Carbonate

Ammonium carbonate is an organic compound.

Most structures that we call "coral" are, in fact, made up of hundreds to thousands of tiny coral creatures called polyps. Each soft-bodied polyp—most no thicker than a nickel—secretes a hard outer skeleton of limestone (calcium carbonate) that attaches either to rock or the dead skeletons of other polyps.

When CO₂ is absorbed by seawater, a series of chemical reactions occur resulting in the increased concentration of hydrogen ions. This increase causes the seawater to become more acidic and causes carbonate ions to be relatively less abundant.

Decreases in carbonate ions can make building and maintaining shells and other calcium carbonate structures difficult for calcifying organisms such as oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton.

Parrotfish bite and scrape algae off of rocks and dead corals with their parrot-like beaks; grind the inedible calcium carbonate (reef material made mostly of coral skeletons) which is excreted as sand back onto the reef.

Over time, that calcium carbonate forms tall, rocky seamounts around the methane vents. Victoria Orphan suspected that these rocky areas served as a shelter for sea life. So she found a submersible — a small vehicle like a submarine — and went down 800 meters to the sea floor to prove it.

Scientists wanted to see how these developing larvae were being affected by the increased acidity of the ocean water caused by excess carbon dioxide in the atmosphere. Whitman Miller — an environmental scientist and ecologist with the Smithsonian research center — says oceans normally absorb about half of the carbon dioxide that's produced by living creatures. But when excess CO₂ is pumped into the atmosphere and dissolves into seawater, that contributes to an acidification, or a lowering of the pH of the oceans. A byproduct of that process — carbonic acid — rapidly converts to carbonate and bicarbonate ions, which Miller says are corrosive to the calcium carbonate shells of oysters and other marine species.

A sample of carbon removed from the ocean in the solid form of calcium carbonate and magnesium hydroxide from UCLA's SeaChange program -- now known as Equatic -- in 2023.

McCoy’s team, including 66 researchers across four continents, found the salt and minerals left behind as water on Bennu, or its larger parent asteroid, evaporated. The minerals include sodium phosphates, carbonates, sulfates, chlorides and fluorides, some of which are necessary to the formation of life.