"As more and more carbon dioxide is absorbed by the oceans, it's going to spread from the poles to the tropics."
There's also question whether Arctic organisms are more vulnerable than their tropical counterparts, Kleypas said.
Northern critters might be able to adapt more successfully to changing ocean chemistry than tropical coral reefs, which Kleypas compared to "spoiled brats" that have existed for eons in comfortably stable, higher pH waters.
Indeed, the situation in the Arctic could be akin to adding a few degrees to the summertime highs in Phoenix, she said: the typical resident, well-adapted to the heat, wouldn't have to do much to adjust.
But force that same increase upon someone living in Hawaii, where temperatures stay comfortably constant, and the change is unbearable.
"If they're already used to (stress), they've figured out a way to deal with it," she said.
"Not that people are wrong," she added. But "we're assuming things we shouldn't assume yet."
Still, both Kleypas and Harrould-Kolieb cautioned that acidification's consequences are profound and need to be taken seriously, whether in the tropics or at the poles.
Mathis, who agreed that the full range of acidification's effects remains uncertain, said it's clear at this point that the changing oceans pose a threat to Alaska's commercial fisheries and subsistence communities today.
"Ecosystems in Alaska are going to take a hit from ocean acidification," said Mathis.
"Right now, we don't know how they are going to respond."
* *Note (8/28/09): Scientists estimate that seawater's average pH is 8.1 today versus 8.2 in preindustrial times. Given the logarithmic pH scale, that represents a 30 percent increase in acidity.