Armor-plated plankton getting weaker. And so is the planet.

The world’s future supply of chalk is threatened by global warming. That’s what I take away from this LiveScience report on how the souring of the ocean is weakening plankton shells:

In the new study, a trio of scientists at the Helmholtz Center for Oceanographic Research in Kiel, Germany, bred a variety of phytoplankton, called Emiliania huxleyi, to tolerate higher levels of carbon dioxide dissolved in the water.

They focused on these creatures for two reasons: Like other phytoplankton, E. huxleyi forms the bases of many of the ocean’s food chains. In addition, this creature is a coccolithophore, which builds its shell of calcium carbonate. That shell-building can be affected by the acidity of the oceans, with more acidic oceans holding less of their shell material.

To find out how this change and future changes might impact the armored plankton, researchers Kai Lohbeck, Ulf Riebesell and Thorsten Reusch took the plankton they had bred in the lab and exposed it to concentrations of carbon dioxide up to four times that in the atmosphere. They found that it can adapt, and even maintain its shell-building, though it doesn’t exactly thrive. “They do less badly,” Reusch said.

Reusch noted that altering the water chemistry can also affect how nutritious the plankton are for the other creatures that eat them, because it affects their metabolism. “They become like french fries,” he said. “The carbon-nitrogen balance becomes worse,” which affects nutrients needed by those that feast on them, such as zooplankton — tiny jellyfish, copepods and shrimp.

Chalk aside, one of the big problems is that the calcium carbonate in those coccolithophore shells contains a fair amount of carbon, which they get from carbon dioxide… which they get by socking away greenhouse gases. Less calcium carbonate, hotter atmosphere.