Penguins manage muscle oxygen supplies while diving

Penguins are clever creatures --- turns out they adjust their oxygen consumption based on how they are diving. Great stuff!

Penguins' Oxygen Trick: How They Survive Deep Dives
Jennifer Welsh, LiveScience Staff Writer ~ 12 May 2011
http://www.livescience.com/14117-penguin-diving-feat-oxygen-trick.html

And a very nifty graphic:
http://www.livescience.com/14125-deepest-divers-emperor-penguins-ocean-life.html

Penguins are the acrobatic athletes of the seas, and they can keep diving for long periods of time because they have exquisite control over how and when their muscles use oxygen, new research indicates.

The penguins can switch between two modes of oxygen use — either starving their muscles or giving them an extra shot of oxygen to keep them working — to achieve their amazing dives.

"It appears that there's a little bit of plasticity or variability in what they do when they are diving," said study researcher Cassondra Williams of the University of California in San Diego. "It's much more complicated than we thought."

To figure out how penguins survive deep dives on a single breath of air, the researchers designed special probes to monitor the levels of oxygen in the penguins' muscles during their dives off McMurdo Sound, Antarctica. The results are based on three emperor penguins and 50 dives, which ranged from 23 to 210 feet (7 to 64 meters) in depth, which lasted from 2.3 to 11.4 minutes.

"They have two different patterns they can opt for while they are diving," Williams told LiveScience. "In one, they appear to cut off blood flow completely to the muscle, leaving it to rely on its own supplies, which leaves the blood oxygen for the rest of the body, like the brain and the heart."

In other dives, the researchers saw a plateau after the initial oxygen drop. They believe that the penguin is selectively sending extra oxygen from the blood into the muscles, so they don't get tired. They can only do this for a limited time, though, until blood oxygen levels become too low for the rest of the body. Eventually the penguins need to come up for air.

Cutting off the oxygen supply to the muscles forces them to start making energy using "anaerobic" respiration, which is done without oxygen. It has a downfall, though; it produces abyproduct called lactic acid that can be toxic in high doses.

If the penguins let the lactic acid accumulate in their muscles, it takes longer to recuperate after a long dive, the researchers believe. This may be why on some dives the penguins send extra oxygen. For example, an extra oxygen shot might be beneficial if the penguins are taking several dives during a short stint to, say, chase down a school of fish and don't want to lose the feeding opportunity while they spend additional time on the ice recuperating.

"They don't want to hit their aerobic limit and accumulate lactic acid, but it's not clear how or why they do that," Williams said.

The study was published May 12 in the Journal of Experimental Biology.

Whale wars in the courts and on the Seas --- Australia is suing Japan over Antarctic Whaling

Australia is upping the ante here; with the recent 'failed' Antarctic whaling season that Japan ended early due to Sea Shepherd's efforts, plus legal action against them, it hasn't looked better to be a cetacean since humans started using tools.

Australia Takes Case To Stop Japan Whaling To International Court
http://www.nasdaq.com/aspx/stock-market-news-story.aspx?storyid=201105082137dowjonesdjonline000099&title=australia-takes-case-to-stop-japan-whaling-to-international-court

SYDNEY - Australia's government Monday will lodge a written submission at the International Court of Justice calling for an end to Japan's whaling program in the Antarctic ocean and setting the Pacific allies up for a prolonged legal spat.

Japan says it engages in whaling for scientific research and rejects Canberra's charges that the country is breaching the International Convention for the Regulation of Whaling and a ban on whaling inthe Southern Ocean Sanctuary.

Legal action between the two countries became a reality in 2010 after years of agitation failed to win a breakthrough, prompting Australia's then Prime Minister Kevin Rudd to opt for the Hague-based ICJ in an effort to end Japan's Southern Ocean whaling program and win support for a global ban on whaling.

"Despite Australia repeatedly calling on Japan to cease its illegal whaling activities, Japan has refused to do so. That is why the Australian Government has taken this case in the ICJ," the Australian government said in a statement.

The Antarctic Ocean, also known as the Southern Ocean, stretches from the continent of Antarctica in the south but does not have a clearly defined northern limit.

Killed for their oils, five whale species in Australian waters are listed for protection by the government, including the humpback and blue whales.

Australia has been monitoring Japan's activity in the waters in recent years and there have been frequent clashes between anti-whaling protesters such as the Sea Shepherd Conservation Society and Japanese whaling boats.

Australia's submission will not be publicly released until the International Court of Justice decides on it. Japan has until March 2012 to respond. "The Government believes the whaling carried out by Japan is commercial, not scientific, and does not fall within that narrow exception," the Australian statement said.

-By Enda Curran, Dow Jones Newswires; 61-2-8272-4687; enda.curran@dowjones.com