Some like it hot…

For those of you who have not been in the know about the current state that our Earth is in, check out this video for a quick summary about global warming:


Global warming is a real issue that is affecting all of the Earth’s inhabitants. Lots of scientists are interested in its effects because of projected values on increases for the future. As the Earth warms, so do our oceans, which has a high impact on the organisms that inhabit it. Currently the oceans are warming at a rate of about 1/4 of a degree celsius per decade. Though, this may seem like a small amount, the rate at which the oceans are warming is exponential.

These factors led me to an experiment, studying the effects of increased temperature on marine species. I chose to do my experiment on Hemigrapsus oregonensis also known as the Yellow Shore crab or Green Shore crab. This species of crab is found in the rocky intertidal zones of the Pacific Ocean, spanning a geographic range from Baja, California up north to Alaska.


Like I mentioned, I wanted to study the effects of increased temperature on these crabs, but more specifically I wanted to see whether being exposed to elevated temperatures would cause a deviation in natural behaviours. These crabs are naturally found under rocks, in cold dark areas along the coast. So I expected them to have a preference towards these types of environments.

I created microhabitats (above) and placed the crabs in them to see whether or not they had a preference to a certain side of the microhabitats. The microhabitats differed in the temperature of the water beneath and that temperature was conducted through the aluminum foil. I provided three microhabitats for the crabs to experience. One testing their reaction to just temperature alone. Another adding a feature of shelter and finally simulating a shore bird predator.

I observed interesting results, at the lower temperatures the crabs behaved in a way that I had expected, choosing colder temperatures, shelter and predator free areas. However, at the highest elevated temperature, the crabs did in fact veer away from their natural instincts when exposed to extreme elevations in temperature despite shelter availability and the presence of a predator.

Knowing this, I can only presume that as ocean temperatures increase as a result of global warming, species will begin to deviate from their current normal behaviours in order to adapt to the changing temperatures. And if you really think about it, this would be insane! Can you imagine living in a word where animals weren’t afraid of their predators? Or where animals that once hid in the shadows now came out into the open? I don’t know about you, but as a person with a fear of spiders this doesn’t sound very appealing to me!

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