Natures wonders: using pH (Introduction)

by David Turell @, Monday, June 09, 2014, 16:29 (1445 days ago) @ David Turell

Cat fish fish by following a more acid pH to get the worm:

"they found that the fish respond most strongly to slight variations in the acidity of seawater. This is measured on the pH scale: 0 is completely acidic, 7 is neutral and 14 is completely alkaline. Seawater normally varies between 8.1 and 8.2, but Caprio found that a drop of just 0.1 ... a slight increase in acidity ... was enough to get the fish hunting.

"It's quite dramatic," says Caprio. "The fish is like a swimming pH meter."

"Like all animals, the worms breathe out carbon dioxide, and this reacts with water to form carbonic acid, slightly acidifying it. Caprio found this was enough to temporarily acidify the water at the mouth of a worm's tunnel, reducing pH by around 0.1. He covered the tunnel exits with netting to stop the worms being sucked out, and found the catfish repeatedly targeted the occupied tunnels and mostly ignored empty ones."

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