The Chemistry of an Octopus


They change color instantaneously. They change their skin texture. They fit into every nook and cranny of the sea. They ink, and it’s not as cute and harmless as Pearl made it out to be. Octopi are pretty much aliens on Earth. Due to our landlocked positioning in Montana, we’re more familiar with bison and beef than the mysteries of the deep. It’s time we change that!

Composition of ...

All life is composed of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. The different combinations create the biodiversity we have here.

Main Chemicals, Compounds, Components

Octopi have some incredible physical abilities. Here, I am focusing on their color-changing ability and ink composition.

They are able to change colors so well and so rapidly because of the pigmentary cells in their skin. These include: chromatophores, iridophores, and leucophores. Chromatophores create the yellows, reds, and browns; iridophores create metallic pinks, greens, yellows, blues, and silver. Leucophores reflect light.

Octopi ink is composed of amino acids, melanin, and products of the metabolism of tyrosinase (involved in the production of melanin). The amino acids include taurine, aspartic acid, glutamic acid, alanine, and lysine.

Chemistry's Role

The chemical composition of the amino acids involved in creating ink include: taurine (C2H7NO3S), aspartic acid (C4H7NO4), glutamic acid (C5H9NO4), alanine (C3H7NO2), lysine (C6H14N2O2)

Background Research

Understanding colors involves a high level of chemistry and physics. Visible light is the part of the electromagnetic spectrum that has wavelengths ranging from 400 to 700 nanometers. When we see something of color, the particles in that substances are absorbing all colors EXCEPT that color. What we see is what we don’t get.


mollusk ink

composition of taurine, aspartic acid, glutamic acid, alanine, and lysine (components of ink).

how colors work

About the Author

Chrissy Webb is a senior at Billings Senior High. IN the fall, she will attend the University of Montana to do science and explore the great outdoors.