The impact of rising temperatures on animal and plant life is being measured across the world. Numerous studies are documenting latitudinal shifts in wildlife populations on land and sea – from butterflies to sea snails.

Scientists Somero and Stillman study how a minimal temperature change could affect the intertidal porcelain crab.

In California tide pools, similar changes are being witnessed as southern species progressively move into more northern reaches, driven by warming.

Research studies indicate some species may be subjected to severe physiological stresses before they relocate. Physiologists George Somero and Jonathon Stillman are studying how a simple one-degree change in temperature could affect the intertidal porcelain crab. In an experiment to test the thermal tolerance of these crabs, Stillman hooked up the small animals to a heart rate monitor, immersed them in water and gradually increased the temperature. He discovered that those crabs currently experiencing the biggest daily temperature swings are already just about at their limit. Their hearts stop beating in water only two degrees Fahrenheit warmer than what they currently experience in the wild. With global warming increasing, these crabs are edging ever closer to their absolute limits.

Related Links
»	To see a dramatic visualization of how climate change may affect the Great Lakes region of the U.S over the coming century, visit Migrating Climates —part of the Union of Concerned Scientists website.
»	A comparative analysis of the upper thermal tolerance limits of eastern Pacific porcelain crabs, genus Petrolisthes: Influences of latitude, vertical zonation, acclimation and phylogeny by J. Stillman and G. Somero.
»	More information on animal and plant movements in response to global warming.

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