How does the pH of fresh glacial meltwater compare to marine seawater?
In general, the pH of seawater can range from 7.5 to 8.4 depending on where you are in the world, this is due to temperature differences, shipping activity, pollution, and several other factors. Reefs are quite sensitive to pH and are usually found in bodies of water with a pH ranging from 8.0 - 8.4. Glacial water should be nearly neutral as most glaciers were formed thousands of years ago when pollution levels were relatively low. It is quite possible that the glacier would actually be very slightly acidic due to the carbon dioxide that would have been trapped in the ice when it formed bubbling through the water creating a very weak carbonic acid. Scientists actually measure the levels of carbon dioxide in the ice to get an idea of what the Earths atmosphere was like thousands of years ago.

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