As warm­ing seas men­ace fish, com­mu­ni­ties suf­fer Cor­ro­sive water threat­ens wide range of sea life

Kuwait Times - - HEALTH -

MAR­RAKESH, Morocco:

When nearly all the young oys­ter crop died two years in a row at shell­fish farms in the US Pa­cific North­west, work­ers at first sus­pected a virus. But the real cul­prit was a new worry: a change in the acidity of the sea water feed­ing the oys­ter tanks. As the world’s oceans ab­sorb car­bon diox­ide that is build­ing up in the at­mos­phere, seas have be­come 30 per­cent more acidic than they were be­fore the in­dus­trial era, said Carol Tur­ley, a se­nior sci­en­tist at Bri­tain’s Ply­mouth Marine Lab­o­ra­tory.

The in­creas­ingly cor­ro­sive water threat­ens a wide range of sea life, par­tic­u­larly shell­fish such as oys­ters and scal­lops, mak­ing it hard for them to form and main­tain shells.

Warm­ing of the world’s oceans, as they ab­sorb ris­ing heat as­so­ci­ated with cli­mate change, also is killing coral reefs and driv­ing more fish species to­ward cooler seas and away from the re­gions where they have tra­di­tion­ally lived and been caught, Tur­ley said on the side­lines of the re­cent U.N. cli­mate talks in Mar­rakesh. An­other ef­fect of warm­ing is a re­duc­tion in the amount of oxy­gen in the sea, threat­en­ing fish, said Ulf Riebe­sell, a Ger­man ocean re­searcher who works on acid­i­fi­ca­tion, among other prob­lems.

“The ocean is un­der a ma­jor chal­lenge. It’s not only heat­ing up, it’s also acid­i­fy­ing and los­ing oxy­gen. The three stres­sors come si­mul­ta­ne­ously and they play out world­wide,” he said in Morocco.

That is fu­elling new chal­lenges for both rich and poor com­mu­ni­ties around the world, from small-scale fish­er­men who can no longer bring in a catch, to con­ser­va­tion­ists watch­ing fish move out of hard-won re­serves, and coastal and island states fear­ful their tourist in­dus­tries will col­lapse with their ail­ing reefs.

“It’s hap­pen­ing too fast for or­gan­isms and ecosys­tems to de­velop strate­gies to cope,” said Hans Port­ner, a sci­en­tist with the Ger­man-based Al­fred We­gener In­sti­tute and a con­trib­u­tor to the work of the In­ter­gov­ern­men­tal Panel on Cli­mate Change.

“There’s a high risk of los­ing up to 90 per­cent of coral reefs in a 1.5-de­gree Cel­sius warmer world by the end of the cen­tury. This is a sys­tem that has al­ready gone be­yond its tol­er­ance lim­its,” he said. — Reuters

SVALBARD, Nor­way: A po­lar bear stands on an ice floe near the Arc­tic ar­chi­pel­ago of Svalbard, Nor­way. Sci­en­tists said yes­ter­day that Svalbard has seen such ex­treme warmth this year that the av­er­age an­nual tem­per­a­ture could end up above freez­ing for the first time on record. — AP

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