Mini ocean creatures take help of light to avoid becoming fast food

Mid-ocean creatures take help of light to avoid becoming fast food

Having control over your reflection while living in an oceanic environment where light can be a matter of life and death is very important.

Many predators go deep down the ocean to search for ‘snacks’ and get it if they spot a silhouette of their prey. Others use searchlights on their heads to find something to eat.

For creatures who spend most of their life evading predators, having a transparent skin is one of their best chances of survival. However, in some instances, the same blessing can be a curse if a predator turns out to be a ‘fish carrying a lantern on its
head’.

Japetella heathi’s are small octopuses that usually live in mid-ocean and these creatures’ default state is transparent. Same is the case with Onychoteuthis banksii which is a five-inch deep sea squid.

These animals are as invisible as they come even if the ‘torch bearer’ sheds some light on them. However, these poor creatures don’t have any means of avoiding blue light which turns their colour to red thus making them an easy snack for predators.

Experiments conducted on board a ship in the Peru-Chile trench last year proved this theory. Both specimens were exposed to a blue-filtered LED light and the creatures turned from clear to opaque. They reverted to their default state (transparent) when the
light was removed.

15 to 20 different species of cephalopods were subjected to these tests by Dr Zylinski this year and it was noticed that the colour changing phenomena vary with the depth of the ocean.

"Smaller young animals are found higher in the water column and have fewer chromatophores, so they are more reliant on transparency, which makes sense because there won’t be predators using searchlights there," Zylinski says.

This research was funded by the US Office of Naval Research and the National Science Foundation and will appear in this month’s edition of the Current Biology journal.

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Posted by Taimoor Tariq on Nov 14 2011. Filed under Sci-Tech. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry