9
$\begingroup$

Is it possible to genetically engineer transparent carapace to act as biological armor in marine organisms?

I know that deep sea animals may have transparent skin to hide themselves in the lightless depths, but I havent seen any examples (so far) of transparent carapace. If you can make skin and organs transparent, can you do it for bones too?

$\endgroup$
1
  • 2
    $\begingroup$ How transparent are you looking for? Are you looking for window-glass transparency with no distortion, or are you just looking to let light through $\endgroup$
    – Cort Ammon
    Sep 28, 2018 at 19:08

3 Answers 3

2
$\begingroup$

As pictures in @Dubukay's answer illustrate, it will be transparent enough to see internal organs. However, you cannot get complete invisibility, because there is a difference in the index of refraction between seawater and the animal's skin/shell.

Pure water has an index of refraction of 1.333. The refractive index of seawater varies with conditions, but is within the range of 1.329 and 1.368.

The carapace of arthropods/crustaceans is made of the protein chitin. The scales and skin of fish and marine mammals is made of the protein keratin. Both have refractive indices above 1.5:

Refractive index and dispersion of butterfly chitin and bird keratin measured by polarizing interference microscopy

Using Jamin-Lebedeff interference microscopy, we measured the wavelength dependence of the refractive index of butterfly wing scales and bird feathers. The refractive index values of the glass scales of the butterfly Graphium sarpedon are, at wavelengths 400, 500 and 600 nm, 1.572, 1.552 and 1.541, and those of the feather barbules of the white goose Anas anas domestica are 1.569, 1.556 and 1.548, respectively.

abstract on PubMed

The only way for one transparent material to completely "disappear" inside another is for the refractive indices to match. As you can see, this won't happen.

$\endgroup$
7
$\begingroup$

Yes, absolutely!

Check out this little guy:

Copepod suspended in water column, personal photo

This is a copepod. They live basically everywhere and are one of the most numerous animal groups in aquatic communities.

They also belong to the subphylum Crustacea, the same group of animals as the more charismatic crabs and lobsters of which you're probably thinking. Their carapace is quite strong, but still translucent and almost glasslike in places.

Other examples:

The aptly named ghost shrimp

Ghost shrimp, from https://aquariuminfo.org/images/ghostshrimp.jpg

A common marine isopod

Translucent isopod, from https://arthropoda.wordpress.com/category/arthropods/crustaceans/isopods-pill-bugs/

Even some lobsters can have translucent shells:

Ghost lobster, from https://www.newsweek.com/extremely-rare-translucent-ghost-lobster-caught-coast-maine-659093

$\endgroup$
5
$\begingroup$

A carapace is typically chitin rather than bone. Some species of shrimp have completely transparent carapaces. hardness and transparency of the carapace are largely determined by the degree of mineralization. Ghost Shrimp have transparent carapaces, and the carapace of many crayfish is actually translucent.

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .