From wikipedia:

Carbon dioxide levels reached astounding heights and the sea levels elevated. Plants such as plankton became "glassy" and temperatures increased.

What does glassy mean in this context? I found several definition but am not sure which one apply here:

Are the plant turning into glass (akin to vitrification), or are they just dying?

  • Do not worry. Nothing turns into glass. It is a metaphor and it has the meaning of being smooth and shiny. Jul 29, 2016 at 11:01
  • 2
    @JennyWilson: it is not a metaphor.
    – JavaLatte
    Jul 29, 2016 at 12:57

3 Answers 3


It is not a well researched web page. But the meaning is literal: it means "like glass"

Forminafera are a type of single cell creature, rather like an amoeba, but with a shell. The shells can be made of various different materials.

The shells (called "tests") have a variety of appearances, when viewed under a microscope. Some appear "porcelaneous", they look like fine china, with a shiny white surface. Others have a fine structure that allows light to pass through. The appear like soap bubbles or blown glass. They are not actually made of glass, they are made of a form of calcium carbonate called calcite. These shells are good indicators of sea temperatures, and the white chalk cliffs and limestones are made of trillions of forminafera tests.

Forminafera by J.R Haynes gives details.

  • If you look at the references cited on the article, the phrase "glassy" planktic foraminifera appears. The author of the Wikipedia must have copy pasted the "glassy" part. Your answer provides the missing explanation. Very interesting, thank you! Jul 29, 2016 at 16:04

During the Cretaceous period, a new species of plankton, called Diatoms, evolved. One of their distinctive features is that they live in a shell made of silica, the material that glass is made from. They are quite literally glassy.

  • Your answer is good and clear. But following the links from wikipedia I think it is forminafera, not diatoms, though this doesn't make your answer wrong.
    – James K
    Jul 29, 2016 at 15:58
  • Good research, @JamesK! You are right.
    – JavaLatte
    Jul 29, 2016 at 16:27

enter image description hereYou've got it right!

The increased CO2 levels will increase the temperature. Because of it, firstly, the plankton will convert into the glassy form by exposure to the extreme heat (vitrification). Then, they will gradually die because of the same reason.

You can see in the image that it's easy to convert the plankton in the 'glassy' form! In a way, this scientific report perfectly uses the metaphor 'glassy'.

Image courtesy: http://identidadgeek.com/

  • They don't vitrify, that takes temperatures over 1000 degrees! Nor do they die of heat. The glassy plankton have transparent calcite shells, and are well adapted to warm water.
    – James K
    Jul 29, 2016 at 16:01

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