pH: What is it?

"pH" is an abbreviation for "power of hydrogen" or "potential hydrogen." (What 'p' actually stands for is disputed, but it's the 'H' that's important.) Hydrogen is vital to pH because the amount of hydrogen ions in a water-based solution (which is a liquid that's a combination of water and something else) dictates how acidic something is. Because hydrogen ions are so tiny and it takes many thousands of ions to make a measurable difference in pH, the pH scale is logarithmic: each number of the scale represents a change that's an order of magnitude larger or smaller than its neighboring number. That means that stomach acid is ten times more acidic than lemon juice, and a hundred times more acidic than cola.

The pH of the ocean and coast has a massive effect on animals and the ecosystem. Animals like fish, shellfish, and corals have a certain pH range in which they can thrive. Corals, for example, have a very low tolerance for changes in pH; increasing coastal and ocean acidification is already wrecking havoc on reefs and causing massive die-offs. Closer to home, bay scallops are an example of an animal that appears to be very sensitive to shifts in pH, and studies have shown that even slight changes have a big effect on scallops' growth and survival. That's worrying not only because scallops are part of our coastal ecosystem, but because they're the most valuable commercial fishery in our region.