Wednesday, November 29, 2006

NZ experiment to sink and study dead whales

NZ experiment to sink and study dead whales 21 November 2006 A decaying whale carcass can create an oasis of nutrients on the seafloorfor 70 years or more. Kent Atkinson reports on plans to sink a few deadwhale off the NZ coast. Scientists are looking at towing dead whales from strandings on NewZealand's coast and sinking them at a site where the extensive ecologicalsystems that build up on them can be studied. The fatty bones of dead whales were discovered 10 years ago to host carpetsof creatures - including bacteria and worms - similar to those found livingon the methane and sulphides from both super-hot seafloor vents, andicy-cold methane "seeps". These whale carcases - known as "whale falls" - deliver a bounty ofsulphur-laden ooze and other nutrients, similar to an oasis on desert-likestretches of ocean floor, but are hard to find and study. National Institute of Water and Atmospheric Research (Niwa) scientist AshleyRowden outlined the plan to sink whale carcasses for study, as he stood onthe Niwa research vessel Tangaroa, at Miramar, in Wellington yesterday. The vessel has just finished an international scientific expedition to studyorganisms at cold methane seeps off the east coast of the North Island, andDr Rowden said NZ was unusual in having a range of other environments wherethe food chain was rooted in methane or sulphide compounds. They include the super-heated hydrothermal vents of the Kermadec Arc, aswell as whale "falls" where organisms existed on the methane-rich content ofa carcass, and huge deposits of sunken timber on parts of the seafloor whichsupport similar life-forms.

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