Scientists Place Humboldt Squid In Simulated 2100 AD Ocean Water - Metabolic Rate Drops By 1/3 - NS

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Rui Rosa of the University of Lisbon in Portugal and Brad Seibel of the University of Rhode Island, put jumbo squid in tanks that mimicked the warmer and more acidic ocean conditions expected for 2100 if industrial emissions of greenhouse gases are not curbed. The team found that the squid's metabolic levels dropped by one third and the length of time the squid spent contracting their muscles dropped by almost half.

Jumbo squid blood carries very little oxygen - with each cycle through its body, the oxygen can be used up entirely. This means they must "recharge" constantly, and makes the animals very dependent on what oxygen is available in the water around them. Yet, the warmer water is, the smaller the amount of oxygen it can hold.

To make matters worse, the squid's blood cells are able to carry even less oxygen in acidic water. The bottom line is that jumbo squid in warm, acidic sea water are more lethargic, says Rosa. "They may become more susceptible to predators and less able to capture prey." Last year, the first study to simultaneously track a predator and its prey suggested that sperm whales may take advantage of moments when jumbo squid slow down to catch them.

The tracking study also showed that jumbo squid undertake a daily migration between the surface and the deep ocean. Rosa and Seibel say in future, the range they are able to survive in will become narrower, possibly forcing them to find new habitats. In fact, there are already signs that changes in the oceans are pushing jumbo squid into new waters. Surveys carried out by the Monterey Bay Aquarium show that over the past 16 years, the squid have become permanent residents of Californian waters. It is believed that warmer temperatures have helped push them north of their usual hunting grounds off Mexico and Central America.

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http://www.newscientist.com/article/dn16278-squids-in-acid-what-future-oceans-hold-in-store-.html