ev­o­lu­tion of the ma­rine spe­cies and how they can adapt to changes in cli­mate and en­vi­ron­ments.” 

Ka­trin Linse of the Brit­ish Ant­arc­tic Sur­vey added: “What was once thought to be a fea­ture­less abyss is in fact a dy­nam­ic, var­i­a­ble and bi­o­log­ic­ally rich en­vi­ron­ment. Find­ing this ex­tra­or­di­nary treas­ure trove of ma­rine life is our first step to un­der­stand­ing the com­plex re­la­tion­ships be­tween deep ocean and the dis­tri­bu­tion of ma­rine life.”

Three re­search ex­pe­di­tions on a Ger­man re­search ship, as part of a proj­ect called Ant­arc­tic Ben­thic Deep-sea Biodiver­sity, took place be­tween 2002 and 2005. An in­ter­na­tion­al team from 14 organizations stud­ied the sea floor, its con­ti­nen­tal slope rise and chang­ing wa­ter depths to build a pic­ture of the lit­tle known re­gion. They iden­ti­fied over 700 new spe­cies.

Courtesy British Antarctic Survey and World Science